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Sample records for affect additional nitrogen

  1. Long-term warming and litter addition affects nitrogen fixation in a subarctic heath

    DEFF Research Database (Denmark)

    Sørensen, Pernille Lærkedal; Michelsen, Anders

    2011-01-01

    Nitrogen (N) availability is the main constraint on primary production in most Arctic ecosystems, with microbial fixation of atmospheric N as the primary source of N input. However, there are only few reports on N fixation rates in relation to climate change in the Arctic. In order to investigate...... years before the measurements. We analyzed N fixation rates on both whole-ecosystem level and specifically on two moss species: Sphagnum warnstorfii and Hylocomium splendens. The whole-ecosystem N fixation of the warmed plots almost tripled compared with the control plots. However, in the Sphagnum and...... Hylocomium mosses we observed either no change or occasionally even a decrease in N fixation after warming. Both measured on whole-ecosystem level and on the two moss species separately, litter addition increased N fixation rates. The results suggest that warming will lead to a general increased ecosystem N...

  2. Nitrogen Addition as a Result of Long-Term Root Removal Affects Soil Organic Matter Dynamics

    Science.gov (United States)

    Crow, S. E.; Lajtha, K.

    2004-12-01

    A long-term field litter manipulation site was established in a mature coniferous forest stand at the H.J. Andrews Experimental Forest, OR, USA in 1997 in order to address how detrital inputs influence soil organic matter formation and accumulation. Soils at this site are Andisols and are characterized by high carbon (C) and low nitrogen (N) contents, due largely to the legacy of woody debris and extremely low atmospheric N deposition. Detrital treatments include trenching to remove roots, doubling wood and needle litter, and removing aboveground litter. In order to determine whether five years of detrital manipulation had altered organic matter quantity and lability at this site, soil from the top 0-5 cm of the A horizon was density fractionated to separate the labile light fraction (LF) from the more recalcitrant mineral soil in the heavy fraction (HF). Both density fractions and whole soils were incubated for one year in chambers designed such that repeated measurements of soil respiration and leachate chemistry could be made. Trenching resulted in the removal of labile root inputs from root exudates and turnover of fine roots and active mycorrhizal communities as well as an increase of available N by removing plant uptake. Since 1999, soil solution chemistry from tension lysimeters has shown greater total N and dissolved organic nitrogen (DON) flux and less dissolved organic carbon (DOC) flux to stream flow in the trenched plots relative to the other detrital treatments. C/N ratio and C content of both light and heavy fractions from the trenched plots were greater than other detrital treatments. In the lab incubation, over the course of a year C mineralization from these soils was suppressed. Cumulative DOC losses and CO2 efflux both were significantly less in soils from trenched plots than in other detrital treatments including controls. After day 150 of the incubation, leachates from the HF of plots with trenched treatments had a DOC/DON ratio significantly

  3. How nitrogen and sulphur addition, and a single drought event affect root phosphatase activity in Phalaris arundinacea.

    Science.gov (United States)

    Robroek, Bjorn J M; Adema, Erwin B; Venterink, Harry Olde; Leonardson, Lars; Wassen, Martin J

    2009-03-15

    Conservation and restoration of fens and fen meadows often aim to reduce soil nutrients, mainly nitrogen (N) and phosphorus (P). The biogeochemistry of P has received much attention as P-enrichment is expected to negatively impact on species diversity in wetlands. It is known that N, sulphur (S) and hydrological conditions affect the biogeochemistry of P, yet their interactive effects on P-dynamics are largely unknown. Additionally, in Europe, climate change has been predicted to lead to increases in summer drought. We performed a greenhouse experiment to elucidate the interactive effects of N, S and a single drought event on the P-availability for Phalaris arundinacea. Additionally, the response of plant phosphatase activity to these factors was measured over the two year experimental period. In contrast to results from earlier experiments, our treatments hardly affected soil P-availability. This may be explained by the higher pH in our soils, hampering the formation of Fe-P or Fe-Al complexes. Addition of S, however, decreased the plants N:P ratio, indicating an effect of S on the N:P stoichiometry and an effect on the plant's P-demand. Phosphatase activity increased significantly after addition of S, but was not affected by the addition of N or a single drought event. Root phosphatase activity was also positively related to plant tissue N and P concentrations, plant N and P uptake, and plant aboveground biomass, suggesting that the phosphatase enzyme influences P-biogeochemistry. Our results demonstrated that it is difficult to predict the effects of wetland restoration, since the involved mechanisms are not fully understood. Short-term and long-term effects on root phosphatase activity may differ considerably. Additionally, the addition of S can lead to unexpected effects on the biogeochemistry of P. Our results showed that natural resource managers should be careful when restoring degraded fens or preventing desiccation of fen ecosystems. PMID:19101022

  4. Long-term nitrogen additions increase likelihood of climate stress and affect recovery from wildfire in a lowland heath.

    Science.gov (United States)

    Southon, Georgina E; Green, Emma R; Jones, Alan G; Barker, Chris G; Power, Sally A

    2012-09-01

    Increases in the emissions and associated atmospheric deposition of nitrogen (N) have the potential to cause significant changes to the structure and function of N-limited ecosystems. Here, we present the results of a long-term (13 year) experiment assessing the impacts of N addition (30 kg ha(-1)  yr(-1) ) on a UK lowland heathland under a wide range of environmental conditions, including the occurrence of prolonged natural drought episodes and a severe summer fire. Our findings indicate that elevated N deposition results in large, persistent effects on Calluna growth, phenology and chemistry, severe suppression of understorey lichen flora and changes in soil biogeochemistry. Growing season rainfall was found to be a strong driver of inter-annual variation in Calluna growth and, although interactions between N and rainfall for shoot growth were not significant until the later phase of the experiment, N addition exacerbated the extent of drought injury to Calluna shoots following naturally occurring droughts in 2003 and 2009. Following a severe wildfire at the experimental site in 2006, heathland regeneration dynamics were significantly affected by N, with a greater abundance of pioneering moss species and suppression of the lichen flora in plots receiving N additions. Significant interactions between climate and N were also apparent post fire, with the characteristic stimulation in Calluna growth in +N plots suppressed during dry years. Carbon (C) and N budgets demonstrate large increases in both above- and below-ground stocks of these elements in N-treated plots prior to the fire, despite higher levels of soil microbial activity and organic matter turnover. Although much of the organic material was removed during the fire, pre-existing treatment differences were still evident following the burn. Post fire accumulation of below-ground C and N stocks was increased rapidly in N-treated plots, highlighting the role of N deposition in ecosystem C sequestration

  5. Nitrogen laser with additional components

    International Nuclear Information System (INIS)

    The development and construction of a Nitrogen laser with low cost domestic components is described. The model built is operated at 50 pulses per second with a 50 kW power per pulse at the ultraviolet 337.1 nm wavelength. (Author)

  6. A 6-year-long manipulation with soil warming and canopy nitrogen additions does not affect xylem phenology and cell production of mature black spruce

    OpenAIRE

    Madjelia Cangre Ebou eDAO; Sergio eRossi; Denis eWalsh; Hubert eMorin; Daniel eHoule

    2015-01-01

    The predicted climate warming and increased atmospheric inorganic nitrogen deposition are expected to have dramatic impacts on plant growth. However, the extent of these effects and their interactions remains unclear for boreal forest trees. The aim of this experiment was to investigate the effects of increased soil temperature and nitrogen (N) depositions on stem intra-annual growth of two mature stands of black spruce [Picea mariana (Mill.) BSP] in Quebec, Canada. During 2008-2013, the soil...

  7. A 6-Year-Long Manipulation with Soil Warming and Canopy Nitrogen Additions does not Affect Xylem Phenology and Cell Production of Mature Black Spruce

    OpenAIRE

    Dao, Madjelia C. E.; Rossi, Sergio; Walsh, Denis; Morin, Hubert; Houle, Daniel

    2015-01-01

    The predicted climate warming and increased atmospheric inorganic nitrogen deposition are expected to have dramatic impacts on plant growth. However, the extent of these effects and their interactions remains unclear for boreal forest trees. The aim of this experiment was to investigate the effects of increased soil temperature and nitrogen (N) depositions on stem intra-annual growth of two mature stands of black spruce [Picea mariana (Mill.) BSP] in Québec, QC, Canada. During 2008–2013, the ...

  8. A 6-year-long manipulation with soil warming and canopy nitrogen additions does not affect xylem phenology and cell production of mature black spruce

    Directory of Open Access Journals (Sweden)

    Madjelia Cangre Ebou eDAO

    2015-11-01

    Full Text Available The predicted climate warming and increased atmospheric inorganic nitrogen deposition are expected to have dramatic impacts on plant growth. However, the extent of these effects and their interactions remains unclear for boreal forest trees. The aim of this experiment was to investigate the effects of increased soil temperature and nitrogen (N depositions on stem intra-annual growth of two mature stands of black spruce [Picea mariana (Mill. BSP] in Quebec, Canada. During 2008-2013, the soil around mature trees was warmed up by 4 °C with heating cables during the growing season and precipitations containing three times the current inorganic N concentration were added by frequent canopy applications. Xylem phenology and cell production were monitored weekly from April to October. The 6-year-long experiment performed in two sites at different altitude showed no substantial effect of warming and N-depositions on xylem phenological phases of cell enlargement, wall thickening and lignification. Cell production, in terms of number of tracheids along the radius, also did not differ significantly and followed the same patterns in control and treated trees. These findings allowed the hypothesis of a medium-term effect of soil warming and N depositions on the growth of mature black spruce to be rejected.

  9. Soil biochemical responses to nitrogen addition in a bamboo forest.

    Directory of Open Access Journals (Sweden)

    Li-hua Tu

    Full Text Available Many vital ecosystem processes take place in the soils and are greatly affected by the increasing active nitrogen (N deposition observed globally. Nitrogen deposition generally affects ecosystem processes through the changes in soil biochemical properties such as soil nutrient availability, microbial properties and enzyme activities. In order to evaluate the soil biochemical responses to elevated atmospheric N deposition in bamboo forest ecosystems, a two-year field N addition experiment in a hybrid bamboo (Bambusa pervariabilis × Dendrocalamopsis daii plantation was conducted. Four levels of N treatment were applied: (1 control (CK, without N added, (2 low-nitrogen (LN, 50 kg N ha(-1 year(-1, (3 medium-nitrogen (MN, 150 kg N ha(-1 year(-1, and (4 high-nitrogen (HN, 300 kg N ha(-1 year(-1. Results indicated that N addition significantly increased the concentrations of NH4(+, NO3(-, microbial biomass carbon, microbial biomass N, the rates of nitrification and denitrification; significantly decreased soil pH and the concentration of available phosphorus, and had no effect on the total organic carbon and total N concentration in the 0-20 cm soil depth. Nitrogen addition significantly stimulated activities of hydrolytic enzyme that acquiring N (urease and phosphorus (acid phosphatase and depressed the oxidative enzymes (phenol oxidase, peroxidase and catalase activities. Results suggest that (1 this bamboo forest ecosystem is moving towards being limited by P or co-limited by P under elevated N deposition, (2 the expected progressive increases in N deposition may have a potential important effect on forest litter decomposition due to the interaction of inorganic N and oxidative enzyme activities, in such bamboo forests under high levels of ambient N deposition.

  10. Nitrogen addition to an O-1 tool steel

    Energy Technology Data Exchange (ETDEWEB)

    Rawers, J.; Uggoweitzer, P.

    1999-05-01

    A new processing technique makes nitrogen alloying possible by adding nitrogen under elevated nitrogen pressure to prealloyed Fe-C ingots during continuous casting, producing a whole new class of precipitation-free, iron-carbon-nitrogen alloys. When both carbon and nitrogen bulk concentration levels exceeded 0.5 wt%, a duplex fcc-/(bcc-bct-) Fe microstructure resulted that is iron carbide- and nitride-free. With increasing carbon and nitrogen concentrations, there was an increase in the retained fcc-Fe phase. In cooling rate studies, increasing carbon and nitrogen concentrations shifted the knee of the fcc-Fe-to-bcc-Fe phase time-temperature-transformation (T-T-T) curve to longer times. Hardness, compression strength, and wear resistance increased with increasing carbon and nitrogen concentrations and were superior to iron-carbon alloys without the nitrogen addition.

  11. Response of Dissolved Organic Matter to Warming and Nitrogen Addition

    Science.gov (United States)

    Choi, J. H.; Nguyen, H.

    2014-12-01

    Dissolved Organic Matter (DOM) is a ubiquitous mixture of soluble organic components. Since DOM is produced from the terrestrial leachate of various soil types, soil may influence the chemistry and biology of freshwater through the input of leachate and run-off. The increased temperature by climate change could dramatically change the DOM characteristics of soils through enhanced decomposition rate and losses of carbon from soil organic matter. In addition, the increase in the N-deposition affects DOM leaching from soils by changing the carbon cycling and decomposition rate of soil decay. In this study, we conducted growth chamber experiments using two types of soil (wetland and forest) under the conditions of temperature increase and N-deposition in order to investigate how warming and nitrogen addition influence the characteristics of the DOM leaching from different soil types. This leachate controls the quantity and quality of DOM in surface water systems. After 10 months of incubation, the dissolved organic carbon (DOC) concentrations decreased for almost samples in the range of 7.6 to 87.3% (ANOVA, pHumification index (HIX) showed the significant increase trends during the duration of incubation and temperature for almost the samples (ANOVA, psoil samples. During the experiment, labile DOM from the soils was consumed and transformed into resistant aromatic carbon structures and less biodegradable components via microbial processes. Both time and the temperature presented the statistically significant effects on DOM characteristics of soil samples while the N-addition exhibited the insignificant difference among the samples.

  12. Long-term nitrogen addition decreases carbon leaching in nitrogen-rich forest ecosystems

    Directory of Open Access Journals (Sweden)

    X. Lu

    2013-01-01

    Full Text Available Dissolved organic carbon (DOC plays a critical role in the carbon (C cycle of forest soils, and has been recently connected with global increases in nitrogen (N deposition. Most studies on effects of elevated N deposition on DOC have been carried out in N-limited temperate regions, with far fewer data available from N-rich ecosystems, especially in the context of chronically elevated N deposition. Furthermore, mechanisms for excess N-induced changes of DOC dynamics have been suggested to be different between the two kinds of ecosystems, because of the different ecosystem N status. The purpose of this study was to experimentally examine how long-term N addition affects DOC dynamics below the primary rooting zones (the upper 20 cm soils in typically N-rich lowland tropical forests. We have a primary assumption that long-term continuous N addition minimally affects DOC concentrations and effluxes in N-rich tropical forests. Experimental N addition was administered at the following levels: 0, 50, 100 and 150 kg N ha−1 yr−1, respectively. Results showed that seven years of N addition significantly decreased DOC concentrations in soil solution, and chemo-physical controls (solution acidity change and soil sorption rather than biological controls may mainly account for the decreases, in contrast to other forests. We further found that N addition greatly decreased annual DOC effluxes from the primary rooting zone and increased water-extractable DOC in soils. Our results suggest that long-term N deposition could increase soil C sequestration in the upper soils by decreasing DOC efflux from that layer in N-rich ecosystems, a novel mechanism for continued accumulation of soil C in old-growth forests.

  13. Long-term nitrogen addition decreases carbon leaching in a nitrogen-rich forest ecosystem

    Directory of Open Access Journals (Sweden)

    X. Lu

    2013-06-01

    Full Text Available Dissolved organic carbon (DOC plays a critical role in the carbon (C cycle of forest soils, and has been recently connected with global increases in nitrogen (N deposition. Most studies on effects of elevated N deposition on DOC have been carried out in N-limited temperate regions, with far fewer data available from N-rich ecosystems, especially in the context of chronically elevated N deposition. Furthermore, mechanisms for excess N-induced changes of DOC dynamics have been suggested to be different between the two kinds of ecosystems, because of the different ecosystem N status. The purpose of this study was to experimentally examine how long-term N addition affects DOC dynamics below the primary rooting zones (the upper 20 cm soils in typically N-rich lowland tropical forests. We have a primary assumption that long-term continuous N addition minimally affects DOC concentrations and effluxes in N-rich tropical forests. Experimental N addition was administered at the following levels: 0, 50, 100 and 150 kg N ha−1 yr−1, respectively. Results showed that seven years of N addition significantly decreased DOC concentrations in soil solution, and chemo-physical controls (solution acidity change and soil sorption rather than biological controls may mainly account for the decreases, in contrast to other forests. We further found that N addition greatly decreased annual DOC effluxes from the primary rooting zone and increased water-extractable DOC in soils. Our results suggest that long-term N deposition could increase soil C sequestration in the upper soils by decreasing DOC efflux from that layer in N-rich ecosystems, a novel mechanism for continued accumulation of soil C in old-growth forests.

  14. Grassland biodiversity bounces back from long-term nitrogen addition

    Science.gov (United States)

    Storkey, J.; MacDonald, A. J.; Poulton, P. R.; Scott, T.; Köhler, I. H.; Schnyder, H.; Goulding, K. W. T.; Crawley, M. J.

    2015-12-01

    The negative effect of increasing atmospheric nitrogen (N) pollution on grassland biodiversity is now incontrovertible. However, the recent introduction of cleaner technologies in the UK has led to reductions in the emissions of nitrogen oxides, with concomitant decreases in N deposition. The degree to which grassland biodiversity can be expected to ‘bounce back’ in response to these improvements in air quality is uncertain, with a suggestion that long-term chronic N addition may lead to an alternative low biodiversity state. Here we present evidence from the 160-year-old Park Grass Experiment at Rothamsted Research, UK, that shows a positive response of biodiversity to reducing N addition from either atmospheric pollution or fertilizers. The proportion of legumes, species richness and diversity increased across the experiment between 1991 and 2012 as both wet and dry N deposition declined. Plots that stopped receiving inorganic N fertilizer in 1989 recovered much of the diversity that had been lost, especially if limed. There was no evidence that chronic N addition has resulted in an alternative low biodiversity state on the Park Grass plots, except where there has been extreme acidification, although it is likely that the recovery of plant communities has been facilitated by the twice-yearly mowing and removal of biomass. This may also explain why a comparable response of plant communities to reduced N inputs has yet to be observed in the wider landscape.

  15. Elevated CO2 promotes long-term nitrogen accumulation only in combination with nitrogen addition.

    Science.gov (United States)

    Pastore, Melissa A; Megonigal, J Patrick; Langley, J Adam

    2016-01-01

    Biogeochemical models that incorporate nitrogen (N) limitation indicate that N availability will control the magnitude of ecosystem carbon uptake in response to rising CO2 . Some models, however, suggest that elevated CO2 may promote ecosystem N accumulation, a feedback that in the long term could circumvent N limitation of the CO2 response while mitigating N pollution. We tested this prediction using a nine-year CO2 xN experiment in a tidal marsh. Although the effects of CO2 are similar between uplands and wetlands in many respects, this experiment offers a greater likelihood of detecting CO2 effects on N retention on a decadal timescale because tidal marshes have a relatively open N cycle and can accrue soil organic matter rapidly. To determine how elevated CO2 affects N dynamics, we assessed the three primary fates of N in a tidal marsh: (1) retention in plants and soil, (2) denitrification to the atmosphere, and (3) tidal export. We assessed changes in N pools and tracked the fate of a (15) N tracer added to each plot in 2006 to quantify the fraction of added N retained in vegetation and soil, and to estimate lateral N movement. Elevated CO2 alone did not increase plant N mass, soil N mass, or (15) N label retention. Unexpectedly, CO2 and N interacted such that the combined N+CO2 treatment increased ecosystem N accumulation despite the stimulation in N losses indicated by reduced (15) N label retention. These findings suggest that in N-limited ecosystems, elevated CO2 is unlikely to increase long-term N accumulation and circumvent progressive N limitation without additional N inputs, which may relieve plant-microbe competition and allow for increased plant N uptake. PMID:26577708

  16. Quantifying nitrogen leaching response to fertilizer additions in China's cropland.

    Science.gov (United States)

    Gao, Shuoshuo; Xu, Peng; Zhou, Feng; Yang, Hui; Zheng, Chunmiao; Cao, Wei; Tao, Shu; Piao, Shilong; Zhao, Yue; Ji, Xiaoyan; Shang, Ziyin; Chen, Minpeng

    2016-04-01

    Agricultural soils account for more than 50% of nitrogen leaching (LN) to groundwater in China. When excess levels of nitrogen accumulate in groundwater, it poses a risk of adverse health effects. Despite this recognition, estimation of LN from cropland soils in a broad spatial scale is still quite uncertain in China. The uncertainty of LN primarily stems from the shape of nitrogen leaching response to fertilizer additions (Nrate) and the role of environmental conditions. On the basis of 453 site-years at 51 sites across China, we explored the nonlinearity and variability of the response of LN to Nrate and developed an empirical statistical model to determine how environmental factors regulate the rate of N leaching (LR). The result shows that LN-Nrate relationship is convex for most crop types, and varies by local hydro-climates and soil organic carbon. Variability of air temperature explains a half (∼52%) of the spatial variation of LR. The results of model calibration and validation indicate that incorporating this empirical knowledge into a predictive model could accurately capture the variation in leaching and produce a reasonable upscaling from site to country. The fertilizer-induced LN in 2008 for China's cropland were 0.88 ± 0.23 TgN (1σ), significantly lower than the linear or uniform model, as assumed by Food and Agriculture Organization and MITERRA-EUROPE models. These results also imply that future policy to reduce N leaching from cropland needs to consider environmental variability rather than solely attempt to reduce Nrate. PMID:26774771

  17. Global response patterns of terrestrial plant species to nitrogen addition.

    Science.gov (United States)

    Xia, Jianyang; Wan, Shiqiang

    2008-07-01

    Better understanding of the responses of terrestrial plant species under global nitrogen (N) enrichment is critical for projection of changes in structure, functioning, and service of terrestrial ecosystems. Here, a meta-analysis of data from 304 studies was carried out to reveal the general response patterns of terrestrial plant species to the addition of N. Across 456 terrestrial plant species included in the analysis, biomass and N concentration were increased by 53.6 and 28.5%, respectively, under N enrichment. However, the N responses were dependent upon plant functional types, with significantly greater biomass increases in herbaceous than in woody species. Stimulation of plant biomass by the addition of N was enhanced when other resources were improved. In addition, the N responses of terrestrial plants decreased with increasing latitude and increased with annual precipitation. Dependence of the N responses of terrestrial plants on biological realms, functional types, tissues, other resources, and climatic factors revealed in this study can help to explain changes in species composition, diversity, community structure and ecosystem functioning under global N enrichment. These findings are critical in improving model simulation and projection of terrestrial carbon sequestration and its feedbacks to global climate change, especially when progressive N limitation is taken into consideration. PMID:19086179

  18. Nitrogen addition and warming independently influence the belowground micro-food web in a temperate steppe.

    Directory of Open Access Journals (Sweden)

    Qi Li

    Full Text Available Climate warming and atmospheric nitrogen (N deposition are known to influence ecosystem structure and functioning. However, our understanding of the interactive effect of these global changes on ecosystem functioning is relatively limited, especially when it concerns the responses of soils and soil organisms. We conducted a field experiment to study the interactive effects of warming and N addition on soil food web. The experiment was established in 2006 in a temperate steppe in northern China. After three to four years (2009-2010, we found that N addition positively affected microbial biomass and negatively influenced trophic group and ecological indices of soil nematodes. However, the warming effects were less obvious, only fungal PLFA showed a decreasing trend under warming. Interestingly, the influence of N addition did not depend on warming. Structural equation modeling analysis suggested that the direct pathway between N addition and soil food web components were more important than the indirect connections through alterations in soil abiotic characters or plant growth. Nitrogen enrichment also affected the soil nematode community indirectly through changes in soil pH and PLFA. We conclude that experimental warming influenced soil food web components of the temperate steppe less than N addition, and there was little influence of warming on N addition effects under these experimental conditions.

  19. CAN Canopy Addition of Nitrogen Better Illustrate the Effect of Atmospheric Nitrogen Deposition on Forest Ecosystem?

    Science.gov (United States)

    Zhang, Wei; Shen, Weijun; Zhu, Shidan; Wan, Shiqiang; Luo, Yiqi; Yan, Junhua; Wang, Keya; Liu, Lei; Dai, Huitang; Li, Peixue; Dai, Keyuan; Zhang, Weixin; Liu, Zhanfeng; Wang, Faming; Kuang, Yuanwen; Li, Zhian; Lin, Yongbiao; Rao, Xingquan; Li, Jiong; Zou, Bi; Cai, Xian; Mo, Jiangming; Zhao, Ping; Ye, Qing; Huang, Jianguo; Fu, Shenglei

    2015-06-01

    Increasing atmospheric nitrogen (N) deposition could profoundly impact community structure and ecosystem functions in forests. However, conventional experiments with understory addition of N (UAN) largely neglect canopy-associated biota and processes and therefore may not realistically simulate atmospheric N deposition to generate reliable impacts on forest ecosystems. Here we, for the first time, designed a novel experiment with canopy addition of N (CAN) vs. UAN and reviewed the merits and pitfalls of the two approaches. The following hypotheses will be tested: i) UAN overestimates the N addition effects on understory and soil processes but underestimates those on canopy-associated biota and processes, ii) with low-level N addition, CAN favors canopy tree species and canopy-dwelling biota and promotes the detritus food web, and iii) with high-level N addition, CAN suppresses canopy tree species and other biota and favors rhizosphere food web. As a long-term comprehensive program, this experiment will provide opportunities for multidisciplinary collaborations, including biogeochemistry, microbiology, zoology, and plant science to examine forest ecosystem responses to atmospheric N deposition.

  20. Nitrogen Addition Enhances Drought Sensitivity of Young Deciduous Tree Species.

    Science.gov (United States)

    Dziedek, Christoph; Härdtle, Werner; von Oheimb, Goddert; Fichtner, Andreas

    2016-01-01

    Understanding how trees respond to global change drivers is central to predict changes in forest structure and functions. Although there is evidence on the mode of nitrogen (N) and drought (D) effects on tree growth, our understanding of the interplay of these factors is still limited. Simultaneously, as mixtures are expected to be less sensitive to global change as compared to monocultures, we aimed to investigate the combined effects of N addition and D on the productivity of three tree species (Fagus sylvatica, Quercus petraea, Pseudotsuga menziesii) in relation to functional diverse species mixtures using data from a 4-year field experiment in Northwest Germany. Here we show that species mixing can mitigate the negative effects of combined N fertilization and D events, but the community response is mainly driven by the combination of certain traits rather than the tree species richness of a community. For beech, we found that negative effects of D on growth rates were amplified by N fertilization (i.e., combined treatment effects were non-additive), while for oak and fir, the simultaneous effects of N and D were additive. Beech and oak were identified as most sensitive to combined N+D effects with a strong size-dependency observed for beech, suggesting that the negative impact of N+D becomes stronger with time as beech grows larger. As a consequence, the net biodiversity effect declined at the community level, which can be mainly assigned to a distinct loss of complementarity in beech-oak mixtures. This pattern, however, was not evident in the other species-mixtures, indicating that neighborhood composition (i.e., trait combination), but not tree species richness mediated the relationship between tree diversity and treatment effects on tree growth. Our findings point to the importance of the qualitative role ('trait portfolio') that biodiversity play in determining resistance of diverse tree communities to environmental changes. As such, they provide further

  1. Effects of experimental nitrogen additions on plant diversity in tropical forests of contrasting disturbance regimes in southern China

    Energy Technology Data Exchange (ETDEWEB)

    Lu Xiankai [Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510160 (China); Mo Jiangming, E-mail: mojm@scib.ac.cn [Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510160 (China); Gilliam, Frank S. [Department of Biological Sciences, Marshall University, Huntington, WV 25755-2510 (United States); Yu Guirui [Institute of Geographical Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China); Zhang Wei; Fang Yunting; Huang Juan [Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510160 (China)

    2011-10-15

    Responses of understory plant diversity to nitrogen (N) additions were investigated in reforested forests of contrasting disturbance regimes in southern China from 2003 to 2008: disturbed forest (with harvesting of understory vegetation and litter) and rehabilitated forest (without harvesting). Experimental additions of N were administered as the following treatments: Control, 50 kg N ha{sup -1} yr{sup -1}, and 100 kg N ha{sup -1} yr{sup -1}. Nitrogen additions did not significantly affect understory plant richness, density, and cover in the disturbed forest. Similarly, no significant response was found for canopy closure in this forest. In the rehabilitated forest, species richness and density showed no significant response to N additions; however, understory cover decreased significantly in the N-treated plots, largely a function of a significant increase in canopy closure. Our results suggest that responses of plant diversity to N deposition may vary with different land-use history, and rehabilitated forests may be more sensitive to N deposition. - Highlights: > Nitrogen addition had no significant effect on understory plant diversity in the disturbed forest. > Nitrogen addition significantly decreased understory plant cover. > Nitrogen addition had no effect on richness and density in the rehabilitated forest. > The decrease is largely a function of a significant increase in canopy closure. > Land-use practices may dominate the responses of plant diversity to N addition. - Research in disturbed forests of southeastern China demonstrates that land-use history can substantially alter effects of excess nitrogen deposition on plant diversity of tropical forest ecosystems.

  2. [Effects of nitrogen addition on available nitrogen content and acidification in cold-temperate coniferous forest soil in the growing season].

    Science.gov (United States)

    Chen, Gao-Qi; Fu, Wa-Li; Luo, Ya-Chen; Gao, Wen-Long; Li, Sheng-Gong; Yang, Hao

    2014-12-01

    Based on a low-level and multi-form N addition control experiment, this study took cold-temperate coniferous forest in Daxing'an Ling as the research object. After long-term and continuous nitrogen addition in situ, the available nitrogen (NH4(+) -N & NO3(-) -N) contents and pH values of the soil (0-10 cm) were measured in the early growing season (May) and the peak growing season (August) in 2010, 2012 and 2013. The results showed that, the available nitrogen in the early and peak growing seasons was mainly NH4(+) -N which accounted for over 96% of the inorganic nitrogen content, while the content of NO3(-) -N was very low. With the time extension of nitrogen addition, the effects of nitrogen addition on the NH4(+) -N content in 0-10 cm soil were more obvious in the early growing season than that in the peak growing season, and the NH4(+) -N content was mainly affected by the type of nitrogen addition. On the contrary, the NO3(-) -N content in 0-10 cm soil was higher in the peak growing season than that in the early growing season. The effect of N input was obvious on NO3(-) -N content in both early and peak growing seasons, and low nitrogen treatment tended to promote the enrichment of NO3(-) -N. As time went on, the response of NH4(+) -N and NO3(-) -N content to N addition was changed from insignificant in the early stage to significant in the late stage. N addition had a significant impact on the pH value of the 0-10 cm soil in the early and peak growing seasons. The pH values of the soil with low nitrogen treatment and the soil in the peak growing season were relatively lower. With the extension of the nitrogen addition time, the response of pH value also turned from insignificant in the early stage to significant in the late stage. Because of the long-term and continuous nitrogen addition, the 0 - 10 cm soil in this cold-temperate coniferous forest was obviously acidified. PMID:25826942

  3. How inhibiting nitrification affects nitrogen cycle and reduces environmental impacts of anthropogenic nitrogen input.

    Science.gov (United States)

    Qiao, Chunlian; Liu, Lingli; Hu, Shuijin; Compton, Jana E; Greaver, Tara L; Li, Quanlin

    2015-03-01

    Anthropogenic activities, and in particular the use of synthetic nitrogen (N) fertilizer, have doubled global annual reactive N inputs in the past 50-100 years, causing deleterious effects on the environment through increased N leaching and nitrous oxide (N2 O) and ammonia (NH3 ) emissions. Leaching and gaseous losses of N are greatly controlled by the net rate of microbial nitrification. Extensive experiments have been conducted to develop ways to inhibit this process through use of nitrification inhibitors (NI) in combination with fertilizers. Yet, no study has comprehensively assessed how inhibiting nitrification affects both hydrologic and gaseous losses of N and plant nitrogen use efficiency. We synthesized the results of 62 NI field studies and evaluated how NI application altered N cycle and ecosystem services in N-enriched systems. Our results showed that inhibiting nitrification by NI application increased NH3 emission (mean: 20%, 95% confidential interval: 33-67%), but reduced dissolved inorganic N leaching (-48%, -56% to -38%), N2 O emission (-44%, -48% to -39%) and NO emission (-24%, -38% to -8%). This amounted to a net reduction of 16.5% in the total N release to the environment. Inhibiting nitrification also increased plant N recovery (58%, 34-93%) and productivity of grain (9%, 6-13%), straw (15%, 12-18%), vegetable (5%, 0-10%) and pasture hay (14%, 8-20%). The cost and benefit analysis showed that the economic benefit of reducing N's environmental impacts offsets the cost of NI application. Applying NI along with N fertilizer could bring additional revenues of $163 ha(-1)  yr(-1) for a maize farm, equivalent to 8.95% increase in revenues. Our findings showed that NIs could create a win-win scenario that reduces the negative impact of N leaching and greenhouse gas production, while increases the agricultural output. However, NI's potential negative impacts, such as increase in NH3 emission and the risk of NI contamination, should be fully

  4. The effects of warming and nitrogen addition on soil nitrogen cycling in a temperate grassland, northeastern China.

    Directory of Open Access Journals (Sweden)

    Lin-Na Ma

    Full Text Available BACKGROUND: Both climate warming and atmospheric nitrogen (N deposition are predicted to affect soil N cycling in terrestrial biomes over the next century. However, the interactive effects of warming and N deposition on soil N mineralization in temperate grasslands are poorly understood. METHODOLOGY/PRINCIPAL FINDINGS: A field manipulation experiment was conducted to examine the effects of warming and N addition on soil N cycling in a temperate grassland of northeastern China from 2007 to 2009. Soil samples were incubated at a constant temperature and moisture, from samples collected in the field. The results showed that both warming and N addition significantly stimulated soil net N mineralization rate and net nitrification rate. Combined warming and N addition caused an interactive effect on N mineralization, which could be explained by the relative shift of soil microbial community structure because of fungal biomass increase and strong plant uptake of added N due to warming. Irrespective of strong intra- and inter-annual variations in soil N mineralization, the responses of N mineralization to warming and N addition did not change during the three growing seasons, suggesting independence of warming and N responses of N mineralization from precipitation variations in the temperate grassland. CONCLUSIONS/SIGNIFICANCE: Interactions between climate warming and N deposition on soil N cycling were significant. These findings will improve our understanding on the response of soil N cycling to the simultaneous climate change drivers in temperate grassland ecosystem.

  5. Nitrogen Nutrition of Sugar Beet as Affected by Water Salinity, Proline Acid and Nitrogen Forms Using 15N Tracer Technique

    International Nuclear Information System (INIS)

    A pot experiment was conducted under green house condition using sugar beet as a test crop. Saline water (sea water) was applied at different levels. i.e. fresh water, 4 and 8 dSm-1. Labelled urea and ammonium sulphate (5% a.e.) were applied at rate of 120 kg N fed-1. Also; proline amino acid was sprayed at rate of 25, and 50 ppm. Basal recommended doses of P and K were applied. Crop leaves and tuber yield were severely affected by sea water salinity. These parameters were improved by adding proline acid. Effect of proline acid was significantly varied according to rate of addition, water salinity levels and N forms. In this respect, the improvement of leaves and tuber was more pronounced at rate of 50 ppm proline under 8 dSm-1 salinity when plants fertilized with ammonium sulfate. Another picture was drawn with urea, where the improvement was detected at rate of 25 ppm proline, under 4dSm-1 water salinity level. Nitrogen, phosphorus, potassium and sodium uptake by leaves and tuber of sugar beet plants were significantly improved by addition of 50 ppm proline under 4 and /or 8 dSm-1 salinity levels. Nitrogen uptake was higher in tuber and fertilization with urea than those of leaves and ammonium sulfate, respectively. Other nutrients were varied according to N forms and proline levels. Nitrogen use efficiency was enhanced by spraying proline, despite of addition rates, and negatively affected by increasing salinity levels. In this regard, no big significant difference was detected between urea and ammonium sulfat

  6. Nitrogen (15N) accumulation in corn grains as affected by source of nitrogen in red latosol

    International Nuclear Information System (INIS)

    Nitrogen is the most absorbed mineral nutrient by corn crop and most affects grains yield. It is the unique nutrient absorbed by plants as cation (NH4+) or anion (NO3-). The objectives of this work were to investigate the N accumulation by corn grains applied to the soil as NH4+ or NO3- in the ammonium nitrate form compared to amidic form of the urea, labeled with 15N; to determine the corn growth stage with highest fertilizer N utilization by the grains, and to quantify soil nitrogen exported by corn grains. The study was carried out in the Experimental Station of the Regional Pole of the Sao Paulo Northwestern Agribusiness Development (APTA), in Votuporanga, State of Sao Paulo, Brazil, in a Red Latosol. The experimental design was completely randomized blocks, with 13 treatments and four replications, disposed in factorial outline 6x2 + 1 (control, without N application). A nitrogen rate equivalent to 120 kg N ha-1 as urea-15N or as ammonium nitrate, labeled in the cation NH4+ (15NH4+NO3-) or in the anion NO3- (NH4+15N+O3- ), was applied in six fractions of 20 kg N ha-1 each, in different microplots, from seeding to the growth stage 7 (pasty grains). The forms of nitrogen, NH4+-N and NO3--N, were accumulated equitably by corn grains. The corn grains accumulated more N from urea than from ammonium nitrate. The N applied to corn crop at eight expanded leaves stage promoted largest accumulation of this nutrient in the grains. (author)

  7. Influence of carbohydrate addition on nitrogen transformations and greenhouse gas emissions of intensive aquaculture system.

    Science.gov (United States)

    Hu, Zhen; Lee, Jae Woo; Chandran, Kartik; Kim, Sungpyo; Sharma, Keshab; Khanal, Samir Kumar

    2014-02-01

    Aquaculture is one of the fastest-growing segments of the food economy in modern times. It is also being considered as an important source of greenhouse gas (GHG) emissions. To date, limited studies have been conducted on GHG emissions from aquaculture system. In this study, daily addition of fish feed and soluble starch at a carbon-to-nitrogen (C/N) ratio of 16:1 (w/w) was used to examine the effects of carbohydrate addition on nitrogen transformations and GHG emissions in a zero-water exchange intensive aquaculture system. The addition of soluble starch stimulated heterotrophic bacterial growth and denitrification, which led to lower total ammonia nitrogen, nitrite and nitrate concentrations in aqueous phase. About 76.2% of the nitrogen output was emitted in the form of gaseous nitrogen (i.e., N2 and N2O) in the treatment tank (i.e., aquaculture tank with soluble starch addition), while gaseous nitrogen accounted for 33.3% of the nitrogen output in the control tank (i.e., aquaculture tank without soluble starch addition). Although soluble starch addition reduced daily N2O emissions by 83.4%, it resulted in an increase of daily carbon dioxide (CO2) emissions by 91.1%. Overall, starch addition did not contribute to controlling the GHG emissions from the aquaculture system. PMID:24140689

  8. Comparison of Nitrogen Fertilizers, Induce and Zinc Addition on Glyphosate Efficacy on Three Different Weed Species.

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    Hussein F. Abouziena

    2014-05-01

    Full Text Available Herbicides are often tank-mixed with fertilizers to save time, labour, energy, and equipment costs. However addition of some additives with glyphosate may result in reducing glyphosate efficacy. Therefore we evaluated the potential of three nitrogen sources (ammonium sulphate (AMS at 2 or 4% w/v, ammonium nitrate (AN at 1 or 2% w/v, urea at 1 or 2 % w/v, nonionic adjuvant (Induce at 0.05% v/v and Zn at 250 g Zn/ha (1321 ppm to enhance glyphosate efficacy on pig weed (Amaranthus retroflexus L., crowfoot grass (Dactyloctenium egyptium L. and yellow nutsedge (Cyperus esculentus L. under greenhouse conditions. The results indicated that there were variations in susceptibility of the three weeds to glyphosate+adjuvant treatments. Addition of AN at 2% reduced the efficacy of glyphosate on crowfoot grass. There was an antagonistic effect between glyphosate herbicide and Zn; the phytotoxic effect of glyphosate on the three weeds was less than 50 %. Zinc tank-mixed with glyphosate resulted in a greater number of tubers and shoots per plant than the untreatedol. Addition of AN or urea at 2% reduced glyphosate efficacy by about 2.3 and 9 %, respectively, relative to their addition at 1%. Tankmixes of urea (1%, AN (1%, AMS (2% and Induce adjuvant (0.05% generally enhanced the efficacy of glyphosate (0.85 kg/ha, whereas the addition of Zn, as zinc sulphate, to glyphosate sprays adversely affected herbicide efficacy.

  9. Nitrogen saturation in humid tropical forests after 6 years of nitrogen and phosphorus addition

    DEFF Research Database (Denmark)

    Chen, Hao; Gurmesa, Geshere A.; Zhang, Wei;

    2016-01-01

    Nitrogen (N) saturation hypothesis suggests that when an ecosystem reaches N-saturation, continued N input will cause increased N leaching, nitrous oxide (N2O) emission, and N mineralization and nitrification rates. It also suggests that a different element will become the main limiting...

  10. Improved nitrogenous additives for engine fuels and additived engine fuels

    Energy Technology Data Exchange (ETDEWEB)

    Denis, J.; Montagnea, X.; Mulard, P.; Eber, D.

    1990-12-21

    Fuel additive for spark ignition engines inhibiting deposits on inlet valves comprising a polyglycol, soluble in the fuel, with a molecular weight between 480 and 2100 and two other components A and B, which are obtained by reaction of an alcenyl or polyalcenyl-succinic derivative on a polyamine for A and on a 1.2 hydroxyethyl imidazoline.

  11. Nitrogen-15 recovery fraction in flooded tropical rice as affected by Added Nitrogen Interaction

    International Nuclear Information System (INIS)

    The application of N fertilizer has been shown to cause an apparent increase in the uptake of native soil N via an effect termed ‘Added nitrogen interaction’ (ANI). This ANI caused by pool-substitution, can affect the 'IN-recovery fraction (NRF) by plants as calculated by the isotope-dilution method. The ANI effect was studied in a field experiment with transplanted and direct seeded flooded rice, comparing three methods of N-application (broadcast and incorporation of prilled urea ; band placement of urea solution ; and point placement of urea supergranules). ANI's for broadcast and incorporation treatments were generally greater than those for band and point placement treatments. The values for NRF calculated by the isotope-dilution method were lower than those of the apparent N-recovery fracton (ARF) as calculated by the difference method. Most of the discrepancy between plant nitrogen recoveries estimated by the isotope-dilution and the difference method could be explained by fertilizer losses and by pool-substitution, which means that fertilizer N stands proxy for soil N. (author)

  12. Soil carbon mineralization following biochar addition associated with external nitrogen

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    Rudong Zhao

    2015-12-01

    Full Text Available Biochar has been attracting increasing attention for its potentials of C sequestration and soil amendment. This study aimed to understand the effects of combining biochar with additional external N on soil C mineralization. A typical red soil (Plinthudults was treated with two biochars made from two types of plantation-tree trunks (soil-biochar treatments, and was also treated with external N (soil-biochar-N treatments. All treatments were incubated for 42 d. The CO2-C released from the treatments was detected periodically. After the incubation, soil properties such as pH, microbial biomass C (MBC, and microbial biomass N (MBN were measured. The addition of biochar with external N increased the soil pH (4.31-4.33 compared to the soil treated with external N only (4.21. This was not observed in the comparison of soil-biochar treatments (4.75-4.80 to soil only (4.74. Biochar additions (whether or not they were associated with external N increased soil MBC and MBN, but decreased CO2-C value per unit total C (added biochar C + soil C according to the model fitting. The total CO2-C released in soil-biochar treatments were enhanced compared to soil only (i.e., 3.15 vs. 2.57 mg and 3.23 vs. 2.45 mg, which was attributed to the labile C fractions in the biochars and through soil microorganism enhancement. However, there were few changes in soil C mineralization in soil-biochar-N treatments. Additionally, the potentially available C per unit total C in soil-biochar-N treatments was lower than that observed in the soil-biochar treatments. Therefore, we believe in the short term, that C mineralization in the soil can be enhanced by biochar addition, but not by adding external N concomitantly.

  13. 40 CFR Table 2 to Subpart Fff of... - Nitrogen Oxides Requirements for Affected Facilities

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Nitrogen Oxides Requirements for... Before September 20, 1994 Pt. 62, Subpt. FFF, Table 2 Table 2 to Subpart FFF of Part 62—Nitrogen Oxides Requirements for Affected Facilities Municipal waste combustor technology Nitrogen oxides emission limit...

  14. Mineral elements of subtropical tree seedlings in response to elevated carbon dioxide and nitrogen addition.

    Directory of Open Access Journals (Sweden)

    Wenjuan Huang

    Full Text Available Mineral elements in plants have been strongly affected by increased atmospheric carbon dioxide (CO2 concentrations and nitrogen (N deposition due to human activities. However, such understanding is largely limited to N and phosphorus in grassland. Using open-top chambers, we examined the concentrations of potassium (K, calcium (Ca, magnesium (Mg, aluminum (Al, copper (Cu and manganese (Mn in the leaves and roots of the seedlings of five subtropical tree species in response to elevated CO2 (ca. 700 μmol CO2 mol(-1 and N addition (100 kg N ha(-1 yr(-1 from 2005 to 2009. These mineral elements in the roots responded more strongly to elevated CO2 and N addition than those in the leaves. Elevated CO2 did not consistently decrease the concentrations of plant mineral elements, with increases in K, Al, Cu and Mn in some tree species. N addition decreased K and had no influence on Cu in the five tree species. Given the shifts in plant mineral elements, Schima superba and Castanopsis hystrix were less responsive to elevated CO2 and N addition alone, respectively. Our results indicate that plant stoichiometry would be altered by increasing CO2 and N deposition, and K would likely become a limiting nutrient under increasing N deposition in subtropics.

  15. Soil microbial responses to nitrogen addition in arid ecosystems

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    Robert L Sinsabaugh

    2015-08-01

    Full Text Available The N cycle of arid ecosystems is influenced by low soil organic matter, high soil pH and extremes in water potential and temperature that lead to open canopies and development of biological soil crusts (biocrusts. We investigated the effects of N amendment on soil microbial dynamics in a Larrea tridentata-Ambrosia dumosa shrubland site in southern Nevada USA. Sites were fertilized with a NO3-NH4 mix at 0, 7, and 15 kg ha-1 yr-1 from March 2012 to March 2013. In March 2013, biocrust (0-0.5 cm and bulk soils (0-10 cm were collected beneath Ambrosia canopies and in the interspaces between plants. Biomass responses were assessed as bacterial and fungal SSU rRNA gene copy number and chlorophyll a concentration. Metabolic responses were measured by five ecoenzyme activities (EEA and rates of N transformation. By most measures, nutrient availability, microbial biomass and process rates were greater in soils beneath the shrub canopy compared to the interspace between plants, and greater in the surface biocrust horizon compared to the deeper 10 cm soil profile. Most measures responded positively to experimental N addition. Effect sizes were generally greater for bulk soil than biocrust. Results were incorporated into a meta-analysis of arid ecosystem responses to N.

  16. Effects of wood-ash addition on nitrogen turnover in a highly nitrogen loaded spruce site. Final project report

    International Nuclear Information System (INIS)

    During two consecutive years, it was studied how a fertilization with 4.2 tonnes pelleted bark ash per ha, made six-seven years earlier, affected soil chemistry, nitrogen turnover and soil-water chemistry on a Norway spruce site in SW Sweden. The actual site has a very acidic soil. At the same time, the supply of inorganic N is rich. Measures against soil acidification, e. g. addition of ash or lime, may significantly influence the turnover of N with a subsequent risk for increased leaching. Thus, there is a potential conflict between two urgent environmental goals, i. e. to decrease acidification and to decrease the N load on aquatic ecosystems. In the humus layer and the upper 5 cm of the mineral soil, pH(H2O) had increased with at the most 0.2 units because of the ash addition. The easily extractable amounts of Mg, P and nitrate were slightly increased. The potential nitrification in the humus layer was generally higher in the ash treatment, but the difference. was not statistically significant. The soil water at 50 cm depth was 0.1-0.2 pH-units more acidic where ash had been applied. Simultaneously, there were tendencies for higher concentrations of nitrate, Al and K. This is the first time in Sweden that ash fertilization of a closed forest has given clear indications of an increased N leaching. As expected, the ash fertilization decreased the acidity of the top soil. On the contrary, the runoff became more acidic and more rich in Al. Thus, the ash fertilization has counteracted one of its primary goals, i. e. to produce a runoff less toxic to aquatic life. The acidification of the runoff may partially be because of acid production during nitrification

  17. The mechansims by which solute nitrogen affects phase transformations and mechanical properties of automotive dual-phase sheet steel

    Science.gov (United States)

    Brown, Tyson W.

    Dual-phase steels have seen increased use in automotive applications in recent years, in order to meet the goals of weight reduction and occupant safety. Variations in nitrogen content that may be encountered in steel sourced from a basic oxygen furnace process compared to an electric arc furnace process require that dual-phase steel producers understand the ways that nitrogen affects processing and properties. In the current work, the distribution of nitrogen was investigated in a dual-phase steel with a base chemistry of 0.1 C, 2.0 Mn, 0.2 Cr, 0.2 Mo (wt pct) across a range of nitrogen contents (30-159 ppm) with Al (0.2 and 0.08 wt pct), and Ti (0.02 wt pct) additions used for precipitation control of nitrogen amounts. The distribution of nitrogen amongst trapping sites, including precipitates, grain boundaries, dislocations, and interstitial sites (away from other types of defects) was determined from a combination of electrolytic dissolution, internal friction, and three-dimensional atom probe tomography experiments. Various mechanisms by which different amounts and locations of nitrogen affect phase transformations and mechanical properties were identified from quantitative metallography, dilatometric measurement of phase transformations, tensile testing, and nanoindentation hardness testing. Results indicate nitrogen that is not precipitated with Ti or Al (free nitrogen) partitions to austenite (and thus martensite) during typical intercritical annealing treatments, and is mostly contained in Cottrell atmospheres in martensite. Due to the austenite stabilizing effect of nitrogen, the presence of free nitrogen during intercritical annealing leads to a higher austenite fraction in certain conditions. Thus, the presence of free nitrogen in a dual-phase microstructure will lead to an increase in tensile and yield strengths from both an increase in martensite fraction, and an increase in martensite hardness due to solid solution strengthening. Despite the presence

  18. Nitrogen and dry matter dynamics in linseed as affected by the nitrogen level and genotype in a Mediterranean environment

    International Nuclear Information System (INIS)

    Linseed or oilseed flax (Linum usitatissimum L.) is an important source of edible and industrial vegetable oil and is grown widely in temperate regions around the world. Nitrogen, one of the most important nutrients for linseed, is often applied for higher yield and better quality. However, the effects of N level on dry matter and N accumulation, partitioning, and retranslocation have not yet been identified in linseed. A two-year field study was therefore conducted to determine the effects of N level on dry matter, N accumulation, partitioning, and retranslocation of three linseed cultivars (Livia, Lirina, Creola) grown in a Mediterranean environment under rain-fed conditions. It was found that N fertilization increased biomass at anthesis by an average of 47% and at maturity by an average of 38%, compared with the control. N fertilization increased the dry matter partitioning in leaves + flowers and stems at anthesis, and also in leaves + capsule vegetative components, stems, and seeds at maturity. Dry matter translocation was affected by N fertilization, growing season, and by the interaction between growing season and N treatment. In addition, N fertilization increased N retranslocation from the vegetative parts of the plant to the seed. Moreover, the N uptake by seeds was more affected by the seed yield and less affected by the seed N concentration. The present study indicates that N fertilization affects dry matter and N translocation in linseed. -- Highlights: ► Dry matter translocation was affected by N fertilization, year, and their interaction. ► HI was affected by N fertilization while NHI was not. ► N fertilization increased N retranslocation from the vegetative parts to the seed.

  19. Cucumber nitrogen utilization as affected by compost levels and nitrogen rates using 15N technique

    International Nuclear Information System (INIS)

    The beneficial effect of compost application to the sandy soil on dry matter production of shoots and fruits as well as its effect on l5N-uptake and nitrogen utilization percent of cucumber plant (Cucumis sativus L.) were studied under field conditions. Two types of natural compost (i.e. sugar cane bagasse (SC) and beet compost (BC)) with three levels (2, 4, 6 ton/fed) in addition to check treatment for each kind of compost (sheep manure with rate of 20 in/fed) combined with three rates of nitrogen fertilizer rates (50, 75, 100% from the recommended rate, i.e. 75 kg /fed) were used. The bagasse compost in both seasons gave a significantly higher response than the beet compost. There was a greet reduction in cucumber dry weight, N yield, Ndff%, FN yield and N utilization % of shoots and fruits as the level of compost application decreased. However, cucumber plants grown on high compost application level (6 ton/fed) were similar in their responses to plants grown on the check treatment. The results of N utilization indicated that the fertilizer utilization by the cucumber shoots and fruits during both seasons was significantly higher for the medium N rate (75% N) in comparison to the lowest fertigation treatment (50% N) and similar to the highest N fertigation rate (100% N). Generally, the results showed that under the experimental conditions to reach an acceptable yield with a high fertilizer utilization, it could be suggested to apply relatively medium rates of N fertigation (56.25 kg N/fed) combined with the high level ofSC compost application (6 t/fed) keeping in mind the regional site conditions

  20. Effects of water and nitrogen addition on species turnover in temperate grasslands in northern China.

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    Zhuwen Xu

    Full Text Available Global nitrogen (N deposition and climate change have been identified as two of the most important causes of current plant diversity loss. However, temporal patterns of species turnover underlying diversity changes in response to changing precipitation regimes and atmospheric N deposition have received inadequate attention. We carried out a manipulation experiment in a steppe and an old-field in North China from 2005 to 2009, to test the hypothesis that water addition enhances plant species richness through increase in the rate of species gain and decrease in the rate of species loss, while N addition has opposite effects on species changes. Our results showed that water addition increased the rate of species gain in both the steppe and the old field but decreased the rates of species loss and turnover in the old field. In contrast, N addition increased the rates of species loss and turnover in the steppe but decreased the rate of species gain in the old field. The rate of species change was greater in the old field than in the steppe. Water interacted with N to affect species richness and species turnover, indicating that the impacts of N on semi-arid grasslands were largely mediated by water availability. The temporal stability of communities was negatively correlated with rates of species loss and turnover, suggesting that water addition might enhance, but N addition would reduce the compositional stability of grasslands. Experimental results support our initial hypothesis and demonstrate that water and N availabilities differed in the effects on rate of species change in the temperate grasslands, and these effects also depend on grassland types and/or land-use history. Species gain and loss together contribute to the dynamic change of species richness in semi-arid grasslands under future climate change.

  1. Effects of Nitrogen and Phosphorus Additions on Carbon Cycling of Tropical Mountain Rainforests in Hainan, China

    Science.gov (United States)

    Lai, J.

    2015-12-01

    Nitrogen (N) and Phosphorus (P) deposition is projected to increase significantly in tropical regions in the coming decades, which has changed and will change the structure and function of ecosystems, and affects on ecosystem Carbon (C) cycle. As an important part in global C cycle, how the C cycle of tropical rainforests will be influenced by the N and P deposition should be focused on. This study simulated N and P deposition in a primary and secondary forest of tropical mountain rainforest in Jianfengling, Hainan, China, during five-year field experiment to evaluate the effects of N and P deposition on C cycling processes and relate characteristics. Six levels of N and P treatments were treated: Control, Low-N, Medium-N, High-N, P and N+P. The relative growth rates (RGR) of tree layer in treatment plots were different from that in control plots after years of N and P addition. Simulated N and P deposition also increased ANPP in primary forest. N and P addition changed the growth of trees by altering soil nutrient and microbial activities. N and P addition increased soil organic carbon (SOC) and total N (TN) content, and significantly increased soil total P (TP) content, not changing soil pH. During the whole process of N and P addition, as net nitrification rate and net N mineralization rate were promoted by N and P addition, and effective N content (nitrate) of soil increased in the plot treated with N treatments compared to the control treatment. The microbial P content was increased by N and P addition, and microbial N was not changed. The increasing N deposition may enhance soil nutrient and stimulate growth of trees, which will lead to an increase of the C sequestration.

  2. Nitrogen fixed by wheat plants as affected by nitrogen fertilizer levels and Non-symbiotic bacteria

    International Nuclear Information System (INIS)

    Inorganic nitrogen is required for all egyptian soils for wheat. Free living and N 2-fixing microorganisms are able associate closely related with the roots of geraminacae. Pot experiment studies were carried out to examine the response of wheat plants to inoculation with Azospirillum Brasilense and Azotobacter Chroococcum, single or in combination, under various levels of ammonium sulfate interaction between both the inoculants increased straw or grain yield as well as N-uptake by wheat plants with increasing N levels. Results showed that grains of wheat plants derived over 19,24 and 15% of its N content from the atmospheric - N 2 (Ndfa) with application of 25,50 and 75 mg N kg-1 soil in the presence of + Azospirillum + azotobacter. The final amount of N 2-fixers. The highest values of N 2-fixed were observed with mixed inoculants followed by inoculation with Azospirillum and then azotobacter. The recovery of applied ammonium sulfate-N was markedly increased by inoculation with combined inoculants, but less in uninoculated treatments. Seeds inoculated with non-symbiotic fixing bacteria could be saved about 25 kg N without much affecting the grain yield. i fig., 4 tabs

  3. Carbon and nitrogen additions induce distinct priming effects along an organic-matter decay continuum.

    Science.gov (United States)

    Qiao, Na; Xu, Xingliang; Hu, Yuehua; Blagodatskaya, Evgenia; Liu, Yongwen; Schaefer, Douglas; Kuzyakov, Yakov

    2016-01-01

    Decomposition of organic matter (OM) in soil, affecting carbon (C) cycling and climate feedbacks, depends on microbial activities driven by C and nitrogen (N) availability. However, it remains unknown how decomposition of various OMs vary across global supplies and ratios of C and N inputs. We examined OM decomposition by incubating four types of OM (leaf litter, wood, organic matter from organic and mineral horizons) from a decay continuum in a subtropical forest at Ailao Mountain, China with labile C and N additions. Decomposition of wood with high C:N decreased for 3.9 to 29% with these additions, while leaf decomposition was accelerated only within a narrow C:N range of added C and N. Decomposition of OM from organic horizon was accelerated by high C:N and suppressed by low C:N, but mineral soil was almost entirely controlled by high C:N. These divergent responses to C and N inputs show that mechanisms for priming (i.e. acceleration or retardation of OM decomposition by labile inputs) vary along this decay continuum. We conclude that besides C:N ratios of OM, those of labile inputs control the OM decay in the litter horizons, while energy (labile C) regulates decomposition in mineral soil. This suggests that OM decomposition can be predicted from its intrinsic C:N ratios and those of labile inputs. PMID:26806914

  4. Effects of Increased Summer Precipitation and Nitrogen Addition on Root Decomposition in a Temperate Desert.

    Directory of Open Access Journals (Sweden)

    Hongmei Zhao

    Full Text Available Climate change scenarios that include precipitation shifts and nitrogen (N deposition are impacting carbon (C budgets in arid ecosystems. Roots constitute an important part of the C cycle, but it is still unclear which factors control root mass loss and nutrient release in arid lands.Litterbags were used to investigate the decomposition rate and nutrient dynamics in root litter with water and N-addition treatments in the Gurbantunggut Desert in China. Water and N addition had no significant effect on root mass loss and the N and phosphorus content of litter residue. The loss of root litter and nutrient releases were strongly controlled by the initial lignin content and the lignin:N ratio, as evidenced by the negative correlations between decomposition rate and litter lignin content and the lignin:N ratio. Fine roots of Seriphidium santolinum (with higher initial lignin content had a slower decomposition rate in comparison to coarse roots.Results from this study indicate that small and temporary changes in rainfall and N deposition do not affect root decomposition patterns in the Gurbantunggut Desert. Root decomposition rates were significantly different between species, and also between fine and coarse roots, and were determined by carbon components, especially lignin content, suggesting that root litter quality may be the primary driver of belowground carbon turnover.

  5. Nitrogen fertilization affects silicon concentration, cell wall composition and biofuel potential of wheat straw

    DEFF Research Database (Denmark)

    Murozuka, Emiko; Laursen, Kristian Holst; Lindedam, Jane;

    2014-01-01

    at six different levels of nitrogen supply ranging from 48 to 288kg nitrogen ha-1 was analyzed for major cell wall components and mineral elements. Enzymatic digestion of the straw was carried out to evaluate the saccharification efficiency. The nitrogen concentration in the straw dry matter...... supplies. The enzymatic saccharification efficiency was negatively correlated with the rate of nitrogen supply. We conclude that the level of nitrogen supply to wheat plants alters the composition of cell wall components in the straw and that this may result in reduced saccharification efficiency. © 2014......Nitrogen is an essential input factor required for plant growth and biomass production. However, very limited information is available on how nitrogen fertilization affects the quality of crop residues to be used as lignocellulosic feedstock. In the present study, straw of winter wheat plants grown...

  6. Cabbage-head development as affected by nitrogen and temperature

    International Nuclear Information System (INIS)

    Cabbage plants were grown at graded levels of nitrate nitrogen (20 and 100 ppm N) and temperature (15, 20, and 250C, and the effects of these treatments on cabbage-head development were investigated. The total plant dry weight and the cabbage-head yield were always higher at 100 ppm N than at 20 ppm N, and at each N level the values were in the order of 20>15>250C. The nitrogen content in the outer leaves was higher at 100 ppm N than at 20 ppm N, and increased slightly with increase in temperature. The total sugar content was higher in the inner head leaves than in the outer leaves, and was decreased greatly at 250C in both organs. The 14CO2 assimilation of the outer leaves was larger at 100 ppm N than at 20 ppm N. After 14CO2 assimilation by the plants, a greater amount of 14C was lost by respiration at 250C than at 15 and 200C, resulting in a low distribution of 14C-sugars in the inner head leaves. The highest yield and a better quality of cabbage-heads were obtained when the plants were grown at 200C with a high N supply and the outer leaves had a carbohydrate/nitrogen content ratio of about 7. (author)

  7. Sediment diatom species and community response to nitrogen addition in Oregon (USA) estuarine tidal wetlands

    Science.gov (United States)

    Sediment microalgae play an important role in nutrient cycling and are important primary producers in the food web in Pacific Northwest estuaries. This study examines the effects of nitrogen addition to benthic microalgae in tidal wetlands of Yaquina Bay estuary on the Oregon c...

  8. The Impact of Long-Term Nitrogen Addition on Microbial Community Composition in Three Hawaiian Forest Soils

    Directory of Open Access Journals (Sweden)

    Teri C. Balser

    2001-01-01

    Full Text Available We evaluated the microbial communities in three Hawaiian forest soils along a natural fertility gradient and compared their distinct responses to long-term nitrogen (N additions. The sites studied have the same elevation, climate, and dominant vegetation, but vary in age of development, and thus in soil nutrient availability and nutrient limitation to plant growth. Fertilized plots at each site have received 100 kg ha year-1 N addition for at least 8 years. Soil parameters, water content, pH, and ammonium and nitrate availability differed by site, but not between control and N-addition treatments within a site at the time of sampling. Microbial biomass also varied by site, but was not affected by N addition. In contrast, microbial community composition (measured by phospholipid analysis varied among sites and between control and N-addition plots within a site. These data suggest that microbial community composition responds to N addition even when plant net primary productivity is limited by nutrients other than N. This may have implications for the behavior of forests impacted by atmospheric N deposition that are considered to be “nitrogen saturated,” yet still retain N in the soil.

  9. Effects of nitrogen and phosphorus additions on soil microbial biomass and community structure in two reforested tropical forests

    Science.gov (United States)

    Liu, Lei; Gundersen, Per; Zhang, Wei; Zhang, Tao; Chen, Hao; Mo, Jiangming

    2015-09-01

    Elevated nitrogen (N) deposition may aggravate phosphorus (P) deficiency in forests in the warm humid regions of China. To our knowledge, the interactive effects of long-term N deposition and P availability on soil microorganisms in tropical replanted forests remain unclear. We conducted an N and P manipulation experiment with four treatments: control, N addition (15 g N m-2·yr-1), P addition (15 g P m-2·yr-1), and N and P addition (15 + 15 g N and P m-2·yr-1, respectively) in disturbed (planted pine forest with recent harvests of understory vegetation and litter) and rehabilitated (planted with pine, but mixed with broadleaf returning by natural succession) forests in southern China. Nitrogen addition did not significantly affect soil microbial biomass, but significantly decreased the abundance of gram-negative bacteria PLFAs in both forest types. Microbial biomass increased significantly after P addition in the disturbed forest but not in the rehabilitated forest. No interactions between N and P additions on soil microorganisms were observed in either forest type. Our results suggest that microbial growth in replanted forests of southern China may be limited by P rather than by N, and this P limitation may be greater in disturbed forests.

  10. EFFECTS OF WATER TABLE AND NITROGEN ADDITION ON CO2 EMISSION FROM WETLAND SOIL

    Institute of Scientific and Technical Information of China (English)

    YANG Ji-song; LIU Jing-shuang; YU Jun-bao; WANG Jin-da; QIN Sheng-jin; LI Xin-hua

    2005-01-01

    Soil respiration is a main dynamic process of carbon cycle in wetland. It is important to contribute to global climate changes. Water table and nutritious availability are significant impact factors to influence responses of CO2 emission from wetland soil to climate changes. Twenty-four wetland soil monoliths at 4 water-table positions and in 3 nitrogen status have been incubated to measure rates of CO2 emission from wetland soils in this study.Three static water-table controls and a fluctuant water-table control, with 3 nitrogen additions in every water-table control,were carried out. In no nitrogen addition treatment, high CO2 emissions were found at a static low water table ( Ⅰ )and a fluctuant water table (Ⅳ),averaging 306.7mg/(m2·h) and 307.89mg/(m2·h), respectively, which were 51%-57% higher than that at static high water table ( Ⅱ and Ⅲ). After nitrogen addition, however, highest CO2 emission was found at Ⅱ and lowest emission at Ⅲ. The results suggested that nutritious availability of wetland soil might be important to influence the effect of water table on the CO2 emission from the wetland soil. Nitrogen addition led to enhancing CO2 emissions from wetland soil, while the highest emission was found in 1N treatments other than in 2N treatments. In 3 nutritious treatments,low CO2 emissions at high water tables and high CO2 emissions at low water tables were also observed when water table fluctuated. Our results suggested that both water table changes and nutritious imports would effect the CO2 emission from wetland.

  11. Intensified nitrogen removal in immobilized nitrifier enhanced constructed wetlands with external carbon addition.

    Science.gov (United States)

    Wang, Wei; Ding, Yi; Wang, Yuhui; Song, Xinshan; Ambrose, Richard F; Ullman, Jeffrey L

    2016-10-01

    Nitrogen removal performance response of twelve constructed wetlands (CWs) to immobilized nitrifier pellets and different influent COD/N ratios (chemical oxygen demand: total nitrogen in influent) were investigated via 7-month experiments. Nitrifier was immobilized on a carrier pellet containing 10% polyvinyl alcohol (PVA), 2.0% sodium alginate (SA) and 2.0% calcium chloride (CaCl2). A batch experiment demonstrated that 73% COD and 85% ammonia nitrogen (NH4-N) were degraded using the pellets with immobilized nitrifier cells. In addition, different carbon source supplement strategies were applied to remove the nitrate (NO3-N) transformed from NH4-N. An increase in COD/N ratio led to increasing reduction in NO3-N. Efficient nitrification and denitrification promoted total nitrogen (TN) removal in immobilized nitrifier biofortified constructed wetlands (INB-CWs). The results suggested that immobilized nitrifier pellets combined with high influent COD/N ratios could effectively improve the nitrogen removal performance in CWs. PMID:27396293

  12. Mechanisms and modeling of the effects of additives on the nitrogen oxides emission

    Science.gov (United States)

    Kundu, Krishna P.; Nguyen, Hung Lee; Kang, M. Paul

    1991-01-01

    A theoretical study on the emission of the oxides of nitrogen in the combustion of hydrocarbons is presented. The current understanding of the mechanisms and the rate parameters for gas phase reactions were used to calculate the NO(x) emission. The possible effects of different chemical species on thermal NO(x), on a long time scale were discussed. The mixing of these additives at various stages of combustion were considered and NO(x) concentrations were calculated; effects of temperatures were also considered. The chemicals such as hydrocarbons, H2, CH3OH, NH3, and other nitrogen species were chosen as additives in this discussion. Results of these calculations can be used to evaluate the effects of these additives on the NO(x) emission in the industrial combustion system.

  13. Effects of N2O and O2 addition to nitrogen Townsend dielectric barrier discharges at atmospheric pressure on the absolute ground-state atomic nitrogen density

    KAUST Repository

    Es-sebbar, Et-touhami

    2012-11-27

    Absolute ground-state density of nitrogen atoms N (2p3 4S3/2) in non-equilibrium Townsend dielectric barrier discharges (TDBDs) at atmospheric pressure sustained in N2/N2O and N2/O2 gas mixtures has been measured using Two-photon absorption laser-induced fluorescence (TALIF) spectroscopy. The quantitative measurements have been obtained by TALIF calibration using krypton as a reference gas. We previously reported that the maximum of N (2p3 4S3/2) atom density is around 3 × 1014 cm-3 in pure nitrogen TDBD, and that this maximum depends strongly on the mean energy dissipated in the gas. In the two gas mixtures studied here, results show that the absolute N (2p3 4S3/2) density is strongly affected by the N2O and O2 addition. Indeed, the density still increases exponentially with the energy dissipated in the gas but an increase in N2O and O2 amounts (a few hundreds of ppm) leads to a decrease in nitrogen atom density. No discrepancy in the order of magnitude of N (2p3 4S3/2) density is observed when comparing results obtained in N2/N2O and N2/O2 mixtures. Compared with pure nitrogen, for an energy of ∼90 mJ cm-3, the maximum of N (2p3 4S3/2) density drops by a factor of 3 when 100 ppm of N2O and O2 are added and it reduces by a factor of 5 for 200 ppm, to reach values close to our TALIF detection sensitivity for 400 ppm (1 × 1013 cm -3 at atmospheric pressure). © 2013 IOP Publishing Ltd.

  14. Fuzzy Control of Nitrate Recirculation and External Carbon Addition in A/O Nitrogen Removal Process

    Institute of Scientific and Technical Information of China (English)

    马勇; 彭永臻; 王淑莹; 王晓莲

    2005-01-01

    Nitrogen and phosphorous concentrations of effluent water must be taken into account for the design and operation of wastewater treatment plants. In addition, the requirement for effluent quality is becoming strict.Therefore, intelligent control approaches are recently required in removing biological nutrient. In this study, fuzzy control has been successfully applied to improve the nitrogen removal. Experimental results showed that a close relationship between nitrate concentration and oxidation-reduction potential (ORP) at the end of anoxic zone was found for anoxic/oxic (A/O) nitrogen removal process treating synthetic wastewater. ORP can be used as online fuzzy control parazneter of nitrate recirculation and external carbon addition. The established fuzzy logic controller that includes two inputs and one output can maintain ORP value at-86 mV and -90 mV by adjusting the nitrate recirculation flow and external carbon dosage respectively to realize the optimal control of nitrogen removal, improving the effluent quality and reducing the operating cost.

  15. Nitrogen and hydrophosphate affects glycolipids composition in microalgae

    Science.gov (United States)

    Wang, Xin; Shen, Zhouyuan; Miao, Xiaoling

    2016-01-01

    Glycolipids had received increasing attention because of their uses in various industries like cosmetics, pharmaceuticals, food and machinery manufacture. Microalgae were competitive organisms to accumulate metabolic substance. However, using microalgae to produce glycolipid was rare at present. In this study, glycolipid content of Chlorella pyrenoidosa and Synechococcus sp. under different nitrate and hydrophosphate levels were investigated. The highest glycolipid contents of 24.61% for C. pyrenoidosa and 15.37% for Synechococcus sp. were obtained at nitrate absence, which were 17.19% for C. pyrenoidosa and 10.99% for Synechococcus sp. at 0.01 and 0 g L−1 hydrophosphate, respectively. Glycolipid productivities of two microalgae could reach at more than 10.59 mg L−1 d−1. Nitrate absence induced at least 8.5% increase in MGDG, DGDG and SQDG, while hydrophosphate absence resulted in over 21.2% increase in DGDG and over 48.4% increase in SQDG and more than 22.2% decrease in MGDG in two microalgae. Simultaneous nitrate and hydrophosphate limitation could make further improvement of glycolipid accumulation, which was more than 25% for C. pyrenoidosa and 21% for Synechococcus sp. These results suggest that nitrogen and phosphorus limitation or starvation should be an efficient way to improve microalgal glycolipid accumulation. PMID:27440670

  16. Nitrogen and hydrophosphate affects glycolipids composition in microalgae.

    Science.gov (United States)

    Wang, Xin; Shen, Zhouyuan; Miao, Xiaoling

    2016-01-01

    Glycolipids had received increasing attention because of their uses in various industries like cosmetics, pharmaceuticals, food and machinery manufacture. Microalgae were competitive organisms to accumulate metabolic substance. However, using microalgae to produce glycolipid was rare at present. In this study, glycolipid content of Chlorella pyrenoidosa and Synechococcus sp. under different nitrate and hydrophosphate levels were investigated. The highest glycolipid contents of 24.61% for C. pyrenoidosa and 15.37% for Synechococcus sp. were obtained at nitrate absence, which were 17.19% for C. pyrenoidosa and 10.99% for Synechococcus sp. at 0.01 and 0 g L(-1) hydrophosphate, respectively. Glycolipid productivities of two microalgae could reach at more than 10.59 mg L(-1) d(-1). Nitrate absence induced at least 8.5% increase in MGDG, DGDG and SQDG, while hydrophosphate absence resulted in over 21.2% increase in DGDG and over 48.4% increase in SQDG and more than 22.2% decrease in MGDG in two microalgae. Simultaneous nitrate and hydrophosphate limitation could make further improvement of glycolipid accumulation, which was more than 25% for C. pyrenoidosa and 21% for Synechococcus sp. These results suggest that nitrogen and phosphorus limitation or starvation should be an efficient way to improve microalgal glycolipid accumulation. PMID:27440670

  17. Effect of nitrogen addition on the performance of microbial fuel cell anodes

    KAUST Repository

    Saito, Tomonori

    2011-01-01

    Carbon cloth anodes were modified with 4(N,N-dimethylamino)benzene diazonium tetrafluoroborate to increase nitrogen-containing functional groups at the anode surface in order to test whether the performance of microbial fuel cells (MFCs) could be improved by controllably modifying the anode surface chemistry. Anodes with the lowest extent of functionalization, based on a nitrogen/carbon ratio of 0.7 as measured by XPS, achieved the highest power density of 938mW/m2. This power density was 24% greater than an untreated anode, and similar to that obtained with an ammonia gas treatment previously shown to increase power. Increasing the nitrogen/carbon ratio to 3.8, however, decreased the power density to 707mW/m2. These results demonstrate that a small amount of nitrogen functionalization on the carbon cloth material is sufficient to enhance MFC performance, likely as a result of promoting bacterial adhesion to the surface without adversely affecting microbial viability or electron transfer to the surface. © 2010 Elsevier Ltd.

  18. The responses of soil respiration to nitrogen addition in a temperate grassland in northern China.

    Science.gov (United States)

    Luo, Qinpu; Gong, Jirui; Zhai, Zhanwei; Pan, Yan; Liu, Min; Xu, Sha; Wang, Yihui; Yang, Lili; Baoyin, Taoge-Tao

    2016-11-01

    Anthropogenic activities have increased nitrogen (N) inputs to grassland ecosystems. Knowledge of the impact of soil N availability on soil respiration (RS) is critical to understand soil carbon balances and their responses to global climate change. A 2-year field experiment was conducted to evaluate the response of RS to soil mineral N in a temperate grassland in northern China. RS, abiotic and biotic factors, and N mineralization were measured in the grassland, at rates of N addition ranging from 0 to 25gNm(-2)yr(-1). Annual and dormant-season RS ranged from 241.34 to 283.64g C m(-2) and from 61.34 to 83.84g C m(-2) respectively. High N application significantly increased RS, possibly due to increased root biomass and increased microbial biomass. High N treatment significantly increased soil NO3-N and inorganic N content compared with the control. The ratio of NO3-N to NH4-N and the N mineralization rate were significantly positively correlated with RS, but NH4-N was not correlated or negatively correlated with RS during the growing season. The temperature sensitivity of RS (Q10) was not significantly affected by N levels, and ranged from 1.90 to 2.20, but decreased marginally significantly at high N. RS outside the growing season is an important component of annual RS, accounting for 25.0 to 29.6% of the total. High N application indirectly stimulated RS by increasing soil NO3-N and net nitrification, thereby eliminating soil N limitations, promoting ecosystem productivity, and increasing soil CO2 efflux. Our results show the importance of distinguishing between NO3-N and NH4-N, as their impact on soil CO2 efflux differed. PMID:27396319

  19. OVARIAN HORMONE PRODUCTION AFFECTED BY AMYGDALIN ADDITION IN VITRO

    Directory of Open Access Journals (Sweden)

    Marek Halenár

    2015-02-01

    Full Text Available Amygdalin, a natural substance, is a cyanogenic glycoside occurring in the seeds of apricots and bitter almonds. It is a controversial anti-tumor compound that has been used as an alternative cancer drug for many years. Amygdalin is composed of two molecules of glucose, one of benzaldehyde, which induces an analgesic action, and one of hydrocyanic acid, which is an anti-neoplastic compound. This in vitro study was performed to evaluate the possible impact of amygdalin (1, 10, 100, 1000, 10 000 μg/mL on the secretory activity of granulosa cells (GCs from porcine cyclic ovaries. The release of progesterone and estradiol-17β by GCs were evaluated by ELISA. In our study, the noticeable changes in estradiol-17β release by ovarian GCs were determined after the amygdalin addition. Amygdalin, at the highest dose (10 000 μg/mL, significantly (P≤0.05 stimulated the release of estradiol-17β by GCs, in comparison to the untreated control cells. On the contrary, no significant (P≥0.05 changes in the progesterone release by GCs caused by amygdalin addition were observed. In conclusion, obtained results showed that the amygdalin application (various doses to ovarian GCs caused a dose-dependent stimulation of the estradiol-17β release, but not progesterone, and its possible modulatory impact on the steroid production in porcine ovaries.

  20. Decomposition of Different Litter Fractions in a Subtropical Bamboo Ecosystem as Affected by Experimental Nitrogen Deposition

    Institute of Scientific and Technical Information of China (English)

    TU Li-Hua; HU Hong-Ling; HU Ting-Xing; ZHANG Jian; LIU Li; LI Ren-Hong; DAI Hong-Zhong; LUO Shou-Hua

    2011-01-01

    As an important component of the global carbon (C) budget,litter decomposition in terrestrial ecosystems is greatly affected by the increasing nitrogen (N) deposition observed globally.We hypothesized that different litter fractions derived from a single tree species may respond to N deposition differently depending on the quality of the litter substrate.To test the hypothesis,a two-year field experiment was conducted using the litterbag method in a Pleioblastus amarus plantation in the rainy region of Southwest China.Four N treatment levels were applied:control (no N added),low-N (50 kg N ha-1 year-1),medium-N (150 kg N ha-1 year-1),and high-N (300 kg N ha-1 year-1).We observed different patterns of mass loss for the three P.amarus litter fractions (leaves,sheaths,and twigs) of varying substrate quality in the control plots.There were two decomposition stages with different decay rates (fast rate in early stages and slow rate in the later stages) for leaves and sheaths,while we did not observe a slower phase for the decay of twigs during the 2-year study period.The annual decomposition rate (k) of twigs was significantly lower than that of leaves or sheaths.Addition of N slowed the decomposition of leaves and twigs in the later stages of decomposition by inhibiting the decay of lignin and cellulose,while addition of N did not affect the mass loss of sheaths during the study period.In the decomposition of all three litter fractions,experimental N deposition reduced the net N accumulation in the early stages and also decreased the net N release in the later stages.The results of this study suggest that litter substrate quality may be an important factor affecting litter decomposition in a bamboo ecosystem affected by N deposition.

  1. Spatial variability of soil nitrogen in a hilly valley: Multiscale patterns and affecting factors.

    Science.gov (United States)

    Zhang, Shirong; Xia, Chunlan; Li, Ting; Wu, Chungui; Deng, Ouping; Zhong, Qinmei; Xu, Xiaoxun; Li, Yun; Jia, Yongxia

    2016-09-01

    Estimating the spatial distribution of soil nitrogen at different scales is crucial for improving soil nitrogen use efficiency and controlling nitrogen pollution. We evaluated the spatial variability of soil total nitrogen (TN) and available nitrogen (AN) in the Fujiang River Valley, a typical hilly region composed of low, medium and high hills in the central Sichuan Basin, China. We considered the two N forms at single hill, landscape and valley scales using a combined method of classical statistics, geostatistics and a geographic information system. The spatial patterns and grading areas of soil TN and AN were different among hill types and different scales. The percentages of higher grades of the two nitrogen forms decreased from low, medium to high hills. Hill type was a major factor determining the spatial variability of the two nitrogen forms across multiple scales in the valley. The main effects of general linear models indicated that the key affecting factors of soil TN and AN were hill type and fertilization at the single hill scale, hill type and soil type at the landscape scale, and hill type, slope position, parent material, soil type, land use and fertilization at the valley scale. Thus, the effects of these key factors on the two soil nitrogen forms became more significant with upscaling. PMID:27135562

  2. Effects of nitrogen and phosphorus additions on nitrous oxide emission in a nitrogen-rich and two nitrogen-limited tropical forests

    OpenAIRE

    Zheng, Mianhai; Zhang, Tao; Liu, Lei; Zhu, Weixing; Zhang, Wei; Mo, Jiangming

    2016-01-01

    Nitrogen (N) deposition is generally considered to increase soil nitrous oxide (N2O) emission in N-rich forests. In many tropical forests, however, elevated N deposition has caused soil N enrichment and further phosphorus (P) deficiency, and the interaction of N and P to control soil N2O emission remains poorly understood, particularly in forests with different soil N status. In this study, we examined the effects of N and P additions on soil N2O emission in an N-rich old-gr...

  3. The effect of nitrogen additions on oak foliage and herbivore communities at sites with high and low atmospheric pollution

    International Nuclear Information System (INIS)

    To evaluate plant and herbivore responses to nitrogen we conducted a fertilization study at a low and high pollution site in the mixed conifer forests surrounding Los Angeles, California. Contrary to expectations, discriminant function analysis of oak herbivore communities showed significant response to N fertilization when atmospheric deposition was high, but not when atmospheric deposition was low. We hypothesize that longer-term fertilization treatments are needed at the low pollution site before foliar N nutrition increases sufficiently to affect herbivore communities. At the high pollution site, fertilization was also associated with increased catkin production and higher densities of a byturid beetle that feeds on the catkins of oak. Leaf nitrogen and nitrate were significantly higher at the high pollution site compared to the low pollution site. Foliar nitrate concentrations were positively correlated with abundance of sucking insects, leafrollers and plutellids in all three years of the study. - Nitrogen additions at sites impacted by air pollution were associated with altered foliar herbivore communities and increased densities of a catkin-feeding beetle on Quercus kellogii

  4. Comparison of Nitrogen Fertilizers, Induce and Zinc Addition on Glyphosate Efficacy on Three Different Weed Species.

    OpenAIRE

    Hussein F. Abouziena; Ibraheem M. El-Metwally; H.M. El-Saeid; Megh Singh

    2014-01-01

    Herbicides are often tank-mixed with fertilizers to save time, labour, energy, and equipment costs. However addition of some additives with glyphosate may result in reducing glyphosate efficacy. Therefore we evaluated the potential of three nitrogen sources (ammonium sulphate (AMS) at 2 or 4% w/v, ammonium nitrate (AN) at 1 or 2% w/v, urea at 1 or 2 % w/v), nonionic adjuvant (Induce at 0.05% v/v) and Zn at 250 g Zn/ha (1321 ppm) to enhance glyphosate efficacy on pig weed (Amaranthus retroflex...

  5. Short-term nitrogen additions can shift a coastal wetland from a sink to a source of N2O

    Science.gov (United States)

    Moseman-Valtierra, S.; Gonzalez, R.; Kroeger, K.D.; Tang, J.; Chao, W.C.; Crusius, J.; Bratton, J.; Green, A.; Shelton, J.

    2011-01-01

    Coastal salt marshes sequester carbon at high rates relative to other ecosystems and emit relatively little methane particularly compared to freshwater wetlands. However, fluxes of all major greenhouse gases (N2O, CH4, and CO2) need to be quantified for accurate assessment of the climatic roles of these ecosystems. Anthropogenic nitrogen inputs (via run-off, atmospheric deposition, and wastewater) impact coastal marshes. To test the hypothesis that a pulse of nitrogen loading may increase greenhouse gas emissions from salt marsh sediments, we compared N2O, CH4 and respiratory CO2 fluxes from nitrate-enriched plots in a Spartina patens marsh (receiving single additions of NaNO3 equivalent to 1.4 g N m-2) to those from control plots (receiving only artificial seawater solutions) in three short-term experiments (July 2009, April 2010, and June 2010). In July 2009, we also compared N2O and CH4 fluxes in both opaque and transparent chambers to test the influence of light on gas flux measurements. Background fluxes of N2O in July 2009 averaged -33 ??mol N2O m-2 day-1. However, within 1 h of nutrient additions, N2O fluxes were significantly greater in plots receiving nitrate additions relative to controls in July 2009. Respiratory rates and CH4 fluxes were not significantly affected. N2O fluxes were significantly higher in dark than in transparent chambers, averaging 108 and 42 ??mol N2O m-2 day-1 respectively. After 2 days, when nutrient concentrations returned to background levels, none of the greenhouse gas fluxes differed from controls. In April 2010, N2O and CH4 fluxes were not significantly affected by nitrate, possibly due to higher nitrogen demands by growing S. patens plants, but in June 2010 trends of higher N2O fluxes were again found among nitrate-enriched plots, indicating that responses to nutrient pulses may be strongest during the summer. In terms of carbon equivalents, the highest average N2O and CH4 fluxes observed, exceeded half the magnitude of typical

  6. How inhibiting nitrification affects nitrogen cycle and reduces environmental impacts of anthropogenic nitrogen input

    Science.gov (United States)

    We conducted a meta-analysis of 103 nitrification inhibitor (NI) studies, and evaluated how NI application affects crop productivity and other ecosystem services in agricultural systems. Our results showed that, compared to conventional fertilizer practice, applications of NI alo...

  7. Exchangeable basic cations and nitrogen distribution in soil as affected by crop residues and nitrogen

    Directory of Open Access Journals (Sweden)

    Ciro Antonio Rosolem

    2011-06-01

    Full Text Available In this work, a greenhouse experiment was conducted to study the effects of N fertilization and residues of pearl millet, black oats and oilseed radish on pH and Ca, Mg, K, NO3-, and NH4+ distribution within the profile of a Distroferric Red Latosol. The equivalent of 8 t ha-1 of plant residues were placed on soil surface. Lime was applied on the soil surface and nitrogen was applied over the straw at 0, 50, 100, and 150 mg kg-1, as ammonium nitrate. Corn was grown for 57 days. Calcium contents and pH in the soil profile were decreased by Pearl millet residue, while black oat and oilseed radish increased Ca contents and these effects are not related with Ca contents in residue tissue. However, the presence of plant residues increased nitrate, ammonium, and potassium contents in the deeper layers of the pots.

  8. Linkages Between Biotic and Abiotic Belowground Processes in a Mojave Desert Ecosystem: Responses to Experimental Nitrogen and Water Additions

    Science.gov (United States)

    Verburg, P. S.; Marion, G. M.; Young, A. C.; Glanzmann, I.; Stevenson, B.; Arnone, J. A.; Nowak, R. S.

    2007-05-01

    Fine roots play a critical role in nutrient acquisition and water uptake. Yet it is unclear how fine roots in arid environments respond to increased nitrogen deposition and rainfall, two important global change factors in arid lands in the southwestern United States. In addition it is unclear how changes in root activity may impact soil CO2 concentrations, an important parameter affecting carbonate dynamics. We measured fine root length density (RLD) and soil CO2 concentrations for two years in experimentally manipulated plots in a Mojave Desert ecosystem. The study was conducted at the Mojave Global Change Facility located at the Nevada Test Site 60 miles northwest of Las Vegas. The treatments included: 1) three 25 mm water additions during the summer, 2) one nitrogen addition in the fall equivalent to 40 kg per hectare per year, 3) a combined water and nitrogen addition and, 4) untreated controls. Root data were collected using minirhizotron imaging approximately every 90 days underneath shrubs and intershrub areas. Soil CO2 concentrations were collected at the same sampling times and locations at 10, 40 and 90 cm depth using gas wells. The RLD showed clear seasonal patterns with the fastest increase in RLD occurring between February and April. During the winter the increase in RLD was higher underneath shrubs than in intershrub areas but during the summer months increases in RLD were similar under shrubs and in intershrub areas. Water additions slightly increased root mortality during the summer but this increase in mortality was not large enough to cause consistent differences in RLD between control and irrigated plots. Nitrogen addition had no effect on root dynamics in any of the plots. In contrast to RLD, irrigation consistently increased soil CO2 concentrations at all depths during the summer even when roots were not actively growing anymore. We speculate that the increased mortality under irrigation causes increased heterotrophic respiration which may

  9. Nitrogen addition, not initial phylogenetic diversity, increases litter decomposition by fungal communities

    Directory of Open Access Journals (Sweden)

    Anthony Stuart Amend

    2015-02-01

    Full Text Available Fungi play a critical role in the degradation of organic matter. Because different combinations of fungi result in different rates of decomposition, determining how climate change will affect microbial composition and function is fundamental to predicting future environments. Fungal response to global change is patterned by genetic relatedness, resulting in communities with comparatively low phylogenetic diversity. This may have important implications for the functional capacity of disturbed communities if lineages sensitive to disturbance also contain unique traits important for litter decomposition. Here we tested the relationship between phylogenetic diversity and decomposition rates. Leaf litter fungi were isolated from the field and deployed in microcosms as mock communities along a gradient of initial phylogenetic diversity, while species richness was held constant. Replicate communities were subject to nitrogen fertilization comparable to anthropogenic deposition levels. Carbon mineralization rates were measured over the course of sixty-six days. We found that nitrogen fertilization increased cumulative respiration by 24.8%, and that differences in respiration between fertilized and ambient communities diminished over the course of the experiment. Initial phylogenetic diversity failed to predict respiration rates or their change in response to nitrogen fertilization, and there was no correlation between community similarity and respiration rates. Last, we detected no phylogenetic signal in the contributions of individual isolates to respiration rates. Our results suggest that the degree to which phylogenetic diversity predicts ecosystem function will depend on environmental context.

  10. Fatty acid composition of camelina sativa as affected by combined nitrogen and sulphur fertilisation

    OpenAIRE

    Šípalová, Markéta; Lošák, Tomáš; Hlušek, Jaroslav; Vollmann, Johann; Hudec, Jozef; Filipčík, Radek; Macek, Michal; Kráčmar, Stanislav

    2011-01-01

    Camelina (false flax) oil is an important source of linolenic acid (C18:3). As agronomic treatments such as fertilization may affect seed quality parameters in oilseeds, fatty acid composition and oil content of Camelina sativa were investigated as affected by the combined application of nitrogen and sulphur in pot experiments. Nitrogen was applied as NH4NO3 at rates of 0.6 (N1), 0.9 (N2) or 1.2 (N3) g per pot. To increase the natural soil S-SO42- level of 25 mg/kg (S0) to 35 mg/kg (S1), 45 m...

  11. Decomposition of conifer tree bark under field conditions: effects of nitrogen and phosphorus additions

    Science.gov (United States)

    Lopes de Gerenyu, Valentin; Kurganova, Irina; Kapitsa, Ekaterina; Shorokhova, Ekaterina

    2016-04-01

    In forest ecosystems, the processes of decomposition of coarse woody debris (CWD) can contribute significantly to the emission component of carbon (C) cycle and thus accelerate the greenhouse effect and global climate change. A better understanding of decomposition of CWD is required to refine estimates of the C balance in forest ecosystems and improve biogeochemical models. These estimates will in turn contribute to assessing the role of forests in maintaining their long-term productivity and other ecosystems services. We examined the decomposition rate of coniferous bark with added nitrogen (N) and phosphorus (P) fertilizers in experiment under field conditions. The experiment was carried out in 2015 during 17 weeks in Moscow region (54o50'N, 37o36'E) under continental-temperate climatic conditions. The conifer tree bark mixture (ca. 70% of Norway spruce and 30% of Scots pine) was combined with soil and placed in piles of soil-bark substrate (SBS) with height of ca. 60 cm and surface area of ca. 3 m2. The dry mass ratio of bark to soil was 10:1. The experimental design included following treatments: (1) soil (Luvisols Haplic) without bark, (S), (2) pure SBS, (3) SBS with N addition in the amount of 1% of total dry bark mass (SBS-N), and (4) SBS with N and P addition in the amount of 1% of total dry bark mass for each element (SBS-NP). The decomposition rate expressed as CO2 emission flux, g C/m2/h was measured using closed chamber method 1-3 times per week from July to early November using LiCor 6400 (Nebraska, USA). During the experiment, we also controlled soil temperature at depths of 5, 20, 40, and 60 cm below surface of SBS using thermochrons iButton (DS1921G, USA). The pattern of CO2 emission rate from SBS depended strongly on fertilizing. The highest decomposition rates (DecR) of 2.8-5.6 g C/m2/h were observed in SBS-NP treatment during the first 6 weeks of experiment. The decay process of bark was less active in the treatment with only N addition. In this

  12. The effect of oxygen and nitrogen additives on the growth of nanocrystalline diamond films

    International Nuclear Information System (INIS)

    Nanocrystalline diamond (NCD) films have been synthesized by using either nitrogen addition or oxygen addition to conventional CH4/H2 mixtures besides the most commonly used Ar/CH4 with or without H2 chemistry. However, the synthesis of NCD films using both nitrogen and oxygen addition simultaneously into CH4/H2 gases has not been reported thus far. In this work, we investigate the effect of simultaneous O2 and N2 addition to CH4/H2 plasma on the growth of nanocrystalline diamond (NCD) films, focusing particularly on the ratio between the amount of O2 and N2 additives into conventional CH4/H2 gas mixtures on the morphology, microstructure, texture, and crystalline quality of the NCD films. The NCD samples were produced by using a high microwave power (3 kW) in a microwave plasma-assisted chemical vapour deposition reactor with a maximum power of 5 kW on large silicon wafers, 2 inches in diameter, and characterized by high-resolution scanning electron microscopy, x-ray diffraction and micro-Raman spectroscopy. Our work demonstrates that, under the conditions investigated here, NCD films can be formed when the ratio of O2/N2 addition is increased from 0 through 1 up to 7/3 (at higher than 7/3, for example 4, a large-grained polycrystalline diamond film will form), and the crystalline quality is significantly enhanced with the increase of oxygen addition. The mechanism of O2 and N2 additives on the formation of NCD films is briefly studied

  13. Autotrophic nitrogen removal from black water: calcium addition as a requirement for settleability.

    Science.gov (United States)

    de Graaff, M S; Temmink, H; Zeeman, G; van Loosdrecht, M C M; Buisman, C J N

    2011-01-01

    Black (toilet) water contains half of the organic load in the domestic wastewater, as well as the major fraction of the nutrients nitrogen and phosphorus. When collected with vacuum toilets, the black water is 25 times more concentrated than the total domestic wastewater stream, i.e. including grey water produced by laundry, showers etc. A two-stage nitritation-anammox process was successfully employed and removed 85%-89% of total nitrogen in anaerobically treated black water. The (free) calcium concentration in black water was too low (42 mg/L) to obtain sufficient granulation of anammox biomass. The granulation and retention of the biomass was improved considerably by the addition of 39 mg/L of extra calcium. This resulted in a volumetric nitrogen removal rate of 0.5 gN/L/d, irrespective of the two temperatures of 35 °C and 25 °C at which the anammox reactors were operated. Nitrous oxide, a very strong global warming gas, was produced in situations of an incomplete anammox conversion accompanied by elevated levels of nitrite. PMID:20822793

  14. Arbuscular mycorrhizal fungal community response to warming and nitrogen addition in a semiarid steppe ecosystem.

    Science.gov (United States)

    Kim, Yong-Chan; Gao, Cheng; Zheng, Yong; He, Xin-Hua; Yang, Wei; Chen, Liang; Wan, Shi-Qiang; Guo, Liang-Dong

    2015-05-01

    Understanding the response of arbuscular mycorrhizal (AM) fungi to warming and nitrogen (N) fertilization is critical to assess the impact of anthropogenic disturbance on ecosystem functioning under global climate change scenarios. In this study, AM fungal communities were examined in a full factorial design with warming and N addition in a semiarid steppe in northern China. Warming significantly increased AM fungal spore density, regardless of N addition, whilst N addition significantly decreased AM fungal extraradical hyphal density, regardless of warming. A total of 79 operational taxonomic units (OTUs) of AM fungi were recovered by 454 pyrosequencing of SSU rDNA. Warming, but not N addition, had a significant positive effect on AM fungal OTU richness, while warming and N addition significantly increased AM fungal Shannon diversity index. N addition, but not warming, significantly altered the AM fungal community composition. Furthermore, the changes in AM fungal community composition were associated with shifts in plant community composition indirectly caused by N addition. These findings highlight the different effects of warming and N addition on AM fungal communities and contribute to understanding AM fungal community responses to global environmental change scenarios in semiarid steppe ecosystems. PMID:25307533

  15. Soil N2O fluxes along an elevation gradient of tropical montane forests under experimental nitrogen and phosphorus addition

    Science.gov (United States)

    Müller, Anke; Matson, Amanda; Corre, Marife; Veldkamp, Edzo

    2015-10-01

    Nutrient deposition to tropical forests is increasing, which could affect soil fluxes of nitrous oxide (N2O), a powerful greenhouse gas. We assessed the effects of 35-56 months of moderate nitrogen (N) and phosphorus (P) additions on soil N2O fluxes and net soil N-cycling rates, and quantified the relative contributions of nitrification and denitrification to N2O fluxes. In 2008, a nutrient manipulation experiment was established along an elevation gradient (1000, 2000 and 3000 m) of montane forests in southern Ecuador. Treatments included control, N, P and N+P addition (with additions of 50 kg N ha-1 yr-1 and 10 kg P ha-1 yr-1). Nitrous oxide fluxes were measured using static, vented chambers and N cycling was determined using the buried bag method. Measurements showed that denitrification was the main N2O source at all elevations, but that annual N2O emissions from control plots were low, and decreased along the elevation gradient (0.57 ± 0.26 to 0.05 ± 0.04 kg N2O-N ha-1 yr-1). We attributed the low fluxes to our sites’ conservative soil N cycling as well as gaseous N losses possibly being dominated by N2. Contrary to the first 21 months of the experiment, N addition did not affect N2O fluxes during the 35-56 month period, possibly due to low soil moisture contents during this time. With P addition, N2O fluxes and mineral N concentrations decreased during Months 35-56, presumably because plant P limitations were alleviated, increasing plant N uptake. Nitrogen plus phosphorus addition showed similar trends to N addition, but less pronounced given the counteracting effects of P addition. The combined results from this study (Months 1-21 and 35-56) showed that effects of N and P addition on soil N2O fluxes were not linear with time of exposure, highlighting the importance of long-term studies.

  16. Does nitrogen gas bubbled through a low density polymer gel dosimeter solution affect the polymerization process?

    Directory of Open Access Journals (Sweden)

    Daryoush Shahbazi-Gahrouei

    2015-01-01

    Conclusion: It appeared that reactions between gelatin-free radicals and monomers, due to an increase in the gel temperature during rotation in the household mixer, led to a higher R 2 -background response. In the second type of gel, it seemed that the collapse of the nitrogen bubbles was the main factor that affected the R 2 -responses.

  17. Carbon dynamics in subtropical forest soil. Effects of atmospheric carbon dioxide enrichment and nitrogen addition

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Juxiu X.; Zhou, Guoyi Y.; Zhang, Deqiang Q.; Duan, Honglang L.; Deng, Qi; Zhao, Liang [Chinese Academy of Sciences, Guangzhou (China). South China Botanical Garden; Xu, Zhihong H. [Griffith Univ., Nathan, Queensland (Australia). Environmental Futures Centre and School of Biomolecular and Physical Sciences

    2010-06-15

    The levels of atmospheric carbon dioxide concentration ([CO{sub 2}]) are rapidly increasing. Understanding carbon (C) dynamics in soil is important for assessing the soil C sequestration potential under elevated [CO{sub 2}]. Nitrogen (N) is often regarded as a limiting factor in the soil C sequestration under future CO{sub 2} enrichment environment. However, few studies have been carried out to examine what would happen in the subtropical or tropical areas where the ambient N deposition is high. In this study, we used open-top chambers to study the effect of elevated atmospheric [CO{sub 2}] alone and together with N addition on the soil C dynamics in the first 4 years of the treatments applied in southern China. Materials and methods Above- and below-ground C input (tree biomass) into soil, soil respiration, soil organic C, and total N as well as dissolved organic C (DOC) were measured periodically in each of the open-top chambers. Soil samples were collected randomly in each chamber from each of the soil layers (0-20, 20-40, and 40-60 cm) using a standard soil sampling tube (2.5-cm inside diameter). Soil leachates were collected at the bottom of the chamber below-ground walls in stainless steel boxes. Results and discussion The highest above- and below-ground C input into soil was found in the high CO{sub 2} and high N treatment (CN), followed by the only high N treatment (N+), the only high CO{sub 2} treatment (C+), and then the control (CK) without any CO{sub 2} enrichment or N addition. DOC in the leachates was small for all the treatments. Export of DOC played a minor role in C cycling in our experiment. Generally, soil respiration rate in the chambers followed the order: CN treatment > C + treatment > N + treatment > the control. Except for the C+ treatment, there were no significant differences in soil total N among the CN treatment, N + treatment, and the control. Overall, soil organic C (SOC) was significantly affected by the treatments (p < 0.0001). SOC

  18. Dynamics of Litter Decomposition, Microbiota Populations, and Nutrient Movement Following Nitrogen and Phosphorus Additions to a Deciduous Forest Stand

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, J.M.

    2002-10-29

    The objective of this study was quantification of the dynamics of litter decomposition, microbiota populations, and nutrient movement in response to nitrogen and phosphorus additions to a deciduous forest stand. Nitrogen (urea) was applied at rates of 0, 550, and 1100 kg/ha in combination with phosphorus (concentrated superphosphate) at rates of 0, 275, and 550 kg/ha. Total loss of organic material from white oak, red maple, and black gum litter bags over a 16-month period was 34, 35, and 45%, respectively. Phosphorus treatment retarded weight loss from litter bags of all species. Weight loss for the 0-, 275-, and 55-kg/ha levels of phosphorus averaged 23, 20, and 19% for white oak; 26, 25, and 25% for red maple; 29, 27 and 26% for black gum. Weight losses were increased by a small amount (1 to 2%) or not at all by nitrogen treatment. The NP interfaction weight loss means were intermediate to the main treatment means. The increase in decomposition associated with nitrogen was offset by the decrease associated with phosphorus. Litter and soil bacterial populations were significantly increased by nitrogen additions, while litter and soil fungi did not respond to nitrogen. Soil fungal populations were increased by phosphorus addition, while litter bacterial populations were reduced. Litter fungi and soil bacteria did not respond to phosphorus. Combined additions of nitrogen and phosphorus increased bacterial populations, though not as much as nitrogen alone. There was a good correlation (r = 0.70) between bacterial population and litter weight loss.

  19. Effect of Addition of Nitrogen to a Capacitively Radio-Frequency Hydrogen Discharge

    International Nuclear Information System (INIS)

    A hybrid PIC/MC model is developed in this work for H2-xN2 capacitively coupled radio-frequency (CCRF) discharges in which we take into account 43 kinds of collisions reaction processes between charged particles (e−, H+3, H+2, H+, N+2, N+) and ground-state molecules (H2, N2). In addition, the mean energies and densities of electrons and ions (H+3, H+2, H+), and electric field distributions in the H2-N2 CCRF discharge are simulated by this model. Furthermore, the effects of addition of a variable percentage of nitrogen (0–30%) into the H2 discharge on the plasma processes and discharge characteristics are studied. It is shown that by increasing the percentage of nitrogen added to the system, the RF sheath thickness will narrow, the sheath electric field will be enhanced, and the mean energy of hydrogen ions impacting the electrodes will be increased. Because the electron impact ionization and dissociative ionization rates increase when N2 is added to the system, the electron mean density will increase while the electron mean energy and hydrogen ion density near the electrodes will decrease. This work aims to provide a theoretical basis for experimental studies and technological developments with regard to H2-N2 CCRF plasmas

  20. Stimulation of terrestrial ecosystem carbon storage by nitrogen addition: a meta-analysis.

    Science.gov (United States)

    Yue, Kai; Peng, Yan; Peng, Changhui; Yang, Wanqin; Peng, Xin; Wu, Fuzhong

    2016-01-01

    Elevated nitrogen (N) deposition alters the terrestrial carbon (C) cycle, which is likely to feed back to further climate change. However, how the overall terrestrial ecosystem C pools and fluxes respond to N addition remains unclear. By synthesizing data from multiple terrestrial ecosystems, we quantified the response of C pools and fluxes to experimental N addition using a comprehensive meta-analysis method. Our results showed that N addition significantly stimulated soil total C storage by 5.82% ([2.47%, 9.27%], 95% CI, the same below) and increased the C contents of the above- and below-ground parts of plants by 25.65% [11.07%, 42.12%] and 15.93% [6.80%, 25.85%], respectively. Furthermore, N addition significantly increased aboveground net primary production by 52.38% [40.58%, 65.19%] and litterfall by 14.67% [9.24%, 20.38%] at a global scale. However, the C influx from the plant litter to the soil through litter decomposition and the efflux from the soil due to microbial respiration and soil respiration showed insignificant responses to N addition. Overall, our meta-analysis suggested that N addition will increase soil C storage and plant C in both above- and below-ground parts, indicating that terrestrial ecosystems might act to strengthen as a C sink under increasing N deposition. PMID:26813078

  1. Stimulation of terrestrial ecosystem carbon storage by nitrogen addition: a meta-analysis

    Science.gov (United States)

    Yue, Kai; Peng, Yan; Peng, Changhui; Yang, Wanqin; Peng, Xin; Wu, Fuzhong

    2016-01-01

    Elevated nitrogen (N) deposition alters the terrestrial carbon (C) cycle, which is likely to feed back to further climate change. However, how the overall terrestrial ecosystem C pools and fluxes respond to N addition remains unclear. By synthesizing data from multiple terrestrial ecosystems, we quantified the response of C pools and fluxes to experimental N addition using a comprehensive meta-analysis method. Our results showed that N addition significantly stimulated soil total C storage by 5.82% ([2.47%, 9.27%], 95% CI, the same below) and increased the C contents of the above- and below-ground parts of plants by 25.65% [11.07%, 42.12%] and 15.93% [6.80%, 25.85%], respectively. Furthermore, N addition significantly increased aboveground net primary production by 52.38% [40.58%, 65.19%] and litterfall by 14.67% [9.24%, 20.38%] at a global scale. However, the C influx from the plant litter to the soil through litter decomposition and the efflux from the soil due to microbial respiration and soil respiration showed insignificant responses to N addition. Overall, our meta-analysis suggested that N addition will increase soil C storage and plant C in both above- and below-ground parts, indicating that terrestrial ecosystems might act to strengthen as a C sink under increasing N deposition.

  2. Modeling uncertainties for tropospheric nitrogen dioxide columns affecting satellite-based inverse modeling of nitrogen oxides emissions

    Directory of Open Access Journals (Sweden)

    J.-T. Lin

    2012-12-01

    Full Text Available Errors in chemical transport models (CTMs interpreting the relation between space-retrieved tropospheric column densities of nitrogen dioxide (NO2 and emissions of nitrogen oxides (NOx have important consequences on the inverse modeling. They are however difficult to quantify due to lack of adequate in situ measurements, particularly over China and other developing countries. This study proposes an alternate approach for model evaluation over East China, by analyzing the sensitivity of modeled NO2 columns to errors in meteorological and chemical parameters/processes important to the nitrogen abundance. As a demonstration, it evaluates the nested version of GEOS-Chem driven by the GEOS-5 meteorology and the INTEX-B anthropogenic emissions and used with retrievals from the Ozone Monitoring Instrument (OMI to constrain emissions of NOx. The CTM has been used extensively for such applications. Errors are examined for a comprehensive set of meteorological and chemical parameters using measurements and/or uncertainty analysis based on current knowledge. Results are exploited then for sensitivity simulations perturbing the respective parameters, as the basis of the following post-model linearized and localized first-order modification. It is found that the model meteorology likely contains errors of various magnitudes in cloud optical depth, air temperature, water vapor, boundary layer height and many other parameters. Model errors also exist in gaseous and heterogeneous reactions, aerosol optical properties and emissions of non-nitrogen species affecting the nitrogen chemistry. Modifications accounting for quantified errors in 10 selected parameters increase the NO2 columns in most areas with an average positive impact of 18% in July and 8% in January, the most important factor being modified uptake of the hydroperoxyl radical (HO2 on aerosols. This suggests a possible systematic model

  3. Biochar Addition to Stormwater Treatment Media for Enhanced Removal of Nitrogen

    Science.gov (United States)

    Imhoff, P. T.; Jin, J.; Tian, J.; Chiu, P.; Guo, M.

    2015-12-01

    Urban stormwater management systems, such as bioretention facilities, require substantial land area and are often ineffective in removing nitrogen. This project seeks to improve nitrogen removal in bioretention media by modifying the hydraulic and treatment characteristics of the infiltration medium with biochar addition. A commercial wood biochar pyrolyzed from Southern Yellow Pine at 500°C was used. Laboratory experiments demonstrated that biochar addition to a typical bioretention medium (soil-mix: 4% saw dust, 88% sand, 8% clay) increased ammonium sorption at typical stormwater concentrations (2 mg/L) by a factor of 6, total porosity by 16.6%, and water retention at most matric potentials. The effect of the biochar-amended medium on nitrate removal was evaluated in pilot-scale experiments. Side-by-side experimental cells (91 cm dia., 1.2 m deep) were constructed to treat stormwater runoff from a parking lot. The control cell contained 100% soil mix while the biochar cell contained 4% biochar and 96% soil-mix by mass. Treatment media were 76.2 cm in depth and overlain by 5.1 cm of wood mulch in both cells, with a water table maintained at the bottom of the treatment zones. Cells were instrumented with TDR moisture sensors, pressure transducers, and redox and temperature sensors. Two pilot-scale experiments were conducted that included a bromide tracer and nitrate with a hydraulic loading of 5.5cm/h for 24 h in early spring and 36 h in summer. Effluent was continuously sampled for nitrogen compounds during these tests. Tracer tests and TDR measurements showed that biochar increased the average volumetric water content of the vadose zone by 14.7% and the mean residence time by 12.6%. For the spring field test at 14°C, nitrate in the control cell effluent increased by 6.1% but decreased by 43.5% for the biochar cell. For the summer field test at 22°C, 30.6% and 84.7% of influent nitrate was removed in the control and biochar cells, respectively. In the summer

  4. Soil physical and hydrological properties as affected by long-term addition of various organic amendments

    Science.gov (United States)

    Eden, Marie; Völkel, Jörg; Mercier, Vincent; Labat, Christophe; Houot, Sabine

    2014-05-01

    The use of organic residues as soil amendments in agriculture not only reduces the amount of waste needing to be disposed of; it may also lead to improvements in soil properties, including physical and hydrological ones. The present study examines a long-term experiment called "Qualiagro", run jointly by INRA and Veolia Environment in Feucherolles, France (near Paris). It was initiated in 1998 on a loess-derived silt loam (787 g/kg silt, 152 g/kg clay) and includes ten treatments: four types of organic amendments and a control (CNT) each at two levels of mineral nitrogen (N) addition: minimal (Nmin) and optimal (Nopt). The amendments include three types of compost and farmyard manure (FYM), which were applied every other year at a rate of ca. 4 t carbon ha-1. The composts include municipal solid waste compost (MSW), co-compost of green wastes and sewage sludge (GWS), and biowaste compost (BIO). The plots are arranged in a randomized block design and have a size of 450 m²; each treatment is replicated four times (total of 40 plots). Ca. 15 years after the start of the experiment soil organic carbon (OC) had continuously increased in the amended plots, while it remained stable or decreased in the control plots. This compost- or manure-induced increase in OC plays a key role, affecting numerous dependant soil properties like bulk density, porosity and water retention. The water holding capacity (WHC) of a soil is of particular interest to farmers in terms of water supply for plants, but also indicates soil quality and functionality. Addition of OC may affect WHC in different ways: carbon-induced aggregation may increase larger-pore volume and hence WHC at the wet end while increased surface areas may lead to an increased retention of water at the dry end. Consequently it is difficult to predict (e.g. with pedotransfer functions) the impact on the amount of water available for plants (PAW), which was experimentally determined for the soils, along with the entire range

  5. Ammonia-oxidizing archaea respond positively to inorganic nitrogen addition in desert soils.

    Science.gov (United States)

    Marusenko, Yevgeniy; Garcia-Pichel, Ferran; Hall, Sharon J

    2015-02-01

    In soils, nitrogen (N) addition typically enhances ammonia oxidation (AO) rates and increases the population density of ammonia-oxidizing bacteria (AOB), but not that of ammonia-oxidizing archaea (AOA). We asked if long-term inorganic N addition also has similar consequences in arid land soils, an understudied yet spatially ubiquitous ecosystem type. Using Sonoran Desert top soils from between and under shrubs within a long-term N-enrichment experiment, we determined community concentration-response kinetics of AO and measured the total and relative abundance of AOA and AOB based on amoA gene abundance. As expected, N addition increased maximum AO rates and the abundance of bacterial amoA genes compared to the controls. Surprisingly, N addition also increased the abundance of archaeal amoA genes. We did not detect any major effects of N addition on ammonia-oxidizing community composition. The ammonia-oxidizing communities in these desert soils were dominated by AOA as expected (78% of amoA gene copies were related to Nitrososphaera), but contained unusually high contributions of Nitrosomonas (18%) and unusually low numbers of Nitrosospira (2%). This study highlights unique traits of ammonia oxidizers in arid lands, which should be considered globally in predictions of AO responses to changes in N availability. PMID:25764551

  6. Tailoring of structure formation and phase composition in reactively sputtered zirconium oxide films using nitrogen as an additional reactive gas

    OpenAIRE

    Severin, D.; Sarakinos, Kostas; Kappertz, O.; Pflug, A; Wuttig, M.

    2008-01-01

    The structure of ZrO(2) films has been controlled during reactive sputtering in an argon/oxygen atmosphere by adding an amount of nitrogen gas to the process. Depending on the deposition conditions, amorphous, cubic, or monoclinic films have been obtained without any additional substrate heating. The resulting film structure is explained in terms of the control of fast negative oxygen ions generated at the target surface and accelerated toward the growing film. Furthermore, the nitrogen addit...

  7. Effects of nitrogen and phosphorus additions on nitrous oxide emission in a nitrogen-rich and two nitrogen-limited tropical forests

    Science.gov (United States)

    Zheng, Mianhai; Zhang, Tao; Liu, Lei; Zhu, Weixing; Zhang, Wei; Mo, Jiangming

    2016-06-01

    Nitrogen (N) deposition is generally considered to increase soil nitrous oxide (N2O) emission in N-rich forests. In many tropical forests, however, elevated N deposition has caused soil N enrichment and further phosphorus (P) deficiency, and the interaction of N and P to control soil N2O emission remains poorly understood, particularly in forests with different soil N status. In this study, we examined the effects of N and P additions on soil N2O emission in an N-rich old-growth forest and two N-limited younger forests (a mixed and a pine forest) in southern China to test the following hypotheses: (1) soil N2O emission is the highest in old-growth forest due to the N-rich soil; (2) N addition increases N2O emission more in the old-growth forest than in the two younger forests; (3) P addition decreases N2O emission more in the old-growth forest than in the two younger forests; and (4) P addition alleviates the stimulation of N2O emission by N addition. The following four treatments were established in each forest: Control, N addition (150 kg N ha-1 yr-1), P addition (150 kg P ha-1 yr-1), and NP addition (150 kg N ha-1 yr-1 plus 150 kg P ha-1 yr-1). From February 2007 to October 2009, monthly quantification of soil N2O emission was performed using static chamber and gas chromatography techniques. Mean N2O emission was shown to be significantly higher in the old-growth forest (13.9 ± 0.7 µg N2O-N m-2 h-1) than in the mixed (9.9 ± 0.4 µg N2O-N m-2 h-1) or pine (10.8 ± 0.5 µg N2O-N m-2 h-1) forests, with no significant difference between the latter two. N addition significantly increased N2O emission in the old-growth forest but not in the two younger forests. However, both P and NP addition had no significant effect on N2O emission in all three forests, suggesting that P addition alleviated the stimulation of N2O emission by N addition in the old-growth forest. Although P fertilization may alleviate the stimulated effects of atmospheric N deposition on N2O

  8. Nitrogen Addition Altered the Effect of Belowground C Allocation on Soil Respiration in a Subtropical Forest.

    Science.gov (United States)

    He, Tongxin; Wang, Qingkui; Wang, Silong; Zhang, Fangyue

    2016-01-01

    The availabilities of carbon (C) and nitrogen (N) in soil play an important role in soil carbon dioxide (CO2) emission. However, the variation in the soil respiration (Rs) and response of microbial community to the combined changes in belowground C and N inputs in forest ecosystems are not yet fully understood. Stem girdling and N addition were performed in this study to evaluate the effects of C supply and N availability on Rs and soil microbial community in a subtropical forest. The trees were girdled on 1 July 2012. Rs was monitored from July 2012 to November 2013, and soil microbial community composition was also examined by phospholipid fatty acids (PLFAs) 1 year after girdling. Results showed that Rs decreased by 40.5% with girdling alone, but N addition only did not change Rs. Interestingly, Rs decreased by 62.7% under the girdling with N addition treatment. The reducing effect of girdling and N addition on Rs differed between dormant and growing seasons. Girdling alone reduced Rs by 33.9% in the dormant season and 54.8% in the growing season compared with the control. By contrast, girdling with N addition decreased Rs by 59.5% in the dormant season and 65.4% in the growing season. Girdling and N addition significantly decreased the total and bacterial PLFAs. Moreover, the effect of N addition was greater than girdling. Both girdling and N addition treatments separated the microbial groups on the basis of the first principal component through principal component analysis compared with control. This indicated that girdling and N addition changed the soil microbial community composition. However, the effect of girdling with N addition treatment separated the microbial groups on the basis of the second principal component compared to N addition treatment, which suggested N addition altered the effect of girdling on soil microbial community composition. These results suggest that the increase in soil N availability by N deposition alters the effect of

  9. Attempts to improve nitrogen utilization efficiency of aquaponics through nitrifies addition and filler gradation.

    Science.gov (United States)

    Zou, Yina; Hu, Zhen; Zhang, Jian; Xie, Huijun; Liang, Shuang; Wang, Jinhe; Yan, Runxin

    2016-04-01

    Aquaponics has attracted worldwide attention in recent years and is considered as an alternative technology for conventional aquaculture. In this study, common carp (Cyprinus carpio) and pakchoi (Brassica chinensis) were cultured in lab-scale aquaponics, and attempts were conducted to enhance its nitrogen utilization efficiency (NUE) through two optimization methods, i.e., nitrifies addition (NA) and filler gradation (FG). Results showed that NA and FG could improve the NUE of aquaponics by 8.8 and 16.0%, respectively, compared with control. The total ammonia (TAN) and nitrite (NO2(-)) concentrations in NA and FG systems were maintained at relatively low level (TAN aquaponics also contributed to global warming. Although the two proposed attempts in this study caused more N2O emission, they made new breakthrough in improving the NUE of aquaponics. PMID:26645232

  10. Yield and Nitrogen Assimilation of Potato Varieties (Solanum tuberosum L.) as Affected by Saline Water Irrigation and Organic Manure

    International Nuclear Information System (INIS)

    The experiment was carried out in lysimeter under controlled greenhouse conditions. Saline water was applied in different levels, i.e. fresh water, 3 and 6 dS/m. Organic manure were applied to soil at rates of 0, 2.6 and 5.2 kg/m2. Basal recommended doses of P and K were applied. Labelled urea (10% a.e.) was applied at rate of 200 kg N/ha. 15N technique was used to evaluate N-uptake and fertilizer efficiency. Comparison held between the two potato varieties indicated that higher reduction in shoot dry weight was recorded with Nicola variety than Spunta one which irrigated with 6 dS/m water salinity level. Addition of 2.6 kg/m2 organic rate induced an increase in N uptake with fresh water and 3 dS/m salinity then tended to decrease with 6 dS/m level as compared to the untreated control. Concerning the nitrogen fertilization, data of 15N analysis showed that, water salinity levels combined with organic addition rates were frequently affected the nitrogen derived from fertilizer and consequently the fertilizer use efficiency. Most of nitrogen was derived from the applied nitrogen fertilizer with maximum accumulation in tuber rather than shoots or roots of both potato varieties. Gradual increase of tuber starch with increasing salinity levels was noticed with addition of 2.6 kg/m2 of organic matter. In general, Spunta variety showed some superiority in tuber starch over those of Nicola variety tuber

  11. Warming and Nitrogen Addition Alter Photosynthetic Pigments, Sugars and Nutrients in a Temperate Meadow Ecosystem

    Science.gov (United States)

    Zhang, Tao; Yang, Shaobo; Guo, Rui; Guo, Jixun

    2016-01-01

    Global warming and nitrogen (N) deposition have an important influence on terrestrial ecosystems; however, the influence of warming and N deposition on plant photosynthetic products and nutrient cycling in plants is not well understood. We examined the effects of 3 years of warming and N addition on the plant photosynthetic products, foliar chemistry and stoichiometric ratios of two dominant species, i.e., Leymus chinensis and Phragmites communis, in a temperate meadow in northeastern China. Warming significantly increased the chlorophyll content and soluble sugars in L. chinensis but had no impact on the carotenoid and fructose contents. N addition caused a significant increase in the carotenoid and fructose contents. Warming and N addition had little impact on the photosynthetic products of P. communis. Warming caused significant decreases in the N and phosphorus (P) concentrations and significantly increased the carbon (C):P and N:P ratios of L. chinensis, but not the C concentration or the C:N ratio. N addition significantly increased the N concentration, C:P and N:P ratios, but significantly reduced the C:N ratio of L. chinensis. Warming significantly increased P. communis C and P concentrations, and the C:N and C:P ratios, whereas N addition increased the C, N and P concentrations but had no impact on the stoichiometric variables. This study suggests that both warming and N addition have direct impacts on plant photosynthates and elemental stoichiometry, which may play a vital role in plant-mediated biogeochemical cycling in temperate meadow ecosystems. PMID:27171176

  12. Growth and Yield of Chili Pepper as Affected by Weed Based Organic Compost and Nitrogen Fertilizer

    Directory of Open Access Journals (Sweden)

    Nanik Setyowati

    2014-01-01

    Full Text Available Fertility improvement of Ultisol is inevitable to increase growth and yield of chili pepper since the nutrient availability and organic matter of this soil is relatively low. Application of organic fertilizer will enhance microorganism activity in soil, thereafter will improve the availability of nutrients as well as other chemical, physical, biological properties of the soil. Most of manure releases nutrient quite slowly; therefore, addition of nitrogen to soil is expected to speed up the availability of nutrient to plant. Weed based organic fertilizers from Wedelia (Wedelia trilobata and Siam weed (Chromolaena odorata biomass have potential to substitute inorganic fertilizer. The objective of the experiment was to compare the effects of weed based organic compost and dry leaves compost with or without addition of nitrogen fertilizer on growth and yield of chili pepper. The experiment was carried out using Completely Randomized Design (CRD with treatments of 200 kg urea ha-1; Wedelia compost (WDC 20 ton ha-1; WDC 15, 10, and 5 ton ha-1 with addition of 200 kg urea ha-1 respectively; Siam weed compost (SWC 20 ton ha-1, SWC 15, 10, and 5 ton ha-1 with addition of  200 kg urea ha-1 respectively; and dry leaves compost (DLC 20 ton ha-1, DLC 15, 10, and 5 ton ha-1 with addition of 200 kg urea ha-1 respectively. The result revealed that composts with or without addition of nitrogen fertilizer had similar responses on the growth of chili pepper. Wedelia and Siam weeds compost at 20 ton ha-1 tended to give better yield of chili pepper as compared to application of urea alone. This result indicated that weed based organic fertilizers could substitute nitrogen fertilizer.

  13. Soil Organic Matter Responses to Chronic Nitrogen Additions in a Temperate Forest (Invited)

    Science.gov (United States)

    Frey, S. D.; Nadelhoffer, K.; Bowden, R.; Brzostek, E. R.; Caldwell, B. A.; Crow, S. E.; Finzi, A. C.; Goodale, C. L.; Grandy, S.; Lajtha, K.; Ollinger, S. V.; Plante, A. F.

    2010-12-01

    The Chronic Nitrogen Addition Experiment at Harvard Forest in central Massacusetts, USA was established in 1988 to investigate the effects of increasing anthropogenic atmospheric N deposition on forests in the eastern United States. Located in an old red pine plantation and a mixed hardwood forest, the treated plots have received 50 and 150 kg N/ha/yr, as ammonium sulfate, in six equal monthly applications during the growing season each year since the start of the experiment. Additionally, the control and low N treatments were given a single pulse label of 15N-nitrate or 15N-ammonium in 1991 and 1992. Regular measurements have been made over the past 20 years to assess woody biomass production and mortality, foliar chemistry, litter fall, and soil N dynamics. Less frequent measurements of soil C pools, soil respiration, fine root dynamics, and microbial biomass and community structure have been made. For the 20th anniversary, an intensive sampling campaign was carried out in fall 2008 with a focus on evaluating how the long-term N additions have impacted ecosystem C storage and N dynamics. Our primary objective was to assess the amount of C and N stored in wood, foliage, litter, roots, and soil (to a depth of ~50 cm). We also wanted to examine the fate of N by comparing patterns of 15N recovery to those observed previously. An additional objective was to further examine how chronic N additions impact microbial biomass, activity and community structure. Results indicate that chronic N additions over the past 20 years have increased forest floor mass and soil organic matter across the soil profile; decreased microbial biomass, especially the fungal component; and altered microbial community composition (i.e., significantly lower fungal:bacterial biomass ratios in the N amended plots). N15 tracer recoveries in soils and forest floors were much higher than in tree biomass, ranging from 49 to 101% of additions across forest types and N addition rates. Stoichiometric

  14. Influence of Nitrogen Containing Wastes Addition on Natural Aerobic Composting of Rice Straw

    Directory of Open Access Journals (Sweden)

    Thaniya Kaosol

    2012-01-01

    Full Text Available Problem statement: Rice straw is an agricultural residue. Typically, the rice straw can be burn in the rice field after the harvesting process. The burning can cause air pollution. Another alternative rice straw management method is animal feed. The amount of rice straw is enormus in Thailand. Another sustainable way to manage rice straw is required. Rice straw is used as main waste to compost with nitrogen containing wastes such as golden apple snail, cattle dung and urea in natural aerobic composting reactors. The golden apple snail is a pesticide and cattle dung is an animal waste. Both materials are all waste of low values. The main purpose of this study was to determine the influence of nitrogen containing wastes addition to rice straw on the performance of natural aerobic composting process in terms of the following parameters: pH, temperature, organic matter, C/N ratio, electrical conductivity and GI. The impact of this study is to reuse agriculture residue by composting. Approach: The experiments was consisted of three reactors. The reactor 1 contains the rice straws and golden apple snails while the reactor 2 contains the rice straws, golden apple snails and urea. The reactor 3 contains the rice straws, cattle dung and urea. The experiments were carried out in designed natural aerobic reactors (60 L under controlled laboratory conditions over 60 days. The analysis was done every 5 days however the temperature was measured daily. Results: The experimental results showed that the initial C/N ratio was 30.7, 30.3 and 31.8 in the reactor 1, 2 and 3, respectively. After the 60-day period, the final C/N ratio was reduced to 17.9, 16.9 and 18.4 in the reactor 1, 2 and 3, respectively. The main nutrients (N: P: K from all reactors achieved the standard level for Thai compost standard. The rice straw as agricultural residue was suitable for co-composting with golden apple snails and cattle dung as the nitrogen containing wastes. Conclusion: The

  15. Reassessing carbon sequestration in the North China Plain via addition of nitrogen.

    Science.gov (United States)

    Dong, Wenxu; Duan, Yongmei; Wang, Yuying; Hu, Chunsheng

    2016-09-01

    Soil inorganic carbon (SIC) exerts a strong influence on the carbon (C) sequestered in response to nitrogen (N) additions in arid and semi-arid ecosystems, but limited information is available on in situ SIC storage and dissolution at the field level. This study determined the soil organic/inorganic carbon storage in the soil profile at 0-100cm depths and the concentration of dissolved inorganic carbon (DIC) in soil leachate in 4N application treatments (0, 200, 400, and 600kgNha(-1)yr(-)(1)) for 15years in the North China Plain. The objectives were to evaluate the effect of nitrogen fertilizer on total amount of carbon sequestration and the uptake of atmospheric CO2 in an agricultural system. Results showed that after 15years of N fertilizer application the SOC contents at depths of 0-100cm significantly increased, whereas the SIC contents significantly decreased at depths of 0-60cm. However, the actual measured loss of carbonate was far higher than the theoretical maximum values of dissolution via protons from nitrification. Furthermore, the amount of HCO3(-) and the HCO3(-)/(Ca(2+)+Mg(2+)) ratio in soil leachate were higher in the N application treatments than no fertilizer input (CK) for the 0-80cm depth. The result suggested that the dissolution of carbonate was mainly enhanced by soil carbonic acid, a process which can absorb soil or atmosphere CO2 and less influenced by protons through the nitrification which would release CO2. To accurately evaluate soil C sequestration under N input scenarios in semi-arid regions, future studies should include both changes in SIC storage as well as the fractions of dissolution with different sources of acids in soil profiles. PMID:27135576

  16. Biological soil crusts emit large amounts of NO and HONO affecting the nitrogen cycle in drylands

    Science.gov (United States)

    Tamm, Alexandra; Wu, Dianming; Ruckteschler, Nina; Rodríguez-Caballero, Emilio; Steinkamp, Jörg; Meusel, Hannah; Elbert, Wolfgang; Behrendt, Thomas; Sörgel, Matthias; Cheng, Yafang; Crutzen, Paul J.; Su, Hang; Pöschl, Ulrich; Weber, Bettina

    2016-04-01

    Dryland systems currently cover ˜40% of the world's land surface and are still expanding as a consequence of human impact and global change. In contrast to that, information on their role in global biochemical processes is limited, probably induced by the presumption that their sparse vegetation cover plays a negligible role in global balances. However, spaces between the sparse shrubs are not bare, but soils are mostly covered by biological soil crusts (biocrusts). These biocrust communities belong to the oldest life forms, resulting from an assembly between soil particles and cyanobacteria, lichens, bryophytes, and algae plus heterotrophic organisms in varying proportions. Depending on the dominating organism group, cyanobacteria-, lichen-, and bryophyte-dominated biocrusts are distinguished. Besides their ability to restrict soil erosion they fix atmospheric carbon and nitrogen, and by doing this they serve as a nutrient source in strongly depleted dryland ecosystems. In this study we show that a fraction of the nitrogen fixed by biocrusts is metabolized and subsequently returned to the atmosphere in the form of nitric oxide (NO) and nitrous acid (HONO). These gases affect the radical formation and oxidizing capacity within the troposphere, thus being of particular interest to atmospheric chemistry. Laboratory measurements using dynamic chamber systems showed that dark cyanobacteria-dominated crusts emitted the largest amounts of NO and HONO, being ˜20 times higher than trace gas fluxes of nearby bare soil. We showed that these nitrogen emissions have a biogenic origin, as emissions of formerly strongly emitting samples almost completely ceased after sterilization. By combining laboratory, field, and satellite measurement data we made a best estimate of global annual emissions amounting to ˜1.1 Tg of NO-N and ˜0.6 Tg of HONO-N from biocrusts. This sum of 1.7 Tg of reactive nitrogen emissions equals ˜20% of the soil release under natural vegetation according

  17. Growth and Yield of Chili Pepper as Affected by Weed Based Organic Compost and Nitrogen Fertilizer

    OpenAIRE

    Nanik Setyowati; Zainal Muktamar; Bani Suriyanti; Marulak Simarmata

    2014-01-01

    Fertility improvement of Ultisol is inevitable to increase growth and yield of chili pepper since the nutrient availability and organic matter of this soil is relatively low. Application of organic fertilizer will enhance microorganism activity in soil, thereafter will improve the availability of nutrients as well as other chemical, physical, biological properties of the soil. Most of manure releases nutrient quite slowly; therefore, addition of nitrogen to soil is expected to speed up the av...

  18. Transcriptomic response of the red tide dinoflagellate, Karenia brevis, to nitrogen and phosphorus depletion and addition

    Directory of Open Access Journals (Sweden)

    Johnson Jillian G

    2011-07-01

    Full Text Available Abstract Background The role of coastal nutrient sources in the persistence of Karenia brevis red tides in coastal waters of Florida is a contentious issue that warrants investigation into the regulation of nutrient responses in this dinoflagellate. In other phytoplankton studied, nutrient status is reflected by the expression levels of N- and P-responsive gene transcripts. In dinoflagellates, however, many processes are regulated post-transcriptionally. All nuclear encoded gene transcripts studied to date possess a 5' trans-spliced leader (SL sequence suggestive, based on the trypanosome model, of post-transcriptional regulation. The current study therefore sought to determine if the transcriptome of K. brevis is responsive to nitrogen and phosphorus and is informative of nutrient status. Results Microarray analysis of N-depleted K. brevis cultures revealed an increase in the expression of transcripts involved in N-assimilation (nitrate and ammonium transporters, glutamine synthetases relative to nutrient replete cells. In contrast, a transcriptional signal of P-starvation was not apparent despite evidence of P-starvation based on their rapid growth response to P-addition. To study transcriptome responses to nutrient addition, the limiting nutrient was added to depleted cells and changes in global gene expression were assessed over the first 48 hours following nutrient addition. Both N- and P-addition resulted in significant changes in approximately 4% of genes on the microarray, using a significance cutoff of 1.7-fold and p ≤ 10-4. By far, the earliest responding genes were dominated in both nutrient treatments by pentatricopeptide repeat (PPR proteins, which increased in expression up to 3-fold by 1 h following nutrient addition. PPR proteins are nuclear encoded proteins involved in chloroplast and mitochondria RNA processing. Correspondingly, other functions enriched in response to both nutrients were photosystem and ribosomal genes

  19. Familial Vulnerability to ADHD Affects Activity in the Cerebellum in Addition to the Prefrontal Systems

    Science.gov (United States)

    Mulder, Martijn J.; Baeyens, Dieter; Davidson, Matthew C.; Casey, B. J.; Van Den Ban, Els; Van Engeland, Herman; Durston, Sarah

    2008-01-01

    The study examines whether cerebellar systems are sensitive to familial risk for ADHD in addition to frontostriatal circuitry. The results conclude that familial vulnerability to ADHD affects activity in both the prefrontal cortex and cerebellum.

  20. Effects of nitrogen additions on above- and belowground carbon dynamics in two tropical forests

    Energy Technology Data Exchange (ETDEWEB)

    Cusack, D.; Silver, W.L.; Torn, M.S.; McDowell, W.H.

    2011-04-15

    Anthropogenic nitrogen (N) deposition is increasing rapidly in tropical regions, adding N to ecosystems that often have high background N availability. Tropical forests play an important role in the global carbon (C) cycle, yet the effects of N deposition on C cycling in these ecosystems are poorly understood. We used a field N-fertilization experiment in lower and upper elevation tropical rain forests in Puerto Rico to explore the responses of above- and belowground C pools to N addition. As expected, tree stem growth and litterfall productivity did not respond to N fertilization in either of these Nrich forests, indicating a lack of N limitation to net primary productivity (NPP). In contrast, soil C concentrations increased significantly with N fertilization in both forests, leading to larger C stocks in fertilized plots. However, different soil C pools responded to N fertilization differently. Labile (low density) soil C fractions and live fine roots declined with fertilization, while mineral-associated soil C increased in both forests. Decreased soil CO2 fluxes in fertilized plots were correlated with smaller labile soil C pools in the lower elevation forest (R2 = 0.65, p\\0.05), and with lower live fine root biomass in the upper elevation forest (R2 = 0.90, p\\0.05). Our results indicate that soil C storage is sensitive to N deposition in tropical forests, even where plant productivity is not N-limited. The mineral-associated soil C pool has the potential to respond relatively quickly to N additions, and can drive increases in bulk soil C stocks in tropical forests.

  1. Methane flux in non-wetland soils in response to nitrogen addition: a meta-analysis.

    Science.gov (United States)

    Aronson, E L; Helliker, B R

    2010-11-01

    The controls on methane (CH4) flux into and out of soils are not well understood. Environmental variables including temperature, precipitation, and nitrogen (N) status can have strong effects on the magnitude and direction (e.g., uptake vs. release) of CH4 flux. To better understand the interactions between CH4-cycling microorganisms and N in the non-wetland soil system, a meta-analysis was performed on published literature comparing CH4 flux in N amended and matched control plots. An appropriate study index was developed for this purpose. It was found that smaller amounts of N tended to stimulate CH4 uptake while larger amounts tended to inhibit uptake by the soil. When all other variables were accounted for, the switch occurred at 100 kg N x ha(-1) x yr(-1). Managed land and land with a longer duration of fertilization showed greater inhibition of CH4 uptake with added N. These results support the hypotheses that large amounts of available N can inhibit methanotrophy, but also that methanotrophs in upland soils can be N limited in their consumption of CH4 from the atmosphere. There were interactions between other variables and N addition on the CH4 flux response: lower temperature and, to a lesser extent, higher precipitation magnified the inhibition of CH4 uptake due to N addition. Several mechanisms that may cause these trends are discussed, but none could be conclusively supported with this approach. Further controlled and in situ study should be undertaken to isolate the correct mechanism(s) responsible and to model upland CH4 flux. PMID:21141185

  2. Effect of nitrogen on structure and mechanical properties of ductile iron with small additions vanadium and niobium

    Directory of Open Access Journals (Sweden)

    Fraś E.

    2007-01-01

    Full Text Available Results of investigations of influence of small additions of vanadium (about 0,08 and 0,12 % V and niobium (about 0,05 and 0,16% Nb as well as nitrogen (32 - 58 ppm. on mechanical properties and structure of ductile iron is presented. Effect of these additions on graphite diameter distribution, nodule count, and ferrite fraction is determined. It has been also shown that vanadium and niobium lead to formation of their complex carbides, while nitrogen – complex carbide-nitrides containing magnesium and silicon.

  3. Effect of nitrogen on structure and mechanical properties of ductile iron with small additions vanadium and niobium

    OpenAIRE

    Fraś E.; Górny M.; Kawalec M.

    2007-01-01

    Results of investigations of influence of small additions of vanadium (about 0,08 and 0,12 % V) and niobium (about 0,05 and 0,16% Nb) as well as nitrogen (32 - 58 ppm.) on mechanical properties and structure of ductile iron is presented. Effect of these additions on graphite diameter distribution, nodule count, and ferrite fraction is determined. It has been also shown that vanadium and niobium lead to formation of their complex carbides, while nitrogen – complex carbide-nitrides containing m...

  4. Nitrogen and phosphorus addition impact soil N2O emission in a secondary tropical forest of South China

    OpenAIRE

    Faming Wang; Jian Li; Xiaoli Wang; Wei Zhang; Bi Zou; Deborah A Neher; Zhian Li

    2014-01-01

    Nutrient availability greatly regulates ecosystem processes and functions of tropical forests. However, few studies have explored impacts of N addition (aN), P addition (aP) and N×P interaction on tropical forests N2O fluxes. We established an N and P addition experiment in a tropical forest to test whether: (1) N addition would increase N2O emission and nitrification, and (2) P addition would increase N2O emission and N transformations. Nitrogen and P addition had no effect on N mineralizati...

  5. Kinetics of addition of nitrogen-15 labelled nitrates to organic matter in a calcareous soil

    International Nuclear Information System (INIS)

    In a calcareous soil the transformation of added nitrates with or without wheat straw was studied. By using 15N it was possible to compare the net and real nitrification of the organic soil nitrogen, the mineral nitrogen organization and the denitrification losses. The observed priming effect was interpreted as a result of some modifications of nitrification-organization kinetics due to the high nitrate fertilization. The net nitrification is about three times less than the primary nitrification which is likely to be found even in a period of high organization. Finally the losses by denitrification appear even with a straw which immobilizes the nitrate nitrogen

  6. Influence of additional alloying with nitrogen on structure and properties of high chromium steel Kh17 after hot rolling

    International Nuclear Information System (INIS)

    A study was made into the structure and mechanical properties of steel Kh17 with 0.16% N after hot rolling under various conditions. It is shown that nitrogen alloying promotes steel transition into a two-phase state (α+γ) in heating above 850 deg C and affects mechanical properties of the steel in a hot rolled state. Impact strength is at its maximum in nitrogen containing steel kh17 if the rolling is in the temperature range of α-phase solid solution. Depending on the temperatures of hot rolling beginning and completion the distinctions in steel microstructure are investigated

  7. Improved RDX detoxification with starch addition using a novel nitrogen-fixing aerobic microbial consortium from soil contaminated with explosives.

    Science.gov (United States)

    Khan, Muhammad Imran; Yang, Jihoon; Yoo, Byungun; Park, Joonhong

    2015-04-28

    In this work, we developed and characterized a novel nitrogen-fixing aerobic microbial consortium for the complete detoxification of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Aerobic RDX biodegradation coupled with microbial growth and nitrogen fixation activity were effectively stimulated by the co-addition of starch and RDX under nitrogen limiting conditions. In the starch-stimulated nitrogen-fixing RDX degradative consortium, the RDX degradation activity was correlated with the xplA and nifH gene copy numbers, suggesting the involvement of nitrogen fixing populations in RDX biodegradation. Formate, nitrite, nitrate, and ammonia were detected as aerobic RDX degradation intermediates without the accumulation of any nitroso-derivatives or NDAB (4-nitro-2,4-diazabutanal), indicating nearly complete mineralization. Pyrosequencing targeting the bacterial 16S rRNA genes revealed that the Rhizobium, Rhizobacter and Terrimonas population increased as the RDX degradation activity increased, suggesting their involvement in the degradation process. These findings imply that the nitrogen-fixing aerobic RDX degrading consortium is a valuable microbial resource for improving the detoxification of RDX-contaminated soil or groundwater, especially when combined with rhizoremediation. PMID:25661171

  8. Influence of microelement addition on the pitting corrosion resistance of nitrogen-containing stainless steel

    International Nuclear Information System (INIS)

    To improve the performance of stainless steel, we subjected solid-state steel to a nitrogen absorption treatment. In the fabrication process, a commercially available high-chromium ferritic stainless steel (Fe-22Cr-1Mo) was heat-treated at 1423 K in a nitrogen atmosphere. The heat-treatment transformed the ferric phase into the austenite phase. This process loaded over 1 mass% of nitrogen into the steel material. Most of the added nitrogen formed a solid solution in the matrix, but a minor portion formed nitrides with the very small quantities of elements such as titanium and aluminum that pre-existed in the steel. The nitrogen-containing steels were then analyzed by pitting potential measurements and ferric chloride corrosion examination. The pitting corrosion resistance of Fe-22Cr-1Mo-1N exceeded that of conventional materials such as Fe-18Cr-12Ni and Fe-22Cr-1Mo. However in the ferric chloride corrosion tests, pits developed in Fe-22Cr-1Mo-1N at temperatures above 323 K. These pits were possibly initiated at the sites of minute nitride resulting from the nitrogen absorption process. (author)

  9. Water- and Plant-Mediated Responses of Ecosystem Carbon Fluxes to Warming and Nitrogen Addition on the Songnen Grassland in Northeast China

    Science.gov (United States)

    Jiang, Li; Guo, Rui; Zhu, Tingcheng; Niu, Xuedun; Guo, Jixun; Sun, Wei

    2012-01-01

    Background Understanding how grasslands are affected by a long-term increase in temperature is crucial to predict the future impact of global climate change on terrestrial ecosystems. Additionally, it is not clear how the effects of global warming on grassland productivity are going to be altered by increased N deposition and N addition. Methodology/Principal Findings In-situ canopy CO2 exchange rates were measured in a meadow steppe subjected to 4-year warming and nitrogen addition treatments. Warming treatment reduced net ecosystem CO2 exchange (NEE) and increased ecosystem respiration (ER); but had no significant impacts on gross ecosystem productivity (GEP). N addition increased NEE, ER and GEP. However, there were no significant interactions between N addition and warming. The variation of NEE during the four experimental years was correlated with soil water content, particularly during early spring, suggesting that water availability is a primary driver of carbon fluxes in the studied semi-arid grassland. Conclusion/Significance Ecosystem carbon fluxes in grassland ecosystems are sensitive to warming and N addition. In the studied water-limited grassland, both warming and N addition influence ecosystem carbon fluxes by affecting water availability, which is the primary driver in many arid and semiarid ecosystems. It remains unknown to what extent the long-term N addition would affect the turn-over of soil organic matter and the C sink size of this grassland. PMID:23028848

  10. Effect of nitrogen fertilizer rats combined with organic additives on sorghum growth using 15N isotope technique

    International Nuclear Information System (INIS)

    A pot experiment was conducted under green house conditions to evaluate the benefits from N fertilizer and organic manure to sorghum plants grown in calcareous soil. Labelled ammonium sulphate with 1% 15N atom excess was applied at rates of 0, 100 and 150 kg fed-1. Organic compost was applied at rates of 0, 50 and 100 g pot-1 on basis of its nitrogen content. Zinc, as zinc sulphate, was added at rates of 0, 5 and 10 mg kg-1 soil. The obtained data indicated that the dry matter yield of both shoot and roots of sorghum was positively affected by addition of N fertilizer, organic compost and Zn levels. Similarly, the N uptake was enhanced by application of 150 kg N fed-1, 100 g pot-1 of compost and 5 mg Zn kg-1 soil. 15N data revealed that the portion of N derived from fertilizer (Ndff) by shoots and roots was remarkable and followed the same trend of N uptake. Ndff utilized by shoots was higher than those uptakes by roots

  11. NITROGEN DEPOSITION AND ORGANIC MATTER MANIPULATIONS AFFECT GROSS AND NET NITROGEN TRANSFORMATIONS IN TWO TEMPERATE FORESTS SOILS

    Science.gov (United States)

    Soil nitrogen transformations are intricately linked to carbon transformations. We utilized two existing organic matter manipulation sites in western Oregon, USA and Hungary to investigate these linkages. Our questions were: 1) Does the quantity and quality of organic matter af...

  12. The Impact of Long-Term Nitrogen Addition on Microbial Community Composition in Three Hawaiian Forest Soils

    OpenAIRE

    Teri C. Balser

    2001-01-01

    We evaluated the microbial communities in three Hawaiian forest soils along a natural fertility gradient and compared their distinct responses to long-term nitrogen (N) additions. The sites studied have the same elevation, climate, and dominant vegetation, but vary in age of development, and thus in soil nutrient availability and nutrient limitation to plant growth. Fertilized plots at each site have received 100 kg ha year-1 N addition for at least 8 years. Soil parameters, water content, pH...

  13. Nitrogen

    Science.gov (United States)

    Kramer, D.A.

    2006-01-01

    In 2005, ammonia was produced by 15 companies at 26 plants in 16 states in the United States. Of the total ammonia production capacity, 55% was centered in Louisiana, Oklahoma and Texas because of their large reserves of natural gas. US producers operated at 66% of their rated capacity. In descending order, Koch Nitrogen, Terra Industries, CF Industries, Agrium and PCS Nitrogen accounted for 81% of the US ammonia production capacity.

  14. Dynamics of soil inorganic nitrogen and their responses to nitrogen additions in three subtropical forests, south China

    DEFF Research Database (Denmark)

    Fang, Yun-ting; Zhu, Wei-xing; Mo, Jiang-ming;

    2006-01-01

    Three forests with different historical land-use, forest age, and species assemblages in subtropical China were selected to evaluate current soil N status and investigate the responses of soil inorganic N dynamics to monthly ammonium nitrate additions. Results showed that the mature monsoon...

  15. Dynamics of soil inorganic nitrogen and their responses to nitrogen additions in three subtropical forests, south China

    Institute of Scientific and Technical Information of China (English)

    FANG Yun-ting; ZHU Wei-xing; MO Jiang-ming; ZHOU Guo-yi; GUNDERSEN Per

    2006-01-01

    Three forests with different historical land-use, forest age, and species assemblages in subtropical China were selected to evaluate current soil N status and investigate the responses of soil inorganic N dynamics to monthly ammonium nitrate additions.Results showed that the mature monsoon evergreen broadleaved forest that has been protected for more than 400 years exhibited an advanced soil N status than the pine (Pinus massoniana) and pine-broadleaf mixed forests, both originated from the 1930's clear-cut and pine plantation. Mature forests had greater extractable inorganic N pool, lower N retention capacity, higher inorganic N leaching,and higher soil C/N ratios. Mineral soil extractable NH4+-N and NO3--N concentrations were significantly increased by experimental N additions on several sampling dates, but repeated ANOVA showed that the effect was not significant over the whole year except NH4+-N in the mature forest. In contrast, inorganic N (both NH4+-N and NO3--N) in soil 20-cm below the surface was significantly elevated by the N additions. From 42% to 74% of N added was retained by the upper 20 cm soils in the pine and mixed forests, while 0%-70% was retained in the mature forest. Our results suggest that land-use history, forest age and species composition were likely to be some of the important factors that determine differing forest N retention responses to elevated N deposition in the study region.

  16. Dissolved organic carbon and nitrogen mineralization strongly affect co2 emissions following lime application to acidic soil

    International Nuclear Information System (INIS)

    Emission of greenhouse gases from agricultural soils has main contribution to the climatic change and global warming. Dynamics of dissolved organic carbon (DOC) and nitrogen mineralization can affect CO/sub 2/ emission from soils. Influence of DOC and nitrogen mineralization on CO/sub 2/ emissions following lime application to acidic soil was investigated in current study. Laboratory experiment was conducted under aerobic conditions with 25% moisture contents (66% water-filled pore space) at 25 degree C in the dark conditions. Different treatments of lime were applied to acidic soil as follows: CK (control), L (low rate of lime: 0.2g lime / 100 g soil) and H (high rate of lime: 0.5g lime /100g soil). CO/sub 2/ emissions were measured by gas chromatography and dissolved organic carbon, NH4 +-N, NO/sub 3/ --N and soil pH were measured during incubation study. Addition of lime to acidic soil significantly increased the concentration of DOC and N mineralization rate. Higher concentrations of DOC and N mineralization, consequently, increased the CO/sub 2/ emissions from lime treated soils. Cumulative CO/sub 2/ emission was 75% and 71% higher from L and H treatments as compared to CK. The results of current study suggest that DOC and N mineralization are critical in controlling gaseous emissions of CO/sub 2/ from acidic soils following lime application. (author)

  17. Nitrogen Addition and Warming Independently Influence the Belowground Micro-Food Web in a Temperate Steppe

    NARCIS (Netherlands)

    Li, Q.; Bai, H.; Liang, W.; Xia, J.; Wan, S.; Putten, van der W.H.

    2013-01-01

    Climate warming and atmospheric nitrogen (N) deposition are known to influence ecosystem structure and functioning. However, our understanding of the interactive effect of these global changes on ecosystem functioning is relatively limited, especially when it concerns the responses of soils and soil

  18. Study on Tribological Behaviors of Boron-Nitrogen Modified Fatty Acid as Water-Based Lube Additives

    Institute of Scientific and Technical Information of China (English)

    FANG Jian-hua; CHEN Bo-shui; DONG Ling; WANG Jiu

    2008-01-01

    A new type of boron-nitrogen modified fatty acid as water base lube additive was prepared and the chemical structure characterized by infrared spectrum. The tribological properties of the additive in water were evaluated by friction testers. The morphographies and tribochemical species of the worn surfaces were analyzed by means of X-ray Photoelectron Spectroscope (XPS). The results showed that the additive is excellent in increasing loadcarrying capacity, anti-wear and friction-reducing abilities of water. The lubrication mechanism is inferred that a high strength adsorption film and a tribochemical reaction film are formed on the rubbing surfaces due to the carrier effect of the long chain fatty acid molecules, high reaction activities of nitrogen, electron-deficient orbit of boron and their synergisms.

  19. Improved TNT detoxification by starch addition in a nitrogen-fixing Methylophilus-dominant aerobic microbial consortium.

    Science.gov (United States)

    Khan, Muhammad Imran; Lee, Jaejin; Yoo, Keunje; Kim, Seonghoon; Park, Joonhong

    2015-12-30

    In this study, a novel aerobic microbial consortium for the complete detoxification of 2,4,6-trinitrotoluene (TNT) was developed using starch as a slow-releasing carbon source under nitrogen-fixing conditions. Aerobic TNT biodegradation coupled with microbial growth was effectively stimulated by the co-addition of starch and TNT under nitrogen-fixing conditions. The addition of starch with TNT led to TNT mineralization via ring cleavage without accumulation of any toxic by-products, indicating improved TNT detoxification by the co-addition of starch and TNT. Pyrosequencing targeting the bacterial 16S rRNA gene suggested that Methylophilus and Pseudoxanthomonas population were significantly stimulated by the co-addition of starch and TNT and that the Methylophilus population became predominant in the consortium. Together with our previous study regarding starch-stimulated RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) degradation (Khan et al., J. Hazard. Mater. 287 (2015) 243-251), this work suggests that the co-addition of starch with a target explosive is an effective way to stimulate aerobic explosive degradation under nitrogen-fixing conditions for enhancing explosive detoxification. PMID:26342802

  20. Sonoran Desert winter annuals affected by density of red brome and soil nitrogen

    Science.gov (United States)

    Salo, L.F.; McPherson, G.R.; Williams, D.G.

    2005-01-01

    Red brome [Bromus madritensis subsp. rubens (L.) Husn.] is a Mediterranean winter annual grass that has invaded Southwestern USA deserts. This study evaluated interactions among 13 Sonoran Desert annual species at four densities of red brome from 0 to the equivalent of 1200 plants ma??2. We examined these interactions at low (3 I?g) and high (537 I?g NO3a?? g soila??1) nitrogen (N) to evaluate the relative effects of soil N level on survival and growth of native annuals and red brome. Red brome did not affect emergence or survival of native annuals, but significantly reduced growth of natives, raising concerns about effects of this exotic grass on the fecundity of these species. Differences in growth of red brome and of the three dominant non nitrogen-fixing native annuals at the two levels of soil N were similar. Total species biomass of red brome was reduced by 83% at low, compared to high, N levels, whereas that of the three native species was reduced by from 42 to 95%. Mean individual biomass of red brome was reduced by 87% at low, compared to high, N levels, whereas that of the three native species was reduced by from 72 to 89%.

  1. Use of Nitrogen-15 Isotope Method in Soils and Ground Water to Determine Potential Nitrogen Sources Affecting a Municipal Water Supply in Kansas, USA

    Science.gov (United States)

    Townsend, M. A.; Macko, S. A.

    2004-12-01

    Nitrate-N concentrations have increased to greater than 10 mg/L in a municipal water supply in western Kansas from 1995 to 2002. A study was done by the Kansas Geological Survey using the nitrogen-15 natural abundance isotope method to determine potential sources for the increasing nitrate concentrations. Preliminary results of the isotope analyses on water samples suggest that animal waste and/or denitrification enrichment has affected the water supply. Soil samples from areas near the wells that were not treated with manure show a general increase of nitrogen-15 signature (+9 to +15 \\permil) to a depth of 5 m. Soils are silt loams with measurable carbonate (0.8 to 2 % by weight) in the profile, which may permit volatilization enrichment to occur in the soil profile. Wells in the area range from 11 to 20 m in alluvial deposits with depth to water at approximately 9 m). Nitrate-N values range from 8 to 26 mg/L. Nitrogen-15 values range from (+17 to +28 \\permil) with no obvious source of animal waste near the well sites. There are potential nearby long-term sources of animal waste - an abandoned sewage treatment plant and an agricultural testing farm. One well has a reducing chemistry with a nitrate value of 0.9 mg/L and a nitrogen-15 value of +17 \\permil suggesting that alluvial sediment variation also has an impact on the water quality in the study area. The other wells show values of nitrate and nitrogen-15 that are much greater than the associated soils. The use of nitrogen-15 alone permited limited evaluation of sources of nitrate to ground water particularly in areas with carbonate in the soils. Use of oxygen-18 on nitrate will permit the delineation of the processes affecting the nitrogen in the soil profile and determination of the probable sources and the processes that have affected the nitrogen in the ground water. Final results of the nitrogen-15 and oxygen-18 analyses will be presented.

  2. Effects of nitrogen and phosphorus additions on soil microbial biomass and community structure in two reforested tropical forests

    OpenAIRE

    Lei Liu; Per Gundersen; , Wei Zhang; Tao Zhang; Hao Chen; Jiangming Mo

    2015-01-01

    Elevated nitrogen (N) deposition may aggravate phosphorus (P) deficiency in forests in the warm humid regions of China. To our knowledge, the interactive effects of long-term N deposition and P availability on soil microorganisms in tropical replanted forests remain unclear. We conducted an N and P manipulation experiment with four treatments: control, N addition (15 g N m−2·yr−1), P addition (15 g P m−2·yr−1), and N and P addition (15 + 15 g N and P m−2·yr−1, respectively) in disturbed (plan...

  3. The effect of nitrogen addition on biomass production and competition in three expansive tall grasses

    Czech Academy of Sciences Publication Activity Database

    Holub, Petr; Tůma, I.; Fiala, Karel

    2012-01-01

    Roč. 170, NOV 2012 (2012), s. 211-216. ISSN 0269-7491 R&D Projects: GA ČR(CZ) GA526/06/0556; GA MZe QJ1220007; GA MŠk(CZ) ED1.1.00/02.0073 Institutional support: RVO:67985939 ; RVO:67179843 Keywords : aboveground biomass * aggressivity * crowding coefficient * Nitrogen * tall grasses Subject RIV: EH - Ecology, Behaviour; EF - Botanics (BU-J) Impact factor: 3.730, year: 2012

  4. Influence of Nitrogen Containing Wastes Addition on Natural Aerobic Composting of Rice Straw

    OpenAIRE

    Thaniya Kaosol; Suchinun Kiepukdee; Prawit Towatana

    2012-01-01

    Problem statement: Rice straw is an agricultural residue. Typically, the rice straw can be burn in the rice field after the harvesting process. The burning can cause air pollution. Another alternative rice straw management method is animal feed. The amount of rice straw is enormus in Thailand. Another sustainable way to manage rice straw is required. Rice straw is used as main waste to compost with nitrogen containing wastes such as golden apple snail, cattle dung and urea in natural aerobic ...

  5. Diamond crystallization in a CO2-rich alkaline carbonate melt with a nitrogen additive

    Science.gov (United States)

    Khokhryakov, Alexander F.; Palyanov, Yuri N.; Kupriyanov, Igor N.; Nechaev, Denis V.

    2016-09-01

    Diamond crystallization was experimentally studied in a CO2-bearing alkaline carbonate melt with an increased content of nitrogen at pressure of 6.3 GPa and temperature of 1500 °C. The growth rate, morphology, internal structure of overgrown layers, and defect-impurity composition of newly formed diamond were investigated. The type of growth patterns on faces, internal structure, and nitrogen content were found to be controlled by both the crystallographic orientation of the growth surfaces and the structure of the original faces of diamond seed crystals. An overgrown layer has a uniform structure on the {100} plane faces of synthetic diamond and a fibrillar (fibrous) structure on the faceted surfaces of a natural diamond cube. The {111} faces have a polycentric vicinal relief with numerous twin intergrowths and micro twin lamellae. The stable form of diamond growth under experimental conditions is a curved-face hexoctahedron with small cube faces. The nitrogen impurity concentration in overgrown layers varies depending on the growth direction and surface type, from 100 to 1100 ppm.

  6. Effects of Nitrogen Addition on Leaf Decomposition of Single-Species and Litter Mixture in Pinus tabulaeformis Forests

    OpenAIRE

    Jinsong Wang; Wensheng Bu; Bo Zhao; Xiuhai Zhao; Chunyu Zhang; Juan Fan; Gadow, Klaus V.

    2015-01-01

    The litter decomposition process is closely correlated with nutrient cycling and the maintenance of soil fertility in the forest ecosystem. In particular, the intense environmental concern about atmospheric nitrogen (N) deposition requires a better understanding of its influence on the litter decomposition process. This study examines the responses of single-species litter and litter mixture decomposition processes to N addition in Chinese pine (Pinus tabulaeformis Carr.) ecosystems. Chinese ...

  7. Convergent Synthesis of Diverse Nitrogen Heterocycles via Rh(III)-Catalyzed C-H Conjugate Addition/Cyclization Reactions.

    Science.gov (United States)

    Weinstein, Adam B; Ellman, Jonathan A

    2016-07-01

    The development of Rh(III)-catalyzed C-H conjugate addition/cyclization reactions that provide access to synthetically useful fused bi- and tricyclic nitrogen heterocycles is reported. A broad scope of C-H functionalization substrates and electrophilic olefin coupling partners is effective, and depending on the nature of the directing group, cyclic imide, amide, or heteroaromatic products are obtained. An efficient synthesis of a pyrrolophenanthridine alkaloid natural product, oxoassoanine, highlights the utility of this method. PMID:27337641

  8. Climate change affects key nitrogen-fixing bacterial populations on coral reefs

    NARCIS (Netherlands)

    Santos, Henrique F.; Carmo, Flavia L.; Duarte, Gustavo; Dini-Andreote, Francisco; Castro, Clovis B.; Rosado, Alexandre S.; van Elsas, Jan Dirk; Peixoto, Raquel S.

    2014-01-01

    Coral reefs are at serious risk due to events associated with global climate change. Elevated ocean temperatures have unpredictable consequences for the ocean's biogeochemical cycles. The nitrogen cycle is driven by complex microbial transformations, including nitrogen fixation. This study investiga

  9. Zeolite Soil Application Method Affects Inorganic Nitrogen, Moisture, and Corn Growth

    Science.gov (United States)

    Adoption of new management techniques which improve soil water storage and soil nitrogen plant availability yet limit nitrogen leaching may help improve environmental quality. A benchtop study was conducted to determine the influence of a single urea fertilizer rate (224 kilograms of Nitrogen per ...

  10. Yield and Nicotine Content of Flue-Cured Tobacco as Affected by Soil Nitrogen Mineralization

    Institute of Scientific and Technical Information of China (English)

    JU Xiao-Tang; CHAO Feng-Chun; LI Chun-Jian; JIANG Rong-Feng; P.CHRISTIE; ZHANG Fu-Suo

    2008-01-01

    Nitrogen (N) supply is the most important factor affecting yield and quality of flue-cured tobacco (FCT).A field experiment and an in situ incubation method were used to study the effects of soil N mineralization in the later stages of growth on yield and nicotine content of FCT in Fenggang and Jiusha,Guizhou Province.The yield and market value of FCT at Fenggang were much lower than those at Jinsha.However,the nicotine content of middle and upper leaves was much higher at Fenggang than at Jiusha when the same rate of fertilizer N was applied,which might be due to a higher N supply capacity at the Fenggang site.At later stages of growth (7-16 weeks after transplanting),the soil net N mineralization at Fenggang (56 kg N ha-1) was almost double that at Jiusha (30 kg N ha-1).While soil NHa-N and NO3-N were almost exhausted by the plants or leached 5 weeks after transplanting,the N taken up at the later growth stages at Fenggang were mainly derived from soil N mineralization,which contributed to a high nicotine content in the upper leaves.The order of soil N contribution to N buildup in different leaves was:upper leaves > middle leaves > lower leaves.Thus,soil N mineralization at late growth stages was an important factor affecting N accumulation and therefore the nicotine content in the upper leaves.

  11. Volatilization of ammonia from manure as affected by manure additives, temperature and mixing.

    Science.gov (United States)

    Van der Stelt, B; Temminghoff, E J M; Van Vliet, P C J; Van Riemsdijk, W H

    2007-12-01

    Ammonia (NH(3)) volatilization decreases the N-nutrient value of livestock manure slurries and can lead to soil acidification and eutrophication problems. In this study the effect of three manure additives (Euro Mest-mix (Mx), Effective Micro-organisms (EM), and Agri-mest (Am)) on NH(3) volatilization at three temperatures (4, 20, and 35 degrees C) was investigated. The manufacturers claim that Mx contains absorbing clay minerals and that applying Am and EM to slurry will reduce nitrogen losses, most likely by enhancing the biodegradation of manure slurry. Furthermore, the effect of mixing slurry on NH(3) volatilization has been investigated. Ammonia volatilization increased with increasing temperature and mixing of the slurries. However, at 35 degrees C mixing of manure reduced NH(3) emissions compared to non-mixing, which is related to a reduced crust resistance to gaseous transport at higher temperatures for non-mixing. Moreover, mixing introduces oxygen into the anaerobic slurry environment which will slow down microbial activity. The use of additives did not change manure characteristics (pH, dry matter, N(total), N(mineral), C/N, and C/N(organic)) and did not result in a significant (p<0.05) decrease in NH(3) emissions, except that at 4 degrees C and no mixing a significant decrease of 34% in NH(3) volatilization was observed, when Am and EM together, were applied to slurry. PMID:17215124

  12. Carbon flux from plants to soil microbes is highly sensitive to nitrogen addition and biochar amendment

    Science.gov (United States)

    Kaiser, C.; Solaiman, Z. M.; Kilburn, M. R.; Clode, P. L.; Fuchslueger, L.; Koranda, M.; Murphy, D. V.

    2012-04-01

    The release of carbon through plant roots to the soil has been recognized as a governing factor for soil microbial community composition and decomposition processes, constituting an important control for ecosystem biogeochemical cycles. Moreover, there is increasing awareness that the flux of recently assimilated carbon from plants to the soil may regulate ecosystem response to environmental change, as the rate of the plant-soil carbon transfer will likely be affected by increased plant C assimilation caused by increasing atmospheric CO2 levels. What has received less attention so far is how sensitive the plant-soil C transfer would be to possible regulations coming from belowground, such as soil N addition or microbial community changes resulting from anthropogenic inputs such as biochar amendments. In this study we investigated the size, rate and sensitivity of the transfer of recently assimilated plant C through the root-soil-mycorrhiza-microbial continuum. Wheat plants associated with arbuscular mycorrhizal fungi were grown in split-boxes which were filled either with soil or a soil-biochar mixture. Each split-box consisted of two compartments separated by a membrane which was penetrable for mycorrhizal hyphae but not for roots. Wheat plants were only grown in one compartment while the other compartment served as an extended soil volume which was only accessible by mycorrhizal hyphae associated with the plant roots. After plants were grown for four weeks we used a double-labeling approach with 13C and 15N in order to investigate interactions between C and N flows in the plant-soil-microorganism system. Plants were subjected to an enriched 13CO2 atmosphere for 8 hours during which 15NH4 was added to a subset of split-boxes to either the root-containing or the root-free compartment. Both, 13C and 15N fluxes through the plant-soil continuum were monitored over 24 hours by stable isotope methods (13C phospho-lipid fatty acids by GC-IRMS, 15N/13C in bulk plant

  13. Influences of Nitrogen Addition and Annealing on the Microstructure and Corrosion Resistance of Fe-Cr-Mn-W Stainless Steels(I)

    International Nuclear Information System (INIS)

    Influences of Nitrogen addition and annealing heat treatment on the properties of Fe-Cr-Mn-W Stainless Steels for the low activation material of a fusion reactor component were studied. OM, TEM, VSM, and XRD analyses wee used to study the microstructural changes of the alloys. Mechanical properties were investigated by means of a tension test and a Vickers hardness test, and corrosion resistance was evaluated using an anodic polarization test, 6% FeCl3 immersion test, 65% boiling nitric acid immersion test, and hydrogen embrittlement test. Increasing nitrogen content in Fe-Cr-Mn-W alloys reduced ferrite content and improved partitioning coefficient of chromium between austenite and ferrite. The microstructures of the alloys observed by OM were in accordance with the thermodynamically calculated phase diagram, but ε martensite was formed by water quenching when the stable phase at annealing temperature was austenite. With increasing annealing temperature, corrosion resistance was improved, and anodic polarization resistance of high nitrogen bearing Alloy 6 was better than that of STS 304. The results of the corrosion tests showed that corrosion resistance of Fe-Cr-Mn-W alloys was affected by not only alloying elements but also the presence of the 2' nd phase

  14. Solvent extraction of nitrogen heterocyclic compounds contained in coal tar absorption oil fraction - Improvement of separation performance by addition of aluminum chloride to solvent

    Energy Technology Data Exchange (ETDEWEB)

    Egashira, R.; Salim, C. [Tokyo Institute of Technology, Tokyo (Japan). Dept. of International Development Engineering, Graduate School of Science and Engineering

    2001-05-01

    The liquid-liquid equilibrium properties between the coal tar absorption oil fraction feed and the solvent (aqueous solution of methanol and aluminum chloride) were experimentally measured for nitrogen heterocyclic compounds (2,3-benzopyridine (quinoline), 3,4-benzopyridine (isoquinoline), and 2,3-benzopyrrole (indole)), homocyclic compounds (aromatics), and oxygen heterocyclic compounds. Nitrogen compounds were, extracted preferentially to the other compounds, and no oxygen compound was detected in the extract under all conditions. The distribution ratios of nitrogen compounds and aromatics increased with a larger mass fraction of AlCl{sub 3} in the extract. This increase in the distribution ratio was especially large for quinoline and isoquinoline, and the maximum ratios of quinoline and isoquinoline were 26 and 85 times larger, respectively, than in the cases without AlCl{sub 3} in the solvent. The separation selectivities for quinoline and isoquinoline relative to aromatics increased considerably with the mass fraction of AlCl{sub 3} in the extract, and the maximum ratios were 5 and 17 times higher than in the cases without AlCl{sub 3}. The separation selectivity for indole was apparently not affected by the addition of AlCl{sub 3}.

  15. Effect of SF6 and NF3 additives on UV and IR lasing in nitrogen

    International Nuclear Information System (INIS)

    The lasing regimes of nitrogen laser on the C3Πu - B3Πg transition with a high-energy long laser pulse under pumping by a transverse discharge in N2 - SF6 (NF3) mixtures from generators with a semiconductor opening switch is studied. Laser pulses with two peaks and controlled delay between these peaks are obtained. It is shown that the time interval between the peaks may exceed 50 ns for N2 - NF3 mixtures. The conditions for obtaining effective UV lasing with a laser pulse width of more than 50 ns at the base level are determined. A possibility of depopulating the lower level of the C3Πu - B3Πg transition by induced transitions in the first positive B3Πg - A3Σu+ system is shown; this process makes it possible to expand the pulse to 100 ns at λ = 337.1 nm. The highest lasing energy and power in the IR and UV spectral ranges are obtained for nitrogen lasers with spark preionisation. (lasers)

  16. Effect of SF6 and NF3 additives on UV and IR lasing in nitrogen

    Science.gov (United States)

    Genin, D. E.; Panchenko, Aleksei N.; Tarasenko, Viktor F.; Tel'minov, A. E.

    2011-04-01

    The lasing regimes of nitrogen laser on the C3Πu — B3Πg transition with a high-energy long laser pulse under pumping by a transverse discharge in N2 — SF6 (NF3) mixtures from generators with a semiconductor opening switch is studied. Laser pulses with two peaks and controlled delay between these peaks are obtained. It is shown that the time interval between the peaks may exceed 50 ns for N2 — NF3 mixtures. The conditions for obtaining effective UV lasing with a laser pulse width of more than 50 ns at the base level are determined. A possibility of depopulating the lower level of the C3Πu — B3Πg transition by induced transitions in the first positive B3Πg — A3Σu+ system is shown; this process makes it possible to expand the pulse to 100 ns at λ = 337.1 nm. The highest lasing energy and power in the IR and UV spectral ranges are obtained for nitrogen lasers with spark preionisation.

  17. Effects of elevated carbon dioxide and nitrogen addition on foliar stoichiometry of nitrogen and phosphorus of five tree species in subtropical model forest ecosystems

    International Nuclear Information System (INIS)

    The effects of elevated carbon dioxide (CO2) and nitrogen (N) addition on foliar N and phosphorus (P) stoichiometry were investigated in five native tree species (four non-N2 fixers and one N2 fixer) in open-top chambers in southern China from 2005 to 2009. The high foliar N:P ratios induced by high foliar N and low foliar P indicate that plants may be more limited by P than by N. The changes in foliar N:P ratios were largely determined by P dynamics rather than N under both elevated CO2 and N addition. Foliar N:P ratios in the non-N2 fixers showed some negative responses to elevated CO2, while N addition reduced foliar N:P ratios in the N2 fixer. The results suggest that N addition would facilitate the N2 fixer rather than the non-N2 fixers to regulate the stoichiometric balance under elevated CO2. - Highlights: ► Five native tree species in southern China were more limited by P than by N. ► Shifts in foliar N:P ratios were driven by P dynamic under the global change. ► N addition lowered foliar N:P ratios in the N2 fixer under elevated CO2. - N addition could facilitate the N2 fixer rather than the non-N2 fixers to regulate foliar N and P stoichiometry under elevated CO2 in subtropical forests.

  18. Multiplicative and Additive Modulation of Neuronal Tuning with Population Activity Affects Encoded Information.

    Science.gov (United States)

    Arandia-Romero, Iñigo; Tanabe, Seiji; Drugowitsch, Jan; Kohn, Adam; Moreno-Bote, Rubén

    2016-03-16

    Numerous studies have shown that neuronal responses are modulated by stimulus properties and also by the state of the local network. However, little is known about how activity fluctuations of neuronal populations modulate the sensory tuning of cells and affect their encoded information. We found that fluctuations in ongoing and stimulus-evoked population activity in primate visual cortex modulate the tuning of neurons in a multiplicative and additive manner. While distributed on a continuum, neurons with stronger multiplicative effects tended to have less additive modulation and vice versa. The information encoded by multiplicatively modulated neurons increased with greater population activity, while that of additively modulated neurons decreased. These effects offset each other so that population activity had little effect on total information. Our results thus suggest that intrinsic activity fluctuations may act as a "traffic light" that determines which subset of neurons is most informative. PMID:26924437

  19. Response of Kobresia pygmaea and Stipa purpurea Grassland Communities in Northern Tibet to Nitrogen and Phosphate Addition

    Directory of Open Access Journals (Sweden)

    Jingsheng Wang

    2015-02-01

    Full Text Available The Tibetan Plateau is of fundamental ecological significance to China, Asia, and the world. In recent years, Tibetan grasslands have suffered from severe degradation due to climate change and anthropogenic disturbance. In this study, nitrogen (N and phosphate were applied to a moderately degraded Kobresia pygmaea meadow and Stipa purpurea steppe in the arid alpine northern Tibetan Plateau. The results showed that with increasing nitrogenous fertilizer, the height, coverage, biomass, and importance value of the K. pygmaea population decreased whereas the population of S. purpurea exhibited the opposite trend. Application of a mixed fertilizer with the same amount of N and phosphorus (P (5 g each per m2 doubled the biomass of the K. pygmaea meadow and increased the aboveground biomass of the S. purpurea steppe by 72.3%. The nitrogenous fertilizer increased the total biomass and belowground biomass of the S. purpurea steppe, whereas the mixed fertilizer was beneficial to aboveground grass recovery. Application of 10 g N + 5 g P m−2 fertilizer increased aboveground biomass by 164.8%, whereas the belowground biomass was less than the control by 4.7%. The N and P fertilizer did not affect soil pH, except for some changes in soil N and P contents.

  20. Nonlinear responses to nitrogen and strong interactions with nitrogen and phosphorus additions drastically alter the structure and function of a high arctic ecosystem

    Science.gov (United States)

    Arens, Seth J. T.; Sullivan, Patrick F.; Welker, Jeffrey M.

    2008-09-01

    Significant changes in ecosystem CO2 exchange and vegetation characteristics were observed following multiple additions of nitrogen (N) and factorial additions of N and phosphorus (P) to prostrate dwarf-shrub, herb tundra in Northwest Greenland. Ecosystem CO2 exchange and vegetation cover and composition were very sensitive to low rates of N inputs (0.5 g m-2 y-1), indicating that even low rates of atmospheric N deposition may alter high arctic ecosystem structure and function. Increasing N addition from 1 to 5 g N m-2 y-1 did not alter CO2 exchange or vegetation characteristics, suggesting the ecosystem had become N saturated. Factorial additions of both N and P released the ecosystem from N saturation and dramatically increased gross ecosystem photosynthesis (+500%) and ecosystem respiration (+250%), such that the ecosystem switched from a small source of CO2 to a small sink for CO2 at midday during the 2005 growing season. Changes in the component fluxes of CO2 exchange were largely explained by a doubling of the normalized difference vegetation index, a 100% increase in vascular plant cover and dramatic increases in the abundance of several previously rare grass species. Our results clearly demonstrate that high arctic prostrate dwarf-shrub, herb tundra is highly sensitive to low levels of N addition and that future increases in N deposition or N mineralization will likely lead to change in carbon cycling and vegetation characteristics, but the magnitude of the response will be constrained by P availability.

  1. Hexachlorobenzene dechlorination as affected by nitrogen application in acidic paddy soil

    International Nuclear Information System (INIS)

    Batch incubation experiments were conducted to study the effects of different nitrogen (N) fertilizers (NH4HCO3, CO(NH2)2, and NaNO3) on hexachlorobenzene (HCB) dechlorination in an acidic paddy soil. Results showed that NH4HCO3 and CO(NH2)2 had similar effects on HCB dechlorination, and their application amount was a crucial factor on reductive dechlorination. The addition of a proper amount of 0.14 g NH4HCO3- or CO(NH2)2-N to 500 g soil promoted HCB dechlorination, however, the application of a high amount (0.84 g) of NH4HCO3- or CO(NH2)2-N inhibited HCB dechlorination. Additional NaNO3 served as an electron acceptor and led to lower soil pH, thus inhibited HCB dechlorination. Detected dechlorinated products showed that the dominant pathway of HCB dechlorination was HCB → pentachlorobenzene (PeCB) → 1,2,3,5-tetrachlorobenzene (TeCB) → 1,3,5-trichlorobenzene (TCB), and PeCB was the main metabolite. The role of methanogenic bacteria in HCB dechlorination was uncertain and conditions-dependent.

  2. Nitrogen metabolism of young barley plants as affected by NaCl - salinity and potassium

    International Nuclear Information System (INIS)

    In a solution culture experiment with 31 days old barley plants (var. Miura) the influence of NaCl-salinization (80 mM) and KCl addition (5 and 10 mM) on the uptake and turnover of labelled nitrogen (15NH415NO3) was studied. Labelled N was applied for 24h at the end of a 20 days salinization period. Salinization impaired growth and incorporation of labelled N into the protein fraction paralleled by accumulation of labelled inorganic N. All salt effects were much more pronounced in the shoots than in the roots. Potassium addition enhanced N uptake (total 15N-content) and incorporation into protein, reduced the accumulation of inorganic N and improved the growth of salinized plants. The presented data support the point of view that impairment of protein (enzyme) metabolism is an important aspect of salt stress which is probably induced by the disturbance of the K/Na balance of the tissues under saline conditions. (Auth.)

  3. Dynamic Regulation of Nitrogen and Organic Acid Metabolism of Cherry Tomato Fruit as Affected by Different Nitrogen Forms

    Institute of Scientific and Technical Information of China (English)

    XU Xin-Juan; LI Qing-Yu; SONG Xiao-Hui; Shen Qi-Rong; Dong Cai-Xia

    2012-01-01

    Cherry tomatoes (Lycopersicon esculentum Mill.,cv.hongyangli) were hydroponically cultivated in a greenhouse to determine the effect of different nitrogen (N) forms on organic acid concentration and the activities of related enzymes involved in nitrogen and organic acid metabolism during cherry tomato fruit development.The results showed that fruit nitrate reductase (NR) activity was much higher following treatment with 100% NO-3 and 75% NO-3 +25% NH+4 than with 100% NH+4 except at maturity.Glutamine synthetaee (GS) activity trended downward during fruit development under all three treatments.Plants fed 100% NH4+ had the lowest fruit citrate and malate levels at maturity,with the highest malate concentration at an early stage.The activity of phosphoenolpyruvate carboxylase (PEPC) was found to be in accord with the malate concentration with every N source.Under all three N forms,the citrate synthase (CS) activity peaked one week before the citrate concentration.

  4. Remobilization of Dry Matter, Nitrogen and Phosphorus in Durum Wheat as Affected by Genotype and Environment

    Directory of Open Access Journals (Sweden)

    Alessandro Masoni

    2007-09-01

    Full Text Available Field studies were carried out to determine dry matter (DM, nitrogen (N and phosphorus (P assimilation until anthesis and DM, N and P remobilization during grain filling in wheat. Twentyfive durum wheat (Triticum durum L. varieties were grown in Tuscany at Grosseto and at Arezzo. At Grosseto 76% of DM was assimilated during pre-anthesis while at Arezzo the amount was 81%. At Grosseto 44% and at Arezzo 35% of N was accumulated until anthesis, while 33% of P was stored until anthesis in both localities. Cultivar differences in DM and N remobilization were positively related to pre-anthesis dry matter and N content at anthesis (r > 0.74. Environmental contraints on carbon, N and P availability in the plant are crucial factors in determining grain yield and N and P content in grain, affecting both accumulation and remobilization. In the low rainfall site of Grosseto, most of the grain yield originated from dry matter accumulation, while in the wetter environment of Arezzo remobilization and accumulation contributed equally to grain yield. Conversely, at Grosseto grain N content relied most on remobilization and at Arezzo remobilization and accumulation contributed equally. Finally, at Grosseto and at Arezzo accumulation of P was the main source of grain P content.

  5. Fungal endophyte Phomopsis liquidambari affects nitrogen transformation processes and related microorganisms in the rice rhizosphere

    Directory of Open Access Journals (Sweden)

    Bo eYang

    2015-09-01

    Full Text Available The endophytic fungus Phomopsis liquidambari performs an important ecosystem service by assisting its host with acquiring soil nitrogen (N, but little is known regarding how this fungus influences soil N nutrient properties and microbial communities. In this study, we investigated the impact of P. liquidambari on N dynamics,the abundance and composition of N cycling genes in rhizosphere soil treated with three levels of N (urea. Ammonia-oxidizing archaea (AOA, ammonia-oxidizing bacteria (AOB and diazotrophs were assayed using quantitative real-time polymerase chain reaction and denaturing gradient gel electrophoresis at four rice growing stages (S0: before planting, S1: tillering stage, S2: grain filling stage, and S3: ripening stage. A significant increase in the available nitrate and ammonium contents was found in the rhizosphere soil of endophyte-infected rice under low N conditions. Moreover, P. liquidambari significantly increased the potential nitrification rates (PNR, affected the abundance and community structure of AOA, AOB and diazotrophs under low N conditions in the S1 and S2 stages. The root exudates were determined due to their important role in rhizosphere interactions. P. liquidambari colonization altered the exudation of organic compounds by rice roots and P. liquidambari increased the concentration of soluble saccharides, total free amino acids and organic acids

  6. Parameters affecting nitrogen oxides in a Coal-Fired Flow Facility system

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Xiaoliang

    1996-03-01

    The unusually high temperature in the primary combustor of the Coal-Fired Magnetohydrodynamics (MHD) power generation system causes much higher nitrogen oxides (NO{sub x}) to be produced than in a conventional coal fired generation system. In order to lower the NO{sub x} concentration to an acceptable level, it is important to know how parameters of the MM power generation system affect the NO{sub x} concentration. This thesis investigates those effects in the Coal-Fired Flow Facility (CFFF) at the University of Tennessee Space Institute under the contract of US Department Of Energy (DOE). With thermodynamic and kinetic computer codes, the theoretical studies were carried out on the parameters of the CFFF system. The results gathered from the computer codes were analyzed and compared with the experimental data collected during the LMF5J test. The thermodynamic and kinetic codes together modeled the NO.{sub x} behavior with reasonable accuracy while some inconsistencies happened at the secondary combustor inlet.

  7. Changes in the salinity tolerance of sweet pepper plants as affected by nitrogen form and high CO2 concentration.

    Science.gov (United States)

    Piñero, María C; Pérez-Jiménez, Margarita; López-Marín, Josefa; Del Amor, Francisco M

    2016-08-01

    The assimilation and availability of nitrogen in its different forms can significantly affect the response of primary productivity under the current atmospheric alteration and soil degradation. An elevated CO2 concentration (e[CO2]) triggers changes in the efficiency and efficacy of photosynthetic processes, water use and product yield, the plant response to stress being altered with respect to ambient CO2 conditions (a[CO2]). Additionally, NH4(+) has been related to improved plant responses to stress, considering both energy efficiency in N-assimilation and the overcoming of the inhibition of photorespiration at e[CO2]. Therefore, the aim of this work was to determine the response of sweet pepper plants (Capsicum annuum L.) receiving an additional supply of NH4(+) (90/10 NO3(-)/NH4(+)) to salinity stress (60mM NaCl) under a[CO2] (400μmolmol(-1)) or e[CO2] (800μmolmol(-1)). Salt-stressed plants grown at e[CO2] showed DW accumulation similar to that of the non-stressed plants at a[CO2]. The supply of NH4(+) reduced growth at e[CO2] when salinity was imposed. Moreover, NH4(+) differentially affected the stomatal conductance and water use efficiency and the leaf Cl(-), K(+), and Na(+) concentrations, but the extent of the effects was influenced by the [CO2]. An antioxidant-related response was prompted by salinity, the total phenolics and proline concentrations being reduced by NH4(+) at e[CO2]. Our results show that the effect of NH4(+) on plant salinity tolerance should be globally re-evaluated as e[CO2] can significantly alter the response, when compared with previous studies at a[CO2]. PMID:27317970

  8. Wheat productivity in sandy soil as affected by plant residues, irrigation and nitrogen rates using nuclear techniques

    International Nuclear Information System (INIS)

    Increasing population in Egypt is becoming a major problem for agricultural production. The Egyptian Government must manage to increase the land productivity quickly and at low coasts. The best way to increase land productivity is the addition of organic matter to the sandy soils, to reduce the losses of water and fertilizers. The use of organic matter is considered as a good tool for maximizing soil fertility. Most of the farmers are interested with the effective use of crop residues and other recycled organic materials. The role of plant residues in modern agricultural systems has become a topic of major interest for the scientific research and agricultural authorities through improving water use efficiency. It could be concluded that the main and most effective factor affecting soil fertility, especially in sandy soils, is the organic matter content. So the main objective of the present work is to study the impact of the application of crop residues, as a source of organic matter, to sandy soils, with different nitrogen and water levels, for maximizing the input use efficiency and as well the output of wheat yield. Two field experiments were conducted at the Experimental Farm of Inshas, Nuclear Research Center, Atomic Energy Authority through 1997/1998 and 1998/1999 growing seasons. Wheat (Triticum aestivum L.) c.v. Sakha-69 was cultivated on a sandy soil to investigate: 1- the effect of different plant residues, i.e., corn ash and casourina leaves applied to sandy soils, at the rate of 10 t Fed-1, in a circle lines, 30 cm depth and 60 cm apart around the irrigation system (sprinkler); 2- two different irrigation levels namely, irrigation after 50 and 70% loss of the soil water holding capacity (SWHC) and with irrigation based on moisture depletion as measured by the Neutron Moisture Gauge; 3- two nitrogen rates as ammonium sulphate, i.e., 60 and 120 kg N /Fed, as well as the control. Nitrogen was applied in five equal splitting doses, starting 15 days after

  9. The effect of nitrogen addition on biomass production and competition in three expansive tall grasses

    International Nuclear Information System (INIS)

    A large increase of grasses Calamagrostis epigejos, Bromus inermis and Brachypodium pinnatum has often been observed in many regions enriched by higher nitrogen (N) wet deposition inputs. Competitive relationships between these grasses under enhanced N loads have not yet been studied. Therefore an outdoor experiment was established which involved monocultures of Calamagrostis, Bromus and Brachypodium and their 1:1 mixtures in containers under two N treatments, i.e., unfertilized and fertilized (+50 kg N ha−1). In monocultures, the total aboveground biomass of Calamagrostis, Bromus and Brachypodium were 1.1, 3.6 and 2.5 times higher respectively due to enhanced N fertilization. Relative crowding and aggressivity coefficients indicate that Calamagrostis and Bromus dominate when mixed with Brachypodium at both levels of N availability. When mixed with Bromus, Calamagrostis is the poorer competitor at lower N loads, however, it can be dominating in N fertilized treatments. - Highlights: ► A large increase of tall grasses has often been observed in many ecosystems. ► Data on competitive relationships between grasses were investigated. ► Competition indices indicate that Calamagrostis and Bromus dominate in mixtures with Brachypodium. ► Calamagrostis is a better competitor when mixed with Bromus but only at higher N loads. ► N deposition may play a critical role in the expansion and persistence of grasses in the landscape. - Competition abilities of Calamagrostis and Bromus were greater than Brachypodium and the competitive superiority of Calamagrostis to Bromus was in N rich substrate.

  10. Growth and sporulation of Trichoderma polysporum on organic substrates by addition of carbon and nitrogen sources

    International Nuclear Information System (INIS)

    During the present study nine different organic substrates viz., rice grains, sorghum grains, wheat grains, millet grains, wheat straw, rice husk, cow dung, sawdust and poultry manure were used for mass multiplication of Trichoderma polysporum. Grains, especially sorghum grains were found to be the best substrate for T. polysporum. Wheat straw and rice husk were less suitable, whereas, cow dung, sawdust and poultry manure were not suitable for growth of the fungus. Sucrose at the rate of 30,000 ppm and ammonium nitrate at the rate of 3,000 ppm were found to be the best carbon and nitrogen sources for growth and sporulation of T. polysporum. Amendment of the selected C and N sources to wheat straw, rice husk and millet grains resulted in significantly higher growth and conidia production by T. polysporum as compared to un-amended substrates. Sorghum and rice grains showed suppression in growth and sporulation of T. polysporum when amended with C and N sources. During studies on shelf life, populations of T. polysporum attained the peck at 60-135 days intervals on different substrates and declined gradually thereafter. However, even after 330 days, the populations were greater than the population at 0-day. At 345-360 days interval, populations were less than the initial populations at 0- days. Shelf life on C+N amended wheat straw and rice husk were more as compared to un-amended substrates. (author)

  11. The ANAMMOX reactor under transient-state conditions: process stability with fluctuations of the nitrogen concentration, inflow rate, pH and sodium chloride addition.

    Science.gov (United States)

    Yu, Jin-Jin; Jin, Ren-Cun

    2012-09-01

    The process stability of an anaerobic ammonium oxidation (ANAMMOX) was investigated in an upflow anaerobic sludge blanket reactor subjected to overloads of 2.0- to 3.0-fold increases in substrate concentrations, inflow rates lasting 12 or 24h, extreme pH levels of 4 and 10 for 12h and a 12-h 30 g l(-1) NaCl addition. During the overloads, the nitrogen removal rate improved, and the shock period was an important factor affecting the reactor performance. In the high pH condition, the reactor performance significantly degenerated; while in the low pH condition, it did not happen. The NaCl addition caused the most serious deterioration in the reactor, which took 108 h to recover and was accompanied by a stoichiometric ratio divergence. There are well correlations between the total nitrogen and the electrical conductivity which is considered to be a convenient signal for controlling and monitoring the ANAMMOX process under transient-state conditions. PMID:22728197

  12. Analysis of the influence of helium additions on the laser output and stability of a TEA nitrogen laser

    International Nuclear Information System (INIS)

    An experimental method to study the laser output and stability of a small TEA nitrogen laser is presented. The method is based on the amplitude analysis of the fluorescence produced by the interaction of the laser ultraviolet radiation with a yellow filter. Using this method, the influence of helium additions on the laser output energy and stability is analyzed. The experimental data shows that in our conditions, the higher laser output energy and stability are reached when the He presents the 45 % of the gas mixture coinciding with the helium concentration for which a spark-free laser discharge is produced. (Author)

  13. Application technique affects the potential of mineral concentrates from livestock manure to replace inorganic nitrogen fertilizer

    NARCIS (Netherlands)

    Klop, G.; Velthof, G.L.; Groenigen, van J.W.

    2012-01-01

    It has been suggested that mineral concentrates (MCs) produced from livestock manure might partly replace inorganic N fertilizers, thereby further closing the nitrogen (N) cycle. Here, we quantified nitrogen use efficiency (NUE) and N loss pathways associated with MCs, compared with inorganic fertil

  14. The impact of four decades of annual nitrogen addition on dissolved organic matter in a boreal forest soil

    Directory of Open Access Journals (Sweden)

    M. O. Rappe-George

    2012-09-01

    Full Text Available Addition of mineral nitrogen (N can alter the concentration and quality of dissolved organic matter (DOM in forest soils. The aim of this study was to assess the effect of long-term mineral N addition on soil solution concentration of dissolved organic carbon (DOC and dissolved organic nitrogen (DON in the Stråsan experimental forest (Norway spruce in Central Sweden. N was added yearly at two levels of intensity and duration: the N1 treatment represented a lower intensity, but a longer duration (43 yr of N addition than the shorter N2 treatment (24 yr. N additions were terminated in the N2 treatment in 1991. The N treatments began in 1967 when the spruce stands were 9 yr old. Soil solution in the forest floor O, and soil mineral B, horizons were sampled during the growing seasons of 1995 and 2009. Tension and non-tension lysimeters were installed in the O horizon (n=6 and tension lysimeters were installed in the underlying B horizon (n=4: soil solution was sampled at two-week intervals. Although tree growth and O horizon carbon (C and N stock increased in treatments N1 and N2, the concentration of DOC in O horizon leachates was similar in both N treatments and control. This suggests an inhibitory direct effect of N addition on O horizon DOC. Elevated DON and nitrate in O horizon leachates in the ongoing N1 treatment indicated a move towards N saturation. In B-horizon leachates, the N1 treatment approximately doubled leachate concentration of DOC and DON. DON returned to control levels but DOC remained elevated in B-horizon leachates in N2 plots 19 yr after termination of N addition. Increased aromaticity of the sampled DOM in mineral B horizon in both the ongoing and terminated N treatment indicated that old SOM in the mineral soil was a source of the increased DOC.

  15. Differences in physiological age affect diagnosis of nitrogen deficiencies in cornfields

    Institute of Scientific and Technical Information of China (English)

    J.ZHANG; A.M.BLACKMER; T.M.BLACKMER

    2008-01-01

    Many studies have shown that chlorophyll meter readings (CMRs) can be used to diagnose deficiencies of nitrogen (N) during the growth of corn (Zea mays L.) in small-plot trials,but there is need to address additional problems encountered when diagnoses are made in fields of the size managed in production agriculture.A noteworthy difference between smallplot trials and production agriculture is the extent to which the effects of N are confounded with the effects of other factors such as tillage,landscape,soil organic matter and moisture content.We illustrate how some of these factors can cause differences in the physiological age of plants and introduce errors in the diagnoses of N deficiencies.We suggest methods (measuring the height to the youngest leaf collar and assigning leaf numbers by using the first leaf with pubescence and the ear leaf as references to identify growth stages) for minimizing these errors.The simplified method of growth stage identification can be used to select appropriate plants and leaves for making diagnoses in fields and to distinguish the effects of N from the effects of other factors that influence plant growth.

  16. Biodegradation study of crop residues as affected by exogenous inorganic nitrogen and fungal inoculants.

    Science.gov (United States)

    Gaind, Sunita; Pandey, Alok Kumar; Lata

    2005-01-01

    The comparative decomposition of chickpea residue, and chopped and unchopped wheat straw was investigated in pits for 120 days. Microbial biomass, humus, C/N ratio, pH, Electrical conductivity (EC), dehydrogenase, alkaline phosphatase, cellulase, xylanase, total phenol and soluble protein were determined to assess their response to the addition of inorganic nitrogen and mixed fungal inoculum of Aspergillus nidulans, Phanerochaete chrysosporium and Trichoderma viride. The evaluation of physico-chemical parameters (organic matter, organic carbon, N, C/N, pH, EC, microbial biomass) revealed that by supplementing unchopped wheat straw with 1% urea and mixed fungal inoculum, a lowest C/N ratio of 10.7, lowest biomass of 9.54 and highest humus content of 13% can be achieved within 3 months. Germination of Lepidium sativum (cress seeds) showed a germination index >60%, in this treatment. The enzyme assay for dehydrogenase indicated highest microbial activity in uninoculated treatments compared to fungal inoculated counterparts, in the second month sampling (active phase of composting). However, cellulase and xylanase activity showed an upward trend during curing phase of composting. Chickpea residue compost, though resulted in a C/N ratio of 17.3, but its germination index was less than 60%. The rapid quality tests conducted for H2S, NH3, NO3 and starch confirmed the stability and maturity of finished compost prepared from wheat straw through microbial inoculants. PMID:16028202

  17. Grain, milling, and head rice yields as affected by nitrogen rate and bio-fertilizer application

    Directory of Open Access Journals (Sweden)

    Saeed FIROUZI

    2015-11-01

    Full Text Available To evaluate the effects of nitrogen rate and bio-fertilizer application on grain, milling, and head rice yields, a field experiment was conducted at Rice Research Station of Tonekabon, Iran, in 2013. The experimental design was a factorial treatment arrangement in a randomized complete block with three replicates. Factors were three N rates (0, 75, and 150 kg ha-1 and two bio-fertilizer applications (inoculation and uninoculation with Nitroxin, a liquid bio-fertilizer containing Azospirillum spp. and Azotobacter spp. bacteria. Analysis of variance showed that rice grain yield, panicle number per m2, grain number per panicle, flag leaves area, biological yield, grains N concentration and uptake, grain protein concentration, and head rice yield were significantly affected by N rate, while bio-fertilizer application had significant effect on rice grain yield, grain number per panicle, flag leaves area, biological yield, harvest index, grains N concentration and uptake, and grain protein concentration. Results showed that regardless of bio-fertilizer application, rice grain and biological yields were significantly increased as N application rate increased from 0 to 75 kg ha-1, but did not significantly increase at the higher N rate (150 kg ha-1. Grain yield was significantly increased following bio-fertilizer application when averaged across N rates. Grains N concentration and uptake were significantly increased as N rate increased up to 75 kg ha-1, but further increases in N rate had no significant effect on these traits. Bio-fertilizer application increased significantly grains N concentration and uptake, when averaged across N rates. Regardless of bio-fertilizer application, head rice yield was significantly increased from 56 % to 60 % when N rate increased from 0 to 150 kg ha-1. Therefore, this experiment illustrated that rice grain and head yields increased with increasing N rate, while bio-fertilizer application increased only rice grain

  18. Fermentation Quality of Ensiled Water Hyacinth (Eichhornia crassipes) as Affected by Additives.

    Science.gov (United States)

    Tham, Ho Thanh; Van Man, Ngo; Pauly, Thomas

    2013-02-01

    A lab-scale ensiling study was carried out to investigate the fermentation quality of water hyacinth (WH) supplemented with molasses, rice bran, as an absorbent, and an inoculant in the form of fermented vegetable juice and their combinations. After wilting the water hyacinths for 7 h to a dry matter (DM) content of 240 to 250 g/kg, the following treatments were applied: i) Control (C), WH only; ii) WH with sugarcane molasses at 40 g/kg WH (CM); iii) WH inoculated with fermented vegetable juice at 10 ml/kg WH (CI); iv) CM and CI (CMI) combined; v) WH with 150 g rice bran/kg WH (CA); vi) CA and CI combined (CAI); vii) CA and CM combined (CAM); and viii) CA, CM and CI combined (CAMI). After application of additives, the differently treated forages were mixed and ensiled in triplicates in 1,500-ml polyethylene jars. After ensiling for 3 d, pH values in all treatments, except C and CI, had decreased to approximately 4.0 and remained low till 14 d. After 56 d, pH had increased between 0.4 to 0.9 pH-units compared to those at 14 d. The ammonia nitrogen (NH3-N) concentration ranged from an acceptable level in treatment CM (8 g/kg N) to a high NH3-N value in treatment CMI (16 g/kg N). Lactic acid formation was higher in CI than in all other treatments. Butyric acid contents, which indicate badly fermented silages, were low in all silages (<2 g/kg DM). There were two-way interactions (p-values from <0.001 to 0.045) for almost all fermentation end-products and pH, except for the molasses×inoculant interaction on NH3-N (p = 0.26). Significant 3-way interactions were found on all observed variables except for weight losses of silages. It is concluded that conserving wilted WH as silage for ruminants may be improved by the addition of molasses or rice bran. PMID:25049776

  19. Effects of Nitrogen Addition on Litter Decomposition and CO2 Release: Considering Changes in Litter Quantity

    Science.gov (United States)

    Li, Hui-Chao; Hu, Ya-Lin; Mao, Rong; Zhao, Qiong; Zeng, De-Hui

    2015-01-01

    This study aims to evaluate the impacts of changes in litter quantity under simulated N deposition on litter decomposition, CO2 release, and soil C loss potential in a larch plantation in Northeast China. We conducted a laboratory incubation experiment using soil and litter collected from control and N addition (100 kg ha−1 year−1 for 10 years) plots. Different quantities of litter (0, 1, 2 and 4 g) were placed on 150 g soils collected from the same plots and incubated in microcosms for 270 days. We found that increased litter input strongly stimulated litter decomposition rate and CO2 release in both control and N fertilization microcosms, though reduced soil microbial biomass C (MBC) and dissolved inorganic N (DIN) concentration. Carbon input (C loss from litter decomposition) and carbon output (the cumulative C loss due to respiration) elevated with increasing litter input in both control and N fertilization microcosms. However, soil C loss potentials (C output–C input) reduced by 62% in control microcosms and 111% in N fertilization microcosms when litter addition increased from 1 g to 4 g, respectively. Our results indicated that increased litter input had a potential to suppress soil organic C loss especially for N addition plots. PMID:26657180

  20. Response of dissolved carbon and nitrogen concentrations to moderate nutrient additions in a tropical montane forest of south Ecuador

    Science.gov (United States)

    Velescu, Andre; Valarezo, Carlos; Wilcke, Wolfgang

    2016-05-01

    In the past two decades, the tropical montane rain forests in south Ecuador experienced increasing deposition of reactive nitrogen mainly originating from Amazonian forest fires, while Saharan dust inputs episodically increased deposition of base metals. Increasing air temperature and unevenly distributed rainfall have allowed for longer dry spells in a perhumid ecosystem. This might have favored mineralization of dissolved organic matter (DOM) by microorganisms and increased nutrient release from the organic layer. Environmental change is expected to impact the functioning of this ecosystem belonging to the biodiversity hotspots of the Earth. In 2007, we established a nutrient manipulation experiment (NUMEX) to understand the response of the ecosystem to moderately increased nutrient inputs. Since 2008, we have continuously applied 50 kg ha-1 a-1 of nitrogen (N), 10 kg ha-1 a-1 of phosphorus (P), 50 kg + 10 kg ha-1 a-1 of N and P and 10 kg ha-1 a-1 of calcium (Ca) in a randomized block design at 2000 m a.s.l. in a natural forest on the Amazonia-exposed slopes of the south Ecuadorian Andes. Nitrogen concentrations in throughfall increased following N+P additions, while separate N amendments only increased nitrate concentrations. Total organic carbon (TOC) and dissolved organic nitrogen (DON) concentrations showed high seasonal variations in litter leachate and decreased significantly in the P and N+P treatments, but not in the N treatment. Thus, P availability plays a key role in the mineralization of DOM. TOC/DON ratios were narrower in throughfall than in litter leachate but their temporal course did not respond to nutrient amendments. Our results revealed an initially fast, positive response of the C and N cycling to nutrient additions which declined with time. TOC and DON cycling only change if N and P supply are improved concurrently, while NO3-N leaching increases only if N is separately added. This indicates co-limitation of the microorganisms by N and P

  1. Response of dissolved carbon and nitrogen concentrations to moderate nutrient additions in a tropical montane forest of south Ecuador

    Directory of Open Access Journals (Sweden)

    Andre eVelescu

    2016-05-01

    Full Text Available In the past two decades, the tropical montane rain forests in south Ecuador experienced increasing deposition of reactive nitrogen mainly originating from Amazonian forest fires, while Saharan dust inputs episodically increased deposition of base metals. Increasing air temperature and unevenly distributed rainfall have allowed for longer dry spells in a perhumid ecosystem. This might have favored mineralization of dissolved organic matter (DOM by microorganisms and increased nutrient release from the organic layer. Environmental change is expected to impact the functioning of this ecosystem belonging to the biodiversity hotspots of the Earth.In 2007, we established a nutrient manipulation experiment (NUMEX to understand the response of the ecosystem to moderately increased nutrient inputs. Since 2008, we have continuously applied 50 kg ha-1 a-1 of nitrogen (N, 10 kg ha-1 a-1 of phosphorus (P, 50 kg + 10 kg ha-1 a-1 of N and P and 10 kg ha-1 a-1 of calcium (Ca in a randomized block design at 2000 m a.s.l. in a natural forest on the Amazonia-exposed slopes of the south Ecuadorian Andes.Nitrogen concentrations in throughfall increased following N+P additions, while separate N amendments only increased nitrate concentrations. Total organic carbon (TOC and dissolved organic nitrogen (DON concentrations showed high seasonal variations in litter leachate and decreased significantly in the P and N+P treatments, but not in the N treatment. Thus, P availability plays a key role in the mineralization of DOM. TOC/DON ratios were narrower in throughfall than in litter leachate but their temporal course did not respond to nutrient amendments.Our results revealed an initially fast, positive response of the C and N cycling to nutrient additions which declined with time. TOC and DON cycling only change if N and P supply are improved concurrently, while NO3-N leaching increases only if N is separately added. This indicates co-limitation of the microorganisms by N

  2. Growth and Nitrogen Uptake in Sorghum Plants Manured with Leucaena Leucocaphala Leaves as Affected by Nitrogen Rate and Time of Application

    International Nuclear Information System (INIS)

    A pot experiment was conducted to determine the effect of four rates of nitrogen (N) in the form of leucaena leaves and the time of application on the performance of sorghum plants using the 15N isotopic dilution technique. Results showed that leucaena green manure (LGM) increased dry matter and N yield of sorghum. Nitrogen recoveries of LGM ranged between 23 and 47%. An additional beneficial effect of LGM was attributed to the enhancement of soil N uptake. The best timing of LGM incorporation for obtaining more N derived from LGM, less soil N uptake, and greater dry matter and N in sorghum leaves seemed to be at planting. However, the appropriate timing and rate of LGM to obtain greater dry matter and N yield in panicles, as well as in the whole plant of sorghum, appeared to be at 30 days before planting, particularly a rate of 120 kg N ha-1. (author)

  3. Utilization of nitrogen by soybean (Glycine max) influenced by the addition of sugar cane bagasse

    International Nuclear Information System (INIS)

    N2-fixation in soybean and soil-N and 15N-urea utilization where studied in a glasshouse. Doses of fertilizer were 0, 40 and 80 kgN/ha added either to cultivated - or virgin soil, where sugar cane bagasse was also added (20 ton/ha). Non-nodulating soybean was used as a control to determine the absorption of the three N-sources: soil, fertilizer and N2-fixation. The N-immobilization effect caused by bagasse addition was observed even after a pre-incubation period of 40 days, being greater in the cultivated than in the soil without organic matter. Accumulations of N, P and S where also smaller in these plants. Additions of N were not sufficient to equal the values observed in soils without organic matter. Addition of 40 kgN/ha showed a sinergistic and positive effect on treatments that had N-immobilization, reinforcing the idea that starter doses of N are necessary for maximization of nodulation and N2-fixation in soybean, in soils with low N. N2-fixation contributed with mean values of 54% and 84% N, respectively, in the aerial part and pools in non-treated soil. When bagasse was added, the percentages of N2-fixed increased, however in smaller amounts, showing a necessity of different sources of N to increase the total N in plant. The greatest N2-fixation (48,6 kgN/ha) was found in the cultivated soil, where only bagasse had been added. (M.A.)

  4. Response of wheat to additional nitrogen fertilizer application after pig slurry on over-fertilized soils

    OpenAIRE

    Guillaumes Cullell, Elisenda; Carrasco Martín, Israel; Villar Mir, Josep Ma.

    2006-01-01

    Pig slurry is a valuable nutrient resource but constitutes a waste disposal problem in areas of high animal density. In the semiarid area of Pla d’Urgell, in the Ebro Valley, North-East Spain, irrigated crops receive large amounts of nutrients in the form of manure and mineral fertilizers. We studied the effect of pig slurry and additional side-dress mineral fertilizers on irrigated wheat, Triticum aestivum L., on a coarse loam soil, with high soil P and K levels. Yields increased by 62...

  5. Effects of Nitrogen Addition on Litter Decomposition and CO2 Release: Considering Changes in Litter Quantity

    OpenAIRE

    Li, Hui-Chao; Hu, Ya-Lin; Mao, Rong; Zhao, Qiong; Zeng, De-Hui

    2015-01-01

    This study aims to evaluate the impacts of changes in litter quantity under simulated N deposition on litter decomposition, CO2 release, and soil C loss potential in a larch plantation in Northeast China. We conducted a laboratory incubation experiment using soil and litter collected from control and N addition (100 kg ha−1 year−1 for 10 years) plots. Different quantities of litter (0, 1, 2 and 4 g) were placed on 150 g soils collected from the same plots and incubated in microcosms for 270 d...

  6. Salt additions alter short-term nitrogen and carbon mobilization in a coastal Oregon Andisol.

    Science.gov (United States)

    Compton, Jana E; Church, M Robbins

    2011-01-01

    Deposition of sea salts is commonly elevated along the coast relative to inland areas, yet little is known about the effects on terrestrial ecosystem biogeochemistry. We examined the influence of NaCl concentrations on N, C, and P leaching from a coastal Oregon forest Andisol in two laboratory studies: a rapid batch extraction (approximately 1 d) and a month-long incubation using microlysimeters. In the rapid extractions, salt additions immediately mobilized significant amounts of ammonium and phosphate but not nitrate. In the month-long incubations, salt additions at concentrations in the range of coastal precipitation increased nitrate leaching from the microcosms by nearly 50% and reduced the mobility of dissolved organic carbon. Our findings suggest that coupled abiotic-biotic effects increase nitrate mobility in these soils: exchange of sodium for ammonium, then net nitrification. Changes in sea salt deposition to land and the interactions with coastal soils could alter the delivery of N and C to sensitive coastal waters. PMID:21869523

  7. How Subduction Settings can Affect Planetary Nitrogen Cycle: An Experimental Insight

    Science.gov (United States)

    Cedeno, D. G.; Conceicao, R. V.; Wilbert de Souza, M. R.; Carniel, L. C.; Schmitz Quinteiro, R. V.

    2015-12-01

    Nitrogen is one of the main building blocks of life on Earth and its elemental cycle is deeply connected with organic matter and the biological system. It is known that nitrogen can be stored in mantellic phases (such as clinopyroxenes) or in metallic alloys under high pressures, meaning that Earth's mantle, and even the core, could be efficient nitrogen reservoirs. Probably, nitrogen is present in these deep Earth systems since the formation of our planet. Nevertheless, it is possible that superficial nitrogen can be reintroduced in the mantle through tectonic processes along Earth history. This is reinforced by d15N values in inclusions in diamonds and other deep mantle phases. We believe that subduction zones are efficient enough to transport nitrogen from surface to mantle. Clay minerals with high charge exchange capacity (CEC) are good candidates to convey nitrogen in subduction zones, especially when we take into account the similarities between K+ and NH4+. To simulate the high-pressure high-temperature conditions found in subduction zones, we performed a series of experiments with montmorillonite clay mineral undergone to high pressure and high temperature produced by a hydraulic press coupled with toroidal chambers, in pressures ranging from 2.5 to 7.7 GPa and temperatures up to 700oC. We used ex situ XRD analysis to accompany the main montmorillonite structural changes and FTIR analysis to determine quantitatively the presence of nitrogen. So far, our results show that the main structural transition in montmorillonite happens at ~350oC at room pressure and ~450oC at 2.5 and 4.0 GPa and consists in the transformation of an open clay structure to a closed mica structure (tobelite). FTIR data show the presence of nitrogen in all the analysed experiments. With the data obtained, we can presume that clay minerals carried in subduction zones can successfully transport nitrogen and other volatiles to the mantle. However, only cold subduction systems have the

  8. Simulation of water and nitrogen dynamics as affected by drip fertigation strategies

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jian-jun; LI Jiu-sheng; ZHAO Bing-qiang; LI Yan-ting

    2015-01-01

    The aim of drip fertigation is synchronising the application of water and nutrients with crop requirements, and maintaining the proper concentration and distribution of nutrient and water in the soil. The wetting patterns and nutrient distributions under drip fertigation have been proved to be closely related to the fertigation strategies. In order to ifnd out the critical factors that affect the nutrient distribution under different drip fertigaiton strategies, a computer simulation model HYDRUS2D/3D was used to simulate the water and nitrate distribution for various fertigation strategies from a surface point source. Simulation results were compared with the observed ones from our previous studies. A 15° wedge-shaped plexiglass container was used in our experiment to represent one-twenty-fourth of the complete cylinder. The height of container is 40 cm, and the radius is 41 cm. The ammonium nitrate solution was added through a no. 7 needle connected to a Mariotte tube with a lfexible hose. The soil water content, nitrate and ammonium concentrations were measured. The comparison of simulated and observed data demonstrated that the model performed reliably. The numerical analysis for various fertigation strategies from a surface point source showed that: (1) The total amount of irrigation water, the concentration of the fertilizer solution and the amount of pure water used to lfush the pipeline after fertilizer solution application are the three critical factors inlfu-encing the distribution of water and fertilizer nitrogen in the soil. (2) The fresh water irrigation duration prior to fertigation has no obvious effect on nitrate distribution. The longer lfushing time period after fertigation resulted in nitrate accumulation closer to the wetting front. From the point of avoiding the possibility of nitrate loss from the root zone, we recommended that the lfushing time period should be as shorter as possible. (3) For a given amount of fertilizer, higher

  9. Effect of hydrogen addition on the deposition of titanium nitride thin films in nitrogen added argon magnetron plasma

    Science.gov (United States)

    Saikia, P.; Bhuyan, H.; Diaz-Droguett, D. E.; Guzman, F.; Mändl, S.; Saikia, B. K.; Favre, M.; Maze, J. R.; Wyndham, E.

    2016-06-01

    The properties and performance of thin films deposited by plasma assisted processes are closely related to their manufacturing techniques and processes. The objective of the current study is to investigate the modification of plasma parameters occurring during hydrogen addition in N2  +  Ar magnetron plasma used for titanium nitride thin film deposition, and to correlate the measured properties of the deposited thin film with the bulk plasma parameters of the magnetron discharge. From the Langmuir probe measurements, it was observed that the addition of hydrogen led to a decrease of electron density from 8.6 to 6.2  ×  (1014 m‑3) and a corresponding increase of electron temperature from 6.30 to 6.74 eV. The optical emission spectroscopy study reveals that with addition of hydrogen, the density of argon ions decreases. The various positive ion species involving hydrogen are found to increase with increase of hydrogen partial pressure in the chamber. The thin films deposited were characterized using standard surface diagnostic tools such as x-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry (SIMS), x-ray diffraction (XRD), Raman spectroscopy (RS), scanning electron microscopy (SEM) and energy dispersive x-ray spectroscopy (EDS). Although it was possible to deposit thin films of titanium nitride with hydrogen addition in nitrogen added argon magnetron plasma, the quality of the thin films deteriorates with higher hydrogen partial pressures.

  10. The impact of four decades of annual nitrogen addition on dissolved organic matter in a boreal forest soil

    Directory of Open Access Journals (Sweden)

    M. O. Rappe-George

    2013-03-01

    Full Text Available Addition of mineral nitrogen (N can alter the concentration and quality of dissolved organic matter (DOM in forest soils. The aim of this study was to assess the effect of long-term mineral N addition on soil solution concentration of dissolved organic carbon (DOC and dissolved organic nitrogen (DON in Stråsan experimental forest (Norway spruce in central Sweden. N was added yearly at two levels of intensity and duration: the N1 treatment represented a lower intensity but a longer duration (43 yr of N addition than the shorter N2 treatment (24 yr. N additions were terminated in the N2 treatment in 1991. The N treatments began in 1967 when the spruce stands were 9 yr old. Soil solution in the forest floor O, and soil mineral B, horizons were sampled during the growing seasons of 1995 and 2009. Tension and non-tension lysimeters were installed in the O horizon (n = 6, and tension lysimeters were installed in the underlying B horizon (n = 4: soil solution was sampled at two-week intervals. Although tree growth and O horizon carbon (C and N stock increased in treatments N1 and N2, the concentration of DOC in O horizon leachates was similar in both N treatments and control. This suggests an inhibitory direct effect of N addition on O horizon DOC. Elevated DON and nitrate in O horizon leachates in the ongoing N1 treatment indicated a move towards N saturation. In B horizon leachates, the N1 treatment approximately doubled leachate concentrations of DOC and DON. DON returned to control levels, but DOC remained elevated in B horizon leachates in N2 plots nineteen years after termination of N addition. We propose three possible explanations for the increased DOC in mineral soil: (i the result of decomposition of a larger amount of root litter, either directly producing DOC or (ii indirectly via priming of old SOM, and/or (iii a suppression of extracellular oxidative enzymes.

  11. Consistent effects of canopy vs. understory nitrogen addition on the soil exchangeable cations and microbial community in two contrasting forests.

    Science.gov (United States)

    Shi, Leilei; Zhang, Hongzhi; Liu, Tao; Zhang, Weixin; Shao, Yuanhu; Ha, Denglong; Li, Yuanqiu; Zhang, Chuangmao; Cai, Xi-An; Rao, Xingquan; Lin, Yongbiao; Zhou, Lixia; Zhao, Ping; Ye, Qing; Zou, Xiaoming; Fu, Shenglei

    2016-05-15

    Anthropogenic N deposition has been well documented to cause substantial impacts on the chemical and biological properties of forest soils. In most studies, however, atmospheric N deposition has been simulated by directly adding N to the forest floor. Such studies thus ignored the potentially significant effect of some key processes occurring in forest canopy (i.e., nitrogen retention) and may therefore have incorrectly assessed the effects of N deposition on soils. Here, we conducted an experiment that included both understory addition of N (UAN) and canopy addition of N (CAN) in two contrasting forests (temperate deciduous forest vs. subtropical evergreen forest). The goal was to determine whether the effects on soil exchangeable cations and microbial biomass differed between CAN and UAN. We found that N addition reduced pH, BS (base saturation) and exchangeable Ca and increased exchangeable Al significantly only at the temperate JGS site, and reduced the biomass of most soil microbial groups only at the subtropical SMT site. Except for soil exchangeable Mn, however, effects on soil chemical properties and soil microbial community did not significantly differ between CAN and UAN. Although biotic and abiotic soil characteristics differ significantly and the responses of both soil exchangeable cations and microbial biomass were different between the two study sites, we found no significant interactive effects between study site and N treatment approach on almost all soil properties involved in this study. In addition, N addition rate (25 vs. 50kgNha(-1)yr(-1)) did not show different effects on soil properties under both N addition approaches. These findings did not support previous prediction which expected that, by bypassing canopy effects (i.e., canopy retention and foliage fertilization), understory addition of N would overestimate the effects of N deposition on forest soil properties, at least for short time scale. PMID:26930308

  12. Responses of soil microbial communities and enzyme activities to nitrogen and phosphorus additions in Chinese fir plantations of subtropical China

    Science.gov (United States)

    Dong, W. Y.; Zhang, X. Y.; Liu, X. Y.; Fu, X. L.; Chen, F. S.; Wang, H. M.; Sun, X. M.; Wen, X. F.

    2015-09-01

    Nitrogen (N) and phosphorus (P) additions to forest ecosystems are known to influence various above-ground properties, such as plant productivity and composition, and below-ground properties, such as soil nutrient cycling. However, our understanding of how soil microbial communities and their functions respond to nutrient additions in subtropical plantations is still not complete. In this study, we added N and P to Chinese fir plantations in subtropical China to examine how nutrient additions influenced soil microbial community composition and enzyme activities. The results showed that most soil microbial properties were responsive to N and/or P additions, but responses often varied depending on the nutrient added and the quantity added. For instance, there were more than 30 % greater increases in the activities of β-glucosidase (βG) and N-acetyl-β-D-glucosaminidase (NAG) in the treatments that received nutrient additions compared to the control plot, whereas acid phosphatase (aP) activity was always higher (57 and 71 %, respectively) in the P treatment. N and P additions greatly enhanced the phospholipid fatty acids (PLFAs) abundance especially in the N2P (100 kg ha-1 yr-1 of N +50 kg ha-1 yr-1 of P) treatment; the bacterial PLFAs (bacPLFAs), fungal PLFAs (funPLFAs) and actinomycic PLFAs (actPLFAs) were about 2.5, 3 and 4 times higher, respectively, than in the CK (control). Soil enzyme activities were noticeably higher in November than in July, mainly due to seasonal differences in soil moisture content (SMC). βG or NAG activities were significantly and positively correlated with microbial PLFAs. These findings indicate that βG and NAG would be useful tools for assessing the biogeochemical transformation and metabolic activity of soil microbes. We recommend combined additions of N and P fertilizer to promote soil fertility and microbial activity in this kind of plantation.

  13. Factors affecting Safety Performance in Repair, Maintenance, Alteration, and Addition (RMAA Projects

    Directory of Open Access Journals (Sweden)

    Adnan Enshassi

    2014-11-01

    Full Text Available Repair, Maintenance, Alteration and Addition (RMAA works are playing an increasingly important role in developing countries. The accidents and fatalities records of RMAA sector in Gaza Strip have been alarmingly high; however, research in the RMAA sector remains limited. Safety of RMAA works has long been neglected because the project sizes of RMAA are small and only last for a short period of time, which make the working environment of RMAA works more difficult to control than new building works. The aim of this paper is to identify, valuate and rank the most important factors that affect safety performance and the most important causes of fatal accidents in RMAA projects. A questionnaire survey was used in this study. The results revealed that poor safety awareness of managers in maintenance firms and lack of training of RMAA workers for handling multi-tasks were the most important factors that affecting safety performance of RMAA works. The results showed that ineffectiveness of lack of training and certification of competence; immature corporate systems of firms which does not care with safety and health through RMAA works, and lack of leadership from government as a key client are the most significant causes of construction fatal accidents of RMAA projects. The results also indicated that the macro level factor is the most important category that causes fatal accidents in RMAA works. It is recommended to enhance the awareness of construction firms, project managers and workers regarding the importance of safety performance in repair and maintenance works and strengthen site monitoring and supervision system in construction firms. Safety training courses should be organized for workers and project managers in order to improve their safety culture and competence regarding safety performance through repair and maintenance works. Furthermore the RMAA subcontractors should be selected according to their good records of safety performance.

  14. Inhibition of nitrogen-fixing activity of the cyanobiont affects the localization of glutamine synthetase in hair cells of Azolla.

    Science.gov (United States)

    Uheda, Eiji; Maejima, Kazuhiro

    2009-10-15

    In the Azolla-Anabaena association, the host plant Azolla efficiently incorporates and assimilates ammonium ions that are released from the nitrogen-fixing cyanobiont, probably via glutamine synthetase (GS; EC 6.3.1.2) in hair cells, which are specialized cells protruding into the leaf cavity. In order to clarify the regulatory mechanism underlying ammonium assimilation in the Azolla-Anabaena association, Azolla plants were grown under an argon environment (Ar), in which the nitrogen-fixing activity of the cyanobiont was inhibited specifically and completely. The localization of GS in hair cells was determined by immunoelectron microscopy and quantitative analysis of immunogold labeling. Azolla plants grew healthily under Ar when nitrogen sources, such as NO(3)(-) and NH(4)(+), were provided in the growth medium. Both the number of cyanobacterial cells per leaf and the heterocyst frequency of the plants under Ar were similar to those of plants in a nitrogen environment (N(2)). In hair cells of plants grown under Ar, regardless of the type of nitrogen source provided, only weak labeling of GS was observed in the cytoplasm and in chloroplasts. In contrast, in hair cells of plants grown under N(2), abundant labeling of GS was observed in both sites. These findings indicate that specific inhibition of the nitrogen-fixing activity of the cyanobiont affects the localization of GS isoenzymes. Ammonium fixed and released by the cyanobiont could stimulate GS synthesis in hair cells. Simultaneously, the abundant GS, probably GS1, in these cells, could assimilate ammonium rapidly. PMID:19464754

  15. Effects of sewage sludge addition to Norway spruce seedlings on nitrogen availability and soil fauna in clear-cut areas.

    Science.gov (United States)

    Nieminen, Jouni K; Räisänen, Mikko

    2013-07-01

    Anaerobically digested and composted sewage sludge (CSS) has been suggested to be a slow-release fertilizer in forestry and an alternative to quick-release inorganic fertilizers. The effects of CSS with or without added carbohydrate on inorganic nitrogen availability and on soil animals were tested in two Norway spruce plantations. Half of the seedlings were individually fertilized with CSS, and the rest were left as controls. Solid sucrose was added to half of the fertilized and untreated seedlings. Soil samples were taken in the autumn in the first and the second year after the treatments. CSS increased soil NH4-N (2100%), the proportion of soil NO3-N, and the N concentration of spruce needles. CSS greatly reduced the abundances of enchytraeids, tardigrades and collembolans, but increased the proportion and abundance of bacterial-feeding nematodes irrespective of carbohydrate addition. A better stabilization method needs to be developed before CSS can be used as a forest fertilizer. PMID:23603467

  16. Insights into mechanisms governing forest carbon response to nitrogen deposition: a model–data comparison using observed responses to nitrogen addition

    Directory of Open Access Journals (Sweden)

    R. Q. Thomas

    2013-06-01

    Full Text Available In many forest ecosystems, nitrogen (N deposition enhances plant uptake of carbon dioxide, thus reducing climate warming from fossil fuel emissions. Therefore, accurately modeling how forest carbon (C sequestration responds to N deposition is critical for understanding how future changes in N availability will influence climate. Here, we use observations of forest C response to N inputs along N deposition gradients and at five temperate forest sites with fertilization experiments to test and improve a global biogeochemical model (CLM-CN 4.0. We show that the CLM-CN plant C growth response to N deposition was smaller than observed and the modeled response to N fertilization was larger than observed. A set of modifications to the CLM-CN improved the correspondence between model predictions and observational data (1 by increasing the aboveground C storage in response to historical N deposition (1850–2004 from 14 to 34 kg C per additional kg N added through deposition and (2 by decreasing the aboveground net primary productivity response to N fertilization experiments from 91 to 57 g C m−2 yr−1. Modeled growth response to N deposition was most sensitive to altering the processes that control plant N uptake and the pathways of N loss. The response to N deposition also increased with a more closed N cycle (reduced N fixation and N gas loss and decreased when prioritizing microbial over plant uptake of soil inorganic N. The net effect of all the modifications to the CLM-CN resulted in greater retention of N deposition and a greater role of synergy between N deposition and rising atmospheric CO2 as a mechanism governing increases in temperate forest primary production over the 20th century. Overall, testing models with both the response to gradual increases in N inputs over decades (N deposition and N pulse additions of N over multiple years (N fertilization allows for greater understanding of the mechanisms governing C–N coupling.

  17. Responses of secondary chemicals in sugar maple (Acer saccharum) seedlings to UV-B, springtime warming and nitrogen additions

    Energy Technology Data Exchange (ETDEWEB)

    Sager, E.P.S.; Hutchinson, T.C. [Trent Univ., Peterborough, ON (Canada). Environmental Studies

    2006-10-15

    Elevated UV-B radiation due to climatic change and ozone depletion may represent a significant springtime environmental stressor to germinating seedlings in temperate forest regions. This study aimed to determine the effects of UV-B, nitrogen (N) fertilization and climate warming on the concentrations of base cations and secondary metabolites in the foliage of sugar maple seedlings growing in acid or alkaline soils. The influence of measured flavonoids and phenolics on herbivore activity was examined, as well as the relationship between foliar concentrations of calcium (Ca); manganese (Mn); and N and the production of phenolic and flavonoid compounds. Experimental plots were established in mature hardwood forests in alkaline and acid soil locations in Bobcaygeon and Haliburton, Ontario. Pentagonal open-top chambers were used to lengthen the growing season and simulate an earlier spring. Ammonium nitrate was applied at a rate comparable with an additional deposition of 5 g N per m per year. Fertilizer was applied on 3 separate occasions. Ambient UV-B radiation was screened out with Mylar D polyester film. Sites, treatments and time of sampling had complex effects on foliar elemental chemistry, production of secondary compounds and herbivory. Foliar concentrations of individual phenols were higher in seedlings in the UV-B exclusion treatments. At both sites, removal of ambient UV-B led to increases in flavonoids and chlorogenic acid, and reduced herbivore activity. At Haliburton, ammonium nitrate fertilization led to further increases in foliar Mn. Nitrogen additions led to decreases in the concentrations of some flavonoids at both sites. It was concluded that the composition of the forest soil governs the response of seedlings when they are exposed to abiotic stressors. 63 refs., 5 tabs., 8 figs.

  18. Essential oil composition of sweet basil cultivars as affected by nitrogen and potassium fertilization

    OpenAIRE

    NURZYNSKA-WIERDAK, RENATA; BOROWSKI, Bartlomiej; DZIDA, Katarzyna

    2013-01-01

    This study was designed to find correlations between the rate of nitrogen and potassium and basil herb quality resulting from essential oil content and composition. An increase in the amount of nitrogen in the nutritional environment of the plants resulted in the enhanced accumulation of essential oil, as well as in a rise in linalool and germacrene D concentration. The present study also showed increased content of essential oil in the herb, as well as an increase of 1,8-cineole in the oil u...

  19. Factors affecting the grain-refinement of aluminum using titanium and boron additives

    International Nuclear Information System (INIS)

    The development of grain-refining techniques for the casting of aluminum, and the results achieved using additions of ternary Al--Ti--B master-alloys, are briefly described. A test procedure is given for assessing the relative effectiveness of these master-alloys, and the results are related to the various kinds of alloy treated, including those with constituents which poison the grain-refining agent. The equilibrium conditions which affect the behavior of the constituents of the grain-refined alloys are examined quantitatively from a thermodynamic viewpoint. One theory about the mechanism of nucleation of aluminum on titanium diboride is examined and found inapplicable. New data on the solubility of TiB2, ZrB2, TiC, ZrC, Cr3C2, and CrB2 in liquid aluminum are presented graphically. Practical aspects of alloy behavior in grain-refining practice are analyzed and discussed on the basis of the quantitative data

  20. Improvement of phenolic antioxidants and quality characteristics of virgin olive oil with the addition of enzymes and nitrogen during olive paste processing

    International Nuclear Information System (INIS)

    The evolution of phenolic compounds and their contribution to the quality characteristics in virgin olive oil during fruit processing was studied with the addition of a combination of various commercial enzymes containing pectinases, polygalacturonases, cellulase and β-glucanase with or without nitrogen flush. Olive fruits (Olea europaea, L.) of the cultivar Megaritiki, at the semi black pigmentation stage of maturity, were used in a 3-phase extraction system in an experiment at industrial scale. The addition of enzymes in the olive paste during processing increased the total phenol and ortho-diphenol contents, as well as some simple phenolic compounds (3,4-DHPEA, p-HPEA) and the secoiridoid derivatives (3,4-DHPEA-EDA and 3,4-DHPEAEA) in olive oil and therefore improved its oxidative stability. Furthermore, enzyme treatment ameliorated the quality parameters of the produced olive oil (acidity and peroxide value) and their sensory attributes. The use of additional N2 flush with the enzyme treatments did not improve the quality parameters of olive oil any further; however it did not affect the concentration of individual and total sterols or most of the fatty acid composition. Consequently, olive paste treatment with enzymes not only improved the quality characteristics of olive oil and enhanced the overall organoleptic quality, but also increased the olive oil yield. (Author) 33 refs.

  1. Improvement of phenolic antioxidants and quality characteristics of virgin olive oil with the addition of enzymes and nitrogen during olive paste processing

    Energy Technology Data Exchange (ETDEWEB)

    Inconomou, D.; Arapoglou, D.; Israilides, C.

    2010-07-01

    The evolution of phenolic compounds and their contribution to the quality characteristics in virgin olive oil during fruit processing was studied with the addition of a combination of various commercial enzymes containing pectinases, polygalacturonases, cellulase and {beta}-glucanase with or without nitrogen flush. Olive fruits (Olea europaea, L.) of the cultivar Megaritiki, at the semi black pigmentation stage of maturity, were used in a 3-phase extraction system in an experiment at industrial scale. The addition of enzymes in the olive paste during processing increased the total phenol and ortho-diphenol contents, as well as some simple phenolic compounds (3,4-DHPEA, p-HPEA) and the secoiridoid derivatives (3,4-DHPEA-EDA and 3,4-DHPEAEA) in olive oil and therefore improved its oxidative stability. Furthermore, enzyme treatment ameliorated the quality parameters of the produced olive oil (acidity and peroxide value) and their sensory attributes. The use of additional N{sub 2} flush with the enzyme treatments did not improve the quality parameters of olive oil any further; however it did not affect the concentration of individual and total sterols or most of the fatty acid composition. Consequently, olive paste treatment with enzymes not only improved the quality characteristics of olive oil and enhanced the overall organoleptic quality, but also increased the olive oil yield. (Author) 33 refs.

  2. Increasing shrub abundance and N addition in Arctic tundra affect leaf and root litter decomposition differently

    Science.gov (United States)

    McLaren, J.; van de Weg, M. J.; Shaver, G. R.; Gough, L.

    2013-12-01

    Changes in global climate have resulted in a ';greening' of the Arctic as the abundance of deciduous shrub species increases. Consequently, not only the living plant community, but also the litter composition changes, which in turn can affect carbon turnover patterns in the Arctic. We examined effects of changing litter composition (both root and leaf litter) on decomposition rates with a litter bag study, and specifically focused on the impact of deciduous shrub Betula nana litter on litter decomposition from two evergreen shrubs (Ledum palustre, and Vaccinium vitis-idaea) and one graminoid (Eriophorum vaginatum) species. Additionally, we investigated how decomposition was affected by nutrient availability by placing the litterbags in an ambient and a fertilized moist acidic tundra environment. Measurements were carried out seasonally over 2 years (after snow melt, mid-growing season, end growing season). We measured litter mass loss over time, as well as the respiration rates (standardized for temperature and moisture) and temperature sensitivity of litter respiration at the time of harvesting the litter bags. For leaves, Betula litter decomposed faster than the other three species, with Eriophorum leaves decomposing the slowest. This pattern was observed for both mass loss and litter respiration rates, although the differences in respiration became smaller over time. Surprisingly, combining Betula with any other species resulted in slower overall weight loss rates than would be predicted based on monoculture weight loss rates. This contrasted with litter respiration at the time of sampling, which showed a positive mixing effect of adding Betula leaf liter to the other species. Apparently, during the first winter months (September - May) Betula litter decomposition is negatively affected by mixing the species and this legacy can still be observed in the total mass loss results later in the year. For root litter there were fewer effects of species identity on root

  3. Physiological Responses of Two Epiphytic Bryophytes to Nitrogen, Phosphorus and Sulfur Addition in a Subtropical Montane Cloud Forest.

    Science.gov (United States)

    Chen, Xi; Liu, Wen-Yao; Song, Liang; Li, Su; Wu, Yi; Shi, Xian-Meng; Huang, Jun-Biao; Wu, Chuan-Sheng

    2016-01-01

    Atmospheric depositions pose significant threats to biodiversity and ecosystem function. However, the underlying physiological mechanisms are not well understood, and few studies have considered the combined effects and interactions of multiple pollutants. This in situ study explored the physiological responses of two epiphytic bryophytes to combined addition of nitrogen, phosphorus and sulfur. We investigated the electrical conductivity (EC), total chlorophyll concentration (Chl), nutrient stoichiometry and chlorophyll fluorescence signals in a subtropical montane cloud forest in south-west China. The results showed that enhanced fertilizer additions imposed detrimental effects on bryophytes, and the combined enrichment of simulated fertilization exerted limited synergistic effects in their natural environments. On the whole, EC, Chl, the effective quantum yield of photosystem II (ΦPSII) and photochemical quenching (qP) were the more reliable indicators of increased artificial fertilization. However, conclusions on nutrient stoichiometry should be drawn cautiously concerning the saturation uptake and nutrient interactions in bryophytes. Finally, we discuss the limitations of prevailing fertilization experiments and emphasize the importance of long-term data available for future investigations. PMID:27560190

  4. Effects of sewage sludge addition to Norway spruce seedlings on nitrogen availability and soil fauna in clear-cut areas

    International Nuclear Information System (INIS)

    Anaerobically digested and composted sewage sludge (CSS) has been suggested to be a slow-release fertilizer in forestry and an alternative to quick-release inorganic fertilizers. The effects of CSS with or without added carbohydrate on inorganic nitrogen availability and on soil animals were tested in two Norway spruce plantations. Half of the seedlings were individually fertilized with CSS, and the rest were left as controls. Solid sucrose was added to half of the fertilized and untreated seedlings. Soil samples were taken in the autumn in the first and the second year after the treatments. CSS increased soil NH4–N (2100%), the proportion of soil NO3–N, and the N concentration of spruce needles. CSS greatly reduced the abundances of enchytraeids, tardigrades and collembolans, but increased the proportion and abundance of bacterial-feeding nematodes irrespective of carbohydrate addition. A better stabilization method needs to be developed before CSS can be used as a forest fertilizer. -- Highlights: •Spruces were fertilized with anaerobically digested and composted sewage sludge (CSS). •CSS increased soil N, proportion of NO3–N, and N concentration of spruce needles. •CSS reduced the abundances of enchytraeids, tardigrades and collembolans. •CSS increased the proportion and abundance of bacterial-feeding nematodes. •Sucrose did not reduce N pools or counteract negative CSS effects on soil animals. -- Composting and carbohydrate addition do not mitigate the harmful effects of anaerobically digested sewage sludge in boreal forest soil

  5. Phosphorus utilization by corn as affected by green manure, nitrogen and phosphorus fertilizers

    Directory of Open Access Journals (Sweden)

    Edson Cabral da Silva

    2012-08-01

    Full Text Available The objective of this work was to evaluate the utilization by corn plants of P from triple superphosphate fertilizer labeled with 32P (32P‑TSP, and of P from soil as affected by N rates and by the green manures (GM sunn hemp (Crotalaria juncea and millet (Pennisetum glaucum. The experiment was carried out using pots filled with 5 kg Oxisol (Rhodic Hapludox. A completely randomized design was used, in a 4x4x2 factorial arrangement, with four replicates. The treatments were: four P rates as TSP (0, 0.175, 0.350, and 0.700 g P per pot; four N rates as urea (0, 0.75, 1.50, and 2.25 g N per pot; and sunn hemp or millet as green manure. The additions of N and P by the GM were taken into account. After grain physiologic maturation, corn dry matter, P contents, accumulated P, and P recovery in the different treatments were measured. 32P‑TSP recovery by corn increased with N increasing rates, and decreased with increasing rates of 32P‑TSP. The mineral fertilizer provides most of the accumulated P by corn plants. The recovery of 32P‑TSP by corn was 13.12% in average. The green manure species influence the assimilation of 32P‑TSP by the plants.

  6. Insights into mechanisms governing forest carbon response to nitrogen deposition: a model-data comparison using observed responses to nitrogen addition

    Directory of Open Access Journals (Sweden)

    R. Q. Thomas

    2013-01-01

    Full Text Available In many forest ecosystems, nitrogen (N deposition enhances plant uptake of carbon dioxide, thus reducing climate warming from fossil fuel emissions. Therefore, accurately modeling how forest carbon (C sequestration responds to N deposition is critical for understanding how future changes in N availability will influence climate. Here, we use observations of forest C response to N inputs along N deposition gradients and at five temperate forest sites with fertilization experiments to test and improve a~global biogeochemical model (CLM-CN 4.0. We show that the CLM-CN plant C growth response to N deposition was smaller than observed and the modeled response to N fertilization was larger than observed. A set of modifications to the CLM-CN improved the correspondence between model predictions and observational data (1 by increasing the aboveground C storage in response to historical N deposition (1850–2004 from 14 to 34 kg C per additional kg N added through deposition and (2 by decreasing the aboveground net primary productivity response to N fertilization experiments from 91 to 57 g C m−2 yr−1. Modeled growth response to N deposition was most sensitive to altering the processes that control plant N uptake and the pathways of N loss. The response to N deposition also increased with a more closed N cycle (reduced N fixation and N gas loss and decreased when prioritizing microbial over plant uptake of soil inorganic N. The net effect of all the modifications to the CLM-CN resulted in greater retention of N deposition and a greater role of synergy between N deposition and rising atmospheric CO2 as a mechanism governing increases in temperate forest primary production over the 20th century. Overall, testing models with both the response to gradual increases in N inputs over decades (N deposition and N pulse additions of N over multiple years (N fertilization allows for greater understanding of the mechanisms

  7. What affects the nitrogen retention in Tatra Mountains lakes' catchments in Poland?

    Directory of Open Access Journals (Sweden)

    D. Rzychoń

    2007-09-01

    Full Text Available The study of acidification and recovery of two lakes situated in the Polish Tatra Mountains, exposed to similar deposition of acidic substances but differing in altitude, catchment morphology, hydrology, and biodiversity is presented. Measurements were performed in 1992–1996 and 2001–2005. Simultaneously, research on the atmospheric deposition was carried out. The following physical and chemical parameters in lake water and precipitation were measured: pH, conductivity (K25, Ca2+, Mg2+, Na+, K+, NH4+, SO42−, NO3, Cl and alkalinity. Distinct changes in the chemical composition of precipitation were observed over 14 years (1992–2005. During this time the sulphate concentration decreased significantly, and the concentration of hydrogen ions in precipitation decreased at an average rate of 2.23 meq/m³/yr. There was no significant change in nitrate, ammonium or total nitrogen deposition. The chemical composition of water of both lakes changed significantly and showed signs of chemical recovery with decreases in sulphate concentration and increases in acid neutralising capacity. The concentration of base cations declined. Despite the lack of clear trends in nitrogen deposition, a statistically significant drop in concentration was observed in the two lakes. A significant increase of about 15% in the retention of nitrogen compounds in both catchments occurred. An improvement in nitrogen saturation status in both catchments was observed. This probably resulted mainly from decreasing acidification and global warming which prolongs the vegetative period, changes plant species composition and increases the microbiological activity of soil.

  8. What affects the nitrogen retention in Tatra Mountains lakes' catchments in Poland?

    Directory of Open Access Journals (Sweden)

    D. Rzychoń

    2008-03-01

    Full Text Available The study of acidification and recovery of two lakes situated in the Polish Tatra Mountains, exposed to similar deposition of acidic substances but differing in altitude, catchment morphology, hydrology, and biodiversity is presented. Measurements were performed in 1992–1996 and 2001–2005. Simultaneously, research on the atmospheric deposition was carried out. The following physical and chemical parameters in lake water and precipitation were measured: pH, conductivity (K25, Ca2+, Mg2+, Na+, K+, NH4+, SO42−, NO3, Cl and alkalinity. Distinct changes in the chemical composition of precipitation were observed over 14 years (1992–2005. During this time the sulphate concentration decreased significantly, and the concentration of hydrogen ions in precipitation decreased at an average rate of 2.23 meq/m3/yr. There was no significant change in nitrate, ammonium or total nitrogen deposition. The chemical composition of water of both lakes changed significantly and showed signs of chemical recovery with decreases in sulphate concentration and increases in acid neutralising capacity. The concentration of base cations declined. Despite the lack of clear trends in nitrogen deposition, a statistically significant drop in concentration was observed in the two lakes. A significant increase of about 15% in the retention of nitrogen compounds in both catchments occurred. An improvement in nitrogen saturation status in both catchments was observed. This probably resulted mainly from decreasing acidification and global warming which prolongs the vegetative period, changes plant species composition and increases the microbiological activity of soil.

  9. Urbanization affects water and nitrogen use in the food chain in China

    OpenAIRE

    Qin, W; Ma, L.(School of Physics, Shandong University, Shandong, China); Zhang, F.S.; Oenema, O.

    2012-01-01

    ABSTRACT Urbanization and agriculture are highly coupled. However, the impacts of urbanization(e.g. transformation in urban and rural population and change in diet) on water and nitrogen (N) use remain poorly understood. The objectives of this study are to quantify water flows in the food chain of China, to analyze the complex relationship between urbanization and water and N use efficiency, and to project water and N demand in China via various scenarios, using a combination of water footpri...

  10. Dissimilatory nitrate reduction to ammonium conserves nitrogen in anthropogenically affected subtropical mangrove sediments in Southeast China.

    Science.gov (United States)

    Cao, Wenzhi; Yang, Jingxin; Li, Ying; Liu, Baoli; Wang, Feifei; Chang, Changtang

    2016-09-15

    In this study, basic sediment properties, nutrient flux, and nitrogen cycle (including denitrification, anaerobic ammonium oxidation [anammox], nitrification, and dissimilatory nitrate reduction to ammonium [DNRA]) were investigated at two sampling sites with different tree ages in the mangrove region of the Jiulong River Estuary, China. The results show that sediments at mangrove flat area have relatively strong capability to reduce NO3(-), in which the DNRA rate is relatively high (204.53±48.32μmolNm(-2)h(-1)), which is approximately 75.7-85.9% of the total NO3(-) reduction, while the denitrification and anammox rates are relatively low - only approximately 5.6-9.5% and 8.5-14.8% of the total NO3(-) reduction, respectively. Thus, in the nitrogen-enriched subtropical mangrove system, DNRA is the main pathway to reduce NO3(-), and most of the input nitrogen is conserved as NH4(+) in the system, which assures high productivity of the mangrove system. PMID:27368926

  11. Effects of Nitrogen Addition on Leaf Decomposition of Single-Species and Litter Mixture in Pinus tabulaeformis Forests

    Directory of Open Access Journals (Sweden)

    Jinsong Wang

    2015-12-01

    Full Text Available The litter decomposition process is closely correlated with nutrient cycling and the maintenance of soil fertility in the forest ecosystem. In particular, the intense environmental concern about atmospheric nitrogen (N deposition requires a better understanding of its influence on the litter decomposition process. This study examines the responses of single-species litter and litter mixture decomposition processes to N addition in Chinese pine (Pinus tabulaeformis Carr. ecosystems. Chinese pine litter, Mongolian oak (Quercus mongolica Fisch. ex Ledeb. litter, and a pine–oak mixture were selected from a plantation and a natural forest of Chinese pine. Four N addition treatments, i.e., control (N0: 0 kg N ha−1·year−1, low-N (N1: 5 kg N ha−1·year−1, medium-N (N2: 10 kg N ha−1·year−1, and high-N (N3: 15 kg N ha−1·year−1, were applied starting May 2010. In the plantation, N addition significantly stimulated the decomposition of the Chinese pine litter. In the natural forest, N addition had variable effects on the decomposition of single-species litter and the litter mixture. A stimulatory effect of the high-N treatment on the Chinese pine litter decomposition could be attributed to a decrease in the substrate C:N ratio. However, an opposite effect was found for the Mongolian oak litter decomposition. The stimulating effect of N addition on the Chinese pine litter may offset the suppressive effect on the Mongolian oak litter, resulting in a neutral effect on the litter mixture. These results suggest that the different responses in decomposition of single-species litter and the litter mixture to N addition are mainly attributed to litter chemical composition. Further investigations are required to characterize the effect of long-term high-level N addition on the litter decomposition as N deposition is likely to increase rapidly in the region where this study was conducted.

  12. Nitrogen retention across a gradient of 15N additions to an unpolluted temperate forest soil in Chile

    Science.gov (United States)

    Perakis, Steven S.; Compton, J.E.; Hedin, L.O.

    2005-01-01

    Accelerated nitrogen (N) inputs can drive nonlinear changes in N cycling, retention, and loss in forest ecosystems. Nitrogen processing in soils is critical to understanding these changes, since soils typically are the largest N sink in forests. To elucidate soil mechanisms that underlie shifts in N cycling across a wide gradient of N supply, we added 15NH415NO3 at nine treatment levels ranging in geometric sequence from 0.2 kg to 640 kg NA? ha-1A? yr-1 to an unpolluted old-growth temperate forest in southern Chile. We recovered roughly half of tracers in 0-25 cm of soil, primarily in the surface 10 cm. Low to moderate rates of N supply failed to stimulate N leaching, which suggests that most unrecovered 15N was transferred from soils to unmeasured sinks above ground. However, soil solution losses of nitrate increased sharply at inputs > 160 kg NA? ha-1A? yr-1, corresponding to a threshold of elevated soil N availability and declining 15N retention in soil. Soil organic matter (15N in soils at the highest N inputs and may explain a substantial fraction of the 'missing N' often reported in studies of fates of N inputs to forests. Contrary to expectations, N additions did not stimulate gross N cycling, potential nitrification, or ammonium oxidizer populations. Our results indicate that the nonlinearity in N retention and loss resulted directly from excessive N supply relative to sinks, independent of plant-soil-microbial feedbacks. However, N additions did induce a sharp decrease in microbial biomass C:N that is predicted by N saturation theory, and which could increase long-term N storage in soil organic matter by lowering the critical C:N ratio for net N mineralization. All measured sinks accumulated 15N tracers across the full gradient of N supply, suggesting that short-term nonlinearity in N retention resulted from saturation of uptake kinetics, not uptake capacity, in plant, soil, and microbial pools.

  13. Does temperature of charcoal creation affect subsequent mineralization of soil carbon and nitrogen?

    Science.gov (United States)

    Pelletier-Bergeron, S.; Bradley, R.; Munson, A. D.

    2012-04-01

    Forest fire is the most common form of natural disturbance of boreal forest ecosystems and has primordial influence on successional processes. This may be due in part to the pre-disturbance vegetation development stage and species composition, but these successional pathways could also vary with differences in fire behavior and consequently in fire intensity, defined as the energy released during various phases of a fire. Fire intensity may also affect soil C and N cycling by affecting the quality of the charcoal that is produced. For example, the porosity of coal tends to increase with increasing temperature at which it is produced Higher porosity would logically increase the surface area to which dissolved soil molecules, such as tannins and other phenolics, may be adsorbed. We report on a microcosm study in which mineral and organic soils were jointly incubated for eight weeks with a full factorial array of treatments that included the addition of Kalmia tannins, protein, and wood charcoal produced at five different temperatures. A fourth experimental factor comprised the physical arrangement of the material (stratified vs. mixed), designed to simulate the effect of soil scarification after fire and salvage harvest. We examined the effects of these treatments on soil C and N mineralisation and soil microbial biomass. The furnace temperature at which the charcoal was produced had a significant effect on its physico-chemical properties; increasing furnace temperatures corresponded to a significant increase in % C (P<0.001), and a significant decrease in %O (P<0.001) and %H (P<0.001). Temperature also had significant impacts on microporosity (surface area and volume). Temperature of production had no effect (P=0.1355) on soil microbial biomass. We observed a linear decreasing trend (P<0.001) in qCO2 with increasing temperature of production, which was mainly reflected in a decline in basal respiration. Finally, we found a significant interaction (P=0.010) between

  14. The Potentially Affected Fraction for Target Species: Additional data and calculations

    NARCIS (Netherlands)

    Traas TP; Luttik R; Posthumus R; ECO; CSR

    1998-01-01

    In studying the possibilities for mapping toxic pressure of contaminants (expressed as Potentially Affected Fraction, PAF) on such target species as butterflies, dragonflies, amphibians, reptiles and plants, the toxicity data available for butterflies, damselflies, dragonflies and reptiles were foun

  15. Nitrogen and Carbon Cycling in a Grassland Community Ecosystem as Affected by Elevated Atmospheric CO2

    OpenAIRE

    Torbert, H.A.; Johnson, H. B.; H. W. Polley

    2012-01-01

    Increasing global atmospheric carbon dioxide (CO2) concentration has led to concerns regarding its potential effects on terrestrial ecosystems and the long-term storage of carbon (C) and nitrogen (N) in soil. This study examined responses to elevated CO2 in a grass ecosystem invaded with a leguminous shrub Acacia farnesiana (L.) Willd (Huisache). Seedlings of Acacia along with grass species were grown for 13 months at CO2 concentrations of 385 (ambient), 690, and 980 μmol mol−1. Elevated CO2 ...

  16. Oxygen and nitrogen plasma etching of three-dimensional hydroxyapatite/chitosan scaffolds fabricated by additive manufacturing

    Science.gov (United States)

    Myung, Sung-Woon; Kim, Byung-Hoon

    2016-01-01

    Three-dimensional (3D) chitosan and hydroxyapatite (HAp)/chitosan (CH) scaffolds were fabricated by additive manufacturing, then their surfaces were etched with oxygen (O2) and nitrogen (N2) plasma. O2 and N2 plasma etching was performed to increase surface properties such as hydrophilicity, roughness, and surface chemistry on the scaffolds. After etching, hydroxyapatite was exposed on the surface of 3D HAp/CH scaffolds. The surface morphology and chemical properties were characterized by contact angle measurement, scanning electron microscopy, X-ray diffraction, and attenuated total reflection Fourier infrared spectroscopy. The cell viability of 3D chitosan scaffolds was examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The differentiation of preosteoblast cells was evaluated by alkaline phosphatase assay. The cell viability was improved by O2 and N2 plasma etching of 3D chitosan scaffolds. The present fabrication process for 3D scaffolds might be applied to a potential tool for preparing biocompatible scaffolds.

  17. Suppression of hydrogenated carbon film deposition and hydrogen isotope retention by nitrogen addition into cold remote H/D and CH4 mixture plasmas

    International Nuclear Information System (INIS)

    Control of tritium retention and its removal from the first wall of future fusion devices are one of the most crucial issues for safety and effective use for fuel. Nitrogen addition into remote edge plasmas has been considered and tested as an effective method for suppression of carbon film deposition and reduction of hydrogen isotope absorption in the deposited films. In this paper we have investigated the scavenger effects of nitrogen injected into low temperature D2/CH4 plasmas on hydrogenated carbon film growth using a small helical device. The result of the deposition shows that the key reactive particles with CN and ND(H) bonds to suppression of hydrogenated carbon film growth and hydrogen isotope absorption are much slowly generated compared with hydrocarbon particles such as CD(H)x and C2D(H)x. This may be due to the slow atomic nitrogen diffusion into hydrogenated carbon layer and the chemical equilibrium between nitrogen absorption

  18. Suppression of hydrogenated carbon film deposition and hydrogen isotope retention by nitrogen addition into cold remote H/D and CH4 mixture plasmas

    Science.gov (United States)

    Iida, K.; Notani, M.; Uesugi, Y.; Tanaka, Y.; Ishijima, T.

    2015-08-01

    Control of tritium retention and its removal from the first wall of future fusion devices are one of the most crucial issues for safety and effective use for fuel. Nitrogen addition into remote edge plasmas has been considered and tested as an effective method for suppression of carbon film deposition and reduction of hydrogen isotope absorption in the deposited films. In this paper we have investigated the scavenger effects of nitrogen injected into low temperature D2/CH4 plasmas on hydrogenated carbon film growth using a small helical device. The result of the deposition shows that the key reactive particles with CN and ND(H) bonds to suppression of hydrogenated carbon film growth and hydrogen isotope absorption are much slowly generated compared with hydrocarbon particles such as CD(H)x and C2D(H)x. This may be due to the slow atomic nitrogen diffusion into hydrogenated carbon layer and the chemical equilibrium between nitrogen absorption.

  19. Ruminal nitrogen metabolism in steers as affected by feed intake and dietary urea concentration

    International Nuclear Information System (INIS)

    Four multiple-cannulated steers (340 kg) were used in a 4 x 4 Latin square design with a 2 x 2 factorial arrangement of treatments. Steers were fed a diet of 50% ground hay and 50% concentrate at two intakes (1.4 and 2.1% of BW), with urea and 15N-enriched ammonium sulfate infused continuously into the rumen at .4 or 1.2% of diet DM. Ratios of purines and diaminopimelic acid-N to N in fluid-associated and particulate-associated bacteria and in protozoa were similar among treatments but were lower for protozoa than for bacteria. Diaminopimelic acid-N:N was higher for fluid-associated vs. particulate-associated bacteria. Enrichment of 15N was similar between bacteria among treatments and was 30% lower for protozoa. Turnover rates of 15N in bacteria, NH3N, and non-HN3N pools were faster for steers infused with 1.2 than those infused with .4% urea, indicating less efficient usage of ammonia with higher urea. A method is described to estimate the proportion of duodenal nitrogen comprising bacterial and protozoal nitrogen

  20. Does chronic nitrogen deposition during biomass growth affect atmospheric emissions from biomass burning?

    International Nuclear Information System (INIS)

    Chronic nitrogen deposition has measureable impacts on soil and plant health. We investigate burning emissions from biomass grown in areas of high and low NOx deposition. Gas and aerosol-phase emissions were measured as a function of photochemical aging in an environmental chamber at UC-Riverside. Though aerosol chemical speciation was not available, results indicate a systemic compositional difference between biomass grown in high and low deposition areas. Aerosol emissions from biomass grown in areas of high NOx deposition exhibit a lower volatility than biomass grown in a low deposition area. Furthermore, fuel elemental analysis, NOx emission rates, and aerosol particle number distributions differed significantly between the two sites. Despite the limited scale of fuels explored, there is strong evidence that the atmospheric emissions community must pay attention to the regional air quality of biomass fuels growth areas. (letter)

  1. Nitrogen inversion barriers affect the N-oxidation of tertiary alkylamines by cytochromes P450

    DEFF Research Database (Denmark)

    Rydberg, Patrik; Jørgensen, Martin S.; Jacobsen, T.A.;

    2013-01-01

    Calculations: Cytochrome P450 enzymes facilitate a number of chemically different reactions. For example, amines can be either N-dealkylated or N-oxidized, but it is complex to rationalize which of these competing reactions occurs. It is shown that the barrier for inversion of the alkylamine nitr...... nitrogen atom seems to be of vital importance for the amount of N-oxidized product formed relative to dealkylation and hydroxylation products. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.......Calculations: Cytochrome P450 enzymes facilitate a number of chemically different reactions. For example, amines can be either N-dealkylated or N-oxidized, but it is complex to rationalize which of these competing reactions occurs. It is shown that the barrier for inversion of the alkylamine...

  2. Changes in water, carbon, and nitrogen fluxes with the addition of biochar to soils: lessons learned from laboratory and greenhouse experiments

    Science.gov (United States)

    Barnes, R. T.; Gallagher, M. E.; Masiello, C. A.; Liu, Z.; Dugan, B.; Rudgers, J. A.

    2011-12-01

    The addition of biochar to agricultural soils has the potential to provide a number of ecosystem services, ranging from carbon (C) sequestration to increased soil fertility and crop production. It is estimated that 0.5 to 0.9 Pg of C yr-1 can be sequestered through the addition of biochar to soils, significantly increasing the charcoal flux to the biosphere over natural inputs from fire (0.05 to 0.20 Pg C yr-1). There remain large uncertainties about biochar mobility within the environment, making it a challenge to assess the ecosystem residence time of biochar. We conducted laboratory and greenhouse experiments to understand how soil amendment with laboratory-produced biochar changes water, C, and nitrogen (N) fluxes from soils. We used column experiments to assess how biochar amendment to three types of soils (sand, organic, clay-rich) affected hydraulic conductivity and dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) fluxes. Results varied with soil type; biochar significantly decreased the hydraulic conductivity of the sand and organic soils by a factor of 10.6 and 2.7, respectively. While not statistically significant, biochar addition increased the hydraulic conductivity of the clay-rich soil by 50% on average. The addition of biochar significantly increased the DOC fluxes from the C-poor sand and clay soils while it significantly decreased the DOC flux from the organic-rich soil. In contrast, TDN fluxes decreased with biochar additions from all soil types, though the results were not statistically significant from the clay-rich soil. These laboratory experiments suggest that changes in the hydraulic conductivity of soil due to biochar amendments could play a significant role in understanding how biochar additions to agricultural fields will change watershed C and N dynamics. We additionally conducted a 28-day greenhouse experiment with sorghum plants using a three-way factorial treatment (water availability x biochar x mycorrhizae) to

  3. A wooded riparian strip set up for nitrogen removal can affect the water flux microbial composition

    Directory of Open Access Journals (Sweden)

    Mizanur Md. Rahman

    2014-02-01

    Full Text Available This research is part of a project aimed at verifying the potential of a specifically assessed wooded riparian zone in removing excess of combined nitrogen from the Zero river flow for the reduction of nutrient input into Venice Lagoon. Specific objectives were pursued to determine seasonal fluctuations of the microbial populations from the input water to a drainage ditch, conveying back the flux into the river after passing through the soil of the wooded riparian strip. The bacterial communities were determined by combined approaches involving cultivation, microscopic methods and DNA based techniques to determine both culturable and total microbial community in water. The results indicate that the size of the bacterial population, including the culturable fraction, increases from the river to the drainage ditch especially on the warm season. The multiple approach here adopted enabled also to demonstrate that the special condition created in the buffer strip supports the development and the metabolism of the microbial community. The nature of the bacterial population, in terms of phylotypes distribution, was investigated by 16S rDNA analysis indicating that the most represented genera belong to Gamma-proteobacteria, which is known to include an exceeding number of important pathogens. In spring, the effect of the buffer strip seems to significantly reduce such a sub-population. The changes observed for the total bacterial community composition become much evident in summer, as revealed by both denaturing gradient gel electrophoresis cluster analysis and by the diversity index calculation. The hydraulic management coupled to the suspension of farming practices and the development of the woody and herbaceous vegetation resulted in a condition suitable for the containment of undesired microbiota (mainly during the spring season while continuing to support denitrification activity (especially throughout the summer as verified by the total nitrogen

  4. Influence of residue and nitrogen fertilizer additions on carbon mineralization in soils with different texture and cropping histories.

    Science.gov (United States)

    Chen, Xianni; Wang, Xudong; Liebman, Matt; Cavigelli, Michel; Wander, Michelle

    2014-01-01

    To improve our ability to predict SOC mineralization response to residue and N additions in soils with different inherent and dynamic organic matter properties, a 330-day incubation was conducted using samples from two long-term experiments (clay loam Mollisols in Iowa [IAsoil] and silt loam Ultisols in Maryland [MDsoil]) comparing conventional grain systems (Conv) amended with inorganic fertilizers with 3 yr (Med) and longer (Long), more diverse cropping systems amended with manure. A double exponential model was used to estimate the size (Ca, Cs) and decay rates (ka, ks) of active and slow C pools which we compared with total particulate organic matter (POM) and occluded-POM (OPOM). The high-SOC IAsoil containing highly active smectite clays maintained smaller labile pools and higher decay rates than the low-SOC MDsoil containing semi-active kaolinitic clays. Net SOC loss was greater (2.6 g kg(-1); 8.6%) from the IAsoil than the MDsoil (0.9 g kg(-1), 6.3%); fractions and coefficients suggest losses were principally from IAsoil's resistant pool. Cropping history did not alter SOC pool size or decay rates in IAsoil where rotation-based differences in OPOM-C were small. In MDsoil, use of diversified rotations and manure increased ka by 32% and ks by 46% compared to Conv; differences mirrored in POM- and OPOM-C contents. Residue addition prompted greater increases in Ca (340% vs 230%) and Cs (38% vs 21%) and decreases in ka (58% vs 9%) in IAsoil than MDsoil. Reduced losses of SOC from residue-amended MDsoil were associated with increased OPOM-C. Nitrogen addition dampened CO2-C release. Clay type and C saturation dominated the IAsoil's response to external inputs and made labile and stable fractions more vulnerable to decay. Trends in OPOM suggest aggregate protection influences C turnover in the low active MDsoil. Clay charge and OPOM-C contents were better predictors of soil C dynamics than clay or POM-C contents. PMID:25078458

  5. Influence of residue and nitrogen fertilizer additions on carbon mineralization in soils with different texture and cropping histories.

    Directory of Open Access Journals (Sweden)

    Xianni Chen

    Full Text Available To improve our ability to predict SOC mineralization response to residue and N additions in soils with different inherent and dynamic organic matter properties, a 330-day incubation was conducted using samples from two long-term experiments (clay loam Mollisols in Iowa [IAsoil] and silt loam Ultisols in Maryland [MDsoil] comparing conventional grain systems (Conv amended with inorganic fertilizers with 3 yr (Med and longer (Long, more diverse cropping systems amended with manure. A double exponential model was used to estimate the size (Ca, Cs and decay rates (ka, ks of active and slow C pools which we compared with total particulate organic matter (POM and occluded-POM (OPOM. The high-SOC IAsoil containing highly active smectite clays maintained smaller labile pools and higher decay rates than the low-SOC MDsoil containing semi-active kaolinitic clays. Net SOC loss was greater (2.6 g kg(-1; 8.6% from the IAsoil than the MDsoil (0.9 g kg(-1, 6.3%; fractions and coefficients suggest losses were principally from IAsoil's resistant pool. Cropping history did not alter SOC pool size or decay rates in IAsoil where rotation-based differences in OPOM-C were small. In MDsoil, use of diversified rotations and manure increased ka by 32% and ks by 46% compared to Conv; differences mirrored in POM- and OPOM-C contents. Residue addition prompted greater increases in Ca (340% vs 230% and Cs (38% vs 21% and decreases in ka (58% vs 9% in IAsoil than MDsoil. Reduced losses of SOC from residue-amended MDsoil were associated with increased OPOM-C. Nitrogen addition dampened CO2-C release. Clay type and C saturation dominated the IAsoil's response to external inputs and made labile and stable fractions more vulnerable to decay. Trends in OPOM suggest aggregate protection influences C turnover in the low active MDsoil. Clay charge and OPOM-C contents were better predictors of soil C dynamics than clay or POM-C contents.

  6. Composting of waste paint sludge containing melamine resin as affected by nutrients and gypsum addition and microbial inoculation

    International Nuclear Information System (INIS)

    Melamine formaldehyde resins have hard and durable properties and are found in many products, including automobile paints. These resins contain high concentrations of nitrogen and, if properly composted, can yield valuable products. We evaluated the effects of starter compost, nutrients, gypsum and microbial inoculation on composting of paint sludge containing melamine resin. A bench-scale composting experiment was conducted at 55 °C for 91 days and then at 30 °C for an additional 56 days. After 91 days, the composts were inoculated with a mixed population of melamine-degrading microorganisms. Melamine resin degradation after the entire 147 days of composting varied between 73 and 95% for the treatments with inoculation of microorganisms compared to 55–74% for the treatments without inoculation. Degradation was also enhanced by nutrients and gypsum additions. Our results infer that large scale composting of melamine resins in paint sludge is possible. - Highlights: ► Melamine resin in waste paint sludges could be efficiently composted at bench scale. ► Melamine resin degradation after 147 days of composting was 73–95% complete. ► Nutrients, gypsum and melamine-degrading microorganisms increased composting rate. ► Melamine degradation products first increased and then decreased in the compost. ► Final compost was enriched in nitrogen and other essential plant nutrients. - Melamine resin in waste paint sludges was efficiently composted at bench scale, with finished composts having low levels of heavy metals and enriched in plant nutrients.

  7. The Potentially Affected Fraction for Target Species: Additional data and calculations

    OpenAIRE

    Traas TP; Luttik R; Posthumus R; ECO; CSR

    1998-01-01

    In studying the possibilities for mapping toxic pressure of contaminants (expressed as Potentially Affected Fraction, PAF) on such target species as butterflies, dragonflies, amphibians, reptiles and plants, the toxicity data available for butterflies, damselflies, dragonflies and reptiles were found to be insufficient. Low PAF values (less than 1%) for copper, zinc and cadmium were found for amphibians at median surface water concentrations. PAF calculations for higher plants indicate a high...

  8. Foliar Potassium Fertilizer Additives Affect Soybean Response and Weed Control with Glyphosate

    Directory of Open Access Journals (Sweden)

    Kelly A. Nelson

    2012-01-01

    Full Text Available Research in 2004 and 2005 determined the effects of foliar-applied K-fertilizer sources (0-0-62-0 (%N-%P2O5-%K2O-%S, 0-0-25-17, 3-18-18-0, and 5-0-20-13 and additive rates (2.2, 8.8, and 17.6 kg K ha−1 on glyphosate-resistant soybean response and weed control. Field experiments were conducted at Novelty and Portageville with high soil test K and weed populations and at Malden with low soil test K and weed populations. At Novelty, grain yield increased with fertilizer additives at 8.8 kg K ha−1 in a high-yield, weed-free environment in 2004, but fertilizer additives reduced yield up to 470 kg ha−1 in a low-yield year (2005 depending on the K source and rate. At Portageville, K-fertilizer additives increased grain yield from 700 to 1160 kg ha−1 compared to diammonium sulfate, depending on the K source and rate. At Malden, there was no yield response to K sources. Differences in leaf tissue K (P=0.03, S (P=0.03, B (P=0.0001, and Cu (P=0.008 concentrations among treatments were detected 14 d after treatment at Novelty and Malden. Tank mixtures of K-fertilizer additives with glyphosate may provide an option for foliar K applications.

  9. Model uncertainties affecting satellite-based inverse modeling of nitrogen oxides emissions and implications for surface ozone simulation

    Directory of Open Access Journals (Sweden)

    J.-T. Lin

    2012-06-01

    Full Text Available Errors in chemical transport models (CTMs interpreting the relation between space-retrieved tropospheric column densities of nitrogen dioxide (NO2 and emissions of nitrogen oxides (NOx have important consequences on the inverse modeling. They are however difficult to quantify due to lack of adequate in situ measurements, particularly over China and other developing countries. This study proposes an alternate approach for model evaluation over East China, by analyzing the sensitivity of modeled NO2 columns to errors in meteorological and chemical parameters/processes important to the nitrogen abundance. As a demonstration, it evaluates the nested version of GEOS-Chem driven by the GEOS-5 meteorology and the INTEX-B anthropogenic emissions and used with retrievals from the Ozone Monitoring Instrument (OMI to constrain emissions of NOx. The CTM has been used extensively for such applications. Errors are examined for a comprehensive set of meteorological and chemical parameters using measurements and/or uncertainty analysis based on current knowledge. Results are exploited then for sensitivity simulations perturbing the respective parameters, as the basis of the following post-model linearized and localized first-order modification. It is found that the model meteorology likely contains errors of various magnitudes in cloud optical depth, air temperature, water vapor, boundary layer height and many other parameters. Model errors also exist in gaseous and heterogeneous reactions, aerosol optical properties and emissions of non-nitrogen species affecting the nitrogen chemistry. Modifications accounting for quantified errors in 10 selected parameters increase the NO2 columns in most areas with an average positive impact of 22% in July and 10% in January. This suggests a possible systematic model bias such that the top-down emissions will be overestimated by the same magnitudes if the model is used

  10. Response of oxidative enzyme activities to nitrogen deposition affects soil concentrations of dissolved organic carbon

    Science.gov (United States)

    Waldrop, M.P.; Zak, D.R.

    2006-01-01

    Recent evidence suggests that atmospheric nitrate (NO3- ) deposition can alter soil carbon (C) storage by directly affecting the activity of lignin-degrading soil fungi. In a laboratory experiment, we studied the direct influence of increasing soil NO 3- concentration on microbial C cycling in three different ecosystems: black oak-white oak (BOWO), sugar maple-red oak (SMRO), and sugar maple-basswood (SMBW). These ecosystems span a broad range of litter biochemistry and recalcitrance; the BOWO ecosystem contains the highest litter lignin content, SMRO had intermediate lignin content, and SMBW leaf litter has the lowest lignin content. We hypothesized that increasing soil solution NO 3- would reduce lignolytic activity in the BOWO ecosystem, due to a high abundance of white-rot fungi and lignin-rich leaf litter. Due to the low lignin content of litter in the SMBW, we further reasoned that the NO3- repression of lignolytic activity would be less dramatic due to a lower relative abundance of white-rot basidiomycetes; the response in the SMRO ecosystem should be intermediate. We increased soil solution NO3- concentrations in a 73-day laboratory incubation and measured microbial respiration and soil solution dissolved organic carbon (DOC) and phenolics concentrations. At the end of the incubation, we measured the activity of ??-glucosidase, N-acetyl-glucosaminidase, phenol oxidase, and peroxidase, which are extracellular enzymes involved with cellulose and lignin degradation. We quantified the fungal biomass, and we also used fungal ribosomal intergenic spacer analysis (RISA) to gain insight into fungal community composition. In the BOWO ecosystem, increasing NO 3- significantly decreased oxidative enzyme activities (-30% to -54%) and increased DOC (+32% upper limit) and phenolic (+77% upper limit) concentrations. In the SMRO ecosystem, we observed a significant decrease in phenol oxidase activity (-73% lower limit) and an increase in soluble phenolic concentrations

  11. Effects of experimental warming and nitrogen addition on soil respiration and CH4 fluxes from crop rotations of winter wheat–soybean/fallow

    DEFF Research Database (Denmark)

    Liu, L; Hu, C; Yang, P;

    2015-01-01

    experiment was conducted at Luancheng research station in the North China Plain from 2008 to 2013. Two levels of temperature (T: increase on average 1.5 °C at 5 cm soil depth by infrared heaters, C: ambient temperature) were combined with two levels of nitrogen (N) treatments (N1: with 315 kg N ha−1 y−1, N0......: no nitrogen input) in the farmland. Soil was found to be a sink for CH4 with no marked seasonal variations. In the wheat-growing season, warming and N input both decreased cumulative CH4 uptake, probably because warming-induced soil drying in N1 treatment reduced (or limited) methanotroph activity by...... affecting soil NH4 concentration. Across years, CH4 emissions were negatively correlated with soil temperature in N1 treatment. Soil respiration showed clear seasonal fluctuations, with the largest emissions during summer and smallest in winter. Warming and nitrogen fertilization had no significant effects...

  12. Soil aggregate stability as affected by clay mineralogy and polyacrylamide addition

    Science.gov (United States)

    The addition of polyacrylamide (PAM) to soil leads to stabilization of existing aggregates and improved bonding between, and aggregation of adjacent soil particles However, the dependence of PAM efficacy as an aggregate stabilizing agent on soil-clay mineralogy has not been studied. Sixteen soil sam...

  13. Activated carbon addition affects substrate pH and germination of six plant species

    NARCIS (Netherlands)

    Kabouw, P.; Nab, M.; Dam, van M.

    2010-01-01

    Activated carbon (AC) is widely used in ecological studies for neutralizing allelopathic compounds. However, it has been suggested that AC has direct effects on plants because it alters substrate parameters such as nutrient availability and pH. These side-effects of AC addition may interfere with al

  14. Comparison of Temperature and Additives Affecting the Stability of the Probiotic Weissella cibaria.

    Science.gov (United States)

    Kang, Mi-Sun; Kim, Youn-Shin; Lee, Hyun-Chul; Lim, Hoi-Soon; Oh, Jong-Suk

    2012-12-01

    Daily use of probiotic chewing gum might have a beneficial effect on oral health, and it is important that the viability of the probiotics be maintained in this food product. In this study, we examined the stability of probiotic chewing gum containing Weissella cibaria. We evaluated the effects of various factors, including temperature and additives, on the survival of freeze-dried probiotic W. cibaria powder. No changes in viability were detected during storage at 4℃ for 5 months, whereas the viability of bacteria stored at 20℃ decreased. The stability of probiotic chewing gum decreased steadily during storage at 20℃ for 4 weeks. The viability of the freeze-dried W. cibaria mixed with various additives, such as xylitol, sorbitol, menthol, sugar ester, magnesium stearate, and vitamin C, was determined over a 4-week storage period at 20℃. Most of the freeze-dried bacteria except for those mixed with menthol and vitamin C were generally stable during a 3-week storage period. Overall, our study showed that W. cibaria was more stable at 4℃ than that at 20℃. In addition, menthol and vitamin C had a detrimental effect on the storage stability of W. cibaria. This is the first study to examine the effects of various chewing gum additives on the stability of W. cibaria. Further studies will be needed to improve the stability of probiotic bacteria for developing a novel probiotic W. cibaria gum. PMID:23323221

  15. Volatilization of ammonia from manure as affected by manure additives, temperature and mixing.

    NARCIS (Netherlands)

    Stelt, van der B.; Temminghoff, E.J.M.; Vliet, van P.C.J.; Riemsdijk, van W.H.

    2007-01-01

    Ammonia (NH3) volatilization decreases the N-nutrient value of livestock manure slurries and can lead to soil acidification and eutrophication problems. In this study the effect of three manure additives (Euro Mest-mix® (Mx), Effective Micro-organisms® (EM), and Agri-mest® (Am)) on NH3 volatilizatio

  16. Levels of nitrogen and iodosulfuron + mesosulfuron affecting the wheat competitive ability against weeds

    Directory of Open Access Journals (Sweden)

    Mahdi Zare

    2014-08-01

    Full Text Available The trial was a split plot experiment based on randomized complete block design (RCBD with four replications in Abadeh, Fars, Iran, during 2010-2011 growing seasons. The treatments were consisted of three levels of nitrogen (200, 300, and 400 kg ha-1 and four herbicide application levels (53, 68, 83, and 97 g ha-1. Interaction effects of N fertilizer×herbicide levels on number spike per m2, number of kernels spike-1, 1000-seed weight, harvest index, seed yield, number of wild oat, number of common mallow and common mallow dry matter weight were significant. The maximum seed yield was related to 300 kg ha-1 N fertilizer with 97 g ha-1 herbicide treatment (3,526 kg ha-1 and the minimum seed yield was belonged to 200 kg ha-1 N fertilizer with 53 g ha-1 herbicide treatment (2,242 kg ha-1. Number of spikes m-2 was the most important trait contributing to the grain yield in wheat. In conclusion, weed control was essential for efficient use of N fertilizer by the crop. Therefore, integration of N fertilization and herbicide is recommended for the region to increase wheat grain yield.

  17. Nitrogen and Carbon Cycling in a Grassland Community Ecosystem as Affected by Elevated Atmospheric CO2

    Directory of Open Access Journals (Sweden)

    H. A. Torbert

    2012-01-01

    Full Text Available Increasing global atmospheric carbon dioxide (CO2 concentration has led to concerns regarding its potential effects on terrestrial ecosystems and the long-term storage of carbon (C and nitrogen (N in soil. This study examined responses to elevated CO2 in a grass ecosystem invaded with a leguminous shrub Acacia farnesiana (L. Willd (Huisache. Seedlings of Acacia along with grass species were grown for 13 months at CO2 concentrations of 385 (ambient, 690, and 980 μmol mol−1. Elevated CO2 increased both C and N inputs from plant growth which would result in higher soil C from litter fall, root turnover, and excretions. Results from the incubation indicated an initial (20 days decrease in N mineralization which resulted in no change in C mineralization. However, after 40 and 60 days, an increase in both C and N mineralization was observed. These increases would indicate that increases in soil C storage may not occur in grass ecosystems that are invaded with Acacia over the long term.

  18. Does the addition of proteases affect the biogas yield from organic material in anaerobic digestion?

    Science.gov (United States)

    Müller, Liane; Kretzschmar, Jörg; Pröter, Jürgen; Liebetrau, Jan; Nelles, Michael; Scholwin, Frank

    2016-03-01

    The aim of this study was to investigate the biochemical disintegration effect of hydrolytic enzymes in lab scale experiments. Influences of enzyme addition on the biogas yield as well as effects on the process stability were examined. The addition of proteases occurred with low and high dosages in batch and semi-continuous biogas tests. The feed mixture consisted of maize silage, chicken dung and cow manure. Only very high concentrated enzymes caused an increase in biogas production in batch experiments. In semi-continuous biogas tests no positive long-term effects (100 days) were observed. Higher enzyme-dosage led to a reduced biogas-yield (13% and 36% lower than the reference). Phenylacetate and -propionate increased (up to 372 mgl(-1)) before the other volatile fatty acids did. Volatile organic acids rose up to 6.8 gl(-1). The anaerobic digestion process was inhibited. PMID:26741852

  19. Comparison of Temperature and Additives Affecting the Stability of the Probiotic Weissella cibaria

    OpenAIRE

    Kang, Mi-Sun; Kim, Youn-Shin; Lee, Hyun-chul; Lim, Hoi-Soon; Oh, Jong-Suk

    2012-01-01

    Daily use of probiotic chewing gum might have a beneficial effect on oral health, and it is important that the viability of the probiotics be maintained in this food product. In this study, we examined the stability of probiotic chewing gum containing Weissella cibaria. We evaluated the effects of various factors, including temperature and additives, on the survival of freeze-dried probiotic W. cibaria powder. No changes in viability were detected during storage at 4℃ for 5 months, whereas th...

  20. Different procedures of diphenyleneiodonium chloride addition affect neutrophil extracellular trap formation.

    Science.gov (United States)

    Ostafin, Magdalena; Pruchniak, Michal Przemyslaw; Ciepiela, Olga; Reznick, Abraham Zeev; Demkow, Urszula

    2016-09-15

    A unique strategy, in which invading microorganisms are being caught in web-like structures composed mainly of DNA, involves a recently described phenomenon called NETosis. This process seems to be related to the production of reactive oxygen species (ROS). In our study, the influence of diphenyleneiodonium chloride (DPI), which diminishes ROS production, was assessed in the context of neutrophil extracellular trap (NET) release. According to protocol, two distinguished procedures were compared, the first one involving DPI elimination from sample before cell activation and the second one proceeding without the step of inhibitor washout. The kinetics of DNA release was monitored by fluorometric assay, and NET formation was observed by fluorescent microscopy. The addition of DPI to the sample led to a reduction of extracellular DNA release. The strongest inhibition was noticed after treatment with 10 μM DPI, which was removed from medium before stimulation with phorbol-12-myristate-13-acetate (PMA). Our findings confirmed that DPI is able to block NET creation. However, the addition of DPI together with PMA or the addition of inhibitor initially and then washing it out before stimulation resulted in different levels of NET formation. Finally, DPI that remained in the system induced specific morphological changes in the neutrophils' nuclei that was not observed in the DPI washed out from sample. PMID:27179553

  1. Wheat (Triticum aestivum) seedlings secrete proteases from the roots and, after protein addition, grow well on medium without inorganic nitrogen.

    Science.gov (United States)

    Adamczyk, B; Godlewski, M; Zimny, J; Zimny, A

    2008-11-01

    This paper reports on the role of proteases secreted by roots in nitrogen capture by plants. The study was conducted on aseptically cultivated wheat seedlings (Triticum aestivum cv. Tacher) obtained from embryos isolated from grains. Seedlings were cultivated for 21 days on deionised water, Murashige Skoog medium (MS), MS without inorganic nitrogen (IN), and MS without IN, in which IN was replaced by casein (0.01%, 0.1% or 1%). Comparison of seedlings grown on these media showed that casein entirely compensated for the lack of inorganic nitrogen in the medium. Shoots and roots of seedlings cultivated on MS medium with this protein had higher fresh weight than those cultivated on MS medium without casein. The increase in fresh weight of seedlings was correlated with casein concentration and proteolytic activity in the medium. In conclusion, wheat that uses proteases secreted by the roots can directly utilise proteins in the medium as a source of nitrogen without prior digestion by microbial proteases and without protein mineralisation. These results suggest the important role of organic nitrogen fertilisers in increasing wheat yield. PMID:18950429

  2. Effects of wood-ash addition on nitrogen turnover in a highly nitrogen loaded spruce site. Final project report; Effekter av askaaterfoering paa kvaeveomsaettningen i ett kvaeverikt granbestaand i Halland. Slutrapport foer projektet

    Energy Technology Data Exchange (ETDEWEB)

    Nohrstedt, H.Oe.; Hoegbom, Lars; Nordlund, Sten [Forestry Research Inst. of Sweden, Uppsala (Sweden)

    2000-04-01

    During two consecutive years, it was studied how a fertilization with 4.2 tonnes pelleted bark ash per ha, made six-seven years earlier, affected soil chemistry, nitrogen turnover and soil-water chemistry on a Norway spruce site in SW Sweden. The actual site has a very acidic soil. At the same time, the supply of inorganic N is rich. Measures against soil acidification, e. g. addition of ash or lime, may significantly influence the turnover of N with a subsequent risk for increased leaching. Thus, there is a potential conflict between two urgent environmental goals, i. e. to decrease acidification and to decrease the N load on aquatic ecosystems. In the humus layer and the upper 5 cm of the mineral soil, pH(H{sub 2}O) had increased with at the most 0.2 units because of the ash addition. The easily extractable amounts of Mg, P and nitrate were slightly increased. The potential nitrification in the humus layer was generally higher in the ash treatment, but the difference. was not statistically significant. The soil water at 50 cm depth was 0.1-0.2 pH-units more acidic where ash had been applied. Simultaneously, there were tendencies for higher concentrations of nitrate, Al and K. This is the first time in Sweden that ash fertilization of a closed forest has given clear indications of an increased N leaching. As expected, the ash fertilization decreased the acidity of the top soil. On the contrary, the runoff became more acidic and more rich in Al. Thus, the ash fertilization has counteracted one of its primary goals, i. e. to produce a runoff less toxic to aquatic life. The acidification of the runoff may partially be because of acid production during nitrification.

  3. Mineralization and carbon turnover in subarctic heath soil as affected by warming and additional litter

    DEFF Research Database (Denmark)

    Rinnan, Riikka; Michelsen, Anders; Baath, Erland;

    2007-01-01

    carbon turnover (measured as changes in the pools during a growing-season-long field incubation of soil cores in situ). The mainly N limited bacterial communities had shifted slightly towards limitation by C and P in response to seven growing seasons of warming. This and the significantly increased...... bacterial growth rate under warming may partly explain the observed higher C loss from the warmed soil. This is furthermore consistent with the less dramatic increase in the contents of dissolved organic carbon (DOC) and dissolved organic N (DON) in the warmed soil than in the soil from ambient temperature...... during the field incubation. The added litter did not affect the carbon content, but it was a source of nutrients to the soil, and it also tended to increase bacterial growth rate and net mineralization of P. The inorganic N pool decreased during the field incubation of soil cores, especially in the...

  4. Response of AM fungi spore population to elevated temperature and nitrogen addition and their influence on the plant community composition and productivity

    OpenAIRE

    Tao Zhang; Xue Yang; Rui Guo; Jixun Guo

    2016-01-01

    To examine the influence of elevated temperature and nitrogen (N) addition on species composition and development of arbuscular mycorrhizal fungi (AMF) and the effect of AMF on plant community structure and aboveground productivity, we conducted a 5-year field experiment in a temperate meadow in northeast China and a subsequent greenhouse experiment. In the field experiment, N addition reduced spore population diversity and richness of AMF and suppressed the spore density and the hyphal lengt...

  5. Effects of nitrogen addition and precipitation change on soil methane and carbon dioxide fluxes%施氮和降水格局改变对土壤CH4和CO2通量的影响

    Institute of Scientific and Technical Information of China (English)

    李伟; 白娥; 李善龙; 孙建飞; 彭勃; 姜萍

    2013-01-01

    氮沉降增加和降水格局改变是全球变化的两项重要内容,但是同时考虑上述两因素对温室气体CH4和CO2通量影响的原位双因子模拟研究还相当有限.本研究以长白山温带阔叶红松林土壤为研究对象,采用静态箱法研究了外施氮源(50 kg N·hm-2·a-1)和增减30%降水对土壤CH4和CO2通量的影响.结果表明:施氮能抑制土壤CH4吸收,有时甚至能将土壤对CH4的吸收转为释放,但这种抑制效应只能维持5d左右,且能在一定程度上改变CH4通量和环境因子(温度、土壤pH、粘粒含量)的相关关系.降水改变未能显著影响土壤CH4通量.对CO2通量而言,施氮能降低土壤CO2排放,长白山阔叶红松林连续施氮第4年的平均抑制效应为27.4%.长期连续施氮的平均抑制效应随施氮时间延长而逐渐增大,一定年限后达到最大值.单次施氮的抑制效应随时间延长逐渐减弱,并在1个月的施氮周期末期基本消失.施氮的抑制效应和土壤充水孔隙度(WFPS)呈显著负相关关系,且升温能增强施氮对CO2释放的抑制效应并延长抑制时间.施氮、降水有可能改变土壤呼吸的温度敏感性.本研究表明,长白山森林土壤氮素尚未达到一定阈值,未来氮沉降增加将抑制CO2的释放和CH4的吸收,因此总体来看施氮抑制土壤碳排放.%Increased nitrogen deposition and changed precipitation pattern are the two important factors of global change,while the in situ experiments studying how the two factors affect greenhouse gases CO2 and CH4 fluxes are still limited.Taking the temperate broad-leaved Korean pine (Pinus koraiensis) forest in Changbai Mountains of Northeast China as the object,and by using static chambers,this paper studied the effects of nitrogen addition (50 kg N · hm-2 · a-1) and changed precipitation regime (30% increase and decrease of precipitation) on the soil CO2 and CH4 fluxes.Nitrogen addition inhibited the soil CH4 consumption

  6. Particulate Organic Matter Affects Soil Nitrogen Mineralization under Two Crop Rotation Systems.

    Directory of Open Access Journals (Sweden)

    Rongyan Bu

    Full Text Available Changes in the quantity and/or quality of soil labile organic matter between and after different types of cultivation system could play a dominant role in soil nitrogen (N mineralization. The quantity and quality of particulate organic matter (POM and potentially mineralizable-N (PMN contents were measured in soils from 16 paired rice-rapeseed (RR/cotton-rapeseed (CR rotations sites in Hubei province, central China. Then four paired soils encompassing low (10th percentile, intermediate (25th and 75th percentiles, and high (90th percentile levels of soil PMN were selected to further study the effects of POM on soil N mineralization by quantifying the net N mineralization in original soils and soils from which POM was removed. Both soil POM carbon (POM-C and N (POM-N contents were 45.8% and 55.8% higher under the RR rotation compared to the CR rotation, respectively. The PMN contents were highly correlated with the POM contents. The PMN and microbial biomass N (MBN contents concurrently and significantly decreased when POM was removed. The reduction rate of PMN was positively correlated with changes in MBN after the removal of POM. The reduction rates of PMN and MBN after POM removal are lower under RR rotations (38.0% and 16.3%, respectively than CR rotations (45.6% and 19.5%, respectively. Furthermore, infrared spectroscopy indicated that compounds with low-bioavailability accumulated (e.g., aromatic recalcitrant materials in the soil POM fraction under the RR rotation but not under the CR rotation. The results of the present study demonstrated that POM plays a vital role in soil N mineralization under different rotation systems. The discrepancy between POM content and composition resulting from different crop rotation systems caused differences in N mineralization in soils.

  7. Calcium Addition Affects Germination and Early Seedling Growth of Sweet Sorghum under Saline Conditions

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    [Objective] This study aimed to determine the interactive effects of supple- mental Ca amendment and salinity on germination of sweet sorghum seeds in saline solution culture medium, and investigate the effects of different combinations of Na/Ca ratio in saline soils on the early growth of sweet sorghum plants. [Method] A germi- nation test and a greenhouse pot experiment were conducted to assess the interac- tive effects of calcium addition to culture medium on the germination and seedling growth of sweet sorghum (Sorghum saccharatum Moench) in saline soils with a range of NaYCa ratios. In the germination test, seeds were treated with different combinations of five calcium levels [0, 5, 10, 15, and 20 mmol/L Ca(NO3)2] and five salinity levels (0, 50, 100, 150, and 200 mmol/L NaCI). In the greenhouse experi- ment, seeds were sown in potting soils containing 3 salinity levels (2.3, 4.7 and 7.0 dS/m) and three Na:Ca ratios (10:0, 10:1, and 5:1). [Result] In the germination test, Ca addition at 5 mmol/L promoted germination by 5.5%, 9.9%, and 17.0% at the 3.4, 6.7 and 10.1 dS/m salinity levels. The higher Ca level (10 mmol/L) also in- creased germination by 9.1% and 7.8% at the 3.4 and 6.7 dS/m salinity levels. Then even higher Ca addition at 15 and 20 mmol/L appeared to promote germina- tion when culture media had high salinity (10.1 and 13.4 dS/m). In the greenhouse pot experiment, saline soil amended with supplemental Ca at the 2.3 and 4.7 dS/m salinity levels significantly promoted early seedling growth, with an increase of 6.8% to 28.2% in plant height and 14.3% to 67.9% in whole plant weight. From 28 to 42 d after seeding, the relative growth of seedling was increased by Ca addition, with a reduction of 49.5% to 66.0% in plant height and 4.8% to 61.9% in whole plant weight. From 42 to 56 d after seeding, however, the relative growth of seedling was significantly inhibited by Ca amendment. [Conclusion] Results of this study indicate that appropriate supplemental

  8. The addition of organic carbon and nitrate affects reactive transport of heavy metals in sandy aquifers

    KAUST Repository

    Satyawali, Yamini

    2011-04-01

    Organic carbon introduction in the soil to initiate remedial measures, nitrate infiltration due to agricultural practices or sulphate intrusion owing to industrial usage can influence the redox conditions and pH, thus affecting the mobility of heavy metals in soil and groundwater. This study reports the fate of Zn and Cd in sandy aquifers under a variety of plausible in-situ redox conditions that were induced by introduction of carbon and various electron acceptors in column experiments. Up to 100% Zn and Cd removal (from the liquid phase) was observed in all the four columns, however the mechanisms were different. Metal removal in column K1 (containing sulphate), was attributed to biological sulphate reduction and subsequent metal precipitation (as sulphides). In the presence of both nitrate and sulphate (K2), the former dominated the process, precipitating the heavy metals as hydroxides and/or carbonates. In the presence of sulphate, nitrate and supplemental iron (Fe(OH)3) (K3), metal removal was also due to precipitation as hydroxides and/or carbonates. In abiotic column, K4, (with supplemental iron (Fe(OH)3), but no nitrate), cation exchange with soil led to metal removal. The results obtained were modeled using the reactive transport model PHREEQC-2 to elucidate governing processes and to evaluate scenarios of organic carbon, sulphate and nitrate inputs. © 2010 Elsevier B.V.

  9. Shear and Rapeseed Oil Addition Affect the Crystal Polymorphic Behavior of Milk Fat

    DEFF Research Database (Denmark)

    Kaufmann, Niels; Kirkensgaard, Jacob Judas Kain; Andersen, Ulf; Wiking, Lars

    2013-01-01

    crystallized at 5 C and shear of 0, 74 or 444 s-1 was applied during early crystallization, in the NMR tube. High shear rates decreased the amount of a polymorph formed and accelerated the polymorphic transition; however, shear did not affect the final solid fat content (SFC). The a to b0 transition occurred......The effect of shear on the crystallization kinetics of anhydrous milk fat (AMF) and blends with 20 and 30 % w/w added rapeseed oil (RO) was studied. Pulse 1H NMR was used to follow the a to b0 polymorphic transition. The NMR method was confirmed and supported by SAXS/WAXS experiments. Samples were...... faster in the presence of RO allowing more room for the conformational changes to occur. Final SFC decreased with increasing RO content. Shear applied in 20 and 30 % blends caused the destruction of b0-related 3L structure leaving only 2L packing. In AMF and statically crystallized samples, both 3L and 2...

  10. Importance of within-lake processes in affecting the dynamics of dissolved organic carbon and dissolved organic and inorganic nitrogen in an Adirondack forested lake/watershed

    OpenAIRE

    Kang, P.-G.; M. J. Mitchell; McHale, P J; Driscoll, C T; M. R. McHale; Inamdar, S.; Park, J.-H.

    2015-01-01

    Lakes nested in forested watersheds play important roles in mediating the concentrations and fluxes of dissolved organic matter. We compared long-term patterns of concentrations and fluxes of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and dissolved inorganic nitrogen (DIN) in the Arbutus Lake Watershed to evaluate how a lake nested in a forested watershed affects the dynamics of DOC and DON in the Adirondack Mountains of New York State...

  11. Effect of nitrogen addition and drought on above-ground biomass of expanding tall grasses Calamagrostis epigejos and Arrhenatherum elatius

    Czech Academy of Sciences Publication Activity Database

    Fiala, Karel; Tůma, Ivan; Holub, Petr

    2011-01-01

    Roč. 66, č. 2 (2011), s. 275-281. ISSN 0006-3088 R&D Projects: GA ČR(CZ) GA526/06/0556 Institutional research plan: CEZ:AV0Z60050516 Keywords : nitrogen * drought * above-ground biomass Subject RIV: EF - Botanics Impact factor: 0.557, year: 2011

  12. Electron beam irradiation and addition of poly(vinyl alcohol) affect gelatin based-films properties

    International Nuclear Information System (INIS)

    Gelatin is a mixture of high molecular weight polypeptides, product of denaturation, and partial structural degradation of collagen, and one of the first materials employed as biomaterials. Aqueous solutions of gelatin (10%), glycerin as plasticizer and poly(vinyl alcohol) (PVA) up to 10% were prepared in a water bath at 70 deg C under constant stirring. Films were irradiated with 10 and 20 kGy using an electron beam accelerator, dose rate of 22.4 kGy s-1, energy 1.407 MeV, at room temperature, in the presence of air. After irradiation, mechanical properties, color measurements, water absorption, moisture and film solubility were analyzed. The films showed an improvement in maximum force to rupture the film with increase of the irradiation dose. The higher the puncture force to rupture the lower the elongation at break. Colorimetric tests showed significant differences between samples, and also differences depending of the applied radiation dose, and analyzed color parameter. In water absorption tests a decrease of absorption percentage was found with the increase of the dose for PVA free and 5% PVA samples. The addition of PVA increased the water absorption for all applied doses. The modifications in gelatin colloids can be appointed to radiation-induced crosslinking. Also, the PVA concentration in the samples influenced the resultant material properties. (author)

  13. Picloram and napropamide sorption as affected by polymer addition and salt concentration.

    Science.gov (United States)

    Lu, Jianhang; Wu, Laosheng; Letey, John; Farmer, Walter J

    2002-01-01

    Polymer application to soil is a growing practice to improve soil physical properties and reduce soil erosion. Polymer addition can potentially influence herbicide and pesticide sorption in soil. The one-point distribution coefficient Kd values of two herbicides in the absence and presence of each of 10 polymers (7 polyacrylamides and 3 polysaccharides) were determined by the batch equilibrium method. The results showed that nonionic napropamide [2-(alpha-naphthoxy)-N,N-diethyl propionamide] sorption was essentially unaffected by the presence of any of the polymers. The influence of polymers on anionic picloram (4-amino-3,5,6-trichloropicolinic acid) sorption depends on the charge characteristics of polymers and salt concentrations in the solution. Electrostatic interaction and competition for sorption sites are two primary underlying mechanisms for the polymer influence. At low salt concentration, the increased picloram sorption in the presence of both cationic and anionic polymers was attributed to different electrostatic interactions and polymer partitioning between soil and solution phases. At high salt levels, the presence of polymers had either no influence or a slightly negative influence on the picloram sorption, which was attributed to competition for sorption sites. In field conditions, it is more likely that polymers have no or a slightly negative influence on herbicide sorption due to the presence of salts. PMID:12175041

  14. Electron beam irradiation and addition of poly(vinyl alcohol) affect gelatin based-films properties

    Energy Technology Data Exchange (ETDEWEB)

    Inamura, Patricia Y.; Mastro, Nelida L. del, E-mail: pinamura@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2015-07-01

    Gelatin is a mixture of high molecular weight polypeptides, product of denaturation, and partial structural degradation of collagen, and one of the first materials employed as biomaterials. Aqueous solutions of gelatin (10%), glycerin as plasticizer and poly(vinyl alcohol) (PVA) up to 10% were prepared in a water bath at 70 deg C under constant stirring. Films were irradiated with 10 and 20 kGy using an electron beam accelerator, dose rate of 22.4 kGy s{sup -1}, energy 1.407 MeV, at room temperature, in the presence of air. After irradiation, mechanical properties, color measurements, water absorption, moisture and film solubility were analyzed. The films showed an improvement in maximum force to rupture the film with increase of the irradiation dose. The higher the puncture force to rupture the lower the elongation at break. Colorimetric tests showed significant differences between samples, and also differences depending of the applied radiation dose, and analyzed color parameter. In water absorption tests a decrease of absorption percentage was found with the increase of the dose for PVA free and 5% PVA samples. The addition of PVA increased the water absorption for all applied doses. The modifications in gelatin colloids can be appointed to radiation-induced crosslinking. Also, the PVA concentration in the samples influenced the resultant material properties. (author)

  15. An addition of sourdough and whey proteins affects the nutritional quality of wholemeal wheat bread

    Directory of Open Access Journals (Sweden)

    Aneta Kopeć

    2014-03-01

    Full Text Available Background. Bread can be a good source of nutrients as well as non-nutrient compounds. This study was designed to assess the effect of adding of sourdough and whey proteins to wholemeal (WM bread produced by bake-off technology on chemical composition and bioavailability of proteins, calcium, phosphorus, magnesium and iron content in Wistar rats. Material and methods. Wholemeal breads were baked with using conventional or bake off technology. In breads chemical composition, selected minerals content, amino acid composition were measured. Five week-old Wistar rats (n = 30, male, were randomly divided into fi ve groups and fed with modifi ed AIN-93G diets containing experimental breads. In animal study the nutritional value of breads’ proteins and concentration of selected minerals in serum, liver and femoral bone, were measured. Results. The body weight gain, biological value (BV and net protein utilization (NPU were signifi cantly higher in rats fed with partially baked frozen wholemeal (PBF WM bread with sourdough and whey proteins. The level of magnesium was signifi cantly lower in serum of animals fed with the diet containing PBF WM bread with sourdough and whey proteins in comparison to rodents fed with conventional WM bread with sourdough. The content of iron was signifi cantly higher in liver of rats fed with PBF WM with sourdough bread in comparison to the groups fed with conventional WM and conventional WM with sourdough breads. Conclusions. Sourdough addition can be recommended in a production of whole wheat partially baked frozen bread but its use is further more benefi cial if it is fermented with whey proteins.

  16. Effects of additional fermented food wastes on nitrogen removal enhancement and sludge characteristics in a sequential batch reactor for wastewater treatment.

    Science.gov (United States)

    Zhang, Yongmei; Wang, Xiaochang C; Cheng, Zhe; Li, Yuyou; Tang, Jialing

    2016-07-01

    In order to enhance nitrogen removal from domestic wastewater with a carbon/nitrogen (C/N) ratio as low as 2.2:1, external carbon source was prepared by short-term fermentation of food wastes and its effect was evaluated by experiments using sequencing batch reactors (SBRs). The addition of fermented food wastes, with carbohydrate (42.8 %) and organic acids (24.6 %) as the main organic carbon components, could enhance the total nitrogen (TN) removal by about 25 % in contrast to the 20 % brought about by the addition of sodium acetate when the C/N ratio was equally adjusted to 6.6:1. The fermented food waste addition resulted in more efficient denitrification in the first anoxic stage of the SBR operation cycle than sodium acetate. In order to characterize the metabolic potential of microorganisms by utilizing different carbon sources, Biolog-ECO tests were conducted with activated sludge samples from the SBRs. As a result, in comparison with sodium acetate, the sludge sample by fermented food waste addition showed a greater average well color development (AWCD590), better utilization level of common carbon sources, and higher microbial diversity indexes. As a multi-organic mixture, fermented food wastes seem to be superior over mono-organic chemicals as an external carbon source. PMID:26988362

  17. Salinity and Salicylic Acid Interactions in Affecting Nitrogen Assimilation, Enzyme Activity, Ions Content and Translocation Rate of Maize Plants

    International Nuclear Information System (INIS)

    This study was carried out to establish the relationship between nitrogen metabolism, enzyme activity, ions concentration as well as the translocation rate (TR) of carbohydrates and salicylic acid (SA) in salt-stressed maize (Zea mays L). Salicylic acid plus salinity treatment highly significantly increased: nucleic acids (DNA and RNA), protein content, phosphoenolpyruvate carboxylase (PEPCase) and nitrate reductase (NR) and inhibited nucleases (DNase and RNase) activities compared with Na CI-treated plants. In addition, the ionic levels of potassium (K), phosphorus (P), nitrate (NO3) and the translocation rate of the labelled photo assimilates have also been stimulated while sodium (Na) ions content was decreased. It is concluded that, salinazid maize plants might show an enhancement in their growth pattern upon salicylic acid application

  18. Improving high temperature creep resistance of reduced activation steels by addition of nitrogen and intermediate heat treatment

    International Nuclear Information System (INIS)

    In the present study, we report an enhanced high-temperature creep resistance in reduced activation ferrite/martensite (RAFM) steels, by introducing nitrogen (0.035 wt%, M3 steel) and employing a novel intermediate heat treatment I–Q–T (intermediate treatment, quenching and tempering). In comparison with all the control groups, the uniaxial tests of the I–Q–T treated M3 steel showed significant increase in rupture time and decrease in elongation. The microstructures of the samples were further characterized to elucidate the origin of the enhanced creep resistance. It is found that, by introducing nitrogen, the primary TaC particles were refined; by employing the I–Q–T heat treatment, the dispersed fine secondary MX precipitates, as well as the lath subgrains containing high-density dislocations, were increased: all are responsible for the improved creep resistance

  19. NH4+ enrichment and UV radiation interact to affect the photosynthesis and nitrogen uptake of Gracilaria lemaneiformis (Rhodophyta)

    International Nuclear Information System (INIS)

    Highlights: ► Inhibition induced by UVR is alleviated with the enrichment of ammonia. ► Phycoerythrin plays a key protective role against UVR at higher level of ammonia. ► Effect of UVR on the uptakes of nitrate and ammonia is different. - Abstract: Solar ultraviolet radiation (UVR, 280–400 nm) is known to inhibit the photosynthesis of macroalgae, whereas nitrogen availability may alter the sensitivity of the algae to UVR. Here, we show that UV-B (280–315 nm) significantly reduced the net photosynthetic rate of Gracilaria lemaneiformis. This inhibition was alleviated by enrichment with ammonia, which also caused a decrease in dark respiration. The presence of both UV-A (315–400 nm) and UV-B stimulated the accumulation of UV-absorbing compounds. However, this stimulation was not affected by enrichment with ammonia. The content of phycoerythrin (PE) was increased by the enrichment of ammonia only in the absence of UVR. Ammonia uptake and the activity of nitrate reductase were repressed by UVR. However, exposure to UVR had an insignificant effect on the rate of nitrate uptake. In conclusion, increased PE content associated with ammonia enrichment played a protective role against UVR in this alga, and UVR differentially affected the uptake of nitrate and ammonia.

  20. Nitrous Oxide and Methane Emissions as Affected by Water, Soil and Nitrogen

    Institute of Scientific and Technical Information of China (English)

    XIONG Zheng-Qin; XING Guang-Xi; ZHU Zhao-Liang

    2007-01-01

    Specific management of water regimes,soil and N in China might play an important role in regulating N2O and CH4 emissions in rice fields.Nitrous oxide and methane emissions from alternate non-flooded/flooded paddies were monitored simultaneously during a 516-day incubation with lysimeter experiments.Two N sources (15N-(NH4)2SO4 and 15N-labeled milk vetch)were applied to two contrasting paddies:one derived from Xiashu loess(Loess)and one from Quaternary red clay(Clay).Both N2O and CH4 emissions were significantly higher in soil Clay than in soil Loess during the flooded period.For both soil,N2O emissions peaked at the transition periods shortly after the beginning of the flooded and non-flooded seasons.Soil type affected N2O emission patterns.In soil Clay,the emission peak during the transition period from non-flooded to flooded conditions was much higher than the peak during the transition period from flooded to non-flooded conditions.In soil Loess,the emission peak during the transition period from flooded to non-flooded conditions was obviously higher than the peak during the transition period from non-flooded to flooded conditions except for milk vetch treatment.Soil type also had a significant effect on CH4 emissions during the flooded season,over which the weighted average flux was 111 mg C m-2 h-1 and 2.2 mg C m-2 h-1 from Clay and Loess,respectively.Results indicated that it was the transition in the water regime that dominated N2O emissions while it was the soil type that dominated CH4 emissions during the flooded season.Anaerobic oxidation of methane possibly existed in soil Loess during the flooded season.

  1. Root-zone acidity affects relative uptake of nitrate and ammonium from mixed nitrogen sources

    Science.gov (United States)

    Vessey, J. K.; Henry, L. T.; Chaillou, S.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

    1990-01-01

    Soybean plants (Glycine max [L.] Merr. cv Ransom) were grown for 21 days on 4 sources of N (1.0 mM NO3-, 0.67 mM NO3- plus 0.33 mM NH4+, 0.33 mM NO3- plus 0.67 mM NH4+, and 1.0 mM NH4+) in hydroponic culture with the acidity of the nutrient solution controlled at pH 6.0, 5.5, 5.0, and 4.5. Dry matter and total N accumulation of the plants was not significantly affected by N-source at any of the pH levels except for decreases in these parameters in plants supplied solely with NH4+ at pH 4.5. Shoot-to-root ratios increased in plants which had an increased proportion [correction of proporiton] of NH4(+)-N in their nutrient solutions at all levels of root-zone pH. Uptake of NO3- and NH4+ was monitored daily by ion chromatography as depletion of these ions from the replenished hydroponic solutions. At all pH levels the proportion of either ion that was absorbed increased as the ratio of that ion increased in the nutrient solution. In plants which were supplied with sources of NO3- plus NH4+, NH4+ was absorbed at a ratio of 2:1 over NO3- at pH 6.0. As the pH of the root-zone declined, however, NH4+ uptake decreased and NO3- uptake increased. Thus, the NH4+ to NO3- uptake ratio declined with decreases in root-zone pH. The data indicate a negative effect of declining root-zone pH on NH4+ uptake and supports a hypothesis that the inhibition of growth of plants dependent on NH4(+)-N at low pH is due to a decline in NH4+ uptake and a consequential limitation of growth by N stress.

  2. Flavor and textural changes in radappertized chicken as affected by irradiation temperature, NaCl, and phosphate additions

    International Nuclear Information System (INIS)

    The effects of food-grade phosphates; sodium tripolyphosphate (TPP), tetrasodium pyrophosphate (PP), a mixture of tripolyphosphate and hexametaphosphate (HMP), and sodium chloride additions (0.05, 1.0, and 1.5 percent) in irradiated boneless chicken rolls were studied. Temperatures during irradiation processing were 00C, -300C, and -800C, and all samples received a 45 to 56 kJ/kg dose. Samples were evaluated for sensory characteristics and preference by technological or consumer type panels. Textural differences were determined using a Kramer Shear Press. Reflectance values at 640 nm were obtained using a reflectometer. The sensory characteristics and preference of the chicken rolls were significantly affected by temperature during irradiation. Samples irradiated at 00C were rated lower in preference and had higher intensities for off-odor and irradiation flavor. No significant differences were found between samples irradiated in a range of -300C to -800C. Shear press values increased and reflectance values decreased with the lowering of the irradiation temperatures. The addition of a small amount of salt with 0.5 percent tripolyphosphate significantly improved the preference ratings of irradiated chicken rolls. No differences in the sensory characteristics were found between roll samples with 0.5 percent additions of TPP, PP, or a TPP and HMP combination. Shear press values were significantly affected by the addition of NaCl and TPP in both irradiated and nonirradiated samples

  3. Nitrogen Use Efficiency as Affected by Phosphorus and Potassium in Long-Term Rice and Wheat Experiments

    Institute of Scientific and Technical Information of China (English)

    DUAN Ying-hua; SHI Xiao-jun; LI Shuang-lai; SUN Xi-fa; HE Xin-hua

    2014-01-01

    Improving nitrogen use efifciency (NUE) and decreasing N loss are critical to sustainable agriculture. The objective of this research was to investigate the effect of various fertilization regimes on yield, NUE, N agronomic efifciency (NAE) and N loss in long-term (16-or 24-yr) experiments carried out at three rice-wheat rotation sites (Chongqing, Suining and Wuchang) in subtropical China. Three treatments were examined: sole chemical N, N+phosphorus (NP), and NP+potassium (NPK) fertilizations. Grain yields at three sites were significantly increased by 9.3-81.6% (rice) and 54.5-93.8% (wheat) under NP compared with N alone, 1.7-9.8% (rice) and 0-17.6% (wheat) with NPK compared with NP. Compared to NP, NUE signiifcantly increased for wheat at Chongqing (9.3%) and Wuchang (11.8%), but not at Suining, China. No changes in NUE were observed in rice between NP and NPK at all three sites. The rice-wheat rotation’s NAE was 3.3 kg kg-1 higher under NPK than under NP at Chongqing, while NAE was similar for NP and NPK at Suining and Wuchang. We estimated that an uptake increase of 1.0 kg N ha-1 would increase 40 kg rice and 30 kg wheat ha-1. Nitrogen loss/input ratios were~60,~40 or~30%under N, NP or NPK at three sites, indicating signiifcant decrease of N loss by P or PK additions. We attribute part of the increase in NUE soil N accumulation which signiifcantly increased by 25-55 kg ha-1 yr-1 under NPK at three sites, whereas by 35 kg ha-1 yr-1 under NP at Chongqing only. This paper illustrates that apply P and K to wheat, and reduce K application to rice is an effective nutrient management strategy for both the NUE improvement and N losses reduction in China.

  4. Photosynthetic and growth response of sugar maple (Acer saccharum Marsh.) mature trees and seedlings to calcium, magnesium, and nitrogen additions in the Catskill Mountains, NY, USA

    Science.gov (United States)

    Momen, Bahram; Behling, Shawna J; Lawrence, Gregory B.; Sullivan, Joseph H

    2015-01-01

    Decline of sugar maple in North American forests has been attributed to changes in soil calcium (Ca) and nitrogen (N) by acidic precipitation. Although N is an essential and usually a limiting factor in forests, atmospheric N deposition may cause N-saturation leading to loss of soil Ca. Such changes can affect carbon gain and growth of sugar maple trees and seedlings. We applied a 22 factorial arrangement of N and dolomitic limestone containing Ca and Magnesium (Mg) to 12 forest plots in the Catskill Mountain region of NY, USA. To quantify the short-term effects, we measured photosynthetic-light responses of sugar maple mature trees and seedlings two or three times during two summers. We estimated maximum net photosynthesis (An-max) and its related light intensity (PAR at An-max), apparent quantum efficiency (Aqe), and light compensation point (LCP). To quantify the long-term effects, we measured basal area of living mature trees before and 4 and 8 years after treatment applications. Soil and foliar chemistry variables were also measured. Dolomitic limestone increased Ca, Mg, and pH in the soil Oe horizon. Mg was increased in the B horizon when comparing the plots receiving N with those receiving CaMg. In mature trees, foliar Ca and Mg concentrations were higher in the CaMg and N+CaMg plots than in the reference or N plots; foliar Ca concentration was higher in the N+CaMg plots compared with the CaMg plots, foliar Mg was higher in the CaMg plots than the N+CaMg plots; An-max was maximized due to N+CaMg treatment; Aqe decreased by N addition; and PAR at An-max increased by N or CaMg treatments alone, but the increase was maximized by their combination. No treatment effect was detected on basal areas of living mature trees four or eight years after treatment applications. In seedlings, An-max was increased by N+CaMg addition. The reference plots had an open herbaceous layer, but the plots receiving N had a dense monoculture of common woodfern in the

  5. Photosynthetic and Growth Response of Sugar Maple (Acer saccharum Marsh.) Mature Trees and Seedlings to Calcium, Magnesium, and Nitrogen Additions in the Catskill Mountains, NY, USA.

    Science.gov (United States)

    Momen, Bahram; Behling, Shawna J; Lawrence, Greg B; Sullivan, Joseph H

    2015-01-01

    Decline of sugar maple in North American forests has been attributed to changes in soil calcium (Ca) and nitrogen (N) by acidic precipitation. Although N is an essential and usually a limiting factor in forests, atmospheric N deposition may cause N-saturation leading to loss of soil Ca. Such changes can affect carbon gain and growth of sugar maple trees and seedlings. We applied a 22 factorial arrangement of N and dolomitic limestone containing Ca and Magnesium (Mg) to 12 forest plots in the Catskill Mountain region of NY, USA. To quantify the short-term effects, we measured photosynthetic-light responses of sugar maple mature trees and seedlings two or three times during two summers. We estimated maximum net photosynthesis (An-max) and its related light intensity (PAR at An-max), apparent quantum efficiency (Aqe), and light compensation point (LCP). To quantify the long-term effects, we measured basal area of living mature trees before and 4 and 8 years after treatment applications. Soil and foliar chemistry variables were also measured. Dolomitic limestone increased Ca, Mg, and pH in the soil Oe horizon. Mg was increased in the B horizon when comparing the plots receiving N with those receiving CaMg. In mature trees, foliar Ca and Mg concentrations were higher in the CaMg and N+CaMg plots than in the reference or N plots; foliar Ca concentration was higher in the N+CaMg plots compared with the CaMg plots, foliar Mg was higher in the CaMg plots than the N+CaMg plots; An-max was maximized due to N+CaMg treatment; Aqe decreased by N addition; and PAR at An-max increased by N or CaMg treatments alone, but the increase was maximized by their combination. No treatment effect was detected on basal areas of living mature trees four or eight years after treatment applications. In seedlings, An-max was increased by N+CaMg addition. The reference plots had an open herbaceous layer, but the plots receiving N had a dense monoculture of common woodfern in the forest floor

  6. Nitrogen Recovered By Sorghum Plants As Affected By Saline Irrigation Water And Organic/Inorganic Resources Using 15N Technique

    International Nuclear Information System (INIS)

    A pot experiment was conducted in the green house of Soil and Water Department, Nuclear Research Centre, Atomic Energy Authority, Egypt, to follow up the effect of saline irrigation water, inorganic and organic fertilizers on sorghum growth and N fractions that recovered by plant organs. Two types of artificial water salinity were used; one has 3 dS m-1 salinity level with 4 and 8 SAR and the second one has 3 and 6 dS m-1 salinity levels with 6 SAR . Leucenae residue and chicken manure were applied as organic sources at rate of 2% v/v. Sorghum was fertilized with recommended doses of super phosphate and potassium sulfate at rate of 150 kg P and 50 kg K per feddan, respectively. Labelled ammonium sulfate with 5% 15N atom excess was applied to sorghum at rate of 100 kg N fed-1. Dry matter yield (stalks and roots) was negatively affected by increasing water salinity levels or SAR ratios. Similar trend was recorded with N uptake by either stalks or roots of sorghum plants. On the other hand, both the dry matter yield and N uptake were positively and significantly affected by incorporation of organic sources in comparison to the untreated control. In this regard, the dry matter yield and N uptake induced by incorporation of chicken manure was superior over those recorded with leucenae residues. It means, in general, that the incorporation of organic sources into the soil may maximize the plant ability to combat the hazards effects caused by irrigation with saline water. Nitrogen derived from fertilizer (% Ndff), soil (% Ndfs) and organic resources (% Ndfr) showed frequent trends as affected by water salinity and organic resources but in most cases, severe reduction of these values was recorded when plants were irrigated with saline water. In the same time, plants were more dependent on N derived from organic sources than those derived from mineral fertilizer. Superiority of one organic source over the other was related to water salinity levels and SAR ratios applied in

  7. Synthesis, Characterization, and Tribological Evaluation of TiO2-Reinforced Boron and Nitrogen co-Doped Reduced Graphene Oxide Based Hybrid Nanomaterials as Efficient Antiwear Lubricant Additives.

    Science.gov (United States)

    Jaiswal, Vinay; Kalyani; Umrao, Sima; Rastogi, Rashmi B; Kumar, Rajesh; Srivastava, Anchal

    2016-05-11

    The microwave-synthesized reduced graphene oxide (MRG), boron-doped reduced graphene oxide (B-MRG), nitrogen-doped reduced graphene oxide (N-MRG), boron-nitrogen-co-doped reduced graphene oxide (B-N-MRG), and TiO2-reinforced B-N-MRG (TiO2-B-N-MRG) nanomaterials have been synthesized and characterized by various state-of-the-art techniques, like Raman spectroscopy, powder X-ray diffraction, scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy, high-resolution transmission electron microscopy, and X-ray photoelectron spectroscopy. Furthermore, the tribological properties of prepared nanomaterials as antiwear additives in neutral paraffin oil have been evaluated using a four-ball machine at an optimized additive concentration (0.15% w/v). The tribological parameters, like mean wear scar diameter, coefficient of friction, and wear rates, revealed that these nanomaterials have potential to be developed as environmentally friendly sulfated-ash-, phosphorus-, and sulfur-free antiwear lubricant additives. The friction- and wear-reducing behavior of MRG increased upon successive doping of nitrogen, boron, and both nitrogen and boron. Among these additives, B-N-co-doped MRG shows superior tribological behavior in paraffin base oil. Besides this, the load-carrying properties of B-N-co-doped MRG have significantly improved after its reinforcement with TiO2 nanoparticles. A comparative study of the surface morphology of a lubricated track in the presence of various additives has been assessed by SEM and contact-mode atomic force microscopy. The X-ray photoelectron spectroscopy studies have proved that the excellent lubrication properties of TiO2-B-N-MRG are due to the in situ formation of a tribofilm composed of boron nitride, adsorbed graphene layers, and tribosintered TiO2 nanoparticles during the tribocontact. Being sulfur-, halogen-, and phosphorus-free, these graphene-based nanomaterials act as green antiwear additives, protecting interacting

  8. Corn silage hybrid type and quality of alfalfa hay affect dietary nitrogen utilization by early lactating dairy cows.

    Science.gov (United States)

    Holt, M S; Neal, K; Eun, J-S; Young, A J; Hall, J O; Nestor, K E

    2013-10-01

    This experiment was conducted to determine the effects of corn silage (CS) hybrids and quality of alfalfa hay (AH) in high-forage dairy diets on N utilization, ruminal fermentation, and lactational performance by early-lactating dairy cows. Eight multiparous Holstein cows were used in a duplicated 4 × 4 Latin square experiment with a 2 × 2 factorial arrangement of dietary treatments. The 8 cows (average days in milk = 23 ± 11.2) were surgically fitted with ruminal cannula, and the 2 squares were conducted simultaneously. Within square, cows were randomly assigned to a sequence of 4 diets: conventional CS (CCS) or brown midrib CS (BMR) was combined with fair-quality AH [FAH: 46.7% neutral detergent fiber (NDF) and 18.4% crude protein (CP)] or high-quality AH (HAH: 39.2% NDF and 20.7% CP) to form 4 treatments: CCS with FAH, CCS with HAH, BMR with FAH, and BMR with HAH. Diets were isonitrogenous across treatments, averaging 15.9% CP. Each period lasted a total of 21 d, with 14 d for treatment adaptation and 7d for data collection and sampling. Intake of DM and milk yield did not differ in response to CS hybrids or AH quality. Although feeding BMR-based diets decreased urinary N output by 24%, it did not affect fecal N output. Feeding HAH decreased urinary N output by 15% but increased fecal N output by 20%. Nitrogen efficiency [milk N (g/d)/intake N (g/d)] tended to increase for BMR treatments. Ruminal ammonia-N concentration was lower for cows fed BMR-based diets than for those fed CCS-based diets but was not affected by quality of AH. Feeding BMR-based diets or HAH decreased milk urea N concentration by 23 or 15%, respectively, compared with CCS-based diets or FAH. Total volatile fatty acid concentration increased with HAH but was not influenced by CS hybrids. Feeding BMR-based diets decreased urinary N-to-fecal N ratio (UN:FN), and it was further reduced by feeding HAH. Although cows fed the BMR-based diets tended to increase milk N-to-manure N ratio, the

  9. Sensory aroma characteristics of alcalase hydrolyzed rice bran protein concentrate as affected by spray drying and sugar addition.

    Science.gov (United States)

    Arsa, Supeeraya; Theerakulkait, Chockchai

    2015-08-01

    The sensory aroma characteristics of alcalase hydrolyzed rice bran protein concentrate as affected by spray drying and sugar addition were investigated. Rice bran protein concentrate (RBPC) was hydrolyzed by alcalase. Sucrose, glucose or fructose was added to the liquid rice bran protein hydrolysate (LRBPH) and subsequently spray dried. The sensory aroma intensities of the hydrolysates were evaluated. Results showed that after spray drying, the rice bran protein concentrate powder (RBPC-P) had higher sweet and cocoa-like aroma intensities than RBPC (p ≤ 0.05) and hydrolyzed rice bran protein powder (HRBPP) had higher milk powder-like aroma intensities than LRBPH (p ≤ 0.05). The sweet, cocoa-like and milk powder-like aroma intensities in hydrolyzed rice bran protein powder with fructose addition (HRBPP-F) were significantly higher (p ≤ 0.05) than those of hydrolyzed rice bran protein powder with sucrose or glucose addition (HRBPP-S or HRBPP-G). HRBPP-F had the highest overall aroma liking score. These results also indicate that spray drying and sugar addition could improve the sensory aroma characteristics of alcalase hydrolyzed RBPC. PMID:26243954

  10. Role of nitrogen addition in stabilizing the γ phase of Biomedical Co–29Cr–6Mo alloy

    International Nuclear Information System (INIS)

    Highlights: ► 3-D atomic probe observation + thermodynamic calculations. ► N addition does not change the Gibbs energy of alloy system greatly. ► Generate the energy barrier by formation of N–Cr cluster. ► N addition stabilizes the γ phase of Co–Cr–Mo alloy. ► Phase transition slows down but the transition point does not change with N addition. - Abstract: Three-dimensional atom probe observations and thermodynamic calculations revealed that the mechanism of γ-phase stabilization by N addition in the Co–29Cr–6Mo alloy is different from that in stainless steel: N addition does not lower the free energy of the γ phase in Co–29Cr–6Mo but increases the energy barrier and thus lowers the kinetic rate of the γ → ε transition through the formation of Cr–N short range order.

  11. Root-zone acidity and nitrogen source affects Typha latifolia L. growth and uptake kinetics of ammonium and nitrate.

    Science.gov (United States)

    Brix, Hans; Dyhr-Jensen, Kirsten; Lorenzen, Bent

    2002-12-01

    The NH(4)(+) and NO(3)(-) uptake kinetics by Typha latifolia L. were studied after prolonged hydroponics growth at constant pH 3.5, 5.0, 6.5 or 7.0 and with NH(4)(+) or NO(3)(-) as the sole N-source. In addition, the effects of pH and N source on H(+) extrusion and adenine nucleotide content were examined. Typha latifolia was able to grow with both N sources at near neutral pH levels, but the plants had higher relative growth rates, higher tissue concentrations of the major nutrients, higher contents of adenine nucleotides, and higher affinity for uptake of inorganic nitrogen when grown on NH(4)(+). Growth almost completely stopped at pH 3.5, irrespective of N source, probably as a consequence of pH effects on plasma membrane integrity and H(+) influx into the root cells. Tissue concentrations of the major nutrients and adenine nucleotides were severely reduced at low pH, and the uptake capacity for inorganic nitrogen was low, and more so for NO(3)(-)-fed than for NH(4)(+)-fed plants. The maximum uptake rate, V(max), was highest for NH(4)(+) at pH 6.5 (30.9 micro mol h(-1) g(-1) root dry weight) and for NO(3)(-) at pH 5.0 (31.7 micro mol h(-1) g(-1) root dry weight), and less than 10% of these values at pH 3.5. The affinity for uptake as estimated by the half saturation constant, K((1/2)), was lowest at low pH for NH(4)(+) and at high pH for NO(3)(-). The changes in V(max) and K((1/2)) were thus consistent with the theory of increasing competition between cations and H(+) at low pH and between anions and OH(-) at high pH. C(min) was independent of pH, but slightly higher for NO(3)(-) than for NH(4)(+) (C(min)(NH(4)(+)) approximately 0.8 mmol m(-3); C(min)(NO(3)(-)) approximately 2.8 mmol m(-3)). The growth inhibition at low pH was probably due to a reduced nutrient uptake and a consequential limitation of growth by nutrient stress. Typha latifolia seems to be well adapted to growth in wetland soils where NH(4)(+) is the prevailing nitrogen compound, but very low p

  12. Experimental and numerical studies of the effects of hydrogen addition on the structure of a laminar methane-nitrogen jet in hot coflow under MILD conditions

    NARCIS (Netherlands)

    Sepman, Alexey; Abtahizadeh, Ebrahim; Mokhov, Anatoli; van Oijen, Jeroen; Levinsky, Howard; de Goey, Philip

    2013-01-01

    In this work we investigate the effects of hydrogen addition on the flame structure of MILD combustion both experimentally and numerically using a laminar-jet-in-hot-coflow (LJHC) geometry. The addition of hydrogen appreciably decreases the flame height (similar to 25%), however only modestly affect

  13. Nitrogen and oxygen functionalized hollow carbon materials: The capacitive enhancement by simply incorporating novel redox additives into H2SO4 electrolyte

    Science.gov (United States)

    Nie, Yong Fu; Wang, Qian; Chen, Xiang Ying; Zhang, Zhong Jie

    2016-07-01

    In present work, we have developed a simple but effective template carbonization method for producing hollow carbon materials with high content of nitrogen and oxygen from thiocarbanilide. Among all samples, the NPC-1 exhibits high specific surface area (736 m2 g-1) and large pore volume (5.93 cm3 g-1) with high content of heteroatoms (∼11.25 at% nitrogen and ∼5.74 at% oxygen), which is conducive to the improvement of electrochemical performance. Specifically, the high specific capacitance and excellent cycling stability over 5000 cycles of the NPC-1-based electrode are achieved in 1 mol L-1 H2SO4 electrolyte. Additionally, pyrocatechol and rutin as novel redox additives that can easily cause redox-reactions have been incorporated into H2SO4 electrolyte to improve the capacitances. As a result, the NPC-1-R-0.15 and NPC-1-P-0.15 samples deliver high specific capacitances of 120.5 and 368.7 F g-1 at 2 A g-1, respectively, which are much higher than that of the NPC-1 sample (66.2 F g-1) without redox-additives at same current density. Furthermore, the large energy density of 18.9 and 11.9 Wh kg-1 of the NPC-1-based symmetric supercapacitors have been obtained in H2SO4+pyrocatechol and H2SO4+rutin electrolyte, respectively, and both samples also demonstrate excellent cyclic performance for 5000 cycles.

  14. Plant Functional Diversity Can Be Independent of Species Diversity: Observations Based on the Impact of 4-Yrs of Nitrogen and Phosphorus Additions in an Alpine Meadow

    OpenAIRE

    Wei Li; Ji-Min Cheng; Kai-Liang Yu; Howard E. Epstein; Liang Guo; Guang-Hua Jing; Jie Zhao; Guo-Zhen Du

    2015-01-01

    Past studies have widely documented the decrease in species diversity in response to addition of nutrients, however functional diversity is often independent from species diversity. In this study, we conducted a field experiment to examine the effect of nitrogen and phosphorus fertilization ((NH4)2 HPO4) at 0, 15, 30 and 60 g m-2 yr-1 (F0, F15, F30 and F60) after 4 years of continuous fertilization on functional diversity and species diversity, and its relationship with productivity in an alp...

  15. Cotton responses to simulated insect damage: radiation-use efficiency, canopy architecture and leaf nitrogen content as affected by loss of reproductive organs

    International Nuclear Information System (INIS)

    Key cotton pests feed preferentially on reproductive organs which are normally shed after injury. Loss of reproductive organs in cotton may decrease the rate of leaf nitrogen depletion associated with fruit growth and increase nitrogen uptake and reduction by extending the period of root and leaf growth compared with undamaged plants. Higher levels of leaf nitrogen resulting from more assimilation and less depletion could increase the photosynthetic capacity of damaged crops in relation to undamaged controls. To test this hypothesis, radiation-use efficiency (RUE = g dry matter per MJ of photosynthetically active radiation intercepted by the canopy) of crops in which flowerbuds and young fruits were manually removed was compared with that of undamaged controls. Removal of fruiting structures did not affect RUE when cotton was grown at low nitrogen supply and high plant density. In contrast, under high nitrogen supply and low plant density, fruit removal increased seasonal RUE by 20–27% compared to controls. Whole canopy measurements, however, failed to detect the expected variations in foliar nitrogen due to damage. Differences in RUE between damaged and undamaged canopies were in part associated with changes in plant and canopy structure (viz. internode number and length, canopy height, branch angle) that modified light distribution within the canopy. These structural responses and their influence on canopy light penetration and photosynthesis are synthetised in coefficients of light extinction (k) that were 10 to 30% smaller in damaged crops than in controls and in a positive correlation between RUE−1 and k for crops grown under favourable conditions (i.e. high nitrogen, low density). Changes in plant structure and their effects on canopy architecture and RUE should be considered in the analysis of cotton growth after damage by insects that induce abscission of reproductive organs. (author)

  16. Role of nitrogen addition in stabilizing the {gamma} phase of Biomedical Co-29Cr-6Mo alloy

    Energy Technology Data Exchange (ETDEWEB)

    Li, Y.P., E-mail: lyping@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, Aoba-ku, Katahira 2-1-1, Sendai, 980-8577 (Japan); Yu, J.S. [Department of Materials Science and Engineering, National University of Defense Technology, Changsha, Hunan (China); Kurosu, S.; Koizumi, Y. [Institute for Materials Research, Tohoku University, Aoba-ku, Katahira 2-1-1, Sendai, 980-8577 (Japan); Matsumoto, H. [Institute for Materials Research, Tohoku University, Aoba-ku, Katahira 2-1-1, Sendai, 980-8577 (Japan); Department of Materials Science and Engineering, National University of Defense Technology, Changsha, Hunan (China); Chiba, A. [Institute for Materials Research, Tohoku University, Aoba-ku, Katahira 2-1-1, Sendai, 980-8577 (Japan)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer 3-D atomic probe observation + thermodynamic calculations. Black-Right-Pointing-Pointer N addition does not change the Gibbs energy of alloy system greatly. Black-Right-Pointing-Pointer Generate the energy barrier by formation of N-Cr cluster. Black-Right-Pointing-Pointer N addition stabilizes the {gamma} phase of Co-Cr-Mo alloy. Black-Right-Pointing-Pointer Phase transition slows down but the transition point does not change with N addition. - Abstract: Three-dimensional atom probe observations and thermodynamic calculations revealed that the mechanism of {gamma}-phase stabilization by N addition in the Co-29Cr-6Mo alloy is different from that in stainless steel: N addition does not lower the free energy of the {gamma} phase in Co-29Cr-6Mo but increases the energy barrier and thus lowers the kinetic rate of the {gamma} {yields} {epsilon} transition through the formation of Cr-N short range order.

  17. Improvement of phenolic antioxidants and quality characteristics of virgin olive oil with the addition of enzymes and nitrogen during olive paste processing

    Directory of Open Access Journals (Sweden)

    Iconomou, D.

    2010-09-01

    Full Text Available The evolution of phenolic compounds and their contribution to the quality characteristics in virgin olive oil during fruit processing was studied with the addition of a combination of various commercial enzymes containing pectinases, polygalacturonases, cellulase and β-glucanase with or without nitrogen flush. Olive fruits (Olea europaea, L. of the cultivar Megaritiki, at the semi black pigmentation stage of maturity, were used in a 3-phase extraction system in an experiment at industrial scale. The addition of enzymes in the olive paste during processing increased the total phenol and ortho-diphenol contents, as well as some simple phenolic compounds (3,4-DHPEA, p-HPEA and the secoiridoid derivatives (3,4-DHPEA-EDA and 3,4-DHPEAEA in olive oil and therefore improved its oxidative stability. Furthermore, enzyme treatment ameliorated the quality parameters of the produced olive oil (acidity and peroxide value and their sensory attributes. The use of additional N2 flush with the enzyme treatments did not improve the quality parameters of olive oil any further; however it did not affect the concentration of individual and total sterols or most of the fatty acid composition. Consequently, olive paste treatment with enzymes not only improved the quality characteristics of olive oil and enhanced the overall ogranoleptic quality, but also increased the olive oil yield.

    La evolución de los compuestos fenólicos y su contribución a las caracterísiticas de calidad de aceite de oliva virgen durante el procesado del fruto fue estudiado mediante la adición de una combinación de varias enzimas comerciales conteniendo pectinasas, poligalacturonasa, celulasa y β-glucanasa con y sin flujo de nitrógeno. Las aceitunas (Olea europaea, L. de la variedad Megaritiki, con un estado de madurez correspondiente a una pigmentación semi-negra, fueron usadas en un experimento a escala industrial mediante un sistema de extracción de 3-fase. La

  18. Further improvement in ganoderic acid production in static liquid culture of Ganoderma lucidum by integrating nitrogen limitation and calcium ion addition.

    Science.gov (United States)

    Li, Huan-Jun; Zhang, De-Huai; Han, Li-Liang; Yu, Xuya; Zhao, Peng; Li, Tao; Zhong, Jian-Jiang; Xu, Jun-Wei

    2016-01-01

    To further improve the ganoderic acid (GA) production, a novel integrated strategy by combining nitrogen limitation and calcium ion addition was developed. The effects of the integrated combination on the content of GA-T (one powerful anticancer compound), their intermediates (squalene and lanosterol) and on the transcription levels of GA biosynthetic genes in G. lucidum fermentation were investigated. The maximum GA-T content with the integrated strategy were 1.87 mg/ 100 mg dry cell weight, which was 2.1-4.2 fold higher than that obtained with either calcium ion addition or nitrogen limitation alone, and it is also the highest record as ever reported in submerged fermentation of G. lucidum. The squalene content was increased by 3.9- and 2.2-fold in this case compared with either individual strategy alone. Moreover, the transcription levels of the GA biosynthetic genes encoding 3-hydroxy-3-methyglutaryl coenzyme A reductase and lanosterol synthase were also up-regulated by 3.3-7.5 and 1.3-2.3 fold, respectively. PMID:26508324

  19. Influence of Residue and Nitrogen Fertilizer Additions on Carbon Mineralization in Soils with Different Texture and Cropping Histories

    OpenAIRE

    Xianni Chen; Xudong Wang; Matt Liebman; Michel Cavigelli; Michelle Wander

    2014-01-01

    To improve our ability to predict SOC mineralization response to residue and N additions in soils with different inherent and dynamic organic matter properties, a 330-day incubation was conducted using samples from two long-term experiments (clay loam Mollisols in Iowa [IAsoil] and silt loam Ultisols in Maryland [MDsoil]) comparing conventional grain systems (Conv) amended with inorganic fertilizers with 3 yr (Med) and longer (Long), more diverse cropping systems amended with manure. A double...

  20. Effects of nitrogen additions on biomass, stoichiometry and nutrient pools of moss Rhytidium rugosum in a boreal forest in Northeast China

    International Nuclear Information System (INIS)

    Global nitrogen (N) deposition has been enhanced with anthropogenic N emissions, and its impacts on mosses are receiving more and more attention. This study investigates how N deposition influence the biomass and stoichiometry of moss Rhytidium rugosum, using a 3-year N enrichment experiment with 0, 2, 5 and 10 g N m−2 yr−1 in a boreal forest in Northeast China. Low N additions caused an N redundancy and moderate to high N additions resulted in a biomass loss. N additions reduced biomass ratios of green to brown tissues and increased N and phosphorus (P) contents, suggesting changes in photosynthetic capacity and litter decomposition. Biomass N pools showed a unimodal response to the N additions, and P pools decreased under moderate and high N additions. Our findings indicate significant stoichiometric and biomass changes caused by N deposition may lead to a substantial carbon and nutrient loss in boreal moss carpets. - Highlights: • Effects of N deposition on moss biomass and stoichiometry were investigated. • N deposition reduced biomass ratios of green to brown moss tissues. • N deposition increased N and P contents in moss tissues. • N deposition caused significant changes of moss carbon and nutrient pools. - Significant stoichiometric and biomass changes of mosses can be caused by N deposition and may lead to a substantial carbon and nutrient loss in boreal moss carpets

  1. 氮添加对生长季寒温带针叶林土壤有效氮和酸化的影响%Effects of Nitrogen Addition on Available Nitrogen Content and Acidification in Cold-temperate Coniferous Forest Soil in the Growing Season

    Institute of Scientific and Technical Information of China (English)

    陈高起; 傅瓦利; 罗亚晨; 高文龙; 李胜功; 杨浩

    2014-01-01

    +4 -N content in 0-10 cm soil were more obvious in the early growing season than that in the peak growing season, and the NH +4 -N content was mainly affected by the type of nitrogen addition. On the contrary, the NO -3 -N content in 0-10 cm soil was higher in the peak growing season than that in the early growing season. The effect of N input was obvious on NO -3 -N content in both early and peak growing seasons, and low nitrogen treatment tended to promote the enrichment of NO -3 -N. As time went on, the response of NH +4 -N and NO -3 -N content to N addition was changed from insignificant in the early stage to significant in the late stage. N addition had a significant impact on the pH value of the 0-10 cm soil in the early and peak growing seasons. The pH values of the soil with low nitrogen treatment and the soil in the peak growing season were relatively lower. With the extension of the nitrogen addition time, the response of pH value also turned from insignificant in the early stage to significant in the late stage. Because of the long-term and continuous nitrogen addition, the 0- 10 cm soil in this cold-temperate coniferous forest was obviously acidified.

  2. Absorption of applied zinc(Zn65) as affected by nitrogen and amendments in normal and saline-sodic zinc

    International Nuclear Information System (INIS)

    The absorption of applied zinc (Zn65) by corn plants in saline sodic-soils of different pHs was studied. The effect of NH4NO3 and gypsum in this respect was also investigated. Nitrogen application with Zn increased the concentration of Zn in the plants irrespective of the soil character. In saline-sodic soils, the application of gypsum was more effective than nitrogen. Gypsum application followed by leaching with water increased the concentration of Zn as compared to gypsum application without leaching, indicating that the presence of sodium in exchangeable or soluble forms decreases the absorption of Zn by plants. (author)

  3. The influence of nitrogen and oxygen additions on the thermal characteristics of aluminium-based thin films

    International Nuclear Information System (INIS)

    The ternary aluminium oxynitride (AlNxOy) system offers the possibility to obtain a wide range of properties by tailoring the ratio between pure Al, AlNx and AlOy and therefore opening a significant number of possible applications. In this work the thermal behaviour of AlNxOy thin films was analysed by modulated infrared radiometry (MIRR), taking as reference the binary AlOy and AlNx systems. MIRR is a non-contact and non-destructive thermal wave measurement technique based on the excitation, propagation and detection of temperature oscillations of very small amplitudes. The intended change of the partial pressure of the reactive gas (N2 and/or O2) influenced the target condition and hence the deposition characteristics which, altogether, affected the composition and microstructure of the films. Based on the MIRR measurements and their qualitative and quantitative interpretation, some correlations between the thermal transport properties of the films and their chemical/physical properties have been found. Furthermore, the potential of such technique applied in this oxynitride system, which present a wide range of different physical responses, is also discussed. The experimental results obtained are consistent with those reported in previous works and show a high potential to fulfil the demands needed for the possible applications of the systems studied. They are clearly indicative of an adequate thermal response if this particular thin film system is aimed to be applied in small sensor devices or in electrodes for biosignal acquisition, such as those for electroencephalography or electromyography as it is the case of the main research area that is being developed in the group. - Highlights: • AlNx, AlOy and AlNxOy films were deposited by magnetron sputtering. • Discharge characteristics were compared between systems. • Different x and y coefficients were obtained. • Composition, structure and morphology were correlated with physical properties. • Thermal

  4. Nitrogen use efficiencies of drip-irrigated tomatoes and peppers as affected by soil application and fertigation

    International Nuclear Information System (INIS)

    This greenhouse study conducted on a Mediterranean Terra Rose soil in an unheated plastic greenhouse was designed to investigate the response of drip-irrigated tomatoes (Lycopersicon esculentum Mill.) and peppers (Capsicum annum) to four nitrogen levels continually applied with irrigation stream. Water containing 0,67,134 or 201 mgN/l and uniformly supplied with 80 and 240 mg/l of P and K, respectively, were applied two times a week. Three adjacent plants in each plot were fertigated with N15 labeled NH4S2O4 (2% a.e. enrichment). For each plant the amount of water, P, K and the N15 applied through the bottles was to that amount applied through a single dripper. In addition to the fertigation soil application of 400 kgN/ha was included with three adjacent plants in each plot were fertilized receiving N15 labeled (3.3 % a.e. enrichment) The total amount of water applied was 392 mm and the resulting N application totals ranged from 200 to 600 kgN/ha. According to the results obtained, the maximum yield of tomatoes and peppers were achieved with 67 mgN/l (200 kgN/ha) treatment. The percentage fertilizer utilization by tomatoes was highest with 67 mgN/l (200 kgN/ha), which was followed by 134 mgN/l (400 kgN/ha) .The percentage fertilizer utilization was the lowest with 201 mgN/l (600 kgN/ha) or soil application (400 kgN/ha). The results indicated that the percentage fertilizer utilization of tomatoes was significantly greater by the fertigation than the soil application of N at the same level fertilization (400 kgN/ha). The fertilizer N uptake by peppers was significantly greater with 134 mgN/l (400 kgN/ha) than the other applications. The results indicated that although the percentage fertilizer utilization was the same, the fertilizer N uptake by peppers was significantly greater with the fertigation than the soil application of N at the same level fertilization (400 kgN/ha)

  5. Alteration of the Fates and Fluxes of Nitrogen by Detritivorous Fish: a Whole-Stream Manipulation and a 15N-tracer Addition

    Science.gov (United States)

    Taylor, B. W.; Hall, R. O.; Flecker, A. S.; Fisher, C. A.; Grant, M. B.; Jeffs, L.; Richmond, E. L.; Thomas, S. A.

    2005-05-01

    The key roles played by a few species and the non-random order of human-induced biodiversity loss provide compelling reasons for predicting the consequences of individual species losses on ecosystem functioning. This is especially true for vertebrates such as fish that are more vulnerable to extinction and are often over-harvested. Here we test the consequences of losing a single detritivorous fish species, Prochilodus mariae that constitutes 80% of the South American freshwater fishery and is declining. We used a large-scale experimental approach to remove Prochilodus from a diverse assemblage, and measured the effects of its loss on the stream nitrogen cycle using a 15NH4-N addition during years with high and low fish abundance. There was no difference in gross uptake of dissolved 15NH4-N, but when detritivorous fish were present nitrification was 30% higher. The flux of nitrogen into fine benthic particulate compartments was 46% greater when detritivorous fish were removed, but long-term N loss was much higher from these compartments. In contrast, in the presence of detritivorous fish N was retained by more stable epilithic biofilms. In the ecologically intact system, detritivorous fish influence the fates and fluxes of N, which increases N storage by this headwater stream.

  6. Impact of high microwave power on hydrogen impurity trapping in nanocrystalline diamond films grown with simultaneous nitrogen and oxygen addition into methane/hydrogen plasma

    Science.gov (United States)

    Tang, C. J.; Fernandes, A. J. S.; Jiang, X. F.; Pinto, J. L.; Ye, H.

    2016-01-01

    In this work, we study for the first time the influence of microwave power higher than 2.0 kW on bonded hydrogen impurity incorporation (form and content) in nanocrystalline diamond (NCD) films grown in a 5 kW MPCVD reactor. The NCD samples of different thickness ranging from 25 to 205 μm were obtained through a small amount of simultaneous nitrogen and oxygen addition into conventional about 4% methane in hydrogen reactants by keeping the other operating parameters in the same range as that typically used for the growth of large-grained polycrystalline diamond films. Specific hydrogen point defect in the NCD films is analyzed by using Fourier-transform infrared (FTIR) spectroscopy. When the other operating parameters are kept constant (mainly the input gases), with increasing of microwave power from 2.0 to 3.2 kW (the pressure was increased slightly in order to stabilize the plasma ball of the same size), which simultaneously resulting in the rise of substrate temperature more than 100 °C, the growth rate of the NCD films increases one order of magnitude from 0.3 to 3.0 μm/h, while the content of hydrogen impurity trapped in the NCD films during the growth process decreases with power. It has also been found that a new H related infrared absorption peak appears at 2834 cm-1 in the NCD films grown with a small amount of nitrogen and oxygen addition at power higher than 2.0 kW and increases with power higher than 3.0 kW. According to these new experimental results, the role of high microwave power on diamond growth and hydrogen impurity incorporation is discussed based on the standard growth mechanism of CVD diamonds using CH4/H2 gas mixtures. Our current experimental findings shed light into the incorporation mechanism of hydrogen impurity in NCD films grown with a small amount of nitrogen and oxygen addition into methane/hydrogen plasma.

  7. The influence of nitrogen and oxygen additions on the thermal characteristics of aluminium-based thin films

    Energy Technology Data Exchange (ETDEWEB)

    Borges, J., E-mail: joelborges@fisica.uminho.pt [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, Prague 6 (Czech Republic); Macedo, F. [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Couto, F.M. [Physics Sciences Laboratory, Norte Fluminense State University, 28013-602 Campos–RJ (Brazil); Rodrigues, M.S.; Lopes, C. [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); Instituto Pedro Nunes, Laboratório de Ensaios, Desgaste e Materiais, Rua Pedro Nunes, 3030-199 Coimbra (Portugal); Pedrosa, P. [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal); SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); Universidade do Porto, Faculdade de Engenharia, Departamento de Engenharia Metalúrgica e de Materiais, Rua Dr. Roberto Frias, s/n, 4200-465 Porto (Portugal); Polcar, T. [Department of Control Engineering, Faculty of Electrical Engineering, Czech Technical University in Prague, Technická 2, Prague 6 (Czech Republic); Engineering Materials & nCATS, FEE, University of Southampton, Highfield Campus, SO17 1BJ, Southampton (United Kingdom); Marques, L.; Vaz, F. [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710-057 Braga (Portugal)

    2015-08-01

    The ternary aluminium oxynitride (AlN{sub x}O{sub y}) system offers the possibility to obtain a wide range of properties by tailoring the ratio between pure Al, AlN{sub x} and AlO{sub y} and therefore opening a significant number of possible applications. In this work the thermal behaviour of AlN{sub x}O{sub y} thin films was analysed by modulated infrared radiometry (MIRR), taking as reference the binary AlO{sub y} and AlN{sub x} systems. MIRR is a non-contact and non-destructive thermal wave measurement technique based on the excitation, propagation and detection of temperature oscillations of very small amplitudes. The intended change of the partial pressure of the reactive gas (N{sub 2} and/or O{sub 2}) influenced the target condition and hence the deposition characteristics which, altogether, affected the composition and microstructure of the films. Based on the MIRR measurements and their qualitative and quantitative interpretation, some correlations between the thermal transport properties of the films and their chemical/physical properties have been found. Furthermore, the potential of such technique applied in this oxynitride system, which present a wide range of different physical responses, is also discussed. The experimental results obtained are consistent with those reported in previous works and show a high potential to fulfil the demands needed for the possible applications of the systems studied. They are clearly indicative of an adequate thermal response if this particular thin film system is aimed to be applied in small sensor devices or in electrodes for biosignal acquisition, such as those for electroencephalography or electromyography as it is the case of the main research area that is being developed in the group. - Highlights: • AlN{sub x}, AlO{sub y} and AlN{sub x}O{sub y} films were deposited by magnetron sputtering. • Discharge characteristics were compared between systems. • Different x and y coefficients were obtained.

  8. Integrated use of plant growth promoting rhizobacteria, biogas slurry and chemical nitrogen for sustainable production of maize under salt-affected conditions

    International Nuclear Information System (INIS)

    Salinity is one of the most critical constraints hampering agricultural production throughout the world, including Pakistan. Some plant growth promoting rhizobacteria (PGPR) have the ability to reduce the deleterious effect of salinity on plants due to the presence of ACC-deaminase enzyme along with some other mechanisms. The integrated use of organic, chemical and biofertilizers can reduce dependence on expensive chemical inputs. To sustain high crop yields without deterioration of soil fertility, it is important to work out optimal combination of chemical and biofertilizers, and manures in the cropping system. A pot trial was conducted to study the effect of integrated use of PGPR, chemical nitrogen, and biogas slurry for sustainable production of maize under salt-stressed conditions and for good soil health. Results showed that sole application of PGPR, chemical nitrogen and biogas slurry enhanced maize growth but their combined application was more effective. Maximum improvement in maize growth, yield, ionic concentration in leaves and nutrient concentration in grains was observed in the treatment where PGPR and biogas slurry was used in the presence of 100% recommended nitrogen as chemical fertilizer. It also improved the soil pH, ECe, and available N, P and K contents. It is concluded that integrated use of PGPR, biogas slurry and chemical nitrogen not only enhanced maize growth, yield and quality but also improved soil health. So, it may be evaluated under field conditions to get sustained yield of maize from salt-affected soils. (author)

  9. CHARACTERISTICS OF FLUORIDE EMISSION FROM FIVE CLAY MINERALS AS AFFECTED BY TEMPERATURE,HEATING TIME AND ADDITION OF CALCIUM COMPOUNDS

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Characteristics of fluoride emission from five clay minerals (montmorillonite, kaolinite, vermiculite, geothite, and allophane) as affected by temperature, heating time and addition of calcium compounds were studied. Marked increase of the fluoride emission rate was noticed with increase of temperature. The fluoride release, began at 500 ℃-600 ℃, and the main bulk of the fluoride emission occurred at the temperature of about 800 ℃. The loss of crystalline water was primarily responsible for the increase of fluoride emission. When minerals were heated at 800 ℃, The fluoride emission rate from the clay minerals reached the highest after heating for 1 hour. The samples treated by CaO, CaCO3, Ca(OH)2, Ca3(PO4)2, and CaSO4 had 55.45%, 59.58%, 46.45%, 54.31%, 31.25% reduction in the fluoride emission from montmorillonite at the temperature of 800 ℃, respectively. CaCO3 had the highest fluoride fixing capacity compared to other calcium compounds.

  10. Rapid N2O fluxes at high level of nitrate nitrogen addition during freeze-thaw events in boreal peatlands of Northeast China

    Science.gov (United States)

    Cui, Qian; Song, Changchun; Wang, Xianwei; Shi, Fuxi; Wang, Lili; Guo, Yuedong

    2016-06-01

    Freeze-thaw (FT) events and increasing nitrogen (N) availability may alter N turnover and nitrous oxide (N2O) emissions in permafrost peatlands. However, the responses of N2O emissions to different N levels and additions during FT events are far from clear. We conducted an incubation study to investigate the impacts of different N addition levels (LN: 0.07 mg N g-1, HN: 0.14 mg N g-1) and N addition forms (AC: ammonium chloride, NS: sodium nitrate) on the emissions of N2O under FT and non-freeze-thaw (NFT) conditions in boreal peatlands of Northeast China. Results indicated that the FT condition significantly increased N2O emissions compared with the NFT condition and peaks occurred during thawing. Compared with AC treatments, NS treatments significantly elevated the accumulation of N2O emissions under the FT condition, exhibiting significant differences in different NS levels. N2O emissions were also positively dependent on soil NO3- concentrations to supply nitrate for denitrification. Nitrate-N addition was mainly responsible for the burst of N2O with denitrification as the main process during FT events. Therefore, these results suggest that N2O emissions potentially increase during FT events with increasing nitrate-N deposition in permafrost peatlands, which would contribute to global climate warming.

  11. Effects of organic additives with oxygen- and nitrogen-containing functional groups on the negative electrolyte of vanadium redox flow battery

    International Nuclear Information System (INIS)

    DL-malic acid and L-aspartic acid are investigated as additives for the negative electrolyte of vanadium redox flow battery (VFRB) to improve its stability and electrochemical performance. The stability experiments indicate that the addition of L-aspartic acid into the 2 M V(III) electrolyte can stabilize the electrolyte by delaying its precipitation. The results of cyclic voltammetry and electrochemical impedance spectroscopy show that the V(III) electrolyte with both additives demonstrates enhanced electrochemical activity and reversibility. The introduction of DL-malic acid and L-aspartic acid can increase the diffusion coefficient of V(III) species and facilitate the charge transfer of V(III)/V(II) redox reaction. Between the two additives, the effect of L-aspartic acid is more remarkable. Moreover, the VFRB cell employing negative electrolyte with L-aspartic acid exhibits excellent cycling stability and achieves higher average energy efficiency (76.4%) compared to the pristine cell (73.8%). The comparison results with the cell employing L-aspartic acid pre-treated electrode confirm that L-aspartic acid in the electrolyte can modify the electrode by constantly providing oxygen- and nitrogen-containing groups, leading to the enhancement of electrochemical performance

  12. Collembolans feeding on soil affect carbon and nitrogen mineralization by their influence on microbial and nematode activities

    Czech Academy of Sciences Publication Activity Database

    Kaneda, Satoshi; Kaneko, N.

    2008-01-01

    Roč. 44, č. 3 (2008), s. 435-442. ISSN 0178-2762 Institutional research plan: CEZ:AV0Z60660521 Keywords : Collembola * mineral soil * nitrogen mineralization Subject RIV: EH - Ecology, Behaviour Impact factor: 1.446, year: 2008

  13. Minimization of heat-affected zone size in welded ultra-fine grained steel under cooling by liquid nitrogen during laser welding

    International Nuclear Information System (INIS)

    Ultra-fine grained steel (UFGS) with an average grain size of less than 1 μm has been developed and is expected to demonstrate superior mechanical and chemical properties. However, its welded heat-affected zones, HAZ, substantially affecting the strength of a welded joint, will be easily softened after welding. Therefore, minimization of UFGS's HAZ size during laser welding was carried out using the cooling conductor liquid nitrogen. It was found that a shielding gas, with adequate flow rate for the liquid nitrogen depth, was used to remove nitrogen from the area of laser beam irradiation to stabilize the weld bead. Also, the YAG laser system was mainly used because it has a lower temperature, which results in a decreased occurrence of pits and blowholes, of laser induced plasma or plume. HAZ size minimization strongly depends on the initial plate temperature. Reduced initial plate temperature shrinks the specific heated temperature range in which softening occurs. However, under room temperature, due possibly to decreasing thermal conductivity that prevents heat removal from HAZ, the benefit of reducing the initial plate temperature is limited. The optimal initial temperature to minimize the HAZ size was found to be 123 K

  14. Foliar Litter Nitrogen Dynamics as Affected by Forest Gap in the Alpine Forest of Eastern Tibet Plateau

    OpenAIRE

    Wu, Qiqian; Wu, Fuzhong; Yang, Wanqin; Zhao, Yeyi; Wei HE; Tan, Bo

    2014-01-01

    There is increasing attention on the effects of seasonal snowpack on wintertime litter decomposition, as well as the processes following it, in cold biomes. However, little information is available on how litter nitrogen (N) dynamics vary with snowpack variations created by tree crown canopies in alpine forests. Therefore, to understand the effects of seasonal snowpack on litter N dynamics during different critical stages, litterbags with fir (Abies faxoniana), birch (Betula albo-sinensis), l...

  15. Nitrogen ({sup 15}N) accumulation in corn grains as affected by source of nitrogen in red latosol;Acumulo de nitrogenio ({sup 15}N) pelos graos de milho em funcao da fonte nitrogenada em latossolo vermelho

    Energy Technology Data Exchange (ETDEWEB)

    Duete, Robson Rui Cotrim, E-mail: rrcduete@oi.com.b [Empresa Baiana de Desenvolvimento Agricola S.A. (EBDA), Cruz das Almas, BA (Brazil); Muraoka, Takashi; Trivelin, Paulo Cesar Ocheuze; Silva, Edson Cabral da, E-mail: muraoka@cena.usp.b, E-mail: pcotrive@cena.usp.b, E-mail: ecsilva@cena.usp.b [Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil); Ambrosano, Edmilson Jose, E-mail: ambrosano@aptaregional.sp.gov.b [Agencia Paulista de Tecnologia dos Agronegocios (APTA), Piracicaba, SP (Brazil). Polo Centro Sul

    2009-07-01

    Nitrogen is the most absorbed mineral nutrient by corn crop and most affects grains yield. It is the unique nutrient absorbed by plants as cation (NH{sub 4}{sup +}) or anion (NO{sub 3}{sup -}). The objectives of this work were to investigate the N accumulation by corn grains applied to the soil as NH{sub 4}{sup +} or NO{sub 3}{sup -} in the ammonium nitrate form compared to amidic form of the urea, labeled with {sup 15}N; to determine the corn growth stage with highest fertilizer N utilization by the grains, and to quantify soil nitrogen exported by corn grains. The study was carried out in the Experimental Station of the Regional Pole of the Sao Paulo Northwestern Agribusiness Development (APTA), in Votuporanga, State of Sao Paulo, Brazil, in a Red Latosol. The experimental design was completely randomized blocks, with 13 treatments and four replications, disposed in factorial outline 6x2 + 1 (control, without N application). A nitrogen rate equivalent to 120 kg N ha-1 as urea-{sup 15}N or as ammonium nitrate, labeled in the cation NH{sub 4}{sup +} ({sup 15}NH{sub 4}{sup +}NO{sub 3}{sup -}) or in the anion NO{sub 3}{sup -} (NH{sub 4}{sup +}15N+O{sub 3}{sup -} ), was applied in six fractions of 20 kg N ha-1 each, in different microplots, from seeding to the growth stage 7 (pasty grains). The forms of nitrogen, NH{sub 4}{sup +}-N and N{sub O}{sup 3}--N, were accumulated equitably by corn grains. The corn grains accumulated more N from urea than from ammonium nitrate. The N applied to corn crop at eight expanded leaves stage promoted largest accumulation of this nutrient in the grains. (author)

  16. Different aspect of pitting corrosion and interphase corrosion in the weld heat-affected zone of high-nitrogen Fe–18Cr–10Mn–N steel

    International Nuclear Information System (INIS)

    Phase transformation and its effects on corrosion behavior in the weld heat-affected zone (HAZ) of a metastable high-nitrogen Fe–18Cr–10Mn–N austenitic stainless steel were investigated through electrochemical tests, electron probe micro analysis and electron microscopy analysis. Electrochemical tests showed that pitting corrosion and interphase corrosion were significantly affected by δ-ferrite formation in the HAZ and showed changing characteristics with increasing δ-ferrite fraction. Pitting corrosion resistance was reduced by the formation of a Cr-depleted zone along the δ-ferrite/austenite phase boundary due to δ-ferrite formation. However, pitting corrosion resistance did not change with increased peak temperature in the HAZ despite the increasing δ-ferrite fraction. Sensitivity to interphase corrosion was strongly affected by the amount of δ-ferrite/austenite phase boundary and δ-ferrite area, gradually increasing with increasing δ-ferrite fraction. These dissimilar corrosion behaviors were carefully investigated and are discussed in terms of phase transformation and alloying element partitioning in the HAZ. - Highlights: • Corrosion behavior in the weld HAZ of high-nitrogen austenitic steel was examined. • Pitting corrosion and interphase corrosion displays a different aspect. • Pitting corrosion resistance depends on whether or not δ-ferrite forms. • Interphase corrosion resistance depends on the total amount of δ-ferrite

  17. Nitrate reductase activity in cabbage (Brassica oleracae var. capitata seedlings affected by the different nitrogen fertilizer forms

    Directory of Open Access Journals (Sweden)

    Metin Turan

    2013-12-01

    Full Text Available The effect of different nitrogen fertilizer (potassium nitrate, ammonium nitrate, ammonium sulphate, urea and farmyard manure on nitrate reductase activity in cabbage (Brassica oleracea var. capitata seedlings were studied. pH of the plant growth niedia was higher in the nitrate fertilizer treatment than the ammonium and other fertilizer forms. NO3--N application increased NRA in plant, but NH4+-N decreased NRA in plant. Harvesting date and different fertilizer doses increased NRA while NH4+-N decreased plant nitrate uptake. There was a significant relationship between NRA and fertilizer types.

  18. Five-year changes in soil organic carbon and total nitrogen in coastal wetlands affected by flow-sediment regulation in a Chinese delta

    Science.gov (United States)

    Wang, Junjing; Bai, Junhong; Zhao, Qingqing; Lu, Qiongqiong; Xia, Zhijian

    2016-02-01

    Changes in the sources and sinks of soil organic carbon (SOC) and total nitrogen (TN) in wetland soils as indicators of soil quality and climate change have received attention worldwide. Soil samples were collected in 2007 and 2012 in the coastal wetlands of the Yellow River Delta and the SOC and TN were determined to investigate a five-year change in their content and stock in these wetlands as affected by flow-sediment regulation. Our results revealed that the soils in 2007 exhibited greater electrical conductivities, SOC content and density, and ammonium nitrogen (NH4+-N) levels in the top 10 cm soils (p carbon and total nitrogen (molar C/N ratios) were observed in the 30-40 cm soil layer. A significant SOC loss occurred (p < 0.05) in top 10 cm soils, but only a small change in SOC in the top 50 cm soils. Comparatively, TN levels did not show significant differences in the study period.

  19. Five-year changes in soil organic carbon and total nitrogen in coastal wetlands affected by flow-sediment regulation in a Chinese delta

    Science.gov (United States)

    Wang, Junjing; Bai, Junhong; Zhao, Qingqing; Lu, Qiongqiong; Xia, Zhijian

    2016-01-01

    Changes in the sources and sinks of soil organic carbon (SOC) and total nitrogen (TN) in wetland soils as indicators of soil quality and climate change have received attention worldwide. Soil samples were collected in 2007 and 2012 in the coastal wetlands of the Yellow River Delta and the SOC and TN were determined to investigate a five-year change in their content and stock in these wetlands as affected by flow-sediment regulation. Our results revealed that the soils in 2007 exhibited greater electrical conductivities, SOC content and density, and ammonium nitrogen (NH4+-N) levels in the top 10 cm soils (p < 0.05) compared with the soils in 2012. In general, the SOC and TN contents decreased with increasing soil depth. However, the highest ratios of soil organic carbon and total nitrogen (molar C/N ratios) were observed in the 30–40 cm soil layer. A significant SOC loss occurred (p < 0.05) in top 10 cm soils, but only a small change in SOC in the top 50 cm soils. Comparatively, TN levels did not show significant differences in the study period. PMID:26879008

  20. DRD2 and PPP1R1B (DARPP-32) polymorphisms independently confer increased risk for autism spectrum disorders and additively predict affected status in male-only affected sib-pair families

    OpenAIRE

    Hettinger Joe A; Liu Xudong; Hudson Melissa L; Lee Alana; Cohen Ira L; Michaelis Ron C; Schwartz Charles E; Lewis Suzanne ME; Holden Jeanette JA

    2012-01-01

    Abstract Background The neurotransmitter dopamine (DA) modulates executive functions, learning, and emotional processing, all of which are impaired in individuals with autism spectrum disorders (ASDs). Our previous findings suggest a role for dopamine-related genes in families with only affected males. Methods We examined two additional genes which affect DA function, the DRD2 and PPP1R1B (DARPP-32) genes, in a cohort of 112 male-only affected sib-pair families. Selected polymorphisms spannin...

  1. Cr(Vi) reduction capacity of activated sludge as affected by nitrogen and carbon sources, microbial acclimation and cell multiplication

    Energy Technology Data Exchange (ETDEWEB)

    Ferro Orozco, A.M., E-mail: mferro@cidca.org.ar [Centro de Investigacion y Desarrollo en Criotecnologia de Alimentos (CIDCA) CCT La Plata CONICET - Fac. de Cs. Exactas, UNLP. 47 y 116 (B1900AJJ) La Plata (Argentina); Contreras, E.M.; Zaritzky, N.E. [Centro de Investigacion y Desarrollo en Criotecnologia de Alimentos (CIDCA) CCT La Plata CONICET - Fac. de Cs. Exactas, UNLP. 47 y 116 (B1900AJJ) La Plata (Argentina); Fac. de Ingenieria, UNLP. 47 y 1 (B1900AJJ) - La Plata (Argentina)

    2010-04-15

    The objectives of the present work were: (i) to analyze the capacity of activated sludge to reduce hexavalent chromium using different carbon sources as electron donors in batch reactors, (ii) to determine the relationship between biomass growth and the amount of Cr(VI) reduced considering the effect of the nitrogen to carbon source ratio, and (iii) to determine the effect of the Cr(VI) acclimation stage on the performance of the biological chromium reduction assessing the stability of the Cr(VI) reduction capacity of the activated sludge. The highest specific Cr(VI) removal rate (q{sub Cr}) was attained with cheese whey or lactose as electron donors decreasing in the following order: cheese whey {approx} lactose > glucose > citrate > acetate. Batch assays with different nitrogen to carbon source ratio demonstrated that biological Cr(VI) reduction is associated to the cell multiplication phase; as a result, maximum Cr(VI) removal rates occur when there is no substrate limitation. The biomass can be acclimated to the presence of Cr(VI) and generate new cells that maintain the ability to reduce chromate. Therefore, the activated sludge process could be applied to a continuous Cr(VI) removal process.

  2. Cr(Vi) reduction capacity of activated sludge as affected by nitrogen and carbon sources, microbial acclimation and cell multiplication

    International Nuclear Information System (INIS)

    The objectives of the present work were: (i) to analyze the capacity of activated sludge to reduce hexavalent chromium using different carbon sources as electron donors in batch reactors, (ii) to determine the relationship between biomass growth and the amount of Cr(VI) reduced considering the effect of the nitrogen to carbon source ratio, and (iii) to determine the effect of the Cr(VI) acclimation stage on the performance of the biological chromium reduction assessing the stability of the Cr(VI) reduction capacity of the activated sludge. The highest specific Cr(VI) removal rate (qCr) was attained with cheese whey or lactose as electron donors decreasing in the following order: cheese whey ∼ lactose > glucose > citrate > acetate. Batch assays with different nitrogen to carbon source ratio demonstrated that biological Cr(VI) reduction is associated to the cell multiplication phase; as a result, maximum Cr(VI) removal rates occur when there is no substrate limitation. The biomass can be acclimated to the presence of Cr(VI) and generate new cells that maintain the ability to reduce chromate. Therefore, the activated sludge process could be applied to a continuous Cr(VI) removal process.

  3. Water, Nitrogen and Plant Density Affect the Response of Leaf Appearance of Direct Seeded Rice to Thermal Time

    Institute of Scientific and Technical Information of China (English)

    Maite MART(I)NEZ-EIXARCH; ZHU De-feng; Maria del Mar CATAL(A)-FORNER; Eva PLA-MAYOR; Nuria TOM(A)S-NAVARRO

    2013-01-01

    Field experiments were conducted in the Ebro Delta area (Spain),from 2007 to 2009 with two rice varieties:Gleva and Tebre.The experimental treatments included a series of seed rates,two different water management systems and two different nitrogen fertilization times.The number of leaves on the main stems and their emergence time were periodically tagged.The results indicated that the final leaf number on the main stems in the two rice varieties was quite stable over a three-year period despite of the differences in their respective growth cycles.Interaction between nitrogen fertilization and water management influenced the final leaf number on the main stems.Plant density also had a significant influence on the rate of leaf appearance by extending the phyllochron and postponing the onset of intraspecific competition after the emergence of the 7th leaf on the main stems.Final leaf number on the main stems was negatively related to plant density.A relationship between leaf appearance and thermal time was established with a strong nonlinear function.In direct-seeded rice,the length of the phyllochron increases exponentially in line with the advance of plant development.A general model,derived from 2-year experimental data,was developed and satisfactorily validated; it had a root mean square error of 0.3 leaf.An exponential model can be used to predict leaf emergence in direct-seeded rice.

  4. Nitrous oxide emissions from denitrification and the partitioning of gaseous losses as affected by nitrate and carbon addition and soil aeration

    International Nuclear Information System (INIS)

    The factors controlling nitrous oxide (N2O) emissions vary with different soil and environmental conditions and management practices. This study was conducted to determine the importance of soil aeration, nitrate (NO3) addition, carbon (C) additions, and C sources on gaseous nitrogen (N) losses from the denitrification of arable soils at a potato farm in Atlantic Canada. Denitrification and N2O emissions were measured using acetylene inhibition. An N2O and nitrogen gas (N2) ratio of 0.7 showed that most emissions occurred as N2O. Emissions at water-filled pore spaces (WFPs) of 0.45 m3 per m3 were negligible. N2O emissions increased with NO3 and C additions. Results suggested that soil aeration plays a dominant role in controlling the magnitude of denitrification and N2O emissions. However, soil NO3 supplies in this study did not limit the denitrification process. The study showed that N2O emissions are controlled by C availability when there is a high degree of soil disturbance and high fertilizer N inputs. The relationship between the demand and supply of terminal electron acceptors (TEAs) was used to explain the spatial distribution of the N2O emissions. Higher WFPs and lower soil NO3 concentrations resulted in higher rates of total denitrification. It was concluded that further research is needed to examine the role of overall soil and crop management in relation to C availability when developing mitigation strategies. 52 refs., 4 tabs

  5. 76 FR 43699 - List of Additional Lands Affected by White Earth Reservation Land Settlement Act of 1985

    Science.gov (United States)

    2011-07-21

    ...). The first list of such additions was published in the Federal Register on March 27, 1991 (56 FR 12818... (59 FR 17174), and on January 13, 2005 (70 FR 2423.) The list included herein contains more additions... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF THE...

  6. Comparison of Organic Matter Composition in Agricultural versus Forest Affected Headwaters with Special Emphasis on Organic Nitrogen

    DEFF Research Database (Denmark)

    Heinz, Marlen; Graeber, Daniel; Zak, Dominik;

    2015-01-01

    Agricultural management practices promote organic matter (OM) turnover and thus alter both the processing of dissolved organic matter (DOM) in soils and presumably also the export of DOM to headwater streams, which intimately connect the terrestrial with the aquatic environment. Size....... Altogether, DOM in agricultural headwaters is mainly complex-soil-derived and aromatic material with a low C:N ratio, which is more microbial processed than its counterpart from forest reference catchments. Our results emphasize the importance of agricultural land use on DOM loss from soils and identify......-exclusion chromatography, in combination with absorbance and emission matrix fluorometry, was applied to assess how agricultural land use alters the amount and composition of DOM, as well as dissolved organic nitrogen (DON) forms in headwater streams, including temporal variations, in a temperate region of NE Germany. By...

  7. Nitrous oxide emissions from rape field as affected by nitrogen fertilizer management: A case study in Central China

    Science.gov (United States)

    Lin, Shan; Iqbal, Javed; Hu, Ronggui; Wu, Jinshui; Zhao, Jinsong; Ruan, Leilei; Malghani, Saadatullah

    2011-03-01

    Agricultural soils are one of the major sources of atmospheric nitrous oxide (N 2O) emission. Red soil, one of the typical agricultural soils in sub-tropical China, plays an important role in the global N 2O flux emissions. To determine its N mineralization potential, a field study was conducted to assess the effect of application of nitrogen (N) fertilizer in a rape field under red soil at the experimental station of Heshengqiao at Xianning, Hubei, China. To estimate N-induced N 2O flux, we examined N 2O flux during the growth stages of the rape field including four treatments: fertilizer PK (N0), fertilizer NPK (60 kg N ha -1) (N1), fertilizer NPK (120 kg N ha -1) (N2), fertilizer NPK (240 kg N ha -1) (N3). There were distinct variations in soil N 2O fluxes (from 0.16 to 0.90 kg N ha -1), with higher values being observed during the spring and autumn while low values were observed during winter season. Among different treatments, N fertilization significantly increased the N 2O fluxes, with highest fluxes from N3 while lowest values being observed from N0 treatment. This suggested increased microbial activity in response to increased N fertilizer application. It was interesting to note that fertilizer-induced emissions decreased as the applied fertilizer amount was increased. During the whole growing season, N 2O flux did not correlate with soil temperature, but it significantly correlated to other environmental variables; water-filled pore space (WFPS), soil NO 3--N and NH 4+-N contents, which suggests the need for efficient water use and low inorganic nitrogen fertilizer management practices.

  8. Nitrogen leaching and acidification during 19 years of NH4NO3 additions to a coniferous-forested catchment at Gardsjoen, Sweden (NITREX)

    International Nuclear Information System (INIS)

    The role of nitrogen (N) in acidification of soil and water has become relatively more important as the deposition of sulphur has decreased. Starting in 1991, we have conducted a whole-catchment experiment with N addition at Gardsjoen, Sweden, to investigate the risk of N saturation. We have added 41 kg N ha-1 yr-1 as NH4NO3 to the ambient 9 kg N ha-1 yr-1 in fortnightly doses by means of sprinkling system. The fraction of input N lost to runoff has increased from 0% to 10%. Increased concentrations of NO3 in runoff partially offset the decreasing concentrations of SO4 and slowed ecosystem recovery from acid deposition. From 1990-2002, about 5% of the total N input went to runoff, 44% to biomass, and the remaining 51% to soil. The soil N pool increased by 5%. N deposition enhanced carbon (C) sequestration at a mean C/N ratio of 42-59 g g-1. - Research highlights: → The fraction of input N lost to runoff has increased from 0% to 10%. → Increased concentrations of NO3 in runoff slowed ecosystem recovery from acid deposition. → About 5% of the total N input went to runoff, 44% to biomass, and the remaining 51% to soil. → N deposition enhanced carbon (C) sequestration at a mean C/N ratio of 42-59 g g-1. - N addition has led to increased flux of N and increased C sequestration at a forested catchment in Sweden; the NO3 released has partially offset recovery from acidification.

  9. Nitrogen and Phosphorus Loads in an Agricultural Watershed Affected by Poultry Litter Application and Wastewater Effluent, Northeastern Oklahoma and Northwestern Arkansas, 2002-2009

    Science.gov (United States)

    Esralew, R.; Tortorelli, R. L.

    2010-12-01

    The Eucha-Spavinaw Basin in Northeastern Oklahoma and Northwestern Arkansas is the source of water for Lake Eucha and Spavinaw Lake, which are part of the water supply for the city of Tulsa, Oklahoma. Lake Eucha and Spavinaw Lakes have experienced deteriorating water quality largely due to growth of algae, notably cyanobacteria, from the excess input of nutrients. As a result, the city of Tulsa has spent millions of dollars to eliminate taste and odor problems resulting from production of algal and bacterial byproducts. To evaluate changes in nutrient loading resulting from a reduction in land application of poultry litter, installation of best management practices, and reductions in the phosphorus concentrations in wastewater effluent, the U.S. Geological Survey investigated nitrogen and phosphorus concentrations from samples collected during baseflow and runoff and used regression models to estimate nitrogen and phosphorus loads, yields, and flow-weighted concentrations in two major tributaries to Lake Eucha, Spavinaw and Beaty Creeks, for the period 2002-2009. Estimated mean flow-weighted total unfiltered nitrogen and phosphorus concentrations in the basin were about 5 to 10 times greater than the 75th percentile of flow-weighted nutrient concentrations in other mostly undeveloped basins of the United States. Spavinaw and Beaty Creeks contributed an estimated mean annual total load of about 762,500 kilograms of nitrogen and 49,200 kilograms of phosphorus per year, 76 to 91 percent of which was transported to Lake Eucha by runoff. Thirty-four percent of the nitrogen load and 48 percent of the phosphorus load to Lake Eucha occurred during the year 2008 which was the wettest year on record for the Eucha-Spavinaw Basin. The results of this analysis indicate that although efforts were made to control nutrient loading, nutrient concentrations, especially phosphorus, were substantially augmented by non-point sources and that most loading occurs during runoff events

  10. Water properties and structure of pork sausages as affected by high-pressure processing and addition of carrot fibre

    DEFF Research Database (Denmark)

    Møller, Sandie Mejer; Grossi, Alberto Blak; Christensen, Mette;

    2011-01-01

    The effects of high-pressure processing (HPP) and addition of carrot fibre on pork sausages have been studied using NMR T(2) relaxometry and measurements of water-binding capacity (WBC) by centrifugation. Significant effects of temperature (raw, 40, 50, or 60°C), holding time (1s, 3, 6, or 9min......), and addition of carrot fibre on the distribution and mobility of water were found. However, the effect of carrot fibre could not be explained by structural changes in the sausages when examined by confocal laser scanning microscopy (CLSM). Correlations between T(2) relaxation measurements and WBC...

  11. Tn5-induced mutants of Azotobacter vinelandii affected in nitrogen fixation under Mo-deficient and Mo-sufficient conditions.

    OpenAIRE

    Joerger, R D; Premakumar, R; Bishop, P E

    1986-01-01

    Mutants of Azotobacter vinelandii affected in N2 fixation in the presence of 1 microM Na2MoO4 (conventional system), 50 nM V2O5, or under Mo deficiency (alternative system) have been isolated after Tn5 mutagenesis with the suicide plasmid pSUP1011. These mutants can be grouped into at least four broad phenotypic classes. Mutants in the first class are Nif- under Mo sufficiency but Nif+ under Mo deficiency or in the presence of V2O5. A nifk mutant and a mutant apparently affected in regulation...

  12. Inclusion of sainfoin (Onobrychis viciifolia) silage in dairy cow rations affects nutrient digestibility, nitrogen utilization, energy balance, and methane emissions.

    Science.gov (United States)

    Huyen, N T; Desrues, O; Alferink, S J J; Zandstra, T; Verstegen, M W A; Hendriks, W H; Pellikaan, W F

    2016-05-01

    Sainfoin (Onobrychis viciifolia) is a tanniniferous legume forage that has potential nutritional and health benefits preventing bloating, reducing nematode larval establishment, improving N utilization, and reducing greenhouse gas emissions. However, the use of sainfoin as a fodder crop in dairy cow rations in northwestern Europe is still relatively unknown. The objective of this study was to evaluate the effect of sainfoin silage on nutrient digestibility, animal performance, energy and N utilization, and CH4 production. Six rumen-cannulated, lactating dairy cows with a metabolic body weight (BW(0.75)) of 132.5±3.6kg were randomly assigned to either a control (CON) or a sainfoin (SAIN)-based diet over 2 experimental periods of 25 d each in a crossover design. The CON diet was a mixture of grass silage, corn silage, concentrate, and linseed. In the SAIN diet, 50% of grass silage dry matter (DM) of the CON diet was exchanged for sainfoin silage. The cows were adapted to 95% of ad libitum feed intake for a 21-d period before being housed in climate-controlled respiration chambers for 4 d, during which time feed intake, apparent total-tract digestibility, N and energy balance, and CH4 production was determined. Data were analyzed using a mixed model procedure. Total daily DM, organic matter, and neutral detergent fiber intake did not differ between the 2 diets. The apparent digestibility of DM, organic matter, neutral detergent fiber, and acid detergent fiber were, respectively, 5.7, 4.0, 15.7, and 14.8% lower for the SAIN diet. Methane production per kilogram of DM intake was lowest for the SAIN diet, CH4 production as a percentage of gross energy intake tended to be lower, and milk yield was greater for the SAIN diet. Nitrogen intake, N retention, and energy retained in body protein were greater for the SAIN than for the CON diet. Nitrogen retention as a percentage of N intake tended to be greater for the SAIN diet. These results suggest that inclusion of sainfoin

  13. Soil pH and earthworms affect herbage nitrogen recovery from solid cattle manure in production grassland

    NARCIS (Netherlands)

    Rashid, M.I.; Goede, de R.G.M.; Corral Nunez, G.A.; Brussaard, L.; Lantinga, E.A.

    2014-01-01

    Long term use of inorganic fertilisers and reduced organic matter inputs have contributed to acidification of agricultural soils. This strongly affects the soil dwelling fauna and nutrient mineralisation. Organic fertilisers such as solid cattle manure (SCM) resurge as an option to overcome this aci

  14. Feed ingredients differing in fermentable fibre and indigestible protein content affect fermentation metabolites and faecal nitrogen excretion in growing pigs.

    Science.gov (United States)

    Jha, R; Leterme, P

    2012-04-01

    To study the fermentation characteristics of different non-conventional dietary fibre (DF) sources with varying levels of indigestible CP content and their effects on the production of fermentation metabolites and on faecal nitrogen (N) excretion, an experiment was conducted with 40 growing pigs (initial BW 23 kg) using wheat bran (WB), pea hulls (PH), pea inner fibres (PIF), sugar beet pulp (SBP) or corn distillers dried grains with solubles (DDGS). The diets also contained soya protein isolate, pea starch and sucrose, and were supplemented with vitamin-mineral premix. Faecal samples were collected for 3 consecutive days from day 10, fed with added indigestible marker (chromic oxide) for 3 days from day 13 and pigs were slaughtered on day 16 from the beginning of the experiment. Digesta from the ileum and colon were collected and analysed for short-chain fatty acids (SCFA) and ammonia (NH3) content. The apparent total tract N digestibility was the lowest (P pea fibres and SBP increased SCFA and reduced NH3 concentration in the pig's intestine and reduced faecal N excretion, which makes pea fibres and SBP an interesting ingredient to use in pig diet to improve the positive effect of DF fermentation on the gastrointestinal tract and reduce faecal N excretion. PMID:22436276

  15. Ultraviolet-B Radiation and Nitrogen Affect Nutrient Concentrations and the Amount of Nutrients Acquired by Above-Ground Organs of Maize

    Directory of Open Access Journals (Sweden)

    Carlos M. Correia

    2012-01-01

    Full Text Available UV-B radiation effects on nutrient concentrations in above-ground organs of maize were investigated at silking and maturity at different levels of applied nitrogen under field conditions. The experiment simulated a 20% stratospheric ozone depletion over Portugal. At silking, UV-B increased N, K, Ca, and Zn concentrations, whereas at maturity Ca, Mg, Zn, and Cu increased and N, P and Mn decreased in some plant organs. Generally, at maturity, N, Ca, Cu, and Mn were lower, while P, K, and Zn concentrations in stems and nitrogen-use efficiency (NUE were higher in N-starved plants. UV-B and N effects on shoot dry biomass were more pronounced than on nutrient concentrations. Nutrient uptake decreased under high UV-B and increased with increasing N application, mainly at maturity harvest. Significant interactions UV-B x N were observed for NUE and for concentration and mass of some elements. For instance, under enhanced UV-B, N, Cu, Zn, and Mn concentrations decreased in leaves, except on N-stressed plants, whereas they were less affected by N nutrition. In order to minimize nutritional, economical, and environmental negative consequences, fertiliser recommendations based on element concentration or yield goals may need to be adjusted.

  16. 20 CFR 655.737 - What are “exempt” H-1B nonimmigrants, and how does their employment affect the additional...

    Science.gov (United States)

    2010-04-01

    .... academic degree cannot be established through experience or through demonstration of expertise in the... does their employment affect the additional attestation obligations of H-1B-dependent employers and willful violator employers? 655.737 Section 655.737 Employees' Benefits EMPLOYMENT AND...

  17. Dry matter and nitrogen accumulation are not affected by superoptimal concentration of ammonium in flowing solution culture with pH control

    Science.gov (United States)

    Rideout, J. W.; Raper, C. D. Jr; Raper CD, J. r. (Principal Investigator)

    1994-01-01

    While it is known that superoptimal concentrations of the nitrate (NO3-) ion in solution culture do not increase NO3- uptake or dry matter accumulation, the same is not known for the ammonium (NH4+) ion. An experiment was conducted utilizing flowing solution culture with pH control to investigate the influence of superoptimal NH4+ concentrations on dry matter, nitrogen (N), potassium (K), calcium (Ca), and magnesium (Mg) accumulation by nonnodulated soybean plants. Increasing the NH4+ concentration in solution from 1 to 10 mM did not affect dry matter or N accumulation. Accumulations of K, Ca, and Mg were slightly decreased with increased NH4+ concentration. The NH4+ uptake system, which is saturated at less than 1mM NH4+, is able to regulate uptake of NH4+ at concentrations as high as 10 mM.

  18. Precursors and factors affecting formation of haloacetonitriles and chloropicrin during chlor(am)ination of nitrogenous organic compounds in drinking water.

    Science.gov (United States)

    Jia, Aiyin; Wu, Chunde; Duan, Yan

    2016-05-01

    This study investigated the precursors and factors affecting formation of haloacetonitriles (HANs) and chloropicrin (TCNM) during chlorination/chloramination of eight amino acids in the effluent water of V-type clarifying filtration from a drinking water treatment plant. The yields of trichloroacetonitrile (TCAN), dichloroacetonitrile (DCAN) and TCNM were higher during chlorination than during chloramination. Tyrosine and tryptophan produced the greatest amount of DCAN and also generated a small amount of TCAN during chlorination process. Besides, the yields of DCAN were higher than TCNM during chlorination/chloramination. Contact time, Cl2:org-N molar ratios, pH, temperature and bromide ion affected nitrogenous disinfection by-products (N-DBPs) formation during chlorination of tryptophan in different degrees. TCAN, DCAN and TCNM formation showed the increasing and then decreasing with prolonged contact time. Higher Cl2:org-N molar ratios improved N-DBPs formation within a certain range. The pH affected N-DBPs formation differently. HANs increased with increasing pH from 5 to 6 and decreased with increasing pH from 6 to 9, while TCNM increased with increasing pH from 5 to 9. Higher temperatures enhanced TCNM formation, but reduced the formation of TCAN and DCAN. The presence of bromide ions improved the yields of HANs and TCNM and shifted N-DBPs to more brominated ones. PMID:26859617

  19. Microbiological and biochemical characteristics of ground beef as affected by gamma irradiation, food additives and edible coating film

    Science.gov (United States)

    Ouattara, B.; Giroux, M.; Yefsah, R.; Smoragiewicz, W.; Saucier, L.; Borsa, J.; Lacroix, M.

    2002-03-01

    The current interest in "minimally processed foods" has attracted the attention for combination of mild treatments to improve food safety and shelf-life extention. The present study was conducted to evaluate the combined effect of gamma irradiation and incorporation of naturally occurring antimicrobial compounds on microbial and biochemistry characteristics of ground beef. Ground beef patties (23% fat ) were purchased from a local grocery store (IGA, Laval, Que., Canada) and divided into 3 separate treatment groups: (i) control (ground beef without additive), (ii) ground beef with 0.5% (w/w) ascorbic acid, and (iii) ground beef with 0.5% ascorbic acid and coated with a protein-based coating containing selected spices. Samples were irradiated at 0, 1, 2, and 3 kGy final dose at the CIC. Samples were stored at 4°C and evaluated periodically for microbial growth, total thiobarbituric reactive substances (TBARS) and free sulfydryl content. At the end of the storage period, Enterobacteriaceae, Lactic acid bacteria, Pseudomonas and Brochothrix thermosphacta were enumerated. Regardless of the treatment group, irradiation significantly ( p⩽0.05) reduced the total aerobic plate counts (APC). Irradiation doses of 1, 2, and 3 kGy produced immediate reduction of 2, 3, and 4 log units of APCs, respectively. Also, shelf-life periods were higher for ground beef samples containing food additives. Lactic acid bacteria and Brochothrix thermosphacta were more resistant to irradiation than Enterobacteriaceae and Pseudomonas. Concentration of TBARS and free sulfydryl concentrations were stabilized during post-irradiation storage for samples containing ascorbic acid and coated with the protein-based coating containing spices.

  20. Microbiological and biochemical characteristics of ground beef as affected by gamma irradiation, food additives and edible coating film

    International Nuclear Information System (INIS)

    The current interest in 'minimally processed foods' has attracted the attention for combination of mild treatments to improve food safety and shelf-life extension. The present study was conducted to evaluate the combined effect of gamma irradiation and incorporation of naturally occurring antimicrobial compounds on microbial and biochemistry characteristics of ground beef. Ground beef patties (23% fat ) were purchased from a local grocery store (IGA, Laval, Que., Canada) and divided into 3 separate treatment groups: (i) control (ground beef without additive), (ii) ground beef with 0.5% (w/w) ascorbic acid, and (iii) ground beef with 0.5% ascorbic acid and coated with a protein-based coating containing selected spices. Samples were irradiated at 0, 1, 2, and 3 kGy final dose at the CIC. Samples were stored at 4 deg. C and evaluated periodically for microbial growth, total thiobarbituric reactive substances (TBARS) and free sulfydryl content. At the end of the storage period, Enterobacteriaceae, Lactic acid bacteria, Pseudomonas and Brochothrix thermosphacta were enumerated. Regardless of the treatment group, irradiation significantly (p≤0.05) reduced the total aerobic plate counts (APC). Irradiation doses of 1, 2, and 3 kGy produced immediate reduction of 2, 3, and 4 log units of APCs, respectively. Also, shelf-life periods were higher for ground beef samples containing food additives. Lactic acid bacteria and Brochothrix thermosphacta were more resistant to irradiation than Enterobacteriaceae and Pseudomonas. Concentration of TBARS and free sulfydryl concentrations were stabilized during post-irradiation storage for samples containing ascorbic acid and coated with the protein-based coating containing spices

  1. Microbiological and biochemical characteristics of ground beef as affected by gamma irradiation, food additives and edible coating film

    Energy Technology Data Exchange (ETDEWEB)

    Ouattara, B.; Giroux, M.; Yefsah, R.; Smoragiewicz, W.; Saucier, L.; Borsa, J.; Lacroix, M. E-mail: monique.lacroix@inrs-iaf.uquebec.ca

    2002-03-01

    The current interest in 'minimally processed foods' has attracted the attention for combination of mild treatments to improve food safety and shelf-life extension. The present study was conducted to evaluate the combined effect of gamma irradiation and incorporation of naturally occurring antimicrobial compounds on microbial and biochemistry characteristics of ground beef. Ground beef patties (23% fat ) were purchased from a local grocery store (IGA, Laval, Que., Canada) and divided into 3 separate treatment groups: (i) control (ground beef without additive), (ii) ground beef with 0.5% (w/w) ascorbic acid, and (iii) ground beef with 0.5% ascorbic acid and coated with a protein-based coating containing selected spices. Samples were irradiated at 0, 1, 2, and 3 kGy final dose at the CIC. Samples were stored at 4 deg. C and evaluated periodically for microbial growth, total thiobarbituric reactive substances (TBARS) and free sulfydryl content. At the end of the storage period, Enterobacteriaceae, Lactic acid bacteria, Pseudomonas and Brochothrix thermosphacta were enumerated. Regardless of the treatment group, irradiation significantly (p{<=}0.05) reduced the total aerobic plate counts (APC). Irradiation doses of 1, 2, and 3 kGy produced immediate reduction of 2, 3, and 4 log units of APCs, respectively. Also, shelf-life periods were higher for ground beef samples containing food additives. Lactic acid bacteria and Brochothrix thermosphacta were more resistant to irradiation than Enterobacteriaceae and Pseudomonas. Concentration of TBARS and free sulfydryl concentrations were stabilized during post-irradiation storage for samples containing ascorbic acid and coated with the protein-based coating containing spices.

  2. EFFECTS OF PROTEIN-XANTHOPHYLL (PX CONCENTRATE OF ALFALFA ADDITIVE TO CRUDE PROTEIN-REDUCED DIETS ON NITROGEN EXCRETION, GROWTH PERFORMANCE AND MEAT QUALITY OF PIGS

    Directory of Open Access Journals (Sweden)

    Eugeniusz GRELA

    2009-06-01

    Full Text Available The infl uence of protein-xanthophyll (PX concentrate of alfalfa supplement to crude protein-reduced diets was examined in relation to nitrogen excretion, performance parameters and pig meat quality. The investigations included 60 growers (PL x PLW x Duroc crossbreeds assigned to 3 groups. The conclusion is that there is a large potential to decrease nitrogen emission to the environment by 10% lowering of dietary crude protein intake along with reduced animal growth rate and elevated mixture utilization. Inclusion of a protein-xanthophyll concentrate (PX of alfalfa to the diet is likely to diminish disadvantageous productive parameters arising from limiting of total crude protein level in relation to the requirements of pigs feeding norms [1993]. At the same time, it improves feed nitrogen utilization and reduces noxious odour emissions from a piggery. The components of a protein-xanthophyll concentrate (PX contribute to increased liver and kidney weight.

  3. Addition of Phenylboronic Acid to Malus domestica Pollen Tubes Alters Calcium Dynamics, Disrupts Actin Filaments and Affects Cell Wall Architecture

    Science.gov (United States)

    Fang, Kefeng; Gao, Sai; Zhang, Weiwei; Xing, Yu; Cao, Qingqin; Qin, Ling

    2016-01-01

    A key role of boron in plants is to cross-link the cell wall pectic polysaccharide rhamnogalacturonan-II (RG-II) through borate diester linkages. Phenylboronic acid (PBA) can form the same reversible ester bonds but cannot cross-link two molecules, so can be used as an antagonist to study the function of boron. This study aimed to evaluate the effect of PBA on apple (Malus domestica) pollen tube growth and the underlying regulatory mechanism. We observed that PBA caused an inhibition of pollen germination, tube growth and led to pollen tube morphological abnormalities. Fluorescent labeling, coupled with a scanning ion-selective electrode technique, revealed that PBA induced an increase in extracellular Ca2+ influx, thereby elevating the cytosolic Ca2+ concentration [Ca2+]c and disrupting the [Ca2+]c gradient, which is critical for pollen tube growth. Moreover the organization of actin filaments was severely perturbed by the PBA treatment. Immunolocalization studies and fluorescent labeling, together with Fourier-transform infrared analysis (FTIR) suggested that PBA caused an increase in the abundance of callose, de-esterified pectins and arabinogalactan proteins (AGPs) at the tip. However, it had no effect on the deposition of the wall polymers cellulose. These effects are similar to those of boron deficiency in roots and other organs, indicating that PBA can induce boron deficiency symptoms. The results provide new insights into the roles of boron in pollen tube development, which likely include regulating [Ca2+]c and the formation of the actin cytoskeleton, in addition to the synthesis and assembly of cell wall components. PMID:26886907

  4. Chronic nitrogen addition causes a reduction in soil carbon dioxide efflux during the high stem-growth period in a tropical montane forest but no response from a tropical lowland forest in decadal scale

    Directory of Open Access Journals (Sweden)

    B. Koehler

    2009-09-01

    Full Text Available Atmospheric nitrogen (N deposition is rapidly increasing in tropical regions. We studied the response of soil carbon dioxide CO2 efflux to long-term experimental N-addition (125 kg N ha−1 yr-1 in mature lowland and montane forests in Panamá. In the lowland forest, on soils with high nutrient-supplying and buffering capacity, fine litterfall and stem-growth were neither N- nor phosphorus-limited. In the montane forest, on soils with low nutrient supplying capacity and an organic layer, fine litterfall and stem-growth were N-limited. Our objectives were to 1 explore the influence of soil temperature and moisture on the dynamics of soil CO2 efflux and 2 determine the responses of soil CO2 efflux from an N-rich and N-limited forest to elevated N input. Annual soil CO2-C efflux was larger from the lowland (15.20±1.25 Mg C ha−1 than the montane forest (9.36±0.29 Mg C ha−1. In the lowland forest, soil moisture explained the largest fraction of the variance in soil CO2 efflux while soil temperature was the main explanatory variable in the montane forest. Soil CO2 efflux in the lowland forest did not differ between the control and 9–11 yr N-addition plots, suggesting that chronic N input to nutrient-rich tropical lowland forests on well-buffered soils may not change their C balance in decadal scale. In the montane forest, first year N addition did not affect soil CO2 efflux but annual CO2 efflux was reduced by 14% and 8% in the 2- and 3 yr N-addition plots, respectively, compared to the control. This reduction was caused by a decrease in soil CO2 efflux during the high stem-growth period of the year, suggesting a shift in carbon partitioning from below- to aboveground in the N-addition plots where stem diameter growth was promoted.

  5. Chronic nitrogen addition causes a reduction in soil carbon dioxide efflux during the high stem-growth period in a tropical montane forest but no response from a tropical lowland forest on a decadal time scale

    Directory of Open Access Journals (Sweden)

    B. Koehler

    2009-12-01

    Full Text Available Atmospheric nitrogen (N deposition is rapidly increasing in tropical regions. We studied the response of soil carbon dioxide (CO2 efflux to long-term experimental N addition (125 kg N ha−1 yr−1 in mature lowland and montane forests in Panama. In the lowland forest, on soils with high nutrient-supplying and buffering capacity, fine litterfall and stem-growth were neither N- nor phosphorus-limited. In the montane forest, on soils with low nutrient supplying capacity and an organic layer, fine litterfall and stem-growth were N-limited. Our objectives were to 1 explore the influence of soil temperature and moisture on the dynamics of soil CO2 efflux and 2 determine the responses of soil CO2 efflux from an N-rich and N-limited forest to elevated N input. Annual soil CO2-C efflux was larger in the lowland (15.44 ± 1.02 Mg C ha−1 than in the montane forest (9.37 ± 0.28 Mg C ha−1. In the lowland forest, soil moisture explained the largest fraction of the variance in soil CO2 efflux while soil temperature was the main explanatory variable in the montane forest. Soil CO2 efflux in the lowland forest did not differ between the control and 9–11 yr N-addition plots, suggesting that chronic N input to nutrient-rich tropical lowland forests on well-buffered soils may not change their C balance on a decadal time scale. In the montane forest, first year N addition did not affect soil CO2 efflux but annual CO2 efflux was reduced by 14% and 8% in the 2nd and 3rd year N-addition plots, respectively, compared to the control. This reduction was caused by a decrease in soil CO2 efflux during the high stem-growth period of the year, suggesting a shift in carbon partitioning from below- to aboveground in the N-addition plots in which stem diameter growth was promoted.

  6. Tn5-induced mutants of Azotobacter vinelandii affected in nitrogen fixation under Mo-deficient and Mo-sufficient conditions

    Energy Technology Data Exchange (ETDEWEB)

    Joerger, R.D.; Premakumar, R.; Bishop, P.E.

    1986-11-01

    Mutants of Azotobacter vinelandii affected in N/sub 2/ fixation in the presence of 1 ..mu..M Na/sub 2/MoO/sub 4/ (conventional system), 50 nM V/sub 2/O/sub 5/, or under Mo deficiency (alternative system) have been isolated after Tn5 mutagenesis with the suicide plasmid pSUP1011. These mutants are grouped into four broad phenotypic classes. Mutants in the first class are Nif/sup -/ under Mo sufficiency but Nif/sup +/ under Mo deficiency or in the presence of V/sub 2/O/sub 5/. Mutants in the second class are Nif/sup -/ under all conditions. An FeMo-cofactor-negative mutant (NifB/sup -/) belongs to this class. The third mutant class consists of mutants incapable of N/sub 2/-dependent growth under Mo deficiency. Most of the mutants of this class are also affected in N/sub 2/ fixation in the presence of 1 ..mu..M Na/sub 2/MoO/sub 4/, with acetylene reduction rates ranging from 28 to 51% of the rates of the wild type. Strains constructed by genetic transfer of the Kan/sup r/ marker of mutants from this class into nifHDK or nifK deletion mutants showed N/sub 2/-dependent growth only in the presence of V/sup 2/O/sub 5/. The only mutant in the fourth class shows wild-type nitrogenase activity under Mo sufficiency, but only 10% of the acetylene reduction activity of the wild type in the presence of 50 nM V/sub 2/O/sub 5/. The acetylene reduction rates of whole cells of this mutant are identical in Mo-deficient medium and in medium containing V/sub 2/O/sub 5/. The conventional nitrogenase subunits are expressed in this mutant even under Mo deficiency or in the presence of V/sub 2/O/sub 5/; however, the NH/sub 4//sup +/-and Mo-repressible proteins normally seen under these conditions could not be detected on two-dimensional gels.

  7. Soil nitrogen cycling and nitrous oxide flux in a Rocky Mountain Douglas-fir forest - Effects of fertilization, irrigation and carbon addition

    Science.gov (United States)

    Matson, Pamela A.; Gower, Stith T.; Volkmann, Carol; Billow, Christine; Grier, Charles C.

    1992-01-01

    Nitrous oxide fluxes and soil nitrogen transformations were measured in experimentally-treated high elevation Douglas-fir forests in northwestern New Mexico, USA. On an annual basis, forests that were fertilized with 200 kg N/ha emitted an average of 0.66 kg/ha of N2O-N, with highest fluxes occurring in July and August when soils were both warm and wet. Control, irrigated, and woodchip treated plots did not differ, and annual average fluxes ranged from 0.03 to 0.23 kg/ha. Annual net nitrogen mineralization and nitrate production were estimated in soil and forest floor using in situ incubations; fertilized soil mineralized 277 kg/ha/y in contrast to 18 kg/ha/y in control plots. Relative recovery of 15NH4-N applied to soil in laboratory incubations was principally in the form of NO3-N in the fertilized soils, while recovery was mostly in microbial biomass-N in the other treatments. Fertilization apparently added nitrogen that exceeded the heterotrophic microbial demand, resulting in higher rates of nitrate production and higher nitrous oxide fluxes. Despite the elevated nitrous oxide emission resulting from fertilization, we estimate that global inputs of nitrogen into forests are not currently contributing significantly to the increasing concentrations of nitrous oxide in the atmosphere.

  8. A adição de superfosfato triplo e a percolação de nitrogênio no solo Addition of triple superphosphate anticipates nitrogen leaching in soil

    Directory of Open Access Journals (Sweden)

    Analu Mantovani

    2007-10-01

    ção de Ca.Leaching of N added to soils as ammonium or as other forms that transform into it depends partially on nitrification because ammonium is retained by the soil negative charges, while nitrate remains completely in the soil solution. Since the decrease of the soil pH at fertilized sites can negatively affect nitrification, our study aimed to evaluate the effect of adding an acidifying phosphate together with nitrogen fertilizers on nitrogen leaching in an acid soil. The experiment was carried out in 2003, in an Alfisol with clay and organic matter contents of 760 and 40 g kg-1, respectively and pH (H2O of 4.8. Treatments consisted of three nitrogen sources (urea, ammonium sulfate and calcium nitrate at rates of 150 mg kg-1 of N plus one control treatment without N in factorial combination with triple superphosphate (TSP at a rate of 751 mg kg-1. Treated experimental soil units were packed into PVC leaching columns and percolated with 300 mL of distilled water every seven days, during 19 weeks, totalizing an amount equivalent to 720 mm of rain. TSP addition anticipated ammonium leaching due to displacement of ammonium from the soil negative charges by added calcium. Nitrate leaching from the soil treated with calcium nitrate occurred in the first percolations regardless of TSP addition. In soils treated with the other two N fertilizers, nitrate leaching was intensified only after the seventh percolation, but it was anticipated to the fifth percolation by TSP addition due to earlier nitrification caused by displacement of exchangeable ammonium to the soil solution. TSP addition doubled nitrate leaching in the urea treated soil, while leaching decreased by about 20 % when TSP was mixed with ammonium sulfate or calcium nitrate. In the absence of TSP, 70 % of the N added via urea remained in the soil after the end of the percolations, but in the presence of TSP all applied N was lost. Overall, TSP combined with ammonium or amide-containing nitrogen fertilizers

  9. DRD2 and PPP1R1B (DARPP-32 polymorphisms independently confer increased risk for autism spectrum disorders and additively predict affected status in male-only affected sib-pair families

    Directory of Open Access Journals (Sweden)

    Hettinger Joe A

    2012-05-01

    Full Text Available Abstract Background The neurotransmitter dopamine (DA modulates executive functions, learning, and emotional processing, all of which are impaired in individuals with autism spectrum disorders (ASDs. Our previous findings suggest a role for dopamine-related genes in families with only affected males. Methods We examined two additional genes which affect DA function, the DRD2 and PPP1R1B (DARPP-32 genes, in a cohort of 112 male-only affected sib-pair families. Selected polymorphisms spanning these genes were genotyped and both family-based and population-based tests were carried out for association analysis. General discriminant analysis was used to examine the gene-gene interactions in predicting autism susceptibility. Results There was a significantly increased frequency of the DRD2 rs1800498TT genotype (P = 0.007 in affected males compared to the comparison group, apparently due to over-transmission of the T allele (P = 0.0003. The frequency of the PPP1R1B rs1495099CC genotype in affected males was also higher than that in the comparison group (P = 0.002 due to preferential transmission of the C allele from parents to affected children (P = 0.0009. Alleles rs1800498T and rs1495099C were associated with more severe problems in social interaction (P = 0.0002 and P = 0.0016, respectively and communication (P = 0.0004 and P = 0.0046, and increased stereotypic behaviours (P = 0.0021 and P = 0.00072. General discriminant analysis found that the DRD2 and PPP1R1B genes additively predicted ASDs (P = 0.00011; Canonical R = 0.26 and explain ~7% of the variance in our families. All findings remained significant following corrections for multiple testing. Conclusion Our findings support a role for the DRD2 and PPP1R1B genes in conferring risk for autism in families with only affected males and show an additive effect of these genes towards prediction of affected status in our families.

  10. Comparison of point injection and top-dressing application of nitrogen fertilizers with sulphur addition in winter rape (Brassica napus L.) in the Czech Republic

    OpenAIRE

    Lucie Peklová; Jindřich Černý; Zuzana Peklová; Karin Kubešová; Ondřej Sedlář; Jiří Balík

    2015-01-01

    In this paper, we are analyzing the yield and yield parameters of winter rape, fertilized using CULTAN system (Controlled Uptake Long Term Ammonium Nutrition) in comparison with top-dressing application of nitrogen fertilizers, which were studied on Haplic Luvisol over 5 years. No significant differences in seed yields between the two systems of fertilization were observed in 2008, 2009 and 2011. The effect of sulphur on a higher seed yield was proved in 2010 and 2012. The seed yield was high...

  11. Nitrogen starvation affects bacterial adhesion to soil Adesão de bactérias desnutridas por nitrogênio a solo

    Directory of Open Access Journals (Sweden)

    Maria Tereza Borges

    2008-09-01

    Full Text Available One of the main factors limiting the bioremediation of subsoil environments based on bioaugmentation is the transport of selected microorganisms to the contaminated zones. The characterization of the physiological responses of the inoculated microorganisms to starvation, especially the evaluation of characteristics that affect the adhesion of the cells to soil particles, is fundamental to anticipate the success or failure of bioaugmentation. The objective of this study was to investigate the effect of nitrogen starvation on cell surface hydrophobicity and cell adhesion to soil particles by bacterial strains previously characterized as able to use benzene, toluene or xilenes as carbon and energy sources. The strains LBBMA 18-T (non-identified, Arthrobacter aurescens LBBMA 98, Arthrobacter oxydans LBBMA 201, and Klebsiella sp. LBBMA 204-1 were used in the experiments. Cultivation of the cells in nitrogen-deficient medium caused a significant reduction of the adhesion to soil particles by all the four strains. Nitrogen starvation also reduced significantly the strength of cell adhesion to the soil particles, except for Klebsiella sp. LBBMA 204-1. Two of the four strains showed significant reduction in cell surface hydrophobicity. It is inferred that the efficiency of bacterial transport through soils might be potentially increased by nitrogen starvation.Um dos principais fatores limitantes da biorremediação in situ de solos subterrâneos, baseada na bioaumentação, é o transporte dos microrganismos selecionados até o local contaminado. A caracterização das respostas fisiológicas dos microrganismos introduzidos no subsolo a condições de escassez nutricional, notadamente a avaliação de características que afetam a adesão celular ao solo, é fundamental para se prever o sucesso da bioaumentação. O objetivo deste trabalho foi determinar o efeito da desnutrição em meio com escassez de nitrogênio sobre a hidrofobicidade celular e a

  12. Chronic nitrogen addition causes a reduction in soil carbon dioxide efflux during the high stem-growth period in a tropical montane forest but no response from a tropical lowland forest on a decadal time scale

    OpenAIRE

    B. Koehler; M. D. Corre; Veldkamp, E.; Sueta, J. P.

    2009-01-01

    Atmospheric nitrogen (N) deposition is rapidly increasing in tropical regions. We studied the response of soil carbon dioxide (CO2) efflux to long-term experimental N addition (125 kg N ha−1 yr−1) in mature lowland and montane forests in Panama. In the lowland forest, on soils with high nutrient-supplying and buffering capacity, fine litterfall and stem-growth were neither N- nor phosphorus-limited. In th...

  13. Importance of within-lake processes in affecting the dynamics of dissolved organic carbon and dissolved organic and inorganic nitrogen in an Adirondack forested lake/watershed

    Directory of Open Access Journals (Sweden)

    P.-G. Kang

    2015-10-01

    Full Text Available Lakes nested in forested watersheds play important roles in mediating the concentrations and fluxes of dissolved organic matter. We compared long-term patterns of concentrations and fluxes of dissolved organic carbon (DOC, dissolved organic nitrogen (DON, and dissolved inorganic nitrogen (DIN in the Arbutus Lake Watershed to evaluate how a lake nested in a forested watershed affects the dynamics of DOC and DON in the Adirondack Mountains of New York State, USA. We observed no significant long-term changes of concentrations and fluxes of DOC and DON in the Lake outlet since 1983 and 1994, respectively. However, the temporal patterns of DOC and DON concentrations in the Lake inlet showed significant seasonality such as increases during the vegetation-growing season along with notable decreases in the dormant season. A comparison of mass-balances between inlet and outlet for the period from 2000 to 2009 suggested that the Lake was a sink of DOC (mean of influx minus outflux: +1140 mol C ha−1 yr−1. In contrast, the difference of discharge-weighted DON concentrations (mean of inlet minus outlet: −1.0 μmol N L−1 between inlet and outlet was much smaller than the discharge-weighted DOC concentrations (average of inlet minus outlet: +87 μmol C L−1. DON fluxes showed considerable variation among years (mean of influx minus outflux: +8 mol N ha−1 yr−1; range of differences: −15 to 27 mol N ha−1 yr−1. DON exhibited low % retention ((influx − outflux / influx (mean: 6.9 %, range: −34.8 to +31.2 compared to DOC (mean: 30.1 %, range: +9.2 to +44.1. The resultant increase of DON within the lake was closely linked with a net decrease of DIN through monthly Pearson correlation analysis, suggesting the importance of biotic factors in mediating a lake DON dynamics. Our results show different relative retentions of DOC compared with DON, along with a larger retention of DIN than DON, suggesting that DOC and DON might display substantially

  14. Importance of within-lake processes in affecting the dynamics of dissolved organic carbon and dissolved organic and inorganic nitrogen in an Adirondack forested lake/watershed

    Science.gov (United States)

    Kang, P.-G.; Mitchell, M. J.; McHale, P. J.; Driscoll, C. T.; McHale, M. R.; Inamdar, S.; Park, J.-H.

    2015-10-01

    Lakes nested in forested watersheds play important roles in mediating the concentrations and fluxes of dissolved organic matter. We compared long-term patterns of concentrations and fluxes of dissolved organic carbon (DOC), dissolved organic nitrogen (DON), and dissolved inorganic nitrogen (DIN) in the Arbutus Lake Watershed to evaluate how a lake nested in a forested watershed affects the dynamics of DOC and DON in the Adirondack Mountains of New York State, USA. We observed no significant long-term changes of concentrations and fluxes of DOC and DON in the Lake outlet since 1983 and 1994, respectively. However, the temporal patterns of DOC and DON concentrations in the Lake inlet showed significant seasonality such as increases during the vegetation-growing season along with notable decreases in the dormant season. A comparison of mass-balances between inlet and outlet for the period from 2000 to 2009 suggested that the Lake was a sink of DOC (mean of influx minus outflux: +1140 mol C ha-1 yr-1). In contrast, the difference of discharge-weighted DON concentrations (mean of inlet minus outlet: -1.0 μmol N L-1) between inlet and outlet was much smaller than the discharge-weighted DOC concentrations (average of inlet minus outlet: +87 μmol C L-1). DON fluxes showed considerable variation among years (mean of influx minus outflux: +8 mol N ha-1 yr-1; range of differences: -15 to 27 mol N ha-1 yr-1). DON exhibited low % retention ((influx - outflux) / influx) (mean: 6.9 %, range: -34.8 to +31.2) compared to DOC (mean: 30.1 %, range: +9.2 to +44.1). The resultant increase of DON within the lake was closely linked with a net decrease of DIN through monthly Pearson correlation analysis, suggesting the importance of biotic factors in mediating a lake DON dynamics. Our results show different relative retentions of DOC compared with DON, along with a larger retention of DIN than DON, suggesting that DOC and DON might display substantially different biogeochemical

  15. 落叶松原始林树木生长对氮添加的响应%Response of tree growth to nitrogen addition in a Larix gmelinii primitive forest

    Institute of Scientific and Technical Information of China (English)

    刘修元; 杜恩在; 徐龙超; 沈海花; 方精云; 胡会峰

    2015-01-01

    氮沉降对树木生长的影响是全球变化研究的一个核心问题。该文通过设置4种氮添加水平(对照(0)、低氮(20 kg N·hm–2·a–1)、中氮(50 kg N·hm–2·a–1)和高氮(100 kg N·hm–2·a–1)),研究了模拟氮沉降对落叶松(Larix gmelinii)原始林树木胸径生长的影响。结果表明:中氮和高氮添加对落叶松胸径相对生长率有显著影响,而且这种影响随施氮年限的增加而增强。不同高度的树木对氮添加的响应有很大差异,较低树木(树高16.5 m)的树木在中氮和高氮处理下胸径生长有显著加速(胸径相对生长率增幅>79.5%),但随着树木高度的进一步增加,这种加速作用明显下降。研究结果显示氮添加会促进落叶松胸径生长,这种促进作用主要发生在较高的落叶松个体中。%Aims Global nitrogen (N) deposition has been consistently enhanced and significantly influenced the carbon (C) cycle of forest ecosystem. However, studies on the quantitive response of C sequestration to N deposition in China’s boreal forest ecosystem still remains insufficient. Tree growth is one of important components of C sequestration in forest ecosystem. In order to accurately evaluate the influence of N deposition on C sequestration in China’s boreal forest ecosystem, This study was designed to investigate how N deposition influenced the tree diameter at breast height (DBH) growth of a Larix gmelinii primitive forest. Methods We carried out a N enrichment experiment in an L. gmelinii primitive forest in Greater Khingan Mountains with four N addition levels (control (0), low N (20 kg N·hm–2·a–1), medium N (50 kg N·hm–2·a–1) and high N (100 kg N·hm–2·a–1)). DBH was measured from 2012–2014 within all treatments. Important findings Medium N and high N additions significantly influenced the relative DBH growth of L. gmelinii, and the influence became more pronounced through time. N deposition significantly

  16. Amelioration of bauxite residue sand by intermittent additions of nitrogen fertiliser and leaching fractions: The effect on growth of kikuyu grass and fate of applied nutrients.

    Science.gov (United States)

    Kaur, Navjot; Phillips, Ian; Fey, Martin V

    2016-04-15

    Bauxite residue, a waste product of aluminium processing operations is characterised by high pH, salinity and exchangeable sodium which hinders sustainable plant growth. The aim of this study was to investigate the uptake form, optimum application rate and timing of nitrogen fertiliser to improve bauxite residue characteristics for plant growth. Kikuyu grass was grown in plastic columns filled with residue sand/carbonated residue mud mixture (20:1) previously amended with gypsum, phosphoric acid and basal nutrients. The experiment was set up as a 4×4 factorial design comprising four levels of applied nitrogen (N) fertiliser (0, 3, 6 and 12mgNkg(-1) residue) and four frequencies of leaching (16, 8 and 4day intervals). We hypothesised that the use of ammonium sulfate fertiliser would increase retention of N within the rhizosphere thereby encouraging more efficient fertiliser use. We found that N uptake by kikuyu grass was enhanced due to leaching of excess salts and alkalinity from the residue profile. It was also concluded that biomass production and associated N uptake by kikuyu grass grown in residue is dependent on the type of fertiliser used. PMID:26824271

  17. Cognitive and affective empathy in children with conduct problems: additive and interactive effects of callous-unemotional traits and autism spectrum disorders symptoms.

    Science.gov (United States)

    Pasalich, Dave S; Dadds, Mark R; Hawes, David J

    2014-11-30

    Callous-unemotional (CU) traits and autism spectrum disorders (ASD) symptoms are characterized by problems in empathy; however, these behavioral features are rarely examined together in children with conduct problems. This study investigated additive and interactive effects of CU traits and ASD symptoms in relation to cognitive and affective empathy in a non-ASD clinic-referred sample. Participants were 134 children aged 3 to 9 years (M=5.60; 79% boys) with oppositional defiant/conduct disorder, and their parents. Clinicians, teachers, and parents reported on dimensions of child behavior, and parental reports of family dysfunction and direct observations of parental warmth/responsiveness assessed quality of family relationships. Results from multiple regression analysis showed that, over and above the effects of child conduct problem severity and quality of family relationships, both ASD symptoms and CU traits were uniquely associated with deficits in cognitive empathy. Moreover, CU traits demonstrated an independent association with affective empathy, and this relationship was moderated by ASD symptoms. That is, there was a stronger negative association between CU traits and affective empathy at higher versus lower levels of ASD symptoms. These findings suggest including both CU traits and ASD-related social impairments in models delineating the atypical development of empathy in children with conduct problems. PMID:25015711

  18. Effects of nitrogen atoms of benzotriazole and its derivatives on the properties of electrodeposited Cu films

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hoe Chul; Kim, Myung Jun; Lim, Taeho; Park, Kyung Ju; Kim, Kwang Hwan; Choe, Seunghoe [School of Chemical and Biological Engineering, Institute of Chemical Process, Seoul National University, Gwanak 1, Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of); Kim, Soo-Kil, E-mail: sookilkim@cau.ac.kr [School of Integrative Engineering, Chung-Ang University, 221 Heukseok-dong, Dongjak-gu, Seoul 156-756 (Korea, Republic of); Kim, Jae Jeong, E-mail: jjkimm@snu.ac.kr [School of Chemical and Biological Engineering, Institute of Chemical Process, Seoul National University, Gwanak 1, Gwanak-ro, Gwanak-gu, Seoul 151-744 (Korea, Republic of)

    2014-01-01

    Additives having azole groups with different numbers of nitrogen atoms, such as indole, benzimidazole, indazole, benzotriazole (BTA), and 1H-benzotriazole-methanol (BTA-MeOH) were adopted to improve the mechanical hardness of electrodeposited Cu films. The effects of these additives on the film properties were elucidated in relation to their number of nitrogen atoms. Electrochemical current–potential behaviors showed that the additives containing three nitrogen atoms (BTA and BTA-MeOH) more effectively inhibited Cu electrodeposition. The inhibition strongly affected the film properties, resulting in reduced grain size and surface roughness, and increased resistivity and hardness. Cu films deposited with BTA or BTA-MeOH also exhibited 35% reduced grain size and 1.5-time higher hardness than Cu films deposited in electrolyte containing other BTA-derivatives having fewer nitrogen atoms. This notable grain refining effect of BTA and BTA-MeOH can be evaluated with respect to the strong interaction of their nitrogen atoms with the substrate and the copper ions, as well. - Highlights: • Additives of similar structure containing 1, 2, and 3 nitrogen atoms were used. • Additives with 3 nitrogen atoms more strongly inhibited Cu deposition than others. • Additives containing 3 nitrogen atoms efficiently affected film properties. • Additives having 3 nitrogen atoms remarkably improved film hardness.

  19. Roughage digestibility and velocity of its passage through the alimentary tract of wethers as affected by mineral additives and gamma irradiation

    International Nuclear Information System (INIS)

    Balance trials conducted with wethers established the apparent digestibility of roughage and the velocity of its passage through the alimentary tract. All rations amounted to 1000 g daily. Studied was the influence of 4% bentonit supplementation of the ration of ground meadow hay and of 7% bentonit to ration of 60%. ground lucerne hay and 40% concentrate. 4% bentonit supplementation did not affect the velocity of passage through the alimentary tract, but 7% bentonit supplementation depressed apparent digestibility. The addition of 12 g MgO and 5 NaHCO3 to a ration of 1000 g finely ground meadow hay was studied under the same conditions. There were no considerable changes in digestibility and velocity of passage. Acetic acid molar ratio was slightly enhanced. The influence of gamma irradiation on pellets of 85% meadow hay and 15% concentrate was studied also under the same conditions. The irradiation dose was 4 Mr. Crude fat digestibility went up and that of crude fiber - dropped. However, organic matter digestibility was not affected. These data resemble the results obtained with complete roughage ration mixtures following pelleting. (author)

  20. Chronic nitrogen addition causes a reduction in soil carbon dioxide efflux during the high stem-growth period in a tropical montane forest but no response from a tropical lowland forest in decadal scale

    OpenAIRE

    B. Koehler; M. D. Corre; Veldkamp, E.; Sueta, J. P.

    2009-01-01

    Atmospheric nitrogen (N) deposition is rapidly increasing in tropical regions. We studied the response of soil carbon dioxide CO2 efflux to long-term experimental N-addition (125 kg N ha−1 yr-1) in mature lowland and montane forests in Panamá. In the lowland forest, on soils with high nutrient-supplying and buffering capacity, fine litterfall and stem-growth were neither N- nor phosphorus-limited. In the montane fo...

  1. The Effect of Nitrogen Enrichment on C1-Cycling Microorganisms and Methane Flux in Salt Marsh Sediments

    OpenAIRE

    Irina Catherine Irvine; Lucía eVivanco; Peris N. Bentley; Martiny, Jennifer B. H.

    2012-01-01

    Methane (CH4) flux from ecosystems is driven by C1-cycling microorganisms – the methanogens and the methylotrophs. Little is understood about what regulates these communities, complicating predictions about how global change drivers such as nitrogen enrichment will affect methane cycling. Using a nitrogen addition gradient experiment in three Southern California salt marshes, we show that sediment CH4 flux increased linearly with increasing nitrogen addition (1.23 µg CH4 m-2 d-1 for each...

  2. Importance of within-lake processes in affecting the dynamics of dissolved organic carbon and dissolved organic and inorganic nitrogen in an Adirondack forested lake/watershed

    Science.gov (United States)

    Kang, Phil-Goo; Mitchell, Myron J.; McHale, Patrick J.; Driscoll, Charles T.; Inamdar, Shreeram; Park, Ji-Hyung

    2016-05-01

    Lakes nested in forested watersheds play an important role in mediating the concentrations and fluxes of dissolved organic matter. We compared long-term patterns of concentrations and fluxes of dissolved organic carbon (DOC) and dissolved organic (DON) and inorganic nitrogen (DIN) in aquatic ecosystems of the Arbutus Lake watershed to evaluate how a lake nested in a forested watershed affects the sources (e.g., production) and sinks (e.g., retention) of DOC and DON in the Adirondack Mountains of New York, USA. We observed no significant long-term changes of DOC and DON in the lake outlet since 1983 and 1994, respectively. However, the temporal patterns of DOC and DON concentrations in the lake inlet showed significant seasonality such as increases during the vegetation-growing season along with notable decreases in the dormant season. A comparison of mass balances between inlet and outlet for the period from 2000 to 2009 suggested that the lake was a sink of DOC (mean of influx minus outflux: +1140 mol C ha-1 yr-1). In contrast, the difference of discharge-weighted DON concentrations (mean of inlet minus outlet: -1.0 µmol N L-1) between inlet and outlet was much smaller than the discharge-weighted DOC concentrations (average of inlet minus outlet: + 87 µmol C L-1). DON fluxes showed considerable variation among years (mean of influx minus outflux: +8 mol N ha-1 yr-1; range of differences: -15 to 27 mol N ha-1 yr-1). DON exhibited low percent retention ((influx-outflux)/influx) (mean: 6.9 %, range: -34.8 to +31.2) compared to DOC (mean: 30.1 %, range: +9.2 to +44.1). The resultant increase of DON within the lake was closely linked with a net decrease of DIN through monthly Pearson correlation analysis, suggesting the importance of biotic factors in mediating lake DON dynamics. Our results show different relative retentions of DOC compared with DON, along with a larger retention of DIN than DON, suggesting that DOC and DON might display substantially different

  3. The Effect of Nitrogen Sources and Its Additional Strategies on L-valine Fermentation by Brevibacterium flavum XV0505%氮源及其补加策略对L-缬氨酸发酵的影响

    Institute of Scientific and Technical Information of China (English)

    冯宁; 白亚磊; 徐庆阳; 谢希贤; 陈宁

    2011-01-01

    通过分析黄色短杆菌xv0505发酵生产L-缬氨酸的过程,得知在菌体生长期和快速产酸期氮源对L-缬氨酸发酵的影响不同.以黄色短杆菌XV0505为供试菌株,研究了不同氮源种类及不同氮源浓度对L-缬氨酸发酵过程的影响,选定了以豆饼水解液和硫酸铵为氮源,并确定了合适的初始氮源浓度.在初始氮源浓度相同的情况下,考察了间歇流加补氮策略、恒氮源浓度补氮策略和幂函数流加补氮策略对L-缬氨酸发酵的影响,研究发现,幂指数补氮策略可减少频繁的取样及铵浓度检测,在缺乏在线监测系统和反馈自控系统的情况下,将发酵体系中氮源浓度维持在合适值,既可适度促进菌体生长,又可使L-缬氨酸的产量得到进一步提高.在最优的氮源添加策略下,在30 L发酵罐发酵60 h,发酵液中L-缬氨酸可达63.17 g/L,糖酸转化率24.69%.%By analyzing the L-valine fermentation process by Brevibacterium flavum XV0505, one of important factors influenced on the bacterial productivity and L-valine yield is nitrogen source and its additional strategies. The effect of nitrogen sources on the fermentation of L-valine was studied by adding different nitrogen sources with different concentrations. Therefore, soybean hydrolysates and ammonium sulfate were selected as the appropriate nitrogen source, and the best L-valine yield was obtained with the medium supplemented low initial concentration of 225 mmol/L. In the case of the same initial nitrogen concentration, the effects of three nitrogen feeding strategies (intermittent nitrogen feeding,constant concentration feeding and power function feeding) on biomass, yield of L-valine,concentration of byproduct and conversion rate were studied in the 30L fermentor. The result showed that the concentration and the feed rate of nitrogen source were effectively and timely manipulated by power function feeding, while lacking of online monitoring and feedback

  4. Effects of liquid aluminum chloride additions to poultry litter on broiler performance, ammonia emissions, soluble phosphorus, total volatile fatty acids, and nitrogen contents of litter

    Science.gov (United States)

    Recent studies have shown that the use of aluminum sulfate (Al2(SO4)3.14H2O) and aluminum chloride (AlCl3) additions to animal manures are more effective than other chemicals in reducing ammonia (NH3) emissions and phosphorus (P) solubility. Although the use of alum has been intensively used in the ...

  5. Differential responses of short-term soil respiration dynamics to the experimental addition of nitrogen and water in the temperate semi-arid steppe of Inner Mongolia, China.

    Science.gov (United States)

    Qi, Yuchun; Liu, Xinchao; Dong, Yunshe; Peng, Qin; He, Yating; Sun, Liangjie; Jia, Junqiang; Cao, Congcong

    2014-04-01

    We examined the effects of simulated rainfall and increasing N supply of different levels on CO2 pulse emission from typical Inner Mongolian steppe soil using the static opaque chamber technique, respectively in a dry June and a rainy August. The treatments included NH4NO3 additions at rates of 0, 5, 10, and 20 g N/(m(2)·year) with or without water. Immediately after the experimental simulated rainfall events, the CO2 effluxes in the watering plots without N addition (WCK) increased greatly and reached the maximum value at 2 hr. However, the efflux level reverted to the background level within 48 hr. The cumulative CO2 effluxes in the soil rang ed from 5.60 to 6.49 g C/m(2) over 48 hr after a single water application, thus showing an increase of approximately 148.64% and 48.36% in the effluxes during both observation periods. By contrast, the addition of different N levels without water addition did not result in a significant change in soil respiration in the short term. Two-way ANOVA showed that the effects of the interaction between water and N addition were insignificant in short-term soil CO2 effluxes in the soil. The cumulative soil CO2 fluxes of different treatments over 48 hr accounted for approximately 5.34% to 6.91% and 2.36% to 2.93% of annual C emission in both experimental periods. These results stress the need for improving the sampling frequency after rainfall in future studies to ensure more accurate evaluation of the grassland C emission contribution. PMID:25079414

  6. Dye stability and performances of dye-sensitized solar cells with different nitrogen additives at elevated temperatures - Can sterically hindered pyridines prevent dye degradation?

    Energy Technology Data Exchange (ETDEWEB)

    Tuyet Nguyen, Phuong; Lund, Torben [Department of Science, Systems and Models, Roskilde University, 4000 Roskilde (Denmark); Rand Andersen, Anders [University of Southern Denmark, Institute of Sensors, Signals and Electrotechnics (SENSE), Niels Bohrs Alle 1, 5230 Odense M (Denmark); Danish Technological Institute, Plastics Technology, Gregersensvej 2630 Taastrup (Denmark); Morten Skou, Eivind [University of Southern Denmark, Department of Chemical Engineering, Biotechnology and Enviromental Technology, Niels Bohrs Alle 1, 5230 Odense M (Denmark)

    2010-10-15

    The homogeneous kinetics of the nucleophilic substitution reactions between the ruthenium dye N719 and eight pyridines and 1-methylbenzimidazole have been investigated in 3-methoxypropionitrile at 100 C. The half lives of N719 with the additives 4-tert-butylpyridine (0.5 M) and 1-methylbenzimidazole (0.5 M) were 57 and 160 h, respectively. Sterically hindered pyridines like 2,6-lutidine did not react with N719. The efficiencies of dye-sensitized solar cells (DSC, area=8.0 cm{sup 2}) prepared with 1-methylbenzimidazole (MBI), 4-tert-butylpyridine (4-TBP), 2,6-lutidine and without any additive were 7.1%, 6.2%, 6.0% and 4.8%, respectively. The cells were stored in dark at 85 C and their I-V curves and impedance spectra were measured at regular time intervals. The N719 dye degradation in the cells were monitored by a new dye extraction protocol combined with analysis of the dye extract by HPLC coupled to mass spectrometry. After 300 h storage in dark at 85 C 40% of the initial amount of N719 dye was degraded in DSC cells prepared with MBI and the efficiency was decreased to 40% of its initial value. DSC cells prepared with 2,6-lutidine or no additives showed smaller thermal dye and efficiency stability at elevated temperatures than DSC cells prepared with the none sterically hindered additives MBI and 4-TBP. In the cells prepared with 2,6-lutidine or no additive higher contents of the iodo products [RuL{sub 2}(NCS)(iodide)]{sup +} and [RuL{sub 2}(3-MPN)(iodide)]{sup +} were found than in cells prepared with 4-TBP and MBI. It is suggested that sterically hindered pyridines have smaller complexation constants with I{sub 3}{sup -} than unsterically hindered additives. This may explain the observed faster nucleophilic substitution rates of uncomplexed I{sub 3}{sup -} with N719 in DSC cells prepared with sterically hindered pyridines. The EIS analysis showed that the lifetime of the injected electrons in the TiO{sub 2}{tau}{sub eff} is reduced by a thermally induced change

  7. Effects of liquid aluminum chloride additions to poultry litter on broiler performance, ammonia emissions, soluble phosphorus, total volatile Fatty acids, and nitrogen contents of litter.

    Science.gov (United States)

    Choi, I H; Moore, P A

    2008-10-01

    Recent studies have shown that the use of aluminum sulfate [alum, Al2(SO4)3.14H2O] and aluminum chloride (AlCl3) additions to animal manures are more effective than other chemicals in reducing ammonia (NH3) emissions and P solubility. Although the use of Al2(SO4)3.14H2O has been intensively used in the poultry industry for many years, no research has been conducted to evaluate the effect of liquid AlCl3 on these parameters. The objectives of this study were to determine the effects of applying liquid AlCl3 to poultry litter on 1) broiler performance, 2) NH3 fluxes, and 3) litter chemical characteristics, including soluble reactive P, total volatile fatty acids, and N content. Eight hundred broiler chicks were placed into 16 floor pens (50 birds/pen) in a single house for 6 wk. Liquid AlCl3 treatments were sprayed on the litter surface at rates of 100, 200, and 300 g of liquid AlCl3/kg of litter; un-treated litter served as controls. At the 2 lower rates, liquid AlCl3 treatments tended to improve weight gain and feed intake but had no effect on feed conversion or mortality, whereas the higher rate (300 g/kg of litter) had a negative effect on intake. Application of 100, 200, and 300 g of liquid AlCl3 reduced NH3 fluxes by 63, 76, and 76% during the 6-wk period, respectively, compared with the controls. Liquid AlCl3 additions reduced litter soluble reactive P contents by 24, 30, and 36%, respectively, at the low, medium, and high rates. Total volatile fatty acid contents (odor precursors) in litter were reduced by 20, 50, and 51%, respectively, with 100, 200, and 300 g of liquid AlCl3/kg of litter. Liquid AlCl3 additions increased total N, inorganic N, and plant available N contents in litter. These results indicate that liquid AlCl3 additions at the lower rates can provide significant positive environmental benefits to broiler operations. PMID:18809856

  8. 氮素补充对高寒草甸土壤团聚体有机碳、全氮分布的影响%Effect of organic carbon and total nitrogen distribution in alpine meadow soil aggregates with different nitrogen addition level

    Institute of Scientific and Technical Information of China (English)

    刘晓东; 尹国丽; 武均; 陈建纲; 何振刚; 师尚礼

    2015-01-01

    The alpine meadow, mainly distributed in cold and high altitude region in the Qinghai-Tibetan Plateau, is a grassland ecosystem with the largest area. In the past decade, the grassland and soil ecological environments were degraded continuously, which have been paid high attention by human beings. The reasons of grassland degradation are complex, and from the view of ecology, the degradation is mainly caused by the unbalance of energy flow and material circulation in grassland ecosystem. Grazing together with other human activities, lead to soil nutrient loss with the output of grass and livestock products. Due to the insufficient supply of nutrients, the decline of soil fertility seriously affects the grass growth in pasture, leading to grassland ecosystem health deteriorating. Nitrogen (N) is the main limiting factor of soil nutrient in the alpine meadow. N addition is an important means to maintain the balance of grassland soil nutrient, which in turn can increase soil N content, and stimulate the growth and distribution of aboveground biomass and belowground root system, thereby affecting the soil structure. Soil aggregates are the basic unit of soil structure, while carbon (C) and total N are the most important factors affecting the structure of soil aggregates. Therefore, relying on N addition experiment of 3 consecutive years located in Xiahe County in eastern Qinghai-Tibet Plateau, in order to explore the effects of N addition on the changing process of soil aggregates, organic C and total N, and its impacts on soil structure, the paper attempted to seek methods for maintaining the stability of soil structure in the alpine meadow. The experiment consisted of 4 treatments with different N addition levels: CK (0), LN (50 kg/hm2), MN (100 kg/hm2) and HN (200 kg/hm2), in which the randomized block design was applied and each processing was repeated for 3 times. The result showed that LN, MN and HN treatments improved the content of≥0.25 mm soil aggregate in 0

  9. 不同DMPP添加水平对土壤有机氮素转化的影响%Influence of Different DMPP Addition Level on Organic Nitrogen Transformation in the Soil

    Institute of Scientific and Technical Information of China (English)

    殷建祯; 俞巧钢; 符建荣; 马军伟; 叶静; 唐秋萍

    2012-01-01

    In order to improve the efficiency of nitrogen utilization and decrease the nitrogen loss,the influence of DMPP(3,4-dimethypyrazole phosphate) addition on soil nitrogen transformation under the organic fertilizers system were studied.Influence of DMPP addition on soil nitrogen transformation and ammonium oxidation inhibiting with different concentration of DMPP under the organic fertilizers system were studied by aerial soil incubation method.The results showed that,the process of nitration was obviously restrained with DMPP addition under the organic fertilizers system.The optimum efficiency of DMPP appeared on the 14th day.Compared to the treatment without DMPP addition,the NH+4-N content was increased by 2~3 times,meanwhile,the NO-3-N content was reduced by 2~3 times in those treatments with DMPP addition.Effects of nitrification inhibitor with DMPP addition showed a decreasing tendency after 14 days.Effects of DMPP on the nitrification inhibitor were enhanced with the increasing level of DMPP amount,but the inhibitory effect was no longer greatly enhanced when DMPP increased to a certain level above 2%.The optimize amount of DMPP was 1% to 2% in the organic fertilizers application in the agriculture production,concerning about the nitrification inhibitor effect and DMPP application level in the soil.%研究单施有机肥模式下,3,4-二甲基吡唑磷酸盐(DMPP)对土壤有机氮素转化的影响,为土壤氮素高效利用和减少损失提供科学依据。采用土壤恒温培养试验,研究单施有机肥条件下不同DMPP添加水平对土壤中有机氮素转化及硝化抑制效应的影响。结果表明,单施有机肥条件下,DMPP可明显抑制土壤硝化反应的进程。培养期间DMPP最佳硝化抑制效果出现在14d,与不添加DMPP的处理相比,添加DMPP的处理铵态氮含量增加2~3倍,硝态氮含量减少2~3倍。14d后DMPP硝化抑制效果逐渐减弱。DMPP对硝化反应的抑制效果及有效抑制时间随

  10. In situ sulfur isotopes (δ(34)S and δ(33)S) analyses in sulfides and elemental sulfur using high sensitivity cones combined with the addition of nitrogen by laser ablation MC-ICP-MS.

    Science.gov (United States)

    Fu, Jiali; Hu, Zhaochu; Zhang, Wen; Yang, Lu; Liu, Yongsheng; Li, Ming; Zong, Keqing; Gao, Shan; Hu, Shenghong

    2016-03-10

    The sulfur isotope is an important geochemical tracer in diverse fields of geosciences. In this study, the effects of three different cone combinations with the addition of N2 on the performance of in situ S isotope analyses were investigated in detail. The signal intensities of S isotopes were improved by a factor of 2.3 and 3.6 using the X skimmer cone combined with the standard sample cone or the Jet sample cone, respectively, compared with the standard arrangement (H skimmer cone combined with the standard sample cone). This signal enhancement is important for the improvement of the precision and accuracy of in situ S isotope analysis at high spatial resolution. Different cone combinations have a significant effect on the mass bias and mass bias stability for S isotopes. Poor precisions of S isotope ratios were obtained using the Jet and X cones combination at their corresponding optimum makeup gas flow when using Ar plasma only. The addition of 4-8 ml min(-1) nitrogen to the central gas flow in laser ablation MC-ICP-MS was found to significantly enlarge the mass bias stability zone at their corresponding optimum makeup gas flow in these three different cone combinations. The polyatomic interferences of OO, SH, OOH were also significantly reduced, and the interference free plateaus of sulfur isotopes became broader and flatter in the nitrogen mode (N2 = 4 ml min(-1)). However, the signal intensity of S was not increased by the addition of nitrogen in this study. The laser fluence and ablation mode had significant effects on sulfur isotope fractionation during the analysis of sulfides and elemental sulfur by laser ablation MC-ICP-MS. The matrix effect among different sulfides and elemental sulfur was observed, but could be significantly reduced by line scan ablation in preference to single spot ablation under the optimized fluence. It is recommended that the d90 values of the particles in pressed powder pellets for accurate and precise S isotope analysis

  11. Addition of proteic nitrogen during alcoholic fermentation for the production of cachaça Adição de nitrogênio protéico durante a fermentação alcoólica de caldo de cana para produção de cachaça

    Directory of Open Access Journals (Sweden)

    Elisangela Marques Jeronimo

    2008-04-01

    Full Text Available Cachaça is the denomination of a typical and exclusive Brazilian spirit produced from the distillation of fermented sugarcane juice must. The objective of this study was to evaluate the effect of adding yeast extract to the sugarcane juice used for sugarcane liquor production, because for the artisanal process no studies are available on nitrogen addition nor beverage quality, involving nitrogen complementation. Results of previous studies in the laboratory scale showed that sugarcane juice complementation with proteic nitrogen can be a beneficial practice for yeast multiplication and cellular growth, and also for the improvement of fermentation yield and liquor productivity. In this pilot scale study, using recycled yeast, the addition of proteic nitrogen influenced positively the cell viability, confirmed the yeast recycling operation, and also reduced the fermentation time. The proteic nitrogen addition did not affect the sensory acceptance of the distillate, and did not change the contents of volatile compounds, indicating that assimilable forms of proteic nitrogen can be helpfull to improve the alcoholic fermentation for cachaça production.Cachaça é a denominação de uma típica e exclusiva bebida destilada brasileira produzida a partir da destilação do caldo fermentado da cana-de-açúcar. O objetivo deste estudo foi avaliar a adição de extrato de levedura no mosto de caldo de cana para a produção de cachaça, pois em processo artesanal não há estudos específicos sobre as características fermentativas da levedura assim como sobre a qualidade da bebida, envolvendo a complementação nitrogenada e em específico a aplicação de nitrogênio protéico. Os resultados obtidos em trabalhos anteriores, conduzidos em laboratório, indicaram que nas destilarias artesanais de aguardente a complementação protéica do mosto pode constituir uma prática benéfica para a multiplicação e crescimento celular do fermento e conseq

  12. Nitrogen Inputs via Nitrogen Fixation in Northern Plants and Soils

    Science.gov (United States)

    Thorp, N. R.; Wieder, R. K.; Vile, M. A.

    2015-12-01

    Dominated by cold and often acidic water logged environments, mineralization of organic matter is slow in the majority of northern ecosystems. Measures of extractable ammonium and nitrate are generally low and can be undetectable in peat pore waters. Despite this apparent nitrogen limitation, many of these environments produce deep deposits of soil organic matter. Biological nitrogen fixation carried out by autotrophic and heterotrophic diazotrophs associated with cryptograms provides the majority of known nitrogen inputs in these northern ecosystems. Nitrogen fixation was assessed in a variety of northern soils within rhizospheres of dominant plant communities. We investigated the availability of this newly fixed nitrogen to the vascular plant community in nitrogen limited northern plant communities. We tracked nitrogen flow from 15N2 gas fixed in Sphagnum mosses into tissues of two native vascular plant species, boreal cranberry (Vaccinium oxycoccus) and black spruce (Picea mariana). 15N-labeled Sphagnum microcosms were grown within variable mesh size exclusion/inclusion fabrics in a nitrogen addition experiment in situ in order to investigate the role of mycorrhizal fungi in the uptake of newly fixed nitrogen. Up to 24% of daily fixed 15N label was transferred to vascular plant tissues during 2 months. Nitrogen addition resulted in decreased N2 fixation rates; however, with higher nitrogen availability there was a higher rate of 15N label uptake into the vascular plants, likely the result of increased production of dissolved organic nitrogen. Reliance on mycorrhizal networks for nitrogen acquisition was indicated by nitrogen isotope fractionation patterns. Moreover, N2 fixation activities in mosses were stimulated when vascular plants were grown in moss microcosms versus "moss only" treatments. Results indicate that bog vascular plants may derive considerable nitrogen from atmospheric N2 biologically fixed within Sphagnum mosses. This work demonstrates that

  13. Multiple splice variants within the bovine silver homologue (SILV gene affecting coat color in cattle indicate a function additional to fibril formation in melanophores

    Directory of Open Access Journals (Sweden)

    Weikard Rosemarie

    2007-09-01

    Full Text Available Abstract Background The silver homologue(SILV gene plays a major role in melanosome development. SILV is a target for studies concerning melanoma diagnostics and therapy in humans as well as on skin and coat color pigmentation in many species ranging from zebra fish to mammals. However, the precise functional cellular mechanisms, in which SILV is involved, are still not completely understood. While there are many studies addressing SILV function upon a eumelaneic pigment background, there is a substantial lack of information regarding the further relevance of SILV, e.g. for phaeomelanosome development. Results In contrast to previous results in other species reporting SILV expression exclusively in pigmented tissues, our experiments provide evidence that the bovine SILV gene is expressed in a variety of tissues independent of pigmentation. Our data show that the bovine SILV gene generates an unexpectedly large number of different transcripts occurring in skin as well as in non-pigmented tissues, e.g. liver or mammary gland. The alternative splice sites are generated by internal splicing and primarily remove complete exons. Alternative splicing predominantly affects the repeat domain of the protein, which has a functional key role in fibril formation during eumelanosome development. Conclusion The expression of the bovine SILV gene independent of pigmentation suggests SILV functions exceeding melanosome development in cattle. This hypothesis is further supported by transcript variants lacking functional key elements of the SILV protein relevant for eumelanosome development. Thus, the bovine SILV gene can serve as a model for the investigation of the putative additional functions of SILV. Furthermore, the splice variants of the bovine SILV gene represent a comprehensive natural model to refine the knowledge about functional domains in the SILV protein. Our study exemplifies that the extent of alternative splicing is presumably much higher than

  14. A forma de aplicação da uréia e dos resíduos vegetais afeta a disponibilidade de nitrogênio The addition form of crop residues and urea interfers on nitrogen availability

    Directory of Open Access Journals (Sweden)

    Paulo Roberto Ernani

    2005-04-01

    Full Text Available O método de aplicação dos resíduos vegetais e dos fertilizantes nitrogenados pode afetar as reações do nitrogênio no solo, principalmente no plantio direto. O presente trabalho objetivou avaliar esses efeitos na disponibilidade de N para o milho em dois solos, em casa-de-vegetação. Combinações de métodos (ausência, incorporada ou na superfície de adição de palha de aveia (0,4kg m-2 e uréia (50mg N kg-1 foram aplicadas em unidades experimentais (7dm³ vaso-1 de dois solos, perfazendo um fatorial 3 x 3 x 2. O milho foi semeado no dia da aplicação dos tratamentos e as plantas foram cultivadas durante trinta dias, sobre um Neossolo e um Nitossolo, respectivamente com 50 e 520g kg-1 de argila e 8 e 48g kg-1 de matéria orgânica. A aplicação de palha de aveia, principalmente sobre a superfície do solo, beneficiou o desenvolvimento das plantas, possivelmente pela manutenção de maior quantidade de umidade nos solos. A aplicação de uréia não afetou nenhum parâmetro vegetal no solo argiloso, talvez porque a decomposição da matéria orgânica liberou mais N do que a imobilização ocasionada durante a decomposição da palha; no solo arenoso, entretanto, a uréia foi benéfica quando incorporada ao solo, e prejudicial quando adicionada na superfície, provavelmente devido à toxidez de amônia. Dessa forma, o efeito da decomposição da palha de aveia na disponibilidade de N foi função do teor de matéria orgânica original do solo.Management of both crop residues and nitrogen fertilizers affects soil N reactions especially on no-till systems. The magnitude of these effects on N availability to maize was evaluated in a greenhouse study. Combinations of oat straw and urea (absence, soil incorporated or surface applied were added to experimental units (7-dm³ per pot of two soils, in a 3 x 3 x 2 factorial combination. Plants were sown just following treatments addition, and grown for thirty days in two soils (Typic

  15. Soil microbial biomass and community structure affected by repeated additions of sewage sludge in four Swedish long-term field experiments

    Science.gov (United States)

    Börjesson, G.; Kätterer, T.; Kirchmann, H.

    2012-04-01

    Soil organic matter is a key attribute of soil fertility. The pool of soil organic C can be increased, either by mineral fertilisers or by adding organic amendments such as sewage sludge. Sewage sludge has positive effects on agricultural soils through the supply of organic matter and essential plant nutrients, but sludge may also contain unwanted heavy metals, xenobiotic substances and pathogens. One obvious effect of long-term sewage sludge addition is a decrease in soil pH, caused by N mineralisation followed by nitrification, sulphate formation and presence of organic acids with the organic matter added. The objective of this study was to investigate the effect of sewage sludge on the microbial biomass and community structure. Materials and methods We analysed soil samples from four sites where sewage sludge has been repeatedly applied in long-term field experiments situated in different parts of Sweden; Ultuna (59°49'N, 17°39'E, started 1956), Lanna (58°21'N, 13°06'E, started 1997-98), Petersborg (55°32'N, 13°00'E, started 1981) and Igelösa (55°45'N, 13°18'E, started 1981). In these four experiments, at least one sewage sludge treatment is included in the experimental design. In the Ultuna experiment, all organic fertilisers, including sewage sludge, are applied every second year, corresponding to 4 ton C ha-1. The Lanna experiment has a similar design, with 8 ton dry matter ha-1 applied every second year. Lanna also has an additional treatment in which metal salts (Cd, Cu, Ni and Zn) are added together with sewage sludge. At Petersborg and Igelösa, two levels of sewage sludge (4 or 12 ton dry matter ha-1 every 4th year) are compared with three levels of NPK fertiliser (0 N, ½ normal N and normal N). Topsoil samples (0-20 cm depth) from the four sites were analysed for total C, total N, pH and PLFAs (phospholipid fatty acids). In addition, crop yields were recorded. Results At all four sites, sewage sludge has had a positive effect on crop yields

  16. Nutritional Performance of Cattle Grazing during Rainy Season with Nitrogen and Starch Supplementation.

    Science.gov (United States)

    Lazzarini, Ísis; Detmann, Edenio; de Campos Valadares Filho, Sebastião; Paulino, Mário Fonseca; Batista, Erick Darlisson; de Almeida Rufino, Luana Marta; Dos Reis, William Lima Santiago; de Oliveira Franco, Marcia

    2016-08-01

    The objective of this work was to evaluate the effects of supplementation with nitrogen and starch on the nutritional performance of grazing cattle during the rainy season. Five rumen cannulated Nellore steers, averaging 211 kg of body weight (BW), were used. Animals grazed on five signal grass paddocks. Five treatments were evaluated: control (forage only), ruminal supplementation with nitrogen at 1 g of crude protein (CP)/kg BW, ruminal supplementation with starch at 2.5 g/kg BW, supplementation with nitrogen (1 g CP/kg BW) and starch (2.5 g/kg BW), and supplementation with nitrogen (1 g CP/kg BW) and a mixture of corn starch and nitrogenous compounds (2.5 g/kg BW), thereby resulting in an energy part of the supplement with 150 g CP/kg of dry matter (DM). This last treatment was considered an additional treatment. The experiment was carried out according to a 5 ×5 Latin square design following a 2×2+1 factorial arrangement (with or without nitrogen, with or without starch, and the additional treatment). Nitrogen supplementation did not affect (p>0.10) forage intake. Starch supplementation increased (pbalance (NB) was increased (p0.10), NB obtained with nitrogen plus starch supplementation was greater than NB obtained with either nitrogen or starch exclusive supplementation. Supplementation with starch and nitrogen to beef cattle grazing during the rainy season can possibly improve digestion and nitrogen retention in the animal.. PMID:26954147

  17. Age and sex affect protein metabolism at protein intakes that span the range of adequacy: comparison of leucine kinetics and nitrogen balance data☆

    OpenAIRE

    Conley, Travis B.; McCabe, George P; Lim, Eunjung; Yarasheski, Kevin E; Johnson, Craig A; Campbell, Wayne W

    2012-01-01

    Research suggests that changes in leucine oxidation (leuox) with feeding may reflect adult protein requirements. We evaluated this possibility by assessing the effects of age, sex, and different protein intakes on whole-body leucine kinetics and nitrogen balance. Thirty-four young (n = 18, 22–46 years) and old (n= 16, 63–81 years) men and women completed three 18-day trials with protein intakes of 0.50, 0.75 and 1.00 g protein·kg body weight−1·d−1. Fasting and fed-state leucine kinetics were ...

  18. Symbiotic nitrogen fixation and yield of Pachyrhizus Erosus (L) urban cultivars and Pachyrhizus Ahipa (WEDD) parodi landraces as affected by flower pruning

    DEFF Research Database (Denmark)

    Castellanos, J.Z.; Zapata, F.; Badillo, V.; Peña-Cabriales, J.J.; Jensen, E.S.; Heredia-Gacia, E.

    Pachyrhizus ahipa and Pachyrhizus erosus are tuber legume crops with high yield potential, high nutritional value, low N fertiliser and low pesticide requirement and have a potential use in worldwide cultivation. One of the main advantages of these two crop species are their ability to produce high...... reference crops. In the second experiment N-15 isotopic dilution methodology was used to determine N-2 fixation in the same cultivars as in Experiment 1, using the same reference crops, but tuber legumes were only grown with pruning of flowers. In the first experiment the amounts of nitrogen fixed ranged...

  19. 侵蚀泥沙、有机质和全氮富集规律%The enrichments of organic matter and total nitrogen in sediment as affected by relavant factors

    Institute of Scientific and Technical Information of China (English)

    张兴昌; 郑纪勇; 李世清

    2004-01-01

    Serious soil erosion has already resulted in degradation of the Loess Plateau of China. Soil erosion is commonly accompanied by extensive soil nutrient loss. Because of enrichment processes,sediment nutrient content is often higher than that of natural soil. The objective of this study is to determine the enrichments of organic matter and total nitrogen in sediment in hilly and gully loess areas on the Loess Plateau of China. Measurements of enrichment ratios (ER) of organic matter (EROM) and total nitrogen (ERTN) in sediment as affected by rainfall, slope gradient, tillage, and fertilization were made in the field under natural rainfall conditions. The results showed that the enrichment of clay in sediment resulted in the enrichment of organic matter (OM) and total nitrogen (TN) in sediment. The averages of sediment clay ER, EROM and ERTN for the various slope gradients were 1.77, 2.09 and 1.61, respectively. The soil erosive module was negatively correlated with EROM and ERTN. Our results indicate that measures to reduce soil erosion, i.e. reducing rainfall erosivity, decreasing soil slope gradient, decreasing fertilizer use, and using level trenches, may increase EROM and ERTN. Both quantity and quality of sediment yield should be considered when implementing erosion control measures.

  20. Seasonal Variations in Nitrogen and Phosphorus Loads of Akçalar (Musa Creek and the Affects of the Lake Uluabat

    Directory of Open Access Journals (Sweden)

    Aslıhan KÂTİP

    2013-08-01

    Full Text Available Domestic, slaughter house and industrial waste waters of Akçalar town near the Lake Uluabat which has an international importance and subject to the Ramsar agreement is discharged to Lake Uluabat through the Akçalar Creek. Akçalar Creek pollutes the eastern part of the lake and reduces the water quality. In this study, flow rates, TN (total nitrogen, NH4-N, NO3-N, TP, PO4-P concentrations and pollution loads of Akçalar Creek were measured during the period 2008-2009. Loads of TN, NH4-N, NO3-N, TP and PO4-P were calculated as 22.45 tones/year, 3.14 tones/year,3.04 tones/year, 0.58 tones/year, and 0.46 tones/year respectively. The highest pollution loads for nitrogen and phosphorus fractions were determined in March. In order to prevent the pollution of Lake Uluabat and Akçalar Creek and reduce the pollution loads, domestic and industrial wastewater treatment plants should be done as soon as possible and using of fertilizers and pesticides in agricultural activities should be restricted. Also, some studies for European Union Water Framework Directive should be started

  1. Addition of proteic nitrogen during alcoholic fermentation for the production of cachaça Adição de nitrogênio protéico durante a fermentação alcoólica de caldo de cana para produção de cachaça

    OpenAIRE

    Elisangela Marques Jeronimo; Evelyn de Souza Oliveira; Elson Luíz Rocha Souza; Marcelo de Almeida Silva; Gil Eduardo Serra

    2008-01-01

    Cachaça is the denomination of a typical and exclusive Brazilian spirit produced from the distillation of fermented sugarcane juice must. The objective of this study was to evaluate the effect of adding yeast extract to the sugarcane juice used for sugarcane liquor production, because for the artisanal process no studies are available on nitrogen addition nor beverage quality, involving nitrogen complementation. Results of previous studies in the laboratory scale showed that sugarcane juice c...

  2. Tensile Deformation Behavior and Phase Transformation in the Weld Coarse-Grained Heat-Affected Zone of Metastable High-Nitrogen Fe-18Cr-10Mn-N Stainless Steel

    Science.gov (United States)

    Moon, Joonoh; Lee, Tae-Ho; Park, Seong-Jun; Jang, Jae-il; Jang, Min-Ho; Ha, Heon-Young; Hwang, Byoungchul

    2013-07-01

    The tensile deformation behavior and phase transformation in the weld coarse-grained heat-affected zone (CGHAZ) of a metastable high-nitrogen austenitic stainless steel was explored through tensile tests, nanoindentation experiments, and transmission electron microscopy analysis. True stress-strain response during tensile test was found to be seriously affected by δ-ferrite fraction, which depends on peak temperature of the CGHAZs. The strain-induced martensitic transformation (SIMT) occurred in base steel, whereas the SIMT disappeared and deformation twinning occurred predominantly in the CGHAZs. The relationship among true stress-strain response, nanoindentation hardness, and deformed microstructures was carefully investigated and discussed in terms of changes of stacking fault energy.

  3. THE ADDITION OF MILK OR YOGURT TO A PLANT-BASED DIET INCREASES ZINC BIOAVAILABILITY BUT DOES NOT AFFECT IRON BIOAVAILABILITY IN WOMEN

    Science.gov (United States)

    The addition of milk and milk-based products to the diets of individuals subsisting on plant-based diets was reported to have positive effects on nutritional status and functional outcomes such as growth, morbidity, and cognition. We examined the effect of the addition of milk or yogurt on the bioav...

  4. Resposta do dendezeiro à adição de nitrogênio e sua influência na população de bactérias diazotróficas Response of African oil palm to nitrogen addition and its influence on the diazotrophic bacteria population

    Directory of Open Access Journals (Sweden)

    André Vieira de Carvalho

    2006-02-01

    Full Text Available O dendê (Elaeis guineensis, Jaquim pode produzir até sete toneladas de óleo por hectare por ano. O óleo vegetal é muito versátil e pode ser usado desde a indústria alimentícia até a produção de biocombustíveis. A planta é capaz de se associar com bactérias diazotróficas que colonizam raízes e caules. O objetivo deste trabalho foi avaliar a resposta à adubação nitrogenada de 17 genótipos de dendê no primeiro ano de cultivo e avaliar a influência da adição do N mineral sobre a população de bactérias diazotróficas, naturalmente presentes nas plântulas de dendezeiro. Foram utilizados potes de plástico completados com 50% de areia quartzoza e 50% de horizonte B de um Argissolo Vermelho-Amarelo, série Itaguaí, não esterilizado e extremamente pobre em nitrogênio. A uréia foi aplicada na dosagem de 33,68 kg ha-1 de N. Na presença do N, todos os genótipos melhoram os parâmetros biométricos, e houve aumento tanto do N total quanto do N acumulado. As populações de bactérias diazotróficas não foram influenciadas pela adição desse elemento. Dois genótipos foram selecionados, na presença e ausência de N, respectivamente, C-2001 e La Mé.African oil palm (Elaeis guineensis, Jaquim can produce up to 7 tons of oil per hectare per year. The vegetable oil is greatly versatile in its use, since food industry up to the production of fuels favorable to environmental protection. The plant has the potential to be associative with diazotrophic bacteria which colonize the roots and stem. The objective of this work was to evaluate 17 genotypes of E. guineensis in response to nitrogen addition and to verify the influence of this nitrogen on the diazotrophic population in an experiment using plastic pots filled with 50% quartz sand and 50% of non sterilized Horizon B; Red-Yellow Podzolic Soil series Itaguaí, extremely poor in nitrogen. Urea was used at a dose of 33.68 kg ha-1 de N. In the presence of the nitrogen, all

  5. Turnover of manure 15N-labelled ammonium during composting and soil application as affected by lime and superphosphate addition

    DEFF Research Database (Denmark)

    Tran, Tien Minh; Luxhøi, Jesper; Jensen, Lars Stoumann

    2012-01-01

    To determine N turnover and losses during aerobic composting of animal manure, a 41-d laboratory study was performed on pig manure composting with three additive treatments (Straw: pig manure + straw only; Lime: pig manure + straw + quick lime; and SSP: pig manure + straw + single superphosphate...... superphosphate increased the NH4-N content in both. Therefore, superphosphate addition increased the potential fertilizer value of composted pig manure. © Soil Science Society of America....

  6. 有机肥氮素矿化及影响因素研究进展%A review on nitrogen mineralization of organic manure and affecting factors

    Institute of Scientific and Technical Information of China (English)

    李玲玲; 李书田

    2012-01-01

    incubation methods did not destroyed soil texture, but might underestimated N mineralization potential. Leaching aerobic incubation method simulating plan uptake to periodically remove the mineralized N was suitable for rapid test but might overestimate the organic N mineralization potential. In situ culture in the field includes polyethylene bag incubation, top-open buried pipes and ion exchange resin methods. Polyethylene bag incubation method has been popular but has disadvantages such as waterproof, destroying soil texture and nitrate leaching loss. Top-open buried pipes method was permeable and protected soil texture from destroyed, but nitrate leaching loss was unavoidable. Ion exchange resin method incubating without destroying soil texture, although time and labor consuming, was sensitive to soil temperature, moisture, aeration and eliminated the impact of nitrate accumulation. Factors affecting manure N mineralization include manure characteristics, temperature, moisture, soil texture and fertilizer application. Studies mainly focused on the effect of different animal manures, compost maturity, C/N ratio and organic compounds on N mineralization. It is reasonable to use accumulative temperature to express the relationship between temperature and N mineralization.Studies on moisture mainly in the effect of alternation of wetting and drying conditions, soil texture mainly in relationship between clay content and N mineralization, and fertilization mainly on clay mineral fixed N as affect by N or K fertilizer additions. In summary, the studies in the future will focus on relationship between organic N mineralization and organic N components, plant availability of mineralized N, manure substitution equivalence and rate for fertilizer N and how the incubation results in lab will be applied in the field.

  7. Storage and Remobilization of Nitrogen by Chinese Jujube (Z.jujuba Mill.var.inermis Rehd) Seedling as Affected by Timing of 15N Supply

    Institute of Scientific and Technical Information of China (English)

    ZHAO Deng-chao; JIANG Yuan-mao; PENG Fu-tian; ZHANG Jin; ZHANG Xu; SUI Jing; HE Nai-bo

    2006-01-01

    Winter jujube orchard nitrogen (N) management aims at increasing N reserves to meet the tree's growth requirements.Fertilization strategies should maximize the efficiency of fertilizers,including the choice of the optimal timing of N supply.15N-urea was applied to winter jujubes on Jinsixiaozao jujubes rootstock to evaluate the effect of application timing on N-storage and remobilization in mature trees in pot culture. The treatments consisted of ground application before budding (BB), during fruit core-hardening stage (FCH), and fruit rapid-swelling stage (FRS). Nitrogen-use efficiency of treatments were significantly different, which were 2.42% (BB), 9.77% (FCH), and 9.01% (FRS) in the dormant and 5.20% (BB), 16.16%(FCH), and 10.30% (FRS) in the following full-bloom. N supply in the pre-harvest helped to increase N-reserves of trees and then translocate to the new growth organs the following year. The largest amount of 15N was detected in the roots and trunks. In all the treatments, the partition rates were highest in coarse roots, which were 30.43% (BB), 38.61% (FCH),and 40.62% (FRS), respectively. 15N stored in roots and trunks was used by jujube trees to sustain new growth in the following full-bloom. 15N applied before budding resulted in lower Ndff% in perennial organs (trunks and coarse roots)sampled in the following full-bloom, but fine roots had highest Ndff% (1.28%). Other organs recovered similar amount of Ndff%. In contrast, FCH and FRS treatments led to higher Ndff% (4.01-5.15%) in the new growth organs (new growth branches, deciduous spurs, leaves and flowers), but lower Ndff% in perennial branches (1.49-2.89%). With the delay of 15N-urea application time, 15N increased the partitioning to roots. FCH treatment increased N-storage in perennial organ during winter, which should be remobilized to sustain new growth the following spring.

  8. Net global warming potential and greenhouse gas intensity in a double cropping cereal rotation as affected by nitrogen and straw management

    Science.gov (United States)

    Huang, T.; Gao, B.; Christie, P.; Ju, X.

    2013-08-01

    The effects of nitrogen and straw management on global warming potential (GWP) and greenhouse gas intensity (GHGI) in a winter wheat-summer maize double-cropping system on the North China Plain were investigated. We measured nitrous oxide (N2O) emissions and studied net GWP (NGWP) and GHGI by calculating the net exchange of CO2 equivalent (CO2-eq) from greenhouse gas emissions, agricultural inputs and management practices, and changes in soil organic carbon (SOC), based on a long-term field experiment established in 2006. The field experiment includes six treatments with three fertilizer N levels (zero-N control, optimum and conventional N) and straw removal (i.e. N0, Nopt and Ncon) or return (i.e. N0, Nopt and SNcon). Optimum N management (Nopt, SNopt) saved roughly half of the fertilizer N compared to conventional agricultural practice (Ncon, SNcon) with no significant effect on grain yields. Annual mean N2O emissions reached 3.90 kg N2O-N ha-1 in Ncon and SNcon, and N2O emissions were reduced by 46.9% by optimizing N management of Nopt and SNopt. Straw return increased annual mean N2O emissions by 27.9%. Annual SOC sequestration was 0.40-1.44 Mg C ha-1 yr-1 in plots with N application and/or straw return. Compared to the conventional N treatments the optimum N treatments reduced NGWP by 51%, comprising 25% from decreasing N2O emissions and 75% from reducing N fertilizer application rates. Straw return treatments reduced NGWP by 30% compared to no straw return because the GWP from increments of SOC offset the GWP from higher emissions of N2O, N fertilizer and fuel after straw return. The GHGI trends from the different nitrogen and straw management practices were similar to the NGWP. In conclusion, optimum N and straw return significantly reduced NGWP and GHGI and concomitantly achieved relatively high grain yields in this important winter wheat-summer maize double-cropping system.

  9. Net global warming potential and greenhouse gas intensity in a double-cropping cereal rotation as affected by nitrogen and straw management

    Science.gov (United States)

    Huang, T.; Gao, B.; Christie, P.; Ju, X.

    2013-12-01

    The effects of nitrogen and straw management on global warming potential (GWP) and greenhouse gas intensity (GHGI) in a winter wheat-summer maize double-cropping system on the North China Plain were investigated. We measured nitrous oxide (N2O) emissions and studied net GWP (NGWP) and GHGI by calculating the net exchange of CO2 equivalent (CO2-eq) from greenhouse gas emissions, agricultural inputs and management practices, as well as changes in soil organic carbon (SOC), based on a long-term field experiment established in 2006. The field experiment includes six treatments with three fertilizer N levels (zero N (control), optimum and conventional N) and straw removal (i.e. N0, Nopt and Ncon) or return (i.e. SN0, SNopt and SNcon). Optimum N management (Nopt, SNopt) saved roughly half of the fertilizer N compared to conventional agricultural practice (Ncon, SNcon), with no significant effect on grain yields. Annual mean N2O emissions reached 3.90 kg N2O-N ha-1 in Ncon and SNcon, and N2O emissions were reduced by 46.9% by optimizing N management of Nopt and SNopt. Straw return increased annual mean N2O emissions by 27.9%. Annual SOC sequestration was 0.40-1.44 Mg C ha-1 yr-1 in plots with N application and/or straw return. Compared to the conventional N treatments the optimum N treatments reduced NGWP by 51%, comprising 25% from decreasing N2O emissions and 75% from reducing N fertilizer application rates. Straw return treatments reduced NGWP by 30% compared to no straw return because the GWP from increments of SOC offset the GWP from higher emissions of N2O, N fertilizer and fuel after straw return. The GHGI trends from the different nitrogen and straw management practices were similar to the NGWP. In conclusion, optimum N and straw return significantly reduced NGWP and GHGI and concomitantly achieved relatively high grain yields in this important winter wheat-summer maize double-cropping system.

  10. Net global warming potential and greenhouse gas intensity in a double cropping cereal rotation as affected by nitrogen and straw management

    Directory of Open Access Journals (Sweden)

    T. Huang

    2013-08-01

    Full Text Available The effects of nitrogen and straw management on global warming potential (GWP and greenhouse gas intensity (GHGI in a winter wheat–summer maize double-cropping system on the North China Plain were investigated. We measured nitrous oxide (N2O emissions and studied net GWP (NGWP and GHGI by calculating the net exchange of CO2 equivalent (CO2-eq from greenhouse gas emissions, agricultural inputs and management practices, and changes in soil organic carbon (SOC, based on a long-term field experiment established in 2006. The field experiment includes six treatments with three fertilizer N levels (zero-N control, optimum and conventional N and straw removal (i.e. N0, Nopt and Ncon or return (i.e. N0, Nopt and SNcon. Optimum N management (Nopt, SNopt saved roughly half of the fertilizer N compared to conventional agricultural practice (Ncon, SNcon with no significant effect on grain yields. Annual mean N2O emissions reached 3.90 kg N2O-N ha−1 in Ncon and SNcon, and N2O emissions were reduced by 46.9% by optimizing N management of Nopt and SNopt. Straw return increased annual mean N2O emissions by 27.9%. Annual SOC sequestration was 0.40–1.44 Mg C ha−1 yr−1 in plots with N application and/or straw return. Compared to the conventional N treatments the optimum N treatments reduced NGWP by 51%, comprising 25% from decreasing N2O emissions and 75% from reducing N fertilizer application rates. Straw return treatments reduced NGWP by 30% compared to no straw return because the GWP from increments of SOC offset the GWP from higher emissions of N2O, N fertilizer and fuel after straw return. The GHGI trends from the different nitrogen and straw management practices were similar to the NGWP. In conclusion, optimum N and straw return significantly reduced NGWP and GHGI and concomitantly achieved relatively high grain yields in this important winter wheat–summer maize double-cropping system.

  11. Nitrogen Fixed by Pea Plant as Affected by Lead,Cadmium and Rates of N-Fertilizer Using 15N Tracer Technique

    International Nuclear Information System (INIS)

    A pot experiment was carried out in greenhouse to investigate the effect Pb and Cd applied on growth, yield and the amount of fixed nitrogen by pea's plants.15N-labelled (5 % atom excess) ammonium nitrate was applied at three levels (0,20 and 40 mg N-1 kg soil). The legume pea seeds were inoculated with Rhizobium Leguminesarum. Lead was applied as lead sulfate at rates of 0, 50 and 200 mg Pb kg-1 soil, while the cadmium applied as cadmium sulfate at rates of 0, 5 and 10 mg Cd kg-1 soil. Results indicated that the highest values of Pb uptake were 540,11.55 and 552 mg-1 pot for pea shoot, pods and whole plant at the rate of 200 mg Pb kg-1 soil + 40 mg N kg-1 soil, respectively, While, the highest values of Cd-uptake were 13.90, 6.54 and 20 mg-1 pot at the rate of 10 mg Cd kg-1 + 20 mg N kg-1 soil for the same sequence. The values of Ndff and Ndfa were 43.74 and 278.2 while Ndfs recorded 164.1 mg pot-1 at rate of 5 mg Cd kg-1soil + 40 mg N kg-1 soil compared to the control.

  12. The pH change in rhizosphere of Pinus koraiensis seedlings as af-fected by different nitrogen sources and its effect on phosphorus availability

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Root mat method described by Kuchenbuch and Jungk was used to study the rhizosphere processes. The experiment was carried out on two years old Pinus koraiensis seedlings. Soil samples collected from the upper 20-cm soil layer in Changbai Mountain were treated with three different forms of nitrogen fertilizers: NO3--N, NH4+-N and NH4NO3. The results showed that the soil pH and available P near the roots were all lower than in the bulk soil in control treatment. NH4+-N application greatly de-creased the soil pH near the roots compared to the control treatment and promoted the absorption of phosphorus, which led to a more remarkable depletion region of available P. On the contrary, the rhizosphere soil pH was higher than in the bulk soil in treatments with NO3--N and retarded the P absorption, which led to a nearly equal available P contents to the bulk soil. In treat-ment with NH4NO3, the rhizosphere soil pH was only a little lower than that in the control treatment and its effects on P absorp-tion is mediate between the treatments with NH4+-N and NO3--N.

  13. Outpatient Management of Postbiopsy Pneumothorax with Small-Caliber Chest Tubes: Factors Affecting the Need for Prolonged Drainage and Additional Interventions

    International Nuclear Information System (INIS)

    The aim of this study was to evaluate the efficacy of outpatient management of postbiopsy pneumothoraces with small-caliber chest tubes and to assess the factors that influence the need for prolonged drainage or additional interventions.We evaluated the medical records of patients who were treated with small-caliber chest tubes attached to Heimlich valves for pneumothoraces resulting from image-guided transthoracic needle biopsy to determine the hospital admission rates, the number of days the catheters were left in place, and the need for further interventions. We also evaluated the patient, lesion, and biopsy technique characteristics to determine their influence on the need for prolonged catheter drainage or additional interventions. Of the 191 patients included in our study, 178 (93.2%) were treated as outpatients. Ten patients (5.2%) were admitted for chest tube-related problems, either for underwater suction (n = 8) or for pain control (n = 2). No further interventions were required in 146 patients (76.4%), with successful removal of the chest tubes the day after the biopsy procedure. Prolonged catheter drainage (mean, 4.3 days) was required in 44 patients (23%). Nineteen patients (9.9%) underwent additional interventions for management of pneumothorax. Presence of emphysema was noted more frequently in patients who required additional interventions or prolonged chest tube drainage than in those who did not (51.1% vs. 24.7%; p = 0.001).We conclude that use of the Heimlich valve allows safe and successful outpatient treatment of most patients requiring chest tube placement for postbiopsy pneumothorax. Additional interventions or prolonged chest tube drainage are needed more frequently in patients with emphysema in the needle path

  14. Outpatient management of postbiopsy pneumothorax with small-caliber chest tubes: factors affecting the need for prolonged drainage and additional interventions.

    Science.gov (United States)

    Gupta, Sanjay; Hicks, Marshall E; Wallace, Michael J; Ahrar, Kamran; Madoff, David C; Murthy, Ravi

    2008-01-01

    The aim of this study was to evaluate the efficacy of outpatient management of postbiopsy pneumothoraces with small-caliber chest tubes and to assess the factors that influence the need for prolonged drainage or additional interventions. We evaluated the medical records of patients who were treated with small-caliber chest tubes attached to Heimlich valves for pneumothoraces resulting from image-guided transthoracic needle biopsy to determine the hospital admission rates, the number of days the catheters were left in place, and the need for further interventions. We also evaluated the patient, lesion, and biopsy technique characteristics to determine their influence on the need for prolonged catheter drainage or additional interventions. Of the 191 patients included in our study, 178 (93.2%) were treated as outpatients. Ten patients (5.2%) were admitted for chest tube-related problems, either for underwater suction (n = 8) or for pain control (n = 2). No further interventions were required in 146 patients (76.4%), with successful removal of the chest tubes the day after the biopsy procedure. Prolonged catheter drainage (mean, 4.3 days) was required in 44 patients (23%). Nineteen patients (9.9%) underwent additional interventions for management of pneumothorax. Presence of emphysema was noted more frequently in patients who required additional interventions or prolonged chest tube drainage than in those who did not (51.1% vs. 24.7%; p = 0.001). We conclude that use of the Heimlich valve allows safe and successful outpatient treatment of most patients requiring chest tube placement for postbiopsy pneumothorax. Additional interventions or prolonged chest tube drainage are needed more frequently in patients with emphysema in the needle path. PMID:18074173

  15. Nitrogen Band Assignments for Presolar and Carbonado Diamonds

    CERN Document Server

    Garai, Jozsef; Chen, Jiuhua

    2010-01-01

    Presolar and carbonado diamonds formed in hydrogen rich environment and received severe radiation dose. It is suggested that these environmental affects altered the Substitutional N0 defect to Substitutional N+H defect by ionizing the nitrogen due to irradiation and by hydrogenating the ionized nitrogen. The bands of the substitutional N+H defect are deduced by red shifting the irradiation induced N+ bands due to the mass of the additional Hydrogen. The identified six bands induced by the N+H defects are present in both the presolar and the carbonado diamond spectra. The assignment of the substitutional N+H bands identifies all of the nitrogen related bands in the spectra, which shows that presolar and carbonado diamonds contain almost exclusively single nitrogen impurities. Thus these diamonds can be classified as type Ib. The substitutional N+H induced bands can be used to identify diamonds in space.

  16. Investigation of friction affected by additives in turbulent flows in pipelines; Investigacao da reducao de arrasto por aditivos em escoamentos turbulentos em dutos

    Energy Technology Data Exchange (ETDEWEB)

    Andreotti, Marcelo; Cunha, Francisco Ricardo da; Sousa, Aldo Joao de [Universidade de Brasilia, DF (Brazil). Dept. de Engenharia Mecanica; Universidade de Brasilia, DF (Brazil). Vortex: Grupo de Mecanica dos Fluidos de Escoamentos Complexos]. E-mails: andreotti@unb.br; frcunha@unb.br; aldo@unb.br

    2003-06-01

    The present study concerns reduction of friction in turbulent flows. This friction-reducing effect is obtained by adding fibers or polymers with high molecular weight that generate a tension anisotropy in the flow in the flow, diminishing the transport efficiency of momentum carried due to turbulent fluctuations. An analysis is undertaken based on a nonlinear constitutive model, which takes into account the rate of extra deformation of the flow in the direction of local orientation of the additives. The model is applied to develop an extension of the theory of Karman-Prandtl. The objective is to investigate a first effect of the additives on the flow. The results predicted by the model were adjusted by means of experimental data, showing a 65% reduction in the friction factor for a concentration of 350 ppm of Polyacrylamide. (author)

  17. Do soil organic carbon levels affect potential yields and nitrogen use efficiency? An analysis of winter wheat and spring barley field trials

    DEFF Research Database (Denmark)

    Oelofse, Myles; Markussen, Bo; Knudsen, Leif;

    2015-01-01

    Soil organic carbon (SOC) is broadly recognised as an important parameter affecting soil quality, and can therefore contribute to improving a number of soil properties that influence crop yield. Previous research generally indicates that soil organic carbon has positive effects on crop yields, but...... in many studies it is difficult to separate the effect of nutrients from the effect of SOC in itself. The aim of this study was to analyze whether the SOC content, in itself, has a significant effect on potential yields of commonly grown cereals across a wider range of soil types in Denmark. The...... yield, the yield with no fertiliser N application and the N use efficiency would be positively affected by SOC level. A statistical model was developed to explore relationships between SOC and potential yield, yields at zero N application and N use efficiency (NUE). The model included a variety of...

  18. Nitrogen starvation affects bacterial adhesion to soil Adesão de bactérias desnutridas por nitrogênio a solo

    OpenAIRE

    Maria Tereza Borges; Antônio Galvão Nascimento; Ulisses Nunes Rocha; Marcos Rogério Tótola

    2008-01-01

    One of the main factors limiting the bioremediation of subsoil environments based on bioaugmentation is the transport of selected microorganisms to the contaminated zones. The characterization of the physiological responses of the inoculated microorganisms to starvation, especially the evaluation of characteristics that affect the adhesion of the cells to soil particles, is fundamental to anticipate the success or failure of bioaugmentation. The objective of this study was to investigate the ...

  19. Route of tracer administration does not affect ileal endogenous nitrogen recovery measured with the 15N-isotope dilution technique in pigs fed rapidly digestible diets.

    Science.gov (United States)

    Steendam, C A Carina; Verstegen, Martin W A; Tamminga, Seerp; Boer, Huug; van 't End, Marianne; Verstappen, Berthe; Caine, William R; Visser, G Henk

    2004-11-01

    The (15)N-isotope dilution technique ((15)N-IDT), with either pulse-dose oral administration or continuous i.v. administration of [(15)N]-l-leucine (carotid artery), both at 5 mg/(kg body weight . d), was used to measure ileal (postvalve T-cecum cannula) endogenous nitrogen recovery (ENR) in pigs (9 +/- 0.6 kg). Diets were cornstarch, enzyme-hydrolyzed casein with no (control) or high (4%) content of quebracho extract (Schinopsis spp.) rich in condensed tannins. Blood was sampled from a catheter in the external jugular vein. Mean plasma (15)N-enrichment at d 8-10 was higher (P = 0.0009) after i.v. than after oral administration [0.0356 vs. 0.0379 atom% excess (APE)]. Plasma (15)N-enrichment for i.v. infused pigs was 0.01117 APE higher (P quebracho diet (69.5%). ENR was calculated from the ratio of (15)N-enrichment of plasma and digesta. The ENR for the quebracho diet was approximately 300% higher than for the control diet (6.03 vs. 1.94 g/kg dry matter intake, P < 0.001). The real N digestibility (92.2 +/- 0.4%) was equal for both diets (P = 0.1030) and both tracer methods (P = 0.9730). We concluded that oral administration of [(15)N]leucine provides reasonable estimates of ENR in pigs fed semipurified diets with high or low content of tannins; however, one must be careful in extrapolating this conclusion to studies with other protein sources or feeding frequencies. PMID:15514277

  20. How does the addition of steric hindrance to a typical N-heterocyclic carbene ligand affect catalytic activity in olefin metathesis?

    KAUST Repository

    Poater, Albert

    2013-01-01

    Density functional theory (DFT) calculations were used to predict and rationalize the effect of the modification of the structure of the prototype 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) N-heterocyclic carbene (NHC) ligand. The modification consists in the substitution of the methyl groups of ortho isopropyl substituent with phenyl groups, and here we plan to describe how such significant changes affect the metal environment and therefore the related catalytic behaviour. Bearing in mind that there is a significant structural difference between both ligands in different olefin metathesis reactions, here by means of DFT we characterize where the NHC ligand plays a more active role and where it is a simple spectator, or at least its modification does not significantly change its catalytic role/performance. © 2013 The Royal Society of Chemistry.

  1. Novel Flow Cytometry Analyses of Boar Sperm Viability: Can the Addition of Whole Sperm-Rich Fraction Seminal Plasma to Frozen-Thawed Boar Sperm Affect It?

    Science.gov (United States)

    Torres, Mariana Andrade; Díaz, Rommy; Boguen, Rodrigo; Martins, Simone Maria Massami Kitamura; Ravagnani, Gisele Mouro; Leal, Diego Feitosa; Oliveira, Melissa de Lima; Muro, Bruno Bracco Donatelli; Parra, Beatriz Martins; Meirelles, Flávio Vieira; Papa, Frederico Ozanan; Dell'Aqua, José Antônio; Alvarenga, Marco Antônio; Moretti, Aníbal de Sant'Anna; Sepúlveda, Néstor; de Andrade, André Furugen Cesar

    2016-01-01

    Boar semen cryopreservation remains a challenge due to the extension of cold shock damage. Thus, many alternatives have emerged to improve the quality of frozen-thawed boar sperm. Although the use of seminal plasma arising from boar sperm-rich fraction (SP-SRF) has shown good efficacy; however, the majority of actual sperm evaluation techniques include a single or dual sperm parameter analysis, which overrates the real sperm viability. Within this context, this work was performed to introduce a sperm flow cytometry fourfold stain technique for simultaneous evaluation of plasma and acrosomal membrane integrity and mitochondrial membrane potential. We then used the sperm flow cytometry fourfold stain technique to study the effect of SP-SRF on frozen-thawed boar sperm and further evaluated the effect of this treatment on sperm movement, tyrosine phosphorylation and fertility rate (FR). The sperm fourfold stain technique is accurate (R2 = 0.9356, p > 0.01) for simultaneous evaluation of plasma and acrosomal membrane integrity and mitochondrial membrane potential (IPIAH cells). Centrifugation pre-cryopreservation was not deleterious (p > 0.05) for any analyzed variables. Addition of SP-SRF after cryopreservation was able to improve total and progressive motility (p boar semen was cryopreserved without SP-SRF; however, it was not able to decrease tyrosine phosphorylation (p > 0.05) or improve IPIAH cells (p > 0.05). FR was not (p > 0.05) statistically increased by the addition of seminal plasma, though females inseminated with frozen-thawed boar semen plus SP-SRF did perform better than those inseminated with sperm lacking seminal plasma. Thus, we conclude that sperm fourfold stain can be used to simultaneously evaluate plasma and acrosomal membrane integrity and mitochondrial membrane potential, and the addition of SP-SRF at thawed boar semen cryopreserved in absence of SP-SRF improve its total and progressive motility. PMID:27529819

  2. Mutational Inactivation of a Gene Homologous to Escherichia coli ptsP Affects Poly-β-Hydroxybutyrate Accumulation and Nitrogen Fixation in Azotobacter vinelandii

    OpenAIRE

    Segura, Daniel; Espín, Guadalupe

    1998-01-01

    Strain DS988, an Azotobacter vinelandii mutant with a reduced capacity to accumulate poly-β-hydroxybutyrate, was isolated after mini-Tn5 mutagenesis of the UW136 strain. Cloning and nucleotide sequencing of the affected locus revealed a gene homologous to Escherichia coli ptsP which encodes enzyme INtr, a homologue of enzyme I of the phosphoenol pyruvate-sugar phosphotransferase system with an N-terminal domain similar to the N-terminal domain of some NifA proteins. Strain DS988 was unable to...

  3. Growth, water status and photosynthesis in two maize (zea mays l.) cultivars as affected by supplied nitrogen form and drought stress

    International Nuclear Information System (INIS)

    Hydroponic experiments were conducted to investigate the effects of nitrogen form on plant growth, water status and photosynthetic characteristics under integrated root-zone drought stress (IR-DS) and non drought conditions (non-DS) with two hybrids of maize cultivars Zhengdan 958 (ZD958) and Jundan 20(JD20). On the 12 day of IR-DS, dry matter (DM) of total plant, shoot and root, relative water content (RWC), chlorophyll (Chl.) content, net photosynthetic rate (PN), stomatal conductance (gs), transpiration rate (E) of both cultivars in all N forms treatments as well as intercellular CO/sub 2/ concentration (Ci) except NH/sub 4/-treatment were significantly decreased. However, lower DM production, RWC and PN as well as drought index (DI) were observed for JD20 than ZD958, thereby the later could be considered as a drought tolerance cultivar comparatively. By comparison with sole ammonium (NH/sub 4/)(/sup +/), sole nitrate (NO/sub 3//sup -/) and the mixture of NH/sub 4/sup +/ and NO/sub 3/sup -/ both obviously increased DM of total plant, shoot and root, RWC, PN and Chl. content while decreased gs, E and Ci of both cultivars under drought. The effects of NO/sub 3/ supplied were superior than NH/sub 4/sup +/ NO/sub 3/ supplied in the above responses. These impacts were more predominant in ZD958 than JD20. Further analysis of variation indicated that the impact of N form treatment on most parameters measured except root DM were, in general, less than water regime while higher than cultivar. It is, therefore, concluded that an increase of ratio of NO/sub 3/sup -/ to NH/sub 4/sup +/ in nutrition solution could lead to an enhancement in leaf RWC and photosynthesis of both cultivars subjected to IR-DS, then result in biomass increase, thus alleviate of damage from drought due to their obvious drought-resistance function based on its nutritive role, especially for a drought tolerant cultivar. (author)

  4. ELEVATED CO{sub 2} IN A PROTOTYPE FREE-AIR CO{sub 2} ENRICHMENT FACILITY AFFECTS PHOTOSYNTHETIC NITROGEN RELATIONS IN A MATURING PINE FOREST

    Energy Technology Data Exchange (ETDEWEB)

    ELLSWORTH,D.S.; LA ROCHE,J.; HENDREY,G.R.

    1998-03-01

    A maturing loblolly pine (Pinus taeda L.) forest was exposed to elevated CO{sub 2} in the natural environment in a perturbation study conducted over three seasons using the free-air CO{sub 2} enrichment (FACE) technique. At the time measurements were begun in this study, the pine canopy was comprised entirely of foliage which had developed under elevated CO{sub 2} conditions (atmospheric [CO{sub 2}] {approx} 550 {micro}mol mol{sup {minus}1}). Measurements of leaf photosynthetic responses to CO{sub 2} were taken to examine the effects of elevated CO{sub 2} on photosynthetic N nutrition in a pine canopy under elevated CO{sub 2}. Photosynthetic CO{sub 2} response curves (A-c{sub i} curves) were similar in FACE trees under elevated CO{sub 2} compared with counterpart trees in ambient plots for the first foliage cohort produced in the second season of CO{sub 2} exposure, with changes in curve form detected in the foliage cohorts subsequently produced under elevated CO{sub 2}. Differences in the functional relationship between carboxylation rate and N{sub a} suggest that for a given N{sub a} allocated among successive cohorts of foliage in the upper canopy, V{sub c max} was 17% lower in FACE versus Ambient trees. The authors also found that foliar Rubisco content per unit total protein derived from Western blot analysis was lower in late-season foliage in FACE foliage compared with ambient-grown foliage. The results illustrate a potentially important mode of physiological adjustment to growth conditions that may operate in forest canopies. Their findings suggest that mature loblolly pine trees growing in the field may have the capacity for shifts in intrinsic nitrogen utilization for photosynthesis under elevated CO{sub 2} that are not dependent on changes in leaf N. While carboxylation efficiency per unit N apparently decreased under elevated CO{sub 2}, photosynthetic rates in trees at elevated CO{sub 2} concentrations {approx} 550 pmol mol{sub {minus}1} are still

  5. Elevated CO{sub 2} in a prototype free-air CO{sub 2} enrichment facility affects photosynthetic nitrogen relations in a maturing pine forest

    Energy Technology Data Exchange (ETDEWEB)

    Ellsworth, D.S.; LaRoche, J.; Hendrey, G.R.

    1998-03-01

    A maturing loblolly pine (Pinus taeda L.) forest was exposed to elevated CO{sub 2} in the natural environment in a perturbation study conducted over three seasons using the free-air CO{sub 2} enrichment (FACE) technique. At the time measurements were begun in this study, the pine canopy was comprised entirely of foliage which had developed under elevated CO{sub 2} conditions (atmospheric CO{sub 2} {approx} 550 {micro}mol/mol{sup {minus}1}). Measurements of leaf photosynthetic responses to CO{sub 2} were taken to examine the effects of elevated CO{sub 2} on photosynthetic N nutrition in a pine canopy under elevated CO{sub 2}. Photosynthetic CO{sub 2} response curves (A-c{sub i} curves) were similar in FACE trees under elevated CO{sub 2} compared with counterpart trees in ambient plots for the first foliage cohort produced in the second season of CO{sub 2} exposure, with changes in curve form detected in the foliage cohorts subsequently produced under elevated CO{sub 2}. Differences in the functional relationship between carboxylation rate and N{sub a} suggest that for a given N{sub a} allocated among successive cohorts of foliage in the upper canopy, V{sub c max} was 17% lower in FACE versus Ambient trees. The authors also found that foliar Rubisco content per unit total protein derived from Western blot analysis was lower in late-season foliage in FACE foliage compared with ambient-grown foliage. The results illustrate a potentially important mode of physiological adjustment to growth conditions that may operate in forest canopies. Findings suggest that mature loblolly pine trees growing in the field may have the capacity for shifts in intrinsic nitrogen utilization for photosynthesis under elevated CO{sub 2} that are not dependent on changes in leaf N. Findings suggest a need for continued examination of internal feedbacks at the whole-tree and ecosystem level in forests that may influence long-term photosynthetic responses to elevated CO{sub 2}.

  6. Growth and Phosphorus Uptake of Oat (Arena nuda L.) as Affected by Mineral Nitrogen Forms Supplied in Hydroponics and Soil Culture

    Institute of Scientific and Technical Information of China (English)

    FAN Ming-Shou; LI Zhen; WANG Feng-Mei; ZHANG Jian-Hua

    2009-01-01

    Plants show different growth responses to N sources supplied with either NH4+ or NO3-.The uptake of different N sources also affects the rhizosphere pH and therefore the bioavailability of soil phosphorus,particularly in alkaline soils.The plant growth,P uptake,and P availability in the rhizosphere of oat (Arena nuda L.) grown in hydroponics and in soil culture were investigated under supply with sole NH4+-N,sole NO3--N,or a combination.Sole NO3-fed oat plants accumulated more biomass than sole NH4+-fed ones.The highest biomass accumulation was observed when N was supplied with both NH4+-N and NO3--N.Growth of the plant root increased with the proportion of NO3-in the cultural medium.Better root growth and higher root/shoot ratio were consistently observed in NO3--fed plants.However,root vigor was the highest when N was supplied with NO3-+NH4+.NH4+ supply reduced the rhizosphere pH but did not affect P uptake by plants grown in soils with CaHPO4 added as P source.No P deficiency was observed,and plant P concentrations were generally above 2 g kg-1.P uptake was increased when N was supplied partly or solely as NO3--N,similarly as biomass accumulation.The results suggested that oat was an NO3-prcferring plant,and NO3--N was essential for plant growth and the maintenance of root absorption capacity.N supply with NH4+-N did not improve P nutrition,which was most likely due to the absence of P deficiency.

  7. Shifts in species composition constrain restoration of overgrazed grassland using nitrogen fertilization in Inner Mongolian steppe, China.

    Science.gov (United States)

    Chen, Qing; Hooper, David U; Lin, Shan

    2011-01-01

    Long-term livestock over-grazing causes nitrogen outputs to exceed inputs in Inner Mongolia, suggesting that low levels of nitrogen fertilization could help restore grasslands degraded by overgrazing. However, the effectiveness of such an approach depends on the response of production and species composition to the interactive drivers of nitrogen and water availability. We conducted a five-year experiment manipulating precipitation (NP: natural precipitation and SWP: simulated wet year precipitation) and nitrogen (0, 25 and 50 kg N ha(-1) yr(-1)) addition in Inner Mongolia. We hypothesized that nitrogen fertilization would increase forage production when water availability was relatively high. However, the extent to which nitrogen would co-limit production under average or below average rainfall in these grasslands was unknown.Aboveground net primary production (ANPP) increased in response to nitrogen when precipitation was similar to or higher than the long-term average, but not when precipitation was below average. This shift in limitation was also reflected by water and nitrogen use efficiency. Belowground live biomass significantly increased with increasing water availability, but was not affected by nitrogen addition. Under natural precipitation (NP treatment), the inter-annual variation of ANPP was 3-fold greater than with stable water availability (CV(ANPP) = 61±6% and 17±3% for NP and SWP treatment, respectively) and nitrogen addition increased CV(ANPP) even more (89±14%). This occurred in part because fertilizer nitrogen left in the soil in dry years remained available for uptake during wet years and because of high production by unpalatable annual species in wet years in the NP treatment. In summary, plant growth by residual fertilizer nitrogen could lead to sufficient yields to offset lack of additional production in dry years. However, the utility of fertilization for restoration may be constrained by shifts in species composition and the lack of

  8. Shifts in species composition constrain restoration of overgrazed grassland using nitrogen fertilization in Inner Mongolian steppe, China.

    Directory of Open Access Journals (Sweden)

    Qing Chen

    Full Text Available Long-term livestock over-grazing causes nitrogen outputs to exceed inputs in Inner Mongolia, suggesting that low levels of nitrogen fertilization could help restore grasslands degraded by overgrazing. However, the effectiveness of such an approach depends on the response of production and species composition to the interactive drivers of nitrogen and water availability. We conducted a five-year experiment manipulating precipitation (NP: natural precipitation and SWP: simulated wet year precipitation and nitrogen (0, 25 and 50 kg N ha(-1 yr(-1 addition in Inner Mongolia. We hypothesized that nitrogen fertilization would increase forage production when water availability was relatively high. However, the extent to which nitrogen would co-limit production under average or below average rainfall in these grasslands was unknown.Aboveground net primary production (ANPP increased in response to nitrogen when precipitation was similar to or higher than the long-term average, but not when precipitation was below average. This shift in limitation was also reflected by water and nitrogen use efficiency. Belowground live biomass significantly increased with increasing water availability, but was not affected by nitrogen addition. Under natural precipitation (NP treatment, the inter-annual variation of ANPP was 3-fold greater than with stable water availability (CV(ANPP = 61±6% and 17±3% for NP and SWP treatment, respectively and nitrogen addition increased CV(ANPP even more (89±14%. This occurred in part because fertilizer nitrogen left in the soil in dry years remained available for uptake during wet years and because of high production by unpalatable annual species in wet years in the NP treatment. In summary, plant growth by residual fertilizer nitrogen could lead to sufficient yields to offset lack of additional production in dry years. However, the utility of fertilization for restoration may be constrained by shifts in species composition and

  9. Efficiency of zinc and phosphate fertilizers in maize as affected by direct placement of zinc, phosphorus, nitrogen and copper with seed

    International Nuclear Information System (INIS)

    An investigation was carried out under greenhouse condition on the alluvial soil of Delhi to study the efficiency of Zn and P fertilizers in maize as affected by direct placement of Zn, P, N and Cu with seed. Results indicated that placement of N,P, Zn and Cu directly with seed significantly increased the dry matter yield of plants as compared with control. The utilization of applied P was found to increase significantly at higher levels of N whereas at higher levels of P application the efficiency of fertilizer P utilization by maize was found to be low although in both the cases P derived from fertilizer showed significant increase with increasing levels of N and P. The utilization of fertilizer Zn by plants decreased with increasing levels of Zn applied. Total uptake of Zn by plants showed significant increase due to high levels of N application although Zn derived from fertilizer was found to decrease with increasing levels of N application. The copper content of plants increased due to Cu application. All the P and Zn applied were tagged with 32P and 65Zn respectively. (author)

  10. Factors affecting the corrosion behaviour of aluminium in acid solutions. I. Nitrogen and/or sulphur-containing organic compounds as corrosion inhibitors for Al in HCl solutions

    International Nuclear Information System (INIS)

    Highlights: ► Phenylhydrazine, urea, thiourea, N-allylthiourea, and thiosemicarbazide are good inhibitors for corrosion Al in HCl. ► The additives decrease the rate of corrosion by the adsorption process. ► ΔGads of all used inhibitors reveal strong physisorption process. - Abstract: The corrosion behaviour of Al in 2 M HCl solution in the absence and presence of phenylhydrazine, urea, thiourea, N-allylthiourea, and thiosemicarbazide is investigated using different chemical and electrochemical techniques. The inhibition efficiencies of these compounds increase with increasing their concentration and molecular weights. The inhibitive action of these compounds is discussed in terms of blocking the electrode surface by adsorption of the inhibitor molecules according to Langmuir isotherm. The thermodynamic parameters Kads and ΔGads° are calculated and discussed. The values of ΔGads° reveal strong physisorption of the inhibitors on the metal surface.

  11. Transcriptome response to nitrogen starvation in rice

    Indian Academy of Sciences (India)

    Hongmei Cai; Yongen Lu; Weibo Xie; Tong Zhu; Xingming Lian

    2012-09-01

    Nitrogen is an essential mineral nutrient required for plant growth and development. Insufficient nitrogen (N) supply triggers extensive physiological and biochemical changes in plants. In this study, we used Affymetrix GeneChip rice genome arrays to analyse the dynamics of rice transcriptome under N starvation. N starvation induced or suppressed transcription of 3518 genes, representing 10.88% of the genome. These changes, mostly transient, affected various cellular metabolic pathways, including stress response, primary and secondary metabolism, molecular transport, regulatory process and organismal development. 462 or 13.1% transcripts for N starvation expressed similarly in root and shoot. Comparative analysis between rice and Arabidopsis identified 73 orthologous groups that responded to N starvation, demonstrated the existence of conserved N stress coupling mechanism among plants. Additional analysis of transcription profiles of microRNAs revealed differential expression of miR399 and miR530 under N starvation, suggesting their potential roles in plant nutrient homeostasis.

  12. Boron and nitrogen impurities in SiC nanoribbons: an ab initio investigation.

    Science.gov (United States)

    Costa, C D; Morbec, J M

    2011-05-25

    Using ab initio calculations based on density-functional theory we have performed a theoretical investigation of substitutional boron and nitrogen impurities in silicon carbide (SiC) nanoribbons. We have considered hydrogen terminated SiC ribbons with zigzag and armchair edges. In both systems we verify that the boron and nitrogen atoms energetically prefer to be localized at the edges of the nanoribbons. However, while boron preferentially substitutes a silicon atom, nitrogen prefers to occupy a carbon site. In addition, our electronic-structure calculations indicate that (i) substitutional boron and nitrogen impurities do not affect the semiconducting character of the armchair SiC nanoribbons, and (ii) the half-metallic behavior of the zigzag nanoribbons is maintained in the presence of substitutional boron impurities. In contrast, nitrogen atoms occupying edge carbon sites transform half-metallic zigzag nanoribbons into metallic systems. PMID:21540516

  13. The Effect of Nitrogen Enrichment on C1-Cycling Microorganisms and Methane Flux in Salt Marsh Sediments

    OpenAIRE

    Irvine, Irina C.; Vivanco, Lucía; Peris N. Bentley; Martiny, Jennifer B. H.

    2012-01-01

    Methane (CH4) flux from ecosystems is driven by C1-cycling microorganisms – the methanogens and the methylotrophs. Little is understood about what regulates these communities, complicating predictions about how global change drivers such as nitrogen enrichment will affect methane cycling. Using a nitrogen addition gradient experiment in three Southern California salt marshes, we show that sediment CH4 flux increased linearly with increasing nitrogen addition (1.23 μg CH4 m−2 day−1 for each g ...

  14. Reliable reference genes for normalization of gene expression in cucumber grown under different nitrogen nutrition.

    Directory of Open Access Journals (Sweden)

    Anna Warzybok

    Full Text Available In plants, nitrogen is the most important nutritional factor limiting the yield of cultivated crops. Since nitrogen is essential for synthesis of nucleotides, amino acids and proteins, studies on gene expression in plants cultivated under different nitrogen availability require particularly careful selection of suitable reference genes which are not affected by nitrogen limitation. Therefore, the objective of this study was to select the most reliable reference genes for qPCR analysis of target cucumber genes under varying nitrogen source and availability. Among twelve candidate cucumber genes used in this study, five are highly homologous to the commonly used internal controls, whereas seven novel candidates were previously identified through the query of the cucumber genome. The expression of putative reference genes and the target CsNRT1.1 gene was analyzed in roots, stems and leaves of cucumbers grown under nitrogen deprivation, varying nitrate availability or different sources of nitrogen (glutamate, glutamine or NH3. The stability of candidate genes expression significantly varied depending on the tissue type and nitrogen supply. However, in most of the outputs genes encoding CACS, TIP41, F-box protein and EFα proved to be the most suitable for normalization of CsNRT1.1 expression. In addition, our results suggest the inclusion of 3 or 4 references to obtain highly reliable results of target genes expression in all cucumber organs under nitrogen-related stress.

  15. Nitrogen species

    Science.gov (United States)

    Harries, J. E.; Brasseur, G.; Coffey, M. T.; Fischer, H.; Gille, J.; Jones, R.; Louisnard, N.; McCormick, M. P.; Noxon, J.; Owens, A. J.

    Total odd nitrogen, NO(y), may be defined as the sum of all active nitrogen species that interchange photochemically with one another on a time scale of the order of weeks or less. As noted, NO + NO2 reactions dominate the processes controlling the ozone balance in the contemporary stratosphere. The observational data from non-satellite platforms are reviewed. The growth in available satellite data in the past four years is considered. Some of the most important scientific issues are discussed, taking into account new results from atmospheric models (mainly 2-D). The model results are compared with the observational data.

  16. Influence of natural zeolite and nitrification inhibitor on organics degradation and nitrogen transformation during sludge composting.

    Science.gov (United States)

    Zhang, Junya; Sui, Qianwen; Li, Kun; Chen, Meixue; Tong, Juan; Qi, Lu; Wei, Yuansong

    2016-01-01

    Sludge composting is one of the most widely used treatments for sewage sludge resource utilization. Natural zeolite and nitrification inhibitor (NI) are widely used during composting and land application for nitrogen conservation, respectively. Three composting reactors (A--the control, B--natural zeolite addition, and C--3,4-dimethylpyrazole phosphate (DMPP) addition) were established to investigate the influence of NI and natural zeolite addition on organics degradation and nitrogen transformation during sludge composting conducted at the lab scale. The results showed that, in comparison with the control, natural zeolite addition accelerated organics degradation and the maturity of sludge compost was higher, while the DMPP addition slowed down the degradation of organic matters. Meanwhile, the nitrogen transformation functional genes including those responses for nitrification (amoA and nxrA) and denitrification (narG, nirS, nirK, and nosZ) were quantified through quantitative PCR (qPCR) to investigate the effects of natural zeolites and DMPP addition on nitrogen transformation. Although no significant difference in the abundance of nitrogen transformation functional genes was observed between treatments, addition of both natural zeolite and DMPP increases the final total nitrogen content by 48.6% and 23.1%, respectively. The ability of natural zeolite for nitrogen conservation was due to the absorption of NH3 by compost, and nitrogen conservation by DMPP was achieved by the source reduction of denitrification. Besides, it was assumed that the addition of natural zeolite and DMPP may affect the activity of these genes instead of the abundance. PMID:26358216

  17. Increased rainfall variability and N addition accelerate litter decomposition in a restored prairie.

    Science.gov (United States)

    Schuster, Michael J

    2016-03-01

    Anthropogenic nitrogen deposition and projected increases in rainfall variability (the frequency of drought and heavy rainfall events) are expected to strongly influence ecosystem processes such as litter decomposition. However, how these two global change factors interact to influence litter decomposition is largely unknown. I examined how increased rainfall variability and nitrogen addition affected mass and nitrogen loss of litter from two tallgrass prairie species, Schizachyrium scoparium and Solidago canadensis, and isolated the effects of each during plant growth and during litter decomposition. I increased rainfall variability by consolidating ambient rainfall into larger events and simulated chronic nitrogen deposition using a slow-release urea fertilizer. S. scoparium litter decay was more strongly regulated by the treatments applied during plant growth than by those applied during decomposition. During plant growth, increased rainfall variability resulted in S. scoparium litter that subsequently decomposed more slowly and immobilized more nitrogen than litter grown under ambient conditions, whereas nitrogen addition during plant growth accelerated subsequent mass loss of S. scoparium litter. In contrast, S. canadensis litter mass and N losses were enhanced under either N addition or increased rainfall variability both during plant growth and during decomposition. These results suggest that ongoing changes in rainfall variability and nitrogen availability are accelerating nutrient cycling in tallgrass prairies through their combined effects on litter quality, environmental conditions, and plant community composition. PMID:26216200

  18. The Effect of Nitrogen Enrichment on C1-Cycling Microorganisms and Methane Flux in Salt Marsh Sediments

    Directory of Open Access Journals (Sweden)

    Irina Catherine Irvine

    2012-03-01

    Full Text Available Methane (CH4 flux from ecosystems is driven by C1-cycling microorganisms – the methanogens and the methylotrophs. Little is understood about what regulates these communities, complicating predictions about how global change drivers such as nitrogen enrichment will affect methane cycling. Using a nitrogen addition gradient experiment in three Southern California salt marshes, we show that sediment CH4 flux increased linearly with increasing nitrogen addition (1.23 µg CH4 m-2 d-1 for each g N m-2 yr-1 applied after seven months of fertilization. To test the reason behind this increased CH4 flux, we conducted a microcosm experiment altering both nitrogen and carbon availability under aerobic and anaerobic conditions. Methanogenesis appeared to be both nitrogen and carbon (acetate limited. N and C each increased methanogenesis by 18%, and together by 44%. In contrast, methanotrophy was stimulated by carbon (methane addition (830%, but was unchanged by nitrogen addition. Sequence analysis of the sediment methylotroph community with the methanol dehydrogenase gene (mxaF revealed three distinct clades that fall outside of known lineages. However, in agreement with the microcosm results, methylotroph abundance (assayed by qPCR and composition (assayed by T-RFLP did not vary across the experimental nitrogen gradient in the field. Together, these results suggest that nitrogen enrichment to salt marsh sediments increases methane flux by stimulating the methanogen community.

  19. Dual purpose wheat production with different levels of nitrogen topdressing

    Directory of Open Access Journals (Sweden)

    Éderson Luis Henz

    2016-04-01

    Full Text Available Currently, the practice of Crop-Livestock Integration is stimulated as a way of increasing the generation of foreign exchange for Brazil. Integrated systems improve land use efficiency as well as preserve, recover and increment or soil fertility. The aim of this research was to evaluate how different doses of nitrogen fertilization can affect production and quality of dual purpose wheat submitted to grazing. The experimental designed was randomized block with five treatments (0, 75, 150, 225 and 300 Kg N ha-1, like ammonium nitrate and four repetitions. The forage yield, the percentage crude protein (P=.0001 and acid detergent insoluble protein (P=.0054 had a linear increased because of the nitrogen addition doses. The crude protein percentage changed the estimate of all soluble carbohydrates (P=.0001 and non-fibrous carbohydrates (P=.0186, but did not influence the, nitrogen detergent fiber corrected with ash and proteins percentage contributing for content cell. The crops production (P=.0001 and the number of kernels per ear (P=.0001 showed significantly difference because of the nitrogen additions dose, increasing the number of fertile flowers. The nitrogen topdressing alters forage production, the chemical composition and the production of dual purpose wheat grains subjected to grazing.

  20. Transport and Fate of Organic and Inorganic Nitrogen from Biosolids leachates

    Science.gov (United States)

    Ilani, Talli; Trifonov, Pavel; Arye, Gilboa

    2014-05-01

    The use of biosolids as a means to ameliorate soil becomes prevalent in the last few years. In agricultural fields, the application of biosolids will be followed by irrigation; resulting in excessive leaching of the dissolved fraction of the organic matter. The dissolved organic matter (DOM) is one of the major players in the chemical, physical and biological processes in soils. The DOM mainly composed of dissolved organic carbon (DOC) and lower proportions of dissolved organic nitrogen (DON) and phosphate (DOP). The DON is considered to be the primary source of mineralisable nitrogen in the soil and can be used as an estimate of the nitrogen supplying capacity of the organic matter. Most of the researches which are dealing with nitrogen fate in terrestrial environments focused on its inorganic fractions (mainly nitrate and ammonium) and their transport toward the dipper soil layers. Since DON can be the source of the inorganic nitrogen (by providing nutrients and energy to nitrifying microbes, which in turn increases the nitrogen source for plants as nitrate), knowledge about the nature of its transport characteristics in the soil is important in the case of biosolids amendment. In addition, irrigation water quality (e.g. fresh water, wastewater or desalinized water) may significantly affect the transport and fate of the various nitrogen forms. The main objective of this study is to examine the fate and co-transport of organic and inorganics nitrogen, originating from biosolids leachates in the subsoil. The effect of water quality and flow rate under saturated steady-state flow is examined by a series of flow-through soil column experiments. The established breakthrough curves of the co-transport of total nitrogen, organic nitrogen (will be calculated from the differences between the total nitrogen measurements and the inorganic nitrogen measurements), nitrate, ammonium, dissolved organic carbon and chloride is presented and discussed.

  1. Interactive Effects of Nitrogen and Climate Change on Biodiversity

    Science.gov (United States)

    Porter, E. M.; Bowman, W. D.; Clark, C. M.; Compton, J. E.; Pardo, L. H.; Soong, J.

    2011-12-01

    Biodiversity has been described as the diversity of life on earth within species, between species and in ecosystems. Biodiversity contributes to regulating ecosystem services like climate, flood, disease, and water quality regulation. Biodiversity also supports and sustains ecosystem services that provide material goods like food, fiber, fuel, timber and water, and to non-material benefits like educational, recreational, spiritual, and aesthetic ecosystem services. The Millennium Ecosystem Assessment estimated that the rate of biodiversity loss due to human activity in the last 50 years has been more rapid than at any other time in human history, and that many of the drivers of biodiversity loss are increasing. The strongest drivers of biodiversity loss include habitat loss, overexploitation, invasive species, climate change, and pollution, including pollution from reactive nitrogen. Of these stressors, climate change and reactive nitrogen from anthropogenic activities are causing some of the most rapid changes. Climate change is causing warming trends that result in consistent patterns of poleward and elevational range shifts of flora and fauna, causing changes in biodiversity. Warming has also resulted in changes in phenology, particularly the earlier onset of spring events, migration, and lengthening of the growing season, disrupting predator-prey and plant-pollinator interactions. In addition to warming, elevated carbon dioxide by itself can affect biodiversity by influencing plant growth, soil water, tissue stoichiometry, and trophic interactions. Nitrogen enrichment also impacts ecosystems and biodiversity in a variety of ways. Nitrogen enhances plant growth, but has been shown to favor invasive, fast-growing species over native species adapted to low nitrogen conditions. Although there have been a limited number of empirical studies on climate change and nitrogen interactions, inferences can be drawn from observed responses to each stressor by itself. For

  2. Quantifying atmospheric nitrogen outflow from the Front Range of Colorado

    Science.gov (United States)

    Neuman, J. A.; Eilerman, S. J.; Brock, C. A.; Brown, S. S.; Dube, W. P.; Herndon, S. C.; Holloway, J. S.; Nowak, J. B.; Roscioli, J. R.; Ryerson, T. B.; Sjostedt, S. J.; Thompson, C. R.; Trainer, M.; Veres, P. R.; Wild, R. J.

    2015-12-01

    Reactive nitrogen emitted to the atmosphere from urban, industrial, and agricultural sources can be transported and deposited far from the source regions, affecting vegetation, soils, and water of sensitive ecosystems. Mitigation of atmospheric nitrogen deposition requires emissions characterization and quantification. Ammonia (NH3), a full suite of gas-phase oxidized nitrogen compounds, and particulate matter were measured from an aircraft that flew downwind from concentrated animal feeding operations, oil and gas extraction facilities, and urban areas along the Colorado Front Range in March and April 2015, as part of the Shale Oil and Natural Gas Nexus (SONGNEX) field study. Additionally, NH3 measurements from a fully instrumented aircraft that flew over the same region in July and August 2014 as part of the Front Range Air Pollution and Photochemistry Experiment (FRAPPE) are used to examine atmospheric nitrogen emission and transport. Cross-wind plume transects and altitude profiles were performed over the source regions and 60-240 km downwind. Plumes were transported in the boundary layer with large NH3 mixing ratios (typically 20-100 ppbv) and were tens of km wide. The NH3 in these plumes provided an atmospheric nitrogen burden greater than 0.2 kg N/ha. Nitrogen oxides and their oxidation products and particulate matter were also enhanced in the plumes, but with concentrations substantially less than NH3. With efficient transport followed by wet deposition, these plumes have the potential to provide a large nitrogen input to the neighboring Rocky Mountain National Park, where nitrogen deposition currently exceeds the ecological critical load of 1.5 kg N/ha/yr.

  3. Nitrogen tank

    CERN Multimedia

    2006-01-01

    Wanted The technical file about the pressure vessel RP-270 It concerns the Nitrogen tank, 60m3, 22 bars, built in 1979, and installed at Point-2 for the former L3 experiment. If you are in possession of this file, or have any files about an equivalent tank (probably between registered No. RP-260 and -272), please contact Marc Tavlet, the ALICE Glimos.

  4. Efficient Management of Nitrogen Fertilizers for Flooded Rice in Relation to Nitrogen Transformations in Flooded Soils

    Institute of Scientific and Technical Information of China (English)

    ZHUZHAO-LIANG

    1992-01-01

    Recent progresses in efficient management of nitrogen fertilizers for flooded rice in relation to nitrogen transformations in flooded soil were reviewed.Considerable progress has been achieved in the investigation on the mechanism of ammonia loss and the factors affecting it .However,little progress has been obtained in the investigations on nitrification-denitrification loss owing to the lack of method for estimating the fluxes of gaseous N products.Thus,so far the management practices developed or under investigation primarily for reducing ammonia loss are feasible or promising,while those for reducing nitrification-denitrification loss seem obscure,except the point deep placement. In addition,it was emphasized that the prediction of soil N supply and the recommendation of the optimal rate of N application based on it are only semi-quantitative.The priorities in research for improving the prediction are indicated.

  5. The effect of atmospheric nitrogen deposition on marine nitrogen cycling throughout the global ocean

    Science.gov (United States)

    Somes, Christopher; Oschlies, Andreas

    2014-05-01

    The rapidly increasing rate of anthropogenic nitrogen deposition has the potential to perturb marine ecosystems and biogeochemical cycles because nitrogen is one of the major limiting nutrients in the ocean. We use an Earth System Climate Model that includes ocean biogeochemistry to assess the impact of atmospheric nitrogen deposition. Experiments are conducted where we artificially add nitrogen to nearly all locations individually throughout the global surface ocean using a nitrogen deposition rate of 700 mg N m-2 yr-1, which is consistent with modern estimates near industrial areas. We identify oceanic "biomes" that respond differently to atmospheric nitrogen deposition. (1) When nitrogen is deposited near oxygen minimum zones where water column denitrification occurs, locally increased primary production stimulates additional denitrification. Since water column denitrification removes 7 mol N for every mol N of newly formed organic matter respired, the global oceanic nitrogen inventory declines in response to nitrogen deposition in these areas. This slow, but steady decline persists for at least 1,000 years. (2) When nitrogen is deposited above shallow continental shelves where benthic denitrification occurs, our benthic denitrification model predicts an increase that is nearly equal to the nitrogen deposited and thus no net change in the global nitrogen inventory. (3) When nitrogen is deposited into the high latitude open ocean far removed from nitrogen fixation and denitrification, all of this deposited nitrogen initially accumulates in the ocean. This nitrogen eventually circulates into the tropical oxygen minimum zones where it fuels additional primary production and denitrification, which removes nitrogen at a rate equal to the deposition after 1,000 years and leads to a stable, but increased nitrogen inventory in our model. (4) When nitrogen is deposited into the open ocean where nitrogen fixation occurs, nitrogen fixation decreases due to less nitrogen

  6. Food additives

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/002435.htm Food additives To use the sharing features on this page, please enable JavaScript. Food additives are substances that become part of a food ...

  7. Effects of nitrogen application rates on nitrogen uptake and utilization by sugarcane

    International Nuclear Information System (INIS)

    A pot experiment was conducted under greenhouse conditions to evaluate of nitrogen application rates (three nitrogen rates treatments of 15N-labeled urea 2.5, 5.0 and 7.5 g/pot, equal to 225, 450 and 675 kg/hm2, respectively) on nitrogen uptake and utilization of the sugarcane cultivar ROC22. Results showed that the nitrogen accumulation of 17.27% ∼ 27.28% in sugarcane was derived from urea, and that of 72.72% ∼ 82.73% was from soil and seed-stem. Meanwhile, the nitrogen utilization ratio by sugarcane was 34.21% to 42.46%. In addition, with the enhancement of nitrogen application rates, the accumulation of dry matter and nitrogen significantly as well as the proportion of N from nitrogen fertilizer in sugarcane plant, and the nitrogen utilization by leaves showed an ascending trend, while nitrogen utilization ratio by sugarcane decreased significantly and the nitrogen utilization by stalk displayed a dropping trend. The results also indicated that the alkali hydrolysis nitrogen and nitrate nitrogen content in soil increased when the nitrogen application rates went up, and the accumulation at the soil layer of 0 ∼ 20 cm in both was dramatically larger than that of 20 ∼ 40 cm. In the present study, the suitable amount and location of nitrogen fertilizer applied were urea 5.0 g/pot (equal to 450 kg/hm2) and 20 cm soil depth. (authors)

  8. Effect of Nitrogen Supply on the Nitrogen Use Efficiency of an Annual Herb, Helianthus annuus L.

    Institute of Scientific and Technical Information of China (English)

    Zhi-You YUAN; Ling-Hao LI; Jian-Hui HUANG; Xing-Guo HAN; Shi-Qiang WAN

    2005-01-01

    Nitrogen use efficiency (NUE) is the product of nitrogen productivity (NP) and the mean residence time of nitrogen (MRT). Theory suggests that there should be a trade-off between both components,but direct experimental evidence is still scarce. To test this hypothesis, we analyzed the effect of varying nitrogen supply levels on NUEand its two components (NP, MRT) in Helianthus annuus L., an annual herb.The plants investigated were subjected to six nitrogen levels (0, 2, 4, 8, 16, and 32 g N/m2). Total plant production increased substantially with increasing nitrogen supply. Nitrogen uptake and loss also in creased with nitrogen supply. Nitrogen influx (rin) and outflux (rout) were defined as the rates of nitrogen uptake and loss per unit aboveground nitrogen, respectively. Both rin and rout increased with increasing nitrogen supply. In addition, rin was far higher than rout. Consequently, the relative rate of nitrogen incre ment (rin- rout) also increased with nitrogen supply. There were marked differences between treatments with respect to parameters related to the stress resistance syndrome: nitrogen pool size, leaf nitrogen concentration,and net aboveground productivity increased with nitrogen supply. Plants at high nitrogen levels showed a higher NP (the growth rate per unit aboveground nitrogen) and a shorter MRT (the inverse of rout), whereas plants at low nitrogen levels displayed the reverse pattern. Shorter MRT for plants at high nitrogen levels was caused by the abscission of leaves that contained relatively large fractions of total plant nitrogen. We found a negative relationship between NP and MRT, the components of NUE, along the gradient of nitrogen availability, suggesting that there was a trade-off between NP and MRT. The NUE increased with increasing nitrogen availability, up to a certain level, and then decreased. These results offer support for the hypoth esis that adaptation to infertile habitats involves a low nitrogen loss (long MRT in the

  9. Experimental and numerical investigations on nitrogen species transport in unsaturated soil during various irrigation patterns

    Indian Academy of Sciences (India)

    M Berlin; Indumathi M Nambi; G Suresh Kumar

    2015-12-01

    The transport of nitrogen coming from wastewater applied agricultural field is a major problem in assessing the vulnerability of groundwater contamination. In this study, laboratory column experiments are conducted in order to simulate the paddy, groundnut and wheat irrigation with wastewater. The experiments are carried out with high clay content (≈35%) soil from Kancheepuram, Tamilnadu and low clay (≈9%) soil from Ludhiana, Punjab, India. Furthermore, a numerical model and HYDRUS-1D model are developed to simulate the experimental results. The experimental results show that there is no effluent collected at the bottom of the column during groundnut irrigation in Kancheepuram soil and effluent collected except during first irrigation in the case of wheat irrigation in Ludhiana soil. The experimental and numerical results illustrate that when 50 mg/l of ammonium and 20 mg/l of nitrate nitrogen applied during paddy irrigation, the peak nitrate nitrogen concentration of 50 mg/l is arrived after 10 days in Kancheepuram soil due to low permeability and relatively less background soil nitrogen. But in the case of Ludhiana soil with 94 mg/l of total nitrogen applied during paddy irrigation, the peak nitrate nitrogen concentration of 1,620 mg/l is observed at first day due to high permeability and high soil background nitrogen concentration. Additionally, the model results show that the application of high nitrogen content wastewater for irrigation in Ludhiana soil will affect the groundwater quality even when the groundwater table is deep as compared with Kancheepuram soil.

  10. Preprototype nitrogen supply subsystem development

    Science.gov (United States)

    Heppner, D. B.; Fort, J. H.; Schubert, F. H.

    1982-01-01

    The design and development of a test stand for the Nitrogen Generation Module (NGM) and a series of tests which verified its operation and performance capability are described. Over 900 hours of parametric testing were achieved. The results from this testing were then used to design an advanced NGM and a self contained, preprototype Nitrogen Supply Subsystem. The NGM consists of three major components: nitrogen generation module, pressure controller and hydrazine storage tank and ancillary components. The most important improvement is the elimination of all sealing surfaces, achieved with a total welded or brazed construction. Additionally, performance was improved by increasing hydrogen separating capability by 20% with no increase in overall packaging size.

  11. Nutritional quality improvement of ''tape ketela'', an Indonesian traditional fermented cassava: Increase of its protein content through gamma irradiation of the yeasts in ''ragi tape'' and addition of nitrogen sources

    International Nuclear Information System (INIS)

    The molds used in this study were Rhizopus sp. and Mucor sp., while the yeasts used were C. utilis, C. solani, S. cerevisiae and Endomycopsis sp. Gamma irradiation (60Co) was conducted to C. utilis and C. solani, at doses of 0, 10, 20, 30 and 40 krad with irradiation rate of 61.64174 krad/hour. Molds were irradiated using ultraviolet light. As the mineral and nitrogen sources for the microorganisms, (NH4)2SO4, (NH4)2HPO4 and MgSO4.7H2O were used in the form of solution to soak peeled cassava tubers before being fermented. Growth stimulation effect for the yeasts was observed from treatment of gamma irradiation at dose of 10 krad. ''Ragi tape'' prepared using these yeasts and non-UV-irradiated molds in combination with the utilization of mineral (nitrogen) sources, significantly increased the protein content of ''tape ketela''. The ''tape ketela'' obtained using those treatments had a protein content of 6.43% (dry basis) compared to 2.91% (db) for the control. However, it had a lower reducing sugar content, i.e. 11.43% (db) compared to 31.76% for the control. The viability of the yeasts and molds in ''ragi tape'' during storage in a refrigerator as well as at room temperature is found good until four weeks of storage. (author). 11 refs, 2 figs, 3 tabs

  12. Yield and postharvest quality of winter growing crisphead lettuce as affected by doses of nitrogen and molybdenum Rendimento e qualidade pós-colheita de alface americana em função de doses de nitrogênio e molibdênio

    OpenAIRE

    Geraldo M de Resende; Marco Antônio R Alvarenga; Jony E Yuri; Rovilson José de Souza

    2010-01-01

    The trial was carried out at Três Pontas, Minas Gerais State, Brazil, from April to July 2003, to evaluate the influence of nitrogen and molybdenum rates on productive characteristics and postharvest quality of crisphead lettuce (Lactuca sativa L.). A randomized complete block design with three replications was used. Treatments were a factorial combination of four nitrogen rates (0.0; 60.0; 120.0 and 180.0 kg ha-1) applied in additional the dose commonly used by growers (60 kg ha-1 of N) and ...

  13. Application of a Chemiluminescence Detector for the Measurement of Total Oxides of Nitrogen and Ammonia in the Atmosphere

    Science.gov (United States)

    Hodgeson, J. A.; Bell, J. P.; Rehme, K. A.; Krost, K. J.; Stevens, R. K.

    1971-01-01

    By means of the thermal conversion of nitrogen dioxide to the nitric oxide, the chemiluminescent nitric oxide monitor, based on the nitric oxide plus ozone reaction, may be used for monitoring nitrogen dioxide plus nitric oxide (NO(x)). Under conditions previously described, ammonia is also converted to nitric oxide and therefore interferes. A metal surface, gold wool or stainless steel, operated at two different temperatures has been used to convert only nitrogen dioxide or nitrogen dioxide plus ammonia. Quantitative conversion of nitrogen dioxide to nitric oxide has been obtained at temperatures as low as 200 C. Conversion of ammonia is effected at temperatures of 300 C or higher. By the addition of a converter the basic nitric oxide monitor may be used for measuring NO(x) or NO(x) plus ammonia. As an alternate mode, for a fixed high temperature, a specific scrubber is described for removing NH3 without affecting NO2 concentrations.

  14. PRODUCTION OF EMISSIONS DURING COMBUSTION OF DENDROMASS WITH DIFFERENT TYPES OF ADDITIVES

    OpenAIRE

    Jandačka, Jozef; Holubčik, Michal; Malcho, Milan

    2015-01-01

    Dendromass remains the largest biomass energy source today. Dendromass has a lot of advantages in comparison with fossil fuels. One important benefit is reduced SO2 and NOx formation through a decrease in fuel bound sulfur and nitrogen respectively. One of applications of dendromass are wood pellets. Using of additives can affect some properties of wood pellets include combustion and production of emissions. In this work were produced wood pellets with additives (kaolin, talc, lime, limestone...

  15. An analytical study of nitrogen oxides and carbon monoxide emissions in hydrocarbon combustion with added nitrogen - Preliminary results

    Science.gov (United States)

    Bittker, D. A.

    1980-01-01

    The influence of ground-based gas turbine combustor operating conditions and fuel-bound nitrogen (FBN) found in coal-derived liquid fuels on the formation of nitrogen oxides and carbon monoxide is investigated. Analytical predictions of NOx and CO concentrations are obtained for a two-stage, adiabatic, perfectly-stirred reactor operating on a propane-air mixture, with primary equivalence ratios from 0.5 to 1.7, secondary equivalence ratios of 0.5 or 0.7, primary stage residence times from 12 to 20 msec, secondary stage residence times of 1, 2 and 3 msec and fuel nitrogen contents of 0.5, 1.0 and 2.0 wt %. Minimum nitrogen oxide but maximum carbon monoxide formation is obtained at primary zone equivalence ratios between 1.4 and 1.5, with percentage conversion of FBN to NOx decreasing with increased fuel nitrogen content. Additional secondary dilution is observed to reduce final pollutant concentrations, with NOx concentration independent of secondary residence time and CO decreasing with secondary residence time; primary zone residence time is not observed to affect final NOx and CO concentrations significantly. Finally, comparison of computed results with experimental values shows a good semiquantitative agreement.

  16. Estimating Canopy Nitrogen Concentration in Sugarcane Using Field Imaging Spectroscopy

    Directory of Open Access Journals (Sweden)

    Marc Souris

    2012-06-01

    Full Text Available The retrieval of nutrient concentration in sugarcane through hyperspectral remote sensing is widely known to be affected by canopy architecture. The goal of this research was to develop an estimation model that could explain the nitrogen variations in sugarcane with combined cultivars. Reflectance spectra were measured over the sugarcane canopy using a field spectroradiometer. The models were calibrated by a vegetation index and multiple linear regression. The original reflectance was transformed into a First-Derivative Spectrum (FDS and two absorption features. The results indicated that the sensitive spectral wavelengths for quantifying nitrogen content existed mainly in the visible, red edge and far near-infrared regions of the electromagnetic spectrum. Normalized Differential Index (NDI based on FDS(750/700 and Ratio Spectral Index (RVI based on FDS(724/700 are best suited for characterizing the nitrogen concentration. The modified estimation model, generated by the Stepwise Multiple Linear Regression (SMLR technique from FDS centered at 410, 426, 720, 754, and 1,216 nm, yielded the highest correlation coefficient value of 0.86 and Root Mean Square Error of the Estimate (RMSE value of 0.033%N (n = 90 with nitrogen concentration in sugarcane. The results of this research demonstrated that the estimation model developed by SMLR yielded a higher correlation coefficient with nitrogen content than the model computed by narrow vegetation indices. The strong correlation between measured and estimated nitrogen concentration indicated that the methods proposed in this study could be used for the reliable diagnosis of nitrogen quantity in sugarcane. Finally, the success of the field spectroscopy used for estimating the nutrient quality of sugarcane allowed an additional experiment using the polar orbiting hyperspectral data for the timely determination of crop nutrient status in rangelands without any requirement of prior

  17. Development of photosynthetic activity in Porphyridium purpureum (Rhodophyta) following nitrogen starvation

    Energy Technology Data Exchange (ETDEWEB)

    Levy, I.; Gantt, E. (Smithsonian Institution, Washington, DC (USA))

    1990-03-01

    The effects of nitrogen limitation on laboratory cultures of Porphyridium purpureum Bory, Drew and Ross were studied under continuous white light illumination (35 {mu}E {times} m{sup {minus}2} {times} s{sup {minus}1}). Growth ceased, respiration exceeded photosynthesis, chlorophyll content was reduced by 80%, and phycoerythrin content was reduced by 99% over a period of 14 days under nitrogen limitation. Recovery upon addition of nitrogen resulted in increased phycobiliprotein content, appearance of phycobilisomes attached to the thylakoids, increased oxygen evolution, and increased fluorescence emission from photosystem 1 (720 nm) and photosystem 2 (685 nm) upon excitation by green light. Growth resumes after 72 h and was concomitant with an increase of chlorophyll, phycoerythrin and phycobilisomes per thylakoid area. The results suggest that photosystem 1 was less affected by nitrogen starvation than photosystem 2 and that the recovery was largely dependent on the restoration of phycobilisomes and other photosystem components.

  18. Nutrient contents and production of rocket as affected by nitrogen concentrations in the nutritive solution Teores de nutrientes e produção de rúcula em função das concentrações de nitrogênio em solução nutritiva

    OpenAIRE

    Rodrigo Luiz Cavarianni; Arthur Bernardes Cecílio Filho; Jairo Osvaldo Cazetta; André May; Mariana Marotti Corradi

    2008-01-01

    Empiricism in the use of nutrient solutions is frequent. Several times the same nutrient solution is used to grow different species based only on morphological similarities. This practice may lead to nutritional imbalances, affecting not only the production but also the quality of the product due to an accumulation of nitrate. An experiment under hydroponic conditions - the NFT system - was conducted with the aim of evaluating the effect of the concentration of nitrogen in the nutrient soluti...

  19. Reactive nitrogen deposition to South East Asian rainforest

    Science.gov (United States)

    di Marco, Chiara F.; Phillips, Gavin J.; Thomas, Rick; Tang, Sim; Nemitz, Eiko; Sutton, Mark A.; Fowler, David; Lim, Sei F.

    2010-05-01

    The supply of reactive nitrogen (N) to global terrestrial ecosystems has doubled since the 1960s as a consequence of human activities, such as fertilizer application and production of nitrogen oxides by fossil-fuel burning. The deposition of atmospheric N species constitutes a major nutrient input to the biosphere. Tropical forests have been undergoing a radical land use change by increasing cultivation of sugar cane and oil palms and the remaining forests are increasingly affected by anthropogenic activities. Yet, quantifications of atmospheric nitrogen deposition to tropical forests, and nitrogen cycling under near-pristine and polluted conditions are rare. The OP3 project ("Oxidant and Particle Photochemical Processes above a Southeast Asian Tropical Rainforest") was conceived to study how emissions of reactive trace gases from a tropical rain forest mediate the regional scale production and processing of oxidants and particles, and to better understand the impact of these processes on local, regional and global scale atmospheric composition, chemistry and climate. As part of this study we have measured reactive, nitrogen containing trace gas (ammonia, nitric acid) and the associated aerosol components (ammonium, nitrate) at monthly time resolution using a simple filter / denuder for 16 months. These measurements were made at the Bukit Atur Global Atmospheric Watch tower near Danum Valley in the Malaysian state of Sabah, Borneo. In addition, the same compounds were measured at hourly time-resolution during an intensive measurement period, with a combination of a wet-chemistry system based on denuders and steam jet aerosol collectors and an aerosol mass spectrometer (HR-ToF-AMS), providing additional information on the temporal controls. During this period, concentrations and fluxes of NO, NO2 and N2O were also measured. The measurements are used for inferential dry deposition modelling and combined with wet deposition data from the South East Asian Acid

  20. Response of N2 O Fluxes to the Addition of Nitrogen and Phosphorous in a Southern Subtropical Fir Forest%南方亚热带杉木林土壤 N2O排放对氮磷添加的响应

    Institute of Scientific and Technical Information of China (English)

    孙凡; 张磊

    2015-01-01

    利用国际森林土壤温室气体采集、分析最普遍的方法———静态箱法和气相色谱法,对石溪林场杉木林土壤主要温室气体的排放和吸收通量进行了研究.探讨氮磷添加后土壤主要温室气体的响应规律,以及对森林温室气体通量的影响.研究表明,高氮及高氮加磷对提高地表N2 O的排放量有统计学意义(p<0.01);低氮及低氮加磷也提高了地表N2 O的排放量,但是不具有统计学意义.施肥对地表N2 O的排放量的影响主要表现在施肥初期,施肥后一周内,添加氮肥会导致N2 O的排放量出现一个明显的峰值.随着时间的推移,N2 O的排放量明显下降,直到与对照样地的差异不具有统计学意义.%Using the most common method for sampling and analyzing gas sample ,the static chamber‐gas chromatography method ,we studied the greenhouse gas fluxes of the fir forest soil ,exploring the response pattern of the major greenhouse gases of nitrogen and phosphorus addition and the mechanism of green‐house gas fluxes of fir forest soil at Shixi forest .T his experiment show s high nitrogen and high nitrogen and phosphorus significantly improved surface N2O emissions(p <0.01) .low nitrogen and low nitrogen plus phosphorus increased surface N2 O emissions ,but did not reach the level of significance .The effect of fertilization on the N2 O emissions was mainly observed in the early stages of fertilization ,within a week after fertilization ,nitrogen fertilization will lead to an obvious peak of N 2 O ,and as time goes on ,N2 O e‐missions decreased until there was no significant difference compared with the blank .

  1. Additivity dominance

    Directory of Open Access Journals (Sweden)

    Paul Rozin

    2009-10-01

    Full Text Available Judgments of naturalness of foods tend to be more influenced by the process history of a food, rather than its actual constituents. Two types of processing of a ``natural'' food are to add something or to remove something. We report in this study, based on a large random sample of individuals from six countries (France, Germany, Italy, Switzerland, UK and USA that additives are considered defining features of what makes a food not natural, whereas ``subtractives'' are almost never mentioned. In support of this, skim milk (with major subtraction of fat is rated as more natural than whole milk with a small amount of natural vitamin D added. It is also noted that ``additives'' is a common word, with a synonym reported by a native speaker in 17 of 18 languages, whereas ``subtractive'' is lexicalized in only 1 of the 18 languages. We consider reasons for additivity dominance, relating it to omission bias, feature positive bias, and notions of purity.

  2. Hyperspectral remote sensing of foliar nitrogen content

    OpenAIRE

    Knyazikhin, Yuri; Schull, Mitchell A.; Stenberg, Pauline; Mõttus, Matti; Rautiainen, Miina; Yan YANG; Marshak, Alexander; Latorre Carmona, Pedro; Kaufmann, Robert K.; Lewis, Philip; Disney, Mathias I.; Vanderbilt, Vern; Davis, Anthony B.; Baret, Frederic; Jacquemoud, Stephane

    2012-01-01

    A strong positive correlation between vegetation canopy bidirectional reflectance factor (BRF) in the near infrared (NIR) spectral region and foliar mass-based nitrogen concentration (%N) has been reported in some temperate and boreal forests. This relationship, if true, would indicate an additional role for nitrogen in the climate system via its influence on surface albedo and may offer a simple approach for monitoring foliar nitrogen using satellite data. We report, however, that the previo...

  3. Soil and fertilizer nitrogen

    International Nuclear Information System (INIS)

    As a result of the intensified practices and effectively diminishing land resources per capita, increasing weights of both native soil- and added fertilizer-nitrogen will be lost to agriculture and its products, and will find their way into the environment. Soil-nitrogen levels and contingent productivity can nevertheless be maintained in the face of these losses on the basis of improved soil-N management. In some local situations nitrate levels in water for drinking purposes are likely to continue rising. In some cases agriculture and clearance practices are only one of several sources. In others they are clearly mainly responsible. In developing countries these losses represent those of a relatively increasingly costly input. This is due to the fact that industrial fertilizer nitrogen production is a particularly high energy-consuming process. In the more advanced industrialized countries they represent an addition to the problems and costs of environmental quality and health protection. The programmes, information and data reviewed here suggest that these problems can be contained by improved and extended soil and water management in agriculture on the basis of existing technology. In particular there appears to be enormous scope for the better exploitation of existing legumes both as non-legume crop alternatives or as biofertilizers which also possess more desirable C:N ratios than chemical fertilizer

  4. Forest fuel reduces the nitrogen load

    International Nuclear Information System (INIS)

    A study of the literature was made on the basis of the following hypothesis: ''If nitrogen-rich felling residues are removed from the forest, the nitrogen load on the forest ecosystem is decreased and the risk of nitrogen saturation also decreases''. The study was designed to provide information on how the nitrogen situation is influenced if felling residues are removed from nitrogen-loaded forests and used as fuel. Felling residues release very little nitrogen during the first years after felling. They can immobilize nitrogen from the surroundings, make up a considerable addition to the nitrogen store in the soil, but also release nitrogen in later stages of degradation. The slash has an influence on the soil climate and thus on soil processes. Often there is an increase in the mineralization of litter and humus below the felling residues. At the same time, nitrification is favoured, particularly if the slash is left in heaps. Felling residues contain easily soluble nutrients that stimulate the metabolization of organic matter that otherwise is rather resistant to degradation. The slash also inhibits the clear-cut vegetation and its uptake of nitrogen. These effects result in increased leaching of nitrogen and minerals if the felling residues are left on the site. (99 refs.)

  5. Additivity dominance

    OpenAIRE

    Paul Rozin; Claude Fischler; Christy Shields-Argeles

    2009-01-01

    Judgments of naturalness of foods tend to be more influenced by the process history of a food, rather than its actual constituents. Two types of processing of a ``natural'' food are to add something or to remove something. We report in this study, based on a large random sample of individuals from six countries (France, Germany, Italy, Switzerland, UK and USA) that additives are considered defining features of what makes a food not natural, whereas ``subtractives'' are almost never mentioned....

  6. Coastal nitrogen plumes and their relationship with seagrass distribution

    Science.gov (United States)

    Fernandes, Milena B.; Benger, Simon; Stuart-Williams, Hilary; Gaylard, Sam; Bryars, Simon

    2015-12-01

    Urbanised coastlines are affected by cumulative impacts from a variety of anthropogenic stressors, but spatial information on the distribution of these stressors at the local scale is scarce, hindering the ability of managers to prioritise mitigation options. This work investigated the spatial footprint of land-based nitrogen discharges to a metropolitan coastline and assessed the potential role of this stressor alone on seagrass dynamics at the scale of the ecosystem. The macroalga Caulocystis cephalornithos was used as a time-integrative sampler of nitrogen in the water column over 202 sites monitored across an area of ˜800 km2. The stable isotopic signature of nitrogen in tissues (δ15N) was used to map plumes of anthropogenic origin. The surface area of these plumes was found to be proportional to nitrogen loads from land. The largest plume was associated with discharges from an industrialised estuary and a wastewater treatment plant, where a monthly nitrogen load in excess of 110 tonnes affected an area >80 km2. The location and size of the plumes changed with seasons as a result of wind forcing and rainfall/wastewater reuse. The location of the plumes was compared to published seagrass distribution obtained from video transects. Dense seagrass meadows only occurred in areas unimpacted by plumes throughout the year, mostly in shallow (<5 m) regions for Amphibolis antarctica, and deeper (5-10 m) for Posidonia sp., possibly as a result of this species higher tolerance of low light conditions. This higher tolerance might also explain why Posidonia sp. is observed to preferentially recolonise areas of previous loss in the region. While a decrease in the spatial footprint of nutrient plumes has created conditions for natural seagrass recolonisation in some areas, it did not halt seagrass loss in others, suggesting the influence of additional stressors such as wave dynamics and light attenuation due to turbid/coloured stormwater.

  7. Soil carbon storage and N{sub 2}O emissions from wheat agroecosystems as affected by free-air CO{sub 2} enrichment (FACE) and nitrogen treatments. Final Report - February 12, 1999

    Energy Technology Data Exchange (ETDEWEB)

    S. W. Leavitt; A. D. Matthias; T. L. Thompson; R. A. Rauschkolb

    1999-02-17

    Rising atmospheric CO{sub 2} concentrations have prompted concern about response of plants and crops to future elevated CO{sub 2} levels, and particularly the extent to which ecosystems will sequester carbon and thus impact the rate of rise of CO{sub 2} concentrations. Free-air CO{sub 2} enrichment (FACE) experimentation was used with wheat agroecosystems for two growing seasons to assess effects of CO{sub 2} and soil nitrogen. Over 20 researchers on this experiment variously examined plant production and grain yield, phenology, length of growing season, water-use efficiency ecosystem production, below ground processes (eg, root and microbial activity, carbon and nitrogen cycling), etc.

  8. Nitrous oxide and methane fluxes in south Brazilian gleysol as affected by nitrogen fertilizers Fluxos de óxido nitroso e de metano em gleissolo influenciados pela aplicação de fertilizantes nitrogenados no sul do Brasil

    OpenAIRE

    Josiléia Acordi Zanatta; Cimélio Bayer; Frederico C.B. Vieira; Juliana Gomes; Michely Tomazi

    2010-01-01

    Nitrogen fertilizers increase the nitrous oxide (N2O) emission and can reduce the methane (CH4) oxidation from agricultural soils. However, the magnitude of this effect is unknown in Southern Brazilian edaphoclimatic conditions, as well as the potential of different sources of mineral N fertilizers in such an effect. The aim of this study was to investigate the effects of different mineral N sources (urea, ammonium sulphate, calcium nitrate, ammonium nitrate, Uran, controlled- release N ferti...

  9. 土壤添加亚砷酸钠对大豆生长和植株氮、磷、钾含量的影响%Effects of arsenic addition in soil on soybean growth and the content of nitrogen,phosphorus and potassium in soybean plant

    Institute of Scientific and Technical Information of China (English)

    杨兰芳; 彭小兰; 裴艳艳; 陈瑞雪

    2011-01-01

    Arsenic(As) is toxic to plants and animals.A soil pot experiment with the arsenic addition levels of 0,5.0,10.0,30.0,50.0,100.0 mg · kg^-1 was conducted to investigate the effects of soil arsenic addition on soybean growth and the content of nitrogen,phosphorus and potassium.The results showed that when soil arsenic addition was at a level of 50 mg · kg^-1,soybean demonstrated a series of toxic symptoms with crimple and dark green leaves,withered leaf edge,dwarfing plant and delayed maturation.The plant heights of soybean decreased with increase of soil arsenic supplement and there was significant negative,exponential correlation between the soil arsenic additions and plant heights of soybean.Soil arsenic addition of 100 mg · kg^-1 caused 41.5% decrease in plant height,43.4% in total biomass and 56.1% in the yield of soybean grain.The ratio of root biomass to that of aerial parts and of biomass of leaf and stem to that of aerial parts increased,while the ratio of grain biomass to that of leaf and stem,aerial parts and total biomass was decreased.These results suggested that high soil arsenic addition suppressed the growth of aerial parts and grain.Soil arsenic pollution had significant effects on the content of nitrogen,phosphorus and potassium in soybean.When soil arsenic addition was 100 mg · kg^-1,compared to control(no arsenic addition),soybean nitrogen and phosphorus content in grains,roots and leaves and stems,potassium content in leaves and stems and in roots increased significantly,but the potassium content in grains decreased significantly,while the ratio of nitrogen,phosphorus and potassium content in soybean grains to that in leaves and stems and to that in roots decreased significantly.This implied that arsenic stress suppressed the translocation of the nitrogen,phosphorus and potassium in leaves and stems to grains.In summary,over 50.0 mg · kg^-1 soil arsenic addition could be toxic to soybean growth,but soybean could adapt to the arsenic

  10. [Distribution and bioavailability of nitrogen and phosphorus species in the urban dusts from Hefei City].

    Science.gov (United States)

    Li, Ru-Zhong; Zhou, Ai-Jia; Tong, Fang; Li, Feng; Qian, Jia-Zhong

    2012-04-01

    To find out the distribution and bioavailability of nitrogen (N) and phosphorus (P) species in the urban dusts of Hefei City, 52 samples were collected from impervious areas with six different urban land-use types. The contents of ammonia nitrogen (NH4(+) -N), nitrate nitrogen (NO3(-) -N), exchangeable P (Ex-P), Al-bound P (Al-P), Fe-bound P (Fe-P), occluded P (Oc-P), Ca-bound P (Ca-P), detrital apatite P (De-P), organic P (Or-P) as well as total nitrogen (TN) and total phosphorus (TP) were measured by sequential extraction methods. The studies on spatial distribution, correlation and bioavailability of nitrogen and phosphorus species were made according to the analyzed data. The results show that the TN is composed mainly of organic nitrogen (Or-N) while the TP consists chiefly of inorganic phosphorus (IP) in the urban dusts of Hefei City, and the spatial variability of nitrogen and phosphorus species contents are greatly affected by the mode of urban land-use type. In addition, there are significant correlations among partial nitrogen and phosphorus forms in dusts. Corresponding to different urban land-use types such as industrial area, commercial area, residential area, educational area, traffic area and public landscapes and city squares, the average ratios of bioavailable nitrogen content (the sum of NH4(+) -N and NO3(-) -N) to TN are 8.87%, 9.60%, 6.68%, 9.37%, 8.20% and 8.17%, respectively, while the mean ratios of bioavailable phosphorus content (the sum of Ex-P, Al-P and Fe-P) to TP, are equal to 6.70%, 18.19%, 10.10%, 9.69%, 10.64% and 14.03%, respectively. PMID:22720560

  11. Effect of ensiling time and exogenous protease addition to whole-plant corn silage of various hybrids, maturities, and chop lengths on nitrogen fractions and ruminal in vitro starch digestibility.

    Science.gov (United States)

    Ferraretto, L F; Crump, P M; Shaver, R D

    2015-12-01

    The objective of this study was to evaluate the effects of ensiling time and exogenous protease addition on soluble CP (% of CP), ammonia-N (% of N), and ruminal in vitro starch digestibility (ivSD) of whole-plant corn silage (WPCS) from 3 hybrids, 2 maturities, and 2 chop lengths. Samples from 3 nonisogenic hybrids [brown midrib containing the bm3 gene mutation (BM3), dual-purpose (DP), or floury-leafy (LFY)] at 2 harvest maturities [2/3 kernel milk line (early) or 7d later (late)] with 2 theoretical lengths of cut settings (0.64 or 1.95cm) on a forage harvester were collected at harvest, treated with or without exogenous protease, and ensiled in triplicate in vacuum heat-sealed plastic bags for 0, 30, 60, 120, and 240d. Thus, the experiment consisted of 120 treatments (3 hybrids × 2 maturities × 2 chop lengths × 2 protease treatments × 5 time points) and 360 mini-silos (3 replications per treatment). Vitreousness, measured by dissection on unfermented kernels on the day of harvest, averaged 66.8, 65.0, and 59.0% for BM3, DP, and LFY, respectively. A protease × maturity interaction was observed with protease increasing ivSD in late but not early maturity. Ensiling time × hybrid interactions were observed for ammonia-N and soluble CP concentrations with greater values for FLY than other hybrids only after 120d of ensiling. Ensiling time × hybrid or protease × hybrid interactions were not observed for ivSD. Measurements of ivSD were greatest for FLY and lowest for BM3. Length of the ensiling period did not attenuate negative effects of kernel vitreousness or maturity on ivSD in WPCS. Results suggest that the dosage of exogenous protease addition used in the present study may reduce but not overcome the negative effects of maturity on ivSD in WPCS. No interactions between chop length and ensiling time or exogenous protease addition were observed for ivSD. PMID:26433421

  12. 饲粮粗蛋白质水平对泌乳水牛产奶量及氮代谢的影响%Dietary Crude Protein Level Affects Milk Yield and Nitrogen Metabolism of Lactating Water Buffalo

    Institute of Scientific and Technical Information of China (English)

    邹彩霞; 韦升菊; 梁贤威; 覃广胜; 杨炳壮; 杨承剑

    2012-01-01

    This experiment was conducted to investigate the effects of dietary crude protein level on milk yield and nitrogen metabolism of lactating water buffalo. A 4 x 4 Latin square experiment design was used in the experiment. Sixteen healthy early lactation water buffalo with similar milk yield in the last lactation and 2 or 3 parities were divided into 4 groups to carry out animal experiment, and digestion and metabolism experiment. The animals were randomly divided into 4 groups and fed diets containing varying levels of crude protein (16. 0% , 15. 2% , 14. 4% and 13. 6% ). There were 4 feeding trial periods, each period included 21 d with 7 d adaptation period, and whole experiment lasted for 84 d. According to Latin square experiment design, each group in each period was fed different levels of dietary crude protein. Two nitrogen digestion and metabolism trials were conducted on the last 4 days of the second and the fourth feeding trial period. The results showed that there were significant differences in total nitrogen intake, digestible nitrogen, milk nitrogen/total nitrogen intake and apparent nitrogen digestibility among some groups (P 0. 05). There were no significant differences in milk yield, milk protein percentage, milk fat percentage, milk non-solid percentage whole milk solids content and lactose percentage among each group (P > 0. 05). There were no significant differences in the contents of serum total protein and urea nitrogen (P > 0. 05). The relationship between nitrogen intake (x, g/d) and fat corrected milk (y, kg/d) was showed as follows; y = ?0. 001 6x2 +0. 955 6x ?129. 91. In conclusion, dietary crude protein level has no significant effect on performance and blood biochemical indices of lactating water buffalo, according to the curvilinear relationship between nitrogen intake and fat corrected milk, when the nitrogen intake is 298. 625 g/d, the max standard milk yield of water buffalo is 12.773 kg/d.%本试验旨在研究饲粮粗蛋白质水

  13. Nitrogen deposition to lakes in national parks of the western Great Lakes region: Isotopic signatures, watershed retention, and algal shifts

    Science.gov (United States)

    Hobbs, William O.; Lafrancois, Brenda Moraska; Stottlemyer, Robert; Toczydlowski, David; Engstrom, Daniel R.; Edlund, Mark B.; Almendinger, James E.; Strock, Kristin E.; VanderMeulen, David; Elias, Joan E.; Saros, Jasmine E.

    2016-03-01

    Atmospheric deposition is a primary source of reactive nitrogen (Nr) to undisturbed watersheds of the Great Lakes region of the U.S., raising concerns over whether enhanced delivery over recent decades has affected lake ecosystems. The National Atmospheric Deposition Program (NADP) has been measuring Nr deposition in this region for over 35 years. Here we explore the relationships among NADP-measured Nr deposition, nitrogen stable isotopes (δ15N) in lake sediments, and the response of algal communities in 28 lakes situated in national parks of the western Great Lakes region of the U.S. We find that 36% of the lakes preserve a sediment δ15N record that is statistically correlated with some form of Nr deposition (total dissolved inorganic N, nitrate, or ammonium). Furthermore, measured long-term (since 1982) nitrogen biogeochemistry and inferred critical nitrogen loads suggest that watershed nitrogen retention and climate strongly affect whether sediment δ15N is related to Nr deposition in lake sediment records. Measurements of algal change over the last ~ 150 years suggest that Nr deposition, in-lake nutrient cycling, and watershed inputs are important factors affecting diatom community composition, in addition to direct climatic effects on lake physical limnology. The findings suggest that bulk sediment δ15N does reflect Nr deposition in some instances. In addition, this study highlights the interactive effects of Nr deposition and climate variability.

  14. A tradeoff frontier for global nitrogen use and cereal production

    International Nuclear Information System (INIS)

    Nitrogen fertilizer use across the world’s croplands enables high-yielding agricultural production, but does so at considerable environmental cost. Imbalances between nitrogen applied and nitrogen used by crops contributes to excess nitrogen in the environment, with negative consequences for water quality, air quality, and climate change. Here we utilize crop input-yield models to investigate how to minimize nitrogen application while achieving crop production targets. We construct a tradeoff frontier that estimates the minimum nitrogen fertilizer needed to produce a range of maize, wheat, and rice production levels. Additionally, we explore potential environmental consequences by calculating excess nitrogen along the frontier using a soil surface nitrogen balance model. We find considerable opportunity to achieve greater production and decrease both nitrogen application and post-harvest excess nitrogen. Our results suggest that current (circa 2000) levels of cereal production could be achieved with ∼50% less nitrogen application and ∼60% less excess nitrogen. If current global nitrogen application were held constant but spatially redistributed, production could increase ∼30%. If current excess nitrogen were held constant, production could increase ∼40%. Efficient spatial patterns of nitrogen use on the frontier involve substantial reductions in many high-use areas and moderate increases in many low-use areas. Such changes may be difficult to achieve in practice due to infrastructure, economic, or political constraints. Increases in agronomic efficiency would expand the frontier to allow greater production and environmental gains

  15. A tradeoff frontier for global nitrogen use and cereal production

    Science.gov (United States)

    Mueller, Nathaniel D.; West, Paul C.; Gerber, James S.; MacDonald, Graham K.; Polasky, Stephen; Foley, Jonathan A.

    2014-05-01

    Nitrogen fertilizer use across the world’s croplands enables high-yielding agricultural production, but does so at considerable environmental cost. Imbalances between nitrogen applied and nitrogen used by crops contributes to excess nitrogen in the environment, with negative consequences for water quality, air quality, and climate change. Here we utilize crop input-yield models to investigate how to minimize nitrogen application while achieving crop production targets. We construct a tradeoff frontier that estimates the minimum nitrogen fertilizer needed to produce a range of maize, wheat, and rice production levels. Additionally, we explore potential environmental consequences by calculating excess nitrogen along the frontier using a soil surface nitrogen balance model. We find considerable opportunity to achieve greater production and decrease both nitrogen application and post-harvest excess nitrogen. Our results suggest that current (circa 2000) levels of cereal production could be achieved with ˜50% less nitrogen application and ˜60% less excess nitrogen. If current global nitrogen application were held constant but spatially redistributed, production could increase ˜30%. If current excess nitrogen were held constant, production could increase ˜40%. Efficient spatial patterns of nitrogen use on the frontier involve substantial reductions in many high-use areas and moderate increases in many low-use areas. Such changes may be difficult to achieve in practice due to infrastructure, economic, or political constraints. Increases in agronomic efficiency would expand the frontier to allow greater production and environmental gains.

  16. Soil warming, carbon–nitrogen interactions, and forest carbon budgets

    OpenAIRE

    Melillo, Jerry M.; Butler, Sarah; Johnson, Jennifer,; Mohan, Jacqueline; Steudler, Paul; Lux, Heidi; Burrows, Elizabeth; Bowles, Francis; Smith, Rose; Scott, Lindsay; Vario, Chelsea; Hill, Troy; Burton, Andrew; Zhou, Yu-mei; Tang, Jim

    2011-01-01

    Soil warming has the potential to alter both soil and plant processes that affect carbon storage in forest ecosystems. We have quantified these effects in a large, long-term (7-y) soil-warming study in a deciduous forest in New England. Soil warming has resulted in carbon losses from the soil and stimulated carbon gains in the woody tissue of trees. The warming-enhanced decay of soil organic matter also released enough additional inorganic nitrogen into the soil solution to support the observ...

  17. Variation in foliar nitrogen and albedo in response to nitrogen fertilization and elevated CO2.

    Science.gov (United States)

    Wicklein, Haley F; Ollinger, Scott V; Martin, Mary E; Hollinger, David Y; Lepine, Lucie C; Day, Michelle C; Bartlett, Megan K; Richardson, Andrew D; Norby, Richard J

    2012-08-01

    Foliar nitrogen has been shown to be positively correlated with midsummer canopy albedo and canopy near infrared (NIR) reflectance over a broad range of plant functional types (e.g., forests, grasslands, and agricultural lands). To date, the mechanism(s) driving the nitrogen–albedo relationship have not been established, and it is unknown whether factors affecting nitrogen availability will also influence albedo. To address these questions, we examined variation in foliar nitrogen in relation to leaf spectral properties, leaf mass per unit area, and leaf water content for three deciduous species subjected to either nitrogen (Harvard Forest, MA, and Oak Ridge, TN) or CO(2) fertilization (Oak Ridge, TN). At Oak Ridge, we also obtained canopy reflectance data from the airborne visible/infrared imaging spectrometer (AVIRIS) to examine whether canopy-level spectral responses were consistent with leaf-level results. At the leaf level, results showed no differences in reflectance or transmittance between CO(2) or nitrogen treatments, despite significant changes in foliar nitrogen. Contrary to our expectations, there was a significant, but negative, relationship between foliar nitrogen and leaf albedo, a relationship that held for both full spectrum leaf albedo as well as leaf albedo in the NIR region alone. In contrast, remote sensing data indicated an increase in canopy NIR reflectance with nitrogen fertilization. Collectively, these results suggest that altered nitrogen availability can affect canopy albedo, albeit by mechanisms that involve canopy-level processes rather than changes in leaf-level reflectance. PMID:22294028

  18. Enhanced cytocompatibility of silver-containing biointerface by constructing nitrogen functionalities

    International Nuclear Information System (INIS)

    Graphical abstract: Constructing nitrogen functionalities is promising method to enhance cytocompatibility of the biointerface by simultaneous Ag and N2 plasma modification. - Highlights: • N2 plasma immersion ion implantation (PIII) treatment generates plenty of nitrogen functionalities on polymer substrate. • N2 PIII treatment increases surface roughness and hydrophilicity and improves its capability to adsorb protein. • Simultaneous Ag and N2 plasma modification constructs nitrogen functionalities to enhance cytocompatibility of the biointerface. - Abstract: Silver (Ag) has recently been introduced into polymeric biomedical implants by plasma immersion ion implantation (PIII) to enhance the antibacterial capability. However, Ag ions and nanoparticles can increase the cytotoxicity and inhibit cellular proliferation and the relationship is time- and dose-dependent. In this study, Ag and N2 PIII is conducted in concert to produce nitrogen functional groups as well as Ag-containing biointerface. In addition to the creation of nitrogen functionalities, the surface roughness and hydrophilicity are improved in favor of protein adsorption. Compared to the biointerface created by Ag PIII only, the nitrogen functionalities generated by N2 co-PIII do not affect DNA synthesis and the total protein level but evidently enhance cellular adhesion, viability, and proliferation at the biointerface. The modified surface is observed to upregulate the osteogenesis-related marker expression of bone cells in contact. Our findings suggest that dual Ag and N2 PIII is a desirable technique to enhance both the cytocompatibility and antibacterial capability of medical polymers

  19. 造纸白泥和粉煤灰的添加对污泥消化液中氮磷回收的影响%Recovery of nitrogen and phosphorus from digested effluent of sludge by paper mill lime mud and fly ash addition

    Institute of Scientific and Technical Information of China (English)

    李小建; 冯文谦; 王德汉; 邓加曦; 周振鹏

    2012-01-01

    FA addition, when the aeration time was 12 h, the recovery rates of pO34- -P and NHa-N were only 20% and 19% , respectively. Therefore, it was important to recover the nitrogen and phosphorus from anaerobically digested ef- fluent of sludge with PMLM and FA addition. The results also showed that the lifting speed of pH accelerated when HRT increased, and the bigger the HRT was, the larger the lifting range was.

  20. Nitrogen vacancy complexes in nitrogen irradiated metals

    International Nuclear Information System (INIS)

    Gas desorption and positron annihilation techniques have been employed to study the evolution of nitrogen associated defects in nitrogen irradiated metals: Fe, Ni, Mo and W. Nitrogen in these metals has a rather high affinity to vacancy type defects. The results obtained for low irradiation dose show that substitutional nitrogen (NV; with V = vacancy) is formed. The nitrogen vacancy complex dissociates at temperatures ranging from 350 K for Ni to 900 K for Mo and 1,100 K for W. At high doses defects are formed which can be characterized as nitrogen saturated vacancy clusters. These defect, as observed by helium probing, disappear during annealing for nickel at 800 K, and for Mo at 1,100 K. The direct observation of the desorbing nitrogen for nickel and molybdenum reveals a very fast desorption transient at the dissociation temperature of the clusters. This is the characteristic desorption transient of a small nitride cluster, e.g., by shrinkage with constant rate. For iron the nitrogen desorption is more complicated because of a general background that continuously rises with temperature. With the positron beam technique depth information was obtained for defects in iron and the defect character could be established with the help of the information provided on annihilation with conduction and core electrons of the defect trapped positrons

  1. Understanding Nitrogen Fixation

    Energy Technology Data Exchange (ETDEWEB)

    Paul J. Chirik

    2012-05-25

    The purpose of our program is to explore fundamental chemistry relevant to the discovery of energy efficient methods for the conversion of atmospheric nitrogen (N{sub 2}) into more value-added nitrogen-containing organic molecules. Such transformations are key for domestic energy security and the reduction of fossil fuel dependencies. With DOE support, we have synthesized families of zirconium and hafnium dinitrogen complexes with elongated and activated N-N bonds that exhibit rich N{sub 2} functionalization chemistry. Having elucidated new methods for N-H bond formation from dihydrogen, C-H bonds and Broensted acids, we have since turned our attention to N-C bond construction. These reactions are particularly important for the synthesis of amines, heterocycles and hydrazines with a range of applications in the fine and commodity chemicals industries and as fuels. One recent highlight was the discovery of a new N{sub 2} cleavage reaction upon addition of carbon monoxide which resulted in the synthesis of an important fertilizer, oxamide, from the diatomics with the two strongest bonds in chemistry. Nitrogen-carbon bonds form the backbone of many important organic molecules, especially those used in the fertilizer and pharamaceutical industries. During the past year, we have continued our work in the synthesis of hydrazines of various substitution patterns, many of which are important precursors for heterocycles. In most instances, the direct functionalization of N{sub 2} offers a more efficient synthetic route than traditional organic methods. In addition, we have also discovered a unique CO-induced N{sub 2} bond cleavage reaction that simultaneously cleaves the N-N bond of the metal dinitrogen compound and assembles new C-C bond and two new N-C bonds. Treatment of the CO-functionalized core with weak Broensted acids liberated oxamide, H{sub 2}NC(O)C(O)NH{sub 2}, an important slow release fertilizer that is of interest to replace urea in many applications. The

  2. Woody encroachment by nitrogen-fixing species: impacts on nitrogen biogeochemistry expressed through nitrogen trace gases

    Science.gov (United States)

    Sparks, J. P.; West, J. B.; Boutton, T. W.

    2011-12-01

    Woody plant encroachment is a globally important vegetation change that continues to transform former grasslands or savannas into woodlands. This dramatic and geographically widespread phenomenon appears to be driven primarily by human land use changes, including reduced fire frequency and heavy livestock grazing. Observed effects of increased woody plant abundance in grasslands generally include alterations of above- and belowground productivity, changes in the chemistry of litter inputs, modifications to rooting depths and distributions, altered biogeochemical and hydrologic processes, and changes in microclimate and energy balance. These changes to fundamental ecosystem characteristics have strong, but relatively poorly understood, potential to modify biogeochemical processes that can themselves influence regional and global climate through biogeochemistry-climate feedbacks. In addition, in South Texas woody encroachment has occurred across a complex landscape differing in soil type and water retention. This work tests the hypothesis that woody encroachment, in addition to increasing total nitrogen stocks in the system, has increased nitrogen losses due to increased rates of nitrogen soil gas efflux. Under dry soil conditions and in contrast to this hypothesis, reactive nitrogen soil efflux (NO + NOy + NH3) was 21.53 ± 3.4 ng N m-2 s-1 in intact grasslands compared to 6.23 ± 1.6 ng N m-2 s-1 in woodlands on the same soil type. The non-reactive nitrogen gas, nitrous oxide, was similar in magnitude between the grassland and encroached sites (~ 7 ng N m-2 s-1). Under moist soil conditions, the magnitude of flux increased and order of magnitude, but did not change the relative ranking. Measurements of soil respiration rate and microbial biomass suggest higher microbial activity in the encroached environment and potentially higher rates of immobilization by plants and microbes. Landscape position had a large overall effect on soil nitrogen trace gas efflux with

  3. Effect of Nitrogen Implantation on Metal Transfer during Sliding Wear under Ambient Conditions

    Directory of Open Access Journals (Sweden)

    Luke Autry

    2013-01-01

    Full Text Available Nitrogen implantation in Interstitial-Free steel was evaluated for its impact on metal transfer and 1100 Al rider wear. It was determined that nitrogen implantation reduced metal transfer in a trend that increased with dose; the Archard wear coefficient reductions of two orders of magnitude were achieved using a dose of 2e17 ions/cm2, 100 kV. Cold-rolling the steel and making volumetric wear measurements of the Al-rider determined that the hardness of the harder material had little impact on volumetric wear or friction. Nitrogen implantation had chemically affected the tribological process studied in two ways: directly reducing the rider wear and reducing the fraction of rider wear that ended up sticking to the ISF steel surface. The structure of the nitrogen in the ISF steel did not affect the tribological behavior because no differences in friction/wear measurements were detected after postimplantation heat treating to decompose the as-implanted ε-Fe3N to γ-Fe4N. The fraction of rider-wear sticking to the steel depended primarily on the near-surface nitrogen content. Covariance analysis of the debris oxygen and nitrogen contents indicated that nitrogen implantation enhanced the tribo-oxidation process with reference to the unimplanted material. As a result, the reduction in metal transfer was likely related to the observed tribo-oxidation in addition to the introduction of nitride wear elements into the debris. The primary Al rider wear mechanism was stick-slip, and implantation reduced the friction and friction noise associated with that wear mechanism. Calculations based on the Tabor junction growth formula indicate that the mitigation of the stick-slip mechanism resulted from a reduced adhesive strength at the interface during the sticking phase.

  4. Nitrogen vertical distribution by canopy reflectance spectrum in winter wheat

    International Nuclear Information System (INIS)

    Nitrogen is a key factor for plant photosynthesis, ecosystem productivity and leaf respiration. Under the condition of nitrogen deficiency, the crop shows the nitrogen deficiency symptoms in the bottom leaves, while excessive nitrogen will affect the upper layer leaves first. Thus, timely measurement of vertical distribution of foliage nitrogen content is critical for growth diagnosis, crop management and reducing environmental impact. This study presents a method using bi-directional reflectance difference function (BRDF) data to invert foliage nitrogen vertical distribution. We developed upper-layer nitrogen inversion index (ULNI), middle-layer nitrogen inversion index (MLNI) and bottom-layer nitrogen inversion index (BLNI) to reflect foliage nitrogen inversion at upper layer, middle layer and bottom layer, respectively. Both ULNI and MLNI were made by the value of the ratio of Modified Chlorophyll Absorption Ration Index to the second Modified Triangular Vegetation Index (MCARI/MTVI2) referred to as canopy nitrogen inversion index (CNII) in this study at ±40° and ±50°, and at ±30° and ±40° view angles, respectively. The BLNI was composed by the value of nitrogen reflectance index (NRI) at ±20° and ±30° view angles. These results suggest that it is feasible to measure foliage nitrogen vertical-layer distribution in a large scale by remote sensing

  5. Nitrogen availability and defense of tomato against two-spotted spider mite

    NARCIS (Netherlands)

    Hoffland, E.; Dicke, M.; Tintelen, van W.; Dijkman, H.; Beusichem, van M.L.

    2000-01-01

    The aim of this work was to study how nitrogen availability affects within-plant allocation to growth and secondary metabolites and how this allocation affects host selection by herbivores. Tomato plants (Lycopersicon esculentum) were grown at six levels of nitrogen availability. When nitrogen avail

  6. 40 CFR 77.6 - Penalties for excess emissions of sulfur dioxide and nitrogen oxides.

    Science.gov (United States)

    2010-07-01

    ... sulfur dioxide and nitrogen oxides. (a)(1) If excess emissions of sulfur dioxide occur at the affected source or nitrogen oxide occur at an affected unit during any year, the owners and operators respectively... sulfur dioxide and nitrogen oxides. 77.6 Section 77.6 Protection of Environment ENVIRONMENTAL...

  7. 氮素和水分添加对贝加尔针茅草原土壤氨氧化微生物群落结构的影响%Differential Responses of Ammonia-oxidizers Communities to Nitrogen and Water Addition inStipa baicalensis Steppe, Inner Mongolia, Northern China

    Institute of Scientific and Technical Information of China (English)

    王杰; 李刚; 赖欣; 宋晓龙; 赵建宁; 杨殿林

    2015-01-01

    Atmospheric nitrogen deposition and precipitation as an important phenomenon of global climate change have a great impact on grassland ecosystems. However, little is known about how the soil ammonia-oxidizing microorganisms respond to the both changes. Ammonia oxidization is a crucial step in the soil nitrification and greatly inlfuenced by soil nitrogen availability. We used PCR and DGGE (denaturing gradient gel electrophoresis) approaches to investigate the responses of AOB (ammonia-oxidizing bacteria) 16S rRNA and AOA (ammonia-oxidizing archaea)amoA genes to nitrogen and water input inStipa baicalensis steppe, Inner Mongolia, northern China. After two years of nitrogen and water addition treatment, it was found that PNA (potential nitriifcation activity) was greatly enhanced by lower N fertilization treatment under water addition and higher N fertilization under no-water addition, while it decreased markedly in higher N fertilization under water addition. The community structure of AOB responded more sensitively to N fertilization and water input than AOA, resulting in the significantly decreased diversity in the AOB community along with a higher N fertilizer rate, but an obvious increase in the AOA community, demonstrating the active growth of AOA in higher N fertilization soils. Phylogenetic analysis showed that AOB communities were dominated byNitrosospira clusters3, 4 andNitrososmonas clusters 6 under water addition andNitrosospira culsters 1, 3 and 4 and under no-water addition, while AOA communities were grouped intoCrenarchaeote clusters 1, 2 and 5 under no-water addition and Crenarchaeote clusters 1, 2 and water lineage under water addition. The differences between the two water addition regimes strongly suggest that water input acts as an important role in shifting AOA and AOB communities. Moreover, in contrast to the AOA, the diversity of AOB was negatively correlated with total N, NH4+, NO3-andpH under water addition, implying a signiifcant N

  8. DOSES DE NITROGÊNIO E DENSIDADES DE PLANTAS COM E SEM UM REGULADOR DE CRESCIMENTO AFETANDO O TRIGO, CULTIVAR OR-1 NITROGEN DOSES AND PLANT DENSITIES WITH AND WITHOUT A GROWTH REGULATOR AFFECTING WHEAT, CULTIVAR OR-1

    Directory of Open Access Journals (Sweden)

    Jeferson Zagonel

    2002-02-01

    Full Text Available Doses de nitrogênio e elevadas populações de plantas são utilizadas visando a obtenção de altas produtividades em trigo. Porém, estes fatores podem promover o acamamento das plantas, especialmente para as cultivares de porte médio ou alto. O uso de produtos que reduzem a estatura das plantas pode minimizar este problema. Visando avaliar o efeito do regulador de crescimento trinexapc-ethyl em diferentes populações de plantas e doses de nitrogênio, na cultivar de trigo OR-1, instalou-se um experimento na Fazenda Escola "Capão da Onça", da Universidade Estadual de Ponta Grossa, em Ponta Grossa, PR, no ano de 1999. O delineamento experimental foi blocos ao acaso em esquema fatorial 2 x 3 x 4, em quatro repetições. Os vinte e quatro tratamentos constaram da aplicação de 125 g i.a./ha de trinexapac-ethyl e testemunha; densidades de 55, 75 e 112 plantas/m no espaçamento de 0,17m entre fileiras e doses de 0, 45, 90 e 135kg/ha de nitrogênio em cobertura. A aplicação do trinexapac-ethyl resultou em plantas com entre-nós mais curtos; em aumento do número de espigas/m e da produtividade. Com o aumento da dose de nitrogênio, ocorreu aumento da estatura das plantas, do número de espigas/m e da produtividade. Com o aumento da densidade de plantas, o diâmetro do caule, a massa seca das plantas e o número de grãos por espiga diminuíram mas o número de espigas/m e o peso de mil grãos aumentaram, sem afetarem a produtividade. Não ocorreu acamamento em nenhum dos tratamentos.Elevated nitrogen rates and high plant populations are adopted with the purpose of achieving high wheat yields. However, these factors may promote the lodging of the plants, especially for the medium and tall height cultivars. The utilization of products which reduce plant height could minimize this problem. With the aim of evaluating the effects of a growth regulator on different plant populations and nitrogen rates for the wheat cultivar OR-1, an experiment was

  9. Influence of nitrogen on the stress corrosion cracking resistance of austenitic stainless steels in chloride environment; Influence de l'azote sur la resistance a la corrosion sous contrainte d'aciers inoxydables austenitiques en milieu chlorure

    Energy Technology Data Exchange (ETDEWEB)

    Teysseyre, S

    2001-11-01

    The aim of this study is to investigate the influence of nitrogen additions on the Stress Corrosion Cracking (SSC) resistance of austenitic stainless steel in chloride environment. The investigation was carried out in two part: first, an experimental investigation with model industrial steels was carried out and secondly, numerical simulations based on the Corrosion Enhanced Plasticity Model were developed. Both slow strain rate tensile tests and constant load test of the different steels in boiling MgCl{sub 2} (153 deg C) at free potential show that, for a given plastic strain rate, nitrogen addition increases the critical stress for crack initiation without influencing the crack propagation rate. We observed that the creep rate under constant load was affected by the nitrogen content. As a consequence, the SCC behaviour (cracks density and propagation rate) depends on the nitrogen content. We thus confirm that the nitrogen content influences the corrosion - deformation interaction mechanisms via its positive contribution to the flow stress. These experimental results are reproduced semi-quantitatively by means of numerical simulations at the scale of crack. - dislocation interactions. The presence of nitrogen is modelled by an increased lattice friction stress, which in turn affects the dynamics of crack tip shielding by dislocation pile-ups. We conclude that nitrogen addition in austenitic stainless steels increases the SC crack initiation stress in proportion of the increased flow stress, without penalty in terms of SC crack propagation rate. (author)

  10. NOx abatement through urea additives

    International Nuclear Information System (INIS)

    Compared with catalytic denitrification, the use of urea in thermic processes of selective, non-catalytic reduction (SNCR), when combined with primary measures, constitutes an inexpensive alternative way of abating NOx emissions by means of combustion processes and waste incineration plants. A natural-gas fired and also electrically heated flow reactor was used in a number of fast series to systematically determine the influences of retention time, reaction temperature, reductant (ammonia or urea), molar ratio, and additives (ethanol) on the process. Balancing the input and output nitrogenous substances served to describe the partial shift through addition of ethanol of the reaction towards incomplete reduction and greater N2O emission. (orig.)

  11. Development of commercial nitrogen-rich stainless steels

    International Nuclear Information System (INIS)

    This paper reviews the development of nitrogen alloyed stainless steels. Nitrogen alloying of austenitic stainless steels started at an early stage and was to a large extent caused by nickel shortage. However, direct technical advantages such as increased strength of the nitrogen alloyed steels made them attractive alternatives to the current steels. It was not until the advent of the AOD (argon oxygen decarburisation) process in the late 1960s that nitrogen alloying could be controlled to such accuracy that it became successful commercially on a broader scale. The paper describes production aspects and how nitrogen addition influences microstructure and the resulting properties of austenitic and duplex stainless steels. For austenitic steels there are several reasons for nitrogen alloying. Apart from increasing strength nitrogen also improves structural stability, work hardening and corrosion resistance. For duplex steels nitrogen also has a decisive effect in controlling the microstructure during thermal cycles such as welding. (orig.)

  12. Reductions of Agricultural Nitrogen Use Under Consideration of Production and Price Risks

    OpenAIRE

    Finger, Robert

    2011-01-01

    Production and price risks affect optimal nitrogen use as well as the effects of nitrogen taxation if farmers’ risk aversion is taken into account. Our empirical analysis for Swiss maize production shows that risk-aversion leads to lower levels of nitrogen application, and nitrogen taxes lead to higher reductions of nitrogen use for risk-averse than for risk-neutral farmers. Moreover, risk-averse farmers face lower abatement costs. Sensitivity analyses, that consider expected shocks in price ...

  13. Nitrogen control of chloroplast differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, G.W.

    1992-07-01

    This project is directed toward understanding how the availability of nitrogen affects the accumulation of chloroplast pigments and proteins functioning in energy transduction and carbon metabolism. Molecular analyses performed with Chlamydomonas reinhardtii grown in a continuous culture system such that ammonium concentration is maintained at a low steady-state concentration so as to limit cell division. As compared to chloroplasts from cells of non-limiting nitrogen provisions, chloroplasts of N-limited cells are profoundly chlorophyll-deficient but still assimilate carbon for deposition of as starch and as storage lipids. Chlorophyll deficiency arises by limiting accumulation of appropriate nuclear-encoded mRNAs of and by depressed rates of translation of chloroplast mRNAs for apoproteins of reaction centers. Chloroplast translational effects can be partially ascribed to diminished rates of chlorophyll biosynthesis in N-limited cells, but pigment levels are not determinants for expression of the nuclear light-harvesting protein genes. Consequently, other signals that are responsive to nitrogen availability mediate transcriptional or post-transcriptional processes for accumulation of the mRNAs for LHC apoproteins and other mRNAs whose abundance is dependent upon high nitrogen levels. Conversely, limited nitrogen availability promotes accumulation of other proteins involved in carbon metabolism and oxidative electron transport in chloroplasts. Hence, thylakoids of N-limited cells exhibit enhanced chlororespiratory activities wherein oxygen serves as the electron acceptor in a pathway that involves plastoquinone and other electron carrier proteins that remain to be thoroughly characterized. Ongoing and future studies are also outlined.

  14. Dosis óptima económica de nitrógeno en maíz según potencial de producción y disponibilidad de nitrógeno en la región pampeana norte Economic optimal nitrogen rate as affected by yield potential and nitrogen supply in the northern pampas

    Directory of Open Access Journals (Sweden)

    Fernando Salvagiotti

    2011-12-01

    Full Text Available El maíz es el principal cereal de verano en la Región Pampeana norte de la Argentina donde los suelos presentan una deficiencia crónica de nitrógeno (N. La fertilización nitrogenada en maíz debe optimizar los niveles de N disponible a la siembra (Nds=Nds inic + N fertilizante para asegurar la máxima rentabilidad y evitar altas dosis que perjudiquen el ambiente. Los objetivos de este trabajo fueron: i comparar la capacidad de los modelos cuadrático-plateau (CP y esférico (Esf para estimar la respuesta a la fertilización con N; ii determinar umbrales críticos de Nds (UCNds en cultivos de alto (AR y bajo (BR rendimiento, y iii calcular en estas situaciones la dosis óptima económica de N (DOE y la eficiencia en el uso del N en la DOE (EA DOE con distinto Nds. Se analizaron 39 experimentos de fertilización nitrogenada (sitio-año-SA, los modelos CP y Esf ajustaron con precisión la relación entre rendimiento y Nds en toda la red, pero el modelo CP presentó dificultades para representar la forma asintótica de la curva de respuesta en algunos SA en particular. Los UCNds fueron de 137 y 161 kg N ha-1 en BR y AR. Utilizando una relación de precios maíz: N de 10:1, la DOE fue de 99 y 78 kg N ha-1 y la EA DOE de 28 y 17 kg grano kg N-1 para AR cuando Nds inic fue 40 y 80 kg N ha-1. En cambio para BR, para las mismas Ndsinic, la DOE fue de 71 y 49 kg N ha-1 con una EADOE de 15 y 8 kg grano kg N-1. Al cambiar la relación de precios a situaciones más desfavorables, la DOE y la EA DOE disminuyeron, pero con mayor magnitud en BR. Los resultados de este trabajo remarcan que, para un correcto diagnóstico de la fertilización nitrogenada en maíz, es importante definir el potencial de rendimiento del cultivo que permitirá alcanzar mayor rentabilidad haciendo un uso eficiente del fertilizante.Maize is the most important summer cereal in the Northern Pampas of Argentina where soils present severe nitrogen (N deficiency. N fertilization in

  15. Response of the abundance of key soil microbial nitrogen-cycling genes to multi-factorial global changes.

    Directory of Open Access Journals (Sweden)

    Ximei Zhang

    Full Text Available Multiple co-occurring environmental changes are affecting soil nitrogen cycling processes, which are mainly mediated by microbes. While it is likely that various nitrogen-cycling functional groups will respond differently to such environmental changes, very little is known about their relative responsiveness. Here we conducted four long-term experiments in a steppe ecosystem by removing plant functional groups, mowing, adding nitrogen, adding phosphorus, watering, warming, and manipulating some of their combinations. We quantified the abundance of seven nitrogen-cycling genes, including those for fixation (nifH, mineralization (chiA, nitrification (amoA of ammonia-oxidizing bacteria (AOB or archaea (AOA, and denitrification (nirS, nirK and nosZ. First, for each gene, we compared its sensitivities to different environmental changes and found that the abundances of various genes were sensitive to distinct and different factors. Overall, the abundances of nearly all genes were sensitive to nitrogen enrichment. In addition, the abundances of the chiA and nosZ genes were sensitive to plant functional group removal, the AOB-amoA gene abundance to phosphorus enrichment when nitrogen was added simultaneously, and the nirS and nirK gene abundances responded to watering. Second, for each single- or multi-factorial environmental change, we compared the sensitivities of the abundances of different genes and found that different environmental changes primarily affected different gene abundances. Overall, AOB-amoA gene abundance was most responsive, followed by the two denitrifying genes nosZ and nirS, while the other genes were less sensitive. These results provide, for the first time, systematic insights into how the abundance of each type of nitrogen-cycling gene and the equilibrium state of all these nitrogen-cycling gene abundances would shift under each single- or multi-factorial global change.

  16. Plasma polymerization of an ethylene-nitrogen gas mixture

    Science.gov (United States)

    Hudis, M.; Wydeven, T.

    1975-01-01

    A procedure has been developed whereby nitrogen can be incorporated into an organic film from an ethylene-nitrogen gas mixture using an internal electrode capacitively coupled radio frequency reactor. The presence of nitrogen has been shown directly by infrared transmittance spectra and electron spectroscopic chemical analysis data, and further indirect evidence was provided by dielectric measurements and by the reverse osmosis properties of the film. Preparation of a nitrogen containing film did not require vapor from an organic nitrogen containing liquid monomer. Some control over the bonding and stoichiometry of the polymer film was provided by the added degree of freedom of the nitrogen partial pressure in the gas mixture. This new parameter strongly affected the dielectric properties of the plasma polymerized film and could affect the reverse osmosis behavior.

  17. Episodic inputs of atmospheric nitrogen to the Sargasso Sea: Contributions to new production and phytoplankton blooms

    Science.gov (United States)

    Michaels, Anthony F.; Siegel, David A.; Johnson, Rodney J.; Knap, Anthony H.; Galloway, James N.

    1993-06-01

    Atmospheric wet deposition rates of nitrate and ammonia on Bermuda collected in the Atmosphere Ocean Chemistry Experiment (AEROCE) are compared with the synoptic measurements of carbon and nitrogen cycling from the U.S. Joint Global Ocean Flux Study (JGOFS) Bermuda Atlantic Time Series Study (BATS) station, 75 km southeast of Bermuda. Measurable deposition events were found on 23.8% of the days between October 1, 1988 and June 30, 1991. However, only a few of these events significantly contributed to the standing stocks of nitrogen and phytoplankton or rates of primary production. For 1.7% of the days each year, the atmospheric nitrogen deposition would have equaled the sinking particulate nitrogen flux as estimated by sediment traps. For only 0.2% of the time, would adequate nitrogen be deposited to a 20 m mixed layer to change the surface concentrations of particulate organic nitrogen by 10%. The results are dramatically different if all of the deposition remains confined to the upper l m of the water column enabling intense, surface phytoplankton blooms to occur. The occurrence of these near-surface blooms may be an important signal in the interpretation of satellite ocean color imagery, particularly when the satellite data are used to infer whole water-column phytoplankton stocks or productivity. Numerical simulations of the evolution of the near-surface mixed layer after a rainfall event indicate that low salinity surface waters would be mixed to the upper 10 m or so within 2-4 hours, except for wind speeds less than approximately 5m s-1. Thus, wet deposition induced surface algae blooms should only be observed under relatively calm meteorological conditions. In summary, wet deposition of nitrogen is a relatively unimportant process in affecting upper ocean nitrogen cycling for the Sargasso Sea off Bermuda, although in oceans with lower productivity and areas where deposition may increase with future industrial development, episodic deposition events may

  18. Soil warming, carbon-nitrogen interactions, and forest carbon budgets.

    Science.gov (United States)

    Melillo, Jerry M; Butler, Sarah; Johnson, Jennifer; Mohan, Jacqueline; Steudler, Paul; Lux, Heidi; Burrows, Elizabeth; Bowles, Francis; Smith, Rose; Scott, Lindsay; Vario, Chelsea; Hill, Troy; Burton, Andrew; Zhou, Yu-Mei; Tang, Jim

    2011-06-01

    Soil warming has the potential to alter both soil and plant processes that affect carbon storage in forest ecosystems. We have quantified these effects in a large, long-term (7-y) soil-warming study in a deciduous forest in New England. Soil warming has resulted in carbon losses from the soil and stimulated carbon gains in the woody tissue of trees. The warming-enhanced decay of soil organic matter also released enough additional inorganic nitrogen into the soil solution to support the observed increases in plant carbon storage. Although soil warming has resulted in a cumulative net loss of carbon from a New England forest relative to a control area over the 7-y study, the annual net losses generally decreased over time as plant carbon storage increased. In the seventh year, warming-induced soil carbon losses were almost totally compensated for by plant carbon gains in response to warming. We attribute the plant gains primarily to warming-induced increases in nitrogen availability. This study underscores the importance of incorporating carbon-nitrogen interactions in atmosphere-ocean-land earth system models to accurately simulate land feedbacks to the climate system. PMID:21606374

  19. [Effects of short-term continuous lighting with LED lamps and nitrogen nutrition conditions on quality of hydroponically grown purple lettuce].

    Science.gov (United States)

    Yu, Yi; Yang, Qi-chang; Liu, Wen-ke

    2015-11-01

    content and increased the ascorbic acid, soluble sugar and soluble protein contents greatly. In addition, nitrogen nutrition conditions affected the effectiveness of short-term continuous lighting on quality improvement rate of hydroponic lettuce remarkably. PMID:26915191

  20. Effect of nitrogen limitation on the ergosterol production by fed-batch culture of Saccharomyces cerevisiae.

    Science.gov (United States)

    Shang, Fei; Wen, Shaohong; Wang, Xi; Tan, Tianwei

    2006-04-10

    The diversity and content of available nitrogen sources in the growth medium both are very important in the accumulation of ergosterol in the yeast cell membrane. Growth on the good nitrogen sources such as ammonia can harvest more yeast cells than on poor ones, but ergosterol content in those yeast cells is relatively lower. Ergosterol content, one of the most variable parameters in ergosterol production by yeast cultivation, is greatly influenced by nitrogen limitation. The aim of our work was to study how the nitrogen sources affected the membrane ergosterol content and increase the total ergosterol yield. On the premise of keeping high ergosterol content in yeast cell, the ergosterol yield was enhanced by increasing the yeast biomass. Direct feed back control of glucose using an on-line ethanol concentration monitor was introduced to achieve high cell density. Ammonia, which acted as nitrogen source, was added to adjust pH during fermentation process, but its addition needed careful control. Cultivation in 5 L bioreactor was carried out under following conditions: culture temperature 30+/-1 degrees C, pH 5.5+/-0.1, agitation speed 600 rpm, controlling ethanol concentration below 1% and controlling ammonium ion concentration below 0.1 mol/L. Under these conditions the yeast dry weight reached 95.0+/-2.6 g/L and the ergosterol yield reached 1981+/-34 mg/L. PMID:16488499

  1. Removal of carbonaceous and nitrogenous pollutants from a synthetic wastewater using a membrane-coupled bioreactor.

    Science.gov (United States)

    Ghosh, Sudeshna; LaPara, Timothy M

    2004-09-01

    Two modified Ludzack-Ettinger (MLE)-type membrane-coupled bioreactors (MBRs) were investigated in this study for the purpose of removing both nitrogenous and carbonaceous pollutants from a synthetic wastewater. During the first MBR experiment, removal efficiencies were high (>90%) for chemical oxygen demand (COD) and ammonia, but total nitrogenous pollutant removal efficiency was poor (approximately 25%). Bacterial community analysis of ammonia oxidizing bacteria (AOB) by a nested PCR-DGGE approach detected two Nitrosomonas-like populations and one Nitrosospira-like population. During the initial portion of the second MBR experiment, COD and ammonia removal efficiencies were similar to the first MBR experiment until the COD of the influent wastewater was increased to provide additional electron donors to support denitrification. Total nitrogen removal efficiencies eventually exceeded 90%, with a hydraulic residence time (HRT) of 24 h and a recirculation ratio of 8. When the HRT of the MBR experiment was decreased to 12 h, however, ammonia removal efficiency was adversely affected. A subsequent increase in the HRT to 18 h helped improve removal efficiencies for both ammonia (>85%) and total nitrogenous compounds (approximately 70%). Our research demonstrates that MBRs can be effectively designed to remove both carbonaceous and nitrogenous pollutants. The ability of the microbial community to switch between anoxic (denitrifying) and oxic (nitrifying) conditions, however, represents a critical process constraint for the application of MLE-type MBR systems, such that little benefit is gained compared to conventional designs. PMID:15338423

  2. Dynamic strain ageing of deformed nitrogen-alloyed AISI 316 stainless steels

    International Nuclear Information System (INIS)

    Intergranular stress corrosion cracking has occurred in BWR environment in non-sensitized, deformed austenitic stainless steel materials. The affecting parameters are so far not fully known, but deformation mechanisms may be decisive. The effect of deformation and nitrogen content on the behaviour of austenitic stainless steels was investigated. The materials were austenitic stainless steels of AISI 316L type with different amounts of nitrogen (0.03 - 0.18%) and they were mechanically deformed 0, 5 and 20%. The investigations are focused on the dynamic strain ageing (DSA) behaviour. A few crack growth rate measurements are performed on nuclear grade AISI 316NG material with different degrees of deformation (0, 5 and 20%). The effects of DSA on mechanical properties of these materials are evaluated based on peaks in ultimate tensile strength and strain hardening coefficient and minimum in ductility in the DSA temperature range. Additionally, internal friction measurements have been performed in the temperature range of -100 to 600 deg. C for determining nitrogen interactions with other alloying elements and dislocations (cold-worked samples). The results show an effect of nitrogen on the stainless steel behaviour, e.g. clear indications of dynamic strain ageing and changes in the internal friction peaks as a function of nitrogen content and amount of deformation. (authors)

  3. Hydrogen effects in nitrogen-alloyed austenitic steels; Wirkung von Wasserstoff in stickstofflegierten austenitischen Staehlen

    Energy Technology Data Exchange (ETDEWEB)

    Uhlemann, M.; Mummert, K. [Institut fuer Festkoerper- und Werkstofforschung Dresden e.V. (Germany); Shehata, M.F. [National Research Centre, Cairo (Egypt)

    1998-12-31

    Hydrogen increases the yield strength of nitrogen-alloyed steels, but on the other hand adversely affects properties such as tensile strength and elongation to fracture. The effect is enhanced with increasing nitrogen and hydrogen contents. Under the effect of hydrogen addition, the discontinuous stress-strain characteristic and the distinct elongation limit of hydrogen-free, nitrogen containing steels is no longer observed in the material. This change of mechanical properties is attributed to an interatomic interaction of nitrogen and hydrogen in the lattice, which is shown for instance by such effects as reduction of hydrogen velocity, high solubility, and a particularly strong lattice expansion. The nature of this interaction of nitrogen and hydrogen in the fcc lattice remains to be identified. (orig./CB) [Deutsch] Wasserstoff fuehrt in stickstofflegierten Staehlen zu einer Erhoehung der Streckgrenze, aber gleichzeitig zu einer Abnahme der Zugfestigkeit und Bruchdehnung. Dieser Effekt verstaerkt sich mit zunehmenden Stickstoff- und Wasserstoffgehalten. Ein diskontinuierlicher Spannungs-Dehnungsverlauf mit einer ausgepraegten Streckgrenze in wasserstofffreien hochstickstoffhaltigen Staehlen wird nach Wasserstoffeinfluss nicht mehr beobachtet. Die Aenderung der mechanischen Eigenschaften, wird auf eine interatomare Wechselwirkung von Stickstoff und Wasserstoff im Gitter zurueckgefuehrt, die sich u.a. in geringer Wasserstoffdiffusionsgeschwindigkeit, hoher Loeslichkeit und vor allem in extremer Gitteraufweitung aeussert. Insgesamt ist die Natur der Wechselwirkung zwischen Stickstoff und Wasserstoff im kfz Gitter noch nicht aufgeklaert. (orig.)

  4. Cyanobacteria in CELSS: Growth strategies for nutritional variation and nitrogen cycling

    Science.gov (United States)

    Fry, I. V.; Packer, L.

    1990-01-01

    Cyanobacteria (blue-green algae) are versatile organisms which are capable of adjusting their cellular levels of carbohydrate, protein, and lipid in response to changes in the environment. Under stress conditions there is an imbalance between nitrogen metabolism and carbohydrate/lipid synthesis. The lesion in nitrogen assimilation is at the level of transport: the stress condition diverts energy from the active accumulation of nitrate to the extrusion of salt, and probably inhibits a cold-labile ATP'ace in the case of cold shock. Both situations affect the bioenergetic status of the cell such that the nitrogenous precursors for protein synthesis are depleted. Dispite the inhibition of protein synthesis and growth, photosynthetic reductant generation is relatively unaffected. The high O2 reductant would normally lead to photo-oxidative damage of cellular components; however, the organism copes by channeling the 'excess' reductant into carbon storage products. The increase in glycogen (28 to 35 percent dry weight increase) and the elongation of lipid fatty acid side chains (2 to 5 percent dry weight increase) at the expense of protein synthesis (25 to 34 percent dry weight decrease) results in carbohydrate, lipid and protein ratios that are closer to those required in the human diet. In addition, the selection of nitrogen fixing mutants which excrete ammonium ions present an opportunity to tailor these micro-organisms to meet the specific need for a sub-system to reverse potential loss of fixed nitrogen material.

  5. Impact of photosynthesis and transpiration on nitrogen removal in constructed wetlands

    Institute of Scientific and Technical Information of China (English)

    LUO Weiguo; WANG Shihe; HUANG Juan; YAN Lu; HUANG Jun

    2007-01-01

    To determine the impact of photosynthesis and transpiration on nitrogen removal in wetlands,an artificial wetland planted with reeds was constructed to treat highly concentrated domestic wastewater.Under different meteorological and hydraulic conditions,the daily changes of photosynthesis and transpiration of reeds,as well as nitrogen removal efficiency were measured.It was found that net photosynthesis rate per unit leaf area was maintained on a high Photon Flux Density was high during the day.Meanwhile,TN and NH4+-N removal efficiency rose to 79.6% and 89.6%,respectively-the maximum values observed in the test.Correlation coefficient analysis demonstrated a positive correlation among photon flux density,net photosynthetic rate,transpiration rate,and TN and NH4+-N removal efficiency.In contrast,there was a negative correlation between stomatal conductance and TN and NH4+-N removal efficiency.Results suggest that the photosynthesis and transpiration of wetland plants have a great impact on nitrogen removal efficiency of wetlands,which can be enhanced by an increase in the photosynthesis and transpiration rate.In addition,the efficiency of water usage by reeds and nitrogen removal efficiency could be affected by the water level in wetlands;a higher level boosts nitrogen removal efficiency.

  6. Dynamic strain ageing of deformed nitrogen-alloyed AISI 316 stainless steels

    Energy Technology Data Exchange (ETDEWEB)

    Ehrnsten, U.; Toivonen, A. [Materials and Structural Integrity, VTT Technical Research Centre of Finland, Kemistintie 3, P.O. Box 1704, FIN-02044 VTT (Finland); Ivanchenko, M.; Nevdacha, V.; Yagozinskyy, Y.; Haenninen, H. [Department of Mechanical Engineering, Helsinki University of Technology Puumiehenkuja 3, P.O. Box 4200, FIN-02015 HUT (Finland)

    2004-07-01

    Intergranular stress corrosion cracking has occurred in BWR environment in non-sensitized, deformed austenitic stainless steel materials. The affecting parameters are so far not fully known, but deformation mechanisms may be decisive. The effect of deformation and nitrogen content on the behaviour of austenitic stainless steels was investigated. The materials were austenitic stainless steels of AISI 316L type with different amounts of nitrogen (0.03 - 0.18%) and they were mechanically deformed 0, 5 and 20%. The investigations are focused on the dynamic strain ageing (DSA) behaviour. A few crack growth rate measurements are performed on nuclear grade AISI 316NG material with different degrees of deformation (0, 5 and 20%). The effects of DSA on mechanical properties of these materials are evaluated based on peaks in ultimate tensile strength and strain hardening coefficient and minimum in ductility in the DSA temperature range. Additionally, internal friction measurements have been performed in the temperature range of -100 to 600 deg. C for determining nitrogen interactions with other alloying elements and dislocations (cold-worked samples). The results show an effect of nitrogen on the stainless steel behaviour, e.g. clear indications of dynamic strain ageing and changes in the internal friction peaks as a function of nitrogen content and amount of deformation. (authors)

  7. The Effects of Mineral Nitrogen on the Fixation of Atmospheric Nitrogen by Vicia Faba L

    International Nuclear Information System (INIS)

    From 1964 to 1966 a systematic research vas carried out at the Central Research Institute for Plant Production in Prague - Ruzyně, aimed at examining the effect of gradually increased levels of nitrogen and various forms of nitrogen in nitrogen fertilizers on the yield, nitrogen content and the nodulation of the roots of horse bean (Vicia faba LQ. By means of 15N, the proportion of the total nitrogen content of the plant derived from the fertilizer as well as the total utilization of the nitrogen fertilizer by the plant were determined. The experiments were carried out in a series of greenhouse pot tests using a brown soil type, with ammonium sulphate and potassium nitrate as the nitrogen sources. Gradually-increased-levels of nitrogen in ammonium sulphate (0, 5.2, 26.2, 52.5 and 105.0 mgN/kg of soil) applied to the horse bean did not exert any substantial effect on the yield of fresh aerial parts of the horse bean, when harvested at the flowering period. The nitrogen content of tissues of the fertilized plants differed from the control plants (without nitrogen addition) only at the highest nitrogen level (2.7% compared to 3.4% N). The proportion of nitrogen absorbed from the nitrogen fertilizer by whole plant, increased almost as a linear function of nitrogen supplied. Thus the whole plant consumed 51 to 57% of the nitrogen from the first two fertilizer levels, and 64 to 69% from the last two levels of fertilizer, the 52.5-mg and 105-mg levels. In comparing nitrogen supplied as potassium nitrate with nitrogen in ammonium sulphate, at a level of 26.2 mg N/kg of soil, no difference of yield and of percentage nitrogen content in the aerial part of horse bean was found between the plants grown with the nitrogen fertilizers and control plants. The isotopical analysis of nitrogen showed that in the aerial part of horse bean plant the percentage proportion of nitrogen deriving from the fertilizer was higher when potassium nitrate was used (10.8%), than in case of

  8. Isolation and characterization of a mutant defective in triacylglycerol accumulation in nitrogen-starved Chlamydomonas reinhardtii.

    Science.gov (United States)

    Hung, Chun-Hsien; Kanehara, Kazue; Nakamura, Yuki

    2016-09-01

    Triacylglycerol (TAG), a major source of biodiesel production, accumulates in nitrogen-starved Chlamydomonas reinhardtii. However, the metabolic pathway of starch-to-TAG conversion remains elusive because an enzyme that affects the starch degradation is unknown. Here, we isolated a new class of mutant bgal1, which expressed an overaccumulation of starch granules and defective photosynthetic growth. The bgal1 was a null mutant of a previously uncharacterized β-galactosidase-like gene (Cre02.g119700), which decreased total β-galactosidase activity 40% of the wild type. Upon nitrogen starvation, the bgal1 mutant showed decreased TAG accumulation mainly due to the reduced flux of de novo TAG biosynthesis evidenced by increased unsaturation of fatty acid composition in TAG and reduced TAG accumulation by additional supplementation of acetate to the culture media. Metabolomic analysis of the bgal1 mutant showed significantly reduced levels of metabolites following the hydrolysis of starch and substrates for TAG accumulation, whereas metabolites in TCA cycle were unaffected. Upon nitrogen starvation, while levels of glucose 6-phosphate, fructose 6-phosphate and acetyl-CoA remained lower, most of the other metabolites in glycolysis were increased but those in the TCA cycle were decreased, supporting TAG accumulation. We suggest that BGAL1 may be involved in the degradation of starch, which affects TAG accumulation in nitrogen-starved C. reinhardtii. This article is part of a Special Issue entitled: Plant Lipid Biology edited by Kent D. Chapman and Ivo Feussner. PMID:27060488

  9. [Vertical Distribution Characteristics of Typical Forest Soil Organic Nitrogen in Dawei Mountain].

    Science.gov (United States)

    Ding, Xian-qing; Ma, Hui-jing; Zhu, Xiao-long; Chen, Shan; Hou, Hong-bo; Peng, Pei-qin

    2015-10-01

    To clarify altitudinal gradient of subtropical forest soil total nitrogen and organic nitrogen, soil samples were collected per 10 cm on soil profile (0-100 cm) in Dawei Mountain, researched the variation of soil organic nitrogen and correlation with soil physical and chemical properties. The results showed that: (1) Total nitrogen, acid hydrolysable organic nitrogen and soluble organic nitrogen decreased with the increase of depth, content of each component in mountain granite yellow-brown soils was much higher affected by altitude; (2) The average percentage of soil organic nitrogen to total nitrogen was 97.39% ± 1.17%, and soil acid hydrolysable organic nitrogen was 64.38% ± 10.68%, each component decreased with the increase of soil depth; (3) Soil soluble organic nitrogen content was 9.92- 23.45 mg x kg(-1), free amino acids (1.62 - 12.02 mg x kg(-1)) accounted for about 27.36% ± 9.95% of soluble organic nitrogen; (4) Soil acid hydrolysable organic nitrogen and soluble organic nitrogen were significantly positively correlated with total nitrogen, total soluble nitrogen and inorganic nitrogen (P soil bulk density, organic carbon, and total phosphorus (P soil nitrogen in typical subtropical forest, each component showed a downward trend increase with soil depth affected by altitude and soil physical and chemical properties. There was a close conversion relationship between soil organic nitrogen and other nitrogen forms, the characteristics of soil organic nitrogen will have profound impact on nitrogen cycling of forest ecological system. PMID:26841616

  10. Nitrogen pollution: an assessment of its threat to amphibian survival.

    OpenAIRE

    Rouse, J D; Bishop, C A; Struger, J

    1999-01-01

    The potential for nitrate to affect amphibian survival was evaluated by examining the areas in North America where concentrations of nitrate in water occur above amphibian toxicity thresholds. Nitrogen pollution from anthropogenic sources enters bodies of water through agricultural runoff or percolation associated with nitrogen fertilization, livestock, precipitation, and effluents from industrial and human wastes. Environmental concentrations of nitrate in watersheds throughout North America...

  11. Study of total dry matter and protein extraction from canola meal as affected by the pH, salt addition and use of zeta-potential/turbidimetry analysis to optimize the extraction conditions.

    Science.gov (United States)

    Gerzhova, Alina; Mondor, Martin; Benali, Marzouk; Aider, Mohammed

    2016-06-15

    Total dry matter and proteins were differentially and preferentially extracted from canola meal (CM) under different conditions. The effect of the extraction medium pH, CM concentration and salt concentrations were found to have different influences on the extractability of total dry matter and proteins from CM. The pH of the extracting medium had the most significant effect. The maximal total dry matter (42.8±1.18%) extractability was obtained with 5% CM at pH 12 without salt addition, whereas the maximal for total protein (58.12±1.47%) was obtained with 15% CM under the same conditions. The minimal extractability for the dry matter (26.63±0.67%) was obtained with 5% CM at pH 10 without salt added and the minimal protein extractability was observed in a 10% CM at pH 10, in 0.01 NaCl. Turbidity and ζ-potential measurements indicated that pH 5 was the optimum condition for the highest protein extraction yield. SDS-PAGE analysis showed that salt addition contributes to higher solubility of canola proteins specifically cruciferin fraction, although it reduces napin extraction. PMID:26868572

  12. Nitrogen in Interplanetary Dust Particles

    Science.gov (United States)

    Keller, L. P.; Thomas, K. L.; Bradley, J. P.; McKay, D. S.

    1995-09-01

    SEM/EDX analysis of L2011R11 shows that it has a bulk C abundance of ~9 wt.% (nearly 3X the CI abundance), which indicates that, for this particle, the absolute N abundance is also enriched above CI levels. EELS is well-suited for this analysis because of its sensitivity for light element detection and quantification, and also for the additional data on bonding environment that can be deduced from the near-edge structure. References: [1] Stadermann F. J. et al. (1989) Meteoritics, 24, 327. [2] Stadermann F. J. et al. (1990) LPS XXI, 1190. [3] Messenger S. et al., this volume. [4] Clemett S. J. et al. (1993) Science, 262, 721. [5] Kerridge J. F. (1985) GCA, 49, 1707. [6] Fomenkova M. N. et al. (1994) GCA, 58, 4503. [7] Bradley J. P. et al. (1993) LPS XXIV, 173. [8] Anders E. and Grevesse N. (1989) GCA, 53, 197. FIGURE 1. Electron energy-loss data from carbonaceous material in L2011R11 (a pyroxene-rich, anhydrous IDP) showing detectable nitrogen associated with carbon. The lower spectrum is a 2nd difference spectrum of the raw data.

  13. Competition in a rice - cowpea intercrop as affected by nitrogen fertilizer and plant population Competição em uma cultura consorciada de arroz-guandu em função do fertilizante nitrogenado e da densidade populacional de plantas

    Directory of Open Access Journals (Sweden)

    Frank Oke Oroka

    2007-12-01

    Full Text Available The increased productivity or yield advantage provided by intercropping is attributed to a better use of resources by crops grown in mixtures, as compared to the same species grown in sole stands. In an intercropping system with upland rice and cowpea, the intra and inter-competition was quantified, as affected by plant population density and rate of nitrogen. Reductions in number of panicles per rice plant and number of grains per panicle were obtained with high density in both sole and mixture rice populations. Increasing nitrogen rate did not affect yield and yield components in both populations, but number and weight of pods per plant of cowpea in sole stands increased. Land equivalent ratios exceeding unity were obtained, indicating an improved resource use by the crop mixture. Relative crowding coefficient and aggressivity indices showed cowpea to be the dominant crop, with rice being dominated. Nitrogen utilization efficiency was high with intercrops, but was generally poor in stands of high population density.O aumento em produtividade devido a plantios consorciados é atribuído ao melhor uso dos recursos presentes pelas plantas em desenvolvimento conjunto, em comparação às mesmas espécies crescendo em dosséis separados. Em um sistema consorciado de arroz e guandu quantificou-se as inter- e intra competições em relação à densidade populacional e taxa de aplicação de nitrogênio. Reduções significativas do número de panículas por planta de arroz e número de grãos por panícula foram observados para alta densidade, tanto para culturas solteira de arroz como em populações mistas. O aumento das doses de nitrogênio não afetou a produção e os componentes de produção em ambos os sistemas, ao passo que o número e peso de vagens por planta do guandu aumentaram em culturas solteiras. Foram obtidas razões de área equivalente maiores que a unidade, mostrando melhoria no uso da terra nas culturas mistas. O coeficiente

  14. Biofilm activity and sludge characteristics affected by exogenous N-acyl homoserine lactones in biofilm reactors.

    Science.gov (United States)

    Hu, Huizhi; He, Junguo; Liu, Jian; Yu, Huarong; Zhang, Jie

    2016-07-01

    This study verified the effect of N-acyl homoserine lactone (AHL) concentrations on mature biofilm systems. Three concentrations of an AHL mixture were used in the batch test. Introducing of 5nM AHLs significantly increased biofilm activity and increased sludge characteristics, which resulted in better pollutant removal performance, whereas exogenous 50nM and 500nM AHLs limited pollutant removal, especially COD and nitrogen removal. To further identify how exogenous signal molecular affects biofilm system nitrogen removal, analyzing of nitrifying bacteria through real-time polymerase chain reaction (RT-PCR) revealed that these additional signal molecules affect nitrifying to total bacteria ratio. In addition, the running state of the system was stable during 15days of operation without an AHL dose, which suggests that the changes in the system due to AHL are irreversible. PMID:27030953

  15. Assessment of free-living nitrogen fixing microorganisms for commercial nitrogen fixation

    Energy Technology Data Exchange (ETDEWEB)

    Stokes, B.O.; Wallace, C.J.

    1978-08-01

    Ammonia production by Klebsiella pneumoniae is not economical with present strains and improving nitrogen fixation to its theoretical limits in this organism is not sufficient to achieve economic viability. Because the value of both the hydrogen produced by this organism and the methane value of the carbon source required greatly exceed the value of the ammonia formed, ammonia (fixed nitrogen) should be considered the by-product. The production of hydrogen by Klebsiella or other anaerobic nitrogen fixers should receive additional study, because the activity of nitrogenase offers a significant improvement in hydrogen production. The production of fixed nitrogen in the form of cell mass by Azotobacter is also uneconomical and the methane value of the carbon substrate exceeds the value of the nitrogen fixed. Parametric studies indicate that as efficiencies approach the theoretical limits the economics may become competitive. The use of nif-derepressed microorganisms, particularly blue-green algae, may have significant potential for in situ fertilization in the environment.

  16. Transcriptional Response of Saccharomyces cerevisiae to Different Nitrogen Concentrations during Alcoholic Fermentation▿ †

    OpenAIRE

    Mendes-Ferreira A; Olmo Muñoz, Marcel·lí del; García Martínez, José; Jiménez Martí, Elena; Mendes-Faia A; Pérez Ortín, José Enrique; Leão C.

    2007-01-01

    Gene expression profiles of a wine strain of Saccharomyces cerevisiae PYCC4072 were monitored during alcoholic fermentations with three different nitrogen supplies: (i) control fermentation (with enough nitrogen to complete sugar fermentation), (ii) nitrogen-limiting fermentation, and (iii) the addition of nitrogen to the nitrogen-limiting fermentation (refed fermentation). Approximately 70% of the yeast transcriptome was altered in at least one of the fermentation stages studied, revealing t...

  17. Nitrogen trading tool

    Science.gov (United States)

    The nitrogen cycle is impacted by human activities, including those that increase the use of nitrogen in agricultural systems, and this impact can be seen in effects such as increased nitrate (NO3) levels in groundwater or surface water resources, increased concentration of nitrous oxide (N2O) in th...

  18. Nitrogen use efficiency (NUE)

    NARCIS (Netherlands)

    Oenema, O.

    2015-01-01

    There is a need for communications about resource use efficiency and for measures to increase the use efficiency of nutrients in relation to food production. This holds especially for nitrogen. Nitrogen (N) is essential for life and a main nutrient element. It is needed in relatively large quantitie

  19. Improvement of Nitrogen Assimilation and Fermentation Kinetics under Enological Conditions by Derepression of Alternative Nitrogen-Assimilatory Pathways in an Industrial Saccharomyces cerevisiae Strain

    OpenAIRE

    Salmon, Jean-Michel; Barre, Pierre

    1998-01-01

    Metabolism of nitrogen compounds by yeasts affects the efficiency of wine fermentation. Ammonium ions, normally present in grape musts, reduce catabolic enzyme levels and transport activities for nonpreferred nitrogen sources. This nitrogen catabolite repression severely impairs the utilization of proline and arginine, both common nitrogen sources in grape juice that require the proline utilization pathway for their assimilation. We attempted to improve fermentation performance by genetic alt...

  20. Analyzing the Distribution and Chemical Evolution of Major Nitrogen Carriers within Protoplanetary Disks

    Science.gov (United States)

    Pegues, Jamila; Oberg, Karin

    2016-01-01

    Nitrogen is an important component in many of the world's known organic and inorganic compounds, and its presence is crucial for the existence and survival of life as we know it on Earth today. And yet, in comparison to the total amount of nitrogen available, nitrogen exists as a depleted resource throughout the Solar System, with Earth and unearthed meteorites featuring nitrogen levels depleted from 1 to 5 orders of magnitude relative to the Sun. Additionally, comets have been discovered that contain depleted levels of N2 in comparison to CO, despite the similar binding strengths of both N2 and CO to ices, with ices functioning as the main component in comets.Mechanisms that are likely to play a major part in the distribution of nitrogen throughout the Solar System, and other extra-solar systems, are condensation fronts, such as snowlines and snowsurfaces. Here, condensation fronts refer to the locations at which 50% of a given volatile is contained in gaseous form, while the other 50% is contained within grain form. During formation, astronomical bodies will accumulate different chemical compositions, depending upon where they form with respect to the locations of the condensation fronts within the system. In addition, a system's initial chemistry, as well as how that chemistry evolves, will ultimately alter how the volatiles in the system are distributed over time.Thus, the locations of these condensation fronts, coupled with a protoplanetary disk's initial chemistry and chemical evolution, are mechanisms that affect the eventual distribution and evolution of the disk's volatiles. In this project, we characterize and interpret these mechanisms within disk models. We vary the disk's time dependence and initial chemical conditions, and then analyze the effects of those variations upon the main carriers of nitrogen in both gaseous and grain form. From observed patterns and characteristics of these varied models, we evolve our understanding of curious nitrogen

  1. Euthanasia of Small Animals with Nitrogen; Comparison with Intravenous Pentobarbital

    OpenAIRE

    Quine, John P; Buckingham, William; Strunin, Leo

    1988-01-01

    Intravenous pentobarbital (with or without addition of saturated potassium chloride) was compared with nitrogen gas exposure for euthanasia of small animals (dogs, cats, and rabbits) in a humane society environment. Initially, electrocardiographic) and electroencephalographic monitoring were used to establish the time of death in presedated animals given either pentobarbital or exposed to nitrogen; later, nitrogen euthanasia alone was studied. Sedation with acepromazine delayed the effects of...

  2. The nitrogen cycle.

    Science.gov (United States)

    Stein, Lisa Y; Klotz, Martin G

    2016-02-01

    Nitrogen is the fourth most abundant element in cellular biomass, and it comprises the majority of Earth's atmosphere. The interchange between inert dinitrogen gas (N2) in the extant atmosphere and 'reactive nitrogen' (those nitrogen compounds that support, or are products of, cellular metabolism and growth) is entirely controlled by microbial activities. This was not the case, however, in the primordial atmosphere, when abiotic reactions likely played a significant role in the inter-transformation of nitrogen oxides. Although such abiotic reactions are still important, the extant nitrogen cycle is driven by reductive fixation of dinitrogen and an enzyme inventory that facilitates dinitrogen-producing reactions. Prior to the advent of the Haber-Bosch process (the industrial fixation of N2 into ammonia, NH3) in 1909, nearly all of the reactive nitrogen in the biosphere was generated and recycled by microorganisms. Although the Haber-Bosch process more than quadrupled the productivity of agricultural crops, chemical fertilizers and other anthropogenic sources of fixed nitrogen now far exceed natural contributions, leading to unprecedented environmental degradation. PMID:26859274

  3. The Effect of Nutritional Conditions on Root Metabolism and the Quantitative and Qualitative Composition of Nitrogenous Compounds Translocated from the Roots to the Aerial Parts of Plants

    International Nuclear Information System (INIS)

    Experiments were carried out with maize cultivated under normal conditions of nutrition and under conditions of nitrogen and phosphorus deficiency. The results obtained show that a deficiency of these elements has a very marked effect on root metabolic processes connected with the uptake, conversion and translocation of nitrogen. Under conditions of nitrogen deficiency the amount of amino acids translocated from the roots to the aerial parts of the plant drops sharply. This is accompanied by a marked change in the qualitative composition of the amino acids, which ultimately affects the operation of the synthesizing mechanism of the aerial organs. After addition of nitrogen to 30-day maize plants, rapid amino acid synthesis in the roots was observed, and the amount of free amino acids translocated from the roots to the aerial parts increased by a factor of 12 in the two hours following addition of the nitrogen. With the use of 15N , introduced into the nutrient medium as ammonium nitrate and calcium nitrate, it was found that the nitrogen taken up by the roots was preferentially incorporated into the amino acids and amides originating from the ketonic acids of the Krebs cycle. O f the total amount of amino acids translocated from the roots to the aerial parts, more than 50 % was accounted for by glutamine, alanine and aspartic acid. The results obtained give grounds for believing that variations in the conditions of nutrition affect the nitrogen metabolism of plants mainly through the metabolism of nitrogenous substances in the roots. The paper contains the following tables: 1. Concentration of different nitrogen fractions in maize exudate; 2. Increase in the concentration of amino acids in maize exudate 24 hours after the addition of nitrogen to the P K variety; 3. Effect of nutritional conditions on the concentration of different nitrogen fractions in maize exudate during vegetation; 4. Effect of nutritional conditions on the concentration of different free amino

  4. Resolving the influence of nitrogen abundances on sediment organic matter in macrophyte-dominated lakes, using fluorescence spectroscopy

    Institute of Scientific and Technical Information of China (English)

    Xin Yao; Shengrui Wang; Lixin Jiao; Caihong Yan; Xiangcan Jin

    2015-01-01

    A controlled experiment was designed to resolve the influence of nitrogen abundance on sediment organic matters in macrophyte-dominated lakes using fluorescence analysis.Macrophyte biomass showed coincident growth trends with time,but different variation rates with nitrogen treatment.All plant growth indexes with nitrogen addition (N,NH4Cl 100,200,400 mg/kg,respectively) were lower than those of the control group.Four humiclike components,two autochthonous tryptophan-like components,and one autochthonous tyrosine-like component were identified using the parallel factor analysis model.The results suggested that the relative component changes of fluorescence in the colonized sediments were in direct relation to the change of root biomass with time.In the experiment,the root formation parameters of the plants studied were significantly affected by adding N in sediments,which may be related to the reason that the root growth was affected by N addition.Adding a low concentration of N to sediments can play a part in supplying nutrients to the plants.However,the intensive uptake of NH~ may result in an increase in the intracellular concentration of ammonia,which is highly toxic to the plant cells.Hence,our experiment results manifested that organic matter cycling in the macrophyte-dominated sediment was influenced by nitrogen enrichment through influencing vegetation and relevant microbial activity.

  5. Evolution of Photosynthesis and Biospheric Oxygenation Contingent Upon Nitrogen Fixation?

    CERN Document Server

    Grula, J W

    2006-01-01

    How photosynthesis by Precambrian cyanobacteria oxygenated Earth's biosphere remains incompletely understood. Here it is argued that the oxic transition, which took place between approximately 2.3 and 0.5 Gyr ago, required a great proliferation of cyanobacteria, and this in turn depended on their ability to fix nitrogen via the nitrogenase enzyme system. However, the ability to fix nitrogen was not a panacea, and the rate of biospheric oxygenation may still have been affected by nitrogen constraints on cyanobacterial expansion. Evidence is presented for why cyanobacteria probably have a great need for fixed nitrogen than other prokaryotes, underscoring the importance of their ability to fix nitrogen. The connection between nitrogen fixation and the evolution of photosynthesis is demonstrated by the similarities between nitrogenase and enzymes critical for the biosynthesis of (bacterio)chlorophyll. It is hypothesized that biospheric oxygenation would not have occurred if the emergence of cyanobacteria had not ...

  6. A nitrogen mass balance for California

    Science.gov (United States)

    Liptzin, D.; Dahlgren, R. A.

    2010-12-01

    Human activities have greatly altered the global nitrogen cycle and these changes are apparent in water quality, air quality, ecosystem and human health. However, the relative magnitude of the sources of new reactive nitrogen and the fate of this nitrogen is not well established. Further, the biogeochemical aspects of the nitrogen cycle are often studied in isolation from the economic and social implications of all the transformations of nitrogen. The California Nitrogen Assessment is an interdisciplinary project whose aim is evaluating the current state of nitrogen science, practice, and policy in the state of California. Because of the close proximity of large population centers, highly productive and diverse agricultural lands and significant acreage of undeveloped land, California is a particularly interesting place for this analysis. One component of this assessment is developing a mass balance of nitrogen as well as identifying gaps in knowledge and quantifying uncertainty. The main inputs of new reactive nitrogen to the state are 1) synthetic nitrogen fertilizer, 2) biological nitrogen fixation, and 3) atmospheric nitrogen deposition. Permanent losses of nitrogen include 1) gaseous losses (N2, N2O, NHx, NOy), 2) riverine discharge, 3) wastewater discharge to the ocean, and 4) net groundwater recharge. A final term is the balance of food, feed, and fiber to support the human and animal populations. The largest input of new reactive nitrogen to California is nitrogen fertilizer, but both nitrogen fixation and atmospheric deposition contribute significantly. Non-fertilizer uses, such as the production of nylon and polyurethane, constitutes about 5% of the synthetic N synthesized production. The total nitrogen fixation in California is roughly equivalent on the 400,000 ha of alfalfa and the approximately 40 million ha of natural lands. In addition, even with highly productive agricultural lands, the large population of livestock, in particular dairy cows

  7. Nitrous oxide and methane fluxes in south Brazilian gleysol as affected by nitrogen fertilizers Fluxos de óxido nitroso e de metano em gleissolo influenciados pela aplicação de fertilizantes nitrogenados no sul do Brasil

    Directory of Open Access Journals (Sweden)

    Josiléia Acordi Zanatta

    2010-10-01

    Full Text Available Nitrogen fertilizers increase the nitrous oxide (N2O emission and can reduce the methane (CH4 oxidation from agricultural soils. However, the magnitude of this effect is unknown in Southern Brazilian edaphoclimatic conditions, as well as the potential of different sources of mineral N fertilizers in such an effect. The aim of this study was to investigate the effects of different mineral N sources (urea, ammonium sulphate, calcium nitrate, ammonium nitrate, Uran, controlled- release N fertilizer, and urea with urease inhibitor on N2O and CH4 fluxes from Gleysol in the South of Brazil (Porto Alegre, RS, in comparison to a control treatment without a N application. The experiment was arranged in a randomized block with three replications, and the N fertilizer was applied to corn at the V5 growth stage. Air samples were collected from a static chambers for 15 days after the N application and the N2O and CH4 concentration were determined by gas chromatography. The topmost emissions occurred three days after the N fertilizer application and ranged from 187.8 to 8587.4 µg m-2 h-1 N. The greatest emissions were observed for N-nitric based fertilizers, while N sources with a urease inhibitor and controlled release N presented the smallest values and the N-ammonium and amidic were intermediate. This peak of N2O emissions was related to soil NO3--N (R² = 0.56, p Fertilizantes nitrogenados incrementam os fluxos de óxido nitroso (N2O e podem deprimir a oxidação de metano (CH4 em solos agrícolas. Entretanto, não existem resultados da magnitude desses efeitos nas condições edafoclimáticas do Sul do Brasil, tampouco do potencial de algumas fontes de N em mitigar esses efeitos. O presente estudo objetivou avaliar o impacto da aplicação de fertilizantes nitrogenados (ureia, sulfato de amônio, nitrato de cálcio, nitrato de amônio, Uran, N de liberação lenta e ureia com inibidor de urease nos fluxos de N2O e CH4 em um Gleissolo no Sul do Brasil

  8. Modelling the ecosystem effects of nitrogen deposition: Model of Ecosystem Retention and Loss of Inorganic Nitrogen (MERLIN

    Science.gov (United States)

    Cosby, B. J.; Ferrier, R. C.; Jenkins, A.; Emmett, B. A.; Wright, R. F.; Tietema, A.

    A catchment-scale mass-balance model of linked carbon and nitrogen cycling in ecosystems has been developed for simulating leaching losses of inorganic nitrogen. The model (MERLIN) considers linked biotic and abiotic processes affecting the cycling and storage of nitrogen. The model is aggregated in space and time and contains compartments intended to be observable and/or interpretable at the plot or catchment scale. The structure of the model includes the inorganic soil, a plant compartment and two soil organic compartments. Fluxes in and out of the ecosystem and between compartments are regulated by atmospheric deposition, hydrological discharge, plant uptake, litter production, wood production, microbial immobilization, mineralization, nitrification, and denitrification. Nitrogen fluxes are controlled by carbon productivity, the C:N ratios of organic compartments and inorganic nitrogen in soil solution. Inputs required are: 1) temporal sequences of carbon fluxes and pools- 2) time series of hydrological discharge through the soils, 3) historical and current external sources of inorganic nitrogen; 4) current amounts of nitrogen in the plant and soil organic compartments; 5) constants specifying the nitrogen uptake and immobilization characteristics of the plant and soil organic compartments; and 6) soil characteristics such as depth, porosity, bulk density, and anion/cation exchange constants. Outputs include: 1) concentrations and fluxes of NO3 and NH4 in soil solution and runoff; 2) total nitrogen contents of the organic and inorganic compartments; 3) C:N ratios of the aggregated plant and soil organic compartments; and 4) rates of nitrogen uptake and immobilization and nitrogen mineralization. The behaviour of the model is assessed for a combination of land-use change and nitrogen deposition scenarios in a series of speculative simulations. The results of the simulations are in broad agreement with observed and hypothesized behaviour of nitrogen dynamics in

  9. NITROGEN UTILIZATION BY DAIRY GOATS OFFERED DIFFERENT NITROGEN SOURCES AS SUPPLEMENTS IN HIGH ISOCALORIC ENERGY CONCENTRATES

    OpenAIRE

    A. R. S. Asih; K. G. Wiryawan; Young, B. A.

    2011-01-01

    Twelve growing female goats (Anglo-Nubian) were assigned to a multiple latin square design experiment to evaluate the effectiveness of additions of nitrogen (N) supplements to a high isocaloric energy ration on N utilization. In this experiment, microbial synthesis and N balance were assessed. The daily rations were either unsupplemented barley meal (BM), or BM supplemented with one of three nitrogen sources. All rations were isocaloric (3.0 Mcal ME/kg DM) and the N supplements were soybean m...

  10. Food, Feed and Fuel: a Story About Nitrogen

    Science.gov (United States)

    Galloway, J. N.; Burke, M. B.; Mooney, H. A.; Steinfeld, H.

    2008-12-01

    Humans obtain metabolic energy by eating food. Nitrogen is required to grow food, but natural supplies of N for human purposes have been inadequate since the beginning of the twentieth century. The Haber-Bosch process now provides a virtually inexhaustible supply of nitrogen, limited primarily by the cost of energy. However, most nitrogen used in food production is lost to the environment, where it cascades through environmental reservoirs contributing to many of the major environmental issues of the day. Furthermore, growing international trade in nitrogen-containing commodities is increasingly replacing wind and water as an important international transporter of nitrogen around the globe. Finally, the rapid growth in crop-based biofuels, and its attendant effects on the global production and trade of all agricultural commodities, could greatly affect global patterns of N use and loss. In the light of the findings above, this paper examines the role of nitrogen in food, feed and fuel production. It describes the beneficial consequences for food production and the negative consequences associated with the commodity nitrogen cascade and the environmental nitrogen cascade. The paper reviews estimates of future projections of nitrogen demands for food and fuel, including the impact of changing diets in the developing world. The paper concludes by presenting the potential interactions among global change, agricultural production and the nitrogen and carbon cycles.

  11. Adição de carbono e nitrogênio e sua relação com os estoques no solo e com o rendimento do milho em sistemas de manejo Carbon and nitrogen addition related to stocks of these elements in soil and corn yield under management systems

    Directory of Open Access Journals (Sweden)

    T. Lovato

    2004-02-01

    relaciona as taxas anuais de adição de C (A e a variação anual nos estoques de COT na camada de 0-0,175 m do solo (dC/dt, que 12,9, 8,1 e 11,5 % do C adicionado ao solo foi retido na matéria orgânica do solo em PD, PR e PC, respectivamente, o que corresponde a uma estimativa aproximada do coeficiente de humificação (k1. Analogamente, estimou-se que 49,7, 21,0 e 33,1 % da quantidade líquida de N adicionada foi retida como NT no solo em PD, PR e PC, respectivamente. A taxa de perda de COT do solo (k2, calculada para a condição dC/dt = zero, foi de 0,0166 ano-1 no solo em PD, 0,0182 ano-1 no solo em PR, e 0,0314 ano-1 no solo em PC. O plantio direto, pela diminuição da taxa de perda de matéria orgânica (k2, e os sistemas de culturas com leguminosas, pela alta adição de C fotossintetizado e de N fixado simbioticamente, são boas alternativas para recuperar os estoques de COT e NT do solo e aumentar o rendimento do milho na região subtropical do Sul do Brasil.Long-term experiments are essential for research about organic matter dynamics of soils. This paper reports results of an experiment installed in September 1985 on a Paleudult soil degraded under inadequate management for 16 years. The experiment was conducted at the Experimental Station of the Federal University of Rio Grande do Sul (Brazil in Eldorado do Sul county. Three soil tillage methods (conventional tillage-CT, reduced tillage-RT and no-tillage-NT, three crop systems (oat/corn-O/C, vetch/corn-V/C and oat + vetch/corn + cowpea-O + V/C + Cp, and two N rates applied to corn as urea (0 and 139 kg ha-1 were tested. A split-plot design arranged in randomized blocks with three replications was used with soil tillage as main plot, the cropping systems as sub-plots and nitrogen rates as sub-blocks. Carbon and nitrogen addition by crops was estimated for the experimental period of 13 years. In September 1998, the soil was sampled in six layers down to 0.30 m depth, and total organic carbon (TOC and total

  12. Modeling nitrogen fluxes in Germany - where does the nitrogen go?

    Science.gov (United States)

    Klement, Laura; Bach, Martin; Breuer, Lutz

    2016-04-01

    According to the latest inventory of the EU Water Framework Directive, 26.3% of German groundwater bodies are in a poor chemical state regarding nitrate. Additionally, the EU initiated infringement proceedings against Germany for not meeting the quality standards of the EU Nitrate Directive. Agriculture has been determined as the main source of nitrate pollution due to over-fertilization and regionally high density of livestock farming. The nitrogen balance surplus is commonly used as an indicator characterizing the potential of nitrate leaching into groundwater bodies and thus also serves as a foundation to introduce legislative restrictions or to monitor the success of mitigation measures. Currently, there is an ongoing discussion which measures are suitable for reducing the risk of nitrate leaching and also to what extent. However, there is still uncertainty about just how much the nitrogen surplus has to be reduced to meet the groundwater quality standards nationwide. Therefore, the aims of our study were firstly to determine the level of the nitrogen surplus that would be acceptable at the utmost and secondly whether the currently discussed target value of 30 kg N per hectare agricultural land for the soil surface nitrogen balance would be sufficient. The models MONERIS (Modeling Nutrient Emissions in River System) and MoRE (Modelling of Regionalized Emissions), the latter based on the first, are commonly used for estimating nitrogen loads into the river system in Germany at the mesoscale, as well as the effect of mitigation measures in the context of the EU directive 2008/105/EC (Environmental quality standards applicable to surface water). We used MoRE to calculate nitrate concentration for 2759 analytical units in Germany. Main factors are the surplus of the soil surface nitrogen balance, the percolation rate and an exponent representing the denitrification in the vadose zone. The modeled groundwater nitrate concentrations did not correspond to the regional

  13. Emiliania Huxleyi (Prymnesiophyceae): Nitrogen-metabolism genes and their expression in response to external nitrogen souces

    DEFF Research Database (Denmark)

    Bruhn, Annette; LaRoche, Julie; Richardson, Katherine

    2010-01-01

    The availability and composition of dissolved nitrogen in ocean waters are factors that influence species composition in natural phytoplankton communities. The same factors affect the ratio of organic to inorganic carbon incorporation in calcifying species, such as the coccolithophore Emiliania...... this study, the complete amino acid sequences for three functional genes involved in nitrogen metabolism in E. huxleyi were identified: a putative formamidase, a glutamine synthetase (GSII family), and assimilatory nitrate reductase. Expression patterns of the three enzymes in cells grown on inorganic...... as well as organic nitrogen sources indicated reduced expression levels of nitrate reductase when cells were grown on NH4+ and a reduced expression level of the putative formamidase when growth was on NO3-. The data reported here suggest the presence of a nitrogen preference hierarchy in E. huxleyi...

  14. Mineral commodity profiles: nitrogen

    Science.gov (United States)

    Kramer, Deborah A.

    2004-01-01

    Overview -- Nitrogen (N) is an essential element of life and a part of all animal and plant proteins. As a part of the DNA and RNA molecules, nitrogen is an essential constituent of each individual's genetic blueprint. As an essential element in the chlorophyll molecule, nitrogen is vital to a plant's ability to photosynthesize. Some crop plants, such as alfalfa, peas, peanuts, and soybeans, can convert atmospheric nitrogen into a usable form by a process referred to as 'fixation.' Most of the nitrogen that is available for crop production, however, comes from decomposing animal and plant waste or from commercially produced fertilizers. Commercial fertilizers contain nitrogen in the form of ammonium and/or nitrate or in a form that is quickly converted to the ammonium or nitrate form once the fertilizer is applied to the soil. Ammonia is generally the source of nitrogen in fertilizers. Anhydrous ammonia is commercially produced by reacting nitrogen with hydrogen under high temperatures and pressures. The source of nitrogen is the atmosphere, which is almost 80 percent nitrogen. Hydrogen is derived from a variety of raw materials, which include water, and crude oil, coal, and natural gas hydrocarbons. Nitrogen-based fertilizers are produced from ammonia feedstocks through a variety of chemical processes. Small quantities of nitrates are produced from mineral resources principally in Chile. In 2002, anhydrous ammonia and other nitrogen materials were produced in more than 70 countries. Global ammonia production was 108 million metric tons (Mt) of contained nitrogen. With 28 percent of this total, China was the largest producer of ammonia. Asia contributed 46 percent of total world ammonia production, and countries of the former U.S.S.R. represented 13 percent. North America also produced 13 percent of the total; Western Europe, 9 percent; the Middle East, 7 percent; Central America and South America, 5 percent; Eastern Europe, 3 percent; and Africa and Oceania

  15. Commercial Nitrogen Fertilizer Purchased

    Data.gov (United States)

    U.S. Environmental Protection Agency — Amounts of fertilizer nitrogen (N) purchased by states in individual years 2003, 2005, 2007, 2009 and 2011, and the % change in average amounts purchased per year...

  16. Effect Of Ferrous Sulfate Supplementation On Digestibility, Nutritive Value And Energy Nitrogen Metabolism In Local Sheep