Relative importance of plant uptake and plant associated denitrification for removal of nitrogen from mine drainage in sub-arctic wetlands.

Science.gov (United States)

Hallin, Sara; Hellman, Maria; Choudhury, Maidul I; Ecke, Frauke

2015-11-15

Reactive nitrogen (N) species released from undetonated ammonium-nitrate based explosives used in mining or other blasting operations are an emerging environmental problem. Wetlands are frequently used to treat N-contaminated water in temperate climate, but knowledge on plant-microbial interactions and treatment potential in sub-arctic wetlands is limited. Here, we compare the relative importance of plant uptake and denitrification among five plant species commonly occurring in sub-arctic wetlands for removal of N in nitrate-rich mine drainage in northern Sweden. Nitrogen uptake and plant associated potential denitrification activity and genetic potential for denitrification based on quantitative PCR of the denitrification genes nirS, nirK, nosZI and nosZII were determined in plants growing both in situ and cultivated in a growth chamber. The growth chamber and in situ studies generated similar results, suggesting high relevance and applicability of results from growth chamber experiments. We identified denitrification as the dominating pathway for N-removal and abundances of denitrification genes were strong indicators of plant associated denitrification activity. The magnitude and direction of the effect differed among the plant species, with the aquatic moss Drepanocladus fluitans showing exceptionally high ratios between denitrification and uptake rates, compared to the other species. However, to acquire realistic estimates of N-removal potential of specific wetlands and their associated plant species, the total plant biomass needs to be considered. The species-specific plant N-uptake and abundance of denitrification genes on the root or plant surfaces were affected by the presence of other plant species, which show that both multi- and inter-trophic interactions are occurring. Future studies on N-removal potential of wetland plant species should consider how to best exploit these interactions in sub-arctic wetlands. Copyright © 2015 Elsevier Ltd. All rights

Improving representation of nitrogen uptake, allocation, and carbon assimilation in the Community Land Model

Science.gov (United States)

Ghimire, B.; Riley, W. J.; Koven, C.

2013-12-01

Nitrogen is the most important nutrient limiting plant carbon assimilation and growth, and is required for production of photosynthetic enzymes, growth and maintenance respiration, and maintaining cell structure. The forecasted rise in plant available nitrogen through atmospheric nitrogen deposition and the release of locked soil nitrogen by permafrost thaw in high latitude ecosystems is likely to result in an increase in plant productivity. However a mechanistic representation of plant nitrogen dynamics is lacking in earth system models. Most earth system models ignore the dynamic nature of plant nutrient uptake and allocation, and further lack tight coupling of below- and above-ground processes. In these models, the increase in nitrogen uptake does not translate to a corresponding increase in photosynthesis parameters, such as maximum Rubisco capacity and electron transfer rate. We present an improved modeling framework implemented in the Community Land Model version 4.5 (CLM4.5) for dynamic plant nutrient uptake, and allocation to different plant parts, including leaf enzymes. This modeling framework relies on imposing a more realistic flexible carbon to nitrogen stoichiometric ratio for different plant parts. The model mechanistically responds to plant nitrogen uptake and leaf allocation though changes in photosynthesis parameters. We produce global simulations, and examine the impacts of the improved nitrogen cycling. The improved model is evaluated against multiple observations including TRY database of global plant traits, nitrogen fertilization observations and 15N tracer studies. Global simulations with this new version of CLM4.5 showed better agreement with the observations than the default CLM4.5-CN model, and captured the underlying mechanisms associated with plant nitrogen cycle.

Contributions of secondary forest and nitrogen dynamics to terrestrial carbon uptake

Directory of Open Access Journals (Sweden)

X. Yang

2010-10-01

Full Text Available We use a terrestrial carbon-nitrogen cycle component of the Integrated Science Assessment Model (ISAM to investigate the impacts of nitrogen dynamics on regrowing secondary forests over the 20th century. We further examine what the impacts of nitrogen deposition and land use change history are on terrestrial carbon uptake since preindustrial time. Our results suggest that global total net land use emissions for the 1990s associated with changes in cropland, pastureland, and wood harvest are 1.22 GtC/yr. Without considering the secondary forest regrowth, the estimated net global total land use emissions are 1.58 GtC/yr or about 0.36 GtC/yr higher than if secondary forest regrowth is considered. Results also show that without considering the nitrogen dynamics and deposition, the estimated global total secondary forest sink for the 1990s is 0.90 GtC/yr or about 0.54 GtC/yr higher than estimates that include the impacts of nitrogen dynamics and deposition. Nitrogen deposition alone is responsible for about 0.13 GtC/yr of the total secondary forest sink. While nitrogen is not a limiting nutrient in the intact primary forests in tropical regions, our study suggests that nitrogen becomes a limiting nutrient for regrowing secondary forests of the tropical regions, in particular Latin America and Tropical Africa. This is because land use change activities, especially wood harvest, removes large amounts of nitrogen from the system when slash is burnt or wood is removed for harvest. However, our model results show that carbon uptake is enhanced in the tropical secondary forests of the Indian region. We argue that this may be due to enhanced nitrogen mineralization and increased nitrogen availability following land use change in the Indian tropical forest ecosystems. Results also demonstrate that there is a significant amount of carbon accumulating in the Northern Hemisphere where most land use changes and forest regrowth has occurred in recent decades

Nitrogen removal from landfill leachate via ex situ nitrification and sequential in situ denitrification

International Nuclear Information System (INIS)

Zhong Qi; Li Daping; Tao Yong; Wang Xiaomei; He Xiaohong; Zhang Jie; Zhang Jinlian; Guo Weiqiang; Wang Lan

2009-01-01

Ex situ nitrification and sequential in situ denitrification represents a novel approach to nitrogen management at landfills. Simultaneous ammonia and organics removal was achieved in a continuous stirred tank reactor (CSTR). The results showed that the maximum nitrogen loading rate (NLR) and the maximum organic loading rate (OLR) was 0.65 g N l -1 d -1 and 3.84 g COD l -1 d -1 , respectively. The ammonia and chemical oxygen demand (COD) removal was over 99% and 57%, respectively. In the run of the CSTR, free ammonia (FA) inhibition and low dissolved oxygen (DO) were found to be key factors affecting nitrite accumulation. In situ denitrification was studied in a municipal solid waste (MSW) column by recalculating nitrified leachate from CSTR. The decomposition of MSW was accelerated by the recirculation of nitrified leachate. Complete reduction of total oxidized nitrogen (TON) was obtained with maximum TON loading of 28.6 g N t -1 TS d -1 and denitrification was the main reaction responsible. Additionally, methanogenesis inhibition was observed while TON loading was over 11.4 g N t -1 TS d -1 and the inhibition was enhanced with the increase of TON loading

Carbon and nitrogen uptake of calcareous benthic foraminifera along a depth-related oxygen gradient in the OMZ of the Arabian Sea

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Annekatrin Julie Enge

2016-02-01

Full Text Available Foraminifera are an important faunal element of the benthos in oxygen-depleted settings such as Oxygen Minimum Zones (OMZs where they can play a relevant role in the processing of phytodetritus. We investigated the uptake of phytodetritus (labeled with 13C and 15N by cal-careous foraminifera in the 0-1 cm sediment horizon under different oxygen concentrations within the OMZ in the eastern Arabian Sea. The in situ tracer experiments were carried out along a depth transect on the Indian margin over a period of 4 to 10 days. The uptake of phy-todetrital carbon within 4 days by all investigated species shows that phytodetritus is a rele-vant food source for foraminifera in OMZ sediments. The decrease of total carbon uptake from 540 to 1100 m suggests a higher demand for carbon by species in the low-oxygen core region of the OMZ or less food competition with macrofauna. Especially Uvigerinids showed high uptake of phytodetrital carbon at the lowest oxygenated site. Variation in the ratio of phytodetrital carbon to nitrogen between species and sites indicates that foraminiferal carbon and nitrogen use can be decoupled and different nutritional demands are found between spe-cies. Lower ratio of phytodetrital carbon and nitrogen at 540 m could hint for greater demand or storage of food-based nitrogen, ingestion or hosting of bacteria under almost anoxic condi-tions. Shifts in the foraminiferal assemblage structure (controlled by oxygen or food availabil-ity and in the presence of other benthic organisms account for observed changes in the pro-cessing of phytodetritus in the different OMZ habitats. Foraminifera dominate the short-term processing of phytodetritus in the OMZ core but are less important in the lower OMZ bounda-ry region of the Indian margin as biological interactions and species distribution of foraminif-era change with depth and oxygen levels.

Nitrogen uptake into unfertilized pasture of the Willem Pretorius ...

African Journals Online (AJOL)

Nitrogen uptake into unfertilized pasture of the Willem Pretorius Game Reserve, ... The herbage yield of five main types of grassland in the Willem Pretorius Game Reserve was measured by clipping five 0, 5 m ... AJOL African Journals Online.

Nitrogen uptake and regeneration pathways in the equatorial Pacific: a basin scale modeling study

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R. Le Borgne

2009-11-01

Full Text Available It is well known that most primary production is fueled by regenerated nitrogen in the open ocean. Therefore, studying the nitrogen cycle by focusing on uptake and regeneration pathways would advance our understanding of nitrogen dynamics in the marine ecosystem. Here, we carry out a basin-scale modeling study, by assessing model simulations of nitrate and ammonium, and rates of nitrate uptake, ammonium uptake and regeneration in the equatorial Pacific. Model-data comparisons show that the model is able to reproduce many observed features of nitrate, ammonium, such as the deep ammonium maximum (DAM. The model also reproduces the observed de-coupling of ammonium uptake and regeneration, i.e., regeneration rate greater than uptake rate in the lower euphotic zone. The de-coupling largely explains the observed DAM in the equatorial Pacific Ocean. Our study indicates that zooplankton excretion and remineralization of organic nitrogen play a different role in nitrogen regeneration. Rates of zooplankton excretion vary from <0.01 mmol m⁻³ d⁻¹ to 0.1 mmol m⁻³ d⁻¹ in the upper euphotic zone while rates of remineralization fall within a narrow range (0.015–0.025 mmol m⁻³ d⁻¹ . Zooplankton excretion contributes up to 70% of total ammonium regeneration in the euphotic zone, and is largely responsible for the spatial variability of nitrogen regeneration. However, remineralization provides a steady supply of ammonium in the upper ocean, and is a major source of inorganic nitrogen for the oligotrophic regions. Overall, ammonium generation and removal are approximately balanced over the top 150 m in the equatorial Pacific.

Relationship of Nitrogen Use Efficiency with the Activities of Enzymes Involved in Nitrogen Uptake and Assimilation of Finger Millet Genotypes Grown under Different Nitrogen Inputs

Directory of Open Access Journals (Sweden)

Nidhi Gupta

2012-01-01

Full Text Available Nitrogen responsiveness of three-finger millet genotypes (differing in their seed coat colour PRM-1 (brown, PRM-701 (golden, and PRM-801 (white grown under different nitrogen doses was determined by analyzing the growth, yield parameters and activities of nitrate reductase (NR, glutamine synthetase (GS, glutamate synthase; GOGAT, and glutamate dehydrogenase (GDH at different developmental stages. High nitrogen use efficiency and nitrogen utilization efficiency were observed in PRM-1 genotype, whereas high nitrogen uptake efficiency was observed in PRM-801 genotype. At grain filling nitrogen uptake efficiency in PRM-1 negatively correlated with NR, GS, GOGAT activities whereas it was positively correlated in PRM-701 and PRM-801, however, GDH showed a negative correlation. Growth and yield parameters indicated that PRM-1 responds well at high nitrogen conditions while PRM-701 and PRM-801 respond well at normal and low nitrogen conditions respectively. The study indicates that PRM-1 is high nitrogen responsive and has high nitrogen use efficiency, whereas golden PRM-701 and white PRM-801 are low nitrogen responsive genotypes and have low nitrogen use efficiency. However, the crude grain protein content was higher in PRM-801 genotype followed by PRM-701 and PRM-1, indicating negative correlation of nitrogen use efficiency with source to sink relationship in terms of seed protein content.

Root distribution pattern and nitrogen uptake of some wheat and triticale germplasms in relation to rates and methods of nitrogen application

International Nuclear Information System (INIS)

Meena, N.L.; Seth, Jagdish

1975-01-01

A field experiment was conducted under irrigated conditions with four germplasms viz. Triticale(70-2), and wheat varieties HD 4502(durum), Kalyan Sona and Moti (aestivums) at the Indian Agricultural Research Institute Farm, New Delhi, during rabi season of 1972-73. The treatments comprised of three rates of nitrogen viz. 0,60 and 120 kg/ha and two methods of nitrogen application viz. (1) soil + foliar and (2) soil. The root distribution of the four germplasms, studied by 32 P injection technique was increased both vertically and horizontally with the addition of nitrogen. Root distribution of triticale was observed to be deep and spreading in habit, while durum proved to be shallow rooted and compact in nature. The total uptake of nitrogen was significantly increased with higher rates of nitrogen in all the germplasms. The maximum uptake of nitrogen was observed in the durum wheat. (author)

Understanding nitrate uptake, signaling and remobilisation for improving plant nitrogen use efficiency.

Science.gov (United States)

Kant, Surya

2018-02-01

The majority of terrestrial plants use nitrate as their main source of nitrogen. Nitrate also acts as an important signalling molecule in vital physiological processes required for optimum plant growth and development. Improving nitrate uptake and transport, through activation by nitrate sensing, signalling and regulatory processes, would enhance plant growth, resulting in improved crop yields. The increased remobilisation of nitrate, and assimilated nitrogenous compounds, from source to sink tissues further ensures higher yields and quality. An updated knowledge of various transporters, genes, activators, and microRNAs, involved in nitrate uptake, transport, remobilisation, and nitrate-mediated root growth, is presented. An enhanced understanding of these components will allow for their orchestrated fine tuning in efforts to improving nitrogen use efficiency in plants. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

[Effects of simulated nitrogen deposition on weeds growth and nitrogen uptake].

Science.gov (United States)

Jiang, Qiqing; Tang, Jianjun; Chen, Xin; Chen, Jing; Yang, Ruyi; Hu, S

2005-05-01

In this paper, a greenhouse experiment was conducted to study the responses of different functional groups weeds to simulated nitrogen deposition (4.0 g N.m(-2).yr(-1)). Native weed species Poa annua, Lolium perenne, Avena fatua, Medicago lupulina, Trifolium repens, Plantago virginica, Veronica didyma, Echinochloa crusgalli var. mitis, Eleusine indica and Amaranthus spinosus in orchard ecosystem were used test materials, and their above-and underground biomass and nitrogen uptake were measured. The results showed that under simulated N deposition, the total biomass, shoot biomass and root biomass of all weed species tended increase, while the total biomass was differed for different functional groups of weeds. The biomass of C4 grass, legumes and C3 grass was significantly increased under N deposition, while that of C3 and C4 forbs was not significantly impacted. The root/shoot biomass ratio of Avena fatua and Plantago virginica was enhanced by N deposition, but that of Poa annu, Lolium perenne, Medicago lupulina, Trifolium repens and Amarathus spinosus was not impacted significantly. N deposition had no significant effect on plant N concentration, but significantly enhanced the N uptake of all test weed species except Amarathus spinosus, Poa annua and Veronica didyma. was suggested that the further increase of N deposition might speed up the changes of the community structure weed species due to their different responses to N deposition.

Nitrogen uptake in the northeastern Arabian Sea during winter cooling

Digital Repository Service at National Institute of Oceanography (India)

Kumar, S.; Ramesh, R.; Dwivedi, R.M.; Raman, M.; Sheshshayee, M.S.; DeSouza, W.

/plain; charset=UTF-8 Hindawi Publishing Corporation International Journal of Oceanography Volume 2010, Article ID 819029, 11 pages doi:10.1155/2010/819029 Research Article Nitrogen Uptake in the Northeastern Arabian Sea during Winter Cooling S. Kumar, 1...

Contributing factors in foliar uptake of dissolved inorganic nitrogen at leaf level

Energy Technology Data Exchange (ETDEWEB)

Wuyts, Karen, E-mail: karen.wuyts@uantwerpen.be [Laboratory of Environmental and Urban Ecology, Research Group ENdEMIC, Dept. Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Forest and Nature Lab (ForNaLab), Dept. Forest and Water Management, Ghent University, Geraardsbergsesteenweg 267, B-9090 Gontrode-Melle (Belgium); Adriaenssens, Sandy, E-mail: adriaenssens@irceline.be [Belgian Interregional Environment Agency (IRCEL-CELINE), Kunstlaan 10–11, B-1210 Brussels (Belgium); Staelens, Jeroen, E-mail: jeroen_staelens@yahoo.com [Flemish Environment Agency (VMM), Kronenburgstraat 45, B-2000 Antwerp (Belgium); Wuytack, Tatiana, E-mail: tatiana.wuytack@uantwerpen.be [Laboratory of Environmental and Urban Ecology, Research Group ENdEMIC, Dept. Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Van Wittenberghe, Shari, E-mail: shari.vanwittenberghe@uantwerpen.be [Laboratory of Environmental and Urban Ecology, Research Group ENdEMIC, Dept. Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Boeckx, Pascal, E-mail: pascal.boeckx@ugent.be [Isotope Bioscience Laboratory (ISOFYS), Dept. Applied Analytical and Physical Chemistry, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium); Samson, Roeland, E-mail: roeland.samson@uantwerpen.be [Laboratory of Environmental and Urban Ecology, Research Group ENdEMIC, Dept. Bioscience Engineering, University of Antwerp, Groenenborgerlaan 171, B-2020 Antwerp (Belgium); Verheyen, Kris, E-mail: kris.verheyen@ugent.be [Forest and Nature Lab (ForNaLab), Dept. Forest and Water Management, Ghent University, Geraardsbergsesteenweg 267, B-9090 Gontrode-Melle (Belgium)

2015-02-01

We investigated the influence of leaf traits, rainwater chemistry, and pedospheric nitrogen (N) fertilisation on the aqueous uptake of inorganic N by physiologically active tree leaves. Leaves of juvenile silver birch and European beech trees, supplied with NH{sub 4}NO{sub 3} to the soil at rates from 0 to 200 kg N ha{sup −1} y{sup −1}, were individually exposed to 100 μl of artificial rainwater containing {sup 15}NH{sub 4}{sup +} or {sup 15}NO{sub 3}{sup −} at two concentration levels for one hour. In the next vegetative period, the experiment was repeated with NH{sub 4}{sup +} at the highest concentration only. The N form and the N concentration in the applied rainwater and, to a lesser extent, the pedospheric N treatment and the leaf traits affected the aqueous foliar N uptake. The foliar uptake of NH{sub 4}{sup +} by birch increased when leaves were more wettable. High leaf N concentration and leaf mass per area enhanced the foliar N uptake, and NO{sub 3}{sup −} uptake in particular, by birch. Variation in the foliar N uptake by the beech trees could not be explained by the leaf traits considered. In the first experiment, N fertilisation stimulated the foliar N uptake in both species, which was on average 1.42–1.78 times higher at the highest soil N dose than at the zero dose. However, data variability was high and the effect was not appreciable in the second experiment. Our data suggest that next to rainwater chemistry (N form and concentration) also forest N status could play a role in the partitioning of N entering the ecosystem through the soil and the canopy. Models of canopy uptake of aqueous N at the leaf level should take account of leaf traits such as wettability and N concentration. - Highlights: • Foliar uptake of dissolved inorganic nitrogen (N) by potted trees was studied. • Leaves were individually exposed to rainwater drops containing {sup 15}NH{sub 4}{sup +} or {sup 15}NO{sub 3}{sup −}. • Foliar N uptake efficiency depended on

Regulation of nitrogen uptake and assimilation: Effects of nitrogen source and root-zone and aerial environment on growth and productivity of soybean

Science.gov (United States)

Raper, C. David, Jr.

1994-01-01

The interdependence of root and shoot growth produces a functional equilibrium as described in quantitative terms by numerous authors. It was noted that bean seedlings grown in a constant environment tended to have a constant distribution pattern of dry matter between roots and leaves characteristic of the set of environmental conditions. Disturbing equilibrium resulted in a change in relative growth of roots and leaves until the original ratio was restored. To define a physiological basis for regulation of nitrogen uptake within the balance between root and shoot activities, the authors combined a partioning scheme and a utilization priority assumption in which: (1) all carbon enters the plant through photosynthesis in leaves and all nitrogen enters the plant through active uptake by roots, (2) nitrogen uptake by roots and secretion into the xylem for transport to the shoots are active processes, (3) availability of exogenous nitrogen determines concentration of soluble carbohydrates within the roots, (4) leaves are a source and a sink for carbohydrates, and (5) the requirement for nitrogen by leaf growth is proportionally greater during initiation and early expansion than during later expansion.

Simulating Root Density Dynamics and Nitrogen Uptake – Can a Simple Approach be Sufficient?

OpenAIRE

Pedersen, Anders; Zhang, Kefeng; Jensen, Lars Stoumann; Thorup-Kristensen, Kristian

2007-01-01

The modeling of root growth in many plant–soil models is simple and with few possibilities to adapt simulated root proliferation and depth distribution to that actually found with different crop species. Here we propose a root model, developed to describe root growth, root density and nitrogen uptake. The model focuses on annual crops, and attempts to model root growth of different crop species and row crops and its significance for nitrogen uptake from different parts of the soil volume.

Linking phytoplankton nitrogen uptake, macronutrients and chlorophyll- a in SW Atlantic waters: The case of the Gulf of San Jorge, Argentina

Science.gov (United States)

Paparazzo, Flavio E.; Williams, Gabriela N.; Pisoni, Juan P.; Solís, Miriam; Esteves, José L.; Varela, Diana E.

2017-08-01

We compared biological and chemical parameters in surface waters of the Gulf of San Jorge to better understand carbon export and the factors that control phytoplankton production in an area of the Argentinian Continental Shelf, a vastly under sampled region of the SW Atlantic Ocean. In April of 2012, we estimated new and regenerated primary production in the Gulf by measuring nitrate and ammonium uptake, respectively. We also measured macronutrient, and in situ chlorophyll-a concentrations, which were compared to chlorophyll-a estimates from remote sensing. Although the Gulf of San Jorge presents high levels of chlorophyll-a and primary production, the relationship between these parameters is not straightforward. Previous studies showed that surface chlorophyll-a explains only part of the variance in euphotic-zone integrated primary production, and that satellite-derived chlorophyll-a underestimates in situ primary production. Our results showed large spatial variability in the Gulf, with transitional physico-chemical conditions, such as fronts, that could favor an increase in biological production. In situ chlorophyll-a concentrations were highest at the mid-shelf station (6.0 mg m- 3) and lowest at the northernmost location by an order of magnitude. Remote sensing measurements of chlorophyll-a underestimated our in situ chlorophyll-a concentrations. Total nitrogen (nitrate + ammonium) uptake showed relatively similar rates throughout the study area (≈ 130 nM-N d- 1), except in the northernmost station where it was much lower (53 nM-N d- 1). This north region had a distinct water mass and maximal levels of macronutrients (nitrate ≈ 6 μM, ammonium ≈ 1.2 μM, phosphate ≈ 1.2 μM and silicic acid ≈ 4 μM). For the entire sampling region, chlorophyll-a concentrations strongly correlated with total nitrogen uptake (r = 0.76, n = 8, p < 0.05) and new primary production (r = 0.78, n = 8, p < 0.05). Values of the f-ratio were 0.9 in mid-shelf, and ranged

Nitrogen uptake efficiency of irrigated wheat in Egypt

International Nuclear Information System (INIS)

Abdel Monem, M.A.S.

2000-01-01

Egypt's current wheat production would be impossible without N fertilizers, the consumption of which has increased more than 75% in the last 20 years. The efficiency of uptake of applied N is low, and better management of both fertilizer and irrigation is needed to improve N recovery by crops and reduce losses from the plant/soil system. Field trials were conducted over a 3-year period, on Egypt's three main soil types: old irrigated land of the Nile valley, newly reclaimed sandy and calcareous soils, and salt-affected soil of the north delta. The responses of wheat cultivars to N, and patterns of N uptake and N loss, as affected by irrigation regime, were examined using 15 N. Cultivar Sakha 69 was more responsive to applied N and assimilated N more efficiently than other varieties under different soil types. Nitrogen loss from the sandy soil was as high as 57% whereas average loss in the clay soil was 17%. A higher water table in the salt-affected soil negatively affected N uptake. Irrigation with 75% of the required water for wheat had no effect on yield or N-uptake. (author)

Influence of the form and rate of 15N-labelled nitrogen fertilizers on nitrogen uptake by maize grown on two different soils

International Nuclear Information System (INIS)

Balabanova-Georgieva, R.; Ikonomova, E.

1996-01-01

The influence of 15 N-labelled urea and ammonium sulfate on the yield and uptake of fertilizer nitrogen and soil nitrogen by maize was studied under the conditions of pot experiments on calcareous black earth and leached black earth. The nitrogen fertilizers were applied in rates: N 1 =250 mg, N 2 =500 mg, N 3 =750 mg and N 4 =1000 mg/1 kg of soil, on phosphorus(P)-potassium(K) background (P=200 and K=600 mg/kg soil). When treating with N 3 and N 4 , the application of the whole nitrogen rate was compared with its split application. It was found that the form of the nitrogen fertilizer played no important role for the formation of the yield of biomass and the uptake of nitrogen with the yield when it is applied in low nitrogen rates and maize was grown on calcareous black earth. The yield of biomass and the uptake of nitrogen with the yield of maize reach their maximum under the conditions of calcareous black earth and high nitrogen rates applied as urea depressed the plants which proves the statement that in case of calcareous black earth application of ammonium sulfate should be preferred rather that urea, fertilization with which should be avoided. No depression of plants was observed under the conditions of leached black earth and application of high urea rates. The amount of nitrogen taken up is growing with the increasing of the nitrogen rate (excluding the N-treatment). The split application of high nitrogen rates increased notably the yield of maize-vegetation mass which proved the great ability of this crop for effective utilization of the nitrogen fertilizers when applied in portions and at suitable phases of plant vegetation. The role of the fertilizer nitrogen on the formation of the plant mass yield is much greater compared to that of the soil nitrogen; in the split application of urea the soil nitrogen plays a much bigger role than in its single application. The additional mobilization of the soil nitrogen under the influence of the applied nitrogen

Nocturnal uptake and assimilation of nitrogen dioxide by C3 and CAM plants.

Science.gov (United States)

Takahashi, Misa; Konaka, Daisuke; Sakamoto, Atsushi; Morikawa, Hiromichi

2005-01-01

In order to investigate nocturnal uptake and assimilation of NO2 by C3 and crassulacean acid metabolism (CAM) plants, they were fumigated with 4 microl l(-1) 15N-labeled nitrogen dioxide (NO2) for 8 h. The amount of NO2 and assimilation of NO2 by plants were determined by mass spectrometry and Kjeldahl-nitrogen based mass spectrometry, respectively. C3 plants such as kenaf (Hibiscus cannabinus), tobacco (Nicotiana tabacum) and ground cherry (Physalis alkekengi) showed a high uptake and assimilation during daytime as high as 1100 to 2700 ng N mg(-1) dry weight. While tobacco and ground cherry strongly reduced uptake and assimilation of NO2 during nighttime, kenaf kept high nocturnal uptake and assimilation of NO2 as high as about 1500 ng N mg(-1) dry weight. Stomatal conductance measurements indicated that there were no significant differences to account for the differences in the uptake of NO2 by tobacco and kenaf during nighttime. CAM plants such as Sedum sp., Kalanchoe blossfeldiana (kalanchoe) and Aloe arborescens exhibited nocturnal uptake and assimilation of NO2. However, the values of uptake and assimilation of NO2 both during daytime and nighttime was very low (at most about 500 ng N mg(-1) dry weight) as compared with those of above mentioned C3 plants. The present findings indicate that kenaf is an efficient phytoremediator of NO2 both during daytime and nighttime.

Can Canopy Uptake Influence Nitrogen Acquisition and Allocation by Trees?

Science.gov (United States)

Nair, Richard; Perks, Mike; Mencuccini, Maurizio

2015-04-01

Nitrogen (N) fertilization due to atmospheric deposition of anthropogenic nitrogen (NDEP) may explain some of the net carbon (C) sink (0.6-0.7 Pg y-1) in temperate forests, but estimates of the additional C uptake due to atmospheric N additions (ΔCΔN) can vary by over an order of magnitude (~ 5 to 200 ΔCΔN). High estimates from several recent studies [e.g. Magnani (2007), Nature 447 848-850], deriving ΔCΔN from regional correlations between NDEP and measures of C uptake (such as eddy covariance -derived net ecosystem production, or forest inventory data) contradict estimates from other studies of 15N tracer applications added as fertilizer to the forest floor. A strong ΔCΔN effect requires nitrogen to be efficiently acquired by trees and allocated to high C:N, long-lived woody tissues, but these isotope experiments typically report relatively little (~ 20 %) of 15N added is found above-ground, with estimates are often attributed to co-variation with other factors across the range of sites investigated. However 15N-fertilization treatments often impose considerably higher total N loads than ambient NDEP and almost exclusively only apply mineral 15N treatments to the soil, often in a limited number of treatment events over relatively short periods of time. Excessive N deposition loads can induce negative physiological effects and limit the resulting ΔCΔN observed, and applying treatments to the soil may ignore the importance of canopy nitrogen uptake in overall forest nutrition. As canopies can directly take up nitrogen, the chronic, (relatively) low levels of ambient NDEP inputs from pollution may be acquired without some of the effects of heavy N loads, obtaining this N before it reaches the soil, and allowing canopies to substitute for, or supplement, edaphic N nutrition. The strength of this effect depends on how much N uptake can occur across the canopy under field conditions, and if this extra N supplies growth in woody tissues such as the stem, as

Nitrogen uptake dynamics, yield and quality as influenced by nitrogen fertilization in Piel de sapo melon

Energy Technology Data Exchange (ETDEWEB)

Castellanos, M. T.; Cabello, M. J.; Cartagena, M. C.; Tarquis, A. M.; Arce, A.; Ribas, F.

2012-11-01

The need to reduce nitrogen (N) fertilizer pollution strengthens the importance of improving the utilization efficiency of applied N to crops. This requires knowledge of crop N uptake characteristics and how fertilization management affects it. A three-year field experiment was conducted from May to September in central Spain to investigate the influence of different N rates, which ranged from 11 to 393 kg ha{sup -}1, applied through drip irrigation, on the dynamics of N uptake, nitrogen use efficiency (NUE), fruit yield and quality of a Piel de sapo melon crop (Cucumis melo L. cv. Sancho). Both N concentration and N content increased in different plant parts with the N rate. Leaves had the highest N concentration, which declined by 40-50% from 34-41 days after transplanting (DAT), while the highest N uptake rate was observed from 30-35 to 70-80 DAT, coinciding with fruit development. In each year, NUE declined with increasing N rate. With N fertilizer applications close to the optimum N rate of 90-100 kg ha -1, the fruits removed approximately 60 kg N ha -1, and the amount of N in the crop residue was about 80 kg N ha -1; this serves to replenish the organic nutrient pool in the soil and may be used by subsequent crops following mineralization. (Author) 36 refs.

Uptake of exogenous spermidine by rat lungs perfused in situ

International Nuclear Information System (INIS)

Rannels, D.E.; Addison, J.L.

1987-01-01

Uptake of the polyamine spermidine (SPD) from the pulmonary circulation was characterized by using ventilated rat lungs perfused in situ with Krebs-Henseleit-bicarbonate buffer containing 4.5% bovine serum albumin, 5.6 mM glucose, and 20 amino acids at plasma levels. [ 14 C]SPD was accumulated by the lungs in a time- and concentration-dependent manner. The pathway of SPD uptake exhibited saturation kinetics with an apparent K/sub m/ in the range of 1 μM and a V/sub max/ of 450-540 pmol/g lung min. SPD uptake was inhibited by the naturally occurring polyamines putrescine and spermine (SPM) and by the inhibitor of polyamine synthesis, methyglyoxal bis(guanylhydrazone) (MGBG). Inhibition of SPD uptake by SPM followed competitive kinetics; although MGBG was also a competitive inhibitor of SPD uptake, MGBG was less effective than SPM. These observations indicate that SPD is taken up from the pulmonary circulation by a carrier-mediated pathway that is inhibited by other natural polyamines and by MGBG and exhibits by other natural polyamines and by MGBG and exhibits substrate affinity in the range of plasma SPD concentrations

Uptake of exogenous spermidine by rat lungs perfused in situ

Energy Technology Data Exchange (ETDEWEB)

Rannels, D.E.; Addison, J.L.

1987-01-01

Uptake of the polyamine spermidine (SPD) from the pulmonary circulation was characterized by using ventilated rat lungs perfused in situ with Krebs-Henseleit-bicarbonate buffer containing 4.5% bovine serum albumin, 5.6 mM glucose, and 20 amino acids at plasma levels. (/sup 14/C)SPD was accumulated by the lungs in a time- and concentration-dependent manner. The pathway of SPD uptake exhibited saturation kinetics with an apparent K/sub m/ in the range of 1 ..mu..M and a V/sub max/ of 450-540 pmol/g lung min. SPD uptake was inhibited by the naturally occurring polyamines putrescine and spermine (SPM) and by the inhibitor of polyamine synthesis, methyglyoxal bis(guanylhydrazone) (MGBG). Inhibition of SPD uptake by SPM followed competitive kinetics; although MGBG was also a competitive inhibitor of SPD uptake, MGBG was less effective than SPM. These observations indicate that SPD is taken up from the pulmonary circulation by a carrier-mediated pathway that is inhibited by other natural polyamines and by MGBG and exhibits by other natural polyamines and by MGBG and exhibits substrate affinity in the range of plasma SPD concentrations.

Effects of inorganic nitrogen forms on growth, morphology, nitrogen uptake capacity and nutrient allocation of four tropical aquatic macrophytes (Salvinia cucullata, Ipomoea aquatica, Cyperus involucratus and Vetiveria zizanioides)

DEFF Research Database (Denmark)

Jampeetong, Arunothai; Brix, Hans; Kantawanichkul, Suwasa

2012-01-01

This study assesses the growth and morphological responses, nitrogen uptake and nutrient allocation in four aquatic macrophytes when supplied with different inorganic nitrogen treatments (1) NH4+, (2) NO3−, or (3) both NH4+ and NO3−. Two free-floating species (Salvinia cucullata Roxb. ex Bory...... and Ipomoea aquatica Forssk.) and two emergent species (Cyperus involucratus Rottb. and Vetiveria zizanioides (L.) Nash ex Small) were grown with these N treatments at equimolar concentrations (500 M). Overall, the plants responded well to NH4+. Growth as RGR was highest in S. cucullata (0.12±0.003 d−1......) followed by I. aquatica (0.035 ±0.002 d−1), C. involucratus (0.03±0.002 d−1) and V. zizanioides (0.02±0.003 d−1). The NH4+ uptake rate was significantly higher than the NO3− uptake rate. The free-floating species had higher nitrogen uptake rates than the emergent species. The N-uptake rate differed between...

Nitrogen removal in maturation waste stabilisation ponds via biological uptake and sedimentation of dead biomass.

Science.gov (United States)

Camargo Valero, M A; Mara, D D; Newton, R J

2010-01-01

In this work a set of experiments was undertaken in a pilot-scale WSP system to determine the importance of organic nitrogen sedimentation on ammonium and total nitrogen removals in maturation ponds and its seasonal variation under British weather conditions, from September 2004 to May 2007. The nitrogen content in collected sediment samples varied from 4.17% to 6.78% (dry weight) and calculated nitrogen sedimentation rates ranged from 273 to 2868 g N/ha d. High ammonium removals were observed together with high concentrations of chlorophyll-a in the pond effluent. Moreover, chlorophyll-a had a very good correlation with the corresponding increment of VSS (algal biomass) and suspended organic nitrogen (biological nitrogen uptake) in the maturation pond effluents. Therefore, when ammonium removal reached its maximum, total nitrogen removal was very poor as most of the ammonia taken up by algae was washed out in the pond effluent in the form of suspended solids. After sedimentation of the dead algal biomass, it was clear that algal-cell nitrogen was recycled from the sludge layer into the pond water column. Recycled nitrogen can either be taken up by algae or washed out in the pond effluent. Biological (mainly algal) uptake of inorganic nitrogen species and further sedimentation of dead biomass (together with its subsequent mineralization) is one of the major mechanisms controlling in-pond nitrogen recycling in maturation WSP, particularly when environmental and operational conditions are favourable for algal growth.

Effects of urban stream burial on nitrogen uptake and ...

Science.gov (United States)

Urbanization has resulted in extensive burial and channelization of headwater streams, yet little is known about impacts on stream ecosystem functions critical for reducing downstream nitrogen pollution. To characterize the biogeochemical impact of stream burial, we measured NO3- uptake, using 15N-NO3- isotope tracer releases, and whole stream metabolism, during four seasons in three paired buried and open streams reaches within the Baltimore Ecosystem Study Long-term Ecological Research Network. Stream burial increased NO3- uptake lengths, by a factor of 7.5 (p < 0.01) and decreased nitrate uptake velocity and areal nitrate uptake rate by factors of 8.2 (p = 0.01) and 9.6 (p < 0.001), respectively. Stream burial decreased gross primary productivity by a factor of 9.2 (p < 0.05) and decreased ecosystem respiration by a factor of 4.2 (p = 0.06). From statistical analysis of Excitation Emissions Matrices (EEMs), buried streams were also found to have significantly less labile dissolved organic matter. Furthermore, buried streams had significantly lower transient storage and water temperatures. Overall, differences in NO3- uptake and metabolism were primarily explained by decreased transient storage and light availability in buried streams. We estimate that stream burial increases daily watershed nitrate export by as much as 500% due to decreased in-stream retention and may considerably decrease carbon export via decreased primary production. These results

New nitrogen uptake strategy: specialized snow roots.

Science.gov (United States)

Onipchenko, Vladimir G; Makarov, Mikhail I; van Logtestijn, Richard S P; Ivanov, Viktor B; Akhmetzhanova, Assem A; Tekeev, Dzhamal K; Ermak, Anton A; Salpagarova, Fatima S; Kozhevnikova, Anna D; Cornelissen, Johannes H C

2009-08-01

The evolution of plants has yielded a wealth of adaptations for the acquisition of key mineral nutrients. These include the structure, physiology and positioning of root systems. We report the discovery of specialized snow roots as a plant strategy to cope with the very short season for nutrient uptake and growth in alpine snow-beds, i.e. patches in the landscape that remain snow-covered well into the summer. We provide anatomical, chemical and experimental (15)N isotope tracking evidence that the Caucasian snow-bed plant Corydalis conorhiza forms extensive networks of specialized above-ground roots, which grow against gravity to acquire nitrogen directly from within snow packs. Snow roots capture nitrogen that would otherwise partly run off down-slope over a frozen surface, thereby helping to nourish these alpine ecosystems. Climate warming is changing and will change mountain snow regimes, while large-scale anthropogenic N deposition has increased snow N contents. These global changes are likely to impact on the distribution, abundance and functional significance of snow roots.

Effect of partial root zone drying and deficit irrigation on nitrogen and phosphorus uptake in potato

DEFF Research Database (Denmark)

Liu, Caixia; Rubæk, Gitte Holton; Liu, Fulai

2015-01-01

Better understanding of the effects of deficit irrigation regimes on phosphorus (P) and nitrogen (N) uptake dynamics is necessary for sustainable water, P and N management. The effects of full (FI), deficit (DI) and partial root-zone drying (PRD) irrigation on potato P and N uptake with P fertili...... was superior to DI in terms of N uptake, but not P uptake. Challenges remain how to maintain crop yield and P uptake under reduced irrigation regimes. Utilization of water and N fertilizer was low when the soil was deficient in P.......Better understanding of the effects of deficit irrigation regimes on phosphorus (P) and nitrogen (N) uptake dynamics is necessary for sustainable water, P and N management. The effects of full (FI), deficit (DI) and partial root-zone drying (PRD) irrigation on potato P and N uptake with P...... fertilization (P1) or without (P0) were investigated in two split-root pot experiments in a soil with low plant available P. Under FI, the plants were irrigated to pot water holding capacity while under DI and PRD, 70% of the water amount of FI was applied on either both or one side of the pots, respectively...

Studies on nitrogen uptake and utilization by rape (Brassica napus L.) under different sowing dates

International Nuclear Information System (INIS)

Liu Qixin; Nie Guangming

1992-01-01

The nitrogen uptake and utilization by low erucic acid variety, Zhong You Di Gai No.2, of rape (Brassica napus L.) under different sowing dates were studied. Total N uptake, the percentage N derived from the fertilizer, the rate of utilization of nitrogenous fertilizer, the production efficiency of N-fertilizer (seed yield g/gN derived by rape plant from the fertilizer), total P uptake and the production efficiency of phosphorus (seed yield g/gP derived by rape plant from fertilizer and soil) were all significantly higher at early sowing than that at later sowing within the range of normal sowing dates. Therefore, the biomass yield, the seed yield and oil content all increased significantly at early sowing treatment, but erucic acid content showed no significant difference

Molecular fundamentals of nitrogen uptake and transport in trees.

Science.gov (United States)

Castro-Rodríguez, Vanessa; Cañas, Rafael A; de la Torre, Fernando N; Pascual, Ma Belén; Avila, Concepción; Cánovas, Francisco M

2017-05-01

Nitrogen (N) is frequently a limiting factor for tree growth and development. Because N availability is extremely low in forest soils, trees have evolved mechanisms to acquire and transport this essential nutrient along with biotic interactions to guarantee its strict economy. Here we review recent advances in the molecular basis of tree N nutrition. The molecular characteristics, regulation, and biological significance of membrane proteins involved in the uptake and transport of N are addressed. The regulation of N uptake and transport in mycorrhized roots and transcriptome-wide studies of N nutrition are also outlined. Finally, several areas of future research are suggested. © The Author 2017. Published by Oxford University Press on behalf of the Society for Experimental Biology. All rights reserved. For permissions, please email: journals.permissions@oup.com.

Carbon availability for the fungus triggers nitrogen uptake and transport in the arbuscular mycorrhizal symbiosis

Science.gov (United States)

The arbuscular mycorrhizal (AM) symbiosis is characterized by a transfer of nutrients in exchange for carbon. We tested the effect of the carbon availability for the AM fungus Glomus intraradices on nitrogen (N) uptake and transport in the symbiosis. We followed the uptake and transport of 15N and ...

Elevated CO2 plus chronic warming reduce nitrogen uptake and levels or activities of nitrogen-uptake and -assimilatory proteins in tomato roots.

Science.gov (United States)

Jayawardena, Dileepa M; Heckathorn, Scott A; Bista, Deepesh R; Mishra, Sasmita; Boldt, Jennifer K; Krause, Charles R

2017-03-01

Atmospheric CO 2 enrichment is expected to often benefit plant growth, despite causing global warming and nitrogen (N) dilution in plants. Most plants primarily procure N as inorganic nitrate (NO 3 - ) or ammonium (NH 4 + ), using membrane-localized transport proteins in roots, which are key targets for improving N use. Although interactive effects of elevated CO 2 , chronic warming and N form on N relations are expected, these have not been studied. In this study, tomato (Solanum lycopersicum) plants were grown at two levels of CO 2 (400 or 700 ppm) and two temperature regimes (30 or 37°C), with NO 3 - or NH 4 + as the N source. Elevated CO 2 plus chronic warming severely inhibited plant growth, regardless of N form, while individually they had smaller effects on growth. Although %N in roots was similar among all treatments, elevated CO 2 plus warming decreased (1) N-uptake rate by roots, (2) total protein concentration in roots, indicating an inhibition of N assimilation and (3) shoot %N, indicating a potential inhibition of N translocation from roots to shoots. Under elevated CO 2 plus warming, reduced NO 3 - -uptake rate per g root was correlated with a decrease in the concentration of NO 3 - -uptake proteins per g root, reduced NH 4 + uptake was correlated with decreased activity of NH 4 + -uptake proteins and reduced N assimilation was correlated with decreased concentration of N-assimilatory proteins. These results indicate that elevated CO 2 and chronic warming can act synergistically to decrease plant N uptake and assimilation; hence, future global warming may decrease both plant growth and food quality (%N). © 2016 Scandinavian Plant Physiology Society.

Host-derived viral transporter protein for nitrogen uptake in infected marine phytoplankton

Science.gov (United States)

Chambouvet, Aurélie; Milner, David S.; Attah, Victoria; Terrado, Ramón; Lovejoy, Connie; Moreau, Hervé; Derelle, Évelyne; Richards, Thomas A.

2017-01-01

Phytoplankton community structure is shaped by both bottom–up factors, such as nutrient availability, and top–down processes, such as predation. Here we show that marine viruses can blur these distinctions, being able to amend how host cells acquire nutrients from their environment while also predating and lysing their algal hosts. Viral genomes often encode genes derived from their host. These genes may allow the virus to manipulate host metabolism to improve viral fitness. We identify in the genome of a phytoplankton virus, which infects the small green alga Ostreococcus tauri, a host-derived ammonium transporter. This gene is transcribed during infection and when expressed in yeast mutants the viral protein is located to the plasma membrane and rescues growth when cultured with ammonium as the sole nitrogen source. We also show that viral infection alters the nature of nitrogen compound uptake of host cells, by both increasing substrate affinity and allowing the host to access diverse nitrogen sources. This is important because the availability of nitrogen often limits phytoplankton growth. Collectively, these data show that a virus can acquire genes encoding nutrient transporters from a host genome and that expression of the viral gene can alter the nutrient uptake behavior of host cells. These results have implications for understanding how viruses manipulate the physiology and ecology of phytoplankton, influence marine nutrient cycles, and act as vectors for horizontal gene transfer. PMID:28827361

Variation in summer nitrogen and phosphorus uptake among Siberian headwater streams

Directory of Open Access Journals (Sweden)

John D. Schade

2016-06-01

Full Text Available Arctic streams are likely to receive increased inputs of dissolved nutrients and organic matter from thawing permafrost as climate warms. Documenting how Arctic streams process inorganic nutrients is necessary to understand mechanisms that regulate watershed fluxes of permafrost-derived materials to downstream ecosystems. We report on summer nitrogen (N and phosphorus (P uptake in streams draining upland soils from the Pleistocene, and lowland floodplain soils from the Holocene, in Siberia's Kolyma River watershed. Uptake of N and P differed between upland and floodplain streams, suggesting topographic variation in nutrient limitation. In floodplain streams, P uptake rate and uptake velocity were higher than N, while upland streams had similar values for all N and P uptake metrics. Phosphorus uptake velocity and size of the transient hydrologic storage zone were negatively related across all study streams, indicating strong influence of hydrologic processes on nutrient fluxes. Physical sorption of P was higher in floodplain stream sediments relative to upland stream sediments, suggesting more physically driven uptake in floodplain streams and higher biological activity in upland streams. Overall, these results demonstrate that high-latitude headwater streams actively retain N and P during summer base flows; however, floodplain and upland streams varied substantially in N and P uptake and may respond differently to inorganic nutrient and organic matter inputs. Our results highlight the need for a comprehensive assessment of N and P uptake and retention in Arctic streams in order to fully understand the impact of permafrost-derived materials on ecosystem processes, and their fate in continental drainage networks.

Land use/land cover and scale influences on in-stream nitrogen uptake kinetics

Science.gov (United States)

Covino, Tim; McGlynn, Brian; McNamara, Rebecca

2012-06-01

Land use/land cover change often leads to increased nutrient loading to streams; however, its influence on stream ecosystem nutrient transport remains poorly understood. Given the deleterious impacts elevated nutrient loading can have on aquatic ecosystems, it is imperative to improve understanding of nutrient retention capacities across stream scales and watershed development gradients. We performed 17 nutrient addition experiments on six streams across the West Fork Gallatin Watershed, Montana, USA, to quantify nitrogen uptake kinetics and retention dynamics across stream sizes (first to fourth order) and along a watershed development gradient. We observed that stream nitrogen (N) uptake kinetics and spiraling parameters varied across streams of different development intensity and scale. In more developed watersheds we observed a fertilization affect. This fertilization affect was evident as increased ash-free dry mass, chlorophylla, and ambient and maximum uptake rates in developed as compared to undeveloped streams. Ash-free dry mass, chlorophylla, and the number of structures in a subwatershed were significantly correlated to nutrient spiraling and kinetic parameters, while ambient and average annual N concentrations were not. Additionally, increased maximum uptake capacities in developed streams contributed to low in-stream nutrient concentrations during the growing season, and helped maintain watershed export at low levels during base flow. Our results indicate that land use/land cover change can enhance in-stream uptake of limiting nutrients and highlight the need for improved understanding of the watershed dynamics that control nutrient export across scales and development intensities for mitigation and protection of aquatic ecosystems.

Use of bioreactor landfill for nitrogen removal to enhance methane production through ex situ simultaneous nitrification-denitrification and in situ denitrification.

Science.gov (United States)

Sun, Xiaojie; Zhang, Hongxia; Cheng, Zhaowen

2017-08-01

High concentrations of nitrate-nitrogen (NO 3 - -N) derived from ex situ nitrification phase can inhibit methane production during ex situ nitrification and in situ denitrification bioreactor landfill. A combined process comprised of ex situ simultaneous nitrification-denitrification (SND) in an aged refuse bioreactor (ARB) and in situ denitrification in a fresh refuse bioreactor (FRB) was conducted to reduce the negative effect of high concentrationsof NO 3 - -N. Ex situ SND can be achieved because NO 3 - -N concentration can be reduced and the removal rate of ammonium-nitrogen (NH 4 + -N) remains largely unchanged when the ventilation rate of ARB-A2 is controlled. The average NO 3 - -N concentrations of effluent were 470mg/L in ex situ nitrification ARB-A1 and 186mg/L in ex situ SND ARB-A2. The average NH 4 + -N removal rates of ARB-A1 and ARB-A2 were 98% and 94%, respectively. Based on the experimental data from week 4 to week 30, it is predicted that NH 4 + -N concentration in FRB-F1 of the ex situ nitrification and in situ denitrification process would reach 25mg/L after 63weeks, and about 40weeks for the FRB-F2 of ex situ SND and in situ denitrification process . Ex situ SND and in situ denitrification process can improve themethane production of FRB-F2. The lag phase time of methane production for the FRB-F2 was 11weeks. This phase was significantly shorter than the 15-week phases of FRB-F1 in ex situ nitrification and in situ denitrification process. A seven-week stabilizationphase was required to increase methane content from 5% to 50% for FRB-F2. Methane content in FRB-F1 did not reach 50% but reached the 45% peak after 20weeks. Copyright © 2017 Elsevier Ltd. All rights reserved.

Nitrogen deposition and prey nitrogen uptake control the nutrition of the carnivorous plant Drosera rotundifolia

Energy Technology Data Exchange (ETDEWEB)

Millett, J., E-mail: j.millett@lboro.ac.uk [Centre for Hydrological and Ecosystem Science, Department of Geography, Loughborough University, Loughborough LE11 3TU (United Kingdom); Foot, G.W. [Centre for Hydrological and Ecosystem Science, Department of Geography, Loughborough University, Loughborough LE11 3TU (United Kingdom); Svensson, B.M. [Department of Plant Ecology and Evolution, Uppsala University, Norbyvägen 18 D, SE-752 36 Uppsala (Sweden)

2015-04-15

Nitrogen (N) deposition has important negative impacts on natural and semi-natural ecosystems, impacting on biotic interactions across trophic levels. Low-nutrient systems are particularly sensitive to changes in N inputs and are therefore more vulnerable to N deposition. Carnivorous plants are often part of these ecosystems partly because of the additional nutrients obtained from prey. We studied the impact of N deposition on the nutrition of the carnivorous plant Drosera rotundifolia growing on 16 ombrotrophic bogs across Europe. We measured tissue N, phosphorus (P) and potassium (K) concentrations and prey and root N uptake using a natural abundance stable isotope approach. Our aim was to test the impact of N deposition on D. rotundifolia prey and root N uptake, and nutrient stoichiometry. D. rotundifolia root N uptake was strongly affected by N deposition, possibly resulting in reduced N limitation. The contribution of prey N to the N contained in D. rotundifolia ranged from 20 to 60%. N deposition reduced the maximum amount of N derived from prey, but this varied below this maximum. D. rotundifolia tissue N concentrations were a product of both root N availability and prey N uptake. Increased prey N uptake was correlated with increased tissue P concentrations indicating uptake of P from prey. N deposition therefore reduced the strength of a carnivorous plant–prey interaction, resulting in a reduction in nutrient transfer between trophic levels. We suggest that N deposition has a negative impact on D. rotundifolia and that responses to N deposition might be strongly site specific. - Highlights: • We measured nutrition of the carnivorous plant Drosera rotundifolia across Europe. • We measured tissue nutrient concentrations and prey and root N uptake at 16 sites. • Tissue N concentrations were a product of root N availability and prey N uptake. • N deposition reduced the maximum amount of N derived from prey. • N deposition reduced the strength of a

Nitrogen deposition and prey nitrogen uptake control the nutrition of the carnivorous plant Drosera rotundifolia

International Nuclear Information System (INIS)

Millett, J.; Foot, G.W.; Svensson, B.M.

2015-01-01

Nitrogen (N) deposition has important negative impacts on natural and semi-natural ecosystems, impacting on biotic interactions across trophic levels. Low-nutrient systems are particularly sensitive to changes in N inputs and are therefore more vulnerable to N deposition. Carnivorous plants are often part of these ecosystems partly because of the additional nutrients obtained from prey. We studied the impact of N deposition on the nutrition of the carnivorous plant Drosera rotundifolia growing on 16 ombrotrophic bogs across Europe. We measured tissue N, phosphorus (P) and potassium (K) concentrations and prey and root N uptake using a natural abundance stable isotope approach. Our aim was to test the impact of N deposition on D. rotundifolia prey and root N uptake, and nutrient stoichiometry. D. rotundifolia root N uptake was strongly affected by N deposition, possibly resulting in reduced N limitation. The contribution of prey N to the N contained in D. rotundifolia ranged from 20 to 60%. N deposition reduced the maximum amount of N derived from prey, but this varied below this maximum. D. rotundifolia tissue N concentrations were a product of both root N availability and prey N uptake. Increased prey N uptake was correlated with increased tissue P concentrations indicating uptake of P from prey. N deposition therefore reduced the strength of a carnivorous plant–prey interaction, resulting in a reduction in nutrient transfer between trophic levels. We suggest that N deposition has a negative impact on D. rotundifolia and that responses to N deposition might be strongly site specific. - Highlights: • We measured nutrition of the carnivorous plant Drosera rotundifolia across Europe. • We measured tissue nutrient concentrations and prey and root N uptake at 16 sites. • Tissue N concentrations were a product of root N availability and prey N uptake. • N deposition reduced the maximum amount of N derived from prey. • N deposition reduced the strength of a

Relationships between streamwater nitrogen and primary uptake compartments: an isotopic approach

OpenAIRE

Pastor Oliveras, Ada

2014-01-01

The overarching goal of this dissertation was to explore relationships between streamwater nitrogen (N) and the most representative primary uptake compartments (PUCs) in stream ecosystems (e.g. microbial biofilm, algae, bryophytes, macrophytes). In particular, environmental factors driving these biogeochemical relationships along a strong anthropogenic gradient were explored and differences among and within PUC types were compared. To elucidate the factors controlling these relationships, we ...

Nitrogen uptake and rate-limiting step in low-temperature nitriding of iron

NARCIS (Netherlands)

Inia, DK; Vredenberg, AM; Habraken, FHPM; Boerma, DO

1999-01-01

Recently, a method to nitride iron in NH3 ambients at low temperature (225-350 degrees C) has been developed. In this method, the Fe is covered with a thin (similar to 40 nm) Ni layer, which acts as a catalyst for the nitriding process. From experiments, in which the amount of nitrogen uptake is

Nitrogen isotope fractionation during N uptake via arbuscular mycorrhizal and ectomycorrhizal fungi into grey alder.

Science.gov (United States)

Schweiger, Peter F

2016-10-20

Arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) fungi affect plant nitrogen (N) dynamics. Plant N isotope patterns have been used to characterise the contribution of ECM fungi to plant N uptake. By quantifying and comparing the effects of an AM and an ECM fungus on growth, N uptake and isotopic composition of one host plant grown at different relative N supply levels, the aim of this study was to improve the mechanistic understanding of natural 15 N abundance patterns in mycorrhizal plants and their underlying causes. Grey alders were inoculated with one ECM fungus or one AM fungus or left non-mycorrhizal. Plants were grown under semi-hydroponic conditions and were supplied with three rates of relative N supply ranging from deficient to luxurious. Neither mycorrhizal fungus increased plant growth or N uptake. AM root colonisation had no effect on whole plant δ 15 N and decreased foliar δ 15 N only under N deficiency. The roots of these plants were 15 N-enriched. ECM root colonisation consistently decreased foliar and whole plant δ 15 N. It is concluded, that both mycorrhizal fungi contributed to plant N uptake into the shoot. Nitrogen isotope fractionation during N assimilation and transformations in fungal mycelia is suggested to have resulted in plants receiving 15 N-depleted N via the mycorrhizal uptake pathways. Negative mycorrhizal growth effects are explained by symbiotic resource trade on carbon and N and decreased direct plant N uptake. Copyright © 2016 Elsevier GmbH. All rights reserved.

Forest canopy uptake of atmospheric nitrogen deposition at eastern U.S. conifer sites: Carbon storage implications?

Science.gov (United States)

Herman Sievering; Ivan Fernandez; John Lee; John Hom; Lindsey Rustad

2000-01-01

Dry deposition determinations, along with wet deposition and throughfall (TF) measurements, at a spruce fir forest in central Maine were used to estimate the effect of atmospherically deposited nitrogen (N) uptake on forest carbon storage. Using nitric acid and particulate N as well as TF ammonium and nitrate data, the growing season (May-October) net canopy uptake of...

Cd Toxicity and Accumulation in Rice Plants Vary with Soil Nitrogen Status and Their Genotypic Difference can be Partly Attributed to Nitrogen Uptake Capacity

Directory of Open Access Journals (Sweden)

Qin DU

2009-12-01

Full Text Available Two indica rice genotypes, viz. Milyang 46 and Zhenshan 97B differing in Cd accumulation and tolerance were used as materials in a hydroponic system consisting of four Cd levels (0, 0.1, 1.0 and 5.0 µmol/L and three N levels (23.2, 116.0 and 232.0 mg/L to study the effects of nitrogen status and nitrogen uptake capacity on Cd accumulation and tolerance in rice plants. N-efficient rice genotype, Zhenshan 97B, accumulated less Cd and showed higher Cd tolerance than N-inefficient rice genotype, Milyang 46. There was consistency between nitrogen uptake capacity and Cd tolerance in rice plants. Increase of N level in solution slightly increased Cd concentration in shoots but significantly increased in roots of both genotypes. Compared with the control at low N level, Cd tolerance in both rice genotypes could be significantly enhanced under normal N level, but no significant difference was observed between the Cd tolerances under normal N (116.0 mg/L and high N (232.0 mg/L conditions. The result proved that genotypic differences in Cd accumulation and toxicity could be, at least in part, attributed to N uptake capacity in rice plants.

In situ EELS and TEM observation of Al implanted with nitrogen ions

International Nuclear Information System (INIS)

Hojou, K.; Furuno, S.; Kushita, K.N.; Otsu, H.; Izui, K.

1995-01-01

Formation processes of Aluminum nitride (AIN) in Aluminum (AI) implanted with nitrogen were examined by in situ EELS and TEM observations during nitrogen ion implantation in an electron microscope at room temperature and 400 deg C. AIN phase was identified both by EDP and EELS after nitrogen ion implantation to 6 x 10 20 (N + )/m 2 . The observed peak (20.8 eV) in EELS spectra was identified as plasmon loss peak of AIN formed in AI. The binding energy of N ls in AI was found to shift by about 4 eV to the lower side with increasing nitrogen-ion fluence. Unreacted AI was also found to remain in the AIN films after high fluence implantation both at room temperature and 400 deg C. (authors). 11 refs., 5 figs., 2 tabs

Azospirillum Inoculation Alters Nitrate Reductase Activity and Nitrogen Uptake in Wheat Plant Under Water Deficit Conditions

OpenAIRE

N. Aliasgharzad, N. Aliasgharzad; Heydaryan, Zahra; Sarikhani, M.R

2014-01-01

Water deficit stress usually diminishes nitrogen uptake by plants. There are evidences that some nitrogen fixing bacteria can alleviate this stress by supplying nitrogen and improving its metabolism in plants. Four Azospirillum strains, A. lipoferum AC45-II, A. brasilense AC46-I, A. irakense AC49-VII and A. irakense AC51-VI were tested for nitrate reductase activity (NRA). In a pot culture experiment using a sandy loam soil, wheat plants (Triticum aestivum L. cv. Sardari) were inoculated with...

Dry matter yield and nitrogen-15 uptake by tomatoes under sodium chloride stress

International Nuclear Information System (INIS)

Pessarakli, M.; Tucker, T.C.

1988-01-01

An absorption study was conducted in nutrient solution with seedlings of tomato (Lycopersicon esculentum Mill; cv. Columbia) to observe the effects of NaCl on ( 15 N) uptake and distribution in plant roots and shoots. The 14-d-old seedlings were grown for 16 d in complete Hoagland solution no. 1, then salinized (except the controls, -0.03 MPa) to -0.3, -0.6, and -0.9 MPa osmotic potentials with NaCl. Nutrient solutions were sampled daily for N loss after addition of 15 NH 4 15 NO 3 to the pots. The cumulative 15 N loss was considered to be absorbed by plants. Lowering the osmotic potential of the culture solution decreased total N uptake at all salinity levels, and 15 N uptake of the plants at medium and high salinity levels. A low level of salinity did not affect 15 N uptake compared with the control. Water uptake and dry matter yield were affected to a greater extent than 15 N absorption. Nitrogen-15 concentration was slightly higher in roots than in shoots

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)

Kurd Ali, F.; Al-Shammaa, M.

2011-01-01

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 15 N 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)

Carbon: Nitrogen Interaction Regulates Expression of Genes Involved in N-Uptake and Assimilation in Brassica juncea L.

Science.gov (United States)

Goel, Parul; Bhuria, Monika; Kaushal, Mamta

2016-01-01

In plants, several cellular and metabolic pathways interact with each other to regulate processes that are vital for their growth and development. Carbon (C) and Nitrogen (N) are two main nutrients for plants and coordination of C and N pathways is an important factor for maintaining plant growth and development. In the present work, influence of nitrogen and sucrose (C source) on growth parameters and expression of genes involved in nitrogen transport and assimilatory pathways was studied in B. juncea seedlings. For this, B. juncea seedlings were treated with four combinations of C and N source viz., N source alone (-Suc+N), C source alone (+Suc-N), with N and C source (+Suc+N) or without N and C source (-Suc-N). Cotyledon size and shoot length were found to be increased in seedlings, when nitrogen alone was present in the medium. Distinct expression pattern of genes in both, root and shoot tissues was observed in response to exogenously supplied N and C. The presence or depletion of nitrogen alone in the medium leads to severe up- or down-regulation of key genes involved in N-uptake and transport (BjNRT1.1, BjNRT1.8) in root tissue and genes involved in nitrate reduction (BjNR1 and BjNR2) in shoot tissue. Moreover, expression of several genes, like BjAMT1.2, BjAMT2 and BjPK in root and two genes BjAMT2 and BjGS1.1 in shoot were found to be regulated only when C source was present in the medium. Majority of genes were found to respond in root and shoot tissues, when both C and N source were present in the medium, thus reflecting their importance as a signal in regulating expression of genes involved in N-uptake and assimilation. The present work provides insight into the regulation of genes of N-uptake and assimilatory pathway in B. juncea by interaction of both carbon and nitrogen. PMID:27637072

Carbon: Nitrogen Interaction Regulates Expression of Genes Involved in N-Uptake and Assimilation in Brassica juncea L.

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Parul Goel

Full Text Available In plants, several cellular and metabolic pathways interact with each other to regulate processes that are vital for their growth and development. Carbon (C and Nitrogen (N are two main nutrients for plants and coordination of C and N pathways is an important factor for maintaining plant growth and development. In the present work, influence of nitrogen and sucrose (C source on growth parameters and expression of genes involved in nitrogen transport and assimilatory pathways was studied in B. juncea seedlings. For this, B. juncea seedlings were treated with four combinations of C and N source viz., N source alone (-Suc+N, C source alone (+Suc-N, with N and C source (+Suc+N or without N and C source (-Suc-N. Cotyledon size and shoot length were found to be increased in seedlings, when nitrogen alone was present in the medium. Distinct expression pattern of genes in both, root and shoot tissues was observed in response to exogenously supplied N and C. The presence or depletion of nitrogen alone in the medium leads to severe up- or down-regulation of key genes involved in N-uptake and transport (BjNRT1.1, BjNRT1.8 in root tissue and genes involved in nitrate reduction (BjNR1 and BjNR2 in shoot tissue. Moreover, expression of several genes, like BjAMT1.2, BjAMT2 and BjPK in root and two genes BjAMT2 and BjGS1.1 in shoot were found to be regulated only when C source was present in the medium. Majority of genes were found to respond in root and shoot tissues, when both C and N source were present in the medium, thus reflecting their importance as a signal in regulating expression of genes involved in N-uptake and assimilation. The present work provides insight into the regulation of genes of N-uptake and assimilatory pathway in B. juncea by interaction of both carbon and nitrogen.

Effect of nitrogen, potassium and lime on soil and manganese availability and uptake by bean

International Nuclear Information System (INIS)

Muraoka, T.; Nascimento Filho, V.F. do; Salvador, J.O.

1982-01-01

A pot experiment was conducted to assess the effect of nitrogen, potassium and lime on the availability of soil Zn and Mn and the absorption of these elements by bean (Phaseolus vulgaris, L.). The TE (Terra Roxa Estruturada) soil, used in this experiment, had been uniformily labelled with 65 Zn and 54 Mn and incubated prior to the seeding. The nitrogen favoured the absorption of manganese and zinc, tripling the manganese content in the plant and increasing by 2.5 fold the Zn content. The potassium also increased significantly the manganese uptake, but did not affect the zinc uptake. In the case of the Zn, however, the effect continued, though with less intensity. The lime alone reduced by almost 5 times the Mn content in the plant and by 50% the Zn content. Based on the results of the soil analysis (pH, CaCl 2 O.5M extractable Mn and EDTA + CaCl 2 extractable Zn) and on the 65 Zn and 54 Mn specific activities, it is suggested that the effets of nitrogen and potassium could be, partly, of synergic nature and that of the lime, due, also partly, to Ca-Mn and Ca-Zn antagonism in the plant. (Author) [pt

Fire effects on the mobilization and uptake of nitrogen by cheatgrass (Bromus tectorum L.)

Science.gov (United States)

Brittany G. Johnson; Dale W. Johnson; Jeanne C. Chambers; Robert R. Blank

2011-01-01

Cheatgrass (Bromus tectorum L.), an invasive annual grass, is displacing native species and causing increased fire frequency in the Great Basin of the southwestern United States. Growth and nitrogen uptake patterns by cheatgrass were examined in a greenhouse study using soils from sites with the same soil type but different fire histories: 1) an area that burned in...

The Effects of Source and Rate of Nitrogen Fertilizer and Irrigation on Nitrogen Uptake of Silage Corn and Residual Soil Nitrate

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M. A. Khodshenas

2016-09-01

Full Text Available Introduction: Growing irrigation demand for corn production, along side with draws of ground water from stressed water sources, should be limited due to scarce resources and environmental protection aspects. Nitrogen fertilizer applied at rates higher than the optimum requirement for crop production may cause an increase in nitrate accumulation below the root zone and pose a risk of nitrate leaching. Improving nitrogen management for corn production has a close relation with soil water content. In this study, we investigated the effects of source and rate of nitrogen fertilizer and irrigation on silage corn production and nitrogen concentration, nitrogen uptake and residual soil nitrate in two depths. Materials and Methods: This experiment carried out as split spli- plot in a Randomized Complete Block design (RCBD with three replications, in Arak station (Agricultural research center of markazi province, 34.12 N, 49.7 E; 1715 m above mean sea level during three years. The soil on the site was classified as a Calcaric Regosols (loamy skeletal over fragmental, carbonatic, thermic, calcixerollic xerochrepts. Main plots were irrigation treatments based on 70, 100 and 130 mm cumulative evaporation from A class Pan. Sub plots were two kinds of nitrogen fertilizers (Urea and Ammonium nitrate and sub sub-plots were five levels of nitrogen rates (0, 100, 200, 300 and 400 kgN.ha-1. Nitrogen fertilizer rates were split into three applications: 1/3 was applied at planting, 1/3 at 7-9 leaf stage and 1/3 remainder was applied before tasseling as a banding method. Phosphorus was applied at a rate of 150 kg.ha-1in each season and potassium at a rate of 30kg.ha-1 (only in first growth season based on soil testing as triple super phosphate and potassium sulfate, respectively. The corn variety of single cross 704 was planted at 20 m2 plots. The plants were sampled at dough stage from the two rows and weighted in each plot. Plant samples were dried in a forced air

Increasing plant use of organic nitrogen with elevation is reflected in nitrogen uptake rates and ecosystem delta15N.

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Averill, Colin; Finzi, Adrien

2011-04-01

It is hypothesized that decreasing mean annual temperature and rates of nitrogen (N) cycling causes plants to switch from inorganic to organic forms of N as the primary mode of N nutrition. To test this hypothesis, we conducted field experiments and collected natural-abundance delta15N signatures of foliage, soils, and ectomycorrhizal sporocarps along a steep elevation-climate gradient in the White Mountains, New Hampshire, USA. Here we show that with increasing elevation organic forms of N became the dominant source of N taken up by hardwood and coniferous tree species based on dual-labeled glycine uptake analysis, an important confirmation of an emerging theory for the biogeochemistry of the N cycle. Variation in natural abundance foliar delta15N with elevation was also consistent with increasing organic N uptake, though a simple, mass balance model demonstrated that the uptake of delta15N depleted inorganic N, rather than fractionation upon transfer of N from mycorrhizal fungi, best explains variations in foliar delta15N with elevation.

Dissolved organic nitrogen recalcitrance and bioavailable nitrogen quantification for effluents from advanced nitrogen removal wastewater treatment facilities

International Nuclear Information System (INIS)

Fan, Lu; Brett, Michael T.; Jiang, Wenju; Li, Bo

2017-01-01

The objective of this study was to determine the composition of nitrogen (N) in the effluents of advanced N removal (ANR) wastewater treatment plants (WWTPs). This study also tested two different experimental protocols for determining dissolved N recalcitrance. An analysis of 15 effluent samples from five WWTPs, showed effluent concentrations and especially effluent composition varied greatly from one system to the other, with total nitrogen (TN) ranging between 1.05 and 8.10 mg L −1 . Nitrate (NO 3 − ) accounted for between 38 ± 32% of TN, and ammonium accounted for a further 29 ± 28%. All of these samples were dominated by dissolved inorganic nitrogen (DIN; NO 3 −  + NH 4 + ), and uptake experiments indicated the DIN fraction was as expected highly bioavailable. Dissolved organic N (DON) accounted for 20 ± 11% for the total dissolved N in these effluents, and uptake experiments indicated the bioavailability of this fraction varied between 27 ± 26% depending on the WWTP assessed. These results indicate near complete DIN removal should be the primary goal of ANR treatment systems. The comparison of bioavailable nitrogen (BAN) quantification protocols showed that the dissolved nitrogen uptake bioassay approach was clearly a more reliable way to determine BAN concentrations compared to the conventional cell yield protocol. Moreover, because the nitrogen uptake experiment was much more sensitive, this protocol made it easier to detect extrinsic factors (such as biological contamination or toxicity) that could affect the accuracy of these bioassays. Based on these results, we recommend the nitrogen uptake bioassay using filtered and autoclaved samples to quantify BAN concentrations. However, for effluent samples indicating toxicity, algal bioassays will not accurately quantify BAN. - Highlights: • DIN was the dominated N pool for most of the tested effluent samples. • DON bioavailability considerably varied depending on the WWTP assessed. �

Nitrogen and Phosphorus Plant Uptake During Periods with no Photosynthesis Accounts for About Half of Global Annual Uptake

Science.gov (United States)

Riley, W. J.; Zhu, Q.; Tang, J.

2017-12-01

Uncertainties in current Earth System Model (ESM) predictions of terrestrial carbon-climate feedbacks over the 21st century are as large as, or larger than, any other reported natural system uncertainties. Soil Organic Matter (SOM) decomposition and photosynthesis, the dominant fluxes in this regard, are tightly linked through nutrient availability, and the recent Coupled Model Inter-comparison Project 5 (CMIP5) used for climate change assessment had no credible representations of these constraints. In response, many ESM land models (ESMLMs) have developed dynamic and coupled soil and plant nutrient cycles. Here we quantify terrestrial carbon cycle impacts from well-known observed plant nutrient uptake mechanisms ignored in most current ESMLMs. In particular, we estimate the global role of plant root nutrient competition with microbes and abiotic process at night and during the non-growing season using the ACME land model (ALMv1-ECA-CNP) that explicitly represents these dynamics. We first demonstrate that short-term nutrient uptake dynamics and competition between plants and microbes are accurately predicted by the model compared to 15N and 33P isotopic tracer measurements from more than 20 sites. We then show that global nighttime and non-growing season nitrogen and phosphorus uptake accounts for 46 and 45%, respectively, of annual uptake, with large latitudinal variation. Model experiments show that ignoring these plant uptake periods leads to large positive biases in annual N leaching (globally 58%) and N2O emissions (globally 68%). Biases these large will affect modeled carbon cycle dynamics over time, and lead to predictions of ecosystems that have overly open nutrient cycles and therefore lower capacity to sequester carbon.

Growth, Carbon Isotope Discrimination and Nitrogen Uptake in Silicon and/or Potassium Fed barley Grown under Two Watering Regimes

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Kurdali, Fawaz

2013-02-01

Full Text Available The present pot experiment was an attempt to monitor the beneficial effects of silicon (Si and/or potassium (K applications on growth and nitrogen uptake in barley plants grown under water (FC1 and non water (FC2 stress conditions using 15N and 13C isotopes. Three fertilizer rates of Si (Si50, Si100 and Si200 and one fertilizer rate of K were used. Dry matter (DM and N yield (NY in different plant parts of barley plants was affected by Si and/ or K fertilization as well as by the watering regime level under which the plants have been grown. Solely added K or in combination with adequate rate of Si (Si 100 were more effective in alleviating water stress and producing higher yield in barley plants than solely added Si. However, the latter nutrient was found to be more effective than the former in producing higher spike's N yield. Solely added Si or in combination with K significantly reduced leaves ∆13 C reflecting their bifacial effects on water use efficiency (WUE, particularly in plants grown under well watering regime. This result indicated that Si might be involved in saving water loss through reducing transpiration rate and facilitating water uptake; consequently, increasing WUE. Although the rising of soil humidity generally increased fertilizer nitrogen uptake (Ndff and its use efficiency (%NUE in barley plants, applications of K or Si fertilizers to water stressed plants resulted in significant increments of these parameters as compared with the control. Our results highlight that Si or K is not only involved in amelioration of growth of barley plants, but can also improve nitrogen uptake and fertilizer nitrogen use efficiency particularly under water deficit conditions.

Sulfur X-Ray Absorption Spectroscopy of Living Mammalian Cells: An Enabling Tool for Sulfur Metabolomics. in Situ Observation of Uptake of Taurine Into MDCK Cells

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Gnida, M.; Sneeden, E.Yu; Whitin, J.C.; Prince, R.C.; Pickering, I.J.; Korbas, M.; George, G.N.

2009-06-01

Sulfur is essential for life, with important roles in biological structure and function. However, because of a lack of suitable biophysical techniques, in situ information about sulfur biochemistry is generally difficult to obtain. Here, we present an in situ sulfur X-ray absorption spectroscopy (S-XAS) study of living cell cultures of the mammalian renal epithelial MDCK cell line. A great deal of information is retrieved from a characteristic sulfonate feature in the X-ray absorption spectrum of the cell cultures, which can be related to the amino acid taurine. We followed the time and dose dependence of uptake of taurine into MDCK cell monolayers. The corresponding uptake curves showed a typical saturation behavior with considerable levels of taurine accumulation inside the cells (as much as 40% of total cellular sulfur). We also investigated the polarity of uptake of taurine into MDCK cells, and our results confirmed that uptake in situ is predominantly a function of the basolateral cell surface.

Interactions between uptake of amino acids and inorganic nitrogen in wheat plants

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E. Gioseffi

2012-04-01

Full Text Available Soil-borne amino acids may constitute a source of nitrogen (N for plants in various terrestrial ecosystems but their importance for total N nutrition is unclear, particularly in nutrient-rich arable soils. One reason for this uncertainty is lack of information on how the absorption of amino acids by plant roots is affected by the simultaneous presence of inorganic N forms. The objective of the present study was to study absorption of glycine (Gly and glutamine (Gln by wheat roots and their interactions with nitrate (NO₃⁻ and ammonium (NH₄⁺ during uptake. The underlying hypothesis was that amino acids, when present in nutrient solution together with inorganic N, may lead to down-regulation of the inorganic N uptake, thereby resulting in similar total N uptake rates. Amino acids were enriched with double-labelled ¹⁵N and ¹³C, while NO₃⁻ and NH₄⁺ acquisition was determined by their rate of removal from the nutrient solution surrounding the roots. The uptake rates of NO₃⁻ and NH₄⁺ did not differ from each other and were generally about twice as high as the uptake rate of organic N when the different N forms were supplied separately in concentrations of 2 mM. Nevertheless, replacement of 50% of the inorganic N with organic N was able to restore the N uptake to the same level as that in the presence of only inorganic N. Co-provision of NO₃⁻ did not affect glycine uptake, while the presence of glycine down-regulated NO₃⁻ uptake. The ratio between ¹³C and ¹⁵N were lower in shoots than in roots and also lower than the theoretical values, reflecting higher C losses via respiratory processes compared to N losses. It is concluded that organic N can constitute a significant N-source for wheat plants and that there is an interaction

Nitrogen uptake by Azospirillum brasilense inoculated barley (Hordeum vulgare L.) as influenced by N and P fertilization

International Nuclear Information System (INIS)

Negi, Mahima; Tilak, K.V.B.R.; Sachdev, M.S.

1991-01-01

Response of barley (Hordeum vulgare L.) in a sandy-loam soil under potted conditions revealed that application of nitrogen and phosphorus increased the population of Azospirillium in the barley rhizosphere. A two fold increase was observed in the Azospirillium population at 80 days compared to that at 40 days of plant growth. The unsterilized inoculated roots had more population than the surface sterilized inoculated roots. Increased drymatter production of barley was obtained in A. brasilense inoculated N 0 P 1 (0 kg N and 30 kg P 2 O 5 ha -1 ) treatment than uninoculated control. Also N and P uptake was higher in A. brasilense inoculated plants in the presence of both N and P fertilizers. The 15 N data revealed that at harvest nearly 36 per cent of the total N uptake was from the nitrogen fixed by A. brasilense irrespective of P treatment. (author). 16 refs., 4 tabs

Coral uptake of inorganic phosphorus and nitrogen negatively affected by simultaneous changes in temperature and pH.

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Claire Godinot

Full Text Available The effects of ocean acidification and elevated seawater temperature on coral calcification and photosynthesis have been extensively investigated over the last two decades, whereas they are still unknown on nutrient uptake, despite their importance for coral energetics. We therefore studied the separate and combined impacts of increases in temperature and pCO(2 on phosphate, ammonium, and nitrate uptake rates by the scleractinian coral S. pistillata. Three experiments were performed, during 10 days i at three pH(T conditions (8.1, 7.8, and 7.5 and normal temperature (26°C, ii at three temperature conditions (26°, 29°C, and 33°C and normal pH(T (8.1, and iii at three pH(T conditions (8.1, 7.8, and 7.5 and elevated temperature (33°C. After 10 days of incubation, corals had not bleached, as protein, chlorophyll, and zooxanthellae contents were the same in all treatments. However, photosynthetic rates significantly decreased at 33°C, and were further reduced for the pH(T 7.5. The photosynthetic efficiency of PSII was only decreased by elevated temperature. Nutrient uptake rates were not affected by a change in pH alone. Conversely, elevated temperature (33°C alone induced an increase in phosphate uptake but a severe decrease in nitrate and ammonium uptake rates, even leading to a release of nitrogen into seawater. Combination of high temperature (33°C and low pH(T (7.5 resulted in a significant decrease in phosphate and nitrate uptake rates compared to control corals (26°C, pH(T = 8.1. These results indicate that both inorganic nitrogen and phosphorus metabolism may be negatively affected by the cumulative effects of ocean warming and acidification.

Coral Uptake of Inorganic Phosphorus and Nitrogen Negatively Affected by Simultaneous Changes in Temperature and pH

Science.gov (United States)

Godinot, Claire; Houlbrèque, Fanny

2011-01-01

The effects of ocean acidification and elevated seawater temperature on coral calcification and photosynthesis have been extensively investigated over the last two decades, whereas they are still unknown on nutrient uptake, despite their importance for coral energetics. We therefore studied the separate and combined impacts of increases in temperature and pCO2 on phosphate, ammonium, and nitrate uptake rates by the scleractinian coral S. pistillata. Three experiments were performed, during 10 days i) at three pHT conditions (8.1, 7.8, and 7.5) and normal temperature (26°C), ii) at three temperature conditions (26°, 29°C, and 33°C) and normal pHT (8.1), and iii) at three pHT conditions (8.1, 7.8, and 7.5) and elevated temperature (33°C). After 10 days of incubation, corals had not bleached, as protein, chlorophyll, and zooxanthellae contents were the same in all treatments. However, photosynthetic rates significantly decreased at 33°C, and were further reduced for the pHT 7.5. The photosynthetic efficiency of PSII was only decreased by elevated temperature. Nutrient uptake rates were not affected by a change in pH alone. Conversely, elevated temperature (33°C) alone induced an increase in phosphate uptake but a severe decrease in nitrate and ammonium uptake rates, even leading to a release of nitrogen into seawater. Combination of high temperature (33°C) and low pHT (7.5) resulted in a significant decrease in phosphate and nitrate uptake rates compared to control corals (26°C, pHT = 8.1). These results indicate that both inorganic nitrogen and phosphorus metabolism may be negatively affected by the cumulative effects of ocean warming and acidification. PMID:21949839

Effect of straw application on nitrogen uptake and growth of rice

International Nuclear Information System (INIS)

Haryanto; Idawati.

1990-01-01

A pot experiment has been conducted to know the effect of straw application on the efficiency of nitrogen uptake and growth rice plant. The rice straw was applied at different time i.e. 0, 1, 2, 3 and 4 weeks before tranplanting. Soil without rice straw was used as control. Thirty gram of rice straw having 3.61 percent of N-15 atom excess was incorporated into 6 kg of latosol soil originated from Pasar jumat, in which Atomoita I, a lowland rice variety, was planted. Urea was given once at the tranplanting time. The result showed that the longer the time of the rice straw application prior to the transplanting time, the higher the N-straw uptake efficiency in the rice plant at any different stages. The highest efficiency was 6.14 percent, reached with straw applicaions at 4 weeks before tranplanting. Compared to the control, straw applications 2 weeks or more before tranplanting resulted in higher grain production, while application at or before 2 weeks of tranplanting produced lower production. (authors). 9 refs.; 5 tabs

Thermal expansion and phase transformations of nitrogen-expanded austenite studied with in situ synchrotron X-ray diffraction

DEFF Research Database (Denmark)

Brink, Bastian; Ståhl, Kenny; Christiansen, Thomas Lundin

2014-01-01

Nitrogen-expanded austenite, _N, with high and low nitrogen contents was produced from AISI 316 grade stainless steel powder by gaseous nitriding in ammonia/hydrogen gas mixtures. In situ synchrotron X-ray diffraction was applied to investigate the thermal expansion and thermal stability...... as a fitting parameter. The stacking fault density is constant for temperatures up to 680 K, whereafter it decreases to nil. Surprisingly, a transition phase with composition M4N (M = Fe, Cr, Ni, Mo) appears for temperatures above 770 K. The linear coefficient of thermal expansion depends on the nitrogen...

Uptake of pulse injected nitrogen by soil microbes and mycorrhizal and non-mycorrhizal plants in a species-diverse subarctic heath ecosystem

DEFF Research Database (Denmark)

Andresen, Louise Christoffersen; Jonasson, Sven; Strom, Lena

2008-01-01

15N labeled ammonium, glycine or glutamic acid was injected into subarctic heath soil in situ, with the purpose of investigating how the nitrogen added in these pulses was subsequently utilized and cycled in the ecosystem. We analyzed the acquisition of 15N label in mycorrhizal and non-mycorrhiza......15N labeled ammonium, glycine or glutamic acid was injected into subarctic heath soil in situ, with the purpose of investigating how the nitrogen added in these pulses was subsequently utilized and cycled in the ecosystem. We analyzed the acquisition of 15N label in mycorrhizal and non...

Effect of soil-moisture stress on nitrogen uptake and fixation by plants

International Nuclear Information System (INIS)

Mitrosuhardjo, M.M.

1983-01-01

The effect of four levels of soil moisture, namely 25, 30, 35, and 40% (g/g) on nitrogen uptake and fixation by plants was studied in a greenhouse experiment. Soybean and wheat were used in this experiment. Both crops were grown in pots containing 7 kg loamy alluvial soil. Rhizobium japonicum was used as an inoculant for soybean, one week after planting. Nitrogen-15 labelled urea with 10% atom excess was applied to each pot with a dose rate of 70 mg N/pot (20 kg N/ha) two weeks after planting. Soil moisture was regularly controlled with porous-cup mercury tensiometers, and the amount of water consumed by plants was always recorded. Water was applied to each pot with a distribution pipe which was laid down in the centre of the soil depth, horizontally in a circular form, and was connected with a smaller pipe to the soil surface. The result obtained showed that the amount of water consumed by plants grown in a higher level of soil moisture was increased until soil aeration problems arose. A different amount of water consumption between soybean and wheat was observed at least until a certain period of growing time. Fertilizer nitrogen taken up by both crops varied with the different levels of soil moisture. Generally, greater fertilizer nitrogen was taken up by both crops grown in a higher level of soil moisture. The symbiotic fixation of nitrogen was reasonable, although no clarification has been found about the role of the four levels of soil-moisture treatment on it. A similar effect of soil-moisture stress on nodule dry matter and acetylene reduction was found. (author)

Genetic variability in uptake of nitrogen at various growth stages of barley and wheat under dryland conditions

International Nuclear Information System (INIS)

Della, A.; Hadjichristodoulou, A.

1976-01-01

Protein and dry matter in a number of high protein and commercial varieties of barley and wheat were tested at various growth stages and at two locations. Large genetic variability was found in uptake of nitrogen, which was taken up generally before heading. High protein yields were not associated with high protein content but with higher dry matter yields. Nitrogen fertilization increased protein content and protein yield at a low protein location only. It was concluded that it is possible to breed for both high grain and high straw protein varieties. (author)

Dissolved organic nitrogen recalcitrance and bioavailable nitrogen quantification for effluents from advanced nitrogen removal wastewater treatment facilities.

Science.gov (United States)

Fan, Lu; Brett, Michael T; Jiang, Wenju; Li, Bo

2017-10-01

The objective of this study was to determine the composition of nitrogen (N) in the effluents of advanced N removal (ANR) wastewater treatment plants (WWTPs). This study also tested two different experimental protocols for determining dissolved N recalcitrance. An analysis of 15 effluent samples from five WWTPs, showed effluent concentrations and especially effluent composition varied greatly from one system to the other, with total nitrogen (TN) ranging between 1.05 and 8.10 mg L -1 . Nitrate (NO 3 - ) accounted for between 38 ± 32% of TN, and ammonium accounted for a further 29 ± 28%. All of these samples were dominated by dissolved inorganic nitrogen (DIN; NO 3 -  + NH 4 + ), and uptake experiments indicated the DIN fraction was as expected highly bioavailable. Dissolved organic N (DON) accounted for 20 ± 11% for the total dissolved N in these effluents, and uptake experiments indicated the bioavailability of this fraction varied between 27 ± 26% depending on the WWTP assessed. These results indicate near complete DIN removal should be the primary goal of ANR treatment systems. The comparison of bioavailable nitrogen (BAN) quantification protocols showed that the dissolved nitrogen uptake bioassay approach was clearly a more reliable way to determine BAN concentrations compared to the conventional cell yield protocol. Moreover, because the nitrogen uptake experiment was much more sensitive, this protocol made it easier to detect extrinsic factors (such as biological contamination or toxicity) that could affect the accuracy of these bioassays. Based on these results, we recommend the nitrogen uptake bioassay using filtered and autoclaved samples to quantify BAN concentrations. However, for effluent samples indicating toxicity, algal bioassays will not accurately quantify BAN. Copyright © 2017 Elsevier Ltd. All rights reserved.

In Situ Denitrification and Biological Nitrogen Fixation Under Enhanced Atmospheric Reactive Nitrogen Deposition in UK Peatlands

Science.gov (United States)

Ullah, Sami; Saiz Val, Ernesto; Sgouridis, Fotis; Peichl, Matthias; Nilsson, Mats

2017-04-01

Dinitrogen (N2) and nitrous oxide (N2O) losses due to denitrification and biological N2 fixation (BNF) are the most uncertain components of the nitrogen (N) cycle in peatlands under enhanced atmospheric reactive nitrogen (Nr) deposition. This uncertainty hampers our ability to assess the contribution of denitrification to the removal of biologically fixed and/or atmospherically deposited Nr in peatlands. This uncertainty emanates from the difficulty in measuring in situ soil N2 and N2O production and consumption in peatlands. In situ denitrification and its contribution to total N2O flux was measured monthly between April 2013 and October 2014 in peatlands in two UK catchments. An adapted 15N-Gas Flux method1 with low level addition of 15N tracer (0.03 ± 0.005 kg 15N ha-1) was used to measure denitrification and its contribution to net N2O production (DN2O/TN2O). BNF was measured in situ through incubation of selected sphagnum species under 15N2 gas tracer. Denitrification2 varied temporally and averaged 8 kg N-N2 ha-1 y-1. The contribution of denitrification was about 48% to total N2O flux3 of 0.05 kg N ha-1 y-1. Soil moisture, temperature, ecosystem respiration, pH and mineral N content mainly regulated the flux of N2 and N2O. Preliminary results showed suppression of BNF, which was 1.8 to 7 times lower in peatland mosses exposed to ˜15 to 20 kg N ha-1 y-1 Nr deposition in the UK than in peatland mosses in northern Sweden with background Nr deposition. Overall, the contribution of denitrification to Nr removal in the selected peatlands was ˜50% of the annual Nr deposition rates, making these ecosystems vulnerable to chronic N saturation. These results point to a need for a more comprehensive annual BNF measurement to more accurately account for total Nr input into peatlands and its atmospheric loss due to denitrification. References Sgouridis F, Stott A & Ullah S, 2016. Application of the 15N-Gas Flux method for measuring in situ N2 and N2O fluxes due to

Seasonal temperatures have more influence than nitrogen fertilizer rates on cucumber yield and nitrogen uptake in a double cropping system

Energy Technology Data Exchange (ETDEWEB)

Guo Ruiying; Li Xiaolin [College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan Xilu, Haidian District, Beijing 100094 (China); Christie, Peter [College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan Xilu, Haidian District, Beijing 100094 (China); Agricultural and Environmental Science Department, Queen' s University Belfast, Belfast BT9 5PX (United Kingdom); Chen Qing [College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan Xilu, Haidian District, Beijing 100094 (China)], E-mail: qchen@cau.edu.cn; Zhang Fusuo [College of Resources and Environmental Sciences, China Agricultural University, No. 2 Yuanmingyuan Xilu, Haidian District, Beijing 100094 (China)

2008-02-15

Two-year greenhouse cucumber experiments were conducted to investigate seasonal effects on fruit yield, dry matter allocation, and N uptake in a double-cropping system with different fertilizer management. Seasonal effects were much greater than fertilizer effects, and winter-spring (WS) cucumber attained higher fruit yields and N uptake than autumn-winter (AW) cucumber due to lower cumulative air temperatures during fruit maturation in the AW season. Fertilizer N application and apparent N loss under recommended N management (Nmr) decreased by 40-78% and 33-48% without yield loss compared to conventional N management (Nmt) over four growing seasons. However, there were no seasonal differences in N recommendations, taking into consideration seasonal differences in crop N demand, critical nutrient supply in the root zone and N mineralization rate. - Nitrogen inputs can be reduced to minimize N losses to the environment while maintaining yields but N recommendations must reflect seasonal temperature effects.

Seasonal temperatures have more influence than nitrogen fertilizer rates on cucumber yield and nitrogen uptake in a double cropping system

International Nuclear Information System (INIS)

Guo Ruiying; Li Xiaolin; Christie, Peter; Chen Qing; Zhang Fusuo

2008-01-01

Two-year greenhouse cucumber experiments were conducted to investigate seasonal effects on fruit yield, dry matter allocation, and N uptake in a double-cropping system with different fertilizer management. Seasonal effects were much greater than fertilizer effects, and winter-spring (WS) cucumber attained higher fruit yields and N uptake than autumn-winter (AW) cucumber due to lower cumulative air temperatures during fruit maturation in the AW season. Fertilizer N application and apparent N loss under recommended N management (Nmr) decreased by 40-78% and 33-48% without yield loss compared to conventional N management (Nmt) over four growing seasons. However, there were no seasonal differences in N recommendations, taking into consideration seasonal differences in crop N demand, critical nutrient supply in the root zone and N mineralization rate. - Nitrogen inputs can be reduced to minimize N losses to the environment while maintaining yields but N recommendations must reflect seasonal temperature effects

Arbuscular mycorrhiza improve growth, nitrogen uptake, and nitrogen use efficiency in wheat grown under elevated CO2.

Science.gov (United States)

Zhu, Xiancan; Song, Fengbin; Liu, Shengqun; Liu, Fulai

2016-02-01

Effects of the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis on plant growth, carbon (C) and nitrogen (N) accumulation, and partitioning was investigated in Triticum aestivum L. plants grown under elevated CO2 in a pot experiment. Wheat plants inoculated or not inoculated with the AM fungus were grown in two glasshouse cells with different CO2 concentrations (400 and 700 ppm) for 10 weeks. A (15)N isotope labeling technique was used to trace plant N uptake. Results showed that elevated CO2 increased AM fungal colonization. Under CO2 elevation, AM plants had higher C concentration and higher plant biomass than the non-AM plants. CO2 elevation did not affect C and N partitioning in plant organs, while AM symbiosis increased C and N allocation into the roots. In addition, plant C and N accumulation, (15)N recovery rate, and N use efficiency (NUE) were significantly higher in AM plants than in non-AM controls under CO2 enrichment. It is concluded that AM symbiosis favors C and N partitioning in roots, increases C accumulation and N uptake, and leads to greater NUE in wheat plants grown at elevated CO2.

Light Conditions Affect the Measurement of Oceanic Bacterial Production via Leucine Uptake

Science.gov (United States)

Morán, Xosé Anxelu G.; Massana, Ramon; Gasol, Josep M.

2001-01-01

The effect of irradiance in the range of 400 to 700 nm or photosynthetically active radiation (PAR) on bacterial heterotrophic production estimated by the incorporation of 3H-leucine (referred to herein as Leu) was investigated in the northwestern Mediterranean Sea and in a coastal North Atlantic site, with Leu uptake rates ranging over 3 orders of magnitude. We performed in situ incubations under natural irradiance levels of Mediterranean samples taken from five depths around solar noon and compared them to incubations in the dark. In two of the three stations large differences were found between light and dark uptake rates for the surfacemost samples, with dark values being on average 133 and 109% higher than in situ ones. Data obtained in coastal North Atlantic waters confirmed that dark enclosure may increase Leu uptake rates more than threefold. To explain these differences, on-board experiments of Leu uptake versus irradiance were performed with Mediterranean samples from depths of 5 and 40 m. Incubations under a gradient of 12 to 1,731 μmol of photons m−2 s−1 evidenced a significant increase in incorporation rates with increasing PAR in most of the experiments, with dark-incubated samples departing from this pattern. These results were not attributed to inhibition of Leu uptake in the light but to enhanced bacterial response when transferred to dark conditions. The ratio of dark to light uptake rates increased as dissolved inorganic nitrogen concentrations decreased, suggesting that bacterial nutrient deficiency was overcome by some process occurring only in the dark bottles. PMID:11525969

EFFECT OF IRRIGATION WITH SEWAGE WASTEWATER ON NITROGEN UPTAKE AND TRANSLOCATION BY NAVEL ORANGE TRANSPLANTS USING 15N-LABELLED AMMONIUM SULPHATE

International Nuclear Information System (INIS)

EL-MOTAIUM, R.A.; SHARAF, A.N.; HASHEM, M.E.; HEGAZI, E.S.; BADAWY, S.H.

2009-01-01

An isotope aided study using 15 N-labelled ammonium sulphate was applied to investigate nitrogen uptake and translocation from sewage water by one year old Navel orange transplants. The investigation was conducted in a pot experiment at the greenhouse for two successive seasons (2005 and 2006). Ammonium sulphate was applied to the soil at a rate of 6 g/pot. The treatments included irrigation with canal water and sewage water. Half strength Hoagland nutrient solution, nitrogen depleted, was applied to provide the required nutrients for healthy growth of the transplants. The pots were irrigated to maintain the soil moisture content at field capacity.The results indicated that there is an increase in the transplants biomass irrigated with sewage water than using canal water. A substantial increase in mineral fertilizer nitrogen ( 15 N) uptake by plant roots and translocation into shoots was observed using canal water than sewage water. The nitrogen percent derived from sewage water was higher (26.1-49.5%) than that derived from 15 N-labelled ammonium sulphate (4.9-12.7%). Fertilizer nitrogen recovery was higher under canal water than under sewage water irrigation regime, although the plant biomass was higher under sewage water. Using sewage water alone can provide the orange transplants with their nitrogen requirements with no need for application of mineral fertilizer

Effects of land-applied ammonia scrubber solutions on yield, nitrogen uptake, soil test phosphorus and phosphorus runoff

Science.gov (United States)

Ammonia (NH3) scrubbers reduce amounts of NH3 and dust released from animal rearing facilities, while generating nitrogen (N) rich solutions, which may be used as fertilizer. The objective of this study was to determine the effects of various NH3 scrubber solutions on yields, N uptake by forage, so...

Comparative effects of partial root-zone drying and deficit irrigation on nitrogen uptake in potatoes (Solanum tuberosum L.)

DEFF Research Database (Denmark)

Wang, Huiqun; Liu, Fulai; Andersen, Mathias Neumann

2009-01-01

The effects of partial root-zone drying (PRD) as compared with deficit irrigation (DI) and full irrigation (FI) on nitrogen (N) uptake and partitioning in potato (Solanum tuberosum L.) were investigated. Potato plants were grown in split-root pots and were exposed to FI, PRD, and DI treatments...

INTERACTIONS BETWEEN SOIL TEMPERATURE AND PLANT GROWTH STAGE ON NITROGEN UPTAKE AND AMINO ACID CONTENT OF APPLE NURSERY STOCK DURING EARLY SPRING GROWTH

Science.gov (United States)

In the spring, nitrogen (N) uptake by apple roots is known to be delayed about three weeks after bud break. We used one-year-old 'Fuji' (Malus domestica Borkh) on M26 bare-root apple trees to determine whether timing of N uptake in the spring is dependant solely on the growth st...

In Situ Activation of Nitrogen-Doped Graphene Anchored on Graphite Foam for a High-Capacity Anode.

Science.gov (United States)

Ji, Junyi; Liu, Jilei; Lai, Linfei; Zhao, Xin; Zhen, Yongda; Lin, Jianyi; Zhu, Yanwu; Ji, Hengxing; Zhang, Li Li; Ruoff, Rodney S

2015-08-25

We report the fabrication of a three-dimensional free-standing nitrogen-doped porous graphene/graphite foam by in situ activation of nitrogen-doped graphene on highly conductive graphite foam (GF). After in situ activation, intimate "sheet contact" was observed between the graphene sheets and the GF. The sheet contact produced by in situ activation is found to be superior to the "point contact" obtained by the traditional drop-casting method and facilitates electron transfer. Due to the intimate contact as well as the use of an ultralight GF current collector, the composite electrode delivers a gravimetric capacity of 642 mAh g(-1) and a volumetric capacity of 602 mAh cm(-3) with respect to the whole electrode mass and volume (including the active materials and the GF current collector). When normalized based on the mass of the active material, the composite electrode delivers a high specific capacity of up to 1687 mAh g(-1), which is superior to that of most graphene-based electrodes. Also, after ∼90 s charging, the anode delivers a capacity of about 100 mAh g(-1) (with respect to the total mass of the electrode), indicating its potential use in high-rate lithium-ion batteries.

Nitrogen nutrition of Salvinia natans: Effects of inorganic nitrogen form on growth, morphology, nitrate reductase activity and uptake kinetics of ammonium and nitrate

DEFF Research Database (Denmark)

Jampeetong, Arunothai; Brix, Hans

2009-01-01

In this study we assessed the growth, morphological responses, and N uptake kinetics of Salvinia natans when supplied with nitrogen as NO3-, NH4+, or both at equimolar concentrations (500 μM). Plants supplied with only NO3- had lower growth rates (0.17 ± 0.01 g g-1 d-1), shorter roots, smaller...... leaves with less chlorophyll than plants supplied with NH4+ alone or in combination with NO3- (RGR = 0.28 ± 0.01 g g-1 d-1). Ammonium was the preferred form of N taken up. The maximal rate of NH4+ uptake (Vmax) was 6-14 times higher than the maximal uptake rate of NO3- and the minimum concentration...... for uptake (Cmin) was lower for NH4+ than for NO3-. Plants supplied with NO3- had elevated nitrate reductase activity (NRA) particularly in the roots showing that NO3- was primarily reduced in the roots, but NRA levels were generally low (NH4...

Characterization of Nitrogen Uptake Pattern in Malaysian Rice MR219 at Different Growth Stages Using 15N Isotope

Directory of Open Access Journals (Sweden)

Mohammad Mu’az Hashim

2015-09-01

Full Text Available Nitrogen (N use efficiency is usually less than 50%, and it remains a major problem in rice cultivation. Controlled release fertilizer (CRF technology is one of the well-known efforts to overcome this problem. The efficiency of CRF, however, is very much dependent on the timing of nutrient release. This study was conducted to determine the precise time of N uptake by rice as a guideline to develop efficient CRF. Fertilizer N uptake by rice at different growth stages was investigated by using 15N isotopic technique. Rice was planted in pots, with 15N urea as N source at the rate of 120 kg/hm2. Potassium and phosphorus were applied at the same rate of 50 kg/hm2. Standard agronomic practices were employed throughout the growing periods. Rice plants were harvested every two weeks until maturation at the 14th week and analyzed for total N and 15N content. Nitrogen derived from fertilizer was calculated. Total N uptake in plants consistently increased until the 11th week. After that, it started to plateau and finally declined. Moreover, N utilization by rice plants peaked at 50%, which occurred during the 11th week after transplanting. N derived from fertilizer in rice plants were in the range of 18.7% to 40.0% in all plant tissues. The remaining N was derived from soil. Based on this study, N release from CRF should complete by the 11th week after planting to ensure the maximum fertilizer N uptake by rice plants. Efficient CRF should contribute to higher N derived from fertilizer which also resultedin a higher total N uptake by rice plants, increasing the potential of rice to produce higher yield while at the same time of reducing loss.

Nitrogen uptake and balance of the fertilizers urea, urea with urease inhibitor, and ammonium nitrate applied to spring wheat at stem elongation growth stage

International Nuclear Information System (INIS)

Matzel, W.; Lippold, H.; Heber, R.

1979-01-01

The use of urea containing 1% of diamido phosphoric acid phenyl ester, which is a urease inhibitor, for the top dressing of spring wheat on light soil allows the loss of nitrogen due to volatilization of ammonia from urea to be prevented. The urease inhibitor has no effect whatsoever upon the uptake of urea nitrogen by spring wheat. Even in those cases where the volatilization of ammonia is prevented, plants will take up 5 to 6% less nitrogen from urea than from ammonium nitrate. This is due primarily to the higher degree of immobilization of urea nitrogen in the soil. The volatilization of ammonia from urea applied to the surface of the soil was in the region of 25% when the soil surface was moist and 10% when the soil surface was dry, the percentages given above being related to the amount of fertilizer nitrogen applied to the soil. The plant uptake of fertilizer nitrogen applied as a second dose at stem elongation will be complete after two to three weeks or after six weeks under favourable or unfavourable conditions, respectively. Proceeding immediately after application of the fertilizer nitrogen are the processes resulting in both loss of nitrogen and its immobilization. The proportion of absorbed fertilizer nitrogen recovered in the grain will be the greater the later the nitrogen is incorporated into the plant. The use in pot experiments of labelled nitrogen fertilizers enables statistically significant differences in effects to be determined even in those cases in which the differences are only relatively small in degree. (author)

The use of the short-lived radioisotopes 11C and 13N to study nitrogen uptake and photosynthate translocation in fodder beet

International Nuclear Information System (INIS)

McNaughton, G.S.; Minchin, P.E.H.

1983-01-01

Following discussions at the Nitrogen Balance Workshop held at Massey University, May 1980, on the use of the 10 min half-life isotope nitrogen-13, it was decided to carry out collaborative experiments with Dr K.M. Goh from Lincoln College. These were concerned with the mechanism of the effect of sodium chloride on the uptake of nitrate and ammonium ions by beet (Beta vulgaris L) plants. In this report we firstly summarize briefly some of the relevant literature then report on the experiments carried out to November 1982. The initial experiments used nitrogen-13 to investigate, with hydroponically grown plants, the effect of sodium chloride on the uptake by roots, and the transport to leaves, of nitrogen-13 applied to the roots as nitrate or as ammonium ions. After failing to find any response to NaCl in these experiments, it was decided to determine whether there was any effect of NaC1 on the transport of carbon-11 labelled photosynthates from the leaves. Production of this preliminary report is a first step to assessing the next phase, if any of this investigation

Nutrient uptake dynamics across a gradient of nutrient concentrations and ratios at the landscape scale

Science.gov (United States)

Gibson, Catherine A.; O'Reilly, Catherine M.; Conine, Andrea L.; Lipshutz, Sondra M.

2015-02-01

Understanding interactions between nutrient cycles is essential for recognizing and remediating human impacts on water quality, yet multielemental approaches to studying nutrient cycling in streams are currently rare. Here we utilized a relatively new approach (tracer additions for spiraling curve characterization) to examine uptake dynamics for three essential nutrients across a landscape that varied in absolute and relative nutrient availability. We measured nutrient uptake for soluble reactive phosphorous, ammonium-nitrogen, and nitrate-nitrogen in 16 headwater streams in the Catskill Mountains, New York. Across the landscape, ammonium-nitrogen and soluble reactive phosphorus had shorter uptake lengths and higher uptake velocities than nitrate-nitrogen. Ammonium-nitrogen and soluble reactive phosphorus uptake velocities were tightly correlated, and the slope of the relationship did not differ from one, suggesting strong demand for both nutrients despite the high ambient water column dissolved inorganic nitrogen: soluble reactive phosphorus ratios. Ammonium-nitrogen appeared to be the preferred form of nitrogen despite much higher nitrate-nitrogen concentrations. The uptake rate of nitrate-nitrogen was positively correlated with ambient soluble reactive phosphorus concentration and soluble reactive phosphorus areal uptake rate, suggesting that higher soluble reactive phosphorus concentrations alleviate phosphorus limitation and facilitate nitrate-nitrogen uptake. In addition, these streams retained a large proportion of soluble reactive phosphorus, ammonium-nitrogen, and nitrate-nitrogen supplied by the watershed, demonstrating that these streams are important landscape filters for nutrients. Together, these results (1) indicated phosphorus limitation across the landscape but similarly high demand for ammonium-nitrogen and (2) suggested that nitrate-nitrogen uptake was influenced by variability in soluble reactive phosphorus availability and preference for

Using 15N in studies on the uptake of mineral and organic nitrogen by plants

International Nuclear Information System (INIS)

Mitovska, R.

1983-01-01

Modelled microplot field experiments at the Central Experimental Station of the All-Union Institute of Fertilizers and Agrochemistry in Moscow were used to study the uptake of nitrogen ( 15 N) applied together or individually with minerals or with green oats mass or in both ways. The studies were conducted on soddy podzolic, heavy loam, soddy podzolic sandy soil and leached chernozem. It was established that the soddy podzolic heavy loam had the highest natural fertility and showed greatest response to the applied N

Nitrogen-15 Uptake by Pinus contorta Seedlings in Relation to Phenological Stage and Season

International Nuclear Information System (INIS)

Amponsah, Isaac G.; Lieffers, Victor J.; Comeau, Philip G.; Landhaeusser, Simon M.

2004-01-01

This study measured the amount of uptake of labeled nitrogen ( 15 N) of lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm) seedlings, at three different phenological stages, in a growth chamber experiment. Thirty days after 15 N application, the amount of 15 N recovered in seedlings as a percentage of the total 15 N fertilizer applied was 4% in early spring, 43% in summer and 33% in autumn. The total 15 N recovered in the plant-pot system ranged from 80 to 96%, and is higher than reported in other studies. Total 15 N recovered from the pot compartment alone ranged from 48 to 95%, suggesting that substantial pools of N remain in the soil. Results suggest that low 15 N uptake in the spring was associated with limited development of new root as a result of low spring soil temperatures. The lack of unsuberized roots in spring could be a key factor decreasing the effectiveness of early spring fertilization in the boreal forest

Investigation on the Assimilation of Nitrogen by Maize Roots and the Transport of Some Major Nitrogen Compounds by Xylem Sap

DEFF Research Database (Denmark)

Ivanko, S.; Ingversen, J.

1971-01-01

The uptake and assimilation of nitrate and ammonia have been studied in Zea mays. Nitrogen-starved maize roots are capable of accumulating a potential capacity for nitrogen uptake and assimilation. Reestablishment of nitrogen supply leads to intense uptake, reaching 154 % of the reference variant...... level after 24 hours when nitrate is supplied, and 121 % when ammonia is supplied. After 24 hours the insoluble nitrogen fraction accounts for 80, 54 and 55 % of the total taken up in the PK + NO3-, PK + NH4+ and NPK variants respectively....

Genotypic variation of nitrogen use efficiency in Indian mustard

International Nuclear Information System (INIS)

Ahmad, Altaf; Khan, Ishrat; Abrol, Yash P.; Iqbal, Muhammad

2008-01-01

This experiment was conducted to investigate the variation of nitrogen efficiency (NE), nitrogen uptake efficiency (UE), physiological nitrogen use efficiency (PUE) among Indian mustard genotypes, grown under N-insufficient and N-sufficient conditions. Nitrogen efficiency varied from 52.7 to 92.8. Seed yield varied from 1.14 t ha -1 to 3.21 t ha -1 under N-insufficient condition, while 2.14 t ha -1 -3.33 t ha -1 under N-sufficient condition. Physiological basis of this difference was explained in terms of nitrogen uptake efficiency and physiological nitrogen use efficiency, and their relationship with the growth and yield characteristics. While nitrogen uptake efficiency was positively correlated with plant biomass (0.793**), leaf area index (0.664*), and leaf nitrogen content (0.783**), physiological nitrogen use efficiency is positively correlated with photosynthetic rate (0.689**) and yield (0.814**). This study suggests that genotype having high nitrogen uptake efficiency and high physiological nitrogen use efficiency might help in reducing the nitrogen load on soil without any penalty on the yield. - Nitrogen efficient crop plants may help in reducing environmental contamination of nitrate without any penalty on seed yield

Influence of soil moisture on uptake and utilization of applied nitrogen in tea

International Nuclear Information System (INIS)

Marimuthu, S.; Raj Kumar, R.

1999-01-01

An experiment was conducted with pot-grown young tea plants to study N uptake under different soil moisture regime. Labelled urea nitrogen was found effectively utilized under rainfed conditions. However, N loss through percolation/leaching in response to saturated moisture was as high as 33.3%. Plants grown under controlled conditions utilized less amount of applied N and the rest was retained in the soil. Unaccounted loss, in both the cases, was approximately 9%. Fertilizer-use efficiency of young tea plants under rain fed conditions was about 35% while it was 15% under moisture deficient conditions. Results on N balance in tea soils are discussed. (author)

Nitrate transporters in leaves and their potential roles in foliar uptake of nitrogen dioxide

Directory of Open Access Journals (Sweden)

Yanbo eHu

2014-07-01

Full Text Available While plant roots are specialized organs for the uptake and transport of water and nutrients, the absorption of gaseous or liquid mineral elements by aerial plant parts has been recognized since more than one century. Nitrogen (N is an essential macronutrient which generally absorbed either as nitrate (NO3- or ammonium (NH4+ by plant roots. Gaseous nitrogen pollutants like N dioxide (NO2 can also be absorbed by plant surfaces and assimilated via the NO3– assimilation pathway. The subsequent NO3– flux may induce or repress the expression of various NO3–-responsive genes encoding for instance, the transmembrane transporters, NO3–/NO2– (nitrite reductase, or assimilatory enzymes involved in N metabolism. Based on the existing information, the aim of this review was to theoretically analyze the potential link between foliar NO2 absorption and N transport and metabolism. For such purpose, an overview of the state of knowledge on the NO3– transporter genes identified in leaves or shoots of various species and their roles for NO3– transport across the tonoplast and plasma membrane, in addition to the process of phloem loading is briefly provided. It is assumed that a NO2-induced ac-cumulation of NO3–/NO2– may alter the expression of such genes, hence linking transmembrane NO3– transporters and foliar uptake of NO2. It is likely that NRT1/NRT2 gene expression and spe-cies-dependent apoplastic buffer capacity may be also related to the species-specific foliar NO2 uptake process. It is concluded that further work focusing on the expression of NRT1 (NRT1.1, NRT1.7, NRT1.11 and NRT1.12, NRT2 (NRT2.1, NRT2.4 and NRT2.5 and chloride channel family genes (CLCa and CLCd may help us elucidate the physiological and metabolic response of plants fumigated with NO2.

Arbuscular mycorrhiza improve growth, nitrogen uptake, and nitrogen use efficiency in wheat grown under elevated CO2

DEFF Research Database (Denmark)

Zhu, Xiancan; Song, Fengbin; Liu, Shengqun

2016-01-01

Effects of the arbuscular mycorrhizal (AM) fungus Rhizophagus irregularis on plant growth, carbon (C) and nitrogen (N) accumulation, and partitioning was investigated in Triticum aestivum L. plants grown under elevated CO2 in a pot experiment. Wheat plants inoculated or not inoculated with the AM...... and higher plant biomass than the non-AM plants. CO2 elevation did not affect C and N partitioning in plant organs, while AM symbiosis increased C and N allocation into the roots. In addition, plant C and N accumulation, (15)N recovery rate, and N use efficiency (NUE) were significantly higher in AM plants...... than in non-AM controls under CO2 enrichment. It is concluded that AM symbiosis favors C and N partitioning in roots, increases C accumulation and N uptake, and leads to greater NUE in wheat plants grown at elevated CO2....

Effect of long-term drought on carbon allocation and nitrogen uptake of Pinus sylvestris seedlings

Science.gov (United States)

Pumpanen, Jukka; Aaltonen, Heidi; Lindén, Aki; Köster, Kajar; Biasi, Christina; Heinonsalo, Jussi

2015-04-01

Weather extremes such as drought events are expected to increase in the future as a result of climate change. The drought affects the allocation of carbon assimilated by plants e.g. by modifying the root to shoot ratio, amount of fine roots and the amount of mycorrhizal fungal hyphae. We studied the effect of long term drought on the allocation of carbon in a common garden experiment with 4-year-old Pinus sylvestris seedlings. Half of the seedlings were exposed to long-term drought by setting the soil water content close to wilting point for over two growing seasons whereas the other half was grown in soil close to field capacity. We conducted a pulse labelling with 13CO2 in the end of the study by injecting a known amount of 13C enriched CO2 to the seedlings and measuring the CO2 uptake and distribution of 13C to the biomass of the seedlings and to the root and rhizosphere respiration. In addition, we studied the effect of drought on the decomposition of needle litter and uptake of nitrogen by 15N labelled needles buried in the soil in litter bags. The litterbags were collected and harvested in the end of the experiment and the changes in microbial community in the litterbags were studied from the phospholipid fatty acid (PLFA) composition. We also determined the 15N isotope concentrations from the needles of the seedlings to study the effect of drought on the nitrogen uptake of the seedlings. Our results indicate that the drought had a significant effect both on the biomass allocation of the seedlings and on the microbial species composition. The amount of carbon allocated belowground was much higher in the seedlings exposed to drought compared to the control seedlings. The seedlings seemed to adapt their carbon allocation to long-term drought to sustain adequate needle biomass and water uptake. The seedlings also adapted their osmotic potential and photosynthesis capacity to sustain the long-term drought as was indicated by the measurements of osmotic potential

Radiation utilization efficiency, nitrogen uptake and modeling crop growth and yield of rainfed rice under different nitrogen rates

International Nuclear Information System (INIS)

Gouranga, Kar; Ashwani Kumar; Mohapatra, Sucharita

2014-01-01

Optimum utilization of photosynthetically active radiation (PAR) along with proper nitrogen (N) management for sustainable rice production is still a promising management recommendation for sustainable rainfed rice cultivation in eastern India. The objective of this investigation was to study radiation utilization efficiency (RUE), N uptake and modeling growth and productivity of wet/rainy season rice (cv. Lalat and Gayatri) under 0, 50, 90, 120 and 150 kg ha -1 N application. Results showed that N rates significantly affected plant biomass, leaf area index (LAI), biological yield (straw and grain yield) and N uptake for both the varieties. The intercepted photosynthetically active radiation (IPAR) and spectral reflectance based vegetation indices (IR/R, NDVI) were also different between two varieties and among N rates. Higher rate of N increased the RUE significantly; averaged over years and varieties, mean values of RUE were 1.35, 1.70, 2.01, 2.15 and 2.17 g MJ -1 under 0, 50, 90, 120 and 150 kg N ha -1 , respectively. Though crop growth, yield, N uptake and RUE were higher at 150 kg N ha -1 but the results were at par with 120 kg N ha -1 . Agronomic N use efficiency (ANUE) was also low at 150 kg N ha -1 . The DSSAT v 4.5 model was applied to simulate crop growth, yield and phenology of the crop under different N rates. Model performance was found to be poor at low N rates (0, 50 kg N ha -1 ), but the model performed fairly well at higher N rates (90 kg ha -1 and above). (author)

In situ bioremediation under high saline conditions

International Nuclear Information System (INIS)

Bosshard, B.; Raumin, J.; Saurohan, B.

1995-01-01

An in situ bioremediation treatability study is in progress at the Salton Sea Test Base (SSTB) under the NAVY CLEAN 2 contract. The site is located in the vicinity of the Salon Sea with expected groundwater saline levels of up to 50,000 ppm. The site is contaminated with diesel, gasoline and fuel oils. The treatability study is assessing the use of indigenous heterotrophic bacteria to remediate petroleum hydrocarbons. Low levels of significant macro nutrients indicate that nutrient addition of metabolic nitrogen and Orthophosphate are necessary to promote the process, requiring unique nutrient addition schemes. Groundwater major ion chemistry indicates that precipitation of calcium phosphorus compounds may be stimulated by air-sparging operations and nutrient addition, which has mandated the remedial system to include pneumatic fracturing as an option. This presentation is tailored at an introductory level to in situ bioremediation technologies, with some emphasize on innovations in sparge air delivery, dissolved oxygen uptake rates, nutrient delivery, and pneumatic fracturing that should keep the expert's interest

Grain quality and N uptake of spring cereals as affected by nitrogen fertilization in northern conditions: a meta-analysis

Directory of Open Access Journals (Sweden)

Elena Valkama

2013-06-01

Full Text Available We reviewed quantitatively 40 Finnish field experiments related to the effect of nitrogen (N fertilizer on the main parameters of grain quality and N uptake of spring cereals. The experiments were conducted on a wide range of mineral soils under varying growth conditions from the 1950s to the 1990s. Overall there was no statistically significant effect on 1000 grain weight and a slightly negative effect on grain test weight. Nitrogen fertilizer increased N uptake much more steeply in slightly acidic soils (SA, pH 5.8–6.9, located mostly in South Finland, than in moderately acidic soils (MA, pH 5.0–5.7, located in Central Finland. With increasing N rates, protein content increased to a larger extent in spring barley and oats than in spring wheat. In the light of the current trend to reduce N fertilizerapplication, the obtained regressions between N rates and the parameters of grain quality may be used to maintain yield quality at a desirable level, while optimizing N management.

Contribution of Nitrogen Uptake and Retranslocation during Reproductive Growth to the Nitrogen Efficiency of Winter Oilseed-Rape Cultivars (Brassica napus L. Differing in Leaf Senescence

Directory of Open Access Journals (Sweden)

Fabian Koeslin-Findeklee

2016-01-01

Full Text Available Genotypic variation in N efficiency defined as high grain yield under limited nitrogen (N supply of winter oilseed-rape line-cultivars has been predominantly attributed to N uptake efficiency (NUPT through maintained N uptake during reproductive growth related to functional stay-green. For investigating the role of stay-green, N retranslocation and N uptake during the reproductive phase for grain yield formation, two line cultivars differing in N starvation-induced leaf senescence were grown in a field experiment without mineral N (N0 and with 160 kg N·ha−1 (N160. Through frequent harvests from full flowering until maturity N uptake, N utilization and apparent N remobilization from vegetative plant parts to the pods could be calculated. NUPT proved being more important than N utilization efficiency (NUE for grain yield formation under N-limiting (N0 conditions. For cultivar differences in N efficiency, particularly N uptake during flowering (NUPT and biomass allocation efficiency (HI to the grains, were decisive. Both crop traits were related to delayed senescence of the older leaves. Remobilization of N particularly from stems and leaves was more important for pod N accumulation than N uptake after full flowering. Pod walls (high N concentrations and stems (high biomass mainly contributed to the crop-residue N at maturity. Decreasing the crop-inherent high N budget surplus of winter oilseed-rape requires increasing the low N remobilization efficiency particularly of pod-wall N to the grains. Addressing this conclusion, multi-year and -location field experiments with an extended range of cultivars including hybrids are desirable.

In situ self-sacrificed template synthesis of vanadium nitride/nitrogen-doped graphene nanocomposites for electrochemical capacitors.

Science.gov (United States)

Liu, Hong-Hui; Zhang, Hong-Ling; Xu, Hong-Bin; Lou, Tai-Ping; Sui, Zhi-Tong; Zhang, Yi

2018-03-15

Vanadium nitride and graphene have been widely used as pseudo-capacitive and electric double-layer capacitor electrode materials for electrochemical capacitors, respectively. However, the poor cycling stability of vanadium nitride and the low capacitance of graphene impeded their practical applications. Herein, we demonstrated an in situ self-sacrificed template method for the synthesis of vanadium nitride/nitrogen-doped graphene (VN/NGr) nanocomposites by the pyrolysis of a mixture of dicyandiamide, glucose, and NH 4 VO 3 . Vanadium nitride nanoparticles of the size in the range of 2 to 7 nm were uniformly embedded into the nitrogen-doped graphene skeleton. Furthermore, the VN/NGr nanocomposites with a high specific surface area and pore volume showed a high specific capacitance of 255 F g -1 at 10 mV s -1 , and an excellent cycling stability (94% capacitance retention after 2000 cycles). The excellent capacitive properties were ascribed to the excellent conductivity of nitrogen-doped graphene, high surface area, high pore volume, and the synergistic effect between vanadium nitride and nitrogen-doped graphene.

Precipitation reactions caused by nitrogen uptake during service at high temperatures of a niobium stabilised austenitic stainless steel

International Nuclear Information System (INIS)

Erneman, J.; Schwind, M.; Liu, P.; Nilsson, J.-O.; Andren, H.-O.; Aagren, J.

2004-01-01

Precipitation phenomena in type 347 austenitic stainless steels have been investigated after long-term heat treatment and creep in air at 700 and 800 deg. C. Nitrogen uptake was observed during long-term creep testing at 800 deg. C. No such effect was observed at 700 deg. C although times up to about 70,000 h were used. The major phases precipitated after long time exposure at 800 deg. C were primary Nb(C,N), Z-phase, Cr 2 N and M 23 C 6 , while primary Nb(C,N), secondary Nb(C,N) and σ-phase were the major phases at 700 deg. C. Z-phase precipitated in both intragranular and intergranular form at 800 deg. C. Large precipitates exhibiting a core/rim structure showed a rim of Z-phase surrounding undissolved primary Nb(C,N). The microstructural evolution during creep deformation in air at 800 deg. C was modelled thermodynamically. The model satisfactorily predicts nitrogen uptake and the essential features of the evolution of the microstructure with time. The precipitation sequence could be qualitatively described, although it was not possible to model the formation of all precipitates

Effect of organic manure on nitrogen mineralization, nitrogen accumulation, nitrogen use efficiency and apparent nitrogen recovery of cauliflower (Braccica oleracea L., var. Botrytis)

NARCIS (Netherlands)

Beah, A.A.; Norman, P.E.; Scholberg, J.M.S.; Lantinga, E.A.; Conteh, A.R.

2015-01-01

Aims: The main aim of the study was to assess the effects of organic manure on nitrogen mineralization, uptake, use and recovery of cauliflower.
Methodology: Nitrogen is one of the major yield limiting nutrients in cauliflower production. However, organic manure is applied to supplement soil

Using /sup 15/N in studies on the uptake of mineral and organic nitrogen by plants

Energy Technology Data Exchange (ETDEWEB)

Mitovska, R. (Akademiya na Selskostopanskite Nauki, Sofia (Bulgaria). Inst. po Pochvoznanie)

1983-01-01

Modelled microplot field experiments at the Central Experimental Station of the All-Union Institute of Fertilizers and Agrochemistry in Moscow were used to study the uptake of nitrogen (/sup 15/N) applied together or individually with minerals or with green oats mass or in both ways. The studies were conducted on soddy podzolic, heavy loam, soddy podzolic sandy soil and leached chernozem. It was established that the soddy podzolic heavy loam had the highest natural fertility and showed greatest response to the applied N.

Symbiotic nitrogen fixation and nitrate uptake by the pea crop

International Nuclear Information System (INIS)

Jensen, E.S.

1986-08-01

Symbiotic nitrogen fixation and nitrate uptake by pea plants (Pisum sativum L.) were studied in field and pot experiments using the 15 N isotope dilution technique and spring barley as a non-fixing reference crop. Barley, although not ideal, seemed to be a suitable reference for pea in the 15 N-technique. Maximum N 2 fixation activity of 10 kg N fixed per ha per day was reached around the flat pod growth stage, and the activity decreased rapidly during pod-filling. The pea crop fixed between 100 and 250 kg N ha -1 , corresponding to from 45 to 80 per cent of total crop N. The amount of symbiotically fixed N 2 depended on the climatic conditions in the experimental year, the level of soil mineral N and the pea cultivar. Field-grown pea took up 60 to 70 per cent of the N-fertilizer supplied. The supply of 50 kg NO 3 -N ha -1 inhibited the N 2 fixation approximately 15 per cent. Small amounts of fertilizer N, supplied at sowing (starter-N), slightly stimulated the vegetative growth of pea, but the yields of seed dry matter and protein were not significantly influenced. In the present field experiments the environmental conditions, especially the distribution of rainfall during the growth season, seemed to be more important in determining the protein and dry matter yield of the dry pea crop, than the ability of pea to fix nitrogen symbiotically. However, fertilizer N supplied to pot-grown pea plants at the flat pod growth stage or as split applications significantly increased the yield of seed dry matter and protein. (author)

Interaction of different irrigation strategies and soil textures on the nitrogen uptake of field grown potatoes

DEFF Research Database (Denmark)

Ahmadi, S.H.; Andersen, Mathias Neumann; Lærke, Poul Erik

2011-01-01

Nitrogen (N) uptake (kg ha-1) of field-grown potatoes was measured in 4.32 m2 lysimeters that were filled with coarse sand, loamy sand, and sandy loam and subjected to full (FI), deficit (DI), and partial root-zone drying (PRD) irrigation strategies. PRD and DI as water-saving irrigation treatments...... in the loamy sand had the highest amount of N uptake. The interaction between irrigation treatments and soil textures was significant, and implied that under non-limiting water conditions, loamy sand is the suitable soil for potato production because plants can take up sufficient amounts of N and it could...... potentially lead to higher yield. However, under limited water conditions and applying water-saving irrigation strategies, sandy loam and coarse sand are better growth media because N is more available for the potatoes. The simple yield prediction model was developed that could explains ca. 96...

Gaseous Nitrogen Losses from Tropical Savanna Soils of Northern Australia: Dynamics, Controls and Magnitude of N2O, NO, and N2 emissions

Science.gov (United States)

Werner, C.; Hickler, T.; Hutley, L. B.; Butterbach-Bahl, K.

2014-12-01

Tropical savanna covers a large fraction of the global land area and thus may have a substantial effect on the global soil-atmosphere exchange of nitrogen. The pronounced seasonality of hygric conditions in this ecosystem affects strongly microbial process rates in the soil. As these microbial processes control the uptake, production, and release of nitrogen compounds, it is thought that this seasonality finally leads to strong temporal dynamics and varying magnitudes of gaseous losses to the atmosphere. However, given their areal extent and in contrast to other ecosystems, still few in-situ or laboratory studies exist that assess the soil-atmosphere exchange of nitrogen. We present laboratory incubation results from intact soil cores obtained from a natural savanna site in Northern Australia, where N2O, NO, and N2 emissions under controlled environmental conditions were investigated. Furthermore, in-situ measurements of high temporal resolution at this site recorded with automated static and dynamic chamber systems are discussed (N2O, NO). This data is then used to assess the performance of a process-based biogeochemical model (LandscapeDNDC), and the potential magnitude and dynamics of components of the site-scale nitrogen cycle where no measurements exist (biological nitrogen fixation and nitrate leaching). Our incubation results show that severe nutrient limitation of the soil only allows for very low N2O emissions (0.12 kg N ha-1 yr-1) and even a periodic N2O uptake. Annual NO emissions were estimated at 0.68 kg N ha-1 yr-1, while the release of inert nitrogen (N2) was estimated at 6.75 kg N ha-1 yr-1 (data excl. contribution by pulse emissions). We observed only minor N2O pulse emissions after watering the soil cores and initial rain events of the dry to wet season transition in-situ, but short-lived NO pulse emissions were substantial. Interestingly, some cores exhibited a very different N2O emission potential, indicating a substantial spatial variability of

Nitrate signals determine the sensing of nitrogen through differential expression of genes involved in nitrogen uptake and assimilation in finger millet.

Science.gov (United States)

Gupta, Alok Kumar; Gaur, Vikram Singh; Gupta, Sanjay; Kumar, Anil

2013-06-01

In order to understand the molecular basis of high nitrogen use efficiency of finger millet, five genes (EcHNRT2, EcLNRT1, EcNADH-NR, EcGS, and EcFd-GOGAT) involved in nitrate uptake and assimilation were isolated using conserved primer approaches. Expression profiles of these five genes along with the previously isolated EcDof1 was studied under increased KNO3 concentrations (0.15 to 1,500 μM) for 2 h as well as at 1.5 μM for 24 h in the roots and shoots of 25 days old nitrogen deprived two contrasting finger millet genotypes (GE-3885 and GE-1437) differing in grain protein content (13.76 and 6.15 %, respectively). Time kinetics experiment revealed that, all the five genes except EcHNRT2 in the leaves of GE-3885 were induced within 30 min of nitrate exposure indicating that there might be a greater nitrogen deficit in leaves and therefore quick transportation of nitrate signals to the leaves. Exposing the plants to increasing nitrate concentrations for 2 h showed that in roots of GE-3885, NR was strongly induced while GS was repressed; however, the pattern was found to be reversed in leaves of GE-1437 indicating that in GE-3885, most of the nitrate might be reduced in the roots but assimilated in leaves and vice-versa. Furthermore, compared with the low-protein genotype, expression of HNRT2 was strongly induced in both roots and shoots of high-protein genotype at the least nitrate concentration supplied. This further indicates that GE-3885 is a quick sensor of nitrogen compared with the low-protein genotype. Furthermore, expression of EcDof1 was also found to overlap the expression of NR, GS, and GOGAT indicating that Dof1 probably regulates the expression of these genes under different conditions by sensing the nitrogen fluctuations around the root zone.

[Characteristics of dry matter production and nitrogen accumulation in barley genotypes with high nitrogen utilization efficiency].

Science.gov (United States)

Huang, Yi; Li, Ting-Xuan; Zhang, Xi-Zhou; Ji, Lin

2014-07-01

A pot experiment was conducted under low (125 mg x kg-1) and normal (250 mg x kg(-1)) nitrogen treatments. The nitrogen uptake and utilization efficiency of 22 barley cultivars were investigated, and the characteristics of dry matter production and nitrogen accumulation in barley were analyzed. The results showed that nitrogen uptake and utilization efficiency were different for barley under two nitrogen levels. The maximal values of grain yield, nitrogen utilization efficiency for grain and nitrogen harvest index were 2.87, 2.91 and 2.47 times as those of the lowest under the low nitrogen treatment. Grain yield and nitrogen utilization efficiency for grain and nitrogen harvest index of barley genotype with high nitrogen utilization efficiency were significantly greater than low nitrogen utilization efficiency, and the parameters of high nitrogen utilization efficiency genotype were 82.1%, 61.5% and 50.5% higher than low nitrogen utilization efficiency genotype under the low nitrogen treatment. Dry matter mass and nitrogen utilization of high nitrogen utilization efficiency was significantly higher than those of low nitrogen utilization efficiency. A peak of dry matter mass of high nitrogen utilization efficiency occurred during jointing to heading stage, while that of nitrogen accumulation appeared before jointing. Under the low nitrogen treatment, dry matter mass of DH61 and DH121+ was 34.4% and 38.3%, and nitrogen accumulation was 54. 8% and 58.0% higher than DH80, respectively. Dry matter mass and nitrogen accumulation seriously affected yield before jointing stage, and the contribution rates were 47.9% and 54.7% respectively under the low nitrogen treatment. The effect of dry matter and nitrogen accumulation on nitrogen utilization efficiency for grain was the largest during heading to mature stages, followed by sowing to jointing stages, with the contribution rate being 29.5% and 48.7%, 29.0% and 15.8%, respectively. In conclusion, barley genotype with high

Suppression of temperature instability in InGaZnO thin-film transistors by in situ nitrogen doping

International Nuclear Information System (INIS)

Raja, Jayapal; Jang, Kyungsoo; Yi, Junsin; Balaji, Nagarajan

2013-01-01

We have investigated the effect of nitrogen doping on the behavior of hysteresis curve and its suppression of temperature instability in amorphous InGaZnO thin-film transistors (a-IGZO TFTs). The in situ nitrogen doping reduced the temperature induced abnormal sub threshold leakage current and traps generation. Large falling-rate (F R ) ∼ 0.26 eV V −1 , low activation energy (E a ) ∼ 0.617 eV and a small hysteresis compared to the pure a-IGZO TFTs, shows the best immunity to thermal instability. This is mainly attributed to the reduction of interface trap density and oxygen vacancies due to the passivation of defects and/dangling bonds. (paper)

Use of the Stable Nitrogen Isotope to Reveal the Source-Sink Regulation of Nitrogen Uptake and Remobilization during Grain Filling Phase in Maize.

Directory of Open Access Journals (Sweden)

Lan Yang

Full Text Available Although the remobilization of vegetative nitrogen (N and post-silking N both contribute to grain N in maize (Zea mays L., their regulation by grain sink strength is poorly understood. Here we use 15N labeling to analyze the dynamic behaviors of both pre- and post-silking N in relation to source and sink manipulation in maize plants. The results showed that the remobilization of pre-silking N started immediately after silking and the remobilized pre-silking N had a greater contribution to grain N during early grain filling, with post-silking N importance increasing during the later filling stage. The amount of post-silking N uptake was largely driven by post-silking dry matter accumulation in both grain as well as vegetative organs. Prevention of pollination during silking had less effect on post-silking N uptake, as a consequence of compensatory growth of stems, husk + cob and roots. Also, leaves continuously export N even though grain sink was removed. The remobilization efficiency of N in the leaf and stem increased with increasing grain yield (hence N requirement. It is suggested that the remobilization of N in the leaf is controlled by sink strength but not the leaf per se. Enhancing post-silking N uptake rather than N remobilization is more likely to increase grain N accumulation.

Facile Synthesis of In–Situ Nitrogenated Graphene Decorated by Few–Layer MoS2 for Hydrogen Evolution Reaction

International Nuclear Information System (INIS)

Dai, Xiaoping; Li, Zhanzhao; Du, Kangli; Sun, Hui; Yang, Ying; Zhang, Xin; Ma, Xingyu; Wang, Jie

2015-01-01

Graphical abstract: In–situ nitrogenated graphene–few layer MoS 2 composites are fabricated by combinating chemical and hydrothermal reduction. The resulting MoS 2 /N–rGO–HA by N 2 H 4 ·H 2 O and NH 3 ·H 2 O as co-reductant exhibits high activity and remarkable stability for hydrogen evolution reaction (HER). The excellent electro-catalytic performance is ascribed to the synergistic effects, confinement effects and highly dispersed MoS 2 nanosheets on N-doping rGO. Display Omitted -- Highlights: • In–situ nitrogenated graphene–few layer MoS 2 composites are fabricated by combinating chemical and hydrothermal co-reduction. • The resulting MoS 2 /N–rGO–HA exhibits high activity and remarkable stability for HER. • The excellent electro-catalytic performance is ascribed to the synergistic effects, confinement effects and highly dispersed MoS 2 nanosheets on N-doping rGO. -- Abstract: A facile one–step synthetic strategy by combinating chemical and hydrothermal reduction of graphene oxide and Mo precursor is proposed to fabricate in–situ nitrogenated graphene–few layer MoS 2 composite (MoS 2 /N–rGO–HA) for hydrogen evolution reaction (HER). The N–doping graphene nanosheets and highly dispersed MoS 2 nanosheets by ammonia and hydrozine as co–reductant have greatly promoted the N content, concentrations of pyridinic and graphitic N, the electron transport in electrodes, and assure high catalytic efficiency. The MoS 2 /N–rGO–HA composite exhibits extremely high activity in acidic solutions with a small onset potential of 100 mV and Tafel slope of 45 mV/dec, as well as a current density about 32.4 mA cm −2 at overpotential about 0.2 V. Moreover, such MoS 2 /N–rGO–HA electroncatalyst also shows an excellent stability during 1000 cycles with negligible loss of the cathodic current. This facile hydrothermal method could provide a promising strategy for the synthesis of in–situ nitrogen–doping graphene sheets and few�

Ultraviolet electroluminescence from nitrogen-doped ZnO-based heterojuntion light-emitting diodes prepared by remote plasma in situ atomic layer-doping technique.

Science.gov (United States)

Chien, Jui-Fen; Liao, Hua-Yang; Yu, Sheng-Fu; Lin, Ray-Ming; Shiojiri, Makoto; Shyue, Jing-Jong; Chen, Miin-Jang

2013-01-23

Remote plasma in situ atomic layer doping technique was applied to prepare an n-type nitrogen-doped ZnO (n-ZnO:N) layer upon p-type magnesium-doped GaN (p-GaN:Mg) to fabricate the n-ZnO:N/p-GaN:Mg heterojuntion light-emitting diodes. The room-temperature electroluminescence exhibits a dominant ultraviolet peak at λ ≈ 370 nm from ZnO band-edge emission and suppressed luminescence from GaN, as a result of the decrease in electron concentration in ZnO and reduced electron injection from n-ZnO:N to p-GaN:Mg because of the nitrogen incorporation. The result indicates that the in situ atomic layer doping technique is an effective approach to tailoring the electrical properties of materials in device applications.

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

Science.gov (United States)

Xu, Zhiguang; Gao, Kunshan

2012-01-01

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. Copyright © 2011 Elsevier Ltd. All rights reserved.

Response of soil methane uptake to simulated nitrogen deposition and grazing management across three types of steppe in Inner Mongolia, China.

Science.gov (United States)

Li, Xianglan; He, Hong; Yuan, Wenping; Li, Linghao; Xu, Wenfang; Liu, Wei; Shi, Huiqiu; Hou, Longyu; Chen, Jiquan; Wang, Zhiping

2018-01-15

The response of soil methane (CH 4 ) uptake to increased nitrogen (N) deposition and grazing management was studied in three types of steppe (i.e., meadow steppe, typical steppe, and desert steppe) in Inner Mongolia, China. The experiment was designed with four simulated N deposition rates such as 0, 50, 100, and 200kgNha -1 , respectively, under grazed and fenced management treatments. Results showed that the investigated steppes were significant sinks for CH 4 , with an uptake flux of 1.12-3.36kgha -1 over the grass growing season and that the magnitude of CH 4 uptake significantly (Prates. The soil CH 4 uptake rates were highest in the desert steppe, moderate in the typical steppe, and lowest in the meadow steppe. Compared with grazed plots, fencing increased the CH 4 uptake by 4.7-40.2% with a mean value of 20.2% across the three different steppe types. The responses of soil CH 4 uptake to N deposition in the continental steppe varied depending on the N deposition rate, steppe type, and grazing management. A significantly positive correlation between CH 4 uptake and soil temperature was found in this study, whereas no significant relationship between soil moisture and CH 4 uptake occurred. Our results may contribute to the improvement of model parameterization for simulating biosphere-atmosphere CH 4 exchange processes and for evaluating the climate change feedback on CH 4 soil uptake. Copyright © 2017 Elsevier B.V. All rights reserved.

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

International Nuclear Information System (INIS)

Xu Zhiguang; Gao Kunshan

2012-01-01

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.

Nitrogen balance during growth of cauliflower

NARCIS (Netherlands)

Everaarts, A.P.

2000-01-01

The potential for loss of nitrogen to the environment during growth of cauliflower was investigated. A comparison was made between cauliflower growth and nitrogen uptake without, and with, nitrogen application of the recommended amount (=225 kg ha-1 minus mineral nitrogen in the soil layer 0–60 cm,

Modelling the ecosystem effects of nitrogen deposition: Model of Ecosystem Retention and Loss of Inorganic Nitrogen (MERLIN

Directory of Open Access Journals (Sweden)

B. J. Cosby

1997-01-01

Full Text Available 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

Nitrogen Uptake During Fall, Winter and Spring Differs Among Plant Functional Groups in a Subarctic Heath Ecosystem

DEFF Research Database (Denmark)

Larsen, Klaus Steenberg; Michelsen, Anders; Jonasson, Sven

2012-01-01

Nitrogen (N) is a critical resource for plant growth in tundra ecosystems, and species differences in the timing of N uptake may be an important feature regulating community composition and ecosystem productivity. We added 15N-labelled glycine to a subarctic heath tundra dominated by dwarf shrubs...... to 37 ± 7% by April indicating significant microbial N turnover prior to spring thaw. Only the evergreen dwarf shrubs showed active 15N acquisition before early May indicating that they had the highest potential of all functional groups for acquiring nutrients that became available in early spring....... The faster-growing deciduous shrubs did not resume 15N acquisition until after early May indicating that they relied more on nitrogen made available later during the spring/early summer. The graminoids and mosses had no significant increases in 15N tracer recovery or tissue 15N tracer concentrations after...

Comparison of nitrate accumulation, nitrogen uptake and utilization efficiency among different spinach (Spinacia oleracea L. genotypes

Directory of Open Access Journals (Sweden)

Zhou Jianjian

2017-10-01

Full Text Available A hydroponic experiment was conducted to study the difference of nitrate accumulation,nitrogen uptake and utilization efficiency between four spinach (Spinacia oleracea L. genotypes (So10,So13,So18 and So57. Results showed that So13 had the highest nitrate contents under two nitrate (NO3--N level (0.5 mmol·L-1,15 mmol·L-1 conditions,whereas So10 had the lowest nitrate contents. So18 had the similar nitrate contents with So13 under low NO3- level,while it showed no significant difference of nitrate contents with So57 under high NO3- treatment. The 15NO3--N uptake rates of So13 were the highest one among four genotypes,while the N utilization efficiency (NutE and N utilization ratio (NUR of So13 were significantly lower than those of So18 and So57. The shoot dry mass,nitrate reductase activity,NutE,NUR of So18 and So57 were higher than those of So13 and So10,while their 15NO3--N uptake rates were lower than those of So13. The shoot dry mass,nitrate reductase activity,NutE,N utilization ratio of So10 were significantly lower than those of So18 and So57,and its 15NO3--N uptake rate was significantly lower than those of So13. Among the four spinach genotypes,the So57 can be selected as elite germplasm using for spinach production for its relatively lower nitrate content and higher N efficiency.

Nitrogen Fertilizer and Straw Applications Affect Uptake of 13C,15N-Glycine by Soil Microorganisms in Wheat Growth Stages.

Directory of Open Access Journals (Sweden)

Lijie Yang

Full Text Available This study investigated the influence of nitrogen (N fertilizer and straw on intact amino acid N uptake by soil microorganisms and the relationship between amino acid turnover and soil properties during the wheat growing season. A wheat pot experiment was carried out with three treatments: control (CK, N fertilizer (NF and N fertilizer plus rice straw (NS. We used stable isotope compound-specific analysis to determine the uptake of 13C,15N-glycine by soil microorganisms. In the NF treatment, microbial 13C,15N-glycine uptake was lower compared with CK, suggesting that inorganic N was the preferred N source for soil microorganisms. However, The application of straw with N fertilizer (in NS treatment increased microbial 13C,15N-glycine uptake even with the same amount of N fertilizer application. In this treatment, enzyme activities, soil microbial biomass C and microbial biomass N increased simultaneously because more C was available. Soil mineral N and plant N contents all decreased substantially. The increased uptake of intact 13C,15N-glycine in the NS treatment can be attributed to direct assimilation by soil microorganisms to satisfy the demand for N when inorganic N was consumed.

Nitrogen incorporation and retention by bacteria, algae, and fauna in a subtropical, intertidal sediment: An in situ 15N-labeling study

NARCIS (Netherlands)

Veuger, B.; Eyre, B.D.; Maher, D.; Middelburg, J.J.

2007-01-01

We performed a 15N-labeling study to investigate nitrogen incorporation and retention by the benthic microbial community (bacteria and benthic microalgae) and fauna in the intertidal sediment of the subtropical Australian Brunswick Estuary. The main experiment involved an in situ 15N pulse–chase

Response of maize to reduced urea application combined with compound nitrogen fertilizer synergists

International Nuclear Information System (INIS)

Tian Xiuying; WANG Zhengyin

2006-01-01

Pot and field experiments were conducted to study the response to application rate of urea labeled with 15 N combined with compound nitrogen fertilizer synergists in the growth, yield, uptake and utilization rate of urea of maize. In pot experiment, the standard urea application rate is 120 mg/perpot; in field experiment, the standard urea application rate is 157.5 kg/hm 2 . Maize with 15 N-urea. The results showed that the growth of maize seedling was obviously promoted with appropriate dosage of compound nitrogen fertilizer synergists (20%-60% of N). The treatments of urea application rate reduced by 5%-15% and added compound nitrogen fertilizer synergists, the growth and nitrogen content of maize were not significant changed, and the total 15 N uptake and nitrogen uptake by maize were the same as CK 2 or increased a little. Nitrogen use efficiency of other treatments increased by 5.6%-7.3% comparing with CK, except the treatment of urea application rate reduced by 30%. The apparent utilization rate of nitrogen was enhanced by 7.7%-17.0%. Under the field condition, maize yield, total uptake, net uptake, physiological rate and agronomic use efficiency of nitrogen were the same as CK or increased. The apparent utilization rate of nitrogen was enhanced by 14.8%-15.2% treated with urea reduced by 5%-15% (7.8-23.7 kg/hm 2 ) and added with compound nitrogen fertilizer synergists. It was not helpful for the growth and nitrogen utilization rate of maize when urea reduced by 30% and combined with compound nitrogen fertilizer synergists. As a result, treated with urea decreased by 15% and combined with appropriate dosage of compound nitrogen fertilizer synergists (20% of urea), the growth and yield of maize had litter effect and higher the uptake and utilization of nitrogen. (authors)

Early sowing increases nitrogen uptake and yields of winter wheat grown with cattle slurry or mineral fertilizers

DEFF Research Database (Denmark)

Suarez, Alfonso; Rasmussen, Jim; Thomsen, Ingrid Kaag

2018-01-01

of the two cultivars did not differ consistently with respect to the effect of early sowing on crop yield, N concentration and offtake, or ANR. Within the north-west European climatic region, moving the sowing time of winter wheat from mid-September to mid-August provides a significant yield and N offtake......The current study evaluated the effect of sowing date (early, mid-August or timely, mid-September) on two winter wheat (Triticum aestivum L.) cultivars (Hereford, Mariboss) with different rates of nitrogen (N) (0–225 kg total N/ha) applied as animal manure (AM; cattle slurry) or mineral fertilizers...... (N: phosphorus: potassium; NPK). Overwinter plant N uptake and soil mineral N content were determined during 2014/15, while harvest yields (grain, straw, N content) were determined during 2014/15 and 2015/16. Overwinter uptake of N was 14 kg N/ha higher in early than in timely-sown wheat. Despite...

Nitrogen kinetics in aquatic plants in arctic Alaska

International Nuclear Information System (INIS)

McRoy, C.P.; Alexander, V.

1975-01-01

The kinetics of nitrogen in terms of ammonia uptake was measured for Carex aquatilis in arctic tundra ponds using 15 N tracer techniques. Nitrogen content of the leaves and primary productivity were measured throughout a growing season. The maximum uptake velocity for ammonia was 2.75 x 10 -2 % N/g dry weight per h with a Ksub(t) of 8.4-12.5 μgatoms/l. A second estimate of nitrogen uptake was made from the increase in nitrogen content throughout the season and from this a rate of 1.85 x 10 -2 % N/g dry weight per day was obtained for Carex aquatilis and 3.6 x 10 -2 % N/g dry weight per day for Arctophylla fulva. The total nitrogen concentration in the leaves was closely related to productivity, possible providing a new approach to productivity measurements for emergent vascular plants. Emergent vascular plants absorb ammonia across and translocate it to all portions of the plant. The ecological significance of this is considerable, since in many waters inorganic nitrogen content of sediment is much higher than that of the water surrounding the leaves and stems, and can provide a source of nitrogen

EFFECTS OF AMELIORANT COMPOSITIONS ON NITROGEN MINERALIZATION AND UPTAKE BY SWEET CORN IN DEGRADED PEATLAND

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Eni Maftu’ah

2014-04-01

Full Text Available Peat soil is characterized by poor nitrogen (N availability. Ameliorants are expected to rectify this problem. This research  aimed to study the effect of ameliorant on N availability and N uptake by sweet corn plant in degraded peatland. The experiment was conducted in the greenhouse in May-July 2011 and on peatland of Kalampangan Village, Palangkaraya, Central Kalimantan in September-December 2011. Burnt peat soil of Kalampangan was used in the greenhouse experiment and sweet corn was used as an indicator plant. The treatments consisted of two factors, i.e. compositions of ameliorants by weight (A1 = 80% chicken manure + 20% dolomite; A2 = 80% local farm weed + 20% dolomite; A3 = 80% mineral soil + 20% dolomite; A4 = 20% chicken manure + 20% local farm weed + 20% residue of Chinese water chestnut (Eleocharis dulcis + 20% mineral soil + 20% dolomite; and A5 = 19% chicken manure + 71.5% mineral soil + 9.5% dolomite and rates of those ameliorants (5, 10, 15, 20 and 25 t ha-1. The experiment was arranged in a completely randomized block design with three replications. Data were collected every two weeks for five times. Observations were made on soil pH, available N (NH4+, NO3-, plant height, and N uptake in root and shoot. The results showed that  treatment A1 increased soil pH and availability of NH4+ and NO3-  in peat soils at the maximum vegetative stage. Treatment A1 provided the highest N availability and N uptake by the plant. Field experiment showed that N uptake increased  with the plant yield. Optimum yield of fresh corn cob was obtained from treatment A1 at the rate of 20 t ha-1. This research reconfirms the effectiveness of chicken manure and dolomite as peat soil ameliorant.

Potential Pasture Nitrogen Concentrations and Uptake from Autumn or Spring Applied Cow Urine and DCD under Field Conditions

Science.gov (United States)

Moir, Jim; Cameron, Keith; Di, Hong

2016-01-01

Nitrogen (N) cycling and losses in grazed grassland are strongly driven by urine N deposition by grazing ruminants. The objective of this study was to quantify pasture N concentrations, yield and N uptake following autumn and spring deposition of cow urine and the effects of fine particle suspension (FPS) dicyandiamide (DCD). A field plot study was conducted on the Lincoln University dairy farm, Canterbury, New Zealand from May 2003 to May 2005. FPS DCD was applied to grazed pasture plots at 10 kg·ha−1 in autumn and spring in addition to applied cow urine at a N loading rate of 1000 kg·N·ha−1, with non-urine control plots. Pasture N ranged between 1.9 and 4.8% with higher concentrations from urine. Results indicated that urine consistently increased N concentrations for around 220 days post deposition (mid December/early summer) at which point concentrations dropped to background levels. In urine patches, pasture yield and annual N uptake were dramatically increased on average by 51% for autumn and 28% for spring applied urine, in both years, when DCD was applied. This field experiment provides strong evidence that annual pasture N uptake is more strongly influenced by high urine N deposition than pasture N concentrations. FPS DCD has the potential to result in very high N uptake in urine patches, even when they are autumn deposited. PMID:27304974

Nitrogen uptake and translocation by Chara

NARCIS (Netherlands)

Vermeer, C.P.; Escher, M.; Portielje, R.; Klein, de J.J.M.

2003-01-01

The potential for above-ground and below-ground uptake and subsequent internal translocation of ammonium (NH4+) and nitrate (NO3-) by the macroalga Chara spp. was investigated. In a two compartment experimental set-up separating above-ground and below-ground algal parts, the charophytes were exposed

Nitrogen and phosphorus uptake in two Idaho (USA) headwater wilderness streams.

Science.gov (United States)

Davis, Jeffrey C; Minshall, G Wayne

1999-05-01

Nitrate and phosphate solutions were released into two reaches of two central Idaho streams to determine within- and between-stream variability in uptake lengths, uptake rates, and mass transfer coefficients. Physical and biotic stream characteristics and periphyton nitrate-uptake rates in recirculating chambers were measured to determine their influence on nutrient dynamics. Phosphate uptake length did not differ among the four reaches. There were no within-stream differences in nitrate uptake lengths but they did differ between the two streams. Long nitrate uptake lengths likely were due to instream concentrations above saturation but also may have been influenced by differences in active surface area and algal abundance. Nitrate and phosphate uptake lengths were longer, and uptake rates higher, than most other published values. However, mass transfer coefficients were comparable to measurements in other streams. Mass transfer coefficients may be a better parameter for temporal and spatial comparisons of instream nutrient dynamics, and for determining the underlying causes of variability in uptake length.

Nitrogen uptake by phytoplankton in surface waters of the Indian sector of Southern Ocean during austral summer

Science.gov (United States)

Tripathy, S. C.; Patra, Sivaji; Vishnu Vardhan, K.; Sarkar, A.; Mishra, R. K.; Anilkumar, N.

2018-03-01

This study reports the nitrogen uptake rate (using 15N tracer) of phytoplankton in surface waters of different frontal zones in the Indian sector of the Southern Ocean (SO) during austral summer of 2013. The investigated area encompasses four major frontal systems, i.e., the subtropical front (STF), subantarctic front (SAF), polar front-1 (PF1) and polar front-2 (PF2). Southward decrease of surface water temperature was observed, whereas surface salinity did not show any significant trend. Nutrient (NO3 - and SiO4 4-) concentrations increased southward from STF to PF; while ammonium (NH4 +), nitrite (NO2 -) and phosphate (PO4 3-) remained comparatively stable. Analysis of nutrient ratios indicated potential N-limited conditions at the STF and SAF but no such scenario was observed for PF. In terms of phytoplankton biomass, PF1 was found to be the most productive followed by SAF, whereas PF2 was the least productive region. Nitrate uptake rate increased with increasing latitude, as no systematic spatial variation was discerned for NH4 + and urea (CO(NH2)2). Linear relationship between nitrate and total N-uptake reveals that the studied area is capable of exporting up to 60% of the total production to the deep ocean if the environmental settings are favorable. Like N-uptake rates the f-ratio also increased towards PF region indicating comparatively higher new production in the PF than in the subtropics. The moderately high average f-ratio (0.53) indicates potentially near equal contributions by new production and regenerated production to the total productivity in the study area. Elevation in N-uptake rates with declining temperature suggests that the SO with its vast quantity of cool water could play an important role in drawing down the atmospheric CO2 through the "solubility pump".

MACRO NUTRIENTS UPTAKE OF FORAGE GRASSES AT DIFFERENT SALINITY STRESSES

Directory of Open Access Journals (Sweden)

F. Kusmiyati

2014-10-01

Full Text Available The high concentration of sodium chloride (NaCl in saline soils has negative effects on the growth ofmost plants. The experiment was designed to evaluate macro nutrient uptake (Nitrogen, Phosphorus andPotassium of forage grasses at different NaCl concentrations in growth media. The experiment wasconducted in a greenhouse at Forage Crops Laboratory of Animal Agriculture Faculty, Diponegoro University.Split plot design was used to arrange the experiment. The main plot was forage grasses (Elephant grass(Pennisetum purpureum and King grass (Pennisetum hybrida. The sub plot was NaCl concentrationin growth media (0, 150, and 300 mM. The nitrogen (N, phosphorus (P and potassium (K uptake in shootand root of plant were measured. The result indicated increasing NaCl concentration in growth mediasignificantly decreased the N, P and K uptake in root and shoot of the elephant grass and king grass. Thepercentage reduction percentage of N, P and K uptake at 150 mM and 300 mM were high in elephant grassand king grass. It can be concluded that based on nitrogen, phosphorus and potassium uptake, elephantgrass and king grass are not tolerant to strong and very strong saline soil.

Forests, nitrogen and albedo, a very interesting trio indeed

Directory of Open Access Journals (Sweden)

Borghetti M

2009-01-01

Full Text Available A short comment is made on a recent paper (Ollinger et al. 2008 which shows that forest ecosystem carbon uptake in temperate and boreal forests is directly related to canopy nitrogen concentration and that both carbon uptake capacity and canopy nitrogen concentration are positively correlated with shortwave surface albedo measured with broad-band satellite sensors.

Identification of groundwater microorganisms capable of assimilating RDX-derived nitrogen during in-situ bioremediation

Energy Technology Data Exchange (ETDEWEB)

Cho, Kun-Ching [Zachry Department of Civil Engineering, Texas A& M University, College Station, TX 77843-3136 (United States); Fuller, Mark E.; Hatzinger, Paul B. [CB& I Federal Services, Lawrenceville, NJ 08648 (United States); Chu, Kung-Hui, E-mail: kchu@civil.tamu.edu [Zachry Department of Civil Engineering, Texas A& M University, College Station, TX 77843-3136 (United States)

2016-11-01

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), a nitroamine explosive, is commonly detected in groundwater at military testing and training sites. The objective of this study was to characterize the microbial community capable of using nitrogen derived from the RDX or RDX intermediates during in situ bioremediation. Active groundwater microorganisms capable of utilizing nitro-, ring- or fully-labeled {sup 15}N-RDX as a nitrogen source were identified using stable isotope probing (SIP) in groundwater microcosms prepared from two wells in an aquifer previously amended with cheese whey to promote RDX biodegradation. A total of fifteen 16S rRNA gene sequences, clustered in Clostridia, β-Proteobacteria, and Spirochaetes, were derived from the {sup 15}N-labeled DNA fractions, suggesting the presence of metabolically active bacteria capable of using RDX and/or RDX intermediates as a nitrogen source. None of the derived sequences matched RDX-degrading cultures commonly studied in the laboratory, but some of these genera have previously been linked to RDX degradation in site groundwater via {sup 13}C-SIP. When additional cheese whey was added to the groundwater samples, 28 sequences grouped into Bacteroidia, Bacilli, and α-, β-, and γ-Proteobacteria were identified. The data suggest that numerous bacteria are capable of incorporating N from ring- and nitro-groups in RDX during anaerobic bioremediation, and that some genera may be involved in both C and N incorporation from RDX. - Highlights: • Cheese whey addition resulted in 28 different clones associated with RDX degradation. • The 28 clones belong to Bacteroidia, Bacilli, and α-, β-, and γ-Proteobacteria. • SIP identified 15 clones using RDX and/or its metabolites as a nitrogen source. • The clones clustered in Clostridia, β-Proteobacteria, and Spirochaetes.

Identification of groundwater microorganisms capable of assimilating RDX-derived nitrogen during in-situ bioremediation

International Nuclear Information System (INIS)

Cho, Kun-Ching; Fuller, Mark E.; Hatzinger, Paul B.; Chu, Kung-Hui

2016-01-01

Hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), a nitroamine explosive, is commonly detected in groundwater at military testing and training sites. The objective of this study was to characterize the microbial community capable of using nitrogen derived from the RDX or RDX intermediates during in situ bioremediation. Active groundwater microorganisms capable of utilizing nitro-, ring- or fully-labeled "1"5N-RDX as a nitrogen source were identified using stable isotope probing (SIP) in groundwater microcosms prepared from two wells in an aquifer previously amended with cheese whey to promote RDX biodegradation. A total of fifteen 16S rRNA gene sequences, clustered in Clostridia, β-Proteobacteria, and Spirochaetes, were derived from the "1"5N-labeled DNA fractions, suggesting the presence of metabolically active bacteria capable of using RDX and/or RDX intermediates as a nitrogen source. None of the derived sequences matched RDX-degrading cultures commonly studied in the laboratory, but some of these genera have previously been linked to RDX degradation in site groundwater via "1"3C-SIP. When additional cheese whey was added to the groundwater samples, 28 sequences grouped into Bacteroidia, Bacilli, and α-, β-, and γ-Proteobacteria were identified. The data suggest that numerous bacteria are capable of incorporating N from ring- and nitro-groups in RDX during anaerobic bioremediation, and that some genera may be involved in both C and N incorporation from RDX. - Highlights: • Cheese whey addition resulted in 28 different clones associated with RDX degradation. • The 28 clones belong to Bacteroidia, Bacilli, and α-, β-, and γ-Proteobacteria. • SIP identified 15 clones using RDX and/or its metabolites as a nitrogen source. • The clones clustered in Clostridia, β-Proteobacteria, and Spirochaetes

Utilization of inorganic and organic nitrogen by bacteria in marine systems

International Nuclear Information System (INIS)

Wheeler, P.A.; Kirchman, D.L.

1986-01-01

The relative contribution of various inorganic and organic forms of nitrogen to the nitrogen requirements of picoplankton was examined with 15 N tracers. Size fractionation was used to measure uptake by <1-μm size microorganisms, and inhibitors of protein synthesis were used to separate procaryotic from eucaryotic nitrogen uptake. Picoplankton utilized mainly ammonium and amino acids and only negligible amounts of nitrate and urea. Nearly all amino acid uptake was by procaryotes, while both procaryotes and eucaryotes utilized ammonium. About 78% of total ammonium uptake was by procaryotes, and a significant portion of this was due specifically to heterotrophic bacteria. Regeneration of ammonium was correlated with eucaryotic rather than procaryotic activity. Ammonium accounted for at least 20-60% of the summed ammonium plus amino acid utilization by bacteria. The results suggest that significant portion of ammonium uptake in the euphotic zone was by heterotrophic bacteria rather than solely by phytoplankton. This may invalidate the use of the Redfield C:N ratio for estimating rates of nitrogen assimilation in the euphotic zone from carbon assimilation rates

Nitrogen nutrition of Canna indica: Effects of ammonium versus nitrate on growth, biomass allocation, photosynthesis, nitrate reductase activity and N uptake rates

DEFF Research Database (Denmark)

Konnerup, Dennis; Brix, Hans

2010-01-01

The effects of inorganic nitrogen (N) source (NH4+, NO3- or both) on growth, biomass allocation, photosynthesis, N uptake rate, nitrate reductase activity and mineral composition of Canna indica were studied in hydroponic culture. The relative growth rates (0.05-0.06 g g-1 d-1), biomass allocation...

Metatranscriptomics reveal differences in in situ energy and nitrogen metabolism among hydrothermal vent snail symbionts.

Science.gov (United States)

Sanders, J G; Beinart, R A; Stewart, F J; Delong, E F; Girguis, P R

2013-08-01

Despite the ubiquity of chemoautotrophic symbioses at hydrothermal vents, our understanding of the influence of environmental chemistry on symbiont metabolism is limited. Transcriptomic analyses are useful for linking physiological poise to environmental conditions, but recovering samples from the deep sea is challenging, as the long recovery times can change expression profiles before preservation. Here, we present a novel, in situ RNA sampling and preservation device, which we used to compare the symbiont metatranscriptomes associated with Alviniconcha, a genus of vent snail, in which specific host-symbiont combinations are predictably distributed across a regional geochemical gradient. Metatranscriptomes of these symbionts reveal key differences in energy and nitrogen metabolism relating to both environmental chemistry (that is, the relative expression of genes) and symbiont phylogeny (that is, the specific pathways employed). Unexpectedly, dramatic differences in expression of transposases and flagellar genes suggest that different symbiont types may also have distinct life histories. These data further our understanding of these symbionts' metabolic capabilities and their expression in situ, and suggest an important role for symbionts in mediating their hosts' interaction with regional-scale differences in geochemistry.

Nitrogenous fertilizer uptake by guinea grass in several growth flushes

International Nuclear Information System (INIS)

Ambrosano, E.J.; Ambrosano, G.M.B.

1996-01-01

Nitrogen recovery was evaluated by the 15 N absorption by guineagrass cv. Tobiata. 15 N fertilizer was applied in February, March, May, June, August and September, in posts containing 5 kg of limed and fertilized soil, under greenhouse conditions in Piracicaba, State of Sao Paulo, Brazil. For each 15 N application three cuttings were performed at approximately 5-7 week interval. The following measurements were taken: consumed water, dry matter yield, nitrogen content, nitrogen in the plant derived form the fertilizers (Ndff), nitrogen recovery (R), and the relation between dry matter yield and nitrogen content. It was also determined the number of vegetative and reproductive tillers and apical meristem elimination. Plant growth was reduced after flowing; highest values of nitrogen recovery in the three cutting were observed for 15 N-fertilizer applied in September and August; highest residual effects, in the second and third cuttings after fertilizers 15 N applications, were observed in September, June and August, reaching 22% in September. (author)

Traits affecting early season nitrogen uptake in nine legume species

Directory of Open Access Journals (Sweden)

Elana Dayoub

2017-02-01

Full Text Available Legume crops are known to have low soil N uptake early in their life cycle, which can weaken their ability to compete with other species, such as weeds or other crops in intercropping systems. However, there is limited knowledge on the main traits involved in soil N uptake during early growth and for a range of species. The objective of this research was to identify the main traits explaining the variability among legume species in soil N uptake and to study the effect of the soil mineral N supply on the legume strategy for the use of available N sources during early growth. Nine legume species were grown in rhizotrons with or without N supply. Root expansion, shoot and root biomass, nodule establishment, N2 fixation and mineral soil N uptake were measured. A large interspecific variability was observed for all traits affecting soil N uptake. Root lateral expansion and early biomass in relation to seed mass were the major traits influencing soil N uptake regardless of the level of soil N availability. Fenugreek, lentil, alfalfa, and common vetch could be considered weak competitors for soil N due to their low plant biomass and low lateral root expansion. Conversely, peanut, pea, chickpea and soybean had a greater soil N uptake. Faba bean was separated from other species having a higher nodule biomass, a higher N2 fixation and a lower seed reserve depletion. Faba bean was able to simultaneously fix N2 and take up soil N. This work has identified traits of seed mass, shoot and root biomass, root lateral expansion, N2 fixation and seed reserve depletion that allowing classification of legume species regarding their soil N uptake ability during early growth.

Use of stable nitrogen isotope 15N in investigating nitrogen uptake by plants from allylisothiocyanate decomposition products

International Nuclear Information System (INIS)

Dolejskova, J.; Kovar, J.

1976-01-01

The assimilability of nitrogen from allylisothiocyanate or from its nitrogenous decomposition products by plants was investigated using 15 N-labelled allylisothiocyanate. The results show that plant nitrogen assimilation from allylisothiocyanate is the higher, the lower the total nitrogen content of the nutritive medium. (author)

f-Ratios calculated with and without urea uptake in nitrogen uptake by phytoplankton

Digital Repository Service at National Institute of Oceanography (India)

Wafar, M.V.M.; Corre, P.L.; L'Helguen, S.

. Peterson (1979) Particulate organic matter Hux and planktonic new production in the deep ocean. Nature, 282,677-6X0. Epplcy R. W., .I. H. Sharp, E. H. Renger, M. J. Perry and W. G. Harrison (1977) Nitrogen assimilation by phytoplankton and other... f’rogress Serres. 67, 275-2X3. Harrison W. G.. I_. R. Harris, D. M. Karl. G. A. Knauer and D. G. Redaljc (1992) Nitrogen dynamics at the Vcrtcx time-series site. DeepSea Revearch. 39, 1.535-1557. Harvey W. A. and J. Caperon (1976) The rate...

Growth, Carbon Isotope Discrimination and Nitrogen Uptake in Silicon and/or Potassium Fed barley Grown under Two Watering Regimes

OpenAIRE

Kurdali, Fawaz; Al-Chammaa, Mohammad

2013-01-01

The present pot experiment was an attempt to monitor the beneficial effects of silicon (Si) and/or potassium (K) applications on growth and nitrogen uptake in barley plants grown under water (FC1) and non water (FC2) stress conditions using 15N and 13C isotopes. Three fertilizer rates of Si (Si 50, Si 100 and Si 200) and one fertilizer rate of K were used. Dry matter (DM) and N yield (NY) in different plant parts of barley plants was affected by Si and/ or K fertilization as well as by the wa...

Anthropogenic nitrogen input traced by means of δ 15N values in macroalgae: Results from in-situ incubation experiments

International Nuclear Information System (INIS)

Deutsch, Barbara; Voss, Maren

2006-01-01

The macroalgae species Fucus vesiculosus (Phaeophyta), Polysiphonia sp., and Ceramium rubrum (Rhodophyta) originally grown at an unpolluted brackish site of the southern Baltic Sea were incubated for 10 and 14 days at 12 stations along a salinity gradient in a highly polluted estuary. We have expected an adaptation of the initially low δ 15 N values to the higher ones within the incubation period. In addition to the macroalgae the δ 15 N values of NO 3 - were measured to evaluate fractionation processes of the source nitrate. Inside the estuary, δ 15 N-NO 3 - values were 6.2-9.7 per mille , indicating anthropogenic nitrogen sources. The red macroalgae adequately reflected the nitrate isotope values in the surrounding waters, whereas for F. vesiculosus the results were not that clear. The reasons were assumed to be higher initial δ 15 N values of F. vesiculosus and presumably a too slow nitrogen uptake and growth rate. The method of macroalgae incubations seems suitable as a simple monitoring to study the influence of anthropogenic nitrogen loading in an estuarine environment

Seasonal changes in nitrogen availability, and root and microbial uptake of ¹⁵N¹³C₉-phenylalanine and ¹⁵N-ammonium in situ at a temperate heath

DEFF Research Database (Denmark)

Andresen, Louise C.; Michelsen, Anders; Jonasson, Sven Evert

2011-01-01

In the plant biosynthesis of secondary compounds, phenylalanine is a precursor of condensed tannins. Tannins are deposited into the soil in plant root exudates and dead plant material and have been suggested to precipitate some soil nutrients and hence reduce nutrient availability for plants. Free...... amino acid,inorganic and microbial N concentration during the growing season was investigated in an ecosystem with a natural tannin chemosphere. The influence of tannins on the uptake of nitrogen in plants and microbes was followed by injecting tannic acid (TA), ammonium-15N and phenylalanine-15N/13C9...

Nitrogen nutrition of the grape-vine (Vitis vinifera spp)

International Nuclear Information System (INIS)

Conradie, W.J.

1985-12-01

A thorough knowledge concerning the nitrogen relationship in the grape-vine is essential in order to appreciate how different patterns of uptake, assimilation, storage and utilisation of nitrogen might be advantageous in particular environmental situations. The 15 N-isotope technique has been used to determine the uptake and distribution of nitrogen absorbed during early spring, early summer and autumn. Apart from the total N fraction, protein N and soluble N were determined as well. The utilisation of labelled N applied in the field, was determined for vineyards on heavier and lighter soils

Incorporation of low energy activated nitrogen onto HOPG surface: Chemical states and thermal stability studies by in-situ XPS and Raman spectroscopy

Science.gov (United States)

Chandran, Maneesh; Shasha, Michal; Michaelson, Shaul; Hoffman, Alon

2016-09-01

In this paper we report the chemical states analysis of activated nitrogen incorporated highly oriented pyrolytic graphite (HOPG) surface under well-controlled conditions. Nitrogen incorporation is carried out by two different processes: an indirect RF nitrogen plasma and low energy (1 keV) N2+ implantation. Bonding configuration, concentration and thermal stability of the incorporated nitrogen species by aforesaid processes are systematically compared by in-situ X-ray photoelectron spectroscopy (XPS). Relatively large concentration of nitrogen is incorporated onto RF nitride HOPG surface (16.2 at.%), compared to N2+ implanted HOPG surface (7.7 at.%). The evolution of N 1s components (N1, N2, N3) with annealing temperature is comprehensively discussed, which indicates that the formation and reorganization of local chemical bonding states are determined by the process of nitridation and not by the prior chemical conditioning (i.e., amorphization or hydrogenation) of the HOPG surface. A combined XPS and Raman spectroscopy studies revealed that N2+ implantation process resulted in a high level of defects to the HOPG surface, which cannot be annealed-out by heat treatment up to 1000 °C. On the other hand, the RF nitrogen plasma process did not produce a high level of surface defects, while incorporating nearly the same amount of stable nitrogen species.

Nitrogen cycling in Hot Spring Sediments and Biofilms (Invited)

Science.gov (United States)

Meyer-Dombard, D. R.; Burton, M. S.; Havig, J. R.; Shock, E.

2010-12-01

capacity for nitrogen fixation as a function of changing community structure become apparent. Our results provide insight into shifts in genomic and transcriptomic function in the context of niches within hot spring environments, and the effect of availability of fixed nitrogen on the growth habit of microbial communities in situ in these ecosystems. [1] Havig et al., 2010. Merging isotopes and community genomics in a siliceous sinter-depositing hot spring. Journal of Geophysical Research-Biogeosciences (in press). [2] Raymond et al., 2008. EOS Trans AGU. Abstract B14A-03. [3] Hall et al., 2008. Molecular characterization of the diversity and distribution of a thermal spring microbial community using rRNA and metabolic genes. AEM 74:4910-4922. [4] Steunou et al., 2006. In situ analysis of nitrogen fixation and metabolic switching in unicellular thermophilic Cyanobacteria inhabiting hot spring microbial mats. PNAS 103:2398-2403. [5] Boyd et al., 2009. CO2 uptake and fixation by a thermoacidophilic microbial community attached to precipitated sulfur in a geothermal spring. AEM 75:4289-4296.

Environmental factors affecting rates of nitrogen cycling

International Nuclear Information System (INIS)

Lipschultz, F.

1984-01-01

The nitrogen cycle in the eutrophic Delaware river was studied in late summer, 1983 using 15 N tracer additions of NHG 4 + , NO 2 - , and NO 3 - . Rates for nine different transformations were calculated simultaneously with a least-squares minimization analysis. Light was found to stimulate ammonium uptake and to inhibit ammonium oxidation. Rates for nitrification, ammonium uptake by phytoplankton, and photosynthesis were integrated over 24 hours and river depth. High turbidity lifted the effect of light inhibition on nitrification and restricted phytoplankton uptake. Uptake of ammonium contributed over 95% of the inorganic nitrogen ration for phytoplankton, with dark uptake accounting for more than 50%. A mass-conservation, box model of river was used to calculate rate constants required to reproduce observed nutrient concentration changes. The calculated constants correlated well with the measured 15 N and oxygen integrated rates. Water-column nitrification was the major loss term for NH 4 + , while water column regeneration was the primary source. Loss of oxidized nitrogen was insignificant. Oxygen consumption and air-water exchange far exceeded net photosynthetic oxygen production. Nitrification contributed less than 1% to the oxygen demand near Philadelphia but up to 25% further downstream. Production of NO and N 2 O was measured under varying oxygen concentrations in batch cultures of the nitrifying bacteria Nitrosomonas europaea and Nitrosococcus oceanus. Production of both gases increased relative to nitrite production as oxygen levels decreased

Effect of coated urea and non-coated urea on grain yield, N uptake and N distribution in different parts of maize

International Nuclear Information System (INIS)

Ren Yi; Li Guihua; Zhao Linping; Zhang Shuxiang

2011-01-01

In order to regulate nitrogen metabolism with nitrogen application rate and to increase nitrogen use efficiency, an isotopic method was used to compare grain yield, biomass and nitrogen use efficiency of coated urea (CU) to those of non-coated urea (U) at the N application rates of 0, 100, 150 and 225 kg/hm 2 . Results showed that CU significantly increased maize N uptake from 15 N fertilizer and aboveground biomass. The nitrogen use efficiency ( 15 NUE) of CU was 13.3-21.4% greater than that of U. There was a significant different of fertilizer 15 N uptake between CU and U in maize parts. And N uptake of CU treatment followed the order of seed > leaves > straws > cob > husk, while N uptake of U treatment was in the order of seed > straws > leaves > cob > husk. The N uptake of maize parts by both CU and U followed the same order when non-isotopic method was applied. No significant variations were observed among treatments in N uptake, Nitrogen Harvest Index and grain yield. The reason maybe that low soil temperatures (< 10 ℃) from the fourth week of October to next April reduced N uptake of winter wheat, therefore, residual NO3-N in cultivated soil layer was high after harvest. Thus, maize N uptake was more dependent on the shoot growth potential than fertilizer amount and types under high amount of available nitrogen. (authors)

Bacterial uptake of photosynthetic carbon from freshwater phytoplankton

International Nuclear Information System (INIS)

Coveney, M.F.

1982-01-01

Microheterotrophic uptake of algal extracellular products was studied in two eutrophic lakes in southern Sweden. Size fractionation was used in H 14 CO 3 uptake experiments to measure 14 C fixation in total particulate, small particulate and dissolved organic fractions. Carbon fixed in algal photosynthesis was recovered as dissolved and small particulate 14 C, representing excretion and bacterial uptake of algal products. Estimated gross extracellular release was low in these eutrophic systems, 1 to 7% of total 14 C uptake per m 2 lake surface. From 28 to 80 % of 14 C released was recovered in the small particulate fraction after ca. 4h incubation.This percentage was uniform within each depth profile, but varied directly with in situ water temperature. Laboratory time-series incubations indicated steady state for the pool of algal extracellular products on one occasion, while increasing pool size was indicated in the remaining two experiments. Uptake of photosynthetic carbon to small particles in situ was 32 to 95% of estimted heterotrophic bacterial production (as dark 14 CO 2 uptake) on four occasions. While excretion apparently was not an important loss of cabon for phytoplankton, it may have represented an important carbon source for planktonic bacteria. (author)

Effect of different nitrogen application types on nitrogen utilization efficiency and fate of fertilizer for sugacane

International Nuclear Information System (INIS)

Wei Jianfeng; Wei Dongping; Liu Huanyu; Chen Chaojun; Lan Libin; Liang He

2013-01-01

A pot experiment in greenhouse was conducted with "1"5N-labeled urea 5 g/pot (equal to 450 kg · hm"-"2) total nitrogen by three kinds of treatments of disposable bottom application nitrogen before sowing (T1), 50% nitrogen before sowing and 50% nitrogrn during tillering stage (T2), and 30% nitrogen before sowing, 30% nitrogen during tillering stage and 40% nitrogen applied during elongation stage (T3) to investigate the use efficiency and fate of fertilizer nitrogen using the sugarcane cultivar ROC22. Results showed that almost 18% ∼ 29% of total N uptake by sugarcane was supplied by fertilizer, and 71% ∼ 82% N derived from soil and seed-stem. Nitrogen use efficiency ranged from 21.0% to 34.52%, with "1"5N-fertilizer residue of 37.61% ∼ 44.13%, and "1"5N-fertilizer loss of 21.35% ∼ 41.39% among three treatments. Under the three levels of nitrogen application, residual was "1"5N-fertilizer was mainly distributed in 0 ∼ 20 cm top soil. The uptake of nitrogen and the proportion of total N from fertilizer in sugarcane plant, the yield of stalk and sugar after the nitrogen applied, and the use efficiency and residue ratio of "1"5N-fertilizer increased significantly over time, while loss rate of "1"5N-fertilizer decreased significantly with a slight decline trend of nitrogen distribution and sucrose accumulation in stalk. The results also indicated that after the nitrogen applied the amounts "1"5N-fertilizer residue in 0 ∼ 20 cm top soil showed a rising trend, but dropped in 20 ∼ 40 cm soil profile. From the viewpoints of economic benefit and ecological benefit, the nitrogen fertilizer applied of T3 could be optimal treatment. (authors)

Nitrogen utilization during spring phytoplankton bloom development in the southeast Bering Sea

International Nuclear Information System (INIS)

Sambrotto, R.N.

1983-01-01

Interactions beween a high latitude, continental shelf, spring phytoplankton bloom and water column physics and chemistry were studied using 15 N measured rates of nitrogen uptake. Peak bloom conditions commenced when the mixed layer shallowed and minimized respirational losses. Integrative light-mixing growth models were accurate during early bloom stages. An advection-diffusion model associated peak bloom nitrate uptake with pycnocline mixing rates of 2.1 m d -1 in an 18 m mixed layer. Maximum nitrogen specific uptake rates (hr -1 ), unlike those of carbon, coincided with peak bloom conditions. Although species compositions among peak bloom periods were similar, particulate C/N ratios were not. Apparently, both intercellular factors and prevailing mixing conditions influence specific uptake rates and cell composition. A large proportion of new (nitrate) to total productivity was associated with the dominance of the early bloom forming diatoms in the mixed layer. In the absence of these net plankton the residual nanoplankton dominated community exhibited a greater dependence on regenerated nitrogen. Nitrate uptake averaged 700 mg-at m -2 during the spring bloom and 1 g-at m -2 year -1 . The yearly f factor was 0.40. Nitrogen uptake based carbon productivity was 188 g C m -2 year -1

The effects of soil water conditions on nitrogen fertilization use efficiency

International Nuclear Information System (INIS)

Zhou Lingyun

1996-01-01

Concerning with applied nitrogen fertilizer, the uptake as well as loss of nitrogen is mainly related to soil water content. The effects of soil water condition in wheat field on the uptake, leach and loss of nitrogen fertilizer were studied using 15 N tracing technique. The results showed that within certain range of soil water supply, from 180 to 360 mm of available water storage, the loss of nitrogen was in direct proportion to the amount of fertilizer application and the nitrogen use efficiency decreased with the increase of nitrogen application. In other words, the nitrogen use efficiency descended with the nitrogen application increased in an order of 75 kgN/ha, 150 kgN/ha, 225 kgN/ha. One interesting result was that the nitrogen use efficiencies ranged from 17.0% to 30.5% for the treatments receiving the same application rate of 75 kgN/ha

Effects of potassium application on the accumulated nitrogen source and yield of peanut

International Nuclear Information System (INIS)

Wang Yuefu; Kang Yujie; Wang Minglun; Zhao Changxing

2013-01-01

Pot experiments and were carried out respectively to study the effects of different potassium application on soil nitrogen uptake, fertilizer nitrogen uptake, nodule nitrogen fixation and their proportion and yield of peanut (Arachis Hypogaea L.) by "1"5N tracer technique, and explore the reasons, which may provide a theoretical basis and technical guidance for peanut production in the scientific fertilizer application. Results showed that nitrogen in peanut all mainly accumulated in the kernel for different treatments of potassium fertilizer application. However, with increasing of potassium application, the increasing extent of nitrogen content of stems was the biggest during all the peanut organs, with nut shells the smallest. Properly increasing the amount of potassium can improve nitrogen content, "1"5N abundance, nitrogen and "1"5N accumulation of every organ, and promote absorption and utilization three nitrogen-source especially with the most effect for the kernel biomass (economic output). The ratio of fertilizer nitrogen, soil nitrogen and atmospheric nitrogen absorbed by peanut was respectively between 12.37%-13.10%, 38.29%-45.10%, and 42.53%-48.31% respectively. Properly increasing potassium fertilizer application improved the absorption ratio of fertilizer nitrogen and nodule nitrogen fixation, reduced the proportion of soil uptake and enhanced fertilizer nitrogen use efficiency. However, the influences of excessive application of potassium fertilizer decreased. (authors)

Evaluation of Nitrogen Uptake and Growth Performance of Advanced Mutant Lines MR219-4 and MR219-9 Grown Under Aerobic Conditions

International Nuclear Information System (INIS)

Shyful Azizi Abdul Rahman; Abdul Rahim Harun; Rusli Ibrahim; Khairuddin Abdul Rahim

2014-01-01

Developing a good crop production management package; drought resistance variety, effective water and nutrient management in rice production practices is crucial for global climate change adaptation. A research project under IAEA RAS5065 (Supporting Climate-Proofing Rice Production Systems (CRiPS) Based on Nuclear Applications) was conducted from 2012 to 2013, in collaboration with MARDI. Two advanced mutant lines, MR219-4 and MR219-9 were used in this research project to evaluate growth, yield potential and fertilizer uptake under different water input condition (flooded and aerobic). The advanced mutant line MR219-9 showed comparable growth, yield and nitrogen uptake under both flooded and aerobic conditions. The yield and yield components are not significantly different from the parent variety (MR219) but total N uptake was lower than MR219 regardless of water regime. The field trial showed that MR219-9 has a better total N content which is comparable to the aerobic rice variety (MRIA 1) and this indicates that this advance mutant line MR219-9 is a potential aerobic rice variety. (author)

Continuous ammonium enrichment of a woodland stream: uptake kinetics, leaf decomposition, and nitrification

Energy Technology Data Exchange (ETDEWEB)

Newbold, J D; Elwood, J W; Schulze, M S; Stark, R W; Barmeier, J C

1983-01-01

In order to test for nitrogen limitation and examine ammonium uptake by stream sediments, ammonium hydroxide was added continuously at concentrations averaging 100 /sup +/gl/sup -1/ for 70 days to a second-order reach of Walker Branch, an undisturbed woodland stream in Tennessee. Ammonium uptake during the first 4 h of addition corresponded to adsorption kinetics rather than to first-order uptake or to Michaelis-Menten kinetics. However, the calculated adsorption partition coefficient was two to four orders of magnitude greater than values reported for physical adsorption of ammonium, suggesting that the uptake was largely biotic. Mass balance indicated that the uptake of ammonium from the water could be accounted for by increased nitrogen content in benthic organic detritus. Nitrification, inferred from longitudinal gradients in NO/sub 3/, began soon after enrichment and increased dramatically near the end of the experiment. Both ammonium and nitrate concentrations dropped quickly to near background levels when input ceased, indicating little desorption or nitrification of excess nitrogen stored in the reach. There was no evidence of nitrogen limitation as measured by weight loss, oxygen consumption, phosphorus content, and macroinvertebrate density of red oak leaf packs, or by chlorophyll content and aufwuchs biomass on plexiglass slides. A continuous phosphorus enrichment 1 year earlier had demonstrated phosphorus limitation in Walker Branch. 38 references, 6 figures, 3 tables.

Studies of the efficiency of nitrogen placement methods and slow release nitrogen fertilizers for rice and wheat, using N-15 labelled fertilizers

International Nuclear Information System (INIS)

Shaukat, A.

1979-12-01

A series of experiments with rice and wheat were carried out to study the efficiency of nitrogen placement methods and slow-release nitrogen fertilizers for these two crops using N-15-labelled fertilizer. The results show that (1) reduced N levels, of the order of 75 percent of the full recommended dose, are equally efficient as the full dose for wheat. The yield of rice grain increased with the increased dose of nitrogen; (2) Point placement of fertilizers for rice was superior to broadcast application in terms of uptake and yield. For optimum yield of wheat grain, urea should perferably be applied as a single dose banded between the rows at 5 cm depth or by broadcasting and incorporation in the soil at the time of sowing; (3) Sulphur-coated urea (SCU) at a comparable dose and mode of application gave better yields of rice grain than the application of urea and IBDU (Isobutylidine Diurea); (4) More nitrogen was taken up by wheat when SCU was applied. The best uptake was when it was applied half at sowing and half at tillering. The nitrogen uptake from the SCU by point placement was better for rice plants than broadcast application and was higher in magnitude than the IBDU

Dry matter yield, carbon isotope discrimination and nitrogen uptake in silicon and/ or potassium fed chickpea and barley plants grown under water and non-water stress conditions

International Nuclear Information System (INIS)

Kurd Ali, F.; Al-Chammaa, M.; Mouasess, A.

2012-09-01

A pot experiment was conducted to study the effects of silicon (Si) and/or potassium (K) on dry matter yield, nitrogen uptake and carbon isotope discrimination Δ 13 C in water stressed (FC1) and well watered (FC2) chickpea plants using 15 N and 13 C isotopes. Three fertilizer rates of Si (Si 5 0, Si 1 00 and Si 2 00) and one fertilizer rate of K were used. The results showed that: In chickpeas, it was found, for most of the growth parameters, that Si either alone or in combination with K was more effective to alleviate water stress than K alone. Increasing soil water level from FC1 to FC2 often had a positive impact on values of most studied parameters. The Si 1 00K + (FC1) and Si 5 0K + (FC2) treatments gave high enough amounts of N 2 -fixation, higher dry matter production and greater nitrogen yield. The percent increments of total N 2 -fixed in the above mentioned treatments were 51 and 47% over their controls, respectively. On the other hand, increasing leaves dry matter in response to the solely added Si (Si 5 0K - and Si 1 00K - ) is associated with lower Δ 13 C under both watering regimes. This may indicate that Si fertilization had a beneficial effect on water use efficiency (WUE). Hence, Δ 13 C could be an adequate indicator of WUE in response to the exogenous supply of silicon to chickpea plants. Our results highlight that Si is not only involved in amelioration of growth and in maintaining of water status but it can be considered as an important element for the symbiotic performance of chickpea plants. It can be concluded that synergistic effect of silicon and potassium fertilization with adequate irrigation improves growth and nitrogen fixation in chickpea plants.In barley plants, solely added K or in combination with adequate rate of Si (Si 1 00) were more effective in alleviating water stress and producing higher yield in barley plants than solely added Si. However, the latter nutrient was found to be more effective than the former in producing

Quantification of the impact of macrophytes on oxygen dynamics and nitrogen retention in a vegetated lowland river

Science.gov (United States)

Desmet, N. J. S.; Van Belleghem, S.; Seuntjens, P.; Bouma, T. J.; Buis, K.; Meire, P.

When macrophytes are growing in the river, the vegetation induces substantial changes to the water quality. Some effects are the result of direct interactions, such as photosynthetic activity or nutrient uptake, whereas others may be attributed to indirect effects of the water plants on hydrodynamics and river processes. This research focused on the direct effect of macrophytes on oxygen dynamics and nutrient cycling. Discharge, macrophyte biomass density, basic water quality, dissolved oxygen and nutrient concentrations were in situ monitored throughout the year in a lowland river (Nete catchment, Belgium). In addition, various processes were investigated in more detail in multiple ex situ experiments. The field and aquaria measurement results clearly demonstrated that aquatic plants can exert considerable impact on dissolved oxygen dynamics in a lowland river. When the river was dominated by macrophytes, dissolved oxygen concentrations varied from 5 to 10 mg l -1. Considering nutrient retention, it was shown that the investigated in-stream macrophytes could take up dissolved inorganic nitrogen (DIN) from the water column at rates of 33-50 mg N kgdry matter-1 h. And DIN fluxes towards the vegetation were found to vary from 0.03 to 0.19 g N ha -1 h -1 in spring and summer. Compared to the measured changes in DIN load over the river stretch, it means that about 3-13% of the DIN retention could be attributed to direct nitrogen uptake from the water by macrophytes. Yet, the role of macrophytes in rivers should not be underrated as aquatic vegetation also exerts considerable indirect effects that may have a greater impact than the direct fixation of nutrients into the plant biomass.

Application of Response Surface Methodology for Optimization of Urea Grafted Multiwalled Carbon Nanotubes in Enhancing Nitrogen Use Efficiency and Nitrogen Uptake by Paddy Plants

Directory of Open Access Journals (Sweden)

Norazlina Mohamad Yatim

2016-01-01

Full Text Available Efficient use of urea fertilizer (UF as important nitrogen (N source in the world’s rice production has been a concern. Carbon-based materials developed to improve UF performance still represent a great challenge to be formulated for plant nutrition. Advanced N nanocarrier is developed based on functionalized multiwall carbon nanotubes (f-MWCNTs grafted with UF to produce urea-multiwall carbon nanotubes (UF-MWCNTs for enhancing the nitrogen uptake (NU and use efficiency (NUE. The grafted N can be absorbed and utilized by rice efficiently to overcome the N loss from soil-plant systems. The individual and interaction effect between the specified factors of f-MWCNTs amount (0.10–0.60 wt% and functionalization reflux time (12–24 hrs with the corresponding responses (NUE, NU were structured via the Response Surface Methodology (RSM based on five-level CCD. The UF-MWCNTs with optimized 0.5 wt% f-MWCNTs treated at 21 hrs reflux time achieve tremendous NUE up to 96% and NU at 1180 mg/pot. Significant model terms (p value < 0.05 for NUE and NU responses were confirmed by the ANOVA. Homogeneous dispersion of UF-MWCNTs was observed via FESEM and TEM. The chemical changes were monitored by FT-IR and Raman spectroscopy. Hence, this UF-MWCNTs’ approach provides a promising strategy in enhancing plant nutrition for rice.

Influence of heterogeneous ammonium availability on bacterial community structure and the expression of nitrogen fixation and ammonium transporter genes during in situ bioremediation of uranium-contaminated groundwater

Energy Technology Data Exchange (ETDEWEB)

Mouser, P.J.; N' Guessan, A.L.; Elifantz, H.; Holmes, D.E.; Williams, K.H.; Wilkins, M.J.; Long, P.E.; Lovley, D.R.

2009-04-01

The impact of ammonium availability on microbial community structure and the physiological status and activity of Geobacter species during in situ bioremediation of uranium-contaminated groundwater was evaluated. Ammonium concentrations varied by as much as two orders of magnitude (<4 to 400 {micro}M) across the study site. Analysis of 16S rRNA gene sequences suggested that ammonium influenced the composition of the microbial community prior to acetate addition with Rhodoferax species predominating over Geobacter species at the site with the highest ammonium, and Dechloromonas species dominating at sites with lowest ammonium. However, once acetate was added, and dissimilatory metal reduction was stimulated, Geobacter species became the predominant organisms at all locations. Rates of U(VI) reduction appeared to be more related to the concentration of acetate that was delivered to each location rather than the amount of ammonium available in the groundwater. In situ mRNA transcript abundance of the nitrogen fixation gene, nifD, and the ammonium importer gene, amtB, in Geobacter species indicated that ammonium was the primary source of nitrogen during in situ uranium reduction, and that the abundance of amtB transcripts was inversely correlated to ammonium levels across all sites examined. These results suggest that nifD and amtB expression by subsurface Geobacter species are closely regulated in response to ammonium availability to ensure an adequate supply of nitrogen while conserving cell resources. Thus, quantifying nifD and amtB expression appears to be a useful approach for monitoring the nitrogen-related physiological status of Geobacter species in subsurface environments during bioremediation. This study also emphasizes the need for more detailed analysis of geochemical/physiological interactions at the field scale, in order to adequately model subsurface microbial processes.

Indications on continued nitrogen uptake in Scots pine roots after clear-felling

Energy Technology Data Exchange (ETDEWEB)

Albrektson, A.; Valinger, E.; Leijon, B.; Sjoegren, H.; Sonesson, J.

1997-11-01

A study was performed in a 150 years old Scots pine (Pinus sylvestris L.) stand situated on a sandy moor in northern Sweden. Two plots were to be compared, and in June 1993 one was clear-felled. Even if reduced with approximately 50%, a significant fine root (diameter < 2 mm) growth was noticed at least up to one year after the clear-felling. For medium roots (diameters 2-4 and 4-6 mm) nitrogen content in root-wood and root-bark samples from the clear-felling, as compared to the reference plot, were 30-50% higher two months after the clear-felling. The difference did not increase in later comparisons. N-content in bark and wood buttress did not differ during the period studied, except for a higher percentage in bark at the clear-felling after two summers. This was believed to be a result of decomposition. The results indicate a maintained physiological activity in the stump-root system of Scots pine at least for one year at this site. An active uptake of N in roots of cut trees may influence leaching after clear-felling, the forage value of roots, and root decomposition rate and also maintain root competition with standing trees after thinning. 40 refs, 1 fig, 2 tabs

Crop uptake and leaching losses of 15N labelled fertilizer nitrogen in relation to waterlogging of clay and sandy loam soils

International Nuclear Information System (INIS)

Webster, C.P.; Belford, R.K.; Cannell, R.Q.

1986-01-01

Ammonium nitrate fertilizer, labelled with 15 N, was applied in spring to winter wheat growing in undisturbed monoliths of clay and sandy loam soil in lysimeters; the rates of application were respectively 95 and 102 kg N ha -1 in the spring of 1976 and 1975. Crops of winter wheat, oilseed rape, peas and barley grown in the following 5 or 6 years were treated with unlabelled nitrogen fertilizer at rates recommended for maximum yields. During each year of the experiments the lysimeters were divided into treatments which were either freely drained or subjected to periods of waterlogging. Another labelled nitrogen application was made in 1980 to a separate group of lysimeters with a clay soil and a winter wheat crop to study further the uptake of nitrogen fertilizer in relation to waterlogging. In the first growing season, shoots of the winter wheater at harvest contained 46 and 58% of the fertilizer nitrogen applied to the clay and sandy loam soils respectively. In the following year the crops contained a further 1-2% of the labelled fertilizer, and after 5 and 6 years the total recoveries of labelled fertilizer in the crops were 49 and 62% on the clay and sandy loam soils respectively. In the first winter after the labelled fertilizer was applied, less than 1% of the fertilizer was lost in the drainage water, and only about 2% of the total nitrogen (mainly nitrate) in the drainage water from both soils was derived from the fertilizer

Nitrogen uptake by wheat seedlings, interactive effects of four nitrogen sources: NO3-, NO2-, NH4+, and urea

Science.gov (United States)

Criddle, R. S.; Ward, M. R.; Huffaker, R. C.

1988-01-01

The net influx (uptake) rates of NO3-, NH4+, NO2-, and urea into roots of wheat (Triticum aestivum cv Yecora Rojo) seedlings from complete nutrient solutions containing all four compounds were monitored simultaneously. Although urea uptake was too slow to monitor, its presence had major inhibitory effects on the uptake of each of the other compounds. Rates of NO3-, NH4+, and NO2- uptake depended in a complex fashion on the concentration of all four N compounds. Equations were developed which describe the uptake rates of each of the compounds, and of total N, as functions of concentrations of all N sources. Contour plots of the results show the interactions over the range of concentrations employed. The coefficients of these equations provide quantitative values for evaluating primary and interactive effects of each compound on N uptake.

Effect of Nitrogen Foliar Application on Canola Yield (Brassica napus L. and Nitrogen Efficiency across Different Sowing Dates

Directory of Open Access Journals (Sweden)

S Doori

2016-12-01

Full Text Available Introduction Between oil seeds, from the quality, quantity and nutrition index point of view, canola has the top level . Because of the solubility of N fertilizers, the time of urea application, is very important and one of the main reasons of the reduction in N application efficiency is utilization of urea in an inappropriate time. By precisely foliar application of nitrogen, the efficiency of nitrogen transformation to the grain will be very high because in this method the leaf is considered the main organ of nitrogen uptake and a low amount of absorbed nitrogen was transferred to the root and entered the soil. The more division of N application in growth stages and in accordance with plant need and foliar application result in increasing nitrogen use efficiency. The delay in sowing will result in the reduction of yield and this is due to low LAI, and thus low radiation absorb in vegetable phase and shorter reproductive phase with high temperature in flowering and subsequent stages that result in low prolific silique and make disorder in transferring stored material to grain. In this experiment using N foliar application to decrease the adverse effect of delay in sowing is objective. Materials and Methods The experiment was conducted in 2013-2014 in Ramin Agriculture and Natural Resource University of Khuzestan. Experiment was conducted as split plots in a randomized complete blocks design with three replications. In this experiment sowing date]optimum sowing (27 November, 17 December and late sowing (30 December [were assigned to main plots and several time of N-foliar application with 5 percent density from urea (20 liter per ha, ]TO (control, T1 (foliar N application in rosette stage, T2 (foliar N application in budding stage, T3 (foliar N application in flowering stage[ were placed in sub-plots in randomized way. Fertilizing was based on the results of soil examination. Therefore, 162 kg ha-1 of pure nitrogen (from resource urea in the way

4H-SiC surface energy tuning by nitrogen up-take

Energy Technology Data Exchange (ETDEWEB)

Pitthan, E., E-mail: eduardo.pitthan@ufrgs.br [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, NJ 08854 (United States); PGMICRO, UFRGS, 91509-900, Porto Alegre, RS (Brazil); Amarasinghe, V.P. [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, NJ 08854 (United States); Xu, C.; Gustafsson, T. [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, NJ 08854 (United States); Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854 (United States); Stedile, F.C. [PGMICRO, UFRGS, 91509-900, Porto Alegre, RS (Brazil); Instituto de Química, UFRGS, 91509-900, Porto Alegre, RS (Brazil); Feldman, L.C. [Institute for Advanced Materials, Devices and Nanotechnology, Rutgers University, Piscataway, NJ 08854 (United States); Department of Physics and Astronomy, Rutgers University, Piscataway, NJ 08854 (United States)

2017-04-30

Highlights: • Wettability modification of 4H-SiC as a function of nitrogen adsorption is reported. • SiC surface energy was significantly reduced as nitrogen was incorporated. • Modifications obtained were proved to be inert to etching and stable against time. • Variable control of SiC surface provides new opportunities for biomedical applications. - Abstract: Surface energy modification and surface wettability of 4H silicon carbide (0001) as a function of nitrogen adsorption is reported. The surface wettability is shown to go from primarily hydrophilic to hydrophobic and the surface energy was significantly reduced with increasing nitrogen incorporation. These changes are investigated by x-ray photoelectron spectroscopy and contact angle measurements. The surface energy was quantitatively determined by the Fowkes model and interpreted primarily in terms of the variation of the surface chemistry with nitrogen coverage. Variable control of SiC surface energies with a simple and controllable atomic additive such as nitrogen that is inert to etching, stable against time, and also effective in electrical passivation, can provide new opportunities for SiC biomedical applications, where surface wetting plays an important role in the interaction with the biological interfaces.

Anthropogenic nitrogen input traced by means of {delta} {sup 15}N values in macroalgae: Results from in-situ incubation experiments

Energy Technology Data Exchange (ETDEWEB)

Deutsch, Barbara [Baltic Sea Research Institute, Seestr. 15, 18119 Rostock (Germany)]. E-mail: barbara.deutsch@io-warnemuende.de; Voss, Maren [Baltic Sea Research Institute, Seestr. 15, 18119 Rostock (Germany)

2006-08-01

The macroalgae species Fucus vesiculosus (Phaeophyta), Polysiphonia sp., and Ceramium rubrum (Rhodophyta) originally grown at an unpolluted brackish site of the southern Baltic Sea were incubated for 10 and 14 days at 12 stations along a salinity gradient in a highly polluted estuary. We have expected an adaptation of the initially low {delta} {sup 15}N values to the higher ones within the incubation period. In addition to the macroalgae the {delta} {sup 15}N values of NO{sub 3} {sup -} were measured to evaluate fractionation processes of the source nitrate. Inside the estuary, {delta} {sup 15}N-NO{sub 3} {sup -} values were 6.2-9.7 per mille , indicating anthropogenic nitrogen sources. The red macroalgae adequately reflected the nitrate isotope values in the surrounding waters, whereas for F. vesiculosus the results were not that clear. The reasons were assumed to be higher initial {delta} {sup 15}N values of F. vesiculosus and presumably a too slow nitrogen uptake and growth rate. The method of macroalgae incubations seems suitable as a simple monitoring to study the influence of anthropogenic nitrogen loading in an estuarine environment.

Fertilizer residence time affects nitrogen uptake efficiency and growth of sweet corn

NARCIS (Netherlands)

Zotarelli, L.; Scholberg, J.M.S.; Dukes, M.D.; Munoz-Carpena, R.

2008-01-01

Understanding plant N uptake dynamics is critical for increasing fertilizer N uptake efficiency (FUE) and minimize the risk of N leaching. The objective of this research was to determine the effect of residence time of N fertilizer on N uptake and FUE of sweet corn. Plants were grown in 25 L columns

Isotopic and non-isotopic estimations of fertilizer nitrogen uptake by wheat

International Nuclear Information System (INIS)

Hamid, A.; Ahmad, M.

1990-01-01

Recoveries of fertilizer N in wheat (MexiPak-65) grown in a field experiment were calculated by difference methods including linear regression of total nitrogen in wheat plant, nitrogen 15 method and linear regression of fertilizer. The difference method overestimated recoveries of applied fertilizer at the rates of application when compared to the nitrogen 15 method. Similarly linear regression of total N in wheat on rates of N over estimated recoveries by 25% at the three rates. The difference method of calculating the recoveries of fertilizer N in wheat could give values similar to those calculated by nitrogen 15 method when the minimal N treatment was used as a base instead of zero-N. (orig./A.B.)

Model analysis of the influence of gas diffusivity in soil on CO and H2 uptake

International Nuclear Information System (INIS)

Yonemura, S.; Yokozawa, M.; Kawashima, S.; Tsuruta, H.

2000-01-01

CO and H 2 uptake by soil was studied as a diffusion process. A diffusion model was used to determine how the surface fluxes (net deposition velocities) were controlled by in-situ microbial uptake rates and soil gas diffusivity calculated from the 3-phase system (solid, liquid, gas) in the soil. Analytical solutions of the diffusion model assuming vertical uniformity of soil properties showed that physical properties such as air-filled porosity and soil gas diffusivity were more important in the uptake process than in the emission process. To incorporate the distribution of in-situ microbial uptake, we used a 2-layer model incorporating 'a microbiologically inactive layer and an active layer' as suggested from experimental results. By numerical simulation using the 2-layer model, we estimated the effect of several factors on deposition velocities. The variations in soil gas diffusivity due to physical properties, i.e., soil moisture and air-filled porosity, as well as to the depth of the inactive layer and in-situ microbial uptake, were found to be important in controlling deposition velocities. This result shows that the diffusion process in soil is critically important for CO and H 2 uptake by soil, at least in soils with higher in-situ uptake rates and/or with large variation in soil moisture. Similar uptake rates and the difference in deposition velocity between CO and H 2 may be attributable to differences in CO and H 2 molecular diffusivity. The inactive layer is resistant to diffusion and creates uptake limits in CO and H 2 by soil. The coupling of high temperature and a thick inactive layer, common in arid soils, markedly lowers net CO deposition velocity. The temperature for maximum uptake of CO changes with depth of the inactive layer

Uptake of different forms of nitrogen by hyphae of arbuscular mycorrhizal fungi

International Nuclear Information System (INIS)

Li Xia; Zhang Junling

2007-01-01

A two-compartment incorporating air-gap device and 15 N-labeling technique was used to investigate the uptake of different forms of N by arbuscular mycorrhizal fungi (AMF). Maize (Zea mays L.) was in association with Glomus mosseae, or Glomus intraradices. Solutions labeled with different forms of 15 N were supplied to the hyphae compartment 48 h before harvesting. The results showed that the uptake capability of 15 N varied with fungi species and N forms supplied. Percentage of 15 N taken up over 48 h by G. intraradices was higher than that by G. mosseae. The uptake capability of 15 N by AMF was in the order of 15 NH 4 + > 15 N-Gln> 15 N-Gly> 15 NO 3 - . 15 N uptake by AMF hyphae accounted for 0.005-0.032% of total N uptake. (authors)

Valuing multiple eelgrass ecosystem services in Sweden: fish production and uptake of carbon and nitrogen

Directory of Open Access Journals (Sweden)

Scott Glenn Cole

2016-01-01

Full Text Available Valuing nature’s benefits in monetary terms is necessary for policy-makers facing trade-offs in how to spend limited financial resources on environmental protection. We provide information to assess trade-offs associated with the management of seagrass beds, which provide a number of ecosystem services, but are presently impacted by many stressors. We develop an interdisciplinary framework for valuing multiple ecosystem services and apply it to the case of eelgrass (Zostera marina, a dominant seagrass species in the northern hemisphere. We identify and quantify links between three eelgrass functions (habitat for fish, carbon and nitrogen uptake and economic goods in Sweden, quantify these using ecological endpoints, estimate the marginal average value of the impact of losing one hectare of eelgrass along the Swedish northwest coast on welfare in monetary terms, and aggregate these values while considering double-counting. Over a 20 to 50 year period we find that compared to unvegetated habitats, a hectare of eelgrass, including the organic material accumulated in the sediment, produces an additional 626 kg cod fishes and 7,535 wrasse individuals and sequesters 98.6 ton carbon and 466 kg nitrogen. We value the flow of future benefits associated with commercial fishing, avoided climate change damages, and reduced eutrophication at 170,000 SEK in 2014 (20,700 US$ or 11,000 SEK (1,300 US$ annualized at 4%. Fish production, which is the most commonly valued ecosystem service in the seagrass literature, only represented 25% of the total value whereas a conservative estimate of nitrogen regulation constituted 46%, suggesting that most seagrass beds are undervalued. Comparing these values with historic losses of eelgrass we show that the Swedish northwest coast has suffered a substantial reduction in fish production and mineral regulation. Future work should improve the understanding of the geographic scale of eelgrass functions, how local variables

Response of bread wheat to increasing mustard meal nitrogen ...

African Journals Online (AJOL)

Greenhouse experiment on the nitrogen uptake from the mustard meal using 15N showed significant difference on both soil types. On the Vertisol the per cent nitrogen derived from the meal and per cent nitrogen use efficiency varied from 18 to 40 and from 18 to 62%, respectively. On the Nitosol, these values varied from 25 ...

Enhanced nitrogen deposition over China

Energy Technology Data Exchange (ETDEWEB)

Liu, Xuejun; Zhang, Ying; Han, Wenxuan; Tang, Aohan; Shen, Jianlin; Cui, Zhenling; Christie, Peter; Zhang, Fusuo [College of Resources and Environmental Sciences, China Agricultural University, Beijing 100193 (China); Vitousek, Peter [Department of Biology, Stanford University, Stanford, California 94305 (United States); Erisman, Jan Willem [VU University Amsterdam, 1081 HV Amsterdam (Netherlands); Goulding, Keith [The Sustainable Soils and Grassland Systems Department, Rothamsted Research, Harpenden AL5 2JQ (United Kingdom); Fangmeier, Andreas [Institute of Landscape and Plant Ecology, University of Hohenheim, 70593 Stuttgart (Germany)

2013-02-28

China is experiencing intense air pollution caused in large part by anthropogenic emissions of reactive nitrogen. These emissions result in the deposition of atmospheric nitrogen (N) in terrestrial and aquatic ecosystems, with implications for human and ecosystem health, greenhouse gas balances and biological diversity. However, information on the magnitude and environmental impact of N deposition in China is limited. Here we use nationwide data sets on bulk N deposition, plant foliar N and crop N uptake (from long-term unfertilized soils) to evaluate N deposition dynamics and their effect on ecosystems across China between 1980 and 2010. We find that the average annual bulk deposition of N increased by approximately 8 kilograms of nitrogen per hectare (P < 0.001) between the 1980s (13.2 kilograms of nitrogen per hectare) and the 2000s (21.1 kilograms of nitrogen per hectare). Nitrogen deposition rates in the industrialized and agriculturally intensified regions of China are as high as the peak levels of deposition in northwestern Europe in the 1980s, before the introduction of mitigation measures. Nitrogen from ammonium (NH4+) is the dominant form of N in bulk deposition, but the rate of increase is largest for deposition of N from nitrate (NO3-), in agreement with decreased ratios of NH3 to NOx emissions since 1980. We also find that the impact of N deposition on Chinese ecosystems includes significantly increased plant foliar N concentrations in natural and semi-natural (that is, non-agricultural) ecosystems and increased crop N uptake from long-term-unfertilized croplands. China and other economies are facing a continuing challenge to reduce emissions of reactive nitrogen, N deposition and their negative effects on human health and the environment.

Terrestrial nitrogen cycles: Some unanswered questions

Science.gov (United States)

Vitousek, P.

1984-01-01

Nitrogen is generally considered to be the element which most often limits the growth of plants in both natural and agricultural ecosystems. It regulates plant growth because photosynthetic rates are strongly dependent on the concentration of nitrogen in leaves, and because relatively large mounts of protein are required for cell division and growth. Yet nitrogen is abundant in the biosphere - the well-mixed pool in the atmosphere is considered inexhaustible compared to biotic demand, and the amount of already fixed organic nitrogen in soils far exceeds annual plant uptake in terrestrial ecosystems. In regions where natural vegetation is not nitrogen limited, continuous cultivation induces nitrogen deficiency. Nitrogen loss from cultivated lands is more rapid than that of other elements, and nitrogen fertilization is generally required to maintain crop yield under any continuous system. The pervasiveness of nitrogen deficiency in many natural and most managed sites is discussed.

Nitrogen release, tree uptake, and ecosystem retention in a mid-rotation loblolly pine plantation following fertilization with 15N-enriched enhanced efficiency fertilizers.

OpenAIRE

Werner, Amy

2013-01-01

Nitrogen is the most frequently limiting nutrient in southern pine plantations.  Previous studies found that only 10 to 25% of applied urea fertilizer N is taken up by trees.  Enhanced efficiency fertilizers could increase tree uptake efficiency by controlling the release of N and/or stabilize N.  Three enhanced efficiency fertilizers were selected as a representation of fertilizers that could be used in forestry: 1) NBPT treated urea (NBPT urea), 2) polymer coated urea (PC urea), and 3) mono...

Adaptations of hepatic amino acid uptake and net utilisation contributes to nitrogen economy or waste in lambs fed nitrogen- or energy-deficient diets.

Science.gov (United States)

Kraft, G; Ortigues-Marty, I; Durand, D; Rémond, D; Jardé, T; Bequette, B; Savary-Auzeloux, I

2011-04-01

We investigated the effect of relative changes in dietary nitrogen (N) and energy supply and the subsequent variations in net portal appearance (NPA) of nitrogenous and energy nutrients on the net amino acid (AA) uptake by the liver and net N supply to the peripheral tissues. Six lambs were catheterised across the splanchnic tissues and received, in a replicated Latin square, one of three dietary treatments. The diets were formulated to either match the requirements of N and energy (C), or supply only 0.8 of the N requirement (LN) or 0.8 of the energy requirement (LE). Net fluxes of AA and urea-N were measured across the portal-drained viscera, and estimation of arterial hepatic flow allowed the estimation of hepatic fluxes. Catheters were implanted into the portal and hepatic veins as well as in the abdominal aorta for the measurement of AA fluxes. Animals fed the LN diet showed more efficient N retention (0.59 of digested N) than did the C and LE diet (0.50 and 0.33, respectively; P < 0.001). The NPA of total AA-N for the LN diet was only 0.60 of the value measured for the control (C) diet (P < 0.01). Despite this, the total estimated AA-N net splanchnic fluxes were not significantly different across the three diets (3.3, 1.9 and 2.6 g total AA-N/day for C, LN and LE, respectively, P = 0.52). Thus, different metabolic regulations must have taken place across the liver between the three experimental diets. A combination of decreased net uptake of total AA-N by the liver of animals in the LN diet (0.61 of the C diet; P = 0.002) and reduced urinary urea-N production (0.52 of the C diet; P = 0.001) spared AA from catabolism in the LN diet relative to the other two diets. For the LE diet, the urinary urea-N output was 1.3 times the value of the C diet (P = 0.01). This may relate to an increased catabolism of AA by the muscle and/or, to a lesser extent, to an increased utilisation of AA for gluconeogenesis in the liver. These effects may explain the reduced whole body

Uptake of Nitrogen Dioxide by Quercus robur - is There a Compensation Point?

Science.gov (United States)

Thielmann, A.; Chaparro, G.; Kuhn, U.; Dindorf, T.; Lehmann, L.; Kortner, M.; Tritsch, C.; Kesselmeier, J.; Meixner, F. X.

2003-12-01

Within the German Atmospheric-Research-Program 2000, the project ECHO (Emission and CHemical Transformation of Biogenic Volatile Organic Compounds) has been carried out in a mixed forest stand during the summer of 2002. The contribution of the Max Planck Institute for Chemistry was the complete characterization of the NOx-flux within the forest, including (a) the quantification of the biogenic NO-release from forest soils, (b) the measurement of the vertical distribution of NOx within and above the canopy and (c) the turbulent transport within and above the forest. The profile measurements allow to identify the participating processes: soil NO emission and subsequent titration of emitted NO by ozone, advection of highly polluted air masses to the site and the uptake of nitrogen dioxide within the crown area. The latter, i.e. the role of vegetation in the NOx-budget within a particular ecosystem is still a matter in controversy, which translates into considerable uncertainties in the global NOx-budget. To assess this issue, dynamic cuvette measurements were performed on a Quercus robur branch. The concurrent measurement of plant physiological (leaf temperature, stomatal conductance, transpiration and photosynthesis/respiration) and ambient parameters (radiation, ambient NOx mixing ratios) allows to put the exchange rate into context. The question whether a compensation point may be identified will especially be addressed.

Isotope studies on the comparative efficiency of nitrogenous sources

Energy Technology Data Exchange (ETDEWEB)

Dev, G; Rennie, D A [Saskatchewan Univ., Saskatoon (Canada). Dept. of Soil Science

1979-03-01

In a growth chamber experiment with /sup 15/N-labelled potassium nitrate, ammonium sulphate and urea at 75 and 150kg nitrogen/ha and ammonium nitrate at 150kg nitrogen/ha, nitrogen application produced significant responses of dry matter yield and total nitrogen uptake by shoot and root of barley in chernozemic dark brown Elstow silt loam and deep black Hoey clay soil. Total nitrogen removal per pot and isotope-derived criteria, viz. percentage nitrogen derived from fertilizer, 'A' value and percentage fertilizer nitrogen utilization, indicated that potassium nitrate was the most efficient and urea the least.

Factors affecting ammonium uptake in streams - an inter-biome perspective

Science.gov (United States)

Jackson R Webster; Partick J. Mulholland; Jennifer L. Tanks; H. Maurice Valett; Walter K. Dodds; Bruce J. Peterson; William B. Bowden; Clifford N. Dahm; Stuart Findlay; Stanley V. Gregory; Nancy B. Grimm; Stephen K. Hamilton; Sherri L. Johnson; Eugenia Marti; William H. McDowell; Judy L. Meyer; Donna D. Morrall; Steven A. Thomas; Wilfred M. Wollhem

2003-01-01

1. The Lotic Intersite Nitrogen experiment (LINX) was a coordinated study of the relationships between North American biomes and factors governing ammonium uptake in streams. Our objective was to relate inter-biome variability of ammonium uptake to physical, chemical and biological processes. 2. Data were collected from 11 streams ranging from arctic to tropical and...

Effects of inorganic nitrogen form on growth, morphology, N uptake, and nutrient allocation in hybrid Napier grass (Pennisetum purpureum × Pennisetum americanum cv. Pakchong1)

DEFF Research Database (Denmark)

Jampeetong, Arunothai; Brix, Hans; Kantawanichkul, Suwasa

2014-01-01

in such systems. We studied the effects of inorganic nitrogen form (NH4 +, NH4NO3 or NO3 -) on growth, morphology, N uptake, water content and mineral allocation in this species under hydroponic conditions at equimolar concentrations (500μmolNL-1). Generally, the N-form significantly affected growth, biomass...

Uptake of crude petroleum hydrocarbons by mudflat bacteria ...

African Journals Online (AJOL)

SERVER

2007-08-06

Aug 6, 2007 ... bacteria exposed to nitrogenous fertilizer plant ... accompanied by a rapid decline in the level of crude petroleum in the amended .... conductivity, turbidity, salinity, dissolved oxygen (fresh sample only) ... Nutrient uptake was.

Application of Response Surface Methodology for Optimization of Urea Grafted Multi walled Carbon Nano tubes in Enhancing Nitrogen Use Efficiency and Nitrogen Uptake by Paddy Plants

International Nuclear Information System (INIS)

Yatim, N. M.; Shaaban, A.; Dimin, M. F.; Yusof, F.; Abo Razak, J.

2016-01-01

Efficient use of urea fertilizer (UF) as important nitrogen (N) source in the world’s rice production has been a concern. Carbon-based materials developed to improve UF performance still represent a great challenge to be formulated for plant nutrition. Advanced N nano carrier is developed based on functionalized multi wall carbon nano tubes (f-MWCNTs) grafted with UF to produce urea-multi wall carbon nano tubes (UF-MWCNTs) for enhancing the nitrogen uptake (NU) and use efficiency (NUE). The grafted N can be absorbed and utilized by rice efficiently to overcome the N loss from soil-plant systems. The individual and interaction effect between the specified factors of f-MWCNTs amount (0.10-0.60 wt%) and functionalization reflux time (12-24 hrs) with the corresponding responses (NUE, NU) were structured via the Response Surface Methodology (RSM) based on five-level CCD. The UF-MWCNTs with optimized 0.5 wt% f-MWCNTs treated at 21 hrs reflux time achieve tremendous NUE up to 96% and NU at 1180 mg/pot. Significant model terms (Þ value < 0.05) for NUE and NU responses were confirmed by the ANOVA. Homogeneous dispersion of UF-MWCNTs was observed via FESEM and TEM. The chemical changes were monitored by FT-IR and Raman spectroscopy. Hence, this UF-MWCNTs’ approach provides a promising strategy in enhancing plant nutrition for rice.

Effect of gamma radiation on the nitrogen metabolism of Paecilomyces Violacea

International Nuclear Information System (INIS)

Salama, A.H.; Nadia, M.; Elzawahry, Y.A.; Abo Elkhair, I.A.

1989-01-01

Quantitative variabilities could be noticed in the nitrogen utilization and mycelial content of mats arising from gamma irradiated and non-irradiated Inocula of P.Violacea. The two lowest doses, 0.1 and 0.25 KGy, showed an increase in nitrate uptake and nitrogen utilization more than control by 7.43 and 15.61% for nitrate uptake and 8.33 and 14.89 for nitrogen utilization respectively, while the higher doses (0.5 up to 3.0 KGy) were inhibitory to the above parameters and also to protein synthesis. The chemical changes in the composition of fungal mats reveal that the peptide-N was the highest in amount as compared with the other nitrogen fractions. The protein-N was second in rank of quantity followed by the amino-N, while the nitrate-N was the least in amount compared to other nitrogen fractions at all radiation treatments

Nitrogen utilization efficiency and nitrogen nutrition of rice crops at MADA using the microplot nitrogen balance method

International Nuclear Information System (INIS)

Ahmad Nazrul Abd Wahid; Abdul Razak Ruslan; Latiffah Norddin; Hazlina Abdullah; Khairuddin Abdul Rahim

2004-01-01

Nitrogen (N) is a very important nutrient for rice crops and is a main component of protein. Nitrogen is essential in the production of plant chlorophyll and involves in vegetative and fruit growth and development processes. Nitrogen is a critical input and exert high cost in rice crop production. Nitrogen fertilizer is not fully utilised by the rice crop; some is lost due the processes of vaporization, hydrolysis, erosion, leaching and used by other plants and microorganisms. Several agronomic practices have been studied and adopted in this country with the purpose of increasing the efficiency nitrogen fertilizer utilization and thus, reducing the output cost for rice crops. The microplot nitrogen balance method is one of the methods used to determine uptake efficiency of nitrogen fertilizers by rice crops. In this research, the microplot of 1 m x 1 m squares in paddy plot were used, to ensure that sequential sampling was done at predetermined areas. Scheduled monthly sampling of soil and rice crops was conducted until the mature stage, harvest and post-harvest period. This MINT-MADA cooperative project contains the elements of information sharing on fertilizer efficiency measurement methods by using the N-15 isotopic tracer technique and the N-balance technique in soil, besides the cooperation on use of infrastructure and facilities, expertise and labour. (Author)

Nitrogen uptake by heterotrophic bacteria and phytoplankton in the nitrate-rich Thames estuary

NARCIS (Netherlands)

Middelburg, J.J.; Nieuwenhuize, J.

2000-01-01

The uptake of ammonium, nitrate, amino acids and urea was examined in the nitrate-rich Thames estuary and adjacent area in the North Sea during February 1999. The majority of uptake was by heterotrophic bacteria, as demonstrated by addition of a prokaryotic inhibitor that lowered uptake rates by 82,

Comparison of chromium and nickel uptake of plants grown in different soils

Energy Technology Data Exchange (ETDEWEB)

Vago, I. [University of Agriculture, Faculty of Agronomy, H-4015 Debrecen, P.O. Box 36 (Hungary); Gyoeri, Z. [University of Agriculture, Faculty of Agronomy, H-4015 Debrecen, P.O. Box 36 (Hungary); Loch, J. [University of Agriculture, Faculty of Agronomy, H-4015 Debrecen, P.O. Box 36 (Hungary)

1996-03-01

The chromium and nickel uptake of ryegrass has been examined in pot experiments in extremely different soils, poor sandy and fertile black chernozem. The effect of calcium carbonate doses and nitrogen supply on heavy metal uptake of the plant has been studied for chromium and nickel loadings (0-100 mg/kg Cr{sup 3+} or Ni{sup 2+}) applied as inorganic salts. The ability to uptake Cr{sup 3+} and Ni{sup 2+} differs significantly and is highly affected by the characteristics of soils, and depends on the metal investigated. The heavy metal uptake of the plant differs significantly in acid, colloid deficient sandy soils; while artificial chromium contamination did not modify the dry-matter production in the pots in either soil, a large quantity of nickel reduced the yields significantly. Nitrogen application did not change significantly the uptake of heavy metals. Lime application reduced the Ni{sup 2+} uptake of plants considerably, especially in sandy soil. In case of a calcium carbonate addition the dry-matter production of the plant was not affected by nickel. In chernozem soil the effect of lime application - i.e., the reduction of nickel uptake - was of a lesser degree. The significantly lesser Cr{sup 3+} uptake was further limited by a calcium carbonate application for both soils studied. A graphic presentation of these effects is given. (orig.). With 3 figs., 3 tabs.

No effect of NOS inhibition on skeletal muscle glucose uptake during in situ hindlimb contraction in healthy and diabetic Sprague-Dawley rats.

Science.gov (United States)

Hong, Yet Hoi; Betik, Andrew C; Premilovac, Dino; Dwyer, Renee M; Keske, Michelle A; Rattigan, Stephen; McConell, Glenn K

2015-05-15

Nitric oxide (NO) has been shown to be involved in skeletal muscle glucose uptake during contraction/exercise, especially in individuals with Type 2 diabetes (T2D). To examine the potential mechanisms, we examined the effect of local NO synthase (NOS) inhibition on muscle glucose uptake and muscle capillary blood flow during contraction in healthy and T2D rats. T2D was induced in Sprague-Dawley rats using a combined high-fat diet (23% fat wt/wt for 4 wk) and low-dose streptozotocin injections (35 mg/kg). Anesthetized animals had one hindlimb stimulated to contract in situ for 30 min (2 Hz, 0.1 ms, 35 V) with the contralateral hindlimb rested. After 10 min, the NOS inhibitor, N(G)-nitro-l-arginine methyl ester (l-NAME; 5 μM) or saline was continuously infused into the femoral artery of the contracting hindlimb until the end of contraction. Surprisingly, there was no increase in skeletal muscle NOS activity during contraction in either group. Local NOS inhibition had no effect on systemic blood pressure or muscle contraction force, but it did cause a significant attenuation of the increase in femoral artery blood flow in control and T2D rats. However, NOS inhibition did not attenuate the increase in muscle capillary recruitment during contraction in these rats. Muscle glucose uptake during contraction was significantly higher in T2D rats compared with controls but, unlike our previous findings in hooded Wistar rats, NOS inhibition had no effect on glucose uptake during contraction. In conclusion, NOS inhibition did not affect muscle glucose uptake during contraction in control or T2D Sprague-Dawley rats, and this may have been because there was no increase in NOS activity during contraction. Copyright © 2015 the American Physiological Society.

Representing leaf and root physiological traits in CLM improves global carbon and nitrogen cycling predictions

Science.gov (United States)

Ghimire, Bardan; Riley, William J.; Koven, Charles D.; Mu, Mingquan; Randerson, James T.

2016-06-01

In many ecosystems, nitrogen is the most limiting nutrient for plant growth and productivity. However, current Earth System Models (ESMs) do not mechanistically represent functional nitrogen allocation for photosynthesis or the linkage between nitrogen uptake and root traits. The current version of CLM (4.5) links nitrogen availability and plant productivity via (1) an instantaneous downregulation of potential photosynthesis rates based on soil mineral nitrogen availability, and (2) apportionment of soil nitrogen between plants and competing nitrogen consumers assumed to be proportional to their relative N demands. However, plants do not photosynthesize at potential rates and then downregulate; instead photosynthesis rates are governed by nitrogen that has been allocated to the physiological processes underpinning photosynthesis. Furthermore, the role of plant roots in nutrient acquisition has also been largely ignored in ESMs. We therefore present a new plant nitrogen model for CLM4.5 with (1) improved representations of linkages between leaf nitrogen and plant productivity based on observed relationships in a global plant trait database and (2) plant nitrogen uptake based on root-scale Michaelis-Menten uptake kinetics. Our model improvements led to a global bias reduction in GPP, LAI, and biomass of 70%, 11%, and 49%, respectively. Furthermore, water use efficiency predictions were improved conceptually, qualitatively, and in magnitude. The new model's GPP responses to nitrogen deposition, CO2 fertilization, and climate also differed from the baseline model. The mechanistic representation of leaf-level nitrogen allocation and a theoretically consistent treatment of competition with belowground consumers led to overall improvements in global carbon cycling predictions.

Nitrogen on Mars: Insights from Curiosity

Science.gov (United States)

Stern, J. C.; Sutter, B.; Jackson, W. A.; Navarro-Gonzalez, Rafael; McKay, Chrisopher P.; Ming, W.; Archer, P. Douglas; Glavin, D. P.; Fairen, A. G.; Mahaffy, Paul R.

2017-01-01

Recent detection of nitrate on Mars indicates that nitrogen fixation processes occurred in early martian history. Data collected by the Sample Analysis at Mars (SAM) instrument on the Curiosity Rover can be integrated with Mars analog work in order to better understand the fixation and mobility of nitrogen on Mars, and thus its availability to putative biology. In particular, the relationship between nitrate and other soluble salts may help reveal the timing of nitrogen fixation and post-depositional behavior of nitrate on Mars. In addition, in situ measurements of nitrogen abundance and isotopic composition may be used to model atmospheric conditions on early Mars.

Modeling continuous cultures of microalgae colimited by nitrogen and phosphorus.

Science.gov (United States)

Bougaran, Gaël; Bernard, Olivier; Sciandra, Antoine

2010-08-07

It is well documented that the combination of low nitrogen and phosphorus resources can lead to situations where colimitation of phytoplankton growth arises, yet the underlying mechanisms are not fully understood. Here, we propose a Droop-based model built on the idea that colimitation by nitrogen and phosphorus arises from the uptake of nitrogen. Indeed, since N-porters are active systems, they require energy that could be related to the phosphorus status of the cell. Therefore, we assumed that N uptake is enhanced by the P quota. Our model also accounts for the biological observations that uptake of a nutrient can be down-regulated by its own internal quota, and succeeds in describing the strong contrast for the non-limiting quotas under N-limited and P-limited conditions that was observed on continuous cultures with Selenastrum minutum and with Isochrysis affinis galbana. Our analysis suggests that, regarding the colimitation concept, N and P would be better considered as biochemically dependent rather than biochemically independent nutrients. Copyright 2010 Elsevier Ltd. All rights reserved.

Acid-promoted Bicyclization of Diaryl Alkynes: Synthesis of 2H-Indazoles with in situ Generated Diazonium Salt as Nitrogen Source.

Science.gov (United States)

Zhang, Cheng; Chang, Sailan; Dong, Shanliang; Qiu, Lihua; Xu, Xinfang

2018-06-08

An unprecedented transition-metal-free tandem bicyclization of diaryl alkynes has been disclosed, which provides a streamlined access to a range of polycyclic 2H-indazoles in high to excellent yields. The salient features of this reaction include readily available starting materials, good functional group compatibility, mild reaction conditions, no column chromatography, high bond-formation efficiency, and ease in further transformations. Notably, this is the first example for the synthesis of 2H-indazoles with in situ generated diazonium salt as the nitrogen source, and a mechanistic rationale involving an acid-promoted tandem diazonium salt formation/bicyclization process is discussed.

Nitrogen from mountain to fjord - Annual report 1993; Nitrogen fra fjell til fjord. Aarsrapport 1993

Energy Technology Data Exchange (ETDEWEB)

Kaste, Oe; Bechmann, M; Toerset, K

1994-07-01

``Nitrogen from mountain to fjord`` is an interdisciplinary research programme which studies the nitrogen cycle from deposition to discharge into the sea. The project includes investigation of the nitrogen budgets for two catchments and selected areas of mountain, heath, forest, crop land and fresh water. The main purpose of the project is to increase the knowledge of uptake and runoff of nitrogen and thus to improve the prediction of future effects on soil, forest, fresh water and fjords. The activities are concentrated about two water courses in Norway: Bjerkreimsvassdraget and Aulivassdraget. In Bjerkreimsvassdraget the nitrate concentration changed only little from 1992 to 1993. Relatively large variations in the nitrate concentrations were found in the forest and heath areas of the system. In Aulivassdraget the nitrogen concentration has changed considerably in 1992 and 1993. The maximum concentration measured in the main river was 13.2 mg N/l. In autumn 1992 and spring 1993 much nitrogen remained in the soil after the poor harvest of 1992 and at that time much nitrogen was carried away by the runoff. 16 refs., 19 figs., 16 tabs.

Nitrogen fixation, denitrification, and ecosystem nitrogen pools in relation to vegetation development in the Subarctic

DEFF Research Database (Denmark)

Sørensen, Pernille Lærkedal; Jonasson, Sven Evert; Michelsen, Anders

2006-01-01

Nitrogen (N) fixation, denitrification, and ecosystem pools of nitrogen were measured in three subarctic ecosystem types differing in soil frost-heaving activity and vegetation cover. N2-fixation was measured by the acetylene reduction assay and converted to absolute N ecosystem input by estimates...... of conversion factors between acetylene reduction and 15N incorporation. One aim was to relate nitrogen fluxes and nitrogen pools to the mosaic of ecosystem types of different stability common in areas of soil frost movements. A second aim was to identify abiotic controls on N2-fixation by simultaneous...... measurements of temperature, light, and soil moisture. Nitrogen fixation rate was high with seasonal input estimated at 1.1 g N m2 on frostheaved sorted circles, which was higher than the total plant N content and exceeded estimated annual plant N uptake several-fold but was lower than the microbial N content...

Identification of QTL Associated with Nitrogen Uptake and Nitrogen Use Efficiency Using High Throughput Genotyped CSSLs in Rice (Oryza sativa L.

Directory of Open Access Journals (Sweden)

Yong Zhou

2017-07-01

Full Text Available Nitrogen (N availability is a major factor limiting crop growth and development. Identification of quantitative trait loci (QTL for N uptake (NUP and N use efficiency (NUE can provide useful information regarding the genetic basis of these traits and their associated effects on yield production. In this study, a set of high throughput genotyped chromosome segment substitution lines (CSSLs derived from a cross between recipient 9311 and donor Nipponbare were used to identify QTL for rice NUP and NUE. Using high throughput sequencing, each CSSL were genotyped and an ultra-high-quality physical map was constructed. A total of 13 QTL, seven for NUP and six for NUE, were identified in plants under hydroponic culture with all nutrients supplied in sufficient quantities. The proportion of phenotypic variation explained by these QTL for NUP and NUE ranged from 3.16–13.99% and 3.76–12.34%, respectively. We also identified several QTL for biomass yield (BY and grain yield (GY, which were responsible for 3.21–45.54% and 6.28–7.31%, respectively, of observed phenotypic variation. GY were significantly positively correlated with NUP and NUE, with NUP more closely correlated than NUE. Our results contribute information to NUP and NUE improvement in rice.

Identification and quantification of nitrogen nutrient deficiency in the activated sludge process using respirometry

NARCIS (Netherlands)

Ning, Z.; Patry, G.G.; Spanjers, H.

2000-01-01

Experimental protocols to identify and quantify nitrogen nutrient deficiency in the activated sludge process were developed and tested using respirometry. Respirometric experiments showed that when a nitrogen nutrient deficient sludge is exposed to ammonia nitrogen, the oxygen uptake rate (OUR) of

Brucella, nitrogen and virulence.

Science.gov (United States)

Ronneau, Severin; Moussa, Simon; Barbier, Thibault; Conde-Álvarez, Raquel; Zuniga-Ripa, Amaia; Moriyon, Ignacio; Letesson, Jean-Jacques

2016-08-01

The brucellae are α-Proteobacteria causing brucellosis, an important zoonosis. Although multiplying in endoplasmic reticulum-derived vacuoles, they cause no cell death, suggesting subtle but efficient use of host resources. Brucellae are amino-acid prototrophs able to grow with ammonium or use glutamate as the sole carbon-nitrogen source in vitro. They contain more than twice amino acid/peptide/polyamine uptake genes than the amino-acid auxotroph Legionella pneumophila, which multiplies in a similar vacuole, suggesting a different nutritional strategy. During these two last decades, many mutants of key actors in nitrogen metabolism (transporters, enzymes, regulators, etc.) have been described to be essential for full virulence of brucellae. Here, we review the genomic and experimental data on Brucella nitrogen metabolism and its connection with virulence. An analysis of various aspects of this metabolism (transport, assimilation, biosynthesis, catabolism, respiration and regulation) has highlighted differences and similarities in nitrogen metabolism with other α-Proteobacteria. Together, these data suggest that, during their intracellular life cycle, the brucellae use various nitrogen sources for biosynthesis, catabolism and respiration following a strategy that requires prototrophy and a tight regulation of nitrogen use.

Effect of irrigation and fertilization on the distribution and fate of nitrogen in greenhouse tomato (solanum lycopersicum l.)

International Nuclear Information System (INIS)

Wang, X.; Xing, Y.

2017-01-01

A greenhouse experiment using tomato (Solanum lycopersicum L., cv. 'Jinpeng 10') was conducted to investigate the fate and transport of nitrogen using different methods of irrigation and fertilization. Three treatments were designed with two irrigation methods (drip irrigation and furrow irrigation) and two fertilizer application methods (fertigation and conventional fertilization). Tomato fruit yield and biomass in the fertigation treatment were significantly higher than those in the conventional fertilization treatment. The highest total uptake of nitrogen by tomato was obtained with drip fertigation and increased significantly in the conventional fertilization and CK treatments. With an increase in nitrate uptake by the fruit, the uptake of the leaf nitrogen also increased in both years of the study. The distribution of the soil nitrate-N concentration tended to be symmetrical along the center of the emitter for drip irrigation and the furrows. The nitrate-N concentration in the CK treatment was 2.85-fold higher than that in the drip fertigation treatment. The proportion of nitrogen uptake of the total nitrogen input varied from 25.38% and 53.73% in two consecutive years, and the residual nitrogen in the fertigation treatment was 48.20% and 44.64% lower than that in the CK treatment in the same two respective years. (author)

Temporal and spatial variation of nitrogen transformations in a coniferous soil.

NARCIS (Netherlands)

Laverman, A.M.; Zoomer, H.R.; van Verseveld, H.W.; Verhoef, H.A.

2000-01-01

Forest soils show a great degree of temporal and spatial variation of nitrogen mineralization. The aim of the present study was to explain temporal variation in nitrate leaching from a nitrogen-saturated coniferous forest soil by potential nitrification, mineralization rates and nitrate uptake by

Forest fuel reduces the nitrogen load

International Nuclear Information System (INIS)

Lundborg, A.

1993-03-01

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.)

Carbon-nitrogen-water interactions: is model parsimony fruitful?

Science.gov (United States)

Puertes, Cristina; González-Sanchis, María; Lidón, Antonio; Bautista, Inmaculada; Lull, Cristina; Francés, Félix

2017-04-01

It is well known that carbon and nitrogen cycles are highly intertwined and both should be explained through the water balance. In fact, in water-controlled ecosystems nutrient deficit is related to this water scarcity. For this reason, the present study compares the capability of three models in reproducing the interaction between the carbon and nitrogen cycles and the water cycle. The models are BIOME-BGCMuSo, LEACHM and a simple carbon-nitrogen model coupled to the hydrological model TETIS. Biome-BGCMuSo and LEACHM are two widely used models that reproduce the carbon and nitrogen cycles adequately. However, their main limitation is that these models are quite complex and can be too detailed for watershed studies. On the contrary, the TETIS nutrient sub-model is a conceptual model with a vertical tank distribution over the active soil depth, dividing it in two layers. Only the input of the added litter and the losses due to soil respiration, denitrification, leaching and plant uptake are considered as external fluxes. Other fluxes have been neglected. The three models have been implemented in an experimental plot of a semi-arid catchment (La Hunde, East of Spain), mostly covered by holm oak (Quercus ilex). Plant transpiration, soil moisture and runoff have been monitored daily during nearly two years (26/10/2012 to 30/09/2014). For the same period, soil samples were collected every two months and taken to the lab in order to obtain the concentrations of dissolved organic carbon, microbial biomass carbon, ammonium and nitrate. In addition, between field trips soil samples were placed in PVC tubes with resin traps and were left incubating (in situ buried cores). Thus, mineralization and nitrification accumulated fluxes for two months, were obtained. The ammonium and nitrate leaching accumulated for two months were measured using ion-exchange resin cores. Soil respiration was also measured every field trip. Finally, water samples deriving from runoff, were collected

Nitrogen use efficiency evaluation of aerobic rice under field capacity water potential using 15N isotopic tracer technique

International Nuclear Information System (INIS)

Wahid, Ahmad Nazrul Abd; Rahim, Sahibin Abd; Rahim, Khairuddin Abdul; Harun, Abdul Rahim

2015-01-01

This study was carried out to evaluate the efficiency use of the nitrogen fertilizer on aerobic rice varieties MR219-4 and MR219-9 which were grown aerobically under field capacity water potential at the controlled environment area or shield house. Direct 15 N isotope tracer method was used in this study, whereby the 15 N isotope was utilized as a tracer for nitrogen nutrient uptake. 15 N isotope presence in the samples is determined by using emission spectrometer analysis and percentage of total nitrogen is determined by using Kjeldahl method. 15 N atom access value contained in the sample will be used in determining the effectiveness of the use of nitrogen in fertilizers through the specific calculation formulas. In this work, the data several data of nitrogen derived from fertilizer (Ndff), total nitrogen, nitrogen uptake and nitrogen use efficiency was obtained

Natural and anthropogenic nitrogen uptake by bloom-forming macroalgae

International Nuclear Information System (INIS)

Thornber, Carol S.; DiMilla, Peter; Nixon, Scott W.; McKinney, Richard A.

2008-01-01

The frequency and duration of macroalgal blooms have increased in many coastal waters over the past several decades. We used field surveys and laboratory culturing experiments to examine the nitrogen content and δ 15 N values of Ulva and Gracilaria, two bloom-forming algal genera in Narragansett Bay, RI (USA). The northern end of this bay is densely populated with large sewage treatment plant nitrogen inputs; the southern end is more lightly populated and opens to the Atlantic Ocean. Field-collected Ulva varied in δ 15 N among sites, but with two exceptions had δ 15 N above 10 per mille , reflecting a significant component of heavy anthropogenic N. This variation was not correlated with a north-south gradient. Both Ulva and Gracilaria cultured in water from across Narragansett Bay also had high signals (δ 15 N = ∼14-17 per mille and 8-12 per mille , respectively). These results indicate that inputs of anthropogenic N can have far-reaching impacts throughout estuaries

Natural and anthropogenic nitrogen uptake by bloom-forming macroalgae

Energy Technology Data Exchange (ETDEWEB)

Thornber, Carol S. [Department of Biological Sciences, 100 Flagg Road, University of Rhode Island, Kingston, RI 02881 (United States)], E-mail: thornber@uri.edu; DiMilla, Peter; Nixon, Scott W. [Graduate School of Oceanography, University of Rhode Island, South Ferry Road, Narragansett, RI 02881 (United States); McKinney, Richard A. [US Environmental Protection Agency, Atlantic Ecology Division, 27 Tarzwell Drive, Narragansett, RI 02882 (United States)

2008-02-15

The frequency and duration of macroalgal blooms have increased in many coastal waters over the past several decades. We used field surveys and laboratory culturing experiments to examine the nitrogen content and {delta}{sup 15}N values of Ulva and Gracilaria, two bloom-forming algal genera in Narragansett Bay, RI (USA). The northern end of this bay is densely populated with large sewage treatment plant nitrogen inputs; the southern end is more lightly populated and opens to the Atlantic Ocean. Field-collected Ulva varied in {delta}{sup 15}N among sites, but with two exceptions had {delta}{sup 15}N above 10 per mille , reflecting a significant component of heavy anthropogenic N. This variation was not correlated with a north-south gradient. Both Ulva and Gracilaria cultured in water from across Narragansett Bay also had high signals ({delta}{sup 15}N = {approx}14-17 per mille and 8-12 per mille , respectively). These results indicate that inputs of anthropogenic N can have far-reaching impacts throughout estuaries.

Natural and anthropogenic nitrogen uptake by bloom-forming macroalgae.

Science.gov (United States)

Thornber, Carol S; DiMilla, Peter; Nixon, Scott W; McKinney, Richard A

2008-02-01

The frequency and duration of macroalgal blooms have increased in many coastal waters over the past several decades. We used field surveys and laboratory culturing experiments to examine the nitrogen content and delta(15)N values of Ulva and Gracilaria, two bloom-forming algal genera in Narragansett Bay, RI (USA). The northern end of this bay is densely populated with large sewage treatment plant nitrogen inputs; the southern end is more lightly populated and opens to the Atlantic Ocean. Field-collected Ulva varied in delta(15)N among sites, but with two exceptions had delta(15)N above 10 per thousand, reflecting a significant component of heavy anthropogenic N. This variation was not correlated with a north-south gradient. Both Ulva and Gracilaria cultured in water from across Narragansett Bay also had high signals (delta(15)N= approximately 14-17 per thousand and 8-12 per thousand, respectively). These results indicate that inputs of anthropogenic N can have far-reaching impacts throughout estuaries.

Nitrogen Uptake in Soils under Different Water Table Depths ...

African Journals Online (AJOL)

A mathematical model was used to examine the interactions of NH4 + transport to rice roots, as well as to calculate root length densities required to relate N uptake to concentrations of NH4 + in solution around the rooting medium for three water treatments: water table 30 cm below the surface, 15 cm below the surface and ...

Nutrient Uptake and Metabolism Along a Large Scale Tropical Physical-Chemical Gradient

Science.gov (United States)

Tromboni, F.; Neres-Lima, V.; Saltarelli, W. A.; Miwa, A. C. P.; Cunha, D. G. F.

2016-12-01

Nutrient spiraling is a whole-system approach for estimating nutrient uptake that can be used to assess aquatic ecosystems' responses to environmental change and anthropogenic impacts. Historically research on nutrient dynamic uptake in streams has focused on single nutrient dynamics and only rarely the stoichiometric uptake has been considered and linked to carbon metabolism driven by autotrophic and heterotrophic production. We investigated the relationship between uptake of phosphate (PO43-), nitrate (NO3-) ammonium (NH4+) and total dissolve nitrogen (DIN)/ PO43-; and gross primary production (GPP), respiration (R), and net ecosystem productivity (NEP) in six relatively pristine streams with differences regarding canopy cover and physical characteristics, located in a large scale gradient from tropical Atlantic Forest to an Atlantic forest/Cerrado (Brazilian Savanna) transition. We carried out whole stream instantaneous additions of PO43-, NO3- and NH4+ added to each stream in combination, using the TASCC (Tracer Additions for Spiraling Curve Characterization) method. Metabolism measurements were performed in the same streams right after uptake was measured, using one-station open channel method and re-aeration estimations for those sites. We found different background concentrations in the streams located in the Atlantic forest compared with the transition area with Cerrado. In general PO43- and NO3- uptake increased with the decreasing of canopy cover, while a positive relation with background concentration better explained NH4+uptake. DIN/PO43- uptake increased with increasing R and NEP. Little work on functional characteristics of pristine streams has been conducted in this region and this work provides an initial characterization on nitrogen and phosphorus dynamics as well as their stoichiometric uptake in streams.

CO{sub 2} removal potential of carbons prepared by co-pyrolysis of sugar and nitrogen containing compounds

Energy Technology Data Exchange (ETDEWEB)

Arenillas, A.; Drage, T.C.; Smith, K.; Snape, C.E. [University of Nottingham, Fuel Science Group, School of Chemical, Environmental and Mining Engineering, University Park, Nottingham NG7 2RD (United Kingdom)

2005-08-15

The nitrogen enrichment of active carbons is reported to be effective in enhancing the specific adsorbate-adsorbent interactions for CO{sub 2}. In this work, nitrogen-enriched carbons were prepared by co-pyrolysis of sugar and a series of nitrogen compounds with different nitrogen functionalities. The results show that although the amount of nitrogen incorporated to the final adsorbent is important, the N-functionality seems to be more relevant for increasing CO{sub 2} uptake. Thus, the adsorbent obtained from urea co-pyrolysis presents the highest nitrogen content but the lowest CO{sub 2} adsorption capacity. However, the adsorbent obtained from carbazole co-pyrolysis, despite the lower amount of N incorporated, shows high CO{sub 2} uptake, up to 9wt.%, probably because the presence of more basic functionalities as determined by XPS analysis.

Nitrogen saturation in stream ecosystems.

Science.gov (United States)

Earl, Stevan R; Valett, H Maurice; Webster, Jackson R

2006-12-01

The concept of nitrogen (N) saturation has organized the assessment of N loading in terrestrial ecosystems. Here we extend the concept to lotic ecosystems by coupling Michaelis-Menten kinetics and nutrient spiraling. We propose a series of saturation response types, which may be used to characterize the proximity of streams to N saturation. We conducted a series of short-term N releases using a tracer (15NO3-N) to measure uptake. Experiments were conducted in streams spanning a gradient of background N concentration. Uptake increased in four of six streams as NO3-N was incrementally elevated, indicating that these streams were not saturated. Uptake generally corresponded to Michaelis-Menten kinetics but deviated from the model in two streams where some other growth-critical factor may have been limiting. Proximity to saturation was correlated to background N concentration but was better predicted by the ratio of dissolved inorganic N (DIN) to soluble reactive phosphorus (SRP), suggesting phosphorus limitation in several high-N streams. Uptake velocity, a reflection of uptake efficiency, declined nonlinearly with increasing N amendment in all streams. At the same time, uptake velocity was highest in the low-N streams. Our conceptual model of N transport, uptake, and uptake efficiency suggests that, while streams may be active sites of N uptake on the landscape, N saturation contributes to nonlinear changes in stream N dynamics that correspond to decreased uptake efficiency.

The cyanobacterium Mastigocladus fulfills the nitrogen demand of a terrestrial hot spring microbial mat.

Science.gov (United States)

Estrella Alcamán, María; Fernandez, Camila; Delgado, Antonio; Bergman, Birgitta; Díez, Beatriz

2015-10-01

Cyanobacteria from Subsection V (Stigonematales) are important components of microbial mats in non-acidic terrestrial hot springs. Despite their diazotrophic nature (N2 fixers), their impact on the nitrogen cycle in such extreme ecosystems remains unknown. Here, we surveyed the identity and activity of diazotrophic cyanobacteria in the neutral hot spring of Porcelana (Northern Patagonia, Chile) during 2009 and 2011-2013. We used 16S rRNA and the nifH gene to analyze the distribution and diversity of diazotrophic cyanobacteria. Our results demonstrate the dominance of the heterocystous genus Mastigocladus (Stigonematales) along the entire temperature gradient of the hot spring (69-38 °C). In situ nitrogenase activity (acetylene reduction), nitrogen fixation rates (cellular uptake of (15)N2) and nifH transcription levels in the microbial mats showed that nitrogen fixation and nifH mRNA expression were light-dependent. Nitrogen fixation activities were detected at temperatures ranging from 58 °C to 46 °C, with maximum daily rates of 600 nmol C2H4 cm(-2) per day and 94.1 nmol N cm(-2) per day. These activity patterns strongly suggest a heterocystous cyanobacterial origin and reveal a correlation between nitrogenase activity and nifH gene expression during diurnal cycles in thermal microbial mats. N and C fixation in the mats contributed ~3 g N m(-2) per year and 27 g C m(-2) per year, suggesting that these vital demands are fully met by the diazotrophic and photoautotrophic capacities of the cyanobacteria in the Porcelana hot spring.

Nitrogen-doped carbon monolith for alkaline supercapacitors and understanding nitrogen-induced redox transitions.

Science.gov (United States)

Wang, Da-Wei; Li, Feng; Yin, Li-Chang; Lu, Xu; Chen, Zhi-Gang; Gentle, Ian R; Lu, Gao Qing; Cheng, Hui-Ming

2012-04-23

A nitrogen-doped porous carbon monolith was synthesized as a pseudo-capacitive electrode for use in alkaline supercapacitors. Ammonia-assisted carbonization was used to dope the surface with nitrogen heteroatoms in a way that replaced carbon atoms but kept the oxygen content constant. Ammonia treatment expanded the micropore size-distributions and increased the specific surface area from 383 m(2) g(-1) to 679 m(2) g(-1). The nitrogen-containing porous carbon material showed a higher capacitance (246 F g(-1)) in comparison with the nitrogen-free one (186 F g(-1)). Ex situ electrochemical spectroscopy was used to investigate the evolution of the nitrogen-containing functional groups on the surface of the N-doped carbon electrodes in a three-electrode cell. In addition, first-principles calculations were explored regarding the electronic structures of different nitrogen groups to determine their relative redox potentials. We proposed possible redox reaction pathways based on the calculated redox affinity of different groups and surface analysis, which involved the reversible attachment/detachment of hydroxy groups between pyridone and pyridine. The oxidation of nitrogen atoms in pyridine was also suggested as a possible reaction pathway. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dependence of intestinal amino acid uptake on dietary protein or amino acid levels

International Nuclear Information System (INIS)

Karasov, W.H.; Solberg, D.H.; Diamond, J.M.

1987-01-01

To understand how intestinal amino acid (AA) transport is regulated by dietary substrate levels, the authors measured uptake of seven radioactively-labelled AAs and glucose across the jejunal brush-border membrane of mice kept on one of three isocaloric rations differing in nitrogen content. In the high-protein ration, uptake increased by 77-81% for the nonessential, less toxic AAs, proline, and aspartate but only by 32-61% for the more toxic essential AAs tested. In the nitrogen-deficient ration, uptake decreased for the nonessential aspartate and proline but stayed constant or increased for essential AAs and for the nonessential alanine. These patterns imply independent regulation of the intestine's various AA transporters. With decreasing dietary AA (or protein), the imino acid and acidic AA private transporters are repressed, while activities of the basic AA transporter and the neutral AA public transporter decrease to an asymptote or else go through a minimum. These regulatory patterns can be understood as a compromise among conflicting constraints imposed by protein's multiple roles as a source of calories, nitrogen, and essential AAs and by the toxicity of essential AAs at high concentrations

Carbon-nitrogen feedbacks in the UVic ESCM

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R. Wania

2012-09-01

Full Text Available A representation of the terrestrial nitrogen cycle is introduced into the UVic Earth System Climate Model (UVic ESCM. The UVic ESCM now contains five terrestrial carbon pools and seven terrestrial nitrogen pools: soil, litter, leaves, stem and roots for both elements and ammonium and nitrate in the soil for nitrogen. Nitrogen cycles through plant tissue, litter, soil and the mineral pools before being taken up again by the plant. Biological N₂ fixation and nitrogen deposition represent external inputs to the plant-soil system while losses occur via leaching. Simulated carbon and nitrogen pools and fluxes are in the range of other models and observations. Gross primary production (GPP for the 1990s in the CN-coupled version is 129.6 Pg C a⁻¹ and net C uptake is 0.83 Pg C a⁻¹, whereas the C-only version results in a GPP of 133.1 Pg C a⁻¹ and a net C uptake of 1.57 Pg C a⁻¹. At the end of a transient experiment for the years 1800–1999, where radiative forcing is held constant but CO₂ fertilisation for vegetation is permitted to occur, the CN-coupled version shows an enhanced net C uptake of 1.05 Pg C a⁻¹, whereas in the experiment where CO₂ is held constant and temperature is transient the land turns into a C source of 0.60 Pg C a⁻¹ by the 1990s. The arithmetic sum of the temperature and CO₂ effects is 0.45 Pg C a⁻¹, 0.38 Pg C a⁻¹ lower than seen in the fully forced model, suggesting a strong nonlinearity in the CN-coupled version. Anthropogenic N deposition has a positive effect on Net Ecosystem Production of 0.35 Pg C a⁻¹. Overall, the UVic CN-coupled version shows similar characteristics to other CN-coupled Earth System Models, as measured by net C balance and sensitivity to changes in climate, CO₂ and temperature.

Kinetic Uptake Studies of Powdered Materials in Solution

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Mohamed H. Mohamed

2015-06-01

Full Text Available Challenges exist for the study of time dependent sorption processes for heterogeneous systems, especially in the case of dispersed nanomaterials in solvents or solutions because they are not well suited to conventional batch kinetic experiments. In this study, a comparison of batch versus a one-pot setup in two variable configurations was evaluated for the study of uptake kinetics in heterogeneous (solid/solution systems: (i conventional batch method; (ii one-pot system with dispersed adsorbent in solution with a semi-permeable barrier (filter paper or dialysis tubing for in situ sampling; and (iii one-pot system with an adsorbent confined in a semi-permeable barrier (dialysis tubing or filter paper barrier with ex situ sampling. The sorbent systems evaluated herein include several cyclodextrin-based polyurethane materials with two types of phenolic dyes: p-nitrophenol and phenolphthalein. The one-pot kinetics method with in situ (Method ii or ex situ (Method iii sampling described herein offers significant advantages for the study of heterogeneous sorption kinetics of highly dispersed sorbent materials with particles sizes across a range of dimensions from the micron to nanometer scale. The method described herein will contribute positively to the development of advanced studies for heterogeneous sorption processes where an assessment of the relative uptake properties is required at different experimental conditions. The results of this study will be advantageous for the study of nanomaterials with significant benefits over batch kinetic studies for a wide range of heterogeneous sorption processes.

Effect of organic matter application and water regimes on the transformation of fertilizer nitrogen in a Philippine soil

International Nuclear Information System (INIS)

Yoshida, Tomio; Padre, B.C. Jr.

1975-01-01

Greenhouse experiments using the tracer technique showed that about 20 per cent of the fertilizer nitrogen added as basal to the Maahas clay soil was immobilized in submerged soils to which no organic material was added. The addition of organic matter to the soil increases the amount of nitrogen immobilized and the magnitude depends on the carbon to nitrogen ratio of the materials added. More fertilizer nitrogen was immobilized in the soils under upland and alternate wet-and-dry conditions than under submerged soil conditions. The uptake of fertilizer nitrogen by rice plants growing under submerged soil conditions ceased at the vegetative stage of growth because only a small amount of available nitrogen remains in the soil at this time, but the rice plant continued to absorb gradually untagged nitrogen from the soil throughout the reproductive stages of growth. Losses of fertilizer nitrogen were great under the alternate wet-and-dry conditions (submerged-upland). The loss of nitrogen from the soil-plant system was reduced by the addition of rice straw, which also reduced the uptake of fertilizer nitrogen but not the total dry matter production under the experimental conditions. Fertilizer nitrogen immobilized during the first crop remained mostly in the soil throughout the full period of the second crop. The total nitrogen uptake by rice plants was not affected by the soil moisture tension under the upland conditions used in the study but the movement of nitrogen from the leaves to the panicles during the reproductive stage seemed to decrease as the soil moisture tension increased. (auth.)

Temporal and spatial variation of nitrogen transformations in a coniferous forest soils.

NARCIS (Netherlands)

Laverman, A.M.; Zoomer, H.R.; van Verseveld, H.W.; Verhoef, H.A.

2000-01-01

Forest soils show a great degree of temporal and spatial variation of nitrogen mineralization. The aim of the present study was to explain temporal variation in nitrate leaching from a nitrogen-saturated coniferous forest soil by potential nitrification, mineralization rates and nitrate uptake by

Fluxes of oxidised and reduced nitrogen above a mixed coniferous forest exposed to various nitrogen emission sources

International Nuclear Information System (INIS)

Neirynck, J.; Kowalski, A.S.; Carrara, A.; Genouw, G.; Berghmans, P.; Ceulemans, R.

2007-01-01

Concentrations of nitrogen gases (NH 3 , NO 2 , NO, HONO and HNO 3 ) and particles (pNH 4 and pNO 3 ) were measured over a mixed coniferous forest impacted by high nitrogen loads. Nitrogen dioxide (NO 2 ) represented the main nitrogen form, followed by nitric oxide (NO) and ammonia (NH 3 ). A combination of gradient method (NH 3 and NO x ) and resistance modelling techniques (HNO 3 , HONO, pNH 4 and pNO 3 ) was used to calculate dry deposition of nitrogen compounds. Net flux of NH 3 amounted to -64 ng N m -2 s -1 over the measuring period. Net fluxes of NO x were upward (8.5 ng N m -2 s -1 ) with highest emission in the morning. Fluxes of other gases or aerosols substantially contributed to dry deposition. Total nitrogen deposition was estimated at -48 kg N ha -1 yr -1 and consisted for almost 80% of NH x . Comparison of throughfall nitrogen with total deposition suggested substantial uptake of reduced N (±15 kg N ha -1 yr -1 ) within the canopy. - Reduced nitrogen was found to be the main contributor to total deposition which was predominantly governed by dry deposition

Occurrence and distribution of nitrogen-scavenging bacteria in marine environment

OpenAIRE

Sugahara, Isao; Kimura, Toshio; Hayashi, Koichiro

1987-01-01

The occurrence and distribution nitrogen-scavenging bacteria in the water of coastal and oceanic of Japan were studied during the Seisui-Maru cruises from 1986 to 1987. Nitroben-scavenging bacteria in the water usually occurred at the level of 10-104 cfu/ml.This value was almost comparable to that of aerobic heterotrophic bacteria. It seems that nitrogen-scavenging bacteria play an important role in the efficient uptake of low levels of nitrogenous compounds in marine enviroment.

Nitrogen cycling in a turbid, tidal estuary

NARCIS (Netherlands)

Andersson, M.G.I.

2007-01-01

In this thesis I investigated nitrification, dissolved inorganic and organic nitrogen uptake, and the relative importance of nitrification and ammonium assimilation. I have also investigated exchange with marshes and sediments. Nitrification, oxidation of ammonium to nitrate is the first step for

Effect of different rates of nitrogen fertilizer on durum wheat (Triticum ...

African Journals Online (AJOL)

Dr Asefa

2012-05-03

May 3, 2012 ... The result showed that nitrogen rates and cultivars had significant effect on yield, yield related traits, nitrogen uptake ... cooking quality [8]. Durum wheat grain protein functionality can be influenced by N fertilization, particularly in the varieties of relatively with less gluten strength [9]. Information on the quality ...

Winter cover crops as a best management practice for reducing nitrogen leaching

Science.gov (United States)

Ritter, W. F.; Scarborough, R. W.; Chirnside, A. E. M.

1998-10-01

The role of rye as a winter cover crop to reduce nitrate leaching was investigated over a three-year period on a loamy sand soil. A cover crop was planted after corn in the early fall and killed in late March or early April the following spring. No-tillage and conventional tillage systems were compared on large plots with irrigated corn. A replicated randomized block design experiment was conducted on small plots to evaluate a rye cover crop under no-tillage and conventional tillage and with commercial fertilizer, poultry manure and composted poultry manure as nitrogen fertilizer sources. Nitrogen uptake by the cover crop along with nitrate concentrations in groundwater and the soil profile (0-150 cm) were measured on the large plots. Soil nitrate concentrations and nitrogen uptake by the cover crop were measured on the small plots. There was no significant difference in nitrate concentrations in the groundwater or soil profile with and without a cover crop in either no-tillage or conventional tillage. Annual amounts of nitrate-N leached to the water-table varied from 136.0 to 190.1 kg/ha in 1989 and from 82.4 to 116.2 kg/ha in 1991. Nitrate leaching rates were somewhat lower with a cover crop in 1989, but not in 1990. There was no statistically significant difference in corn grain yields between the cover crop and non-cover crop treatments. The planting date and adequate rainfall are very important in maximizing nitrogen uptake in the fall with a rye cover crop. On the Delmarva Peninsula, the cover crop should probably be planted by October 1 to maximize nitrogen uptake rates in the fall. On loamy sand soils, rye winter cover crops cannot be counted on as a best management practice for reducing nitrate leaching in the Mid-Atlantic states.

Nitrogen fate and Transport in Diverse Agricultural Watersheds

Science.gov (United States)

Essaid, H.; McCarthy, K. A.; Baker, N. T.

2010-12-01

Nitrogen mass budgets have been estimated for ten agricultural watersheds located in a range of hydrologic settings in order to understand the factors controlling the fate of nitrogen applied at the surface. The watersheds, study areas of the Agricultural Chemical Sources, Transport and Fate study of the U.S. Geological Survey National Water Quality Assessment Program, are located in Indiana (IN), Iowa (IA), Maryland (MD), Nebraska (NE), Mississippi (MS) and Washington (WA). They range in size from 7 to 1254 km2, with four of the watersheds nested within larger watersheds. Surface water outflow (normalized to watershed area) ranged from 4 to 83 cm/yr. Crops planted include corn, soybean, small grains, rice, cotton, orchards and vegetables. “Surplus nitrogen” was determined for each watershed by subtracting estimates of crop uptake and volatilization from estimates of nitrogen input from atmospheric deposition, plant fixation, and fertilizer and manure applications for the period from 1987 to 2004. This surplus nitrogen is transported though the watershed via surface and subsurface flow paths, while simultaneously undergoing transformations (such as denitrification and in-stream processing) that result in less export of nitrogen from the watershed. Surface-water discharge and concentration data were used to estimate the export of nitrogen from the watersheds (groundwater outflow from the watersheds was minimal). Subtracting nitrogen export from surplus nitrogen provides an estimate of the net amount of nitrogen removal occurring during internal watershed transport. Watershed average nitrogen surplus ranged from 6 to 49 kg-N/ha. The more permeable and/or greater water flux watersheds (MD, NE, and WA) tended to have larger surplus nitrogen, possibly due to less crop uptake caused by greater leaching and runoff of nitrogen. Almost all of the surplus nitrogen in the low permeability (MS) and tile drained watersheds (IA, IN) was exported from the watershed with

The fate of fertilizer nitrogen in winter wheat under different water and nitrogen levels

International Nuclear Information System (INIS)

Li Shijuan; Zhou Dianxi; Lan Linwang

2002-01-01

N uptake and the fate of fertilizer N were studied in the field under different water and nitrogen levels with 15 N technique. Results showed that (1) the total N uptake of economical N treatment under saving irrigation was higher than that under conventional irrigation. Under saving irrigation the total N uptake of conventional N was higher than that of economical N treatment, yet the NHI decreased; (2) compared with saving irrigation, the N loss of conventional irrigation increased and NUE and soil residue decreased. On the same water condition the NUE and soil residue of conventional N treatment was lower than that of economical treatment, and N loss increased; (3) for the same fertilizer amount, the loss of N applied all as basal fertilizer is lower than that of part as basal and part as top-dressing treatment

OMI and Ground-Based In-Situ Tropospheric Nitrogen Dioxide Observations over Several Important European Cities during 2005–2014

Directory of Open Access Journals (Sweden)

Spiru Paraschiv

2017-11-01

Full Text Available In this work we present the evolution of tropospheric nitrogen dioxide (NO2 content over several important European cities during 2005–2014 using space observations and ground-based in-situ measurements. The NO2 content was derived using the daily observations provided by the Ozone Monitoring Instrument (OMI, while the NO2 volume mixing ratio measurements were obtained from the European Environment Agency (EEA air quality monitoring stations database. The European cities selected are: Athens (37.98° N, 23.72° E, Berlin (52.51° N, 13.41° E, Bucharest (44.43° N, 26.10° E, Madrid (40.38° N, 3.71° W, Lisbon (38.71° N, 9.13° W, Paris (48.85° N, 2.35° E, Rome (41.9° N, 12.50° E, and Rotterdam (51.91° N, 4.46° E. We show that OMI NO2 tropospheric column data can be used to assess the evolution of NO2 over important European cities. According to the statistical analysis, using the seasonal variation, we found good correlations (R > 0.50 between OMI and ground-based in-situ observations for all of the cities presented in this work. Highest correlation coefficients (R > 0.80 between ground-based monitoring stations and OMI observations were calculated for the cities of Berlin, Madrid, and Rome. Both types of observations, in-situ and remote sensing, show an NO2 negative trend for all of locations presented in this study.

Effect of Nitrogen, Phosphorus and Potassium on the Dynamics of Synthesis of Nucleic Acids and Proteins in the Different Phases of Wheat Development

Energy Technology Data Exchange (ETDEWEB)

Martinovic, B.; Grujic-Injac, B.; Jelenic, Dj. [Institute for the Application of Nuclear Energy in Agriculture, Veterinary Medicine and Forestry, Belgrade (Yugoslavia)

1968-07-01

The influence of different nitrogen, phosphorus and potassium levels on the dynamics of RNA synthesis and raw proteins, as well as the uptake of phosphorus in the different phases of wheat development, were studied by applying radioactive phosphorus {sup 32}P . The rate of the uptake of phosphorus is proportional to its concentration in the nutrient supply in all phases of wheat development, in spite of the fact that the uptake of phosphorus during vegetation decreases with the plant's maturity. The influence of nitrogen on the uptake of phosphorus is inversely proportional to the concentration of nitrogen in the nutrient, while the influence of potassium depends on the relation of the amounts of nitrogen and phosphorus. The increased levels of nitrogen and phosphorus are directly proportional to the increase of RNA synthesis, and conversely the decrease of these levels decreases the RNA synthesis. The RNA synthesis decreases with the wheat's maturity during vegetation and is considerably greater in the first phase than in the later phases of the plant's development. Nitrogen and phosphorus have the greatest influence on protein synthesis; potassium has far less influence. These investigations show that the synthesis of nucleic acids and the building up of phosphorus in the RNA-fraction is directly proportional to the concentration of nitrogen in the nutrient supply, even though the uptake of phosphorus by wheat is not proportional to the increased nitrogen levels. Investigations now being carried out provide further explanations concerning the mutual relationship of some forms of RNA of the cells and the amino acids in the synthesis of certain protein fractions of wheat under the influence of different levels of nitrogen, phosphorus and potassium. (author)

Nitrogen Balance During Sweet Sorghum Cropping Cycle as Affected by Irrigation and Fertilization Rate

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Stella Lovelli

Full Text Available A two-year trial was carried out on sweet sorghum, grown in semi-arid environments of southern Europe. The trial was aimed to monitor the main components of the crop N-balance under different irrigation regimes and nitrogen fertilization rates, in factorial combination. A rainfed condition (only one watering soon after sowing was compared with a deficit irrigation regime and a full irrigation treatment (50 and 100% restoration of total crop water consumption, respectively. Crop nitrogen uptake always showed to be the highest N-balance components and was included in the range of 125-194 kg ha-1 during 1997-1998, with respect to the total shoot biomass, according to the nitrogen fertilization rate; consequently, it significantly reduced both nitrogen concentration in the soil solution and the total nitrogen loss due to drainage. Nitrogen concentration in the drainage water didn’t result to be strictly dependent on the rate of fertiliser applied but on the actual soil nitrogen content; the maximum registered value of total nitrogen lost by leaching was 1.9 kg ha-1. Differently, total nitrogen loss due to volatilisation was proportional to the amount of fertilizer applied; irrigation favourably reduced this kind of loss. The limited amount of Nvolatilisation loss was probably due to the neutral pH soil conditions; as an order of magnitude, referring to the highest fertilized but rainfed treatment, the utmost N-volatilisation loss was equal to 5.5 Kg ha-1, as an average over the three years, that is to say less than the 5% of the fertilization rate. A fertilisation rate of 120 Kg ha-1 of nitrogen, together with water application, generally produced a balance between crop N-uptake and total N-loss due to volatilisation and drainage (only the stalk biomass was considered in this calculation. Lower rates of fertilizing nitrogen, indeed, determined a depletion in the soil nitrogen content because of the high crop biomass and the strong N-uptake by the

Nitrogen Balance During Sweet Sorghum Cropping Cycle as Affected by Irrigation and Fertilization Rate

Directory of Open Access Journals (Sweden)

Michele Perniola

2011-02-01

Full Text Available A two-year trial was carried out on sweet sorghum, grown in semi-arid environments of southern Europe. The trial was aimed to monitor the main components of the crop N-balance under different irrigation regimes and nitrogen fertilization rates, in factorial combination. A rainfed condition (only one watering soon after sowing was compared with a deficit irrigation regime and a full irrigation treatment (50 and 100% restoration of total crop water consumption, respectively. Crop nitrogen uptake always showed to be the highest N-balance components and was included in the range of 125-194 kg ha-1 during 1997-1998, with respect to the total shoot biomass, according to the nitrogen fertilization rate; consequently, it significantly reduced both nitrogen concentration in the soil solution and the total nitrogen loss due to drainage. Nitrogen concentration in the drainage water didn’t result to be strictly dependent on the rate of fertiliser applied but on the actual soil nitrogen content; the maximum registered value of total nitrogen lost by leaching was 1.9 kg ha-1. Differently, total nitrogen loss due to volatilisation was proportional to the amount of fertilizer applied; irrigation favourably reduced this kind of loss. The limited amount of Nvolatilisation loss was probably due to the neutral pH soil conditions; as an order of magnitude, referring to the highest fertilized but rainfed treatment, the utmost N-volatilisation loss was equal to 5.5 Kg ha-1, as an average over the three years, that is to say less than the 5% of the fertilization rate. A fertilisation rate of 120 Kg ha-1 of nitrogen, together with water application, generally produced a balance between crop N-uptake and total N-loss due to volatilisation and drainage (only the stalk biomass was considered in this calculation. Lower rates of fertilizing nitrogen, indeed, determined a depletion in the soil nitrogen content because of the high crop biomass and the strong N-uptake by the

Soil Microbial Communities and Gas Dynamics Contribute to Arbuscular Mycorrhizal Nitrogen Uptake and Transfer to Plants

Science.gov (United States)

Hestrin, R.; Harrison, M. J.; Lehmann, J.

2016-12-01

Arbuscular mycorrhizal fungi (AMF) associate with most terrestrial plants and influence ecosystem ecology and biogeochemistry. There is evidence that AMF play a role in soil nitrogen cycling, in part by taking up nitrogen and transferring it to plants. However, many aspects of this process are poorly understood, including the factors that control fungal access to nitrogen stored in soil organic matter. In this study, we used stable isotopes and root exclusion to track nitrogen movement from organic matter into AMF and host plants. AMF significantly increased total plant biomass and nitrogen content, but both AMF and other soil microbes seemed to compete with plants for nitrogen. Surprisingly, gaseous nitrogen species also contributed significantly to plant nitrogen content under alkaline soil conditions. Our current experiments investigate whether free-living microbial communities that have evolved under a soil nitrogen gradient influence AMF access to soil organic nitrogen and subsequent nitrogen transfer to plants. This research links interactions between plants, mycorrhizal symbionts, and free-living microbes with terrestrial carbon and nitrogen dynamics.

Nitrogen uptake and assimilation by two families of loblolly pine under simulated field conditions in the greenhouse

International Nuclear Information System (INIS)

White, T.A.

1989-01-01

While significant success has been achieved in pine tree improvement, comparatively little is known about the physiological strategies employed by superior genotypes. The central hypothesis of this research was that dissimilarities of two families of loblolly pine (Pinus taeda L.) in absorption, use, and allocation of N and C during and after periods of N stress explain differences in productivity. One group of trees was exposed to NH 4 + -N (100:0 experiment) for 84 d while a second group was grown with a 70% NH 4 + : 30% NO 3 - -N solution (70:30 experiment). Ammonium-N was labelled with 15 N. Half of the seedlings had restricted N supplies from 28 d to 70 d. Results were compared to the unstressed half of each group. Nitrogen stress resulted in significantly lower biomass production and N uptake in both families in the 70:30 experiment. The superior family recovered these losses 14 d after the N stress was removed. No difference in biomass existed in either family following N stress in the 100:0 experiment

Nitrogen effects on mobility and plant uptake of heavy metals in sewage sludge applied to soil columns

Energy Technology Data Exchange (ETDEWEB)

Giordano, P.M.; Mortvedt, J.J.

1976-01-01

Cation movement in soil under leaching conditions has been associated with N fertilization. Therefore, this study was conducted to determine whether the mobility of some heavy metals applied in the inorganic form or in sewage sludge is enhanced in the presence of various sources of N. Columns of heavy metal-amended soil in plastic well casings were cropped with tall fescue (Festuca arundinacea Schreb.) and leached three times with deionized H/sub 2/O. Heavy metal concentrations above check values were not detected in leachates from any column. Mobility of the heavy metals from the inorganic sources was slightly greater than that from the sewage sludge. Nitrogen fertilization did not affect the downward movement of Zn, Cd, Cr, Pb, or Ni in soil but enhanced uptake of these metals by fescue because of increased growth. These results suggest that heavy metal contamination of ground water is not likely in heavy textured soils when sewage sludge applications are accompanied by N fertilization, at least for short periods of time. 11 references, 1 figure, 4 tables.

Assessment of free-living nitrogen fixing microorganisms for commercial nitrogen fixation. [economic analysis of ammonia production

Science.gov (United States)

Stokes, B. O.; Wallace, C. J.

1978-01-01

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.

Nitrogen-15 uptake by whole plants and root callus cultures of inbred maize lines and their F1 hybrids

International Nuclear Information System (INIS)

Mladenova, Y.; Karadimova, M.

1981-01-01

The uptake of nitrogen-15 by 3 maize genotypes was investigated. Comparative analysis of N15 assimilation and distribution in the organs of intact plants of two self-pollinated lines and their F1 hybrid and also in a callus tissue of roots of the same genotypes was made. From the results the conclusion is drawn that the N-use efficiency of the female line is higher than that of the male line both in intact plants and callus tissues from roots. This fact indicates that the N-use efficiency is determined not only by the functions of the cells in the shoots, suggesting the participation of the photosynthetic carboxylases but also by the functions of cells without a photosynthesizing apparatus. The N-use efficiency in the F1 hybrid manifests ''heterosis'', in spite of the intact plants or root callus tissues are being studied. (author)

Response of Cotton to Irrigation Methods and Nitrogen Fertilization: Yield Components, Water-Use Efficiency, Nitrogen Uptake, and Recovery

International Nuclear Information System (INIS)

Janat, M.

2009-01-01

Efficient crop use of nitrogen (N) fertilizer is critical from economic and environmental viewpoints, especially under irrigated conditions. Cotton yield parameters, fiber quality, water- and N-use efficiency responses to N, and irrigation methods in northern Syria were evaluated. Field trials were conducted for two growing seasons on a Chromoxerertic Rhodoxeralf soil. Treatments consisted of drip fertigation, furrow irrigation, and five different rates of N fertilizer (50, 100, 150, 200, and 250 kg N /ha). Cotton was irrigated when soil moisture in the specified active root depth was 80% of the field capacity as indicated by the neutron probe. Seed cotton yield was higher than the national average (3,928 kg/ha) by at least 12% as compared to all treatments. Lint properties were not negatively affected by the irrigation method or N rates. Water savings under drip fertigation ranged between 25 and 50% of irrigation water relative to furrow irrigation. Crop water-use efficiencies of the drip-fertigated treatments were in most cases 100% higher than those of the corresponding furrow-irrigated treatments. The highest water demand was during the fruit-setting growth stage. It was also concluded that under drip fertigation, 100 -150 N kg/ha was adequate and comparable with the highest N rates tested under furrow irrigation regarding lint yield, N uptake, and recovery. Based on cotton seed yield and weight of stems, the overall amount of N removed from the field for the drip-fertigated treatments ranged between 101-118 kg and 116-188 N/ha for 2001 and 2002, respectively. The N removal ranged between 94-113 and 111-144 kg N/ha for the furrow-irrigated treatments for 2001 and 2002, respectively. (author)

Intraclade heterogeneity in nitrogen utilization by marine prokaryotes revealed using stable isotope probing coupled with tag sequencing (Tag-SIP

Directory of Open Access Journals (Sweden)

Michael Morando

2016-12-01

Full Text Available Nitrogen can greatly influence the structure and productivity of microbial communities through its relative availability and form. However, roles of specific organisms in the uptake of different nitrogen species remain poorly characterized. Most studies seeking to identify agents of assimilation have been correlative, indirectly linking activity measurements (e.g., nitrate uptake with the presence or absence of biological markers, particularly functional genes and their transcripts. Evidence is accumulating of previously underappreciated functional diversity in major microbial subpopulations, which may confer physiological advantages under certain environmental conditions leading to ecotype divergence. This microdiversity further complicates our view of genetic variation in environmental samples requiring the development of more targeted approaches. Here, next-generation tag sequencing was successfully coupled with stable isotope probing (Tag-SIP to assess the ability of individual phylotypes to assimilate a particular N source. Our results provide the first direct evidence of nitrate utilization by organisms thought to lack the genes required for this process including the heterotrophic clades SAR11 and the Archaeal Marine Group II (MG-II. We also provide new direct evidence of in situ nitrate utilization by the cyanobacterium Prochlorococcus in support of recent findings. Furthermore, these results revealed widespread functional heterogeneity, i.e. different levels of N assimilation within clades, likely reflecting niche partitioning by ecotypes. The addition of nitrate utilization to ecosystem and ecosystem models by these globally dominant clades will likely improve the mechanistic accuracy of these models.

Long-term population dynamics and in situ physiology in activated sludge systems with enhanced biological phosphorus removal operated with and without nitrogen removal

DEFF Research Database (Denmark)

Lee, N.; Nielsen, P.H.; Aspegren, H.

2003-01-01

. However, we observed a lower correlation (0.9). The Actinobacteria were the only additional group of bacteria which showed a similar degree of correlation to the P content in activated sludge as the Rhodocyclus-related bacteria - but only for the system without nitrogen removal. Significant amounts (less...... of the Betaproteobacteria (part of them identified as Rhodocyclus-related bacteria) as well as the Actinobacteria were able to take up P-33(i), [H-3]-acetate and [H-3]-glucose under anaerobic-aerobic conditions. The contribution of anoxic P-33(i) uptake under alternating anaerobic-anoxic conditions was significantly lower...

The role of nitrogen uptake on the competition ability of three vineyard Saccharomyces cerevisiae strains.

Science.gov (United States)

Vendramini, Chiara; Beltran, Gemma; Nadai, Chiara; Giacomini, Alessio; Mas, Albert; Corich, Viviana

2017-10-03

Three vineyard strains of Saccharomyces cerevisiae, P301.4, P304.4 and P254.12, were assayed in comparison with a commercial industrial strain, QA23. The aim was to understand if nitrogen availability could influence strain competition ability during must fermentation. Pairwise-strain fermentations and co-fermentations with the simultaneous presence of the four strains were performed in synthetic musts at two nitrogen levels: control nitrogen condition (CNC) that assured the suitable assimilable nitrogen amount required by the yeast strains to complete the fermentation and low nitrogen condition (LNC) where nitrogen is present at very low level. Results suggested a strong involvement of nitrogen availability, as the frequency in must of the vineyard strains, respect to QA23, in LNC was always higher than that found in CNC. Moreover, in CNC only strain P304.4 reached the same strain frequency as QA23. P304.4 competition ability increased during the fermentation, indicating better performance when nitrogen availability was dropping down. P301.4 was the only strain sensitive to QA23 killer toxin. In CNC, when it was co-inoculated with the industrial strain QA23, P301.4 was never detected. In LNC, P301.4 after 12h accounted for 10% of the total population. This percentage increased after 48h (20%). Single-strain fermentations were also run in both conditions and the nitrogen metabolism further analyzed. Fermentation kinetics, ammonium and amino-acid consumptions and the expression of genes under nitrogen catabolite repression evidenced that vineyard yeasts, and particularly strain P304.4, had higher nitrogen assimilation rate than the commercial control. In conclusion, the high nitrogen assimilation rate seems to be an additional strategy that allowed vineyard yeasts successful competition during the growth in grape musts. Copyright © 2017 Elsevier B.V. All rights reserved.

Modelling nitrogen transformation and removal in mara river basin wetlands upstream of lake Victoria

Science.gov (United States)

Mayo, Aloyce W.; Muraza, Marwa; Norbert, Joel

2018-06-01

Lake Victoria, the largest lake in Africa, is a resource of social-economic potential in East Africa. This lake receives water from numerous tributaries including Mara River, which contributes about 4.8% of the total Lake water inflow. Unfortunately, Mara River basin faces environmental problems because of intensive settlement, agriculture, overgrazing in the basin and mining activities, which has lead to water pollution in the river, soil erosion and degradation, decreased soil fertility, loss of vegetation cover, decreased water infiltration capacity and increased sedimentation. One of the pollutants carried by the river includes nitrogen, which has contributed to ecological degradation of the Lake Victoria. Therefore this research work was intended to determine the effectiveness of Mara River wetland for removal of nitrogen and to establish nitrogen removal mechanisms in the wetland. To predict nitrogen removal in the wetland, the dynamics of nitrogen transformation was studied using a conceptual numerical model that takes into account of various processes in the system using STELLA II version 9.0®2006 software. Samples of model input from water, plants and sediments were taken for 45 days and were analyzed for pH, temperature, and DO in situ and chemical parameters such as NH3-N, Org-N, NO2-N, and NO3-N were analyzed in the laboratory in accordance with Standard methods. For plants, the density, dominance, biomass productivity and TN were determined and for sediments TN was analyzed. Inflow into the wetland was determined using stage-discharge relationship and was found to be 734,400 m3/day and the average wetland volume was 1,113,500 m3. Data collected by this study were used for model calibration of nitrogen transformation in this wetland while data from another wetland were used for model validation. It was found that about 37.8% of total nitrogen was removed by the wetland system largely through sedimentation (26.6%), plant uptake (6.6%) and

Nitrogen use efficiency evaluation of aerobic rice under field capacity water potential using {sup 15}N isotopic tracer technique

Energy Technology Data Exchange (ETDEWEB)

Wahid, Ahmad Nazrul Abd, E-mail: a-nazrul@nuclearmalaysia.gov.my [Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, 43600, Selangor (Malaysia); Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia); Rahim, Sahibin Abd, E-mail: haiyan@ukm.edu.my [Faculty of Science and Technology, Universiti Kebangsaan Malaysia, Bangi, 43600, Selangor (Malaysia); Rahim, Khairuddin Abdul; Harun, Abdul Rahim [Malaysian Nuclear Agency, Bangi, 43000 Kajang, Selangor (Malaysia)

2015-09-25

This study was carried out to evaluate the efficiency use of the nitrogen fertilizer on aerobic rice varieties MR219-4 and MR219-9 which were grown aerobically under field capacity water potential at the controlled environment area or shield house. Direct {sup 15}N isotope tracer method was used in this study, whereby the {sup 15}N isotope was utilized as a tracer for nitrogen nutrient uptake. {sup 15}N isotope presence in the samples is determined by using emission spectrometer analysis and percentage of total nitrogen is determined by using Kjeldahl method. {sup 15}N atom access value contained in the sample will be used in determining the effectiveness of the use of nitrogen in fertilizers through the specific calculation formulas. In this work, the data several data of nitrogen derived from fertilizer (Ndff), total nitrogen, nitrogen uptake and nitrogen use efficiency was obtained.

Nitrogen fixation in Red Sea seagrass meadows

KAUST Repository

Abdallah, Malak

2017-05-01

Seagrasses are key coastal ecosystems, providing many ecosystem services. Seagrasses increase biodiversity as they provide habitat for a large set of organisms. In addition, their structure provides hiding places to avoid predation. Seagrasses can grow in shallow marine coastal areas, but several factors regulate their growth and distribution. Seagrasses can uptake different kinds of organic and inorganic nutrients through their leaves and roots. Nitrogen and phosphorous are the most important nutrients for seagrass growth. Biological nitrogen fixation is the conversion of atmospheric nitrogen into ammonia by diazotrophic bacteria. This process provides a significant source of nitrogen for seagrass growth. The nitrogen fixation is controlled by the nif genes which are found in diazotrophs. The main goal of the project is to measure nitrogen fixation rates on seagrass sediments, in order to compare among various seagrass species from the Red Sea. Moreover, we will compare the fixing rates of the Vegetated areas with the bare sediments. This project will help to ascertain the role of nitrogen fixing bacteria in the development of seagrass meadows.

Flexible nanohybrid microelectrode based on carbon fiber wrapped by gold nanoparticles decorated nitrogen doped carbon nanotube arrays: In situ electrochemical detection in live cancer cells.

Science.gov (United States)

Zhang, Yan; Xiao, Jian; Sun, Yimin; Wang, Lu; Dong, Xulin; Ren, Jinghua; He, Wenshan; Xiao, Fei

2018-02-15

The rapidly growing demand for in situ real-time monitoring of chemical information in vitro and in vivo has attracted tremendous research efforts into the design and construction of high-performance biosensor devices. Herein, we develop a new type of flexible nanohybrid microelectrode based on carbon fiber wrapped by gold nanoparticles decorated nitrogen-doped carbon nanotube arrays, and explore its practical application in in situ electrochemical detection of cancer biomarker H 2 O 2 secreted from live cancer cells. Our results demonstrate that carbon fiber material with microscale size and fascinating mechanical properties can be used as a robust and flexible microelectrode substrate in the electrochemical biosensor system. And the highly ordered nitrogen-doped carbon nanotube arrays that grown on carbon fiber possess high surface area-to-volume ratio and abundant active sites, which facilitate the loading of high-density and uniformly dispersed gold nanoparticles on it. Benefited from the unique microstructure and excellent electrocatalytic properties of different components in the nanohybrid fiber microelectrode, an effective electrochemical sensing platform based on it has been built up for the sensitive and selective detection of H 2 O 2 , the detection limit is calculated to be 50nM when the signal-to-noise ratio is 3:1, and the linear dynamic range is up to 4.3mM, with a high sensitivity of 142µAcm -2 mM -1 . These good sensing performances, coupled with its intrinsic mechanical flexibility and biocompatibility, allow for its use in in situ real-time tracking H 2 O 2 secreted from breast cancer cell lines MCF-7 and MBA-MD-231, and evaluating the sensitivity of different cancer cells to chemotherapy or radiotherapy treatments, which hold great promise for clinic application in cancer diagnose and management. Copyright © 2017 Elsevier B.V. All rights reserved.

Redistribution of metabolic fluxes in Chlorella protothecoides by variation of media nitrogen concentration

Directory of Open Access Journals (Sweden)

Saratram Gopalakrishnan

2015-12-01

Full Text Available In this study, the Elementary Metabolite Unit (EMU algorithm was employed to calculate intracellular fluxes for Chlorella protothecoides using previously generated growth and mass spec data. While the flux through glycolysis remained relatively constant, the pentose phosphate pathway (PPP flux increased from 3% to 20% of the glucose uptake during nitrogen-limited growth. The TCA cycle flux decreased from 94% to 38% during nitrogen-limited growth while the flux of acetyl-CoA into lipids increased from 58% to 109% of the glucose uptake, increasing total lipid accumulation. Phosphoenolpyruvate carboxylase (PEPCase activity was higher during nitrogen-sufficient growth. The glyoxylate shunt was found to be partially active in both cases, indicating the nutrient nature has an impact on flux distribution. It was found that the total NADPH supply within the cell remained almost constant under both conditions. In summary, algal cells substantially reorganize their metabolism during the switch from carbon-limited (nitrogen-sufficient to nitrogen-limited (carbon-sufficient growth. Keywords: Microalgae, Biofuels, Chlorella, MFA, EMU algorithm

Evaluation of Vermicompost and Nitrogen Biofertilizer Effects on Flowering Shoot Yield, Essential Oil and Mineral Uptake (N, P and K in Summer Savory (Satureja hortensis L.

Directory of Open Access Journals (Sweden)

Mohammad Reza Haj Seyed Hadi

2018-02-01

(2.01% were obtained by using 10 ton per hectare of vermicompost. Applying 15 ton per hectare of vermicompost caused maximum flowering shoot yield (2237.82kg/ha, nitrogen (2.21% and phosphorus (0.52% content in the aboveground shoot. Mean comparison indicated that seed inoculation with Supernitroplus had significant effects on all measured traits except for nitrogen content in aboveground shoot. The maximum fresh and dry plant weight (40.21 and 14.42g/plant, flowering shoot yield (2406.21kg/ha, essential oil (2.05%, phosphorus (0.49% and potassium (1.34% were obtained by applying Supernitroplus. The maximum nitrogen content (2.23% was obtained by using Nitroxine. Results of interaction effects showed that using supernitroplus and 15 ton per hectare of vermicompost caused maximum potassium content (1.50% in Savory shoots. Several types of studies have shown a beneficial effect on crop plants by inoculation of seeds with Azospirillum and Azotobacter strains. Inoculation of plants with Azospirillum and Azotobacter can results in significant changes in various plant growth parameters. Positive effects of inoculation have been demonstrated on including increase in root length and nutrition (NO3- , NH4+, P042- , K +, Rb+ and Fe++ uptake. Nitrogen and phosphorus are the two major plant nutrients and combined inoculation of nitrogen fixers and PSM may benefit the plants better than either group of organisms alone. Interaction studies have been done both in vitro and in vivo. Nitrogen fixers and PSM when inoculated together colonized the rhizosphere and enhanced the growth of crops by providing it with nitrogen and phosphate, respectively. Vermicompost contains most of the plant nutrients such as nitrate, phosphates, exchangeable calcium and soluble potassium, and microelements which result in improved plant growth and development and is responsible for increased qualitative and quantitative yield of many crops. Conclusion The results of current experiment showed that

Global scale analysis and evaluation of an improved mechanistic representation of plant nitrogen and carbon dynamics in the Community Land Model (CLM)

Science.gov (United States)

Ghimire, B.; Riley, W. J.; Koven, C. D.; Randerson, J. T.; Mu, M.; Kattge, J.; Rogers, A.; Reich, P. B.

2014-12-01

In many ecosystems, nitrogen is the most limiting nutrient for plant growth and productivity. However mechanistic representation of nitrogen uptake linked to root traits, and functional nitrogen allocation among different leaf enzymes involved in respiration and photosynthesis is currently lacking in Earth System models. The linkage between nitrogen availability and plant productivity is simplistically represented by potential photosynthesis rates, and is subsequently downregulated depending on nitrogen supply and other nitrogen consumers in the model (e.g., nitrification). This type of potential photosynthesis rate calculation is problematic for several reasons. Firstly, plants do not photosynthesize at potential rates and then downregulate. Secondly, there is considerable subjectivity on the meaning of potential photosynthesis rates. Thirdly, there exists lack of understanding on modeling these potential photosynthesis rates in a changing climate. In addition to model structural issues in representing photosynthesis rates, the role of plant roots in nutrient acquisition have been largely ignored in Earth System models. For example, in CLM4.5, nitrogen uptake is linked to leaf level processes (e.g., primarily productivity) rather than root scale process involved in nitrogen uptake. We present a new plant model for CLM with an improved mechanistic presentation of plant nitrogen uptake based on root scale Michaelis Menten kinetics, and stronger linkages between leaf nitrogen and plant productivity by inferring relationships observed in global databases of plant traits (including the TRY database and several individual studies). We also incorporate improved representation of plant nitrogen leaf allocation, especially in tropical regions where significant over-prediction of plant growth and productivity in CLM4.5 simulations exist. We evaluate our improved global model simulations using the International Land Model Benchmarking (ILAMB) framework. We conclude that

Localization of 15N uptake in a Tibetan alpine Kobresia pasture

Science.gov (United States)

Schleuß, Per-Marten; Kuzyakov, Yakov

2014-05-01

The Kobresia Pygmea ecotone covers approximately 450.000 km2 and is of large global and regional importance due several socio-ecological aspects. For instance Kobresia pastures store high amounts of carbon, nitrogen and other nutrients, represent large grazing areas for herbivores, provide a fast regrowth after grazing events and protect against mechanical degradation and soil erosion. However, Kobresia pastures are assumed to be a grazing induced and are accompanied with distinct root mats varying in thickness between 5-30 cm. Yet, less is known about the morphology and the functions of this root mats, especially in the background of a progressing degradation due to changes of climate and management. Thus we aimed to identify the importance of single soil layers for plant nutrition. Accordingly, nitrogen uptake from different soil depths and its remain in above-ground biomass (AGB), belowground biomass (BGB) and soil were determined by using a 15N pulse labeling approach during the vegetation period in summer 2012. 15N urea was injected into six different soil depths (0.5 cm, 2.5 cm, 7.5 cm, 12.5 cm, 17.5 cm, 22.5 cm / for each 4 replicates) and plots were sampled 45 days after the labeling. For soil and BGB samples were taken in strict sample intervals of 0-1 cm, 1-5 cm, 5-10 cm, 10-15 cm, 15-20 cm, 20-25 cm. Results indicate that total recovery (including AGB, BGB and soil) was highest, if tracer was injected into the top 5 cm and subsequently decreased with decreasing injection depth. This is especially the case for the 15N recovery of BGB, which is clearly attributed to the root density and strongly decreased with soil depth. In contrast, the root activity derived from the 15N content of roots increased with soil depth, which is primary associated to a proportionate increase of living roots related to dead roots. However, most 15N was captured in plant biomass (67.5-85.3 % of total recovery), indicating high 15N uptake efficiency possibly due to N limitation

Sphagnum mosses : Masters of efficient N-uptake while avoiding intoxication

NARCIS (Netherlands)

Fritz, Christian; Lamers, Leon P.M.; Riaz, Muhammed; van den Berg, Leon J.L.; Elzenga, Theo J.T.M.

2014-01-01

Peat forming Sphagnum mosses are able to prevent the dominance of vascular plants under ombrotrophic conditions by efficiently scavenging atmospherically deposited nitrogen (N). N-uptake kinetics of these mosses are therefore expected to play a key role in differential N availability, plant

Cyclic variations in nitrogen uptake rate of soybean plants: effects of external nitrate concentration

Science.gov (United States)

Tolley-Henry, L.; Raper, C. D. Jr; Granato, T. C.; Raper CD, J. r. (Principal Investigator)

1988-01-01

Net uptake of NO3- by non-nodulated soybean plants [Glycine max (L.) Merr. cv. Ransom] growing in flowing hydroponic cultures containing 0.5, 1.0 and 10.0 mol m-3 NO3- was measured daily during a 24-d period of vegetative development to determine if amplitude of maximum and minimum rates of net NO3- uptake are responsive to external concentrations of NO3-. Removal of NO3- from the replenished solutions during each 24-h period was determined by ion chromatography. Neither dry matter accumulation nor the periodicity of oscillations in net uptake rate was altered by the external NO3- concentrations. The maxima of the oscillations in net uptake rate, however, increased nearly 3-fold in response to external NO3- concentrations. The maxima and minima, respectively, changed from 4.0 and 0.6 mmol NO3- per gram root dry weight per day at an external solution level of 0.5 mol m-3 NO3- to 15.2 and -2.7 mmol NO3- per gram root dry weight per day at an external solution level of 10.0 mol m-3 NO3-. The negative values for minimum net uptake rate from 10.0 mol m-3 NO3- solutions show that net efflux was occurring and indicate that the magnitude of the efflux component of net uptake was responsive to external concentration of NO3-.

Nitrate removal in stream ecosystems measured by 15N addition experiments: Total uptake

Science.gov (United States)

Hall, R.O.; Tank, J.L.; Sobota, D.J.; Mulholland, P.J.; O'Brien, J. M.; Dodds, W.K.; Webster, J.R.; Valett, H.M.; Poole, G.C.; Peterson, B.J.; Meyer, J.L.; McDowell, W.H.; Johnson, S.L.; Hamilton, S.K.; Grimm, N. B.; Gregory, S.V.; Dahm, Clifford N.; Cooper, L.W.; Ashkenas, L.R.; Thomas, S.M.; Sheibley, R.W.; Potter, J.D.; Niederlehner, B.R.; Johnson, L.T.; Helton, A.M.; Crenshaw, C.M.; Burgin, A.J.; Bernot, M.J.; Beaulieu, J.J.; Arangob, C.P.

2009-01-01

We measured uptake length of 15NO-3 in 72 streams in eight regions across the United States and Puerto Rico to develop quantitative predictive models on controls of NO-3 uptake length. As part of the Lotic Intersite Nitrogen eXperiment II project, we chose nine streams in each region corresponding to natural (reference), suburban-urban, and agricultural land uses. Study streams spanned a range of human land use to maximize variation in NO-3 concentration, geomorphology, and metabolism. We tested a causal model predicting controls on NO-3 uptake length using structural equation modeling. The model included concomitant measurements of ecosystem metabolism, hydraulic parameters, and nitrogen concentration. We compared this structural equation model to multiple regression models which included additional biotic, catchment, and riparian variables. The structural equation model explained 79% of the variation in log uptake length (S Wtot). Uptake length increased with specific discharge (Q/w) and increasing NO-3 concentrations, showing a loss in removal efficiency in streams with high NO-3 concentration. Uptake lengths shortened with increasing gross primary production, suggesting autotrophic assimilation dominated NO-3 removal. The fraction of catchment area as agriculture and suburban-urban land use weakly predicted NO-3 uptake in bivariate regression, and did improve prediction in a set of multiple regression models. Adding land use to the structural equation model showed that land use indirectly affected NO-3 uptake lengths via directly increasing both gross primary production and NO-3 concentration. Gross primary production shortened SWtot, while increasing NO-3 lengthened SWtot resulting in no net effect of land use on NO- 3 removal. ?? 2009.

Further contributions to the understanding of nitrogen removal in waste stabilization ponds.

Science.gov (United States)

Bastos, R K X; Rios, E N; Sánchez, I A

2018-06-01

A set of experiments were conducted in Brazil in a pilot-scale waste stabilization pond (WSP) system (a four-maturation-pond series) treating an upflow anaerobic sludge blanket (UASB) reactor effluent. Over a year and a half the pond series was monitored under two flow rate conditions, hence also different hydraulic retention times and surface loading rates. On-site and laboratory trials were carried out to assess: (i) ammonia losses by volatilization using acrylic capture chambers placed at the surface of the ponds; (ii) organic nitrogen sedimentation rates using metal buckets placed at the bottom of the ponds for collecting settled particulate matter; (iii) nitrogen removal by algal uptake based on the nitrogen content of the suspended particulate matter in samples from the ponds' water column. In addition, nitrification and denitrification rates were measured in laboratory-based experiments using pond water and sediment samples. The pond system achieved high nitrogen removal (69% total nitrogen and 92% ammonia removal). The average total nitrogen removal rates varied from 10,098 to 3,849 g N/ha·d in the first and the last ponds, respectively, with the following fractions associated with the various removal pathways: (i) 23.5-45.6% sedimentation of organic nitrogen; (ii) 13.1-27.8% algal uptake; (iii) 1.2-3.1% ammonia volatilization; and (iv) 0.15-0.34% nitrification-denitrification.

Microbial Biofertilizer Decreases Nicotine Content by Improving Soil Nitrogen Supply.

Science.gov (United States)

Shang, Cui; Chen, Anwei; Chen, Guiqiu; Li, Huanke; Guan, Song; He, Jianmin

2017-01-01

Biofertilizers have been widely used in many countries for their benefit to soil biological and physicochemical properties. A new microbial biofertilizer containing Phanerochaete chrysosporium and Bacillus thuringiensis was prepared to decrease nicotine content in tobacco leaves by regulating soil nitrogen supply. Soil NO 3 - -N, NH 4 + -N, nitrogen supply-related enzyme activities, and nitrogen accumulation in plant leaves throughout the growing period were investigated to explore the mechanism of nicotine reduction. The experimental results indicated that biofertilizer can reduce the nicotine content in tobacco leaves, with a maximum decrement of 16-18 % in mature upper leaves. In the meantime, the total nitrogen in mature lower and middle leaves increased with the application of biofertilizer, while an opposite result was observed in upper leaves. Protein concentration in leaves had similar fluctuation to that of total nitrogen in response to biofertilizer. NO 3 - -N content and nitrate reductase activity in biofertilizer-amended soil increased by 92.3 and 42.2 %, respectively, compared to those in the control, whereas the NH 4 + -N and urease activity decreased by 37.8 and 29.3 %, respectively. Nitrogen uptake was improved in the early growing stage, but this phenomenon was not observed during the late growth period. Nicotine decrease is attributing to the adjustment of biofertilizer in soil nitrogen supply and its uptake in tobacco, which result in changes of nitrogen content as well as its distribution in tobacco leaves. The application of biofertilizer containing P. chrysosporium and B. thuringiensis can reduce the nicotine content and improve tobacco quality, which may provide some useful information for tobacco cultivation.

Nitrogen and phosphorous limitation reduces the effects of land use change on land carbon uptake or emission

International Nuclear Information System (INIS)

Wang, Ying-Ping; Zhang, Qian; Dai, Yongjiu; Pitman, Andrew J

2015-01-01

We used an Earth System Model that includes both nitrogen (N) and phosphorus (P) cycling to simulate the impacts of land-use and land-cover change (LULCC) for two representative concentration pathways (RCPs): a reforestation scenario (RCP4.5) and a deforestation scenario (RCP8.5). For each RCP, we performed simulations with and without LULCC using the carbon (C only) mode or including the full C, N and P cycles (CNP). We show, for the first time, that inclusion of N and P cycling reduces both the carbon uptake from reforestation in RCP4.5 and the carbon emission from deforestation in RCP8.5. Specifically, carbon-nutrient interaction reduces carbon uptake in RCP4.5 from 55 Pg C (C only) to 21 Pg C (CNP), or the emissions in RCP8.5 from 72 Pg C (C only) to 56 Pg C (CNP). Most of those reductions result from much weaker responses of net primary production to CO 2 fertilization and climate change when carbon-nutrient interaction is taken into account, as compared to C only simulations. Our results highlight the importance of including nutrient-carbon interaction in estimating the carbon benefit from reforestation and carbon loss from deforestation in a future world with higher CO 2 and a warmer climate. Because of the stronger nutrient limitation, carbon gain from reforestation in the temperate and boreal regions is much less than the carbon loss from deforestation in the subtropical and tropical regions from 2006 to 2100 for the two RCPs. Therefore protecting the existing subtropical and tropical forests is about twice as effective as planting new forests in the temperate and boreal regions for climate mitigation. (letter)

Niche differentiation in nitrogen metabolism among methanotrophs within an operational taxonomic unit.

Science.gov (United States)

Hoefman, Sven; van der Ha, David; Boon, Nico; Vandamme, Peter; De Vos, Paul; Heylen, Kim

2014-04-04

The currently accepted thesis on nitrogenous fertilizer additions on methane oxidation activity assumes niche partitioning among methanotrophic species, with activity responses to changes in nitrogen content being dependent on the in situ methanotrophic community structure Unfortunately, widely applied tools for microbial community assessment only have a limited phylogenetic resolution mostly restricted to genus level diversity, and not to species level as often mistakenly assumed. As a consequence, intragenus or intraspecies metabolic versatility in nitrogen metabolism was never evaluated nor considered among methanotrophic bacteria as a source of differential responses of methane oxidation to nitrogen amendments. We demonstrated that fourteen genotypically different Methylomonas strains, thus distinct below the level at which most techniques assign operational taxonomic units (OTU), show a versatile physiology in their nitrogen metabolism. Differential responses, even among strains with identical 16S rRNA or pmoA gene sequences, were observed for production of nitrite and nitrous oxide from nitrate or ammonium, nitrogen fixation and tolerance to high levels of ammonium, nitrate, and hydroxylamine. Overall, reduction of nitrate to nitrite, nitrogen fixation, higher tolerance to ammonium than nitrate and tolerance and assimilation of nitrite were general features. Differential responses among closely related methanotrophic strains to overcome inhibition and toxicity from high nitrogen loads and assimilation of various nitrogen sources yield competitive fitness advantages to individual methane-oxidizing bacteria. Our observations proved that community structure at the deepest phylogenetic resolution potentially influences in situ functioning.

Interaction effect on nitrogen and sulfur on growth and nutrient uptake by maize

International Nuclear Information System (INIS)

Jaggi, R.C.; Aulakh, M.S.; Dev, G.

1977-01-01

A pot culture experiment was conducted in the greenhouse on an arid brown loamy sand deficient in both available N and S with maize (Ganga-5) as the test corp. Three levels of N (0, 30, 60 ppm) as NH 4 Cl in factorial combination with three levels of S (0, 10, 20 ppm) as Na 2 35 SO 4 were replicated thrice. Application of N upto 60 ppm S significantly increased dry matter yield and uptake of N and S by maize (stem + levels) and their combined application showed sinergistic effect for both yield and uptake of these nutrients. Maximum yield of dry matter and uptake of the nutrients were obtained with the application of 60 ppm N and 20 ppm S. The radioassay data corroborated the beneficial effect of N on the efficiency of applied S. (author)

Nutrient limitation reduces land carbon uptake in simulations with a model of combined carbon, nitrogen and phosphorus cycling

Directory of Open Access Journals (Sweden)

D. S. Goll

2012-09-01

Full Text Available Terrestrial carbon (C cycle models applied for climate projections simulate a strong increase in net primary productivity (NPP due to elevated atmospheric CO₂ concentration during the 21st century. These models usually neglect the limited availability of nitrogen (N and phosphorus (P, nutrients that commonly limit plant growth and soil carbon turnover. To investigate how the projected C sequestration is altered when stoichiometric constraints on C cycling are considered, we incorporated a P cycle into the land surface model JSBACH (Jena Scheme for Biosphere–Atmosphere Coupling in Hamburg, which already includes representations of coupled C and N cycles.

The model reveals a distinct geographic pattern of P and N limitation. Under the SRES (Special Report on Emissions Scenarios A1B scenario, the accumulated land C uptake between 1860 and 2100 is 13% (particularly at high latitudes and 16% (particularly at low latitudes lower in simulations with N and P cycling, respectively, than in simulations without nutrient cycles. The combined effect of both nutrients reduces land C uptake by 25% compared to simulations without N or P cycling. Nutrient limitation in general may be biased by the model simplicity, but the ranking of limitations is robust against the parameterization and the inflexibility of stoichiometry. After 2100, increased temperature and high CO₂ concentration cause a shift from N to P limitation at high latitudes, while nutrient limitation in the tropics declines. The increase in P limitation at high-latitudes is induced by a strong increase in NPP and the low P sorption capacity of soils, while a decline in tropical NPP due to high autotrophic respiration rates alleviates N and P limitations. The quantification of P limitation remains challenging. The poorly constrained processes of soil P sorption and biochemical mineralization are identified as the main uncertainties in the strength of P limitation

Nitrogen availability is a primary determinant of conifer mycorrhizas across complex environmental gradients

Science.gov (United States)

Filipa Cox; Nadia Barsoum; Erik A. Lilleskov; Martin I. Bidartondo

2010-01-01

Global environmental change has serious implications for functional biodiversity in temperate and boreal forests. Trees depend on mycorrhizal fungi for nutrient uptake, but predicted increases in nitrogen availability may alter fungal communities. To address a knowledge gap regarding the effects of nitrogen availability on mycorrhizal communities at large scales, we...

Uptake of allochthonous dissolved organic matter from soil and salmon in coastal temperate rainforest streams

Science.gov (United States)

Jason B. Fellman; Eran Hood; Richard T. Edwards; Jeremy B. Jones

2009-01-01

Dissolved organic matter (DOM) is an important component of aquatic food webs. We compare the uptake kinetics for NH4-N and different fractions of DOM during soil and salmon leachate additions by evaluating the uptake of organic forms of carbon (DOC) and nitrogen (DON), and proteinaceous DOM, as measured by parallel factor (PARAFAC) modeling of...

Depletion of carbohydrate reserves limits nitrate uptake during early regrowth in Lolium perenne L.

Czech Academy of Sciences Publication Activity Database

Guo, Q.; Turnbull, M.; Song, J.; Roche, J.; Novák, Ondřej; Späth, J.; Jameson, P. E.; Love, J.

2017-01-01

Roč. 68, č. 7 (2017), s. 1569-1583 ISSN 0022-0957 R&D Projects: GA ČR(CZ) GA17-06613S Institutional support: RVO:61389030 Keywords : Carbohydrate * Carbon * Cytokinin * Fructan * Lolium perenne * Nitrate transporter (NRT) * Nitrate uptake * Nitrogen * Nitrogen use efficiency (NUE) * Perennial ryegrass Subject RIV: EF - Botanics OBOR OECD: Plant sciences, botany Impact factor: 5.830, year: 2016

In situ one-step synthesis of hierarchical nitrogen-doped porous carbon for high-performance supercapacitors.

Science.gov (United States)

Jeon, Ju-Won; Sharma, Ronish; Meduri, Praveen; Arey, Bruce W; Schaef, Herbert T; Lutkenhaus, Jodie L; Lemmon, John P; Thallapally, Praveen K; Nandasiri, Manjula I; McGrail, Benard Peter; Nune, Satish K

2014-05-28

A hierarchically structured nitrogen-doped porous carbon is prepared from a nitrogen-containing isoreticular metal-organic framework (IRMOF-3) using a self-sacrificial templating method. IRMOF-3 itself provides the carbon and nitrogen content as well as the porous structure. For high carbonization temperatures (950 °C), the carbonized MOF required no further purification steps, thus eliminating the need for solvents or acid. Nitrogen content and surface area are easily controlled by the carbonization temperature. The nitrogen content decreases from 7 to 3.3 at % as carbonization temperature increases from 600 to 950 °C. There is a distinct trade-off between nitrogen content, porosity, and defects in the carbon structure. Carbonized IRMOFs are evaluated as supercapacitor electrodes. For a carbonization temperature of 950 °C, the nitrogen-doped porous carbon has an exceptionally high capacitance of 239 F g(-1). In comparison, an analogous nitrogen-free carbon bears a low capacitance of 24 F g(-1), demonstrating the importance of nitrogen dopants in the charge storage process. The route is scalable in that multi-gram quantities of nitrogen-doped porous carbons are easily produced.

Atmospheric nitrogen dioxide and northern plants

Energy Technology Data Exchange (ETDEWEB)

Aurela, A; Punkkinen, R

1981-01-01

Convincing quantitative data have recently been published about the uptake of atmospheric NO/sub 2/ by certain plants. Several qualitative pieces of evidence were found suggesting similar ability in northern plants. The volume fraction of NO/sub 2/ in the air, Phi, was measured at Kevo (70/sup 0/N, 27/sup 0/E). The Saltzman method was used, with a continuously recording detector, especially developed for measurements below the usual analytical limit of this method (0.005 ppm). The systematic error of Phi was estimated to be less than 50%. In general, Phi did not vary much with time. However, when the recorder of the atmospheric electric field at the adjacent Meteorological Station of Kevo once rose up to 4 times the normal value, the Phi-curve simultaneously rose momentarily. By using the measured value of anti-Phi, the annual uptake of NO/sub 2/-nitrogen by plants in the region of Kevo was estimated to be about 0.1 g(N)m/sup -2/ for a canopy of pines and lichens, and about 0.001 g(N)m/sup -2/ for plants at the tops of low mountains. In terms of dry weight of lichens, the uptake rate would be of the order of 0.1 ..mu..g(N)h/sup -1/ (g dry weight)/sup -1/, based on independent measurements. These amount are of the same order of magnitude as the yields of biological nitrogen fixation by lichens in corresponding conditions. A direct experimental study of the uptake of atmospheric NO/sub 2/ by northern plants seems very desirable and readily feasible.

Variability of insulin-stimulated myocardial glucose uptake in healthy elderly subjects

DEFF Research Database (Denmark)

Kofoed, Klaus F; Hove, Jens D; Freiberg, Jacob

2002-01-01

The aim of this study was to assess regional and global variability of insulin-stimulated myocardial glucose uptake in healthy elderly subjects and to evaluate potentially responsible factors. Twenty men with a mean age of 64 years, no history of cardiovascular disease, and normal blood pressure...... rest and hyperaemic blood flow during dipyridamole infusion were measured with nitrogen-13 ammonia and positron emission tomography in 16 left ventricular myocardial segments. Intra-individual and inter-individual variability of insulin-stimulated myocardial glucose uptake [relative dispersion...... = (standard deviation/mean)] was 13% and 29% respectively. Although inter-individual variability of glucose uptake and blood flow at rest was of the same magnitude, no correlation was found between these measures. Regional and global insulin-stimulated myocardial glucose uptake correlated linearly with whole...

Integration of nitrogen dynamics into the Noah-MP land surface model v1.1 for climate and environmental predictions

International Nuclear Information System (INIS)

Cai, X.; Zhang, X.

2016-01-01

Climate and terrestrial biosphere models consider nitrogen an important factor in limiting plant carbon uptake, while operational environmental models view nitrogen as the leading pollutant causing eutrophication in water bodies. The community Noah land surface model with multi-parameterization options (Noah-MP) is unique in that it is the next-generation land surface model for the Weather Research and Forecasting meteorological model and for the operational weather/climate models in the National Centers for Environmental Prediction. Here in this study, we add a capability to Noah-MP to simulate nitrogen dynamics by coupling the Fixation and Uptake of Nitrogen (FUN) plant model and the Soil and Water Assessment Tool (SWAT) soil nitrogen dynamics. This model development incorporates FUN's state-of-the-art concept of carbon cost theory and SWAT's strength in representing the impacts of agricultural management on the nitrogen cycle. Parameterizations for direct root and mycorrhizal-associated nitrogen uptake, leaf retranslocation, and symbiotic biological nitrogen fixation are employed from FUN, while parameterizations for nitrogen mineralization, nitrification, immobilization, volatilization, atmospheric deposition, and leaching are based on SWAT. The coupled model is then evaluated at the Kellogg Biological Station – a Long Term Ecological Research site within the US Corn Belt. Results show that the model performs well in capturing the major nitrogen state/flux variables (e.g., soil nitrate and nitrate leaching). Furthermore, the addition of nitrogen dynamics improves the modeling of net primary productivity and evapotranspiration. The model improvement is expected to advance the capability of Noah-MP to simultaneously predict weather and water quality in fully coupled Earth system models.

Imaging analysis of direct alanine uptake by rice seedlings

International Nuclear Information System (INIS)

Nihei, Naoto; Masuda, Sayaka; Rai, Hiroki; Nakanishi, Tomoko M.

2008-01-01

We presented alanine, a kind of amino acids, uptake by a rice seedling to study the basic mechanism of the organic fertilizer effectiveness in organic farming. The rice grown in the culture solution containing alanine as a nitrogen source absorbed alanine approximately two times faster than that grown with NH 4 + from analysis of 14 C-alanine images by Imaging Plate method. It was suggested that the active transport ability of the rice seeding was induced in roots by existence of alanine in the rhizosphere. The alanine uptake images of the rice roots were acquired every 5 minutes successively by the real-time autoradiography system we developed. The analysis of the successive images showed that alanine uptake was not uniform throughout the root but especially active at the root tip. (author)

Fluxes of oxidised and reduced nitrogen above a mixed coniferous forest exposed to various nitrogen emission sources

Energy Technology Data Exchange (ETDEWEB)

Neirynck, J. [Research Institute for Nature and Forest, Gaverstraat 4, B-9500 Geraardsbergen (Belgium)]. E-mail: johan.neirynck@inbo.be; Kowalski, A.S. [Departamento de Fisica Aplicida, Facultad de Ciencias, Universidad de Granada, Calle Fuentenueva, SP-18071 Granada (Spain); Carrara, A. [Fundacion CEAM, Parque Technologico, Calle Charles H. Darwin 14, SP-46980 Paterna (Valencia) (Spain); Genouw, G. [Research Institute for Nature and Forest, Gaverstraat 4, B-9500 Geraardsbergen (Belgium); Berghmans, P. [Flemish Institute for Technological Research, Boeretang 200, B-2400 Mol (Belgium); Ceulemans, R. [Department of Biology, University of Antwerp, Universiteitsplein 1, B-2610 Wilrijk (Antwerp) (Belgium)

2007-09-15

Concentrations of nitrogen gases (NH{sub 3}, NO{sub 2}, NO, HONO and HNO{sub 3}) and particles (pNH{sub 4} and pNO{sub 3}) were measured over a mixed coniferous forest impacted by high nitrogen loads. Nitrogen dioxide (NO{sub 2}) represented the main nitrogen form, followed by nitric oxide (NO) and ammonia (NH{sub 3}). A combination of gradient method (NH{sub 3} and NO {sub x} ) and resistance modelling techniques (HNO{sub 3}, HONO, pNH{sub 4} and pNO{sub 3}) was used to calculate dry deposition of nitrogen compounds. Net flux of NH{sub 3} amounted to -64 ng N m{sup -2} s{sup -1} over the measuring period. Net fluxes of NO {sub x} were upward (8.5 ng N m{sup -2} s{sup -1}) with highest emission in the morning. Fluxes of other gases or aerosols substantially contributed to dry deposition. Total nitrogen deposition was estimated at -48 kg N ha{sup -1} yr{sup -1} and consisted for almost 80% of NH {sub x} . Comparison of throughfall nitrogen with total deposition suggested substantial uptake of reduced N ({+-}15 kg N ha{sup -1} yr{sup -1}) within the canopy. - Reduced nitrogen was found to be the main contributor to total deposition which was predominantly governed by dry deposition.

Endocytosis of the major yolk proteins of the silkmoth, Hyalophora cecropia: Uptake kinetics and interactions

International Nuclear Information System (INIS)

Kulakosky, P.C.

1989-01-01

The oocytes of Lepidopteran insects take up several yolk proteins in defined proportions even though their relative availability in the hemolymph changes during the several days required to complete yolk formation in all the eggs. There are three hemolymph yolk precursors, vitellogenin, microvitellogenin and lipophorin; one precursor, paravitellogenin is produced in the ovary. The control mechanism for their proportional endocytosis is not known. In this thesis, the author describe the purification of all four proteins and the radiolabeling of the hemolymph precursors. The radiolabeled proteins were tested with an in vitro incubation system to assess the biological activity of the proteins and the reliability of the incubation methods. All of the labeled probes were transferred from the incubation medium to yolk spheres within the oocyte in a saturable, energy-dependent, and stage-specific manner. The rates of uptake were similar to the estimated rates of uptake in situ. The concentration dependence of in vitro uptake was investigated and found to be consistent with in situ concentrations and the composition of yolk in mature eggs. Two precursors, vitellogenin and lipophorin, competed for uptake indicating that they share a common binding site while the third, microvitellin, did not compete with the others. Though vitellogenin and lipophorin competed for uptake, only vitellogenin displayed the unique ability to increase the uptake rate of microvitellin and fluid in vitro

Dynamics of dissolved and extractable organic nitrogen upon soil amendment with crop residues

NARCIS (Netherlands)

Ros, G.H.; Hoffland, E.

2010-01-01

Dissolved organic nitrogen (DON) is increasingly recognized as a pivotal pool in the soil nitrogen (N) cycle. Numerous devices and sampling procedures have been used to estimate its size, varying from in situ collection of soil solution to extraction of dried soil with salt solutions. Extractable

Nitrogen uptake by size-fractionated phytoplankton in mangrove waters

Digital Repository Service at National Institute of Oceanography (India)

Dham, V.V.; Wafar, M.V.M.; Heredia, A.M.

to January — dry and cool) and pre-monsoon (February to May — dry and hot) periods. Environmental parameters, the nutrients and rates of N uptake and the remineralisation by unfractionated plankton were measured at 3 stations (Fig. 1) over a series of 16... samples with netplankton (20 to 200 µm) and nanoplankton (0.8 to 20 µm) sized particles were obtained by serial filtration through 200 and 20 µm bolting silk and 0.8 µm glass-fibre filters, and were used for measurements of chlorophyll a (chl a...

Processing watershed-derived nitrogen in a well-flushed New England estuary

Science.gov (United States)

Tobias, C.R.; Cieri, M.; Peterson, B.J.; Deegan, Linda A.; Vallino, J.; Hughes, J.

2003-01-01

Isotopically labeled nitrate (15NO3-) was added continuously to the Rowley estuary, Massachusetts, for 22 d to assess the transport, uptake, and cycling of terrestrially derived nitrogen during a period of high river discharge and low phytoplankton activity. Isotopic enrichment of the 3.5-km tidal prism (150,000 m3) was achieved for the 3 weeks and allowed us to construct a nitrogen mass balance model for the upper estuary. Mean ??15NO3- in the estuary ranged from 300??? to 600???, and approximately 75%-80% of the 15N was exported conservatively as 15NO 3- to the coastal ocean. Essentially all of the 20%-25% of the 15N processed in the estuary occurred in the benthos and was evenly split between direct denitrification and autotrophic assimilation. The lack of water-column 15N uptake was attributed to low phytoplankton stocks and short water residence times (1.2-1.4 d). Uptake of water-column NO3- by benthic autotrophs (enriched in excess of 100???) was a function of NO3- concentration and satisfied up to 15% and 25% of the total nitrogen demand for benthic microalgae and macroalgae, respectively. Approximately 10% of tracer assimilated by benthic autotrophs was mineralized and released back to the water column as 15NH4+. By the end of the study, 15N storage in sediments and marsh macrophytes accounted for 50%-70% of the 15N assimilated in the estuary. These compartments may sequester watershed-derived nitrogen in the estuary for time scales of months to years.

The effect of hydraulic lift on organic matter decomposition, soil nitrogen cycling, and nitrogen acquisition by a grass species.

Science.gov (United States)

Armas, Cristina; Kim, John H; Bleby, Timothy M; Jackson, Robert B

2012-01-01

Hydraulic lift (HL) is the passive movement of water through plant roots, driven by gradients in water potential. The greater soil-water availability resulting from HL may in principle lead to higher plant nutrient uptake, but the evidence for this hypothesis is not universally supported by current experiments. We grew a grass species common in North America in two-layer pots with three treatments: (1) the lower layer watered, the upper one unwatered (HL), (2) both layers watered (W), and (3) the lower layer watered, the upper one unwatered, but with continuous light 24 h a day to limit HL (no-HL). We inserted ingrowth cores filled with enriched-nitrogen organic matter ((15)N-OM) in the upper layer and tested whether decomposition, mineralization and uptake of (15)N were higher in plants performing HL than in plants without HL. Soils in the upper layer were significantly wetter in the HL treatment than in the no-HL treatment. Decomposition rates were similar in the W and HL treatments and lower in no-HL. On average, the concentration of NH(4)(+)-N in ingrowth cores was highest in the W treatment, and NO(3)(-)-N concentrations were highest in the no-HL treatment, with HL having intermediate values for both, suggesting differential mineralization of organic N among treatments. Aboveground biomass, leaf (15)N contents and the (15)N uptake in aboveground tissues were higher in W and HL than in no-HL, indicating higher nutrient uptake and improved N status of plants performing HL. However, there were no differences in total root nitrogen content or (15)N uptake by roots, indicating that HL affected plant allocation of acquired N to photosynthetic tissues. Our evidence for the role of HL in organic matter decomposition and nutrient cycling suggests that HL could have positive effects on plant nutrient dynamics and nutrient turnover.

Uptake of dissolved inorganic and organic nitrogen by the benthic toxic dinoflagellate Ostreopsis cf. ovata.

Science.gov (United States)

Jauzein, Cécile; Couet, Douglas; Blasco, Thierry; Lemée, Rodolphe

2017-05-01

Environmental factors that shape dynamics of benthic toxic blooms are largely unknown. In particular, for the toxic dinoflagellate Ostreopsis cf. ovata, the importance of the availability of nutrients and the contribution of the inorganic and organic pools to growth need to be quantified in marine coastal environments. The present study aimed at characterizing N-uptake of dissolved inorganic and organic sources by O. cf. ovata cells, using the 15 N-labelling technique. Experiments were conducted taking into account potential interactions between nutrient uptake systems as well as variations with the diel cycle. Uptake abilities of O. cf. ovata were parameterized for ammonium (NH 4 + ), nitrate (NO 3 - ) and N-urea, from the estimation of kinetic and inhibition parameters. In the range of 0 to 10μmolNL -1 , kinetic curves showed a clear preference pattern following the ranking NH 4 + >NO 3 - >N-urea, where the preferential uptake of NH 4 + relative to NO 3 - was accentuated by an inhibitory effect of NH 4 + concentration on NO 3 - uptake capabilities. Conversely, under high nutrient concentrations, the preference for NH 4 + relative to NO 3 - was largely reduced, probably because of the existence of a low-affinity high capacity inducible NO 3 - uptake system. Ability to take up nutrients in darkness could not be defined as a competitive advantage for O. cf. ovata. Species competitiveness can also be defined from nutrient uptake kinetic parameters. A strong affinity for NH 4 + was observed for O. cf. ovata cells that may partly explain the success of this toxic species during the summer season in the Bay of Villefranche-sur-mer (France). Copyright © 2017 Elsevier B.V. All rights reserved.

Convergent evidence for widespread rock nitrogen sources in Earth’s surface environment

Science.gov (United States)

Houlton, B. Z.; Morford, S. L.; Dahlgren, R. A.

2018-04-01

Nitrogen availability is a pivotal control on terrestrial carbon sequestration and global climate change. Historical and contemporary views assume that nitrogen enters Earth’s land-surface ecosystems from the atmosphere. Here we demonstrate that bedrock is a nitrogen source that rivals atmospheric nitrogen inputs across major sectors of the global terrestrial environment. Evidence drawn from the planet’s nitrogen balance, geochemical proxies, and our spatial weathering model reveal that ~19 to 31 teragrams of nitrogen are mobilized from near-surface rocks annually. About 11 to 18 teragrams of this nitrogen are chemically weathered in situ, thereby increasing the unmanaged (preindustrial) terrestrial nitrogen balance from 8 to 26%. These findings provide a global perspective to reconcile Earth’s nitrogen budget, with implications for nutrient-driven controls over the terrestrial carbon sink.

Nitrogen fixation and induction of pseudo-nodules in grass

International Nuclear Information System (INIS)

Rasul, G.; Hassan, U.; Mehnaz, S.; Malik, K.A.

1993-01-01

The rice grown nitrogen depleted saline sols showed higher values for in-situ ARA. Isolations of N/sub 2/ fixing bacteria were carried out on soil Azotobacter was observed in plant rhizosphere. The 2,4-D (0.5 and 1 ppm) with diazo trophic bacteria induced nodule like structure on the wheat roots. The bacteria were found in nodules in the form of micro colonies or bacterial aggregates which were responsible for nitrogen fixation providing optimum 02 concentrations was incorporations /sup 15/N dilution data indicated that 125-46.5% atmosphere N was incorporated in nitrogen pool of inoculated plants. (author)

[Effects of nitrogen and irrigation water application on yield, water and nitrogen utilization and soil nitrate nitrogen accumulation in summer cotton].

Science.gov (United States)

Si, Zhuan Yun; Gao, Yang; Shen, Xiao Jun; Liu, Hao; Gong, Xue Wen; Duan, Ai Wang

2017-12-01

NO 3 - -N accumulation layer moved downward. By comprehensively considering above-ground biomass, seed cotton yield, water and nitrogen uptake and utilization, and soil NO 3 - -N accumulation in the soil profile, the treatment N 3 I 1 could be recommended as the optimal water and nitrogen application pattern for summer cotton production in the experimental region.

The Impact of Nitrogen Limitation and Mycorrhizal Symbiosis on Aspen Tree Growth and Development

Energy Technology Data Exchange (ETDEWEB)

Tran, Bich Thi Ngoc [Univ. of Alabama, Huntsville, AL (United States)

2014-08-18

Nitrogen deficiency is the most common and widespread nutritional deficiency affecting plants worldwide. Ectromycorrhizal symbiosis involves the beneficial interaction of plants with soil fungi and plays a critical role in nutrient cycling, including the uptake of nitrogen from the environment. The main goal of this study is to understand how limiting nitrogen in the presence or absence of an ectomycorrhizal fungi, Laccaria bicolor, affects the health of aspen trees, Populus temuloides.

Carbon cost of plant nitrogen acquisition: global carbon cycle impact from an improved plant nitrogen cycle in the Community Land Model.

Science.gov (United States)

Shi, Mingjie; Fisher, Joshua B; Brzostek, Edward R; Phillips, Richard P

2016-03-01

Plants typically expend a significant portion of their available carbon (C) on nutrient acquisition - C that could otherwise support growth. However, given that most global terrestrial biosphere models (TBMs) do not include the C cost of nutrient acquisition, these models fail to represent current and future constraints to the land C sink. Here, we integrated a plant productivity-optimized nutrient acquisition model - the Fixation and Uptake of Nitrogen Model - into one of the most widely used TBMs, the Community Land Model. Global plant nitrogen (N) uptake is dynamically simulated in the coupled model based on the C costs of N acquisition from mycorrhizal roots, nonmycorrhizal roots, N-fixing microbes, and retranslocation (from senescing leaves). We find that at the global scale, plants spend 2.4 Pg C yr(-1) to acquire 1.0 Pg N yr(-1) , and that the C cost of N acquisition leads to a downregulation of global net primary production (NPP) by 13%. Mycorrhizal uptake represented the dominant pathway by which N is acquired, accounting for ~66% of the N uptake by plants. Notably, roots associating with arbuscular mycorrhizal (AM) fungi - generally considered for their role in phosphorus (P) acquisition - are estimated to be the primary source of global plant N uptake owing to the dominance of AM-associated plants in mid- and low-latitude biomes. Overall, our coupled model improves the representations of NPP downregulation globally and generates spatially explicit patterns of belowground C allocation, soil N uptake, and N retranslocation at the global scale. Such model improvements are critical for predicting how plant responses to altered N availability (owing to N deposition, rising atmospheric CO2 , and warming temperatures) may impact the land C sink. © 2015 John Wiley & Sons Ltd.

Uptake of radionuclides by vegetation at a High Arctic location

International Nuclear Information System (INIS)

Dowdall, M.; Gwynn, J.P.; Moran, C.; O'Dea, J.; Davids, C.; Lind, B.

2005-01-01

Radionuclide levels in vegetation from a High Arctic location were studied and compared to in situ soil concentrations. Levels of the anthropogenic radionuclide 137 Cs and the natural radionuclides 40 K, 238 U, 226 Ra and 232 Th are discussed and transfer factor (TF) values and aggregated transfer (Tag) values are calculated for vascular plants. Levels of 137 Cs in vegetation generally followed the order mosses > lichen > vascular plants. The uptake of 137 Cs in vascular plants showed an inverse relationship with the uptake of 40 K, with 137 Cs TF and Tag values generally higher than 40 K TF and Tag values. 40 K activity concentrations in all vegetation showed little correlation to associated soil concentrations, while the uptake of 238 U, 226 Ra and 232 Th by vascular and non-vascular plants was generally low. - Uptake of the anthropogenic radionuclide 137 Cs is highest for moss species

Fate of nitrogenous fertilizers in forest soil

International Nuclear Information System (INIS)

Pang, P.C.K.

1984-01-01

The fate of the nitrogenous fertilizers through the processes of denitrification, ammonia volatilization, immobilization and uptake by a conifer is determined, with the aid of 15 N-labelled fertizers. The foliage of Douglas-fir was able to absorb gaseous ammonia under optimal conditions. Denitrification and immobilization of fertilizer-N by forest soil were highest with forest floor samples and decreased with depth. Laboratory studies with four-year-old Douglas-fir demostrated that a higher quantity of fertilizer-N was utilized by trees when the nitrogen was supplied as NO 3 - rather than NH 4 + . (M.A.C.) [pt

Inoculation with arbuscular mycorrhizae does not improve 137Cs uptake in crops grown in the Chernobyl region.

Science.gov (United States)

Vinichuk, M; Mårtensson, A; Rosén, K

2013-12-01

Methods for cleaning up radioactive contaminated soils are urgently needed. In this study we investigated whether the use of arbuscular mycorrhizal (AM) fungi can improve (137)Cs uptake by crops. Barley, cucumber, perennial ryegrass, and sunflower were inoculated with AM fungi and grown in low-level radionuclide contaminated soils in a field experiment 70 km southwest of Chernobyl, Ukraine, during two successive years (2009-2010). Roots of barley, cucumber and sunflower plants were slightly or moderately infected with AM fungus and root infection frequency was negatively or non-correlated with (137)Cs uptake by plants. Roots of ryegrass were moderately infected with AM fungus and infection frequency was moderately correlated with (137)Cs uptake by ryegrass. The application of AM fungi to soil in situ did not enhance radionuclide plant uptake or biomass. The responsiveness of host plants and AM fungus combination to (137)Cs uptake varied depending on the soil, although mycorrhization of soil in the field was conditional and did not facilitate the uptake of radiocesium. The total amount of (137)Cs uptake by plants growing on inoculated soil was equal to amounts in plant cultivated on non-inoculated soil. Thus, the use of AM fungi in situ for bioremediation of soil contaminated with a low concentration of (137)Cs could not be recommended. Copyright © 2013 Elsevier Ltd. All rights reserved.

The effect of light supply on microalgal growth, CO2 uptake and nutrient removal from wastewater

International Nuclear Information System (INIS)

Gonçalves, A.L.; Simões, M.; Pires, J.C.M.

2014-01-01

Highlights: • Effect of irradiance and light:dark ratio on microalgal growth was analysed. • Microalgal growth, CO 2 capture, nitrogen and phosphorus uptake were evaluated. • Higher irradiances and light periods supported higher growth and CO 2 uptake rates. • All the studied microalgal strains have shown high nitrogen removal efficiencies. • The highest phosphorus removal efficiency was 67.6%. - Abstract: Microalgal based biofuels have been reported as an attractive alternative for fossil fuels, since they constitute a renewable energy source that reduces greenhouse gas emissions to the atmosphere. However, producing biofuels from microalgae is still not economically viable. Therefore, the integration of biofuel production with other microalgal applications, such as CO 2 capture and nutrient removal from wastewaters, would reduce the microalgal production costs (and the environmental impact of cultures), increasing the economic viability of the whole process. Additionally, producing biofuels from microalgae strongly depends on microalgal strain and culture conditions. This study evaluates the effect of culture conditions, namely light irradiance (36, 60, 120 and 180 μE m −2 s −1 ) and light:dark ratio (10:14, 14:10 and 24:0), on microalgal growth, atmospheric CO 2 uptake and nutrient (nitrogen and phosphorous) removal from culture medium. Four different microalgal strains, Chlorella vulgaris, Pseudokirchneriella subcapitata, Synechocystis salina and Microcystis aeruginosa, were studied to ascertain the most advantageous regarding the referred applications. This study has shown that higher light irradiance values and light periods resulted in higher specific growth rates and CO 2 uptake rates. C. vulgaris presented the highest specific growth rate and CO 2 uptake rate: 1.190 ± 0.041 d −1 and 0.471 ± 0.047 g CO2 L −1 d −1 , respectively. All the strains have shown high nitrogen removal efficiencies, reaching 100% removal percentages in

Effects of biochar addition to soil on nitrogen fluxes in a winter wheat lysimeter experiment

Science.gov (United States)

Hüppi, Roman; Leifeld, Jens; Neftel, Albrecht; Conen, Franz; Six, Johan

2014-05-01

Biochar is a carbon-rich, porous residue from pyrolysis of biomass that potentially increases crop yields by reducing losses of nitrogen from soils and/or enhancing the uptake of applied fertiliser by the crops. Previous research is scarce about biochar's ability to increase wheat yields in temperate soils or how it changes nitrogen dynamics in the field. In a lysimeter system with two different soils (sandy/silt loam) nitrogen fluxes were traced by isotopic 15N enriched fertiliser to identify changes in nitrous oxide emissions, leaching and plant uptake after biochar addition. 20t/ha woodchip-waste biochar (pH=13) was applied to these soils in four lysimeters per soil type; the same number of lysimeters served as a control. The soils were cropped with winter wheat during the season 2012/2013. 170 kg-N/ha ammonium nitrate fertiliser with 10% 15N was applied in 3 events during the growing season and 15N concentrations where measured at different points in time in plant, soil, leachate and emitted nitrous oxide. After one year the lysimeter system showed no difference between biochar and control treatment in grain- and straw yield or nitrogen uptake. However biochar did reduce nitrous oxide emissions in the silt loam and losses of nitrate leaching in sandy loam. This study indicates potential reduction of nitrogen loss from cropland soil by biochar application but could not confirm increased yields in an intensive wheat production system.

effect of irrigation with sewage wastewater on nitrogen uptake, translocation and orange fruit quality under el-gabal el-asfar condition: the use of 15N-labelled fertilizer

International Nuclear Information System (INIS)

Hussien, M.E.H.

2008-01-01

The uptake and translocation of nitrogen from sewage water and mineral fertilizer by one year old Navel orange transplants was investigated at a greenhouse pot experiment during (2005 and 2006) seasons. An isotope-aided study using 15 N-labelled ammonium sulfate was applied around the stem to assess the percentage of nitrogen in plants that is derived from fertilizer. The 15 N ammonium sulfate was applied at a rate of (6 g / pot).Treatments included irrigation with canal water or sewage water in addition to half strength Hoagland nutrient solution. Pots were irrigated to maintain the soil moisture content at field capacity. Results indicated an increase in transplants biomass using sewage water than using canal water for irrigation. A substantial increase in mineral fertilizer nitrogen uptake by roots and translocation into shoots was observed using canal water than using sewage water. Fertilizer nitrogen recovery by orange transplants under both kinds of water was low. However, fertilizer nitrogen recovery was higher under canal water than under sewage water irrigation regime although the plant biomass was higher under sewage water.The percent nitrogen derived from sewage water was higher (26.1- 49.5 %) comparing with the percent nitrogen (4.9 - 12.7 %) derived from 15 N-labelled ammonium sulfate Twenty years old Navel orange trees were selected for this study. Treatments included trees grown at field sites that have been irrigated with sewage water (S.W.) for 20, 50 and 90 years. Navel orange trees, of the same age, grown at a farm in Inshas using canal water (C.W.) from (Ismailia canal a branch of the River Nile) as a source for irrigation, was included in this study as the control. Fruits were sampled at maturity and ripening stages. Results of the physical characteristics of the fruits showed an increase in fruit weight, volume, but reduction in firmness and color development (from green to yellow color) relative to the control and as the irrigation period

The effect of elevated cadmium content in soil on the uptake of nitrogen by plants

Energy Technology Data Exchange (ETDEWEB)

Ciecko, Z.; Kalembasa, S.; Wyszkowski, M.; Rolka, E. [University of Warmia & Mazury Olsztyn, Olsztyn (Poland). Dept. of Environmental Chemistry

2004-07-01

The aim of this study was to determine the effect of cadmium (10, 20, 30 and 40 mg Cd/kg of soil) contamination in soil with the application of different substances (compost, brown coal, lime and bentonite) on the intake of nitrogen by some plants. The correlations between the nitrogen content in the plants and the cadmium concentration in the soil, as well as the plant yield and the content of micro- and macroelements in the plants were determined. Plant species and cadmium dose determined the effects of soil contamination with cadmium on the content of nitrogen. Large doses of cadmium caused an increase in nitrogen content in the Avena sativa straw and roots and in the Zea mays roots. Soil contamination with cadmium resulted in a decrease of nitrogen content in the Avena sativa grain, in above-ground parts and roots of the Lupinus luteus, in the above-ground parts of the Zea mays and in the above-ground parts and roots of Phacelia tanacaetifolia. Among the experimental different substances, the application of bentonite had the strongest and a usually negative effect on the nitrogen content in plants. The greatest effect of bentonite was on Avena sativa grain, above-ground parts Zea mays and Lupinus luteus and Phacelia tanacaetifolia. The content of nitrogen in the plants was generally positively correlated with the content of the macroelements and some of the microelements, regardless of the substances added to the soil.

Robust biological nitrogen fixation in a model grass-bacterial association.

Science.gov (United States)

Pankievicz, Vânia C S; do Amaral, Fernanda P; Santos, Karina F D N; Agtuca, Beverly; Xu, Youwen; Schueller, Michael J; Arisi, Ana Carolina M; Steffens, Maria B R; de Souza, Emanuel M; Pedrosa, Fábio O; Stacey, Gary; Ferrieri, Richard A

2015-03-01

Nitrogen-fixing rhizobacteria can promote plant growth; however, it is controversial whether biological nitrogen fixation (BNF) from associative interaction contributes to growth promotion. The roots of Setaria viridis, a model C4 grass, were effectively colonized by bacterial inoculants resulting in a significant enhancement of growth. Nitrogen-13 tracer studies provided direct evidence for tracer uptake by the host plant and incorporation into protein. Indeed, plants showed robust growth under nitrogen-limiting conditions when inoculated with an ammonium-excreting strain of Azospirillum brasilense. (11)C-labeling experiments showed that patterns in central carbon metabolism and resource allocation exhibited by nitrogen-starved plants were largely reversed by bacterial inoculation, such that they resembled plants grown under nitrogen-sufficient conditions. Adoption of S. viridis as a model should promote research into the mechanisms of associative nitrogen fixation with the ultimate goal of greater adoption of BNF for sustainable crop production. © 2015 The Authors The Plant Journal © 2015 John Wiley & Sons Ltd.

Effect of different doses of urea on the uptake of cadmium from soil ...

African Journals Online (AJOL)

Yomi

2012-01-19

Jan 19, 2012 ... uptake by canola (Brassica napus L.) applied in full and split doses. Nine different ... production of ruminants being reared on the pasture. Key words: ... combined nitrogen fertilizer used in today's agricultural practices ...

Enhancing the biological nitrogen fixation of leguminous crops ...

African Journals Online (AJOL)

Legumes have the ability to establish a symbiotic interaction with soil bacteria, collectively termed as rhizobia. These bacteria can enhance growth and development of associated crops by transferring atmospheric nitrogen into a form that is available for plant growth or by improving nutrient uptake through modulation of ...

Bandgap tailoring of in-situ nitrogen-doped TiO₂ sputtered films intended for electrophotocatalytic applications under solar light

Energy Technology Data Exchange (ETDEWEB)

Delegan, N.; El Khakani, M. A., E-mail: elkhakani@emt.inrs.ca [Institut National de la Recherche Scientifique, Centre Énergie, Matériaux et Télécommunications, 1650, Boulevard Lionel-Boulet, Varennes, Québec J3X-1S2 (Canada); Daghrir, R.; Drogui, P. [Institut National de la Recherche Scientifique, Centre Eau, Terre et Environnement, 490 Rue de la Couronne, Québec G1K-9A9 (Canada)

2014-10-21

We report on a reactive RF-sputtering process permitting the in-situ nitrogen doping of TiO₂ films in order to shift their photoactivity from UV to visible range. By carefully controlling the relative nitrogen-to-argon mass flow rate ratio (within the 0%–25% range) in the sputter deposition chamber, TiO₂:N films were grown with nitrogen contents ranging from 0 to 6.2 at. %, as determined by high-resolution X-ray spectroscopy measurements. A systematic investigation of the crystalline structure of the TiO₂:N films, as a function of their N content, revealed that low N contents (0.2–0.3 at. %) induce crystallization in the rutile phase while higher N contents (≥1.4 at. %) were accompanied with the recovery of the anatase structure with an average crystallite size of ~35 nm. By using both UV-Vis absorption and spectroscopic ellipsometry measurements, we were able to quantitatively determine the bandgap (E{sub g}) variation of the TiO₂:N films as a function of their N content. Thus, we have demonstrated that the E{sub g} of the TiO₂:N films effectively narrows from 3.2 eV down to a value as low as ~2.3 eV for the optimal N doping concentration of 3.4 at. % (higher N incorporation does not translate into further red shifting of the TiO₂:N films' E{sub g}). The photoactivity of the TiO₂:N films under visible light was confirmed through electro-photocatalytic decomposition of chlortetracycline (CTC, an emerging water pollutant) under standard 1.5AM solar radiation. Thus, CTC degradation efficiencies of up to 98% were achieved with 2 hours process cycles under simulated solar light. Moreover, the electro-photocatalytic performance of the TiO₂:N films is shown to be directly correlated to their optoelectronic properties (namely their bandgap narrowing).

The effect of concentration and exposure time on 15N uptake and incorporation from urea and ammonium nitrate by spring barley in the initial growth period

International Nuclear Information System (INIS)

Matula, J.; Knop, K.

1978-01-01

The uptake and incorporation of 15 N from urea and ammonium nitrate by spring barley were studied in aquaculture at three nitrogen concentrations in complex nutrient solutions (28, 140 and 700 mg N per 1 litre) and for three lengths of exposure to 15 N-labelled nutrient solutions. The 'Diamant' variety plants were precultivated up to the stage of the 3rd to 4th leaf in a complex nutrient solution, and five days prior to exposure to 15 N-labelled solutions the plants were cultivated in a nutrient solution without nitrogen. At a concentration of 28 mg N per litre the course of urea absorption was similar to the absorption of ammonium nitrate, but at a lower level. The results suggest that urea uptake is basically controlled by the metabolic requirement, particularly at lower concentrations. Only at the highest concentrations of nitrogen in the nutrient solutions did the 15 N of urea and ammonium nitrate penetrate into the roots, passive uptake being preferred. The uptake of urea is controlled by the metabolic requirement but its availability for barley metabolism is lower. Ammonium nitrate NO 3 - was taken up at a lower rate than NH 4 + from the same compound. Nitrate nitrogen was transported relatively more intensively to the above-ground parts of barley. The increasing concentration of nitrogen and exposure to nutrient solutions induced a rise in the proportion of ethanol-soluble forms of nitrogen, particularly in the roots. (author)

Nitrogen fixation by cyanobacteria stimulates production in Baltic food webs.

Science.gov (United States)

Karlson, Agnes M L; Duberg, Jon; Motwani, Nisha H; Hogfors, Hedvig; Klawonn, Isabell; Ploug, Helle; Barthel Svedén, Jennie; Garbaras, Andrius; Sundelin, Brita; Hajdu, Susanna; Larsson, Ulf; Elmgren, Ragnar; Gorokhova, Elena

2015-06-01

Filamentous, nitrogen-fixing cyanobacteria form extensive summer blooms in the Baltic Sea. Their ability to fix dissolved N2 allows cyanobacteria to circumvent the general summer nitrogen limitation, while also generating a supply of novel bioavailable nitrogen for the food web. However, the fate of the nitrogen fixed by cyanobacteria remains unresolved, as does its importance for secondary production in the Baltic Sea. Here, we synthesize recent experimental and field studies providing strong empirical evidence that cyanobacterial nitrogen is efficiently assimilated and transferred in Baltic food webs via two major pathways: directly by grazing on fresh or decaying cyanobacteria and indirectly through the uptake by other phytoplankton and microbes of bioavailable nitrogen exuded from cyanobacterial cells. This information is an essential step toward guiding nutrient management to minimize noxious blooms without overly reducing secondary production, and ultimately most probably fish production in the Baltic Sea.

Inoculation with arbuscular mycorrhizae does not improve 137Cs uptake in crops grown in the Chernobyl region

International Nuclear Information System (INIS)

Vinichuk, M.; Mårtensson, A.; Rosén, K.

2013-01-01

Methods for cleaning up radioactive contaminated soils are urgently needed. In this study we investigated whether the use of arbuscular mycorrhizal (AM) fungi can improve 137 Cs uptake by crops. Barley, cucumber, perennial ryegrass, and sunflower were inoculated with AM fungi and grown in low-level radionuclide contaminated soils in a field experiment 70 km southwest of Chernobyl, Ukraine, during two successive years (2009–2010). Roots of barley, cucumber and sunflower plants were slightly or moderately infected with AM fungus and root infection frequency was negatively or non-correlated with 137 Cs uptake by plants. Roots of ryegrass were moderately infected with AM fungus and infection frequency was moderately correlated with 137 Cs uptake by ryegrass. The application of AM fungi to soil in situ did not enhance radionuclide plant uptake or biomass. The responsiveness of host plants and AM fungus combination to 137 Cs uptake varied depending on the soil, although mycorrhization of soil in the field was conditional and did not facilitate the uptake of radiocesium. The total amount of 137 Cs uptake by plants growing on inoculated soil was equal to amounts in plant cultivated on non-inoculated soil. Thus, the use of AM fungi in situ for bioremediation of soil contaminated with a low concentration of 137 Cs could not be recommended. -- Highlights: • Effect of mycorrhization on 137 Cs uptake by crops was studied in a field experiment. • AM fungi did not enhance radionuclide plant uptake or biomass. • Plants growing on inoculated and non-inoculated soil accumulate 137 Cs equally

Nitrate and Nitrogen Oxides: Sources, Health Effects and Their Remediation.

Science.gov (United States)

Hakeem, Khalid Rehman; Sabir, Muhammad; Ozturk, Munir; Akhtar, Mohd Sayeed; Ibrahim, Faridah Hanum

Increased use of nitrogenous (N) fertilizers in agriculture has significantly altered the global N-cycle because they release nitrogenous gases of environmental concerns. The emission of nitrous oxide (N 2 O) contributes to the global greenhouse gas accumulation and the stratospheric ozone depletion. In addition, it causes nitrate leaching problem deteriorating ground water quality. The nitrate toxicity has been reported in a number of studies showing the health hazards like methemoglobinemia in infants and is a potent cause of cancer. Despite these evident negative environmental as well as health impacts, consumption of N fertilizer cannot be reduced in view of the food security for the teeming growing world population. Various agronomic and genetic modifications have been practiced to tackle this problem. Some agronomic techniques adopted include split application of N, use of slow-release fertilizers, nitrification inhibitors and encouraging the use of organic manure over chemical fertilizers. As a matter of fact, the use of chemical means to remediate nitrate from the environment is very difficult and costly. Particularly, removal of nitrate from water is difficult task because it is chemically non-reactive in dilute aqueous solutions. Hence, the use of biological means for nitrate remediation offers a promising strategy to minimize the ill effects of nitrates and nitrites. One of the important goals to reduce N-fertilizer application can be effectively achieved by choosing N-efficient genotypes. This will ensure the optimum uptake of applied N in a balanced manner and exploring the molecular mechanisms for their uptake as well as metabolism in assimilatory pathways. The objectives of this paper are to evaluate the interrelations which exist in the terrestrial ecosystems between the plant type and characteristics of nutrient uptake and analyze the global consumption and demand for fertilizer nitrogen in relation to cereal production, evaluate the various

Simple fabrication of solid phase microextraction fiber employing nitrogen-doped ordered mesoporous polymer by in situ polymerization.

Science.gov (United States)

Zheng, Juan; Liang, Yeru; Liu, Shuqin; Jiang, Ruifen; Zhu, Fang; Wu, Dingcai; Ouyang, Gangfeng

2016-01-04

A combination of nitrogen-doped ordered mesoporous polymer (NOMP) and stainless steel wires led to highly sensitive, selective, and stable solid phase microextraction (SPME) fibers by in situ polymerization for the first time. The ordered structure of synthesized NOMP coating was illustrated by transmission electron microscopy (TEM) and X-ray diffraction (XRD), and microscopy analysis by scanning electron microscopy (SEM) confirmed a homogenous morphology of the NOMP-coated fiber. The NOMP-coated fiber was further applied for the extraction of organochlorine pesticides (OCPs) with direct-immersion solid-phase microextraction (DI-SPME) method followed by gas chromatography-mass spectrometry (GC-MS) quantification. Under the optimized conditions, low detection limits (0.023-0.77 ng L(-1)), a wide linear range (9-1500 ng L(-1)), good repeatability (3.5-8.1%, n=6) and excellent reproducibility (1.5-8.3%, n=3) were achieved. Moreover, the practical feasibility of the proposed method was evaluated by determining OCPs in environmental water samples with satisfactory recoveries. Copyright © 2015 Elsevier B.V. All rights reserved.

Modeling Nitrogen Decrease in Water Lettuce Ponds from Waste Stabilization Ponds

Science.gov (United States)

Putri, Gitta Agnes; Sunarsih

2018-02-01

This paper presents about the dynamic modeling of the Water Lettuce ponds as a form of improvement from the Water Hyacinth ponds. The purpose of this paper is to predict nitrogen decrease and nitrogen transformation in Water Lettuce ponds integrated with Waste Stabilization Ponds. The model consists of 4 mass balances, namely Dissolved Organic Nitrogen (DON), Particulate Organic Nitrogen (PON), ammonium (NH4+), Nitrate and Nitrite (NOx). The process of nitrogen transformation which considered in a Water Lettuce ponds, namely hydrolysis, mineralization, nitrification, denitrification, plant and bacterial uptake processes. Numerical simulations are performed by giving the values of parameters and the initial values of nitrogen compounds based on a review of previous studies. Numerical results show that the rate of change in the concentration of nitrogen compounds in the integration ponds of waste stabilization and water lettuce decreases and reaches stable at different times.

Effects of sulfur and nitrogen on nutrients uptake of corn using ...

African Journals Online (AJOL)

Jane

2011-08-08

Aug 8, 2011 ... Sulfur uptake efficiency increases, and the deficiency symptom disappears, upon application of N fertilizer in the form of urea in S deficient soil (Murphy, 1999). Sulfur is considered one of the major essential plant nutrients and an amendment used for reclaiming alkaline and calcareous soils (Marschner ...

Interactive Influence of N and P on their uptake by four different ...

African Journals Online (AJOL)

STORAGESEVER

2008-10-06

Oct 6, 2008 ... refreshment, the plants were left for 3 days in hydroponic culture without nitrogen ... The pH of the uptake solution was adjusted to 5.6 using 0.1 mmol/l HCl. ..... ascorbate specific peroxidase in spinach chloroplasts. Plant Cell.

Uptake and distribution of combined nitrogen and its incorporation into seeds of nodulated soybean plants as revealed by 15N studies

International Nuclear Information System (INIS)

Rabie, R.K.; Arima, Yasuhiro; Kumazawa, Kikuo

1980-01-01

Pot experiments were carried out with soybean plants grown with N-free solution, then supplied with NO 3 - or NH 4 + before 15 N administration, in order to study the uptake, distribution and redistribution of absorbed nitrogen. To determine the utilization and incorporation of combined nitrogen to the yield of seeds, as influenced by the form of N and application time, another series of experiments was carried out, in which the plants were grown with N-free solution, then 15 N was fed as 15 NO 3 - or 15 NH 4 + at pod setting stage (PS) or initial pod filling stage (IPF). By comparing the nitrate-treated plants (Nt plants) with the ammonia-treated ones (Am plants), and the treatment at PS with that at IPF, the following results were obtained. Nt plants accumulated larger amount of dry matters in respective plant parts than Am plants, particularly in the pods, and it was proved that the pods were the active sinks for newly metabolized nitrate. Both 15 N abundance and 15 N incorporation in the whole plants were much higher in Nt plants, and those in respective plant parts except nodules were also higher in Nt plants. Large part of the 15 N in roots was redistributed to the top parts in Nt plants, while large part of the absorbed N was distributed to the nodules in Am plants. Some more results are reported. (Kako, I.)

Intercropping effect on root growth and nitrogen uptake at different nitrogen levels

DEFF Research Database (Denmark)

Ramirez-Garcia, Javier; Martens, Helle Juel; Quemada, Miguel

2015-01-01

of root growth and N foraging for barley (Hordeum vulgare L.) and vetch (Vicia sativa L.), frequently grown in mixtures as cover crops. N was added at 0 (N0), 50 (N1) and 150 (N2) kg N ha−1. The roots discrimination relying on the anatomical and morphological differences observed between dicots......Aims Intercropping legumes and non-legumes may affect the root growth of both components in the mixture, and the non-legume is known to be strongly favored by increasing nitrogen (N) supply. The knowledge of how root systems affect the growth of the individual species is useful for understanding...... the interactions in intercrops as well as for planning cover cropping strategies. The aim of this work was (i) to determine if different levels of N in the topsoil influence root depth (RD) and intensity of barley and vetch as sole crops or as an intercropped mixture and (ii) to test if the choice of a mixture...

Coupling nutrient uptake and energy flow in headwater streams

Energy Technology Data Exchange (ETDEWEB)

Mulholland, Patrick J [ORNL; Fellows, Christine [Griffith University, Nathan, Queensland, Australia; Valett, H. Maurice [Virginia Polytechnic Institute and State University (Virginia Tech); Dahm, Cliff [University of New Mexico, Albuquerque; Thomas, Steve [University of Nebraska

2006-08-01

Nutrient cycling and energy flow in ecosystems are tightly linked through the metabolic processes of organisms. Greater uptake of inorganic nutrients is expected to be associated with higher rates of metabolism [gross primary production (GPP) and respiration (R)], due to assimilatory demand of both autotrophs and heterotrophs. However, relationships between uptake and metabolism should vary with the relative contribution of autochthonous and allochthonous sources of organic matter. To investigate the relationship between metabolism and nutrient uptake, we used whole-stream and benthic chamber methods to measure rates of nitrate-nitrogen (NO{sub 3}-N) uptake and metabolism in four headwater streams chosen to span a range of light availability and therefore differing rates of GPP and contributions of autochthonous carbon. We coupled whole-stream metabolism with measures of NO{sub 3}-N uptake conducted repeatedly over the same stream reach during both day and night, as well as incubating benthic sediments under both light and dark conditions. NO{sub 3}-N uptake was generally greater in daylight compared to dark conditions, and although day-night differences in whole-stream uptake were not significant, light-dark differences in benthic chambers were significant at three of the four sites. Estimates of N demand indicated that assimilation by photoautotrophs could account for the majority of NO{sub 3}-N uptake at the two sites with relatively open canopies. Contrary to expectations, photoautotrophs contributed substantially to NO{sub 3}-N uptake even at the two closed-canopy sites, which had low values of GPP/R and relied heavily on allochthonous carbon to fuel R.

Effectiveness of liquid organic-nitrogen fertilizer in enhancing ...

African Journals Online (AJOL)

The ever increasing price of nitrogenous (N) fertilizers coupled with the deleterious effects of imbalanced N fertilizers on the environment necessitates the enhancement of N use efficiency of plants. The objectives of this study were to: (1) Evaluate the uptake of selected nutrients due to application of liquid organic-N ...

Effects of sulfur and nitrogen on nutrients uptake of corn using ...

African Journals Online (AJOL)

N) fertilizer using acidified water (pH 6.5) to determine nutrients uptake and growth of maize plants grown in calcareous sandy soil. Four levels of elemental sulfur (0, 1, 5 and 10 t ha-1), two levels of N (0 and 0.34 t N ha-1) were tested at Al ...

Convergent evidence for widespread rock nitrogen sources in Earth's surface environment.

Science.gov (United States)

Houlton, B Z; Morford, S L; Dahlgren, R A

2018-04-06

Nitrogen availability is a pivotal control on terrestrial carbon sequestration and global climate change. Historical and contemporary views assume that nitrogen enters Earth's land-surface ecosystems from the atmosphere. Here we demonstrate that bedrock is a nitrogen source that rivals atmospheric nitrogen inputs across major sectors of the global terrestrial environment. Evidence drawn from the planet's nitrogen balance, geochemical proxies, and our spatial weathering model reveal that ~19 to 31 teragrams of nitrogen are mobilized from near-surface rocks annually. About 11 to 18 teragrams of this nitrogen are chemically weathered in situ, thereby increasing the unmanaged (preindustrial) terrestrial nitrogen balance from 8 to 26%. These findings provide a global perspective to reconcile Earth's nitrogen budget, with implications for nutrient-driven controls over the terrestrial carbon sink. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Synthesis of nitrogen-doped graphene via solid microwave method

Energy Technology Data Exchange (ETDEWEB)

Zhang, Li, E-mail: zhangli379@sohu.com [School of Electrical Engineering, Dalian University of Technology, Dalian, Liaoning 116024 (China); Ji, Bingcheng, E-mail: debbo.jee@outlook.com [School of Electrical Engineering, Dalian University of Technology, Dalian, Liaoning 116024 (China); Wang, Kai [School of Electrical Engineering, Dalian University of Technology, Dalian, Liaoning 116024 (China); Song, Jinyan [School of Information Engineering, Dalian Ocean University, Dalian, Liaoning 116024 (China)

2014-07-01

Graphical abstract: - Highlights: • A direct solid microwave method is developed to prepare nitrogen-doped graphene. • The method consists of two steps, namely the functionalization and microwave irradiation. • Melamine can serve as not only functionalizing agent but also nitrogen source. - Abstract: In this paper, we propose a solid microwave-mediated method for scalable production of nitrogen-doped graphene sheets (NGS) using low-cost industrial material melamine as functionalizing agent and nitrogen source. The strong interaction of microwaves with graphene oxide has been fully utilized to generate in situ heating that induces the decompose melamine and nitrogen doping of graphene. The morphology, structure, and components of the as-produced nitrogen-doped graphene are characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Brunauer–Emmett–Teller (BET), pore-size distribution (PSD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectra (XPS), X-ray diffraction (XRD), and Raman spectroscopy. The results show NGS can be successfully synthesized via this strategy.

Synthesis of nitrogen-doped graphene via solid microwave method

International Nuclear Information System (INIS)

Zhang, Li; Ji, Bingcheng; Wang, Kai; Song, Jinyan

2014-01-01

Graphical abstract: - Highlights: • A direct solid microwave method is developed to prepare nitrogen-doped graphene. • The method consists of two steps, namely the functionalization and microwave irradiation. • Melamine can serve as not only functionalizing agent but also nitrogen source. - Abstract: In this paper, we propose a solid microwave-mediated method for scalable production of nitrogen-doped graphene sheets (NGS) using low-cost industrial material melamine as functionalizing agent and nitrogen source. The strong interaction of microwaves with graphene oxide has been fully utilized to generate in situ heating that induces the decompose melamine and nitrogen doping of graphene. The morphology, structure, and components of the as-produced nitrogen-doped graphene are characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Brunauer–Emmett–Teller (BET), pore-size distribution (PSD), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectra (XPS), X-ray diffraction (XRD), and Raman spectroscopy. The results show NGS can be successfully synthesized via this strategy

Carbon-nitrogen interactions and biomass partitioning of Carex rostrata grown at three levels of nitrogen supply

Energy Technology Data Exchange (ETDEWEB)

Saarinen, T [Helsinki Univ. (Finland). Dept. of Ecology and Systematics

1997-12-31

Biomass and production of vascular plants constitutes a major source of carbon input in peatlands. As rates of decomposition vary considerably with depth, the vertical distribution of biomass may substantially affect accumulation of carbon in peatlands. Therefore, allocation patterns between shoot and roots are particularly important when considering carbon balance of peatland ecosystems. The stimulatory effect of increasing atmospheric concentration of CO{sub 2} or photosynthesis may increase availability of carbon to most C3 plants. Availability of nitrogen may also alter both due to increased atmospheric deposition and changer in mineralisation rates associated with climate change. Most root-shoot partitioning models predict that allocation of biomass is dependent of the availability and uptake of carbon and nitrogen. A decrease in supply of carbon would favour allocation to shoots and a decrease in supply of nitrogen would increase allocation to roots. At a cellular level, non structural carbohydrates and free amino acids are thought to represent the biochemically available fraction of carbon and nitrogen, respectively. The aim of this work is study the long-term growth responses of Carex rostrata to changes in the availability of nitrogen. Special attention is paid to soluble sugars ant free amino acids, which may control partitioning of biomass. (10 refs.)

Carbon-nitrogen interactions and biomass partitioning of Carex rostrata grown at three levels of nitrogen supply

Energy Technology Data Exchange (ETDEWEB)

Saarinen, T. [Helsinki Univ. (Finland). Dept. of Ecology and Systematics

1996-12-31

Biomass and production of vascular plants constitutes a major source of carbon input in peatlands. As rates of decomposition vary considerably with depth, the vertical distribution of biomass may substantially affect accumulation of carbon in peatlands. Therefore, allocation patterns between shoot and roots are particularly important when considering carbon balance of peatland ecosystems. The stimulatory effect of increasing atmospheric concentration of CO{sub 2} or photosynthesis may increase availability of carbon to most C3 plants. Availability of nitrogen may also alter both due to increased atmospheric deposition and changer in mineralisation rates associated with climate change. Most root-shoot partitioning models predict that allocation of biomass is dependent of the availability and uptake of carbon and nitrogen. A decrease in supply of carbon would favour allocation to shoots and a decrease in supply of nitrogen would increase allocation to roots. At a cellular level, non structural carbohydrates and free amino acids are thought to represent the biochemically available fraction of carbon and nitrogen, respectively. The aim of this work is study the long-term growth responses of Carex rostrata to changes in the availability of nitrogen. Special attention is paid to soluble sugars ant free amino acids, which may control partitioning of biomass. (10 refs.)

Remote sensing of nitrogen and water stress in wheat

NARCIS (Netherlands)

Tilling, A.K.; O'Leary, G.J.; Ferwerda, J.G.; Jones, S.D.; Fitzgerald, G.J.; Rodriguez, D.; Belford, R.

2007-01-01

Nitrogen (N) is the largest agricultural input in many Australian cropping systems and applying the right amount of N in the right place at the right physiological stage is a significant challenge for wheat growers. Optimizing N uptake could reduce input costs and minimize potential off-site

Factors influencing the in vitro uptake of mercury vapour in blood

Energy Technology Data Exchange (ETDEWEB)

Kudsk, F.N.

1969-01-01

The influence of a number of factors on the in vitro uptake of mercury vapour in blood has been investigated in order to clarify the mechanism by which mercury is oxidized in blood. The rate of mercury uptake in blood in a pure oxygen atmosphere is moderately increased, but somewhat decreased in a nitrogen atmosphere when compared with the rate of uptake in an atmospheric air phase. Increasing concentrations of methylene blue induce a very pronounced acceleration of the rate of mercury uptake in blood up to a maximum of about 10 times the normal uptake in an atmospheric air phase. Menadione shows a similar, but even more pronounced effect. The menadione-stimulated uptake is markedly inhibited by low concentrations of ethyl alcohol. Concentrations of potassium cyanide from 1/8 x 10/sup -3/ to 4 x 10/sup -3/ M cause a progressive inhibition of the mercury uptake in the blood up to a maximum of about 60%, which is very similar to the effect produced by ethyl alcohol. The investigations point to hydrogen peroxide and oxidized glutathione as agents of importance in the oxidation and uptake of mercury vapour in blood. The way in which ethyl alcohol inhibits the uptake is still unknown. Some possible mechanisms are discussed. 24 references, 4 figures, 3 tables.

Nitrogen acquisition, transport and metabolism in intact ectomycorrhizal associations studied by 15N stable isotope techniques

International Nuclear Information System (INIS)

Ek, H.

1993-05-01

The focus of this thesis is on the external mycelium and its role in nitrogen uptake, assimilation and translocation. Tree seedlings in association with ectomycorrhizal fungi were grown in observation chambers. The fungal mycelium were fed with 15-N ammonium or 15-N nitrate or a combination of both. The effects of Collembola on the ectomycorrhizal symbiosis were also studied. The results demonstrates an important role of the external mycelium of Paxillus involutus not only in the uptake but also in the assimilation of ammonium into a variety of different amino acids, primarily glutamine but also glutamic acid, aspartic acid, and alanine, immediately after uptake. The results indicate that ammonium is assimilated by GS and GOGAT or GDH in the mycelium at the uptake site. When nitrate was added to the mycelium as the sole nitrogen source nitrate was reduced in the mycelium and the product assimilated into amino acids. When ammonium nitrate was supplied to the fungal mycelium nitrate was taken up the fungus and transferred to the plant, however, apparently no assimilation of nitrate occurred in the external mycelium. Ammonium or an assimilation product, such as glutamine, probably represses nitrate reductase (NR) but not nitrate uptake and transfer in P. involutus. P. involutus nitrogen uptake and transfer to the associated mycorrhizal pine was up to 76% higher when low numbers of the Collembola Onychiurus armatus were present compared to when they were completely absent. This was probably an indirect effect as P. involutus hyphal growth rate and extramatrical biomass increased at a low Collembola density. At high Collembola densities P. involutus hyphal growth rate was retarded. (74 refs.)

In Situ One-Step Synthesis of Hierarchical Nitrogen-Doped Porous Carbon for High Performance Supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Jeon, Ju Won [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Texas A & M Univ., College Station, TX (United States); Sharma, Ronish [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Meduri, Praveen [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Arey, Bruce W. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Schaef, Herbert T. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Lutkenhaus, Jodie [Texas A & M Univ., College Station, TX (United States); Lemmon, John P. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Thallapally, Praveen K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Nandasiri, Manjula I. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); McGrail, B. Peter [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Nune, Satish K. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

2014-04-30

Electrochemical performance of the existing state-of-the art capacitors is not very high, key scientific barrier is that its charge storage mechanism wholly depends on adsorption of electrolyte on electrode. We present a novel method for the synthesis of nitrogen -doped porous carbons and address the drawback by precisely controlling composition and surface area. Nitrogen-doped porous carbon was synthesized using a self-sacrificial template technique without any additional nitrogen and carbon sources. They exhibited exceptionally high capacitance (239 Fg-1) due to additional pseudocapacitance originating from doped nitrogen. Cycling tests showed no obvious capacitance decay even after 10,000 cycles, which meets the requirement of commercial supercapacitors. Our method is simple and highly efficient for the production of large quantities of nitrogen-doped porous carbons.

Uptake of low density lipoproteins by the hamster lung. Interactions with capillary endothelium

International Nuclear Information System (INIS)

Nistor, A.; Simionescu, M.

1986-01-01

The mechanism by which the circulating low density lipoproteins (LDL) contribute to the lung surfactant cholesterol was investigated by perfusing the hamster lung in situ with LDL either radiolabeled or coupled to gold, or both. Part of [ 125 I]-LDL and [ 3 H]-cholesterol LDL were taken up by a specific process which was time- and concentration-dependent and reached saturation within 20 to 30 min of perfusion. Competition experiments and removal of receptor-bound LDL by heparin suggested that about 50% of LDL uptake is receptor-independent. Experiments using double labeled LDL showed a preferential uptake of 3 H-cholesterol versus 125 I by the lung both in situ and in vivo. LDL-gold particles (LDL-Au), recirculated through the isolated lung, bound to the endothelial luminal plasma membrane and to features potentially involved in receptor-mediated endocytosis (coated pits, coated vesicles, lysosomelike structures) and in transcytosis (plasmalemmal vesicles). The results suggest that LDL uptake by the lung takes place by both receptor-mediated and receptor-independent mechanisms. Cholesterol may be in part transferred to the lung without the apoprotein moiety; the alveolar capillary endothelium appears to be the first monitor of this complex process

Use of Bio-Organic Fertilizers to Develop N Uptake Using 15N Technique

International Nuclear Information System (INIS)

Galal, Y.G.M.

2008-01-01

Experimental work either in field scale or in green house conditions were conducted using 15 N technique to evaluate the role of different bio fertilizers and different plant residues as organic amendments on enhancement of plant N nutrition. Nitrogen fixation by a symbiotic bacteria has been observed in greenhouse and field experiments under dry land cropping systems. Biological N 2 fixation associated with crop residues (legumes or cereals) was investigated in pot experiments with wheat and chickpea cultivars. In these experiments, labelled wheat and rice straw were used as organic N sources in comparison with either 15 N-labelled ammonium sulfate or ammonium nitrate as chemical nitrogen fertilizers. Rhizobium inoculation extended to be used with wheat gave the best results of N uptake and N 2 fixation when combined with Azospirillum brasilense as heterotrophic diazotrophs. The nitrogen uptake by wheat plants was significantly increased by application of soybean residues and inoculation with Azospirillum brasilense. From the field trial we can conclude that soybean residue as enriched N material, and Azospirillum brasilense inoculation enhanced N yields of wheat cultivars grown in poor fertile sandy soil

Studies on nitrogen metabolism of soybean plants, (4)

International Nuclear Information System (INIS)

Kato, Yasumasa; Kitada, Subaru

1979-01-01

Nitrogen that came from cotyledons and nitrogen ( 15 N) pulse-fed at 5 different times during the growth of young soybean plants were studied for 33-days after germination. Cotyledons furnished nitrogen to primary leaves, stems, and roots for the first 8 days, but thereafter principally to 1 st and 2 nd trifoliate leaves. Redistribution of the cotyledon-derived nitrogen from primary leaves commenced from the 14 th day after germination when their total nitrogen was still increasing. At the end of the experiment, the cotyledon-derived nitrogen was distributed approximately uniformly among 6 expanded leaves, and very small amount was found in 3 immature leaves. It was shown that soybean leaves took up 15 N (via roots) throughout the entire period of their life, and from their near-mature stage onwards, uptake and redistribution of nitrogen were observed simultaneously. Thus, the nitrogen in mature leaves was partially being renewed constantly. Considering this fact, the nitrogen supplying capacity of soybean leaves was estimated to be about two times as large as that estimated conventionally from the net loss of nitrogen during their senescence. The turnover of leaf nitrogen was closely related to the turnover of leaf protein. Influx of nitrogen was invariably accompanied by the simultaneous synthesis of leaf protein, and conversely, efflux by the simultaneous breakdown of leaf protein. Sink removal (topping treatment) prevented the breakdown of leaf protein (as measured from the rate of release of label after the pulse feeding) as well as the export of nitrogen from the leaves. The nitrogen supplying function of soybean leaves was discussed in relation to the nitrogen and protein turnover of leaves. (Kaihara, S.)

The importance of cytosolic glutamine synthetase in nitrogen assimilation and recycling

Energy Technology Data Exchange (ETDEWEB)

Bernard, S.M.; Habash, D.Z.

2009-07-02

Glutamine synthetase assimilates ammonium into amino acids, thus it is a key enzyme for nitrogen metabolism. The cytosolic isoenzymes of glutamine synthetase assimilate ammonium derived from primary nitrogen uptake and from various internal nitrogen recycling pathways. In this way, cytosolic glutamine synthetase is crucial for the remobilization of protein-derived nitrogen. Cytosolic glutamine synthetase is encoded by a small family of genes that are well conserved across plant species. Members of the cytosolic glutamine synthetase gene family are regulated in response to plant nitrogen status, as well as to environmental cues, such as nitrogen availability and biotic/abiotic stresses. The complex regulation of cytosolic glutamine synthetase at the transcriptional to post-translational levels is key to the establishment of a specific physiological role for each isoenzyme. The diverse physiological roles of cytosolic glutamine synthetase isoenzymes are important in relation to current agricultural and ecological issues.

Carbon amendment stimulates benthic nitrogen cycling during the bioremediation of particulate aquaculture waste

Science.gov (United States)

Robinson, Georgina; MacTavish, Thomas; Savage, Candida; Caldwell, Gary S.; Jones, Clifford L. W.; Probyn, Trevor; Eyre, Bradley D.; Stead, Selina M.

2018-03-01

The treatment of organic wastes remains one of the key sustainability challenges facing the growing global aquaculture industry. Bioremediation systems based on coupled bioturbation-microbial processing offer a promising route for waste management. We present, for the first time, a combined biogeochemical-molecular analysis of the short-term performance of one such system that is designed to receive nitrogen-rich particulate aquaculture wastes. Using sea cucumbers (Holothuria scabra) as a model bioturbator we provide evidence that adjusting the waste C : N from 5 : 1 to 20 : 1 promoted a shift in nitrogen cycling pathways towards the dissimilatory nitrate reduction to ammonium (DNRA), resulting in net NH4+ efflux from the sediment. The carbon amended treatment exhibited an overall net N2 uptake, whereas the control receiving only aquaculture waste exhibited net N2 production, suggesting that carbon supplementation enhanced nitrogen fixation. The higher NH4+ efflux and N2 uptake was further supported by meta-genome predictions that indicate that organic-carbon addition stimulated DNRA over denitrification. These findings indicate that carbon addition may potentially result in greater retention of nitrogen within the system; however, longer-term trials are necessary to determine whether this nitrogen retention is translated into improved sea cucumber biomass yields. Whether this truly constitutes a remediation process is open for debate as there remains the risk that any increased nitrogen retention may be temporary, with any subsequent release potentially raising the eutrophication risk. Longer and larger-scale trials are required before this approach may be validated with the complexities of the in-system nitrogen cycle being fully understood.

Roostocks/Scion/Nitrogen Interactions Affect Secondary Metabolism in the Grape Berry

OpenAIRE

Habran, Aude; Commisso, Mauro; Helwi, Pierre; Hilbert, Ghislaine; Negri, Stefano; Ollat, Nathalie; Gom?s, Eric; van Leeuwen, Cornelis; Guzzo, Flavia; Delrot, Serge

2016-01-01

ABSTRACT : The present work investigates the interactions between soil content, rootstock and scion by focusing on the effects of roostocks and nitrogen supply on grape berry content. Scions of Cabernet Sauvignon (CS) and Pinot Noir (PN) varieties were grafted either on Riparia Gloire de Montpellier (RGM) or 110 Richter (110R) rootstock. The 4 rooststock/scion combinations were fertilized with 3 different levels of nitrogen after fruit set. Both in 2013 and 2014, N supply increased N uptake ...

Response of Pearl Millet to nitrogen as affected by water deficit

OpenAIRE

Diouf , O.; Brou , Yao Télesphore; Diouf , M.; Sarr , B.; Eyletters , M.; Roy-Macauley , H.; Delhaye , J.

2004-01-01

International audience; In the Sahelian zone, low soil N could be as limiting as drought in pearl millet production. Although growth and crop productivity depend on several biochemical reactions in which the nitrogen metabolism plays a great role, there is little information available on how N uptake and key enzymes, nitrate reductase and glutamine synthetase, are affected by nitrogen and water interaction in millet. For this purpose, the millet variety cv. Souna III was grown in the field du...

Nitrogen dynamics model for a pilot field-scale novel dewatered alum sludge cake-based constructed wetland system.

Science.gov (United States)

Kumar, J L G; Zhao, Y Q; Hu, Y S; Babatunde, A O; Zhao, X H

2015-01-01

A model simulating the effluent nitrogen (N) concentration of treated animal farm wastewater in a pilot on-site constructed wetland (CW) system, using dewatered alum sludge cake (DASC) as wetland substrate, is presented. The N-model was developed based on the Structural Thinking Experiential Learning Laboratory with Animation software and is considering organic nitrogen, ammonia nitrogen (NH3) and nitrate nitrogen (NO3-N) as the major forms of nitrogen involved in the transformation chains. Ammonification (AMM), ammonia volatilization, nitrification (NIT), denitrification, plant uptake, plant decaying and uptake of inorganic nitrogen by algae and bacteria were considered in this model. pH, dissolved oxygen, temperature, precipitation, solar radiation and nitrogen concentrations were considered as forcing functions in the model. The model was calibrated by observed data with a reasonable agreement prior to its applications. The simulated effluent detritus nitrogen, NH4-N, NO3-N and TN had a considerably good agreement with the observed results. The mass balance analysis shows that NIT accounts for 65.60%, adsorption (ad) (11.90%), AMM (8.90%) followed by NH4-N (Plants) (5.90%) and NO3-N (Plants) (4.40%). The TN removal was found 52% of the total influent TN in the CW. This study suggested an improved overall performance of a DASC-based CW and efficient N removal from wastewater.

Isotopic and enzymatic analyses of planktonic nitrogen utilisation in the vicinity of Cape Sines (Portugal) during weak upwelling activity

Science.gov (United States)

Slawyk, Gerd; Coste, Bernard; Collos, Yves; Rodier, Martine

1997-01-01

Using measurements of 15N uptake and activities of nitrate reductase and glutamine synthetase, the utilization of nitrogenous nutrients by microplankton in the Portuguese upwelling area was investigated. During this cruise the euphotic zone of coastal waters was in most cases bisected by a nitracline forming two layers. Total inorganic nitrogen uptake rates (NH 4+ + NO 3-) in the upper mixed and nitrate-impoverished layer ranged from 0.1 to 0.8 nM h -1 and were primarily supported by regenerated (ammonium) nitrogen (62-97%), whereas they varied between 0.9 and 10.4 nM h -1 in the deep nitrate-rich layer and were mainly driven by new (nitrate) nitrogen (52-82%). Depth profiles of Chl a-specific uptake rates for ammonium and nitrate paralleled those of absolute uptake rates, i.e. values of VNH 4+Chl were highest (up to 16.1 nmol μg -1 h -1) in nitrate-poor surface waters while values of VNO 3-Chl were maximum (up to 8.4 nmol μg -1 h -1)within the nitracline. This latter vertical ordering of planktonic nitrogen nutrition was consistent with an aged upwelling situation. However, applying several indices of cell metabolism and nutritional status, such as 15N uptake/enzyme activity, surge uptake internally controlled uptake, and V maxChl/K t ratios, we were able to demonstrate that the phytoplankton assemblages inhabiting the nutrient-impoverished upper layer still bore the signature of physically mediated nitrogen (nitrate) supply generated by active upwelling that had occurred during the week before our visit to the area. This signature was the most evident in samples from the station furthest inshore and faded with distance from shore as a result of the deepening of the nitrate isopleths (weakening of upwelling activity), which showed the same offshore trend. The appearance of nitrate-rich waters at the surface, after a strong pulse of upwelling favourable winds just before the end of the cruise, led to a five-fold increase in average (over the euphotic zone

Study of uptake and endocytosis of gamma rays-irradiated crotoxin by mice peritoneal macrophages

International Nuclear Information System (INIS)

Cardi, Bruno Andrade

1999-01-01

The purpose was to investigate the uptake and endocytosis of 2000 Gy 60 Co irradiated crotoxin through mouse peritoneal macrophages, correlating with native one and another non related protein, the ovalbumin. Native (CTXN) or 2000 Gy 60 Co γ-rays (dose rate 540 Gy/hour) irradiated crotoxin (CTXI) or ovalbumin processed of same manner (OVAN - OVAI) were offered to mouse peritoneal macrophages and their uptake was evaluated by immunohistochemistry and quantitative in situ ELISA. The involvement of scavenger receptors (ScvR) was evaluated by using blockers drugs (Probuco-PBC or Dextran Sulfate - SD) or with nonspecific blocking using fetal calf serum (FBS). The morphology and viability of macrophages were preserved during the experiments. CTXI showed irradiation-induced aggregates and formation of oxidative changing were observed on this protein after gamma rays treatment. By immunohistochemistry we could observe heavy stained phagocytic vacuole on macrophages incubated with CTXI, as compared with CTXN. Quantitatively by in situ ELISA, the sema pattern was observed, displaying a 2-fold CTXI incorporation. In presence of PBC or SD we could find a significant decrease of CTXI uptake but not of CTXN. However the CTXN uptake was depressed by FBS, not observed with CTXI. OVA, after gamma rays treatment, underwent a high degradation suffering a potent incorporation and metabolism by macrophages, with a major uptake of OVAI in longer incubation (120 minutes). Gamma rays ( 60 Co) produced oxidative changes on CTX molecule, leading to a uptake by ScvR-mice peritoneal macrophages, suggesting that the relation antigen-presenting cells and gamma rays-modified proteins are responsible for the better immune response presented by irradiated antigens. (author)

Effect of Biofertilizers on Macro and Micro Nutrients Uptake and Essential Oil Content in Dracocephalum moldavica L.

Directory of Open Access Journals (Sweden)

S Rahimzadeh

2013-08-01

Full Text Available In order to investigation the effect of different fertilization treatments on nutrient and essential oil contents in dragonhead drug (Dracocephalum moldavica L., an experiment was conducted in the station of agricultural research in Urmia on 2008. Treatments (nitroxin, barvar phosphate biofertilizer, biosulfur, nitroxin+ barvar phosphate biofertilizer, barvar phosphate biofertilizer + biosulfur, nitroxin+ biosulfur, nitroxin+ barvar phosphate biofertilizer + biosulfur, chemical fertilizer, control were arranged based on randomized complete block design with 4 replications. Results indicated that uptake of Nitrogen, Phosphorus, Potassium, Iron, Copper, Manganese and essential oil content were affected by studied treatments significantly but uptake of zinc by plant was not affected. Means comparison showed the highest values of Nitrogen (3.55%, Potassium (3.47% and Iron (4.56 ppm in Nitroxin treatment, Phosphorus (0.26% and Copper (0.33 ppm in barvar phosphate biofertilizer + biosulfur treatment, Manganese (0.48 ppm in chemical origin of nitrogen+phosphorus+ potassium treatment and essential oil content (0.48% in nitroxin+ barvar phosphate biofertilizer + biosulfur treatment

Efficacy monitoring of in situ fuel bioremediation

International Nuclear Information System (INIS)

Mueller, J.; Borchert, S.; Heard, C.

1996-01-01

The wide-scale, multiple-purpose use of fossil fuels throughout the industrialized world has resulted in the inadvertent contamination of myriad environments. Given the scope and magnitude of these environmental contamination problems, bioremediation often represents the only practical and economically feasible solution. This is especially true when depth of contamination, magnitude of the problem, and nature of contaminated material preclude other remedial actions, short of the no-response alternative. From the perspective, the effective, safe and scientifically valid use of in situ bioremediation technologies requires cost-efficient and effective implementation strategies in combination with unequivocal approaches for monitoring efficacy of performance. Accordingly, with support from the SERDP program, the authors are field-testing advanced in situ bioremediation strategies and new approaches in efficacy monitoring that employ techniques instable carbon and nitrogen isotope biogeochemistry. One field demonstration has been initiated at the NEX site in Port Hueneme, CA (US Navy's National Test Site). The objectives are: (1) to use stable isotopes as a biogeochemical monitoring tool for in situ bioremediation of refined petroleum (i.e., BTEX), and (2) to use vertical groundwater circulation technology to effect in situ chemical containment and enhanced in situ bioremediation

On the virtue of acid–base titrations for the determination of basic sites in nitrogen doped carbon nanotubes

NARCIS (Netherlands)

Bitter, J.H.; van Dommele, S.; de Jong, K.P.

2013-01-01

The basicity and nature of basic species in nitrogen containing carbon nanotubes (NCNT) prepared under different conditions were investigated by acid–base titrations. Proton uptake curves were derived from the titration data and were used to establish the basicity (pKa) ranges of nitrogen species

Invasive Andropogon gayanus (gamba grass) is an ecosystem transformer of nitrogen relations in Australian savanna.

Science.gov (United States)

Rossiter-Rachor, N A; Setterfield, S A; Douglas, M M; Hutley, L B; Cook, G D; Schmidt, S

2009-09-01

Invasion by the African grass Andropogon gayanus is drastically altering the understory structure of oligotrophic savannas in tropical Australia. We compared nitrogen (N) relations and phenology of A. gayanus and native grasses to examine the impact of invasion on N cycling and to determine possible reasons for invasiveness of A. gayanus. Andropogon gayanus produced up to 10 and four times more shoot phytomass and root biomass, with up to seven and 2.5 times greater shoot and root N pools than native grass understory. These pronounced differences in phytomass and N pools between A. gayanus and native grasses were associated with an altered N cycle. Most growth occurs in the wet season when, compared with native grasses, dominance of A. gayanus was associated with significantly lower total soil N pools, lower nitrification rates, up to three times lower soil nitrate availability, and up to three times higher soil ammonium availability. Uptake kinetics for different N sources were studied with excised roots of three grass species ex situ. Excised roots of A. gayanus had an over six times higher-uptake rate of ammonium than roots of native grasses, while native grass Eriachne triseta had a three times higher uptake rate of nitrate than A. gayanus. We hypothesize that A. gayanus stimulates ammonification but inhibits nitrification, as was shown to occur in its native range in Africa, and that this modification of the soil N cycle is linked to the species' preference for ammonium as an N source. This mechanism could result in altered soil N relations and could enhance the competitive superiority and persistence of A. gayanus in Australian savannas.

Assessing variable rate nitrogen fertilizer strategies within an extensively instrument field site using the MicroBasin model

Science.gov (United States)

Ward, N. K.; Maureira, F.; Yourek, M. A.; Brooks, E. S.; Stockle, C. O.

2014-12-01

The current use of synthetic nitrogen fertilizers in agriculture has many negative environmental and economic costs, necessitating improved nitrogen management. In the highly heterogeneous landscape of the Palouse region in eastern Washington and northern Idaho, crop nitrogen needs vary widely within a field. Site-specific nitrogen management is a promising strategy to reduce excess nitrogen lost to the environment while maintaining current yields by matching crop needs with inputs. This study used in-situ hydrologic, nutrient, and crop yield data from a heavily instrumented field site in the high precipitation zone of the wheat-producing Palouse region to assess the performance of the MicroBasin model. MicroBasin is a high-resolution watershed-scale ecohydrologic model with nutrient cycling and cropping algorithms based on the CropSyst model. Detailed soil mapping conducted at the site was used to parameterize the model and the model outputs were evaluated with observed measurements. The calibrated MicroBasin model was then used to evaluate the impact of various nitrogen management strategies on crop yield and nitrate losses. The strategies include uniform application as well as delineating the field into multiple zones of varying nitrogen fertilizer rates to optimize nitrogen use efficiency. We present how coupled modeling and in-situ data sets can inform agricultural management and policy to encourage improved nitrogen management.

Tropical Legume Crop Rotation and Nitrogen Fertilizer Effects on Agronomic and Nitrogen Efficiency of Rice

Directory of Open Access Journals (Sweden)

Motior M. Rahman

2014-01-01

Full Text Available Bush bean, long bean, mung bean, and winged bean plants were grown with N fertilizer at rates of 0, 2, 4, and 6 g N m−2 preceding rice planting. Concurrently, rice was grown with N fertilizer at rates of 0, 4, 8, and 12 g N m−2. No chemical fertilizer was used in the 2nd year of crop to estimate the nitrogen agronomic efficiency (NAE, nitrogen recovery efficiency (NRE, N uptake, and rice yield when legume crops were grown in rotation with rice. Rice after winged bean grown with N at the rate of 4 g N m−2 achieved significantly higher NRE, NAE, and N uptake in both years. Rice after winged bean grown without N fertilizer produced 13–23% higher grain yield than rice after fallow rotation with 8 g N m−2. The results revealed that rice after winged bean without fertilizer and rice after long bean with N fertilizer at the rate of 4 g N m−2 can produce rice yield equivalent to that of rice after fallow with N fertilizer at rates of 8 g N m−2. The NAE, NRE, and harvest index values for rice after winged bean or other legume crop rotation indicated a positive response for rice production without deteriorating soil fertility.

nitrogen saturation in stream ecosystems

OpenAIRE

Earl, S. R.; Valett, H. M.; Webster, J. R.

2006-01-01

The concept of nitrogen (N) saturation has organized the assessment of N loading in terrestrial ecosystems. Here we extend the concept to lotic ecosystems by coupling Michaelis-Menten kinetics and nutrient spiraling. We propose a series of saturation response types, which may be used to characterize the proximity of streams to N saturation. We conducted a series of short-term N releases using a tracer ((NO3)-N-15-N) to measure uptake. Experiments were conducted in streams spanning a gradient ...

Interactive Influence of N and P on their uptake by four different ...

African Journals Online (AJOL)

The uptake kinetics of nitrogen (N) and phosphorus (P) by hydrophytes can be influenced by the interaction between N and P. In this study, Pistia stratiotes (a floating plant), Eichhornia crassipes (a floating plant), Vallisneria spiralis (a submerged plant), and Cyperus papyrus (an emergent plant) were selected to measure ...

[Mechanisms for the increased fertilizer nitrogen use efficiency of rice in wheat-rice rotation system under combined application of inorganic and organic fertilizers].

Science.gov (United States)

Liu, Yi-Ren; Li, Xiang; Yu, Jie; Shen, Qi-Rong; Xu, Yang-Chun

2012-01-01

A pot experiment was conducted to study the effects of combined application of organic and inorganic fertilizers on the nitrogen uptake by rice and the nitrogen supply by soil in a wheat-rice rotation system, and approach the mechanisms for the increased fertilizer nitrogen use efficiency of rice under the combined fertilization from the viewpoint of microbiology. Comparing with applying inorganic fertilizers, combined application of organic and inorganic fertilizers decreased the soil microbial biomass carbon and nitrogen and soil mineral nitrogen contents before tillering stage, but increased them significantly from heading to filling stage. Under the combined fertilization, the dynamics of soil nitrogen supply matched best the dynamics of rice nitrogen uptake and utilization, which promoted the nitrogen accumulation in rice plant and the increase of rice yield and biomass, and increased the fertilizer nitrogen use efficiency of rice significantly. Combined application of inorganic and organic fertilizers also promoted the propagation of soil microbes, and consequently, more mineral nitrogen in soil was immobilized by the microbes at rice early growth stage, and the immobilized nitrogen was gradually released at the mid and late growth stages of rice, being able to better satisfy the nitrogen demand of rice in its various growth and development stages.

Simulation of irrigation and nitrogen fertilization management of maize under edaphic conditions of south of Havana

International Nuclear Information System (INIS)

Lopez Seijas, Teresa; Cid, G.; Gonzalez, F.; Jorge, Y.; Chaterlan, Y.; Giralt, E.; Rodriguez, R.; Duennas, G.

1999-01-01

The main objective of this work is to validate the crop simulation model STICS for the soil and climate conditions of south of Havana, especially for the water and nitrogen balances on Maize crop on Ferralitic soil, For this purpose was used all the available information from field experiments carried out in the Experimental Stations of the Irrigation and Drainage and Soil Research Institutes, both on south of Havana, The comparison between the simulation and observed values showed a good fitness for the variables related to the crop water uptake, while for the soil water content when the root water uptake flux is minimum and the soil water redistribution flux is maximum wasn't good, The soil nitrogen balance was adjusted from the optimization of the parameters related to the mineralization velocity of soil organic nitrogen, Nevertheless is necessary to complete this study involving other climate conditions and water and nitrogen managements to define the optimum strategy for irrigation and fertilization of Maize crop on the studied conditions,

Preparation and Gas Adsorption of Porous Materials from Molecular Precursors

DEFF Research Database (Denmark)

Hu, Xinming

with bimodal porosity are produced via cyclotrimerization of two aromatic tetranitriles and in situ carbonization in molten ZnCl2. The carbonization occurs by decomposition of triazine rings, which results in complete loss of nitrogen and formation of substantial mesopores. The resulting materials possess...... surface areas above 1200 m2 g−1 and exhibit exceptionally high H2 uptake (up to 2.34 wt% at 77 K and 1 bar) but low CO2 uptake capacity. In Chapter 4, a nitrogen-rich porous carbon is prepared via cyclotrimerization of a perfluorinated aromatic nitrile and in situ carbonization in molten ZnCl2......), and H2 (2.0 wt%, 77 K and 1.0 bar). Chapters 5, 6, and 7 deal with the construction of triazatriangulenium (TATA)-based ionic porous frameworks. A variety of polycondensation reactions have been applied, but only FeCl3-promoted oxidative polymerization of thiophene-/carbazolefunctionalized TATAs...

Effects of CO2 enrichment on photosynthesis, growth, and nitrogen metabolism of the seagrass Zostera noltii

Science.gov (United States)

Alexandre, Ana; Silva, João; Buapet, Pimchanok; Björk, Mats; Santos, Rui

2012-01-01

Seagrass ecosystems are expected to benefit from the global increase in CO2 in the ocean because the photosynthetic rate of these plants may be Ci-limited at the current CO2 level. As well, it is expected that lower external pH will facilitate the nitrate uptake of seagrasses if nitrate is cotransported with H+ across the membrane as in terrestrial plants. Here, we investigate the effects of CO2 enrichment on both carbon and nitrogen metabolism of the seagrass Zostera noltii in a mesocosm experiment where plants were exposed for 5 months to two experimental CO2 concentrations (360 and 700 ppm). Both the maximum photosynthetic rate (Pm) and photosynthetic efficiency (α) were higher (1.3- and 4.1-fold, respectively) in plants exposed to CO2-enriched conditions. On the other hand, no significant effects of CO2 enrichment on leaf growth rates were observed, probably due to nitrogen limitation as revealed by the low nitrogen content of leaves. The leaf ammonium uptake rate and glutamine synthetase activity were not significantly affected by increased CO2 concentrations. On the other hand, the leaf nitrate uptake rate of plants exposed to CO2-enriched conditions was fourfold lower than the uptake of plants exposed to current CO2 level, suggesting that in the seagrass Z. noltii nitrate is not cotransported with H+ as in terrestrial plants. In contrast, the activity of nitrate reductase was threefold higher in plant leaves grown at high-CO2 concentrations. Our results suggest that the global effects of CO2 on seagrass production may be spatially heterogeneous and depend on the specific nitrogen availability of each system. Under a CO2 increase scenario, the natural levels of nutrients will probably become limiting for Z. noltii. This potential limitation becomes more relevant because the expected positive effect of CO2 increase on nitrate uptake rate was not confirmed. PMID:23145346

Effects of CO(2) enrichment on photosynthesis, growth, and nitrogen metabolism of the seagrass Zostera noltii.

Science.gov (United States)

Alexandre, Ana; Silva, João; Buapet, Pimchanok; Björk, Mats; Santos, Rui

2012-10-01

Seagrass ecosystems are expected to benefit from the global increase in CO(2) in the ocean because the photosynthetic rate of these plants may be C(i)-limited at the current CO(2) level. As well, it is expected that lower external pH will facilitate the nitrate uptake of seagrasses if nitrate is cotransported with H(+) across the membrane as in terrestrial plants. Here, we investigate the effects of CO(2) enrichment on both carbon and nitrogen metabolism of the seagrass Zostera noltii in a mesocosm experiment where plants were exposed for 5 months to two experimental CO(2) concentrations (360 and 700 ppm). Both the maximum photosynthetic rate (P(m)) and photosynthetic efficiency (α) were higher (1.3- and 4.1-fold, respectively) in plants exposed to CO(2)-enriched conditions. On the other hand, no significant effects of CO(2) enrichment on leaf growth rates were observed, probably due to nitrogen limitation as revealed by the low nitrogen content of leaves. The leaf ammonium uptake rate and glutamine synthetase activity were not significantly affected by increased CO(2) concentrations. On the other hand, the leaf nitrate uptake rate of plants exposed to CO(2)-enriched conditions was fourfold lower than the uptake of plants exposed to current CO(2) level, suggesting that in the seagrass Z. noltii nitrate is not cotransported with H(+) as in terrestrial plants. In contrast, the activity of nitrate reductase was threefold higher in plant leaves grown at high-CO(2) concentrations. Our results suggest that the global effects of CO(2) on seagrass production may be spatially heterogeneous and depend on the specific nitrogen availability of each system. Under a CO(2) increase scenario, the natural levels of nutrients will probably become limiting for Z. noltii. This potential limitation becomes more relevant because the expected positive effect of CO(2) increase on nitrate uptake rate was not confirmed.

Achieving Lower Nitrogen Balance and Higher Nitrogen Recovery Efficiency Reduces Nitrous Oxide Emissions in North America's Maize Cropping Systems

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Rex A. Omonode

2017-06-01

Full Text Available Few studies have assessed the common, yet unproven, hypothesis that an increase of plant nitrogen (N uptake and/or recovery efficiency (NRE will reduce nitrous oxide (N2O emission during crop production. Understanding the relationships between N2O emissions and crop N uptake and use efficiency parameters can help inform crop N management recommendations for both efficiency and environmental goals. Analyses were conducted to determine which of several commonly used crop N uptake-derived parameters related most strongly to growing season N2O emissions under varying N management practices in North American maize systems. Nitrogen uptake-derived variables included total aboveground N uptake (TNU, grain N uptake (GNU, N recovery efficiency (NRE, net N balance (NNB in relation to GNU [NNB(GNU] and TNU [NNB(TNU], and surplus N (SN. The relationship between N2O and N application rate was sigmoidal with relatively small emissions for N rates <130 kg ha−1, and a sharp increase for N rates from 130 to 220 kg ha−1; on average, N2O increased linearly by about 5 g N per kg of N applied for rates up to 220 kg ha−1. Fairly strong and significant negative relationships existed between N2O and NRE when management focused on N application rate (r2 = 0.52 or rate and timing combinations (r2 = 0.65. For every percentage point increase, N2O decreased by 13 g N ha−1 in response to N rates, and by 20 g N ha−1 for NRE changes in response to rate-by-timing treatments. However, more consistent positive relationships (R2 = 0.73–0.77 existed between N2O and NNB(TNU, NNB(GNU, and SN, regardless of rate and timing of N application; on average N2O emission increased by about 5, 7, and 8 g N, respectively, per kg increase of NNB(GNU, NNB(TNU, and SN. Neither N source nor placement influenced the relationship between N2O and NRE. Overall, our analysis indicated that a careful selection of appropriate N rate applied at the right time can both increase NRE and reduce N

Effects of elevated CO2 on soil organic matter turnover and plant nitrogen uptake: First results from a dual labeling mesocosm experiment

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Eder, Lucia Muriel; Weber, Enrico; Schrumpf, Marion; Zaehle, Sönke

2017-04-01

The response of plant growth to elevated concentrations of CO2 (eCO2) is often constrained by plant nitrogen (N) uptake. To overcome potential N limitation, plants may invest photosynthetically fixed carbon (C) into N acquiring strategies, including fine root biomass, root exudation, or C allocation to mycorrhizal fungi. In turn, these strategies may affect the decomposition of soil organic matter, leading to uncertainties in net effects of eCO2 on C storage. To gain more insight into these plant-soil C-N-interactions, we combined C and N stable isotope labeling in a mesocosm experiment. Saplings of Fagus sylvatica L. were exposed to a 13CO2 enriched atmosphere at near ambient (380 ppm) or elevated (550 ppm) CO2 concentrations for four months of the vegetation period in 2016. Aboveground and belowground net CO2 fluxes were measured separately and the 13C label enabled partitioning of total soil CO2 efflux into old, soil derived and new, plant-derived C. We used ingrowth cores to assess effects of eCO2on belowground C allocation and plant N uptake in more detail and in particular we evaluated the relative importance of ectomycorrhizal associations. In the soil of each sapling, ingrowth cores with different mesh sizes allowed fine roots or only mycorrhizal hyphae to penetrate. In one type of ingrowth core each, we incorporated fine root litter that was enriched in 15N. Additionally, total N uptake was estimated by using 15N enriched saplings and unlabeled control plants. We found that eCO2 increased aboveground net CO2 exchange rates by 19% and total soil respiration by 11%. The eCO2 effect for GPP and also for NPP was positive (+23% and +11%, respectively). By combining gaseous C fluxes with data on new and old C stocks in bulk soil and plants through destructive harvesting in late autumn 2016, we will be able to infer net effects of eCO2 on the fate of C in these mesocosms. Biomass allocation patterns can reveal physiological responses to high C availability under

Understanding Plant Nitrogen Metabolism through Metabolomics and Computational Approaches

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Perrin H. Beatty

2016-10-01

Full Text Available A comprehensive understanding of plant metabolism could provide a direct mechanism for improving nitrogen use efficiency (NUE in crops. One of the major barriers to achieving this outcome is our poor understanding of the complex metabolic networks, physiological factors, and signaling mechanisms that affect NUE in agricultural settings. However, an exciting collection of computational and experimental approaches has begun to elucidate whole-plant nitrogen usage and provides an avenue for connecting nitrogen-related phenotypes to genes. Herein, we describe how metabolomics, computational models of metabolism, and flux balance analysis have been harnessed to advance our understanding of plant nitrogen metabolism. We introduce a model describing the complex flow of nitrogen through crops in a real-world agricultural setting and describe how experimental metabolomics data, such as isotope labeling rates and analyses of nutrient uptake, can be used to refine these models. In summary, the metabolomics/computational approach offers an exciting mechanism for understanding NUE that may ultimately lead to more effective crop management and engineered plants with higher yields.

Exogenous Glycine Nitrogen Enhances Accumulation of Glycosylated Flavonoids and Antioxidant Activity in Lettuce (Lactuca sativa L.)

OpenAIRE

Xiao Yang; Xiaoxian Cui; Xiaoxian Cui; Li Zhao; Doudou Guo; Lei Feng; Shiwei Wei; Chao Zhao; Chao Zhao; Danfeng Huang

2017-01-01

Glycine, the simplest amino acid in nature and one of the most abundant free amino acids in soil, is regarded as a model nutrient in organic nitrogen studies. To date, many studies have focused on the uptake, metabolism and distribution of organic nitrogen in plants, but few have investigated the nutritional performance of plants supplied with organic nitrogen. Lettuce (Lactuca sativa L.), one of the most widely consumed leafy vegetables worldwide, is a significant source of antioxidants and ...

Solar thermal evaporation of human urine for nitrogen and phosphorus recovery in Vietnam

International Nuclear Information System (INIS)

Antonini, Samantha; Nguyen, Phong Thanh; Arnold, Ute; Eichert, Thomas; Clemens, Joachim

2012-01-01

A No Mix sanitation system was installed in a dormitory at the University of Can Tho in Vietnam, with the objective of recycling nutrients from source separated urine. This paper presents a pilot scale evaporation technology, and investigates the feasibility of recovering nitrogen and phosphorus from human urine by solar still for use as fertilizer. After 26 days of sun exposure, 360 g of solid fertilizer material was recovered from 50 L undiluted urine. This urine-derived fertilizer was mainly composed of sodium chloride, and had phosphorus and nitrogen contents of almost 2%. When tested with maize and ryegrass, the urine fertilizer led to biomass yields and phosphorus and nitrogen uptakes comparable to those induced by a commercial mineral fertilizer. Urine acidification with sulfuric or phosphoric acid prior treatment reduced nitrogen losses, improved the nutrient content of the generated fertilizers, and induced higher biomass yields and nitrogen and phosphorus uptakes than the commercial mineral fertilizer. However, acidification is not recommended in developing countries due to additional costs and handling risks. The fate of micropollutants and the possibility of separating sodium chloride from other beneficial nutrients require further investigation. - Highlights: ► 360 g of fertilizer was derived from 50 L urine by solar evaporative distillation. ► The fertilizer contained 90% sodium chloride, 3% sulfur, 2% nitrogen, 2% phosphorus. ► It induced biomass yields comparable to those produced by a commercial fertilizer. ► Urine acidification improved the nutrient content of the generated fertilizers. ► Acidification is not recommended for use in developing countries (costs, safety).

GlnR-mediated regulation of nitrogen metabolism in the actinomycete Saccharopolyspora erythraea.

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Yao, Li-Li; Liao, Cheng-Heng; Huang, Gang; Zhou, Ying; Rigali, Sebastien; Zhang, Buchang; Ye, Bang-Ce

2014-09-01

Nitrogen source sensing, uptake, and assimilation are central for growth and development of microorganisms which requires the participation of a global control of nitrogen metabolism-associated genes at the transcriptional level. In soil-dwelling antibiotic-producing actinomycetes, this role is played by GlnR, an OmpR family regulator. In this work, we demonstrate that SACE_7101 is the ortholog of actinomycetes' GlnR global regulators in the erythromycin producer Saccharopolyspora erythraea. Indeed, the chromosomal deletion of SACE_7101 severely affects the viability of S. erythraea when inoculated in minimal media supplemented with NaNO3, NaNO2, NH4Cl, glutamine, or glutamate as sole nitrogen source. Combination of in silico prediction of cis-acting elements, subsequent in vitro (through gel shift assays) and in vivo (real-time reverse transcription polymerase chain reaction) validations of the predicted target genes revealed a very large GlnR regulon aimed at adapting the nitrogen metabolism of S. erythraea. Indeed, enzymes/proteins involved in (i) uptake and assimilation of ammonium, (ii) transport and utilization of urea, (iii) nitrite/nitrate, (iv) glutamate/glutamine, (v) arginine metabolism, (vi) nitric oxide biosynthesis, and (vii) signal transduction associated with the nitrogen source supplied have at least one paralog gene which expression is controlled by GlnR. Our work highlights a GlnR-binding site consensus sequence (t/gna/cAC-n6-GaAAc) which is similar although not identical to the consensus sequences proposed for other actinomycetes. Finally, we discuss the distinct and common features of the GlnR-mediated transcriptional control of nitrogen metabolism between S. erythraea and the model organism Streptomyces coelicolor.

Nutritional and water effect on fluoride uptake and respiration of bean seedlings. [Phaseolus vulgaris

Energy Technology Data Exchange (ETDEWEB)

Applegate, H G; Adams, D F

1960-01-01

Bean plants (Phaseolus vulgaris) were grown in an atmosphere containing 2.0 +/- 0.21 g F /mT (1.6 ppb). The effect of N, P, K, Fe, and Ca deficiencies and the effect of osmotic pressures of 0, 1.5, 3.0, 4.5, 6.0 and 7.5 pounds on fluoride uptake and fluoride-mediated respiration were studied. The data showed that P deficient plants took up more fluoride than plants deficient in any of the other elements studied. Fluoride-mediated respiration was phosphorous dependent, however. Plants low in Fe or K showed increased uptake of fluoride. Nitrogen had no effect on fluoride uptake under the conditions of this experiment. Plants low in Fe showed inhibition of oxygen uptake. This inhibition was accentuated by fluoride. The interactions of N, K and Ca with fluoride on respiration were complex. Neither fluoride uptake nor fluoride-mediated respiration appeared to be linked directly to the water economy of the plants. 14 references, 6 tables.

Ultraviolet-B radiation effects on inorganic nitrogen uptake by natural assemblages of oceanic plankton

International Nuclear Information System (INIS)

Behrenfeld, M.J.; Lean, D.R.S.; Lee, H. II

1995-01-01

Ultraviolet-B radiation (UVBR: 290-320 nm) inhibited ammonium uptake (ρ NH4 ) and nitrate uptake (ρ NO3 ) in natural plankton assemblages collected during a transect from 37 degrees N to 55 degrees N in the Pacific Ocean. Comparison of responses in ρ NH4 to ambient solar- and lamp-enhanced UVBR spectra allowed calculation of an action spectrum for ρ NH4 inhibition. The slope of the action spectrum for ρ NH4 is half as steep as action spectra for UVBR inhibition of photosynthetic carbon uptake. Consequently, UVBR-induced photoinhibition of ρ NH4 extends to greater depths than inhibition of carbon fixation due to the greater relative effect of longer UVBR wavelengths. Inhibition of ρ NH4 was dependent upon UVBR dose when doses were weighted by the ρ NH4 action spectrum. Dependence of UVBR inhibition of ρ NH4 on dose rate was not apparent. We found that near-surface ρ NH4 and ρ NO3 can be overestimated in excess of 50% when measured using standard incubation vessels made of UVBR-absorbing materials such as polycarbonate. 68 refs., 9 figs., 1 tab

pOsNAR2.1:OsNAR2.1 expression enhances nitrogen uptake efficiency and grain yield in transgenic rice plants.

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Chen, Jingguang; Fan, Xiaoru; Qian, Kaiyun; Zhang, Yong; Song, Miaoquan; Liu, Yu; Xu, Guohua; Fan, Xiaorong

2017-10-01

The nitrate (NO3-) transporter has been selected as an important gene maker in the process of environmental adoption in rice cultivars. In this work, we transferred another native OsNAR2.1 promoter with driving OsNAR2.1 gene into rice plants. The transgenic lines with exogenous pOsNAR2.1:OsNAR2.1 constructs showed enhanced OsNAR2.1 expression level, compared with wild type (WT), and 15 N influx in roots increased 21%-32% in response to 0.2 mm and 2.5 mm 15NO3- and 1.25 mm 15 NH 4 15 NO 3 . Under these three N conditions, the biomass of the pOsNAR2.1:OsNAR2.1 transgenic lines increased 143%, 129% and 51%, and total N content increased 161%, 242% and 69%, respectively, compared to WT. Furthermore in field experiments we found the grain yield, agricultural nitrogen use efficiency (ANUE), and dry matter transfer of pOsNAR2.1:OsNAR2.1 plants increased by about 21%, 22% and 21%, compared to WT. We also compared the phenotypes of pOsNAR2.1:OsNAR2.1 and pOsNAR2.1:OsNRT2.1 transgenic lines in the field, found that postanthesis N uptake differed significantly between them, and in comparison with the WT. Postanthesis N uptake (PANU) increased approximately 39% and 85%, in the pOsNAR2.1:OsNAR2.1 and pOsNAR2.1:OsNRT2.1 transgenic lines, respectively, possibly because OsNRT2.1 expression was less in the pOsNAR2.1:OsNAR2.1 lines than in the pOsNAR2.1:OsNRT2.1 lines during the late growth stage. These results show that rice NO 3 - uptake, yield and NUE were improved by increased OsNAR2.1 expression via its native promoter. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

Time-resolved investigation of the surface chemical modification of poly(ethylene naphthalate) by nitrogen plasma treatment

International Nuclear Information System (INIS)

Grace, J.M.; Zhuang, H.K.; Gerenser, L.J.; Freeman, D.R.

2003-01-01

A low rf nitrogen plasma source was used to treat poly(ethylene-2, 6-naphthalate) web material. Nitrogen uptake, the N 1s centroid, the N 1s peak width, rearrangement of the ester (from the O 1s spectrum), and oxygen level were measured using x-ray photoelectron spectroscopy as a function of treatment time at several treatment conditions. The observed changes in surface chemistry with treatment time are roughly consistent with a dose response having a linear regime at low doses and a saturation regime at high doses (where dose is power/width/web speed). Hence, to a first approximation, the flux densities (to the web) of relevant species scale with power. As the dose increases, the distribution of nitrogen groups formed broadens and shifts toward higher N 1s binding energy, suggesting that a larger fraction of the nitrogen-containing species are amines at low doses and amides at higher doses. The breadth of the distribution of nitrogen-containing species appears to be strongly correlated with the amount of nitrogen incorporated in the PEN surface. A surface sites model was applied to the measured nitrogen uptake as a function of treatment time. Phenomenological nitrogen incorporation and loss terms were determined in the context of this model. Both terms increase with treatment power and treatment pressure. The ratio, however, varies to a much smaller degree as a function of process conditions, with high powers and pressures giving the highest ratio. Further elucidation of the incorporation and loss processes should be possible with plasma diagnostic data related to species concentrations

Effects of biochar amendment and fertilizer sources on serrano chili pepper yield, uptake, and nitrogen fate

Science.gov (United States)

Efficient nitrogen (N) management strategies are a key approach in addressing the increase of food demand and environmental protection. Failing to achieve adequate nitrogen use efficiency (NUE) in agricultural systems can cause damaging outcomes including degradative water quality, increase in green...

Use efficiency of variable rate of nitrogen prescribed by optical sensor in corn

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Jardes Bragagnolo

2016-02-01

Full Text Available ABSTRACT The efficiency of nitrogen fertilizer in corn is usually low, negatively affecting plant nutrition, the economic return, and the environment. In this context, a variable rate of nitrogen, prescribed by crop sensors, has been proposed as an alternative to the uniform rate of nitrogen traditionally used by farmers. This study tested the hypothesis that variable rate of nitrogen, prescribed by optical sensor, increases the nitrogen use efficiency and grain yield as compared to uniform rate of nitrogen. The following treatments were evaluated: 0; 70; 140; and 210 kg ha-1 under uniform rate of nitrogen, and 140 kg ha -1 under variable rate of nitrogen. The nitrogen source was urea applied on the soil surface using a distributor equipped with the crop sensor. In this study, the grain yield ranged from 10.2 to 15.5 Mg ha-1, with linear response to nitrogen rates. The variable rate of nitrogen increased by 11.8 and 32.6% the nitrogen uptake and nitrogen use efficiency, respectively, compared to the uniform rate of nitrogen. However, no significant increase in grain yield was observed, indicating that the major benefit of the variable rate of nitrogen was reducing the risk of environmental impact of fertilizer.

Boreal bog plants: nitrogen sources and uptake of recently deposited nitrogen

International Nuclear Information System (INIS)

Nordbakken, J.F.; Ohlson, M.; Hoegberg, P.

2003-01-01

The main goals of this study were to determine the δ 15 N signature of quantitatively important boreal bog plants as basis for discussing their N sources, and to assess the effects of five different 3 year N treatments (i.e. 0, 5, 10, 20 and 40 kg N ha -1 year -1 ) on the bog plants and surface peat at different depths (i.e. 0, 5, 10, 20 and 40 cm) by using 15 N as tracer. Plants and peat were analyzed for N concentration, 15 N natural abundance and 15 N at.%. From the results we draw three main conclusions: First, the relative importance of different N sources is species-specific among bog plants. Second, an annual addition of 5 kg N ha -1 year -1 was sufficient to significantly increase the N concentration in Sphagnum mosses, liverworts and shallow rooted vascular plants, and an annual addition of 40 kg N ha -1 year -1 during 3 years was not sufficient to increase the N concentration in deep rooted plants, although the 15 N content increased continuously, indicating a possible longer term effect. Third, an annual addition of 40 kg N ha -1 year -1 during 3 years increased the N content in surface peat at depths of 5 and 10 cm, but not at depths of 20 and 40 cm, indicating the capacity of the living Sphagnum mosses and the surface peat to take up deposited N, and thereby function as a filter. - Living Sphagnum mosses and surface peat function as a filter for added nitrogen

[Nitrogen input altered testate amoebae community in peatland of Sanjiang Plain, Northeast China].

Science.gov (United States)

Song, Li-hong; Yan, Xiu-min; Wang, Ke-hong; Zhu, Xiao-yan; Wu, Dong-hu

2015-02-01

In the present study, an in situ control experiment was carried out to explore the response of testate amoebae to exogenous nitrogen addition in peatland of Sanjiang Plain. The results showed that nitrogen addition increased the biomass of testate amoebae at lower levels (6 g N · m(-2)), while decreased it at higher levels (> 12 g N · m(-2)). At genus level, nitrogen addition significantly increased the biomass of Arcella and Phryganella, decreased the biomass of Euglypha. Only lower nitrogen addition significantly increased the biomass of Centropyxis. At species level, nitrogen addition significantly decreased the biomass of Euglypha rotunda, while the biomass of either Centropyxis cassis or Phryganella acropodia was increased by a lower nitrogen addition treatment. This study suggested that the response of peatland testate amoebae to nitrogen addition was species specific, which could potentially be used as an indicator for the environment of peatlands.

The Influence of Leaf Fall and Organic Carbon Availability on Nitrogen Cycling in a Headwater Stream

Science.gov (United States)

Thomas, S. A.; Kristin, A.; Doyle, B.; Goodale, C. L.; Gurwick, N. P.; Lepak, J.; Kulkari, M.; McIntyre, P.; McCalley, C.; Raciti, S.; Simkin, S.; Warren, D.; Weiss, M.

2005-05-01

The study of allochthonous carbon has a long and distinguished history in stream ecology. Despite this legacy, relatively little is known regarding the influence of leaf litter on nutrient dynamics. We conducted 15N-NO3 tracer additions to a headwater stream in upstate New York before and after autumn leaf fall to assess the influence of leaf litter on nitrogen spiraling. In addition, we amended the stream with labile dissolved organic carbon (as acetate) midway through each experiment to examine whether organic carbon availability differentially stimulated nitrogen cycling. Leaf standing stocks increased from 53 to 175 g dry mass m-2 and discharge more than tripled (6 to 20 L s-1) between the pre- and post-leaf fall period. In contrast, nitrate concentration fell from approximately 50 to less then 10 ug L-1. Despite higher discharge, uptake length was shorter following leaf fall under both ambient (250 and 72 m, respectively) and DOC amended (125 and 45 m) conditions. Uptake velocity increased dramatically following leaf fall, despite a slight decline in the areal uptake rate. Dissolved N2 gas samples were also collected to estimate denitrification rates under each experimental condition. The temporal extent of increased nitrogen retention will also be explored.

The soil acidity as restrictive factor of the use of nitrogen fertilizer by spring barley

International Nuclear Information System (INIS)

Hejnak, V.; Lippold, H.

1999-01-01

In two - year micro - plot trials was studied the effect of soil pH value (pH > 6,5 and pH 15 N in first year and no enriched in second year, rates of 0, 85, 170 and 255 mg N per pot, i.e. 0, 30, 60 and 90 kg N.ha -1 ) on the spring barley productivity and on the use of nitrogen fertilizer by plants in the application year of 15 N and in the following year. The productivity of spring barley is significantly higher in neutral soil than in acid soil. The gradated rates of nitrogen fertilization increased this difference. The total nitrogen uptake by plants was higher in neutral soil. The share of the nitrogen from 'the old soil's supply' in the total uptake by the harvest ranges from 95 to 82 % and is practically identical in studied soils. 'Priming effect' was higher in soil with better fertility (153 - 186 mg N per pot) than in acid soil (to 49 mg N per pot only). The gradated rates of ammonium sulphate increased the uptake nitrogen from fertilizer by harvest of spring barley in the application year of 15 N from 39 mg N to 107 mg N per pot in neutral soil and from 26 mg N to 83 mg N per pot in acid soil and in the following year from 3,05 mg N to 8,15 mg N per pot in neutral soil and from 1,76 mg N to 3,37 mg N per pot in acid soil. The total balance of fertilizer nitrogen ( 15 N) in soil - crop system in two years from application showed that in neutral soil 46 % used by spring barley (42 % in the application year and 4 % in the following year), 16 % rested in soil and loss was 38 % and in acid soil 35 % used by harvest (33 % in first year and 2 % second year), 12 % rested in soil and loss was 53 %. Refs. 5 (author)

Importance of soil nitrogen and select intensifying measures in the soil-plant-fertilizer system demonstrated in sugar beets

International Nuclear Information System (INIS)

Rauhe, K.; Sielaff, B.; Barth, F.J.

1981-01-01

Sugar beets were gradually fertilized with 15 N-labelled nitrogen fertilizer without or in combination with irrigation. To gain optimum crop yields 180 - 200 kg/ha fertilizer nitrogen were required. Within the range of maximum yield the total nitrogen uptake amounted to 300 - 360 kg/ha under conditions of irrigation. Nitrogen was taken up from the fertilizer by 40% and from the soil by 60%. The immobilization rate of fertilizer nitrogen was near 30% after 2 years of vegetation. Only 33% and 25%, resp., of soil nitrogen could be replaced by fertilizing without and combined with irrigation, resp. It was shown that despite of increased application of the main intensifying factors, nitrogen and water, the soil nitrogen was mineralized intensively

Studies on the uptake of 14C-neostigmine in the isolated rat diaphragm

International Nuclear Information System (INIS)

Helleberg, L.

1976-01-01

The uptake process of 14 C-neostigmine in striated muscles was studied using the isolated rat diaphragm. Hemidiaphragms were incubated with 3x10 -7 M 14 C-neostigmine at 37deg in Krebs-Ringer solution containing 11 mM glucose and aerated with oxygen:carbon dioxide (95:5 v/v %). The uptake, which is expressed as the muscle-to-medium concentration ratio, was 1.41, after 3 hours, after which the rate of uptake diminished and became equal to that of inulin. The uptake which showed partial saturation, was decreased by some tertiary and quarternary amines, metabolic inhibitors, potassium and in an atmosphere of nitrogen. Neostigmine accumulated in all parts of the muscle without preference for the end plate zone. The half-time for the efflux was about 30 min. The phrenic nerve-diaphragm preparation became desensitized to the effect of 3x10 -7 M neostigmine after 2-3 hours. It is suggested that the uptake of neostigmine is mediated via a specialized carrier transport system. (author)

Genetic Dissection of Root Morphological Traits Related to Nitrogen Use Efficiency in Brassica napus L. under Two Contrasting Nitrogen Conditions

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Jie Wang

2017-09-01

Full Text Available As the major determinant for nutrient uptake, root system architecture (RSA has a massive impact on nitrogen use efficiency (NUE. However, little is known the molecular control of RSA as related to NUE in rapeseed. Here, a rapeseed recombinant inbred line population (BnaZNRIL was used to investigate root morphology (RM, an important component for RSA and NUE-related traits under high-nitrogen (HN and low-nitrogen (LN conditions by hydroponics. Data analysis suggested that RM-related traits, particularly root size had significantly phenotypic correlations with plant dry biomass and N uptake irrespective of N levels, but no or little correlation with N utilization efficiency (NUtE, providing the potential to identify QTLs with pleiotropy or specificity for RM- and NUE-related traits. A total of 129 QTLs (including 23 stable QTLs, which were repeatedly detected at least two environments or different N levels were identified and 83 of them were integrated into 22 pleiotropic QTL clusters. Five RM-NUE, ten RM-specific and three NUE-specific QTL clusters with same directions of additive-effect implied two NUE-improving approaches (RM-based and N utilization-based directly and provided valuable genomic regions for NUE improvement in rapeseed. Importantly, all of four major QTLs and most of stable QTLs (20 out of 23 detected here were related to RM traits under HN and/or LN levels, suggested that regulating RM to improve NUE would be more feasible than regulating N efficiency directly. These results provided the promising genomic regions for marker-assisted selection on RM-based NUE improvement in rapeseed.

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

International Nuclear Information System (INIS)

Abdel Aziz, H.A.

2014-01-01

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

Exploring the nitrogen ingestion of aphids--a new method using electrical penetration graph and (15N labelling.

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Franziska Kuhlmann

Full Text Available Studying plant-aphid interactions is challenging as aphid feeding is a complex process hidden in the plant tissue. Here we propose a combination of two well established methods to study nutrient acquisition by aphids focusing on the uptake of isotopically labelled nitrogen ((15N. We combined the Electrical Penetration Graph (EPG technique that allows detailed recording of aphid feeding behaviour and stable isotope ratio mass spectrometry (IRMS to precisely measure the uptake of nitrogen. Bird cherry-oat aphids Rhopalosiphum padi L. (Hemiptera, Aphididae fed for 24 h on barley plants (Hordeum vulgare L., cultivar Lina, Poaceae that were cultivated with a (15N enriched nutrient solution. The time aphids fed in the phloem was strongly positive correlated with their (15N uptake. All other single behavioural phases were not correlated with (15N enrichment in the aphids, which corroborates their classification as non-feeding EPG phases. In addition, phloem-feeding and (15N enrichment of aphids was divided into two groups. One group spent only short time in the phloem phase and was unsuccessful in nitrogen acquisition, while the other group displayed longer phloem-feeding phases and was successful in nitrogen acquisition. This suggests that several factors such as the right feeding site, time span of feeding and individual conditions play a role for the aphids to acquire nutrients successfully. The power of this combination of methods for studying plant-aphid interactions is discussed.

Understanding plant response to nitrogen limitation for the improvement of crop nitrogen use efficiency.

Science.gov (United States)

Kant, Surya; Bi, Yong-Mei; Rothstein, Steven J

2011-02-01

Development of genetic varieties with improved nitrogen use efficiency (NUE) is essential for sustainable agriculture. Generally, NUE can be divided into two parts. First, assimilation efficiency involves nitrogen (N) uptake and assimilation and second utilization efficiency involves N remobilization. Understanding the mechanisms regulating these processes is crucial for the improvement of NUE in crop plants. One important approach is to develop an understanding of the plant response to different N regimes, especially to N limitation, using various methods including transcription profiling, analysing mutants defective in their normal response to N limitation, and studying plants that show better growth under N-limiting conditions. One can then attempt to improve NUE in crop plants using the knowledge gained from these studies. There are several potential genetic and molecular approaches for the improvement of crop NUE discussed in this review. Increased knowledge of how plants respond to different N levels as well as to other environmental conditions is required to achieve this.

Ammonia Nitrogen Added to Diets Deficient in Dispensable Amino Acid Nitrogen Is Poorly Utilized for Urea Production in Growing Pigs.

Science.gov (United States)

Mansilla, Wilfredo D; Silva, Kayla E; Zhu, Cuilan L; Nyachoti, Charles M; Htoo, John K; Cant, John P; de Lange, Cornelis Fm

2017-12-01

Background: Including ammonia in low-crude protein (CP) diets deficient in dispensable amino acid (DAAs) increases nitrogen retention in growing pigs. Objective: We investigated the absorption and metabolism of dietary ammonia nitrogen in the portal-drained viscera (PDV) and liver of pigs fed a diet deficient in DAA nitrogen. Methods: Eight pigs with an initial mean ± SD body weight (BW) of 26.5 ± 1.4 kg were surgically fitted with 4 catheters each (portal, hepatic and mesenteric veins, and carotid artery). The pigs were fed (2.8 × 191 kcal/kg BW 0.60 ), for 7 d and every 8 h, a diet deficient in DAA nitrogen supplemented with increasing amounts of ammonia nitrogen (CP: 7.76%, 9.27%, and 10.77%; indispensable amino acid nitrogen:total nitrogen ratio: 0.71, 0.59, and 0.50 for control and low- and high-ammonia diets, respectively). The treatment sequence was based on a Latin square design with 3 consecutive periods. On the last day of each period, blood flows in the portal and hepatic veins were determined with a continuous infusion of ρ-amino hippuric acid into the mesenteric vein. Serial blood samples were taken to determine ammonia and urea nitrogen concentration. Net balances of ammonia and urea nitrogen were calculated for the PDV and liver. Results: Cumulative (8 h) ammonia nitrogen appearance in the portal vein increased ( P ≤ 0.05) with ammonia intake (433, 958, and 1629 ± 60 mg ammonia nitrogen/meal for control and low- and high-ammonia diets, respectively). The cumulative hepatic uptake of ammonia nitrogen increased ( P ≤ 0.05) with ammonia nitrogen supply. The cumulative urea nitrogen appearance in the hepatic vein tended to increase ( P ≤ 0.10) only in high-ammonia treatment (-92.5, -59.4, and 209.7 ± 92 mg urea nitrogen/meal for control and low- and high-ammonia diets, respectively) and, relative to the control diet, represented -6.0% and 11% of ammonia nitrogen intake. Conclusion: Dietary ammonia nitrogen is poorly utilized for urea

Nitrogen Fate in a Phreatic Fluviokarst Watershed: a Stable Isotope, Sediment Tracing, and Numerical Modeling Approach

Science.gov (United States)

Husic, A.; Fox, J.; Ford, W. I., III; Agouridis, C.; Currens, J. C.; Taylor, C. J.

2017-12-01

Sediment tracing tools provide an insight into provenance, fate, and transport of sediment and, when coupled to stable isotopes, can elucidate in-stream biogeochemical processes. Particulate nitrogen fate in fluviokarst systems is a relatively unexplored area of research partially due to the complex hydrodynamics at play in karst systems. Karst topography includes turbulent conduits that transport groundwater and contaminants at speeds more typical of open channel flows than laminar Darcian flows. While it is accepted that karst hydro-geomorphology represents a hybrid surface-subsurface system for fluid, further investigation is needed to determine whether, and to what extent, karst systems behave like surface agricultural streams or porous media aquifers with respect to their role in nitrogen cycling. Our objective is to gain an understanding of in-conduit nitrogen processes and their effect on net nitrogen-exports from karst springs to larger waterbodies. The authors apply water, sediment, carbon, and nitrogen tracing techniques to analyze water for nitrate, sediment carbon and nitrogen, and stable sediment nitrogen isotope (δ15N). Thereafter, a new numerical model is formulated that: simulates dissolved inorganic nitrogen and sediment nitrogen transformations in the phreatic karst conduit; couples carbon turnover and nitrogen transformations in the model structure; and simulates the nitrogen stable isotope mass balance for the dissolved and sediment phases. Nitrogen tracing data results show a significant increase in δ15N of sediment nitrogen at the spring outlet relative to karst inputs indicating the potential for isotope fractionation during dissolved N uptake by bed sediments in the conduit and during denitrification within bed sediments. The new numerical modeling structure is then used to reproduce the data results and provide an estimate of the relative dominance of N uptake and denitrification within the surficial sediments of the karst conduit system

Uptake of soil-, foliar-and pod-applied nitrogen and phosphorus by rape (Brassica napus L.)

International Nuclear Information System (INIS)

Zhang Qinzheng; Xi Haifu; Lang Xianhua

1992-01-01

Uptake of soil-applied and foliar-and pod applied N, P by rape was studied by using 32 P and 15 N labelled fertilizer under pot culture condition. Application of phosphorus fertilizer to purplish clayey paddy soil which was poor in available P had influence on utilization of basal-dressed NH 4 HCO 3 by rape and subsequently on its growth and seed yield. Utilization rate of applied N in whole plant and seeds were 3.66 and 5.13 fold respectively as compared with control when 187.5 kg/ha of superphosphate were applied and increased with increasing application of superphosphate (187.5-562.5 kg/ha). Application of P fertilizer not only increased uptake of N but also promoted transportation of N from vegetative organs to seeds. Rape plant uptook 69.09% of foliar-and pod-applied N in form of 2% solution of urea after flowering and transported the N to seeds in greater proportion than that of soil-applied N. In the same period, 60% of foliar- and pod-applied P in form of 0.2% KH 2 PO 4 was absorbed by rape plant, most of which was in leaves. Uptake of N and P by rape increased 17.89% and 27.78% respectively when urea and phosphate was applied together compared with using urea and phosphate alone. Uptake of basal-dressed P by rape plant was 6% at early growing stage

Terrestrial nitrogen-carbon cycle interactions at the global scale.

Science.gov (United States)

Zaehle, S

2013-07-05

Interactions between the terrestrial nitrogen (N) and carbon (C) cycles shape the response of ecosystems to global change. However, the global distribution of nitrogen availability and its importance in global biogeochemistry and biogeochemical interactions with the climate system remain uncertain. Based on projections of a terrestrial biosphere model scaling ecological understanding of nitrogen-carbon cycle interactions to global scales, anthropogenic nitrogen additions since 1860 are estimated to have enriched the terrestrial biosphere by 1.3 Pg N, supporting the sequestration of 11.2 Pg C. Over the same time period, CO2 fertilization has increased terrestrial carbon storage by 134.0 Pg C, increasing the terrestrial nitrogen stock by 1.2 Pg N. In 2001-2010, terrestrial ecosystems sequestered an estimated total of 27 Tg N yr(-1) (1.9 Pg C yr(-1)), of which 10 Tg N yr(-1) (0.2 Pg C yr(-1)) are due to anthropogenic nitrogen deposition. Nitrogen availability already limits terrestrial carbon sequestration in the boreal and temperate zone, and will constrain future carbon sequestration in response to CO2 fertilization (regionally by up to 70% compared with an estimate without considering nitrogen-carbon interactions). This reduced terrestrial carbon uptake will probably dominate the role of the terrestrial nitrogen cycle in the climate system, as it accelerates the accumulation of anthropogenic CO2 in the atmosphere. However, increases of N2O emissions owing to anthropogenic nitrogen and climate change (at a rate of approx. 0.5 Tg N yr(-1) per 1°C degree climate warming) will add an important long-term climate forcing.

Nitrogen retention in river corridors: European perspective

Energy Technology Data Exchange (ETDEWEB)

Haycock, N [Dept. of Agriculture and Water Management, Silsoe College, Cranfield Institute of Technology (United Kingdom); Pinay, G [CERR/CNRS, Toulouse (France); Walker, Charles [SBEG, Inst. of Ecology, Lund Univ. (Sweden)

1993-01-01

The problem of nitrogen pollution in European surface- and groundwaters has become a focus of recent European and Scandinavian directives, with legislation calling for a 50% reduction of N losses by the years 1995 and 2000, respectively. This paper provides a conceptual framework upon which management strategies to reduce losses of diffuse nitrogen pollution to surface waters may be based. The control of nitrogen pollution may take place through an increase in the complexity of the landscape, not throughout the catchment area, but rather in specific zones, the river corridor in particular. Within river corridors, riparian areas have been recognized globally for their value as nutrient removal ''buffer systems''. Studies have identified vegetation uptake and microbial denitrification as the primary mechanisms responsible for N removal in these systems. For these processes to function optimally on an annual basis, both vegetation and water regime must be managed. The establishment and management of riparian buffer zones in suitable places within river corridors, will provide a stable and sustainable water-protection function. This will complement future nitrogen input control strategies, needed for both the long-term protection of groundwater and surface waters in Europe as a whole, and for the proposed 50% reduction in nitrogen loading to the Baltic and North Sea coastal waters by the turn of the century. 52 refs, 5 figs

Seasonal variability in nitrate and phosphate uptake kinetics in a forested headwater stream using pulse nutrient additions

Science.gov (United States)

Griffiths, N. A.; Mulholland, P. J.

2011-12-01

We used the Tracer Additions for Spiraling Curve Characterization (TASCC) approach to quantify seasonal variability in ambient nutrient spiraling metrics and nutrient uptake kinetics in the West Fork of Walker Branch, a forested headwater stream in eastern Tennessee, USA. We performed instantaneous additions of nitrate (NO3-) and phosphate (PO4-3) separately with a conservative tracer (chloride, Cl-) during the following biologically-important time periods: autumn (during leaf fall, high organic matter [OM] standing stocks), winter (low OM standing stocks), spring (prior to canopy closure), and summer (closed canopy). We predicted that nutrient demand would be highest during autumn and spring, as OM inputs fuel heterotrophic respiration and high light availability stimulates autotrophic production, respectively. The measured ambient PO4-3 uptake rates (Vf-amb) followed our predictions, with the highest Vf-amb rates in autumn (Vf-amb = 2.8 mm/min) and spring (Vf-amb = 2.9 mm/min), and undetectable uptake in winter. Further, maximum areal PO4-3 uptake rates (Umax) were higher in autumn (Umax = 297 μg/m2/min) than spring (Umax = 106 μg/m2/min), possibly due to greater nutrient demand of heterotrophs on leaf litter accumulations. Contrary to our predictions, ambient NO3- uptake rates were highest in autumn and winter (autumn: Vf-amb = 2.8 mm/min, winter: Vf-amb = 2.4 mm/min), and lowest in spring (Vf-amb = 1.0 mm/min). The higher than expected Vf-amb rate in winter may be due to higher stream metabolism rates and thus greater nitrogen demand; the lower than expected Vf-amb rate in spring may reflect an alleviation of nitrogen demand due to high ammonium concentrations during this time. As the demand for both nitrogen and phosphorus in Walker Branch is greatest in autumn, future work will characterize how nutrient metrics change during this dynamic time period (i.e., before, during, and after leaf fall).

Competition for nitrogen between Fagus sylvatica and Acer pseudoplatanus seedlings depends on soil nitrogen availability

Directory of Open Access Journals (Sweden)

Xiuyuan eLi

2015-04-01

Full Text Available Competition for nitrogen (N, particularly in resource-limited habitats, might be avoided by different N acquisition strategies of plants. In our study, we investigated whether slow-growing European beech and fast-growing sycamore maple seedlings avoid competition for growth-limiting N by different N uptake patterns and the potential alteration by soil N availability in a microcosm experiment. We quantified growth and biomass indices, 15N uptake capacity and N pools in the fine roots. Overall, growth indices, N acquisition and N pools in the fine roots were influenced by species-specific competition depending on soil N availability. With interspecific competition, growth of sycamore maple reduced regardless of soil N supply, whereas beech only showed reduced growth when N was limited. Both species responded to interspecific competition by alteration of N pools in the fine roots; however, sycamore maple showed a stronger response compared to beech for almost all N pools in roots, except for structural N at low soil N availability. Beech generally preferred organic N acquisition while sycamore maple took up more inorganic N. Furthermore, with interspecific competition, beech had an enhanced organic N uptake capacity, while in sycamore maple inorganic N uptake capacity was impaired by the presence of beech. Although sycamore maple could tolerate the suboptimal conditions at the cost of reduced growth, our study indicates its reduced competitive ability for N compared to beech.

Improving efficiencies of irrigation and nitrogen uptake in wheat

International Nuclear Information System (INIS)

Bazza, M.

2000-01-01

Three years of field studies and lysimeter experiments on irrigated wheat had the objective of finding ways of managing irrigation and N fertilization to minimize losses and reduce contamination of groundwater. Applied N had significant positive effects on crop-water consumptive use. The highest N losses occurred during early growth. Irrigation had little effect on N loss when it was practiced efficiently. Under the prevailing conditions, it is recommended that no N be applied to wheat at planting, in order to limit N losses by leaching caused by the high precipitation that usually occurs during early development when crop-N requirements are small. No more than 120 kg N ha -1 should be applied in total to minimize groundwater pollution and maximize N-uptake efficiency and economic returns. Also, for economic and environmental reasons, irrigation should be limited to 80% of the total requirement and to depths of 40 to 60 mm. (author)

In-Situ Air Sparaing: Engineering and Design

Science.gov (United States)

2008-01-31

removal (Adams and Reddy 2000). The potential for remediation of less volatile LNAPLs (e.g., diesel or fuel oils) is less promising, relying more on...pure nitrogen, or nitrous oxide) may enhance the speed at which bioremediation proceeds or alter the conditions under which it occurs. The USDOE Sa...region below the water table is directly related to in- situ bioremediation . IAS can be an alternative to other means of introducing oxygen into the

Effects of Mg on C and N Metabolism of Soybean at Different Nitrogen Supplying Levels

Institute of Scientific and Technical Information of China (English)

LANG Man; LIU Yuanying; PENG Xianlong; ZHANG Wenzhao

2006-01-01

A pot experiment was conducted to study the effects of magnesium on carbon and nitrogen metabolism of soybean at different nitrogen supplying levels. The results showed that the effects of magnesium at low nitrogen rate on N content, soluble protein, soluble sugar contents were not alike at different growth stage, although nodule dry weights raised, the yield and protein content of seeds decreased, however, the oil content was improved.The application of magnesium at medium and high nitrogen supplying levels promoted the uptake of N effectively,increased the soluble protein and soluble sugar contents, but the nodule dry weights of application magnesium at medium nitrogen supplying level decreased and the yield increased only a little despite the improved quality.Application of magnesium at high nitrogen supplying level raised nodule dry weights and soybean yield significantly, the quality of seeds was also improved.

QTL and QTL x environment effects on agronomic and nitrogen acquisition traits in rice.

Science.gov (United States)

Senthilvel, Senapathy; Vinod, Kunnummal Kurungara; Malarvizhi, Palaniappan; Maheswaran, Marappa

2008-09-01

Agricultural environments deteriorate due to excess nitrogen application. Breeding for low nitrogen responsive genotypes can reduce soil nitrogen input. Rice genotypes respond variably to soil available nitrogen. The present study attempted quantification of genotype x nitrogen level interaction and mapping of quantitative trait loci (QTLs) associated with nitrogen use efficiency (NUE) and other associated agronomic traits. Twelve parameters were observed across a set of 82 double haploid (DH) lines derived from IR64/Azucena. Three nitrogen regimes namely, native (0 kg/ha; no nitrogen applied), optimum (100 kg/ha) and high (200 kg/ha) replicated thrice were the environments. The parents and DH lines were significantly varying for all traits under different nitrogen regimes. All traits except plant height recorded significant genotype x environment interaction. Individual plant yield was positively correlated with nitrogen use efficiency and nitrogen uptake. Sixteen QTLs were detected by composite interval mapping. Eleven QTLs showed significant QTL x environment interactions. On chromosome 3, seven QTLs were detected associated with nitrogen use, plant yield and associated traits. A QTL region between markers RZ678, RZ574 and RZ284 was associated with nitrogen use and yield. This chromosomal region was enriched with expressed gene sequences of known key nitrogen assimilation genes.

Plants' use of different nitrogen forms in response to crude oil contamination

International Nuclear Information System (INIS)

Nie Ming; Lu Meng; Yang Qiang; Zhang Xiaodong; Xiao Ming; Jiang Lifen; Yang Ji; Fang Changming; Chen Jiakuan; Li Bo

2011-01-01

In this study, we investigated Phragmites australis' use of different forms of nitrogen (N) and associated soil N transformations in response to petroleum contamination. 15 N tracer studies indicated that the total amount of inorganic and organic N assimilated by P. australis was low in petroleum-contaminated soil, while the rates of inorganic and organic N uptake on a per-unit-biomass basis were higher in petroleum-contaminated soil than those in un-contaminated soil. The percentage of organic N in total plant-assimilated N increased with petroleum concentration. In addition, high gross N immobilization and nitrification rates relative to gross N mineralization rate might reduce inorganic-N availability to the plants. Therefore, the enhanced rate of N uptake and increased importance of organic N in plant N assimilation might be of great significance to plants growing in petroleum-contaminated soils. Our results suggest that plants might regulate N capture under petroleum contamination. - Plant strategies of utilizing nitrogen in crude oil-contaminated soils.

A Biogeochemical Oceanographer at Sea: My Life with Nitrogen and a Nod to Silica

Science.gov (United States)

Dugdale, Richard C.

2018-01-01

My evolution from electrical engineering student to limnologist and then to oceanographer was a consequence of generous mentoring, which led to my use of the 15N tracer technique to measure nitrogen fixation in aquatic systems. The concept of new and regenerated production arose when I applied this method to measure nitrate and ammonium uptake in marine ecosystems. I then showed that enzyme kinetics could be applied to algal nitrogen uptake and used a silicate pump to explain silicate limitation of diatoms in coastal and equatorial upwelling systems. These concepts are now recognized as modern nutrient paradigms in biogeochemical oceanography. My interest in nutrients required field studies and led to my passion for the study of upwelling ecosystems and the establishment of two major international programs, with numerous advisors, collaborators, and students helping along the way.

Nitrogen Dynamic Study on Rice Mutant Lines Using 15N Isotope Techniques

International Nuclear Information System (INIS)

Ahmad Nazrul Abd Wahid; Shyful Azizi Abdul Rahman; Abdul Rahim Harun

2015-01-01

Malaysian Nuclear Agency in collaboration with UPM and MARDI has produced two types of rice mutant lines of MR219, viz. MR219-4 and MR219-9 developed under rice radiation mutagenenesis programme for adaptability to aerobic conditions. Aerobic cultivating is rice cultivation system on well drained soil and using minimal water input. At Malaysian Nuclear Agency, a nitrogen fertilization study in aerobic condition for the rice mutant lines was carried out in the shade house and field. The study is intended to examine and assess the dynamics of nitrogen by rice mutant lines through the different soil water management and nitrogen levels. Direct 15 N isotopic tracer method was used in this study, whereby the 15 N labeled urea fertilizer was utilized as a tracer for nitrogen nutrient uptake by the test crops. This paper is intended to highlight the progress that has been made in the study of the nitrogen dynamics on MR219-4 and MR219-9 rice mutant lines. (author)

Spectral measurements at different spatial scales in potato: relating leaf, plant and canopy nitrogen status

Science.gov (United States)

Jongschaap, Raymond E. E.; Booij, Remmie

2004-09-01

Chlorophyll contents in vegetation depend on soil nitrogen availability and on crop nitrogen uptake, which are important management factors in arable farming. Crop nitrogen uptake is important, as nitrogen is needed for chlorophyll formation, which is important for photosynthesis, i.e. the conversion of absorbed radiance into plant biomass. The objective of this study was to estimate leaf and canopy nitrogen contents by near and remote sensing observations and to link observations at leaf, plant and canopy level. A theoretical base is presented for scaling-up leaf optical properties to whole plants and crops, by linking different optical recording techniques at leaf, plant and canopy levels through the integration of vertical nitrogen distribution. Field data come from potato experiments in The Netherlands in 1997 and 1998, comprising two potato varieties: Eersteling and Bintje, receiving similar nitrogen treatments (0, 100, 200 and 300 kg N ha -1) in varying application schemes to create differences in canopy nitrogen status during the growing season. Ten standard destructive field samplings were performed to follow leaf area index and crop dry weight evolution. Samples were analysed for inorganic nitrogen and total nitrogen contents. At sampling dates, spectral measurements were taken both at leaf level and at canopy level. At leaf level, an exponential relation between SPAD-502 readings and leaf organic nitrogen contents with a high correlation factor of 0.91 was found. At canopy level, an exponential relation between canopy organic nitrogen contents and red edge position ( λrep, nm) derived from reflectance measurements was found with a good correlation of 0.82. Spectral measurements (SPAD-502) at leaf level of a few square mm were related to canopy reflectance measurements (CropScan™) of approximately 0.44 m 2. Statistical regression techniques were used to optimise theoretical vertical nitrogen profiles that allowed scaling-up leaf chlorophyll measurements

Agronomic performance and chemical response of sunflower ( Helianthus annuus L.) to some organic nitrogen sources and conventional nitrogen fertilizers under sandy soil conditions

Energy Technology Data Exchange (ETDEWEB)

Helmy, A. M.; Fawzy Ramadan, M. F.

2009-07-01

Sunflower ( Helianthus annuus L.) is an option for oilseed production, particularly in dry land areas due to good root system development. In this study, two field experiments were performed in the El-Khattara region (Sharkia Governorate, Egypt) during the 2005 season. The objective of this research was to determine the effect of organic nitrogen (ON) sources and their combinations as well as to compare the effect of ON and ammonium sulfate (AS) as a conventional fertilizer added individually or in combination on growth, yield components, oil percentage and the uptake of some macro nutrients by sunflowers grown on sandy soil.The treatments of chicken manure (CM) and a mixture of farmyard manure (FYM) with CM were superior to the other treatments and gave the highest yield, dry matter yield, NPK uptake by plants at all growth stages along with seed yield at the mature stage. The effect of the different ON on crop yield and its components may follow the order; CM> palma residues (PR)> FYM. This was more emphasized when the materials were mixed with AS at a ratio of 3:1 and 1:1. The uptake of nitrogen (N), phosphorus (P) and potassium (K) by plants was affected by the addition of different N sources and treatments. The highest nutrient content and uptake by straw were obtained when treated with CM followed by PR at all growth stages, while it was PR followed by CM for seeds. Oil recovery was shown to respond to the N supply and the changes in individual fatty acids were not statistically different. However, it seems that the application of organic fertilizers resulted in an increase in total unsaturated fatty acids compared to the control. (Author) 58 refs.

Nitrogen fate model for gas-phase ammonia-enhanced in situ bioventing

International Nuclear Information System (INIS)

Marshall, T.R.

1995-01-01

Subsurface bioremediation of contaminants is sometimes limited by the availability of nitrogen. Introduction of gaseous ammonia to the subsurface is a feasible and economical approach to enhance biodegradation in some environments. A gaseous nutrient source may be a practical option for sites where surface application of liquid nutrients is not possible, such as sites with shallow groundwater or sites with surface operations. A conceptual nitrogen fate model was developed to provide remediation scientists and engineers with some practical guidelines in the use of ammonia-enhanced bioventing. Ammonia supplied to the subsurface dissolves readily in soil moisture and sorbs strongly to soil particles. The ammonium ion is the preferred nutrient form of many microorganisms. Some of the ammonia will be converted to nitrate by ammonia-oxidizing organisms. Field monitoring data from an operating ammonia-enhanced bioventing remediation site for diesel fuel contamination are presented. Conservative additions of ammonia promoted appreciable increases in evolved carbon dioxide and rate of oxygen utilization. An overabundance of added ammonia promoted formation of methane from likely anaerobic hydrocarbon degradation in the presence of nitrate as the electron acceptor

Whole-ecosystem nitrogen effects research in Europe

International Nuclear Information System (INIS)

Sullivan, T.J.

1993-01-01

There has been an enormous increase during the past few years in the amount of research being conducted in Europe on the effects of atmospheric deposition of nitrogen on aquatic, and especially terrestrial, ecosystems. Nitrogen deposition increases the emissions of N 2 O from forest soils and may decrease CH 4 uptake. Both increased N 2 O production and decreased CH 4 consumption would increase the concentration of greenhouse gases in the atmosphere. Thus there are important linkages between nitrogen deposition (and consequent ecosystem effects) and the release of greenhouse gases that have been implicated in potential global climate change. This paper summarises some of the European research that has been carried out in recent years. The experimental approach has shifted heavily into whole-ecosystem experimental manipulations, which are being conducted across gradients of atmospheric deposition and other environmental factors. Manipulations are focused primarily on coniferous forest ecosystems and involve increasing ambient deposition of sulfur and nitrogen; excluding ambient deposition via the construction of roofs over entire forested plots or catchments; and manipulating climatic factors, especially water availability. Experiments are designed to continue for long periods (i.e., 5-10 years) and are augmented by detailed, process-level studies at the manipulation sites. Results of the broad-scale and detailed studies are being used to build, test, and validate mathematical models that simulate nitrogen processing, nutrient cycling, and water regulation in coniferous forest ecosystems under varying depositional and climatic regimes. Ultimately, these models will be used to predict nitrogen saturation, estimate the critical loads of nitrogen for European forests, and specify emission controls needed to protect European forests and surface waters from the detrimental effects of excess nitrogen deposition. 19 refs., 1 fig., 2 photos

In situ phosphorus-doped polysilicon for excitation and detection in micromechanical resonators

NARCIS (Netherlands)

Bouwstra, S.; Bouwstra, Siebe; de Weerd, Eddy L; Elwenspoek, Michael Curt

Low-pressure chemical vapour deposited (LPCVD) in situ phosphorus-doped polysilicon films have been grown from a 60:30:300 sccm silane:phosphine (2000 ppm):nitrogen mass-flow mixture at 625°C under varied process conditions. Thickness uniformity, grain size, dopant concentration, resistivity,

Sphagnum mosses--masters of efficient N-uptake while avoiding intoxication.

Science.gov (United States)

Fritz, Christian; Lamers, Leon P M; Riaz, Muhammad; van den Berg, Leon J L; Elzenga, Theo J T M

2014-01-01

Peat forming Sphagnum mosses are able to prevent the dominance of vascular plants under ombrotrophic conditions by efficiently scavenging atmospherically deposited nitrogen (N). N-uptake kinetics of these mosses are therefore expected to play a key role in differential N availability, plant competition, and carbon sequestration in Sphagnum peatlands. The interacting effects of rain N concentration and exposure time on moss N-uptake rates are, however, poorly understood. We investigated the effects of N-concentration (1, 5, 10, 50, 100, 500 µM), N-form ((15)N-ammonium or nitrate) and exposure time (0.5, 2, 72 h) on uptake kinetics for Sphagnum magellanicum from a pristine bog in Patagonia (Argentina) and from a Dutch bog exposed to decades of N-pollution. Uptake rates for ammonium were higher than for nitrate, and N-binding at adsorption sites was negligible. During the first 0.5 h, N-uptake followed saturation kinetics revealing a high affinity (Km 3.5-6.5 µM). Ammonium was taken up 8 times faster than nitrate, whereas over 72 hours this was only 2 times. Uptake rates decreased drastically with increasing exposure times, which implies that many short-term N-uptake experiments in literature may well have overestimated long-term uptake rates and ecosystem retention. Sphagnum from the polluted site (i.e. long-term N exposure) showed lower uptake rates than mosses from the pristine site, indicating an adaptive response. Sphagnum therefore appears to be highly efficient in using short N pulses (e.g. rainfall in pristine areas). This strategy has important ecological and evolutionary implications: at high N input rates, the risk of N-toxicity seems to be reduced by lower uptake rates of Sphagnum, at the expense of its long-term filter capacity and related competitive advantage over vascular plants. As shown by our conceptual model, interacting effects of N-deposition and climate change (changes in rainfall) will seriously alter the functioning of Sphagnum peatlands.

Sphagnum Mosses - Masters of Efficient N-Uptake while Avoiding Intoxication

Science.gov (United States)

Fritz, Christian; Lamers, Leon P. M.; Riaz, Muhammad; van den Berg, Leon J. L.; Elzenga, Theo J. T. M.

2014-01-01

Peat forming Sphagnum mosses are able to prevent the dominance of vascular plants under ombrotrophic conditions by efficiently scavenging atmospherically deposited nitrogen (N). N-uptake kinetics of these mosses are therefore expected to play a key role in differential N availability, plant competition, and carbon sequestration in Sphagnum peatlands. The interacting effects of rain N concentration and exposure time on moss N-uptake rates are, however, poorly understood. We investigated the effects of N-concentration (1, 5, 10, 50, 100, 500 µM), N-form (15N - ammonium or nitrate) and exposure time (0.5, 2, 72 h) on uptake kinetics for Sphagnum magellanicum from a pristine bog in Patagonia (Argentina) and from a Dutch bog exposed to decades of N-pollution. Uptake rates for ammonium were higher than for nitrate, and N-binding at adsorption sites was negligible. During the first 0.5 h, N-uptake followed saturation kinetics revealing a high affinity (Km 3.5–6.5 µM). Ammonium was taken up 8 times faster than nitrate, whereas over 72 hours this was only 2 times. Uptake rates decreased drastically with increasing exposure times, which implies that many short-term N-uptake experiments in literature may well have overestimated long-term uptake rates and ecosystem retention. Sphagnum from the polluted site (i.e. long-term N exposure) showed lower uptake rates than mosses from the pristine site, indicating an adaptive response. Sphagnum therefore appears to be highly efficient in using short N pulses (e.g. rainfall in pristine areas). This strategy has important ecological and evolutionary implications: at high N input rates, the risk of N-toxicity seems to be reduced by lower uptake rates of Sphagnum, at the expense of its long-term filter capacity and related competitive advantage over vascular plants. As shown by our conceptual model, interacting effects of N-deposition and climate change (changes in rainfall) will seriously alter the functioning of Sphagnum peatlands

Use of a dynamic simulation model to understand nitrogen cycling in the middle Rio Grande, NM.

Energy Technology Data Exchange (ETDEWEB)

Meixner, Tom (University of Arizona, Tucson, AZ); Tidwell, Vincent Carroll; Oelsner, Gretchen (University of Arizona, Tucson, AZ); Brooks, Paul (University of Arizona, Tucson, AZ); Roach, Jesse D.

2008-08-01

Water quality often limits the potential uses of scarce water resources in semiarid and arid regions. To best manage water quality one must understand the sources and sinks of both solutes and water to the river system. Nutrient concentration patterns can identify source and sink locations, but cannot always determine biotic processes that affect nutrient concentrations. Modeling tools can provide insight into these large-scale processes. To address questions about large-scale nitrogen removal in the Middle Rio Grande, NM, we created a system dynamics nitrate model using an existing integrated surface water--groundwater model of the region to evaluate our conceptual models of uptake and denitrification as potential nitrate removal mechanisms. We modeled denitrification in groundwater as a first-order process dependent only on concentration and used a 5% denitrification rate. Uptake was assumed to be proportional to transpiration and was modeled as a percentage of the evapotranspiration calculated within the model multiplied by the nitrate concentration in the water being transpired. We modeled riparian uptake as 90% and agricultural uptake as 50% of the respective evapotranspiration rates. Using these removal rates, our model results suggest that riparian uptake, agricultural uptake and denitrification in groundwater are all needed to produce the observed nitrate concentrations in the groundwater, conveyance channels, and river as well as the seasonal concentration patterns. The model results indicate that a total of 497 metric tons of nitrate-N are removed from the Middle Rio Grande annually. Where river nitrate concentrations are low and there are no large nitrate sources, nitrate behaves nearly conservatively and riparian and agricultural uptake are the most important removal mechanisms. Downstream of a large wastewater nitrate source, denitrification and agricultural uptake were responsible for approximately 90% of the nitrogen removal.

Modeling phytoremediation of nitrogen-polluted water using water hyacinth (Eichhornia crassipes)

Science.gov (United States)

Mayo, Aloyce W.; Hanai, Emmanuel E.

2017-08-01

Water hyacinth (Eichhornia crassipes) has a great potential for purification of wastewater through physical, chemical and biological mechanisms. In an attempt to improve the quality of effluents discharged from waste stabilization ponds at the University of Dar es Salaam, a pilot plant was constructed to experiment the effectiveness of this plants for transformation and removal of nitrogen. Samples of wastewater were collected and examined for water quality parameters, including pH, temperature, dissolved oxygen, and various forms of nitrogen, which were used as input parameters in a kinetic mathematical model. A conceptual model was then developed to model various processes in the system using STELLA 6.0.1 software. The results show that total nitrogen was removed by 63.9%. Denitrification contributed 73.8% of the removed nitrogen. Other dominant nitrogen removal mechanisms are net sedimentation and uptake by water hyacinth, which contributed 16.7% and 9.5% of the removed nitrogen, respectively. The model indicated that in presence of water hyacinth biofilm about 1.26 g Nm-2day-1 of nitrogen was removed. However, in the absence of biofilm in water hyacinth pond, the permanent nitrogen removal was only 0.89 g Nm-2day-1. This suggests that in absence of water hyacinth, the efficiency of nitrogen removal would decrease by 29.4%.

Some observation on the root growth of young apple trees and their uptake of nutrients when grown in herbicided strips in grassed orchards

International Nuclear Information System (INIS)

Atkinson, D.

1977-01-01

Root laboratory observations of the root growth of 4-year-old trees of Cox/M.26 planted in a herbicided strip in grass indicated that during the year 70% of the new growth occurred in the strip. Growth appeared to begin earlier during the year under bare soil than under grass. Nitrogen absorption from the strip and the grassed alley was assessed by measuring 15 N uptake; at 10 cm depth uptake was almost entirely from the strip. An experiment using 2-year-old trees of Cox/M.106 and 15 N placements at 7.5 and 15 cm depths in the strip and 15 cm in the grassed alley gave similar results. With 32 P as a tracer and similar trees a small amount of uptake from 25 cm depth under grass was detected. The experiments indicate that young trees produce most of their new roots in the herbicide strips where most of their nutrient uptake occurs and little or none from the grassed alleys. The absorption of nitrogen into the leaves was greater in early summer than autumn

Sediment pollution characteristics and in situ control in a deep drinking water reservoir.

Science.gov (United States)

Zhou, Zizhen; Huang, Tinglin; Li, Yang; Ma, Weixing; Zhou, Shilei; Long, Shenghai

2017-02-01

Sediment pollution characteristics, in situ sediment release potential, and in situ inhibition of sediment release were investigated in a drinking water reservoir. Results showed that organic carbon (OC), total nitrogen (TN), and total phosphorus (TP) in sediments increased from the reservoir mouth to the main reservoir. Fraction analysis indicated that nitrogen in ion exchangeable form and NaOH-extractable P (Fe/Al-P) accounted for 43% and 26% of TN and TP in sediments of the main reservoir. The Risk Assessment Code for metal elements showed that Fe and Mn posed high to very high risk. The results of the in situ reactor experiment in the main reservoir showed the same trends as those observed in the natural state of the reservoir in 2011 and 2012; the maximum concentrations of total OC, TN, TP, Fe, and Mn reached 4.42mg/L, 3.33mg/L, 0.22mg/L, 2.56mg/L, and 0.61mg/L, respectively. An in situ sediment release inhibition technology, the water-lifting aerator, was utilized in the reservoir. The results of operating the water-lifting aerator indicated that sediment release was successfully inhibited and that OC, TN, TP, Fe, and Mn in surface sediment could be reduced by 13.25%, 15.23%, 14.10%, 5.32%, and 3.94%, respectively. Copyright © 2016. Published by Elsevier B.V.

Nitrogen cycling in a turbid, tidal estuary - de stikstofkringloop in een troebel getijden estuarium

NARCIS (Netherlands)

Andersson, M.G.I.

2007-01-01

In this thesis I investigated nitrification, dissolved inorganic and organic nitrogen uptake, and the relative importance of nitrification and ammonium assimilation. I have also investigated exchange with marshes and sediments. Nitrification, oxidation of ammonium to nitrate is the first step for

In situ measurement of some soil properties in paddy soil using visible and near-infrared spectroscopy.

Directory of Open Access Journals (Sweden)

Ji Wenjun

Full Text Available In situ measurements with visible and near-infrared spectroscopy (vis-NIR provide an efficient way for acquiring soil information of paddy soils in the short time gap between the harvest and following rotation. The aim of this study was to evaluate its feasibility to predict a series of soil properties including organic matter (OM, organic carbon (OC, total nitrogen (TN, available nitrogen (AN, available phosphorus (AP, available potassium (AK and pH of paddy soils in Zhejiang province, China. Firstly, the linear partial least squares regression (PLSR was performed on the in situ spectra and the predictions were compared to those with laboratory-based recorded spectra. Then, the non-linear least-square support vector machine (LS-SVM algorithm was carried out aiming to extract more useful information from the in situ spectra and improve predictions. Results show that in terms of OC, OM, TN, AN and pH, (i the predictions were worse using in situ spectra compared to laboratory-based spectra with PLSR algorithm (ii the prediction accuracy using LS-SVM (R2>0.75, RPD>1.90 was obviously improved with in situ vis-NIR spectra compared to PLSR algorithm, and comparable or even better than results generated using laboratory-based spectra with PLSR; (iii in terms of AP and AK, poor predictions were obtained with in situ spectra (R2<0.5, RPD<1.50 either using PLSR or LS-SVM. The results highlight the use of LS-SVM for in situ vis-NIR spectroscopic estimation of soil properties of paddy soils.

Comparison of the uptake and assimilation of ammonium and nitrate in Indica and Japonica rice plants using the tracer 15N method

International Nuclear Information System (INIS)

Ta, T.C.; Ohira, Koji

1982-01-01

The uptake of 15 N-labeled ammonium and nitrate and their assimilation in 4-week-old Indica and Japonica rice plants were studied during 24 hr exposure to 2 mM solutions of ( 15 NH 4 ) 2 SO 4 and/or Na 15 NO 3 . Although there was no clear difference in the uptake and assimilation of 15 NH 4+ , significant differences in the uptake and assimilation of 15 NO 3- by both varieties were observed. When NH 4+ or NO 3- was supplied exclusively, the Indica rice plants absorbed the latter more effectively than the Japonica. In addition, despite a preference for uptake of NH 4+ rather than NO 3- as shown by both varieties when both forms were supplied together, the relative amounts of NO 3- uptake by the Indica were higher than those of Japonica. On the other hand, the Indica rice plants reduced the absorbed 15 NO 3- more rapidly than the Japonica. The incorporation 15 NO 3- into the ethanol insoluble nitrogen fraction of the Indica rice also exceeded that of the Japonica. These results suggest that the Indica has the ability to utilize NO 3- as a nitrogen source more effectively than the Japonica rice plants. (author)

Relationship between sodium influx and salt tolerance of nitrogen-fixing cyanobacteria

Energy Technology Data Exchange (ETDEWEB)

Apte, S.K.; Reddy, B.R.; Thomas, J.

1987-08-01

The relationship between sodium uptake and cyanobacterial salt (NaCl) tolerance has been examined in two filamentous, heterocystous, nitrogen-fixing species of Anabaena. During diazotrophic growth at neutral pH of the growth medium, Anabaena sp. strain L-31, a freshwater strain, showed threefold higher uptake of Na+ than Anabaena torulosa, a brackish-water strain, and was considerably less salt tolerant (50% lethal dose of NaCl, 55 mM) than the latter (50% lethal dose of NaCl, 170 mM). Alkaline pH or excess K+ (more than 25 mM) in the medium causes membrane depolarization and inhibits Na+ influx in both cyanobacteria (S.K. Apte and J. Thomas, Eur. J. Biochem. 154:395-401, 1986). The presence of nitrate or ammonium in the medium caused inhibition of Na+ influx accompanied by membrane depolarization. These experimental manipulations affecting Na+ uptake demonstrated a good negative correlation between Na+ influx and salt tolerance. All treatments which inhibited Na+ influx (such as alkaline pH, K+ above 25 mM, NO3-, and NH4+), enhanced salt tolerance of not only the brackish-water but also the freshwater cyanobacterium. The results indicate that curtailment of Na+ influx, whether inherent or effected by certain environmental factors (e.g., combined nitrogen, alkaline pH), is a major mechanism of salt tolerance in cyanobacteria. (Refs. 27)

Development of nitrogen supply strategy for Scenedesmus rubescens attached cultivation toward growth and lipid accumulation.

Science.gov (United States)

Cheng, Pengfei; Wang, Yan; Osei-Wusu, David; Wang, Yuanzhu; Liu, Tianzhong

2018-03-01

In this study, the microalgae Scenedesmus rubescens were cultivated under the following nitrogen sources, nitrogen concentrations, and nitrogen feeding times (NFTs). This was to help assess biomass and lipid productivity. Scenedesmus rubescens can grow well by adhering to the cellulose acetate membrane in five kinds of nitrogen medium: KNO 3 , urea, NaNO 3 , (NH 4 ) 2 CO 3 , and NH 4 NO 3 . Under the criteria of bio-productivity and lipid productivity, urea was the optimal nitrogen source. Among different urea concentrates, biomass productivity and lipid content of S. rubescens cultivated in 0.27 g/L urea medium were optimized at 8.8 g/(m 2  day) and 31.1%, respectively. With attached cultivation, the highest biomass of 9.4 g/m 2 was obtained at NFTs of 4 days. These results showed that culturing S. rubescens using urea as sole nitrogen source by improving nitrogen uptake with attached cultivation is more efficient.

Potential NH{sub 4}{sup +} and NO{sub 3}{sup -} uptake on various Sphagnum species

Energy Technology Data Exchange (ETDEWEB)

Jauhiainen, J [Joensuu Univ. (Finland). Dept. of Biology; Wallen, B; Malmer, N [Lund Univ. (Sweden). Dept. of Plant Ecology

1997-12-31

The objective of this research is to test differences in NH{sub 4}{sup +} and NO{sub 3}{sup -} uptake on various Sphagnum species under laboratory conditions. The studied species represent two gradients: the minerotrophy-ombrotrophy (mire margin - mire expanse) gradient, and the hummock-hollow gradient. There are distinct differences in the uptake rate between various Sphagnum species and these differences seem to be due to both structural and environmental factors: (1) on individual basis the highest uptake rate is in species with large capitulum and high number of ion exchange sites i.e. lawn species, (2) on dry mass basis the most effective species are the hummock species though they have a low DM, (3) from the ecosystem point of view, hummock species with high number of shoots per unit area and high uptake rate on dry mass basis, are the most effective species in filtering available nitrogen. (1 ref.)

Potential NH{sub 4}{sup +} and NO{sub 3}{sup -} uptake on various Sphagnum species

Energy Technology Data Exchange (ETDEWEB)

Jauhiainen, J. [Joensuu Univ. (Finland). Dept. of Biology; Wallen, B.; Malmer, N. [Lund Univ. (Sweden). Dept. of Plant Ecology

1996-12-31

The objective of this research is to test differences in NH{sub 4}{sup +} and NO{sub 3}{sup -} uptake on various Sphagnum species under laboratory conditions. The studied species represent two gradients: the minerotrophy-ombrotrophy (mire margin - mire expanse) gradient, and the hummock-hollow gradient. There are distinct differences in the uptake rate between various Sphagnum species and these differences seem to be due to both structural and environmental factors: (1) on individual basis the highest uptake rate is in species with large capitulum and high number of ion exchange sites i.e. lawn species, (2) on dry mass basis the most effective species are the hummock species though they have a low DM, (3) from the ecosystem point of view, hummock species with high number of shoots per unit area and high uptake rate on dry mass basis, are the most effective species in filtering available nitrogen. (1 ref.)

Phosphorus effect on the uptake, translocation and accumulation of the 14C-urea in orchard grass (Dactylis glomerata L.)

International Nuclear Information System (INIS)

Panak, H.; Nowak, G.; Nowak, J.; Akademia Rolniczo-Technicza, Olsztyn

1981-01-01

The effect of different phosphorus supplies on the uptake, translocation and accumulation of 14 C-urea by orchard grass was investigated. Phosphorus starvation inhibits the uptake, translocation and accumulation of the carbon of urea similarly to the nitrogen of urea. As compared with the uptake process the reduction of the accumulation is much more effected by the inhibition of the carbon translocation from roots to the aboveground parts. Lack of phosphorus also decreases the incorporation of the 14 C of urea into high-molecular compounds. The effect of phosphorus deficit on the accumulation of 14 C-urea increases with time of starvation. (orig.)

RAPID NITRATE UPTAKE RATES AND LARGE SHORT-TERM STORAGE CAPACITIES MAY EXPLAIN WHY OPPORTUNISTIC GREEN MACROALGAE DOMINATE SHALLOW EUTROPHIC ESTUARIES1.

Science.gov (United States)

Kennison, Rachel L; Kamer, Krista; Fong, Peggy

2011-06-01

We quantified the effects of initial macroalgal tissue nitrogen (N) status (depleted and enriched) and varying pulses of nitrate (NO 3 - ) concentration on uptake and storage of nitrogen in Ulva intestinalis L. and Ulva expansa (Setch.) Setch. et N. L. Gardner using mesocosms modeling shallow coastal estuaries in Mediterranean climates. Uptake of NO 3 - (μmol · g dry weight [dwt] -1  · h -1 ) was measured as loss from the water after 1, 2, 4, 8, 12, and 24 h and storage as total tissue nitrogen (% dwt) and nitrate (ppm). Both species of algae exhibited a high affinity for NO 3 - across all N pulses and initial tissue contents. There was greater NO 3 - removal from the water for depleted than enriched algae across all time intervals. In the low-N-pulse treatment, U. intestinalis and U. expansa removed all measurable NO 3 - within 8 and 12 h, respectively, and in the medium and high treatments, removal was high and then decreased over time. Maximum mean uptake rates of nitrate were greater for U. expansa (∼300 μmol · g dwt -1  · h -1 ) than U. intestinalis (∼100 μmol · g dwt -1  · h -1 ); however, uptake rates were highly variable over time. Overall, U. expansa uptake rates were double those of U. intestinalis. Maximum tissue NO 3 - for U. expansa was >1,000 ppm, five times that of U. intestinalis, suggesting that U. expansa has a greater storage capacity in this cellular pool. These results showed that opportunistic green algae with differing tissue nutrient histories were able to efficiently remove nitrate from the water across a wide range of N pulses; thus, both are highly adapted to proliferate in estuarine environments with pulsed nutrient supplies. © 2011 Phycological Society of America.

Field trials show the fertilizer value of nitrogen in irrigation water

Directory of Open Access Journals (Sweden)

Mike Cahn

2017-04-01

Full Text Available Increased regulatory activity designed to protect groundwater from degradation by nitrate-nitrogen (NO3-N is focusing attention on the efficiency of agricultural use of nitrogen (N. One area drawing scrutiny is the way in which growers consider the NO3-N concentration of irrigation water when determining N fertilizer rates. Four drip-irrigated field studies were conducted in the Salinas Valley evaluating the impact of irrigation water NO3-N concentration and irrigation efficiency on the N uptake efficiency of lettuce and broccoli crops. Irrigation with water NO3-N concentrations from 2 to 45 milligrams per liter were compared with periodic fertigation of N fertilizer. The effect of irrigation efficiency was determined by comparing an efficient (110% to 120% of crop evapotranspiration, ETc and an inefficient (160% to 200% of ETc irrigation treatment. Across these trials, NO3-N from irrigation water was at least as efficiently used as fertilizer N; the uptake efficiency of irrigation water NO3-N averaged approximately 80%, and it was not affected by NO3-N concentration or irrigation efficiency.

Soil-N tagging - a method for measurement of biological nitrogen fixation in cereal-legume intercropping system

International Nuclear Information System (INIS)

Patra, D.D.; Subbiah, B.V.; Sachdev, M.S.

1985-01-01

The quantitative estimates of atmospheric dinitrogen fixed by the legume crop and transferred to the associated cereal in cereal-legume intercropping system of maize-cowpea and wheat-gram using soil and fertilizer nitrogen labelling with 15 N have been reported. The estimates of N-fixation have been compared with the similar data from A-value method. Under field conditions sole cropped cowpea fixed 53.7 per cent of its total N uptake while as intercrop with maize fixed 43.5 per cent. Maize crop got 27.6 per cent of its total N uptake by transference of the nitrogen fixed by the intercropped cowpea. In the wheat-gram intercropping system the corresponding values under greenhouse conditions were 35.0, 44.8 and 20.2 per cent, respectively. (author)

Analysis of coffee (Coffea arabica L.) performance in relation to radiation level and rate of nitrogen supply II. Uptake and distribution of nitrogen, leaf photosynthesis and first bean yields

NARCIS (Netherlands)

Bote, Adugna Debela; Zana, Zewdneh; Ocho, Fikre L.; Vos, Jan

2018-01-01

Natural supply of nitrogen is often limiting coffee production. From the viewpoints of growth and biomass production, adequate nitrogen supply is important. Growing coffee under full sunlight not only enhances potential yields but also increases demands for nitrogen fertilizer, the extent of which

Development of portable HPGe spectrometer for in situ measurements

Directory of Open Access Journals (Sweden)

Kail Artjoms

2015-01-01

Full Text Available In situ applications require a very high level of portability of high-resolution spectrometric equipment. Usage of HPGe detectors for radioactivity measurements in the environment or for nuclear safeguard applications, to combat illicit trafficking of nuclear materials or uranium and plutonium monitoring in nuclear wastes, has become a norm in the recent years. Portable HPGe-based radionuclide spectrometer with electrical cooling has lately appeared on the market for in situ applications. At the same time deterioration of energy resolution associated with vibrations produced by cryocooler or high weight of the instrument, short time of autonomous operation and high price of these spectrometers are limiting their usage in many cases. In this paper we present development results of ultra compact hand held all-in-one spectrometer for in situ measurements based on HPGe detector cooled by liquid nitrogen without listing the above disadvantages.

Reduction of nitrogen in the excretion on Japanese flounder using Ulva and Capitellid; Anaaosa to itogokai ni yoru hirame haisetsubutsuchu no chisso shori

Energy Technology Data Exchange (ETDEWEB)

Honda, H.; Kikuchi, K.; Sakaguchi, I. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

1997-03-01

To develop the culture residue treatment technique using aquatic organisms, the ammonia and nitrate uptake rates of seaweed Ulva and the nitrogen reduction rate of polychaeta annelid Captella sp. with organic sediment predaceous ability were examined in the excretion of Japanese flounder. Nitrogen uptake rate of Ulva was affected by water temperature. It was highest at 20degC, followed at 15degC and 25degC in the order. It was not affected by light intensity between 1500 and 6000 lux. Ammonia and nitrate uptake rates by Ulva were estimated to be 28.2 and 14.6 {mu}g-N/g/h at 20degC under 3000 lux, respectively. Proportion of feces excreted from Capitellid to ingested sediments was 0.38. At 25degC, Capitellid population of one thousand individuals ingested-N at the rate of 24 mg-N/day, and excreted the feces-N of Capitellid at the rate of 7 mg-N/day. About 70% of nitrogen in the sediment was reduced through this process. 15 refs., 9 figs., 13 tabs.

Nitrogen, phosphor, and potassium nutrients uptake of soybean (Glycine max (L.) Merril) on three levels of radiation intensities and soil moisture content of latosol

International Nuclear Information System (INIS)

Syahbuddin, H.; Apriyana, Y.; Heryani, N.; Darmijati, S.; Las, I.

1998-01-01

An experiment was implemented from July to August 1994 in greenhouse of the Ecophysiology Division, Bogor Research Institute for Food Crops using a split-split plot design with three replications. Radiation intensity levels as main plot were: without shelter, 25 percent shelter, and 67 percent shelter. Levels of available water in soil as sub-plot were: less than 25 percent soil water availability, content of soil water availability, and 125 percent soil water availability. Soybean varieties as sub-sub plots were: Wilis, Malabar, and Lokon. The experiment showed that nitrogen and phosphor uptake of Wilis was the highest, 41.228 mg and 1.225 mg per hill, especially under 100 percent light intensity and soil water availability more than 25 percent. Under 25 percent shade the potassium uptake of Wilis was 45.997 mg, this was higher than Malabar. The highest increased in seed dry weight, up to 0.733 g, occurred if soil water content changed from available water to 125 percent water content. One calory decreased in radiation caused 0.006 g decreased in seed dry weight per hill, Malabar variety produced an average of 0.892 g seed dry weight, where each millimeter of water will increased 2.0 mg of dry seed weight. Malabar variety had water use efficiency of 0.043 percent g/ml and radiation use efficiency 0.011 percent g/cal. Malabar variety produced the heaviest 100 good seed (7.293 g), followed by Wilis variety (5.520 g) and Lokon variety (4.597 g) [in

Phospholipase Dε enhances Braasca napus growth and seed production in response to nitrogen availability.

Science.gov (United States)

Lu, Shaoping; Yao, Shuaibing; Wang, Geliang; Guo, Liang; Zhou, Yongming; Hong, Yueyun; Wang, Xuemin

2016-03-01

Phospholipase D (PLD), which hydrolyses phospholipids to produce phosphatidic acid, has been implicated in plant response to macronutrient availability in Arabidopsis. This study investigated the effect of increased PLDε expression on nitrogen utilization in Brassica napus to explore the application of PLDε manipulation to crop improvement. In addition, changes in membrane lipid species in response to nitrogen availability were determined in the oil seed crop. Multiple PLDε over expression (PLDε-OE) lines displayed enhanced biomass accumulation under nitrogen-deficient and nitrogen-replete conditions. PLDε-OE plants in the field produced more seeds than wild-type plants but have no impact on seed oil content. Compared with wild-type plants, PLDε-OE plants were enhanced in nitrate transporter expression, uptake and reduction, whereas the activity of nitrite reductase was higher under nitrogen-depleted, but not at nitrogen-replete conditions. The level of nitrogen altered membrane glycerolipid metabolism, with greater impacts on young than mature leaves. The data indicate increased expression of PLDε has the potential to improve crop plant growth and production under nitrogen-depleted and nitrogen-replete conditions. © 2015 Society for Experimental Biology, Association of Applied Biologists and John Wiley & Sons Ltd.

Nanostructured nitrogen-doped mesoporous carbon derived from polyacrylonitrile for advanced lithium sulfur batteries

Energy Technology Data Exchange (ETDEWEB)

Liu, Ying; Zhao, Xiaohui; Chauhan, Ghanshyam S. [Department of Chemical Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 501 Jinju-daero, Jinju 660-701 (Korea, Republic of); Ahn, Jou-Hyeon, E-mail: jhahn@gnu.ac.kr [Department of Chemical Engineering and Research Institute for Green Energy Convergence Technology, Gyeongsang National University, 501 Jinju-daero, Jinju 660-701 (Korea, Republic of); Department of Materials Engineering and Convergence Technology and RIGET, Gyeongsang National University, 501 Jinju-daero, Jinju 660-701 (Korea, Republic of)

2016-09-01

Graphical abstract: Well-ordered nitrogen-doped mesoporous carbon materials were prepared by in-situ polymerization of polyacrylonitrile in SBA-15 template. The composite of sulfur and nitrogen-doped carbon was successfully used as a cathode material for lithium sulfur battery. - Highlights: • N-doped mesoporous carbons were prepared with PAN as carbon source. • Highly ordered pore system facilitates sulfur loading. • Ladder-type carbon matrix provides good structural stability for confining sulfur. • N-doping ensures an improved absorbability of soluble polysulfides. - Abstract: Nitrogen doping in carbon matrix can effectively improve the wettability of electrolyte and increase electric conductivity of carbon by ensuring fast transfer of ions. We synthesized a series of nitrogen-doped mesoporous carbons (CPANs) via in situ polymerization of polyacrylonitrile (PAN) in SBA-15 template followed by carbonization at different temperatures. Carbonization results in the formation of ladder structure which enhances the stability of the matrix. In this study, CPAN-800, carbon matrix synthesized by the carbonization at 800 °C, was found to possess many desirable properties such as high specific surface area and pore volume, moderate nitrogen content, and highly ordered mesoporous structure. Therefore, it was used to prepare S/CPAN-800 composite as cathode material in lithium sulfur (Li-S) batteries. The S/CPAN-800 composite was proved to be an excellent material for Li-S cells which delivered a high initial discharge capacity of 1585 mAh g{sup −1} and enhanced capacity retention of 862 mAh g{sup −1} at 0.1 C after 100 cycles.

Effects of nitrogen addition and fire on plant nitrogen use in a temperate steppe.

Directory of Open Access Journals (Sweden)

Hai-Wei Wei

Full Text Available Plant nitrogen (N use strategies have great implications for primary production and ecosystem nutrient cycling. Given the increasing atmospheric N deposition received by most of the terrestrial ecosystems, understanding the responses of plant N use would facilitate the projection of plant-mediated N cycling under global change scenarios. The effects of N deposition on plant N use would be affected by both natural and anthropogenic disturbances, such as prescribed fire in the grassland. We examined the effects of N addition (5.25 g N m(-2 yr(-1 and prescribed fire (annual burning on plant N concentrations and N use characters at both species and community levels in a temperate steppe of northern China. We found that N addition and fire independently affected soil N availability and plant N use traits. Nitrogen addition increased aboveground net primary productivity (ANPP, inorganic N, and N uptake, decreased N response efficiency (NRE, but did not affect biomass-weighed N concentrations at community level. Prescribed fire did not change the community level N concentrations, but largely decreased N uptake efficiency and NRE. At the species level, the effects of N addition and fire on plant N use were species-specific. The divergent responses of plant N use at community and species levels to N addition and fire highlight the importance of the hierarchical responses of plant N use at diverse biological organization levels to the alteration of soil N availability. This study will improve our understanding of the responses of plant-mediated N cycling to global change factors and ecosystem management strategies in the semiarid grasslands.

Dark hydrogen production in nitrogen atmosphere - An approach for sustainability by marine cyanobacterium Leptolyngbya valderiana BDU 20041

Energy Technology Data Exchange (ETDEWEB)

Prabaharan, D.; Arun Kumar, D.; Uma, L.; Subramanian, G. [National Facility for Marine Cyanobacteria (Sponsored by DBT, Govt. of India), Department of Marine Biotechnology, Bharathidasan University, Tiruchirapalli 620 024 (India)

2010-10-15

Biological hydrogen production is an ideal system for three main reasons i) forms a renewable energy source, ii) gives clean fuel and iii) serves as a good supplement to oil reserves. The major challenges faced in biological hydrogen production are the presence of uptake hydrogenase and lack of sustainability in the cyanobacterial hydrogen production system. Three different marine cyanobacterial species viz. Leptolyngbya valderiana BDU 20041, Dichothrix baueriana BDU 40481 and Nostoc calcicola BDU 40302 were studied for their potential use in hydrogen production. Among these, L. valderiana BDU 20041, was found to produce hydrogen even in 100% nitrogen atmosphere which was 85% of the hydrogen produced in argon atmosphere. This is the first report of such a high rate of production of hydrogen in a nitrogen atmosphere by a cyanobacterium, which makes it possible to develop sustained hydrogen production systems. L. valderiana BDU 20041, a dark hydrogen producer uses the reductant essentially supplied by the respiratory pathway for hydrogen production. Using inhibitors, this organism was found to produce hydrogen due to the activities of both nitrogenase and bidirectional hydrogenase, while it had no 'uptake' hydrogenase activity. The other two organisms though had low levels of bidirectional hydrogenase, possessed considerable 'uptake' hydrogenase activity and hence could not release much hydrogen either in argon or nitrogen atmosphere. (author)

Stimulation of microbial nitrogen cycling in aquatic ecosystems by benthic macrofauna: mechanisms and environmental implications

DEFF Research Database (Denmark)

Stief, P.

2013-01-01

(mainly nitrate and ammonium) and the emission of the greenhouse gas nitrous oxide are evaluated. Published data indicate that ecosystem engineering by sediment-burrowing macrofauna stimulates benthic nitrification and denitrification, which together allows fixed nitrogen removal. However, the release...... enhance nitrous oxide emission from shallow aquatic ecosystems. The beneficial effect of benthic macrofauna on fixed nitrogen removal through coupled nitrification-denitrification can thus be offset by the concurrent release of (i) ammonium that stimulates aquatic primary production and (ii) nitrous oxide...... of ammonium from sediments is enhanced more strongly than the sedimentary uptake of nitrate. Ecosystem engineering by reef-building macrofauna increases nitrogen retention and ammonium concentrations in shallow aquatic ecosystems, but allows organic nitrogen removal through harvesting. Grazing by macrofauna...

Effect of Thorium on Growth and Uptake of Some Elements by Maize Plant

International Nuclear Information System (INIS)

Al-Shobaki, M.E.E.

2012-01-01

A pot experiment (sand culture) was carried out to investigate the effect of thorium on maize dry matter yield, contents and uptake of N,P ,K, Na and Fe and thorium accumulation in maize plant.The pots were contaminated by thorium as Thorium Nitrate(Th (NO 3 ) 4 ,H 2 O)at concentrations 0,5,10,11,12,13,14,15 and 50 ppm. Pots irrigated by 1/10 Hogland solution for 15 days, increased tol/4 Hogland solution after that.The results show that the dry matter (shoot, root and whole plant)decreased with increasing thorium concentration in soil up to 12 ppm and slightly increased with increasing Th to 13 ppm . The Nitrogen content and its uptake decreased with increasing thorium concentration in media growth up to 11 ppm .They were slightly increased at Th concentration between 11-14 ppm in maize shoot and root. The shoots always contained N-content and uptake more than that found in roots . P- uptake decreased in both shoots and roots with increasing in thorium concentration in media growth.