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Sample records for soil production rate

  1. Soil Production and Erosion Rates and Processes in Mountainous Landscapes

    Science.gov (United States)

    Heimsath, A. M.; DiBiase, R. A.; Whipple, K. X.

    2012-12-01

    We focus here on high-relief, steeply sloped landscapes from the Nepal Himalaya to the San Gabriels of California that are typically thought to be at a critical threshold of soil cover. Observations reveal that, instead, there are significant areas mantled with soil that fit the conceptual framework of a physically mobile layer derived from the underlying parent material with some locally-derived organic content. The extent and persistence of such soils depends on the long-term balance between soil production and erosion despite the perceived discrepancy between high erosion and low soil production rates. We present cosmogenic Be-10-derived soil production and erosion rates that show that soil production increases with catchment-averaged erosion, suggesting a feedback that enhances soil-cover persistence, even in threshold landscapes. Soil production rates do decline systematically with increasing soil thickness, but hint at the potential for separate soil production functions for different erosional regimes. We also show that a process transistion to landslide-dominated erosion results in thinner, patchier soils and rockier topography, but find that there is no sudden transition to bedrock landscapes. Our landslide modeling is combined with a detailed quantification of bedrock exposure for these steep, mountainous landscapes. We also draw an important conclusion connecting the physical processes producing and transporting soil and the chemical processes weathering the parent material by measuring parent material strength across three different field settings. We observe that parent material strength increases with overlying soil thickness and, therefore, the weathered extent of the saprolite. Soil production rates, thus, decrease with increasing parent material competence. These observation highlight the importance of quantifying hillslope hydrologic processes where such multi-facted measurements are made.

  2. Quantifying the controls on potential soil production rates: a case study of the San Gabriel Mountains, California

    Directory of Open Access Journals (Sweden)

    J. D. Pelletier

    2017-08-01

    Full Text Available The potential soil production rate, i.e., the upper limit at which bedrock can be converted into transportable material, limits how fast erosion can occur in mountain ranges in the absence of widespread landsliding in bedrock or intact regolith. Traditionally, the potential soil production rate has been considered to be solely dependent on climate and rock characteristics. Data from the San Gabriel Mountains of California, however, suggest that topographic steepness may also influence potential soil production rates. In this paper I test the hypothesis that topographically induced stress opening of preexisting fractures in the bedrock or intact regolith beneath hillslopes of the San Gabriel Mountains increases potential soil production rates in steep portions of the range. A mathematical model for this process predicts a relationship between potential soil production rates and average slope consistent with published data. Once the effects of average slope are accounted for, a small subset of the data suggests that cold temperatures may limit soil production rates at the highest elevations of the range due to the influence of temperature on vegetation growth. These results suggest that climate and rock characteristics may be the sole controls on potential soil production rates as traditionally assumed but that the porosity of bedrock or intact regolith may evolve with topographic steepness in a way that enhances the persistence of soil cover in compressive-stress environments. I develop an empirical equation that relates potential soil production rates in the San Gabriel Mountains to the average slope and a climatic index that accounts for temperature limitations on soil production rates at high elevations. Assuming a balance between soil production and erosion rates on the hillslope scale, I illustrate the interrelationships among potential soil production rates, soil thickness, erosion rates, and topographic steepness that result from the

  3. Temperature response of denitrification rate and greenhouse gas production in agricultural river marginal wetland soils.

    Science.gov (United States)

    Bonnett, S A F; Blackwell, M S A; Leah, R; Cook, V; O'Connor, M; Maltby, E

    2013-05-01

    Soils are predicted to exhibit significant feedback to global warming via the temperature response of greenhouse gas (GHG) production. However, the temperature response of hydromorphic wetland soils is complicated by confounding factors such as oxygen (O2 ), nitrate (NO3-) and soil carbon (C). We examined the effect of a temperature gradient (2-25 °C) on denitrification rates and net nitrous oxide (N2 O), methane (CH4 ) production and heterotrophic respiration in mineral (Eutric cambisol and Fluvisol) and organic (Histosol) soil types in a river marginal landscape of the Tamar catchment, Devon, UK, under non-flooded and flooded with enriched NO3- conditions. It was hypothesized that the temperature response is dependent on interactions with NO3--enriched flooding, and the physicochemical conditions of these soil types. Denitrification rate (mean, 746 ± 97.3 μg m(-2)  h(-1) ), net N2 O production (mean, 180 ± 26.6 μg m(-2)  h(-1) ) and net CH4 production (mean, 1065 ± 183 μg m(-2)  h(-1) ) were highest in the organic Histosol, with higher organic matter, ammonium and moisture, and lower NO3- concentrations. Heterotrophic respiration (mean, 127 ± 4.6 mg m(-2)  h(-1) ) was not significantly different between soil types and dominated total GHG (CO2 eq) production in all soil types. Generally, the temperature responses of denitrification rate and net N2 O production were exponential, whilst net CH4 production was unresponsive, possibly due to substrate limitation, and heterotrophic respiration was exponential but limited in summer at higher temperatures. Flooding with NO3- increased denitrification rate, net N2 O production and heterotrophic respiration, but a reduction in net CH4 production suggests inhibition of methanogenesis by NO3- or N2 O produced from denitrification. Implications for management and policy are that warming and flood events may promote microbial interactions in soil between distinct microbial communities and increase

  4. Fertilizer N application rate impacts plant-soil feedback in a sanqi production system.

    Science.gov (United States)

    Wei, Wei; Yang, Min; Liu, Yixiang; Huang, Huichuan; Ye, Chen; Zheng, Jianfen; Guo, Cunwu; Hao, Minwen; He, Xiahong; Zhu, Shusheng

    2018-08-15

    Replant failure caused by negative plant-soil feedback (NPFS) in agricultural ecosystems is a critical factor restricting the development of sustainable agriculture. Soil nutrient availability has the capacity to affect plant-soil feedback. Here, we used sanqi (Panax notoginseng), which is severely threatened by NPSF, as a model plant to decipher the overall effects of nitrogen (N) rates on NPSF and the underlying mechanism. We found that a high rate of N at 450kgNha -1 (450N) aggravated the NPSF through the accumulation of pathogens in the soil compared with the optimal 250N. The increased N rates resulted in a significant increase in the soil electrical conductivity and available nitrogen but a decrease in the soil pH and C/N ratio. GeoChip 5.0 data demonstrated that these changed soil properties caused the soil to undergo stress (acidification, salinization and carbon starvation), as indicated by the enriched soil microbial gene abundances related to stress response and nutrition cycling (N, C and S). Accordingly, increased N rates reduced the richness and diversity of soil fungi and bacteria and eventually caused a shift in soil microbes from a bacterial-dominant community to a fungal-dominant community. In particular, the high 450N treatment significantly suppressed the abundance of copiotrophic bacteria, including beneficial genera Bacillus and Pseudomonas, thus weakening the antagonistic activity of these bacteria against fungal pathogens. Moreover, 450N application significantly enriched the abundance of pathogen pathogenicity-related genes. Once sanqi plants were grown in this N-stressed soil, their host-specific fungal pathogen Fusarium oxysporum significantly accumulated, which aggravated the process of NPSF. This study suggested that over-application of nitrogen is not beneficial for disease management or the reduction of fungicide application in agricultural production. Copyright © 2018 Elsevier B.V. All rights reserved.

  5. Natural and anthropogenic rates of soil erosion

    Science.gov (United States)

    Regions of land that are brought into crop production from native vegetation typically undergo a period of soil erosion instability, and long term erosion rates are greater than for natural lands as long as the land continues being used for crop production. Average rates of soil erosion under natur...

  6. Inversely estimating the vertical profile of the soil CO2 production rate in a deciduous broadleaf forest using a particle filtering method.

    Science.gov (United States)

    Sakurai, Gen; Yonemura, Seiichiro; Kishimoto-Mo, Ayaka W; Murayama, Shohei; Ohtsuka, Toshiyuki; Yokozawa, Masayuki

    2015-01-01

    Carbon dioxide (CO2) efflux from the soil surface, which is a major source of CO2 from terrestrial ecosystems, represents the total CO2 production at all soil depths. Although many studies have estimated the vertical profile of the CO2 production rate, one of the difficulties in estimating the vertical profile is measuring diffusion coefficients of CO2 at all soil depths in a nondestructive manner. In this study, we estimated the temporal variation in the vertical profile of the CO2 production rate using a data assimilation method, the particle filtering method, in which the diffusion coefficients of CO2 were simultaneously estimated. The CO2 concentrations at several soil depths and CO2 efflux from the soil surface (only during the snow-free period) were measured at two points in a broadleaf forest in Japan, and the data were assimilated into a simple model including a diffusion equation. We found that there were large variations in the pattern of the vertical profile of the CO2 production rate between experiment sites: the peak CO2 production rate was at soil depths around 10 cm during the snow-free period at one site, but the peak was at the soil surface at the other site. Using this method to estimate the CO2 production rate during snow-cover periods allowed us to estimate CO2 efflux during that period as well. We estimated that the CO2 efflux during the snow-cover period (about half the year) accounted for around 13% of the annual CO2 efflux at this site. Although the method proposed in this study does not ensure the validity of the estimated diffusion coefficients and CO2 production rates, the method enables us to more closely approach the "actual" values by decreasing the variance of the posterior distribution of the values.

  7. Fertility and productivity index rating of some soils conditioned by climate and topography

    International Nuclear Information System (INIS)

    Okae-Anti, Daniel; Imoro, Abukari Z.

    2004-10-01

    In the humid tropics, well-drained soils with abundant loose iron concretions, soils with very little weatherable minerals left and of poor chemical status due to the abundance of low activity clays, pose serious limitations to agricultural productivity. Accurate and reliable soil productivity information is needed in the form of crop yield estimates and productivity indices. We investigated the productive potential of some acrisols and plinthosols by computing productivity indices (PI) and estimating yields of four test crops, namely cowpea, groundnut, maize and soybean. PI was based on physico-chemical parameters expected to regulate air-water relations, have a role in determining the mechanical resistance to crop roots and the volume of soil, and, contribute to the fertility status of the soils. Very low Pls in the order 7.2x10 - 5, 9.6x10 - 5 and 8.32x10 - 4 were observed for Nyankpala, Changnayili and Kpelesawgu series respectively. Based on the inherently low fertility status of these soils, maize, planted as a sole crop or in rotation with groundnut is the sustainable cropping system for the soils. A return of crop residue to the soil is envisaged as a long term practice to maintain adequate levels of organic matter. (author)

  8. Linking soil DOC production rates and transport processes from landscapes to sub-basin scales

    Science.gov (United States)

    Tian, Y. Q.; Yu, Q.; Li, J.; Ye, C.

    2014-12-01

    Recent research rejects the traditional perspective that dissolved organic carbon (DOC) component in global carbon cycle are simply trivial, and in fact evidence demonstrates that lakes likely mediate carbon dynamics on a global scale. Riverine and estuarine carbon fluxes play a critical role in transporting and recycling carbon and nutrients, not only within watersheds but in their receiving waters. However, the underlying mechanisms that drive carbon fluxes, from land to rivers, lake and oceans, remain poorly understood. This presentation will report a research result of the scale-dependent DOC production rate in coastal watersheds and DOC transport processes in estuarine regions. We conducted a series of controlled experiments and field measurements for examining biogeochemical, biological, and geospatial variables that regulate downstream processing on global-relevant carbon fluxes. Results showed that increased temperatures and raised soil moistures accelerate decomposition rates of organic matter with significant variations between vegetation types. The measurements at meso-scale ecosystem demonstrated a good correlation to bulk concentration of DOC monitored in receiving waters at the outlets of sub-basins (R2 > 0.65). These field and experimental measurements improved the model of daily carbon exports through below-ground processes as a function of the organic matter content of surface soils, forest litter supply, and temperature. The study demonstrated a potential improvement in modeling the co-variance of CDOM and DOC with the unique terrestrial sources. This improvement indicated a significant promise for monitoring riverine and estuarine carbon flux from satellite images. The technical innovations include deployments of 1) mini-ecosystem (mesocosms) with soil as replicate controlled experiments for DOC production and leaching rates, and 2) aquatic mesocosms for co-variances of DOC and CDOM endmembers, and an instrumented incubation experiment for

  9. Soil Erosion Threatens Food Production

    Directory of Open Access Journals (Sweden)

    Michael Burgess

    2013-08-01

    Full Text Available Since humans worldwide obtain more than 99.7% of their food (calories from the land and less than 0.3% from the oceans and aquatic ecosystems, preserving cropland and maintaining soil fertility should be of the highest importance to human welfare. Soil erosion is one of the most serious threats facing world food production. Each year about 10 million ha of cropland are lost due to soil erosion, thus reducing the cropland available for world food production. The loss of cropland is a serious problem because the World Health Organization and the Food and Agricultural Organization report that two-thirds of the world population is malnourished. Overall, soil is being lost from agricultural areas 10 to 40 times faster than the rate of soil formation imperiling humanity’s food security.

  10. Natural and anthropogenic rates of soil erosion

    Directory of Open Access Journals (Sweden)

    Mark A. Nearing

    2017-06-01

    Full Text Available Regions of land that are brought into crop production from native vegetation typically undergo a period of soil erosion instability, and long term erosion rates are greater than for natural lands as long as the land continues being used for crop production. Average rates of soil erosion under natural, non-cropped conditions have been documented to be less than 2 Mg ha−1 yr−1. On-site rates of erosion of lands under cultivation over large cropland areas, such as in the United States, have been documented to be on the order of 6 Mg ha−1 yr−1 or more. In northeastern China, lands that were brought into production during the last century are thought to have average rates of erosion over this large area of as much as 15 Mg ha−1 yr−1 or more. Broadly applied soil conservation practices, and in particular conservation tillage and no-till cropping, have been found to be effective in reducing rates of erosion, as was seen in the United States when the average rates of erosion on cropped lands decreased from on the order of 9 Mg ha−1 yr−1 to 6 or 7 Mg ha−1 yr−1 between 1982 and 2002, coincident with the widespread adoption of new conservation tillage and residue management practices. Taking cropped lands out of production and restoring them to perennial plant cover, as was done in areas of the United States under the Conservation Reserve Program, is thought to reduce average erosion rates to approximately 1 Mg ha−1 yr−1 or less on those lands.

  11. The delicate balance between soil production and erosion, and its role on landscape evolution

    Energy Technology Data Exchange (ETDEWEB)

    Dosseto, A., E-mail: tonyd@uow.edu.au [GeoQuEST Research Centre, School of Earth and Environmental Sciences, University of Wollongong. Wollongong, NSW (Australia); Buss, Heather [US Geological Survey. Menlo Park, CA (United States); Suresh, P.O. [Department of Environment and Geography, Macquarie University. North Ryde, NSW (Australia)

    2011-06-15

    Highlights: > The uranium-series isotope composition of regolith material can be used to determine the soil residence time. > Soil residence times up to 30 and 90 kyr are calculated for Frogs Hollow and Bisley, respectively. > Production rates are relatively similar for granitic and shale lithologies, but much higher over volcanic parent rock. > Soil production matches erosion in soil-mantled landscapes, demonstrating quantitatively that this type of landscape results from a balance between these two processes > Soil production is up to two orders of magnitude slower than erosion in cultivated areas. - Abstract: The diversity in landscapes at the Earth's surface is the result, amongst other things, of the balance (or imbalance) between soil production and erosion. While erosion rates are well constrained, it is only recently that we have been able to quantify rates of soil production. Uranium-series isotopes have been useful to provide such estimates independently of erosion rates. In this study, new U-series isotope are presented data from weathering profiles developed over andesitic parent rock in Puerto Rico, and granitic bedrock in southeastern Australia. The site in Australia is located on a highland plateau, neighbouring a retreating escarpment where soil production rates between 10 and 50 mm/kyr have been determined. The results show that production rates are invariant in these two regions of Australia with values between 15 and 25 mm/kyr for the new site. Andesitic soils show much faster rates, about 200 mm/kyr. Overall, soil production rates determined with U-series isotopes range between 10 and 200 mm/kyr. This is comparable to erosion rates in soil-mantled landscapes, but faster than erosion in cratonic areas and slower than in alpine regions and cultivated areas. This suggests that soil-mantled landscapes maintain soil because they can: there is a balance between production and erosion. Similarly, thick weathering profiles develop in cratonic areas

  12. Life's Impact on the Soil Production Function

    Science.gov (United States)

    Harrison, Emma; Willenbring, Jane; Brocard, Gilles

    2016-04-01

    Soil melds life and lithology, but the top-down production of soil by the incorporation of organic matter has typically been viewed through a lens of soil biogeochemistry and the bottom-up weathering of bedrock viewed from a geomorphologic perspective. We merge these perspectives by developing a variation on the classic geomorphological soil production function [1] that accounts for the influence of top-down soil production by additions of organic material. In the classic view [1], production rate of soil from bedrock weathering is a function of the thickness of the soil horizon. Under steady state conditions, this thickness is controlled by a constant coefficient of diffusion and by the hillslope curvature. Across the globe, equilibrium landscapes can be hard to find. We explore the many ways that biota influence the upper soil horizons and move the soil-hillslope system out of steady state using measurements of in situ 10Be at depth in soil profiles. Our empirical case study is in the Luquillo Critical Zone Observatory of northeastern Puerto Rico, where long term ecological monitoring suggests an average of 375 m My-1 of litter fall [2] and as much as 17.5 m My-1 of dust [3] is contributed to the forest floor. This substantial volume of material forms an active surficial layer, functionally increasing the residence time of grains deeper in the soil profile. Litter recycling influences the cosmogenic dose rate to be higher by increasing the residence time of grains and to be lower by increasing environmental shielding. In unconstrained systems, probabilistic modeling can determine a range of solutions for the ages of grains determined with 10Be depth profiles[4]. We compare the probabilistic outcomes to actual measurements of the in situ 10Be at depth in soil profiles from the Luquillo Mountains. Life living in the soil, rather than on it, is of equal importance in the Luquillo Mountains. On average, the soil is occupied by 200 individual earthworms per m2 [5

  13. Compost amendment of sandy soil affects soil properties and greenhouse tomato productivity

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Cornelis, W.; Razzaghi, Fatemeh

    2012-01-01

    Sandy soils, with low productivity, could be improved by compost application to sustain crop production. This study aimed to examine the effect of three compost types (vegetable, fruit and yard waste compost, garden waste compost, and spent mushroom compost) on basic properties of a loamy sand...... compost had greater effect in improving tomato productivity. A decade-long application of composts on loamy sand improved basic chemical and physical properties which were reflected in increased fruit yield in tomato. Since no negative effect of compost was observed, we suggest that sandy soils may serve...... and greenhouse tomato productivity. Disturbed and intact soil samples were taken from a decade-long compost field experiment on loamy sand with three compost types at application rate of 30 m3 ha-1 yr-1 (7.5 ton ha-1 yr-1). The soils were characterized for chemical and physical properties. Tomato was planted...

  14. Litter Production and Decomposition Rate in the Reclaimed Mined Land under Albizia and Sesbania Stands and Their Effects on some Soil Chemical Properties

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    Hery Suhartoyo

    2011-01-01

    Full Text Available Vegetation establishment is considered as a critical step of mined land rehabilitation. The growing plants do not only prevent soil erosion, but also play important roles in soil ecosystem development. Their litterfall is the main process of transferring organic matter and nutrients from aboveground tree biomass to soil. Thus, its quantification would aid in understanding biomass and nutrient dynamics of the ecosystem. This study was aimed to investigate the litter production and its decomposition rate in a reclaimed mined land using albizia and sesbania, and their effects on some soil properties. The litter under each stand was biweekly collected for four months. At the same time litter samples were decomposed in mesh nylon bags in soils and the remaining litters were biweekly measured. Soil samples were taken from 0-15 cm depths from each stand for analyses of soil organic C, total N, and cation exchange capacity (CEC. The results demonstrated that total litter production under albizia (10.58 t ha-1 yr-1 was almost twice as much as that under sesbania stands (5.43 t ha-1 yr-1. Albizia litter was dominated by leaf litter (49.26% and least as understory vegetation (23.31%, whereas sesbania litter was more evenly distributed among litter types. Decomposition rates of all litters were fastest in the initial stage and then gradually decreased. Sesbania leaf litters decomposed fastest, while albizia twigs slowest. Differences in the litter production and decomposition rates of the two species had not sufficiently caused significant effects on organic-C, total N, and CEC of the soils after one year of revegetation.

  15. Impact of Corn Residue Removal on Crop and Soil Productivity

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    Johnson, J. M.; Wilhelm, W. W.; Hatfield, J. L.; Voorhees, W. B.; Linden, D.

    2003-12-01

    Over-reliance on imported fuels, increasing atmospheric levels of greenhouses and sustaining food production for a growing population are three of the most important problems facing society in the mid-term. The US Department of Energy and private enterprise are developing technology necessary to use high cellulose feedstock, such as crop residues, for ethanol production. Based on production levels, corn (Zea mays L.) residue has potential as a biofuel feedstock. Crop residues are a renewable and domestic fuel source, which can reduce the rate of fossil fuel use (both imported and domestic) and provide an additional farm commodity. Crop residues protect the soil from wind and water erosion, provide inputs to form soil organic matter (a critical component determining soil quality) and play a role in nutrient cycling. Crop residues impact radiation balance and energy fluxes and reduce evaporation. Therefore, the benefits of using crop residues as fuel, which removes crop residues from the field, must be balanced against negative environmental impacts (e.g. soil erosion), maintaining soil organic matter levels, and preserving or enhancing productivity. All ramifications of new management practices and crop uses must be explored and evaluated fully before an industry is established. There are limited numbers of long-term studies with soil and crop responses to residue removal that range from negative to negligible. The range of crop and soil responses to crop residue removal was attributed to interactions with climate, management and soil type. Within limits, corn residue can be harvested for ethanol production to provide a renewable, domestic source of energy feedstock that reduces greenhouse gases. Removal rates must vary based on regional yield, climatic conditions and cultural practices. Agronomists are challenged to develop a protocol (tool) for recommending maximum permissible removal rates that ensure sustained soil productivity.

  16. Spatial patterns and controls of soil chemical weathering rates along a transient hillslope

    Science.gov (United States)

    Yoo, K.; Mudd, S.M.; Sanderman, J.; Amundson, Ronald; Blum, A.

    2009-01-01

    Hillslopes have been intensively studied by both geomorphologists and soil scientists. Whereas geomorphologists have focused on the physical soil production and transport on hillslopes, soil scientists have been concerned with the topographic variation of soil geochemical properties. We combined these differing approaches and quantified soil chemical weathering rates along a grass covered hillslope in Coastal California. The hillslope is comprised of both erosional and depositional sections. In the upper eroding section, soil production is balanced by physical erosion and chemical weathering. The hillslope then transitions to a depositional slope where soil accumulates due to a historical reduction of channel incision at the hillslope's base. Measurements of hillslope morphology and soil thickness were combined with the elemental composition of the soil and saprolite, and interpreted through a process-based model that accounts for both chemical weathering and sediment transport. Chemical weathering of the minerals as they moved downslope via sediment transport imparted spatial variation in the geochemical properties of the soil. Inverse modeling of the field and laboratory data revealed that the long-term soil chemical weathering rates peak at 5 g m- 2 yr- 1 at the downslope end of the eroding section and decrease to 1.5 g m- 2 yr- 1 within the depositional section. In the eroding section, soil chemical weathering rates appear to be primarily controlled by the rate of mineral supply via colluvial input from upslope. In the depositional slope, geochemical equilibrium between soil water and minerals appeared to limit the chemical weathering rate. Soil chemical weathering was responsible for removing 6% of the soil production in the eroding section and 5% of colluvial influx in the depositional slope. These were among the lowest weathering rates reported for actively eroding watersheds, which was attributed to the parent material with low amount of weatherable

  17. Decreased Soil Nitrification Rate with Addition of Biochar to Acid Soils

    Institute of Scientific and Technical Information of China (English)

    Shiyu LI; Xiangshu DONG; Dandan LIU; Li LIU; Feifei HE

    2017-01-01

    This study was conducted to investigate the effects of mixed biochar on the nitrification rate in acidic soils. A 15N tracer experiment with (15NH4)2SO4 was conducted to determine the nitrification rates of 4 acidic agricultural soils with pH 4.03-6.02in Yunnan Province, Southern China. The accumulation of 15N-NO3 - and nitrification rates decreased with the addition of biochar at the end of incubation, suggesting that biochar could be a nitrification inhibitor in acidic fertilized soil. Nitrification rates in soil with pH 4.03 were evidently lower than those in soil with pH 4.81 -6.02 with or without biochar. Decreased nitrification rates were detected in the acidic soils with biochar. Soil pH controlled nitrification more than biochar in certain strongly acidic soils.

  18. Relationship between soil erodibility and modeled infiltration rate in different soils

    Science.gov (United States)

    Wang, Guoqiang; Fang, Qingqing; Wu, Binbin; Yang, Huicai; Xu, Zongxue

    2015-09-01

    The relationship between soil erodibility, which is hard to measure, and modeled infiltration rate were rarely researched. Here, the soil erodibility factors (K and Ke in the USLE, Ki and K1 in the WEPP) were calculated and the infiltration rates were modeled based on the designed laboratory simulation experiments and proposed infiltration model, in order to build their relationship. The impacts of compost amendment on the soil erosion characteristics and relationship were also studied. Two contrasting agricultural soils (bare and cultivated fluvo-aquic soils) were used, and different poultry compost contents (control, low and high) were applied to both soils. The results indicated that the runoff rate, sediment yield rate and soil erodibility of the bare soil treatments were generally higher than those of the corresponding cultivated soil treatments. The application of composts generally decreased sediment yield and soil erodibility but did not always decrease runoff. The comparison of measured and modeled infiltration rates indicated that the model represented the infiltration processes well with an N-S coefficient of 0.84 for overall treatments. Significant negative logarithmic correlations have been found between final infiltration rate (FIR) and the four soil erodibility factors, and the relationship between USLE-K and FIR demonstrated the best correlation. The application of poultry composts would not influence the logarithmic relationship between FIR and soil erodibility. Our study provided a useful tool to estimate soil erodibility.

  19. The effect of stocking rate on soil solution nitrate concentrations beneath a free-draining dairy production system in Ireland.

    Science.gov (United States)

    McCarthy, J; Delaby, L; Hennessy, D; McCarthy, B; Ryan, W; Pierce, K M; Brennan, A; Horan, B

    2015-06-01

    Economically viable and productive farming systems are required to meet the growing worldwide need for agricultural produce while at the same time reducing environmental impact. Within grazing systems of animal production, increasing concern exists as to the effect of intensive farming on potential N losses to ground and surface waters, which demands an appraisal of N flows within complete grass-based dairy farming systems. A 3-yr (2011 to 2013) whole-farm system study was conducted on a free-draining soil type that is highly susceptible to N loss under temperate maritime conditions. Soil solution concentrations of N from 3 spring-calving, grass-based systems designed to represent 3 alternative whole-farm stocking rate (SR) treatments in a post-milk quota situation in the European Union were compared: low (2.51 cows/ha), medium (2.92 cows/ha), and high SR (3.28 cows/ha). Each SR had its own farmlet containing 18 paddocks and 23 cows. Nitrogen loss from each treatment was measured using ceramic cups installed to a depth of 1m to sample the soil water. The annual and monthly average nitrate, nitrite, ammonia, and total N concentrations in soil solution collected were analyzed for each year using a repeated measures analysis. Subsequently, and based on the biological data collated from each farm system treatment within each year, the efficiency of N use was evaluated using an N balance model. Based on similar N inputs, increasing SR resulted in increased grazing efficiency and milk production per hectare. Stocking rate had no significant effect on soil solution concentrations of nitrate, nitrite, ammonia, or total N (26.0, 0.2, 2.4, and 32.3 mg/L, respectively). An N balance model evaluation of each treatment incorporating input and output data indicated that the increased grass utilization and milk production per hectare at higher SR resulted in a reduction in N surplus and increased N use efficiency. The results highlight the possibility for the sustainable

  20. Forest Soil Productivity on the Southern Long-Term Soil Productivity Sites at Age 5

    Science.gov (United States)

    D. Andrew Scott; Allan E. Tiarks; Felipe G. Sanchez; Michael Elliott-Smith; Rick Stagg

    2004-01-01

    Forest management operations have the potential to reduce soil productivity through organic matter and nutrient removal and soil compaction. We measured pine volume, bulk density, and soil and foliar nitrogen and phosphorus at age 5 on the 13 southern Long-Term Soil Productivity study sites. The treatments were organic matter removal [bole only (BO), whole tree (WT),...

  1. Determination of soil weathering rates with U-Th series disequilibria: approach on bulk soil and selected mineral phases

    International Nuclear Information System (INIS)

    Gontier, Adrien

    2014-01-01

    The aim of the present study was to evaluate weathering and soil formation rates using U-Th disequilibria in bulk soil or separated minerals. The specific objectives of this work were to evaluate the use of U-Th chronometric tools 1) regarding the impact of a land cover change and the bedrock characteristics 2) in selected secondary mineral phases and 3) in primary minerals. On the Breuil-Chenue (Morvan) site, no vegetation effect neither a grain size effect was observed on the U-Th series in the deepest soil layers (≤ 40 cm). The low soil production rate (1-2 mm/ka) is therefore more affected by regional geomorphology than by the underlying bedrock texture. In the second part of this work, based on a thorough evaluation of different techniques, a procedure was retained to extract Fe-oxides without chemical fractionation. Finally, the analysis of biotites hand-picked from one of the studied soil profile showed that U-series disequilibria allow to independently determinate the field-weathering-rate of minerals. (author)

  2. In Situ Evaluation of Crop Productivity and Bioaccumulation of Heavy Metals in Paddy Soils after Remediation of Metal-Contaminated Soils.

    Science.gov (United States)

    Kim, Shin Woong; Chae, Yooeun; Moon, Jongmin; Kim, Dokyung; Cui, Rongxue; An, Gyeonghyeon; Jeong, Seung-Woo; An, Youn-Joo

    2017-02-15

    Soils contaminated with heavy metals have been reused for agricultural, building, and industrial uses following remediation. This study assesses plant growth and bioaccumulation of heavy metals following remediation of industrially contaminated soil. The soil was collected from a field site near a nonferrous smelter and was subjected to laboratory- and field-scale studies. Soil from the contaminated site was remediated by washing with acid or mixed with soil taken from a distant uncontaminated site. The activities of various soil exoenzymes, the rate of plant growth, and the bioaccumulations of six heavy metals were measured to assess the efficacy of these bioremediation techniques. Growth of rice (Oryza sativa) was unaffected in acid-washed soil or the amended soil compared to untreated soil from the contaminated site. The levels of heavy metals in the rice kernels remained within safe limits in treated and untreated soils. Rice, sorghum (Sorghum bicolor), and wheat (Triticum aestivum) cultivated in the same soils in the laboratory showed similar growth rates. Soil exoenzyme activities and crop productivity were not affected by soil treatment in field experiments. In conclusion, treatment of industrially contaminated soil by acid washing or amendment did not adversely affect plant productivity or lead to increased bioaccumulation of heavy metals in rice.

  3. Percolation transport theory and relevance to soil formation, vegetation growth, and productivity

    Science.gov (United States)

    Hunt, A. G.; Ghanbarian, B.

    2016-12-01

    Scaling laws of percolation theory have been applied to generate the time dependence of vegetation growth rates (both intensively managed and natural) and soil formation rates. The soil depth is thus equal to the solute vertical transport distance, the soil production function, chemical weathering rates, and C and N storage rates are all given by the time derivative of the soil depth. Approximate numerical coefficients based on the maximum flow rates in soils have been proposed, leading to a broad understanding of such processes. What is now required is an accurate understanding of the variability of the coefficients in the scaling relationships. The present abstract focuses on the scaling relationship for solute transport and soil formation. A soil formation rate relates length, x, and time, t, scales, meaning that the missing coefficient must include information about fundamental space and time scales, x0 and t0. x0 is proposed to be a fundamental mineral heterogeneity scale, i.e. a median particle diameter. to is then found from the ratio of x0 and a fundamental flow rate, v0, which is identified with the net infiltration rate. The net infiltration rate is equal to precipitation P less evapotranspiration, ET, plus run-on less run-off. Using this hypothesis, it is possible to predict soil depths and formation rates as functions of time and P - ET, and the formation rate as a function of depth, soil calcic and gypsic horizon depths as functions of P-ET. It is also possible to determine when soils are in equilibrium, and predict relationships of erosion rates and soil formation rates.

  4. Production and reduction of nitrous oxide in agricultural and forest soils.

    Science.gov (United States)

    Yu, K; Chen, G; Struwe, S; Kjøller, A

    2000-06-01

    A soil-water slurry experiment was conducted to study the potentials of N2O production and reduction in denitrification of agricultural and beech forest soils in Denmark. The effects of nitrate and ammonium additions on denitrification were also investigated. The forest soil showed a higher denitrification potential than the agricultural soil. However, N2O reduction potential of the agricultural soil was higher than the beech forest soil, shown by the ratio of N2O/N2 approximately 0.11 and 3.65 in the agricultural and the beech forest soils, respectively. Both nitrate and ammonium additions stimulated the N2O production in the two soils, but reduced the N2O reduction rates in the agricultural soil slurries. In contrast to the effect on the agricultural soil, nitrate reduced the N2O reduction rate in the beech forest soil, while ammonium showed a stimulating effect on the N2O reduction activity. After one week incubation, all of the N2O produced was reduced to N2 in the agricultural soil when nitrate was still present. Nitrous oxide reduction in the beech forest soil occurred only when nitrate almost disappeared. The different nitrate inhibitory effect on the N2O reduction activity in the two soils was due to the difference in soil pH. Inhibition of nitrate on N2O reduction was significant under acidic condition. Consequently, soil could serve as a sink of atmospheric N2O under the conditions of anaerobic, pH near neutral and low nitrate content.

  5. Temperature effects on protein depolymerization and amino acid immobilization rates in soils.

    Science.gov (United States)

    Noll, Lisa; Hu, Yuntao; Zhang, Shasha; Zheng, Qing; Wanek, Wolfgang

    2017-04-01

    the three different temperatures. Amino acid concentrations and at% 15N of amino acids were measured in soil extracts at two time points by a novel approach based on the conversion of α-amino groups to N2O and purge-and-trap isotope ratio mass spectrometry. Protein availability was measured by extraction in solvents of increasing extraction efficiency (water, salt, metaphosphate, hydroxide), followed by acid hydrolysis to free amino acids and reaction with orthophthaldialdehyde. Peptidase activity was also measured at 5, 15 and 25˚ C using fluorescence probes. We expect that soil texture (clay content) and pH will affect protein sorption and availability and thereby affect depolymerization rates. Soil C:N ratios may control the N demand of microorganisms and thus affect enzyme production and amino acid immobilization rates. Moreover, soil pH is a major control on microbial community structure and may thereby affect the production of extracellular enzymes involved in protein and peptide decomposition. Due to the differences in temperature sensitivity of diffusion and enzymatic processes we expect higher temperature sensitivities given that protein decomposition is enzyme- rather than substrate-limited. This study will therefore greatly advance our understanding of major controls of the soil N cycle and provide highly important data for refining soil N cycle models.

  6. Estimates of Annual Soil Loss Rates in the State of São Paulo, Brazil

    Directory of Open Access Journals (Sweden)

    Grasiela de Oliveira Rodrigues Medeiros

    Full Text Available ABSTRACT: Soil is a natural resource that has been affected by human pressures beyond its renewal capacity. For this reason, large agricultural areas that were productive have been abandoned due to soil degradation, mainly caused by the erosion process. The objective of this study was to apply the Universal Soil Loss Equation to generate more recent estimates of soil loss rates for the state of São Paulo using a database with information from medium resolution (30 m. The results showed that many areas of the state have high (critical levels of soil degradation due to the predominance of consolidated human activities, especially in growing sugarcane and pasture use. The average estimated rate of soil loss is 30 Mg ha-1 yr-1 and 59 % of the area of the state (except for water bodies and urban areas had estimated rates above 12 Mg ha-1 yr-1, considered as the average tolerance limit in the literature. The average rates of soil loss in areas with annual agricultural crops, semi-perennial agricultural crops (sugarcane, and permanent agricultural crops were 118, 78, and 38 Mg ha-1 yr-1 respectively. The state of São Paulo requires attention to conservation of soil resources, since most soils led to estimates beyond the tolerance limit.

  7. Evaluation of soil structure in the framework of an overall soil quality rating

    DEFF Research Database (Denmark)

    Mueller, L; Shepherd, T G; Schindler, U

    2013-01-01

    Soil structure is an important aspect of agricultural soil quality, and its preservation and improvement are key to sustaining soil functions. Methods of overall soil quality assessment which include visual soil structure information can be useful tools for monitoring and managing the global soil...... resource. The aim of the paper is: (i) to demonstrate the role of visual quantification of soil structure within the procedure of the overall soil quality assessment by the Muencheberg Soil Quality Rating (M-SQR), (ii) to quantify the magnitude and variability of soil structure and overall M......-SQR on a number of agricultural research sites and (iii) to analyse the correlations of soil quality rating results with crop yields. We analysed visual soil structure and overall soil quality on a range of 20 experimental sites in seven countries. To assess visual soil structure we utilised the Visual Soil...

  8. Estimating methane gas production in peat soils of the Florida Everglades using hydrogeophysical methods

    Science.gov (United States)

    Wright, William; Comas, Xavier

    2016-04-01

    The spatial and temporal variability in production and release of greenhouse gases (such as methane) in peat soils remains uncertain, particularly for low-latitude peatlands like the Everglades. Ground penetrating radar (GPR) is a hydrogeophysical tool that has been successfully used in the last decade to noninvasively investigate carbon dynamics in peat soils; however, application in subtropical systems is almost non-existent. This study is based on four field sites in the Florida Everglades, where changes in gas content within the soil are monitored using time-lapse GPR measurements and gas releases are monitored using gas traps. A weekly methane gas production rate is estimated using a mass balance approach, considering gas content estimated from GPR, gas release from gas traps and incorporating rates of diffusion, and methanotrophic consumption from previous studies. Resulting production rates range between 0.02 and 0.47 g CH4 m-2 d-1, falling within the range reported in literature. This study shows the potential of combining GPR with gas traps to monitor gas dynamics in peat soils of the Everglades and estimate methane gas production. We also show the enhanced ability of certain peat soils to store gas when compared to others, suggesting that physical properties control biogenic gas storage in the Everglades peat soils. Better understanding biogenic methane gas dynamics in peat soils has implications regarding the role of wetlands in the global carbon cycle, particularly under a climate change scenario.

  9. Enhanced simulations of CH4 and CO2 production in permafrost-affected soils address soil moisture controls on anaerobic decomposition

    Science.gov (United States)

    Graham, D. E.; Zheng, J.; Moon, J. W.; Painter, S. L.; Thornton, P. E.; Gu, B.; Wullschleger, S. D.

    2017-12-01

    Rapid warming of Arctic ecosystems exposes soil organic carbon (SOC) to accelerated microbial decomposition, leading to increased emissions of carbon dioxide (CO2) and methane (CH4) that have a positive feedback on global warming. The magnitude, timing, and form of carbon release will depend not only on changes in temperature, but also on biogeochemical and hydrological properties of soils. In this synthesis study, we assessed the decomposability of thawed organic carbon from active layer soils and permafrost from the Barrow Environmental Observatory across different microtopographic positions under anoxic conditions. The main objectives of this study were to (i) examine environmental conditions and soil properties that control anaerobic carbon decomposition and carbon release (as both CO2 and CH4); (ii) develop a common set of parameters to simulate anaerobic CO2 and CH4 production; and (iii) evaluate uncertainties generated from representations of pH and temperature effects in the current model framework. A newly developed anaerobic carbon decomposition framework simulated incubation experiment results across a range of soil water contents. Anaerobic CO2 and CH4 production have different temperature and pH sensitivities, which are not well represented in current biogeochemical models. Distinct dynamics of CH4 production at -2° C suggest methanogen biomass and growth rate limit activity in these near-frozen soils, compared to warmer temperatures. Anaerobic CO2 production is well constrained by the model using data-informed labile carbon pool and fermentation rate initialization to accurately simulate its temperature sensitivity. On the other hand, CH4 production is controlled by water content, methanogenesis biomass, and the presence of alternative electron acceptors, producing a high temperature sensitivity with large uncertainties for methanogenesis. This set of environmental constraints to methanogenesis is likely to undergo drastic changes due to permafrost

  10. Management of soil physical properties of lowland puddled rice soil for sustainable food production

    International Nuclear Information System (INIS)

    Bhagat, R.M.

    2004-01-01

    About 3 billion people who rely on rice as their staple food today will have multiplied to some 4.4 billion by the middle of this century. With rice demand growing at an average rate of about 3 percent annually, 70 percent more rice has to be produced in next 30 years compared to present day production levels. More rice has to come from less favorable environments, with less water and nutrients. Agricultural population densities on Asia's rice producing lands are among the highest in the world and continue to increase at a remarkable rate. Rice has widely adapted itself: to the hot Australian and Egyptian deserts, to the cool Himalayan foothills of Nepal. Hill tribes in Southeast Asia plant it on slash-and-burned forest slopes; that's upland rice. However, low lying areas in Asia, which are subject to uncontrolled flooding, are home to more than 100 million poor farmers. Puddling or wet tillage in rice, decreases total soil porosity only slightly, but markedly changes porosity distribution with both storage and residual porosity increasing at the expanse of transmission porosity. Soil texture plays an important role in soil water retention following soil disturbance. Cracking pattern of the soils is studied after six years of different levels of regular addition of residue. Cracking pattern at a soil surface affects the hydrodynamic properties of soil. Cracking extends the soil-air interface into the soil profile and thereby may increase the moisture loss through evaporation

  11. Soil acidification and liming in grassland production and grassland soil fertility in Slovenia

    Directory of Open Access Journals (Sweden)

    Jure ČOP

    2015-12-01

    Full Text Available This paper reviews the evidences on grassland soil acidity and liming in relation to soil processes and herbage production. There is also an outline of the present state of soil acidity and acidity-related traits – contents of organic matter (OM, phosphorus (P and potassium (K in Slovene grassland. In grassland, soil acidification is an ongoing process under humid climate conditions. It is mainly driven by leaching of nutrients, net loss of cations due to retention in livestock products, use of physiologically acid fertilizers, acid rain and N2 fixation. This process is reduced by strong pH buffering capacity of the soil and by physiologically basic fertilizers. Acid grassland soils in Slovenia are widely distributed in spite of the fact that 44% of the total land has developed from a carbonate parent material. Of the 1713 grassland soil samples analysed during 2005-2007 45% were regarded as acid ones (pH < 5.5; in KCl, 57% as soils with very low P status (˂ 6 mg P2O5/100 g soil and 22% as soils with very low K status (˂ 10 mg K2O/100 soil. Increased content of soil organic matter was identified for alpine pastures (˃ 10 % OM in 44% of samples, mainly as a result of low decomposition rate. Liming of acid grassland soils did not always reflect in a higher herbage yield. The cause for this inefficiency is plant composition of grassland. Thus, many grassland plants with relatively high production potential have adapted to acid soil conditions. To illustrate the inconsistent liming effect three researches are reviewed. In the first two researches liming along with fertilizer application did not increase the yield comparing to the fertilized control while in the third research the increase amounted 26 %. Liming improves considerably botanical composition of the acid grassland (e.g. sward where Common Bent – Agrostis tenuis Sibth. – prevails and thus indirectly affects palatability and nutritive value of herbage. Grassland liming has a weak

  12. Soil Management for Hardwood Production

    Science.gov (United States)

    W. M. Broadfoot; B. G. Blackmon; J. B. Baker

    1971-01-01

    Soil management is the key to successful hardwood management because soil properties are probably the most important determinants of forest productivity. Because of the lack of soil uniformity, however, many foresters have become frustrated with attempts to relate soil to satisfactory growth. Since soil scientists have been unable to predict site quality for trees in...

  13. Soil quality: key for sustainable production

    Directory of Open Access Journals (Sweden)

    Stefano Mocali

    2011-02-01

    Full Text Available In the last few years several definitions of “soil quality” have been advanced, but among them the most appreciated is “the ability of soils to interact with the ecosystem in order to maintain the biological productivity, the environmental quality and to promote animal and vegetal health” as defined by Doran and Parkin in 1994. Many researchers place more emphasis on its conceptual meaning for land planning and farm management, while others consider that definition to be worth nothing in order to understand soil properties and the concept of soil quality looks like the concept of “to be suitable for”. For this reason a definition of “soil use” is needed. The food quality is characterized by several properties: the healthiness and the nutritional value, the amount of the production, the typicalness and organoleptic properties, etc.. A lot of these properties depend on environmental quality and, in particular, on soil quality. In fact soil represents the natural substrate for growth and productivity of most of the plants that live on the Hearth because they get all the essential nutritional elements from it for their own development; consequently each nutritional element present into the soil as bioavailable form for the plants is potentially destined to entry in the animal (and human food chain. In the quality process of food productive process it will be important to assure the best soil quality as possible, without any unwanted element (which will not be discussed in this note and with the right amount of fertility elements in order to guarantee the best production. In this paper the relationships between soil quality, soil biodiversity and crop sustainability will be discussed. Finally the concept of soil “biota” as nodal point for the environment regulation and the application of the indicators for soil quality will be discussed.

  14. Soil quality: key for sustainable production

    Directory of Open Access Journals (Sweden)

    Anna Benedetti

    2009-04-01

    Full Text Available In the last few years several definitions of “soil quality” have been advanced, but among them the most appreciated is “the ability of soils to interact with the ecosystem in order to maintain the biological productivity, the environmental quality and to promote animal and vegetal health” as defined by Doran and Parkin in 1994. Many researchers place more emphasis on its conceptual meaning for land planning and farm management, while others consider that definition to be worth nothing in order to understand soil properties and the concept of soil quality looks like the concept of “to be suitable for”. For this reason a definition of “soil use” is needed. The food quality is characterized by several properties: the healthiness and the nutritional value, the amount of the production, the typicalness and organoleptic properties, etc.. A lot of these properties depend on environmental quality and, in particular, on soil quality. In fact soil represents the natural substrate for growth and productivity of most of the plants that live on the Hearth because they get all the essential nutritional elements from it for their own development; consequently each nutritional element present into the soil as bioavailable form for the plants is potentially destined to entry in the animal (and human food chain. In the quality process of food productive process it will be important to assure the best soil quality as possible, without any unwanted element (which will not be discussed in this note and with the right amount of fertility elements in order to guarantee the best production. In this paper the relationships between soil quality, soil biodiversity and crop sustainability will be discussed. Finally the concept of soil “biota” as nodal point for the environment regulation and the application of the indicators for soil quality will be discussed.

  15. The effects of straw or straw-derived gasification biochar applications on soil quality and crop productivity

    DEFF Research Database (Denmark)

    Hansen, Veronika; Müller-Stöver, Dorette Sophie; Imparato, Valentina

    2017-01-01

    Thermal gasification of straw is a highly efficient technology that produces bioenergy and gasification biochar that can be used as a soil amendment, thereby returning non-renewable nutrients and stable carbon, and securing soil quality and crop productivity. A Danish on-farm field study investig......Thermal gasification of straw is a highly efficient technology that produces bioenergy and gasification biochar that can be used as a soil amendment, thereby returning non-renewable nutrients and stable carbon, and securing soil quality and crop productivity. A Danish on-farm field study...... investigated the impact of traditional straw incorporation vs. straw removal for thermal gasification bioenergy production and the application of straw gasification biochar (GB) on soil quality and crop production. Two rates of GB were applied over three successive years in which the field was cropped...... long-term effects and to identify the optimum balance between straw removal and biochar application rate....

  16. Culture-independent discovery of natural products from soil metagenomes.

    Science.gov (United States)

    Katz, Micah; Hover, Bradley M; Brady, Sean F

    2016-03-01

    Bacterial natural products have proven to be invaluable starting points in the development of many currently used therapeutic agents. Unfortunately, traditional culture-based methods for natural product discovery have been deemphasized by pharmaceutical companies due in large part to high rediscovery rates. Culture-independent, or "metagenomic," methods, which rely on the heterologous expression of DNA extracted directly from environmental samples (eDNA), have the potential to provide access to metabolites encoded by a large fraction of the earth's microbial biosynthetic diversity. As soil is both ubiquitous and rich in bacterial diversity, it is an appealing starting point for culture-independent natural product discovery efforts. This review provides an overview of the history of soil metagenome-driven natural product discovery studies and elaborates on the recent development of new tools for sequence-based, high-throughput profiling of environmental samples used in discovering novel natural product biosynthetic gene clusters. We conclude with several examples of these new tools being employed to facilitate the recovery of novel secondary metabolite encoding gene clusters from soil metagenomes and the subsequent heterologous expression of these clusters to produce bioactive small molecules.

  17. Does plant uptake or low soil mineral-N production limit mineral-N losses to surface waters and groundwater from soils under grass in summer?

    International Nuclear Information System (INIS)

    Bhatti, Ambreen; McClean, Colin J.; Cresser, Malcolm S.

    2013-01-01

    Summer minima and autumn/winter maxima in nitrate concentrations in rivers are reputedly due to high plant uptake of nitrate from soils in summer. A novel alternative hypothesis is tested here for soils under grass. By summer, residual readily mineralizable plant litter from the previous autumn/winter is negligible and fresh litter input low. Consequently little mineral-N is produced in the soil. Water-soluble and KCl-extractable mineral N in fresh soils and soils incubated outdoors for 7 days have been monitored over 12 months for soil transects at two permanent grassland sites near York, UK, using 6 replicates throughout. Vegetation-free soil is shown to produce very limited mineral-N in summer, despite the warm, moist conditions. Litter accumulates in autumn/winter and initially its high C:N ratio favours N accumulation in the soil. It is also shown that mineral-N generated monthly in situ in soil substantially exceeds the monthly mineral-N inputs via wet deposition at the sites. -- Highlights: •Soil mineral-N has been measured over a year at two grassland sites in the UK. •Rates of mineral-N production have also been measured in vegetation-free soils. •In summer, though soils were warm and moist, rate of mineral-N production was low. •The effect is attributed to low litter inputs in summer when grass is growing well. •Low mineral-N production in summer must be limiting N losses to fresh waters. -- Low mineral-N production in soils under grass limits summer N losses to surface- and ground-waters

  18. Greater carbon stocks and faster turnover rates with increasing agricultural productivity

    Science.gov (United States)

    Sanderman, J.; Fallon, S.; Baisden, T. W.

    2013-12-01

    H.H. Janzen (2006) eloquently argued that from an agricultural perspective there is a tradeoff between storing carbon as soil organic matter (SOM) and the soil nutrient and energy benefit provided during SOM mineralization. Here we report on results from the Permanent Rotation Trial at the Waite Agricultural Institute, South Australia, indicating that shifting to an agricultural management strategy which returns more carbon to the soil, not only leads to greater carbon stocks but also increases the rate of carbon cycling through the soil. The Permanent Rotation Trial was established on a red Chromosol in 1925 with upgrades made to several treatments in 1948. Decadal soil samples were collected starting in 1963 at two depths, 0-10 and 10-22.5 cm, by compositing 20 soil cores taken along the length of each plot. We have chosen to analyze five trials representing a gradient in productivity: permanent pasture (Pa), wheat-pasture rotation (2W4Pa), continuous wheat (WW), wheat-oats-fallow rotation (WOF) and wheat-fallow (WF). For each of the soil samples (40 in total), the radiocarbon activity in the bulk soil as well as size-fractionated samples was measured by accelerator mass spectrometry at ANU's Radiocarbon Dating Laboratory (Fallon et al. 2010). After nearly 70 years under each rotation, SOC stocks increased linearly with productivity data across the trials from 24 to 58 tC ha-1. Importantly, these differences were due to greater losses over time in the low productivity trials rather than gains in SOC in any of the trials. Uptake of the bomb-spike in atmospheric 14C into the soil was greatest in the trials with the greatest productivity. The coarse size fraction always had greater Δ14C values than the bulk soil samples. Several different multi-pool steady state and non-steady state models were used to interpret the Δ14C data in terms of SOC turnover rates. Regardless of model choice, either the decay rates of all pools needed to increase or the allocation of C to

  19. NOAA Soil Moisture Products System (SMOPS) Daily Blended Products

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — The Soil Moisture Operational Products System (SMOPS) combines soil moisture retrievals from multiple satellite sensors to provide a global soil moisture map with...

  20. Economic feasibility of no-tillage and manure for soil carbon sequestration in corn production in northeastern Kansas.

    Science.gov (United States)

    Pendell, Dustin L; Williams, Jeffery R; Rice, Charles W; Nelson, Richard G; Boyles, Scott B

    2006-01-01

    This study examined the economic potential of no-tillage versus conventional tillage to sequester soil carbon by using two rates of commercial N fertilizer or beef cattle manure for continuous corn (Zea mays L.) production. Yields, input rates, field operations, and prices from an experiment were used to simulate a distribution of net returns for eight production systems. Carbon release values from direct, embodied, and feedstock energies were estimated for each system, and were used with soil carbon sequestration rates from soil tests to determine the amount of net carbon sequestered by each system. The values of carbon credits that provide an incentive for managers to adopt production systems that sequester carbon at greater rates were derived. No-till systems had greater annual soil carbon gains, net carbon gains, and net returns than conventional tillage systems. Systems that used beef cattle manure had greater soil carbon gains and net carbon gains, but lower net returns, than systems that used commercial N fertilizer. Carbon credits would be needed to encourage the use of manure-fertilized cropping systems.

  1. High natural erosion rates are the backdrop for enhanced anthropogenic soil erosion in the Middle Hills of Nepal

    Science.gov (United States)

    West, A. J.; Arnold, M.; Aumaître, G.; Bourlès, D. L.; Keddadouche, K.; Bickle, M.; Ojha, T.

    2014-08-01

    Although agriculturally accelerated soil erosion is implicated in the unsustainable environmental degradation of mountain environments, such as in the Himalaya, the effects of land use can be difficult to quantify in many mountain settings because of the high and variable natural background rates of erosion. In this study, we present new long-term denudation rates, derived from cosmogenic 10Be analysis of quartz in river sediment from the Likhu Khola, a small agricultural river basin in the Middle Hills of central Nepal. Calculated long-term denudation rates, which reflect background natural erosion processes over 1000+ years prior to agricultural intensification, are similar to present-day sediment yields and to soil loss rates from terraces that are well-maintained. Similarity in short- and long-term catchment-wide erosion rates for the Likhu is consistent with data from elsewhere in the Nepal Middle Hills, but contrasts with the very large increases in short-term erosion rates seen in agricultural catchments in other steep mountain settings. Our results suggest that the large sediment fluxes exported from the Likhu and other Middle Hills rivers in the Himalaya are derived in large part from natural processes, rather than from soil erosion as a result of agricultural activity. Because of the high natural background rates, simple comparison of short- and long-term rates may not reveal unsustainable soil degradation, particularly if much of the catchment-scale erosion flux derives from mass wasting. Correcting for the mass wasting contribution in the Likhu implies minimum catchment-averaged soil production rates of ~0.25-0.35 mm yr-1. The deficit between these production rates and soil losses suggests that terraced agriculture in the Likhu may not be associated with a large systematic soil deficit, at least when terraces are well maintained, but that poorly managed terraces, forest and scrubland may lead to rapid depletion of soil resources.

  2. Evaluation of anaerobic soil disinfestation amendments and rates for conventional tomato production in Florida

    Science.gov (United States)

    Methyl bromide and other soil fumigants have been heavily relied upon to control soilborne plant pathogens, nematodes, and weeds in polyethylene-mulched vegetable production in Florida. However, negative aspects of their use on the environment and human health have increased the interest in non-chem...

  3. Nutrient accumulation and biomass production of alfafa after soil amendment with silicates

    Directory of Open Access Journals (Sweden)

    Angélica Cristina Fernandes Deus

    2014-06-01

    Full Text Available Studies on the use of silicate correctives in agriculture show that they have great potential to improve soil chemical characteristics, however, little information is available on the reactivity rates of their particle-size fractions. This study investigated whether the reactivity rates obtained experimentally could be considered in the calculation of ECC (effective calcium carbonate for soil liming, promoting adequate development of alfalfa plants. Six treatments were evaluated in the experiment, consisting of two slag types applied in two rates. The experimental ECC was used to calculate one of the rates and the ECC determined in the laboratory was used to calculate the other. Rates of limestone and wollastonite were based on the ECC determined in laboratory. The rates of each soil acidity corretive were calculated to increase the base saturation to 80%. The treatments were applied to a Rhodic Hapludox and an Alfisol Ferrudalfs. The methods for ECC determination established for lime can be applied to steel slag. The application of slag corrected soil acidity with consequent accumulation of Ca, P, and Si in alfalfa, favoring DM production.

  4. Response of the Fine Root Production, Phenology, and Turnover Rate of Six Shrub Species from a Subtropical Forest to a Soil Moisture Gradient and Shading

    Science.gov (United States)

    Fu, X.; Dai, X.; Wang, H.

    2015-12-01

    Knowledge of the fine root dynamics of different life forms in forest ecosystems is critical to understanding how the overall belowground carbon cycling is affected by climate change. However, our current knowledge regarding how endogenous or exogenous factors regulate the root dynamics of understory vegetation is limited. We selected a suite of study sites representing different habitats with gradients of soil moisture and solar radiation (shading or no shading). We assessed the fine root production phenology, the total fine root production, and the turnover among six understory shrub species in a subtropical climate, and examined the responses of the fine root dynamics to gradients in the soil moisture and solar radiation. The shrubs included three evergreen species, Loropetalum chinense, Vaccinium bracteatum, and Adinandra millettii, and three deciduous species, Serissa serissoides, Rubus corchorifolius, and Lespedeza davidii. We observed that variations in the annual fine root production and turnover among species were significant in the deciduous group but not in the evergreen group. Notably, V. bracteatum and S. serissoides presented the greatest responses in terms of root phenology to gradients in the soil moisture and shading: high-moisture habitat led to a decrease and shade led to an increase in fine root production during spring. Species with smaller fine roots of the 1st+2nd-order diameter presented more sensitive responses in terms of fine root phenology to a soil moisture gradient. Species with a higher fine root nitrogen-to -carbon ratio exhibited more sensitive responses in terms of fine root annual production to shading. Soil moisture and shading did not change the annual fine root production as much as the turnover rate. The fine root dynamics of some understory shrubs varied significantly with soil moisture and solar radiation status and may be different from tree species. Our results emphasize the need to study the understory fine root dynamics

  5. Pressure effect on rate of production of glucose-equivalent in plant ...

    Indian Academy of Sciences (India)

    Administrator

    C4 Green plants; rate of equivalent production; pressure effect. 1. Introduction ... the photosynthetic process, especially on the activa- tion and ... Section 4 deals with the effect ... the global concentrations of glyceraldehydes-3- ... chloroplast,9a a product of the maximum possible .... as soil, tissue, development stage, etc.

  6. Efficiency of sulfuric acid, mined gypsum, and two gypsum by-products in soil crusting prevention and sodic soil reclamation

    Energy Technology Data Exchange (ETDEWEB)

    Amezketa, E.; Aragues, R.; Gazol, R. [Gobierno Navarra, Pamplona (Spain). Agricultural Resources Evaluation Center

    2005-06-01

    We evaluated the efficiency of four amendments (sulfuric acid, mined-gypsum, and the by-products coal-gypsum and lacto-gypsum) in crusting prevention of two calcareous nonsodic and sodic soils and in sodic soil reclamation. Treatments for crust prevention consisted of surface-applied amendments at equivalent rates of 5 Mg pure-gypsum ha{sup -1}. Treatments for sodic soil reclamation consisted of surface-applied acid and soil-incorporated gypsums at rates of 1 pure-gypsum requirement. The efficiency of these amendments was evaluated by comparing the final infiltration rates (FIR) of the amended vs. the nonamended soils measured in disturbed-soil columns pounded with low-salinity irrigation water. Electrical conductivity (EC) and Na in the leachates of the sodic soil were measured. In the crusting prevention experiment, FIRs (mm h{sup -1) of the nonsodic soil were 21 (nonamended), 33 to 35 (gypsum materials), and 53 (sulfuric acid), whereas those for the sodic soil were 0 (nonamended), 9 (lacto-gypsum), 15 to 17 (coal- and mined-gypsum), and 21 (sulfuric acid). In the sodic-soil reclamation experiment, FIRs were 0 (nonamended), 8 to 9 (gypsum-materials), and 17 (sulfuric acid) mm h{sup -1}. All amendments were effective in crusting prevention and soil reclamation, but sulfuric acid was the most efficient due to the fastest EC and Na reductions in the leachates. The three gypsum-materials were equally effective in the reclamation process and in the nonsodic soil crusting-prevention, whereas lacto-gypsum was less efficient in the sodic-soil crusting-prevention.

  7. Soil Organic Matter and Soil Productivity: Searching for the Missing Link

    Science.gov (United States)

    Felipe G. Sanchez

    1998-01-01

    Soil-organic matter (SOM) is a complex array of components including soil fauna and flora at different stages of decomposition (Berg et al., 1982). Its concentration in soils can vary from 0.5% in mineral soils to almost 100% in peat soils (Brady, 1974). Organic matter (OM) in the surface mineral soil is considered a major determinant of forest ecosystem productivity...

  8. Chemical stabilization of cadmium in acidic soil using alkaline agronomic and industrial by-products.

    Science.gov (United States)

    Chang, Yao-Tsung; Hsi, Hsing-Cheng; Hseu, Zeng-Yei; Jheng, Shao-Liang

    2013-01-01

    In situ immobilization of heavy metals using reactive or stabilizing materials is a promising solution for soil remediation. Therefore, four agronomic and industrial by-products [wood biochar (WB), crushed oyster shell (OS), blast furnace slag (BFS), and fluidized-bed crystallized calcium (FBCC)] and CaCO3 were added to acidic soil (Cd = 8.71 mg kg(-1)) at the rates of 1%, 2%, and 4% and incubated for 90 d. Chinese cabbage (Brassica chinensis L.) was then planted in the soil to test the Cd uptake. The elevation in soil pH caused by adding the by-products produced a negative charge on the soil surface, which enhanced Cd adsorption. Consequently, the diethylenetriamine pentaacetic acid (DTPA)-extractable Cd content decreased significantly (P soil. These results from the sequential extraction procedure indicated that Cd converted from the exchangeable fraction to the carbonate or Fe-Mn oxide fraction. The long-term effectiveness of Cd immobilization caused by applying the 4 by-products was much greater than that caused by applying CaCO3. Plant shoot biomass clearly increased because of the by-product soil amendment. Cd concentration in the shoots was soil.

  9. Beta particle dose rates to micro-organisms in soil

    International Nuclear Information System (INIS)

    Kabir, M.; Spiers, F.W.; Iinuma, Takeshi.

    1977-01-01

    Studies were made to estimate the beta-particle dose rates to micro-organisms of various sizes in soil. The small insects and organisms living in soil are constantly exposed to beta-radiation arising from naturally occuring radionuclides in soil as in this case no overlying tissue shields them. The technique of measuring beta-particle dose rate consisted of using of a thin plastic scintillator to measure the pulse height distribution as the beta particle traverses the scintillator. The integrated response was determined by the number and size of the photomultiplier pulses. From the data of soil analyses it was estimated that typically about 29% of the beta particles emitted per gm. of soil were contributed by the U/Ra series, 21% by the Th series and about 50% by potassium. By combining the individual spectra of these three radionuclides in the proportion found in a typical soil, a resultant spectrum was computed representing the energy distribution of the beta particles. The dose rate received by micro-organisms of different shape and size in soil was derived from the equilibrium dose rates combined with a 'Geometrical Factor' of the organisms. For small organisms, the dose rates did not vary between the spherical and cylindrical types, but in the case of larger organisms, the dose rates were found to be greater for the spherical types of the same diameter. (auth.)

  10. Effects of land use change on soil gross nitrogen transformation rates in subtropical acid soils of Southwest China.

    Science.gov (United States)

    Xu, Yongbo; Xu, Zhihong

    2015-07-01

    Land use change affects soil gross nitrogen (N) transformations, but such information is particularly lacking under subtropical conditions. A study was carried out to investigate the potential gross N transformation rates in forest and agricultural (converted from the forest) soils in subtropical China. The simultaneously occurring gross N transformations in soil were quantified by a (15)N tracing study under aerobic conditions. The results showed that change of land use types substantially altered most gross N transformation rates. The gross ammonification and nitrification rates were significantly higher in the agricultural soils than in the forest soils, while the reverse was true for the gross N immobilization rates. The higher total carbon (C) concentrations and C / N ratio in the forest soils relative to the agricultural soils were related to the greater gross N immobilization rates in the forest soils. The lower gross ammonification combined with negligible gross nitrification rates, but much higher gross N immobilization rates in the forest soils than in the agricultural soils suggest that this may be a mechanism to effectively conserve available mineral N in the forest soils through increasing microbial biomass N, the relatively labile organic N. The greater gross nitrification rates and lower gross N immobilization rates in the agricultural soils suggest that conversion of forests to agricultural soils may exert more negative effects on the environment by N loss through NO3 (-) leaching or denitrification (when conditions for denitrification exist).

  11. Diurnal patterns of productivity of arbuscular mycorrhizal fungi revealed with the Soil Ecosystem Observatory.

    Science.gov (United States)

    Hernandez, Rebecca R; Allen, Michael F

    2013-10-01

    Arbuscular mycorrhizal (AM) fungi are the most abundant plant symbiont and a major pathway of carbon sequestration in soils. However, their basic biology, including their activity throughout a 24-h day : night cycle, remains unknown. We employed the in situ Soil Ecosystem Observatory to quantify the rates of diurnal growth, dieback and net productivity of extra-radical AM fungi. AM fungal hyphae showed significantly different rates of growth and dieback over a period of 24 h and paralleled the circadian-driven photosynthetic oscillations observed in plants. The greatest rates (and incidences) of growth and dieback occurred between noon and 18:00 h. Growth and dieback events often occurred simultaneously and were tightly coupled with soil temperature and moisture, suggesting a rapid acclimation of the external phase of AM fungi to the immediate environment. Changes in the environmental conditions and variability of the mycorrhizosphere may alter the diurnal patterns of productivity of AM fungi, thereby modifying soil carbon sequestration, nutrient cycling and host plant success. © 2013 The Authors. New Phytologist © 2013 New Phytologist Trust.

  12. VT Data - Onsite Sewage Disposal Soil Ratings

    Data.gov (United States)

    Vermont Center for Geographic Information — (Link to Metadata) ONSITE is a pre-selected subset of SSURGO certified soil data depicting onsite sewage disposal ratings of Vermont soils. The NRCS Top20 table was...

  13. A pan-Arctic synthesis of CH4 and CO2 production from anoxic soil incubations

    Science.gov (United States)

    Treat, C.C.; Natali, Susan M.; Ernakovich, Jessica; Iverson, Colleen M.; Lupasco, Massimo; McGuire, A. David; Norby, Richard J.; Roy Chowdhury, Taniya; Richter, Andreas; Šantrůčková, Hana; Schädel, C.; Schuur, Edward A.G.; Sloan, Victoria L.; Turetsky, Merritt R.; Waldrop, Mark P.

    2015-01-01

    Permafrost thaw can alter the soil environment through changes in soil moisture, frequently resulting in soil saturation, a shift to anaerobic decomposition, and changes in the plant community. These changes, along with thawing of previously frozen organic material, can alter the form and magnitude of greenhouse gas production from permafrost ecosystems. We synthesized existing methane (CH4) and carbon dioxide (CO2) production measurements from anaerobic incubations of boreal and tundra soils from the geographic permafrost region to evaluate large-scale controls of anaerobic CO2 and CH4 production and compare the relative importance of landscape-level factors (e.g., vegetation type and landscape position), soil properties (e.g., pH, depth, and soil type), and soil environmental conditions (e.g., temperature and relative water table position). We found fivefold higher maximum CH4 production per gram soil carbon from organic soils than mineral soils. Maximum CH4 production from soils in the active layer (ground that thaws and refreezes annually) was nearly four times that of permafrost per gram soil carbon, and CH4 production per gram soil carbon was two times greater from sites without permafrost than sites with permafrost. Maximum CH4 and median anaerobic CO2 production decreased with depth, while CO2:CH4 production increased with depth. Maximum CH4 production was highest in soils with herbaceous vegetation and soils that were either consistently or periodically inundated. This synthesis identifies the need to consider biome, landscape position, and vascular/moss vegetation types when modeling CH4 production in permafrost ecosystems and suggests the need for longer-term anaerobic incubations to fully capture CH4 dynamics. Our results demonstrate that as climate warms in arctic and boreal regions, rates of anaerobic CO2 and CH4 production will increase, not only as a result of increased temperature, but also from shifts in vegetation and increased

  14. The potential of residues of furfural and biogas as calcareous soil amendments for corn seed production.

    Science.gov (United States)

    Zhao, Yunchen; Yan, Zhibin; Qin, Jiahai; Ma, Zhijun; Zhang, Youfu; Zhang, Li

    2016-04-01

    Intensive corn seed production in Northwest of China produced large amounts of furfural residues, which represents higher treatment cost and environmental issue. The broad calcareous soils in the Northwest of China exhibit low organic matter content and high pH, which led to lower fertility and lower productivity. Recycling furfural residues as soil organic and nutrient amendment might be a promising agricultural practice to calcareous soils. A 3-year field study was conducted to evaluate the effects of furfural as a soil amendment on corn seed production on calcareous soil with compared to biogas residues. Soil physical-chemical properties, soil enzyme activities, and soil heavy metal concentrations were assessed in the last year after the last application. Corn yield was determined in each year. Furfural residue amendments significantly decreased soil pH and soil bulk density. Furfural residues combined with commercial fertilizers resulted in the greater cumulative on soil organic matter, total phosphorus, available phosphorus, available potassium, and cation exchange capacity than that of biogas residue. Simultaneously, urease, invertase, catalase, and alkaline phosphatase increased even at the higher furfural application rates. Maize seed yield increased even with lower furfural residue application rates. Furfural residues resulted in lower Zn concentration and higher Cd concentration than that of biogas residues. Amendment of furfural residues led to higher soil electrical conductivity (EC) than that of biogas residues. The addition of furfural residues to maize seed production may be considered to be a good strategy for recycling the waste, converting it into a potential resource as organic amendment in arid and semi-arid calcareous soils, and may help to reduce the use of mineral chemical fertilizers in these soils. However, the impact of its application on soil health needs to be established in long-term basis.

  15. North American long-term soil productivity research program

    Science.gov (United States)

    Allan E. Tiarks; Robert F. Powers; Jerry F. Ragus; Deborah S. Page-Dumroese; Felix Ponder; Douglas M. Stone

    1997-01-01

    The National Long-term Soil Productivity research program was chartered to address National Forest Management Act concerns over possible losses n soil productivity on national forest lands. The program supports validation of soil quality monitoring standards and process-level productivity research. Summarized results are supplied to forests as collected. National...

  16. Effects of rates and time of zeolite application on controlling runoff generation and soil loss from a soil subjected to a freeze-thaw cycle

    Directory of Open Access Journals (Sweden)

    Morteza Behzadfar

    2017-06-01

    Full Text Available Many factors such as freeze-thaw (FT cycle influence soil behavior. Application of soil amendments can play an important role on runoff time commencement (RT, volume (RV and soil loss (SL on soils subjected to FT cycles. However, limited studies have been documented on this subject. The present study was therefore carried out under rainfall simulation circumstances to investigate the effect of different rates of zeolite application to control the effects of FT on basic hydrological variables such as runoff production and soil loss. Towards this attempt, the effect of application of different rates of 250, 500 and 750 g m−2 of zeolite applied before, during and after the occurrence of FT cycle on RT, RV and SL was assessed in a completely randomized design. Treatments were set up in two categories viz. control (without zeolite application, and three rates and times of zeolite application in small 0.25 m2-experimental plots in three replications. The results showed that application of zeolite had significant effects on hydrological behavior of soil induced by FT cycles. Application rate of 750 g m−2 prior to FT cycle increased RT and reduced RV and SL at rates of 644%, 68% and 91%, respectively. The results also verified that zeolite could successfully mitigate the impacts of FT cycle on the main soil hydrological variables of soil profile induced by FT cycle. It is accordingly recommended to employ zeolite as an effective amendment to control soil erosion in steep and degraded rangelands where surface soil is exposed to rainfall and runoff.

  17. Production of Biochar for Soil Application

    NARCIS (Netherlands)

    Mia, Shamim; Uddin, Nijam; Mamun Hossain, Al Shaikh Abdullah; Amin, Ruhul; Mete, Fatima Z.; Hiemstra, Tjisse

    2015-01-01

    Biochar has potentials for soil fertility improvement, climate change mitigation and environmental reclamation, and charred biomass can be deliberately incorporated into soil for long-term carbon stabilization and soil amendment. Many different methods have been used for biochar production

  18. On the relative roles of hydrology, salinity, temperature, and root productivity in controlling soil respiration from coastal swamps (freshwater)

    Science.gov (United States)

    Krauss, Ken W.; Whitbeck, Julie L.; Howard, Rebecca J.

    2012-01-01

    Background and aims Soil CO2 emissions can dominate gaseous carbon losses from forested wetlands (swamps), especially those positioned in coastal environments. Understanding the varied roles of hydroperiod, salinity, temperature, and root productivity on soil respiration is important in discerning how carbon balances may shift as freshwater swamps retreat inland with sea-level rise and salinity incursion, and convert to mixed communities with marsh plants. Methods We exposed soil mesocosms to combinations of permanent flooding, tide, and salinity, and tracked soil respiration over 2 1/2 growing seasons. We also related these measurements to rates from field sites along the lower Savannah River, Georgia, USA. Soil temperature and root productivity were assessed simultaneously for both experiments. Results Soil respiration from mesocosms (22.7-1678.2 mg CO2 m-2 h-1) differed significantly among treatments during four of the seven sampling intervals, where permanently flooded treatments contributed to low rates of soil respiration and tidally flooded treatments sometimes contributed to higher rates. Permanent flooding reduced the overall capacity for soil respiration as soils warmed. Salinity did reduce soil respiration at times in tidal treatments, indicating that salinity may affect the amount of CO2 respired with tide more strongly than under permanent flooding. However, soil respiration related greatest to root biomass (mesocosm) and standing root length (field); any stress reducing root productivity (incl. salinity and permanent flooding) therefore reduces soil respiration. Conclusions Overall, we hypothesized a stronger, direct role for salinity on soil respiration, and found that salinity effects were being masked by varied capacities for increases in respiration with soil warming as dictated by hydrology, and the indirect influence that salinity can have on plant productivity.

  19. Effects of oxygen supply on the biodegradation rate in oil hydrocarbons contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Zawierucha, I [Institute of Chemistry and Environment Protection, Jan Dlugosz University of Czestochowa, Waszyngtona 4/8, 42-200 Czestochowa (Poland); Malina, G, E-mail: iwona_zawierucha@o2.pl [Faculty of Hydrogeology and Geology Engineering, Department of Geology, Geophysics and Environment Protection, AGH University of Science and Technology, Mickiewicza 30, 30-059 Cracow (Poland)

    2011-04-01

    Respirometry studies using the 10-chamber Micro-Oxymax respirometer (Columbus, Ohio) were conducted to determine the effect of biostimulation (by diverse ways of O{sub 2} supply) on enhancing biodegradation in soils contaminated with oil hydrocarbons. Soil was collected from a former military airport in Kluczewo, Poland. Oxygen was supplied by means of aerated water, aqueous solutions of H{sub 2}O{sub 2} and KMnO{sub 4}. The biodegradation was evaluated on the basis of O{sub 2} uptake and CO{sub 2} production. The O{sub 2} consumption and CO{sub 2} production rates during hydrocarbons biodegradation were estimated from the slopes of cumulative curve linear regressions. The pertinent intrinsic and enhanced biodegradation rates were calculated on the basis of mass balance equation and O{sub 2} uptake and CO{sub 2} production rates. The biodegradation rates of 5-7 times higher as compared to a control were observed when the aqueous solution of KMnO{sub 4} in concentration of 20 g L{sup -1} was applied. Permanganate is known to readily oxidize alkene carbon - carbon double bonds; so it can be successfully applied in remediation technology for soils contaminated with oil hydrocarbons. While hydrocarbons are not completely mineralized by permanganate oxidation reactions, their structure is altered by polar functional groups providing vast improvements in aqueous solubility and availability for biodegradation. The 3% aqueous solution of H{sub 2}O{sub 2} caused significant improvement of the biodegradation rates as compared to a control (on average about 260%). Aerobic biodegradation of hydrocarbons can benefit from the presence of oxygen released during H{sub 2}O{sub 2} decomposition. Adding of aerated water resulted in an increase of biodegradation rates (about 114 - 229%) as compared to a control. The aerated water can both be the source of oxygen for microorganisms and determine the transport of substrate to bacteria cells.

  20. Effects of 24 Years of Conservation Tillage Systems on Soil Organic Carbon and Soil Productivity

    Directory of Open Access Journals (Sweden)

    Kenneth R. Olson

    2013-01-01

    Full Text Available The 24-year study was conducted in southern Illinois (USA on land similar to that being removed from Conservation Reserve Program (CRP to evaluate the effects of conservation tillage systems on: (1 amount and rates of soil organic carbon (SOC storage and retention, (2 the long-term corn and soybean yields, and (3 maintenance and restoration of soil productivity of previously eroded soils. The no-till (NT plots did store and retain 7.8 Mg C ha−1 more and chisel plow (CP −1.6 Mg C ha−1 less SOC in the soil than moldboard plow (MP during the 24 years. However, no SOC sequestration occurred in the sloping and eroding NT, CP, and MP plots since the SOC level of the plot area was greater at the start of the experiment than at the end. The NT plots actually lost a total of −1.2 Mg C ha−1, the CP lost −9.9 Mg C ha−1, and the MP lost −8.2 Mg C ha−1 during the 24-year study. The long-term productivity of NT compared favorably with that of MP and CP systems.

  1. Rates of calcium carbonate removal from soils.

    NARCIS (Netherlands)

    Breemen, van N.; Protz, R.

    1988-01-01

    Mean annual rates of calcium carbonate removal from soils in a subarctic climate estimated from data on two chronosequences of calcareous storm ridges, appeared to be relatively constant through time. Concentrations of dissolved calcium carbonate in the soil solution in the study sites calculated

  2. Organic soil production from urban soil, spent mushroom substrate, and other additives

    Science.gov (United States)

    Pham, Nhung Thi Ha

    2017-09-01

    In recent years, spent mushroom substrate (SMS) is becoming the huge problem in environmental pollution issues from mushroom production. However, SMS is also a nutrient-rich ogranic material with available nutrients and high porosity. Therefore, the value of products made from SMS should be exploited to take full advantage of agricultural by-product, support organic agriculture development without environmental pollution. The research has built 5 experimental formulas (4 mixed formulas and 1 control formulas with only urban soil). The analysis results of soil samples from mixed formulas and the control formula witness a significant increase in moisture and OM of mixed formulas (moisture from 36-42%, OM from 5.5-6.9%) after 20 treatment days, and N-P-K contents are also improved remarkably. 60 days later, soil nutrients in mixed formulas continue to rise, with highest OM (8.679%) at CT1; N (0.154%) at CT4; K2O (0,698%) and P2O5 (0,172%) at CT3, in addition, heavy metal contents in all formulas are under standard limit. Synthetic assessment of all norms indicates that the best organic soil product comes from CT3. The pak choi planting experiments are performed show that the growth of plants cultivated on organic soil products made from mixed formulas are much better than plants are grown on initially soil, and they also have no pestilent insect. Specially, pak choi planted on organic soil from CT3 have sharp developing with excellent tolerance ability, quantity and area of leaves are high. Thus, CT3 is the most suitable formula to increase soil nutrients, to solve spent mushroom subtrate streament problems after harvest, and for sustainable agricultural development.

  3. Response of Microbial Soil Carbon Mineralization Rates to Oxygen Limitations

    Science.gov (United States)

    Keiluweit, M.; Denney, A.; Nico, P. S.; Fendorf, S. E.

    2014-12-01

    The rate of soil organic matter (SOM) mineralization is known to be controlled by climatic factors as well as molecular structure, mineral-organic associations, and physical protection. What remains elusive is to what extent oxygen (O2) limitations impact overall rates of microbial SOM mineralization (oxidation) in soils. Even within upland soils that are aerobic in bulk, factors limiting O2 diffusion such as texture and soil moisture can result in an abundance of anaerobic microsites in the interior of soil aggregates. Variation in ensuing anaerobic respiration pathways can further impact SOM mineralization rates. Using a combination of (first) aggregate model systems and (second) manipulations of intact field samples, we show how limitations on diffusion and carbon bioavailability interact to impose anaerobic conditions and associated respiration constraints on SOM mineralization rates. In model aggregates, we examined how particle size (soil texture) and amount of dissolved organic carbon (bioavailable carbon) affect O2 availability and distribution. Monitoring electron acceptor profiles (O2, NO3-, Mn and Fe) and SOM transformations (dissolved, particulate, mineral-associated pools) across the resulting redox gradients, we then determined the distribution of operative microbial metabolisms and their cumulative impact on SOM mineralization rates. Our results show that anaerobic conditions decrease SOM mineralization rates overall, but those are partially offset by the concurrent increases in SOM bioavailability due to transformations of protective mineral phases. In intact soil aggregates collected from soils varying in texture and SOM content, we mapped the spatial distribution of anaerobic microsites. Optode imaging, microsensor profiling and 3D tomography revealed that soil texture regulates overall O2 availability in aggregate interiors, while particulate SOM in biopores appears to control the fine-scale distribution of anaerobic microsites. Collectively, our

  4. An Overview of Production and Validation of the SMAP Passive Soil Moisture Product

    Science.gov (United States)

    Chan, S.; O'Neill, P.; Njoku, E.; Jackson, T.; Bindlish, R.

    2015-01-01

    The Soil Moisture Active Passive (SMAP) mission is an L-band mission scheduled for launch in Jan. 2015. The SMAP instruments consist of a radar and a radiometer to obtain complementary information from space for soil moisture and freeze/thaw state research and applications. By utilizing novel designs in antenna construction, retrieval algorithms, and acquisition hardware, SMAP provides a capability for global mapping of soil moisture and freeze/thaw state with unprecedented accuracy, resolution, and coverage. This improvement in hydrosphere state measurement is expected to advance our understanding of the processes that link the terrestrial water, energy and carbon cycles, improve our capability in flood prediction and drought monitoring, and enhance our skills in weather and climate forecast. For swath-based soil moisture measurement, SMAP generates three operational geophysical data products: (1) the radiometer-only soil moisture product (L2_SM_P) posted at 36-kilometer resolution, (2) the radar-only soil moisture product (L2_SM_A) posted at 3-kilometers resolution, and (3) the radar-radiometer combined soil moisture product (L2_SM_AP) posted at 9-kilometers resolution. Each product draws on the strengths of the underlying sensor(s) and plays a unique role in hydroclimatological and hydrometeorological applications. A full suite of SMAP data products is given in Table 1.

  5. Polluted soil leaching: unsaturated conditions and flow rate effects

    Directory of Open Access Journals (Sweden)

    Chourouk Mathlouthi

    2017-04-01

    Full Text Available In this study, soil samples are extracted from a polluted site at different depths. Soils texture and pollutant presence are different with depth. Preliminary analyzes showed pollution by heavy metals. To simulate soil leaching operation in static condition, a series of leaching tests are conducted in laboratory column under conditions of upflow unsaturated soil. Electrical conductivity and pH measurements on the recovered leachate are performed. Different flow rates are tested. Comparison of different profiles shows that the dissolved pollutants are concentrated in the upper soil levels and disperse weakly in the lower parts which confirm the nature of anthropogenic pollution of heavy metals. Water mobilizes a high amount of dissolved ionic substances up to 80% of the initial concentration. The increase in flow rate requires more pore volume injected to achieve the maximum clearance rate. The down flow condition extracts a small amount of dissolved substances.

  6. Toxicity of pesticides associated with potato production, including soil fumigants, to snapping turtle eggs (Chelydra serpentina).

    Science.gov (United States)

    de Solla, Shane Raymond; Palonen, Kimberley Elizabeth; Martin, Pamela Anne

    2014-01-01

    Turtles frequently oviposit in soils associated with agriculture and, thus, may be exposed to pesticides or fertilizers. The toxicity of a pesticide regime that is used for potato production in Ontario on the survivorship of snapping turtle (Chelydra serpentina) eggs was evaluated. The following treatments were applied to clean soil: 1) a mixture of the pesticides chlorothalonil, S-metolachlor, metribuzin, and chlorpyrifos, and 2) the soil fumigant metam sodium. Turtle eggs were incubated in soil in outdoor plots in which these mixtures were applied at typical and higher field application rates, where the eggs were subject to ambient temperature and weather conditions. The pesticide mixture consisting of chlorothalonil, S-metolachlor, metribuzin, and chlorpyrifos did not affect survivorship, deformities, or body size at applications up to 10 times the typical field application rates. Hatching success ranged between 87% and 100% for these treatments. Metam sodium was applied at 0.1¯ times, 0.3¯ times, 1 times, and 3 times field application rates. Eggs exposed to any application of metam sodium had 100% mortality. At typical field application rates, the chemical regime associated with potato production does not appear to have any detrimental impacts on turtle egg development, except for the use of the soil fumigant metam sodium, which is highly toxic to turtle eggs at the lowest recommended application rate. © 2013 SETAC.

  7. Effect of dairy manure rate and the stabilization time of amended soils on atrazine degradation.

    Science.gov (United States)

    Aguilera, Paula; Briceño, Gabriela; Candia, Maribel; Mora, Maria de la Luz; Demanet, Rolando; Palma, Graciela

    2009-10-01

    The application rate of liquid cow manure (LCM) in the field and the stabilization time of amended soils before application of pre-plant herbicides are factors that determine their efficiency. This study includes evaluation of residual atrazine (2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine) in soil and amended soils with equivalent rate of 100,000; 200,000; and 300,000 L ha(-1) of LCM and the effect of pre-incubation time of amended soils on atrazine degradation. The study was carried out under controlled conditions using an Andisol with previous historical application of atrazine. The respiratory activity and fluorescein diacetate (FDA) studies indicated that the time necessary for stabilization of amended soils is over 20-30 d. During the measurement of respiratory and FDA activity, no significant differences were observed when atrazine was applied. The half-life of atrazine ranged from 5 to 8d and the relative distribution of degradation products seem to be affected by the application of LCM. The pre-incubation time of amended soil and LCM dose would not affect atrazine degradation rate, when the soil has a history of herbicide application. However, repeated applications of LCM in a long period of time could change the soil pH and increase the content of dissolved organic carbon (DOC) which could further contribute to a faster degradation of atrazine. Both effects would reduce the effectiveness of atrazine in weed control.

  8. Co-production of knowledge in soils governance

    Directory of Open Access Journals (Sweden)

    Katrin Prager

    2015-06-01

    Full Text Available The co-production of knowledge between different actor groups has the potential to generate ‘more socially robust knowledge’ and better decisions, therefore improving governance processes. This paper explores knowledge co-production between different types of actors involved in soils governance in Scotland: policy makers, agency staff, scientists, local authorities, land managers and other stakeholders. In a setting characterised by network governance, we investigate knowledge co-production in three arenas that aimed to implement the Scottish Soil Framework and progress several activities such as a Soil Monitoring Action Plan and the Scotland’s Soils website. Adopting an action research, case study approach, we collected data through document analysis, observation, personal communication with policy actors involved, and semi-structured interviews with soil data users (local authorities, farmers, estate managers. The findings show different levels of interaction in the different arenas, ranging from major interaction and two-way communication to no interaction. The interaction levels indicate the extent to which knowledge exchange has taken place. Analysis highlights the divergence in problem framing between the actor groups, their diverse soil data needs and, therefore, a variation in perceptions of solutions. The combination of co-production in the different arenas enhanced policy actors’ knowledge and allowed them to reconsider policy implementation efforts. However, the delineation of knowledge types remains challenging since the same actor can hold different types of knowledge. We conclude that the concept of knowledge co-production is useful as a frame for developing polycentric, interactive and multi-party processes in soils governance, as well as to identify where interaction requires facilitation and/or improvement, but the concept does not provide a consistent theory.

  9. Utilization of maize cob biochar and rice husk charcoal as soil amendments for improving acid soil fertility and productivity

    Directory of Open Access Journals (Sweden)

    Nurhidayati

    2014-10-01

    Full Text Available The decline in soil fertility in agricultural land is a major problem that causes a decrease in the production of food crops. One of the causes of the decline in soil fertility is declining soil pH that caused the decline in the availability of nutrients in the soil. This study aimed to assess the influence of alternative liming materials derived from maize cob biochar and rice husk charcoal compared to conventional lime to improve soil pH, soil nutrient availability and maize production. The experiment used a factorial complete randomized design which consisting of two factors. The first factor is the type of soil amendment which consists of three levels (calcite lime, rice husk charcoal and cob maize biochar. The second factor is the application rates of the soil amendment consisted of three levels (3, 6 and 9 t/ha and one control treatment (without soil amendment. The results of this study showed that the application of various soil amendment increased soil pH, which the pH increase of the lime application was relatively more stable over time compared to biochar and husk charcoal. The average of the soil pH increased for each soil amendment by 23% (lime, 20% (rice husk charcoal and 23% (biochar as compared with control. The increase in soil pH can increase the availability of soil N, P and K. The greatest influence of soil pH on nutrient availability was shown by the relationship between soil pH and K nutrient availability with R2 = 0.712, while for the N by R2 = 0.462 and for the P by R2 = 0.245. The relationship between the availability of N and maize yield showed a linear equation. While the relationship between the availability of P and K with the maize yield showed a quadratic equation. The highest maize yield was found in the application of biochar and rice husk charcoal with a dose of 6-9 t/ha. The results of this study suggested that biochar and husk charcoal could be used as an alternative liming material in improving acid soil

  10. Assessment of denitrification gaseous end-products in the soil profile under two water table management practices using repeated measures analysis.

    Science.gov (United States)

    Elmi, Abdirashid A; Astatkie, Tess; Madramootoo, Chandra; Gordon, Robert; Burton, David

    2005-01-01

    The denitrification process and nitrous oxide (N2O) production in the soil profile are poorly documented because most research into denitrification has concentrated on the upper soil layer (0-0.15 m). This study, undertaken during the 1999 and 2000 growing seasons, was designed to examine the effects of water table management (WTM), nitrogen (N) application rate, and depth (0.15, 0.30, and 0.45 m) on soil denitrification end-products (N2O and N2) from a corn (Zea mays L.) field. Water table management treatments were free drainage (FD) with open drains and subirrigation (SI) with a target water table depth of 0.6 m. Fertility treatments (ammonium nitrate) were 120 kg N ha(-1) (N120) and 200 kg N ha(-1) (N200). During both growing seasons greater denitrification rates were measured in SI than in FD, particularly in the surface soil (0-0.15 m) and at the intermediate (0.15-0.30 m) soil depths under N200 treatment. Greater denitrification rates under the SI treatment, however, were not accompanied with greater N2O production. The decrease in N2O production under SI was probably caused by a more complete reduction of N2O to N2, which resulted in lower N2O to (N2O + N2) ratios. Denitrification rate, N2O production and N2O to (N2O + N2) ratios were only minimally affected by N treatments, irrespective of sampling date and soil depth. Overall, half of the denitrification occurred at the 0.15- to 0.30- and 0.30- to 0.45-m soil layers, and under SI, regardless of fertility treatment level. Consequently, sampling of the 0- to 0.15-m soil layer alone may not give an accurate estimation of denitrification losses under SI practice.

  11. High natural erosion rates are the backdrop for present-day soil erosion in the agricultural Middle Hills of Nepal

    Science.gov (United States)

    West, A. J.; Arnold, M.; AumaItre, G.; Bourles, D. L.; Keddadouche, K.; Bickle, M.; Ojha, T.

    2015-07-01

    Although agriculturally accelerated soil erosion is implicated in the unsustainable environmental degradation of mountain environments, such as in the Himalaya, the effects of land use can be challenging to quantify in many mountain settings because of the high and variable natural background rates of erosion. In this study, we present new long-term denudation rates, derived from cosmogenic 10Be analysis of quartz in river sediment from the Likhu Khola, a small agricultural river basin in the Middle Hills of central Nepal. Calculated long-term denudation rates, which reflect background natural erosion processes over 1000+ years prior to agricultural intensification, are similar to present-day sediment yields and to soil loss rates from terraces that are well maintained. Similarity in short- and long-term catchment-wide erosion rates for the Likhu is consistent with data from elsewhere in the Nepal Middle Hills but contrasts with the very large increases in short-term erosion rates seen in agricultural catchments in other steep mountain settings. Our results suggest that the large sediment fluxes exported from the Likhu and other Middle Hills rivers in the Himalaya are derived in large part from natural processes, rather than from soil erosion as a result of agricultural activity. Catchment-scale erosional fluxes may be similar over short and long timescales if both are dominated by mass wasting sources such as gullies, landslides, and debris flows (e.g., as is evident in the landslide-dominated Khudi Khola of the Nepal High Himalaya, based on compiled data). As a consequence, simple comparison of catchment-scale fluxes will not necessarily pinpoint land use effects on soils where these are only a small part of the total erosion budget, unless rates of mass wasting are also considered. Estimates of the mass wasting contribution to erosion in the Likhu imply catchment-averaged soil production rates on the order of ~ 0.25-0.35 mm yr-1, though rates of mass wasting are

  12. Production of dissolved organic carbon in forest soils along the north-south European transect

    International Nuclear Information System (INIS)

    Buzek, F.; Paces, T.; Jackova, I.

    2009-01-01

    The aim of this study is to estimate the C loss from forest soils due to the production of dissolved organic C (DOC) along a north-south European transect. Dissolved organic matter (DOM) was extracted from the forest soils incubated at a controlled temperature and water content. Soils were sampled from forest plots from Sweden to Italy. The plots represent monocultures of spruce, pine and beech and three selected chronosequences of spruce and beech spanning a range of mean annual temperature from 2 to 14 deg. C. The DOM was characterized by its DOC/DON ratio and the C isotope composition δ 13 C. The DOC/DON ratio of DOM varied from 25 to 15 after 16 days of incubation and it decreased to between 16 and 10 after 126 days. At the beginning of incubation the δ 13 C values of DOC were 1 per mille or 2 per mille less negative than incubated soils. At the end of the experiment δ 13 C of DOC were the same as soil values. In addition to DOC production heterotrophic respiration and N mineralization were measured on the incubated soils. The DON production rates decreased from 30 to 5 μgN gC -1 d -1 after 16 days of incubation to constant values from 5 to 2 μgN gC -1 d -1 after 126 days at the end of experiment. The DIN production rates were nearly constant during the experiments with values ranging from 20 to 4 μgN gC -1 d -1 . DOC production followed first-order reaction kinetics and heterotrophic respiration followed zero-order reaction kinetics. Kinetic analysis of the experimental data yielded mean annual DOC and respiration productions with respect to sites. Mean annual estimates of DOC flux varied from 3 to 29 g of C m -2 (1-19 mg C g -1 of available C), corresponding to mean DOC concentrations from 2 to 85 mg C L -1 .

  13. Production and quality of Urochloa decumbens (stapf r.d. webster forage co-related to the physical and chemical properties of the soil

    Directory of Open Access Journals (Sweden)

    Flávio Carlos Dalchiavon

    Full Text Available ABSTRACT Frequently degraded pastureland characterized by low soil fertility and compacted surface is the basic environment of Brazilian livestock. The physical and chemical characterization of soil and its co-relationship with forage production are determining factors for performance of animals raised on pasture. The objective was to analyze the forage production of Urochloa decumbens grass correlated, linearly and spatially, with physical and chemical attributes of a savannah soil in Selvíria - MS, Brazil. A geostatistical web was introduced for the collection of soil and plant data, with 120 sampling sites within an area of 56.09 ha. The descriptive analysis of the data was undertaken and linear co-relationships, both simple and multiple, were established between plant and soil properties. Semivariograms were modeled and their respective krigings and cross-validations obtained, coupled to co-krigings (plant and soil. Production of dry matter and crude protein rates of U. decumbens may be estimated by regressions and the mechanical resistance to penetration and gravimetric humidity of the soil evaluated. Since organic matter rate and the gravimetric humidity of the soil are co-related spatially with the rate of crude protein of U. decumbens, they are the best factors to calculate or increase the forage crude protein rate.

  14. Soil physical conditions in Nigerian savannas and biomass production

    International Nuclear Information System (INIS)

    Salako, F.K.

    2004-01-01

    Nigeria is located in the tropical zone, with a vast area having savanna vegetation. This is a region that is itself diverse, necessitating a classification into derived savanna, southern Guinea savanna and northern Guinea savanna. These classifications reflect environmental characteristics such as length of growing period, which for instance is 151-180 days for the northern Guinea savanna, 181-210 days for the southern Guinea savanna and 211-270 days for the derived savanna/coastal savanna. The major soils found in the various agro-ecological zones have coarse-textured surface soil, and are low in organic matter and chemical fertility. Although, yields can be improved by addition of inorganic and organic fertilizer, this can only be sustained and assured with high soil physical qualities. Soil physical qualities can be sustained at a high level with conservation tillage and soil conservation measures. Tillage is physical manipulation of the soil. Thus, the most profound effect of tillage is in relation to soil physical properties. For socio-economic and cultural reasons, manual tillage is still widely practiced in Africa as farming is largely at subsistence level. However, there are now a number of commercial farms especially for cash crop production in many parts of Africa. Many of these are located in locations which were hitherto reserved as forest and a need for sustainable production in pertinent to maintain ecological balance. Soils with coarse texture are not often sensitive to some physical parameters while some physical parameters are more relevant in a given study than others. Sustainable crop production researches in the tropics have focused on the role of planted fallows and their spatial arrangement (e.g., as in alley cropping) for many decades. Application of soil physics in the area of food production and environmental management still lags behind other sub-disciplines of soil science, particularly soil fertility in the tropics. A great challenge is

  15. SOIL ECOLOGY AS KEY TO SUSTAINABLE CROP PRODUCTION.

    Science.gov (United States)

    De Deyn, G B

    2015-01-01

    Sustainable production of food, feed and fiberwarrants sustainable soil management and crop protection. The tools available to achieve this are both in the realm of the plants and of the soil, with a key role for plant-soil interactions. At the plant level we have vast knowledge of variation within plant species with respect to pests and diseases, based on which we can breed for resistance. However, given that systems evolve this resistance is bound to be temporarily, hence also other strategies are needed. Here I plea for an integrative approach for sustainable production using ecological principles. Ecology, the study of how organisms interact with their environment, teaches us that diversity promotes productivity and yield stability. These effects are thought to be governed through resource use complementarity and reduced build-up of pests and diseases both above- and belowground. In recent years especially the role of soil biotic interactions has revealed new insights in how plant diversity and productivity are related to soil biodiversity and the functions soil biota govern. In our grassland biodiversity studies we found that root feeders can promote plant diversity and succession without reducing plant community productivity, this illustrates the role of diversity to maintain productivity. Also diversity within species offers scope for sustainable production, for example through awareness of differences between plant genotypes in chemical defense compounds that can attract natural enemies of pests aboveground- and belowground thereby providing plant protection. Plant breeding can also benefit from using complementarity between plant species in the selection for new varieties, as our work demonstrated that when growing in species mixtures plant species adapt to each other over time such that their resource acquisition traits become more complementing. Finally, in a recent meta-analysis we show that earthworms can stimulate crop yield with on average 25%, but

  16. Selenium inhibits sulfate-mediated methylmercury production in rice paddy soil.

    Science.gov (United States)

    Wang, Yong-Jie; Dang, Fei; Zhao, Jia-Ting; Zhong, Huan

    2016-06-01

    There is increasing interest in understanding factors controlling methylmercury (MeHg) production in mercury-contaminated rice paddy soil. Sulfate has been reported to affect MeHg biogeochemistry under anoxic conditions, and recent studies revealed that selenium (Se) could evidently reduce MeHg production in paddy soil. However, the controls of sulfate and Se on net MeHg production in paddy soil under fluctuating redox conditions remain largely unknown. Microcosm experiments were conducted to explore the effects of sulfate and Se on net MeHg production in rice paddy soil. Soil was added with 0-960 mg/kg sulfate, in the presence or absence of 3.0 mg/kg selenium (selenite or selenate), and incubated under anoxic (40 days) or suboxic conditions (5 days), simulating fluctuating redox conditions in rice paddy field. Sulfate addition moderately affected soil MeHg concentrations under anoxic conditions, while reoxidation resulted in evidently higher (18-40%) MeHg levels in sulfate amended soils than the control. The observed changes in net MeHg production were related to dynamics of sulfate and iron. However, Se could inhibit sulfate-mediated MeHg production in the soils: Se addition largely reduced net MeHg production in the soils (23-86%, compared to the control), despite of sulfate addition. Similarly, results of the pot experiments (i.e., rice cultivation in amended soils) indicated that soil MeHg levels were rather comparable in Se-amended soils during rice growth period, irrespective of added sulfate doses. The more important role of Se than sulfate in controlling MeHg production was explained by the formation of HgSe nanoparticles irrespective of the presence of sulfate, confirmed by TEM-EDX and XANES analysis. Our findings regarding the effects of sulfate and Se on net MeHg production in rice paddy soil together with the mechanistic explanation of the processes advance our understanding of MeHg dynamics and risk in soil-rice systems. Copyright © 2016 Elsevier

  17. Denitrification and potential nitrous oxide and carbon dioxide production in brownfield wetland soils.

    Science.gov (United States)

    Palta, Monica M; Ehrenfeld, Joan G; Groffman, Peter M

    2013-09-01

    Brownfields, previously developed sites that are derelict, vacant, or underused, are ubiquitous in urban areas. Wetlands on brownfields often retain rain and stormwater longer than the surrounding landscape because they are low-lying; this increases the possibility for these areas to process waterborne contaminants from the urban environment. In the northeastern United States, atmospheric deposition of nitrate (NO) is high. Denitrification, a microbial process common in wetlands, is a means of removing excess NO. Nitrogen gas is the desired end product of denitrification, but incomplete denitrification results in the production of NO, a greenhouse gas. The goal of this study was to investigate the potential of brownfield wetlands to serve as sinks for inorganic nitrogen and sources of greenhouse gases. We examined limitations to denitrification and NO production in brownfield wetland soils in New Jersey. Soil C:N ratios were high (18-40) and intact core denitrification (-0.78 to 11.6 μg NO-N kg dry soil d) and N mineralization (0.11-2.97 mg N kg dry soil d) were low for all sites. However, soil NO increased during dry periods. Nitrate additions to soil slurries increased denitrification rates, whereas labile C additions did not, indicating that soil denitrifiers were nitrogen limited. Incubations indicated that the end product of denitrification was primarily NO and not N. These results indicate that brownfield wetlands can develop significant denitrification capacity, potentially causing NO limitation. They might be significant sinks for atmospheric NO but may also become a significant source of NO if NO deposition were to increase. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  18. Soil compaction and fertilization in soybean productivity

    Directory of Open Access Journals (Sweden)

    Beutler Amauri Nelson

    2004-01-01

    Full Text Available Soil compaction and fertilization affect soybean development. This study evaluated the effects of soil compaction and fertilization on soybean (Glycine max cv. Embrapa 48 productivity in a Typic Haplustox under field conditions in Jaboticabal, SP, Brazil. A completely randomized design with a 5 x 2 factorial layout (compaction vs. fertilization, with four replications in each treatment, was employed. Each experimental unit (replicate consisted of a 3.6 m² useful area. After the soil was prepared by cultivation, an 11 Mg tractor passed over it a variable number of times to create five levels of compaction. Treatments were: T0= no compaction, T1= one tractor pass, T2= two, T4= four, and T6= six passes, and no fertilizer and fertilizer to give soybean yields of 2.5 to 2.9 Mg ha-1. Soil was sampled at depths of 0.02-0.05, 0.07-0.10, and 0.15-0.18 m to determine macro and microporosity, penetration resistance (PR, and bulk density (Db. After 120 days growing under these conditions, the plants were analyzed in terms of development (plant height, number of pods, shoot dry matter per plant and weight of 100 seeds and seed productivity per hectare. Soil compaction decreased soybean development and productivity, but this effect was decreased by soil fertilization, showing that such fertilization increased soybean tolerance to soil compaction.

  19. Depth-Dependent Mineral Soil CO2 Production Processes: Sensitivity to Harvesting-Induced Changes in Soil Climate.

    Science.gov (United States)

    Kellman, Lisa; Myette, Amy; Beltrami, Hugo

    2015-01-01

    Forest harvesting induces a step change in the climatic variables (temperature and moisture), that control carbon dioxide (CO2) production arising from soil organic matter decomposition within soils. Efforts to examine these vertically complex relationships in situ within soil profiles are lacking. In this study we examined how the climatic controls on CO2 production change within vertically distinct layers of the soil profile in intact and clearcut forest soils of a humid temperate forest system of Atlantic Canada. We measured mineral soil temperature (0, 5, 10, 20, 50 and 100 cm depth) and moisture (0-15 cm and 30-60 cm depth), along with CO2 surface efflux and subsurface concentrations (0, 2.5, 5, 10, 20, 35, 50, 75 and 100 cm depth) in 1 m deep soil pits at 4 sites represented by two forest-clearcut pairs over a complete annual cycle. We examined relationships between surface efflux at each site, and soil heat, moisture, and mineral soil CO2 production. Following clearcut harvesting we observed increases in temperature through depth (1-2°C annually; often in excess of 4°C in summer and spring), alongside increases in soil moisture (30%). We observed a systematic breakdown in the expected exponential relationship between CO2 production and heat with mineral soil depth, consistent with an increase in the role moisture plays in constraining CO2 production. These findings should be considered in efforts to model and characterize mineral soil organic matter decomposition in harvested forest soils.

  20. Use of alkaline flyash-based products to amend acid soils: Plant growth response and nutrient uptake

    Energy Technology Data Exchange (ETDEWEB)

    Spark, K.M.; Swift, R.S. [University of Queensland, Gatton, Qld. (Australia)

    2008-07-01

    Vast quantities of flyash are generated annually by the burning of coal in the power industry, with most of this material being stockpiled with little prospect of being utilised at present. Two alkaline flyash-based products (FAP) for use as soil amendments (FAP1 and FAP2) have been assessed using glasshouse pot trials to determine the suitability of using these products to treat acid soils. The products both contain about 80% flyash which originated from coal-fired electricity generation. The acid soils used in the study were 2 Podsols and a Ferrosol, all originating from south-east Queensland and ranging in pH (1 : 5 suspension in water) from 4 to 5.5. The flyash products when applied to the soil significantly enhanced growth of maize plants (Zea mays L.), with optimal application rates in the range 1.25-5% w/w. The FAP/soil mixtures and plants were analysed using a range of methods including extraction with DTPA, and plant biomass (aboveground dry matter). The results indicate that in addition to the liming effect, the flyash in the alkaline flyash products may enhance plant growth as a result of increasing the uptake of micro-nutrients such as copper, zinc, and manganese. The study suggests that flyash has the potential to be used as a base material in the production of soil amendment materials that can change soil pH and act as a fertiliser for certain soil micro-nutrients such as Cu, Mn, and Zn.

  1. Measurement of water flow rate in unsaturated soil by thermistor type sensor

    International Nuclear Information System (INIS)

    Takebe, Shinichi; Yamamoto, Tadatoshi; Wadachi, Yoshiki

    1981-09-01

    As a part of radiological safety studies for ground disposal of radioactive wastes, a measuring apparatus of water flow rate with thermistor type sensor was made as preliminary one and the measurement of water flow rate in the soil was carried out, in order to evalute by comparison of the migration rate of water with that of radionuclide in an unsaturated soil. The water flow rate can be determined by measuring the change of the thermal conductivity (temperature) of soil around the several thermistor type sensors set in a soil. Particularly at the region of low water content in the soil, the water flow rate was able to measure successfully by this apparatus. (author)

  2. Viral pathogen production in a wild grass host driven by host growth and soil nitrogen.

    Science.gov (United States)

    Whitaker, Briana K; Rúa, Megan A; Mitchell, Charles E

    2015-08-01

    Nutrient limitation is a basic ecological constraint that has received little attention in studies on virus production and disease dynamics. Nutrient availability could directly limit the production of viral nucleic acids and proteins, or alternatively limit host growth and thus indirectly limit metabolic pathways necessary for viral replication. In order to compare direct and indirect effects of nutrient limitation on virus production within hosts, we manipulated soil nitrogen (N) and phosphorus (P) availability in a glasshouse for the wild grass host Bromus hordeaceus and the viral pathogen Barley yellow dwarf virus-PAV. We found that soil N additions increased viral concentrations within host tissues, and the effect was mediated by host growth. Specifically, in statistical models evaluating the roles of host biomass production, leaf N and leaf P, viral production depended most strongly on host biomass, rather than the concentration of either nutrient. Furthermore, at low soil N, larger plants supported greater viral concentrations than smaller ones, whereas at high N, smaller plants supported greater viral concentrations. Our results suggest that enhanced viral productivity under N enrichment is an indirect consequence of nutrient stimulation to host growth rate. Heightened pathogen production in plants has important implications for a world facing increasing rates of nutrient deposition. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  3. Methods to quantify the impacts of water erosion on productivity of tropical soils

    International Nuclear Information System (INIS)

    Obando, Franco H

    2000-01-01

    A review on methods to quantify the impacts of water erosion on soil properties and crop yield is presented. On the basis of results of soil losses through plastic shading meshes on oxisols in the eastern plains of Colombia, the experimental design to quantify erosion induced losses in soil productivity suggested by Stocking (1985) for tropical soils is modified. With the purpose of producing contrasting levels of natural erosion, simple 33% and 45% shading rates meshes, and superposed 33% and 45% meshes were used. These were stretched out on stocking 5 m x 10 m run-off plots at 40 cm height from soil surface. Annual soil losses produced under the above mentioned shading meshes treatments did not present significant differences. It was demonstrated that 33%, 45% as well as superposed 33% and 45% produce an equivalent surface cover, CVE, greater than 90% comparable to that produced by zero grazing Brachiaria decumbens pasture. Such results allowed presenting modifications to the stocking design. It is recommended to use alternated stripes of bare soil and shading meshes of different width to produce contrasting levels of equivalent soil surface cover and consequently contrasting erosion rates. Design of the modified stocking run-off plots, including collecting channels, collecting tanks and a Geib multibox divisor are presented

  4. Hydrocarbon degradation potential in reference soils and soils contaminated with jet fuel

    International Nuclear Information System (INIS)

    Lee, R.F.; Hoeppel, R.

    1991-01-01

    Petroleum degradation in surface and subsurface soils is affected by such factors as moisture content, pH, soil type, soil organics, temperature, and oxygen concentrations. In this paper, the authors determine the degradation rates of 14 C-labeled hydrocarbons added to soils collected from a contaminated surface site, contaminated subsurface sites, and a clean reference site. The radiolabeled hydrocarbons used include benzene, toluene, naphthalene, 1-methynaphthalene, phenanthrene, fluorene, anthracene, chrysene, and hexadecane. Microbial degradation rates were based on determination of mineralization rates (production of 14 CO 2 ) of hydrocarbons that were added to soil samples. Since water was added and oxygen was not limiting, the hydrocarbon rates determined are likely to be higher than those occurring in situ. Using radiolabeled hydrocarbons, information can be provided on differences in the degradation rates of various petroleum compounds in different types of soils at a site, on possible production of petroleum metabolites in the soil, and on the importance of anaerobic petroleum degradation and the effects of nutrient, water, and surfactant addition on biodegradation rates

  5. Soil Penetration Rates by Earthworms and Plant Roots- Mechanical and Energetic Considerations

    Science.gov (United States)

    Ruiz, Siul; Schymanski, Stan; Or, Dani

    2016-04-01

    We analyze the implications of different soil burrowing rates by earthworms and growing plant roots using mechanical models that consider soil rheological properties. We estimate the energetic requirements for soil elasto-viscoplastic displacement at different rates for similar burrows and water contents. In the core of the mechanical model is a transient cavity expansion into viscoplastic wet soil that mimic an earthworm or root tip cone-like penetration and subsequent cavity expansion due to pressurized earthworm hydrostatic skeleton or root radial growth. Soil matrix viscoplatic considerations enable separation of the respective energetic requirements for earthworms penetrating at 2 μm/s relative to plant roots growing at 0.2 μm/s . Typical mechanical and viscous parameters are obtained inversely for soils under different fixed water contents utilizing custom miniaturized cone penetrometers at different fixed penetration rates (1 to 1000 μm/s). Experimental results determine critical water contents where soil exhibits pronounced viscoplatic behavior (close to saturation), bellow which the soil strength limits earthworms activity and fracture propagation by expanding plant roots becomes the favorable mechanical mode. The soil mechanical parameters in conjunction with earthworm and plant root physiological pressure limitations (200 kPa and 2000 kPa respectively) enable delineation of the role of soil saturation in regulating biotic penetration rates for different soil types under different moisture contents. Furthermore, this study provides a quantitative framework for estimating rates of energy expenditure for soil penetration, which allowed us to determine maximum earthworm population densities considering soil mechanical properties and the energy stored in soil organic matter.

  6. Reassessment of soil erosion on the Chinese loess plateau: were rates overestimated?

    Science.gov (United States)

    Zhao, Jianlin; Govers, Gerard

    2014-05-01

    Several studies have estimated regional soil erosion rates (rill and interrill erosion) on the Chinese loess plateau using an erosion model such as the RUSLE (e.g. Fu et al., 2011; Sun et al., 2013). However, the question may be asked whether such estimates are realistic: studies have shown that the use of models for large areas may lead to significant overestimations (Quinton et al., 2010). In this study, soil erosion rates on the Chinese loess plateau were reevaluated by using field measured soil erosion data from erosion plots (216 plots and 1380 plot years) in combination with a careful extrapolation procedure. Data analysis showed that the relationship between slope and erosion rate on arable land could be well described by erosion-slope relationships reported in the literature (Nearing, 1997). The increase of average erosion rate with slope length was clearly degressive, as could be expected from earlier research. However, for plots with permanent vegetation (grassland, shrub, forest) no relationship was found between erosion rates and slope gradient and/or slope length. This is important, as it implies that spatial variations of erosion on permanently vegetated areas cannot be modeled using topographical functions derived from observations on arable land. Application of relationships developed for arable land will lead to a significant overestimation of soil erosion rates. Based on our analysis we estimate the total soil erosion rate in the Chinese Loess plateau averages ca. 6.78 t ha-1 yr-1 for the whole loess plateau, resulting in a total sediment mobilisation of ca. 0.38 Gt yr-1. Erosion rates on arable land average ca. 15.10 t ha-1 yr-1. These estimates are 2 to 3 times lower than previously published estimates. The main reason why previous estimates are likely to be too high is that the values of (R)USLE parameters such as K, P and LS factor were overestimated. Overestimations of the K factor are due to the reliance of nomograph calculations, resulting

  7. Unit soil loss rate from various construction sites during a storm.

    Science.gov (United States)

    Maniquiz, Marla C; Lee, Soyoung; Lee, Eunju; Kong, Dong-Soo; Kim, Lee-Hyung

    2009-01-01

    The Korean Ministry of Environment (MOE) opts to establish an ordinance having a standard specifying an allowable soil loss rate applicable to construction projects. The predicted amount of soil loss from a construction site exceeding the standard can be used to calculate the percent reduction necessary to comply with the ordinance. This research was conducted to provide a basis to establish a standard by investigating the unit soil loss rates in the three phases of development: pre-construction, active construction and post construction based from 1,036 Environmental Impact Assessment (EIA) reports within the six-year period (2000-2005). Based on the findings, several factors affect the magnitude of soil loss rates particularly storm characteristics, site slope, soil type, location from rivers, as well as the type of construction activity. In general, the unit soil loss rates during the active construction phase are extremely higher in comparison to undisturbed areas; in magnitude of 7 to 80 times larger in urban areas and 18 to 585 times in rural areas. Only between 20 to 40 percent of the soil loss rates was contributed at pre- and post- construction phases indicating that the active construction phase is the most important phase to control.

  8. Effect of Irrigation Water Type on Infiltration Rates of Sandy Soil

    International Nuclear Information System (INIS)

    Al-Omran, A.M.; Al-Matrood, S.M.; Choudhary, M.I.

    2004-01-01

    A laboratory experiment was conducted to test the effect of three water types (tap water, well water and sewage water) on the infiltration rate of three soils varying in texture (sand. loamy sand and sandy loam). A stationary rainfall simulator dispensing water at a rate of 45 mm h-1, connected to the different sources of water, was used to measure the infiltration rates. A total of 5 runs were carried out using each water quality. The volume of runoff against the time was recorded at each 5 minute interval. The infiltration rate was calculated as the difference between the water applied and the excesses water measured as surface runoff. Infiltration rate at first run were rapid in all the three soils and then progressively declined as the number of runs increased. The same trend was observed for each water quality tested. The reduction in infiltration rate with increasing number of runs for prewetted surface than for the initial dry surface was attributed to break down and settling of fine particles that took place earlier during prewetting. The infiltration curves for all the three soils when irrigared with different qualities of water was not distinguishable. The relationship between infiltration rate as function of time for the treatments applied were tested using Kostiakov equation I=bt-n. The infiltration data gave a coefficient of determination R2 >0.90 for all the treatments. The infiltration parameters B, and n varied strongly with respect to soil texture. Values of B decreased with changing soil textures, being highest for the sandy soil, and lowest for the sandy loamy soil, whereas n values showed the opposite trend. It was concluded that effect of soil texture on the infiltration rate was very pronounced while water qualities showed a little effect. (author)

  9. Influence of Pyrolysis Temperature and Production Conditions on Switchgrass Biochar for Use as a Soil Amendment

    Directory of Open Access Journals (Sweden)

    Amanda Joy Ashworth

    2014-10-01

    Full Text Available Biochars form recalcitrant carbon and increase water and nutrient retention in soils; however, the magnitude is contingent upon production conditions and thermo-chemical conversion processes. Herein we aim at (i characterizing switchgrass (Panicum virgatum L.-biochar morphology, (ii estimating water-holding capacity under increasing ratios of char: soil; and, (iii determining nutrient profile variation as a function of pyrolysis conversion methodologies (i.e. continuous, auger pyrolysis system versus batch pyrolysis systems for terminal use as a soil amendment. Auger system chars produced at 600°C had the greatest lignin portion by weight among the biochars produced from the continuous system. On the other hand, a batch pyrolysis system (400 °C – 3h yielded biochar with 73.10% lignin (12 fold increases, indicating higher recalcitrance, whereas lower production temperatures (400 °C yielded greater hemicellulose (i.e. greater mineralization promoting substrate. Under both pyrolysis methods, increasing biochar soil application rates resulted in linear decreases in bulk density (g cm-3. Increases in auger-char (400 °C applications increased soil water-holding capacities; however, application rates of >2 Mt ha-1 are required. Pyrolysis batch chars did not influence water-holding abilities (P>0.05. Biochar macro and micronutrients increased, as the pyrolysis temperature increased in the auger system from 400 to 600 °C, and the residence time increased in the batch pyrolysis system from 1 to 3 h. Conversely, nitrogen levels tended to decrease under the two previously mentioned conditions. Consequently, not all chars are inherently equal, in that varying operation systems, residence times, and production conditions greatly affect uses as a soil amendment and overall rate of efficacy.

  10. Soil Erosion and Agricultural Sustainability

    Science.gov (United States)

    Montgomery, D. R.

    2009-04-01

    Data drawn from a global compilation of studies support the long articulated contention that erosion rates from conventionally plowed agricultural fields greatly exceed rates of soil production, erosion under native vegetation, and long-term geological erosion. Whereas data compiled from around the world show that soil erosion under conventional agriculture exceeds both rates of soil production and geological erosion rates by up to several orders of magnitude, similar global distributions of soil production and geological erosion rates suggest an approximate balance. Net soil erosion rates in conventionally plowed fields on the order of 1 mm/yr can erode typical hillslope soil profiles over centuries to millennia, time-scales comparable to the longevity of major civilizations. Well-documented episodes of soil loss associated with agricultural activities date back to the introduction of erosive agricultural methods in regions around the world, and stratigraphic records of accelerated anthropogenic soil erosion have been recovered from lake, fluvial, and colluvial stratigraphy, as well as truncation of soil stratigraphy (such as truncated A horizons). A broad convergence in the results from studies based on various approaches employed to study ancient soil loss and rates of downstream sedimentation implies that widespread soil loss has accompanied human agricultural intensification in examples drawn from around the world. While a broad range of factors, including climate variability and society-specific social and economic contexts — such as wars or colonial relationships — all naturally influence the longevity of human societies, the ongoing loss of topsoil inferred from studies of soil erosion rates in conventional agricultural systems has obvious long-term implications for agricultural sustainability. Consequently, modern agriculture — and therefore global society — faces a fundamental question over the upcoming centuries. Can an agricultural system

  11. Assessment of the SMAP Passive Soil Moisture Product

    Science.gov (United States)

    Chan, Steven K.; Bindlish, Rajat; O'Neill, Peggy E.; Njoku, Eni; Jackson, Tom; Colliander, Andreas; Chen, Fan; Burgin, Mariko; Dunbar, Scott; Piepmeier, Jeffrey; hide

    2016-01-01

    The National Aeronautics and Space Administration (NASA) Soil Moisture Active Passive (SMAP) satellite mission was launched on January 31, 2015. The observatory was developed to provide global mapping of high-resolution soil moisture and freeze-thaw state every two to three days using an L-band (active) radar and an L-band (passive) radiometer. After an irrecoverable hardware failure of the radar on July 7, 2015, the radiometer-only soil moisture product became the only operational Level 2 soil moisture product for SMAP. The product provides soil moisture estimates posted on a 36 kilometer Earth-fixed grid produced using brightness temperature observations from descending passes. Within months after the commissioning of the SMAP radiometer, the product was assessed to have attained preliminary (beta) science quality, and data were released to the public for evaluation in September 2015. The product is available from the NASA Distributed Active Archive Center at the National Snow and Ice Data Center. This paper provides a summary of the Level 2 Passive Soil Moisture Product (L2_SM_P) and its validation against in situ ground measurements collected from different data sources. Initial in situ comparisons conducted between March 31, 2015 and October 26, 2015, at a limited number of core validation sites (CVSs) and several hundred sparse network points, indicate that the V-pol Single Channel Algorithm (SCA-V) currently delivers the best performance among algorithms considered for L2_SM_P, based on several metrics. The accuracy of the soil moisture retrievals averaged over the CVSs was 0.038 cubic meter per cubic meter unbiased root-mean-square difference (ubRMSD), which approaches the SMAP mission requirement of 0.040 cubic meter per cubic meter.

  12. Production and morphological components of sunflower on soil fertilized with cassava wastewater

    Directory of Open Access Journals (Sweden)

    Mara Suyane Marques Dantas

    Full Text Available ABSTRACT Agroindustrial residues, such as cassava wastewater, have been used as soil fertilizers, reducing environmental pollution and recovering nutrients. The objective of this work was to evaluate production and morphological components and oil yield of sunflower (Helianthus annuus, hybrid Helio-250, fertilized with cassava wastewater. The experiment was conducted at the Experimental Station of the Instituto Agronomico de Pernambuco, Vitória de Santo Antão, State of Pernambuco, Brazil. A randomized block experimental design was used, with six cassava wastewater rates (0, 8.5, 17.0, 34.0, 68.0 and 136 m3 ha-1 and four replications. The variables evaluated were shoot fresh and dry weight, capitulum fresh and dry weight, capitulum diameter, seed yield, oil yield and seed oil content. The use cassava wastewater as soil fertilizer improved the production and morphological variables evaluated, except the seed oil content, which decreased with application of cassava wastewater rates above 25 m3 ha-1.

  13. Ammonium sorption and ammonia inhibition of nitrite-oxidizing bacteria explain contrasting soil N2O production

    Science.gov (United States)

    Venterea, R. T.; Sadowsky, M.; Breuillin-Sessoms, F.; Wang, P.; Clough, T. J.; Coulter, J. A.

    2015-12-01

    Better understanding of process controls over nitrous oxide (N2O) production in urine-impacted 'hot spots' and fertilizer bands is needed to improve mitigation strategies and emission models. Following amendment with bovine (Bos taurus) urine (Bu) or urea (Ur), we measured inorganic N, pH, N2O, and genes associated with nitrification in two soils ('L' and 'W') having similar texture, pH, C, and C/N ratio. Solution-phase ammonia (slNH3) was also calculated accounting for non-linear ammonium (NH4+) sorption capacities (ASC). Soil W displayed greater nitrification rates and nitrate (NO3-) levels than soil L, but was more resistant to nitrite (NO2-) accumulation and produced two to ten times less N2O than soil L. Genes associated with NO2- oxidation (nxrA) increased substantially in soil W but remained static in soil L. Soil NO2- was strongly correlated with N2O production, and cumulative (c-) slNH3 explained 87% of the variance in c-NO2-. Differences between soils were explained by greater slNH3 in soil L which inhibited NO2- oxidization leading to greater NO2- levels and N2O production. This is the first study to correlate the dynamics of soil slNH3, NO2-, N2O and nitrifier genes, and the first to show how ASC can regulate NO2- levels and N2O production.

  14. Estimating Infiltration Rates for a Loessal Silt Loam Using Soil Properties

    Science.gov (United States)

    M. Dean Knighton

    1978-01-01

    Soil properties were related to infiltration rates as measured by single-ringsteady-head infiltometers. The properties showing strong simple correlations were identified. Regression models were developed to estimate infiltration rate from several soil properties. The best model gave fair agreement to measured rates at another location.

  15. Biomass and biofertilizer production by Sesbania cannabina in alkaline soil

    Energy Technology Data Exchange (ETDEWEB)

    Rao, D.L.N.; Gill, H.S. [Central Soil Salinity Research Inst., Haryana (India)

    1995-12-01

    Biomass shortages in developing countries require increased investigation into fast-growing, N-fixing, woody plant species. In field trials in north India, the potential of Sesbania cannabina for production of green leaf manure (biofertilizer) and firewood (woody biomass) was investigated. At 100 days after sowing (DAS), green matter was 21.5 and 9.4 Mg ha{sup -1} in the stem and the leaf. A seeding rate of 15 kg ha{sup -1} producing a population of 10{sup 5} plants per hectare was adequate. Biofertilizer potential was 124.7 N, 5.3 P, 80.7 K and 12.0 S (kg ha{sup -1}), respectively. Nodulation was profuse and effective and N fixed was nearly 122 kg ha{sup -1} at 100 DAS. At maturity, 200 DAS, woody biomass production was 19.2 Mg ha{sup -1} and growing Sesbania until this stage was no more demanding on soil nutrients than growing it for green-matter production. There was a considerable beneficial influence from growing Sesbania on soil C and N status. (Author)

  16. Nitrous oxide production from soils amended with biogas residues and cattle slurry.

    Science.gov (United States)

    Abubaker, J; Odlare, M; Pell, M

    2013-07-01

    The amount of residues generated from biogas production has increased dramatically due to the worldwide interest in renewable energy. A common way to handle the residues is to use them as fertilizers in crop production. Application of biogas residues to agricultural soils may be accompanied with environmental risks, such as increased NO emission. In 24-d laboratory experiments, NO dynamics and total production were studied in arable soils (sandy, clay, and organic) amended with one of two types of anaerobically digested biogas residues (BR-A and BR-B) generated from urban and agricultural waste and nondigested cattle slurry (CS) applied at rates corresponding to 70 kg NH-N ha. Total NO-N losses from the sandy soil were higher after amendment with BR-B (0.32 g NO-N m) than BR-A or CS (0.02 and 0.18 g NO-N m, respectively). In the clay soil, NO-N losses were very low for CS (0.02 g NO-N m) but higher for BR-A and BR-B (0.25 and 0.15 g NO-N m, respectively). In the organic soil, CS gave higher total NO-N losses (0.31 g NO-N m) than BR-A or BR-B (0.09 and 0.08 g NO-N m, respectively). Emission peaks differed considerably between soils, occurring on Day 1 in the organic soil and on Days 11 to 15 in the sand, whereas in the clay the peak varied markedly (Days 1, 6, and 13) depending on residue type. In all treatments, NH concentration decreased with time, and NO concentration increased. Potential ammonium oxidation and potential denitrification activity increased significantly in the amended sandy soil but not in the organic soil and only in the clay amended with CS. The results showed that fertilization with BR can increase NO emissions and that the size is dependent on the total N and organic C content of the slurry and on soil type. In conclusion, the two types of BR and the CS are not interchangeable regarding their effects on NO production in different soils, and, hence, matching fertilizer type to soil type could reduce NO emissions. For instance, it could be

  17. Effect of inorganic nitrogenous fertilizer on productivity of recently reclaimed saline sodic soils with and without biofertilizer.

    Science.gov (United States)

    Mehdi, S M; Sarfraz, M; Shabbir, G; Abbas, G

    2007-07-15

    Saline sodic soils after reclamation become infertile due to leaching of most of the nutrients along with salts from the rooting medium. Microbes can play a vital role in the productivity improvement of such soils. In this study a saline sodic field having EC, 6.5 dS m(-1), pH, 9.1 and gypsum requirement (GR) 3.5 tons acre(-1) was reclaimed by applying gypsum at the rate of 100% GR. Rice and wheat crops were transplanted/sown for three consecutive years. Inorganic nitrogenous fertilizer was used with and without biofertilizers i.e., Biopower (Azospirillum) for rice and diazotroph inoculums for wheat. Nitrogen was applied at the rate of 0, 75% of recommended dose (RD), RD, 125% of RD and 150% of RD. Recommended dose of P without K was applied to all the plots. Biopower significantly improved Paddy and straw yield of rice over inorganic nitrogenous fertilizer. In case of wheat diazotroph inoculum improved grain and straw yield significantly over inorganic nitrogenous fertilizer. Among N fertilizer rates, RD + 25% additional N fertilizer was found to be the best dose for rice and wheat production in recently reclaimed soils. Nitrogen concentration and its uptake by paddy, grain and straw were also increased by biopower and diazotroph inoculum over inorganic nitrogenous fertilizer. Among N fertilizer rates, RD + 25% additional N fertilizer was found to be the best dose for nitrogen concentration and its uptake by paddy, grain and straw. Total soil N, available P and extractable K were increased while salinity/sodicity parameters were decreased with the passage of time. The productivity of the soil was improved more by biofertilizers over inorganic N fertilizers.

  18. Plant species richness regulates soil respiration through changes in productivity.

    Science.gov (United States)

    Dias, André Tavares Corrêa; van Ruijven, Jasper; Berendse, Frank

    2010-07-01

    Soil respiration is an important pathway of the C cycle. However, it is still poorly understood how changes in plant community diversity can affect this ecosystem process. Here we used a long-term experiment consisting of a gradient of grassland plant species richness to test for effects of diversity on soil respiration. We hypothesized that plant diversity could affect soil respiration in two ways. On the one hand, more diverse plant communities have been shown to promote plant productivity, which could increase soil respiration. On the other hand, the nutrient concentration in the biomass produced has been shown to decrease with diversity, which could counteract the production-induced increase in soil respiration. Our results clearly show that soil respiration increased with species richness. Detailed analysis revealed that this effect was not due to differences in species composition. In general, soil respiration in mixtures was higher than would be expected from the monocultures. Path analysis revealed that species richness predominantly regulates soil respiration through changes in productivity. No evidence supporting the hypothesized negative effect of lower N concentration on soil respiration was found. We conclude that shifts in productivity are the main mechanism by which changes in plant diversity may affect soil respiration.

  19. Patterns of in-soil methane production and atmospheric emission among different land covers of a Lake Erie estuarine wetland

    Science.gov (United States)

    Rey Sanchez, C.; Morin, T. H.; Stefanik, K. C.; Angle, J.; Wrighton, K. C.; Bohrer, G.

    2017-12-01

    Wetland soils store a great amount of carbon, but also accumulate and emit methane (CH4), a powerful greenhouse gas. To better understand the vertical and horizontal spatial variability of CH4 emissions, we monitored production and fluxes of CH4 in Old Woman Creek, an estuarine wetland of Lake Erie, Ohio, during the growing seasons of 2015 and 2016. Our combined observation methods targeted three different scales: 1) the eddy covariance technique provided continuous high frequency observations integrated over a large spatial footprint; 2) monthly chamber measurements provided sparse point measurements of fluxes in four distinct land-cover types in the wetland: open water, emergent vegetation (Typha spp.), floating vegetation (Nelumbo spp.) and mud flats; and 3) in-situ porewater dialysis samplers, "peepers", provided vertical CH4 concentration data in the soil at the same locations and temporal time steps as the chambers. In addition, we studied gene transcripts to quantify methanogenesis activity along the vertical soil profile. Using integrated chamber and EC measurements, we found an average surface emission rate from Typha, the most abundant vegetated land cover, of 219.4 g CH4-C m-2 y-1, which was much higher than rates reported in similar emergent vegetation types in other wetlands. There was large spatial variation of flux rates, with mud flats having the highest rates of CH4 emission, followed by Nelumbo and Typha patches, and with open water having the lowest emissions. Within the soil column, we applied a numerical model to convert soil methane concentrations to emissions rates. We found that, contrary to current ideas of methane production, most methane was being produced in the well-oxygenated surface soils, probably in anoxic microsites within the oxic layer. Our metatranscriptomic data supported these findings, clearly showing nine times greater methanogenic activity in oxic surface soils relative to deeper anoxic soils. Combined, our results provide

  20. Soil Functional Zone Management: A Vehicle for Enhancing Production and Soil Ecosystem Services in Row-Crop Agroecosystems.

    Science.gov (United States)

    Williams, Alwyn; Kane, Daniel A; Ewing, Patrick M; Atwood, Lesley W; Jilling, Andrea; Li, Meng; Lou, Yi; Davis, Adam S; Grandy, A Stuart; Huerd, Sheri C; Hunter, Mitchell C; Koide, Roger T; Mortensen, David A; Smith, Richard G; Snapp, Sieglinde S; Spokas, Kurt A; Yannarell, Anthony C; Jordan, Nicholas R

    2016-01-01

    There is increasing global demand for food, bioenergy feedstocks and a wide variety of bio-based products. In response, agriculture has advanced production, but is increasingly depleting soil regulating and supporting ecosystem services. New production systems have emerged, such as no-tillage, that can enhance soil services but may limit yields. Moving forward, agricultural systems must reduce trade-offs between production and soil services. Soil functional zone management (SFZM) is a novel strategy for developing sustainable production systems that attempts to integrate the benefits of conventional, intensive agriculture, and no-tillage. SFZM creates distinct functional zones within crop row and inter-row spaces. By incorporating decimeter-scale spatial and temporal heterogeneity, SFZM attempts to foster greater soil biodiversity and integrate complementary soil processes at the sub-field level. Such integration maximizes soil services by creating zones of 'active turnover', optimized for crop growth and yield (provisioning services); and adjacent zones of 'soil building', that promote soil structure development, carbon storage, and moisture regulation (regulating and supporting services). These zones allow SFZM to secure existing agricultural productivity while avoiding or minimizing trade-offs with soil ecosystem services. Moreover, the specific properties of SFZM may enable sustainable increases in provisioning services via temporal intensification (expanding the portion of the year during which harvestable crops are grown). We present a conceptual model of 'virtuous cycles', illustrating how increases in crop yields within SFZM systems could create self-reinforcing feedback processes with desirable effects, including mitigation of trade-offs between yield maximization and soil ecosystem services. Through the creation of functionally distinct but interacting zones, SFZM may provide a vehicle for optimizing the delivery of multiple goods and services in

  1. Soil functional zone management: a vehicle for enhancing production and soil ecosystem services in row-crop agroecosystems

    Directory of Open Access Journals (Sweden)

    Alwyn eWilliams

    2016-02-01

    Full Text Available There is increasing global demand for food, bioenergy feedstocks and a wide variety of bio-based products. In response, agriculture has advanced production, but is increasingly depleting soil regulating and supporting ecosystem services. New production systems have emerged, such as no-tillage, that can enhance soil services but may limit yields. Moving forward, agricultural systems must reduce trade-offs between production and soil services. Soil functional zone management (SFZM is a novel strategy for developing sustainable production systems that attempts to integrate the benefits of conventional, intensive agriculture and no-tillage. SFZM creates distinct functional zones within crop row and inter-row spaces. By incorporating decimetre-scale spatial and temporal heterogeneity, SFZM attempts to foster greater soil biodiversity and integrate complementary soil processes at the sub-field level. Such integration maximizes soil services by creating zones of ‘active turnover’, optimized for crop growth and yield (provisioning services; and adjacent zones of ‘soil building’, that promote soil structure development, carbon storage and moisture regulation (regulating and supporting services. These zones allow SFZM to secure existing agricultural productivity while avoiding or minimizing trade-offs with soil ecosystem services. Moreover, the specific properties of SFZM may enable sustainable increases in provisioning services via temporal intensification (expanding the portion of the year during which harvestable crops are grown. We present a conceptual model of ‘virtuous cycles’, illustrating how increases in crop yields within SFZM systems could create self-reinforcing feedback processes with desirable effects, including mitigation of trade-offs between yield maximization and soil ecosystem services. Through the creation of functionally distinct but interacting zones, SFZM may provide a vehicle for optimizing the delivery of multiple

  2. Correlation Between Cone Penetration Rate And Measured Cone Penetration Parameters In Silty Soils

    DEFF Research Database (Denmark)

    Poulsen, Rikke; Nielsen, Benjaminn Nordahl; Ibsen, Lars Bo

    2013-01-01

    This paper shows, how a change in cone penetration rate affects the cone penetration measurements, hence the cone resistance, pore pressure, and sleeve friction in silty soil. The standard rate of penetration is 20 mm/s, and it is generally accepted that undrained penetration occurs in clay while...... drained penetration occurs in sand. When lowering the penetration rate, the soil pore water starts to dissipate and a change in the drainage condition is seen. In intermediate soils such as silty soils, the standard cone penetration rate may result in a drainage condition that could be undrained......, partially or fully drained. However, lowering the penetration rate in silty soils has a great significance because of the soil permeability, and only a small change in penetration rate will result in changed cone penetration measurements. In this paper, analyses will be done on data from 15 field cone...

  3. Soil Productive Lifespans: Rethinking Soil Sustainability for the 21st Century

    Science.gov (United States)

    Evans, Daniel

    2017-04-01

    The ability for humans to sustainably manage the natural resources on which they depend has been one of the existential challenges facing mankind since the dawn of civilisation. Given the demands from this century's unprecedented global population and the unremitting course of climatic change, that challenge has soared in intensity. Sustainability, in this context, refers to agricultural practices which meet the needs of the present without compromising the ability of future generations to meet their own needs. Ensuring sustainability is arguably of greatest importance when resources, such as soil, are non-renewable. However, there is as yet no tool to evaluate how sustainable conservation strategies are in the long-term. Up to now, many pedologists have assessed sustainability in binary terms, questioning whether management is sustainable or not. In truth, one can never determine whether a practice is ultimately sustainable because of the indefinite nature implied by "future generations". We suggest that a more useful assessment of sustainability for the 21st century should avoid binary questions and instead ask: how sustainable are soils? Indeed, how many future generations can soils provide for? Although the use of modelling is by no means a novelty for the discipline, there are very few holistic models that encompass the fluxes and dynamic relationships between both mass and quality concomitantly. We therefore propose a new conceptual framework - the Soil Productive Lifespan (SPL) - that employs empirically derived residence times of both soil mass and quality, together with pathways of environmental change, to forecast the length of time a soil profile can provide the critical functions. Although mass and quality are considered synergistically, the SPL model allows one to assess whether mass or quality alone presents the greatest limiting factor in the productive lifespans of soils. As a result, more targeted conservation strategies can be designed. Ultimately

  4. Soil management practices for sustainable crop production

    International Nuclear Information System (INIS)

    Abalos, E.B.

    2005-01-01

    In a sustainable system, the soil is viewed as a fragile and living medium that must be protected and nurtured to ensure its long-term productivity and stability. However, due to high demand for food brought about by high population as well as the decline in agricultural lands, the soil is being exploited beyond its limit thus, leading to poor or sick soils. Sound soil management practices in the Philippines is being reviewed. The technologies, including the advantages and disadvantages are hereby presented. This includes proper cropping systems, fertilizer program, soil erosion control and correcting soil acidity. Sound soil management practices which conserve organic matter for long-term sustainability includes addition of compost, maintaining soil cover, increasing aggregates stability, soil tilt and diversity of soil microbial life. A healthy soil is a key component to sustainability as a health soil produce healthy crop plants and have optimum vigor or less susceptible to pests. (author)

  5. Migration of radionuclides in the soil-crop-food product system and assessment of agricultural countermeasures

    International Nuclear Information System (INIS)

    Bogdevitch, I.; Ageyets, V.

    1996-01-01

    Studies on dynamics of redistribution of radionuclides through of profile of the different soils on uncultivated agricultural lands of Belarus during the 1986-1995 period show that vertical migration occurs with low rate. In arable soils the radionuclides are distributed in comparatively uniform way through the whole depth of the 25-30 cm cultivated layer. Investigations on migration of radionuclides with wind erosion on the drained series of wet sandy and peat soils and water erosion on sloping lands show that one should take into consideration the secondary contamination of soils while forecasting a possible accumulation of radionuclides in farm products

  6. Estimating cumulative soil accumulation rates with in situ-produced cosmogenic nuclide depth profiles

    International Nuclear Information System (INIS)

    Phillips, William M.

    2000-01-01

    A numerical model relating spatially averaged rates of cumulative soil accumulation and hillslope erosion to cosmogenic nuclide distribution in depth profiles is presented. Model predictions are compared with cosmogenic 21 Ne and AMS radiocarbon data from soils of the Pajarito Plateau, New Mexico. Rates of soil accumulation and hillslope erosion estimated by cosmogenic 21 Ne are significantly lower than rates indicated by radiocarbon and regional soil-geomorphic studies. The low apparent cosmogenic erosion rates are artifacts of high nuclide inheritance in cumulative soil parent material produced from erosion of old soils on hillslopes. In addition, 21 Ne profiles produced under conditions of rapid accumulation (>0.1 cm/a) are difficult to distinguish from bioturbated soil profiles. Modeling indicates that while 10 Be profiles will share this problem, both bioturbation and anomalous inheritance can be identified with measurement of in situ-produced 14 C

  7. Investigating CH4 production in an oxic plant-soil system -a new approach combining isotopic labelling (13C) and inhibitors

    Science.gov (United States)

    Lenhart, Katharina; Keppler, Frank

    2017-04-01

    Typically, aerated soil are net sinks of atmospheric methane (CH4), being highest in native ecosystems (pristine forests > managed forests > grasslands > crop fields). However, this does not exclude a simultaneous endogenic CH4 production in the plant-soil system, which cannot be detected simply via CH4 flux measurements. Methanogenic archaea producing CH4 under anoxic conditions were thought to be the only biotic source of CH4 in the soil. However, until recently a non-archaeal pathway of CH4 formation is known where CH4 is produced under oxic conditions in plants (Keppler et al. 2006) and fungi (Lenhart et al. 2012). Additionally, abiotic formation of CH4 from soil organic matter was reported (Jugold et al. 2012) and may be ubiquitous in terrestrial ecosystems. The major goal of this project was to determine soil endogenic CH4 sources and to estimate their contribution to the endogenic CH4 production. Especially the effect of plants and fungi on soil CH4 production was investigated. Therefore, a series of experiments was carried out on field fresh soil collected in a grassland and a forest ecosystem under controlled laboratory conditions. By combining selective inhibitors and 13C labelling, CH4 production rates of several CH4 sources were quantified. The major difficulty was to detect the comparatively small flux of CH4 production against the background of the high CH4 consumption rates due to methanotrophic bacteria. Therefore, we supplemented bare soil and soil with vegetation with selective inhibitors and 13C labelled substrates in a closed chamber system. In a first step, CH4 production was determined by the inhibition of CH4 oxidizing bacteria with Difluoromethane (DFM, 2ml l-1). In the following, a 13C labelled substrate (either CO2, Acetate, or Methionine -S-CH3 labelled) was added in combination with a specific inhibitor -either for archaeal methanogenesis (Bromoethanesulfonate), bacteria (Streptomycin), or fungi (Captan, Cycloheximide). Gas samples were

  8. Inoculum production of arbuscular mycorrhizal fungi native to soils under different forest covers

    Directory of Open Access Journals (Sweden)

    Renata Soares dos Santos

    Full Text Available ABSTRACT The low natural fertility of Brazilian soils requires the use of inoculants that facilitate the absorption of nutrients by plants. Arbuscular mycorrhizal fungi such as obligatory biotrophics of active roots perform this function, but access to this resource is limited by the difficulty in producing inoculants. The objective of this study was to investigate the production of AMF inoculants native of soils under different forest covers in Vitória da Conquista, BA, by means of spore quantification, colonization rate and species identification. For this purpose, soils were collected from sites under Mata Nativa (native forest and plantations of Madeira Nova (Pterogyne nitens and Eucalyptus, placed into separate 500 mL disposable cups with seeds of Brachiaria sp. and cultivated for five months. Spores were quantified and the AMF species identified in the control soil (without brachiaria and in the cups cultivated with brachiaria at each month. From the first month, the colonization rate of brachiaria roots was evaluated. The inoculants produced showed differences in the number of spores and species, in the AMF species identified, and in the root colonization rate as a function of the forest cover. Thus, considering the increase in the number of spores, species and colonization over time, the inoculant produced from the soil under native forest was more promising for utilization.

  9. Quantifying Cr(VI) Production and Export from Serpentine Soil of the California Coast Range.

    Science.gov (United States)

    McClain, Cynthia N; Fendorf, Scott; Webb, Samuel M; Maher, Kate

    2017-01-03

    Hexavalent chromium (Cr(VI)) is generated in serpentine soils and exported to surface and groundwaters at levels above health-based drinking water standards. Although Cr(VI) concentrations are elevated in serpentine soil pore water, few studies have reported field evidence documenting Cr(VI) production rates and fluxes that govern Cr(VI) transport from soil to water sources. We report Cr speciation (i) in four serpentine soil depth profiles derived from the California Coast Range serpentinite belt and (ii) in local surface waters. Within soils, we detected Cr(VI) in the same horizons where Cr(III)-minerals are colocated with biogenic Mn(III/IV)-oxides, suggesting Cr(VI) generation through oxidation by Mn-oxides. Water-extractable Cr(VI) concentrations increase with depth constituting a 7.8 to 12 kg/km 2 reservoir of Cr(VI) in soil. Here, Cr(VI) is produced at a rate of 0.3 to 4.8 kg Cr(VI)/km 2 /yr and subsequently flushed from soil during water infiltration, exporting 0.01 to 3.9 kg Cr(VI)/km 2 /yr at concentrations ranging from 25 to 172 μg/L. Although soil-derived Cr(VI) is leached from soil at concentrations exceeding 10 μg/L, due to reduction and dilution during transport to streams, Cr(VI) levels measured in local surface waters largely remain below California's drinking water limit.

  10. Comparison of soil erosion and deposition rates using radiocesium, RUSLE, and buried soils in dolines in East Tennessee

    International Nuclear Information System (INIS)

    Turnage, K.M.; Lee, S.Y.; Foss, J.E.; Kim, K.H.; Larsen, I.L.

    1997-01-01

    Three dolines (sinkholes), each representing different land uses (crop, grass, and forest) in a karst area in East Tennesse, were selected to determine soil erosional and depositional rates. Three methods were used to estimate the rates: fallout radiocesium ( 137 Cs) redistribution, buried surface soil horizons (Ab horizon), and the revised universal soil loss equation (RUSLE). When 137 Cs redistribution was examined, the average soil erosion rates were calculated to be 27 t ha -1 yr -1 at the cropland, 3 t ha -1 yr -1 at the grassland, and 2 t ha -1 yr -1 at the forest. By comparison, cropland erosion rate of 2.6 t ha -1 yr -1 , a grassland rate of 0.6 t ha -1 yr -1 , and a forest rate of 0.2 t ha -1 yr -1 were estimated by RUSLE. The 137 Cs method expressed higher rates than RUSLE because RUSLE tends to overestimate low erosion rates and does not account for deposition. The buried surface horizons method resulted in deposition rates that were 8 t ha -1 yr -1 (during 480 yr) at the cropland, 12 t ha -1 yr -1 (during 980 yr) at the grassland, and 4 t ha -1 yr -1 (during 101 yr) at the forest site. By examining 137 Cs redistribution, soil deposition rates were found to be 23 t ha -1 yr -1 at the cropland, 20 t ha -1 yr -1 at the grassland, and 16 t ha -1 yr -1 at the forest site. The variability in deposition rates was accounted for by temporal differences; 137 Cs expressed deposition during the last 38 yr, whereas Ab horizons represented deposition during hundreds of years. In most cases, land used affected both erosion and deposition rates - the highest rates of soil redistribution usually representing the cropland and the lowest, the forest. When this was not true, differences in the rates were attributed to differences in the size, shape, and closure of the dolines. (orig.)

  11. Comparison of diurnal dynamics in evaporation rate between bare soil and moss-crusted soil within a revegetated desert ecosystem of northwestern China

    Science.gov (United States)

    Zhang, Ya-Feng; Wang, Xin-Ping; Pan, Yan-Xia; Hu, Rui

    2016-02-01

    Effects of biological soil crusts (BSCs) on soil evaporation is quite controversial in literature, being either facilitative or inhibitive, and therein few studies have actually conducted direct evaporation measurements. Continuous field measurements of soil water evaporation were conducted on two microlysimeters, i.e., one with sand soil collected from bare sand dune area and the other with moss-crusted soil collected from an area that was revegetated in 1956, from field capacity to dry, at the southeastern edge of the Tengger Desert. We mainly aimed to quantify the diurnal variations of evaporation rate from two soils, and further comparatively discuss the effects of BSCs on soil evaporation after revegetation. Results showed that in clear days with high soil water content (Day 1 and 2), the diurnal variation of soil evaporation rate followed the typical convex upward parabolic curve, reaching its peak around mid-day. Diurnal evaporation rate and the accumulated evaporation amount of moss-crusted soil were lower (an average of 0.90 times) than that of sand soil in this stage. However, as soil water content decreased to a moderately low level (Day 3 and 4), the diurnal evaporation rate from moss-crusted soil was pronouncedly higher (an average of 3.91 times) than that of sand soil, prolonging the duration of this higher evaporation rate stage; it was slightly higher in the final stage (Day 5 and 6) when soil moisture was very low. We conclude that the effects of moss crusts on soil evaporation vary with different evaporation stages, which is closely related to soil water content, and the variation and transition of evaporation rate between bare soil and moss-crusted soil are expected to be predicted by soil water content.

  12. A spatial application of a vegetation productivity equation for neo-soil reconstruction

    International Nuclear Information System (INIS)

    Burley, J.B.

    1999-01-01

    Reclamation specialists are interested in the application of recently developed soil productivity equations for post-mining reclamation planning and design. This paper presents the application of one recently developed soil productivity equation to a surface coal mine site in Mercer County, North Dakota. Geographic information systems (GIS) technology (Map*Factory 1.1) was combined with a soil productivity equation developed by the author to generate a GIS script to calculate a site's pre-mining productivity per 10 meter grid cell and then summed to calculate the grand and the expected average soil productivity for the site, resulting in a pre-mining baseline numerical spatial scores. Several post-mining alternatives were evaluated to study various soil management strategies to restore post-mining soil productivity, including: an abandoned mine landscape treatment, a reconstructed topsoil treatment with graded gentile slopes, and a reconstructed topsoil treatment with soil improvements. The results indicated that the abandoned mine scenario was significantly different than the other three treatments (ple0.05), with the reconstructed topsoil treatment with soil amendments generating the greatest estimated productivity

  13. Sorption and degradation of wastewater-associated pharmaceuticals and personal care products in agricultural soils and sediment.

    Science.gov (United States)

    Zhang, Ting; Wu, Bo; Sun, Na; Ye, Yong; Chen, Huaixia

    2013-01-01

    Pharmaceuticals and personal care products (PPCPs) have drawn popular concerns recently as an emerging class of aquatic contaminants. In this study, adsorption and degradation of four selected PPCPs, metronidazole, tinidazole, caffeine and chloramphenicol, have been investigated in the laboratory using two agricultural soils in China and sediment from Changjiang River. Adsorption tests using a batch equilibrium method demonstrated that adsorption of all tested chemicals in soils could be well described with Freundlich equation, and their adsorption affinity on soil followed the order of chloramphenicol > caffeine > tinidazole > metronidazole. Generally, higher Kf value was associated with soils which had higher organic matter contents (except for caffeine acid in this study). Degradation of selected PPCPs in soils generally followed first-order exponential decay kinetics, and half-lives ranging from 0.97 to 10.21 d. Sterilization generally decreased the degradation rates, indicating that microbial activity played a significant role in the degradation in soils. The degradation rate constant decreased with increasing initial chemical concentrations in soil, implying that the microbial activity was inhibited with high chemical loading levels.

  14. Evaporation of petroleum products from contaminated soils

    International Nuclear Information System (INIS)

    Kang, S.H.

    1996-01-01

    Bioremediation can remove petroleum products from soil that has been contaminated by leaking underground storage tanks, but abiotic processes such as evaporation can contribute significantly to the overall removal process. The mathematical model described in this paper was developed to predict the evaporation rate of volatile liquids from petroleum-contaminated sand. The model is based on simple concepts relating to molecular diffusion embodied in the theory underlying the estimation of binary diffusivities using measurements made with an Arnold diffusion cell. The model in its simplified form indicates that the rate of evaporation for a particular volatile liquid is proportional to the square root of the product of diffusivity and partial pressure divided by the molecular weight of the liquid. This in part explains why evaporative losses from sand are so much higher for gasoline than for diesel fuel. The model also shows that the time for evaporation is directly proportional to the square of the depth dried out and inversely proportional to the vapor pressure of the volatile liquid. The model was tested using gravimetric measurements of the evaporation of n-heptane, unleaded gasoline, and diesel fuel from sand under laboratory conditions

  15. Long-term carbon exclusion alters soil microbial function but not community structure across forests of contrasting productivity

    Science.gov (United States)

    Hart, S. C.; Dove, N. C.; Stark, J.

    2017-12-01

    While it is well-documented that distinct heterotrophic microbial communities emerge under different conditions of carbon (C) availability, the response of soil microbial communities and their function to long-term conditions of C exclusion in situ has yet to be investigated. We evaluated the role of C in controlling soil microbial communities and function by experimentally excluding plant C inputs for nine years at four forest sites along a productivity gradient in Oregon, USA. Carbon exclusion treatments were implemented by root trenching to a depth of 30 cm using 25-cm diameter steel pipe, and minimizing aboveground inputs as plant litter by covering the pipe with a 1-mm mesh screen. After nine years, we measured rates of gross and net nitrogen (N) transformations and microbial respiration in situ in the upper 15-cm of mineral soil in both C excluded plots and undisturbed control soils. We measured the soil total C and N concentration and potential extracellular enzyme activities. We used phospholipid fatty acid (PLFA) analysis to determine potential changes in the microbial community structure. Nine years of C exclusion reduced soil total C by about 20%, except at the highest productivity site where no statistically significant change was observed. Although PLFA community structure and microbial C were unchanged, microbial respiration was reduced by 15-45% at all sites. Similarly, specific extracellular enzyme activities for all enzymes increased at these sites with C exclusion, suggesting that the microbial communities were substrate-limited. Although gross N mineralization decreased under C exclusion, decreases in gross N immobilization were greater, resulting in increased net N mineralization rates in all but the lowest productivity site. Furthermore, C exclusion only increased net nitrification in the highest productivity site. Although these field-based results are largely consistent with previous laboratory studies indicating a strong coupling between C

  16. Quantification Of Erosion Rates Of Agriculturally Used Soils By Artificial

    Science.gov (United States)

    Jha, Abhinand

    2010-05-01

    0.0.1 1. Introduction to soil erosion measurement by radionuclides Soil erosion by water, wind and tillage affects both agriculture and the natural environment. Studying this phenomenon would be one of the advancements in science. Soil erosion occurs worldwide and since the last two decades it has been a main topic of discussion all over the world. The use of environmental radionuclides such as 90Sr, 137Cs to study medium term soil erosion (40 yrs) started in the early 1990's. Using these new techniques better knowledge about erosion can be gained and this knowledge can be implemented for erosion risk management. The erosion and sedimentation study by using man-made and natural radioisotopes is a key technique, which has developed over the past 30 years. Fallout 137Cs and Cosmogenic 7Be are radionuclides that have been used to provide independent measurements of soil-erosion and sediment-deposition rates and patterns [1] [2] [3] [4]. Erosion measurements using radionuclides 137Cs, 7Be Caesium-137 from atmospheric nuclear-weapons tests in the 1950s and 1960s (Fig.1) is a unique tracer of erosion and sedimentation, since there are no natural sources of 137Cs. Unique events such as the Chernobyl accident in April 1986 caused regional dispersal of 137Cs that affects the total global deposition budget. This yearly pattern of fallout can be used to develop a chronology of deposition horizons in lakes, reservoirs, and floodplains. 137Cs can be easily measured by gamma spectroscopy. Using 137Cs is a fast and cheap method to study erosion-deposition processes compared to the traditional methods like silt bags. PIC Figure 1: Global 137Cs fallout (Modified from SAAS Bulletin 353, Part E, DDR, 1986) When 137Cs, 7Be reach the soil surface by wet and dry deposition, they are quickly and strongly adsorbed by ion exchange and are essentially non exchangeable in most environments. Each radionuclide is distributed differently in the soil because of differences in half-lives (30 yrs

  17. Crop and soil specific N and P efficiency and productivity in Finland

    Directory of Open Access Journals (Sweden)

    S. BÄCKMAN

    2008-12-01

    Full Text Available This paper estimates a stochastic production frontier based on experimental data of cereals production in Finland over the period 1977-1994. The estimates of the production frontier are used to analyze nitrogen and phosphorous productivity and efficiency differences between soils and crops. For this input specific efficiencies are calculated. The results can be used to recognize relations between fertilizer management and soil types as well as to learn where certain soil types and crop combinations require special attention to fertilization strategy. The combination of inputs as designed by the experiment shows significant inefficiencies for both N and P. The measures of mineral productivity and efficiency indicate that clay is the most mineral efficient and productive soil while silt and organic soils are the least efficient and productive soils. Furthermore, a positive correlation is found between mineral productivity and efficiency. The results indicate that substantial technical efficiency differences between different experiments prevail.;

  18. 30 CFR 823.15 - Revegetation and restoration of soil productivity.

    Science.gov (United States)

    2010-07-01

    ... productivity. 823.15 Section 823.15 Mineral Resources OFFICE OF SURFACE MINING RECLAMATION AND ENFORCEMENT... STANDARDS-OPERATIONS ON PRIME FARMLAND § 823.15 Revegetation and restoration of soil productivity. (a... productivity shall be restored in accordance with the following provisions: (1) Measurement of soil...

  19. Primary productivity as a control over soil microbial diversity along environmental gradients in a polar desert ecosystem

    Directory of Open Access Journals (Sweden)

    Kevin M. Geyer

    2017-07-01

    Full Text Available Primary production is the fundamental source of energy to foodwebs and ecosystems, and is thus an important constraint on soil communities. This coupling is particularly evident in polar terrestrial ecosystems where biological diversity and activity is tightly constrained by edaphic gradients of productivity (e.g., soil moisture, organic carbon availability and geochemical severity (e.g., pH, electrical conductivity. In the McMurdo Dry Valleys of Antarctica, environmental gradients determine numerous properties of soil communities and yet relatively few estimates of gross or net primary productivity (GPP, NPP exist for this region. Here we describe a survey utilizing pulse amplitude modulation (PAM fluorometry to estimate rates of GPP across a broad environmental gradient along with belowground microbial diversity and decomposition. PAM estimates of GPP ranged from an average of 0.27 μmol O2/m2/s in the most arid soils to an average of 6.97 μmol O2/m2/s in the most productive soils, the latter equivalent to 217 g C/m2/y in annual NPP assuming a 60 day growing season. A diversity index of four carbon-acquiring enzyme activities also increased with soil productivity, suggesting that the diversity of organic substrates in mesic environments may be an additional driver of microbial diversity. Overall, soil productivity was a stronger predictor of microbial diversity and enzymatic activity than any estimate of geochemical severity. These results highlight the fundamental role of environmental gradients to control community diversity and the dynamics of ecosystem-scale carbon pools in arid systems.

  20. Irradiated Sewage Sludge for Production of Fennel Plants in Sandy Soil

    International Nuclear Information System (INIS)

    El-Motaium, R. A.; Abo El-Seoud, M. A.

    2004-01-01

    Irradiated sewage sludge (SS) has proved to be a useful organic fertilizer particularly for sandy soil. The objective of this study is to compare the response of fennel (Foeniculum vulgare L.) plants growing in sandy soil to different fertilizer regimes, organic vs. mineral. In a field experiment four levels (20, 40, 60, 80 t/ha) of irradiated and non-irradiated sewage sludge were incorporated into sandy soil, in addition to the control treatment (mineral fertilizer). Samples analysis included the biomass production at the vegetative and flowering stages, chlorophyll content, total and reducing sugars and heavy metals content of the shoots. The data indicate that the biomass production has dramatically increased as the sludge application rate increased in both irradiated and non-irradiated plots. However, the increase was significantly higher under all irradiated treatments than the corresponding rates of non-irradiated treatments at both the vegetative and flowering stages. Also, the biomass production at all levels of application was higher than the control, receiving mineral fertilizer. At the vegetative stage, the biomass values ranged from 3.1 g/plant for the control to 10.2 and 34.1 g/plant at 80 t/ha for non-irradiated and irradiated sewage sludge, respectively. Whereas, at the flowering stage the values ranged from 9.8 g/plant for the control to 23.9 and 65.1 g/plant at 80 t/ha for non-irradiated and irradiated sewage sludge, respectively. Total sugars, reducing sugar, non-reducing sugar, and chlorophyll content has increased as the sludge application rate increased. At 80t/ha application rate of irradiated sludge, the reducing sugars content was 29.39 mg/g DW at the vegetative stage and 37.85 mg/g DW at the flowering stage. Reducing sugars recorded lower values in the control plants, 14.54 mg/g DW at the vegetative stage and 18.78 mg/g DW at the flowering stage. Heavy metals (Zn, Fe, Pb, Cd) of the shoots was also determined. Sewage sludge was a good

  1. Legacy effects of anaerobic soil disinfestation on soil bacterial community composition and production of pathogen-suppressing volatiles

    Directory of Open Access Journals (Sweden)

    Maaike evan Agtmaal

    2015-07-01

    Full Text Available There is increasing evidence that microbial volatiles (VOCs play an important role in natural suppression of soil-borne diseases, but little is known on the factors that influence production of suppressing VOCs. In the current study we examined whether a stress-induced change in soil microbial community composition would affect the production by soils of VOCs suppressing the plant-pathogenic oomycete Pythium. Using pyrosequencing of 16S ribosomal gene fragments we compared the composition of bacterial communities in sandy soils that had been exposed to anaerobic disinfestation (AD, a treatment used to kill harmful soil organisms, with the composition in untreated soils. Three months after the AD treatment had been finished, there was still a clear legacy effect of the former anaerobic stress on bacterial community composition with a strong increase in relative abundance of the phylum Bacteroidetes and a significant decrease of the phyla Acidobacteria, Planctomycetes, Nitrospirae, Chloroflexi and Chlorobi. This change in bacterial community composition coincided with loss of production of Pythium suppressing soil volatiles (VOCs and of suppression of Pythium impacts on Hyacinth root development. One year later, the composition of the bacterial community in the AD soils was reflecting that of the untreated soils. In addition, both production of Pythium-suppressing VOCs and suppression of Pythium in Hyacinth bioassays had returned to the levels of the untreated soil. GC/MS analysis identified several VOCs, among which compounds known to be antifungal, that were produced in the untreated soils but not in the AD soils. These compounds were again produced 15 months after the AD treatment. Our data indicate that soils exposed to a drastic stress can temporarily lose pathogen suppressive characteristics and that both loss and return of these suppressive characteristics coincides with shifts in the soil bacterial community composition. Our data are

  2. Influence of the organic matter and soil water deficit on the castor bean absolute growth rate

    Energy Technology Data Exchange (ETDEWEB)

    Lacerda, Rogerio Dantas de; Guerra, Hugo O. Carvallo; Chaves, Lucia Helena G. [Universidade Federal de Campina Grande (UAEAg/UFCG), PB (Brazil). Unidade Academica de Engenharia Agricola; Araujo, Ester Luiz de; Nascimento, Elka Costa Santos; Barros Junior, Genival [Universidade Federal de Campina Grande (UFCG), PB (Brazil)

    2008-07-01

    Even when under low precipitations conditions, the castor bean production decrease, it constitutes a very good alternative. It has an elevated economical importance, because from the plant it is used their leaves, stem and seeds. From the stem it is obtained cellulose for the paper industry, from the leaves textile products and from the seeds oil and tort. The oil is the only glycerin soluble in alcohol and the base for several industrial products such as the biodiesel. The objective of the present work was to study the effect of different soil water and soil organic matter on the castor bean, BRS 188 cultivar rate growth. The experiment was conducted from April to August 2006 under greenhouse conditions using a randomized block 2x4 factorial design with two soil organic mater content (5.0 g.kg{sup -1} e 25.0 g.kg{sup -1}), four levels of available water (100, 90, 80 e 70% ) and three replicates. For this, 24 plastic containers, 75 kg capacity, were used on which was grown one plant 120 days after the seedling. At regular intervals the plant height was measured and the results analyzed statistically. For the qualitative treatments (with and without organic matter) the treatment means were compared through the Tukey test. For the quantitative ones (water levels) regressions were used. It was observed that both, organic matter and available water for plants proportionated benefit effects to the growth rate of the plant. (author)

  3. Microbial community structure and soil pH correspond to methane production in Arctic Alaska soils.

    Science.gov (United States)

    Wagner, Robert; Zona, Donatella; Oechel, Walter; Lipson, David

    2017-08-01

    While there is no doubt that biogenic methane production in the Arctic is an important aspect of global methane emissions, the relative roles of microbial community characteristics and soil environmental conditions in controlling Arctic methane emissions remains uncertain. Here, relevant methane-cycling microbial groups were investigated at two remote Arctic sites with respect to soil potential methane production (PMP). Percent abundances of methanogens and iron-reducing bacteria correlated with increased PMP, while methanotrophs correlated with decreased PMP. Interestingly, α-diversity of the methanogens was positively correlated with PMP, while β-diversity was unrelated to PMP. The β-diversity of the entire microbial community, however, was related to PMP. Shannon diversity was a better correlate of PMP than Simpson diversity across analyses, while rarefied species richness was a weak correlate of PMP. These results demonstrate the following: first, soil pH and microbial community structure both probably control methane production in Arctic soils. Second, there may be high functional redundancy in the methanogens with regard to methane production. Third, iron-reducing bacteria co-occur with methanogens in Arctic soils, and iron-reduction-mediated effects on methanogenesis may be controlled by α- and β-diversity. And finally, species evenness and rare species abundances may be driving relationships between microbial groups, influencing Arctic methane production. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  4. The rates of carbon cycling in several soils from AMS14C measurements of fractionated soil organic matter

    International Nuclear Information System (INIS)

    Trumbore, S.E.; Bonani, G.; Wolfli, W.

    1990-01-01

    14 C mean residence times (MRT) of fractionated organic matter are reported for three pre-bomb soil profiles. Comparisons of organic matter extracted with acid and base showed that the longest MRTs were associated with the non-acid-hydrolysable fraction. The MRT of organic matter in a soil layer represents a combination of the rates of several processes, including decay to CO 2 and transport out of the layer. In some instances (notably in the A horizon of the Podzol soil studied in this paper), the MRT is dominated by the rate of transport, rather than the rate of decay. Thus it is important to use the distribution and balance of carbon in the soil profile to assess the meaning of the MRT with respect to influencing atmospheric CO 2

  5. Physical soil properties and slope treatments effects on hydraulic excavator productivity for forest road construction.

    Science.gov (United States)

    Parsakho, Aidin; Hosseini, Seyed Ataollah; Jalilvand, Hamid; Lotfalian, Majid

    2008-06-01

    Effects of moisture, porosity and soil bulk density properties, grubbing time and terrain side slopes on pc 220 komatsu hydraulic excavator productivity were investigated in Miana forests road construction project which located in the northern forest of Iran. Soil moisture and porosity determined by samples were taken from undisturbed soil. The elements of daily works were measured with a digital stop watch and video camera in 14 observations (days). The road length and cross section profiles after each 20 m were selected to estimate earthworks volume. Results showed that the mean production rates for the pc 220 komatsu excavators were 60.13 m3 h(-1) and earthwork 14.76 m h(-1) when the mean depth of excavation or cutting was 4.27 m3 m(-1), respectively. There was no significant effects (p = 0.5288) from the slope classes' treatments on productivity, whereas grubbing time, soil moisture, bulk density and porosity had significantly affected on excavator earthworks volume (p < 0.0001). Clear difference was showed between the earthwork length by slope classes (p = 0.0060). Grubbing time (p = 0.2180), soil moisture (p = 0.1622), bulk density (p = 0.2490) and porosity (p = 0.2159) had no significant effect on the excavator earthworks length.

  6. Effect of Soil pH Increase by Biochar on NO, N2O and N2 Production during Denitrification in Acid Soils.

    Directory of Open Access Journals (Sweden)

    Alfred Obia

    Full Text Available Biochar (BC application to soil suppresses emission of nitrous- (N2O and nitric oxide (NO, but the mechanisms are unclear. One of the most prominent features of BC is its alkalizing effect in soils, which may affect denitrification and its product stoichiometry directly or indirectly. We conducted laboratory experiments with anoxic slurries of acid Acrisols from Indonesia and Zambia and two contrasting BCs produced locally from rice husk and cacao shell. Dose-dependent responses of denitrification and gaseous products (NO, N2O and N2 were assessed by high-resolution gas kinetics and related to the alkalizing effect of the BCs. To delineate the pH effect from other BC effects, we removed part of the alkalinity by leaching the BCs with water and acid prior to incubation. Uncharred cacao shell and sodium hydroxide (NaOH were also included in the study. The untreated BCs suppressed N2O and NO and increased N2 production during denitrification, irrespective of the effect on denitrification rate. The extent of N2O and NO suppression was dose-dependent and increased with the alkalizing effect of the two BC types, which was strongest for cacao shell BC. Acid leaching of BC, which decreased its alkalizing effect, reduced or eliminated the ability of BC to suppress N2O and NO net production. Just like untreated BCs, NaOH reduced net production of N2O and NO while increasing that of N2. This confirms the importance of altered soil pH for denitrification product stoichiometry. Addition of uncharred cacao shell stimulated denitrification strongly due to availability of labile carbon but only minor effects on the product stoichiometry of denitrification were found, in accordance with its modest effect on soil pH. Our study indicates that stimulation of denitrification was mainly due to increases in labile carbon whereas change in product stoichiometry was mainly due to a change in soil pH.

  7. Improvements of soil quality for increased food production in Norway

    Science.gov (United States)

    Øygarden, Lillian; Klakegg, Ove; Børresen, Trond; Krogstad, Tore; Kjersti Uhlen, Anne

    2016-04-01

    Since the 1990ties, agricultural land in use in Norway has diminished and yields per hectare for cereals and forages have stagnated. An expert panel appointed to advice on how to increase Norwegian grain production emphasizes low profitability and poor soil quality as limiting factors. A White Paper from the Norwegian Government, Report No.9 (2011-2012), stated that the main goal for the agricultural sector is to increase food production proportional to the expected increase in population (20 % by 2030) in order to maintain self-sufficiency at the present level. This is the background for the interdisciplinary project AGROPRO "Agronomy for increased food production - Challenges and solutions" (2013 - 2017)" financed by the Norwegian research council. A mail goal is seeking possibilities for improvements in agronomic practices for increased and sustainable food production and to identify drivers and challenges for their implementation. Are the key to higher yields hidden in the soil? The paper present an overview of the research activities in the project and some results of the improvements of soil quality to minimize yield gap in cereal and forage production. Detailed new soil maps provide soil information on field scale of soil quality and the suitability for growing different crops like cereal production or vegetables. The detailed soil information is also beeing used for development and adaptation of the planning tool «Terranimo» to reduce risk of soil compaction.The farmer get available soil information for each field, provide information about the maschinery in use- tractors and equipment, tyres, pressure. The decision tool evaluate when the soil is suitable for tillage, calculate the risk of compaction for dry, moist and wet soil. New research data for compaction on Norwegian clay and silt soil are included. Climate change with wetter conditions gives challenges for growing cereals. The project is testing genetic variation in cereals for tolerance to water

  8. Application of different lime rates and phosphorus on soil physico ...

    African Journals Online (AJOL)

    The treatments were factorial combination of five rates of phosphorus (0, 11.5, 23, 46, 57.5 kg P2O5) and four rates of lime (CaCO3) (0, 2.25, 3 and 3.75 tons ha-1) in randomized complete block design and replicated three times. The pre soil analysis indicated that the soil of experimental area was acidic (pH = 5.31) and low ...

  9. Production of Microbial Protease from Selected Soil Fungal Isolates ...

    African Journals Online (AJOL)

    Production of Microbial Protease from Selected Soil Fungal Isolates. ... Nigerian Journal of Biotechnology ... and 500C. The optimal pH on the enzyme production was observed to be between pH 3.5 and 5.5 for the organisms. Keywords: Soil microorganism, fungal isolate, incubation period, microbial enzyme. Nig J. Biotech.

  10. Long-term manure applications improve soil productivity and sustain high crop yield for acidic red soils

    Science.gov (United States)

    Intensive use of chemical nitrogen (N) fertilizers has resulted in severely reduced productivity of red soils (Ferralic Cambisol) due to accelerated acidification. Manure has been shown to be effective in improving soil productivity by preventing or reversing the acidification process, but little in...

  11. Capacity of biochar application to maintain energy crop productivity: soil chemistry, sorghum growth, and runoff water quality effects.

    Science.gov (United States)

    Schnell, Ronnie W; Vietor, Donald M; Provin, Tony L; Munster, Clyde L; Capareda, Sergio

    2012-01-01

    Pyrolysis of crop biomass generates a by-product, biochar, which can be recycled to sustain nutrient and organic C concentrations in biomass production fields. We evaluated effects of biochar rate and application method on soil properties, nutrient balance, biomass production, and water quality. Three replications of eight sorghum [ (L.) Moench] treatments were installed in box lysimeters under greenhouse conditions. Treatments comprised increasing rates (0, 1.5, and 3.0 Mg ha) of topdressed or incorporated biochar supplemented with N fertilizer or N, P, and K fertilizer. Simulated rain was applied at 21 and 34 d after planting, and mass runoff loss of N, P, and K was measured. A mass balance of total N, P, and K was performed after 45 d. Returning 3.0 Mg ha of biochar did not affect sorghum biomass, soil total, or Mehlich-3-extractable nutrients compared to control soil. Yet, biochar contributed to increased concentration of dissolved reactive phosphorus (DRP) and mass loss of total phosphorus (TP) in simulated runoff, especially if topdressed. It was estimated that up to 20% of TP in topdressed biochar was lost in surface runoff after two rain events. Poor recovery of nutrients during pyrolysis and excessive runoff loss of nutrients for topdressed biochar, especially K, resulted in negative nutrient balances. Efforts to conserve nutrients during pyrolysis and incorporation of biochar at rates derived from annual biomass yields will be necessary for biochar use in sustainable energy crop production. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  12. Illinois reclaimed soil productivity: Restoration techniques

    International Nuclear Information System (INIS)

    Smout, G.

    1998-01-01

    Consolidation Coal Co. (Consol) has nearly 8,000 acres of high capability and prime farmland reclamation responsibility in Illinois. It has been involved in research in the area of restored soil productivity since 1976 with the University of Illinois and Southern Illinois University, Carbondale. Consol maintains an intensive program to demonstrate and test deep tillage equipment. The research and in-house demonstrations identified soil physical strength (compaction) as the main limiting factor to restoring a soil's productive capacity. There are two primary ways to address this issue, prevention and amelioration. The former was not an option for Consol because many acres were already reclaimed and the company had a major scraper fleet. Along with other operators in Illinois, Consol started an aggressive search for equipment and techniques that could loosen compacted soils. In 1987 Consol was the first to use the D.M.I.-Super Tiger deep soil plow, originally developed and manufactured by D.M.I., Inc. of Goodfield, Illinois. This plow is composed of a single parabolic, static shank with a 44-inch wide sweep weighing 1,200 pounds. It is capable of plowing 48 inches deep while leaving the top soil in place. A Caterpillar D9L tractor with 460 horsepower is used to pull the plow. In 1990 the decision was made to commit to this equipment as the best technology currently available. In 1994 Consol received a patent waiver from D.M.I. to build its own plow. The Consol built plow has been in use since the summer of 1995. To date, Consol has plowed over 3,900 acres with a D.M.I. plow

  13. Soil ingestion rates for children under 3 years old in Taiwan

    Science.gov (United States)

    Soil and dust ingestion rates by children are among the most critical exposure factors in determining risks to children from exposures to environmental contaminants in soil and dust. This is the first published soil ingestion study for children in Taiwan using tracer element meth...

  14. Phosphorus vertical migration in aquic brown soil and light chernozem under different phosphorous application rate: a soil column leaching experiment.

    Science.gov (United States)

    Zhao, Muqiu; Chen, Xin; Shi, Yi; Zhou, Quanlai; Lu, Caiyan

    2009-01-01

    A soil column leaching experiment was conducted to study the vertical migration of phosphorus in aquic brown soil and light chernozem under different phosphorus fertilization rates. The results showed that total dissolved phosphorus concentration in the leachates from the two soils was nearly the same, but dissolved inorganic phosphorus concentration was obviously different. In all fertilization treatments, aquic brown soil had a higher content of phosphorus in calcium chloride extracts compared with light chernozem. But Olsen phosphorus content was higher at the soil depth beneath 0-20 cm, and increased with increasing phosphorus application rate.

  15. The Effect of Altered Soil Moisture on Hybridization Rate in a Crop-Wild System (Raphanus spp..

    Directory of Open Access Journals (Sweden)

    Lesley G Campbell

    Full Text Available Since plant mating choices are flexible and responsive to the environment, rates of spontaneous hybridization may vary across ecological clines. Developing a robust and predictive framework for rates of plant gene flow requires assessing the role of environmental sensitivity on plant reproductive traits, relative abundance, and pollen vectors. Therefore, across a soil moisture gradient, we quantified pollinator movement, life-history trait variation, and unidirectional hybridization rates from crop (Raphanus sativus to wild (Raphanus raphanistrum radish populations. Both radish species were grown together in relatively dry (no rain, relatively wet (double rain, or control soil moisture conditions in Ohio, USA. We measured wild and crop radish life-history, phenology and pollinator visitation patterns. To quantify hybridization rates from crop-to-wild species, we used a simply inherited morphological marker to detect F1 hybrid progeny. Although crop-to-wild hybridization did not respond to watering treatments, the abundance of hybrid offspring was higher in fruits produced late in the period of phenological overlap, when both species had roughly equal numbers of open flowers. Therefore, the timing of fruit production and its relationship to flowering overlap may be more important to hybrid zone formation in Raphanus spp. than soil moisture or pollen vector movements.

  16. Landscape Influences on Potential Soil Respiration Rates in a Forested Watershed of Southeastern Kentucky

    Science.gov (United States)

    Amanda C. Abnee; James A. Thompson; Randall K. Kolka; Elisa M. D' Angelo; Mark S. Coyne

    2004-01-01

    Soil respiration measurements conducted in the laboratory have been shown to be related to temperature and moisture, with maximum rates at soil temperatures between 25 and 40°C and soil moisture between -0.01 and -0.10 MPa. A preliminary study using forest soils from eastern Kentucky supported the previous research with soil respiration rates greater at 25°C than at 15...

  17. Predicting the temporal relationship between soil cesium-137 and erosion rate

    International Nuclear Information System (INIS)

    Kachanoski, R.G.; De Jong, E.

    1984-01-01

    A model was developed that predicts the amount of 137 Cs remaining in soil as a function of time and erosion rate. The model accounts for atmospheric deposition, radioactive decay, tillage dilution, and erosion transport of 137 Cs, as well as seasonal differences in 137 Cs deposition and erosion rates. The model was used to estimate minimum resolution of erosion estimates based on detection limits and accuracy of 137 Cs measurement by gamma spectroscopy, as a function of time and erosion rate. The analysis showed that under Saskatchewan conditions, changes in 137 Cs at a given site can be used to estimate erosion rates between 0.5 and 10 kg m -2 yr -1 with reasonable precision, provided the sampling interval is at least 15 yr. The relationship of fraction of 137 Cs lost vs. erosion as predicted by the model was compared with other methods being used. The model was used to estimate erosion from selected Saskatchewan soils where 137 Cs levels were measured in 1966 and again in 1981. Erosion rates calculated with the model varied from 1 kg m -2 yr -1 for a sandy loam soil in continuous forage to 19 kg m -2 yr -1 for a similar soil in a crop-fallow rotation. Erosion estimates using the model were higher than those calculated by assuming that soil loss was directly proportional to 137 Cs loss, especially when 137 Cs loss was high

  18. Soil moisture variability across different scales in an Indian watershed for satellite soil moisture product validation

    KAUST Repository

    Singh, Gurjeet; Panda, Rabindra K.; Mohanty, Binayak P.; Jana, Raghavendra Belur

    2016-01-01

    Strategic ground-based sampling of soil moisture across multiple scales is necessary to validate remotely sensed quantities such as NASA’s Soil Moisture Active Passive (SMAP) product. In the present study, in-situ soil moisture data were collected

  19. Increasing Soil Organic Matter Enhances Inherent Soil Productivity while Offsetting Fertilization Effect under a Rice Cropping System

    Directory of Open Access Journals (Sweden)

    Ya-Nan Zhao

    2016-09-01

    Full Text Available Understanding the role of soil organic matter (SOM in soil quality and subsequent crop yield and input requirements is useful for agricultural sustainability. SOM is widely considered to affect a wide range of soil properties, however, great uncertainty still remains in identifying the relationships between SOM and crop yield due to the difficulty in separating the effect of SOM from other yield-limiting factors. Based on 543 on-farm experiments, where paired treatments with and without NPK fertilizer were conducted during 2005–2009, we quantified the inherent soil productivity, fertilization effect, and their contribution to rice yield and further evaluated their relationships with SOM contents under a rice cropping system in the Sichuan Basin of China. The inherent soil productivity assessed by rice grain yield under no fertilization (Y-CK was 5.8 t/ha, on average, and contributed 70% to the 8.3 t/ha of rice yield under NPK fertilization (Y-NPK while the other 30% was from the fertilization effect (FE. No significant correlation between SOM content and Y-NPK was observed, however, SOM content positively related to Y-CK and its contribution to Y-NPK but negatively to FE and its contribution to Y-NPK, indicating an increased soil contribution but a decreased fertilizer contribution to rice yield with increasing SOM. There were significantly positive relationships between SOM and soil available N, P, and K, indicating the potential contribution of SOM to inherent soil productivity by supplying nutrients from mineralization. As a result, approaches for SOM accumulation are practical to improve the inherent soil productivity and thereafter maintain a high crop productivity with less dependence on chemical fertilizers, while fertilization recommendations need to be adjusted with the temporal and spatial SOM variation.

  20. Soil metagenomics and tropical soil productivity

    OpenAIRE

    Garrett, Karen A.

    2009-01-01

    This presentation summarizes research in the soil metagenomics cross cutting research activity. Soil metagenomics studies soil microbial communities as contributors to soil health.C CCRA-4 (Soil Metagenomics)

  1. Methanethiol-dependent dimethylsulfide production in soil environments.

    Science.gov (United States)

    Carrión, Ornella; Pratscher, Jennifer; Curson, Andrew R J; Williams, Beth T; Rostant, Wayne G; Murrell, J Colin; Todd, Jonathan D

    2017-10-01

    Dimethylsulfide (DMS) is an environmentally important trace gas with roles in sulfur cycling, signalling to higher organisms and in atmospheric chemistry. DMS is believed to be predominantly produced in marine environments via microbial degradation of the osmolyte dimethylsulfoniopropionate (DMSP). However, significant amounts of DMS are also generated from terrestrial environments, for example, peat bogs can emit ~6 μmol DMS m -2 per day, likely via the methylation of methanethiol (MeSH). A methyltransferase enzyme termed 'MddA', which catalyses the methylation of MeSH, generating DMS, in a wide range of bacteria and some cyanobacteria, may mediate this process, as the mddA gene is abundant in terrestrial metagenomes. This is the first study investigating the functionality of MeSH-dependent DMS production (Mdd) in a wide range of aerobic environments. All soils and marine sediment samples tested produced DMS when incubated with MeSH. Cultivation-dependent and cultivation-independent methods were used to assess microbial community changes in response to MeSH addition in a grassland soil where 35.9% of the bacteria were predicted to contain mddA. Bacteria of the genus Methylotenera were enriched in the presence of MeSH. Furthermore, many novel Mdd + bacterial strains were isolated. Despite the abundance of mddA in the grassland soil, the Mdd pathway may not be a significant source of DMS in this environment as MeSH addition was required to detect DMS at only very low conversion rates.

  2. Natural products in soil microbe interactions and evolution.

    Science.gov (United States)

    Traxler, Matthew F; Kolter, Roberto

    2015-07-01

    In recent years, bacterial interspecies interactions mediated by small molecule natural products have been found to give rise to a surprising array of phenotypes in soil-dwelling bacteria, especially among Streptomyces and Bacillus species. This review examines these interspecies interactions, and the natural products involved, as they have been presented in literature stemming from four disciplines: soil science, interspecies microbiology, ecology, and evolutionary biology. We also consider how these interactions fit into accepted paradigms of signaling, cueing, and coercion.

  3. Saline soil properties, quality and productivity of wheat grown with bagasse ash and thiourea in different climatic zones.

    Science.gov (United States)

    Seleiman, Mahmoud F; Kheir, Ahmed M S

    2018-02-01

    Soil salinity and atmosphere temperature change have negative impacts on crop productivity and its quality and can pose a significant risk to soil properties in semi-arid regions. We conducted two field experiments in North (first zone) and South (second zone) of Egypt to investigate the effects of soil bagasse ash (10 ton ha -1 ), foliar thiourea (240 g ha -1 ) and their combination in comparison to the control treatment on saline soil properties and productivity and quality traits of wheat. All studied treatments were received the recommended rate of N, P and K fertilizations. Combination of soil bagasse ash and foliar thiourea application resulted in a significant improvement of most studied soil properties (i.e. EC, compaction, hydraulic conductivity, OM and available P, K, N contents) after harvest in comparison to other treatments in both of zones. Also, it enhanced growth and grain yield of wheat in terms of photosynthesis related attributes and yield components. Moreover, combination of soil bagasse ash and foliar thiourea application resulted in superior grain quality traits in terms of carbohydrate, fibre, protein and ash contents than separated application of soil bagasse ash, foliar thiourea or even control treatment. In conclusion, combination of soil bagasse ash and foliar thiourea application can be used as suitable option to enhance plant nutrition, wheat productivity and improve wheat grain quality and soil traits in saline soil as well as can alleviate heat stress. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Application of Glomus sp. and Pseudomonas diminuta Reduce the Use of Chemical Fertilizers in Production of Potato Grown on Different Soil Types

    Science.gov (United States)

    Nurbaity, A.; Sofyan, E. T.; Hamdani, J. S.

    2016-08-01

    The use of high chemical fertilizer rates in potato production has been applied on the farm in Indonesia. Application of biofertilizer consists of arbuscular mycorrhizal fungi has been tested to reduce the use of NPK rates in production of potato and to determine whether different soil types will have different response to this biofertilizer. A greenhouse experiment was conducted using mixtures of spores of Glomus sp. and inoculant of mycorrhizal helper bacteria Pseudomonas diminuta, applied at different rates of NPK fertilizer (0, 25, 50, 75 and 100% of recommended rates) and different soil types (Andisols and Inceptisols). Results of experiment showed that application of Glomus sp. and P. diminuta reduced the use of NPK up to 50%, where the growth (plant height and tuber number), N,P,K uptake and tuber yields of potato had similar effect to the highest recommendation rate of NPK fertilizer. Inceptisols in general had better response to the biofertiliser compared to Andisols. Findings from this experiment confirmed the evidences that biofertilizer could reduce the use of chemical fertilizer, and the widely distributed soil in Indonesia such as Inceptisols, is potential to be used as a medium for potato production.

  5. N2O production pathways in the subtropical acid forest soils in China

    International Nuclear Information System (INIS)

    Zhang Jinbo; Cai Zucong; Zhu Tongbin

    2011-01-01

    To date, N 2 O production pathways are poorly understood in the humid subtropical and tropical forest soils. A 15 N-tracing experiment was carried out under controlled laboratory conditions to investigate the processes responsible for N 2 O production in four subtropical acid forest soils (pH 2 O emission in the subtropical acid forest soils, being responsible for 56.1%, 53.5%, 54.4%, and 55.2% of N 2 O production, in the GC, GS, GB, and TC soils, respectively, under aerobic conditions (40%-52%WFPS). The heterotrophic nitrification (recalcitrant organic N oxidation) accounted for 27.3%-41.8% of N 2 O production, while the contribution of autotrophic nitrification was little in the studied subtropical acid forest soils. The ratios of N 2 O-N emission from total nitrification (heterotrophic+autotrophic nitrification) were higher than those in most previous references. The soil with the lowest pH and highest organic-C content (GB) had the highest ratio (1.63%), suggesting that soil pH-organic matter interactions may exist and affect N 2 O product ratios from nitrification. The ratio of N 2 O-N emission from heterotrophic nitrification varied from 0.02% to 25.4% due to soil pH and organic matter. Results are valuable in the accurate modeling of N2O production in the subtropical acid forest soils and global budget. - Highlights: → We studied N 2 O production pathways in subtropical acid forest soil under aerobic conditions. → Denitrification was the main source of N 2 O production in subtropical acid forest soils. → Heterotrophic nitrification accounted for 27.3%-41.8% of N 2 O production. → While, contribution of autotrophic nitrification to N 2 O production was little. → Ratios of N 2 O-N emission from nitrification were higher than those in most previous references.

  6. Evaluating anaerobic soil disinfestation and other biological soil management methods for open-field tomato production in Florida

    Science.gov (United States)

    Anaerobic soil disinfestation (ASD), amending the soil with composted poultry litter (CPL) and molasses (M), has been shown to be a potential alternative to chemical soil fumigation for tomato production, however, optimization of ASD and the use of other biologically-based soil management practices ...

  7. Soil Tillage Conservation and its Effect on Soil Properties Bioremediation and Sustained Production of Crops

    Science.gov (United States)

    Rusu, Teodor; Ioana Moraru, Paula; Muresan, Liliana; Andriuca, Valentina; Cojocaru, Olesea

    2017-04-01

    Soil Tillage Conservation (STC) is considered major components of agricultural technology for soil conservation strategies and part of Sustainable Agriculture (SA). Human action upon soil by tillage determines important morphological, physical-chemical and biological changes, with different intensities and evaluative directions. Nowadays, internationally is unanimous accepted the fact that global climatic changes are the results of human intervention in the bio-geo-chemical water and material cycle, and the sequestration of carbon in soil is considered an important intervention to limit these changes. STC involves reducing the number of tillage's (minimum tillage) to direct sowing (no-tillage) and plant debris remains at the soil surface in the ratio of at least 30%. Plant debris left on the soil surface or superficial incorporated contributes to increased biological activity and is an important source of carbon sequestration. STC restore soil structure and improve overall soil drainage, allowing more rapid infiltration of water into soil. The result is a soil bioremediation, more productive, better protected against wind and water erosion and requires less fuel for preparing the germinative bed. Carbon sequestration in soil is net advantageous, improving the productivity and sustainability. We present the influence of conventional plough tillage system on soil, water and organic matter conservation in comparison with an alternative minimum tillage (paraplow, chisel plow and rotary harrow) and no-tillage system. The application of STC increased the organic matter content 0.8 to 22.1% and water stabile aggregate content from 1.3 to 13.6%, in the 0-30 cm depth, as compared to the conventional system. For the organic matter content and the wet aggregate stability, the statistical analysis of the data showed, increasing positive significance of STC. While the soil fertility and the wet aggregate stability were initially low, the effect of conservation practices on the

  8. Liming efficacy and transport in soil of a dry PFBC by-product

    International Nuclear Information System (INIS)

    Dick, W.A.

    1995-01-01

    The by-products of pressurized fluidized-bed combustion (PFBC) systems are mixtures of coal ash, anhydrite (CaSO 4 ), and unspent alkaline sorbent. Because PFBC by-products are alkaline and contain large concentrations of readily soluble bases (Ca and in some cases Mg) and other essential plant nutrients such as S and K, they have potential use as soil amendments, especially in acidic soils. PFBC by-products (particularly those with large Mg contents) may cause excessively high soluble salt concentrations when applied to soil. This could be detrimental to plant growth and might also impact the release of trace elements from the coal ash component of the by-product. In field experiments on three acidic soils, the liming effectiveness of a PFBC by-product, its effects on corn and alfalfa growth, and its impacts on crop, soil, and water quality were investigated

  9. Organic loading rates affect composition of soil-derived bacterial communities during continuous, fermentative biohydrogen production

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Yonghua; Bruns, Mary Ann [Department of Crop and Soil Sciences, The Pennsylvania State University, University Park, PA 16802 (United States); Zhang, Husen; Salerno, Michael; Logan, Bruce E. [Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, PA 16802 (United States)

    2008-11-15

    Bacterial community composition during steady-state, fermentative H{sub 2} production was compared across a range of organic loading rates (OLRs) of 0.5-19 g COD l{sup -1} h{sup -1} in a 2-l continuous flow reactor at 30 C. The varied OLRs were achieved with glucose concentrations of 2.5-10 g l{sup -1} and hydraulic retention times of 1-10 h. The synthetic wastewater feed was amended with L-cysteine and maintained at a pH of 5.5. For each run at a given glucose concentration, the reactor was inoculated with an aliquot of well-mixed agricultural topsoil that had been heat-treated to reduce numbers of vegetative cells. At OLRs less than 2 g COD l{sup -1} h{sup -1}, DNA sequences from ribosomal RNA intergenic spacer analysis profiles revealed more diverse and variable populations (Selenomonas, Enterobacter, and Clostridium spp.) than were observed above 2 g COD l{sup -1} h{sup -1} (Clostridium spp. only). An isolate, LYH1, was cultured from a reactor sample (10 g glucose l{sup -1} at a 10-h HRT) on medium containing L-cysteine. In confirming H{sub 2} production by LYH1 in liquid batch culture, lag periods for H{sub 2} production in the presence and absence of L-cysteine were 5 and 50 h, respectively. The 16S rRNA gene sequence of LYH1 indicated that the isolate was a Clostridium sp. affiliated with RNA subcluster Ic, with >99% similarity to Clostridium sp. FRB1. In fluorescent in situ hybridization tests, an oligonucleotide probe complementary to the 16S rRNA of LYH1 hybridized with 90% of cells observed at an OLR of 2 g COD h{sup -1}, compared to 26% of cells at an OLR of 0.5 g COD l{sup -1} h{sup -1}. An OLR of 2 g COD l{sup -1} h{sup -1} appeared to be a critical threshold above which clostridia were better able to outcompete Enterobacteriaceae and other organisms in the mixed soil inoculum. Our results are discussed in light of other biohydrogen studies employing pure cultures and mixed inocula. (author)

  10. Assessing soil quality: practicable standards for sustainable forest productivity in the United States

    Science.gov (United States)

    Robert F. Powers; Allan E. Tiarks; James R. Boyle

    1998-01-01

    Productive soils form the foundation for productive forests. But unfortunately, the significance of soil seems lost to modem society. Most of us are too far removed from the natural factors of production to appreciate the multiple roles of soil. Nor is its worth recognized well by many forest managers who too often see soil only in its capacity for logging roads and...

  11. Forest soil mineral weathering rates: use of multiple approaches

    Science.gov (United States)

    Randy K. Kolka; D.F. Grigal; E.A. Nater

    1996-01-01

    Knowledge of rates of release of base cations from mineral dissolution (weathering) is essential to understand ecosystem elemental cycling. Although much studied, rates remain enigmatic. We compared the results of four methods to determine cation (Ca + Mg + K) release rates at five forested soils/sites in the northcentral U.S.A. Our premise was that multiple...

  12. Dry flue gas desulfurization by-product application effects on plant uptake and soil storage changes in a managed grassland.

    Science.gov (United States)

    Burgess-Conforti, Jason R; Brye, Kristofor R; Miller, David M; Pollock, Erik D; Wood, Lisa S

    2018-02-01

    Environmental regulations mandate that sulfur dioxide (SO 2 ) be removed from the flue gases of coal-fired power plants, which results in the generation of flue gas desulfurization (FGD) by-products. These FGD by-products may be a viable soil amendment, but the large amounts of trace elements contained in FGD by-products are potentially concerning. The objective of this study was to evaluate the effects of land application of a high-Ca dry FGD (DFGD) by-product on trace elements in aboveground biomass and soil. A high-Ca DFGD by-product was applied once at a rate of 9 Mg ha -1 on May 18, 2015 to small plots with mixed-grass vegetation. Soil and biomass were sampled prior to application and several times thereafter. Aboveground dry matter and tissue As, Co, Cr, Hg, Se, U, and V concentrations increased (P  0.05) from pre-application levels or the unamended control within 3 to 6 months of application. Soil pH in the amended treatment 6 months after application was greater (P by-product application compared to the unamended control. High-Ca DFGD by-products appear to be useful as a soil amendment, but cause at least a temporary increase in tissue concentrations of trace elements, which may be problematic for animal grazing situations.

  13. Prediction of Soil Erosion Rates in Japan where Heavily Forested Landscape with Unstable Terrain

    Science.gov (United States)

    Nanko, K.; Oguro, M.; Miura, S.; Masaki, T.

    2016-12-01

    Soil is fundamental for plant growth, water conservation, and sustainable forest management. Multidisciplinary interest in the role of the soil in areas such as biodiversity, ecosystem services, land degradation, and water security has been growing (Miura et al., 2015). Forest is usually protective land use from soil erosion because vegetation buffers rainfall power and erosivity. However, some types of forest in Japan show high susceptibility to soil erosion due to little ground cover and steep slopes exceeding thirty degree, especially young Japanese cypress (Chamaecyparis obtusa) plantations (Miura et al., 2002). This is a critical issue for sustainable forest management because C. obtusaplantations account for 10% of the total forest coverage in Japan (Forestry Agency, 2009). Prediction of soil erosion rates on nationwide scale is necessary to make decision for future forest management plan. To predict and map soil erosion rates across Japan, we applied three soil erosion models, RUSLE (Revised Universal Soil Loss Equation, Wischmeier and Smith, 1978), PESERA (Pan-European Soil Erosion Risk Assessment, Kirkby et al., 2003), and RMMF (Revised Morgan-Morgan-Finney, Morgan, 2001). The grid scale is 1-km. RUSLE and PESERA are most widely used erosion models today. RMMF includes interactions between rainfall and vegetation, such as canopy interception and ratio of canopy drainage in throughfall. Evaporated rainwater by canopy interception, generally accounts for 15-20% in annual rainfall, does not contribute soil erosion. Whereas, larger raindrops generated by canopy drainage produced higher splash erosion rates than gross rainfall (Nanko et al., 2008). Therefore, rainfall redistribution process in canopy should be considered to predict soil erosion rates in forested landscape. We compared the results from three erosion models and analyze the importance of environmental factors for the prediction of soil erosion rates. This research was supported by the Environment

  14. Three-year study of fast-growing trees in degraded soils amended with composts: Effects on soil fertility and productivity.

    Science.gov (United States)

    Madejón, Paula; Alaejos, Joaquin; García-Álbala, José; Fernández, Manuel; Madejón, Engracia

    2016-03-15

    Currently, worries about the effects of intensive plantations on long-term nutrient supply and a loss of productivity have risen. In this study two composts were added to degraded soils where this type of intensive crops were growing, to avoid the soil fertility decrease and try to increase biomass production. For the experiment, two degraded soils in terms of low organic carbon content and low pH were selected in South-West Spain: La Rábida (RA) and Villablanca (VI) sites. Both study sites were divided into 24 plots. In RA, half of the plots were planted with Populus x canadensis "I-214"; the other half was planted with Eucalyptus globulus. At the VI site, half of the plots were planted with Paulownia fortunei, and the other plots were planted with Eucalyptus globulus. For each tree and site, three treatments were established (two organic composts and a control without compost), with four replications per treatment. The organic amendments were "alperujo" compost, AC, a solid by-product from the extraction of olive oil, and BC, biosolid compost. During the three years of experimentation, samples of soils and plants were analyzed for studying chemical and biochemical properties of soil, plant growth and plant nutritional status and biomass production. The composts increased total organic carbon, water-soluble carbon, nutrients and pH of soil only in the most acidic soil. Soil biochemical quality was calculated with the geometric mean of the enzymatic activities (Dehydrogenase, β-glucosidase, Phosphatase and Urease activities) determined in soils. The results showed a beneficial improvement in comparison with soils without compost. However, the best results were found in the growth and biomass production of the studied trees, especially in Eucalyptus. Nutritional levels of leaves of the trees were, in general, in the normal established range for each species, although no clear effect of the composts was observed. The results of this study justify the addition of

  15. Soil salinity decreases global soil organic carbon stocks.

    Science.gov (United States)

    Setia, Raj; Gottschalk, Pia; Smith, Pete; Marschner, Petra; Baldock, Jeff; Setia, Deepika; Smith, Jo

    2013-11-01

    Saline soils cover 3.1% (397 million hectare) of the total land area of the world. The stock of soil organic carbon (SOC) reflects the balance between carbon (C) inputs from plants, and losses through decomposition, leaching and erosion. Soil salinity decreases plant productivity and hence C inputs to the soil, but also microbial activity and therefore SOC decomposition rates. Using a modified Rothamsted Carbon model (RothC) with a newly introduced salinity decomposition rate modifier and a plant input modifier we estimate that, historically, world soils that are currently saline have lost an average of 3.47 tSOC ha(-1) since they became saline. With the extent of saline soils predicted to increase in the future, our modelling suggests that world soils may lose 6.8 Pg SOC due to salinity by the year 2100. Our findings suggest that current models overestimate future global SOC stocks and underestimate net CO2 emissions from the soil-plant system by not taking salinity effects into account. From the perspective of enhancing soil C stocks, however, given the lower SOC decomposition rate in saline soils, salt tolerant plants could be used to sequester C in salt-affected areas. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Radon and Thoron Exhalation Rates from Surface Soil of Bangka - Belitung Islands, Indonesia

    Directory of Open Access Journals (Sweden)

    Syarbaini Syarbaini

    2015-03-01

    Full Text Available DOI:10.17014/ijog.2.1.35-42Radon and thoron exhalation rate from soil is one of the most important factors that can influence the radioactivity level in the environment. Radon and thoron gases are produced by the decay of the radioactive elements those are radium and thorium in the soil, where its concentration depends on the soil conditions and the local geological background. In this paper, the results of radon and thoron exhalation rate measurements from surface soil of Bangka Belitung Islands at thirty six measurement sites are presented. Exhalation rates of radon and thoron were measured by using an accumulation chamber equipped with a solid-state alpha particle detector. Furthermore, the correlations between radon and thoron exhalation rates with their parent nuclide (226Ra and 232Th concentrations in collected soil samples from the same locations were also evaluated. The result of the measurement shows that mostly the distribution of radon and thoron is similar to 226Ra and 232Th, eventhough it was not a good correlation between radon and thoron exhalation rate with their parent activity concentrations (226Ra and 232Th due to the environmental factors that can influence the radon and thoron mobilities in the soil. In comparison to a world average, Bangka Belitung Islands have the 222Rn and 220Rn exhalation rates higher than the world average value for the regions with normal background radiation.

  17. Introducing a decomposition rate modifier in the Rothamsted Carbon Model to predict soil organic carbon stocks in saline soils.

    Science.gov (United States)

    Setia, Raj; Smith, Pete; Marschner, Petra; Baldock, Jeff; Chittleborough, David; Smith, Jo

    2011-08-01

    Soil organic carbon (SOC) models such as the Rothamsted Carbon Model (RothC) have been used to estimate SOC dynamics in soils over different time scales but, until recently, their ability to accurately predict SOC stocks/carbon dioxide (CO(2)) emissions from salt-affected soils has not been assessed. Given the large extent of salt-affected soils (19% of the 20.8 billion ha of arable land on Earth), this may lead to miss-estimation of CO(2) release. Using soils from two salt-affected regions (one in Punjab, India and one in South Australia), an incubation study was carried out measuring CO(2) release over 120 days. The soils varied both in salinity (measured as electrical conductivity (EC) and calculated as osmotic potential using EC and water content) and sodicity (measured as sodium adsorption ratio, SAR). For soils from both regions, the osmotic potential had a significant positive relationship with CO(2)-C release, but no significant relationship was found between SAR and CO(2)-C release. The monthly cumulative CO(2)-C was simulated using RothC. RothC was modified to take into account reductions in plant inputs due to salinity. A subset of non-salt-affected soils was used to derive an equation for a "lab-effect" modifier to account for changes in decomposition under lab conditions and this modifier was significantly related with pH. Using a subset of salt-affected soils, a decomposition rate modifier (as a function of osmotic potential) was developed to match measured and modelled CO(2)-C release after correcting for the lab effect. Using this decomposition rate modifier, we found an agreement (R(2) = 0.92) between modelled and independently measured data for a set of soils from the incubation experiment. RothC, modified by including reduced plant inputs due to salinity and the salinity decomposition rate modifier, was used to predict SOC stocks of soils in a field in South Australia. The predictions clearly showed that SOC stocks are reduced in saline soils

  18. Open charcoal chamber method for mass measurements of radon exhalation rate from soil surface

    International Nuclear Information System (INIS)

    Tsapalov, Andrey; Kovler, Konstantin; Miklyaev, Peter

    2016-01-01

    Radon exhalation rate from the soil surface can serve as an important criterion in the evaluation of radon hazard of the land. Recently published international standard ISO 11665-7 (2012) is based on the accumulation of radon gas in a closed container. At the same time since 1998 in Russia, as a part of engineering and environmental studies for the construction, radon flux measurements are made using an open charcoal chamber for a sampling duration of 3–5 h. This method has a well-defined metrological justification and was tested in both favorable and unfavorable conditions. The article describes the characteristics of the method, as well as the means of sampling and measurement of the activity of radon absorbed. The results of the metrological study suggest that regardless of the sampling conditions (weather, the mechanism and rate of radon transport in the soil, soil properties and conditions), uncertainty of method does not exceed 20%, while the combined standard uncertainty of radon exhalation rate measured from the soil surface does not exceed 30%. The results of the daily measurements of radon exhalation rate from the soil surface at the experimental site during one year are reported. - Highlights: • Radon exhalation rate from the soil surface area of 32 cm"2 can be measured at level of 10 mBq/(m"2s) at the uncertainty ≤30%. • The method has a metrological justification. • No need to consider climate conditions, soil properties and conditions, mechanism and rate of radon transport in the soil.

  19. Long-term flow rates and biomat zone hydrology in soil columns receiving septic tank effluent.

    Science.gov (United States)

    Beal, C D; Gardner, E A; Kirchhof, G; Menzies, N W

    2006-07-01

    Soil absorption systems (SAS) are used commonly to treat and disperse septic tank effluent (STE). SAS can hydraulically fail as a result of the low permeable biomat zone that develops on the infiltrative surface. The objectives of this experiment were to compare the hydraulic properties of biomats grown in soils of different textures, to investigate the long-term acceptance rates (LTAR) from prolonged application of STE, and to assess if soils were of major importance in determining LTAR. The STE was applied to repacked sand, Oxisol and Vertisol soil columns over a period of 16 months, at equivalent hydraulic loading rates of 50, 35 and 8L/m(2)/d, respectively. Infiltration rates, soil matric potentials, and biomat hydraulic properties were measured either directly from the soil columns or calculated using established soil physics theory. Biomats 1 to 2 cm thick developed in all soils columns with hydraulic resistances of 27 to 39 d. These biomats reduced a 4 order of magnitude variation in saturated hydraulic conductivity (K(s)) between the soils to a one order of magnitude variation in LTAR. A relationship between biomat resistance and organic loading rate was observed in all soils. Saturated hydraulic conductivity influenced the rate and extent of biomat development. However, once the biomat was established, the LTAR was governed by the resistance of the biomat and the sub-biomat soil unsaturated flow regime induced by the biomat. Results show that whilst initial soil K(s) is likely to be important in the establishment of the biomat zone in a trench, LTAR is determined by the biomat resistance and the unsaturated soil hydraulic conductivity, not the K(s) of a soil. The results call into question the commonly used approach of basing the LTAR, and ultimately trench length in SAS, on the initial K(s) of soils.

  20. Soil fertility and soil loss constraints on crop residue removal for energy production

    Energy Technology Data Exchange (ETDEWEB)

    Flaim, S.

    1979-07-01

    A summary of the methodologies used to estimate the soil fertility and soil loss constraints on crop residue removal for energy production is presented. Estimates of excess residue are developed for wheat in north-central Oklahoma and for corn and soybeans in central Iowa. These sample farming situations are analyzed in other research in the Analysis Division of the Solar Energy Research Institute.

  1. Permafrost thawing in organic Arctic soils accelerated by ground heat production

    DEFF Research Database (Denmark)

    Hollesen, Jørgen; Matthiesen, Henning; Møller, Anders Bjørn

    2015-01-01

    Decomposition of organic carbon from thawing permafrost soils and the resulting release of carbon to the atmosphere are considered to represent a potentially critical global-scale feedback on climate change1, 2. The accompanying heat production from microbial metabolism of organic material has been...... recognized as a potential positive-feedback mechanism that would enhance permafrost thawing and the release of carbon3, 4. This internal heat production is poorly understood, however, and the strength of this effect remains unclear3. Here, we have quantified the variability of heat production in contrasting...... organic permafrost soils across Greenland and tested the hypothesis that these soils produce enough heat to reach a tipping point after which internal heat production can accelerate the decomposition processes. Results show that the impact of climate changes on natural organic soils can be accelerated...

  2. A soil-specific agro-ecological strategy for sustainable production in Argentina farm fields

    Science.gov (United States)

    Zamora, Martin; Barbera, Agustin; Castro-Franco, Mauricio; Hansson, Alejandro; Domenech, Marisa

    2017-04-01

    The continuous increment of frequencies and doses of pesticides, glyphosate and fertilizers, the deterioration of the structure, biotic balance and fertility of soils and the ground water pollution are characteristics of the current Argentinian agricultural model. In this context, agro-ecological innovations are needed to develop a real sustainable agriculture, enhancing the food supply. Precision agriculture technologies can strengthen the expansion of agro-ecological farming in experimental farm fields. The aim of this study was to propose a soil-specific agro-ecological strategy for sustainable production at field scale focused on the use of soil sensors and digital soil mapping techniques. This strategy has been developed in 15 hectares transition agro-ecological farm field, located at Barrow Experimental Station (Lat:-38.322844, Lon:-60.25572) Argentina. The strategy included five steps: (i) to measure apparent electrical conductivity (ECa) and elevation within agro-ecological farm field; (ii) to apply a clustering method using MULTISPATI-PCA algorithm to delimitate three soil-specific zones (Z1, Z2 and Z3); (iii) to determine three soil sampling points by zone, using conditioned Latin hypercube method, in addition to elevation and ECa as auxiliary information; (iv) to collect soil samples at 2-10 cm depth in each point and to determine in laboratory: total organic carbon content (TOC), cation-exchange capacity (CEC), pH and phosphorus availability (P-Bray). In addition, soil bulk density (SBD) was measured at 0-20 cm depth. Finally, (v) according to each soil-specific zone, a management strategy was recommended. Important differences in soil properties among zones could suggest that the strategy developed was able to apply an agro ecological soil-specific practice management. pH and P-Bray were significantly (pfertilizer and also rotating plots with high stocking rate. The aim is to increase soil organic matter content and CEC. Furthermore, P content will be

  3. Fuelwood production potential of six Prosopis species on an alkaline soil site

    Energy Technology Data Exchange (ETDEWEB)

    Goel, V.L.; Behl, H.M. [National Botanical Research Inst., Lucknow (India). Biomass Research Center

    1995-07-01

    The biomass potential of six species Prosopis was evaluated on highly alkaline soil site. Prosopis alba I was found to have the fastest growth rate and highest above-ground biomass production. P. juliflora ranked next. P. cineraria showed high plant establishment but relatively slow growth. The performance of P. glandulosa was poor on such sites. The high fuelwood value index and rapid growth rate of P. juliflora and P. alba makes them suitable for short-rotation fuelwood forestry programmes on waste-lands. Selection of promising genotypes is suggested as a means of improvement in yields. (author)

  4. Soil Carbon Dioxide Production and Surface Fluxes: Subsurface Physical Controls

    Science.gov (United States)

    Risk, D.; Kellman, L.; Beltrami, H.

    Soil respiration is a critical determinant of landscape carbon balance. Variations in soil temperature and moisture patterns are important physical processes controlling soil respiration which need to be better understood. Relationships between soil respi- ration and physical controls are typically addressed using only surface flux data but other methods also exist which permit more rigorous interpretation of soil respira- tion processes. Here we use a combination of subsurface CO_{2} concentrations, surface CO_{2} fluxes and detailed physical monitoring of the subsurface envi- ronment to examine physical controls on soil CO_{2} production at four climate observatories in Eastern Canada. Results indicate that subsurface CO_{2} produc- tion is more strongly correlated to the subsurface thermal environment than the surface CO_{2} flux. Soil moisture was also found to have an important influence on sub- surface CO_{2} production, particularly in relation to the soil moisture - soil profile diffusivity relationship. Non-diffusive profile CO_{2} transport appears to be im- portant at these sites, resulting in a de-coupling of summertime surface fluxes from subsurface processes and violating assumptions that surface CO_{2} emissions are the result solely of diffusion. These results have implications for the study of soil respiration across a broad range of terrestrial environments.

  5. Soil quality assessment in rice production systems

    NARCIS (Netherlands)

    Rodrigues de Lima, A.C.

    2007-01-01

    In the state of Rio Grande do Sul, Brazil, rice production is one of the most important regional activities. Farmers are concerned that the land use practices for rice production in the Camaquã region may not be sustainable because of detrimental effects on soil quality. The study presented in this

  6. Soil respiration patterns and rates at three Taiwanese forest plantations: dependence on elevation, temperature, precipitation, and litterfall.

    Science.gov (United States)

    Huang, Yu-Hsuan; Hung, Chih-Yu; Lin, I-Rhy; Kume, Tomonori; Menyailo, Oleg V; Cheng, Chih-Hsin

    2017-11-15

    Soil respiration contributes to a large quantity of carbon emissions in the forest ecosystem. In this study, the soil respiration rates at three Taiwanese forest plantations (two lowland and one mid-elevation) were investigated. We aimed to determine how soil respiration varies between lowland and mid-elevation forest plantations and identify the relative importance of biotic and abiotic factors affecting soil respiration. The results showed that the temporal patterns of soil respiration rates were mainly influenced by soil temperature and soil water content, and a combined soil temperature and soil water content model explained 54-80% of the variation. However, these two factors affected soil respiration differently. Soil temperature positively contributed to soil respiration, but a bidirectional relationship between soil respiration and soil water content was revealed. Higher soil moisture content resulted in higher soil respiration rates at the lowland plantations but led to adverse effects at the mid-elevation plantation. The annual soil respiration rates were estimated as 14.3-20.0 Mg C ha -1  year -1 at the lowland plantations and 7.0-12.2 Mg C ha -1  year -1 at the mid-elevation plantation. When assembled with the findings of previous studies, the annual soil respiration rates increased with the mean annual temperature and litterfall but decreased with elevation and the mean annual precipitation. A conceptual model of the biotic and abiotic factors affecting the spatial and temporal patterns of the soil respiration rate was developed. Three determinant factors were proposed: (i) elevation, (ii) stand characteristics, and (iii) soil temperature and soil moisture. The results indicated that changes in temperature and precipitation significantly affect soil respiration. Because of the high variability of soil respiration, more studies and data syntheses are required to accurately predict soil respiration in Taiwanese forests.

  7. Intercropping enhances productivity and maintains the most soil fertility properties relative to sole cropping.

    Directory of Open Access Journals (Sweden)

    Zhi-Gang Wang

    Full Text Available Yield and nutrient acquisition advantages are frequently found in intercropping systems. However, there are few published reports on soil fertility in intercropping relative to monocultures. A field experiment was therefore established in 2009 in Gansu province, northwest China. The treatments comprised maize/faba bean, maize/soybean, maize/chickpea and maize/turnip intercropping, and their correspoding monocropping. In 2011 (the 3rd year and 2012 (the 4th year the yields and some soil chemical properties and enzyme activities were examined after all crop species were harvested or at later growth stages. Both grain yields and nutrient acquisition were significantly greater in all four intercropping systems than corresponding monocropping over two years. Generally, soil organic matter (OM did not differ significantly from monocropping but did increase in maize/chickpea in 2012 and maize/turnip in both years. Soil total N (TN did not differ between intercropping and monocropping in either year with the sole exception of maize/faba bean intercropping receiving 80 kg P ha-1 in 2011. Intercropping significantly reduced soil Olsen-P only in 2012, soil exchangeable K in both years, soil cation exchangeable capacity (CEC in 2012, and soil pH in 2012. In the majority of cases soil enzyme activities did not differ across all the cropping systems at different P application rates compared to monocrops, with the exception of soil acid phosphatase activity which was higher in maize/legume intercropping than in the corresponding monocrops at 40 kg ha-1 P in 2011. P fertilization can alleviate the decline in soil Olsen-P and in soil CEC to some extent. In summary, intercropping enhanced productivity and maintained the majority of soil fertility properties for at least three to four years, especially at suitable P application rates. The results indicate that maize-based intercropping may be an efficient cropping system for sustainable agriculture with carefully

  8. Enhancing productivity of salt affected soils through crops and cropping system

    International Nuclear Information System (INIS)

    Singh, S.S.; Khan, A.R.

    2002-05-01

    The reclamation of salt affected soils needs the addition of soil amendment and enough water to leach down the soluble salts. The operations may also include other simple agronomic techniques to reclaim soils and to know the crops and varieties that may be grown and other management practices which may be followed on such soils (Khan, 2001). The choice of crops to be grown during reclamation of salt affected soils is very important to obtain acceptable yields. This also decides cropping systems as well as favorable diversification for early reclamation, desirable yield and to meet the other requirements of farm families. In any salt affected soils, the following three measures are adopted for reclamation and sustaining the higher productivity of reclaimed soils. 1. Suitable choice of crops, forestry and tree species; 2. Suitable choice of cropping and agroforestry system; 3. Other measures to sustain the productivity of reclaimed soils. (author)

  9. The Impact of the Quality of Coal Mine Stockpile Soils on Sustainable Vegetation Growth and Productivity

    Directory of Open Access Journals (Sweden)

    Nicky M Mushia

    2016-06-01

    Full Text Available Stockpiled soils are excavated from the ground during mining activities, and piled on the surface of the soil for rehabilitation purposes. These soils are often characterized by low organic matter (SOM content, low fertility, and poor physical, chemical, and biological properties, limiting their capability for sustainable vegetation growth. The aim of the study was to evaluate the impact of stockpile soils of differing depth and quality on vegetation growth and productivity. Soils were collected at three different depths (surface, mid, and deep as well as mixed (equal proportion of surface, mid and deep from two stockpiles (named Stockpile 1: aged 10 and Stockpile 2: 20 years at the coal mine near Witbank in the Mpumalanga province of South Africa. Soils were amended with different organic and inorganic fertilizer. A 2 × 4 × 5 factorial experiment in a completely randomized blocked design with four replications was established under greenhouse conditions. A grass species (Digiteria eriantha was planted in the pots with unamended and amended soils under greenhouse conditions at 26–28 °C during the day and 16.5–18.5 °C at night. Mean values of plant height, plant cover, total fresh biomass (roots, stems and leaves, and total dry biomass were found to be higher in Stockpile 1 than in Stockpile 2 soils. Plants grown on soils with no amendments had lower mean values for major plant parameters studied. Soil amended with poultry manure and lime was found to have higher growth rate compared with soils with other soil amendments. Mixed soils had better vegetation growth than soil from other depths. Stockpiled soils in the study area cannot support vegetation growth without being amended, as evidenced by low grass growth and productivity in this study.

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

    Directory of Open Access Journals (Sweden)

    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

  11. Frost heave susceptibility of saturated soil under constant rate of freezing

    Science.gov (United States)

    Ryokai, K.; Iguro, M.; Yoneyama, K.

    Introduced are the results of experiments carried out to quantitatively obtain the frost heave pressure and displacement of soil subjected to artificial freezing or freezing around in-ground liquefied natural gas storage tanks. This experiment is conducted to evaluate the frost heave susceptibility of saturated soil under overconsolidation. In other words, this experiment was carried out to obtain the relation of the over-burden pressure and freezing rate to the frost heave ratio by observing the frost heave displacement and freezing time of specimens by freezing the specimens at a constant freezing rate under a constant overburden pressure, while letting water freely flow in and out of the system. Introduced are the procedures for frost heave test required to quantitatively obtain the frost heave displacement and pressure of soil. Furthermore, the relation between the frost heave susceptibility and physical properties of soil obtained by this test is reported.

  12. Correlation indices physical space of soil and productivity of fruit tomato industry

    Directory of Open Access Journals (Sweden)

    Danilo Gomes de Oliveira

    2017-12-01

    Full Text Available With mechanization at all stages of crop management, the soil began to receive a higher surface load, which causes changes in its physical properties with possible production impacts. Thus, the objective of this work was to evaluate the variability and spatial correlation of the physical attributes of a Red Latosol with the productivity of industrial tomatoes. For this, a sample mesh was assembled using a global receiver positioning system (GPS, with 84 pairs of spaced apart 80 x 80 m points. After the mesh construction, samples in the 0.00-0.20 m layer were collected in the field to measure the physical attributes of the soil and plant data. The variables measured were: soil density (Ds, soil penetration resistance (PR, soil texture and tomato productivity. The values obtained were analyzed using geostatistics, and were classified according to the degree of spatial dependence. Then, using the ordinary kriging interpolation method and ordinary cokriging, the values for nonsampled sites were estimated, allowing the mapping of isovalues and the definition of management zones in the field. The spatial correlation of the physical attributes with the production components by the ordinary Cokriging method verified spatial correlation only between attributes (soil x soil density and sand content. The use of geostatistics and the construction of the maps by means of kriging and ordinary cokrigation allowed to identify different management zones, that is, the variability of soil attributes and productivity.

  13. Accelerated decay rates drive soil organic matter persistence and storage in temperate forests via greater mineral stabilization of microbial residues.

    Science.gov (United States)

    Phillips, R.; Craig, M.; Turner, B. L.; Liang, C.

    2017-12-01

    Climate predicts soil organic matter (SOM) stocks at the global scale, yet controls on SOM stocks at finer spatial scales are still debated. A current hypothesis predicts that carbon (C) and nitrogen (N) storage in soils should be greater when decomposition is slow owing to microbial competition for nutrients or the recalcitrance of organic substrates (hereafter the `slow decay' hypothesis). An alternative hypothesis predicts that soil C and N storage should be greater in soils with rapid decomposition, owing to the accelerated production of microbial residues and their stabilization on soil minerals (hereafter the `stabilization hypothesis'). To test these alternative hypotheses, we quantified soil C and N to 1-m depth in temperate forests across the Eastern and Midwestern US that varied in their biotic, climatic, and edaphic properties. At each site, we sampled (1) soils dominated by arbuscular mycorrhizal (AM) tree species, which typically have fast decay rates and accelerated N cycling, (2) soils dominated by ectomycorrhizal (ECM) tree species, which generally have slow decay rates and slow N cycling, and (3) soils supporting both AM and ECM trees. To the extent that trees and theor associated microbes reflect and reinforce soil conditions, support for the slow decay hypothesis would be greater SOM storage in ECM soils, whereas support for the stabilization hypothesis would be greater SOM storage in AM soils. We found support for both hypotheses, as slow decomposition in ECM soils increased C and N storage in topsoil, whereas fast decomposition in AM soils increased C and N storage in subsoil. However, at all sites we found 57% greater total C and N storage in the entire profile in AM- soils (P stabilization hypothesis. Amino sugar biomarkers (an indicator of microbial necromass) and particle size fractionation revealed that the greater SOM storage in AM soils was driven by an accumulation of microbial residues on clay minerals and metal oxides. Taken together

  14. Effect of Impact Angle on the Erosion Rate of Coherent Granular Soil, with a Chernozemic Soil as an Example

    Science.gov (United States)

    Larionov, G. A.; Bushueva, O. G.; Gorobets, A. V.; Dobrovol'skaya, N. G.; Kiryukhina, Z. P.; Krasnov, S. F.; Kobylchenko Kuksina, L. V.; Litvin, L. F.; Sudnitsyn, I. I.

    2018-02-01

    It has been shown in experiments in a hydraulic flume with a knee-shaped bend that the rate of soil erosion more than doubles at the flow impact angles to the channel side from 0° to 50°. At higher channel bends, the experiment could not be performed because of backwater. Results of erosion by water stream approaching the sample surface at angles between 2° and 90° are reported. It has been found that the maximum erosion rate is observed at flow impact angles of about 45°, and the minimum rate at 90°. The minimum soil erosion rate is five times lower than the maximum erosion rate. This is due to the difference in the rate of free water penetration into the upper soil layer, and the impact of the hydrodynamic pressure, which is maximum at the impact angle of 90°. The penetration of water into the interaggregate space results in the breaking of bonds between aggregates, which is the main condition for the capture of particles by the flow.

  15. Absorption of gamma-emitting fission products and activation products by rice under flooded and unflooded conditions from two tropical soils

    International Nuclear Information System (INIS)

    D'Souza, T.J.; Mistry, K.B.

    1980-01-01

    The absorption of gamma-emitting fission products 106 Ru, 125 Sb, 137 Cs and 144 Ce and activation products 59 Fe, 58 Co, 54 Mn and 65 Zn by rice plants grown on two contrasting tropical soils, namely, a blak soil (pellustert) and a laterite (oxisol), and the effects of flooding were studied under controlled conditions. Results indicated greater uptake of 106 Ru and 125 Sb from the black soil than from the laterite. In contrast, the uptake of 144 Ce and 137 Cs was greater in the laterite than in the black soil. Flooding treatment enhanced the uptake of all these fission products by rice plants in the laterite soil whereas this effect was observed only for 125 Sb and 137 Cs in the black soil. The plant uptake of activation products from the two soil types showed maximum accumulation of 65 Zn followed by 54 Mn, 59 Fe and 58 Co in both soil types. Besides, uptake of these nuclides was greater from the laterite soil than from the black soil. Flooding treatment for rice while showing a reduction of 59 Fe uptake showed an increase in plant uptake of 58 Co, 54 Mn and 65 Zn in both soil types. (orig.)

  16. Final Progress Report on Model-Based Diagnosis of Soil Limitations to Forest Productivity

    Energy Technology Data Exchange (ETDEWEB)

    Luxmoore, R.J.

    2004-08-30

    This project was undertaken in support of the forest industry to link modeling of nutrients and productivity with field research to identify methods for enhancing soil quality and forest productivity and for alleviating soil limitations to sustainable forest productivity. The project consisted of a series of related tasks, including (1) simulation of changes in biomass and soil carbon with nitrogen fertilization, (2) development of spreadsheet modeling tools for soil nutrient availability and tree nutrient requirements, (3) additional modeling studies, and (4) evaluation of factors involved in the establishment and productivity of southern pine plantations in seasonally wet soils. This report also describes the two Web sites that were developed from the research to assist forest managers with nutrient management of Douglas-fir and loblolly pine plantations.

  17. Downscaling Coarse Scale Microwave Soil Moisture Product using Machine Learning

    Science.gov (United States)

    Abbaszadeh, P.; Moradkhani, H.; Yan, H.

    2016-12-01

    Soil moisture (SM) is a key variable in partitioning and examining the global water-energy cycle, agricultural planning, and water resource management. It is also strongly coupled with climate change, playing an important role in weather forecasting and drought monitoring and prediction, flood modeling and irrigation management. Although satellite retrievals can provide an unprecedented information of soil moisture at a global-scale, the products might be inadequate for basin scale study or regional assessment. To improve the spatial resolution of SM, this work presents a novel approach based on Machine Learning (ML) technique that allows for downscaling of the satellite soil moisture to fine resolution. For this purpose, the SMAP L-band radiometer SM products were used and conditioned on the Variable Infiltration Capacity (VIC) model prediction to describe the relationship between the coarse and fine scale soil moisture data. The proposed downscaling approach was applied to a western US basin and the products were compared against the available SM data from in-situ gauge stations. The obtained results indicated a great potential of the machine learning technique to derive the fine resolution soil moisture information that is currently used for land data assimilation applications.

  18. A Preliminary Study on Termite Mound Soil as Agricultural Soil for Crop Production in South West, Nigeria

    Directory of Open Access Journals (Sweden)

    O. E. Omofunmi

    2017-08-01

    Full Text Available It is a popular belief of the people in the Southern region of Nigeria that a land infested with termite usually brings prosperity to the land owner regardless of the type of its usage. Therefore, the present study assessed termite mounds soil properties which are important to crop production. Two soil samples were collected and their physical and chemical properties determined in accordance with American Public Health Association (APHA, 2005. Data were analyzed using descriptive statistics. The textural classes showed that the termite mound soil was sand clay loam while the surrounding soil was clay loam. This results revealed that: Termites’ activity induced significant chemical changes in the soil possible due to the materials used in building their nests. There was increase the concentrations of nitrogen, phosphorus, Potassium, calcium and magnesium higher in the termite’s mounds, while the micro-nutrients (zinc, iron and copper except sulphur and manganese lower in the soil infested by termites. There were significant differences (p ≥ 0.05 between termite mound soil and surrounding soil. It showed highly positive correlation between termite mound and surrounding soil (r= 0.92. The concentration of the soil properties around the termite mound are within the range of soil nutrients suitable for arable crop production. Termite mound soil is recommended to be used as an alternative to local farmers who cannot afford to buy expensive inorganic fertilizers.

  19. Flood effects on efflux and net production of nitrous oxide in river floodplain soils

    Science.gov (United States)

    Riaz, Muhammad; Bruderer, Christian; Niklaus, Pascal A.; Luster, Jörg

    2016-04-01

    Floodplain soils are often rich in nutrients and exhibit high spatial heterogeneity in terms of geomorphology, soil environmental conditions and substrate availability for processes involved in carbon and nutrient cycling. In addition, fluctuating water tables lead to temporally changing redox conditions. In such systems, there are ideal conditions for the occurrence of hot spots and moments of nitrous oxide emissions, a potent greenhouse gas. The factors that govern the spatial heterogeneity and dynamics of N2O formation in floodplain soils and the surface efflux of this gas are not fully understood. A particular issue is the contribution of N2O formation in the subsoil to surface efflux. We studied this question in the floodplain of a restored section of the Thur river (NE Switzerland) which is characterized by a flashy flow regime. As a consequence, the floodplain soils are unsaturated most of the time. We showed earlier that saturation during flood pulses leads to short phases of generally anoxic conditions followed by a drying phase with anoxic conditions within aggregates and oxic conditions in larger soil pores. The latter conditions are conducive for spatially closely-coupled nitrification-denitrification and related hot moments of nitrous oxide formation. In a floodplain zone characterized by about one meter of young, sandy sediments, that are mostly covered by the tall grass Phalaris arundinacea, we measured at several time points before and after a small flood event N2O surface efflux with the closed-chamber method, and assessed N2O concentrations in the soil air at four different depths using gas-permeable tubings. In addition, we calculated the N2O diffusivity in the soil from Radon diffusivity. The latter was estimated in-situ from the recovery of Radon concentration in the gas-permeable tubings after purging with ambient air. All these data were then used to calculate net N2O production rates at different soil depths with the gradient method. In

  20. Effects of biosurfactant production by indigenous soil microorganisms on bioremediation of a co-contaminated soil in batch experiments

    Energy Technology Data Exchange (ETDEWEB)

    Jalali, F.; Mulligan, C.N. [Concordia Univ., Centre for Building Studies, Montreal, PQ (Canada). Dept. of Building, Civil and Environmental Engineering

    2007-07-01

    The challenge of remediating soils that are contaminated with both hydrocarbon compounds and metals was discussed, with particular reference to an in-situ bioremediation technique that was developed in the 1970s to deal with contaminated soils. The technique involves a two-stage process where water with added oxygen and nutrients is applied onto and injected into a contaminated area to stimulate the indigenous microbial populations in the soil. In addition to using organic pollutants as their carbon source, microorganisms can facilitate the removal of metals from the soil matrix and attenuate the toxicity of certain metals. Extraction wells placed downstream of the contaminated soils are used to remove and treat the water to eliminate any mobilized contaminants. This paper presented the results of batch experiments that evaluated the feasibility of biosurfactant production for the purpose of bioremediating a soil contaminated with aged petroleum hydrocarbons and heavy metals. The first phase of the study examined the growth of the native microbial population and the biodegradation of petroleum hydrocarbons, the production of biosurfactant and the mobilization of the total petroleum hydrocarbons (TPH) and metals into the aqueous phase. Biodegradation of petroleum hydrocarbons was observed in both soil and soil amended with nitrogen and phosphorous. However, the nutrient-amended soil had higher biodegradation of petroleum hydrocarbons, where 36 per cent of TPH was degraded by the end of the 50 day experiment, compared to 15 per cent for the non-amended soils. The concentration of biosurfactants in the same period increased 3 times their critical micelle concentration. It was concluded that biosurfactant production enhances the bioremediation of co-contaminated soils. 36 refs., 1 tab., 8 figs.

  1. Evaluation of some soil amendments plant productivity under saline conditions using nuclear techniques

    International Nuclear Information System (INIS)

    Aly, E.A.K.

    2004-01-01

    this study was carried out in Wadi Ras Sudr (south Saini government). this location was characterized as poor soil with high salinity (wasteland). in the same time it suffers from shortage of water resources. therefore, we aimed to utilize this soil as well as the saline ground water for introducing it into production systems. the reclamation of virgin poor soil need large efforts and much research, especially plant exposure to salinity which is rapidly followed by a decrease in growth rate. the use of natural organic sources as organic fertilizers improve the growth and yields of plants, and safe the environment from pollution . organic fertilizers (Of) such as green manure (G M) or poultry manure (P M) can be used as nutrient sources for good plant growth, where the soil amendments improve the physical, chemical and biological properties of the soil. economically, the yield improvement and nutrient supply will reflect the potential use of such organic materials. also , phosphorus and/or potassium supplementation separately or in combination with O F (G M and/or P M) improved the growth of both barley and wheat plants under such adverse condition of salinity using 15 N isotope dilution technique

  2. Effects of soil and water conservation on crop productivity: Evidences from Anjenie watershed, Ethiopia

    Science.gov (United States)

    Adgo, Enyew; Teshome, Akalu

    2014-05-01

    Widespread soil and water conservation activities have been implemented in many parts of eastern Africa to control soil erosion by water and improve land productivity for the last few decades. Following the 1974 severe drought, soil and water conservation became more important to Ethiopia and the approach shifted to watershed based land management initiatives since the 1980s. To capture long-term impacts of these initiatives, a study was conducted in Anjenie Watershed of Ethiopia, assessing fanya juu terraces and grass strips constructed in a pilot project in 1984, and which are still functional nearly 30 years later. Data were collected from government records, field observations and questionnaire surveys administered to 60 farmers. Half of the respondents had terraced farms in the watershed former project area (with terrace technology) and the rest were outside the terraced area. The crops assessed were teff, barley and maize. Cost-benefit analyses were used to determine the economic benefits with and without terraces, including gross and net profit values, returns on labour, water productivity and impacts on poverty. The results indicated that soil and water conservation had improved crop productivity. The average yield on terraced fields was 0.95 t ha-1 for teff (control 0.49), 1.86 t ha-1 for barley (control 0.61), and 1.73 t ha-1 for maize (control 0.77). The net benefit was significantly higher on terraced fields, recording US 20.9 (US -112 control) for teff, US 185 (US -41 control) for barley and US -34.5 (US - 101 control) ha-1 yr-1 for maize. The returns on family labour were 2.33 for barley, 1.01 for teff, and 0.739 US per person-day for maize grown on terraced plots, compared to US 0.44, 0.27 and 0.16 per person-day for plots without terraces, respectively. Using a discount rate of 10%, the average net present value (NPV) of barley production with terrace was found to be about US 1542 over a period of 50 years. In addition, the average financial

  3. Controls on surface soil drying rates observed by SMAP and simulated by the Noah land surface model

    Science.gov (United States)

    Shellito, Peter J.; Small, Eric E.; Livneh, Ben

    2018-03-01

    Drydown periods that follow precipitation events provide an opportunity to assess controls on soil evaporation on a continental scale. We use SMAP (Soil Moisture Active Passive) observations and Noah simulations from drydown periods to quantify the role of soil moisture, potential evaporation, vegetation cover, and soil texture on soil drying rates. Rates are determined using finite differences over intervals of 1 to 3 days. In the Noah model, the drying rates are a good approximation of direct soil evaporation rates, and our work suggests that SMAP-observed drying is also predominantly affected by direct soil evaporation. Data cover the domain of the North American Land Data Assimilation System Phase 2 and span the first 1.8 years of SMAP's operation. Drying of surface soil moisture observed by SMAP is faster than that simulated by Noah. SMAP drying is fastest when surface soil moisture levels are high, potential evaporation is high, and when vegetation cover is low. Soil texture plays a minor role in SMAP drying rates. Noah simulations show similar responses to soil moisture and potential evaporation, but vegetation has a minimal effect and soil texture has a much larger effect compared to SMAP. When drying rates are normalized by potential evaporation, SMAP observations and Noah simulations both show that increases in vegetation cover lead to decreases in evaporative efficiency from the surface soil. However, the magnitude of this effect simulated by Noah is much weaker than that determined from SMAP observations.

  4. Andropogon scoparius uptake of 45Ca and production from two contrasting soil types

    International Nuclear Information System (INIS)

    Waller, S.S.; Dodd, J.D.

    1976-01-01

    Total foliage production of Andropogon scoparius was greater on the Heiden-Hunt clay soil complex (Udic chromusterts and pellusterts) than on he Tabor fine sandy loam (Udertic paleustalfs). Foliage production on both soil types increased as clipping frequency decreased. Foliage production and 45 C uptake exhibited a positive relationship with precipitation during the growing season. Total uptake and concentration were greater in the sand-grown clones than in the clay-grown clones. Foliage concentration was inversely related to stable soil Ca and reflected the ratio of radioactive to stable Ca in the soil. However, uptake at the end of the growing season was less than 0.20% of that applied on either soil type. Increased clipping frequency increased foliage 45 Ca concentration on both soil types

  5. Initial water repellency affected organic matter depletion rates of manure amended soils in Sri Lanka

    Directory of Open Access Journals (Sweden)

    Leelamanie D.A.L.

    2014-12-01

    Full Text Available The wetting rate of soil is a measure of water repellency, which is a property of soils that prevents water from wetting or penetrating into dry soil. The objective of the present research was to examine the initial water repellency of organic manure amended soil, and its relation to the soil organic matter (SOM depletion rates in the laboratory. Soil collected from the Wilpita natural forest, Sri Lanka, was mixed with organic manure to prepare soil samples with 0, 5, 10, 25, and 50% organic manure contents. Locally available cattle manure (CM, goat manure (GM, and Casuarina equisetifolia leaves (CE were used as the organic manure amendments. Organic matter content of soils was measured in 1, 3, 7, 14, and 30 days intervals under the laboratory conditions with 74±5% relative humidity at 28±1°C. Initial water repellency of soil samples was measured as the wetting rates using the water drop penetration time (WDPT test. Initial water repellency increased with increasing SOM content showing higher increasing rate for hydrophobic CE amended samples compared with those amended with CM and GM. The relation between water repellency and SOM content was considered to be governed by the original hydrophobicities of added manures. The SOM contents of all the soil samples decreased with the time to reach almost steady level at about 30 d. The initial SOM depletion rates were negatively related with the initial water repellency. However, all the CE amended samples initially showed prominent low SOM depletion rates, which were not significantly differed with the amended manure content or the difference in initial water repellency. It is explicable that the original hydrophobicity of the manure as well has a potentially important effect on initiation of SOM decomposition. In contrast, the overall SOM depletion rate can be attributed to the initial water repellency of the manure amended sample, however, not to the original hydrophobicity of the amended manure

  6. Mobility of gamma-emitting fission products in typical black and laterite soils

    International Nuclear Information System (INIS)

    D'Souza, T.J.; Mistry, K.B.

    1981-01-01

    Studies on the movement of the gamma-emitting fission products 106 Ru, 125 Sb, 137 Cs and 144 Ce, surface deposited on columns of the black and laterite soils revealed that the mobility of these nuclides in the two soils depended mainly on the ionic form of the nuclide, soil reaction and predominant clay mineral type in the soil. Results showed a rapid breakthrough of 106 Ru in the black soil and considerable migration to the lower layers in the laterite soil on leaching with rain water, or moderately high calcium or sodium irrigation waters. While near complete fixation of 144 Ce and 137 Cs in the top contaminated layer of both soils was observed, a slight movement of 125 Sb only in the black soil was noticed. Incorporation of organic matter had no effects on the movement of fission products in both soil types, whereas ethylenediaminetraacetic acid (EDTA) induced variable movement of the different radionuclides in the two soil types. (author)

  7. Soil development rates from an optically stimulated luminescence-dated beach ridge sequence in Northern Jutland, Denmark

    DEFF Research Database (Denmark)

    Nielsen, Asger Habekost; Elberling, Bo; Pejrup, Morten

    2010-01-01

    Rates of podzolic soil development in sandy, temperate soils were quantified based on 14 soil pedons with five substrata from a beach ridge chronosequence near Jerup, Northern Denmark (578N). Soil pH, organic carbon (C) as well as extractable iron (Fe) and aluminium (Al) were measured. The age...... of 22911 yr. Acidification rates during the first 200 yr were1.9pH units per 100 yr in the A horizons and C-sequestration rates were25 g C m2 yr1 (excluding litter accumulation). After1500 yr, the mineral soil C stocks stabilised around 13.092.0 kg C m2. Translocation rates of Al into B horizons were0.3 kg...

  8. Absorption of gamma-emitting fission products and activation products by rice under flooded and unflooded conditions from two tropical soils

    Energy Technology Data Exchange (ETDEWEB)

    D' Souza, T J; Mistry, K B [Bhabha Atomic Research Centre, Bombay (India). Biology and Agriculture Div.

    1980-01-01

    The absorption of gamma-emitting fission products /sup 106/Ru, /sup 125/Sb, /sup 137/Cs and /sup 144/Ce and activation products /sup 59/Fe, /sup 58/Co, /sup 54/Mn and /sup 65/Zn by rice plants grown on two contrasting tropical soils, namely, a blak soil (pellustert) and a laterite (oxisol), and the effects of flooding were studied under controlled conditions. Results indicated greater uptake of /sup 106/Ru and /sup 125/Sb from the black soil than from the laterite. In contrast, the uptake of /sup 144/Ce and /sup 137/Cs was greater in the laterite than in the black soil. Flooding treatment enhanced the uptake of all these fission products by rice plants in the laterite soil whereas this effect was observed only for /sup 125/Sb and /sup 137/Cs in the black soil. The plant uptake of activation products from the two soil types showed maximum accumulation of /sup 65/Zn followed by /sup 54/Mn, /sup 59/Fe and /sup 58/Co in both soil types. Besides, uptake of these nuclides was greater from the laterite soil than from the black soil. Flooding treatment for rice while showing a reduction of /sup 59/Fe uptake showed an increase in plant uptake of /sup 58/Co, /sup 54/Mn and /sup 65/Zn in both soil types.

  9. Pollution impact of cement production on air, soil and water in a ...

    African Journals Online (AJOL)

    Pollution impact of cement production on air, soil and water in a production location in Nigeria. ... Journal of Science and Technology (Ghana) ... location from the pollution source, which served as control for particulate and soil sampling.

  10. Soil quality assessment of rice production systems in South of Brazil

    OpenAIRE

    Rodrigues de Lima, A.C.; Hoogmoed, W.B.; Brussaard, L.

    2006-01-01

    Soil quality, as a measure of the soil capacity to function, can be quantified by indicators based on physical, chemical and biological properties. Maintaining soil quality at a desirable level in the rice cropping system is a very complex issue due to the nature of the production systems used. In the state of Rio Grande do Sul, Brazil, rice production is one of the most important agricultural activities in the region. The study presented here was conducted with the following objectives: (i) ...

  11. Effectiveness of two contrasting mulching rates to reduce post-fire soil and organic matter losses

    Science.gov (United States)

    Silva, Flavio; Prats, Sergio; Vieira, Diana; Puga, João; Lopes, Rita; Gonzaléz-Pelayo, Oscar; Caetano, Ana; Campos, Isabel; Keizer, Jacob

    2017-04-01

    Wildfire-affected soils can reveal strong responses in runoff generation and associated soil (fertility) losses, thereby constituting a major threat to the typically shallow and poor forest soils of the Portuguese mountain areas. Mulching with logging residues from these forests has proven to provide a protective soil cover that is highly effective in reducing post-fire runoff and especially erosion (Prats et al., 2012, 2014, 2016a, 2016b). However, these past experiments have all applied comparatively large amounts of forest residues, in the order of 10 Mg ha-1, so that the relationship between application rate and effectiveness is still poorly known. Such relationship would nonetheless be of crucial importance for the employment of forest residue mulching in practice, as one of the possible emergency stabilization measures to be contemplated in post-fire land management of a recently-burned area. Further research gaps that exist in relation to post-fire forest residue mulching include its effectiveness in reducing soil fertility losses (C, N, P; Ferreira et al., 2016a, 2016b) and in minimizing export of contaminants (especially PAHs and metals; Campos et al., 2016), and its (secondary) impacts on soil biological activity and diversity (Puga et al., 2016) and on forest productivity (including through the addition of organic matter to the soil surface, partially replacing the burned litter layer; Prats et al. 2016b). In the framework of the EU-project RECARE, the effectiveness of two contrasting mulching rates with forest logging residues has been tested following a wildfire that on August 9th - 10th 2015 consumed some 715 ha of eucalypt plantations in the Semide municipality, central Portugal. Commercially-available logging residues (chopped bark and twigs) from eucalypt plantations were purchased, transported to the study site and applied to six out of nine 16 m2 erosion bounded plots that had been installed in a burned eucalypt plantation using a randomized

  12. Establishment of the relationship between 137Cs loss and soil erosion rates

    International Nuclear Information System (INIS)

    Phan Son Hai

    2003-01-01

    The key stages involved in the use of 137 Cs in soil erosion assessment is presented. The method have been successfully applied in pilot scale. These main stages can be summarized as follows: 1/ selection of reference sites next to the study site and establishment of a reference fallout inventory for the study site; 2/measurement of the current spatial distribution of 137 Cs inventory; 3/ evaluation of the pattern of 137 Cs redistribution at the study site; 4/ development of a calibration relationship between 137 CS loss and gain and rate of soil erosion; 5/ estimation of soil redistribution rates using the calibration relationship. (PSH)

  13. A simplified 137Cs transport model for estimating erosion rates in undisturbed soil

    International Nuclear Information System (INIS)

    Zhang Xinbao; Long Yi; He Xiubin; Fu Jiexiong; Zhang Yunqi

    2008-01-01

    137 Cs is an artificial radionuclide with a half-life of 30.12 years which released into the environment as a result of atmospheric testing of thermo-nuclear weapons primarily during the period of 1950s-1970s with the maximum rate of 137 Cs fallout from atmosphere in 1963. 137 Cs fallout is strongly and rapidly adsorbed by fine particles in the surface horizons of the soil, when it falls down on the ground mostly with precipitation. Its subsequent redistribution is associated with movements of the soil or sediment particles. The 137 Cs nuclide tracing technique has been used for assessment of soil losses for both undisturbed and cultivated soils. For undisturbed soils, a simple profile-shape model was developed in 1990 to describe the 137 Cs depth distribution in profile, where the maximum 137 Cs occurs in the surface horizon and it exponentially decreases with depth. The model implied that the total 137 Cs fallout amount deposited on the earth surface in 1963 and the 137 Cs profile shape has not changed with time. The model has been widely used for assessment of soil losses on undisturbed land. However, temporal variations of 137 Cs depth distribution in undisturbed soils after its deposition on the ground due to downward transport processes are not considered in the previous simple profile-shape model. Thus, the soil losses are overestimated by the model. On the base of the erosion assessment model developed by Walling, D.E., He, Q. [1999. Improved models for estimating soil erosion rates from cesium-137 measurements. Journal of Environmental Quality 28, 611-622], we discuss the 137 Cs transport process in the eroded soil profile and make some simplification to the model, develop a method to estimate the soil erosion rate more expediently. To compare the soil erosion rates calculated by the simple profile-shape model and the simple transport model, the soil losses related to different 137 Cs loss proportions of the reference inventory at the Kaixian site of the

  14. Soil microbial C:N ratio is a robust indicator of soil productivity for paddy fields

    Science.gov (United States)

    Li, Yong; Wu, Jinshui; Shen, Jianlin; Liu, Shoulong; Wang, Cong; Chen, Dan; Huang, Tieping; Zhang, Jiabao

    2016-10-01

    Maintaining good soil productivity in rice paddies is important for global food security. Numerous methods have been developed to evaluate paddy soil productivity (PSP), most based on soil physiochemical properties and relatively few on biological indices. Here, we used a long-term dataset from experiments on paddy fields at eight county sites and a short-term dataset from a single field experiment in southern China, and aimed at quantifying relationships between PSP and the ratios of carbon (C) to nutrients (N and P) in soil microbial biomass (SMB). In the long-term dataset, SMB variables generally showed stronger correlations with the relative PSP (rPSP) compared to soil chemical properties. Both correlation and variation partitioning analyses suggested that SMB N, P and C:N ratio were good predictors of rPSP. In the short-term dataset, we found a significant, negative correlation of annual rice yield with SMB C:N (r = -0.99), confirming SMB C:N as a robust indicator for PSP. In treatments of the short-term experiment, soil amendment with biochar lowered SMB C:N and improved PSP, while incorporation of rice straw increased SMB C:N and reduced PSP. We conclude that SMB C:N ratio does not only indicate PSP but also helps to identify management practices that improve PSP.

  15. Thoron (RN-220) interference in the determination of RN-222 exhalation rate of soils

    Energy Technology Data Exchange (ETDEWEB)

    Amaral, Déric S.; Farias, Emerson E.G.; Santos, Mariana L.O.; Silva, Karolayne E.M.; Hazin, Clovis A.; França, Elvis J., E-mail: emersonemiliano@yahoo.com [Centro Regional de Ciências Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil); Souza Neto, João A., E-mail: adauto@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Departamento de Geologia

    2017-07-01

    The transport of Rn-222 from the soil to the atmosphere known as exhalation is influenced by meteorological conditions and soil geophysical parameters. In closed and poorly ventilated rooms, this radioactive gas can reach high activity concentrations, in which the energy of alpha particles released by this radionuclide and its progeny is the second leading cause of lung cancer. Soil exhalation rate is an important parameter for assessing human health risks associated with radon. For radon determination using an exhalation chamber, an ionization chamber detector is used to count the electrical pulses generated by the interaction between the alpha particles produced by Rn-222 and its progeny and the air inside the chamber. In this work, the interference of thoron (Rn-220) in the determination of soil exhalation rate of Rn-222 was studied. For this, the RadonBOX exhalation chamber and the AlphaGuard ionization chamber detector were utilized for analyzing the same soil during two hours on different days under similar meteorological conditions. From zero up to approximately 2,400 s, the radon activity concentrations decreased. After 40 minutes, the radon concentrations started to increase, thereby allowing the calculation of soil exhalation rate. This initial decreasing could be explained by a high Rn-220 than Rn-222 presence in the soil, in which, because of its short half-life, after 40 minutes, most thoron present in the chamber has undergone so that the main alpha emitter become Rn-222. In order to confirm this, Rn-220 activity was estimated by the Ra-228 concentration in the soil determined after 30 days using High Resolution Gamma-Ray Spectrometry with HPGe detectors. Therefore, the thoron interference in the determination of soil radon exhalation rate was considered negligible after 40 minutes of measurement time for the analyzed soil. (author)

  16. Sustainability of US Organic Beef and Dairy Production Systems: Soil, Plant and Cattle Interactions

    Directory of Open Access Journals (Sweden)

    Kathy J. Soder

    2013-07-01

    Full Text Available In 2010, the National Organic Program implemented a rule for the US stating that pasture must be a significant source of feed in organic ruminant systems. This article will focus on how the pasture rule has impacted the management, economics and nutritional value of products derived from organic ruminant systems and the interactions of grazing cattle with pasture forages and soils. The use of synthetic fertilizers is prohibited in organic systems; therefore, producers must rely on animal manures, compost and cover crops to increase and maintain soil nitrogen content. Rotational and strip grazing are two of the most common grazing management practices utilized in grazing ruminant production systems; however, these practices are not exclusive to organic livestock producers. For dairy cattle, grazing reduces foot and leg problems common in confinement systems, but lowers milk production and exposes cows to parasites that can be difficult to treat without pharmaceuticals. Organic beef cattle may still be finished in feedlots for no more than 120 days in the US, but without growth hormones and antibiotics, gains may be reduced and illnesses increased. Grazing reduces the use of environmentally and economically costly concentrate feeds and recycles nutrients back to the soil efficiently, but lowers the rate of beef liveweight gain. Increased use of pasture can be economically, environmentally and socially sustainable if forage use efficiency is high and US consumers continue to pay a premium for organic beef and dairy products.

  17. CRADA Carbon Sequestration in Soils and Commercial Products

    Energy Technology Data Exchange (ETDEWEB)

    Jacobs, G.K.

    2002-01-31

    ORNL, through The Consortium for Research on Enhancing Carbon Sequestration in Terrestrial Ecosystems (CSiTE), collaborated with The Village Botanica, Inc. (VB) on a project investigating carbon sequestration in soils and commercial products from a new sustainable crop developed from perennial Hibiscus spp. Over 500 pre-treated samples were analyzed for soil carbon content. ORNL helped design a sampling scheme for soils during the planting phase of the project. Samples were collected and prepared by VB and analyzed for carbon content by ORNL. The project did not progress to a Phase II proposal because VB declined to prepare the required proposal.

  18. Rate of loss of simazine, terbuthylazine, isoproturon, and methabenzthiazuron during soil solarization.

    Science.gov (United States)

    Navarro, Simón; Bermejo, Salvador; Vela, Nuria; Hernández, Joaquín

    2009-07-22

    This paper reports the use of solar heating by polyethylene mulching for decontamination of a silty clay-loam soil polluted with herbicides. Soil solarization, a natural and hydrothermal method commonly used for disinfesting soils, was tested during the summer season on a Hipercalcic Calcisol located in Murcia (southeast Spain) for dissipation of s-triazine (simazine and terbuthylazine) and phenylurea (isoproturon and methabenzthiazuron) herbicides using low-density (LD) and high-density (HD) polyethylene (PE) film as a cover. A well-established influence of the film was observed on the dissipation of all herbicides from the soil, although the density (0.92-0.95 g/cm(3)) of the film used (LDPE and HDPE) was not significant in terms of the rate of loss. In all cases, a quick depletion during the first 2 weeks was observed, mainly for terbuthylazine. The first-order model satisfactorily explained the dissipation process, but the Hoerl and biexponential equations were more appropriate, mainly for simazine, isoproturon, and methabenzthiazuron. In all cases, herbicides disappeared at faster rates in solarized soils (DT(50) = 4-29 days) than in nonmulched soils (DT(50) = 11-35 days), especially for terbuthylazine and isoproturon.

  19. Chlorination and dechlorination rates in a forest soil — A combined modelling and experimental approach

    Energy Technology Data Exchange (ETDEWEB)

    Montelius, Malin, E-mail: malin.montelius@liu.se [Department of Thematic Studies — Environmental Change, Linköping University, 581 83 Linköping (Sweden); Svensson, Teresia [Department of Thematic Studies — Environmental Change, Linköping University, 581 83 Linköping (Sweden); Lourino-Cabana, Beatriz [EDF, Laboratoire National d' Hydraulique et Environnement, 78401 Chatou (France); Thiry, Yves [Andra, Research and Development Division, Parc de la Croix Blanche, 1/7 rue Jean Monnet, 92298 Châtenay-Malabry Cedex (France); Bastviken, David [Department of Thematic Studies — Environmental Change, Linköping University, 581 83 Linköping (Sweden)

    2016-06-01

    Much of the total pool of chlorine (Cl) in soil consists of naturally produced organic chlorine (Cl{sub org}). The chlorination of bulk organic matter at substantial rates has been experimentally confirmed in various soil types. The subsequent fates of Cl{sub org} are important for ecosystem Cl cycling and residence times. As most previous research into dechlorination in soils has examined either single substances or specific groups of compounds, we lack information about overall bulk dechlorination rates. Here we assessed bulk organic matter chlorination and dechlorination rates in coniferous forest soil based on a radiotracer experiment conducted under various environmental conditions (additional water, labile organic matter, and ammonium nitrate). Experiment results were used to develop a model to estimate specific chlorination (i.e., fraction of Cl{sup −} transformed to Cl{sub org} per time unit) and specific dechlorination (i.e., fraction of Cl{sub org} transformed to Cl{sup −} per time unit) rates. The results indicate that chlorination and dechlorination occurred simultaneously under all tested environmental conditions. Specific chlorination rates ranged from 0.0005 to 0.01 d{sup −1} and were hampered by nitrogen fertilization but were otherwise similar among the treatments. Specific dechlorination rates were 0.01–0.03 d{sup −1} and were similar among all treatments. This study finds that soil Cl{sub org} levels result from a dynamic equilibrium between the chlorination and rapid dechlorination of some Cl{sub org} compounds, while another Cl{sub org} pool is dechlorinated more slowly. Altogether, this study demonstrates a highly active Cl cycling in soils. - Highlights: • Chlorination and dechlorination rates in soil were revealed by a radiotracer method. • Chlorination was hampered by nitrogen addition. • Both Cl{sup −} and many Cl{sub org} compounds are highly reactive in soils. • Some formed Cl{sub org} seem to be refractory.

  20. Impact of petroleum products on soil composition and physical-chemical properties

    Science.gov (United States)

    Brakorenko, N. N.; Korotchenko, T. V.

    2016-03-01

    The article describes the grain-size distribution, physical and mechanical properties, swelling and specific electrical resistivity of soils before and after the contact with petroleum products. The changes in mechanical properties of soils contaminated with petroleum products have been stated. It leads to the increase in compressibility values, decline in internal friction angle and cohesion.

  1. Impact of petroleum products on soil composition and physical-chemical properties

    OpenAIRE

    Brakorenko, Nataliya Nikolaevna; Korotchenko, Tatiana Valerievna

    2016-01-01

    The article describes the grain-size distribution, physical and mechanical properties, swelling and specific electrical resistivity of soils before and after the contact with petroleum products. The changes in mechanical properties of soils contaminated with petroleum products have been stated. It leads to the increase in compressibility values, decline in internal friction angle and cohesion.

  2. The Impact of Soil Sampling Errors on Variable Rate Fertilization

    Energy Technology Data Exchange (ETDEWEB)

    R. L. Hoskinson; R C. Rope; L G. Blackwood; R D. Lee; R K. Fink

    2004-07-01

    Variable rate fertilization of an agricultural field is done taking into account spatial variability in the soil’s characteristics. Most often, spatial variability in the soil’s fertility is the primary characteristic used to determine the differences in fertilizers applied from one point to the next. For several years the Idaho National Engineering and Environmental Laboratory (INEEL) has been developing a Decision Support System for Agriculture (DSS4Ag) to determine the economically optimum recipe of various fertilizers to apply at each site in a field, based on existing soil fertility at the site, predicted yield of the crop that would result (and a predicted harvest-time market price), and the current costs and compositions of the fertilizers to be applied. Typically, soil is sampled at selected points within a field, the soil samples are analyzed in a lab, and the lab-measured soil fertility of the point samples is used for spatial interpolation, in some statistical manner, to determine the soil fertility at all other points in the field. Then a decision tool determines the fertilizers to apply at each point. Our research was conducted to measure the impact on the variable rate fertilization recipe caused by variability in the measurement of the soil’s fertility at the sampling points. The variability could be laboratory analytical errors or errors from variation in the sample collection method. The results show that for many of the fertility parameters, laboratory measurement error variance exceeds the estimated variability of the fertility measure across grid locations. These errors resulted in DSS4Ag fertilizer recipe recommended application rates that differed by up to 138 pounds of urea per acre, with half the field differing by more than 57 pounds of urea per acre. For potash the difference in application rate was up to 895 pounds per acre and over half the field differed by more than 242 pounds of potash per acre. Urea and potash differences

  3. Environmental impact of petroleum products in the soil. Part II: Petroleum products composition and key properties

    International Nuclear Information System (INIS)

    Zerlia, T.

    2001-01-01

    The fate of petroleum hydrocarbons in the soil depends on the chemical-physic properties of each hydrocarbon, as well as on the soil characteristics. The mean composition of various petroleum products, the key chemical compounds and their characteristics are focused in order to outline the environmental behaviour of petroleum hydrocarbons in the soil [it

  4. Modeling nitrous oxide production and reduction in soil through explicit representation of denitrification enzyme kinetics.

    Science.gov (United States)

    Zheng, Jianqiu; Doskey, Paul V

    2015-02-17

    An enzyme-explicit denitrification model with representations for pre- and de novo synthesized enzymes was developed to improve predictions of nitrous oxide (N2O) accumulations in soil and emissions from the surface. The metabolic model of denitrification is based on dual-substrate utilization and Monod growth kinetics. Enzyme synthesis/activation was incorporated into each sequential reduction step of denitrification to regulate dynamics of the denitrifier population and the active enzyme pool, which controlled the rate function. Parameterizations were developed from observations of the dynamics of N2O production and reduction in soil incubation experiments. The model successfully reproduced the dynamics of N2O and N2 accumulation in the incubations and revealed an important regulatory effect of denitrification enzyme kinetics on the accumulation of denitrification products. Pre-synthesized denitrification enzymes contributed 20, 13, 43, and 62% of N2O that accumulated in 48 h incubations of soil collected from depths of 0-5, 5-10, 10-15, and 15-25 cm, respectively. An enzyme activity function (E) was defined to estimate the relative concentration of active enzymes and variation in response to environmental conditions. The value of E allows for activities of pre-synthesized denitrification enzymes to be differentiated from de novo synthesized enzymes. Incorporating explicit representations of denitrification enzyme kinetics into biogeochemical models is a promising approach for accurately simulating dynamics of the production and reduction of N2O in soils.

  5. No apparent costs for facultative antibiotic production by the soil bacterium Pseudomonas fluorescens Pf0-1.

    Science.gov (United States)

    Garbeva, Paolina; Tyc, Olaf; Remus-Emsermann, Mitja N P; van der Wal, Annemieke; Vos, Michiel; Silby, Mark; de Boer, Wietse

    2011-01-01

    Many soil-inhabiting bacteria are known to produce secondary metabolites that can suppress microorganisms competing for the same resources. The production of antimicrobial compounds is expected to incur fitness costs for the producing bacteria. Such costs form the basis for models on the co-existence of antibiotic-producing and non-antibiotic producing strains. However, so far studies quantifying the costs of antibiotic production by bacteria are scarce. The current study reports on possible costs, for antibiotic production by Pseudomonas fluorescens Pf0-1, a soil bacterium that is induced to produce a broad-spectrum antibiotic when it is confronted with non-related bacterial competitors or supernatants of their cultures. We measured the possible cost of antibiotic production for Pseudomonas fluorescens Pf0-1 by monitoring changes in growth rate with and without induction of antibiotic production by supernatant of a bacterial competitor, namely Pedobacter sp.. Experiments were performed in liquid as well as on semi-solid media under nutrient-limited conditions that are expected to most clearly reveal fitness costs. Our results did not reveal any significant costs for production of antibiotics by Pseudomonas fluorescens Pf0-1. Comparison of growth rates of the antibiotic-producing wild-type cells with those of non-antibiotic producing mutants did not reveal costs of antibiotic production either. Based on our findings we propose that the facultative production of antibiotics might not be selected to mitigate metabolic costs, but instead might be advantageous because it limits the risk of competitors evolving resistance, or even the risk of competitors feeding on the compounds produced.

  6. Biomass production on saline-alkaline soils

    Energy Technology Data Exchange (ETDEWEB)

    Chaturvedi, A.N.

    1985-01-01

    In a trial of twelve tree species (both nitrogen fixing and non-fixing) for fuel plantations on saline-alkaline soil derived from Gangetic alluvium silty clay, Leucaena leucocephala failed completely after showing rapid growth for six months. Results for other species at age two showed that Prosopis juliflora had the best productivity.

  7. Removal of fission products from waste solutions using 16 different soil samples

    International Nuclear Information System (INIS)

    Bangash, M.A.; Hanif, J.

    1997-01-01

    Most of the nuclear sites use pits in the surrounding soils for the storage/disposal of low active waste (LAW) solutions. The characteristics of the soil if not suitable for the fixation or adsorption of the radioactive nuclides, may cause migration of these nuclides to hydrosphere. The phenomenon has the risk of radio toxic pollution for the living bodies therefore minerals composing the soil and their adsorption properties need to be investigated. For this purpose 16 different soil samples were collected from all over Pakistan. Mineralogical composition of the soils was determined by X-ray diffraction analysis. It was found that most of the samples contained clay minerals, illite, kaolinite and montmorillonite. Studies for the removal of fission products like, /sup 137/Cs. /sup 60/Sr and activation product /sup 60/CO from solution were carried out on these samples. The sorption experiments were performed by batch technique using radioactive as tracers. Distribution co-efficient were determined by mixing he element solution at pH 3 with the soil at soil solution ratios of 1 to 20. It is revealed from the experimental data that efficient removal of fission products from solutions is achieved by soil samples containing clay mineral montmorillonite, followed by little and kaolinite. These soils thus can be effectively used for the disposal of low level radioactive waste solutions without causing any environmental hazard. (author)

  8. Fuzzy production planning models for an unreliable production system with fuzzy production rate and stochastic/fuzzy demand rate

    Directory of Open Access Journals (Sweden)

    K. A. Halim

    2011-01-01

    Full Text Available In this article, we consider a single-unit unreliable production system which produces a single item. During a production run, the production process may shift from the in-control state to the out-of-control state at any random time when it produces some defective items. The defective item production rate is assumed to be imprecise and is characterized by a trapezoidal fuzzy number. The production rate is proportional to the demand rate where the proportionality constant is taken to be a fuzzy number. Two production planning models are developed on the basis of fuzzy and stochastic demand patterns. The expected cost per unit time in the fuzzy sense is derived in each model and defuzzified by using the graded mean integration representation method. Numerical examples are provided to illustrate the optimal results of the proposed fuzzy models.

  9. Effect of soil metal contamination on glyphosate mineralization: role of zinc in the mineralization rates of two copper-spiked mineral soils.

    Science.gov (United States)

    Kim, Bojeong; Kim, Young Sik; Kim, Bo Min; Hay, Anthony G; McBride, Murray B

    2011-03-01

    A systematic investigation into lowered degradation rates of glyphosate in metal-contaminated soils was performed by measuring mineralization of [(14)C]glyphosate to (14)CO(2) in two mineral soils that had been spiked with Cu and/or Zn at various loadings. Cumulative (14)CO(2) release was estimated to be approximately 6% or less of the amount of [(14)C]glyphosate originally added in both soils over an 80-d incubation. For all but the highest Cu treatments (400 mg kg(-1)) in the coarse-textured Arkport soil, mineralization began without a lag phase and declined over time. No inhibition of mineralization was observed for Zn up to 400 mg kg(-1) in either soil, suggesting differential sensitivity of glyphosate mineralization to the types of metal and soil. Interestingly, Zn appeared to alleviate high-Cu inhibition of mineralization in the Arkport soil. The protective role of Zn against Cu toxicity was also observed in the pure culture study with Pseudomonas aeruginosa, suggesting that increased mineralization rates in high Cu soil with Zn additions might have been due to alleviation of cellular toxicity by Zn rather than a mineralization specific mechanism. Extensive use of glyphosate combined with its reduced degradation in Cu-contaminated, coarse-textured soils may increase glyphosate persistence in soil and consequently facilitate Cu and glyphosate mobilization in the soil environment. Copyright © 2010 SETAC.

  10. Extreme soil erosion rates in citrus slope plantations and control strategies. A literature review

    Science.gov (United States)

    Cerdà, Artemi; Ángel González Peñaloza, Félix; Pereira, Paulo; Reyes Ruiz Gallardo, José; García Orenes, Fuensanta; Burguet, María

    2013-04-01

    Soil Erosion is a natural process that shapes the Earth. Due to the impact of agriculture, soil erosion rates increase, landforms show gullies and rills, and soils are depleted. In the Mediterranean, wheat, olive and vineyards were the main agriculture products, but new plantations are being found in sloping terrain due to the drip-irrigation. This new strategy results in the removal of the traditional terraces in order to make suitable for mechanization the agriculture plantation. Citrus is a clear example of the impact of the new chemical agriculture with a high investment in herbicides, pesticides, mechanisation, land levelling and drip computer controlled irrigation systems. The new plantation of citrus orchards is found in the Mediterranean, but also in California, Florida, China and Brazil. Chile, Argentina, and South Africa are other producers that are moving to an industrial production of citrus. This paper shows how the citrus plantations are found as one of the most aggressive plantation due to the increase in soil erosion, and how we can apply successful control strategies. The research into the high erosion rates of citrus orchard built on the slopes are mainly found in China (Wu et al., 1997; Xu et al., 2010; Wang et al., 2011; Wu et al., 2011; Liu et al., 2011; Lü et al., 2011; Xu et al., 2012) and in the Mediterranean (Cerdà and Jurgensen, 2008; 2009; Cerdà et al., 2009a; 2009b; Cerdà et al., 2011; 2012) Most of the research done devoted to the measurements of the soil losses but also some research is done related to the soil properties (Lu et al., 1997; Lü et al., 2012; Xu et al., 2012) and the impact of cover crops to reduce the soil losses (Lavigne et al., 2012; Le Bellec et al., 2012) and the use of residues such as dried citrus peel in order to reduce the soil losses. There are 116 million tonnes of citrus produced yearly, and this affects a large surface of the best land. The citrus orchards are moving from flood irrigated to drip

  11. Nonlinear estimation of weathering rate parameters for uranium in surface soil near a nuclear facility

    International Nuclear Information System (INIS)

    Killough, G.G.; Rope, S.K.; Shleien, B.; Voilleque, P.G.

    1999-01-01

    A dynamic mass-balance model has been calibrated by a nonlinear parameter estimation method, using time-series measurements of uranium in surface soil near the former Feed Materials Production Center (FMPC) near Fernald, Ohio, USA. The time-series data, taken at six locations near the site boundary since 1971, show a statistically significant downtrend of above-background uranium concentration in surface soil for all six locations. The dynamic model is based on first-order kinetics in a surface-soil compartment 10 cm in depth. Median estimates of weathering rate coefficients for insoluble uranium in this soil compartment range from about 0.065-0.14 year -1 , corresponding to mean transit times of about 7-15 years, depending on the location sampled. The model, calibrated by methods similar to those discussed in this paper, has been used to simulate surface soil kinetics of uranium for a dose reconstruction study. It was also applied, along with other data, to make confirmatory estimates of airborne releases of uranium from the FMPC between 1951 and 1988. Two soil-column models (one diffusive and one advective, the latter similar to a catenary first-order kinetic box model) were calibrated to profile data taken at one of the six locations in 1976. The temporal predictions of the advective model approximate the trend of the time series data for that location. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)

  12. A New Approach in Downscaling Microwave Soil Moisture Product using Machine Learning

    Science.gov (United States)

    Abbaszadeh, Peyman; Yan, Hongxiang; Moradkhani, Hamid

    2016-04-01

    Understating the soil moisture pattern has significant impact on flood modeling, drought monitoring, and irrigation management. Although satellite retrievals can provide an unprecedented spatial and temporal resolution of soil moisture at a global-scale, their soil moisture products (with a spatial resolution of 25-50 km) are inadequate for regional study, where a resolution of 1-10 km is needed. In this study, a downscaling approach using Genetic Programming (GP), a specialized version of Genetic Algorithm (GA), is proposed to improve the spatial resolution of satellite soil moisture products. The GP approach was applied over a test watershed in United States using the coarse resolution satellite data (25 km) from Advanced Microwave Scanning Radiometer - EOS (AMSR-E) soil moisture products, the fine resolution data (1 km) from Moderate Resolution Imaging Spectroradiometer (MODIS) vegetation index, and ground based data including land surface temperature, vegetation and other potential physical variables. The results indicated the great potential of this approach to derive the fine resolution soil moisture information applicable for data assimilation and other regional studies.

  13. Crop production in salt affected soils: A biological approach

    Energy Technology Data Exchange (ETDEWEB)

    Malik, K A [National Inst. for Biotechnology and Genetic Engineering (NIBGE), Faisalabad (Pakistan)

    1995-01-01

    Plant are susceptible to various stresses, affecting growth productivity. Among the abiotic stresses, soil salinity is most significant and prevalent in both developed and developing countries. As a result, good productive lands are being desertified at a very high pace. To combat this problem various approaches involving soil management and drainage are underway but with little success. It seems that a durable solution of the salinity and water-logging problems may take a long time and we may have to learn to live with salinity and to find other ways to utilize the affected lands fruitfully. A possible approach could be to tailor plants to suit the deleterious environment. The saline-sodic soils have excess of sodium, are impermeable, have little or no organic matter and are biologically almost dead. Introduction of a salt tolerant crop will provide a green cover and will improve the environment for biological activity, increase organic matter and will improve the soil fertility. The plant growth will result in higher carbon dioxide levels, and would thus create acidic conditions in the soil which would dissolve the insoluble calcium carbonate and will help exchange sodium with calcium ions on the soil complex. The biomass produced could be used directly as fodder or by the use of biotechnological and other procedures it could be converted into other value added products. However, in order to tailor plants to suit these deleterious environments, acquisition of better understanding of the biochemical and genetic aspects of salt tolerance at the cellular/molecular level is essential. For this purpose model systems have been carefully selected to carry out fundamental basic research that elucidates and identifies the major factors that confer salt tolerance in a living system. With the development of modern biotechnological methods it is now possible to introduce any foreign genetic material known to confer salt tolerance into crop plants. (Abstract Truncated)

  14. Effect of phosphate rate on the L-value of two soils from Bahia State, Brazil

    International Nuclear Information System (INIS)

    Cotrim Duete, Robson Rui; Alvarez Villanueva, Felipe Carlos; Muraoka, Takashi; Abreu Junior, Cassio Hamilton

    1999-01-01

    The determination of L value in low phosphate content soils has presented contradictory results in the literature. In order to evaluate the effect of P rates on L value of two representative soils of Bahia State, Brazil, an experiment was carried out in green house of CENA, USP in Piracicaba. The experiment consisted of two soils (calcareous Red-yellow latosol ''LVc'' and distrofic Red-yellow latosol ''LVd'', collected from Irec and Ribeira do Pombal, respectively) and three P rates (0; 28; and 140 kg P ha -1 ) as triple superphosphate and carried out in plastic pot with 2.5 kg of soil, using corn (Zea mays L.) ''Catetinho Sabugo Roxo'' cultivar as the test plant. The 32 P was applied as KH2PO4 solution, 3.7MBq/pot. The plants were collected 45 days after emergence, dried, weighed, ground and analised for total P content and 32 P radioactivity. The increasing fertilizer P rate increased the nutrient derived from the soil and consequentely, the L values varied with the rate of P fertilizer. The calcareous LV soil showed to have higher L value, though the greater relative increase were observed in distrofic LV soil, due to lower P adsorption values

  15. Short-term effects of sugarcane waste products from ethanol production plant as soil amendments on sugarcane growth and metal stabilization.

    Science.gov (United States)

    Akkajit, Pensiri; DeSutter, Thomas; Tongcumpou, Chantra

    2013-05-01

    Numerous waste products have been widely studied and used as soil amendments and metal immobilizing agents. Waste utilization from ethanol production processes as soil amendments is one of the most promising and sustainable options to help utilize materials effectively, reduce waste disposal, and add value to byproducts. As a consequence, this present work carried out a four-month pot experiment of sugarcane (Saccharum officinarum L.) cultivation in Cd and Zn contaminated soil to determine the effect of three sugarcane waste products (boiler ash, filter cake and vinasse) as soil amendment on sugarcane growth, metal translocation and accumulation in sugarcane, and fractionation of Cd and Zn in soil by the BCR sequential extraction. Four treatments were tested: (1) non-amended soil; (2) 3% w/w boiler ash; (3) 3% w/w filter cake; and (4) a combination of 1.5% boiler ash and 1.5% vinasse (w/w). Our findings showed the improved biomass production of sugarcanes; 6 and 3-fold higher for the above ground parts (from 8.5 to 57.6 g per plant) and root (from 2.1 to 6.59 g per plant), respectively, as compared to non-amended soil. Although there was no significant difference in Cd and Zn uptake in sugarcane (mg kg(-1)) between the non-amended soil and the treated soils (0.44 to 0.52 mg Cd kg(-1) and 39.9 to 48.1 mg Zn kg(-1), respectively), the reduction of the most bioavailable Cd concentration (BCR1 + 2) in the treated soils (35.4-54.5%) and the transformation of metal into an insoluble fraction (BCR3) highlighted the beneficial effects of sugarcane waste-products in promoting the sugarcane growth and Cd stabilization in soil.

  16. Residues of bioenergy production chains as soil amendments: Immediate and temporal phytotoxicity

    NARCIS (Netherlands)

    Gell, K.; Groenigen, van J.W.; Cayuela, M.L.

    2011-01-01

    The current shift towards bioenergy production increases streams of bioenergy rest-products (RPs), which are likely to end-up as soil amendments. However, their impact on soil remains unclear. In this study we evaluated crop phytotoxicity of 15 RPs from common bioenergy chains (biogas, biodiesel,

  17. Soil uses during the sugarcane fallow period: influence on soil chemical and physical properties and on sugarcane productivity

    Directory of Open Access Journals (Sweden)

    Roniram Pereira da Silva

    2014-04-01

    Full Text Available The planting of diversified crops during the sugarcane fallow period can improve the chemical and physical properties and increase the production potential of the soil for the next sugarcane cycle. The primary purpose of this study was to assess the influence of various soil uses during the sugarcane fallow period on soil chemical and physical properties and productivity after the first sugarcane harvest. The experiment was conducted in two areas located in Jaboticabal, São Paulo State, Brazil (21º 14' 05'' S, 48º 17' 09'' W with two different soil types, namely: an eutroferric Red Latosol (RLe with high-clay texture (clay content = 680 g kg-1 and an acric Red Latosol (RLa with clayey texture (clay content = 440 g kg-1. A randomized block design with five replications and four treatments (crop sequences was used. The crop sequences during the sugarcane fallow period were soybean/millet/soybean, soybean/sunn hemp/soybean, soybean/fallow/soybean, and soybean. Soil use was found not to affect chemical properties and sugarcane productivity of RLe or RLa. The soybean/millet/soybean sequence improved aggregation in the acric Latosol.

  18. Irradiated Sewage Sludge for Production of Fennel (Foeniculum vulgare L.) Plants in Sandy Soil 2- Seed production, oil content, oil constituents and heavy metals in seeds

    International Nuclear Information System (INIS)

    El-Motaium, R. A.; Abo-El-Seoud, M. A.

    2007-01-01

    Field experiment was conducted to study the impact of irradiated and non-irradiated sewage sludge applied to sandy soil on fennel plants (Foeniculum vulgare L.) productivity. In this regards, four rates of sewage sludge application were used (20, 40, 60 and 80 ton/ha) in addition to the mineral fertilizer treatment (control). Sandy soil amended with sewage sludge showed a promising effect on fennel seed yield. A linear gradual increase in seeds yield was observed as the sludge application rate increases. Seeds production increased by 41% to 308% over the control at 80 t /ha application rate, for non-irradiated and irradiated sewage sludge treatments, respectively. Irradiated sewage sludge treatments showed higher fennel seed yield than non-irradiated sewage sludge treatments.Volatile oil percent exhibited no observable variation due to the use of sewage sludge. A few and limited fluctuations could be observed. However, total oil content (cc/plot) increased due to the increase in seeds yield. The magnitude of increase in volatile oil production in response to the sewage sludge application was parallel to the increase in seeds yield. The GLC measurements of the fennel volatile oil reveal that, the t-anethole is the predominant fraction. However, fenchone was detected in relatively moderate concentration. The applied sewage sludge treatment induced some variations in fennel volatile oil constituents. The t.anethole is relatively higher in volatile oil obtained from plants grown on sandy soil fertilized with non-irradiated sewage sludge than the one fertilized with irradiated sewage sludge or chemical fertilizer. In the meantime, the obtained increase in t.anethole was accompanied by a decline in fenchone content. Seeds heavy metals (Zn, Fe, Pb, Cd) were determined. Under all sludge application rates iron and zinc concentrations were in the normal plant concentration range whereas, Cd concentrations were traces.

  19. Relative rates of nitric oxide and nitrous oxide production by nitrifiers, denitrifiers, and nitrate respirers

    Science.gov (United States)

    Anderson, I. C.; Levine, J. S.

    1986-01-01

    An account is given of the atmospheric chemical and photochemical effects of biogenic nitric and nitrous oxide emissions. The magnitude of the biogenic emission of NO is noted to remain uncertain. Possible soil sources of NO and N2O encompass nitrification by autotropic and heterotropic nitrifiers, denitrification by nitrifiers and denitrifiers, nitrate respiration by fermenters, and chemodenitrification. Oxygen availability is the primary determinant of these organisms' relative rates of activity. The characteristics of this major influence are presently investigated in light of the effect of oxygen partial pressure on NO and N2O production by a wide variety of common soil-nitrifying, denitrifying, and nitrate-respiring bacteria under laboratory conditions. The results obtained indicate that aerobic soils are primary sources only when there is sufficient moisture to furnish anaerobic microsites for denitrification.

  20. Circular linkages between soil biodiversity, fertility and plant productivity are limited to topsoil at the continental scale.

    Science.gov (United States)

    Delgado-Baquerizo, Manuel; Powell, Jeff R; Hamonts, Kelly; Reith, Frank; Mele, Pauline; Brown, Mark V; Dennis, Paul G; Ferrari, Belinda C; Fitzgerald, Anna; Young, Andrew; Singh, Brajesh K; Bissett, Andrew

    2017-08-01

    The current theoretical framework suggests that tripartite positive feedback relationships between soil biodiversity, fertility and plant productivity are universal. However, empirical evidence for these relationships at the continental scale and across different soil depths is lacking. We investigate the continental-scale relationships between the diversity of microbial and invertebrate-based soil food webs, fertility and above-ground plant productivity at 289 sites and two soil depths, that is 0-10 and 20-30 cm, across Australia. Soil biodiversity, fertility and plant productivity are strongly positively related in surface soils. Conversely, in the deeper soil layer, the relationships between soil biodiversity, fertility and plant productivity weaken considerably, probably as a result of a reduction in biodiversity and fertility with depth. Further modeling suggested that strong positive associations among soil biodiversity-fertility and fertility-plant productivity are limited to the upper soil layer (0-10 cm), after accounting for key factors, such as distance from the equator, altitude, climate and physicochemical soil properties. These findings highlight the importance of surface soil biodiversity for soil fertility, and suggest that any loss of surface soil could potentially break the links between soil biodiversity-fertility and/or fertility-plant productivity, which can negatively impact nutrient cycling and food production, upon which future generations depend. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  1. [Effects of simulated acid rain on respiration rate of cropland system with different soil pH].

    Science.gov (United States)

    Zhu, Xue-zhu; Zhang, Gao-chuan; Li, Hui

    2009-10-15

    To evaluate the effects of acid rain on the respiration rate of cropland system, an outdoor pot experiment was conducted with paddy soils of pH 5.48 (S1), pH 6.70 (S1) and pH 8.18 (S3) during the 2005-2007 wheat-growing seasons. The cropland system was exposed to acid rain by spraying the wheat foliage and irrigating the soil with simulated rainwater of T1 (pH 6.0), T2 (pH 6.0, ionic concentration was twice as rainwater T1), and T3 (pH 4.4, ionic concentration was twice as rainwater T1), respectively. The static opaque chamber-gas chromatograph method was used to measure CO2 fluxes from cropland system. The results showed that acid rain affected the respiration rate of cropland system through crop plant, and the cropland system could adapt to acid rain. Acid rainwater significantly increased the average respiration rate in alkaline soil (S3) cropland system, while it had no significant effects on the average respiration rate in neutral soil (S2) and acidic soil (S1) cropland systems. During 2005-2006, after the alkaline soil cropland system was treated with rainwater T3, the average respiration rate was 23.6% and 27.6% higher than that of alkaline soil cropland system treated with rainwater T1 and T2, respectively. During March to April, the respiration rate was enhanced with the increase of rainwater ionic concentration, while it was dropped with the decrease of rainwater pH value in acidic soil cropland system. It was demonstrated that soil pH and crop plant played important roles on the respiration rate of cropland system.

  2. Let's Break it Down: A Study of Organic Decomposition Rates in Clay Soil

    Science.gov (United States)

    Weiss, E.

    2016-12-01

    In this experiment I will be testing if temperature affects the organic decomposition rates in clay soil. I will need to be able to clean and weigh each filter paper without disrupting my data damaging or brushing off additional paper material. From there I need to be able to analyze and interpret my data to factor anything else that may affect the decomposition rates in the soil. Soil decomposers include bacteria and fungi. They obtain energy from plant and animal detritus through aerobic decomposition, which is similar to how humans break down sugar. The formula is: C6H12O6 + O2 → CO2 + H2O + energy. Besides oxygen and sugar the organisms need nutrients such as water and sustainable temperatures. Decomposition is important to us because it helps regulate soil structure, moisture, temperature, and provides nutrients to soil organisms. This matters on a global scale since decomposers release a large amount of carbon when breaking down matter, which contributes to greenhouse gasses such as carbon dioxide and methane. These greenhouse gasses affect the earth's climate. People who care about decomposition are farmers and those in agriculture, as well as environmental scientists. Even national parks might care because decomposition may affect park safety, how the park looks, and the amount of plants and wildlife. Things that can affect decomposition are the decomposers in the soil, temperature, and water or moisture. My secondary research also showed that PH and chemical composition of the soil affect the rate of decomposition.Cold or freezing temperatures can help preserve organic material in soil because it freezes the soil and moisture, making it too dense for the organic decomposers to break down the organic matter. Soil also can be preserved by drying out and being stored at 4º Celsius (or 39º Fahrenheit) for 28 days. However, soil can degrade slowly in these conditions because it is not frozen and can be oxidized.

  3. Soil quality assessment of rice production systems in South of Brazil

    NARCIS (Netherlands)

    Rodrigues de Lima, A.C.; Hoogmoed, W.B.; Brussaard, L.

    2007-01-01

    Soil quality, as a measure of the soil capacity to function, can be quantified by indicators based on physical, chemical and biological properties. Maintaining soil quality at a desirable level in the rice cropping system is a very complex issue due to the nature of the production systems used. In

  4. Earthworms (Eisenia fetida) demonstrate potential for use in soil bioremediation by increasing the degradation rates of heavy crude oil hydrocarbons.

    Science.gov (United States)

    Martinkosky, Luke; Barkley, Jaimie; Sabadell, Gabriel; Gough, Heidi; Davidson, Seana

    2017-02-15

    Crude oil contamination widely impacts soil as a result of release during oil and gas exploration and production activities. The success of bioremediation methods to meet remediation goals often depends on the composition of the crude oil, the soil, and microbial community. Earthworms may enhance bioremediation by mixing and aerating the soil, and exposing soil microorganisms to conditions in the earthworm gut that lead to increased activity. In this study, the common composting earthworm Eisenia fetida was tested for utility to improve remediation of oil-impacted soil. E. fetida survival in soil contaminated with two distinct crude oils was tested in an artificial (lab-mixed) sandy loam soil, and survival compared to that in the clean soil. Crude oil with a high fraction of light-weight hydrocarbons was more toxic to earthworms than the crude oil with a high proportion of heavy polyaromatic and aliphatic hydrocarbons. The heavier crude oil was added to soil to create a 30,000mg/kg crude oil impacted soil, and degradation in the presence of added earthworms and feed, feed alone, or no additions was monitored over time and compared. Earthworm feed was spread on top to test effectiveness of no mixing. TPH degradation rate for the earthworm treatments was ~90mg/day slowing by 200days to ~20mg/day, producing two phases of degradation. With feed alone, the rate was ~40mg/day, with signs of slowing after 500days. Both treatments reached the same end point concentrations, and exhibited faster degradation of aliphatic hydrocarbons C21, decreased. During these experiments, soils were moderately toxic during the first three months, then earthworms survived well, were active and reproduced with petroleum hydrocarbons present. This study demonstrated that earthworms accelerate bioremediation of crude oil in soils, including the degradation of the heaviest polyaromatic fractions. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. A Time Series Analysis of Global Soil Moisture Data Products for Water Cycle Studies

    Science.gov (United States)

    Zhan, X.; Yin, J.; Liu, J.; Fang, L.; Hain, C.; Ferraro, R. R.; Weng, F.

    2017-12-01

    Water is essential for sustaining life on our planet Earth and water cycle is one of the most important processes of out weather and climate system. As one of the major components of the water cycle, soil moisture impacts significantly the other water cycle components (e.g. evapotranspiration, runoff, etc) and the carbon cycle (e.g. plant/crop photosynthesis and respiration). Understanding of soil moisture status and dynamics is crucial for monitoring and predicting the weather, climate, hydrology and ecological processes. Satellite remote sensing has been used for soil moisture observation since the launch of the Scanning Multi-channel Microwave Radiometer (SMMR) on NASA's Nimbus-7 satellite in 1978. Many satellite soil moisture data products have been made available to the science communities and general public. The soil moisture operational product system (SMOPS) of NOAA NESDIS has been operationally providing global soil moisture data products from each of the currently available microwave satellite sensors and their blends. This presentation will provide an update of SMOPS products. The time series of each of these soil moisture data products are analyzed against other data products, such as precipitation and evapotranspiration from other independent data sources such as the North America Land Data Assimilation System (NLDAS). Temporal characteristics of these water cycle components are explored against some historical events, such as the 2010 Russian, 2010 China and 2012 United States droughts, 2015 South Carolina floods, etc. Finally whether a merged global soil moisture data product can be used as a climate data record is evaluated based on the above analyses.

  6. Soil Respiration under Different Land Uses in Eastern China

    Science.gov (United States)

    Fan, Li-Chao; Yang, Ming-Zhen; Han, Wen-Yan

    2015-01-01

    Land-use change has a crucial influence on soil respiration, which further affects soil nutrient availability and carbon stock. We monitored soil respiration rates under different land-use types (tea gardens with three production levels, adjacent woodland, and a vegetable field) in Eastern China at weekly intervals over a year using the dynamic closed chamber method. The relationship between soil respiration and environmental factors was also evaluated. The soil respiration rate exhibited a remarkable single peak that was highest in July/August and lowest in January. The annual cumulative respiration flux increased by 25.6% and 20.9% in the tea garden with high production (HP) and the vegetable field (VF), respectively, relative to woodland (WL). However, no significant differences were observed between tea gardens with medium production (MP), low production (LP), WL, and VF. Soil respiration rates were significantly and positively correlated with organic carbon, total nitrogen, and available phosphorous content. Each site displayed a significant exponential relationship between soil respiration and soil temperature measured at 5 cm depth, which explained 84–98% of the variation in soil respiration. The model with a combination of soil temperature and moisture was better at predicting the temporal variation of soil respiration rate than the single temperature model for all sites. Q10 was 2.40, 2.00, and 1.86–1.98 for VF, WL, and tea gardens, respectively, indicating that converting WL to VF increased and converting to tea gardens decreased the sensitivity of soil respiration to temperature. The equation of the multiple linear regression showed that identical factors, including soil organic carbon (SOC), soil water content (SWC), pH, and water soluble aluminum (WSAl), drove the changes in soil respiration and Q10 after conversion of land use. Temporal variations of soil respiration were mainly controlled by soil temperature, whereas spatial variations were

  7. Understorey productivity in temperate grassy woodland responds to soil water availability but not to elevated [CO2 ].

    Science.gov (United States)

    Collins, Luke; Bradstock, Ross A; Resco de Dios, Victor; Duursma, Remko A; Velasco, Sabrina; Boer, Matthias M

    2018-06-01

    Rising atmospheric [CO 2 ] and associated climate change are expected to modify primary productivity across a range of ecosystems globally. Increasing aridity is predicted to reduce grassland productivity, although rising [CO 2 ] and associated increases in plant water use efficiency may partially offset the effect of drying on growth. Difficulties arise in predicting the direction and magnitude of future changes in ecosystem productivity, due to limited field experimentation investigating climate and CO 2 interactions. We use repeat near-surface digital photography to quantify the effects of water availability and experimentally manipulated elevated [CO 2 ] (eCO 2 ) on understorey live foliage cover and biomass over three growing seasons in a temperate grassy woodland in south-eastern Australia. We hypothesised that (i) understorey herbaceous productivity is dependent upon soil water availability, and (ii) that eCO 2 will increase productivity, with greatest stimulation occurring under conditions of low water availability. Soil volumetric water content (VWC) determined foliage cover and growth rates over the length of the growing season (August to March), with low VWC (productivity. However, eCO 2 did not increase herbaceous cover and biomass over the duration of the experiment, or mitigate the effects of low water availability on understorey growth rates and cover. Our findings suggest that projected increases in aridity in temperate woodlands are likely to lead to reduced understorey productivity, with little scope for eCO 2 to offset these changes. © 2018 John Wiley & Sons Ltd.

  8. Preliminary Evaluation of the SMAP Radiometer Soil Moisture Product over China Using In Situ Data

    Directory of Open Access Journals (Sweden)

    Yayong Sun

    2017-03-01

    Full Text Available The Soil Moisture Active Passive (SMAP satellite makes coincident global measurements of soil moisture using an L-band radar instrument and an L-band radiometer. It is crucial to evaluate the errors in the newest L-band SMAP satellite-derived soil moisture products, before they are routinely used in scientific research and applications. This study represents the first evaluation of the SMAP radiometer soil moisture product over China. In this paper, a preliminary evaluation was performed using sparse in situ measurements from 655 China Meteorological Administration (CMA monitoring stations between 1 April 2015 and 31 August 2016. The SMAP radiometer-derived soil moisture product was evaluated against two schemes of original soil moisture and the soil moisture anomaly in different geographical zones and land cover types. Four performance metrics, i.e., bias, root mean square error (RMSE, unbiased root mean square error (ubRMSE, and the correlation coefficient (R, were used in the accuracy evaluation. The results indicated that the SMAP radiometer-derived soil moisture product agreed relatively well with the in situ measurements, with ubRMSE values of 0.058 cm3·cm−3 and 0.039 cm3·cm−3 based on original data and anomaly data, respectively. The values of the SMAP radiometer-based soil moisture product were overestimated in wet areas, especially in the Southwest China, South China, Southeast China, East China, and Central China zones. The accuracies over croplands and in Northeast China were the worst. Soil moisture, surface roughness, and vegetation are crucial factors contributing to the error in the soil moisture product. Moreover, radio frequency interference contributes to the overestimation over the northern portion of the East China zone. This study provides guidelines for the application of the SMAP-derived soil moisture product in China and acts as a reference for improving the retrieval algorithm.

  9. Tectonic uplift and denudation rate influence soil chemical weathering intensity in a semi-arid environment, southeast Spain: physico-chemical and mineralogical evidence

    Science.gov (United States)

    Ameijeiras-Mariño, Yolanda; Opfergelt, Sophie; Schoonejans, Jérôme; Vanacker, Veerle; Sonnet, Philippe; Delmelle, Pierre

    2015-04-01

    Tectonic uplift is known to influence denudation rates. Denudation, including chemical weathering and physical erosion, affects soil production rates and weathering intensities. At topographic steady state, weathering can be transport- or weathering-limited. In the transport-limited regime, low denudation rates should lead to comparatively high weathering intensities, while in the weathering-limited case high denudation rates are associated with lower weathering intensities. Here, we test if this relationship applies to semi-arid environments where chemical weathering is generally slow. Three catchments (EST, FIL and CAB) were studied in the Internal Zone of the Betic Cordillera in southeast Spain, spanning a range of increasing uplift rates (10-170 mm/kyr) and increasing denudation rates (20-250 mm/kyr) from EST to CAB. In each catchment, two ridgetop soil profiles were sampled down to the bedrock. The three catchments have similar vegetation and climatic conditions, with precipitation of 250- 315 mm/yr and mean annual temperature of 15-17 °C. The mineralogy of the bedrock, as determined by XRD, is similar across the three catchments and is characterized by the presence of quartz, muscovite, clinochlore, biotite and plagioclase. This primary mineral assemblage is also found in the catchment soils, indicating that the soils studied derive from the same parent material. The soil clay-size fraction is dominated by kaolinite, vermiculite and illite. However, the proportions of the soil primary and secondary minerals vary between the catchment sites. The abundance of biotite decreases from CAB (14%) to EST (4%), whereas the quartz and clay contents show an opposite tendency (from 30 to 69% and 9.9 to 14.3%, respectively). Further, the abundance of vermiculite increases from CAB to EST. The results are interpreted in terms of increasing weathering intensity from CAB to EST by weathering of biotite into vermiculite and enrichment of soils on more weathering resistant

  10. Nitrous oxide production in soil isolates of nitrate-ammonifying bacteria

    NARCIS (Netherlands)

    Streminska, M.A.; Felgate, H.; Rowley, G.; Richardson, D.J.; Baggs, E.M.

    2012-01-01

    Here we provide the first demonstration of the potential for N2O production by soil-isolated nitrate-ammonifying bacteria under different C and N availabilities, building on characterizations informed from model strains. The potential for soil-isolated Bacillus sp. and Citrobacter sp. to reduce

  11. Nitrous oxide production and consumption potential in an agricultural and a forest soil

    DEFF Research Database (Denmark)

    Yu, Kewei; Struwe, Sten; Kjøller, Annelise

    2008-01-01

    Both a laboratory incubation experiment using soils from an agricultural field and a forest and field measurements at the same locations were conducted to determine nitrous oxide (N2O) production and consumption (reduction) potentials using the acetylene (C2H2) inhibition technique. Results from...... measurements show that average N2O emission rates were 0.56 and 0.59 kg N ha-1 in the agricultural field and forest, respectively. When C2H2 was provided in the field measurements, N2O emission rates from the agricultural field and forest increased by 38 and 51%, respectively. Nitrous oxide consumption under...

  12. Effect of fertilizer formulation and bioaugmentation on biodegradation and leaching of crude oils and refined products in soils.

    Science.gov (United States)

    Coulon, F; Brassington, K J; Bazin, R; Linnet, P E; Thomas, K A; Mitchell, T R; Lethbridge, G; Smith, J W N; Pollarda, S J T

    2012-09-01

    The effects of soil characteristics and oil types as well as the efficacy of two fertilizer formulations and three bioaugmentation packages in improving the bioremediation of oil-contaminated soils were assessed as a means of ex situ treatment selection and optimization through seven laboratory microcosm studies. The influence of bioremediation on leaching of oil from the soil was also investigated. The studies demonstrated the benefits ofbiostimulation to overcome nutrient limitation, as most of the soils were nutrient depleted. The application of both liquid and pelleted slow-release N and P fertilizers increased both the hydrocarbon biodegradation rates (by a factor of 1.4 to 2.9) and the percentage of hydrocarbon mass degraded (by > 30% after 12 weeks and 80% after 37 weeks), when compared with the unamended soils. Slow-release fertilizers can be particularly useful when multiple liquid applications are not practical or cost-effective. Bioaugmentation products containing inoculum plus fertilizer also increased biodegradation by 20% to 37% compared with unamended biotic controls; however, there was no clear evidence of additional benefits due to the inocula, compared with fertilizer alone. Therefore biostimulation is seen as the most cost-effective bioremediation strategy for contaminated soils with the levels of crude oil and refined products used in this study. However, site-specific considerations remain essential for establishing the treatability of oil-contaminated soils.

  13. Seasonal soil VOC exchange rates in a Mediterranean holm oak forest and their responses to drought conditions

    Science.gov (United States)

    Asensio, Dolores; Peñuelas, Josep; Ogaya, Romà; Llusià, Joan

    Available information on soil volatile organic compound (VOC) exchange, emissions and uptake, is very scarce. We here describe the amounts and seasonality of soil VOC exchange during a year in a natural Mediterranean holm oak forest growing in Southern Catalonia. We investigated changes in soil VOC dynamics in drought conditions by decreasing the soil moisture to 30% of ambient conditions by artificially excluding rainfall and water runoff, and predicted the response of VOC exchange to the drought forecasted in the Mediterranean region for the next decades by GCM and ecophysiological models. The annual average of the total (detected) soil VOC and total monoterpene exchange rates were 3.2±3.2 and -0.4±0.3 μg m -2 h -1, respectively, in control plots. These values represent 0.003% of the total C emitted by soil at the study site as CO 2 whereas the annual mean of soil monoterpene exchange represents 0.0004% of total C. Total soil VOC exchange rates in control plots showed seasonal variations following changes in soil moisture and phenology. Maximum values were found in spring (17±8 μg m -2 h -1). Although there was no significant global effect of drought treatment on the total soil VOC exchange rates, annual average of total VOC exchange rates in drought plots resulted in an uptake rate (-0.5±1.8 μg m -2 h -1) instead of positive net emission rates. Larger soil VOC and monoterpene exchanges were measured in drought plots than in control plots in summer, which might be mostly attributable to autotrophic (roots) metabolism. The results show that the diversity and magnitude of monoterpene and VOC soil emissions are low compared with plant emissions, that they are driven by soil moisture, that they represent a very small part of the soil-released carbon and that they may be strongly reduced or even reversed into net uptakes by the predicted decreases of soil water availability in the next decades. In all cases, it seems that VOC fluxes in soil might have greater

  14. Effect of rain drop washes on soil fertility in cotton production zone of ...

    African Journals Online (AJOL)

    Crop production in the Sahel is limited by nutrients availability. The study aimed to estimate the contribution of avifauna, crop rotation and trees to soil fertility and crop production improvement. Pot experiment was carried out with soils sampled in Faidherbia albida parklands in cotton production zone of West Burkina Faso.

  15. Soil physical property changes at the North American long-term soil productivity study sites: 1 and 5 years after compaction

    Science.gov (United States)

    Deborah S. Page-Dumroese; Martin F. Jurgensen; Allan E. Tiarks; Felix Ponder; Felipe G. Sanchez; Robert L. Fleming; J. Marty Kranabetter; Robert F. Powers; Douglas M. Stone; John D. Elioff; D. Andrew. Scott

    2006-01-01

    The impact of forest management operations on soil physical properties is important to understand, since management can significantly change site productivity by altering root growth potential, water infiltration and soil erosion, and water and nutrient availability. We studied soil bulk density and strength changes as indicators of soil compaction before harvesting...

  16. Methyl Mercury Production In Tropical Hydromorphic Soils: Impact Of Gold Mining.

    Science.gov (United States)

    Guedron, S.; Charlet, L.; Harris, J.; Grimaldi, M.; Cossa, D.

    2007-12-01

    Artisanal alluvial gold mining is important in many tropical developing countries and several million people are involved worldwide. The dominant use of mercury for gold amalgamation in this activity leads to mercury accumulation in soils, to sediment contamination and to methyl mercury (MMHg) bioaccumulation along the food chain. In this presentation we will present recent data on methyl mercury production in hydromorphic soils and tailing ponds from a former gold mining area located in French Guiana (South America). Comparison of specific fluxes between a pristine sub watershed and the contaminated watershed shows that former mining activities lead to a large enhancement of dissolved and particulate MMHg emissions at least by a factor of 4 and 6, respectively. MMHg production was identified in sediments from tailing ponds and in surrounding hydromorphic soils. Moreover, interstitial soil water and tailing pond water profiles sampled in an experimental tailing pond demonstrate the presence of a large MMHg production in the suboxic areas. Both tailing ponds and hydromorphic soils present geochemical conditions that are favorable to bacterial mercury methylation (high soil Hg content, high aqueous ferric iron and dissolved organic carbon concentrations). Although sulfate-reducing bacteria have been described as being the principal mercury methylating bacteria, the positive correlation between dissolved MMHg and ferrous iron concentrations argue for a significant role of iron-reducing bacteria. Identifications by sequencing fragments of 16S rRNA from total soil DNA support these interpretations. This study demonstrates that current and past artisanal gold mining in the tropics lead to methyl mercury production in contaminated areas. As artisanal activities are increasing with increasing gold prices, the bio- magnification of methyl mercury in fish presents an increasing threat to local populations whose diet relies on fish consumption.

  17. Soil and phosphorus accretion rates in sub-tropical wetlands: Everglades Stormwater Treatment Areas as a case example.

    Science.gov (United States)

    Bhomia, R K; Inglett, P W; Reddy, K R

    2015-11-15

    Wetlands are known to serve as sinks for particulate matter and associated nutrients and contaminants. Consequently rate of soil accretion is critical for continued performance of wetlands to provide ecosystem services including water quality improvement and reduce excess contaminant loads into downstream waters. Here we demonstrate a new technique to determine rate of soil accretion in selected subtropical treatment wetlands located in southern USA. We also report changes in soil accretion rates and subsequent phosphorus (P) removal efficiency with increasing operational history of these treatment wetlands. Utilizing discernible signatures preserved within the soil depth profiles, 'change points' (CP) that corresponded to specific events in the life history of a wetland were determined. The CP was observed as an abrupt transition in the physico-chemical properties of soil as a manifestation of prevailing historical conditions (e.g. startup of treatment wetlands in this case). Vertical depth of CP from the soil surface was equivalent to the depth of recently accreted soil (RAS) and used for soil accretion rate calculations. Annual soil and P accretion rates determined using CP technique (CPT) in studied wetlands ranged from 1.0±0.3 to 1.7±0.8 cm yr(-1) and 1.3±0.6 to 3.3±2 g m(-2) yr(-1), respectively. There was no difference in RAS depth between emergent and submerged aquatic vegetation communities found at the study location. Our results showed that soil and P accretion rates leveled off after 10 yr of treatment wetlands' operation. On comparison, soil accretion rates and RAS depth determined by CPT were commensurate with that measured by other techniques. CPT can be easily used where a reliable record of wetland establishment date or some significant alteration/perturbation is available. This technique offers a relatively simple alternative to determine vertical accretion rates in free-water surface wetlands. Copyright © 2015 Elsevier B.V. All rights

  18. Evaluation of Spatial-Temporal Variation of Soil Detachment Rate Potential in Rill Erosion, Case study: Doshmanziari Rainfed Lands, Fars province

    Directory of Open Access Journals (Sweden)

    H. Karimi

    2017-01-01

    Full Text Available Introduction: Soil erosion by water is one of the most widespread forms of land degradation and it has caused many undesirable consequences in last decades. On steep slopes, rill erosion is the most important type of erosion, which produces sediment and rill flow. It can be also considered as a vehicle for transporting soil particles detached from upland areas. Recent studies indicate that soil detachment rates are significantly influenced by land use. It is also known that there is a major difference between detachment rates of disturbed and natural soils (Zhang et al., 2003. Plowing rills especially in steep slopes increases sediment production. Sun et al. (2013 reported that the contribution of rill erosion in hill slope lands in china was more than 70%, which was approximately 50% of total soil erosion. In addition, measured soil loss is statistically related to hydraulic indicators such as slope, water depth, flow velocity, flow shear stress and stream power (Knapen et al., 2007. This study aims to evaluate the effects of hydraulic variables (shear stress and stream power on spatial-temporal soil detachment rate. The focus is on the plowing rills in hillslope areas under wheat dry farming cultivation. Materials and Methods: The study area is located in hilly slopes with the slope of 22.56% under dry farming wheat cultivation at 60 km of west of Shiraz, Iran. Top-down conventional plowing was carried out in order to create 10 meters furrows. Slope and cross sections of rills were measured throughout the experiment at 1 m intervals by rill-meter. Water was added to the top of the rills for 10 minutes and inflow rates were 10, 15 and 20 L min-1. Hydraulic parameters such as shear stress and stream power were calculated measuring rill morphology and water depth. Flow velocity and hydraulic radius along the different rill experiments were also calculated. Sediment concentrations were measured in three equal regular time and distance intervals

  19. Responses of plant available water and forest productivity to variably layered coarse textured soils

    Science.gov (United States)

    Huang, Mingbin; Barbour, Lee; Elshorbagy, Amin; Si, Bing; Zettl, Julie

    2010-05-01

    Reforestation is a primary end use for reconstructed soils following oil sands mining in northern Alberta, Canada. Limited soil water conditions strongly restrict plant growth. Previous research has shown that layering of sandy soils can produce enhanced water availability for plant growth; however, the effect of gradation on these enhancements is not well defined. The objective of this study was to evaluate the effect of soil texture (gradation and layering) on plant available water and consequently on forest productivity for reclaimed coarse textured soils. A previously validated system dynamics (SD) model of soil moisture dynamics was coupled with ecophysiological and biogeochemical processes model, Biome-BGC-SD, to simulate forest dynamics for different soil profiles. These profiles included contrasting 50 cm textural layers of finer sand overlying coarser sand in which the sand layers had either a well graded or uniform soil texture. These profiles were compared to uniform profiles of the same sands. Three tree species of jack pine (Pinus banksiana Lamb.), white spruce (Picea glauce Voss.), and trembling aspen (Populus tremuloides Michx.) were simulated using a 50 year climatic data base from northern Alberta. Available water holding capacity (AWHC) was used to identify soil moisture regime, and leaf area index (LAI) and net primary production (NPP) were used as indices of forest productivity. Published physiological parameters were used in the Biome-BGC-SD model. Relative productivity was assessed by comparing model predictions to the measured above-ground biomass dynamics for the three tree species, and was then used to study the responses of forest leaf area index and potential productivity to AWHC on different soil profiles. Simulated results indicated soil layering could significantly increase AWHC in the 1-m profile for coarse textured soils. This enhanced AWHC could result in an increase in forest LAI and NPP. The increased extent varied with soil

  20. Phosphate fertilisers and management for sustainable crop production in tropical acid soils

    International Nuclear Information System (INIS)

    Chien, S.H.; Friesen, D.K.

    2000-01-01

    Extensive research has been conducted over the past 25 years on the management of plant nutrients, especially N and P, for crop production on acidic infertile tropical soils. Under certain conditions, the use of indigenous phosphate rock (PR) and modified PR products, such as partially acidulated PR or compacted mixtures of PR with superphosphates, are attractive alternatives, both agronomically and economically, to the use of conventional water-soluble P fertilisers for increasing crop productivity on Oxisols and Ultisols. A combination of the effects of proper P and N management including biological N 2 fixation, judicious use of lime, and the use of acid-soil tolerant and/or P-efficient cultivars in cropping systems that enhance nutrient cycling and use efficiency, can provide an effective technology to sustainably increase crop productivity and production in tropical agro-ecosystems dominated by these acid soils. (author)

  1. Soil-restoration rate and initial soil formation trends on example of anthropogenically affected soils of opencast mine in Kursk region, Russian Federation

    Science.gov (United States)

    Pigareva, Tatiana

    2015-04-01

    The mining industry is one of the main factors which anthropogenically change the environment. Mining process results in removing of the rocks and mechanical changes of considerable amounts of ground. One of the main results of mining arising of antropic ecosystems as well as increasing of the new created soils total area is technosols. The main factor controlling the soil formation in postmining environment is the quality of spoiled materials. Initial soil formation has been investigated on spoils of the largest iron ore extraction complex in Russia - Mikhailovsky mining and concentration complex which is situated in Kursk region, Russia. Investigated soils are presented by monogenetic weak developed soils of different age (10-15-20 years). Young soils are formed on the loess parent materials (20 year-old soil), or on a mix of sand and clay overburdens (15 and 10-year-old soils). Anthropogenically affected soils are characterized by well-developed humus horizon which is gradually replaced by weakly changed soil-building rocks (profile type A-C for 10-, 15-years old soils, and A-AC-C for 20 years old soils). Gray-humus soils are characterized by presence of diagnostic humus horizon gradually replaced by soil-building rock. The maximum intensity of humus accumulation has been determined in a semi-hydromorphic 10-year-old soil developed on the mixed heaps which is connected with features of water-air conditions complicating mineralization of plant remnants. 20-year-old soil on loess is characterized by rather high rate of organic substances accumulation between all the automorphous soils. It was shown that one of the most effective restoration ways for anthropogenically affected soils is a biological reclamation. Since overburdens once appeared on a day surface are overgrown badly in the first years, they are subject to influence of water and wind erosion. Our researchers have found out that permanent grasses are able to grow quickly; they accumulate a considerable

  2. Productivity of aboveground coarse wood biomass and stand age related to soil hydrology of Amazonian forests in the Purus-Madeira interfluvial area

    Science.gov (United States)

    Cintra, B. B. L.; Schietti, J.; Emillio, T.; Martins, D.; Moulatlet, G.; Souza, P.; Levis, C.; Quesada, C. A.; Schöngart, J.

    2013-04-01

    The ongoing demand for information on forest productivity has increased the number of permanent monitoring plots across the Amazon. Those plots, however, do not comprise the whole diversity of forest types in the Amazon. The complex effects of soil, climate and hydrology on the productivity of seasonally waterlogged interfluvial wetland forests are still poorly understood. The presented study is the first field-based estimate for tree ages and wood biomass productivity in the vast interfluvial region between the Purus and Madeira rivers. We estimate stand age and wood biomass productivity by a combination of tree-ring data and allometric equations for biomass stocks of eight plots distributed along 600 km in the Purus-Madeira interfluvial area that is crossed by the BR-319 highway. We relate stand age and wood biomass productivity to hydrological and edaphic conditions. Mean productivity and stand age were 5.6 ± 1.1 Mg ha-1 yr-1 and 102 ± 18 yr, respectively. There is a strong relationship between tree age and diameter, as well as between mean diameter increment and mean wood density within a plot. Regarding the soil hydromorphic properties we find a positive correlation with wood biomass productivity and a negative relationship with stand age. Productivity also shows a positive correlation with the superficial phosphorus concentration. In addition, superficial phosphorus concentration increases with enhanced soil hydromorphic condition. We raise three hypotheses to explain these results: (1) the reduction of iron molecules on the saturated soils with plinthite layers close to the surface releases available phosphorous for the plants; (2) the poor structure of the saturated soils creates an environmental filter selecting tree species of faster growth rates and shorter life spans and (3) plant growth on saturated soil is favored during the dry season, since there should be low restrictions for soil water availability.

  3. Production, soil erosion and economic failure in new citrus plantations in Eastern Spain

    Science.gov (United States)

    Giménez Morera, Antonio; Carles membrado, Joan; Cerdà, Artemi; Ángel González Peñaloza, Félix

    2013-04-01

    their neighboring mountain slopes. The interest of orange groves is not only economic, but also environmental. Although the traditional farming developed a beautiful man made landscape of terraces and irrigation ditches, the development of new irrigation systems by means of drips contributed to new plantations that removed the ditches and the terraces. Those changes are triggering intense soil erosion rates such were shown by previous researchers in Valencia (Cerdà et al., 2009). This impact is also shown in other regions with a similar citrus production evolution, and China is a clear example (Wang et al., 2010; Liu et al., 2012). This research evaluates the production and the cost of production, the economic investment in the establishment of the new citrus plantations and the revenues of 5 farms in the Canyoles river watershed in Eastern Spain. The soil erosion rates measured by means of rainfall simulation experiments in each farm by means of thunderstorms of 10 years return period (55 mm h-1) and by five-year survey by means of topographical measurements. The results show that the soil losses in the new plantation are extremely high, that the investments in the new plantation reached 18352 € ha-1 and that the revenues do not cover the expenses of production. Soil erosion measured since 2007 to 2011 show values that range from 7.54 to 56.76 Mg ha-1 year-1 and show a mean value of 28.45 Mg ha-1 year-1. Rainfall simulation experiments shown that the soil losses were very high as other researched found in new citrus plantations. The comparison with other land uses and agriculture crop and managements shown that soil erosion is higher in then new chemically treated plantations (Cerdà, 2002), and even higher that on road embankments (Cerdà, 2007) and rainfed agriculture soil (García Orenes et al., 2009), although the water repellency found was very low in comparison to organic farming orange plantations (González et al., 2012). The current situation of a high

  4. No apparent costs for facultative antibiotic production by the soil bacterium Pseudomonas fluorescens Pf0-1.

    Directory of Open Access Journals (Sweden)

    Paolina Garbeva

    Full Text Available BACKGROUND: Many soil-inhabiting bacteria are known to produce secondary metabolites that can suppress microorganisms competing for the same resources. The production of antimicrobial compounds is expected to incur fitness costs for the producing bacteria. Such costs form the basis for models on the co-existence of antibiotic-producing and non-antibiotic producing strains. However, so far studies quantifying the costs of antibiotic production by bacteria are scarce. The current study reports on possible costs, for antibiotic production by Pseudomonas fluorescens Pf0-1, a soil bacterium that is induced to produce a broad-spectrum antibiotic when it is confronted with non-related bacterial competitors or supernatants of their cultures. METHODOLOGY AND PRINCIPAL FINDINGS: We measured the possible cost of antibiotic production for Pseudomonas fluorescens Pf0-1 by monitoring changes in growth rate with and without induction of antibiotic production by supernatant of a bacterial competitor, namely Pedobacter sp.. Experiments were performed in liquid as well as on semi-solid media under nutrient-limited conditions that are expected to most clearly reveal fitness costs. Our results did not reveal any significant costs for production of antibiotics by Pseudomonas fluorescens Pf0-1. Comparison of growth rates of the antibiotic-producing wild-type cells with those of non-antibiotic producing mutants did not reveal costs of antibiotic production either. SIGNIFICANCE: Based on our findings we propose that the facultative production of antibiotics might not be selected to mitigate metabolic costs, but instead might be advantageous because it limits the risk of competitors evolving resistance, or even the risk of competitors feeding on the compounds produced.

  5. Soil erosion and sediment production on watershed landscapes: Processes and control

    Science.gov (United States)

    Peter F. Ffolliott; Kenneth N. Brooks; Daniel G. Neary; Roberto Pizarro Tapia; Pablo Garcia-Chevesich

    2013-01-01

    Losses of the soil resources from otherwise productive and well functioning watersheds is often a recurring problem confronting hydrologists and watershed managers. These losses of soil have both on-site and off-site effects on the watershed impacted. In addition to the loss of inherent soil resources through erosion processes, on-site effects can include the breakdown...

  6. Modeling temporal and large-scale spatial variability of soil respiration from soil water availability, temperature and vegetation productivity indices

    Science.gov (United States)

    Reichstein, Markus; Rey, Ana; Freibauer, Annette; Tenhunen, John; Valentini, Riccardo; Banza, Joao; Casals, Pere; Cheng, Yufu; Grünzweig, Jose M.; Irvine, James; Joffre, Richard; Law, Beverly E.; Loustau, Denis; Miglietta, Franco; Oechel, Walter; Ourcival, Jean-Marc; Pereira, Joao S.; Peressotti, Alessandro; Ponti, Francesca; Qi, Ye; Rambal, Serge; Rayment, Mark; Romanya, Joan; Rossi, Federica; Tedeschi, Vanessa; Tirone, Giampiero; Xu, Ming; Yakir, Dan

    2003-12-01

    Field-chamber measurements of soil respiration from 17 different forest and shrubland sites in Europe and North America were summarized and analyzed with the goal to develop a model describing seasonal, interannual and spatial variability of soil respiration as affected by water availability, temperature, and site properties. The analysis was performed at a daily and at a monthly time step. With the daily time step, the relative soil water content in the upper soil layer expressed as a fraction of field capacity was a good predictor of soil respiration at all sites. Among the site variables tested, those related to site productivity (e.g., leaf area index) correlated significantly with soil respiration, while carbon pool variables like standing biomass or the litter and soil carbon stocks did not show a clear relationship with soil respiration. Furthermore, it was evidenced that the effect of precipitation on soil respiration stretched beyond its direct effect via soil moisture. A general statistical nonlinear regression model was developed to describe soil respiration as dependent on soil temperature, soil water content, and site-specific maximum leaf area index. The model explained nearly two thirds of the temporal and intersite variability of soil respiration with a mean absolute error of 0.82 μmol m-2 s-1. The parameterized model exhibits the following principal properties: (1) At a relative amount of upper-layer soil water of 16% of field capacity, half-maximal soil respiration rates are reached. (2) The apparent temperature sensitivity of soil respiration measured as Q10 varies between 1 and 5 depending on soil temperature and water content. (3) Soil respiration under reference moisture and temperature conditions is linearly related to maximum site leaf area index. At a monthly timescale, we employed the approach by [2002] that used monthly precipitation and air temperature to globally predict soil respiration (T&P model). While this model was able to

  7. Modelling temporal and large-scale spatial variability of soil respiration from soil water availability, temperature and vegetation productivity indices

    Science.gov (United States)

    Reichstein, M.; Rey, A.; Freibauer, A.; Tenhunen, J.; Valentini, R.; Soil Respiration Synthesis Team

    2003-04-01

    Field-chamber measurements of soil respiration from 17 different forest and shrubland sites in Europe and North America were summarized and analyzed with the goal to develop a model describing seasonal, inter-annual and spatial variability of soil respiration as affected by water availability, temperature and site properties. The analysis was performed at a daily and at a monthly time step. With the daily time step, the relative soil water content in the upper soil layer expressed as a fraction of field capacity was a good predictor of soil respiration at all sites. Among the site variables tested, those related to site productivity (e.g. leaf area index) correlated significantly with soil respiration, while carbon pool variables like standing biomass or the litter and soil carbon stocks did not show a clear relationship with soil respiration. Furthermore, it was evidenced that the effect of precipitation on soil respiration stretched beyond its direct effect via soil moisture. A general statistical non-linear regression model was developed to describe soil respiration as dependent on soil temperature, soil water content and site-specific maximum leaf area index. The model explained nearly two thirds of the temporal and inter-site variability of soil respiration with a mean absolute error of 0.82 µmol m-2 s-1. The parameterised model exhibits the following principal properties: 1) At a relative amount of upper-layer soil water of 16% of field capacity half-maximal soil respiration rates are reached. 2) The apparent temperature sensitivity of soil respiration measured as Q10 varies between 1 and 5 depending on soil temperature and water content. 3) Soil respiration under reference moisture and temperature conditions is linearly related to maximum site leaf area index. At a monthly time-scale we employed the approach by Raich et al. (2002, Global Change Biol. 8, 800-812) that used monthly precipitation and air temperature to globally predict soil respiration (T

  8. Impact of Soil Heavy Metal Pollution on Food Safety in China.

    Science.gov (United States)

    Zhang, Xiuying; Zhong, Taiyang; Liu, Lei; Ouyang, Xiaoying

    2015-01-01

    Food safety is a major concern for the Chinese public. This study collected 465 published papers on heavy metal pollution rates (the ratio of the samples exceeding the Grade II limits for Chinese soils, the Soil Environmental Quality Standard-1995) in farmland soil throughout China. The results showed that Cd had the highest pollution rate of 7.75%, followed by Hg, Cu, Ni and Zn, Pb and Cr had the lowest pollution rates at lower than 1%. The total pollution rate in Chinese farmland soil was 10.18%, mainly from Cd, Hg, Cu, and Ni. The human activities of mining and smelting, industry, irrigation by sewage, urban development, and fertilizer application released certain amounts of heavy metals into soil, which resulted in the farmland soil being polluted. Considering the spatial variations of grain production, about 13.86% of grain production was affected due to the heavy metal pollution in farmland soil. These results many provide valuable information for agricultural soil management and protection in China.

  9. Impact of Soil Heavy Metal Pollution on Food Safety in China

    Science.gov (United States)

    Zhang, Xiuying; Zhong, Taiyang; Liu, Lei; Ouyang, Xiaoying

    2015-01-01

    Food safety is a major concern for the Chinese public. This study collected 465 published papers on heavy metal pollution rates (the ratio of the samples exceeding the Grade II limits for Chinese soils, the Soil Environmental Quality Standard-1995) in farmland soil throughout China. The results showed that Cd had the highest pollution rate of 7.75%, followed by Hg, Cu, Ni and Zn, Pb and Cr had the lowest pollution rates at lower than 1%. The total pollution rate in Chinese farmland soil was 10.18%, mainly from Cd, Hg, Cu, and Ni. The human activities of mining and smelting, industry, irrigation by sewage, urban development, and fertilizer application released certain amounts of heavy metals into soil, which resulted in the farmland soil being polluted. Considering the spatial variations of grain production, about 13.86% of grain production was affected due to the heavy metal pollution in farmland soil. These results many provide valuable information for agricultural soil management and protection in China. PMID:26252956

  10. Soil Aggregate Stability and Grassland Productivity Associations in a Northern Mixed-Grass Prairie.

    Directory of Open Access Journals (Sweden)

    Kurt O Reinhart

    Full Text Available Soil aggregate stability data are often predicted to be positively associated with measures of plant productivity, rangeland health, and ecosystem functioning. Here we revisit the hypothesis that soil aggregate stability is positively associated with plant productivity. We measured local (plot-to-plot variation in grassland community composition, plant (aboveground biomass, root biomass, % water-stable soil aggregates, and topography. After accounting for spatial autocorrelation, we observed a negative association between % water-stable soil aggregates (0.25-1 and 1-2 mm size classes of macroaggregates and dominant graminoid biomass, and negative associations between the % water-stable aggregates and the root biomass of a dominant sedge (Carex filifolia. However, variation in total root biomass (0-10 or 0-30 cm depths was either negatively or not appreciably associated with soil aggregate stabilities. Overall, regression slope coefficients were consistently negative thereby indicating the general absence of a positive association between measures of plant productivity and soil aggregate stability for the study area. The predicted positive association between factors was likely confounded by variation in plant species composition. Specifically, sampling spanned a local gradient in plant community composition which was likely driven by niche partitioning along a subtle gradient in elevation. Our results suggest an apparent trade-off between some measures of plant biomass production and soil aggregate stability, both known to affect the land's capacity to resist erosion. These findings further highlight the uncertainty of plant biomass-soil stability associations.

  11. Predicting soil formation on the basis of transport-limited chemical weathering

    Science.gov (United States)

    Yu, Fang; Hunt, Allen Gerhard

    2018-01-01

    Soil production is closely related to chemical weathering. It has been shown that, under the assumption that chemical weathering is limited by solute transport, the process of soil production is predictable. However, solute transport in soil cannot be described by Gaussian transport. In this paper, we propose an approach based on percolation theory describing non-Gaussian transport of solute to predict soil formation (the net production of soil) by considering both soil production from chemical weathering and removal of soil from erosion. Our prediction shows agreement with observed soil depths in the field. Theoretical soil formation rates are also compared with published rates predicted using soil age-profile thickness (SAST) method. Our formulation can be incorporated directly into landscape evolution models on a point-to-point basis as long as such models account for surface water routing associated with overland flow. Further, our treatment can be scaled-up to address complications associated with continental-scale applications, including those from climate change, such as changes in vegetation, or surface flow organization. The ability to predict soil formation rates has implications for understanding Earth's climate system on account of the relationship to chemical weathering of silicate minerals with the associated drawdown of atmospheric carbon, but it is also important in geomorphology for understanding landscape evolution, including for example, the shapes of hillslopes, and the net transport of sediments to sedimentary basins.

  12. Runoff and Sediment Production under the Similar Rainfall Events in Different Aggregate Sizes of an Agricultural Soil

    Directory of Open Access Journals (Sweden)

    S. F. Eslami

    2016-09-01

    Full Text Available Introduction: Soil erosion by water is the most serious form of land degradation throughout the world, particularly in arid and semi-arid regions. In these areas, soils are weakly structured and are easily disrupted by raindrop impacts. Soil erosion is strongly affected by different factors such as rainfall characteristics, slope properties, vegetation cover, conservation practices, and soil erodibility. Different physicochemical soil properties such texture, structure, infiltration rate, organic matter, lime and exchangeable sodium percentage can affect the soil erodibility as well as soil erosion. Soil structure is one of the most important properties influencing runoff and soil loss because it determines the susceptibility of the aggregates to detach by either raindrop impacts or runoff shear stress. Many soil properties such as particle size distribution, organic matter, lime, gypsum, and exchangeable sodium percentage (ESP can affect the soil aggregation and the stability. Aggregates size distribution and their stability can be changed considerably because of agricultural practices. Information about variations of runoff and sediment in the rainfall events can be effective in modeling runoff as well as sediment. Thus, the study was conducted to determine runoff and sediment production of different aggregate sizes in the rainfall event scales. Materials and Methods: Toward the objective of the study, five aggregate classes consist of 0.25-2, 2-4.75, 4.75-5.6, 5.6-9.75, and 9.75-12.7 mm were collected from an agricultural sandy clay loam (0-30 cm using the related sieves in the field. Physicochemical soil analyses were performed in the aggregate samples using conventional methods in the lab. The aggregate samples were separately filed into fifteen flumes with a dimension of 50 cm × 100 cm and 15-cm in depth. The aggregate flumes were fixed on a steel plate with 9% slope and were exposed to the simulated rainfalls for investigating runoff and

  13. Legacy effects of anaerobic soil disinfestation on soil bacterial community composition and production of pathogen-suppressing volatiles

    NARCIS (Netherlands)

    Os, van G.J.; Agtmaal, van M.; Hol, G.; Hundscheid, M.P.J.; Runia, W.T.; Hordijk, C.; Boer, de W.

    2015-01-01

    There is increasing evidence that microbial volatiles (VOCs) play an important role in natural suppression of soil-borne diseases, but little is known on the factors that influence production of suppressing VOCs. In the current study we examined whether a stress-induced change in soil microbial

  14. Legacy effects of anaerobic soil disinfestation on soil bacterial community composition and production of pathogen-suppressing volatiles

    NARCIS (Netherlands)

    van Agtmaal, Maaike; van Os, Gera; Hol, Gera; Hundscheid, M.P.J.; Runia, Willemien; Hordijk, Cees; De Boer, Wietse

    2015-01-01

    BACKGROUND: There is increasing evidence that microbial volatiles (VOCs) play an important role in natural suppression of soil-borne diseases, but little is known on the factors that influence production of suppressing VOCs. In the current study we examined whether a stress-induced change in soil

  15. Efect of diferent rates of phosphorus and forms of application in the efficiency of triple superphosphate in a soil derived from volcanic ashes

    International Nuclear Information System (INIS)

    Pino, I.; Casas, L.

    1988-01-01

    Greenhouse experiments with a soil derived from volcanic ash were carried out in order to determine the efficiency of triple Superphosphate with different rates and forms of application. Oat (Avena Sativa L.) was used as reference crop. The P 32 labeled fertilizer was applied located 2,5 cm underneath the seeds. At the same time 500 mg P were applied located, mixed and in the surface of the soil. The P in the plant coming from the fertilizer was about 65%. This value was independent from the rates. The A value showed some fluctuations with the utmost rates of P. The fertilizer applied located and in the surface of the soil proved to be the most efficient form of application. The A value useful to compare the different treatments. The fertilizer efficiency was very low in both experiments, being the higher efficiency (5,9%) at the lowest rate which is not associated to a higher production. The best treatment was obtained with 500 mg of P located underneath the seed. (author)

  16. The economic production lot size model with several production rates

    DEFF Research Database (Denmark)

    Larsen, Christian

    should be chosen in the interval between the demand rate and the production rate, which minimize unit production costs, and should be used in an increasing order. Then, given the production rates, we derive closed form solutions for the optimal runtimes as well as the minimum average cost. Finally we...

  17. Forest floor and mineral soil respiration rates in a northern Minnesota red pine chronosequence

    Science.gov (United States)

    Powers, Matthew; Kolka, Randall; Bradford, John B.; Palik, Brian J.; Jurgensen, Martin

    2018-01-01

    We measured total soil CO2 efflux (RS) and efflux from the forest floor layers (RFF) in red pine (Pinus resinosaAit.) stands of different ages to examine relationships between stand age and belowground C cycling. Soil temperature and RS were often lower in a 31-year-old stand (Y31) than in 9-year-old (Y9), 61-year-old (Y61), or 123-year-old (Y123) stands. This pattern was most apparent during warm summer months, but there were no consistent differences in RFF among different-aged stands. RFF represented an average of 4–13% of total soil respiration, and forest floor removal increased moisture content in the mineral soil. We found no evidence of an age effect on the temperature sensitivity of RS, but respiration rates in Y61 and Y123 were less sensitive to low soil moisture than RS in Y9 and Y31. Our results suggest that soil respiration’s sensitivity to soil moisture may change more over the course of stand development than its sensitivity to soil temperature in red pine, and that management activities that alter landscape-scale age distributions in red pine forests could have significant impacts on rates of soil CO2 efflux from this forest type.

  18. Restoring Soil Quality to Mitigate Soil Degradation

    Directory of Open Access Journals (Sweden)

    Rattan Lal

    2015-05-01

    Full Text Available Feeding the world population, 7.3 billion in 2015 and projected to increase to 9.5 billion by 2050, necessitates an increase in agricultural production of ~70% between 2005 and 2050. Soil degradation, characterized by decline in quality and decrease in ecosystem goods and services, is a major constraint to achieving the required increase in agricultural production. Soil is a non-renewable resource on human time scales with its vulnerability to degradation depending on complex interactions between processes, factors and causes occurring at a range of spatial and temporal scales. Among the major soil degradation processes are accelerated erosion, depletion of the soil organic carbon (SOC pool and loss in biodiversity, loss of soil fertility and elemental imbalance, acidification and salinization. Soil degradation trends can be reversed by conversion to a restorative land use and adoption of recommended management practices. The strategy is to minimize soil erosion, create positive SOC and N budgets, enhance activity and species diversity of soil biota (micro, meso, and macro, and improve structural stability and pore geometry. Improving soil quality (i.e., increasing SOC pool, improving soil structure, enhancing soil fertility can reduce risks of soil degradation (physical, chemical, biological and ecological while improving the environment. Increasing the SOC pool to above the critical level (10 to 15 g/kg is essential to set-in-motion the restorative trends. Site-specific techniques of restoring soil quality include conservation agriculture, integrated nutrient management, continuous vegetative cover such as residue mulch and cover cropping, and controlled grazing at appropriate stocking rates. The strategy is to produce “more from less” by reducing losses and increasing soil, water, and nutrient use efficiency.

  19. Linking the distribution of carbon isotope ratios in soil carbonates and speleothems to climate conditions in the past: A model for the dependence of respiration rate on soil moisture

    Science.gov (United States)

    Liu, Y.; Ibarra, D. E.; Winnick, M.; Caves Rugenstein, J. K.; Oster, J. L.; Druhan, J. L.

    2017-12-01

    The carbon isotope compositions (δ13C) of atmospheric CO2, C3-origin organic carbon, and limestone epikarst differ substantially, resulting in variable δ13C signatures recorded in secondary soil carbonates and speleothems which represent a mixture of these sources. Even though this signal has been widely used in paleoclimate studies, the extent to which carbonate δ13C is influenced by the dynamic response of organic carbon respiration rates to soil moisture variations has yet to be fully evaluated [1]. Soils that are rewetted after a prolonged drought commonly display a peak in respiration rate followed by relaxation to a lower steady state in both lab incubation experiments and field observations. This transient behavior, known as the Birch effect, has been extensively observed across a broad range of locations and soil types, and may generate more than 50% of the total respired CO2 in some ecosystems [2]. Here, we seek to identify the influence of the Birch effect on carbonate δ13C records based on a moisture-dependent modeling approach. We report compiled respiration rates of soils from the literature and fit these data as a function of soil moisture, before imposing exponential dampening with depth and applying the resulting function in a production-diffusion equation [3]. We then implement a mass balance calculation for the δ13C value of carbonate precipitated from a mixture of atmospheric and respired CO2, including mass-dependent fractionation associated with diffusive transport. Our results offer a novel prediction for depth-resolved carbonate δ13C as a function of soil moisture, and suggest that Birch effect signals may be recorded in soil carbonates and influence the magnitude of carbonate δ13C variations in speleothems. Thus, we illustrate a prediction for the range of carbonate δ13C recorded in terrestrial carbonates and suggest that differences in the range of carbonate δ13C may indicate changes in soil moisture variability, providing a new

  20. Effects of animal activity on the absorption rate of soils in the ...

    African Journals Online (AJOL)

    The rates of absorption into various microsites in Karoo soils were compared. The absorption of water by hard, bare intershrub soils was significantly increased by the presence of emergence holes of adult cicadas and near nest-mounds of the harvester ant Messor capensis. Both these insects play an important role in ...

  1. Soil Properties and Plant Biomass Production in Natural Rangeland Management Systems

    Directory of Open Access Journals (Sweden)

    Romeu de Souza Werner

    Full Text Available ABSTRACT Improper management of rangelands can cause land degradation and reduce the economic efficiency of livestock activity. The aim of this study was to evaluate soil properties and quantify plant biomass production in four natural rangeland management systems in the Santa Catarina Plateau (Planalto Catarinense of Brazil. The treatments, which included mowed natural rangeland (NR, burned natural rangeland (BR, natural rangeland improved through the introduction of plant species after harrowing (IH, and natural rangeland improved through the introduction of plant species after chisel plowing (IC, were evaluated in a Nitossolo Bruno (Nitisol. In the improved treatments, soil acidity was corrected, phosphate fertilizer was applied, and intercropped annual ryegrass (Lolium multiflorum, velvet grass (Holcus lanatus, and white clover (Trifolium repens were sown. Management systems with harrowed or chisel plowed soil showed improved soil physical properties; however, the effect decreased over time and values approached those of burned and mowed natural rangelands. Natural rangeland systems in the establishment phase had little influence on soil organic C. The mowed natural rangeland and improved natural rangeland exhibited greater production of grazing material, while burning the field decreased production and increased the proportion of weeds. Improvement of the natural rangelands increased leguminous biomass for pasture.

  2. Study of natural radioactivity and 222Rn exhalation rate in soil samples for the assessment of average effective dose

    International Nuclear Information System (INIS)

    Bangotra, P.; Mehra, R.; Jakhu, R.; Sahoo, B.K

    2016-01-01

    The natural radioactivity in soil is usually determined from the 226 Ra (Radium), 232 Th (Thorium) and 40 K (potassium). 222 Rn and 220 Rn are produced in soil as a result of the presence of these radionuclides. As 226 Ra decay, the newly created 222 Rn radionuclide recoil from the parent grain and then exhale through the soil. Since 98.5% of radiological effects of 238 U series are produced by 226 Ra and its daughter products. The assessment of gamma radiation dose from natural sources is of particular importance as natural radiation is the largest contributor to the external dose of the world population. Authors are advised to maximize the information content utilizing the full space available. The main objective of the present study is to measure the level of natural radioactivity 226 Ra, 232 Th, 40 K and 222 Rn exhalation rate in the soil samples for health risk assessment

  3. The production rate of cosmogenic deuterium at the Moon's surface

    Science.gov (United States)

    Füri, Evelyn; Deloule, Etienne; Trappitsch, Reto

    2017-09-01

    The hydrogen (D/H) isotope ratio is a key tracer for the source of planetary water. However, secondary processes such as solar wind implantation and cosmic ray induced spallation reactions have modified the primordial D/H signature of 'water' in all rocks and soils recovered on the Moon. Here, we re-evaluate the production rate of cosmogenic deuterium (D) at the Moon's surface through ion microprobe analyses of hydrogen isotopes in olivines from eight Apollo 12 and 15 mare basalts. These in situ measurements are complemented by CO2 laser extraction-static mass spectrometry analyses of cosmogenic noble gas nuclides (3He, 21Ne, 38Ar). Cosmic ray exposure (CRE) ages of the mare basalts, derived from their cosmogenic 21Ne content, range from 60 to 422 Ma. These CRE ages are 35% higher, on average, than the published values for the same samples. The amount of D detected in the olivines increases linearly with increasing CRE ages, consistent with a production rate of (2.17 ± 0.11) ×10-12 mol(g rock)-1 Ma-1. This value is more than twice as high as previous estimates for the production of D by galactic cosmic rays, indicating that for water-poor lunar samples, i.e., samples with water concentrations ≤50 ppm, corrected D/H ratios have been severely overestimated.

  4. Role of Earthworms in Soil Fertility Maintenance through the Production of Biogenic Structures

    International Nuclear Information System (INIS)

    Bhadauria, T.; Saxena, K.G.

    2010-01-01

    The soil biota benefits soil productivity and contributes to the sustainable function of all ecosystems. The cycling of nutrients is a critical function that is essential to life on earth. Earthworms (EWs) are a major component of soil fauna communities in most ecosystems and comprise a large proportion of macro fauna biomass. Their activity is beneficial because it can enhance soil nutrient cycling through the rapid incorporation of detritus into mineral soils. In addition to this mixing effect, mucus production associated with water excretion in earthworm guts also enhances the activity of other beneficial soil microorganisms. This is followed by the production of organic matter. So, in the short term, a more significant effect is the concentration of large quantities of nutrients (N, P, K, and Ca) that are easily assimilable by plants in fresh cast depositions. In addition, earthworms seem to accelerate the mineralization as well as the turnover of soil organic matter. Earthworms are known also to increase nitrogen mineralization, through direct and indirect effects on the microbial community. The increased transfer of organic C and N into soil aggregates indicates the potential for earthworms to facilitate soil organic matter stabilization and accumulation in agricultural systems, and that their influence depends greatly on differences in land management practices. This paper summarises information on published data on the described subjects.

  5. Role of Earthworms in Soil Fertility Maintenance through the Production of Biogenic Structures

    Directory of Open Access Journals (Sweden)

    Tunira Bhadauria

    2010-01-01

    Full Text Available The soil biota benefits soil productivity and contributes to the sustainable function of all ecosystems. The cycling of nutrients is a critical function that is essential to life on earth. Earthworms (EWs are a major component of soil fauna communities in most ecosystems and comprise a large proportion of macrofauna biomass. Their activity is beneficial because it can enhance soil nutrient cycling through the rapid incorporation of detritus into mineral soils. In addition to this mixing effect, mucus production associated with water excretion in earthworm guts also enhances the activity of other beneficial soil microorganisms. This is followed by the production of organic matter. So, in the short term, a more significant effect is the concentration of large quantities of nutrients (N, P, K, and Ca that are easily assimilable by plants in fresh cast depositions. In addition, earthworms seem to accelerate the mineralization as well as the turnover of soil organic matter. Earthworms are known also to increase nitrogen mineralization, through direct and indirect effects on the microbial community. The increased transfer of organic C and N into soil aggregates indicates the potential for earthworms to facilitate soil organic matter stabilization and accumulation in agricultural systems, and that their influence depends greatly on differences in land management practices. This paper summarises information on published data on the described subjects.

  6. Nitrogen loss from grassland on peat soils through nitrous oxide production.

    NARCIS (Netherlands)

    Koops, J.G.; Beusichem, van M.L.; Oenema, O.

    1997-01-01

    Nitrous oxide (N2O) in soils is produced through nitrification and denitrification. The N2O produced is considered as a nitrogen (N) loss because it will most likely escape from the soil to the atmosphere as N2O or N2. Aim of the study was to quantify N2O production in grassland on peat soils in

  7. Trophic structure and feeding rates of forest soil invertebrate populations

    Energy Technology Data Exchange (ETDEWEB)

    McBrayer, J F; Reichle, D E

    1971-01-01

    Trophic level relationships of a soil invertebrate community were determined using the transient behavior of cesium-137 in experimental soil microcosms. Feeding rates were estimated from radionuclide mass balance equations using radiocesium uptake coefficients, equilibrium concentrations of /sup 137/Cs in consumers, and /sup 137/Cs composition of food bases. The fungivore trophic level included Scatopsidae larvae (Diptera), Enchytraeida (Annelida), Entomobryidae and Onychiuridae (Collembola), Rhodacaridae (Mesostigmata), and Oribatulidae, Camasiidae, Carabodidae, and Cymbaeremaeidae (Oribatei). Approximately 60% of the total faunal biomass occurred in the fungivore trophic level. Fungivores averaged 7.0 +/- 2.4% dry body weight ingested per day. Cecidomyiidae larvae (Diptera), Diplopoda, Isotomidae (Collembola), Uropodina, and Phthiracaridae (Oribatei) were determined to be surface-feeding saprophages. Subsurface-feeding saprophages included Symphyla, Cillibidae (Uropidina), and Palaeacaridae and Epilohmannidae (Oribatei). Surface-feeding saprophages averaged 1.0 +/- 0.4% dry body weight ingested per day. Feeding rates were not calculated for saprophages feeding within the mineral soil horizon. Predators included Dolichopodidae larvae (Diptera), gamasine mites, and the Scutacaridae and other prostigmatid mites. Predators averaged 2.5 +/- 1.0% dry body weight ingested per day. 15 references, 3 figures, 3 tables.

  8. Brief and vigorous N2O production by soil at spring thaw

    DEFF Research Database (Denmark)

    Christensen, Søren; Tiedje, James M.

    1990-01-01

    In an acid sandy loam soil (pH 3.8), field production of N2O was two orders of magnitude higher at thaw in the spring than at any time during the rest of the year. Soil thaw in midwinter did not result in any increase in N2O flux. Soil water content remained at, or above field capacity during...... measurements; nitrate was added in excess. This effect could be reproduced in the laboratory: thawing soil cores at controlled temperature, nitrate and moisture yielded a large flush of N2O compared to an unfrozen control. The results indicate the importance of microbial N2O production during thaw for total...

  9. Analysis of physical properties controlling steady-state infiltration rates on tropical savannah soils

    International Nuclear Information System (INIS)

    Mbagwu, J.S.C.

    1993-10-01

    A knowledge of physical properties influencing the steady-state infiltration rates (ic) of soils is needed for the hydrologic modelling of the infiltration process. In this study evidence is provided to show that effective porosity (Pe) (i.e. the proportion of macro pore spaces with equivalent radius of > 15 μm) and dry bulk density are the most important soil physical properties controlling the steady-state infiltration rates on a tropical savannah with varying land use histories. At a macro porosity value of ≤ 5.0% the steady-state infiltration rate is zero. Total porosity and the proportion of water-retaining pores explained only a small fraction of the variation in this property. Steady-state infiltration rates can also be estimated from either the saturated hydraulic conductivity (Ks) by the equation, i c = 31.1 + 1.06 (Ks), (R 2 = 0.8104, p ≤ 0.001) or the soil water transmissivity (A) by the equation, i c = 30.0 + 29.9(A), (R 2 = 0.8228, ρ ≤ 0.001). The Philip two-parameter model under predicted steady-state infiltration rates generally. Considering the ease of determination and reliability it is suggested that effective porosity be used to estimate the steady-state infiltration rates of these other soils with similar characteristics. The model is, i c 388.7(Pe) - 10.8(R 2 = 0.7265, p ≤ 0.001) where i c is in (cm/hr) and Pe in (cm 3 /cm 3 ). (author). 20 refs, 3 figs, 4 tabs

  10. A comparison of measured and calculated values of air kerma rates from 137Cs in soil

    Directory of Open Access Journals (Sweden)

    V. P. Ramzaev

    2015-01-01

    Full Text Available In 2010, a study was conducted to determine the air gamma dose rate from 137Cs deposited in soil. The gamma dose rate measurements and soil sampling were performed at 30 reference plots from the south-west districts of the Bryansk region (Russia that had been heavily contaminated as a result of the Chernobyl accident. The 137Cs inventory in the top 20 cm of soil ranged from 260 kBq m–2 to 2800 kBq m–2. Vertical distributions of 137Cs in soil cores (6 samples per a plot were determined after their sectioning into ten horizontal layers of 2 cm thickness. The vertical distributions of 137Cs in soil were employed to calculate air kerma rates, K, using two independent methods proposed by Saito and Jacob [Radiat. Prot. Dosimetry, 1995, Vol. 58, P. 29–45] and Golikov et al. [Contaminated Forests– Recent Developments in Risk Identification and Future Perspective. Kluwer Academic Publishers, 1999. – P. 333–341]. A very good coincidence between the methods was observed (Spearman’s rank coefficient of correlation = 0.952; P<0.01; on average, a difference between the kerma rates calculated with two methods did not exceed 3%. The calculated air kerma rates agreed with the measured dose rates in air very well (Spearman’s coefficient of correlation = 0.952; P<0.01. For large grassland plots (n=19, the measured dose rates were on average 6% less than the calculated kerma rates. The tested methods for calculating the air dose rate from 137Cs in soil can be recommended for practical studies in radiology and radioecology. 

  11. A global analysis of fine root production as affected by soil nitrogen and phosphorus.

    Science.gov (United States)

    Yuan, Z Y; Chen, Han Y H

    2012-09-22

    Fine root production is the largest component of belowground production and plays substantial roles in the biogeochemical cycles of terrestrial ecosystems. The increasing availability of nitrogen (N) and phosphorus (P) due to human activities is expected to increase aboveground net primary production (ANNP), but the response of fine root production to N and P remains unclear. If roots respond to nutrients as ANNP, fine root production is anticipated to increase with increasing soil N and P. Here, by synthesizing data along the nutrient gradient from 410 natural habitats and from 469 N and/or P addition experiments, we showed that fine root production increased in terrestrial ecosystems with an average increase along the natural N gradient of up to 0.5 per cent with increasing soil N. Fine root production also increased with soil P in natural conditions, particularly at P production increased by a global average of 27, 21 and 40 per cent, respectively. However, its responses differed among ecosystems and soil types. The global average increases in fine root production are lower than those of ANNP, indicating that above- and belowground counterparts are coupled, but production allocation shifts more to aboveground with higher soil nutrients. Our results suggest that the increasing fertilizer use and combined N deposition at present and in the future will stimulate fine root production, together with ANPP, probably providing a significant influence on atmospheric CO(2) emissions.

  12. Sorption and biodegradation characteristics of the selected pharmaceuticals and personal care products onto tropical soil.

    Science.gov (United States)

    Foolad, Mahsa; Hu, Jiangyong; Tran, Ngoc Han; Ong, Say Leong

    2016-01-01

    In the present study, the sorption and biodegradation characteristics of five pharmaceutical and personal care products (PPCPs), including acetaminophen (ACT), carbamazepine (CBZ), crotamiton (CTMT), diethyltoluamide (DEET) and salicylic acid (SA), were studied in laboratory-batch experiments. Sorption kinetics experimental data showed that sorption systems under this study were more appropriately described by the pseudo second-order kinetics with a correlation coefficient (R2)>0.98. Sorption equilibrium data of almost all target compounds onto soil could be better described by the Freundlich sorption isotherm model. The adsorption results showed higher soil affinity for SA, following by ACT. Results also indicated a slight effect of pH on PPCP adsorption with lower pH causing lower adsorption of compounds onto the soil except for SA at pH 12. Moreover, adsorption of PPCPs onto the soil was influenced by natural organic matter (NOM) since the higher amount of NOM caused lower adsorption to the soil. Biodegradation studies of selected PPCPs by indigenous microbial community present in soil appeared that the removal rates of ACT, SA and DEET increased with time while no effect had been observed for the rest. This study suggests that the CBZ and CTMT can be considered as suitable chemical sewage indicators based on their low sorption affinity and high resistance to biodegradation.

  13. Prediction of terrestrial gamma dose rate based on geological formations and soil types in the Johor State, Malaysia.

    Science.gov (United States)

    Saleh, Muneer Aziz; Ramli, Ahmad Termizi; bin Hamzah, Khaidzir; Alajerami, Yasser; Moharib, Mohammed; Saeed, Ismael

    2015-10-01

    This study aims to predict and estimate unmeasured terrestrial gamma dose rate (TGDR) using statistical analysis methods to derive a model from the actual measurement based on geological formation and soil type. The measurements of TGDR were conducted in the state of Johor with a total of 3873 measured points which covered all geological formations, soil types and districts. The measurements were taken 1 m above the soil surface using NaI [Ti] detector. The measured gamma dose rates ranged from 9 nGy h(-1) to 1237 nGy h(-1) with a mean value of 151 nGy h(-1). The data have been normalized to fit a normal distribution. Tests of significance were conducted among all geological formations and soil types, using the unbalanced one way ANOVA. The results indicated strong significant differences due to the different geological formations and soil types present in Johor State. Pearson Correlation was used to measure the relations between gamma dose rate based on geological formation and soil type (D(G,S)) with the gamma dose rate based on geological formation (D(G)) or soil type (D(s)). A very good correlation was found between D(G,S) and D(G) or D(G,S) and D(s). A total of 118 pairs of geological formations and soil types were used to derive the statistical contribution of geological formations and soil types to gamma dose rates. The contribution of the gamma dose rate from geological formation and soil type were found to be 0.594 and 0.399, respectively. The null hypotheses were accepted for 83% of examined data, therefore, the model could be used to predict gamma dose rates based on geological formation and soil type information. Copyright © 2015 Elsevier Ltd. All rights reserved.

  14. Measurement of radon exhalation rate in various building materials and soil samples

    Science.gov (United States)

    Bala, Pankaj; Kumar, Vinod; Mehra, Rohit

    2017-03-01

    Indoor radon is considered as one of the potential dangerous radioactive elements. Common building materials and soil are the major source of this radon gas in the indoor environment. In the present study, the measurement of radon exhalation rate in the soil and building material samples of Una and Hamirpur districts of Himachal Pradesh has been done with solid state alpha track detectors, LR-115 type-II plastic track detectors. The radon exhalation rate for the soil samples varies from 39.1 to 91.2 mBq kg-1 h-1 with a mean value 59.7 mBq kg-1 h-1. Also the radium concentration of the studied area is found and it varies from 30.6 to 51.9 Bq kg-1 with a mean value 41.6 Bq kg-1. The exhalation rate for the building material samples varies from 40.72 (sandstone) to 81.40 mBq kg-1 h-1 (granite) with a mean value of 59.94 mBq kg-1 h-1.

  15. Soil quality assessment in rice production systems: establishing a minimum data set.

    NARCIS (Netherlands)

    Rodrigues de Lima, A.C.; Hoogmoed, W.B.; Brussaard, L.

    2008-01-01

    Soil quality, as a measure of the soil's capacity to function, can be assessed by indicators based on physical, chemical, and biological properties. Here we report on the assessment of soil quality in 21 rice (Oryza sativa) fields under three rice production systems (semi-direct, pre-germinated, and

  16. Assessing soil erosion rates for a large catchment in the Central Highlands of Vietnam using fallout radionuclides

    International Nuclear Information System (INIS)

    Phan Son Hai; Nguyen Thanh Binh; Nguyen Minh Dao; Nguyen Thi Huong Lan; Nguyen Thi Mui; Le Xuan Thang; Phan Quang Trung; Trinh Cong Tu; Tran Tien Dung

    2014-01-01

    Fallout radionuclides Be-7 and Cs-137 were applied to assess soil erosion rates for a 270.5 km 2 catchment with a variety of slope (from 0 o to more than 45 o , crops or vegetation (natural forest, artificial forest, perennial crops, annual crops) and a variety of tillage and soil conservation measures. Soil erosion rates were estimated at 90 areas within the catchment. Each sampling area has at least one feature of the slope, rainfall, crops, farming practice different from others. Soil erosion rates in this region depend significantly on the slope, crops and farming techniques. Averaging over crops, soil erosion rates by slopes 0 - 5 o , 5 - 15 o , 15 - 25 o and 25 - 35 o are 5.0, 12.8, 18.9 and 21.3 t.ha -1 .y -1 , respectively. Forest land has the least soil erosion rates, ranging between 0.5 t.ha -1 .y -1 and 14 t.ha -1 .y -1 depending on the slope. Annual crops land has the highest soil erosion rates, ranging between 6 t.ha -1 .y -1 and 42 t.ha -1 .y -1 when slope varies from < 5 o to 32 o . Perennial crop land has soil erosion rates in the range of 5 t.ha -1 .y -1 and 39 t.ha -1 .y -1 . In areas with the same slope, the soil erosion rate is the highest for cashew plantations, lower for mulberry field and the lowest for tea or coffee plantations. Soil erosion has resulted in losing a significant quantity of plant nutrients such as OM, N, P 2 O 5 and K 2 O every year. Generally, lost nutrient quantities due to soil erosion are proportional to erosion rates. Some areas of annual crop land lost a large amount of nutrients every year, up to 1435 kg OM, 79 kg N, 54 kg P 2 O 5 and 36 kg K 2 O. Similarly, perennial crop lands in this region could lost up to 1736 kg OM, 91 kg N, 66 kg P 2 O 5 and 40 kg K 2 O every year. Owing to soil erosion, the catchment has lost about 211200 tons of surface soil per year during last 50 years, corresponding to the rate of 7.8 t.ha -1 .y -1 . This amount of eroded soil was deposited in drainage of the catchment and in reservoirs

  17. Biochar Decelerates Soil Organic Nitrogen Cycling but Stimulates Soil Nitrification in a Temperate Arable Field Trial

    Science.gov (United States)

    Prommer, Judith; Wanek, Wolfgang; Hofhansl, Florian; Trojan, Daniela; Offre, Pierre; Urich, Tim; Schleper, Christa; Sassmann, Stefan; Kitzler, Barbara; Soja, Gerhard; Hood-Nowotny, Rebecca Clare

    2014-01-01

    Biochar production and subsequent soil incorporation could provide carbon farming solutions to global climate change and escalating food demand. There is evidence that biochar amendment causes fundamental changes in soil nutrient cycles, often resulting in marked increases in crop production, particularly in acidic and in infertile soils with low soil organic matter contents, although comparable outcomes in temperate soils are variable. We offer insight into the mechanisms underlying these findings by focusing attention on the soil nitrogen (N) cycle, specifically on hitherto unmeasured processes of organic N cycling in arable soils. We here investigated the impacts of biochar addition on soil organic and inorganic N pools and on gross transformation rates of both pools in a biochar field trial on arable land (Chernozem) in Traismauer, Lower Austria. We found that biochar increased total soil organic carbon but decreased the extractable organic C pool and soil nitrate. While gross rates of organic N transformation processes were reduced by 50–80%, gross N mineralization of organic N was not affected. In contrast, biochar promoted soil ammonia-oxidizer populations (bacterial and archaeal nitrifiers) and accelerated gross nitrification rates more than two-fold. Our findings indicate a de-coupling of the soil organic and inorganic N cycles, with a build-up of organic N, and deceleration of inorganic N release from this pool. The results therefore suggest that addition of inorganic fertilizer-N in combination with biochar could compensate for the reduction in organic N mineralization, with plants and microbes drawing on fertilizer-N for growth, in turn fuelling the belowground build-up of organic N. We conclude that combined addition of biochar with fertilizer-N may increase soil organic N in turn enhancing soil carbon sequestration and thereby could play a fundamental role in future soil management strategies. PMID:24497947

  18. Biochar decelerates soil organic nitrogen cycling but stimulates soil nitrification in a temperate arable field trial.

    Directory of Open Access Journals (Sweden)

    Judith Prommer

    Full Text Available Biochar production and subsequent soil incorporation could provide carbon farming solutions to global climate change and escalating food demand. There is evidence that biochar amendment causes fundamental changes in soil nutrient cycles, often resulting in marked increases in crop production, particularly in acidic and in infertile soils with low soil organic matter contents, although comparable outcomes in temperate soils are variable. We offer insight into the mechanisms underlying these findings by focusing attention on the soil nitrogen (N cycle, specifically on hitherto unmeasured processes of organic N cycling in arable soils. We here investigated the impacts of biochar addition on soil organic and inorganic N pools and on gross transformation rates of both pools in a biochar field trial on arable land (Chernozem in Traismauer, Lower Austria. We found that biochar increased total soil organic carbon but decreased the extractable organic C pool and soil nitrate. While gross rates of organic N transformation processes were reduced by 50-80%, gross N mineralization of organic N was not affected. In contrast, biochar promoted soil ammonia-oxidizer populations (bacterial and archaeal nitrifiers and accelerated gross nitrification rates more than two-fold. Our findings indicate a de-coupling of the soil organic and inorganic N cycles, with a build-up of organic N, and deceleration of inorganic N release from this pool. The results therefore suggest that addition of inorganic fertilizer-N in combination with biochar could compensate for the reduction in organic N mineralization, with plants and microbes drawing on fertilizer-N for growth, in turn fuelling the belowground build-up of organic N. We conclude that combined addition of biochar with fertilizer-N may increase soil organic N in turn enhancing soil carbon sequestration and thereby could play a fundamental role in future soil management strategies.

  19. Biochar decelerates soil organic nitrogen cycling but stimulates soil nitrification in a temperate arable field trial.

    Science.gov (United States)

    Prommer, Judith; Wanek, Wolfgang; Hofhansl, Florian; Trojan, Daniela; Offre, Pierre; Urich, Tim; Schleper, Christa; Sassmann, Stefan; Kitzler, Barbara; Soja, Gerhard; Hood-Nowotny, Rebecca Clare

    2014-01-01

    Biochar production and subsequent soil incorporation could provide carbon farming solutions to global climate change and escalating food demand. There is evidence that biochar amendment causes fundamental changes in soil nutrient cycles, often resulting in marked increases in crop production, particularly in acidic and in infertile soils with low soil organic matter contents, although comparable outcomes in temperate soils are variable. We offer insight into the mechanisms underlying these findings by focusing attention on the soil nitrogen (N) cycle, specifically on hitherto unmeasured processes of organic N cycling in arable soils. We here investigated the impacts of biochar addition on soil organic and inorganic N pools and on gross transformation rates of both pools in a biochar field trial on arable land (Chernozem) in Traismauer, Lower Austria. We found that biochar increased total soil organic carbon but decreased the extractable organic C pool and soil nitrate. While gross rates of organic N transformation processes were reduced by 50-80%, gross N mineralization of organic N was not affected. In contrast, biochar promoted soil ammonia-oxidizer populations (bacterial and archaeal nitrifiers) and accelerated gross nitrification rates more than two-fold. Our findings indicate a de-coupling of the soil organic and inorganic N cycles, with a build-up of organic N, and deceleration of inorganic N release from this pool. The results therefore suggest that addition of inorganic fertilizer-N in combination with biochar could compensate for the reduction in organic N mineralization, with plants and microbes drawing on fertilizer-N for growth, in turn fuelling the belowground build-up of organic N. We conclude that combined addition of biochar with fertilizer-N may increase soil organic N in turn enhancing soil carbon sequestration and thereby could play a fundamental role in future soil management strategies.

  20. Prediction of terrestrial gamma dose rate based on geological formations and soil types in the Johor State, Malaysia

    International Nuclear Information System (INIS)

    Saleh, Muneer Aziz; Ramli, Ahmad Termizi; Hamzah, Khaidzir bin; Alajerami, Yasser; Moharib, Mohammed; Saeed, Ismael

    2015-01-01

    This study aims to predict and estimate unmeasured terrestrial gamma dose rate (TGDR) using statistical analysis methods to derive a model from the actual measurement based on geological formation and soil type. The measurements of TGDR were conducted in the state of Johor with a total of 3873 measured points which covered all geological formations, soil types and districts. The measurements were taken 1 m above the soil surface using NaI [Ti] detector. The measured gamma dose rates ranged from 9 nGy h −1 to 1237 nGy h −1 with a mean value of 151 nGy h −1 . The data have been normalized to fit a normal distribution. Tests of significance were conducted among all geological formations and soil types, using the unbalanced one way ANOVA. The results indicated strong significant differences due to the different geological formations and soil types present in Johor State. Pearson Correlation was used to measure the relations between gamma dose rate based on geological formation and soil type (D G,S ) with the gamma dose rate based on geological formation (D G ) or soil type (D s ). A very good correlation was found between D G,S and D G or D G,S and D s . A total of 118 pairs of geological formations and soil types were used to derive the statistical contribution of geological formations and soil types to gamma dose rates. The contribution of the gamma dose rate from geological formation and soil type were found to be 0.594 and 0.399, respectively. The null hypotheses were accepted for 83% of examined data, therefore, the model could be used to predict gamma dose rates based on geological formation and soil type information. - Highlights: • A very good correlation coefficient was found between D G,S and D G or D G,S and D s . • The contribution of the gamma dose rate from geological formation (GDR) is 0.594. • The contribution of the GDR from soil type was found to be 0.399. • A 83% of examined data were accepted the null hypotheses. • The model

  1. No diurnal variation in rate or carbon isotope composition of soil respiration in a boreal forest

    International Nuclear Information System (INIS)

    Betson, N.R.; Gottlicher, S.G.; Hogberg, P.; Hall, M.; Wallin, G.; Richter, A.

    2007-01-01

    This study evaluated the diurnal variability in the rate and stable carbon isotope ratio ((delta) 13 C) of soil respiration in a northern boreal forest, measured with opaque chambers after the removal of understory vegetation. The experiment was conducted in June and August 2004 at the Picea abies L. Karst-dominated Flakaliden Research Forest in northern Sweden, using unfertilized girdled-tree plots and unfertilized non-girdled tree plots. Soil respiration and (delta) 13 C of soil-respired carbon dioxide (CO 2 ) were measured every 4 hours on 6 plots, with a total of 11 sampling times over each 48 hour period. The purpose was to clarify an earlier study regarding the origin of diurnal patterns of soil CO 2 flux. This study explored whether the diurnal patterns were the result of photosynthetic CO 2 uptake during the day by the understory or whether there were underlying trends in soil respiration driven by plant root allocation. The sampling campaigns undertaken in this study investigated whether diurnal variations in soil respiration rate and (delta) 13 C exist in this ecosystem when no understory vegetation is present. Shoot photosynthesis and environmental parameters were measured simultaneously. Despite significant variations in climatic conditions and shoot photosynthetic rates in non-girdled trees, no diurnal patterns in soil respiration rates and (delta) 13 C were noted in either treatment. The lack of detectable diurnal changes in both treatments indicates that modeling of daily boreal forest carbon balances based on single instantaneous measurements are unlikely to be misconstrued by substantial diurnal trends. However, it was suggested that spatial variable should be accounted for, given the large standard errors. The impact of tree girdling on soil respiration rates also emphasized the significance of canopy photosynthesis in driving soil processes. 37 refs., 2 figs

  2. Preliminary assessment of the potential for using cesium-137 technique to estimate rates of soil erosion on cultivated land in La Victoria I, Camaguey province of cuba

    International Nuclear Information System (INIS)

    Brigido, F.O.; Gandarilla Benitez, J.E.

    1999-01-01

    Despite a growing awareness that erosion on cultivated land in Cuba is a potential hazard to long term productivity, there is still only limited information on the rates involved, particularly long term values. The potential for using the radionuclide Caesium-137 as an environmental tracer to indicate sources of soil erosion on cultivated soils in La Victoria catchment is introduced. Use of Caesium-137 measurements to estimate rates of erosion and deposition is founded on comparison of the Caesium-137 inventories at individual sampling points with a reference inventory representing the local Caesium fallout input and thus the inventory to be expected at the site experiencing neither erosion nor deposition. Two models for converting Caesium-137 measurements to estimates of soil redistribution rates on studied site have been used, the Proportional Model and Mass Balance Model. Using the first one net soil erosion was calculated to be 17.6 t. Ha 1 - .year 1 - . Estimates of soil loss using a Mass Balance Model (Simplified Model 1 and Model 2) were found to be 30.2 and 30.6 t. Ha 1 - .year 1 - ,respectively. Preliminary results suggest that Caesium-137 technique may be of considerable value in assembling data on the rates and spatial distribution of soil loss and a reliable tool for developing of soil conservation program

  3. Application of Microbial Products to Promote Electrodialytic Remediation of Heavy Metal Contaminated Soil

    DEFF Research Database (Denmark)

    Jensen, Pernille Erland

    2006-01-01

    remediation (EDR) method for efficient treatment of Pb-contaminated soil by application of microbial products. Mobilization of Pb in soil by complexation with exopolymers and whole or disintegrated cells was investigated in column studies. Although exopolymers were previously shown to mobilize Pb in soil...... as potential methods for promotion of EDR of Pb contaminated soil. By these methods mobilization of Pb would occur due to complexation with much smaller substances than the previously examined and rejected exopolymers, why they were considered more efficient for mobilization of Pb in an electric current field...... also rejected, primarily due to the insufficient concentrations produced by microorganisms in general and the unrealistic high costs of industrially produced siderophores in relation to the low value of the product to be treated. Furthermore no detection of siderophore production was possible during...

  4. Bioenergy by-products as soil amendments? Implications for carbon sequestration and greenhuise gas emissions

    NARCIS (Netherlands)

    Cayuela, M.L.; Oenema, O.; Kuikman, P.J.; Bakker, R.R.; Groenigen, van J.W.

    2010-01-01

    An important but little understood aspect of bioenergy production is its overall impact on soil carbon (C) and nitrogen (N) cycling. Increased energy production from biomass will inevitably lead to higher input of its by-products to the soil as amendments or fertilizers. However, it is still unclear

  5. Interpretation of soil-type maps of forestry in terms of terrestrial gamma-ray dose rate

    International Nuclear Information System (INIS)

    Kopp, D.; Hannemann, M.

    1984-01-01

    Measurements have been performed in the lowlands of the G.D.R. to determine the activity concentration of 40 K, 226 Ra and 232 Th in soil as well as the terrestrial γ-ray dose rate at the soil surface and 1 m above. The results demonstrate that the dose rate due to terrestrial radiation can be assessed by means of forest site maps indicating the potassium content of the various soils. Two examples were presented to explain the approach. (author)

  6. Gasification biochar as a valuable by-product for carbon sequestration and soil amendment

    International Nuclear Information System (INIS)

    Hansen, Veronika; Müller-Stöver, Dorette; Ahrenfeldt, Jesper; Holm, Jens Kai; Henriksen, Ulrik Birk; Hauggaard-Nielsen, Henrik

    2015-01-01

    Thermal gasification of various biomass residues is a promising technology for combining bioenergy production with soil fertility management through the application of the resulting biochar as soil amendment. In this study, we investigated gasification biochar (GB) materials originating from two major global biomass fuels: straw gasification biochar (SGB) and wood gasification biochar (WGB), produced by a Low Temperature Circulating Fluidized Bed gasifier (LT-CFB) and a TwoStage gasifier, respectively, optimized for energy conversion. Stability of carbon in GB against microbial degradation was assessed in a short-term soil incubation study and compared to the traditional practice of direct incorporation of cereal straw. The GBs were chemically and physically characterized to evaluate their potential to improve soil quality parameters. After 110 days of incubation, about 3% of the added GB carbon was respired as CO 2 , compared to 80% of the straw carbon added. The stability of GB was also confirmed by low H/C and O/C atomic ratios with lowest values for WGB (H/C 0.12 and O/C 0.10). The soil application of GBs exhibited a liming effect increasing the soil pH from ca 8 to 9. Results from scanning electron microscopy and BET analyses showed high porosity and specific surface area of both GBs, indicating a high potential to increase important soil quality parameters such as soil structure, nutrient and water retention, especially for WGB. These results seem promising regarding the possibility to combine an efficient bioenergy production with various soil aspects such as carbon sequestration and soil quality improvements. - Highlights: • Biomass gasification can combine efficient bioenergy production with valuable biochar residuals for soil improvements. • The two investigated gasification biochars are recalcitrant indicating soil carbon sequestration potential. • Gasification biochars are potential soil improvers due to high specific surface area, liming effect

  7. Effects of soil management techniques on soil water erosion in apricot orchards.

    Science.gov (United States)

    Keesstra, Saskia; Pereira, Paulo; Novara, Agata; Brevik, Eric C; Azorin-Molina, Cesar; Parras-Alcántara, Luis; Jordán, Antonio; Cerdà, Artemi

    2016-05-01

    Soil erosion is extreme in Mediterranean orchards due to management impact, high rainfall intensities, steep slopes and erodible parent material. Vall d'Albaida is a traditional fruit production area which, due to the Mediterranean climate and marly soils, produces sweet fruits. However, these highly productive soils are left bare under the prevailing land management and marly soils are vulnerable to soil water erosion when left bare. In this paper we study the impact of different agricultural land management strategies on soil properties (bulk density, soil organic matter, soil moisture), soil water erosion and runoff, by means of simulated rainfall experiments and soil analyses. Three representative land managements (tillage/herbicide/covered with vegetation) were selected, where 20 paired plots (60 plots) were established to determine soil losses and runoff. The simulated rainfall was carried out at 55mmh(-1) in the summer of 2013 (soil moisture) for one hour on 0.25m(2) circular plots. The results showed that vegetation cover, soil moisture and organic matter were significantly higher in covered plots than in tilled and herbicide treated plots. However, runoff coefficient, total runoff, sediment yield and soil erosion were significantly higher in herbicide treated plots compared to the others. Runoff sediment concentration was significantly higher in tilled plots. The lowest values were identified in covered plots. Overall, tillage, but especially herbicide treatment, decreased vegetation cover, soil moisture, soil organic matter, and increased bulk density, runoff coefficient, total runoff, sediment yield and soil erosion. Soil erosion was extremely high in herbicide plots with 0.91Mgha(-1)h(-1) of soil lost; in the tilled fields erosion rates were lower with 0.51Mgha(-1)h(-1). Covered soil showed an erosion rate of 0.02Mgha(-1)h(-1). These results showed that agricultural management influenced water and sediment dynamics and that tillage and herbicide

  8. Sugarcane productivity correlated with physical-chemical attributes to create soil management zone

    Directory of Open Access Journals (Sweden)

    Flávio Carlos Dalchiavon

    2013-10-01

    Full Text Available The socioeconomic importance of sugar cane in Brazil is unquestionable because it is the raw material for the production of ethanol and sugar. The accurate spatial intervention in the management of the crop, resulting zones of soil management, increases productivity as well as its agricultural yields. The spatial and Person's correlations between sugarcane attributes and physico-chemical attributes of a Typic Tropustalf were studied in the growing season of 2009, in Suzanápolis, State of São Paulo, Brazil (20°28'10'' S lat.; 50°49'20'' W long., in order to obtain the one that best correlates with agricultural productivity. Thus, the geostatistical grid with 120 sampling points was installed to soil and data collection in a plot of 14.6 ha with second crop sugarcane. Due to their substantial and excellent linear and spatial correlations with the productivity of the sugarcane, the population of plants and the organic matter content of the soil, by evidencing substantial correlations, linear and spatial, with the productivity of sugarcane, were indicators of management zones strongly attached to such productivity.

  9. Radon mass exhalation rate in soil samples at South Bengaluru city, Karnataka, India

    International Nuclear Information System (INIS)

    Poojitha, C.G.; Pranesha, T.S.; Ganesh, K.E.; Sahoo, B.K.; Sapra, B.K.

    2017-01-01

    Radon mass exhalation rate in soil samples collected from different locations of South Bengaluru city were measured using scintillation based Smart radon thoron monitor (RnDuo). It has been observed that the mass exhalation rate estimated due to presence of radon concentration in soil samples ranges from 39.18 - 265.58 mBq/kg/h with an average value of 115.64 mBq/kg/h. Finally we compare our results with similar investigation from different parts of India. (author)

  10. Immobilizer-assisted management of metal-contaminated agricultural soils for safer food production.

    Science.gov (United States)

    Kim, Kwon-Rae; Kim, Jeong-Gyu; Park, Jeong-Sik; Kim, Min-Suk; Owens, Gary; Youn, Gyu-Hoon; Lee, Jin-Su

    2012-07-15

    Production of food crops on metal contaminated agricultural soils is of concern because consumers are potentially exposed to hazardous metals via dietary intake of such crops or crop derived products. Therefore, the current study was conducted to develop management protocols for crop cultivation to allow safer food production. Metal uptake, as influenced by pH change-induced immobilizing agents (dolomite, steel slag, and agricultural lime) and sorption agents (zeolite and compost), was monitored in three common plants representative of leafy (Chinese cabbage), root (spring onion) and fruit (red pepper) vegetables, in a field experiment. The efficiency of the immobilizing agents was assessed by their ability to decrease the phytoavailability of metals (Cd, Pb, and Zn). The fruit vegetable (red pepper) showed the least accumulation of Cd (0.16-0.29 mgkg(-1) DW) and Pb (0.2-0.9 mgkg(-1) DW) in edible parts regardless of treatment, indicating selection of low metal accumulating crops was a reasonable strategy for safer food production. However, safer food production was more likely to be achievable by combining crop selection with immobilizing agent amendment of soils. Among the immobilizing agents, pH change-induced immobilizers were more effective than sorption agents, showing decreases in Cd and Pb concentrations in each plant well below standard limits. The efficiency of pH change-induced immobilizers was also comparable to reductions obtained by 'clean soil cover' where the total metal concentrations of the plow layer was reduced via capping the surface with uncontaminated soil, implying that pH change-induced immobilizers can be practically applied to metal contaminated agricultural soils for safer food production. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Monitoring the Perturbation of Soil and Groundwater Microbial Communities Due to Pig Production Activities

    KAUST Repository

    Hong, Pei-Ying; Yannarell, A. C.; Dai, Q.; Ekizoglu, M.; Mackie, R. I.

    2013-01-01

    This study aimed to determine if biotic contaminants originating from pig production farms are disseminated into soil and groundwater microbial communities. A spatial and temporal sampling of soil and groundwater in proximity to pig production farms

  12. Atmospheric production rate of 36Cl

    International Nuclear Information System (INIS)

    Parrat, Y.; Hajdas, W.; Baltensperger, U.; Synal, H.A.; Kubik, P.W.; Gaeggeler, H.W.; Suter, M.

    1997-01-01

    Using experimental cross sections, a new calculation of the atmospheric production rate of 36 Cl was carried out. A mean production rate of 20 atoms m -2 s -1 was obtained, which is lower than mean 36 Cl deposition rates. (author) 2 figs., 7 refs

  13. Natural radioactivity and radon exhalation rate of soil in southern Egypt

    International Nuclear Information System (INIS)

    Sroor, A.; El-Bahi, S.M.; Ahmed, F.; Abdel-Haleem, A.S.

    2001-01-01

    The level of natural radioactivity in soil of 30 mining samples collected from six locations in southern Egypt was measured. Concentrations of radionuclides in samples were determined by γ-ray spectrometer using HPGe detector with a specially designed shield. The obtained results of uranium and thorium series as well as potassium (K-40) are discussed. The present data were compared with data obtained from different areas in Egypt. Also, a solid state nuclear track detector SSNTD (Cr-39) was used to measure the radon concentration as well as exhalation rate for these samples. The radon concentrations were found to vary from 1.54 to 5.37 Bq/kg. The exhalation rates were found to vary from 338.81 to 1426.47 Bq/m 2 d. The values of the radon exhalation rate are found to correspond with the uranium concentration values measured by the germanium detector in the corresponding soil samples

  14. Definition of tolerable soil erosion values

    Directory of Open Access Journals (Sweden)

    G. Sparovek

    1997-09-01

    Full Text Available Although the criteria for defining erosion tolerance are well established, the limits generally used are not consistent with natural, economical and technological conditions. Rates greater than soil formation can be accepted only until a minimum of soil depth is reached, provided that they are not associated with environmental hazard or productivity losses. A sequence of equations is presented to calculate erosion tolerance rates through time. The selection of equation parameters permits the definition of erosion tolerance rates in agreement with environmental, social and technical needs. The soil depth change that is related to irreversible soil degradation can be calculated. The definition of soil erosion tolerance according to these equations can be used as a guideline for sustainable land use planning and is compatible with expert systems.

  15. Impact of Soil Heavy Metal Pollution on Food Safety in China.

    Directory of Open Access Journals (Sweden)

    Xiuying Zhang

    Full Text Available Food safety is a major concern for the Chinese public. This study collected 465 published papers on heavy metal pollution rates (the ratio of the samples exceeding the Grade II limits for Chinese soils, the Soil Environmental Quality Standard-1995 in farmland soil throughout China. The results showed that Cd had the highest pollution rate of 7.75%, followed by Hg, Cu, Ni and Zn, Pb and Cr had the lowest pollution rates at lower than 1%. The total pollution rate in Chinese farmland soil was 10.18%, mainly from Cd, Hg, Cu, and Ni. The human activities of mining and smelting, industry, irrigation by sewage, urban development, and fertilizer application released certain amounts of heavy metals into soil, which resulted in the farmland soil being polluted. Considering the spatial variations of grain production, about 13.86% of grain production was affected due to the heavy metal pollution in farmland soil. These results many provide valuable information for agricultural soil management and protection in China.

  16. Aromatic plant production on metal contaminated soils

    International Nuclear Information System (INIS)

    Zheljazkov, Valtcho D.; Craker, Lyle E.; Xing Baoshan; Nielsen, Niels E.; Wilcox, Andrew

    2008-01-01

    Field and container experiments were conducted to assess the feasibility of growing aromatic crops in metal contaminated areas and the effect of metals on herbage and oil productivity. The field experiments were conducted in the vicinities of the Non-Ferrous Metals Combine (Zn-Cu smelter) near Plovdiv, Bulgaria using coriander, sage, dill, basil, hyssop, lemon balm, and chamomile grown at various distances from the smelter. Herbage essential oil yields of basil, chamomile, dill, and sage were reduced when they were grown closer to the smelter. Metal removal from the site with the harvestable plant parts was as high as 180 g ha -1 for Cd, 660 g ha -1 for Pb, 180 g ha -1 for Cu, 350 g ha -1 for Mn, and 205 g ha -1 for Zn. Sequential extraction of soil demonstrated that metal fractionation was affected by the distance to the smelter. With decreasing distance to the smelter, the transfer factor (TF) for Cu and Zn decreased but increased for Cd, while the bioavailability factor (BF) for Cd, Pb, Cu, Mn, and Zn decreased. Scanning electron microscopy and X-ray microanalyses of contaminated soil verified that most of the Pb, Cd, Mn, Cu, and Zn were in the form of small (< 1 μm) particles, although there were larger particles (1-5 μm) with high concentrations of individual metals. This study demonstrated that high concentrations of heavy metals in soil or growth medium did not result in metal transfer into the essential oil. Of the tested metals, only Cu at high concentrations may reduce oil content. Our results demonstrated that aromatic crops may not have significant phytoremediation potential, but growth of these crops in metal contaminated agricultural soils is a feasible alternative. Aromatic crops can provide economic return and metal-free final product, the essential oil

  17. Aromatic plant production on metal contaminated soils

    Energy Technology Data Exchange (ETDEWEB)

    Zheljazkov, Valtcho D. [Mississippi State, Department of Plant and Soil Sciences and North Mississippi Research and Extension Center, 5421 Highway 145 South, Verona, MS 38879 (United States)], E-mail: vj40@pss.msstate.edu; Craker, Lyle E.; Xing Baoshan [Department of Plant and Soil Sciences, 12 Stockbridge Hall, University of Massachusetts, Amherst, MA 01003 (United States); Nielsen, Niels E. [Plant Nutrition and Soil Fertility Lab, Department of Agricultural Sciences, Royal Veterinary and Agricultural University, Thorvaldsensvej 40, DK1871, Copenhagen (Denmark); Wilcox, Andrew [Harper Adams University College, Newport, Shropshire, TF10 8NB (United Kingdom)

    2008-06-01

    Field and container experiments were conducted to assess the feasibility of growing aromatic crops in metal contaminated areas and the effect of metals on herbage and oil productivity. The field experiments were conducted in the vicinities of the Non-Ferrous Metals Combine (Zn-Cu smelter) near Plovdiv, Bulgaria using coriander, sage, dill, basil, hyssop, lemon balm, and chamomile grown at various distances from the smelter. Herbage essential oil yields of basil, chamomile, dill, and sage were reduced when they were grown closer to the smelter. Metal removal from the site with the harvestable plant parts was as high as 180 g ha{sup -1} for Cd, 660 g ha{sup -1} for Pb, 180 g ha{sup -1} for Cu, 350 g ha{sup -1} for Mn, and 205 g ha{sup -1} for Zn. Sequential extraction of soil demonstrated that metal fractionation was affected by the distance to the smelter. With decreasing distance to the smelter, the transfer factor (TF) for Cu and Zn decreased but increased for Cd, while the bioavailability factor (BF) for Cd, Pb, Cu, Mn, and Zn decreased. Scanning electron microscopy and X-ray microanalyses of contaminated soil verified that most of the Pb, Cd, Mn, Cu, and Zn were in the form of small (< 1 {mu}m) particles, although there were larger particles (1-5 {mu}m) with high concentrations of individual metals. This study demonstrated that high concentrations of heavy metals in soil or growth medium did not result in metal transfer into the essential oil. Of the tested metals, only Cu at high concentrations may reduce oil content. Our results demonstrated that aromatic crops may not have significant phytoremediation potential, but growth of these crops in metal contaminated agricultural soils is a feasible alternative. Aromatic crops can provide economic return and metal-free final product, the essential oil.

  18. Radium and radon exhalation rate in soil samples of Hassan district of South Karnataka, India

    International Nuclear Information System (INIS)

    Jagadeesha, B.G.; Narayana, Y.

    2016-01-01

    The radon exhalation rate was measured in 32 soil samples collected from Hassan district of South Karnataka. Radon exhalation rate of soil samples was measured using can technique. The results show variation of radon exhalation rate with radium content of the soil samples. A strong correlation was observed between effective radium content and radon exhalation rate. In the present work, an attempt was made to assess the levels of radon in the environment of Hassan. Radon activities were found to vary from 2.25±0.55 to 270.85±19.16 Bq m"-"3 and effective radium contents vary from 12.06±2.98 to 1449.56±102.58 mBq kg"-"1. Surface exhalation rates of radon vary from 1.55±0.47 to 186.43±18.57 mBq m"-"2 h"-"1, and mass exhalation rates of radon vary from 0.312±0.07 to 37.46±2.65 mBq kg"-"1 h"-"1. (authors)

  19. Methane production potential and microbial community structure for different forest soils

    Science.gov (United States)

    Matsumoto, Y.; Ueyama, M.; Kominami, Y.; Endo, R.; Tokumoto, H.; Hirano, T.; Takagi, K.; Takahashi, Y.; Iwata, H.; Harazono, Y.

    2017-12-01

    Forest soils are often considered as a methane (CH4) sink, but anaerobic microsites potentially decrease the sink at the ecosystem scale. In this study, we measured biological CH4 production potential of soils at various ecosystems, including upland forests, a lowland forest, and a bog, and analyzed microbial community structure using 16S ribosomal RNA (rRNA) genes. Three different types of soil samples (upland, bank of the stream, and center of the stream) were collected from Yamashiro forest meteorology research site (YMS) at Kyoto, Japan, on 11 May 2017. The soils were incubated at dark and anaerobic conditions under three different temperatures (37°C, 25°C, and 10°C) from 9 June 2017. The upland soils emitted CH4 with largest yields among the three soils at 37°C and 25°C, although no CH4 emission was observed at 10°C. For all temperature ranges, the emission started to increase with a 14- to 20-days lag after the start of the incubation. The lag indicates a slow transition to anaerobic conditions; as dissolved oxygen in water decreased, the number and/or activity of anaerobic bacteria like methanogens increased. The soils at the bank and center of the stream emitted CH4 with smaller yields than the upland soils in the three temperature ranges. The microbial community analyses indicate that methanogenic archaea presented at the three soils including the aerobic upland soil, but compositions of methanogenic archaea were different among the soils. In upland soils, hydrogenotrophic methanogens, such as Methanobacterium and Methanothermobacter, consisted almost all of the total methanogen detected. In the bank and center of the stream, soils contained approximately 10-25% of acetoclastic methanogens, such as Methanosarcina and Methanosaeta, among the total methanogen detected. Methanotrophs, a genus of Methanobacteriaceae, was appeared in the all types of soils. We will present results from same incubation and 16S rRNA analyses for other ecosystems, including

  20. Integrated vacuum extraction/pneumatic soil fracturing system for remediation of low permeability soil

    International Nuclear Information System (INIS)

    Plaines, A.L.; Piniewski, R.J.; Yarbrough, G.D.

    1994-01-01

    There is wide use of vacuum extraction to remove volatile and semi-volatile organic compounds (VOCs) from unsaturated soil. At sites with soil of low permeability, VOC extraction rates may not be sufficient to meet soil clean-up objectives within the desired time frame. During vacuum extraction in low permeability soil, the diffusion rates of VOCs through the soil matrix may limit VOC removal rates. An increase in the number of subsurface paths for advective flow through the contaminated zone results in a larger mass of contaminant being removed in a shorter time frame, accelerating site remediation. One technique for increasing the number of subsurface flow paths is Terra Vac's process of pneumatic soil fracturing (PSF). In this process, pressurized air is injected into the subsurface, creating micro-fractures for the vacuum extraction system to withdraw contaminants. Similar to hydraulic fracturing techniques long used in the petroleum industry for increasing yield from oil and gas production wells, this technique has applications for soil remediation in low permeability conditions. Two case studies, one in Louisiana at a gasoline service station and one at a manufacturing plant in New York, are presented

  1. Changes in soil physical and chemical properties following organic matter removal and compaction: 20-year response of the aspen Lake-States Long Term Soil Productivity installations

    Science.gov (United States)

    Robert A. Slesak; Brian J. Palik; Anthony W. D' Amato; Valerie J. Kurth

    2017-01-01

    Soil functions that control plant resource availability can be altered by management activities such as increased organic matter (OM) removal and soil compaction during forest harvesting. The Long Term Soil Productivity study was established to evaluate how these practices influence soil and site productivity using experimental treatments that span a range of forest...

  2. Soil Fertility and Electrical Conductivity Affected by Organic Waste Rates and Nutrient Inputs

    Directory of Open Access Journals (Sweden)

    Davi Lopes do Carmo

    2016-01-01

    Full Text Available ABSTRACT The composition of organic waste (OW and its effect on soil processes may change soil fertility and electrical conductivity (EC. The side effects of waste use in crop fertilization are poorly understood for Brazilian soils. This study examined the effect of the addition of 15 different organic wastes to Oxisols and a Neosol on pH, base saturation, EC, cation exchange capacity (CEC at pH 7, and the availability of Al, macro (P, K, Ca2+, Mg2+ and S and micronutrients (B, Fe2+, Mn2+, Cu2+ and Zn2+. Soil samples (150 g were treated with chicken, pig, horse, cattle, and quail manures, sewage sludge 1 and 2, eucalyptus sawdust, plant substrate, coconut fiber, pine bark, coffee husk, peat, limed compost, and biochar. Wastes were added considering a fixed amount of C (2 g kg-1, which resulted in waste rates ranging from 2.5 to 25.6 Mg ha-1. The soil-waste mixtures were incubated for 330 days in laboratory conditions. The waste liming or acidification values were soil-dependent. The use of some manures and compost increased the pH to levels above of those considered adequate for plant growth. The soil EC was slightly increased in the Neosol and in the medium textured Oxisol, but it was sharply changed (from 195 to 394 µS cm-1 by the addition of organic wastes in the clayey Oxisol, although the EC values were below the range considered safe for plant growth. Changes in the soil availability of P, K+, Ca2+ and Zn2+ were highly related to the inputs of these nutrients by the wastes, and other factors in soil changed due to waste use. Organic waste use simultaneously affects different soil fertility attributes; thus, in addition to the target nutrient added to the soil, the soil acidity buffering capacity and the waste liming and agronomic value must be taken into account in the waste rate definition.

  3. Soil Degradation-Induced Decline in Productivity of Sub-Saharan African Soils: The Prospects of Looking Downwards the Lowlands with the Sawah Ecotechnology

    Directory of Open Access Journals (Sweden)

    Sunday E. Obalum

    2012-01-01

    Full Text Available The paper provides an insight into the problem of land degradation in Sub-Saharan Africa, with emphasis on soil erosion and its effect on soil quality and productivity, and proposes a lowland-based rice-production technology for coping with the situation. Crop yields are, in addition to the degree of past and current erosion, determined by a number of interacting variables. This, coupled with the generally weak database on erosion-induced losses in crop yield in spite of the region’s high vulnerability to erosion, makes it difficult to attain a reliable inference on the cause-effect relationship between soil loss and productivity. Available data suggest, however, that the region is at risk of not meeting up with the challenges of agriculture in this 21st century. Based on the few studies reviewed, methodology appears to have an overwhelming influence on the erosion-productivity response, whereas issues bordering on physical environment and soil affect the shape of the response curve. We argue that the sawah ecotechnology has the potential of countering the negative agronomic and environmental impacts of land degradation in Sub-Saharan Africa. This is a farmer-oriented, low-cost system of managing soil, water, and nutrient resources for enhancing lowland rice productivity and realizing Green Revolution in the region.

  4. The Influence of Ecological and Conventional Plant Production Systems on Soil Microbial Quality under Hops (Humulus lupulus)

    Science.gov (United States)

    Oszust, Karolina; Frąc, Magdalena; Gryta, Agata; Bilińska, Nina

    2014-01-01

    The knowledge about microorganisms—activity and diversity under hop production is still limited. We assumed that, different systems of hop production (within the same soil and climatic conditions) significantly influence on the composition of soil microbial populations and its functional activity (metabolic potential). Therefore, we compared a set of soil microbial properties in the field experiment of two hop production systems (a) ecological based on the use of probiotic preparations and organic fertilization (b) conventional—with the use of chemical pesticides and mineral fertilizers. Soil analyses included following microbial properties: The total number microorganisms, a bunch of soil enzyme activities, the catabolic potential was also assessed following Biolog EcoPlates®. Moreover, the abundance of ammonia-oxidizing archaea (AOA) was characterized by terminal restriction fragment length polymorphism analysis (T-RFLP) of PCR ammonia monooxygenase α-subunit (amoA) gene products. Conventional and ecological systems of hop production were able to affect soil microbial state in different seasonal manner. Favorable effect on soil microbial activity met under ecological, was more probably due to livestock-based manure and fermented plant extracts application. No negative influence on conventional hopyard soil was revealed. Both type of production fulfilled fertilizing demands. Under ecological production it was due to livestock-based manure fertilizers and fermented plant extracts application. PMID:24897025

  5. The Influence of Ecological and Conventional Plant Production Systems on Soil Microbial Quality under Hops (Humulus lupulus

    Directory of Open Access Journals (Sweden)

    Karolina Oszust

    2014-06-01

    Full Text Available The knowledge about microorganisms—activity and diversity under hop production is still limited. We assumed that, different systems of hop production (within the same soil and climatic conditions significantly influence on the composition of soil microbial populations and its functional activity (metabolic potential. Therefore, we compared a set of soil microbial properties in the field experiment of two hop production systems (a ecological based on the use of probiotic preparations and organic fertilization (b conventional—with the use of chemical pesticides and mineral fertilizers. Soil analyses included following microbial properties: The total number microorganisms, a bunch of soil enzyme activities, the catabolic potential was also assessed following Biolog EcoPlates®. Moreover, the abundance of ammonia-oxidizing archaea (AOA was characterized by terminal restriction fragment length polymorphism analysis (T-RFLP of PCR ammonia monooxygenase α-subunit (amoA gene products. Conventional and ecological systems of hop production were able to affect soil microbial state in different seasonal manner. Favorable effect on soil microbial activity met under ecological, was more probably due to livestock-based manure and fermented plant extracts application. No negative influence on conventional hopyard soil was revealed. Both type of production fulfilled fertilizing demands. Under ecological production it was due to livestock-based manure fertilizers and fermented plant extracts application.

  6. Biochar from different residues on soil properties and common bean production

    Directory of Open Access Journals (Sweden)

    Isley Cristiellem Bicalho da Silva

    Full Text Available ABSTRACT: The production of biochar from organic residues promises to be an interesting strategy for the management of organic waste. To assess the effect of biochar on soil properties and the production and nutrition of common bean (Phaseolus vulgaris L., three simultaneous experiments were conducted in a greenhouse with different biochar from organic residues (rice husk, sawdust, and sorghum silage used as filtration material for swine biofertilizer. In each experiment the treatments consisted of five different biochar concentrations (0, 25, 50, 75 and 100 L m−3, arranged in a completely randomized design, with four repetitions. In the experiments, the use of biochar increased soil pH, cation exchange capacity, nutrient availability in the soil, and nutrient accumulation in grains. The biochar concentrations corresponding to the maximum production of grain dry matter of bean plants were 100, 68, and 71 L m−3 for biochar from rice husk filter (BRHF, biochar from sawdust filter (BSF, and biochar from sorghum silage filter (BSSF, respectively.

  7. Assessing Bioenergy Harvest Risks: Geospatially Explicit Tools for Maintaining Soil Productivity in Western US Forests

    Directory of Open Access Journals (Sweden)

    Deborah Page-Dumroese

    2011-09-01

    Full Text Available Biomass harvesting for energy production and forest health can impact the soil resource by altering inherent chemical, physical and biological properties. These impacts raise concern about damaging sensitive forest soils, even with the prospect of maintaining vigorous forest growth through biomass harvesting operations. Current forest biomass harvesting research concurs that harvest impacts to the soil resource are region- and site-specific, although generalized knowledge from decades of research can be incorporated into management activities. Based upon the most current forest harvesting research, we compiled information on harvest activities that decrease, maintain or increase soil-site productivity. We then developed a soil chemical and physical property risk assessment within a geographic information system for a timber producing region within the Northern Rocky Mountain ecoregion. Digital soil and geology databases were used to construct geospatially explicit best management practices to maintain or enhance soil-site productivity. The proposed risk assessments could aid in identifying resilient soils for forest land managers considering biomass operations, policy makers contemplating expansion of biomass harvesting and investors deliberating where to locate bioenergy conversion facilities.

  8. Soil quality improvement for crop production in semi-arid West Africa

    OpenAIRE

    Ouédraogo, E.

    2004-01-01

    Soil quality maintenance and crop production improvement in semi-arid West Africa require appropriate cropping technologies, which are ecologically sound and economically viable. Thus, on-farm and on-station experiments have been carried out on the central plateau and in the south of Burkina Faso The results show that adoption of improved soil fertility technologies such as composting by farmers is determined by soil fertility status, access to the market and social reasons. Organic amendment...

  9. Anaerobic digestate from biogas production as a resource for improving soil fertility: effects on crop yield and soil properties

    Science.gov (United States)

    Pastorelli, Roberta; Lagomarsino, Alessandra; Vignozzi, Nadia; Valboa, Giuseppe; Papini, Rossella; Fabiani, Arturo; Simoncini, Stefania; Mocali, Stefano; Piccolo, Raimondo

    2013-04-01

    Soil fertility is fundamental in determining crops productivity in all farming systems. Production of biogas through anaerobic digestion of energy crops generates residues that can represent a valuable resource to sustain and improve soil fertility and to increase soil organic matter content. Residues from anaerobic digestion contain organic fractions and available nutrients, that can thus be returned to the cultivation soil as fertilizer and soil conditioner. However, some unknown aspects of digested residues utilization remain to explore: i) the nutrient supply and the real potential for mineral fertilization substitution, ii) the impact on the structure and functioning of soil microbial communities, iii) the direct and indirect effects on soil structure, organic matter and C mineralization. The aim of the present research was to gain a better understanding of these aspects, evaluating the effects of anaerobic digestate application on soil properties and maize yield. With the main focus of comparing mineral fertilization (250 Kg N ha-1) with digested residues addition (at the dose of 25 % and 50 % of mineral fertilizer), a triplicate sets of plots were designed in a field experiment on a silty-clay loam soil in the southern Po Valley (Italy). The amount of applied residues was calculated according to its N content in order to fertilizer each plots with the same amount of total nitrogen. Residues from digestion showed a N content of 0.4 % (60 % as N-NH4) and a C/N ratio of 3. Changes in soil quality after residues application were studied with a holistic approach, involving microbiological, physical and chemical aspects of soil fertility. In particular, we determined: the abundance and diversity of bacterial and fungal soil communities; the soil organic matter content, its distribution within soil aggregates and the C mineralization potential; cation exchange capacity; the main macro and micro nutrients; bulk density; aggregate stability. No significant

  10. Evaluation of SMOS soil moisture products over the CanEx-SM10 area

    Science.gov (United States)

    The Soil Moisture and Ocean Salinity (SMOS) Earth observation satellite was launched in November 2009 to provide global soil moisture and ocean salinity measurements based on L-Band passive microwave measurements. Since its launch, different versions of SMOS soil moisture products processors have be...

  11. Estimating steady-state evaporation rates from bare soils under conditions of high water table

    Science.gov (United States)

    Ripple, C.D.; Rubin, J.; Van Hylckama, T. E. A.

    1970-01-01

    A procedure that combines meteorological and soil equations of water transfer makes it possible to estimate approximately the steady-state evaporation from bare soils under conditions of high water table. Field data required include soil-water retention curves, water table depth and a record of air temperature, air humidity and wind velocity at one elevation. The procedure takes into account the relevant atmospheric factors and the soil's capability to conduct 'water in liquid and vapor forms. It neglects the effects of thermal transfer (except in the vapor case) and of salt accumulation. Homogeneous as well as layered soils can be treated. Results obtained with the method demonstrate how the soil evaporation rates·depend on potential evaporation, water table depth, vapor transfer and certain soil parameters.

  12. Acidification and Nitrogen Eutrophication of Austrian Forest Soils

    Directory of Open Access Journals (Sweden)

    Robert Jandl

    2012-01-01

    Full Text Available We evaluated the effect of acidic deposition and nitrogen on Austrian forests soils. Until thirty years ago air pollution had led to soil acidification, and concerns on the future productivity of forests were raised. Elevated rates of nitrogen deposition were believed to cause nitrate leaching and imbalanced forest nutrition. We used data from a soil monitoring network to evaluate the trends and current status of the pH and the C : N ratio of Austrian forest soils. Deposition measurements and nitrogen contents of Norway spruce needles and mosses were used to assess the nitrogen supply. The pH values of soils have increased because of decreasing proton depositions caused by reduction of emissions. The C : N ratio of Austrian forest soils is widening. Despite high nitrogen deposition rates the increase in forest stand density and productivity has increased the nitrogen demand. The Austrian Bioindicator Grid shows that forest ecosystems are still deficient in nitrogen. Soils retain nitrogen efficiently, and nitrate leaching into the groundwater is presently not a large-scale problem. The decline of soil acidity and the deposition of nitrogen together with climate change effects will further increase the productivity of the forests until a limiting factor such as water scarcity becomes effective.

  13. Shrubland primary production and soil respiration diverge along European climate gradient

    DEFF Research Database (Denmark)

    Reinsch, Sabine; Koller, Eva; Sowerby, Alwyn

    2017-01-01

    uncertain. Here we show the responses of ecosystem C to 8-12 years of experimental drought and night-time warming across an aridity gradient spanning seven European shrublands using indices of C assimilation (aboveground net primary production: aNPP) and soil C efflux (soil respiration: Rs). The changes...

  14. Hydro-geomechanical behaviour of gas-hydrate bearing soils during gas production through depressurization and CO2 injection

    Science.gov (United States)

    Deusner, C.; Gupta, S.; Kossel, E.; Bigalke, N.; Haeckel, M.

    2015-12-01

    Results from recent field trials suggest that natural gas could be produced from marine gas hydrate reservoirs at compatible yields and rates. It appears, from a current perspective, that gas production would essentially be based on depressurization and, when facing suitable conditions, be assisted by local thermal stimulation or gas hydrate conversion after injection of CO2-rich fluids. Both field trials, onshore in the Alaska permafrost and in the Nankai Trough offshore Japan, were accompanied by different technical issues, the most striking problems resulting from un-predicted geomechanical behaviour, sediment destabilization and catastrophic sand production. So far, there is a lack of experimental data which could help to understand relevant mechanisms and triggers for potential soil failure in gas hydrate production, to guide model development for simulation of soil behaviour in large-scale production, and to identify processes which drive or, further, mitigate sand production. We use high-pressure flow-through systems in combination with different online and in situ monitoring tools (e.g. Raman microscopy, MRI) to simulate relevant gas hydrate production scenarios. Key components for soil mechanical studies are triaxial systems with ERT (Electric resistivity tomography) and high-resolution local strain analysis. Sand production control and management is studied in a novel hollow-cylinder-type triaxial setup with a miniaturized borehole which allows fluid and particle transport at different fluid injection and flow conditions. Further, the development of a large-scale high-pressure flow-through triaxial test system equipped with μ-CT is ongoing. We will present results from high-pressure flow-through experiments on gas production through depressurization and injection of CO2-rich fluids. Experimental data are used to develop and parametrize numerical models which can simulate coupled process dynamics during gas-hydrate formation and gas production.

  15. Organochlorine Pesticides and Degradation Products in Soil around ...

    African Journals Online (AJOL)

    The levels and compositions of organochlorine pesticides and degradation products in soil samples collected from a former formulation plant in Morogoro municipality, Tanzania, were determined. Extraction was performed by pressurized fluid extraction using n-hexane:acetone (75:25) mixture. Clean-up of extracts was ...

  16. The influence of the sorptive properties of organic soils on the migration rate of 137Cs

    International Nuclear Information System (INIS)

    Chibowski, S.; Zygmunt, J.

    2002-01-01

    Using a compartment model, the migration rates of 137 Cs were calculated for two types of organic soils: a low peat-muck soil and a black earth. The migration rates of 137 Cs in the tested soils turned out to be significantly higher than in mineral types examined earlier and ranged from 0.6 to 12.3 cm/year. The partition coefficients (K d ) were also determined for samples with varying organic matter content (OM) that were taken from different layers of the studied soils. The experimental results indicate that there is a clear relationship between K d values and OM. The investigation was widened by microcalorimetric measurements which confirmed that the adsorption of 137 Cs on the organic soils is low

  17. Application of the 137Cs technique to quantify soil redistribution rates in paleohumults from Central-South Chile

    International Nuclear Information System (INIS)

    Schuller, P.; Sepulveda, A.; Trumper, R.E.; Castillo, A.

    2000-01-01

    The objective of the present study was to evaluate the applicability of the 137 Cs technique in obtaining spatial distributed information on mean soil redistribution rates in Central-South Chile. For this purpose four fields of Palehumult soil and contrasting land use and management were selected in the Coastal Mountain Range of the 9th Region: Crop fields under subsistence and commercial management and non-permanent prairies under subsistence and commercial management. The spatial distribution of the soil redistribution rates obtained by the 137 Cs method was similar to the one obtained by pedological observations. Also, annual sediment fluxes measured at experimental plots were similar to the erosion rates determined by the 137 Cs method at adjacent points. The 137 Cs technique is seen as an efficient method to obtain long-term soil redistribution rates under the climatic conditions and the soil type selected in Chile. In the future, it is necessary to study the applicability of the method under other climatic conditions and soil types occurring in Chile in which erosion is not so evident, and to adjust the method to optimise costs and benefits. (author) [es

  18. On the remote measurement of evaporation rates from bare wet soil under variable cloud cover

    Science.gov (United States)

    Auer, S.

    1976-01-01

    Evaporation rates from a natural wet soil surface are calculated from an energy balance equation at 0.1-hour intervals. A procedure is developed for calculating the heat flux through the soil surface from a harmonic analysis of the surface temperature curve. The evaporation integrated over an entire 24-hour period is compared with daily evaporation rates obtained from published models.

  19. Quantifying Soil Erosion and Deposition Rates in Tea Plantation Area, Cameron Highlands, Malaysia Using 137Cs

    International Nuclear Information System (INIS)

    Zaini Hamzah; Che Yasmin Amirudin; Ahmad Saat; Ahmad Saat; Ab Khalik Wood

    2014-01-01

    The soil erosion and deposition in the hilly area is a great concern for the planters. In this study, the tea plantation was chosen to quantify the rates of soil erosion and deposition for it will provide information on the improvement of soil conditions and cost reduction of fertilizer consumption. The aims of this research are to determine the rate of soil erosion and deposition using environmental radionuclide, 137 Cs. Soil profile samples were collected by using scrapper plate and two cores soil sample were collected in the undisturbed forests area nearby. The 137 Cs activity concentration was measured using low background coaxial hyper pure germanium detector gamma spectrometer based on 137 Cs gamma energy peak at 661.66 keV. The highest erosion rate using Proportional Models and Mass Balance Model 1 was found in point HE top area which is 52.39 t ha -1 yr -1 and 95.53 t ha -1 yr -1 respectively while the lowest at location HF top which is 4.78 t ha -1 yr -1 and 4.97 t ha -1 yr -1 . The deposition rate was higher in HF center which is 216.82 t ha -1 yr -1 and 97.51 t ha -1 yr -1 and the lowest at HE center which is 0.05 t ha -1 yr -1 for both models used. (author)

  20. Biochar has no effect on soil respiration across Chinese agricultural soils.

    Science.gov (United States)

    Liu, Xiaoyu; Zheng, Jufeng; Zhang, Dengxiao; Cheng, Kun; Zhou, Huimin; Zhang, Afeng; Li, Lianqing; Joseph, Stephen; Smith, Pete; Crowley, David; Kuzyakov, Yakov; Pan, Genxing

    2016-06-01

    Biochar addition to soil has been widely accepted as an option to enhance soil carbon sequestration by introducing recalcitrant organic matter. However, it remains unclear whether biochar will negate the net carbon accumulation by increasing carbon loss through CO2 efflux from soil (soil respiration). The objectives of this study were to address: 1) whether biochar addition increases soil respiration; and whether biochar application rate and biochar type (feedstock and pyrolyzing system) affect soil respiration. Two series of field experiments were carried out at 8 sites representing the main crop production areas in China. In experiment 1, a single type of wheat straw biochar was amended at rates of 0, 20 and 40 tha(-1) in four rice paddies and three dry croplands. In experiment 2, four types of biochar (varying in feedstock and pyrolyzing system) were amended at rates of 0 and 20 tha(-1) in a rice paddy under rice-wheat rotation. Results showed that biochar addition had no effect on CO2 efflux from soils consistently across sites, although it increased topsoil organic carbon stock by 38% on average. Meanwhile, CO2 efflux from soils amended with 40 t of biochar did not significantly higher than soils amended with 20 t of biochar. While the biochars used in Experiment 2 had different carbon pools and physico-chemical properties, they had no effect on soil CO2 efflux. The soil CO2 efflux following biochar addition could be hardly explained by the changes in soil physic-chemical properties and in soil microbial biomass. Thus, we argue that biochar will not negate the net carbon accumulation by increasing carbon loss through CO2 efflux in agricultural soils. Copyright © 2016. Published by Elsevier B.V.

  1. Moessbauer Spectroscopy in the Characterization of waste product used like fertilizer in soil. Some Applications

    International Nuclear Information System (INIS)

    Furet, N. R.; Orihuela, D. L.; Hernandez

    2007-01-01

    At the present time, the use of industrial solid wastes is an important task, because a great effort that have been carried out to preserve the environmental and to obtain the high technologies. In this work, a characterization of a industrial waste product, on base of the monohydrous iron sulphate (FeSO 4 .1H 2 O) with a 15% approximately of free sulphuric acid, used like improvement of soil was carried out by Mossabuer spectroscopy. This waste product was used in a series of the experiences in parcels (where peaches, (Prunus persica), strawberries are cultivated) in the zone of Cartaya (Huelva, Spain). The characterisation of soil from the parcel before application of this product was carried out in order to analyse and compare with the final results by using the methods of the Moessbauer spectroscopy. High contents of Fe, S, and Zn at the studied product are observed . This elements are very important for plants. The pH in soil and Fe, Mn, and Zn contents in soil and leaf were determined. The knowledge of the main chemical-structural properties of this product, used like improvement of soil, will permit the study of the influence to) on the soil properly, b) on the peach leaves and c) on the foodstuff fruit. (Author)

  2. Effect of irrigation with treated wastewater on soil chemical properties and infiltration rate.

    Science.gov (United States)

    Bedbabis, Saida; Ben Rouina, Béchir; Boukhris, Makki; Ferrara, Giuseppe

    2014-01-15

    In Tunisia, water scarcity is one of the major constraints for agricultural activities. The reuse of treated wastewater (TWW) in agriculture can be a sustainable solution to face water scarcity. The research was conducted for a period of four years in an olive orchard planted on a sandy soil and subjected to irrigation treatments: a) rain-fed conditions (RF), as control b) well water (WW) and c) treated wastewater (TWW). In WW and TWW treatments, an annual amount of 5000 m(3) ha(-1) of water was supplied to the orchard. Soil samples were collected at the beginning of the study and after four years for each treatment. The main soil properties such as electrical conductivity (EC), pH, soluble cations, chloride (Cl(-)), sodium adsorption ratio (SAR), organic matter (OM) as well as the infiltration rate were investigated. After four years, either a significant decrease of pH and infiltration rate or a significant increase of OM, SAR and EC were observed in the soil subjected to treated wastewater treatment. Copyright © 2013. Published by Elsevier Ltd.

  3. Dynamic soil properties in response to anthropogenic disturbance

    Science.gov (United States)

    Vanacker, Veerle; Ortega, Raúl

    2013-04-01

    Anthropogenic disturbance of natural vegetation can profoundly alter the physical, chemical and biological processes within soils. Rapid removal of topsoil during intense farming can result in an imbalance between soil production through chemical weathering and physical erosion, with direct implications on local biogeochemical cycling. However, the feedbacks between soil erosion, chemical weathering and biogeochemical cycling in response to anthropogenic forcing are not yet fully understood. Here, we study dynamic soil properties for a rapidly changing anthropogenic landscape, and focus on the coupling between physical erosion, soil production and soil chemical weathering. The archaeological site of Santa Maria de Melque (Toledo, Central Spain) was selected for its remarkably long occupation history dating back to the 7th century AD. As part of the agricultural complex, four retention reservoirs were built in the Early Middle Ages. The sedimentary archive was used to track the evolution in sedimentation rates and geochemical properties of the sediment. Catchment-wide soil erosion rates vary slightly between the various occupation phases (7th century-now), but are of the same magnitude as the cosmogenic nuclide-derived erosion rates. However, there exists large spatial variation in physical erosion rates that are coupled with chemical weathering intensities. The sedimentary records suggest that there are important changes in the spatial pattern of sediment source areas through time as a result of changing land use patterns

  4. The effect of wheat straw quality on the rate of its mineralisation in soil

    Directory of Open Access Journals (Sweden)

    Tatuśko Natalia

    2017-06-01

    Full Text Available The aim of this study was to assess the effect of straw of two spring wheat cultivars, Tybalt – with the culm filled with pith, and Ostka Smolicka – with the hollow culm, added to light textured soil, on the mineralisation rate of organic matter. The incubation experiment was established under laboratory conditions and comprised three experimental combinations: K1 was soil with an addition of pith-filled culms, K2 – soil with an addition of straw with hollow culms, and K0 – the control with no straw added. In all the combinations, mineral fertilisation was applied in the form of urea. Incubation lasted for 14 months. At specific dates the amounts of CO2 released within 24 h and pH values were recorded. The rate of organic matter mineralisation was expressed in mg CO2·d−1. Analyses showed that the addition of straw, both with pith-filled and hollow culms, significantly influenced the mineralisation of organic matter in the first months of incubation. Mineralisation was most intensive in the soil incubated with straw with hollow culms. The large amount of released carbon dioxide in the first days of incubation caused a decrease in pH both in the control soil and in soils with the addition of straw. The change in the soil reaction to its initial value was recorded at day 222 for the soil combination K0 and at day 250 of incubation in soils fertilised with straw.

  5. Composition of structural fragments and the mineralization rate of organic matter in zonal soils

    Science.gov (United States)

    Larionova, A. A.; Zolotareva, B. N.; Kolyagin, Yu. G.; Kvitkina, A. K.; Kaganov, V. V.; Kudeyarov, V. N.

    2015-10-01

    Comparative analysis of the climatic characteristics and the recalcitrance against decomposition of organic matter in the zonal soil series of European Russia, from peat surface-gley tundra soil to brown semidesert soil, has assessed the relationships between the period of biological activity, the content of chemically stable functional groups, and the mineralization of humus. The stability of organic matter has been determined from the ratio of functional groups using the solid-state 13C NMR spectroscopy of soil samples and the direct measurements of organic matter mineralization from CO2 emission. A statistically significant correlation has been found between the period of biological activity and the humification indices: the CHA/CFA ratio, the aromaticity, and the alkyl/ O-alkyl ratio in organic matter. The closest correlation has been observed between the period of biological activity and the alkyl/ O-alkyl ratio; therefore, this parameter can be an important indicator of the soil humus status. A poor correlation between the mineralization rate and the content of chemically stable functional groups in soil organic matter has been revealed for the studied soil series. At the same time, the lowest rate of carbon mineralization has been observed in southern chernozem characterized by the maximum content of aromatic groups (21% Corg) and surface-gley peat tundra soil, where an extremely high content of unsubstituted CH2 and CH3 alkyl groups (41% Corg) has been noted.

  6. Characterization and production and consumption processes of N2O emitted from temperate agricultural soils determined via isotopomer ratio analysis

    Science.gov (United States)

    Toyoda, Sakae; Yano, Midori; Nishimura, Sei-Ichi; Akiyama, Hiroko; Hayakawa, Atsushi; Koba, Keisuke; Sudo, Shigeto; Yagi, Kazuyuki; Makabe, Akiko; Tobari, Yoshifumi; Ogawa, Nanako O.; Ohkouchi, Naohiko; Yamada, Keita; Yoshida, Naohiro

    2011-06-01

    Isotopomer ratios of N2O (bulk nitrogen and oxygen isotope ratios, δ15Nbulk and δ18O, and intramolecular 15N site preference, SP) are useful parameters that characterize sources of this greenhouse gas and also provide insight into production and consumption mechanisms. We measured isotopomer ratios of N2O emitted from typical Japanese agricultural soils (Fluvisols and Andisols) planted with rice, wheat, soybean, and vegetables, and treated with synthetic (urea or ammonium) and organic (poultry manure) fertilizers. The results were analyzed using a previously reported isotopomeric N2O signature produced by nitrifying/denitrifying bacteria and a characteristic relationship between δ15Nbulk and SP during N2O reduction by denitrifying bacteria. Relative contributions from nitrification (hydroxylamine oxidation) and denitrification (nitrite reduction) to gross N2O production deduced from the analysis depended on soil type and fertilizer. The contribution from nitrification was relatively high (40%-70%) in Andisols amended with synthetic ammonium fertilizer, while denitrification was dominant (50%-90%) in the same soils amended with poultry manure during the period when N2O production occurred in the surface layer. This information on production processes is in accordance with that obtained from flux/concentration analysis of N2O and soil inorganic nitrogen. However, isotopomer analysis further revealed that partial reduction of N2O was pronounced in high-bulk density, alluvial soil (Fluvisol) compared to low-bulk density, volcanic ash soil (Andisol), and that the observed difference in N2O flux between normal and pelleted manure could have resulted from a similar mechanism with different rates of gross production and gross consumption. The isotopomeric analysis is based on data from pure culture bacteria and would be improved by further studies on in situ biological processes in soils including those by fungi. When flux/concentration-weighted average isotopomer

  7. Fire increases the risk of higher soil N2O emissions from Mediterranean Macchia ecosystems

    DEFF Research Database (Denmark)

    Karhu, Kristiina; Dannenmann, M.; Kitzler, B.

    2015-01-01

    on climate change. However, the potential importance of indirect GHG emissions due to changes in soil biological and chemical properties after fire is less well known. Increased soil mineral nitrogen (N) concentrations after fire pose a risk for increased emissions of gaseous N, but studies on the post......-fire N2O production and soil N turnover rates (mineralization, nitrification, microbial immobilization, denitrification) are still rare. We determined N2O production, rates of N turnover and pathways for N2O production from the soil of burned and unburned plots of a Macchia shrubland in central Spain...... using a 15N labelling approach. Measurements were initiated before the controlled burning and continued for up to half a year after fire. Fire markedly increased the risk of N2O emissions from soil through denitrification (N2O production rate was 3 to ≈30 times higher in burned soils compared to control...

  8. Automated system for generation of soil moisture products for agricultural drought assessment

    Science.gov (United States)

    Raja Shekhar, S. S.; Chandrasekar, K.; Sesha Sai, M. V. R.; Diwakar, P. G.; Dadhwal, V. K.

    2014-11-01

    Drought is a frequently occurring disaster affecting lives of millions of people across the world every year. Several parameters, indices and models are being used globally to forecast / early warning of drought and monitoring drought for its prevalence, persistence and severity. Since drought is a complex phenomenon, large number of parameter/index need to be evaluated to sufficiently address the problem. It is a challenge to generate input parameters from different sources like space based data, ground data and collateral data in short intervals of time, where there may be limitation in terms of processing power, availability of domain expertise, specialized models & tools. In this study, effort has been made to automate the derivation of one of the important parameter in the drought studies viz Soil Moisture. Soil water balance bucket model is in vogue to arrive at soil moisture products, which is widely popular for its sensitivity to soil conditions and rainfall parameters. This model has been encoded into "Fish-Bone" architecture using COM technologies and Open Source libraries for best possible automation to fulfill the needs for a standard procedure of preparing input parameters and processing routines. The main aim of the system is to provide operational environment for generation of soil moisture products by facilitating users to concentrate on further enhancements and implementation of these parameters in related areas of research, without re-discovering the established models. Emphasis of the architecture is mainly based on available open source libraries for GIS and Raster IO operations for different file formats to ensure that the products can be widely distributed without the burden of any commercial dependencies. Further the system is automated to the extent of user free operations if required with inbuilt chain processing for every day generation of products at specified intervals. Operational software has inbuilt capabilities to automatically

  9. Decomposition of Diethylstilboestrol in Soil

    DEFF Research Database (Denmark)

    Gregers-Hansen, Birte

    1964-01-01

    The rate of decomposition of DES-monoethyl-1-C14 in soil was followed by measurement of C14O2 released. From 1.6 to 16% of the added C14 was recovered as C14O2 during 3 months. After six months as much as 12 to 28 per cent was released as C14O2.Determination of C14 in the soil samples after the e...... not inhibit the CO2 production from the soil.Experiments with γ-sterilized soil indicated that enzymes present in the soil are able to attack DES.......The rate of decomposition of DES-monoethyl-1-C14 in soil was followed by measurement of C14O2 released. From 1.6 to 16% of the added C14 was recovered as C14O2 during 3 months. After six months as much as 12 to 28 per cent was released as C14O2.Determination of C14 in the soil samples after...

  10. Measurement of gamma-ray dose rate in soil and transfer of radionuclides from soil to vegetation

    International Nuclear Information System (INIS)

    Khan, K.; Akhter, P.; Khan, H.M.; Ismail, M.

    2012-01-01

    Analysis of natural radionuclides in soil, vegetation and vegetable samples collected from some Northern areas of Pakistan was carried out by gamma -ray spectrometry (HPGe detector). The activity concentrations in soil ranged from 24.7 to 78.5 Bqkg/sup -1/, 21.7 to 75.3 Bqkg/sup -1/ and 298.5 to 570.8 Bqkg/sup -1/ for /sup 226/Ra, /sup 232/Th, and /sup 40/K with the mean values of 42.1, 43.3 and 418.3 Bqkg/sup -1/, respectively. In the present analysis, /sup 40/K was the major radionuclide present in soil, vegetation, fruit and vegetable samples. The transfer factors of these radionuclides from soil to vegetation, fruit and vegetable were found in the order: /sup 40/K>/sup 232/Th>/sup 226/Ra. The mean value of outdoor and indoor absorbed dose rate (D) in air was 64.61 and 77.54 nGyh/sup -1/. The activity concentrations of radionuclides found in all samples were nominal. Therefore, they are not associated with any potential source of health hazard to the general public. (Orig./A.B.)

  11. Impact of bioenergy production on carbon storage and soil functions

    Science.gov (United States)

    Prays, Nadia; Franko, Uwe

    2016-04-01

    An important renewable energy source is methane produced in biogas plants (BGPs) that convert plant material and animal excrements to biogas and a residue (BGR). If the plant material stems from crops produced specifically for that purpose, a BGP have a 'footprint' that is defined by the area of arable land needed for the production of these energy crops and the area for distributing the BGRs. The BGR can be used to fertilize these lands (reducing the need for carbon and nitrogen fertilizers), and the crop land can be managed to serve as a carbon sink, capturing atmospheric CO2. We focus on the ecological impact of different BGPs in Central Germany, with a specific interest in the long-term effect of BGR-fertilization on carbon storage within the footprint of a BGP. We therefore studied nutrient fluxes using the CANDY (CArbon and Nitrogen Dynamics) model, which processes site-specific information on soils, crops, weather, and land management to compute stocks and fluxes of carbon and nitrogen for agricultural fields. We used CANDY to calculated matter fluxes within the footprints of BGPs of different sizes, and studied the effect of the substrate mix for the BGP on the carbon dynamics of the soil. This included the land requirement of the BGR recycling when used as a fertilizer: the footprint of a BGP required for the production of the energy crop generally differs from its footprint required to take up its BGR. We demonstrate how these findings can be used to find optimal cropping choices and land management for sustainable soil use, maintaining soil fertility and other soil functions. Furthermore, site specific potentials and limitations for agricultural biogas production can be identified and applied in land-use planning.

  12. A cross-site comparison of factors influencing soil nitrification rates in northeastern USA forested watersheds

    Science.gov (United States)

    Ross, D.S.; Wemple, B.C.; Jamison, A.E.; Fredriksen, G.; Shanley, J.B.; Lawrence, G.B.; Bailey, S.W.; Campbell, J.L.

    2009-01-01

    Elevated N deposition is continuing on many forested landscapes around the world and our understanding of ecosystem response is incomplete. Soil processes, especially nitrification, are critical. Many studies of soil N transformations have focused on identifying relationships within a single watershed but these results are often not transferable. We studied 10 small forested research watersheds in the northeastern USA to determine if there were common factors related to soil ammonification and nitrification. Vegetation varied between mixed northern hardwoods and mixed conifers. Watershed surface soils (Oa or A horizons) were sampled at grid or transect points and analyzed for a suite of chemical characteristics. At each sampling point, vegetation and topographic metrics (field and GIS-based) were also obtained. Results were examined by watershed averages (n = 10), seasonal/watershed averages (n = 28), and individual sampling points (n = 608). Using both linear and tree regression techniques, the proportion of conifer species was the single best predictor of nitrification rates, with lower rates at higher conifer dominance. Similar to other studies, the soil C/N ratio was also a good predictor and was well correlated with conifer dominance. Unlike other studies, the presence of Acer saccharum was not by itself a strong predictor, but was when combined with the presence of Betula alleghaniensis. Topographic metrics (slope, aspect, relative elevation, and the topographic index) were not related to N transformation rates across the watersheds. Although found to be significant in other studies, neither soil pH, Ca nor Al was related to nitrification. Results showed a strong relationship between dominant vegetation, soil C, and soil C/N. ?? 2008 Springer Science+Business Media, LLC.

  13. Characteristics of soil under variations in clay, water saturation, and water flow rates, and the implications upon soil remediation

    International Nuclear Information System (INIS)

    Aikman, M.; Mirotchnik, K.; Kantzas, A.

    1997-01-01

    A potential remediation method for hydrocarbon contaminated soils was discussed. The new method was based on the use of proven and economic petroleum reservoir engineering methods for soil remediation. The methods that were applied included water and gas displacement methods together with horizontal boreholes as the flow inlet and outlets. This system could be used in the case of spills that seep beneath a plant or other immovable infrastructure which requires in-situ treatment schemes to decontaminate the soil. A study was conducted to characterize native soils and water samples from industrial plants in central Alberta and Sarnia, Ontario and to determine the variables that impact upon the flow conditions of synthetic test materials. The methods used to characterize the soils included X-Ray computed tomographic analysis, grain size and density measurements, and X-Ray diffraction. Clay content, initial water saturation, and water and gas flow rate were the variables that impacted on the flow conditions

  14. Estimating soil turnover rate from tree uprooting during hurricanes in Puerto Rico

    Science.gov (United States)

    Lenart, M.T.; Falk, D.A.; Scatena, F.N.; Osterkamp, W.R.

    2010-01-01

    Soil turnover by tree uprooting in primary and secondary forests on the island of Puerto Rico was measured in 42 study plots in the months immediately after the passage of a Category 3 hurricane. Trunk basal area explained 61% of the variability of mound volume and 53% of the variability of mound area. The proportion of uprooted trees, the number of uprooted trees, or the proportion of uprooted basal area explained 84-85% of the variation in hurricane-created mound area. These same variables explain 79-85% of the variation in mound volume. The study indicates that the soil turnover period from tree uprooting by Puerto Rican hurricanes is between 1600 and 4800 years. These rates are faster than soil turnover by landslides and background treefall in the same area and provide a useful age constraint on soil profile development and soil carbon sequestration in these dynamic landscapes. ?? 2009 Elsevier B.V.

  15. Elevated atmospheric CO2 increases microbial growth rates and enzymes activity in soil

    Science.gov (United States)

    Blagodatskaya, Evgenia; Blagodatsky, Sergey; Dorodnikov, Maxim; Kuzyakov, Yakov

    2010-05-01

    Increasing the belowground translocation of assimilated carbon by plants grown under elevated CO2 can cause a shift in the structure and activity of the microbial community responsible for the turnover of organic matter in soil. We investigated the long-term effect of elevated CO2 in the atmosphere on microbial biomass and specific growth rates in root-free and rhizosphere soil. The experiments were conducted under two free air carbon dioxide enrichment (FACE) systems: in Hohenheim and Braunschweig, as well as in the intensively managed forest mesocosm of the Biosphere 2 Laboratory (B2L) in Oracle, AZ. Specific microbial growth rates (μ) were determined using the substrate-induced respiration response after glucose and/or yeast extract addition to the soil. We evaluated the effect of elevated CO2 on b-glucosidase, chitinase, phosphatase, and sulfatase to estimate the potential enzyme activity after soil amendment with glucose and nutrients. For B2L and both FACE systems, up to 58% higher μ were observed under elevated vs. ambient CO2, depending on site, plant species and N fertilization. The μ-values increased linearly with atmospheric CO2 concentration at all three sites. The effect of elevated CO2 on rhizosphere microorganisms was plant dependent and increased for: Brassica napus=Triticum aestivumyeast extract then for those growing on glucose, i.e. the effect of elevated CO2 was smoothed on rich vs. simple substrate. So, the r/K strategies ratio can be better revealed by studying growth on simple (glucose) than on rich substrate mixtures (yeast extract). After adding glucose, enzyme activities under elevated CO2 were 1.2-1.9-fold higher than under ambient CO2. This indicates the increased activity of microorganisms, which leads to accelerated C turnover in soil under elevated CO2. Our results clearly showed that the functional characteristics of the soil microbial community (i.e. specific growth rates and enzymes activity) rather than total microbial biomass

  16. Assessment of soil redistribution rates by (137)Cs and (210)Pbex in a typical Malagasy agricultural field.

    Science.gov (United States)

    Rabesiranana, N; Rasolonirina, M; Solonjara, A F; Ravoson, H N; Raoelina Andriambololona; Mabit, L

    2016-02-01

    Soil degradation processes affect more than one-third of the Malagasy territory and are considered as the major environmental threat impacting the natural resources of the island. This innovative study reports about a pioneer test and use of radio-isotopic techniques (i.e. Cs-137 and Pb-210ex) under Madagascar agroclimatic condition to evaluate soil erosion magnitude. This preliminary investigation has been conducted in a small agricultural field situated in the eastern central highland of Madagascar, 40 km East from Antananarivo. Both anthropogenic Cs-137 and geogenic Pb-210 soil tracers provided similar results highlighting soil erosion rates reaching locally 18 t ha(-1) yr(-1,) a level almost two times higher than the sustainable soil loss rate under Madagascar agroclimatic condition. The sediment delivery ratio established with both radiotracers was above 80% indicating that most of the mobilized sediment exits the field. Assessing soil erosion rate through fallout radionuclides in Madagascar is a first step towards an efficient land and water resource management policy to optimise the effectiveness of future agricultural soil conservation practices. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Digestate influence after biogas production on soil parameters

    Energy Technology Data Exchange (ETDEWEB)

    Igaz, D.; Horak, J.; Kondrlova, E.; Cimo, J. [Department of Biomereorology and Hydrology, Slovak University of Agriculture in Nitra, Nirra (Slovakia)

    2011-07-01

    Energy demands of society pun pressure on the use of alternative ways of getting the energy. From this point of view, the controlled anaerobic fermentation seems to be the perspective biotechnology: The final product of this process is an energy valuable raw - biogas and bio sludge. There was experimentally tested an influence of bio sludge on hydrophysical characteristics at the field condition of site Barca (Slovak Republic) with clav-loam soil. Based on the obtained results from three-year field experiment can be concluded that the application of the bio sludge on the soil does not contribute to the deterioration of soil hydrophysical properties. There was observed a positive effect on these properties, with observed increase of average value of capillary suction capacity, field capacity, porosity, non-capillary porosity and hydraulic conductivity. There was also observed decrease of average values of ρ{sub s} and ρ{sub d}. (author)

  18. Recycling stabilised/solidified drill cuttings for forage production in acidic soils.

    Science.gov (United States)

    Kogbara, Reginald B; Dumkhana, Bernard B; Ayotamuno, Josiah M; Okparanma, Reuben N

    2017-10-01

    Stabilisation/solidification (S/S), which involves fixation and immobilisation of contaminants using cementitious materials, is one method of treating drill cuttings before final fate. This work considers reuse of stabilised/solidified drill cuttings for forage production in acidic soils. It sought to improve the sustainability of S/S technique through supplementation with the phytoremediation potential of plants, eliminate the need for landfill disposal and reduce soil acidity for better plant growth. Drill cuttings with an initial total petroleum hydrocarbon (TPH) concentration of 17,125 mg kg -1 and low concentrations of metals were treated with 5%, 10%, and 20% cement dosages. The treated drill cuttings were reused in granular form for growing a forage, elephant grass (Pennisetum purpureum), after mixing with uncontaminated soil. The grasses were also grown in uncontaminated soil. The phytoremediation and growth potential of the plants was assessed over a 12-week period. A mix ratio of one part drill cuttings to three parts uncontaminated soil was required for active plant growth. The phytoremediation ability of elephant grass (alongside abiotic losses) reduced the TPH level (up to 8795 mg kg -1 ) in the soil-treated-drill cuttings mixtures below regulatory (1000 mg kg -1 ) levels. There were also decreased concentrations of metals. The grass showed better heights and leaf lengths in soil containing drill cuttings treated with 5% cement dosage than in uncontaminated soil. The results suggest that recycling S/S treated drill cuttings for forage production may be a potential end use of the treated waste. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Managing soil microbial communities in grain production systems through cropping practices

    Science.gov (United States)

    Gupta, Vadakattu

    2013-04-01

    Cropping practices can significantly influence the composition and activity of soil microbial communities with consequences to plant growth and production. Plant type can affect functional capacity of different groups of biota in the soil surrounding their roots, rhizosphere, influencing plant nutrition, beneficial symbioses, pests and diseases and overall plant health and crop production. The interaction between different players in the rhizosphere is due to the plethora of carbon and nutritional compounds, root-specific chemical signals and growth regulators that originate from the plant and are modulated by the physico-chemical properties of soils. A number of plant and environmental factors and management practices can influence the quantity and quality of rhizodeposition and in turn affect the composition of rhizosphere biota communities, microbe-fauna interactions and biological processes. Some of the examples of rhizosphere interactions that are currently considered important are: proliferation of plant and variety specific genera or groups of microbiota, induction of genes involved in symbiosis and virulence, promoter activity in biocontrol agents and genes correlated with root adhesion and border cell quality and quantity. The observation of variety-based differences in rhizodeposition and associated changes in rhizosphere microbial diversity and function suggests the possibility for the development of varieties with specific root-microbe interactions targeted for soil type and environment i.e. designer rhizospheres. Spatial location of microorganisms in the heterogeneous field soil matrix can have significant impacts on biological processes. Therefore, for rhizosphere research to be effective in variable seasonal climate and soil conditions, it must be evaluated in the field and within a farming systems context. With the current focus on security of food to feed the growing global populations through sustainable agricultural production systems there is a

  20. Effect of Pulp mill sludge on soil characteristics, microbial diversity and vegetal production of Lollium perene

    Energy Technology Data Exchange (ETDEWEB)

    Gallardo, F.; Cea, M.; Diez, M. C.

    2009-07-01

    The Chemical properties of the sludge (High organic matter content, pH, buffer capacity, nitrogen and phosphorous level, and low concentration of trace heavy metals and organic pollutants) suggest that this material may represent a valuable resource as soil amendment, improving soil characteristics, microbial diversity and vegetal production of mill sludge addition to volcanic soil (Andisol) on soil characteristics, microbial diversity and vegetal production of Lollium perenne, in field assays. (Author)

  1. Context dependency and saturating effects of loss of rare soil microbes on plant productivity

    Directory of Open Access Journals (Sweden)

    Gera eHol

    2015-06-01

    Full Text Available Land use intensification is associated with loss of biodiversity and altered ecosystem functioning. Until now most studies on the relationship between biodiversity and ecosystem functioning focused on random loss of species, while loss of rare species that usually are the first to disappear received less attention. Here we test if the effect of rare microbial species loss on plant productivity depends on the origin of the microbial soil community. Soils were sampled from three land use types at two farms. Microbial communities with increasing loss of rare species were created by inoculating sterilized soils with serially diluted soil suspensions. After 8 months of incubation, the effects of the different soil communities on abiotic soil properties, soil processes, microbial community composition and plant productivity was measured. Dilution treatments resulted in increasing species loss, which was in relation to abundance of bacteria in the original field soil, without affecting most of the other soil parameters and processes. Microbial species loss affected plant biomass positively, negatively or not at all, depending on soil origin, but not on land use history. Even within fields the effects of dilution on plant biomass varied between replicates, suggesting heterogeneity in microbial community composition. The effects of medium and severe species loss on plant biomass were similar, pointing towards a saturating effect of species loss. We conclude that changes in the composition of the soil microbial community, including rare species loss, can affect plant productivity, depending on the composition of the initial microbial community. Future work on the relation between function and species loss effects should address this variation by including multiple sampling origins.

  2. Context dependency and saturating effects of loss of rare soil microbes on plant productivity.

    Science.gov (United States)

    Hol, W H Gera; de Boer, Wietse; de Hollander, Mattias; Kuramae, Eiko E; Meisner, Annelein; van der Putten, Wim H

    2015-01-01

    Land use intensification is associated with loss of biodiversity and altered ecosystem functioning. Until now most studies on the relationship between biodiversity and ecosystem functioning focused on random loss of species, while loss of rare species that usually are the first to disappear received less attention. Here we test if the effect of rare microbial species loss on plant productivity depends on the origin of the microbial soil community. Soils were sampled from three land use types at two farms. Microbial communities with increasing loss of rare species were created by inoculating sterilized soils with serially diluted soil suspensions. After 8 months of incubation, the effects of the different soil communities on abiotic soil properties, soil processes, microbial community composition, and plant productivity was measured. Dilution treatments resulted in increasing species loss, which was in relation to abundance of bacteria in the original field soil, without affecting most of the other soil parameters and processes. Microbial species loss affected plant biomass positively, negatively or not at all, depending on soil origin, but not on land use history. Even within fields the effects of dilution on plant biomass varied between replicates, suggesting heterogeneity in microbial community composition. The effects of medium and severe species loss on plant biomass were similar, pointing toward a saturating effect of species loss. We conclude that changes in the composition of the soil microbial community, including rare species loss, can affect plant productivity, depending on the composition of the initial microbial community. Future work on the relation between function and species loss effects should address this variation by including multiple sampling origins.

  3. Soil carbon stocks and carbon sequestration rates in seminatural grassland in Aso region, Kumamoto, Southern Japan.

    Science.gov (United States)

    Toma, Yo; Clifton-Brown, John; Sugiyama, Shinji; Nakaboh, Makoto; Hatano, Ryusuke; Fernández, Fabián G; Ryan Stewart, J; Nishiwaki, Aya; Yamada, Toshihiko

    2013-06-01

    Global soil carbon (C) stocks account for approximately three times that found in the atmosphere. In the Aso mountain region of Southern Japan, seminatural grasslands have been maintained by annual harvests and/or burning for more than 1000 years. Quantification of soil C stocks and C sequestration rates in Aso mountain ecosystem is needed to make well-informed, land-use decisions to maximize C sinks while minimizing C emissions. Soil cores were collected from six sites within 200 km(2) (767-937 m asl.) from the surface down to the k-Ah layer established 7300 years ago by a volcanic eruption. The biological sources of the C stored in the Aso mountain ecosystem were investigated by combining C content at a number of sampling depths with age (using (14) C dating) and δ(13) C isotopic fractionation. Quantification of plant phytoliths at several depths was used to make basic reconstructions of past vegetation and was linked with C-sequestration rates. The mean total C stock of all six sites was 232 Mg C ha(-1) (28-417 Mg C ha(-1) ), which equates to a soil C sequestration rate of 32 kg C ha(-1)  yr(-1) over 7300 years. Mean soil C sequestration rates over 34, 50 and 100 years were estimated by an equation regressing soil C sequestration rate against soil C accumulation interval, which was modeled to be 618, 483 and 332 kg C ha(-1)  yr(-1) , respectively. Such data allows for a deeper understanding in how much C could be sequestered in Miscanthus grasslands at different time scales. In Aso, tribe Andropogoneae (especially Miscanthus and Schizoachyrium genera) and tribe Paniceae contributed between 64% and 100% of soil C based on δ(13) C abundance. We conclude that the seminatural, C4 -dominated grassland system serves as an important C sink, and worthy of future conservation. © 2013 Blackwell Publishing Ltd.

  4. Comparative studies of oil product regulation in polluted soil for several industrialized countries

    Science.gov (United States)

    Paccassoni, F.; Kalnina, D.; Piga, L.

    2017-10-01

    Oil contaminated sites are the consequence of a long period of industrialization. Oil is a complex mixture including aliphatic and aromatic hydrocarbons, which are known to have negative effects on human health and the environment. Dividing oil products in groups (fractions) of petroleum hydrocarbons that act alike in soil and water, one can better know what happens to them. Being able to understand the behaviour of oil products in soil, it will allow to implement prevention and remediation actions. Interventions on contaminated sites are bound to comply with regulatory limits that each country has set in their own environmental legislation. The different concentration thresholds of oil products in soil for several EU countries and Canada has led to compare: limit values, analytical method, soil characteristics and/or land use. This will allow to evaluate what could be the best regulation approach, assessing if it is better to consider soil matrix in the site or the specific land use or both of them. It will also assess what is the best analytical methodology to be adopted to achieve the pollutant concentrations in the soil in order to have comparable results among different countries, such as: Baltic countries (Latvia, Estonia, Lithuania), Nordic countries (Finland, Sweden, Norway, Denmark), Western countries (Italy and The Netherlands) and Canada, like gaschromatography in the range from C10 - C50. The study presents an overview of environmental regulatory system of several EU countries and Canada and the correlation between different parameters about oil products indicated in each environmental legislation.

  5. Phosphorus levels in soil and lettuce production due to phosphorus fertilization

    Directory of Open Access Journals (Sweden)

    José Ricardo Mantovani

    2014-09-01

    Full Text Available The leafy vegetables are considered nutrient-demanding, but are scarce in the literature works about phosphorus fertilization. This study aimed to evaluate the effect of phosphate on the production of lettuce, content and amount of P accumulated in leaf plants, and to relate levels of P in the clayey soil with plant production. The experiment was conducted in a greenhouse in pots in a randomized block design with ten treatments and four replications. The treatments were made up of P, corresponding to 0, 50, 100, 150, 200, 300, 400, 500, 600 and 700 mg dm-3, as triple superphosphate powder. Portions of 6 dm3 of the clay soil (420 g kg-1 clay received lime, aimed at raising the V % soil to 70 %, equivalent to 20 t ha-1 of cattle manure, and the phosphate fertilizer according to the treatments, remaining incubated for about 30 days. At the end of incubation, each pot received a change of lettuce cultivar Verônica. The plant harvesting was performed 39 days after transplanting the seedlings. O P gave large increases in growth and production of lettuce, and culture responded positively to the application of high doses of the nutrient. A dose of 350 mg dm-3, equivalent to 800 kg ha-1 P2O5, was the most suitable for growing lettuce in the clay soil. In this work conditions, the phosphorus fertilizations it was necessary when the P-Mehlich contents in the clay soil were less than 75 mg dm-3.

  6. Soil carbon sequestration in rainfed production systems in the semiarid tropics of India.

    Science.gov (United States)

    Srinivasarao, Ch; Lal, Rattan; Kundu, Sumanta; Babu, M B B Prasad; Venkateswarlu, B; Singh, Anil Kumar

    2014-07-15

    Severe soil organic carbon (SOC) depletion is a major constraint in rainfed agroecosystems in India because it directly influences soil quality, crop productivity and sustainability. The magnitude of soil organic, inorganic and total carbon stocks in the semi-arid bioclimate is estimated at 2.9, 1.9 and 4.8 Pg respectively. Sorghum, finger millet, pearl millet, maize, rice, groundnut, soybean, cotton, food legumes etc. are predominant crop production systems with a little, if any, recycling of organic matter. Data from the long term experiments on major rainfed production systems in India show that higher amount of crop residue C input (Mg/ha/y) return back to soil in soybean-safflower (3.37) system practiced in Vertisol region of central India. Long term addition of chemical fertilizer and organic amendments improved the SOC stock. For every Mg/ha increase in SOC stock in the root zone, there occurs an increase in grain yield (kg/ha) of 13, 101, 90, 170, 145, 18 and 160 for groundnut, finger millet, sorghum, pearl millet, soybean and rice, respectively. Long-term cropping without using any organic amendment and/or mineral fertilizers can severely deplete the SOC stock which is the highest in groundnut-finger millet system (0.92 Mg C/ha/y) in Alfisols. Some agroforestry systems also have a huge potential of C sequestration to the extent of 10Mg/ha/y in short rotation eucalyptus and Leucaena plantations. The critical level of C input requirements for maintaining SOC at the antecedent level ranges from 1.1 to 3.5 Mg C/ha/y and differs among soil type and production systems. National level policy interventions needed to promote sustainable use of soil and water resources include prohibiting residue burning, reducing deforestation, promoting integrated farming systems and facilitating payments for ecosystem services. A wide spread adoption of these measures can improve soil quality through increase in SOC sequestration and improvement in agronomic productivity of

  7. Lowering temperature to increase chemical oxidation efficiency: the effect of temperature on permanganate oxidation rates of five types of well defined organic matter, two natural soils, and three pure phase products.

    Science.gov (United States)

    de Weert, J P A; Keijzer, T J S; van Gaans, P F M

    2014-12-01

    In situ chemical oxidation (ISCO) is a soil remediation technique to remove organic pollutants from soil and groundwater with oxidants, like KMnO4. However, also natural organic compounds in soils are being oxidized, which makes the technique less efficient. Laboratory experiments were performed to investigate the influence of temperature on this efficiency, through its effect on the relative oxidation rates - by permanganate - of natural organic compounds and organic pollutants at 16 and 15°C. Specific types of organic matter used were cellulose, oak wood, anthracite, reed - and forest peat, in addition to two natural soils. Dense Non-Aqueous Phase Liquid-tetrachloroethene (DNAPL-PCE), DNAPL trichloroethene (DNAPL-TCE) and a mixture of DNAPL-PCE, -TCE and -hexachlorobutadiene were tested as pollutants. Compared to 16°C, oxidation was slower at 5°C for the specific types of organic matter and the natural soils, with exception of anthracite, which was unreactive. The oxidation rate of DNAPL TCE was lower at 5°C too. However, at this temperature oxidation was fast, implying that no competitive loss to natural organic compounds will be expected in field applications by lowering temperature. Oxidation of DNAPL-PCE and PCE in the mixture proceeded at equal rates at both temperatures, due to the dissolution rate as limiting factor. These results show that applying permanganate ISCO to DNAPL contamination at lower temperatures will limit the oxidation of natural organic matter, without substantially affecting the oxidation rate of the contaminant. This will make such remediation more effective and sustainable in view of protecting natural soil quality. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Assessment of soil redistribution rates by 137Cs and 210Pbex in a typical Malagasy agricultural field

    International Nuclear Information System (INIS)

    Rabesiranana, N.; Rasolonirina, M.; Solonjara, A.F.; Ravoson, H.N.; Raoelina Andriambololona; Mabit, L.

    2016-01-01

    Soil degradation processes affect more than one-third of the Malagasy territory and are considered as the major environmental threat impacting the natural resources of the island. This innovative study reports about a pioneer test and use of radio-isotopic techniques (i.e. Cs-137 and Pb-210ex) under Madagascar agroclimatic condition to evaluate soil erosion magnitude. This preliminary investigation has been conducted in a small agricultural field situated in the eastern central highland of Madagascar, 40 km East from Antananarivo. Both anthropogenic Cs-137 and geogenic Pb-210 soil tracers provided similar results highlighting soil erosion rates reaching locally 18 t ha −1  yr −1, a level almost two times higher than the sustainable soil loss rate under Madagascar agroclimatic condition. The sediment delivery ratio established with both radiotracers was above 80% indicating that most of the mobilized sediment exits the field. Assessing soil erosion rate through fallout radionuclides in Madagascar is a first step towards an efficient land and water resource management policy to optimise the effectiveness of future agricultural soil conservation practices. - Highlights: • A pioneer test of radioisotopic techniques under Madagascar agroclimatic condition for estimating soil erosion magnitude. • Cs-137 and Pb-210 ex Mass Balance Models (MBM) conjointly used to highlight timescale discrimination of erosion process. • Timescale discrimination suggests significant increase of erosion magnitude during the last 50 years. • Estimated erosion rates above 10 t ha −1 yr −1 indicate a clear threat for the sustainability of Malagasy soil resources. • Findings indicate the potential of using jointly Cs-137 and Pb-210 ex under local agroecological conditions.

  9. Engineering soil organic matter quality: Biodiesel Co-Product (BCP) stimulates exudation of nitrogenous microbial biopolymers

    Science.gov (United States)

    Redmile-Gordon, Marc A.; Evershed, Richard P.; Kuhl, Alison; Armenise, Elena; White, Rodger P.; Hirsch, Penny R.; Goulding, Keith W.T.; Brookes, Philip C.

    2015-01-01

    Biodiesel Co-Product (BCP) is a complex organic material formed during the transesterification of lipids. We investigated the effect of BCP on the extracellular microbial matrix or ‘extracellular polymeric substance’ (EPS) in soil which is suspected to be a highly influential fraction of soil organic matter (SOM). It was hypothesised that more N would be transferred to EPS in soil given BCP compared to soil given glycerol. An arable soil was amended with BCP produced from either 1) waste vegetable oils or 2) pure oilseed rape oil, and compared with soil amended with 99% pure glycerol; all were provided with 15N labelled KNO3. We compared transfer of microbially assimilated 15N into the extracellular amino acid pool, and measured concomitant production of exopolysaccharide. Following incubation, the 15N enrichment of total hydrolysable amino acids (THAAs) indicated that intracellular anabolic products had incorporated the labelled N primarily as glutamine and glutamate. A greater proportion of the amino acids in EPS were found to contain 15N than those in the THAA pool, indicating that the increase in EPS was comprised of bioproducts synthesised de novo. Moreover, BCP had increased the EPS production efficiency of the soil microbial community (μg EPS per unit ATP) up to approximately double that of glycerol, and caused transfer of 21% more 15N from soil solution into EPS-amino acids. Given the suspected value of EPS in agricultural soils, the use of BCP to stimulate exudation is an interesting tool to consider in the theme of delivering sustainable intensification. PMID:26635420

  10. Crop and soil specific N and P efficiency and productivity in Finland

    NARCIS (Netherlands)

    Bäckman, S.; Oude Lansink, A.G.J.M.

    2005-01-01

    This paper estimates a stochastic production frontier based on experimental data of cereals production in Finland over the period 1977-1994. The estimates of the production frontier are used to analyze nitrogen and phosphorous productivity and efficiency differences between soils and crops. For this

  11. Association of soil arsenic and nickel exposure with cancer mortality rates, a town-scale ecological study in Suzhou, China.

    Science.gov (United States)

    Chen, Kai; Liao, Qi Lin; Ma, Zong Wei; Jin, Yang; Hua, Ming; Bi, Jun; Huang, Lei

    2015-04-01

    Heavy metals and arsenic are well-known carcinogens. However, few studies have examined whether soil heavy metals and arsenic concentrations associate with cancer in the general population. In this ecological study, we aimed to evaluate the association of heavy metals and arsenic in soil with cancer mortality rates during 2005-2010 in Suzhou, China, after controlling for education and smoking prevalence. In 2005, a total of 1683 soil samples with a sampling density of one sample every 4 km(2) were analyzed. Generalized linear model with a quasi-Poisson regression was applied to evaluate the association between town-scale cancer mortality rates and soil heavy metal concentrations. Results showed that soil arsenic exposure had a significant relationship with colon, gastric, kidney, lung, and nasopharyngeal cancer mortality rates and soil nickel exposure was significantly associated with liver and lung cancer. The associations of soil arsenic and nickel exposure with colon, gastric, kidney, and liver cancer in male were higher than those in female. The observed associations of soil arsenic and nickel with cancer mortality rates were less sensitive to alternative exposure metrics. Our findings would contribute to the understanding of the carcinogenic effect of soil arsenic and nickel exposure in general population.

  12. Using (137)Cs measurements to estimate soil erosion rates in the Pčinja and South Morava River Basins, southeastern Serbia.

    Science.gov (United States)

    Petrović, Jelena; Dragović, Snežana; Dragović, Ranko; Đorđević, Milan; Đokić, Mrđan; Zlatković, Bojan; Walling, Desmond

    2016-07-01

    The need for reliable assessments of soil erosion rates in Serbia has directed attention to the potential for using (137)Cs measurements to derive estimates of soil redistribution rates. Since, to date, this approach has not been applied in southeastern Serbia, a reconnaissance study was undertaken to confirm its viability. The need to take account of the occurrence of substantial Chernobyl fallout was seen as a potential problem. Samples for (137)Cs measurement were collected from a zone of uncultivated soils in the watersheds of Pčinja and South Morava Rivers, an area with known high soil erosion rates. Two theoretical conversion models, the profile distribution (PD) model and diffusion and migration (D&M) model were used to derive estimates of soil erosion and deposition rates from the (137)Cs measurements. The estimates of soil redistribution rates derived by using the PD and D&M models were found to differ substantially and this difference was ascribed to the assumptions of the simpler PD model that cause it to overestimate rates of soil loss. The results provided by the D&M model were judged to more reliable. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Effect of Pesticide Application Rate on Yield of Vegetables and Soil ...

    African Journals Online (AJOL)

    komla

    In tomatoes, lower rates of lindane increased yields whereas the higher ... some countries because it has been found to cause seizures and damage to the nervous system, ... soil microbial activity, and (ii) to determine whether lindane has any ...

  14. The North-American Long-Term Soil Productivity Study: Concepts and literature

    Science.gov (United States)

    Deborah S. Page-Dumroese

    2010-01-01

    The resiliency of forest sites after a pulse disturbance is one of the key questions mandated by the National Forest Management Act (NFMA) of 1976. This Act mandated that we maintain the productive capacity of federally managed stands. The original USDA Forest Service soil quality standards were based largely on professional judgment. The North American Long-Term Soil...

  15. The ASCAT soil moisture product. A Review of its specifications, validation results, and emerging applications

    Energy Technology Data Exchange (ETDEWEB)

    Wagner, Wolfgang; Hahn, Sebastian; Kidd, Richard [Vienna Univ. of Technology (Austria). Dept. of Geodesy and Geoinformation] [and others

    2013-02-15

    Many physical, chemical and biological processes taking place at the land surface are strongly influenced by the amount of water stored within the upper soil layers. Therefore, many scientific disciplines require soil moisture observations for developing, evaluating and improving their models. One of these disciplines is meteorology where soil moisture is important due to its control on the exchange of heat and water between the soil and the lower atmosphere. Soil moisture observations may thus help to improve the forecasts of air temperature, air humidity and precipitation. However, until recently, soil moisture observations had only been available over a limited number of regional soil moisture networks. This has hampered scientific progress as regards the characterisation of land surface processes not just in meteorology but many other scientific disciplines as well. Fortunately, in recent years, satellite soil moisture data have increasingly become available. One of the freely available global soil moisture data sets is derived from the backscatter measurements acquired by the Advanced Scatterometer (ASCAT) that is a C-band active microwave remote sensing instrument flown on board of the Meteorological Operational (METOP) satellite series. ASCAT was designed to observe wind speed and direction over the oceans and was initially not foreseen for monitoring soil moisture over land. Yet, as argued in this review paper, the characteristics of the ASCAT instrument, most importantly its wavelength (5.7 cm), its high radiometric accuracy, and its multiple-viewing capabilities make it an attractive sensor for measuring soil moisture. Moreover, given the operational status of ASCAT, and its promising long-term prospects, many geoscientific applications might benefit from using ASCAT soil moisture data. Nonetheless, the ASCAT soil moisture product is relatively complex, requiring a good understanding of its properties before it can be successfully used in applications. To

  16. The ASCAT Soil Moisture Product: A Review of its Specifications, Validation Results, and Emerging Applications

    Directory of Open Access Journals (Sweden)

    Wolfgang Wagner

    2013-02-01

    Full Text Available Many physical, chemical and biological processes taking place at the land surface are strongly influenced by the amount of water stored within the upper soil layers. Therefore, many scientific disciplines require soil moisture observations for developing, evaluating and improving their models. One of these disciplines is meteorology where soil moisture is important due to its control on the exchange of heat and water between the soil and the lower atmosphere. Soil moisture observations may thus help to improve the forecasts of air temperature, air humidity and precipitation. However, until recently, soil moisture observations had only been available over a limited number of regional soil moisture networks. This has hampered scientific progress as regards the characterisation of land surface processes not just in meteorology but many other scientific disciplines as well. Fortunately, in recent years, satellite soil moisture data have increasingly become available. One of the freely available global soil moisture data sets is derived from the backscatter measurements acquired by the Advanced Scatterometer (ASCAT that is a C-band active microwave remote sensing instrument flown on board of the Meteorological Operational (METOP satellite series. ASCAT was designed to observe wind speed and direction over the oceans and was initially not foreseen for monitoring soil moisture over land. Yet, as argued in this review paper, the characteristics of the ASCAT instrument, most importantly its wavelength (5.7 cm, its high radiometric accuracy, and its multiple-viewing capabilities make it an attractive sensor for measuring soil moisture. Moreover, given the operational status of ASCAT, and its promising long-term prospects, many geoscientific applications might benefit from using ASCAT soil moisture data. Nonetheless, the ASCAT soil moisture product is relatively complex, requiring a good understanding of its properties before it can be successfully used in

  17. Impacts of paper sludge and manure on soil and biomass production of willow

    International Nuclear Information System (INIS)

    Quaye, Amos K.; Volk, Timothy A.; Hafner, Sasha; Leopold, Donald J.; Schirmer, Charles

    2011-01-01

    Land application of organic wastes to short rotation woody crops (SRWC) can reduce the environmental impacts associated with waste disposal and enhance the productivity of biomass production systems. Understanding the potential impacts of organic amendments however, requires the examination of changes in soil characteristics and plant productivity. This study was conducted to evaluate the effect of paper sludge and dairy manure on biomass production of shrub willow (Salix dasyclados SV1) and to determine the impacts of these amendments on soil chemical properties. Treatments included urea, dairy manure and paper sludge separately and in combination, and a control. These materials were applied in the summer of 2005 to two fields of SV1 at different stages of growth: An old field with one year old shoots on a 10 year old root system and a young field which was beginning regrowth after being coppiced at the end of its first growing season. Foliar nutrient concentrations and soil chemical properties were analyzed at the end of the second growing season after treatment application to determine plant response to the fertilization regimes and to determine the effects of fertilization on soil characteristics. Fertilization did not increase biomass production in either field. However, application of the N-poor paper sludge did not reduce yield either. In general, fertilization did not influence soil or foliar chemistry, although there were some exceptions. The lack of response observed in this study is probably related to the nutrient status of the site or losses of applied nutrients. -- Highlights: → The fertilization treatments did not have any significant effect biomass production. → Application of paper sludge did not reduce willow biomass yield in both fields. → Foliar N concentration of willow crops in this study is in the range considered for optimal growth. → The limited response of foliar nutrients to fertilization indicates that the site was not limited by

  18. Adapting the Caesium-137 technique to document soil redistribution rates associated with traditional cultivation practices in Haiti.

    Science.gov (United States)

    Velasco, H; Astorga, R Torres; Joseph, D; Antoine, J S; Mabit, L; Toloza, A; Dercon, G; Walling, Des E

    2018-03-01

    Large-scale deforestation, intensive land use and unfavourable rainfall conditions are responsible for significant continuous degradation of the Haitian uplands. To develop soil conservation strategies, simple and cost-effective methods are needed to assess rates of soil loss from farmland in Haiti. The fallout radionuclide caesium-137 ( 137 Cs) provides one such means of documenting medium-term soil redistribution rates. In this contribution, the authors report the first use in Haiti of 137 Cs measurements to document soil redistribution rates and the associated pattern of erosion/sedimentation rates along typical hillslopes within a traditional upland Haitian farming area. The local 137 Cs reference inventory, measured at an adjacent undisturbed flat area, was 670 Bq m -2 (SD = 100 Bq m -2 , CV = 15%, n = 7). Within the study area, where cultivation commenced in 1992 after deforestation, three representative downslope transects were sampled. These were characterized by 137 Cs inventories ranging from 190 to 2200 Bq m -2 . Although, the study area was cultivated by the local farmers, the 137 Cs depth distributions obtained from the area differed markedly from those expected from a cultivated area. They showed little evidence of tillage mixing within the upper part of the soil or, more particularly, of the near-uniform activities normally associated with the plough layer or cultivation horizon. They were very similar to that found at the reference site and were characterized by high 137 Cs activities at the surface and much lower activities at greater depths. This situation is thought to reflect the traditional manual tillage practices which cause limited disturbance and mixing of the upper part of the soil. It precluded the use of the conversion models normally used to estimate soil redistribution rates from 137 Cs measurements on cultivated soils and the Diffusion and Migration conversion model frequently used for uncultivated soils was modified for

  19. Soil moisture variability across different scales in an Indian watershed for satellite soil moisture product validation

    KAUST Repository

    Singh, Gurjeet

    2016-05-05

    Strategic ground-based sampling of soil moisture across multiple scales is necessary to validate remotely sensed quantities such as NASA’s Soil Moisture Active Passive (SMAP) product. In the present study, in-situ soil moisture data were collected at two nested scale extents (0.5 km and 3 km) to understand the trend of soil moisture variability across these scales. This ground-based soil moisture sampling was conducted in the 500 km2 Rana watershed situated in eastern India. The study area is characterized as sub-humid, sub-tropical climate with average annual rainfall of about 1456 mm. Three 3x3 km square grids were sampled intensively once a day at 49 locations each, at a spacing of 0.5 km. These intensive sampling locations were selected on the basis of different topography, soil properties and vegetation characteristics. In addition, measurements were also made at 9 locations around each intensive sampling grid at 3 km spacing to cover a 9x9 km square grid. Intensive fine scale soil moisture sampling as well as coarser scale samplings were made using both impedance probes and gravimetric analyses in the study watershed. The ground-based soil moisture samplings were conducted during the day, concurrent with the SMAP descending overpass. Analysis of soil moisture spatial variability in terms of areal mean soil moisture and the statistics of higher-order moments, i.e., the standard deviation, and the coefficient of variation are presented. Results showed that the standard deviation and coefficient of variation of measured soil moisture decreased with extent scale by increasing mean soil moisture. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  20. Soil respiration rate on the contrasting north- and south-facing slopes of a larch forest in central Siberia

    International Nuclear Information System (INIS)

    Yanagihara, Y.; Koike, T.; Matsuura, Y.; Mori, S.; Shibata, H.; Satoh, F.; Masuyagina, O.V.; Zyryanova, O.A.; Prokushkin, A.S.; Prokushkin, S.G.; Abaimov, A.P.

    2000-01-01

    In an attempt to evaluate global warming effects, we measured the soil respiration of the contrasting north- and south- facing slopes of a larch forest in central Siberia, located at Tura City in the Krasnoyarsk District, Russia. The north-facing slope is assumed to be the present condition while the south-facing slope may stand for the future warm condition. As a result of differences in solar radiation, there were clear differences between the north- and south- facing slopes in terms, for example, of the active layer as the growth rate of larch trees. The soil respiration rate was higher on the south-facing slope than on the north-facing slope. At the temperature of 15°C, soil respiration rate of the south-facing slope was ca. 6.2 μ mol CO 2 * m -2 s -1 , which was about 0.6 times lower than that of broad-leaved forests in Hokkaido. There was an exponential correlation between soil temperature at 10 cm depth and the efflux of CO 2 from the soil surface. Various conditions (soil temperature,. nitrogen content and soil water content) seemed to be more favorable for soil respiration on the south-facing slope. (author)

  1. Biomass distribution efficiency of rose cv. Charlotte grown in soil and substrates at second production peak

    Directory of Open Access Journals (Sweden)

    María Y González G

    2013-12-01

    Full Text Available Growing plants in substrates is an alternative for the production of roses under unfavorable soil conditions. The objective of this study was to determine the biomass distribution efficiency of rose cv. Charlotte grown in soil and substrates under greenhouse conditions until second production peak. In this trial, soil and substrates with 100% burned rice husk (100BR H; 65% burned rice husk: 35% coconut fiber (65BR H; 35% burned rice husk: 65% coconut fiber (35BR H; and 100% coconut fiber (100CF were used. The experimental design consisted of a randomized complete block design with three repetitions. Destructive sampling was carried out using whole plants and flowering stems at previously determined bud stages. Leaf area and dry matter in organs were measured and growth rate and physiological indexes were calculated. The assessed variables were fitted to logistic and exponential models. The plants grown in substrates with BR H (burned rice husk showed similar values regarding dry matter and fresh weight accumulation in organs. Plants in the soil treatment were the last ones to reach the different development stages of the flowering buds, while those that were grown in 100CF were the first ones. The treatments 35BR H and 100CF showed less growth of flowering stems, which was expressed in terms of relative dry matter increase per day. The plants grown in soil showed more dry matter in leaves and stems but less in flower buds. The 65BR H treatment showed some of the highest dry matter accumulations in leaves, stems and flower buds and also showed the highest leaf area ratio, leaf weight ratio, and specific leaf area values

  2. HONO (nitrous acid) emissions from acidic northern soils

    Science.gov (United States)

    Maljanen, Marja; Yli-Pirilä, Pasi; Joutsensaari, Jorma; Martikainen, Pertti J.

    2015-04-01

    The photolysis of HONO (nitrous acid) is an important source of OH radical, the key oxidizing agent in the atmosphere, contributing also to removal of atmospheric methane (CH4), the second most important greenhouse gas after carbon dioxide (CO2). The emissions of HONO from soils have been recently reported in few studies. Soil HONO emissions are regarded as missing sources of HONO when considering the chemical reactions in the atmosphere. The soil-derived HONO has been connected to soil nitrite (NO2-) and also directly to the activity of ammonia oxidizing bacteria, which has been studied with one pure culture. Our hypothesis was that boreal acidic soils with high nitrification activity could be also sources of HONO and the emissions of HONO are connected with nitrification. We selected a range of dominant northern acidic soils and showed in microcosm experiments that soils which have the highest nitrous oxide (N2O) and nitric oxide (NO) emissions (drained peatlands) also have the highest HONO production rates. The emissions of HONO are thus linked to nitrogen cycle and also NO and N2O emissions. Natural peatlands and boreal coniferous forests on mineral soils had the lowest HONO emissions. It is known that in natural peatlands with high water table and in boreal coniferous forest soils, low nitrification activity (microbial production of nitrite and nitrate) limits their N2O production. Low availability of nitrite in these soils is the likely reason also for their low HONO production rates. We also studied the origin of HONO in one peat soil with acetylene and other nitrification inhibitors and we found that HONO production is not closely connected to ammonium oxidation (nitrification). Acetylene blocked NO emissions but did not affect HONO or N2O emissions, thus there is another source behind HONO emission from these soils than ammonium oxidation. It is still an open question if this process is microbial or chemical origin.

  3. Soil aptitude for the production of sugarcane. Part I. Calibration in experimental and production conditions

    Directory of Open Access Journals (Sweden)

    Nelson C. Arzola Pina

    2015-02-01

    Full Text Available A database was created using the yield values and the soil characteristics from more than 50 field experiments, and from other areas that belonged to good producers in Cienfuegos. All the experiments were done on brown carbonated, brown non-carbonated and red ferralitic soils. The soils characteristics were selected based on a varied analysis of main components and taking the easily-determined variables. For each soil characteristic that was selected, a classification system was established, that encompasses several variable ranges, the category assigned to each range, and a point value for each category. This classification system was based on articles reviews, and also taking into account the results of many researchers. A linear regression analysis was done using sugarcane yield and the values of soils where the sugar cane was planted and the cases of “excellent management” and “adequate management” of the cultivar was discriminated. It was proved that the soil value and the sugarcane yield were highly related (linear regression, which made possible the elaboration of a table that relates the sugarcane productive potential according to the characteristics of the soil expressed by the accumulated points, depending on the quality of the cultivar management and the agricultural cycle (plant cane or ratoon.

  4. Early history of soil contamination with fission products

    International Nuclear Information System (INIS)

    Nagel, E.

    1985-01-01

    Underneath a balloon and instrument hut demolished today and on the natural pasture next to it, a series of 2 to 4-layer soil samples was carried out to determine the contents in Cs-137 and Sr-90. The results showed a sudded decrease of the Cs concentration behind the walls of the hut, but no further decrease towards the centre of the hut. As expected, the decrease of Sr-90 concentration was slower, both in a horizontal line and in the depth. The results reveal that the soil underneath the hut has not received further fission products since it was built in 1956 from depositions of later nuclear weapon tests. Furthermore, the radionuclides were not transported much further into lower strata so that by taking into consideration of the half-life of the two nuclides their concentration in the soil can be traced back to the year 1956 for comparison with the results measured at the time. (orig./HP) [de

  5. Soil and water pollution in a banana production region in tropical Mexico

    NARCIS (Netherlands)

    Geissen, V.; Que Ramos, F.; Bastidas-Bastidas, de P.J.; Díaz-González, G.; Bello-Mendoza, R.; Huerta-Lwanga, E.; Ruiz-Suárez, L.E.

    2010-01-01

    The effects of abundant Mancozeb (Mn, Zn— bisdithiocarbamate) applications (2.5 kg ha-1week-1 for 10 years) on soil and surface-, subsurface- and groundwater pollution were monitored in a banana production region of tropical Mexico. In soils, severe manganese accumulation was observed, wheras the

  6. An Intercomparison of Vegetation Products from Satellite-based Observations used for Soil Moisture Retrievals

    Science.gov (United States)

    Vreugdenhil, Mariette; de Jeu, Richard; Wagner, Wolfgang; Dorigo, Wouter; Hahn, Sebastian; Bloeschl, Guenter

    2013-04-01

    Vegetation and its water content affect active and passive microwave soil moisture retrievals and need to be taken into account in such retrieval methodologies. This study compares the vegetation parameterisation that is used in the TU-Wien soil moisture retrieval algorithm to other vegetation products, such as the Vegetation Optical Depth (VOD), Net Primary Production (NPP) and Leaf Area Index (LAI). When only considering the retrieval algorithm for active microwaves, which was developed by the TU-Wien, the effect of vegetation on the backscattering coefficient is described by the so-called slope [1]. The slope is the first derivative of the backscattering coefficient in relation to the incidence angle. Soil surface backscatter normally decreases quite rapidly with the incidence angle over bare or sparsely vegetated soils, whereas the contribution of dense vegetation is fairly uniform over a large range of incidence angles. Consequently, the slope becomes less steep with increasing vegetation. Because the slope is a derivate of noisy backscatter measurements, it is characterised by an even higher level of noise. Therefore, it is averaged over several years assuming that the state of the vegetation doesn't change inter-annually. The slope is compared to three dynamic vegetation products over Australia, the VOD, NPP and LAI. The VOD was retrieved from AMSR-E passive microwave data using the VUA-NASA retrieval algorithm and provides information on vegetation with a global coverage of approximately every two days [2]. LAI is defined as half the developed area of photosynthetically active elements of the vegetation per unit horizontal ground area. In this study LAI is used from the Geoland2 products derived from SPOT Vegetation*. The NPP is the net rate at which plants build up carbon through photosynthesis and is a model-based estimate from the BiosEquil model [3, 4]. Results show that VOD and slope correspond reasonably well over vegetated areas, whereas in arid

  7. Effective dose rate coefficients for exposure to contaminated soil

    Energy Technology Data Exchange (ETDEWEB)

    Veinot, K.G. [Easterly Scientific, Knoxville, TN (United States); Y-12 National Security Complex, Oak Ridge, TN (United States); Eckerman, K.F.; Easterly, C.E. [Easterly Scientific, Knoxville, TN (United States); Bellamy, M.B.; Hiller, M.M.; Dewji, S.A. [Oak Ridge National Laboratory, Center for Radiation Protection Knowledge, Oak Ridge, TN (United States); Hertel, N.E. [Oak Ridge National Laboratory, Center for Radiation Protection Knowledge, Oak Ridge, TN (United States); Georgia Institute of Technology, Atlanta, GA (United States); Manger, R. [University of California San Diego, Department of Radiation Medicine and Applied Sciences, La Jolla, CA (United States)

    2017-08-15

    The Oak Ridge National Laboratory Center for Radiation Protection Knowledge has undertaken calculations related to various environmental exposure scenarios. A previous paper reported the results for submersion in radioactive air and immersion in water using age-specific mathematical phantoms. This paper presents age-specific effective dose rate coefficients derived using stylized mathematical phantoms for exposure to contaminated soils. Dose rate coefficients for photon, electron, and positrons of discrete energies were calculated and folded with emissions of 1252 radionuclides addressed in ICRP Publication 107 to determine equivalent and effective dose rate coefficients. The MCNP6 radiation transport code was used for organ dose rate calculations for photons and the contribution of electrons to skin dose rate was derived using point-kernels. Bremsstrahlung and annihilation photons of positron emission were evaluated as discrete photons. The coefficients calculated in this work compare favorably to those reported in the US Federal Guidance Report 12 as well as by other authors who employed voxel phantoms for similar exposure scenarios. (orig.)

  8. Bioremediation of petroleum contaminated soil

    International Nuclear Information System (INIS)

    Autry, A.R.; Ellis, G.M.

    1992-01-01

    This paper reports on bioremediation, which offers a cost-competitive, effective remediation alternative for soil contaminated with petroleum products. These technologies involve using microorganisms to biologically degrade organic constituents in contaminated soil. All bioremediation applications must mitigate various environmental rate limiting factors so that the biodegradation rates for petroleum hydrocarbons are optimized in field-relevant situations. Traditional bioremediation applications include landfarming, bioreactors, and composting. A more recent bioremediation application that has proven successful involves excavation of contaminated soil. The process involves the placement of the soils into a powerscreen, where it is screened to remove rocks and larger debris. The screened soil is then conveyed to a ribbon blender, where it is mixed in batch with nutrient solution containing nitrogen, phosphorus, water, and surfactants. Each mixed soil batch is then placed in a curing pile, where it remains undisturbed for the remainder of the treatment process, during which time biodegradation by naturally occurring microorganisms, utilizing biochemical pathways mediated by enzymes, will occur

  9. Soil Hydrological Attributes of an Integrated Crop-Livestock Agroecosystem: Increased Adaptation through Resistance to Soil Change

    International Nuclear Information System (INIS)

    Liebig, M.A; Tanaka, D.L; Kronberg, S.L; Karn, J.F; Scholljegerdes, E.J

    2011-01-01

    Integrated crop-livestock systems have been purported to have significant agronomic and environmental benefits compared to specialized, single-enterprise production systems. However, concerns exist regarding the effect of livestock in integrated systems to cause soil compaction, thereby decreasing infiltration of water into soil. Such concerns are compounded by projections of more frequent high-intensity rainfall events from anticipated climate change, which would act to increase surface runoff and soil erosion. A study was conducted to evaluate the effects of residue management, frequency of hoof traffic, season, and production system (e.g., integrated annual cropping versus perennial grass) on infiltration rates from 2001 through 2008 in central North Dakota, USA. Imposed treatments had no effect on infiltration rate at three, six, and nine years after study establishment, implying that agricultural producers should not be concerned with inhibited infiltration in integrated annual cropping systems, where winter grazing is used. The use of no-till management, coupled with annual freeze/thaw and wet/dry cycles, likely conferred an inherent resistance to change in near-surface soil properties affecting soil hydrological attributes. Accordingly, caution should be exercised in applying these results to other regions or management systems.

  10. Effects of plant cover on soil N mineralization during the growing season in a sandy soil

    Science.gov (United States)

    Yao, Y.; Shao, M.; Wei, X.; Fu, X.

    2017-12-01

    Soil nitrogen (N) mineralization and its availability plays a vital role in regulating ecosystem productivity and C cycling, particularly in semiarid and desertified ecosystems. To determine the effect of plant cover on N turnover in a sandy soil ecosystem, we measured soil N mineralization and inorganic N pools in soil solution during growing season in a sandy soil covered with various plant species (Artemisia desertorum, Salix psammophila, and Caragana korshinskii). A bare sandy soil without any plant was selected as control. Inorganic N pools and N mineralization rates decreased overtime during the growing season, and were not affected by soil depth in bare land soils, but were significantly higher at the 0-10 cm layer than those at the 10-20 cm soil layer under any plant species. Soil inorganic N pool was dominated by ammonium, and N mineralization was dominated by nitrification regardless of soil depth and plant cover. Soils under C. korshinskii have significant higher inorganic N pools and N mineralization rate than soils under bare land and A. desertorum and S. psammophila, and the effects of plant cover were greater at the 0-10 cm soil layer than at the 10-20 cm layer. The effects of C. korshinskii on soil inorganic N pools and mineralization rate varied with the stage of growing season, with greater effects on N pools in the middle growing season, and greater effects on mineralization rate at the last half of the growing season. The results from this study indicate that introduction of C. korshinskii has the potential to increase soil N turnover and availability in sandy soils, and thus to decrease N limitation. Caragana korshinskii is therefore recommend for the remediation of the desertified land.

  11. Bioavailability of contaminants estimated from uptake rates into soil invertebrates

    International Nuclear Information System (INIS)

    Straalen, N.M. van; Donker, M.H.; Vijver, M.G.; Gestel, C.A.M. van

    2005-01-01

    It is often argued that the concentration of a pollutant inside an organism is a good indicator of its bioavailability, however, we show that the rate of uptake, not the concentration itself, is the superior predictor. In a study on zinc accumulation and toxicity to isopods (Porcellio scaber) the dietary EC 50 for the effect on body growth was rather constant and reproducible, while the internal EC 50 varied depending on the accumulation history of the animals. From the data a critical value for zinc accumulation in P. scaber was estimated as 53 μg/g/wk. We review toxicokinetic models applicable to time-series measurements of concentrations in invertebrates. The initial slope of the uptake curve is proposed as an indicator of bioavailability. To apply the dynamic concept of bioavailability in risk assessment, a set of representative organisms should be chosen and standardized protocols developed for exposure assays by which suspect soils can be evaluated. - Sublethal toxicity of zinc to isopods suggests that bioavailability of soil contaminants is best measured by uptake rates, not by body burdens

  12. Development of methods for remediation of artificial polluted soils and improvement of soils for ecologically clean agricultural production systems

    International Nuclear Information System (INIS)

    Bogachev, V.; Adrianova, G.; Zaitzev, V.; Kalinin, V.; Kovalenko, E.; Makeev, A.; Malikova, L.; Popov, Yu.; Savenkov, A.; Shnyakina, V.

    1996-01-01

    The purpose of the research: Development of methods for the remediation of artificial polluted soils and the improvement of polluted lands to ecologically clean agricultural production.The following tasks will be implemented in this project to achieve viable practical solutions: - To determine the priority pollutants, their ecological pathways, and sources of origin. - To form a supervised environmental monitoring data bank throughout the various geo system conditions. - To evaluate the degree of the bio geo system pollution and the influence on the health of the local human populations. - To establish agricultural plant tolerance levels to the priority pollutants. - To calculate the standard concentrations of the priority pollutants for main agricultural plant groups. - To develop a soil remediation methodology incorporating the structural, functional geo system features. - To establish a territory zone division methodology in consideration of the degree of component pollution, plant tolerance to pollutants, plant production conditions, and human health. - Scientific grounding of the soil remediation proposals and agricultural plant material introductions with soil pollution levels and relative plant tolerances to pollutants. Technological Means, Methods, and Approaches Final proposed solutions will be based upon geo system and ecosystem approaches and methodologies. The complex ecological valuation methods of the polluted territories will be used in this investigation. Also, laboratory culture in vitro, application work, and multi-factor field experiments will be conducted. The results will be statistically analyzed using appropriate methods. Expected Results Complex biogeochemical artificial province assessment according to primary pollutant concentrations. Development of agricultural plant tolerance levels relative to the priority pollutants. Assessment of newly introduced plant materials that may possess variable levels of pollution tolerance. Remediation

  13. Effects of nitrogen deposition and cattle grazing on productivity, invasion impact, and soil microbial processes in a serpentine grassland

    Science.gov (United States)

    Pasari, J.; Hernandez, D.; Selmants, P. C.; Keck, D.

    2010-12-01

    In recent decades, human activities have vastly increased the amount of biologically available nitrogen (N) in the biosphere. The resulting increase in N availability has broadly affected ecosystems through increased productivity, changes in species composition, altered nutrient cycles, and increases in invasion by exotic plant species, especially in systems that were historically low in N. California serpentine grasslands are N-limited ecosystems historically dominated by native species including several threatened and endangered plants and animals. Cattle grazing has emerged as the primary tool for controlling the impact of nitrophilic exotic grasses whose increased abundance has paralleled the regional traffic-derived increase in atmospheric N deposition. We examined the interactive effects of cattle grazing and N deposition on plant community composition, productivity, invasion resistance, and microbial processes in the Bay Area's largest serpentine grassland to determine the efficacy of current management strategies as well as the biogeochemical consequences of exotic species invasion. In the first two years of the study, aboveground net primary productivity decreased in response to grazing and increased in response to nitrogen addition. However, contrary to our hypotheses the change in productivity was not due to an increase in exotic species cover as there was little overall effect of grazing or N addition on species composition. Microbial activity was more responsive to grazing and N. Potential net N mineralization rates increased with N addition, but were not affected by grazing. In contrast, soil respiration rates were inhibited by grazing, but were not affected by N addition; suggesting strong carbon-limitation of soil microbial activity, particularly under grazing. Site differences in soil depth and grazing intensity were often more important than treatment effects. We suspect that the unusually dry conditions in the first two growing seasons inhibited

  14. Effectiveness assessment of soil conservation measures in reducing soil erosion in Baiquan County of Northeastern China by using (137)Cs techniques.

    Science.gov (United States)

    Zhang, Qing-Wen; Li, Yong

    2014-05-01

    Accelerated soil erosion is considered as a major land degradation process resulting in increased sediment production and sediment-associated nutrient inputs to the rivers. Over the last decade, several soil conservation programs for erosion control have been conducted throughout Northeastern China. Reliable information on soil erosion rates is an essential prerequisite to assess the effectiveness of soil conservation measures. A study was carried out in Baiquan County of Northeastern China to assess the effectiveness of soil conservation measures in reducing soil erosion using the (137)Cs tracer technique and related techniques. This study reports the use of (137)Cs measurements to quantify medium-term soil erosion rates in traditional slope farmland, contour cropping farmland and terrace farmland in the Dingjiagou catchment and the Xingsheng catchment of Baiquan County. The (137)Cs reference inventory of 2532 ± 670 Bq m(-2) was determined. Based on the principle of the (137)Cs tracer technique, soil erosion rates were estimated. The results showed that severe erosion on traditional slope farmland is the dominant soil erosion process in the area. The terrace measure reduced soil erosion rates by 16% for the entire slope. Typical net soil erosion rates are estimated to be 28.97 Mg per hectare per year for traditional slope farmland and 25.04 Mg per hectare per year for terrace farmland in the Dingjiagou catchment. In contrast to traditional slope farmland with a soil erosion rate of 34.65 Mg per hectare per year, contour cultivation reduced the soil erosion rate by 53% resulting in a soil erosion rate of 22.58 Mg per hectare per year in the Xingsheng catchment. These results indicated that soil losses can be controlled by changing tillage practices from the traditional slope farmland cultivation to the terrace or contour cultivation.

  15. Experimental soil warming effects on C, N, and major element cycling in a low elevation spruce-fir forest soil

    Science.gov (United States)

    Lindsey E. Rustad; Ivan J. Fernandez; Stephanie Arnold

    1996-01-01

    The effect of global warming on north temperate and boreal forest soils has been the subject of much recent debate. These soils serve as major reservoirs for C, N, and other nutrients necessary for forest growth and productivity. Given the uncertainties in estimates of organic matter turnover rates and storage, it is unclear whether these soils will serve as short or...

  16. Soil Moisture Active Passive (SMAP) Mission Level 4 Surface and Root Zone Soil Moisture (L4_SM) Product Specification Document

    Science.gov (United States)

    Reichle, Rolf H.; Ardizzone, Joseph V.; Kim, Gi-Kong; Lucchesi, Robert A.; Smith, Edmond B.; Weiss, Barry H.

    2015-01-01

    This is the Product Specification Document (PSD) for Level 4 Surface and Root Zone Soil Moisture (L4_SM) data for the Science Data System (SDS) of the Soil Moisture Active Passive (SMAP) project. The L4_SM data product provides estimates of land surface conditions based on the assimilation of SMAP observations into a customized version of the NASA Goddard Earth Observing System, Version 5 (GEOS-5) land data assimilation system (LDAS). This document applies to any standard L4_SM data product generated by the SMAP Project. The Soil Moisture Active Passive (SMAP) mission will enhance the accuracy and the resolution of space-based measurements of terrestrial soil moisture and freeze-thaw state. SMAP data products will have a noteworthy impact on multiple relevant and current Earth Science endeavors. These include: Understanding of the processes that link the terrestrial water, the energy and the carbon cycles, Estimations of global water and energy fluxes over the land surfaces, Quantification of the net carbon flux in boreal landscapes Forecast skill of both weather and climate, Predictions and monitoring of natural disasters including floods, landslides and droughts, and Predictions of agricultural productivity. To provide these data, the SMAP mission will deploy a satellite observatory in a near polar, sun synchronous orbit. The observatory will house an L-band radiometer that operates at 1.40 GHz and an L-band radar that operates at 1.26 GHz. The instruments will share a rotating reflector antenna with a 6 meter aperture that scans over a 1000 km swath.

  17. Modeling for Dose Rate Calculation of the External Exposure to Gamma Emitters in Soil

    International Nuclear Information System (INIS)

    Allam, K. A.; El-Mongy, S. A.; El-Tahawy, M. S.; Mohsen, M. A.

    2004-01-01

    Based on the model proposed and developed in Ph.D thesis of the first author of this work, the dose rate conversion factors (absorbed dose rate in air per specific activity of soil in nGy.hr - 1 per Bq.kg - 1) are calculated 1 m above the ground for photon emitters of natural radionuclides uniformly distributed in the soil. This new and simple dose rate calculation software was used for calculation of the dose rate in air 1 m above the ground. Then the results were compared with those obtained by five different groups. Although the developed model is extremely simple, the obtained results of calculations, based on this model, show excellent agreement with those obtained by the above-mentioned models specially that one adopted by UNSCEAR. (authors)

  18. Use of cesium-137 to assess soil erosion rates under soybean, coffee and pasture

    International Nuclear Information System (INIS)

    Andrello, A.C.; Appoloni, C.R.; Guimaraes, M.F.

    2003-01-01

    The methodology cesium-137 was used to assess soil erosion and deposition rates in a small watershed with varied crops, at 23 deg 16' S and 51 deg 17' W, in a district of Cambe, Parana State, Brazil. A theoretical equation which considers soil loss or gain directly proportional to the cesium-137 redistribution was utilized in this study. In the watershed, soil redistribution was assessed by transect sampling, and the regional input of cesium-137 by radioactive rainfall determined based on samples from a point in the native forest. Most sampled pasture points presented soil loss, as well as the points in the soybean area under conventional tillage, while in the coffee crop there was neither soil loss nor gain. (author)

  19. [Characteristics of Phthalic Acid Esters in Agricultural Soils and Products in Areas of Zhongshan City, South China].

    Science.gov (United States)

    Li, Bin; Wu, Shan; Liang, Jin-ming; Liang, Wen-li; Chen, Gui-xian; Li, Yong-jun; Yang, Guo-yi

    2015-06-01

    In order to investigate and assess the pollution level of phthalic acid esters (PAEs) in farm soils and products from typical agricultural fields in areas of Zhongshan City, Guangdong Province, South China, 65 topsoil and 37 agricultural product samples were collected and contents of 6 PAEs compounds that classified by the U. S. Environmental Protection Agency (EPA) as priority pollutants were determined by the GC-FID. The results indicated that total contents of the PAEs (∑ PAEs) in soils ranged from 0. 14 to 1. 14 mg x kg(-1), and the mean value was 0.43 mg x kg(-1), with the detected ratio of 100%. Various concentrations of PAEs differed in three land-use types were ordered by vegetable soil > orchard soil > paddy soil. Comparing with six U.S. EPA priority pollutants of PAEs, the contents of Di-n-butyl phthalate (DBP) and Dimethyl phthalate ( DMP) in soils exceeded the control limits of PAEs in the American soil by 93.85% and 27.69% respectively, but the rest four PAEs compounds were lower than the control limits. Generally, the pollution level of soils contaminated by PAEs in agricultural fields of Zhongshan City was relatively low. The contents of 3 PAEs in agricultural products ranged from 0.15 to 3.15 mg x kg(-1) with the average of 1.12 mg x kg(-1), which was lower than the suggested standards in USA and Europe and with low health risk. Meanwhile, ∑ PAEs concentrations in vegetables were higher than those both in rice and fruits. DBP and DEHP were the main components of PAEs both in agricultural soils and products, with higher percentage contents and detected ratio. ∑ PAEs and DBP contents in various agricultural products-soils had a significantly positive correlation, with Pearson coefficients (r) in vegetables-vegetable soils were 0.81 (P = 0.000), 0.75 (P = 0.000), and corresponding r among rice-paddy soil and fruits-fruit soils were 0.74 (P = 0.036), 0.65 (P = 0.041) and 0.66 (P = 0.029), 0.78 (P = 0.045), respectively. Although there existed a

  20. Using "1"3"7Cs measurements to estimate soil erosion rates in the Pčinja and South Morava River Basins, southeastern Serbia

    International Nuclear Information System (INIS)

    Petrović, Jelena; Dragović, Snežana; Dragović, Ranko; Đorđević, Milan; Đokić, Mrđan; Zlatković, Bojan; Walling, Desmond

    2016-01-01

    The need for reliable assessments of soil erosion rates in Serbia has directed attention to the potential for using "1"3"7Cs measurements to derive estimates of soil redistribution rates. Since, to date, this approach has not been applied in southeastern Serbia, a reconnaissance study was undertaken to confirm its viability. The need to take account of the occurrence of substantial Chernobyl fallout was seen as a potential problem. Samples for "1"3"7Cs measurement were collected from a zone of uncultivated soils in the watersheds of Pčinja and South Morava Rivers, an area with known high soil erosion rates. Two theoretical conversion models, the profile distribution (PD) model and diffusion and migration (D&M) model were used to derive estimates of soil erosion and deposition rates from the "1"3"7Cs measurements. The estimates of soil redistribution rates derived by using the PD and D&M models were found to differ substantially and this difference was ascribed to the assumptions of the simpler PD model that cause it to overestimate rates of soil loss. The results provided by the D&M model were judged to more reliable. - Highlights: • The "1"3"7Cs measurements are employed to estimate the soil erosion and deposition rates in southeastern Serbia. • Estimates of annual soil loss by profile distribution (PD) and diffusion and migration (D&M) models differ significantly. • Differences were ascribed to the assumptions of the simpler PD model which cause it to overestimate rates of soil loss. • The study confirmed the potential for using "1"3"7Cs measurements to estimate soil erosion rates in Serbia.

  1. An inverse analysis reveals limitations of the soil-CO2 profile method to calculate CO2 production and efflux for well-structured soils

    Directory of Open Access Journals (Sweden)

    M. D. Corre

    2010-08-01

    Full Text Available Soil respiration is the second largest flux in the global carbon cycle, yet the underlying below-ground process, carbon dioxide (CO2 production, is not well understood because it can not be measured in the field. CO2 production has frequently been calculated from the vertical CO2 diffusive flux divergence, known as "soil-CO2 profile method". This relatively simple model requires knowledge of soil CO2 concentration profiles and soil diffusive properties. Application of the method for a tropical lowland forest soil in Panama gave inconsistent results when using diffusion coefficients (D calculated based on relationships with soil porosity and moisture ("physically modeled" D. Our objective was to investigate whether these inconsistencies were related to (1 the applied interpolation and solution methods and/or (2 uncertainties in the physically modeled profile of D. First, we show that the calculated CO2 production strongly depends on the function used to interpolate between measured CO2 concentrations. Secondly, using an inverse analysis of the soil-CO2 profile method, we deduce which D would be required to explain the observed CO2 concentrations, assuming the model perception is valid. In the top soil, this inversely modeled D closely resembled the physically modeled D. In the deep soil, however, the inversely modeled D increased sharply while the physically modeled D did not. When imposing a constraint during the fit parameter optimization, a solution could be found where this deviation between the physically and inversely modeled D disappeared. A radon (Rn mass balance model, in which diffusion was calculated based on the physically modeled or constrained inversely modeled D, simulated observed Rn profiles reasonably well. However, the CO2 concentrations which corresponded to the constrained inversely modeled D were too small compared to the measurements. We suggest that, in well-structured soils, a missing description of steady state CO2

  2. Biochar amendment improves soil fertility and productivity of mulberry plant

    Directory of Open Access Journals (Sweden)

    Faruque Ahmed

    2017-07-01

    Full Text Available Biochar has the potential to improve soil fertility and crop productivity. A field experiment was carried out at the experimental field of Bangladesh Sericulture Research and Training Institute (BSRTI, Rajshahi, Bangladesh. The objective of this study was to examine the effect of biochar on soil properties, growth, yield and foliar disease incidence of mulberry plant. The study consisted of 6 treatments: control, basal dose of NPK, rice husk biochar, mineral enriched biochar, basal dose + rice husk biochar and basal dose + mineral enriched biochar. Growth parameters such as node/meter, total branch number/plant, total leaf yield/hectare/year were significantly increased in basal dose + mineral enriched biochar treated plot in second year compared with the other fertilizer treatments. In second year, the total leaf yield/hectare/year were also 142.1% and 115.9% higher in combined application of basal dose + mineral enriched biochar and basal dose + rice husk biochar, respectively, than the control treatment. The soil properties such as organic matter, phosphorus, sulphur and zinc percentage were significantly increased with both the (mineral enriched and rice husk biochar treated soil applied with or without recommended basal dose of NPK than the control and only the recommended basal dose of NPK, respectively. Further, the lowest incidences of tukra (6.4%, powdery mildew (10.4% and leaf spot (7.6% disease were observed in second year under mineral enriched biochar treated plot than the others. The findings revealed that utilization of biochar has positive effect on the improvement of soil fertility and productivity as well as disease suppression of mulberry plant.

  3. Atmospheric production rate of {sup 36}Cl

    Energy Technology Data Exchange (ETDEWEB)

    Parrat, Y.; Hajdas, W.; Baltensperger, U.; Synal, H.A.; Kubik, P.W.; Gaeggeler, H.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Suter, M. [Eidgenoessische Technische Hochschule, Zurich (Switzerland)

    1997-09-01

    Using experimental cross sections, a new calculation of the atmospheric production rate of {sup 36}Cl was carried out. A mean production rate of 20 atoms m{sup -2}s{sup -1} was obtained, which is lower than mean {sup 36}Cl deposition rates. (author) 2 figs., 7 refs.

  4. Isotopic dilution methods to determine the gross transformation rates of nitrogen, phosphorus, and sulfur in soil: a review of the theory, methodologies, and limitations

    International Nuclear Information System (INIS)

    Di, H. J.; Cameron, K. C.; McLaren, R. G.

    2000-01-01

    The rates at which nutrients are released to, and removed from, the mineral nutrient pool are important in regulating the nutrient supply to plants. These nutrient transformation rates need to be taken into account when developing nutrient management strategies for economical and sustainable production. A method that is gaining popularity for determining the gross transformation rates of nutrients in the soil is the isotopic dilution technique. The technique involves labelling a soil mineral nutrient pool, e.g. NH 4 + , NO 3 - , PO 4 3- , or SO 4 2- , and monitoring the changes with time of the size of the labelled nutrient pool and the excess tracer abundance (atom %, if stable isotope tracer is used) or specific activity (if radioisotope is used) in the nutrient pool. Because of the complexity of the concepts and procedures involved, the method has sometimes been used incorrectly, and results misinterpreted. This paper discusses the isotopic dilution technique, including the theoretical background, the methodologies to determine the gross flux rates of nitrogen, phosphorus, and sulfur, and the limitations of the technique. The assumptions, conceptual models, experimental procedures, and compounding factors are discussed. Possible effects on the results by factors such as the uniformity of tracer distribution in the soil, changes in soil moisture content, substrate concentration, and aeration status, and duration of the experiment are also discussed. The influx and out-flux transformation rates derived from this technique are often contributed by several processes simultaneously, and thus cannot always be attributed to a particular nutrient transformation process. Despite the various constraints or possible compounding factors, the technique is a valuable tool that can provide important quantitative information on nutrient dynamics in the soil-plant system. Copyright (2000) CSIRO Publishing

  5. Best management practices: Managing cropping systems for soil protection and bioenergy production

    Science.gov (United States)

    Interest in renewable alternatives to fossil fuels has increased. Crop residue such as corn stover or wheat straw can be used for bioenergy including a substitution for natural gas or coal. Harvesting crop residue needs to be managed to protect the soil and future soil productivity. The amount of bi...

  6. Deposition rates of atmospheric particulates determined from 210Pb measurements in soils and air

    International Nuclear Information System (INIS)

    Likuku, A. S.; Branford, D.

    2011-01-01

    Deposition rates of atmospheric particles were determined using previously published 210P b data in soils and air. The dry deposition velocities for moorland and woodland soils were 2.2 ± 1.8 and 9 ± 2 mm · s - 1 , respectively. The 210P b concentration in rain was calculated to be 94 ± 10 mBq · L - 1. The large (∼ 4 times) deposition velocities in woodland relative to moorland soils is an indication of the degree of accumulation of particles, and most possibly contaminants within woodland soils, which is of practical importance in the mitigation of pollutant concentrations in urban areas by planting trees. (authors)

  7. Soil fertility management: Impacts on soil macrofauna, soil aggregation and soil organic matter allocation.

    NARCIS (Netherlands)

    Ayuke, F.O.; Brussaard, L.; Vanlauwe, B.; Six, J.; Lelei, D.K.; Kibunja, C.N.; Pulleman, M.M.

    2011-01-01

    Maintenance of soil organic matter through integrated soil fertility management is important for soil quality and agricultural productivity, and for the persistence of soil faunal diversity and biomass. Little is known about the interactive effects of soil fertility management and soil macrofauna

  8. Optimising stocking rate and grazing management to enhance environmental and production outcomes for native temperate grasslands

    Science.gov (United States)

    Badgery, Warwick; Zhang, Yingjun; Huang, Ding; Broadfoot, Kim; Kemp, David; Mitchell, David

    2015-04-01

    Stocking rate and grazing management can be altered to enhance the sustainable production of grasslands but the relative influence of each has not often been determined for native temperate grasslands. Grazing management can range from seasonal rests through to intensive rotational grazing involving >30 paddocks. In large scale grazing, it can be difficult to segregate the influence of grazing pressure from the timing of utilisation. Moreover, relative grazing pressure can change between years as seasonal conditions influence grassland production compared to the relative constant requirements of animals. This paper reports on two studies in temperate native grasslands of northern China and south eastern Australia that examined stocking rate and regionally relevant grazing management strategies. In China, the grazing experiment involved combinations of a rest, moderate or heavy grazing pressure of sheep in spring, then moderate or heavy grazing in summer and autumn. Moderate grazing pressure at 50% of the current district average, resulted in the better balance between maintaining productive and diverse grasslands, a profitable livestock system, and mitigation of greenhouse gases through increased soil carbon, methane uptake by the soil, and efficient methane emissions per unit of weight gain. Spring rests best maintained a desirable grassland composition, but had few other benefits and reduced livestock productivity due to lower feed quality from grazing later in the season. In Australia, the grazing experiment compared continuous grazing to flexible 4- and 20-paddock rotational grazing systems with sheep. Stocking rates were adjusted between systems biannually based on the average herbage mass of the grassland. No treatment degraded the perennial pasture composition, but ground cover was maintained at higher levels in the 20-paddock system even though this treatment had a higher stocking rate. Overall there was little difference in livestock production (e.g. kg

  9. Effects of plastic mulches and high tunnel raspberry production systems on soil physicochemical quality indicators

    Science.gov (United States)

    Domagała-Świątkiewicz, Iwona; Siwek, Piotr

    2018-01-01

    In horticulture, degradable materials are desirable alternatives to plastic films. Our aim was to study the impact of soil plastic mulching on the soil properties in the high tunnel and open field production systems of raspberry. The raised beds were mulched with a polypropylene non-woven and two degradable mulches: polypropylene with a photodegradant and non-woven polylactide. The results indicated that the system of raspberry production, as well as the type of mulching had significant impact on soil organic carbon stock, moisture content and water stable aggregate amount. Soils taken from the open field system had a lower bulk density and water stability aggregation index, but higher organic carbon and capillary water content as compared to soils collected from high tunnel conditions. In comparison with the open field system, soil salinity was also found to be higher in high tunnel, as well as with higher P, Mg, Ca, S, Na and B content. Furthermore, mulch covered soils had more organic carbon amount than the bare soils. Soil mulching also enhanced the water capacity expressed as a volume of capillary water content. In addition, mulching improved the soil structure in relation to the bare soil, in particular, in open field conditions. The impact of the compared mulches on soil quality indicators was similar.

  10. Utilization of grasses for potential biofuel production and phytoremediation of heavy metal contaminated soils.

    Science.gov (United States)

    Balsamo, Ronald A; Kelly, William J; Satrio, Justinus A; Ruiz-Felix, M Nydia; Fetterman, Marisa; Wynn, Rodd; Hagel, Kristen

    2015-01-01

    This research focuses on investigating the use of common biofuel grasses to assess their potential as agents of long-term remediation of contaminated soils using lead as a model heavy metal ion. We present evidence demonstrating that switch grass and Timothy grass may be potentially useful for long-term phytoremediation of heavy metal contaminated soils and describe novel techniques to track and remove contaminants from inception to useful product. Enzymatic digestion and thermochemical approaches are being used to convert this lignocellulosic feedstock into useful product (sugars, ethanol, biocrude oil+biochar). Preliminary studies on enzymatic hydrolysis and fast pyrolysis of the Switchgrass materials that were grown in heavy metal contaminated soil and non-contaminated soils show that the presence of lead in the Switchgrass material feedstock does not adversely affect the outcomes of the conversion processes. These results indicate that the modest levels of contaminant uptake allow these grass species to serve as phytoremediation agents as well as feedstocks for biofuel production in areas degraded by industrial pollution.

  11. A Preliminary Study on Termite Mound Soil as Agricultural Soil for Crop Production in South West, Nigeria

    OpenAIRE

    Omofunmi, O. E.; Kolo, J. G.; Alli, A. A.; Ojo, A. S.

    2017-01-01

    It is a popular belief of the people in the Southern region of Nigeria that a land infested with termite usually brings prosperity to the land owner regardless of the type of its usage.  Therefore, the present study assessed termite mounds soil properties which are important to crop production. Two soil samples were collected and their physical and chemical properties determined in accordance with American Public Health Association (APHA, 2005). Data were analyzed using descriptive stati...

  12. Gasification biochar as a valuable by-product for carbon sequestration and soil amendment

    DEFF Research Database (Denmark)

    Hansen, Veronika; Müller-Stöver, Dorette Sophie; Ahrenfeldt, Jesper

    2015-01-01

    Thermal gasification of various biomass residues is a promising technology for combining bioenergy production with soil fertility management through the application of the resulting biochar as soil amendment. In this study, we investigated gasification biochar (GB) materials originating from two ...

  13. Influence of Lime and Phosphorus Application Rates on Growth of Maize in an Acid Soil

    Directory of Open Access Journals (Sweden)

    Peter Asbon Opala

    2017-01-01

    Full Text Available The interactive effects of lime and phosphorus on maize growth in an acid soil were investigated in a greenhouse experiment. A completely randomized design with 12 treatments consisting of four lime levels, 0, 2, 10, and 20 t ha−1, in a factorial combination with three phosphorus rates, 0, 30, and 100 kg ha−1, was used. Maize was grown in pots for six weeks and its heights and dry matter yield were determined and soils were analyzed for available P and exchangeable acidity. Liming significantly reduced the exchangeable acidity in the soils. The effect of lime on available P was not significant but available P increased with increasing P rates. There was a significant effect of lime, P, and P by lime interactions on plant heights and dry matter. Without lime application, dry matter increased with increasing P rates but, with lime, dry mattes increased from 0 to 30 kg P ha−1 but declined from 30 to 100 kg P ha−1. The highest dry matter yield (13.8 g pot−1 was obtained with a combined 2 t ha−1 of lime with 30 kg P ha−1 suggesting that lime application at low rates combined with moderate amounts of P would be appropriate in this soil.

  14. Acid drainage from coal mining: Effect on paddy soil and productivity of rice.

    Science.gov (United States)

    Choudhury, Burhan U; Malang, Akbar; Webster, Richard; Mohapatra, Kamal P; Verma, Bibhash C; Kumar, Manoj; Das, Anup; Islam, Mokidul; Hazarika, Samarendra

    2017-04-01

    Overburden and acid drainage from coal mining is transforming productive agricultural lands to unproductive wasteland in some parts of Northeast India. We have investigated the adverse effects of acid mine drainage on the soil of rice paddy and productivity by comparing them with non-mined land and abandoned paddy fields of Jaintia Hills in Northeast India. Pot experiments with a local rice cultivar (Myngoi) as test crop evaluated biological productivity of the contaminated soil. Contamination from overburden and acid mine drainage acidified the soil by 0.5 pH units, increased the exchangeable Al 3+ content 2-fold and its saturation on clay complexes by 53%. Available sulfur and extractable heavy metals, namely Fe, Mn and Cu increased several-fold in excess of critical limits, while the availability of phosphorus, potassium and zinc contents diminished by 32-62%. The grain yield of rice was 62% less from fields contaminated with acid mine drainage than from fields that have not suffered. Similarly, the amounts of vegetation, i.e. shoots and roots, in pots filled with soil from fields that received acid mine drainage were 59-68% less than from uncontaminated land (average shoot weight: 7.9±2.12gpot -1 ; average root weight: 3.40±1.15gpot -1 ). Paddy fields recovered some of their productivity 4years after mining ceased. Step-wise multiple regression analysis affirmed that shoot weight in the pots and grain yield in field were significantly (p<0.01) and positively influenced by the soil's pH and its contents of K, N and Zn, while concentration of S in excess of threshold limits in contaminated soil significantly (p<0.01) reduced the weight of shoots in the pots and grain yield in the field. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Measurement of radon exhalation rate and soil gas radon concentration in areas of southern Punjab (Pakistan)

    International Nuclear Information System (INIS)

    Mujahid, S. A.; Hussain, S.; Ramzan, M.

    2010-01-01

    Plastic track detectors were used to measure the radon concentration and exhalation rate from the soil samples. The samples were collected from areas of southern Punjab (Pakistan). In a laboratory experiment, passive alpha dosemeters were installed inside cylindrical bottles containing the soil samples. The radon concentrations and the radon exhalation rate were found in the ranges of 34±7 to 260±42 Bq m -3 and 38±8 to 288±46 mBq m -2 h -1 , respectively. The on-site measurements of radon in the soil gas were also carried out in these areas using a scintillation alpha counter. The concentration of radon in the soil gas was found in the range of 423±82-3565±438 Bq m -3 . (authors)

  16. Soil properties and clover establishment six years after surface application of calcium-rich by-products

    Energy Technology Data Exchange (ETDEWEB)

    Ritchey, K.D.; Belesky, D.P.; Halvorson, J.J. [USDA ARS, Beaver, WV (US). Appalachian Farming Systems Research Center

    2004-12-01

    Calcium-rich soil amendments can improve plant growth by supplying Ca and reducing detrimental effects of soil acidity, but solubility and neutralizing capacity of Ca sources vary. Our objectives were to evaluate effects of calcitic dolomite and several coal combustion by-products on soil properties at various depths 6 yr after surface application and their influence on grass-clover herbage accumulation. Calcium and Mg soil amendments were surface-applied to an acidic grassland in 1993, and orchardgrass (Dactylis glomerata L.) and tall fescue (Lolium arundinaceum (Schreb.) Darbyshire) were oversown in 1994. In 1998, amendment treatment plots were split to accommodate sod seeding with red clover (Trifolium pratense L.) or white clover (T. repens L.) as well as a nonseeded control. No N fertilizer was applied after sod seeding. Six years after amendment application, reductions in soil Al and Mn and increases in Ca and pH from 4654 kg ha{sup -1} calcitic dolomite, 15 000 kg ha{sup -1} fluidized bed combustion residue, or 526 kg ha{sup -1} MgO amendment were greatest in the surface 2.5 cm while rates of gypsum as high as 32 000 kg ha{sup -1} left little residual effect except for decreases in Mg. Percentage clover in the sward tripled as pH increased from 4.3 to 5.0 while herbage mass increased 75% as clover percentage increased. Herbage mass was generally more closely correlated with properties of soil samples collected from the surface 2.5 cm than from deeper samples.

  17. Estimation of soil respiration rates and soil gas isotopic composition for the different land use of Ultisols from Calhoun CZO.

    Science.gov (United States)

    Cherkinsky, A.; Brecheisen, Z.; Richter, D. D., Jr.; Sheng, H.

    2017-12-01

    CO2 flux from soil is significant in most ecosystems and can account for more than 2/3 of total ecosystem respiration. In many cases CO2 fluxes from soil are estimated using eddy covariance techniques or the classical chamber method with measures of bulk concentrations and isotope composition of CO2. Whereas most of these studies estimate flux from the soil surface, we analyzed its concentration and isotope composition directly in soil profiles down to 8.5m depth. This experiment was conducted in Sumter National Forest in summer of 2016. The samples were collected from 3 different land use history sites: a) reference hardwood stands, mainly of oak and hickory that are taken to be never cultivated; b) cultivated plots, which were also used growing cotton prior to the 1950's but for the last 50 years for growing corn, wheat, legume, sorghum, and sunflowers; c) pine stands, which had been used for growing cotton from beginning of the 19th century and then was abandoned in 1920s and planted with loblolly pine. We have analyzed 3 replicates of each land use. There were measured in the field CO2 and O2 concentration and collected gas samples were analyzed for Δ14C, δ13C and δ18O. CO2 concentration in all types of land use has a maximum about 3m depth, approximately the same depth as the minimum of O2 concentration. Isotope analyses revealed that carbon isotopic composition tend to become lighter with the depth for all three types of land use: in cultivated site it changes from -18%o at 0.5m to -21%o at 5m; in pine site from -22%o to -25%o and in hardwood from-21.5 -24.5%o correspondently, the O2 isotopic composition does not change significantly. Based on analysis of Δ14C the turnover rate of CO2 is getting slower as depth increases. At the first 50 cm the exchange rate is the fastest on cultivated site, likely due to annual tilling, and concentration of 14C is actually equal to atmospheric. However, the turnover rate of Δ14C in soil CO2 slows down significantly as

  18. [Estimate the abatement rate of septic tank sewage outfall soil on nitrogen pollutants of typical farmer household sewage].

    Science.gov (United States)

    Zhou, Feng; Wang, Wen-Lin; Wang, Guo-Xiang; Ma, Jiu-Yuan; Wan, Yin-Jing; Tang, Xiao-Yan; Liang, Bin; Ji, Bin

    2013-10-01

    The surface soil on sewage outfall and effluent of farmer household septic tank were collected in situ from the typical region of plain river network areas in Taihu Lake Basin, and the typical rainfall (summer 30 mm . times-1, winter 5 mm times -1), temperature (summer 27 degrees C, winter 5 degrees C ) condition and pollutant load were artificial simulated by indoor simulation soil column experiments for estimating nitrogen abatement rate of rural sewage treated by the outfall soil and exploring the abatement rule in different seasons and weather process (7 days before the rain, 3 rainy days, 7 days after the rain). Results showed that: there was the significant difference (P 0. 05). Therefore, the TN, NH+4 -N abatement rate, NO-3 -N increase rate need to be divided by seasons, TN abatement rate, NO-3 -N increase rate of summer need to be divided by the weather process, which were 38.5% , - 25.0% , 46. 0% and 478. 1%, 913.8%, 382. 0% , before the rain, in rainy day, after the rain, respectively; while the NH+4 -N abatement rate of summer and the TN, NH+4 -N abatement rate, NO-3 -N increase rate of winter do not need to be divided by weather process, were 91.7% , 50.4% , 85.5% and 276.0% , respectively. In the summer, the TN abatement rate in different weather processes was not correlated with NH+4 -N abatement rate, but significantly negative correlated with NO-3 -N increase rate. In the winter, the stable accumulation of TN in soil was an important reason of the TN abatement rate which had no significant difference and kept a high level among different weather processes, and it was closely related to the stable accumulation of NH+4 -N in soil.

  19. Using high-resolution soil moisture modelling to assess the uncertainty of microwave remotely sensed soil moisture products at the correct spatial and temporal support

    Science.gov (United States)

    Wanders, N.; Karssenberg, D.; Bierkens, M. F. P.; Van Dam, J. C.; De Jong, S. M.

    2012-04-01

    Soil moisture is a key variable in the hydrological cycle and important in hydrological modelling. When assimilating soil moisture into flood forecasting models, the improvement of forecasting skills depends on the ability to accurately estimate the spatial and temporal patterns of soil moisture content throughout the river basin. Space-borne remote sensing may provide this information with a high temporal and spatial resolution and with a global coverage. Currently three microwave soil moisture products are available: AMSR-E, ASCAT and SMOS. The quality of these satellite-based products is often assessed by comparing them with in-situ observations of soil moisture. This comparison is however hampered by the difference in spatial and temporal support (i.e., resolution, scale), because the spatial resolution of microwave satellites is rather low compared to in-situ field measurements. Thus, the aim of this study is to derive a method to assess the uncertainty of microwave satellite soil moisture products at the correct spatial support. To overcome the difference in support size between in-situ soil moisture observations and remote sensed soil moisture, we used a stochastic, distributed unsaturated zone model (SWAP, van Dam (2000)) that is upscaled to the support of different satellite products. A detailed assessment of the SWAP model uncertainty is included to ensure that the uncertainty in satellite soil moisture is not overestimated due to an underestimation of the model uncertainty. We simulated unsaturated water flow up to a depth of 1.5m with a vertical resolution of 1 to 10 cm and on a horizontal grid of 1 km2 for the period Jan 2010 - Jun 2011. The SWAP model was first calibrated and validated on in-situ data of the REMEDHUS soil moisture network (Spain). Next, to evaluate the satellite products, the model was run for areas in the proximity of 79 meteorological stations in Spain, where model results were aggregated to the correct support of the satellite

  20. Final Report for DOE grant no. DE-FG02-04ER63883: Can soil genomics predict the impact of precipitation on nitrous oxide flux from soil

    Energy Technology Data Exchange (ETDEWEB)

    Egbert Schwartz

    2008-12-15

    Nitrous oxide is a potent greenhouse gas that is released by microorganisms in soil. However, the production of nitrous oxide in soil is highly variable and difficult to predict. Future climate change may have large impacts on nitrous oxide release through alteration of precipitation patterns. We analyzed DNA extracted from soil in order to uncover relationships between microbial processes, abundance of particular DNA sequences and net nitrous oxide fluxes from soil. Denitrification, a microbial process in which nitrate is used as an electron acceptor, correlated with nitrous oxide flux from soil. The abundance of ammonia oxidizing archaea correlated positively, but weakly, with nitrous oxide production in soil. The abundance of bacterial genes in soil was negatively correlated with gross nitrogen mineralization rates and nitrous oxide release from soil. We suggest that the most important control over nitrous oxide production in soil is the growth and death of microorganisms. When organisms are growing nitrogen is incorporated into their biomass and nitrous oxide flux is low. In contrast, when microorganisms die, due to predation or infection by viruses, inorganic nitrogen is released into the soil resulting in nitrous oxide release. Higher rates of precipitation increase access to microorganisms by predators or viruses through filling large soil pores with water and therefore can lead to large releases of nitrous oxide from soil. We developed a new technique, stable isotope probing with 18O-water, to study growth and mortality of microorganisms in soil.

  1. Biochar amended soils and crop productivity: A critical and meta-analysis of literature

    DEFF Research Database (Denmark)

    Baidoo, Isaac; Sarpong, Daniel Bruce; Bolwig, Simon

    2016-01-01

    Biochar is a kind of charcoal used for soil improvement and it is produced by pyrolysis of biomass under low or anaerobic conditions. It has the potential to mitigate climate change, via carbon sequestration, decrease soil acidity and increase agricultural productivity. Historically it is known...... that the Amazonians used biochar to enhance soil productivity by smoldering agricultural wastes. Desk reviewed of articles of soil amended biochar and some attributes which enhance crop development and the economic benefits derived from its use in agriculture were critically analysed. A meta-analysis using twenty......-seven (27) articles reveal that the temperature at which pyrolysis is done is a major contributing factor towards the intended use of the biochar. For the purpose of crop yield, a temperature of 5500C is recommended based on the regression results. It is recommended that an in-depth study should be done...

  2. Optimizing Productivity of Food Crop Genotypes in Low Nutrient Soils

    International Nuclear Information System (INIS)

    2013-11-01

    Global climate change is likely to exacerbate plant abiotic stress in the coming decades by increasing water stress and by accelerating soil fertility degradation. To respond to this set of challenges, there is a need to develop agricultural systems with significantly greater productivity and resilience that at the same time use limited natural resources more efficiently. Low phosphorus (N) and nitrogen (P) availabilities are primary limitations to productivity in low input agriculture, and fertilizers are primary resource inputs in intensive agriculture. A critical feature of future agricultural systems will be new crop varieties with improved conversion of soil resources to yields. These new cultivars would have improved productivity in low input systems and decreased input requirements in high input systems. Many scientists are currently turning their attention to roots, the hidden half of the plant, as central to their efforts to produce crops with better yields without causing environmental damage. Several root traits are known to be associated with P and N acquisition efficiency in low N and P soils. These root traits include root hairs, root length, root branching and root density. The identification of root traits for enhanced P and N acquisition is enabling crop breeders to develop new genotypes with better yields in low fertility soils of Africa, Asia and Latin America. However, in order to use a trait as a selection criterion for crop improvement, either direct phenotypic selection or through marker assisted selection, it is necessary to develop protocols to measure accurately the root traits that enhance N and P acquisition in the glasshouse and in the field, which can provide robust and rapid evaluation of many root systems' architectural traits in targeted production environments using different crops. The objective of the Coordinated Research Project on Optimizing Productivity of Food Crop Genotypes in Low Nutrient Soils was to develop integrated

  3. Optimizing Productivity of Food Crop Genotypes in Low Nutrient Soils

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-11-15

    Global climate change is likely to exacerbate plant abiotic stress in the coming decades by increasing water stress and by accelerating soil fertility degradation. To respond to this set of challenges, there is a need to develop agricultural systems with significantly greater productivity and resilience that at the same time use limited natural resources more efficiently. Low phosphorus (N) and nitrogen (P) availabilities are primary limitations to productivity in low input agriculture, and fertilizers are primary resource inputs in intensive agriculture. A critical feature of future agricultural systems will be new crop varieties with improved conversion of soil resources to yields. These new cultivars would have improved productivity in low input systems and decreased input requirements in high input systems. Many scientists are currently turning their attention to roots, the hidden half of the plant, as central to their efforts to produce crops with better yields without causing environmental damage. Several root traits are known to be associated with P and N acquisition efficiency in low N and P soils. These root traits include root hairs, root length, root branching and root density. The identification of root traits for enhanced P and N acquisition is enabling crop breeders to develop new genotypes with better yields in low fertility soils of Africa, Asia and Latin America. However, in order to use a trait as a selection criterion for crop improvement, either direct phenotypic selection or through marker assisted selection, it is necessary to develop protocols to measure accurately the root traits that enhance N and P acquisition in the glasshouse and in the field, which can provide robust and rapid evaluation of many root systems' architectural traits in targeted production environments using different crops. The objective of the Coordinated Research Project on Optimizing Productivity of Food Crop Genotypes in Low Nutrient Soils was to develop integrated

  4. Short-Term Responses of Soil Respiration and C-Cycle Enzyme Activities to Additions of Biochar and Urea in a Calcareous Soil.

    Directory of Open Access Journals (Sweden)

    Dali Song

    Full Text Available Biochar (BC addition to soil is a proposed strategy to enhance soil fertility and crop productivity. However, there is limited knowledge regarding responses of soil respiration and C-cycle enzyme activities to BC and nitrogen (N additions in a calcareous soil. A 56-day incubation experiment was conducted to investigate the combined effects of BC addition rates (0, 0.5, 1.0, 2.5 and 5.0% by mass and urea (U application on soil nutrients, soil respiration and C-cycle enzyme activities in a calcareous soil in the North China Plain. Our results showed soil pH values in both U-only and U plus BC treatments significantly decreased within the first 14 days and then stabilized, and CO2emission rate in all U plus BC soils decreased exponentially, while there was no significant difference in the contents of soil total organic carbon (TOC, dissolved organic carbon (DOC, total nitrogen (TN, and C/N ratio in each treatment over time. At each incubation time, soil pH, electrical conductivity (EC, TOC, TN, C/N ratio, DOC and cumulative CO2 emission significantly increased with increasing BC addition rate, while soil potential activities of the four hydrolytic enzymes increased first and then decreased with increasing BC addition rate, with the largest values in the U + 1.0%BC treatment. However, phenol oxidase activity in all U plus BC soils showed a decreasing trend with the increase of BC addition rate. Our results suggest that U plus BC application at a rate of 1% promotes increases in hydrolytic enzymes, does not highly increase C/N and C mineralization, and can improve in soil fertility.

  5. Short-Term Responses of Soil Respiration and C-Cycle Enzyme Activities to Additions of Biochar and Urea in a Calcareous Soil

    Science.gov (United States)

    Song, Dali; Xi, Xiangyin; Huang, Shaomin; Liang, Guoqing; Sun, Jingwen; Zhou, Wei; Wang, Xiubin

    2016-01-01

    Biochar (BC) addition to soil is a proposed strategy to enhance soil fertility and crop productivity. However, there is limited knowledge regarding responses of soil respiration and C-cycle enzyme activities to BC and nitrogen (N) additions in a calcareous soil. A 56-day incubation experiment was conducted to investigate the combined effects of BC addition rates (0, 0.5, 1.0, 2.5 and 5.0% by mass) and urea (U) application on soil nutrients, soil respiration and C-cycle enzyme activities in a calcareous soil in the North China Plain. Our results showed soil pH values in both U-only and U plus BC treatments significantly decreased within the first 14 days and then stabilized, and CO2emission rate in all U plus BC soils decreased exponentially, while there was no significant difference in the contents of soil total organic carbon (TOC), dissolved organic carbon (DOC), total nitrogen (TN), and C/N ratio in each treatment over time. At each incubation time, soil pH, electrical conductivity (EC), TOC, TN, C/N ratio, DOC and cumulative CO2 emission significantly increased with increasing BC addition rate, while soil potential activities of the four hydrolytic enzymes increased first and then decreased with increasing BC addition rate, with the largest values in the U + 1.0%BC treatment. However, phenol oxidase activity in all U plus BC soils showed a decreasing trend with the increase of BC addition rate. Our results suggest that U plus BC application at a rate of 1% promotes increases in hydrolytic enzymes, does not highly increase C/N and C mineralization, and can improve in soil fertility. PMID:27589265

  6. Contamination of the soil along the river Zletovska by metals as by products of economic production of Pb-Zn

    OpenAIRE

    Boev, Blazo; Lepitkova, Sonja

    1996-01-01

    This paper shows the results constraining the degree of contamination of soil along the course of the River Zletovska by some mewls. These are by- products of economic production of lead-zinc ores which are common in this area. Contamination of soils by some metals, first of all by Pb, Zn, Cu, Cd, As, Fe, Al, Mn, Na, K is an important issue for the quality of the environment in which we live from several aspects: accumulation of waters under river alluvions; agricultural produ...

  7. Release of polyaromatic hydrocarbons from coal tar contaminated soils

    International Nuclear Information System (INIS)

    Priddy, N.D.; Lee, L.S.

    1996-01-01

    A variety of process wastes generated from manufactured gas production (MGP) have contaminated soils and groundwater at production and disposal sites. Coal tar, consisting of a complex mixture of hydrocarbons present as a nonaqueous phase liquid, makes up a large portion of MGP wastes. Of the compounds in coal tar, polyaromatic hydrocarbons (PAHs) are the major constituents of environmental concern due to their potential mutagenic and carcinogenic hazards. Characterization of the release of PAHs from the waste-soil matrix is essential to quantifying long-term environmental impacts in soils and groundwater. Currently, conservative estimates for the release of PAHs to the groundwater are made assuming equilibrium conditions and using relationships derived from artificially contaminated soils. Preliminary work suggests that aged coal tar contaminated soils have much lower rates of desorption and a greater affinity for retaining organic contaminants. To obtain better estimates of desorption rates, the release of PAHs from a coal tar soil was investigated using a flow-interruption, miscible displacement technique. Methanol/water solutions were employed to enhance PAH concentrations above limits of detection. For each methanol/water solution employed, a series of flow interrupts of varying times was invoked. Release rates from each methanol/water solution were estimated from the increase in concentration with duration of flow interruption. Aqueous-phase release rates were then estimated by extrapolation using a log-linear cosolvency model

  8. Ecological intensification of cereal production systems: yield potential, soil quality, and precision agriculture.

    Science.gov (United States)

    Cassman, K G

    1999-05-25

    Wheat (Triticum aestivum L.), rice (Oryza sativa L.), and maize (Zea mays L.) provide about two-thirds of all energy in human diets, and four major cropping systems in which these cereals are grown represent the foundation of human food supply. Yield per unit time and land has increased markedly during the past 30 years in these systems, a result of intensified crop management involving improved germplasm, greater inputs of fertilizer, production of two or more crops per year on the same piece of land, and irrigation. Meeting future food demand while minimizing expansion of cultivated area primarily will depend on continued intensification of these same four systems. The manner in which further intensification is achieved, however, will differ markedly from the past because the exploitable gap between average farm yields and genetic yield potential is closing. At present, the rate of increase in yield potential is much less than the expected increase in demand. Hence, average farm yields must reach 70-80% of the yield potential ceiling within 30 years in each of these major cereal systems. Achieving consistent production at these high levels without causing environmental damage requires improvements in soil quality and precise management of all production factors in time and space. The scope of the scientific challenge related to these objectives is discussed. It is concluded that major scientific breakthroughs must occur in basic plant physiology, ecophysiology, agroecology, and soil science to achieve the ecological intensification that is needed to meet the expected increase in food demand.

  9. Reductions in soil surface albedo as a function of biochar application rate: implications for global radiative forcing

    International Nuclear Information System (INIS)

    Verheijen, Frank G A; Bastos, Ana Catarina; Keizer, Jan Jacob; Jeffery, Simon; Van der Velde, Marijn; Penížek, Vít; Beland, Martin

    2013-01-01

    Biochar can be defined as pyrolysed (charred) biomass produced for application to soils with the aim of mitigating global climate change while improving soil functions. Sustainable biochar application to soils has been estimated to reduce global greenhouse gas emissions by 71–130 Pg CO 2 -C e over 100 years, indicating an important potential to mitigate climate change. However, these estimates ignored changes in soil surface reflection by the application of dark-coloured biochar. Through a laboratory experiment we show a strong tendency for soil surface albedo to decrease as a power decay function with increasing biochar application rate, depending on soil moisture content, biochar application method and land use. Surface application of biochar resulted in strong reductions in soil surface albedo even at relatively low application rates. As a first assessment of the implications for climate change mitigation of these biochar–albedo relationships, we applied a first order global energy balance model to compare negative radiative forcings (from avoided CO 2 emissions) with positive radiative forcings (from reduced soil surface albedos). For a global-scale biochar application equivalent to 120 t ha −1 , we obtained reductions in negative radiative forcings of 5 and 11% for croplands and 11 and 23% for grasslands, when incorporating biochar into the topsoil or applying it to the soil surface, respectively. For a lower global biochar application rate (equivalent to 10 t ha −1 ), these reductions amounted to 13 and 44% for croplands and 28 and 94% for grasslands. Thus, our findings revealed the importance of including changes in soil surface albedo in studies assessing the net climate change mitigation potential of biochar, and we discuss the urgent need for field studies and more detailed spatiotemporal modelling. (letter)

  10. Cesium-137 in soils and its soil-to-plant transfer rate

    International Nuclear Information System (INIS)

    Papastefanou, C.; Manolopoulou, M.; Charalambous, S.

    1988-01-01

    Measurements of fallout-derived 137 Cs in soils were made in the Valley of Ptolemais, North Greece after the Chernobyl nuclear reactor accident. The 137 Cs concentrations ranged between 290 Bq kg -1 and 7670 Bq kg -1 . It was found that the 137 Cs concentration is inversely proportional to 40 K concentration or potassium content of soils. Cesium-137 transfer coefficients from soil to plants (grass) ranged from 0.02 to 0.2

  11. The SMAP Level 4 Surface and Root-zone Soil Moisture (L4_SM) Product

    Science.gov (United States)

    Reichle, Rolf; Crow, Wade; Koster, Randal; Kimball, John

    2010-01-01

    The Soil Moisture Active and Passive (SMAP) mission is being developed by NASA for launch in 2013 as one of four first-tier missions recommended by the U.S. National Research Council Committee on Earth Science and Applications from Space in 2007. The primary science objectives of SMAP are to enhance understanding of land surface controls on the water, energy and carbon cycles, and to determine their linkages. Moreover, the high resolution soil moisture mapping provided by SMAP has practical applications in weather and seasonal climate prediction, agriculture, human health, drought and flood decision support. In this paper we describe the assimilation of SMAP observations for the generation of the planned SMAP Level 4 Surface and Root-zone Soil Moisture (L4_SM) product. The SMAP mission makes simultaneous active (radar) and passive (radiometer) measurements in the 1.26-1.43 GHz range (L-band) from a sun-synchronous low-earth orbit. Measurements will be obtained across a 1000 km wide swath using conical scanning at a constant incidence angle (40 deg). The radar resolution varies from 1-3 km over the outer 70% of the swath to about 30 km near the center of the swath. The radiometer resolution is 40 km across the entire swath. The radiometer measurements will allow high-accuracy but coarse resolution (40 km) measurements. The radar measurements will add significantly higher resolution information. The radar is however very sensitive to surface roughness and vegetation structure. The combination of the two measurements allows optimal blending of the advantages of each instrument. SMAP directly observes only surface soil moisture (in the top 5 cm of the soil column). Several of the key applications targeted by SMAP, however, require knowledge of root zone soil moisture (approximately top 1 m of the soil column), which is not directly measured by SMAP. The foremost objective of the SMAP L4_SM product is to fill this gap and provide estimates of root zone soil moisture

  12. Decreased summer drought affects plant productivity and soil carbon dynamics in Mediterranean woodland

    Science.gov (United States)

    Cotrufo, M. F.; Alberti, G.; Inglima, I.; Marjanović, H.; Lecain, D.; Zaldei, A.; Peressotti, A.; Miglietta, F.

    2011-06-01

    Precipitation patterns are expected to change in the Mediterranean region within the next decades, with projected decreases in total rainfall and increases in extreme events. We manipulated precipitation patterns in a Mediterranean woodland, dominated by Arbutus unedo L., to study the effects of changing precipitation regimes on above-ground net primary production (ANPP) and soil C dynamics, specifically plant-derived C input to soil and soil respiration (SR). Experimental plots were exposed to either a 20 % reduction of throughfall or to water addition targeted at maintaining soil water content above a minimum of 10 % v/v. Treatments were compared to control plots which received ambient precipitation. The throughfall manipulation experiment started in 2004 and we report data up to the 2009 growing season. Enhanced soil moisture during summer months highly stimulated annual stem primary production, litter fall, SR and net annual plant-derived C input to soil which on average increased by 130 %, 26 %, 50 % and 220 %, respectively, as compared to control. In contrast, the 20 % reduction in throughfall (equivalent to 10 % reduction of precipitation) did not significantly change soil moisture at the site, and therefore did not significantly affect ANPP or SR. We conclude that minor changes (around 10 % reduction) in precipitation amount are not likely to significantly affect ANPP or soil C dynamics in Mediterranean woodland. However, if summer rain increases, C cycling will significantly accelerate but soil C stocks are not likely to be changed in the short-term. More studies involving modelling of long term C dynamics are needed to predict if the estimated increases in soil C input under wet conditions is going to be sustained and if labile C is being substituted to stable C, with a negative effect on long term soil C stocks.

  13. Impact of Altered Precipitation Patterns on Plant Productivity and Soil Respiration in a Northern Great Plains Grassland

    Science.gov (United States)

    Haase, L.; Flanagan, L. B.

    2017-12-01

    Precipitation patterns are expected to shift towards larger but fewer rain events, with longer intermittent dry periods, associated with climate change. The larger rain events may compensate for and help to mitigate climate change effects on key ecosystem functions such as plant productivity and soil respiration in semi-arid grasslands. We experimentally manipulated the amount and frequency of simulated precipitation added to trenched, treatment plots that were covered by rain shelters, and measured the response in plant productivity and soil respiration in a native, grassland ecosystem near Lethbridge, Alberta. We compared the observed responses to the predictions of a conceptual ecosystem response model developed by Knapp et al. 2008 (BioScience 58: 811-821). Two experiments were conducted during 14 weeks of the growing season from May-August. The first experiment (normal amount) applied total growing season precipitation of 180 mm (climate normal), and the second experiment (reduced amount) applied total precipitation of 90 mm. In both experiments, precipitation was applied at two frequencies, 1 rain event every week (normal frequency) and 1 rain event every two weeks (reduced frequency). In the normal amount experiment, the average rain event was 12.8 mm for the normal frequency treatment and 25.8 mm for the reduced frequency treatment. In the reduced amount experiment, the average rain event was 6.4 mm for the normal frequency treatment and 12.8 mm for the reduced frequency treatment. We hypothesized that larger but fewer rain events would result in increased plant productivity and soil respiration for both experiments. Plant greenness values calculated from digital photographs were used as a proxy for plant productivity, and showed significantly higher values for the normal vs. reduced amount experiment. Soil respiration rate also showed significantly higher values for the normal vs. reduced amount experiment. No significant treatment effect could be detected

  14. The effectiveness of sulfidic materials as a source of sulfur fertilizer for the production of rice in two sulfur deficient soils

    Directory of Open Access Journals (Sweden)

    Abul Hasnat M. Shamim

    2010-12-01

    Full Text Available The effectiveness of sulfidic materials (SM and gypsum (G application at the rates of 0, 40, 80, 120, and 160 kg S ha-1on the growth, yield, and mineral nutrition of rice (Oryza sativa L.; BR 16: Shahi balam cultivated in two sulfur deficient soilsof Sirajgonj (Typic Haplaquept and Gazipur (Typic Paleustult were evaluated in a greenhouse study. The best growth, yieldperformance, and nutrition of rice were recorded by the SM160 treatment in both the Sirajgonj (e.g. grain: 9.8 g/plant andGazipur (8.6 soils, followed by the SM120 (8.5, 7.5 > SM80 (7.3, 7.3 > G160 (7.1, 6.9 treatments. The application of SMincreased the average grain yield by 82% (increased over control: IOC for Sirajgonj soil and 78% for Gazipur soil, irrespectiveof application rates. In the case of gypsum, these increments were 40 and 37% for Sirajgonj and Gazipur soils, respectively. Theapplication of gypsum at the highest rate of G160 was not as effective as even the dose of SM80 in both of the soils. However,almost similar and significant (p<0.05 effects were observed for the grain weight, percent filled grains, and harvest index ofrice grown in both the soils. The applied SM increased the average organic matter and available sulfur contents in the soilsby 20 to 46%, and 140 to 228% IOC, respectively, while these increments were 6 to 20% and 88 to 187% for gypsum treatments,indicating that the SM was potential and effective than gypsum not only as a source of sulfur fertilizer but also to enrich thefertility and productivity status of the soils. Moreover, the SM treatment was found to be maintained the high nutrient statusin both the soils till the final harvest at maturity of rice, reflecting a good indication for its long term use. The use of SM didnot show any adverse effect on the plant and soil.

  15. Soil types and limiting factors in agricultural production in the San Fernando district, Tamaulipas, Mexico

    International Nuclear Information System (INIS)

    Espinosa Ramirez, M.; Garza Cedillo, R.; Andrade limas, E.; Belmonte Serrato, F.

    2009-01-01

    The limiting factors in agricultural production, defined as those properties and characteristics of the geographical environment that influence the development of crops, can be diverse and are grouped with the physical environment of soil. They are the result of soil characteristics and soil degradation processes by anthropogenic influence. Due to the above, the objective of this study was to identify and surveying the limitative factors to agricultural production, as well as to define its ability land use capacity in San Fernando district, Tamaulipas. (Author) 7 refs.

  16. Isotopic techniques to study phosphorus cycling in soils

    International Nuclear Information System (INIS)

    Manjaiah, K.M.; Sreenivasa Chari, M.; Sachdev, P.; Sachdev, M.S.

    2008-01-01

    A sound understanding of phosphorus cycling in soil system is essential in order to manage this system in a sustainable manner. Phosphorus transformations are characterized by physico-chemical (sorption-desorption) and biological processes . The transformation rates need to be taken into account while developing nutrient management strategies for economical and sustainable production. One of the important tools and the method gaining popularity for determining the gross transformation rates of nutrients in the soil is the isotopic dilution technique. The major processes in the soil-plant system which determine the distribution and bioavailability of phosphorus in various inorganic and organic soil components consist of: (1) the dissolution of soil mineral phosphates, (2) retention of phosphorus by inorganic soil constituents, (3) decomposition of organic phosphorus contained in plant, animal and microbial detritus and (4) Immobilization of phosphorus via the soil microbial biomass and plan uptake

  17. Measurement of 222Rn and 220Rn exhalation rate from soil samples of Kumaun Hills, India

    Science.gov (United States)

    Semwal, Poonam; Singh, Kuldeep; Agarwal, T. K.; Joshi, Manish; Pant, Preeti; Kandari, Tushar; Ramola, R. C.

    2018-03-01

    The source terms, i.e., exhalation and emanation from soil and building materials are the primary contributors to the radon (222Rn)/thoron (220Rn) concentration levels in the dwellings, while the ecological constraints like ventilation rate, temperature, pressure, humidity, etc., are the influencing factors. The present study is focused on Almora District of Kumaun, located in Himalayan belt of Uttarakhand, India. For the measurement of 222Rn and 220Rn exhalation rates, 24 soil samples were collected from different locations. Gamma radiation level was measured at each of these locations. Chamber technique associated with Smart Rn Duo portable monitor was employed for the estimation of 222Rn and 220Rn exhalation rates. Radionuclides (226Ra, 232Th and 40K) concentrations were also measured in soil samples using NaI(Tl) scintillation based gamma ray spectrometry. The mass exhalation rate for 222Rn was varying between 16 and 54 mBq/kg/h, while the 220Rn surface exhalation rate was in the range of 0.65-6.43 Bq/m2/s. Measured gamma dose rate for the same region varied from 0.10 to 0.31 µSv/h. Inter-correlation of exhalation rates and intra-correlation with background gamma levels were studied.

  18. Management and conservation of tropical acid soils for sustainable crop production. Proceedings of a consultants meeting

    International Nuclear Information System (INIS)

    2000-06-01

    Forests of the tropics are invaluable ecosystems of global, regional and local importance, particularly in terms of protection and conservation of biodiversity and water resources. The indiscriminate conversion of tropical forests into agricultural land as a result of intense human activities - logging and modem shifting cultivation - continues to cause soil erosion and degradation. However, the acid savannahs of the world, such as the cerrado of Brazil, the Llanos in Venezuela and Colombia, the savannahs of Africa, and the largely anthropic savannahs of tropical Asia, encompass vast areas of potentially arable land. The acid soils of the savannahs are mostly considered marginal because of low inherent fertility and susceptibility to rapid degradation. These constraints for agricultural development are exacerbated by the poverty of new settlers who try to cultivate such areas after deforestation. Low- or minimum-input systems are not sustainable on these tropical acid soils but, with sufficient investment and adequate technologies, they can be highly productive. Thus, there is a need to develop management practices for sustainable agricultural production systems on such savannah acid soils. The Soil and Water Management and Crop Nutrition Sub-programme of the Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture strongly supports an integrated approach to soil, water and nutrient management within cropping systems. In this context, nuclear and related techniques can be used to better understand the processes and factors influencing the productivity of agricultural production systems, and improve them through the use of better soil, water and nutrient management practices. A panel of experts actively engaged in field projects on acid soils of savannah agro-ecosystems in the humid and sub-humid tropics convened in March 1999 in Vienna to review and discuss recent research progress, along the following main lines of investigation: (i) utilization of

  19. Soil respiration and rates of soil carbon turnover differ among six common European tree species

    DEFF Research Database (Denmark)

    Vesterdal, Lars; Elberling, Bo; Christiansen, Jesper Riis

    2012-01-01

    replicated at six sites in Denmark. The studied tree species were the broadleaves beech (Fagus sylvatica L.), pedunculate oak (Quercus robur L.), lime (Tilia cordata L.), sycamore maple (Acer pseudoplatanus L.) and ash (Fraxinus excelsior L.) and the conifer Norway spruce (Picea abies (L.) Karst.). Rates....... Soil respiration differed significantly among several species and increased in the order beechmaple... moisture. Carbon turnover rates based on the ratio between R h and C stock were significantly higher in ash than in all other species except maple, and maple also had higher C turnover than spruce. A similar influence of tree species on C turnover was indicated by the litterfall C to forest floor C ratio...

  20. Temperature versus plant effects on diel dynamics of soil CO2 production and efflux: a controlled environment study

    Science.gov (United States)

    Reinthaler, David; Roy, Jacques; Landais, Damien; Piel, Clement; Resco de Dios, Victor; Bahn, Michael

    2015-04-01

    Soil respiration (Rs) is the biggest source of CO2 emitted from terrestrial ecosystems to the atmosphere. Therefore the understanding of its drivers is of major importance for models of carbon cycling. Next to temperature as a major abiotic factor, photosynthesis has been suggested as an important driver influencing diel patterns in Rs. Under natural conditions it is difficult to disentangle abiotic and biotic effects on soil CO2 production, as fluctuating light intensity affects both photosynthetic activity and soil temperature. To analyse individual and combined effects of soil temperature and light on the dynamics of soil CO2 production and efflux, we performed a controlled environment study at the ECOTRON facility in Montpellier. The study manipulated temperature and photosynthetically active radiation independently and was carried out in large macrocosms, hosting canopies of either a woody (cotton) or a herbaceous (bean) crop. In each macrocosm membrane tubes had been installed across the soil profile for continuous measurement of soil CO2 concentrations. In addition, an automated soil respiration system was installed in each macrocosm, whose data were also used for validating a model of soil CO2 production and transport based on the concentration profiles. Both for cotton and for bean canopies, under conditions of naturally fluctuating temperature and light conditions, soil CO2 production and efflux followed a clear diel pattern. Under constantly dark conditions (excluding immediate effects of photosynthesis) and constant temperature, no significant diel changes in Rs could be observed. Furthermore, soil CO2 production and efflux did not increase significantly upon exposure of previously darkened macrocosms to light. Under constant temperature and fluctuating light conditions, we observed a dampened diel pattern of Rs, which did not match diurnal solar cycles. A detailed residual analysis accounting for temporal trends in soil moisture suggested a significant

  1. The economic production lot size model extended to include more than one production rate

    DEFF Research Database (Denmark)

    Larsen, Christian

    2005-01-01

    production rates should be chosen in the interval between the demand rate and the production rate which minimizes unit production costs, and should be used in an increasing order. Then, given the production rates, we derive closed-form expressions for all optimal runtimes as well as the minimum average cost....... This analysis reveals that it is the size of the setup cost that determines the need for being able to use several production rates. We also show how to derive a near-optimal solution of the general problem....

  2. Soil-Web: An online soil survey for California, Arizona, and Nevada

    Science.gov (United States)

    Beaudette, D. E.; O'Geen, A. T.

    2009-10-01

    Digital soil survey products represent one of the largest and most comprehensive inventories of soils information currently available. The complex structure of these databases, intensive use of codes and scientific jargon make it difficult for