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Sample records for aerobic sandy soil

  1. Biofuel components change the ecology of bacterial volatile petroleum hydrocarbon degradation in aerobic sandy soil.

    PubMed

    Elazhari-Ali, Abdulmagid; Singh, Arvind K; Davenport, Russell J; Head, Ian M; Werner, David

    2013-02-01

    We tested the hypothesis that the biodegradation of volatile petroleum hydrocarbons (VPHs) in aerobic sandy soil is affected by the blending with 10 percent ethanol (E10) or 20 percent biodiesel (B20). When inorganic nutrients were scarce, competition between biofuel and VPH degraders temporarily slowed monoaromatic hydrocarbon degradation. Ethanol had a bigger impact than biodiesel, reflecting the relative ease of ethanol compared to methyl ester biodegradation. Denaturing gradient gel electrophoresis (DGGE) of bacterial 16S rRNA genes revealed that each fuel mixture selected for a distinct bacterial community, each dominated by Pseudomonas spp. Despite lasting impacts on soil bacterial ecology, the overall effects on VHP biodegradation were minor, and average biomass yields were comparable between fuel types, ranging from 0.40 ± 0.16 to 0.51 ± 0.22 g of biomass carbon per gram of fuel carbon degraded. Inorganic nutrient availability had a greater impact on petroleum hydrocarbon biodegradation than fuel composition. PMID:23202642

  2. Biofuel components change the ecology of bacterial volatile petroleum hydrocarbon degradation in aerobic sandy soil.

    PubMed

    Elazhari-Ali, Abdulmagid; Singh, Arvind K; Davenport, Russell J; Head, Ian M; Werner, David

    2013-02-01

    We tested the hypothesis that the biodegradation of volatile petroleum hydrocarbons (VPHs) in aerobic sandy soil is affected by the blending with 10 percent ethanol (E10) or 20 percent biodiesel (B20). When inorganic nutrients were scarce, competition between biofuel and VPH degraders temporarily slowed monoaromatic hydrocarbon degradation. Ethanol had a bigger impact than biodiesel, reflecting the relative ease of ethanol compared to methyl ester biodegradation. Denaturing gradient gel electrophoresis (DGGE) of bacterial 16S rRNA genes revealed that each fuel mixture selected for a distinct bacterial community, each dominated by Pseudomonas spp. Despite lasting impacts on soil bacterial ecology, the overall effects on VHP biodegradation were minor, and average biomass yields were comparable between fuel types, ranging from 0.40 ± 0.16 to 0.51 ± 0.22 g of biomass carbon per gram of fuel carbon degraded. Inorganic nutrient availability had a greater impact on petroleum hydrocarbon biodegradation than fuel composition.

  3. Biochar increases plant available water in a sandy soil under an aerobic rice cropping system

    NASA Astrophysics Data System (ADS)

    de Melo Carvalho, M. T.; de Holanda Nunes Maia, A.; Madari, B. E.; Bastiaans, L.; van Oort, P. A. J.; Heinemann, A. B.; Soler da Silva, M. A.; Petter, F. A.; Meinke, H.

    2014-03-01

    The main objective of this study was to assess the impact of biochar rate (0, 8, 16 and 32 t ha-1) on the water retention capacity (WRC) of a sandy Dystric Plinthosol. The applied biochar was a by-product of slow pyrolysis (∼450 °C) of eucalyptus wood, milled to pass through a 2000 μm sieve that resulted in a material with an intrinsic porosity ≤10 μm and a specific surface area of ∼3.2 m2 g-1. The biochar was incorporated into the top 15 cm of the soil under an aerobic rice system. Our study focused on both the effects on WRC and rice yields at 2 and 3 years after application. Undisturbed soil samples were collected from 16 plots in two soil layers (5-10 and 15-20 cm). Soil water retention curves were modelled using a nonlinear mixed model which appropriately accounts for uncertainties inherent of spatial variability and repeated measurements taken within a specific soil sample. We found an increase in plant available water in the upper soil layer proportional to the rate of biochar, with about 0.8% for each t ha-1 of biochar amendment at 2 and 3 years after application. The impact of biochar on soil WRC was most likely related to an increase in overall porosity of the sandy soil, which was evident from an increase in saturated soil moisture and macro porosity with 0.5% and 1.6% for each t ha-1 of biochar applied, respectively. The increment in soil WRC did not translate into an increase in rice yield, essentially because in both seasons the amount of rainfall during critical period for rice production exceeded 650 mm. The use of biochar as a soil amendment can be a worthy strategy to guarantee yield stability under water limited conditions. Our findings raise the importance of assessing the feasibility of very high application rates of biochar and the inclusion of a detailed analysis of its physical and chemical properties as part of future investigations.

  4. Biochar increases plant-available water in a sandy loam soil under an aerobic rice crop system

    NASA Astrophysics Data System (ADS)

    de Melo Carvalho, M. T.; de Holanda Nunes Maia, A.; Madari, B. E.; Bastiaans, L.; van Oort, P. A. J.; Heinemann, A. B.; Soler da Silva, M. A.; Petter, F. A.; Marimon, B. H., Jr.; Meinke, H.

    2014-09-01

    The main objective of this study was to assess the impact of biochar rate (0, 8, 16 and 32 Mg ha-1) on the water retention capacity (WRC) of a sandy loam Dystric Plinthosol. The applied biochar was a by-product of slow pyrolysis (∼450 °C) of eucalyptus wood, milled to pass through a 2000 μm sieve that resulted in a material with an intrinsic porosity ≤10 μm and a specific surface area of ∼3.2 m2 g-1. The biochar was incorporated into the top 15 cm of the soil under an aerobic rice system. Our study focused on both the effects on WRC and rice yields 2 and 3 years after its application. Undisturbed soil samples were collected from 16 plots in two soil layers (5-10 and 15-20 cm). Soil water retention curves were modelled using a nonlinear mixed model which appropriately accounts for uncertainties inherent of spatial variability and repeated measurements taken within a specific soil sample. We found an increase in plant-available water in the upper soil layer proportional to the rate of biochar, with about 0.8% for each Mg ha-1 biochar amendment 2 and 3 years after its application. The impact of biochar on soil WRC was most likely related to an effect in overall porosity of the sandy loam soil, which was evident from an increase in saturated soil moisture and macro porosity with 0.5 and 1.6% for each Mg ha-1 of biochar applied, respectively. The increment in soil WRC did not translate into an increase in rice yield, essentially because in both seasons the amount of rainfall during the critical period for rice production exceeded 650 mm. The use of biochar as a soil amendment can be a worthy strategy to guarantee yield stability under short-term water-limited conditions. Our findings raise the importance of assessing the feasibility of very high application rates of biochar and the inclusion of a detailed analysis of its physical and chemical properties as part of future investigations.

  5. ANAEROBIC SOIL DISINFESTATION IN MICROCOSMS OF TWO SANDY SOILS.

    PubMed

    Stremińska, M A; Runia, W T; Termorshuizen, A J; Feil, H; Van Der Wurff, A W G

    2014-01-01

    In recent years, anaerobic soil disinfestation (ASD) has been proposed as an alternative control method of soil-borne plant pathogens. It involves adding a labile carbon source, irrigating the soil to stimulate decomposition of organic material and then covering the soil with air-tight plastic to limit gas exchange. During the ASD process, soil microorganisms switch from aerobic to anaerobic metabolism. As a result, by-products of anaerobic metabolism are released into the soil environment such as various organic acids and gases. These by-products are reported to have a negative effect on survival of soil-borne plant pathogens. However, the efficacy of ASD to reduce soil-borne pathogens in practice may vary significantly. Therefore, we studied the efficacy of the ASD process in two different soils. In addition, it was investigated whether a pre-treatment with an anaerobic bacterial inoculum prior to ASD affected the efficacy of the process. Two sandy soils (dune sand and glacial sand) were inoculated in 2 L soil microcosms. We tested the efficacy of ASD treatment against the potato cyst nematode Globodera pallida. For each soil, three treatments were used: control treatment (no Herbie addition, aerobic incubation), ASD 1 (organic substrate addition, anaerobic incubation) and ASD 2 (organic substrate and anaerobic bacterial inoculum addition, anaerobic incubation). Soil microcosms were incubated in the dark at 20°C for two weeks. We observed that anaerobic soil disinfestation treatments were highly effective against Potato Cyst Nematode (PCN), with pathogen being eradicated totally in all but one ASD treatment (glacial sand ASD2) within two weeks. The relative abundance of Firmicutes (spore-forming bacteria, often fermentative) in total bacteria increased significantly in ASD treated soils. Numbers of these bacteria correlated positively with increased concentrations of acetic and butyric acids in soil water phase in ASD treatments. PMID:26084078

  6. Effects of soil amendment on soil characteristics and maize yield in Horqin Sandy Land

    NASA Astrophysics Data System (ADS)

    Zhou, L.; Liu, J. H.; Zhao, B. P.; Xue, A.; Hao, G. C.

    2016-08-01

    A 4-year experiment was conducted to investigate the inter-annual effects of sandy soil amendment on maize yield, soil water storage and soil enzymatic activities in sandy soil in Northeast China in 2010 to 2014. We applied the sandy soil amendment in different year, and investigated the different effects of sandy soil amendment in 2014. There were six treatments including: (1) no sandy soil amendment application (CK); (2) one year after applying sandy soil amendment (T1); (3) two years after applying sandy soil amendment(T2); (4) three years after applying sandy soil amendment(T3); (5)four years after applying sandy soil amendment(T4); (6) five years after applying sandy soil amendment (T5). T refers to treatment, and the number refers to the year after application of the sandy soil amendment. Comparing with CK, sandy soil amendments improved the soil water storage, soil urease, invertase, and catalase activity in different growth stages and soil layers, the order of soil water storage in all treatments roughly performed: T3 > T5 > T4 > T2 > T1 > CK. the order of soil urease, invertase, and catalase activity in all treatments roughly performed: T5 > T3 > T4 > T2 > T1 > CK. Soil application of sandy soil amendment significantly (p≤⃒0.05) increased the grain yield and biomass yield by 22.75%-41.42% and 29.92%-45.45% respectively, and maize yield gradually increased with the years go by in the following five years. Sandy soil amendment used in poor sandy soil had a positive effect on soil water storage, soil enzymatic activities and maize yield, after five years applied sandy soil amendment (T5) showed the best effects among all the treatments, and deserves further research.

  7. BACTERIOPHAGE TRANSPORT IN SANDY SOIL AND FRACTURED TUFF

    EPA Science Inventory

    Bacteriophage transport was investigated in laboratory column experiments using sandy soil, a controlled field study in a sandy wash, and laboratory experiments using fractured rock. In the soil columns, the phage MS-2 exhibited significant dispersion and was excluded from 35 to ...

  8. Responses of soil fungal community to the sandy grassland restoration in Horqin Sandy Land, northern China.

    PubMed

    Wang, Shao-Kun; Zuo, Xiao-An; Zhao, Xue-Yong; Li, Yu-Qiang; Zhou, Xin; Lv, Peng; Luo, Yong-Qing; Yun, Jian-Ying

    2016-01-01

    Sandy grassland restoration is a vital process including re-structure of soils, restoration of vegetation, and soil functioning in arid and semi-arid regions. Soil fungal community is a complex and critical component of soil functioning and ecological balance due to its roles in organic matter decomposition and nutrient cycling following sandy grassland restoration. In this study, soil fungal community and its relationship with environmental factors were examined along a habitat gradient of sandy grassland restoration: mobile dunes (MD), semi-fixed dunes (SFD), fixed dunes (FD), and grassland (G). It was found that species abundance, richness, and diversity of fungal community increased along with the sandy grassland restoration. The sequences analysis suggested that most of the fungal species (68.4 %) belonged to the phylum of Ascomycota. The three predominant fungal species were Pleospora herbarum, Wickerhamomyces anomalus, and Deconica Montana, accounting for more than one fourth of all the 38 species. Geranomyces variabilis was the subdominant species in MD, Pseudogymnoascus destructans and Mortierella alpine were the subdominant species in SFD, and P. destructans and Fungi incertae sedis were the dominant species in FD and G. The result from redundancy analysis (RDA) and stepwise regression analysis indicated that the vegetation characteristics and soil properties explain a significant proportion of the variation in the fungal community, and aboveground biomass and C:N ratio are the key factors to determine soil fungal community composition during sandy grassland restoration. It was suggested that the restoration of sandy grassland combined with vegetation and soil properties improved the soil fungal diversity. Also, the dominant species was found to be alternative following the restoration of sandy grassland ecosystems.

  9. Acidic sandy soil improvement with biochar - A microcosm study.

    PubMed

    Molnár, Mónika; Vaszita, Emese; Farkas, Éva; Ujaczki, Éva; Fekete-Kertész, Ildikó; Tolner, Mária; Klebercz, Orsolya; Kirchkeszner, Csaba; Gruiz, Katalin; Uzinger, Nikolett; Feigl, Viktória

    2016-09-01

    Biochar produced from a wide range of organic materials by pyrolysis has been reported as a means to improve soil physical properties, fertility and crop productivity. However, there is a lack of studies on the complex effects of biochar both on the degraded sandy soil physico-chemical properties and the soil biota as well as on toxicity, particularly in combined application with fertilizer and compost. A 7-week microcosm experiment was conducted to improve the quality of an acidic sandy soil combining variations in biochar types and amounts, compost and fertilizer application rates. The applied biochars were produced from different feedstocks such as grain husks, paper fibre sludge and wood screenings. The main purpose of the microcosm experiment was to assess the efficiency and applicability of different biochars as soil amendment prior to field trials and to choose the most efficient biochar to improve the fertility, biological activity and physical properties of acidic sandy soils. We complemented the methodology with ecotoxicity assessment to evaluate the possible risks to the soil as habitat for microbes, plants and animals. There was clear evidence of biochar-soil interactions positively affecting both the physico-chemical properties of the tested acidic sandy soil and the soil biota. Our results suggest that the grain husk and the paper fibre sludge biochars applied to the tested soil at 1% and 0.5 w/w% rate mixed with compost, respectively can supply a more liveable habitat for plants and soil living animals than the acidic sandy soil without treatment.

  10. Soil vapor extraction in sandy soils: influence of airflow rate.

    PubMed

    Albergaria, José Tomás; Alvim-Ferraz, Maria da Conceição M; Delerue-Matos, Cristina

    2008-11-01

    Airflow rate is one of the most important parameters for the soil vapor extraction of contaminated sites, due to its direct influence on the mass transfer occurring during the remediation process. This work reports the study of airflow rate influence on soil vapor extractions, performed in sandy soils contaminated with benzene, toluene, ethylbenzene, xylene, trichloroethylene and perchloroethylene. The objectives were: (i) to analyze the influence of airflow rate on the process; (ii) to develop a methodology to predict the remediation time and the remediation efficiency; and (iii) to select the most efficient airflow rate. For dry sandy soils with negligible contents of clay and natural organic matter, containing the contaminants previously cited, it was concluded that: (i) if equilibrium between the pollutants and the different phases present in the soil matrix was reached and if slow diffusion effects did not occur, higher airflow rates exhibited the fastest remediations, (ii) it was possible to predict the remediation time and the efficiency of remediation with errors below 14%; and (iii) the most efficient remediation were reached with airflow rates below 1.2 cm(3)s(-1) standard temperature and pressure conditions.

  11. Switchgrass and pecan biochar amendments to a sandy coastal soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sandy soils of the wet, warm SE Coastal Plain have poor physical characteristics and low carbon contents. To improve soil properties, we added switchgrass (Panicum virgatum) and non-activated pecan (Carya illinoinensis) biochar. Switchgrass was ground to a fine powder and added to soil at rates of 0...

  12. Acidic sandy soil improvement with biochar - A microcosm study.

    PubMed

    Molnár, Mónika; Vaszita, Emese; Farkas, Éva; Ujaczki, Éva; Fekete-Kertész, Ildikó; Tolner, Mária; Klebercz, Orsolya; Kirchkeszner, Csaba; Gruiz, Katalin; Uzinger, Nikolett; Feigl, Viktória

    2016-09-01

    Biochar produced from a wide range of organic materials by pyrolysis has been reported as a means to improve soil physical properties, fertility and crop productivity. However, there is a lack of studies on the complex effects of biochar both on the degraded sandy soil physico-chemical properties and the soil biota as well as on toxicity, particularly in combined application with fertilizer and compost. A 7-week microcosm experiment was conducted to improve the quality of an acidic sandy soil combining variations in biochar types and amounts, compost and fertilizer application rates. The applied biochars were produced from different feedstocks such as grain husks, paper fibre sludge and wood screenings. The main purpose of the microcosm experiment was to assess the efficiency and applicability of different biochars as soil amendment prior to field trials and to choose the most efficient biochar to improve the fertility, biological activity and physical properties of acidic sandy soils. We complemented the methodology with ecotoxicity assessment to evaluate the possible risks to the soil as habitat for microbes, plants and animals. There was clear evidence of biochar-soil interactions positively affecting both the physico-chemical properties of the tested acidic sandy soil and the soil biota. Our results suggest that the grain husk and the paper fibre sludge biochars applied to the tested soil at 1% and 0.5 w/w% rate mixed with compost, respectively can supply a more liveable habitat for plants and soil living animals than the acidic sandy soil without treatment. PMID:26850860

  13. Microfungi diversity isolation from sandy soil of Acapulco touristic beaches

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Microscopic fungi diversity in marine sandy soil habitats is associated with key functions of beach ecosystems. There are few reports on their presence in Mexican beaches. Although standard methods to obtain the fungi from soil samples are established, the aim of this pilot study was to test the pla...

  14. The biogenic emission potential of nitric oxide from sandy soils

    NASA Astrophysics Data System (ADS)

    Yu, J. B.; Meixner, F. X.; Sun, Z. G.; Chen, X. B.; Mamtimin, B.

    2009-04-01

    There are about 160.9 Mha of sandy land in China, about 17.6% of total Chinese area, which mainly distributed in 35°-50° N. The western Songnen Plain, which located in the semi-arid region of Northeastern China, is one of the main sandy soil distribution regions. The changes of land use in sandy soil are accompanied by changes in biogeochemical cycles of nutrients, particularly of the air-surface exchange of trace gases like nitric oxide. Our study, based on results obtained by a laboratory incubation technique, focuses on (a) NO production and consumption in sandy soils from two types of land use as function of soil temperature and soil moisture, and (b) The biogenic emission potential of nitric oxide from sandy soils in semi-arid region. At 25˚C, average NO production (in terms of mass of N) was 0.016,and 0.013 ng kg-1s-1 in sandy soils from soybean land (SL) and man-made forest (MF), re¬spectively. NO consumption rate constant ranged from 0.26×10-6 to 7.28×10-6 m3 kg-1s-1. At 25˚C and under optimum soil moisture conditions for NO production, the NO compensation point mixing ratio was about 266 and 161 ug m-3 (465,and 281 ppb) for soils of SL and MF, respectively. Statistically sound relationships have been observed between NO fluxes and soil moisture (optimum curves). NO fluxes also increased exponentially with soil temperature at any given soil moisture. The optimum soil moisture for which maximum NO flux was observed was independent of soil temperature. The maximum of NO flux potentials for SL and MF soils (at 25°C) were 59.6 and 36.5 ng m-2s-1 at water-filled pore space (%WFPS) of 26 and 24, respectively. The NO flux potential was about 2 times larger for cropland soil than for man-made forest soils, most likely due to fertilizer application to the cropland soils.

  15. FIELD SAMPLING OF RESIDUAL AVIATION GASOLINE IN SANDY SOIL

    EPA Science Inventory

    Two complimentary field sampling methods for the determination of residual aviation gasoline content in the contaminated capillary fringe of a fine, uniform, sandy soil were investigated. The first method featured filed extrusion of core barrels into pint size Mason jars, while ...

  16. Deep Compaction Control of Sandy Soils

    NASA Astrophysics Data System (ADS)

    Bałachowski, Lech; Kurek, Norbert

    2015-02-01

    Vibroflotation, vibratory compaction, micro-blasting or heavy tamping are typical improvement methods for the cohesionless deposits of high thickness. The complex mechanism of deep soil compaction is related to void ratio decrease with grain rearrangements, lateral stress increase, prestressing effect of certain number of load cycles, water pressure dissipation, aging and other effects. Calibration chamber based interpretation of CPTU/DMT can be used to take into account vertical and horizontal stress and void ratio effects. Some examples of interpretation of soundings in pre-treated and compacted sands are given. Some acceptance criteria for compaction control are discussed. The improvement factors are analysed including the normalised approach based on the soil behaviour type index.

  17. Feasibility of toxaphene transport through sandy soil

    SciTech Connect

    Jaquess, A.B.; Winterlin, W.; Peterson, D.

    1989-03-01

    Toxaphene, produced by the chlorination of camphene, is a chlorinated hydrocarbon insecticide that was widely used to control a variety of insects on crops and to control livestock skin parasites. It is known to be a toxic and a highly persistent chemical in soil where its half-life can be in excess of ten years, depending on the environmental conditions. This study was conducted in an attempt to explain a finding in this lab of high concentrations of toxaphene (2600 ppm) in soil sampled at a depth of 1 m. The source of the sample was from a pesticide waste facility in northern California. The paradox of this discovery was that toxaphene, being hydrophobic, has been shown to be restricted in its movement from agricultural applications to a reported maximum of 30 cm, with the bulk of material concentrated in the upper 10 cm. Toxaphene is known to undergo anaerobic degradation that changes its gas chromatography profile. The toxaphene analyzed in this sample had an unweathered profile similar to technical toxaphene, implying that no degradation had occurred. Since a waste disposal facility is faced with abnormally high concentrations of pesticides and formulation components, it was of interest to ascertain if movement in a soil profile was possible when such concentrations prevail in a waste facility.

  18. Mitigation of Liquefaction in Sandy Soils Using Stone Columns

    NASA Astrophysics Data System (ADS)

    Selcuk, Levent; Kayabalı, Kamil

    2010-05-01

    Soil liquefaction is one of the leading causes of earthquake-induced damage to structures. Soil improvement methods provide effective solutions to reduce the risk of soil liquefaction. Thus, soil ground treatments are applied using various techniques. However, except for a few ground treatment methods, they generally require a high cost and a lot of time. Especially in order to prevent the risk of soil liquefaction, stone columns conctructed by vibro-systems (vibro-compaction, vibro-replacement) are one of the traditional geotechnical methods. The construction of stone columns not only enhances the ability of clean sand to drain excess pore water during an earthquake, but also increases the relative density of the soil. Thus, this application prevents the development of the excess pore water pressure in sand during earthquakes and keeps the pore pressure ratio below a certain value. This paper presents the stone column methods used against soil liquefaction in detail. At this stage, (a) the performances of the stone columns were investigated in different spacing and diameters of columns during past earthquakes, (b) recent studies about design and field applications of stone columns were presented, and (c) a new design method considering the relative density of soil and the capacity of drenage of columns were explained in sandy soil. Furthermore, with this new method, earthquake performances of the stone columns constructed at different areas were investigated before the 1989 Loma Prieta and the 1994 Northbridge earthquakes, as case histories of field applications, and design charts were compiled for suitable spacing and diameters of stone columns with consideration to the different sandy soil parameters and earhquake conditions. Key Words: Soil improvement, stone column, excess pore water pressure

  19. Effects of leachate on geotechnical characteristics of sandy clay soil

    NASA Astrophysics Data System (ADS)

    Harun, N. S.; Ali, Z. Rahman; Rahim, A. S.; Lihan, T.; Idris, R. M. W.

    2013-11-01

    Leachate is a hazardous liquid that poses negative impacts if leaks out into environments such as soil and ground water systems. The impact of leachate on the downgraded quality in terms of chemical characteristic is more concern rather than the physical or mechanical aspect. The effect of leachate on mechanical behaviour of contaminated soil is not well established and should be investigated. This paper presents the preliminary results of the effects of leachate on the Atterberg limit, compaction and shear strength of leachate-contaminated soil. The contaminated soil samples were prepared by mixing the leachate at ratiosbetween 0% and 20% leachate contents with soil samples. Base soil used was residual soil originated from granitic rock and classified as sandy clay soil (CS). Its specific gravity ranged between 2.5 and 2.64 with clay minerals of kaolinite, muscovite and quartz. The field strength of the studied soil ranged between 156 and 207 kN/m2. The effects of leachate on the Atterberg limit clearly indicated by the decrease in liquid and plastic limit values with the increase in the leachate content. Compaction tests on leachate-contaminated soil caused the dropped in maximum dry density, ρdry and increased in optimum moisture content, wopt when the amount of leachate was increased between 0% and 20%. The results suggested that leachate contamination capable to modify some geotechnical properties of the studied residual soils.

  20. Remediation of sandy soils using surfactant solutions and foams.

    PubMed

    Couto, Hudson J B; Massarani, Guilio; Biscaia, Evaristo C; Sant'Anna, Geraldo L

    2009-05-30

    Remediation of sandy soils contaminated with diesel oil was investigated in bench-scale experiments. Surfactant solution, regular foams and colloidal gas aphrons were used as remediation fluids. An experimental design technique was used to investigate the effect of relevant process variables on remediation efficiency. Soils prepared with different average particle sizes (0.04-0.12 cm) and contaminated with different diesel oil contents (40-80 g/kg) were used in experiments conducted with remediation fluids. A mathematical model was proposed allowing for the determination of oil removal rate-constant (k(v)) and oil content remaining in the soil after remediation (C(of)) as well as estimation of the percentage of oil removed. Oil removal efficiencies obtained under the central experimental design conditions were 96%, 88% and 35% for aphrons, regular foams and surfactant solutions, respectively. High removal efficiencies were obtained using regular foams and aphrons, demanding small amounts of surfactant.

  1. Electrochemically enhanced oxidation reactions in sandy soil polluted with mercury

    PubMed

    Thoming; Kliem; Ottosen

    2000-10-16

    For remediation of soils contaminated with heavy metals, the electrodialytic remediation (EDR) method is a highly relevant method, see e.g. Hansen et al. (Hansen HK, Ottosen LM, Kliem BK, Villumsen A. Electrodialytic remediation of soils polluted with Cu, Cr, Hg, Pb, and Zn. J Chem Tech Biotechnol 1997;70:67-73). During the process the heavy metals are transferred to the pore water in dissolved form or attached to colloids and move within the applied electric field. The method is found to be useful in many soil types, but has its strength in fine-grained soils. It is exactly in such soils that other remediation methods fail. Four cell experiments were made in order to investigate how relevant the method is for a more sandy soil and if it is suitable for non-ionic heavy metals such as elemental mercury. The duration was 27 days for two of the experiments and two experiments lasted 54 days, and the mercury within the soil was initially 1200-1900 mg kg(-1), of which 84% was elemental Hg. To monitor the process the pseudo-total mercury concentration was distinguished between elemental mercury and non-metallic mercury species by thermodesorption. During the electrodialytic treatment an increase of the content of non-metallic mercury occurred and a corresponding decrease of the content of elemental mercury which indicates a transformation of the latter species into any other non-metallic species. Generally, oxidation of Hg by dissolved oxygen in a solution is kinetically inhibited and thus quite slow. The redistribution of Hg was closely connected to a decrease of soil pH during the experiments. This corresponds very well to the thermodynamic calculations from which it was found that a decrease in the pH of the soil will result in an increase in the oxidation rate of elemental Hg. Results from this investigation show that the electrodialytic remediation method alone is not efficient in situations with sandy soils containing elemental mercury. As a solution for this

  2. Substrate- and nutrient-limited toluene biotransformation in sandy soil

    SciTech Connect

    Allen-King, R.M. . Dept. of Geology); Barker, J.F.; Gillham, R.W. . Waterloo Centre for Groundwater Research); Jensen, B.K. . Environmental Biotechnology Section)

    1994-05-01

    Lab microcosm tests of the rate of toluene biodegradation were performed using soil from the A, B, and C horizons of the unsaturated zone of a sandy field site. Toluene biodegradation was rapid, occurring at a time scale comparable to the rate of sorption in many of the microcosms and demonstrating the potential for bioremediation of these contaminants in unsaturated soil. In the A horizon, with an initial toluene concentration in the solution phase of 4.5 mg/L, degradation was controlled by substrate-limited growth on toluene as the primary substrate. Soil from the B and C horizons initially showed similar behavior with a lower toluene concentrations of about 2.5 mg/L. The maximum utilization rate ([mu][sub max]) for soil from all three depths was 2.0 d[sup [minus]1]. With repeated exposure to moderate to high concentrations of toluene, transformation in the B- and C-horizon soil appeared to be zero order, at a rate of 1.0 to 2.0 [mu]g toluene/g soil/d. In C-horizon soil that had been taken directly from the field, the transformation rate was almost immeasurably slow. Addition of nitrogens as either ammonium or nitrate accelerated the degradation, showing that nitrogen was the most limiting nutrient. The apparent adaptation period observed before rapid toluene removal was fit by a substrate-limited growth model. Greater numbers of toluene-degrading microorganisms were found in soil exposed to toluene than in unexposed soil, supporting biomass growth as the explanation for the adaptation period. The results of enumeration of heterotrophs compared to the numbers of toluene degraders suggested that a small proportion to the total viable microorganisms were responsible for degradation of toluene.

  3. Nitrogen mineralization and nitrate leaching of a sandy soil amended with different organic wastes.

    PubMed

    Burgos, Pilar; Madejón, Engracia; Cabrera, Francisco

    2006-04-01

    Organic wastes can be recycled as a source of plant nutrients, enhancing crop production by improving soil quality. However, the study of the dynamic of soil nutrient, especially the N dynamic, after soil application of any organic material is vital for assessing a correct and effective use of the material, minimizing the losses of nitrate in leachates and avoiding the negative environmental effects that it may cause in groundwater. To estimate the effect of three organic materials, a municipal solid waste compost (MWC), a non-composted paper mill sludge (PS), and an agroforest compost (AC) on the N dynamic of a sandy soil two experiments were carried out: an incubation experiment and a column experiment. The incubation experiment was conducted to estimate the N mineralization rate of the different soil-amendment mixtures. The soil was mixed with the organic amendments at a rate equivalent to 50,000 kg ha(-1) and incubated during 40 weeks at constant moisture content (70% of its water-holding capacity) and temperature (28 degrees C) under aerobic conditions. Organic amendment-soil samples showed an immobilization of N during the first weeks, which was more noticeable and longer in the case of PS-treated soil compared to the other two amendments due to its high C/N ratio. After this immobilization stage, a positive mineralization was observed for all treatment, especially in MWC treated soil. Contemporaneously a 1-year column (19 cm diameter and 60 cm height) experiment was carried out to estimate the nitrate losses from the soil amended with the same organic materials. Amendments were mixed with the top soil (0-15 cm) at a rate equivalent to 50,000 kg ha(-1). The columns were periodically irrigated simulating rainfall in the area of study, receiving in total 415 mm of water, and the water draining was collected during the experimental period and analysed for NO3-N. At the end of the experimental period NO3-N content in soil columns at three depths (0-20, 20-35 and

  4. Nitrogen mineralization and nitrate leaching of a sandy soil amended with different organic wastes.

    PubMed

    Burgos, Pilar; Madejón, Engracia; Cabrera, Francisco

    2006-04-01

    Organic wastes can be recycled as a source of plant nutrients, enhancing crop production by improving soil quality. However, the study of the dynamic of soil nutrient, especially the N dynamic, after soil application of any organic material is vital for assessing a correct and effective use of the material, minimizing the losses of nitrate in leachates and avoiding the negative environmental effects that it may cause in groundwater. To estimate the effect of three organic materials, a municipal solid waste compost (MWC), a non-composted paper mill sludge (PS), and an agroforest compost (AC) on the N dynamic of a sandy soil two experiments were carried out: an incubation experiment and a column experiment. The incubation experiment was conducted to estimate the N mineralization rate of the different soil-amendment mixtures. The soil was mixed with the organic amendments at a rate equivalent to 50,000 kg ha(-1) and incubated during 40 weeks at constant moisture content (70% of its water-holding capacity) and temperature (28 degrees C) under aerobic conditions. Organic amendment-soil samples showed an immobilization of N during the first weeks, which was more noticeable and longer in the case of PS-treated soil compared to the other two amendments due to its high C/N ratio. After this immobilization stage, a positive mineralization was observed for all treatment, especially in MWC treated soil. Contemporaneously a 1-year column (19 cm diameter and 60 cm height) experiment was carried out to estimate the nitrate losses from the soil amended with the same organic materials. Amendments were mixed with the top soil (0-15 cm) at a rate equivalent to 50,000 kg ha(-1). The columns were periodically irrigated simulating rainfall in the area of study, receiving in total 415 mm of water, and the water draining was collected during the experimental period and analysed for NO3-N. At the end of the experimental period NO3-N content in soil columns at three depths (0-20, 20-35 and

  5. Travel of pollution, and purification en route, in sandy soils

    PubMed Central

    Baars, J. K.

    1957-01-01

    The travel of pollution in sandy soils, and the extent to which purification takes place en route, are discussed, with special reference to the possible contamination of ground water—a problem which is of particular importance in the Netherlands, where the water-supply for many of the large towns is drawn from the water underneath the dunes. Specifically, two types of soil pollution are considered: (a) severe pollution of the surface layers with matter concentrated in a small volume of water (e.g., faecal matter from pit privies at camping-sites); and (b) moderate pollution of the surface layers with matter contained in large quantities of water (e.g., organic matter and bacteria in river water used for the artificial recharge of ground water). It is shown that in both these types of pollution the self-purification is sufficient to prevent contamination of the ground water, provided that the soil is very fine and—in the case of the first type—dry and well aerated, and provided that the ground-water level is not too high or the rate of infiltration too great. PMID:13472428

  6. Phosphorus leaching from biosolids-amended sandy soils.

    PubMed

    Elliott, H A; O'Connor, G A; Brinton, S

    2002-01-01

    Increasing emphasis on phosphorus (P)-based nutrient management underscores the need to understand P behavior in soils amended with biosolids and manures. Laboratory and greenhouse column studies characterized P forms and leachability of eight biosolids products, chicken manure (CM), and commercial fertilizer (triple superphosphate, TSP). Bahiagrass (Paspalum notatum Flugge) was grown for 4 mo on two acid, P-deficient Florida sands, representing both moderate (Candler series: hyperthermic, uncoated Typic Quartzipsamments) and very low (Immokalee series: sandy, siliceous, hyperthermic Arenic Alaquods) P-sorbing capacities. Amendments were applied at 56 and 224 kg P(T) ha(-1), simulating P-based and N-based nutrient loadings, respectively. Column leachate P was dominantly inorganic and lower for biosolids P sources than TSP. For Candler soil, only TSP at the high P rate exhibited P leaching statistically greater (alpha = 0.05) than control (soil-only) columns. For the high P rate and low P-sorbing Immokalee soil, TSP and CM leached 21 and 3.0% of applied P, respectively. Leachate P for six biosolids was <1.0% of applied P and not statistically different from controls. Largo biosolids, generated from a biological P removal process, exhibited significantly greater leachate P in both cake and pelletized forms (11 and 2.5% of applied P, respectively) than other biosolids. Biosolids P leaching was correlated to the phosphorus saturation index (PSI = [Pox]/[Al(ox) + Fe(ox)]) based on oxalate extraction of the pre-applied biosolids. For hiosolids with PSI < or = approximately 1.1, no appreciable leaching occurred. Only Largo cake (PSI = 1.4) and pellets (PSI = 1.3) exhibited P leaching losses statistically greater than controls. The biosolids PSI appears useful for identifying biosolids with potential to enrich drainage P when applied to low P-sorbing soils. PMID:11931462

  7. Nutrient Transformations in Soils Under Aerobic and Anaerobic Conditions

    NASA Astrophysics Data System (ADS)

    Owens, P.; Lee, L.

    2003-12-01

    Poultry litter is most commonly land applied as a fertilizer for pastures. Soils vary according to landscape position and the biogeochemistry changes within the soils depending on the landscape position. This research focuses on nutrient speciation in aerobic and anaerobic environments. A 3.4 kg Ha-1 chicken litter application rate was used to determine the speciation of nutrients in these two environments. A 50 g sample of Ruston soil was placed in 250 mL centrifuge tubes and continuously stirred in anaerobic and aerobic environments. The Eh and pH were measured daily and a sample was collected at 0, 3, 7, 14 and 21 days. The Eh decreased from around 600 mV at day 0 to near 100 at day 2; whereas the aerobic sample had a decrease to around 450 mV. The pH increased from 6.5 to 7.0 in the anaerobic soil and from 6.5 to around 8.0 in the aerobic soil. The anaerobic soils had a rapid decrease in NO3- and a sharp increase in NH4+ to around 100 mg NH4+ kg-1 soil at day 7. The aerobic soil had an increase in NH4+ to 70 mg Nh4+ kg-1 soil at day 7 then decrease in NH4+ with a corresponding increase in NO3-. Both the anaerobic and aerobic soil had a rapid decrease in PO42- concentrations and remained low for 21 d.

  8. [Soil condensation water in different habitats in Horqin sandy land: an experimental study].

    PubMed

    Liu, Xin-Ping; He, Yu-Hui; Zhao, Xue-Yong; Li, Yu-Lin; Li, Yu-Qiang; Li, Yan-Qing; Li, Shi-min

    2009-08-01

    Weighing method was adopted to study the formation time and the amount of soil condensation water in four habitats (mobile sandy land, fixed sandy land, farmland, and Mongolian pine forest land) in Horqin Sandy Land in August 2007. The soil condensation water began to form at 20:00-22:00, increased gradually at 22:00-4:00, and began to evaporate after 4:00. In the four habitats, soil condensation water was mainly formed in 0-9 cm layer, and the amount was the greatest in 0-3 cm layer, accounting for 40% of the total. The soil condensation water also formed in 9-30 cm layer, but in very small amount. There was a greater difference in the mean daily amount of soil condensation water in 0-3 cm layer in the four habitats, with the sequence of fixed sandy land > mobile sandy land > farmland > Mongolian pine forest land, which indicated that the habitat with better vegetation condition was not benefit the formation of soil condensation water. The mean daily amount of soil condensation water in 0-30 cm layer was 0.172 mm in fixed sandy land, 0.128 mm in Mongolian pine forest land, 0.120 mm in mobile sandy land, and 0.110 mm in farmland. PMID:19947212

  9. Morphology of Rain Water Channeling in Systematically Varied Model Sandy Soils

    NASA Astrophysics Data System (ADS)

    Wei, Yuli; Cejas, Cesare M.; Barrois, Rémi; Dreyfus, Rémi; Durian, Douglas J.

    2014-10-01

    We visualize the formation of fingered flow in dry model sandy soils under different rain conditions using a quasi-2D experimental setup and systematically determine the impact of the soil grain diameter and surface wetting properties on the water channeling phenomenon. The model sandy soils we use are random closely packed glass beads with varied diameters and surface treatments. For hydrophilic sandy soils, our experiments show that rain water infiltrates a shallow top layer of soil and creates a horizontal water wetting front that grows downward homogeneously until instabilities occur to form fingered flows. For hydrophobic sandy soils, in contrast, we observe that rain water ponds on the top of the soil surface until the hydraulic pressure is strong enough to overcome the capillary repellency of soil and create narrow water channels that penetrate the soil packing. Varying the raindrop impinging speed has little influence on water channel formation. However, varying the rain rate causes significant changes in the water infiltration depth, water channel width, and water channel separation. At a fixed rain condition, we combine the effects of the grain diameter and surface hydrophobicity into a single parameter and determine its influence on the water infiltration depth, water channel width, and water channel separation. We also demonstrate the efficiency of several soil water improvement methods that relate to the rain water channeling phenomenon, including prewetting sandy soils at different levels before rainfall, modifying soil surface flatness, and applying superabsorbent hydrogel particles as soil modifiers.

  10. Modification of sandy soil hydrophysical environment through bagasse additive under laboratory experiment

    NASA Astrophysics Data System (ADS)

    Abd El-Halim, A. A.; Kumlung, Arunsiri

    2015-01-01

    Until now sandy soils can be considered as one roup having common hydrophysical problems. Therefore, a laboratory experiment was conducted to evaluate the influence of bagasse as an amendment to improve hydrophysical properties of sandy soil, through the determination of bulk density, aggregatesize distribution, total porosity, hydraulic conductivity, pore-space structure and water retention. To fulfil this objective, sandy soils were amended with bagasse at the rate of 0, 0.5, 1, 2, 3 and 4% on the dry weight basis. The study results demonstrated that the addition of bagasse to sandy soils in between 3 to 4% on the dry weight basis led to a significant decrease in bulk density, hydraulic conductivity, and rapid-drainable pores, and increase in the total porosity, water-holding pores, fine capillary pores, water retained at field capacity, wilting point, and soil available water as compared with the control treatment

  11. Effects of Pisha sandstone content on solute transport in a sandy soil.

    PubMed

    Zhen, Qing; Zheng, Jiyong; He, Honghua; Han, Fengpeng; Zhang, Xingchang

    2016-02-01

    In sandy soil, water, nutrients and even pollutants are easily leaching to deeper layers. The objective of this study was to assess the effects of Pisha sandstone on soil solute transport in a sandy soil. The miscible displacement technique was used to obtain breakthrough curves (BTCs) of Br(-) as an inert non-adsorbed tracer and Na(+) as an adsorbed tracer. The incorporation of Pisha sandstone into sandy soil was able to prevent the early breakthrough of both tracers by decreasing the saturated hydraulic conductivity compared to the controlled sandy soil column, and the impeding effects increased with Pisha sandstone content. The BTCs of Br(-) were accurately described by both the convection-dispersion equation (CDE) and the two-region model (T-R), and the T-R model fitted the experimental data slightly better than the CDE. The two-site nonequilibrium model (T-S) accurately fit the Na(+) transport data. Pisha sandstone impeded the breakthrough of Na(+) not only by decreasing the saturated hydraulic conductivity but also by increasing the adsorption capacity of the soil. The measured CEC values of Pisha sandstone were up to 11 times larger than those of the sandy soil. The retardation factors (R) determined by the T-S model increased with increasing Pisha sandstone content, and the partition coefficient (K(d)) showed a similar trend to R. According to the results of this study, Pisha sandstone can successfully impede solute transport in a sandy soil column.

  12. Relationships between hydric soil indicators and wetland hydrology for sandy soils in Florida. Final report

    SciTech Connect

    Segal, D.S.; Sprecher, S.W.; Watts, F.C.

    1995-02-01

    Several alternative lists of hydric soil indicators have been proposed for use in delineating jurisdictional wetlands in the sandy landscapes of the southeast coastal plain. Because the issue is so recent, very little quantitative research has been conducted to test the validity of these alternative lists. Presence of various hydric soil indicators from four different hydric soil lists was compared with 3 to 5 years of shallow water well data along 14 wetland transects in peninsular Florida. Lists of indicators recently proposed by the USDA Soil Conservation Service were an improvement to the list of hydric soil indicators currently mandated in the Corps of Engineers 1987 and 1989 Wetlands Delineation Manuals. Wetland hydrology and morphological indicators of sandy hydric soils were compared at 58 sites along 14 transects in Florida. The best correspondence between hydrology and soil morphology was found for accumulation of muck on the soil surface and sulfur smell. Poorest correspondence was found for subsoil mineral horizon features such as organic accretions, thick dark A horizon, wet spodosol, and vertical streaking.

  13. Trade-offs between soil hydrology and plant disease effects after biochar amendment in sandy soil

    NASA Astrophysics Data System (ADS)

    Verheijen, Frank; Silva, Flavio; Amaro, Antonio; Pinto, Gloria; Mesquita, Raquel; Jesus, Claudia; Alves, Artur; Keizer, Jacob

    2015-04-01

    Biochar can affect multiple soil-based ecosystem services to varying extents, leading to trade-offs. Improvements in plant-available water have predominantly been found at high biochar application rates in sandy soils. Reductions in plant diseases after biochar application have been found in various horticultural plants, and trees such as maple and oak, mostly at relatively low biochar application rates. Serious damage to Eucalyptus globulus has been reported since 1999 when frequent and severe defoliation of young trees was observed, and eucalypts are the major tree species in commercial forestry plantations of Portugal, forming an important economic activity. Here we investigated simultaneous effects on plant available water and on disease suppression of eucalypt, in a completely randomised full factorial greenhouse pot experiment, using a range of woody feedstock biochar concentrations in sandy soil. Treatments included plant inoculation with the fungus Neofusicoccum kwambonambiense and cycles of acute drought stress. Preliminary results showed delayed wilting for plants treated with 3-6% biochar, but also increased stem lesion length. These results suggest a trade-off between effects on water availability and disease for Eucalyptus globulus plants in the selected sandy soil amended with this specific biochar, at the selected application rates.

  14. [Population development characteristics of rice crop cultivated on aerobic soil with mulching].

    PubMed

    Sheng, Haijun; Shen, Qirong; Feng, Ke

    2004-01-01

    Field experiments were carried out to study the population development characteristics of rice crop cultivated both on aerobic and waterlogged soil conditions. The results showed that the whole growth duration of rice growing on aerobic soil was one week longer than that on waterlogged soil. Shorter and narrower leaves and smaller LAI of rice population were found on aerobic soil than on waterlogged soil, which resulted in a decreased photosynthesis, smaller amount and lighter weight of rice grains on aerobic soil, compared with those on waterlogged soil. Among the aerobic treatments, more tillers, lower percentage of filled grains and shorter duration of grain forming were found on soils covered with plastic film than on soils covered with semi-decomposed straw or without mulching. The rice grain yield was decreased in the order of waterlogged soil > aerobic soil covered with plastic film > aerobic soil covered with semi-decomposed straw > aerobic soil without mulching.

  15. Effect of increasing biochar application rate on soil hydraulic properties of an artificial sandy soil

    NASA Astrophysics Data System (ADS)

    Lopez, V.; Ghezzehei, T. A.

    2013-12-01

    Biochar, a product of the pyrolysis of biomass, has become an increasingly studied subject of interest as an agricultural soil amendment to address issues of carbon emission, population density, and food scarcity. Biochar has been reported to increase content and retention of nutrients, pH, cation-exchange capacity, vegetative growth, microbial community, and carbon sequestration. A number of studies addressing the usefulness of biochar as a soil amendment have focused on chemical and biological properties, disregarding the effects on soil physical properties of amended soil. Aside from biochar, lime (calcium carbonate) addition to soils has also been utilized in agricultural practices, typically to raise the pH value of acidic soils, increase microbial activity, and enhance soil stability and productivity as a result. Both biochar and lime amendments may be beneficial in increasing the soil physical properties, particularly through the formation of aggregates. In previous studies an increase in soil particle aggregates resulted in higher rates of biological activity, infiltration rates, pore space, and aeration, all of which are a measure of soil quality. While the effectiveness of biochar and lime as soil amendments has been independently documented, their combined effectiveness on soil physical properties is less understood. This study aims to provide a further understanding on the effect of increasing biochar application rate on soil particle aggregation and hydraulic properties of a low reactive pre-limed artificial sandy soil with and without microbial communities. Microbial communities are known to increase soil aggregates by acting as cementing agents. Understanding the impact of biochar addition on soil physical properties will have implications in the development of sustainable agricultural practices, especially in systems undergoing climate stress and intensive agriculture.

  16. Degradation of 1,3-dichloropropene in aerobic soils

    SciTech Connect

    Batzer, F.; Balcer, J.L.; Wolt, J.D.

    1995-12-31

    The degradation of the soil fumigant, 1,3-dichloropropene (1,3-D), was investigated to determine its rate of degradation and the identify of metabolites in aerobic soils. Studies were conducted in the dark at 25{degrees}C with uniformly {sup 14}C-labeled 1,3-D at a concentration of approximately 100 ug/g on three soils: Wahiawa silty clay, Catlin silt loam and Fuquay loamy sand. Aerobic soil half-lives for 1,3-D were 1.8, 11.5 and 52.5 days on the Wahiawa silty clay, Catlin silt loam, and Fuquay loamy sand, respectively. Degradation of 1,3-D resulted in the formation of cis- and trans-3-chloroallyl alcohol, cis- and trans-3-chloroacrylic acid, numerous minor carboxylic acid metabolites, and carbon dioxide. In addition, there was also extensive incorporation of {sup 14}C labeled material into the soil organic matter of both soils.

  17. Rain water transport and storage in a model sandy soil with hydrogel particle additives.

    PubMed

    Wei, Y; Durian, D J

    2014-10-01

    We study rain water infiltration and drainage in a dry model sandy soil with superabsorbent hydrogel particle additives by measuring the mass of retained water for non-ponding rainfall using a self-built 3D laboratory set-up. In the pure model sandy soil, the retained water curve measurements indicate that instead of a stable horizontal wetting front that grows downward uniformly, a narrow fingered flow forms under the top layer of water-saturated soil. This rain water channelization phenomenon not only further reduces the available rain water in the plant root zone, but also affects the efficiency of soil additives, such as superabsorbent hydrogel particles. Our studies show that the shape of the retained water curve for a soil packing with hydrogel particle additives strongly depends on the location and the concentration of the hydrogel particles in the model sandy soil. By carefully choosing the particle size and distribution methods, we may use the swollen hydrogel particles to modify the soil pore structure, to clog or extend the water channels in sandy soils, or to build water reservoirs in the plant root zone.

  18. The Effects of Bentonite on the Physic Chemical Characteristics of Sandy Soils in Algeria

    NASA Astrophysics Data System (ADS)

    Reguieg Yssaad, Houcine; Belkhodja, Moulay

    In the objective to rehabilitate the degradation soils and improve the agricultural product, especially cereals and leguminous plants, in the sandy soils countries, we take an interest in the use of bentonite to ameliorate the physical and chemicals properties of these soils. To value the ecological advantage of this clay in these countries, it is proposed a study of increasing amount effect of bentonite on the physical and chemical characteristics on sandy soils. Results show that the texture of mixture tends from sandy soil under 2.5% of bentonite added to sandy silt soil under 7, 10 and 15% of bentonite. The EC increases with the amount bentonite mixture. pH does not fluctuate from one mixture to the another and tends to the alkalinity of soil; Total CaCO3 raises when the bentonite is added in the mixture but active CaCO3 decreases. The high bentonite amounts (10 and 15%) showed no effect on the total phosphorus. The mixture bentonite at 15% reduces the organic carbon and organic matter, whereas total nitrogen falls down when this mixture is enriched with bentonite. Na+ and Ca++ become higher when bentonite increases its amount; K+ reduces in all treatments then this reduction affects Mg++ only under high mixture bentonite (15%).

  19. [Monitoring of water and salt transport in silt and sandy soil during the leaching process].

    PubMed

    Fu, Teng-Fei; Jia, Yong-Gang; Guo, Lei; Liu, Xiao-Lei

    2012-11-01

    Water and salt transport in soil and its mechanism is the key point of the saline soil research. The dynamic rule of water and transport in soil during the leaching process is the theoretical basis of formation, flush, drainage and improvement of saline soil. In this study, a vertical infiltration experiment was conducted to monitor the variation in the resistivity of silt and sandy soil during the leaching process by the self-designed automatic monitoring device. The experimental results showed that the peaks in the resistivity of the two soils went down and faded away in the course of leaching. It took about 30 minutes for sandy soil to reach the water-salt balance, whereas the silt took about 70 minutes. With the increasing leaching times, the desalination depth remained basically the same, being 35 cm for sandy soil and 10 cm for the silt from the top to bottom of soil column. Therefore, 3 and 7 leaching processes were required respectively for the complete desalination of the soil column. The temporal and spatial resolution of this monitoring device can be adjusted according to the practical demand. This device can not only achieve the remote, in situ and dynamic monitoring data of water and salt transport, but also provide an effective method in monitoring, assessment and early warning of salinization.

  20. SOIL AND HYDROLOGY OF A WET-SANDY CATENA IN EAST-CENTRAL MINNESOTA

    EPA Science Inventory

    Sail properties are strongly related to the retention and movement of water within the soil system. The purposes of this study were to document the near-surface hydrology of a wetland-upland hillslope on a sandy glacial outwash plain in east-central Minnesota and to describe the ...

  1. Effect of soil coarseness on soil base cations and available micronutrients in a semi-arid sandy grassland

    NASA Astrophysics Data System (ADS)

    Lü, Linyou; Wang, Ruzhen; Liu, Heyong; Yin, Jinfei; Xiao, Jiangtao; Wang, Zhengwen; Zhao, Yan; Yu, Guoqing; Han, Xingguo; Jiang, Yong

    2016-04-01

    Soil coarseness is the main process decreasing soil organic matter and threatening the productivity of sandy grasslands. Previous studies demonstrated negative effect of soil coarseness on soil carbon storage, but less is known about how soil base cations (exchangeable Ca, Mg, K, and Na) and available micronutrients (available Fe, Mn, Cu, and Zn) response to soil coarseness. In a semi-arid grassland of Northern China, a field experiment was initiated in 2011 to mimic the effect of soil coarseness on soil base cations and available micronutrients by mixing soil with different mass proportions of sand: 0 % coarse elements (C0), 10 % (C10), 30 % (C30), 50 % (C50), and 70 % (C70). Soil coarseness significantly increased soil pH in three soil depths of 0-10, 10-20 and 20-40 cm with the highest pH values detected in C50 and C70 treatments. Soil fine particles (smaller than 0.25 mm) significantly decreased with the degree of soil coarseness. Exchangeable Ca and Mg concentrations significantly decreased with soil coarseness degree by up to 29.8 % (in C70) and 47.5 % (in C70), respectively, across three soil depths. Soil available Fe, Mn, and Cu significantly decreased with soil coarseness degree by 62.5, 45.4, and 44.4 %, respectively. As affected by soil coarseness, the increase of soil pH, decrease of soil fine particles (including clay), and decline in soil organic matter were the main driving factors for the decrease of exchangeable base cations (except K) and available micronutrients (except Zn) through soil profile. Developed under soil coarseness, the loss and redistribution of base cations and available micronutrients along soil depths might pose a threat to ecosystem productivity of this sandy grassland.

  2. Nitroglycerin degradation mediated by soil organic carbon under aerobic conditions.

    PubMed

    Bordeleau, Geneviève; Martel, Richard; Bamba, Abraham N'Valoua; Blais, Jean-François; Ampleman, Guy; Thiboutot, Sonia

    2014-10-01

    The presence of nitroglycerin (NG) has been reported in shallow soils and pore water of several military training ranges. In this context, NG concentrations can be reduced through various natural attenuation processes, but these have not been thoroughly documented. This study aimed at investigating the role of soil organic matter (SOM) in the natural attenuation of NG, under aerobic conditions typical of shallow soils. The role of SOM in NG degradation has already been documented under anoxic conditions, and was attributed to SOM-mediated electron transfer involving different reducing agents. However, unsaturated soils are usually well-oxygenated, and it was not clear whether SOM could participate in NG degradation under these conditions. Our results from batch- and column-type experiments clearly demonstrate that in presence of dissolved organic matter (DOM) leached from a natural soil, partial NG degradation can be achieved. In presence of particulate organic matter (POM) from the same soil, complete NG degradation was achieved. Furthermore, POM caused rapid sorption of NG, which should result in NG retention in the organic matter-rich shallow horizons of the soil profile, thus promoting degradation. Based on degradation products, the reaction pathway appears to be reductive, in spite of the aerobic conditions. The relatively rapid reaction rates suggest that this process could significantly participate in the natural attenuation of NG, both on military training ranges and in contaminated soil at production facilities.

  3. Temporal stability of electrical conductivity in a sandy soil

    NASA Astrophysics Data System (ADS)

    Pedrera-Parrilla, Aura; Brevik, Eric C.; Giráldez, Juan V.; Vanderlinden, Karl

    2016-07-01

    Understanding of soil spatial variability is needed to delimit areas for precision agriculture. Electromagnetic induction sensors which measure the soil apparent electrical conductivity reflect soil spatial variability. The objectives of this work were to see if a temporally stable component could be found in electrical conductivity, and to see if temporal stability information acquired from several electrical conductivity surveys could be used to better interpret the results of concurrent surveys of electrical conductivity and soil water content. The experimental work was performed in a commercial rainfed olive grove of 6.7 ha in the `La Manga' catchment in SW Spain. Several soil surveys provided gravimetric soil water content and electrical conductivity data. Soil electrical conductivity values were used to spatially delimit three areas in the grove, based on the first principal component, which represented the time-stable dominant spatial electrical conductivity pattern and explained 86% of the total electrical conductivity variance. Significant differences in clay, stone and soil water contents were detected between the three areas. Relationships between electrical conductivity and soil water content were modelled with an exponential model. Parameters from the model showed a strong effect of the first principal component on the relationship between soil water content and electrical conductivity. Overall temporal stability of electrical conductivity reflects soil properties and manifests itself in spatial patterns of soil water content.

  4. Biochar and Mill Ash Use as Soil Amendments to Grow Sugarcane in Sandy Soils of South Florida

    NASA Astrophysics Data System (ADS)

    Alvarez-Campos, O.; Lang, T. A.; Bhadha, J. H.; McCray, M.; Gao, B.; Glaz, B.; Daroub, S. H.

    2015-12-01

    The use of agricultural and urban organic residues as amendments provides an option to improve sugarcane production in sandy soils located northwest of the Everglades Agricultural Area, while reducing waste. This study was conducted to determine the effect of mill ash and three biochars on sugarcane yield and sandy soil properties. Mill ash and biochars produced from hardwood yard waste (HY), barn shavings with horse manure (HM), and rice hulls (RH) were incorporated at 1% and 2% (by weight) to sandy soils in a lysimeter experiment. A control without amendment and an often-used commercial practice of mill ash applied at 6% (AS6) were also included. Results showed that RH2 and AS6 produced greater biomass and sucrose yield compared with the control. According to critical nutrient level analysis, RH and AS amendments also resulted in the highest silicon content, which had a positive correlation with increasing sugarcane yield. In addition, RH2 and AS6 increased total phosphorus, Mehlich-3 phosphorus, and cation exchange capacity (CEC) compared with the control. While CEC remained constant with AS2 and AS6 applications, CEC significantly increased over time with RH2. Moreover, higher amendment applications increased soil organic matter compared with the control and did not decrease over time, which suggests a positive influence for long term carbon sustainability and nutrient cycling in sandy soils. Overall, RH2 and AS6 have the most potential to be used as amendments in sandy soils of South Florida due to their positive effects on soil properties, which improved sugarcane yield. However, no negative consequences were found with the application of any other amendment in terms of sugarcane growth and soil quality. Future research should focus on the use of RH and AS amendments on long-term field-scale studies, and the economic feasibility of a single year application on plant and ratoon cane yields.

  5. Metal redistribution by surface casting of four earthworm species in sandy and loamy clay soils.

    PubMed

    Zorn, Mathilde I; van Gestel, Cornelis A M; Eijsackers, Herman J P

    2008-12-01

    Bioturbation of metal contaminated soils contributes considerably to redistribution and surfacing of contaminated soil from deeper layers. To experimentally measure the contribution of Allolobophora chlorotica, Aporrectodea caliginosa, Lumbricus rubellus and L. terrestris to soil surface casting, a time-course experiment was performed under laboratory conditions. Earthworms were incubated in perspex columns filled with sandy soil (2% organic matter, 2.9% clay) or loamy clay soil (15% organic matter, 20% clay), and surface casts were collected after up to 80 days. On the sandy soil, A. caliginosa and L. rubellus brought approximately 7.1-16 g dry wt. casts/g fresh wt. earthworm to the surface, which is significantly more than A. chlorotica and L. terrestris (2.5-5.0 g dry wt./g fresh wt.). A. caliginosa was the only species that produced significantly more surface casts in the sandy soil than in the loamy clay soil. In the loamy clay soil, no differences in biomass-corrected casting rates were found among the species. Surface casting rates tended to decrease after 20 days. Considering the densities of the different species in a Dutch floodplain area Afferdensche and Deestsche Waarden, surface cast production is estimated to amount to 2.0 kg dry soil/m2 after 80 days, which could be extrapolated to 2.7-9.1 kg/m2 per year. These amounts correspond to a surface deposition of a layer of approximately 1.9-6.5 mm/year, which is of the same order or even slightly higher than the sedimentation rate and much higher than the amount of soil brought to the soil surface by bioturbating small mammals. PMID:18771792

  6. Nitrogen availability and indirect measurements of greenhouse gas emissions from aerobic and anaerobic biowaste digestates applied to agricultural soils.

    PubMed

    Rigby, H; Smith, S R

    2013-12-01

    Recycling biowaste digestates on agricultural land diverts biodegradable waste from landfill disposal and represents a sustainable source of nutrients and organic matter (OM) to improve soil for crop production. However, the dynamics of nitrogen (N) release from these organic N sources must be determined to optimise their fertiliser value and management. This laboratory incubation experiment examined the effects of digestate type (aerobic and anaerobic), waste type (industrial, agricultural and municipal solid waste or sewage sludge) and soil type (sandy loam, sandy silt loam and silty clay) on N availability in digestate-amended soils and also quantified the extent and significance of the immobilisation of N within the soil microbial biomass, as a possible regulatory mechanism of N release. The digestate types examined included: dewatered, anaerobically digested biosolids (DMAD); dewatered, anaerobic mesophilic digestate from the organic fraction of municipal solid waste (DMADMSW); liquid, anaerobic co-digestate of food and animal slurry (LcoMAD) and liquid, thermophilic aerobic digestate of food waste (LTAD). Ammonium chloride (NH4Cl) was included as a reference treatment for mineral N. After 48 days, the final, maximum net recoveries of mineral N relative to the total N (TN) addition in the different digestates and unamended control treatments were in the decreasing order: LcoMAD, 68%; LTAD, 37%, DMAD, 20%; and DMADMSW, 11%. A transient increase in microbial biomass N (MBN) was observed with LTAD application, indicating greater microbial activity in amended soil and reflecting the lower stability of this OM source, compared to the other, anaerobic digestate types, which showed no consistent effects on MBN compared to the control. Thus, the overall net release of digestate N in different soil types was not regulated by N transfer into the soil microbial biomass, but was determined primarily by digestate properties and the capacity of the soil type to process and

  7. Plant functional diversity enhances associations of soil fungal diversity with vegetation and soil in the restoration of semiarid sandy grassland.

    PubMed

    Zuo, Xiaoan; Wang, Shaokun; Lv, Peng; Zhou, Xin; Zhao, Xueyong; Zhang, Tonghui; Zhang, Jing

    2016-01-01

    The trait-based approach shows that plant functional diversity strongly affects ecosystem properties. However, few empirical studies show the relationship between soil fungal diversity and plant functional diversity in natural ecosystems. We investigated soil fungal diversity along a restoration gradient of sandy grassland (mobile dune, semifixed dune, fixed dune, and grassland) in Horqin Sand Land, northern China, using the denaturing gradient gel electrophoresis of 18S rRNA and gene sequencing. We also examined associations of soil fungal diversity with plant functional diversity reflected by the dominant species' traits in community (community-weighted mean, CWM) and the dispersion of functional trait values (FD is). We further used the structure equation model (SEM) to evaluate how plant richness, biomass, functional diversity, and soil properties affect soil fungal diversity in sandy grassland restoration. Soil fungal richness in mobile dune and semifixed dune was markedly lower than those of fixed dune and grassland (P < 0.05). Soil fungal richness was positively associated with plant richness, biomass, CWM plant height, and soil gradient aggregated from the principal component analysis, but SEM results showed that plant richness and CWM plant height determined by soil properties were the main factors exerting direct effects. Soil gradient increased fungal richness through indirect effect on vegetation rather than direct effect. The negative indirect effect of FDis on soil fungal richness was through its effect on plant biomass. Our final SEM model based on plant functional diversity explained nearly 70% variances of soil fungal richness. Strong association of soil fungal richness with the dominant species in the community supported the mass ratio hypothesis. Our results clearly highlight the role of plant functional diversity in enhancing associations of soil fungal diversity with community structure and soil properties in sandy grassland ecosystems.

  8. Regional scale assessment of soil predictors of groundwater phosphate (P) levels in acidic sandy agricultural soils

    NASA Astrophysics Data System (ADS)

    Mabilde, Lisa

    2016-04-01

    Possible factors affecting the leaching of P to the groundwater in the Belgian sandy area are examined via regression analysis. The main objective is to investigate the dependency of phreatic groundwater phosphate concentrations (Flemish VMM monitoring net, monitoring period 2010-2013) on soil phosphate saturation degree (PSD) (1994-1997 mapping for Flemish Land Agency) (n = 1032). Additionally explored parameters include: depth distributions of Fe- and Al-oxides, sorbed P and phosphate sorption capacity (PSC) and soil pH. Interpolated data of these soil parameters in 3 depth layers (0-30, 30-60, 60-90 cm) were generated by ordinary kriging. Secondly, we assessed the significance of other edaphic factors potentially controlling the groundwater P: topsoil organic carbon content (OC %), soil clay content and fluctuation of the groundwater table. Overall, the mean PSD halved with each 30 cm depth layer (56 > 24 > 13 %) and was correlated to groundwater PO43‑ level. The statistical significance of the correlation with groundwater PO43‑ concentrations increased with depth layer. The poor correlation (R2 = 0.01) between PSD and groundwater phosphate concentration indicates that many factors, other than soil P status, control the transport of P from soil solution to the groundwater in Belgian sandy soils. A significant (P<0.01) positive non-linear relationship was found between groundwater PO43‑concentration and pHKCl in all three studied depth layers, again increasingly with depth. Within the pH range of the 30-60 cm layer (pHKCl 4.0-5.7) PO4‑ solubility should increase with pH. Elevated soil OC levels surprisingly co-occurred with low groundwater PO43‑ concentrations (r = -0.18, P<0.01, n = 191). Groundwater PO43‑ was furthermore significantly and positively correlated to clay % in both the 0-15 cm (r = 0.15, τ = 0.25, P<0.01, n = 1032) and 60-90 cm (r = 0.13, τ = 0.20, P<0.01, n = 1032) depth increments. These positive correlations were unexpected and

  9. Regional scale assessment of soil predictors of groundwater phosphate (P) levels in acidic sandy agricultural soils

    NASA Astrophysics Data System (ADS)

    Mabilde, Lisa

    2016-04-01

    Possible factors affecting the leaching of P to the groundwater in the Belgian sandy area are examined via regression analysis. The main objective is to investigate the dependency of phreatic groundwater phosphate concentrations (Flemish VMM monitoring net, monitoring period 2010-2013) on soil phosphate saturation degree (PSD) (1994-1997 mapping for Flemish Land Agency) (n = 1032). Additionally explored parameters include: depth distributions of Fe- and Al-oxides, sorbed P and phosphate sorption capacity (PSC) and soil pH. Interpolated data of these soil parameters in 3 depth layers (0-30, 30-60, 60-90 cm) were generated by ordinary kriging. Secondly, we assessed the significance of other edaphic factors potentially controlling the groundwater P: topsoil organic carbon content (OC %), soil clay content and fluctuation of the groundwater table. Overall, the mean PSD halved with each 30 cm depth layer (56 > 24 > 13 %) and was correlated to groundwater PO43- level. The statistical significance of the correlation with groundwater PO43- concentrations increased with depth layer. The poor correlation (R2 = 0.01) between PSD and groundwater phosphate concentration indicates that many factors, other than soil P status, control the transport of P from soil solution to the groundwater in Belgian sandy soils. A significant (P<0.01) positive non-linear relationship was found between groundwater PO43-concentration and pHKCl in all three studied depth layers, again increasingly with depth. Within the pH range of the 30-60 cm layer (pHKCl 4.0-5.7) PO4- solubility should increase with pH. Elevated soil OC levels surprisingly co-occurred with low groundwater PO43- concentrations (r = -0.18, P<0.01, n = 191). Groundwater PO43- was furthermore significantly and positively correlated to clay % in both the 0-15 cm (r = 0.15, τ = 0.25, P<0.01, n = 1032) and 60-90 cm (r = 0.13, τ = 0.20, P<0.01, n = 1032) depth increments. These positive correlations were unexpected and could be

  10. Use of dolomite phosphate rock (DPR) fertilizers to reduce phosphorus leaching from sandy soil.

    PubMed

    Chen, G C; He, Z L; Stoffella, P J; Yang, X E; Yu, S; Calvert, D

    2006-01-01

    There is increasing concern over P leaching from sandy soils applied with water-soluble P fertilizers. Laboratory column leaching experiments were conducted to evaluate P leaching from a typical acidic sandy soil in Florida amended with DPR fertilizers developed from dolomite phosphate rock (DPR) and N-Viro soil. Ten leaching events were carried out at an interval of 7 days, with a total leaching volume of 1,183 mm equivalent to the mean annual rainfall of this region during the period of 2001-2003. Leachates were collected and analyzed for total P and inorganic P. Phosphorus in the leachate was dominantly reactive, accounting for 67.7-99.9% of total P leached. Phosphorus leaching loss mainly occurred in the first three leaching events, accounting for 62.0-98.8% of the total P leached over the whole period. The percentage of P leached (in the total P added) from the soil amended with water-soluble P fertilizer was higher than those receiving the DPR fertilizers. The former was up to 96.6%, whereas the latter ranged from 0.3% to 3.8%. These results indicate that the use of N-Viro-based DPR fertilizers can reduce P leaching from sandy soils.

  11. Changes in physical properties of sandy soil after long-term compost treatment

    NASA Astrophysics Data System (ADS)

    Aranyos, József Tibor; Tomócsik, Attila; Makádi, Marianna; Mészáros, József; Blaskó, Lajos

    2016-07-01

    Studying the long-term effect of composted sewage sludge application on chemical, physical and biological properties of soil, an experiment was established in 2003 at the Research Institute of Nyíregyháza in Hungary. The applied compost was prepared from sewage sludge (40%), straw (25%), bentonite (5%) and rhyolite (30%). The compost was ploughed into the 0-25 cm soil layer every 3rd year in the following amounts: 0, 9, 18 and 27 Mg ha-1 of dry matter. As expected, the compost application improved the structure of sandy soil, which is related with an increase in the organic matter content of soil. The infiltration into soil was improved significantly, reducing the water erosion under simulated high intensity rainfall. The soil compaction level was reduced in the first year after compost re-treatment. In accordance with the decrease in bulk density, the air permeability of soil increased tendentially. However, in the second year the positive effects of compost application were observed only in the plots treated with the highest compost dose because of quick degradation of the organic matter. According to the results, the sewage sludge compost seems to be an effective soil improving material for acidic sandy soils, but the beneficial effect of application lasts only for two years.

  12. Phosphorus leaching from a sandy soil in the presence of modified and un-modified adsorbents.

    PubMed

    Moharami, Somayeh; Jalali, Mohsen

    2014-10-01

    Phosphorus (P) leaching from a sandy soil was investigated in the presence of modified and unmodified clay minerals and nanoparticles (NPs). Compared with control soil, amended soil with NPs had the highest percentage of P retention than amended soil with clay minerals. Among the adsorbents used, the highest percentage of P retention was produced by Al₂O₃-chitosan while the lowest percentage of P retention was by zeolite. Data measured for P leaching after using adsorbents were used to predict P leaching using transport model. PHREEQC model was able to model P leaching from control and amended soil. After leaching, P values in control and amended soil were fractionated by a sequential extraction procedure. Concentration of P in Ca-bound fraction (HCl-P) after application of modified and unmodified clay minerals and NPs (except TiO₂ and Al₂O₃) increased and decreased, respectively. Saturation indices (SIs) and P speciation were assessed using the Visual MINTEQ version 2.3 program. According to the SIs, leaching P from control and amended soil with different adsorbent was controlled by dissolution of hydroxyapatite. The results indicated that used adsorbents can reduce P leaching from the sandy soil. Thus, retention of P by amended soil reduced a risk in terms of groundwater contamination with P.

  13. [Soil microbes functional diversity in sand-fixing Caragana microphylla communities in Horqin Sandy Land].

    PubMed

    Cao, Cheng-you; Yag, Jin-dong; Han, Xiao-shu; Zhang, Ying

    2011-09-01

    Aimed to understand the soil microbes functional diversity in sand-fixing Caragana microphylla communities in Horqin Sandy Land, the soil microbial carbon sources metabolism diversity in 9-, 16-, and 26-yr-old C. microphylla plantations, natural C. microphylla community, and mov-ture, the average well color development (AWCD) and the capabilities of soil microbes in metabo-lizing carboxylic acids, carbohydrates, polymers, amino acids, amines, and aromatics were obvi-ously higher in moving sand dune than in the plantations. The carbon source types metabolized by soil microbes increased with the increasing age of the plantations, and the carbon source metabolic pattern of the soil microbes in 26-yr-old C. microphylla plantation was similar to that in natural C. microphylla community. The functional diversity and evenness index of soil microbes decreased after the establishment of C. microphylla on moving sand dune, whereas the functional diversity of soil microbes increased with increasing age of C. microphylla plantation.

  14. Sorption-desorption of indaziflam and its three metabolites in sandy soils.

    PubMed

    Trigo, Carmen; Koskinen, William C; Kookana, Rai S

    2014-01-01

    Indaziflam is a relatively new herbicide for which sorption-desorption information is lacking, and nothing is available on its metabolites. Information is needed on the multiple soil and pesticide characteristics known to influence these processes. For four soils, the order of sorption was indaziflam (N-[1R,2S)-2,3-dihydro-2,6-dimethyl-1H-inden-1-yl]-6-[(1R)-1-fluoroethyl]-1,3,5-triazine-2,4-diamine) (sandy clay loam: Kf = 5.9, 1/nf = 0.7, Kfoc = 447; sandy loam: Kf = 3.9, 1/nf = 0.9, Kfoc = 276) > triazine indanone metabolite (N-[(1R,2S)-2,3-dihydro-2,6-dimethyl-3-oxo-1H-inden-1-yl]-6-[(1R)-1-fluoroethyl]-1,3,5-triazine-2,4-diamine) (sandy clay loam: Kf = 2.1, 1/nf = 0.8, Kfoc = 177; sandy loam: Kf = 1.7, 1/nf = 0.9, Kfoc = 118) > fluoroethyldiaminotriazine metabolite (6-[(1R-1-Fluoroethyl]-1,3,5-triazine-2,4-diamine) (sandy clay loam: Kf = 0.3, 1/nf = 0.9, Kfoc = 28; sandy loam: Kf = 0.3, 1/nf = 0.9, Kfoc = 22) = indaziflam carboxylic acid metabolite (2S,3R)-3-[[4-amino-6-[(1R)-1-fluoroethyl]-1,3,5-triazin-2-yl]amino]-2,3-dihydro-2-methyl-1H-indene-5-carboxylic acid) (sandy clay loam: Kf = 0.3, 1/nf = 0.9, Kfoc = 22; sandy loam: Kf = 0.5, 1/nf = 0.8, Kfoc = 32). The metabolites being more polar than the parent compound showed lower sorption. Desorption was hysteretic for indaziflam and triazine indanone metabolite, but not for the other two metabolites. Unsaturated transient flow Kd's were lower than batch Kd's for indaziflam, but similar for fluoroethyldiaminotriazine metabolite. Batch Kd's would overpredict potential offsite transport if desorption hysteresis is not taken into account.

  15. Topographical inversion of sandy soils due to local conditions in Northern Poland

    NASA Astrophysics Data System (ADS)

    Jankowski, Michał; Przewoźna, Bogusława; Bednarek, Renata

    2011-12-01

    The investigations carried out in the slope zone of two sandy glaciofluvial terraces in the Toruń Basin (Northern Poland, Central Europe) have shown the occurrence of an inverse slope-sequence of soils. Ground water-affected Gleyic soils (Gleysols) are developed on the surface of the higher terrace and automorphic Rusty Soils (Brunic Arenosols) occupy the lower terrace. The additional element of the sequence unusual for the subboreal zone where the studies take place is the appearance of red colored Ochre Soils (Rubic Arenosols) which are distinctly enriched with iron. The aim of this study is to explain the causes of such distribution of soils. The results show that the difference in stratigraphy of both terraces is the reason for the described phenomena. The lower terrace—of an erosional-accumulative type—is built of deep, permeable glaciofluvial sands. At the higher one, having an erosional character, sandy deposits are underlain with fine-grained lake deposits at a relatively shallow depth. Thus, ground water is retained there leading to the formation of Gleyic soils, but sinks in the deep sands of the lower terrace, where Rusty soils appear. The genesis of Ochre soils should be interpreted as the result of iron oxidation in the transitional zone between the two terraces.

  16. Experimental study and modelling of zinc and lead migration in sandy soils due to stormwater infiltration.

    PubMed

    Marcos, L; Legret, M; Raimbault, G; Le Cloirec, P

    2002-01-01

    Heavy metals emitted by road traffic are contaminants of roadside soils and can potentially migrate through the soils down to groundwater during runoff water infiltration. Stormwater management requires a better understanding of the mechanisms involved in the transport and particularly chemical interactions between heavy metals and the solid matrix. Experiments with open dynamic systems and modelling with a mixing-cells-in-series model have been performed to identify the main reactions which govern the migration of zinc and lead in sandy soils. Binary and ternary exchange experiments have been performed and a numerical modelling was proposed to describe zinc and lead mobility in column experiments.

  17. Evaporation of explosively disseminated liquid drops on a sandy soil surface

    SciTech Connect

    Mellsen, S.B.

    1995-12-31

    As methyl salicylate (MS) is often used as a field simulant for chemical agents, knowledge of its evaporative characteristics is therefore necessary. A series of field trials using a chemical simulant was conducted on sandy soil in the Experimental Proving Ground of the Defence Research Establishment Suffield, located near Medicine Hat, Alberta, Canada. Seven trials were conducted with methyl salicylate thickened to a zero shear viscosity of six poise. Explosive dissemination was used to provide liquid drops. The measured vapor recovery rate was accurately predicted by means of a previously developed mathematical model, by which the effect of varying wind speed, ground temperature and drop sizes are accounted for. The results of these trials are compared to those of similar trials conducted on prairie grassland. The shapes of the vapor recovery versus time curves are similar, but the time scale is longer for evaporation from sandy soil.

  18. Distribution of transformed organic matter in structural units of loamy sandy soddy-podzolic soil

    NASA Astrophysics Data System (ADS)

    Kogut, B. M.; Yashin, M. A.; Semenov, V. M.; Avdeeva, T. N.; Markina, L. G.; Lukin, S. M.; Tarasov, S. I.

    2016-01-01

    The effect of land use types and fertilizing systems on the structural and aggregate composition of loamy sandy soddy-podzolic soil and the quantitative parameters of soil organic matter has been studied. The contribution of soil aggregates 2-1 mm in size to the total Corg reserve in the humus horizon is higher than the contributions of other aggregates by 1.3-4.2 times. Reliable correlations have been revealed between the contents of total (Corg), labile (Clab), and active (C0) organic matter in the soil. The proportion of C0 is 44-70% of Clab extractable by neutral sodium pyrophosphate solution. The contributions of each of the 2-1, 0.5-0.25, and <0.25 mm fractions to the total C0 reserve are 14-21%; the contributions of each of the other fractions are 4-12%. The chemically labile and biologically active components of humic substances reflect the quality changes of soil organic matter under agrogenic impacts. A conceptual scheme has been proposed for the subdivision of soil organic matter into the active, slow (intermediate), and passive pools. In the humus horizon of loamy sandy soddy-podzolic soil, the active, slow, and passive pools contain 6-11, 34-65, and 26-94% of the total Corg, respectively.

  19. Fine dust emissions in sandy and silty agricultural soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dust emissions from strong winds are common in arid and semi-arid regions and occur under both natural and managed land systems. A portable field wind tunnel has been developed to allow measurements of dust emissions from soil surfaces to test the premise that dust concentrations are highly correlat...

  20. Process-based reconstruction of sedimentary rocks, sandy soils and soil aggregates

    NASA Astrophysics Data System (ADS)

    Vasilyev, Roman; Gerke, Kirill; Čapek, Pavel; Karsanina, Marina; Korost, Dmitry

    2013-04-01

    There are three main approaches to model and reconstruct (using 2D cut(s), grain size distribution or some other limited information/properties) porous media: 1) statistical methods (correlation functions and simulated annealing, multi-point statistics, entropy methods), 2) sequential methods (sphere or other shapes granular packs), and 3) morphological methods. Each method has its own advantages and shortcomings, so there is no readily available solution and methods should be carefully chosen and tested for each particular media. Here we mainly focus on sequential process-based method due to its general simplicity and straightforward usability for different transformation modeling: diagenesis, mechanical compaction, erosion, etc. It is well known that process-based models for sandstone thin-sections give good transport properties after 3D reconstruction. This method is also useful for pore-network extraction validation. At first, polydisperse sphere packs are created using two different techniques: (1) modified Lubachevsky-Stillinger method, and (2) original Øren-Bakke method with global minimal or local minimal energy ballistic disposition rules. The latter are known to create anisotropic packs with kissing numbers different from real sedimentary materials. During the next step, the third phase (clay minerals for rocks and clay and organic matter for soils) is grown within pore space based on Voronoi tesselation to determine distances to the nearest grains. Input parameters, i.e., grain size distributions and porosities are determined using laboratory methods or image analysis for real porous media: sandstones, sandy soils and soil aggregates. To model soil aggregate structure a gravitational algorithm is used there a set of granules falls onto a gravity center in the middle of the aggregate. All further steps are similar to that of sedimentary rocks and soils. Resulted 3D reconstructions are compared with original 3D structures obtained using X

  1. Uranium partitioning under acidic conditions in a sandy soil aquifer

    SciTech Connect

    Johnson, W.H. |; Serkiz, S.M.; Johnson, L.M.

    1995-07-01

    The partitioning of uranium in an aquifer down gradient of two large mixed waste sites was examined with respect to the solution and soil chemistry (e.g., pH redox potential and contaminant concentration) and aqueous-phase chemical speciation. This involved generation of field-derived, batch sorption, and reactive mineral surface sorption data. Field-derived distribution coefficients for uranium at these waste sites were found to vary between 0.40 and 15,000. Based on thermodynamic speciation modeling and a comparison of field and laboratory data, gibbsite is a potential reactive mineral surface present in modified soils at the sites. Uranium partitioning data are presented from field samples and laboratory studies of background soil and the mineral surface gibbsite. Mechanistic and empirical sorption models fit to the field-derived uranium partitioning data show an improvement of over two orders of magnitude, as measured by the normalized sum of errors squared, when compared with the single K{sub d} model used in previous risk work. Models fit to batch sorption data provided a better fit of sorbed uranium than do models fit to the field-derived data.

  2. Measurement and computation of movement of bromide ions and carbofuran in ridged humic-sandy soil.

    PubMed

    Leistra, Minze; Boesten, Jos J T I

    2010-07-01

    Water flow and pesticide transport in the soil of fields with ridges and furrows may be more complex than in the soil of more level fields. Prior to crop emergence, the tracer bromide ion and the insecticide carbofuran were sprayed on the humic-sandy soil of a potato field with ridges and furrows. Rainfall was supplemented by sprinkler irrigation. The distribution of the substances in the soil profile of the ridges and furrows was measured on three dates in the potato growing season. Separate ridge and furrow systems were simulated by using the pesticide emission assessment at regional and local scales (PEARL) model for pesticide behavior in soil-plant systems. The substances travelled deeper in the furrow soil than in the ridge soil, because of runoff from the ridges to the furrows. At 19 days after application, the peak of the bromide distribution was measured to be in the 0.1-0.2 m layer of the ridges, while it was in the 0.3-0.5 m layer of the furrows. After 65 days, the peak of the carbofuran distribution in the ridge soil was still in the 0.1 m top layer, while the pesticide was rather evenly distributed in the top 0.6 m of the furrow soil. The wide ranges in concentration measured with depth showed that preferential water flow and substance transport occurred in the sandy soil. Part of the bromide ion distribution was measured to move faster in soil than the computed wave. The runoff of water and pesticide from the ridges to the furrows, and the thinner root zone in the furrows, are expected to increase the risk of leaching to groundwater in ridged fields, in comparison with more level fields.

  3. Measurement and computation of movement of bromide ions and carbofuran in ridged humic-sandy soil.

    PubMed

    Leistra, Minze; Boesten, Jos J T I

    2010-07-01

    Water flow and pesticide transport in the soil of fields with ridges and furrows may be more complex than in the soil of more level fields. Prior to crop emergence, the tracer bromide ion and the insecticide carbofuran were sprayed on the humic-sandy soil of a potato field with ridges and furrows. Rainfall was supplemented by sprinkler irrigation. The distribution of the substances in the soil profile of the ridges and furrows was measured on three dates in the potato growing season. Separate ridge and furrow systems were simulated by using the pesticide emission assessment at regional and local scales (PEARL) model for pesticide behavior in soil-plant systems. The substances travelled deeper in the furrow soil than in the ridge soil, because of runoff from the ridges to the furrows. At 19 days after application, the peak of the bromide distribution was measured to be in the 0.1-0.2 m layer of the ridges, while it was in the 0.3-0.5 m layer of the furrows. After 65 days, the peak of the carbofuran distribution in the ridge soil was still in the 0.1 m top layer, while the pesticide was rather evenly distributed in the top 0.6 m of the furrow soil. The wide ranges in concentration measured with depth showed that preferential water flow and substance transport occurred in the sandy soil. Part of the bromide ion distribution was measured to move faster in soil than the computed wave. The runoff of water and pesticide from the ridges to the furrows, and the thinner root zone in the furrows, are expected to increase the risk of leaching to groundwater in ridged fields, in comparison with more level fields. PMID:20041324

  4. Effects of vegetable oil residue after soil extraction on physical-chemical properties of sandy soil and plant growth.

    PubMed

    Gong, Zongqiang; Li, Peijun; Wilke, B M; Alef, Kassem

    2008-01-01

    Vegetable oil has the ability to extract polycyclic aromatic hydrocarbons (PAHs) from contaminated sandy soil for a remediation purpose, with some of the oil remaining in the soil. Although most of the PAHs were removed, the risk of residue oil in the soil was not known. The objective of this study was to evaluate the effects of the vegetable oil residue on higher plant growth and sandy soil properties after soil extraction for a better understanding of the soil remediation. Addition of sunflower oil and column experiment were performed on a PAH contaminated soil and/or a control soil, respectively. Soils were incubated for 90 d, and soil pH was measured during the soil incubation. Higher plant growth bioassays with Avena sativa L. (oat) and Brassica rapa L. (turnip) were performed after the incubation, and then soil organic carbon contents were measured. The results show that both the nutrient amendment and the sunflower oil degradation resulted in the decrease of soil pH. When these two process worked together, their effects were counteracted due to the consumption of the nutrients and oil removal, resulting in different pH profiles. Growth of A. sativa was adversely affected by the sunflower oil, and the nutrient amendments stimulated the A. sativa growth significantly. B. rapa was more sensitive to the sunflower oil than A. sativa. Only 1% sunflower oil addition plus nutrient amendment stimulated B. rapa growth. All the other treatments on B. rapa inhibited its growth significantly. The degradation of the sunflower oil in the soils was proved by the soil organic carbon content.

  5. Effects of vegetable oil residue after soil extraction on physical-chemical properties of sandy soil and plant growth.

    PubMed

    Gong, Zongqiang; Li, Peijun; Wilke, B M; Alef, Kassem

    2008-01-01

    Vegetable oil has the ability to extract polycyclic aromatic hydrocarbons (PAHs) from contaminated sandy soil for a remediation purpose, with some of the oil remaining in the soil. Although most of the PAHs were removed, the risk of residue oil in the soil was not known. The objective of this study was to evaluate the effects of the vegetable oil residue on higher plant growth and sandy soil properties after soil extraction for a better understanding of the soil remediation. Addition of sunflower oil and column experiment were performed on a PAH contaminated soil and/or a control soil, respectively. Soils were incubated for 90 d, and soil pH was measured during the soil incubation. Higher plant growth bioassays with Avena sativa L. (oat) and Brassica rapa L. (turnip) were performed after the incubation, and then soil organic carbon contents were measured. The results show that both the nutrient amendment and the sunflower oil degradation resulted in the decrease of soil pH. When these two process worked together, their effects were counteracted due to the consumption of the nutrients and oil removal, resulting in different pH profiles. Growth of A. sativa was adversely affected by the sunflower oil, and the nutrient amendments stimulated the A. sativa growth significantly. B. rapa was more sensitive to the sunflower oil than A. sativa. Only 1% sunflower oil addition plus nutrient amendment stimulated B. rapa growth. All the other treatments on B. rapa inhibited its growth significantly. The degradation of the sunflower oil in the soils was proved by the soil organic carbon content. PMID:19209632

  6. Movement of petroleum hydrocarbons in sandy coastal soils.

    PubMed

    Daniels, R; Davies, J; Gravell, A; Rowland, P

    2000-12-01

    In a field trial, oiled beach sand was buried in a coastal dune system in south Wales. A monitoring programme was designed to assess the rate of leaching of inorganic ions and hydrocarbons from the deposit. Active breakdown of the weathered oil occurred within the oiled beach sand, but hydrocarbons from the original material, or arising as a result of degradation, did not follow the same leaching pattern as inorganic ions; they remained within the original deposit. The results suggest that weathered oil coming ashore from spills at sea can be mixed with sand and buried to degrade in coastal soils, without risk of groundwater contamination by hydrocarbons.

  7. Relationships between water infiltration and oil spill migration in sandy soils

    NASA Astrophysics Data System (ADS)

    Kessler, Avner; Rubin, Hillel

    1987-06-01

    This article summarizes a study directed towards the prediction of oil spill migration in sandy soils. Such a prediction is needed for the design of remedial measures against soil and groundwater contamination. The geneal approach in this study is to convert available data concerning water infiltration into equivalent unknown data concerning oil spillage. This information is then fed into a numerical model by which the oil spill migration is simulated. Laboratory measurements including retention curve, hydraulic conductivity and infiltration rate, were made separately for water and kerosene in order to evaluate and confirm the suggested approach.

  8. Copper bioavailability and fractionation in copper-contaminated sandy soils in the wet subtropics (southern Brazil).

    PubMed

    Mirlean, Nicolai; Baisch, Paulo; Medeanic, Svetlana

    2009-03-01

    We studied the distribution, bioavailability and speciation of copper in subtropical sandy soils exposed to long-term applications of copper-based fungicide. In the surface horizon of the contaminated soils, bioavailable copper surpasses the toxic threshold for plants up to several times. Mobile fractions of copper predominate in top layers, contributing to contamination spreading downward to groundwater. Copper accumulates on the underlying iron hydroxide barrier in quantities comparable to total copper concentrations in the surface horizon. Despite the impediment of the geochemical barrier, most applied copper reaches the aquifer, contaminating the groundwater.

  9. Alum amendment effects on phosphorus release and distribution in poultry litter-amended sandy soils

    USGS Publications Warehouse

    Staats, K.E.; Arai, Y.; Sparks, D.L.

    2004-01-01

    Increased poultry production has contributed to excess nutrient problems in Atlantic Coastal Plain soils due to land application of poultry litter (PL). Aluminum sulfate [alum, Al2(SO4)3?? 14H2O] amendment of PL effectively reduces soluble phosphorus (P) in the PL; however, the effects of these litters when added to acidic, sandy soils are not well understood. The objective of this study was to investigate the efficacy of alum-amended poultry litter in reducing P release from three Delaware Coastal Plain soils: Evesboro loamy sand (Ev; excessively drained, mesic, coated Typic Quartzipsamments), Rumford loamy sand (Ru; well drained, coarse-loamy, siliceous, subactive, thermic Typic Hapludults), and Pocomoke sandy loam (Pm; very poorly drained, coarse-loamy, siliceous, active, thermic Typic Umbraquults). Long-term (25 d) and short-term (24 h) desorption studies were conducted, in addition to chemical extractions and kinetic modeling, to observe the changes that alum-amended versus unamended PL caused in the soils. The Ev, Ru, and Pm soils were incubated with 9 Mg ha-1 of alum-amended or unamended PL. Long-term desorption (25 d) of the incubated material resulted in approximately 13.5% (Ev), 12.7% (Ru), and 13.3% (Pm) reductions in cumulative P desorbed when comparing soil treated with unamended and alum-amended PL. In addition, the P release from the soil treated with alum-amended litter was not significantly different from the control (soil alone). Short-term desorption (24 h) showed 7.3% (Ev), 15.4% (Ru), and 20% (Pm) reductions. The overall implication from this study is that the use of alum as a PL amendment is useful in coarse-textured soils of the Coastal Plain. With increased application of alum-amended PL, more significant decreases may be possible with little or no effect on soil quality.

  10. Imidacloprid sorption kinetics, equilibria, and degradation in sandy soils of Florida.

    PubMed

    Leiva, Jorge A; Nkedi-Kizza, Peter; Morgan, Kelly T; Qureshi, Jawwad A

    2015-05-27

    Imidacloprid (IMD) is a neonicotinoid insecticide soil-drenched on sandy soils of southwest Florida for the control of Diaphorina citri Kuwayama or Asian citrus psyllid (ACP). The ACP vectors causal pathogens of a devastating citrus disease called citrus greening. Understanding the behavior of IMD in these soils and plants is critical to its performance against target pests. Samples from Immokalee fine sand (IFS) were used for sorption kinetics and equilibria experiments. IMD kinetics data were described by the one-site mass transfer (OSMT) model and reached equilibrium between 6 and 12 h. Batch equilibrium and degradation studies revealed that IMD was weakly sorbed (K(OC) = 163-230) and persistent, with a half-life of 1.0-2.6 years. Consequently, IMD has the potential to leach below the citrus root zone after the soil-drench applications. PMID:25938475

  11. Fit-for-purpose phosphorus management: do riparian buffers qualify in catchments with sandy soils?

    PubMed

    Weaver, David; Summers, Robert

    2014-05-01

    Hillslope runoff and leaching studies, catchment-scale water quality measurements and P retention and release characteristics of stream bank and catchment soils were used to better understand reasons behind the reported ineffectiveness of riparian buffers for phosphorus (P) management in catchments with sandy soils from south-west Western Australia (WA). Catchment-scale water quality measurements of 60 % particulate P (PP) suggest that riparian buffers should improve water quality; however, runoff and leaching studies show 20 times more water and 2 to 3 orders of magnitude more P are transported through leaching than runoff processes. The ratio of filterable reactive P (FRP) to total P (TP) in surface runoff from the plots was 60 %, and when combined with leachate, 96 to 99 % of P lost from hillslopes was FRP, in contrast with 40 % measured as FRP at the large catchment scale. Measurements of the P retention and release characteristics of catchment soils (<2 mm) compared with stream bank soil (<2 mm) and the <75-μm fraction of stream bank soils suggest that catchment soils contain more P, are more P saturated and are significantly more likely to deliver FRP and TP in excess of water quality targets than stream bank soils. Stream bank soils are much more likely to retain P than contribute P to streams, and the in-stream mixing of FRP from the landscape with particulates from stream banks or stream beds is a potential mechanism to explain the change in P form from hillslopes (96 to 99 % FRP) to large catchments (40 % FRP). When considered in the context of previous work reporting that riparian buffers were ineffective for P management in this environment, these studies reinforce the notion that (1) riparian buffers are unlikely to provide fit-for-purpose P management in catchments with sandy soils, (2) most P delivered to streams in sandy soil catchments is FRP and travels via subsurface and leaching pathways and (3) large catchment-scale water quality measurements

  12. Transfer of cadmium from a sandy acidic soil to man: A population study

    SciTech Connect

    Staessen, J.A.; Celis, H.G.; Fagard, R.H.; Lijnen, P.J.; Thijs, L.B.; Amery, A.K. ); Vyncke, G. ); Lauwerys, R.R.; Roels, H.A. ); Claeys, F. ); Dondeyne, F. ); Ide, G. ); Rondia, D.; Sartor, F. )

    1992-06-01

    This population study included 230 subjects (age range 20-83 years) who consumed vegetables grown in kitchen gardens on a sandy acidic soil (mean pH {approximately}6.3). The study investigated the association between the Cd (cadmium) levels in blood and urine and the Cd concentration in the soil (range 0.2-44 ppm). Seventy-six subjects were current smokers and 122 participants lived in a district with known Cd pollution. Urinary Cd in the 230 subjects averaged 8.7 nmole/24 hr, (range 1.3 to 47 nmole/24 hr) after age adjustment positively correlated with the Cd level in the soil; a twofold increase of the Cd concentration in the soil was accompanied by a 7% rise in urinary Cd in men and by a 4% rise in women. Blood Cd averaged 11.5 nmole/liter (range 1.8-41 nmole/liter) and was negatively associated with the Cd level in the soil. After adjustment for significant covariates (smoking and serum {gamma}-glutamyl transpeptidase in both sexes, and age and serum ferritin in women), a twofold increase in the Cd concentration in the soil was accompanied by a 6% decrease in blood Cd in men and by a 10% decrease in women. In conclusion, in a rural population, consuming vegetables grown on a sandy acidic soil, 2 to 4% of the variance of urinary Cd was directly related to the Cd level in the soil. The negative correlation with blood Cd, a measure of more recent exposure, was biased by the implementation of preventive measures in the polluted district.

  13. Aerobic biodegradation of 4-methylquinoline by a soil bacterium.

    PubMed Central

    Sutton, S D; Pfaller, S L; Shann, J R; Warshawsky, D; Kinkle, B K; Vestal, J R

    1996-01-01

    Methylquinolines and related N-heterocyclic aromatic compounds are common contaminants associated with the use of hydrocarbons in both coal gasification and wood treatment processes. These compounds have been found in groundwater, and many are known mutagens. A stable, five-member bacterial consortium able to degrade 4-methylquinoline was established by selective enrichment using soil collected from an abandoned coal gasification site. The consortium was maintained for 5 years by serial transfer in a medium containing 4-methylquinoline. A gram-negative soil bacterium, strain Lep1, was isolated from the consortium and shown to utilize 4-methylquinoline as a source of carbon and energy during growth in liquid medium. A time course experiment demonstrated that both the isolate Lep1 and the consortium containing Lep1 were able to degrade 4-methylquinoline under aerobic conditions. Complete degradation of 4-methylquinoline by either strain Lep1 alone or the consortium was characterized by the production and eventual disappearance of 2-hydroxy-4-methylquinoline, followed by the appearance and persistence of a second metabolite tentatively identified as a hydroxy-4-methylcoumarin. Currently, there is no indication that 4-methylquinoline degradation proceeds differently in the consortium culture compared with Lep1 alone. This is the first report of 4-methylquinoline biodegradation under aerobic conditions. PMID:8702284

  14. Carbon mineralization and nutrient availability in calcareous sandy soils amended with woody waste biochar.

    PubMed

    El-Naggar, Ahmed H; Usman, Adel R A; Al-Omran, Abdulrasoul; Ok, Yong Sik; Ahmad, Mahtab; Al-Wabel, Mohammad I

    2015-11-01

    Many studies have reported the positive effect of biochar on soil carbon sequestration and soil fertility improvement in acidic soils. However, biochar may have different impacts on calcareous sandy soils. A 90-day incubation experiment was conducted to quantify the effects of woody waste biochar (10 g kg(-1)) on CO2-C emissions, K2SO4-extractable C and macro-(N, P and K) and micro-(Fe, Mn, Zn and Cu) nutrient availability in the presence or absence of poultry manure (5 g kg(-1) soil). The following six treatments were applied: (1) conocarpus (Conocarpus erectus L.) waste (CW), (2) conocarpus biochar (BC), (3) poultry manure (PM), (4) PM+CW, (5) PM+BC and (6) untreated soil (CK). Poultry manure increased CO2-C emissions and K2SO4-extractable C, and the highest increases in CO2-C emission rate and cumulative CO2-C and K2SO4-extractable C were observed for the PM+CW treatment. On the contrary, treatments with BC halted the CO2-C emission rate, indicating that the contribution of BC to CO2-C emissions is negligible compared with the soils amended with CW and PM. Furthermore, the combined addition of PM+BC increased available N, P and K compared with the PM or BC treatments. Overall, the incorporation of biochar into calcareous soils might have benefits in carbon sequestration and soil fertility improvement. PMID:26037818

  15. Biochar pyrolyzed at two temperatures affects Escherichia coli transport through a sandy soil.

    PubMed

    Bolster, Carl H; Abit, Sergio M

    2012-01-01

    The incorporation of biochar into soils has been proposed as a means to sequester carbon from the atmosphere. An added environmental benefit is that biochar has also been shown to increase soil retention of nutrients, heavy metals, and pesticides. The goal of this study was to evaluate whether biochar amendments affect the transport of Escherichia coli through a water-saturated soil. We looked at the transport of three E. coli isolates through 10-cm columns packed with a fine sandy soil amended with 2 or 10% (w/w) poultry litter biochar pyrolyzed at 350 or 700°C. For all three isolates, mixing the high-temperature biochar at a rate of 2% into the soil had no impact on transport behavior. When added at a rate of 10%, a reduction of five orders of magnitude in the amount of E. coli transported through the soil was observed for two of the isolates, and a 60% reduction was observed for the third isolate. Mixing the low-temperature biochar into the soil resulted in enhanced transport through the soil for two of the isolates, whereas no significant differences in transport behavior were observed between the low-temperature and high-temperature biochar amendments for one isolate. Our results show that the addition of biochar can affect the retention and transport behavior of E. coli and that biochar application rate, biochar pyrolysis temperature, and bacterial surface characteristics were important factors determining the transport of E. coli through our test soil. PMID:22218181

  16. [Community structure and diversity of soil arthropods in naturally restored sandy grasslands after grazing].

    PubMed

    Liu, Ren-tao; Zhao, Ha-lin; Zhao, Xue-yong

    2010-11-01

    Taking the Naiman Desertification Research Station under Chinese Academy of Sciences as a base, an investigation was conducted on the community structure of soil arthropods in the naturally restored sandy grasslands after different intensity grazing disturbance, with the effects of vegetation and soil on this community structure approached. In the non-grazing grassland, soil arthropods were rich in species and more in individuals, and had the highest diversity. In the restored grassland after light grazing, soil arthropods had the lowest evenness and diversity. In the restored grassland after moderate grazing, the individuals of soil arthropods were lesser but the major groups were more, and the evenness and diversity were higher. In the restored grassland after heavy grazing, the individuals of soil arthropods were more but the major groups were lesser, and the diversity was higher. Plant individuals' number, vegetation height and coverage, and soil alkalinity were the main factors affecting the soil arthropod community in naturally restored grasslands after different intensity grazing disturbance. It was implied that after 12-year exclosure of grassland, soil arthropod community could be recovered to some degree, while grazing disturbance had long-term negative effects on the arthropod community.

  17. [Community structure and diversity of soil arthropods in naturally restored sandy grasslands after grazing].

    PubMed

    Liu, Ren-tao; Zhao, Ha-lin; Zhao, Xue-yong

    2010-11-01

    Taking the Naiman Desertification Research Station under Chinese Academy of Sciences as a base, an investigation was conducted on the community structure of soil arthropods in the naturally restored sandy grasslands after different intensity grazing disturbance, with the effects of vegetation and soil on this community structure approached. In the non-grazing grassland, soil arthropods were rich in species and more in individuals, and had the highest diversity. In the restored grassland after light grazing, soil arthropods had the lowest evenness and diversity. In the restored grassland after moderate grazing, the individuals of soil arthropods were lesser but the major groups were more, and the evenness and diversity were higher. In the restored grassland after heavy grazing, the individuals of soil arthropods were more but the major groups were lesser, and the diversity was higher. Plant individuals' number, vegetation height and coverage, and soil alkalinity were the main factors affecting the soil arthropod community in naturally restored grasslands after different intensity grazing disturbance. It was implied that after 12-year exclosure of grassland, soil arthropod community could be recovered to some degree, while grazing disturbance had long-term negative effects on the arthropod community. PMID:21361009

  18. Toluene Removal from Sandy Soils via In Situ Technologies with an Emphasis on Factors Influencing Soil Vapor Extraction

    PubMed Central

    Amin, Mohammad Mehdi; Hatamipour, Mohammad Sadegh; Nourmoradi, Heshmatollah; Farhadkhani, Marzieh; Mohammadi-Moghadam, Fazel

    2014-01-01

    The integration of bioventing (BV) and soil vapor extraction (SVE) appears to be an effective combination method for soil decontamination. This paper serves two main purposes: it evaluates the effects of soil water content (SWC) and air flow rate on SVE and it investigates the transition regime between BV and SVE for toluene removal from sandy soils. 96 hours after air injection, more than 97% removal efficiency was achieved in all five experiments (carried out for SVE) including 5, 10, and 15% for SWC and 250 and 500 mL/min for air flow rate on SVE. The highest removal efficiency (>99.5%) of toluene was obtained by the combination of BV and SVE (AIBV: Air Injection Bioventing) after 96 h of air injection at a constant flow rate of 250 mL/min. It was found that AIBV has the highest efficiency for toluene removal from sandy soils and can remediate the vadose zone effectively to meet the soil guideline values for protection of groundwater. PMID:24587723

  19. Toluene removal from sandy soils via in situ technologies with an emphasis on factors influencing soil vapor extraction.

    PubMed

    Amin, Mohammad Mehdi; Hatamipour, Mohammad Sadegh; Momenbeik, Fariborz; Nourmoradi, Heshmatollah; Farhadkhani, Marzieh; Mohammadi-Moghadam, Fazel

    2014-01-01

    The integration of bioventing (BV) and soil vapor extraction (SVE) appears to be an effective combination method for soil decontamination. This paper serves two main purposes: it evaluates the effects of soil water content (SWC) and air flow rate on SVE and it investigates the transition regime between BV and SVE for toluene removal from sandy soils. 96 hours after air injection, more than 97% removal efficiency was achieved in all five experiments (carried out for SVE) including 5, 10, and 15% for SWC and 250 and 500 mL/min for air flow rate on SVE. The highest removal efficiency (>99.5%) of toluene was obtained by the combination of BV and SVE (AIBV: Air Injection Bioventing) after 96 h of air injection at a constant flow rate of 250 mL/min. It was found that AIBV has the highest efficiency for toluene removal from sandy soils and can remediate the vadose zone effectively to meet the soil guideline values for protection of groundwater.

  20. Does thermal carbonization (Biochar) of organic material increase more merits for their amendments of sandy soil?

    NASA Astrophysics Data System (ADS)

    Wu, Y.; Xu, G.; Sun, J. N.; Shao, H. B.

    2014-02-01

    Organic materials (e.g. furfural residue) are generally believed to improve the physical and chemical properties of the soils with low fertility. Recently, biochar have been received more attention as a possible measure to improve the carbon balance and improve soil quality in some degraded soils. However, little is known about their different amelioration of a sandy saline soil. In this study, 56d incubation experiment was conducted to evaluate the influence of furfural and its biochar on the properties of saline soil. The results showed that both furfural and biochar greatly reduced pH, increased soil organic carbon (SOC) content and cation exchange capacity (CEC), and enhanced the available phosphorus (P) in the soil. Furfural is more efficient than biochar in reducing pH: 5% furfural lowered the soil pH by 0.5-0.8 (soil pH: 8.3-8.6), while 5% biochar decreased by 0.25-0.4 due to the loss of acidity in pyrolysis process. With respect to available P, 5% of the furfural addition increased available P content by 4-6 times in comparison to 2-5 times with biochar application. In reducing soil exchangeable sodium percentage (ESP), biochar is slightly superior to furfural because soil ESP reduced by 51% and 43% with 5% furfural and 5% biochar addition at the end of incubation. In addition, no significant differences were observed between furfural and biochar about their capacity to retain N, P in leaching solution and to increase CEC in soil. These facts may be caused by the relatively short incubation time. In general, furfural and biochar have different amendments depending on soil properties: furfural was more effectively to decrease pH and to increase available P, whereas biochar played a more important role in increasing SOC and reducing ESP of saline soil.

  1. Effects of long-term amendment of organic manure and nitrogen fertilizer on nitrous oxide emission in a sandy loam soil.

    PubMed

    Ding, Wei-xin; Meng, Lei; Cai, Zu-cong; Han, Feng-xiang

    2007-01-01

    To understand the effects of long-term amendment of organic manure and N fertilizer on N2O emission in the North China Plain, a laboratory incubation at different temperatures and soil moistures were carried out using soils treated with organic manure (OM), half organic manure plus half fertilizer N (HOM), fertilizer NPK (NPK), fertilizer NP (NP), fertilizer NK (NK), fertilizer PK (NK) and control (CK) since 1989. Cumulative N2O emission in OM soil during the 17 d incubation period was slightly higher than in NPK soil under optimum nitrification conditions (25 degrees C and 60% water-filled pore space, WFPS), but more than twice under the optimum denitrification conditions (35 degrees C and 90% WFPS). N2O produced by denitrification was 2.1-2.3 times greater than that by nitrification in OM and HOM soils, but only 1.5 times greater in NPK and NP soils. These results implied that the long-term amendment of organic manure could significantly increase the N2O emission via denitrification in OM soil as compared to NPK soil. This is quite different from field measurement between OM soil and NPK soil. Substantial inhibition of the formation of anaerobic environment for denitrification in field might result in no marked difference in N2O emission between OM and NPK soils. This is due in part to more rapid oxygen diffusion in coarse textured soils than consumption by aerobic microbes until WFPS was 75% and to low easily decomposed organic C of organic manure. This finding suggested that addition of organic manure in the tested sandy loam might be a good management option since it seldom caused a burst of N2O emission but sequestered atmospheric C and maintained efficiently applied N in soil.

  2. Ethylcellulose formulations for controlled release of the herbicide alachlor in a sandy soil.

    PubMed

    Sopeña, Fátima; Cabrera, Alegría; Maqueda, Celia; Morillo, Esmeralda

    2007-10-01

    The development of controlled-release formulations of alachlor to diminish its leaching in sandy soils, avoiding groundwater contamination and maintaining its efficacy, was studied. For this purpose, ethylcellulose (EC) microencapsulated formulations (MEFs) of alachlor were prepared under different conditions and applied to soil columns to study their mobility. The results show that in all cases the release into water of alachlor from MEFs was retarded when compared with commercial formulation. Total leaching losses in soil columns were reduced to 59% from 98%. The mobility of alachlor from EC microspheres into soil columns has been greatly diminished in comparison with its current commercial formulation (CF), above all with increasing EC/herbicide ratios. Distribution of alachlor applied as MEFs at different depths in the soil was higher in the soil surface (66.3-81.3% of herbicide applied at the first 12 cm). In contrast, the residues from CF along the complete soil column were only 20.4%. From the results of bioassays, MEFs showed a higher efficacy than CF at 30 days after the treatment. The use of ME formulations could provide an advantage in minimizing the risk of groundwater contamination by alachlor and reducing the application rates, as a result of maintaining the desired concentration of the herbicide in the top soil layer, obtaining longer periods of weed control.

  3. Microbial removal of atmospheric carbon tetrachloride in bulk aerobic soils.

    PubMed

    Mendoza, Y; Goodwin, K D; Happell, J D

    2011-09-01

    Atmospheric concentrations of carbon tetrachloride (CCl(4)) were removed by bulk aerobic soils from tropical, subtropical, and boreal environments. Removal was observed in all tested soil types, indicating that the process was widespread. The flux measured in field chamber experiments was 0.24 ± 0.10 nmol CCl(4) (m(2) day)(-1) (average ± standard deviation [SD]; n = 282). Removal of CCl(4) and removal of methane (CH(4)) were compared to explore whether the two processes were linked. Removal of both gases was halted in laboratory samples that were autoclaved, dry heated, or incubated in the presence of mercuric chloride (HgCl(2)). In marl soils, treatment with antibiotics such as tetracycline and streptomycin caused partial inhibition of CCl(4) (50%) and CH(4) (76%) removal, but removal was not affected in soils treated with nystatin or myxothiazol. These data indicated that bacteria contributed to the soil removal of CCl(4) and that microeukaryotes may not have played a significant role. Amendments of methanol, acetate, and succinate to soil samples enhanced CCl(4) removal by 59%, 293%, and 72%, respectively. Additions of a variety of inhibitors and substrates indicated that nitrification, methanogenesis, or biological reduction of nitrate, nitrous oxide, or sulfate (e.g., occurring in possible anoxic microzones) did not play a significant role in the removal of CCl(4). Methyl fluoride inhibited removal of CH(4) but not CCl(4), indicating that CH(4) and CCl(4) removals were not directly linked. Furthermore, CCl(4) removal was not affected in soils amended with copper sulfate or methane, supporting the results with MeF and suggesting that the observed CCl(4) removal was not significantly mediated by methanotrophs.

  4. In situ measurements of nitrate leaching implicate poor nitrogen and irrigation management on sandy soils.

    PubMed

    Gehl, R J; Schmidt, J P; Stone, L R; Schlegel, A J; Clark, G A

    2005-01-01

    Minimizing the risk of nitrate contamination along the waterways of the U.S. Great Plains is essential to continued irrigated corn production and quality water supplies. The objectives of this study were to quantify nitrate (NO(3)) leaching for irrigated sandy soils (Pratt loamy fine sand [sandy, mixed, mesic Lamellic Haplustalfs]) and to evaluate the effects of N fertilizer and irrigation management strategies on NO(3) leaching in irrigated corn. Two irrigation schedules (1.0x and 1.25x optimum) were combined with six N fertilizer treatments broadcast as NH(4)NO(3) (kg N ha(-1)): 300 and 250 applied pre-plant; 250 applied pre-plant and sidedress; 185 applied pre-plant and sidedress; 125 applied pre-plant and sidedress; and 0. Porous-cup tensiometers and solution samplers were installed in each of the four highest N treatments. Soil solution samples were collected during the 2001 and 2002 growing seasons. Maximum corn grain yield was achieved with 125 or 185 kg N ha(-1), regardless of the irrigation schedule (IS). The 1.25x IS exacerbated the amount of NO(3) leached below the 152-cm depth in the preplant N treatments, with a mean of 146 kg N ha(-1) for the 250 and 300 kg N preplant applications compared with 12 kg N ha(-1) for the same N treatments and 1.0x IS. With 185 kg N ha(-1), the 1.25x IS treatment resulted in 74 kg N ha(-1) leached compared with 10 kg N ha(-1) for the 1.0x IS. Appropriate irrigation scheduling and N fertilizer rates are essential to improving N management practices on these sandy soils.

  5. Estimation of Nitrogen Pools in Irrigated Potato Production on Sandy Soil Using the Model SUBSTOR

    PubMed Central

    Prasad, Rishi; Hochmuth, George J.; Boote, Kenneth J.

    2015-01-01

    Recent increases in nitrate concentrations in the Suwannee River and associated springs in northern Florida have raised concerns over the contributions of non-point sources. The Middle Suwannee River Basin (MSRB) is of special concern because of prevalent karst topography, unconfined aquifers and sandy soils which increase vulnerability of the ground water contamination from agricultural operations- a billion dollar industry in this region. Potato (Solanum tuberosum L.) production poses a challenge in the area due to the shallow root system of potato plants, and low water and nutrient holding capacity of the sandy soils. A four-year monitoring study for potato production on sandy soil was conducted on a commercial farm located in the MSRB to identify major nitrogen (N) loss pathways and determine their contribution to the total environmental N load, using a partial N budget approach and the potato model SUBSTOR. Model simulated environmental N loading rates were found to lie within one standard deviation of the observed values and identified leaching loss of N as the major sink representing 25 to 38% (or 85 to 138 kg ha-1 N) of the total input N (310 to 349 kg ha-1 N). The crop residues left in the field after tuber harvest represented a significant amount of N (64 to 110 kg ha-1N) and posed potential for indirect leaching loss of N upon their mineralization and the absence of subsequent cover crops. Typically, two months of fallow period exits between harvest of tubers and planting of the fall row crop (silage corn). The fallow period is characterized by summer rains which pose a threat to N released from rapidly mineralizing potato vines. Strategies to reduce N loading into the groundwater from potato production must focus on development and adoption of best management practices aimed on reducing direct as well as indirect N leaching losses. PMID:25635904

  6. Estimation of nitrogen pools in irrigated potato production on sandy soil using the model SUBSTOR.

    PubMed

    Prasad, Rishi; Hochmuth, George J; Boote, Kenneth J

    2015-01-01

    Recent increases in nitrate concentrations in the Suwannee River and associated springs in northern Florida have raised concerns over the contributions of non-point sources. The Middle Suwannee River Basin (MSRB) is of special concern because of prevalent karst topography, unconfined aquifers and sandy soils which increase vulnerability of the ground water contamination from agricultural operations--a billion dollar industry in this region. Potato (Solanum tuberosum L.) production poses a challenge in the area due to the shallow root system of potato plants, and low water and nutrient holding capacity of the sandy soils. A four-year monitoring study for potato production on sandy soil was conducted on a commercial farm located in the MSRB to identify major nitrogen (N) loss pathways and determine their contribution to the total environmental N load, using a partial N budget approach and the potato model SUBSTOR. Model simulated environmental N loading rates were found to lie within one standard deviation of the observed values and identified leaching loss of N as the major sink representing 25 to 38% (or 85 to 138 kg ha(-1) N) of the total input N (310 to 349 kg ha(-1) N). The crop residues left in the field after tuber harvest represented a significant amount of N (64 to 110 kg ha(-1) N) and posed potential for indirect leaching loss of N upon their mineralization and the absence of subsequent cover crops. Typically, two months of fallow period exits between harvest of tubers and planting of the fall row crop (silage corn). The fallow period is characterized by summer rains which pose a threat to N released from rapidly mineralizing potato vines. Strategies to reduce N loading into the groundwater from potato production must focus on development and adoption of best management practices aimed on reducing direct as well as indirect N leaching losses.

  7. Nitrogen availability and indirect measurements of greenhouse gas emissions from aerobic and anaerobic biowaste digestates applied to agricultural soils

    SciTech Connect

    Rigby, H.; Smith, S.R.

    2013-12-15

    Highlights: • Nitrogen release in digestate-amended soil depends on the digestate type. • Overall N release is modulated by digestate mineral and mineralisable N contents. • Microbial immobilisation does not influence overall release of digestate N in soil. • Digestate physical properties and soil type interact to affect overall N recovery. • High labile C inputs in digestate may promote denitrification in fine-textured soil. - Abstract: Recycling biowaste digestates on agricultural land diverts biodegradable waste from landfill disposal and represents a sustainable source of nutrients and organic matter (OM) to improve soil for crop production. However, the dynamics of nitrogen (N) release from these organic N sources must be determined to optimise their fertiliser value and management. This laboratory incubation experiment examined the effects of digestate type (aerobic and anaerobic), waste type (industrial, agricultural and municipal solid waste or sewage sludge) and soil type (sandy loam, sandy silt loam and silty clay) on N availability in digestate-amended soils and also quantified the extent and significance of the immobilisation of N within the soil microbial biomass, as a possible regulatory mechanism of N release. The digestate types examined included: dewatered, anaerobically digested biosolids (DMAD); dewatered, anaerobic mesophilic digestate from the organic fraction of municipal solid waste (DMADMSW); liquid, anaerobic co-digestate of food and animal slurry (LcoMAD) and liquid, thermophilic aerobic digestate of food waste (LTAD). Ammonium chloride (NH{sub 4}Cl) was included as a reference treatment for mineral N. After 48 days, the final, maximum net recoveries of mineral N relative to the total N (TN) addition in the different digestates and unamended control treatments were in the decreasing order: LcoMAD, 68%; LTAD, 37%, DMAD, 20%; and DMADMSW, 11%. A transient increase in microbial biomass N (MBN) was observed with LTAD application

  8. Bulk density, water content and hydraulic properties of a sandy loam soil following conventional or strip tillage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated the effects of conventional (CT) and strip (ST) tillage practices on bulk density ('b), water content ('w), infiltration rate (Ir) and hydraulic conductivity (Ks) of plots in a Lihen sandy loam soil during the 2007 and 2008 growing seasons. We measured 'b and 'w using soil cores collect...

  9. Tillage Effects on Bulk Density and Hydraulic Properties of a Sandy Loam Soil in the Mon-Dak Region, USA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We evaluated the effects of conventional (CT) and strip (ST) tillage practices on bulk density (BD), water content (MC), infiltration rate (Ir) and hydraulic conductivity (Ks) in a Lihen sandy loam soil. Soil cores were collected from each plot at 0 to 10 and 10 to 30 cm depths under each tillage pr...

  10. Estimating water retention curves for sandy soils at the Doñana National Park, SW Spain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The determination of soil water retention curves (SWRC) in the laboratory is a slow and tedious task, which is especially challenging for sandy soils due to their low water retention capacity and large water content changes for small pressure head differences. Due to spatial variability within larg...

  11. Aggregate-associated carbon and nitrogen in reclaimed sandy loam soils

    SciTech Connect

    Wick, A.F.; Stahl, P.D.; Ingram, L.J.

    2009-11-15

    Minimal research has been conducted on aggregate, C, and N in coarse-textured soils used to reclaim surface coal mine lands. Furthermore, little is known about the contribution different plant communities make to the recovery of aggregation in these soils. Two chronosequences of semiarid reclaimed sites with sandy loam soils were sampled under shrub- and grass-dominated communities. Aggregation, aggregate fractions, and associated C and N were measured. No definitive trends of increasing macroaggregates between sites were observed undershrubs; however, macro- and microaggregation was greater in the 16-yr-old (0.20 and 0.23 kg aggregate kg{sup -1} soil, respectively) than in the 5-yr-old soils (0.02 and 0.08 kg aggregate kg{sup -1} soil, respectively) under grasses. Although C and N concentrations were drastically reduced (50-75%) with mining activity between the <1-yr-old and native soils, aggregate C and N concentrations tinder shrubs and grasses were similar to each other and to the native soils in the 5-yr-old site. Sods under grass in the 16-yr-old site had lower available and aggregate-occluded C and N concentrations than the 5-yr-old site, while C and N concentrations did not change between 5- and 16-yr-old soils under shrubs. Conversely, aggregate C and N pool sizes under shrubs and grasses both increased with site age to conditions similar to those observed in the native soil. Reclaimed shrub site soils had consistently higher C concentrations in the older reclaimed sites (10 and 16 yr old) than the soils under grasses, indicating greater accumulation and retention of C and N in organic material under shrub than grass communities in semiarid reclaimed sites.

  12. Dynamics of carbon pools in post-agrogenic sandy soils of southern taiga of Russia

    PubMed Central

    2010-01-01

    Background Until recently, a lot of arable lands were abandoned in many countries of the world and, especially, in Russia, where about half a million square kilometers of arable lands were abandoned in 1961-2007. The soils at these fallows undergo a process of natural restoration (or self-restoration) that changes the balance of soil organic matter (SOM) supply and mineralization. Results A soil chronosequence study, covering the ecosystems of 3, 20, 55, 100, and 170 years of self-restoration in southern taiga zone, shows that soil organic content of mineral horizons remains relatively stable during the self-restoration. This does not imply, however, that SOM pools remain steady. The C/N ratio of active SOM reached steady state after 55 years, and increased doubly (from 12.5 - 15.6 to 32.2-33.8). As to the C/N ratio of passive SOM, it has been continuously increasing (from 11.8-12.7 to 19.0-22.8) over the 170 years, and did not reach a steady condition. Conclusion The results of the study imply that soil recovery at the abandoned arable sandy lands of taiga is incredibly slow process. Not only soil morphological features of a former ploughing remained detectable but also the balance of soil organic matter input and mineralization remained unsteady after 170 years of self-restoration. PMID:20420668

  13. Phytotoxicity and uptake of nitroglycerin in a natural sandy loam soil.

    PubMed

    Rocheleau, Sylvie; Kuperman, Roman G; Dodard, Sabine G; Sarrazin, Manon; Savard, Kathleen; Paquet, Louise; Hawari, Jalal; Checkai, Ronald T; Thiboutot, Sonia; Ampleman, Guy; Sunahara, Geoffrey I

    2011-11-15

    Nitroglycerin (NG) is widely used for the production of explosives and solid propellants, and is a soil contaminant of concern at some military training ranges. NG phytotoxicity data reported in the literature cannot be applied directly to development of ecotoxicological benchmarks for plant exposures in soil because they were determined in studies using hydroponic media, cell cultures, and transgenic plants. Toxicities of NG in the present studies were evaluated for alfalfa (Medicago sativa), barnyard grass (Echinochloa crusgalli), and ryegrass (Lolium perenne) exposed to NG in Sassafras sandy loam soil. Uptake and degradation of NG were also evaluated in ryegrass. The median effective concentration values for shoot growth ranged from 40 to 231 mg kg(-1) in studies with NG freshly amended in soil, and from 23 to 185 mg kg(-1) in studies with NG weathered-and-aged in soil. Weathering-and-aging NG in soil did not significantly affect the toxicity based on 95% confidence intervals for either seedling emergence or plant growth endpoints. Uptake studies revealed that NG was not accumulated in ryegrass but was transformed into dinitroglycerin in the soil and roots, and was subsequently translocated into the ryegrass shoots. The highest bioconcentration factors for dinitroglycerin of 685 and 40 were determined for roots and shoots, respectively. Results of these studies will improve our understanding of toxicity and bioconcentration of NG in terrestrial plants and will contribute to ecological risk assessment of NG-contaminated sites.

  14. Biochar application to sandy and loamy soils for agricultural nutrient management

    NASA Astrophysics Data System (ADS)

    Gronwald, Marco; Don, Axel; Tiemeyer, Baerbel; Helfrich, Mirjam

    2014-05-01

    Soil fertility of agricultural soils is challenged by nutrients losses and increasing soil acidification. Furthermore, leached nutrients negatively affect the quality of ground and surface water 1]. In addition to the possible soil carbon sequestration by applying biochars, many positive soil-improving properties are attributed to biochars. The application of biochars to agricultural - especially sandy - soils could reduce leaching of nutrients and may improve their availability 1,2]. Thus, biochar application to agricultural fields could be an ecologically and economically viable option to improve soils' fertility. However, biochar properties strongly depend on their feedstock and production process 3]. Various types of biochars (pyrolysis char, hydrochar (produced at 200 and 250° C); feedstocks: digestate, Miscanthus and wood chips) were used to determine sorption kinetics and sorption isotherms for the major nutrients Ca, Mg, K, NH4 and NO3 as a function of biochar types in different soil substrates (sand, loess). In addition, the biochars were washed to create free binding sites on the chars' surface that simulate aged char. We compared the simulated aged char with biochars that was aged in-situ at a field experiment for seven months. The first results showed that pyrochars have the largest retention potential for NO3 and hydrochars have retention potential for NH4. Washing of biochars turned them from a PO4 and NH4 source into an adsorber, especially for hydrochars. Highest leaching was observed for biochars from digestates likely due to the high nutrient content of digestates. But the different ions may lead to pH-dependent interactions between each other and the chars' surface that override the adsoption effects. In this context, cation-bridge and ligand bindings 4,5] need to be further investigated. Most of the fresh, unwashed biochars were a source of nutrients with hardly any detectable nutrient retention. Pyrochars showed the highest potential for anion

  15. [Effects of farmland use type and winter irrigation on nitrate accumulation in sandy farmland soil].

    PubMed

    Yang, Rong; Su, Yong-zhong

    2009-03-01

    With the sandy farmland in the marginal oasis in middle reaches of Heihe River Basin, Northwest China as test object, this paper studied soil NO3- -N accumulation and leaching under effects of different farmland use type and winter irrigation. The results showed that the mean NO3- -N concentration in 0-300 cm soil profile in different farmlands ranged from 1.27 mg x kg(-1) to 83.60 mg x kg(-1) Soil NO3- -N concentration was higher in 0-40 cm and 135-300 cm layers, but lower in 40-135 cm layer. Greenhouse vegetable field had a significantly higher soil NO3- -N concentration than the other farmland use types. The accumulated amount of soil NO3- -N decreased in the order of greenhouse vegetable field > tomato field > cotton field > seed maize field > maize-wheat rotation field > maize-wheat stripe intercropping field > alfalfa field > jujube plantation. The NO3- -N accumulation in 0-300 cm soil profile in greenhouse vegetable filed reached 2171.45 kg x hm(-2), which would be a serious menace to groundwater quality, followed by tomato field and cotton field. Lesser accumulation of soil NO3- -N was found in seed maize field, maize-wheat intercropping field, maize-wheat rotation field, alfalfa field, and jujube plantation, but its pollution potential would not be neglected. After winter irrigation, soil NO3- -N concentration decreased in 0-80 cm layer but increased in 80-300 cm layer, indicating that winter irrigation caused NO3- -N leaching into deeper soil depth. The leached amount of soil NO3- -N to deeper layers increased with increasing amount of winter irrigation. To mitigate soil NO3- -N leaching and groundwater contamination, a comprehensive consideration should be made on the rational arrangement of farmland use type, proper decrease of planting N-accumulated crops, and reasonable winter irrigation.

  16. Degradation pathway and field-scale DT50 determination of Boscalid in a sandy Soil

    NASA Astrophysics Data System (ADS)

    Karlsson, Anneli S.; Weihermüller, Lutz; Tappe, Wolfgang; Mukherjee, Santanu; Spielvogel, Sandra

    2016-04-01

    The research on environmental fate of pesticides has received increasing attention within the last decades and the persistence of several compounds in soil matrices is well documented. However, the fate of the new fungicide Boscalid (introduced in 2003) is not yet completely investigated. The aim of this study was to analyze the environmental fate of Boscalid in a sandy soil. Three years after the second application on a cropland site in Kaldenkirchen, Germany, 65 undisturbed soil samples from the plough layer were derived. Boscalid residues were extracted using Accelerated Solvent Extraction (ASE) and measured with UPLC-MS/MS. The Boscalid residues ranged between 0.12 and 0.53 μg kg-1with a field mean of 0.20 ± 0.09 μg kg-1. These results differed considerably from the predicted field concentration of 16.89 μg kg-1 (calculated from the application rate) and half-lives (DT50) of 104-182 days compared to 345 days reported in literature. Adjusting the extraction efficiency to 20% could not explain the large difference. Therefore, an incubation study with 14C-labeled Boscalid was conducted to measure the DT50 under controlled conditions. Here, the DT50 values were in the range of values stated in literature (297-337 days compared to 345 days) but still much larger than the DT50 based on the field-study values (104-182 days). Our results indicate that Boscalid dissipation under field conditions is much faster at agricultural sites with sandy soil type as expected from laboratory incubation experiments. Future experiments with Boscalid will be conducted in two different soils with different particle size. A laboratory experiment with uniformly 13C-labeled Boscalid will provide insight into the uptake and incorporation in microbial biomass.

  17. Degradation pathway and field-scale DT50 determination of Boscalid in a sandy Soil

    NASA Astrophysics Data System (ADS)

    Karlsson, Anneli S.; Weihermüller, Lutz; Tappe, Wolfgang; Mukherjee, Santanu; Spielvogel, Sandra

    2016-04-01

    The research on environmental fate of pesticides has received increasing attention within the last decades and the persistence of several compounds in soil matrices is well documented. However, the fate of the new fungicide Boscalid (introduced in 2003) is not yet completely investigated. The aim of this study was to analyze the environmental fate of Boscalid in a sandy soil. Three years after the second application on a cropland site in Kaldenkirchen, Germany, 65 undisturbed soil samples from the plough layer were derived. Boscalid residues were extracted using Accelerated Solvent Extraction (ASE) and measured with UPLC-MS/MS. The Boscalid residues ranged between 0.12 and 0.53 μg kg‑1with a field mean of 0.20 ± 0.09 μg kg‑1. These results differed considerably from the predicted field concentration of 16.89 μg kg‑1 (calculated from the application rate) and half-lives (DT50) of 104-182 days compared to 345 days reported in literature. Adjusting the extraction efficiency to 20% could not explain the large difference. Therefore, an incubation study with 14C-labeled Boscalid was conducted to measure the DT50 under controlled conditions. Here, the DT50 values were in the range of values stated in literature (297-337 days compared to 345 days) but still much larger than the DT50 based on the field-study values (104-182 days). Our results indicate that Boscalid dissipation under field conditions is much faster at agricultural sites with sandy soil type as expected from laboratory incubation experiments. Future experiments with Boscalid will be conducted in two different soils with different particle size. A laboratory experiment with uniformly 13C-labeled Boscalid will provide insight into the uptake and incorporation in microbial biomass.

  18. Biochar reduces copper toxicity in Chenopodium quinoa Willd. In a sandy soil.

    PubMed

    Buss, Wolfram; Kammann, Claudia; Koyro, Hans-Werner

    2012-01-01

    Mining, smelting, land applications of sewage sludge, the use of fungicides containing copper (Cu), and other human activities have led to widespread soil enrichment and contamination with Cu and potentially toxic conditions. Biochar (BC) can adsorb several substances, ranging from herbicides to plant-inhibiting allelochemicals. However, the range of potential beneficial effects on early-stage plant growth with regard to heavy metal toxicity is largely unexplored. We investigated the ameliorating properties of a forestry-residue BC under Cu toxicity conditions on early plant growth. Young quinoa plants () were grown in the greenhouse in the presence of 0, 2, and 4% BC application (w/w) added to a sandy soil with 0, 50, or 200 μg g Cu supplied. The plants without BC showed severe stress symptoms and reduced growth shortly after Cu application of 50 μg g and died at 200 μg Cu g. Increasing BC concentrations in the growth medium significantly increased the plant performance without Cu toxicity or under Cu stress. At the 4% BC application rate, the plants with 200 μg g Cu almost reached the same biomass as in the control treatment. In the presence of BC, less Cu entered the plant tissues, which had reduced Cu concentrations in the order roots, shoots, leaves. The amelioration effect also was reflected in the plant-soil system CO gas exchange, which showed clear signs of improvement with BC presence. The most likely ameliorating mechanisms were adsorption of Cu to negatively charged BC surfaces and an improvement of the water supply. Overall, BC seems to be a beneficial amendment with the potential to ameliorate Cu toxicity in sandy soils. Further research with a broad spectrum of different soil types, BCs, and crop plants is required.

  19. Reactive transport controls on sandy acid sulfate soils and impacts on shallow groundwater quality

    NASA Astrophysics Data System (ADS)

    Salmon, S. Ursula; Rate, Andrew W.; Rengel, Zed; Appleyard, Steven; Prommer, Henning; Hinz, Christoph

    2014-06-01

    Disturbance or drainage of potential acid sulfate soils (PASS) can result in the release of acidity and degradation of infrastructure, water resources, and the environment. Soil processes affecting shallow groundwater quality have been investigated using a numerical code that integrates (bio)geochemical processes with water, solute, and gas transport. The patterns of severe and persistent acidification (pH < 4) in the sandy, carbonate-depleted podzols of a coastal plain could be reproduced without calibration, based on oxidation of microcrystalline pyrite after groundwater level decrease and/or residual groundwater acidity, due to slow vertical solute transport rates. The rate of acidification was limited by gas phase diffusion of oxygen and hence was sensitive to soil water retention properties and in some cases also to oxygen consumption by organic matter mineralization. Despite diffusion limitation, the rate of oxidation in sandy soils was rapid once pyrite-bearing horizons were exposed, even to a depth of 7.5 m. Groundwater level movement was thus identified as an important control on acidification, as well as the initial pyrite content. Increase in the rate of Fe(II) oxidation lead to slightly lower pH and greater accumulation of Fe(III) phases, but had little effect on the overall amount of pyrite oxidized. Aluminosilicate (kaolinite) dissolution had a small pH-buffering effect but lead to the release of Al and associated acidity. Simulated dewatering scenarios highlighted the potential of the model for risk assessment of (bio)geochemical impacts on soil and groundwater over a range of temporal and spatial scales.

  20. Aerobic biodegradation of propylene glycol by soil bacteria.

    PubMed

    Toscano, Giuseppe; Cavalca, Lucia; Letizia Colarieti, M; Scelza, Rosalia; Scotti, Riccardo; Rao, Maria A; Andreoni, Vincenza; Ciccazzo, Sonia; Greco, Guido

    2013-09-01

    Propylene glycol (PG) is a main component of aircraft deicing fluids and its extensive use in Northern airports is a source of soil and groundwater contamination. Bacterial consortia able to grow on PG as sole carbon and energy source were selected from soil samples taken along the runways of Oslo Airport Gardermoen site (Norway). DGGE analysis of enrichment cultures showed that PG-degrading populations were mainly composed by Pseudomonas species, although Bacteroidetes were found, as well. Nineteen bacterial strains, able to grow on PG as sole carbon and energy source, were isolated and identified as different Pseudomonas species. Maximum specific growth rate of mixed cultures in the absence of nutrient limitation was 0.014 h(-1) at 4 °C. Substrate C:N:P molar ratios calculated on the basis of measured growth yields are in good agreement with the suggested values for biostimulation reported in literature. Therefore, the addition of nutrients is suggested as a suitable technique to sustain PG aerobic degradation at the maximum rate by autochthonous microorganisms of unsaturated soil profile.

  1. Phytotoxicity of nitroaromatic energetic compounds freshly amended or weathered and aged in sandy loam soil.

    PubMed

    Rocheleau, Sylvie; Kuperman, Roman G; Martel, Majorie; Paquet, Louise; Bardai, Ghalib; Wong, Stephen; Sarrazin, Manon; Dodard, Sabine; Gong, Ping; Hawari, Jalal; Checkai, Ronald T; Sunahara, Geoffrey I

    2006-01-01

    The toxicities of 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitrobenzene (TNB), 2,4-dinitrotoluene (2,4-DNT), and 2,6-dinitrotoluene (2,6-DNT) to terrestrial plants alfalfa (Medicago sativa L.), Japanese millet (Echinochloa crusgalli L.), and perennial ryegrass (Lolium perenne L.) were determined in Sassafras sandy loam soil using seedling emergence, fresh shoot, and dry mass measurement endpoints. A 13-week weathering and aging of energetic materials in soils, which included wetting and drying cycles, and exposure to sunlight of individual soil treatments, was incorporated into the study design to better reflect the soil exposure conditions in the field than toxicity determinations in freshly amended soils. Definitive toxicity tests showed that dinitrotoluenes were more phytotoxic for all plant species in freshly amended treatments based on EC20 values for dry shoot ranging from 3 to 24mgkg(-1) compared with values for TNB or TNT ranging from 43 to 62mgkg(-1). Weathering and aging of energetic materials (EMs) in soil significantly decreased the toxicity of TNT, TNB or 2,6-DNT to Japanese millet or ryegrass based on seedling emergence, but significantly increased the toxicity of all four EMs to all three plant species based on shoot growth. Exposure of the three plant species to relatively low concentrations of the four compounds initially stimulated plant growth before the onset of inhibition at greater concentrations (hormesis).

  2. Leaching losses of two nutrients and an herbicide from two sandy soils during transient drainage

    SciTech Connect

    Mansell, R.S.; Wheeler, W.B.; Calvert, D.W.

    1980-09-01

    Shallow-tilled (ST) and deep-tilled (DT) plots of an acid, sandy soil were used to measure changes in potassium, nitrogen nitrates, and Terbacil concentrations in subsurface drainage water from the plots. Fertilizer and Terbacil herbicide was applied to the soil. Transient water flow was applied to the plots for a 2-wk period after 7.6 cm of irrigation had been achieved. Drainage water contained higher concentrations of all solutes than did DT drainage water. In the DT soil, the discharges of potassium, nitrogen producing nitrates, and terbacil were only 29.6, 37.0, and 13.9% respectively as large as those in the ST soil. Total cumulative drainage from DT soil was only 51.1% that from ST soil. Thus, relatively small quantities of irrigation and rainfall produced relatively large nutrient discharges. As irrigation was begun soon after fertilizer application, the leaching loss of these solutes would be expected to be greater than if water application had occurred later. 13 references, 8 figures, 5 tables.

  3. Immobilization of arsenate in a sandy loam soil using starch-stabilized magnetite nanoparticles.

    PubMed

    Liang, Qiqi; Zhao, Dongye

    2014-04-30

    This study investigated effectiveness of starch-stabilized magnetite nanoparticles for in situ enhanced sorption and immobilization of arsenate, As(V), in a model sandy loam soil. Batch tests showed that the nanoparticles offered an As(V) distribution coefficient of 10,000 L/g, which is >3 orders of magnitude greater than that for the soil. Batch and column experimental results revealed that the nanoparticle treatment greatly reduced water-leachable As(V) and the leachability of As(V) remaining in the soil per TCLP (Toxicity Characteristic Leaching Procedure) analysis. Column tests showed that water-leachable As(V) from the As(V)-laden soil containing 31.45 mg/kg was reduced by ∼93% and the TCLP leachability by >83% when the soil was treated with 34 pore volumes of a 0.1g-Fe/L of the nanoparticle suspension. While the nanoparticles are deliverable in the soil, the effective travel distance of the nanoparticles can be manipulated by controlling the injection flow rate. Under natural groundwater flow conditions (velocity ≤ 2.4 × 10(-4)cm/s), the delivered nanoparticles are confined within a limited distance (<6.1cm).

  4. Hydrophobicity in sandy soils triggered by the development of Scots Pine stands in southern Brandenburg, Germany

    NASA Astrophysics Data System (ADS)

    Spröte, Roland; Fischer, Thomas; Veste, Maik; Lange, Philipp; Bens, Oliver; Raab, Thomas; Hüttl, Reinhard F.

    2010-05-01

    Soil hydrophobicity is wide-spread in forest soils and many other ecosystems and has important hydrological consequences. Therefore, the development of water repellency is an important controlling factor for hydrological processes, preventing infiltration of precipitation and has large implication for the entire ecosystem functioning. It depends e. g. on plant species, age and season of the year. The phenomenon is defined as a situation during which the cohesive forces of water molecules are stronger than the adhesive forces between the water molecules in the soil, resulting in a high contact angle of water with the surface. Scots Pine is the predominant forest tree on the sandy soils in southern Brandenburg, Germany. Previous studies proved that the development of hydrophobicity on sandy soils in Brandenburg is triggered by Scots Pine (Pinus sylvestris). Investigations of the development of hydrophobicity and their initialisation are rare. Objective of our study was to characterise the initialisation of hydrophobicity and its implication for hydrological processes in the initial phase of ecosystem development. The occurrence of water repellency can be an important abiotic factor for the ecosystem development. We investigated the development of hydrophobicity under Scots Pines of four different age classes (young, juvenescent, mature, old) at Groß Oßnig (approx. 20 km south of Cottbus, Germany, mean annual rainfall approx. 559 mm, mean annual temperature 9.3° C). The study site is characterised by sandy soils with pure Scots Pine forest. Due to former military activities initial stages of ecosystem development with open areas can be found in the landscape. As a pioneer tree species Pinus sylvestris re-colonizes such open spaces. Under juvenescent trees no soil horizons were recognizable. With increasing tree height needles accumulated under the trees and a thicker litter layer has developed. The ´actuaĺ water repellency was determined in situ with the water

  5. Leaching and ponding of viral contaminants following land application of biosolids on sandy-loam soil.

    PubMed

    Wong, Kelvin; Harrigan, Tim; Xagoraraki, Irene

    2012-12-15

    Much of the land available for application of biosolids is cropland near urban areas. Biosolids are often applied on hay or grassland during the growing season or on corn ground before planting or after harvest in the fall. In this study, mesophilic anaerobic digested (MAD) biosolids were applied at 56,000 L/ha on a sandy-loam soil over large containment lysimeters seeded to perennial covers of orchardgrass (Dactylis glomerata L.), switchgrass (Panicum virgatum), or planted annually to maize (Zea mays L.). Portable rainfall simulators were to maintain the lysimeters under a nearly saturated (90%, volumetric basis) conditions. Lysimeter leachate and surface ponded water samples were collected and analyzed for somatic phage, adenoviruses, and anionic (chloride) and microbial (P-22 bacteriophage) tracers. Neither adenovirus nor somatic phage was recovered from the leachate samples. P-22 bacteriophage was found in the leachate of three lysimeters (removal rates ranged from 1.8 to 3.2 log(10)/m). Although the peak of the anionic tracer breakthrough occurred at a similar pore volume in each lysimeter (around 0.3 pore volume) the peak of P-22 breakthrough varied between lysimeters (<0.1, 0.3 and 0.7 pore volume). The early time to peak breakthrough of anionic and microbial tracers indicated preferential flow paths, presumably from soil cracks, root channels, worm holes or other natural phenomena. The concentration of viral contaminants collected in ponded surface water ranged from 1 to 10% of the initial concentration in the applied biosolids. The die off of somatic phage and P-22 in the surface water was fit to a first order decay model and somatic phage reached background level at about day ten. In conclusion, sandy-loam soils can effectively remove/adsorb the indigenous viruses leached from the land-applied biosolids, but there is a potential of viral pollution from runoff following significant rainfall events when biosolids remain on the soil surface. PMID:22885066

  6. Transport of simazine in unsaturated sandy soil and predictions of its leaching under hypothetical field conditions.

    PubMed

    Suárez, Francisco; Bachmann, Jaime; Muñoz, José F; Ortiz, Cristian; Tyler, Scott W; Alister, Claudio; Kogan, Marcelo

    2007-12-01

    The potential contamination of groundwater by herbicides is often controlled by processes in the vadose zone, through which herbicides travel before entering groundwater. In the vadose zone, both physical and chemical processes affect the fate and transport of herbicides, therefore it is important to represent these processes by mathematical models to predict contaminant movement. To simulate the movement of simazine, a herbicide commonly used in Chilean vineyards, batch and miscible displacement column experiments were performed on a disturbed sandy soil to quantify the primary parameters and processes of simazine transport. Chloride (Cl(-)) was used as a non-reactive tracer, and simazine as the reactive tracer. The Hydrus-1D model was used to estimate the parameters by inversion from the breakthrough curves of the columns and to evaluate the potential groundwater contamination in a sandy soil from the Casablanca Valley, Chile. The two-site, chemical non-equilibrium model was observed to best represent the experimental results of the miscible displacement experiments in laboratory soil columns. Predictions of transport under hypothetical field conditions using the same soil from the column experiments were made for 40 years by applying herbicide during the first 20 years, and then halting the application and considering different rates of groundwater recharge. For recharge rates smaller than 84 mm year(-1), the predicted concentration of simazine at a depth of 1 m is below the U.S. EPA's maximum contaminant levels (4 microg L(-1)). After eight years of application at a groundwater recharge rate of 180 mm year(-1) (approximately 50% of the annual rainfall), simazine was found to reach the groundwater (located at 1 m depth) at a higher concentration (more than 40 microg L(-1)) than the existing guidelines in the USA and Europe.

  7. Temporal stability of the apparent electrical conductivity measured in seasonally dry sandy soil

    NASA Astrophysics Data System (ADS)

    Pedrera, Aura; Brevik, Eric C.; Giráldez, Juan V.; Vanderlinden, Karl

    2016-04-01

    Soil is spatially heterogeneous due to differences in parent material, climate, topography, time and management practices. The use of non-invasive and non-contact geophysical methods facilitates the exploration of natural landscapes or cropped areas. Electromagnetic induction (EMI) sensors which measure the soil apparent electrical conductivity (ECa) express soil spatial variability in terms of spatial soil ECa variability. In an agricultural context, knowledge and understanding of the soil spatial variability will allow us to delimit areas where precision agriculture techniques could be used to improve management practices. These practices enhance soil and water conservation, especially for sandy soils in Mediterranean climates where soils are dry for substantial periods of time. The first objective of this work was to apply principal component analysis (PCA) to see if a temporally stable component could be found. The second objective was to see if temporal stability information acquired from several ECa surveys could be used to better interpret results of a single survey in terms of relationships between ECa and soil water content (SWC). The experimental catchment, "La Manga", is located in SW Spain and covers 6.7 ha of a rainfed olive orchard. Soil profile samples were collected at 41 locations on a pseudo-regular grid. Samples were analyzed in the laboratory for soil texture, stone content, and bulk density (ρb). The catchment was sampled for gravimetric SWC at the 0-0.1 and 0.1-0.2 m depth intervals at the same 41 locations on 18 occasions. At the same 41 locations ECa was measured during 9 of the 18 SWC surveys using a DUALEM-21S EMI sensor. In addition, 7 field-wide ECa surveys were conducted. Soil ECa values were used to delimit three areas in the orchard, based on the spatial distribution of the first principal component (PC), which represented the spatial ECa pattern. Soil properties were studied within each area, and using analysis of variance

  8. [Soil sandy desertification and salinization and their interrelationships in Yanghuang irrigated area of Hongsipu, Ningxia of northwest China].

    PubMed

    Yang, Xin-guo; Song, Nai-ping

    2011-09-01

    By the methods of controlled and typical sampling, this paper analyzed the texture, salinization characteristics, cation exchange capacity (CEC), and their correlations in the 0-40 cm soil profiles of corn land, medlar land, and non-utilized land in Yanghuang irrigated area of Hongsipu, Northwest China. Under controlled sampling, the salt content in the soil profiles was 0.69-1.30 g x kg(-1) (except in non-utilized land where the 0-10 cm soil salt content was up to 1.74 g x kg(-1)), with no obvious salinization. The sodium adsorption ratio and exchangeable sodium percentage in the 20-40 cm soil layer of medlar land were 12.18 and 14.1%, respectively, and the total content of clay and silt in the 0-40 cm soil profile of medlar land was up to 37.3% whereas that in the 0-20 cm soil layer of corn land was only 13.5%. In the 20-40 cm soil layer of corn land, the indices of sandy desertification and salinization had significant correlations under controlled sampling but no correlations under typical sampling, while the CEC and the sandy desertification and salinization indices had significant correlations under typical sampling. In different land use types in the study area, soil sandy desertification and salinization had complicated interrelationships, and CEC could be used as the indicator for the changes in soil environmental quality.

  9. Fate of CL-20 in sandy soils: degradation products as potential markers of natural attenuation.

    PubMed

    Monteil-Rivera, Fanny; Halasz, Annamaria; Manno, Dominic; Kuperman, Roman G; Thiboutot, Sonia; Ampleman, Guy; Hawari, Jalal

    2009-01-01

    Hexanitrohexaazaisowurtzitane (CL-20) is an emerging explosive that may replace the currently used explosives such as RDX and HMX, but little is known about its fate in soil. The present study was conducted to determine degradation products of CL-20 in two sandy soils under abiotic and biotic anaerobic conditions. Biotic degradation was prevalent in the slightly acidic VT soil, which contained a greater organic C content, while the slightly alkaline SAC soil favored hydrolysis. CL-20 degradation was accompanied by the formation of formate, glyoxal, nitrite, ammonium, and nitrous oxide. Biotic degradation of CL-20 occurred through the formation of its denitrohydrogenated derivative (m/z 393 Da) while hydrolysis occurred through the formation of a ring cleavage product (m/z 156 Da) that was tentatively identified as CH(2)=N-C(=N-NO(2))-CH=N-CHO or its isomer N(NO(2))=CH-CH=N-CO-CH=NH. Due to their chemical specificity, these two intermediates may be considered as markers of in situ attenuation of CL-20 in soil.

  10. Fate of CL-20 in sandy soils: degradation products as potential markers of natural attenuation.

    PubMed

    Monteil-Rivera, Fanny; Halasz, Annamaria; Manno, Dominic; Kuperman, Roman G; Thiboutot, Sonia; Ampleman, Guy; Hawari, Jalal

    2009-01-01

    Hexanitrohexaazaisowurtzitane (CL-20) is an emerging explosive that may replace the currently used explosives such as RDX and HMX, but little is known about its fate in soil. The present study was conducted to determine degradation products of CL-20 in two sandy soils under abiotic and biotic anaerobic conditions. Biotic degradation was prevalent in the slightly acidic VT soil, which contained a greater organic C content, while the slightly alkaline SAC soil favored hydrolysis. CL-20 degradation was accompanied by the formation of formate, glyoxal, nitrite, ammonium, and nitrous oxide. Biotic degradation of CL-20 occurred through the formation of its denitrohydrogenated derivative (m/z 393 Da) while hydrolysis occurred through the formation of a ring cleavage product (m/z 156 Da) that was tentatively identified as CH(2)=N-C(=N-NO(2))-CH=N-CHO or its isomer N(NO(2))=CH-CH=N-CO-CH=NH. Due to their chemical specificity, these two intermediates may be considered as markers of in situ attenuation of CL-20 in soil. PMID:18801604

  11. Characterization of vegetation and soils of rehabilitated sandy wastelands at the Usinsk oilfields (the Komi Republic)

    NASA Astrophysics Data System (ADS)

    Likhanova, I. A.; Khabibullina, F. M.; Kurakov, A. V.

    2008-09-01

    The soils and phytocenoses developed over 13 years after four procedures of rehabilitation of sandy wastelands in the area of Usinsk oilfields (the northernmost taiga) are characterized. The planting of pine seedlings and especially the sowing of perennial grasses, along with the improvement of the substrate by application of peat and fertilizers, were the most efficient rehabilitation technologies as compared to the planting of only willow cuttings or 7-to 19-year-old pine wildings. On the plots where grasses were sown and pine seedlings were planted, the plant communities were at the preclimax succession stage (small-leaved tree species and shrubs) before the regeneration of the coniferous forest. The input of abundant plant residues have led to the formation of weakly developed soils with higher contents of organic carbon and hydrolyzable nitrogen as compared to their concentrations in the initial substrate. However, they were much lower as compared with the reference peaty-podzolic iron-illuvial soil. In the upper horizons of the weakly developed soils, the number of colony-forming units of bacteria and fungi and the mycobiota diversity were close to those in the reference soil, but the activity of the microbiological processes remained substantially lower in these horizons.

  12. Manure Refinement Affects Apple Rhizosphere Bacterial Community Structure: A Study in Sandy Soil

    PubMed Central

    Zhang, Qiang; Sun, Jian; Liu, Songzhong; Wei, Qinping

    2013-01-01

    We used DNA-based pyrosequencing to characterize the bacterial community structure of the sandy soil of an apple orchard with different manure ratios. Five manure percentages (5%, 10%, 15%, 20% and 25%) were examined. More than 10,000 valid reads were obtained for each replicate. The communities were composed of five dominant groups (Proteobacteria, Actinobacteria, Chloroflexi, Acidobacteria and Bacteroidetes), of which Proteobacteria content gradually decreased from 41.38% to 37.29% as manure ratio increased from 0% to 25%, respectively. Redundancy analysis showed that 37 classes were highly correlated with manure ratio, 18 of which were positively correlated. Clustering revealed that the rhizosphere samples were grouped into three components: low manure (control, 5%) treatment, medium manure (10%, 15%) treatment and high manure (20%, 25%) treatment. Venn analysis of species types of these three groups revealed that the bacteria community difference was primarily reflected by quantity ratio rather than species variety. Although greater manure content led to higher soil organic matter content, the medium manure improved soil showed the highest urease activity and saccharase activity, while 5% to 20% manure ratio improvement also resulted in higher bacteria diversity than control and 25% manure ratio treatment. Our experimental results suggest that the use of a proper manure ratio results in significantly higher soil enzyme activity and different bacteria community patterns, whereas the use of excessive manure amounts has negative effect on soil quality. PMID:24155909

  13. Application of bimetallic iron (BioCAT slurry) for pentachlorophenol removal from sandy soil.

    PubMed

    Dien, Nguyen Thanh; De Windt, Wim; Buekens, Alfons; Chang, Moo Been

    2013-05-15

    Bimetallic iron nanoparticles have mostly been applied to the degradation of chlorinated compounds in the aqueous phase. In this study, the degradation of pentachlorophenol (PCP) spiked into sandy soil is considered as a first exploratory step for remediating PCP in real contaminated soil using a commercial preparation of bimetallic iron (Trade name BioCAT). After 21 days of treatment a PCP removal efficiency of 90% was achieved, along with 70% dechlorination efficiency, for a dosage of 600 mg BioCAT slurry/kg soil. Degradation of PCP by BioCAT follows first order kinetics in PCP. Stepwise dechlorination is the main pathway of PCP elimination from soil slurries contacted with BioCAT. Such dechlorination is confirmed by the appearance of intermediate products, as well as by release of chlorides. Additionally, the increasing pH value and the rapid decrease of the oxidation/reduction potential (ORP) also attest to the reductive dechlorination of PCP. The reaction products comprehend lower chlorinated phenols, including three TeCP isomers, four TrCP isomers, four DCP isomers, two MCP isomers and phenol. These findings indicate that BioCAT could be applied for field treatment of PCP-contaminated soil under ambient conditions.

  14. Manure refinement affects apple rhizosphere bacterial community structure: a study in sandy soil.

    PubMed

    Zhang, Qiang; Sun, Jian; Liu, Songzhong; Wei, Qinping

    2013-01-01

    We used DNA-based pyrosequencing to characterize the bacterial community structure of the sandy soil of an apple orchard with different manure ratios. Five manure percentages (5%, 10%, 15%, 20% and 25%) were examined. More than 10,000 valid reads were obtained for each replicate. The communities were composed of five dominant groups (Proteobacteria, Actinobacteria, Chloroflexi, Acidobacteria and Bacteroidetes), of which Proteobacteria content gradually decreased from 41.38% to 37.29% as manure ratio increased from 0% to 25%, respectively. Redundancy analysis showed that 37 classes were highly correlated with manure ratio, 18 of which were positively correlated. Clustering revealed that the rhizosphere samples were grouped into three components: low manure (control, 5%) treatment, medium manure (10%, 15%) treatment and high manure (20%, 25%) treatment. Venn analysis of species types of these three groups revealed that the bacteria community difference was primarily reflected by quantity ratio rather than species variety. Although greater manure content led to higher soil organic matter content, the medium manure improved soil showed the highest urease activity and saccharase activity, while 5% to 20% manure ratio improvement also resulted in higher bacteria diversity than control and 25% manure ratio treatment. Our experimental results suggest that the use of a proper manure ratio results in significantly higher soil enzyme activity and different bacteria community patterns, whereas the use of excessive manure amounts has negative effect on soil quality.

  15. Numerical Analysis of coupled liquid water, water vapor and heat transport in a sandy loam soil

    NASA Astrophysics Data System (ADS)

    Shukla, M. K.; Deb, S.; Sharma, P.

    2009-12-01

    Water vapor transport could be significant in arid areas such as southern New Mexico. Temporal soil moisture variations in unsaturated soils due to temperature gradients are characterized by the water vapor transport in the surface soil layer as liquid water movement could be very small especially when surface soil moisture is low. Numerical model Hydrus-1D was applied to investigate non-isothermal liquid and vapor flow closely coupled with the heat transport in a furrow-irrigated onion field located at Leyendecker Plant Science Research Center, Las Cruces. TDR and temperature sensors were installed to continuously monitor diurnal soil moisture and temperature variations in sandy loam onion beds at 5, 10, 20, and 50 cm depths during the entire growing season. Meteorological data were obtained from PSRC weather station. Hydrus-1D simulated soil moisture and temperature favorably contrasted against measured data at different depths. Simulations indicated that both liquid and vapor fluxes contributed to the water transport near surface. Liquid flux dominated the water movement during an irrigation event, while contribution of vapor flux increased with increasing soil drying. Vapor flux decreased from 5 cm to 25 cm depth, indicating that water vapor flux is much higher in the layer near soil surface. Both diffusive and dispersive transports are responsible for the vapor flux in the near-surface dry zone, while convective liquid flux was the main transport mechanism in the near-surface wet lower zone. In near-surface wet zone, diffusive flux decreased and changed from upward to downward flux.

  16. Field scale boscalid residues and dissipation half-life estimation in a sandy soil.

    PubMed

    Karlsson, Anneli Sofia; Weihermüller, Lutz; Tappe, Wolfgang; Mukherjee, Santanu; Spielvogel, Sandra

    2016-02-01

    The aim of this study was to analyze the environmental fate of the fungicide boscalid in a sandy soil. Boscalid was applied in spring 2010/11 to a cropland site in western Germany. Three years after second application 65 undisturbed soil samples were taken. Boscalid was extracted using accelerated solvent extraction (ASE). Boscalid contents in the plough horizon ranged between 0.12 and 0.53 with a field mean of 0.20 ± 0.09 μg kg(-1). These contents were considerably lower compared to calculation using literature DT50 values, whereby a concentration of 16.89 μg kg(-1) was expected assuming a literature DT50 value of 345 days. Therefore, the measured field boscalid concentration only yields 1.2% of the expected value. To test whether the unknown extraction efficiency, losses from spray drift and interception can explain the mismatch between calculated and measured concentrations all these uncertainties were taken into account into calculations, but field concentrations and DT50 were still lower as expected. Leaching to deeper horizons was also studied but could not explain the discrepancy either. Moreover, a short-term incubation experiment using (14)C labelled boscalid revealed also shorter DT50 values of 297-337 compared to the 345 days taken from literature. However, this DT50 value is still considerably larger compared to the 104-224 days that were calculated based on the field experiment. Our results indicate that boscalid dissipation under field conditions is much faster at agricultural sites with sandy soil type as expected from laboratory incubation experiments. PMID:26688253

  17. Microbial bioavailability of pyrene in three laboratory-contaminated soils under aerobic and anaerobic conditions.

    PubMed

    Pravecek, Tasha L; Christman, Russell F; Pfaender, Frederic K

    2006-06-30

    Changes in bioavailability of pyrene in three uncontaminated soils were examined under aerobic and anaerobic conditions. Three soils were aerobically aged with pyrene and [(14)C]pyrene for 63 days, then incubated with water, nitrate, or sulfate under aerobic or anaerobic conditions for one year. Under aerobic conditions, microorganisms in two soils mineralized 58-82% of the added [(14)C]pyrene. The two soils amended with nitrate were seen to have enhanced aerobic mineralization rates. In one of these soils, non-extractable pyrene was seen to decrease over the course of the study due to desorption and mineralization, nitrate amendment enhanced this effect. Under anaerobic conditions, generated with a N(2):CO(2)(g) headspace, two soils with nitrate or sulfate amendment showed an increase in extractable [(14)C]pyrene at 365 days relative to inhibited controls, presumably due to microbially mediated oxidation-reduction potential and pH alteration of the soil environment. These observations in different soils incubated under aerobic and anaerobic conditions have important implications relative to the impact of microbial electron acceptors on bioavailability and transport of non-polar organic compounds in the environment suggesting that, given enough time, under the appropriate environmental conditions, non-extractable material becomes bioavailable. This information should be considered when assessing site specific exposure risks at PAH contaminated locations. PMID:16574273

  18. Chemical contamination of soils in the New York City area following Hurricane Sandy.

    PubMed

    Mandigo, Amy C; DiScenza, Dana J; Keimowitz, Alison R; Fitzgerald, Neil

    2016-10-01

    This paper presents a unique data set of lead, arsenic, polychlorinated biphenyl (PCB), and polycyclic aromatic hydrocarbon (PAH) concentrations in soil samples collected from the metropolitan New York City area in the aftermath of Hurricane Sandy. Initial samples were collected by citizen scientists recruited via social media, a relatively unusual approach for a sample collection project. Participants in the affected areas collected 63 usable samples from basements, gardens, roads, and beaches. Results indicate high levels of arsenic, lead, PCBs, and PAHs in an area approximately 800 feet south of the United States Environmental Protection Agency (US EPA) Superfund site at Newtown Creek. A location adjacent to the Gowanus Canal, another Superfund site, was found to have high PCB concentrations. Areas of high PAH contamination tended to be near high traffic areas or next to sites of known contamination. While contamination as a direct result of Hurricane Sandy cannot be demonstrated conclusively, the presence of high levels of contamination close to known contamination sites, evidence for co-contamination, and decrease in number of samples containing measureable amounts of semi-volatile compounds from samples collected at similar locations 9 months after the storm suggest that contaminated particles may have migrated to residential areas as a result of flooding.

  19. Effects of Maghnian bentonite on physical properties of sandy soils under semi-arid Mediterranean climate.

    PubMed

    Benkhelifa, M; Belkhodja, M; Daoud, Y; Tessier, D

    2008-01-01

    This research has for object to study the influence of clay addition, i.e., Maghnian bentonite, like deposit clay, in the physical properties of sandy materials from Mostaganem plateau (North-West Algeria) submitted to salinity and sodicity. The first result was to show that the clay content changes drastically the physical properties of clay-sand mixtures. Important differences were observed as a function of the sand particle size distribution. At given clay content, the saturated Hydraulic Conductivity (HCs) was lower when the sand size was small and spread. For the coarse sand the salinity was maintained, even for high clay contents, a significant hydraulic conductivity. One of the main characteristics of Maghnia clay is the presence of calcium carbonates in the natural material. In comparison to that of Mostaganem clay of other deposit, it appears less sensitive to sodicity. An important aspect is the initial state of the clay when used in addition to sands, i.e., disturbance, conditions of preparation of sand clay mixtures and presence of associated components such as carbonates. Maghnia clay appeared to be adapted to the improvement of sandy soils, not because its mineralogical characteristics, but for its natural cationic form and obviously the presence of calcite in it. PMID:18819588

  20. Chemical contamination of soils in the New York City area following Hurricane Sandy.

    PubMed

    Mandigo, Amy C; DiScenza, Dana J; Keimowitz, Alison R; Fitzgerald, Neil

    2016-10-01

    This paper presents a unique data set of lead, arsenic, polychlorinated biphenyl (PCB), and polycyclic aromatic hydrocarbon (PAH) concentrations in soil samples collected from the metropolitan New York City area in the aftermath of Hurricane Sandy. Initial samples were collected by citizen scientists recruited via social media, a relatively unusual approach for a sample collection project. Participants in the affected areas collected 63 usable samples from basements, gardens, roads, and beaches. Results indicate high levels of arsenic, lead, PCBs, and PAHs in an area approximately 800 feet south of the United States Environmental Protection Agency (US EPA) Superfund site at Newtown Creek. A location adjacent to the Gowanus Canal, another Superfund site, was found to have high PCB concentrations. Areas of high PAH contamination tended to be near high traffic areas or next to sites of known contamination. While contamination as a direct result of Hurricane Sandy cannot be demonstrated conclusively, the presence of high levels of contamination close to known contamination sites, evidence for co-contamination, and decrease in number of samples containing measureable amounts of semi-volatile compounds from samples collected at similar locations 9 months after the storm suggest that contaminated particles may have migrated to residential areas as a result of flooding. PMID:26486130

  1. Estimating unique soil hydraulic parameters for sandy media from multi-step outflow experiments

    NASA Astrophysics Data System (ADS)

    Il Hwang, Sang; Powers, Susan E.

    Estimating unique soil hydraulic parameters is required to provide input for numerical models simulating transient water flow in the vadose zone. In this paper, we analyze the capability of six soil hydraulic functions to provide unique parameter sets for sandy soils from multi-step outflow data. Initial parameter estimates and experimental boundary conditions were explored to determine their affect on the uniqueness of soil hydraulic functions. Of the hydraulic functions tested, the lognormal distribution-Mualem (LDM) function provided the best performance and a unique solution for error-free numerically generated multi-step outflow data. For experimental multi-step outflow data with inherent measurement errors, the LDM function again showed better performance and uniqueness than the van Genuchten-Mualem and Gardner-Mualem functions. In experiments with different boundary conditions, the LDM function provided the best fitting ability, resulting in unique parameter sets when the intrinsic permeability ( k) was fixed at its measured value. The experiment that had a greater number of pneumatic pressure steps, thereby causing a lower flow rate, provided better fitting ability and more unique solutions than faster experiments.

  2. Characterisation of phosphate solubilising bacteria in sandy loam soil under chickpea cropping system.

    PubMed

    Singh, Machiavelli; Tejo Prakash, N

    2012-06-01

    With the aim to explore the possible role of phosphate-solubilizing bacteria (PSB) in phosphorus (P) cycling in agricultural soils, we isolated PSB inhabiting naturally in the sandy loam soils under chickpea cropping of Patiala (Punjab State). A total of 31 bacterial isolates showing solubilizing activities were isolated on Pikovskaya agar plates. The potent phosphate solubilizers were selected for further characterization. These isolates were shown to belong to the genera Pseudomonas and Serratia by partial sequencing analysis of their respective 16S rDNA genes. ERIC-PCR based fingerprinting was done for tracking the survival of introduced populations of the PSB during mass inoculation of these strains under chickpea plots. The results showed positive correlation (r(2) = 0.853) among soil phosphatase activity and phosphate solubilizers population, which was also positively correlated (r(2) = 0.730) to available phosphorus. Identification and characterization of soil PSB for the effective plant growth-promotion broadens the spectrum of phosphate solubilizers available for field application. PMID:23729877

  3. Combating wind erosion of sandy soils and crop damage in the coastal deserts: Wind tunnel experiments

    NASA Astrophysics Data System (ADS)

    Genis, Arthur; Vulfson, Leonid; Ben-Asher, Jiftah

    2013-06-01

    In the western Negev desert of Israel frequent sandstorms cause heavy damage to young lettuce, carrot, peanut and potato plants during the planting season. The damage of plants is based mainly on the mechanical impact of saltating sand particles, which causes irreversible injuries to the plant leaves. Current agro-technique measures taken to prevent wind damage to crop in Israel are based on high frequency irrigation. Although the high-frequency irrigation helps bind soil particles together by forming a soil crust, it is associated with the large waste of water, which is not practical under the arid conditions. Application of polyacrylamide (PAM) as a chemical stabilizer has proved to be effective for prevention of soil erosion, saving irrigation water and a stable growth of plants in the early stages. Although the technique of PAM application is not yet used commercially in Israel, the preliminary studies suggested that it might have the potential to reduce the damage to the plant leaves by sandstorms, providing both environmental and agricultural benefits. In this study the effectiveness of PAM for preventing sandstorms in the western Negev was also investigated. Optimal concentration and volume of PAM solution per hectare of bare sandy soil were determined. For this purpose a wind tunnel was used to determine wind velocities of the first and continuous detachment of particles. The ability of PAM application to minimize the damage of plants by sandstorms was experimentally verified using image analysis tools.

  4. Wastewater effects on montmorillonite suspensions and hydraulic properties of sandy soils

    SciTech Connect

    Tarchitzky, J.; Golobati, Y.; Keren, R.; Chen, Y.

    1999-06-01

    Recycled wastewater effluent is an important source of irrigation water in arid and semiarid regions. In these regions, however, irrigation water quality is one of the main factors limiting plant growth. Wastewater effluents generally contain high concentrations of suspended and dissolved solids, both organic and inorganic. Inorganic dissolved solids are only minimally removed from the effluent during conventional sewage treatment. As a result, most of the salts added during domestic and industrial usage remain in the irrigation water and may eventually reach the soil. A number of researchers have reported reduced hydraulic conductivity for soils to which treated wastewater has been applied. In this research, the influence of dissolved organic matter (DOM) contained in reclaimed wastewater effluents on the flocculation of montmorillonite and on the hydraulic properties of soils was studied. Flocculation values (FVs) for Na-montmorillonite increased with increasing concentrations of DOM at all pH levels analyzed. Maximum FV levels were exhibited for Na-montmorillonite at the highest DOM concentrations. The effect of DOM on FV can be explained by the mechanisms of edge-charge reversal and mutual flocculation. The hydraulic conductivity (HC) of a sandy soil was determined in the laboratory by leaching columns with an electrolyte solution chemically similar to that of the wastewater effluent (but without DOM). In columns treated with wastewater effluent, the HC exhibited a sharp decrease to only 20% of its initial value. The adverse effect of DOM on HC was evident for this soil despite a relatively low exchangeable sodium percentage (ESP). The reduction in HC is likely to be the result of decreases soil pore-size, which reflects two processes: (1) retention of part of the DOM during water percolation; and (2) a change in pore-size distribution due to swelling and dispersion of clay particles. The latter may result from a higher percentage of adsorbed sodium combined

  5. Aerobic biotransformation of 2,4-dinitroanisole in soil and soil Bacillus sp.

    PubMed

    Perreault, Nancy N; Manno, Dominic; Halasz, Annamaria; Thiboutot, Sonia; Ampleman, Guy; Hawari, Jalal

    2012-04-01

    2,4-Dinitroanisole (DNAN) is a low sensitive melt-cast chemical being tested by the Military Industry as a replacement for 2,4,6-trinitrotoluene (TNT) in explosive formulations. Little is known about the fate of DNAN and its transformation products in the natural environment. Here we report aerobic biotransformation of DNAN in artificially contaminated soil microcosms. DNAN was completely transformed in 8 days in soil slurries supplemented with carbon and nitrogen sources. DNAN was completely transformed in 34 days in slurries supplemented with carbons alone and persisted in unamended microcosms. A strain of Bacillus (named 13G) that transformed DNAN by co-metabolism was isolated from the soil. HPLC and LC-MS analyses of cell-free and resting cell assays of Bacillus 13G with DNAN showed the formation of 2-amino-4-nitroanisole as the major end-product via the intermediary formation of the arylnitroso (ArNO) and arylhydroxylamino (ArNHOH) derivatives, indicating regioselective reduction of the ortho-nitro group. A series of secondary reactions involving ArNO and ArNHOH gave the corresponding azoxy- and azo-dimers. Acetylated and demethylated products were identified. Overall, this paper provides the evidence of fast DNAN transformation by the indigenous microbial populations of an amended soil with no history of contamination with explosives and a first insight into the aerobic metabolism of DNAN by the soil isolate Bacillus 13G.

  6. Copper Accumulation, Availability and Adsorption Capacity in Sandy Soils of Vineyards with Different Cultivation Duration

    NASA Astrophysics Data System (ADS)

    Mallmann, F. J. K.; Miotto, A.; Bender, M. A.; Gubiani, E.; Rheinheimer, D. D. S.; Kaminski, J.; Ceretta, C. A.; Šimůnek, J.

    2015-12-01

    Bordeaux mixture is a copper-based (Cu) fungicide and bactericide applied in vineyards to control plant diseases. Since it is applied several times per year, it accumulates in large quantities on plants and in soil. This study evaluates the Cu accumulation in, and desorption kinetics and adsorption capability of a sandy Ultisol in a natural field and in 3 vineyards for 5 (V1), 11 (V2), and 31 (V3) years in South of Brazil. Soil samples were collected in 8 depths (0-60 cm) of all four soil profiles, which all displayed similar soil properties. The following soil properties were measured: pH, organic matter (OM), soil bulk density, Cu total concentration, and Cu desorption and adsorption curves. A two first-order reactions model and the Langmuir isotherm were fitted to the desorption and adsorption curves, respectively. An increase in the total mass of Cu in the vineyards followed a linear regression curve, with an average annual increase of 7.15 kg ha-1. Cu accumulated down to a depth of 5, 20, and 30 cm in V1, V2 and V3, respectively, with the highest Cu content reaching 138.4 mg kg-1 in the 0-5 cm soil layer of V3. Cu desorption parameters showed a high correlation with its total concentration. Approximately 57 and 19% of total Cu were immediately and slowly available, respectively, indicating a high potential for plant absorption and/or downward movement. Cu concentrations extracted by EDTA from soil layers not affected by anthropogenic Cu inputs were very low. The maximum Cu adsorption capacity of the 0-5 and 5-10 cm soil layers increased with the vineyard age, reaching concentrations higher than 900 mg kg-1. This increase was highly related to OM and pH, which both increased with cultivation duration. Despite of low clay content of these soils, there is low risk of groundwater Cu contamination for actual conditions. However, high Cu concentrations in the surface layer of the long-term vineyards could cause toxicity problems for this and for companion crops.

  7. Controlled release fertilizer increased phytoremediation of petroleum-contaminated sandy soil.

    PubMed

    Cartmill, Andrew D; Cartmill, Donita L; Alarcón, Alejandro

    2014-01-01

    A greenhouse experiment was conducted to determine the effect of the application of controlled release fertilizer [(CRF) 0, 4,6, or 8 kg m(-3)] on Lolium multiflorum Lam. survival and potential biodegradation of petroleum hydrocarbons (0, 3000, 6000, or 15000 mg kg(-1)) in sandy soil. Plant adaptation, growth, photosynthesis, total chlorophyll, and proline content as well as rhizosphere microbial population (culturable heterotrophic fungal and bacterial populations) and total petroleum hydrocarbon (TPH)-degradation were determined. Petroleum induced-toxicity resulted in reduced plant growth, photosynthesis, and nutrient status. Plant adaptation, growth, photosynthesis, and chlorophyll content were enhanced by the application of CRF in contaminated soil. Proline content showed limited use as a physiological indicator of petroleum induced-stress in plants. Bacterial and filamentous fungi populations were stimulated by the petroleum concentrations. Bacterial populations were stimulated by CRF application. At low petroleum contamination, CRF did not enhance TPH-degradation. However, petroleum degradation in the rhizosphere was enhanced by the application of medium rates of CRF, especially when plants were exposed to intermediate and high petroleum contamination. Application of CRF allowed plants to overcome the growth impairment induced by the presence of petroleum hydrocarbons in soils. PMID:24912225

  8. Dissolved Organic Carbon Dynamics Along Terrestrial-aquatic Flowpaths in a Catchment Dominated by Sandy Soils

    NASA Astrophysics Data System (ADS)

    Wickland, K.; Walker, J. F.; Hood, K.; Butler, K. D.

    2015-12-01

    Aquatic systems receive significant amounts of terrestrially-derived dissolved organic carbon (DOC) from their watersheds. The amount and nature received depends on terrestrial carbon source strength, processing and losses of carbon during transport, and hydrologic connectivity between terrestrial and aquatic systems. While much research has been done on terrestrial DOC dynamics along terrestrial-aquatic flowpaths, there is still considerable uncertainty in many areas including the importance of different carbon sources, microbial metabolism and sorption of DOC, and processing of carbon in groundwater. Here we investigate DOC dynamics in soils, groundwater, and stream waters at the USGS Water, Energy, and Biogeochemical (WEBB) Program research site in northern Wisconsin. This site is well-suited for studying DOC dynamics as soils are sandy and homogenous with small DOC sorption potential, and previous work has characterized the hydrology of the region in detail. We collected water samples over two years from soil pit lysimeters along a series of hillslope transects, from shallow and deep groundwater wells, and from a first-order stream receiving these waters. We measured DOC concentration, DOC optical properties, and biodegradability of DOC. Combined with historical DOC and companion water chemistry data we characterize DOC generation and loss along the following flowpaths: 1) infiltration through the unsaturated zone to the groundwater table, 2) shallow groundwater flow, and 3) long groundwater flowpaths of different origin (lake-derived vs. terrestrial-derived water).

  9. Transport of E. coli in a sandy soil as impacted by depth to water table.

    PubMed

    Stall, Christopher; Amoozegar, Aziz; Lindbo, David; Graves, Alexandria; Rashash, Diana

    2014-01-01

    Septic systems are considered a source of groundwater contamination. In the study described in this article, the fate of microbes applied to a sandy loam soil from North Carolina coastal plain as impacted by water table depth was studied. Soil materials were packed to a depth of 65 cm in 17 columns (15-cm diameter), and a water table was established at 30, 45, and 60 cm depths using five replications. Each day, 200 mL of an artificial septic tank effluent inoculated with E. coli were applied to the top of each column, a 100-mL sample was collected at the water table level and analyzed for E. coli, and 100 mL was drained from the bottom to maintain the water table. Two columns were used as control and received 200 mL/day of sterilized effluent. Neither 30 nor 45 cm of unsaturated soil was adequate to attenuate bacterial contamination, while 60 cm of separation appeared to be sufficient. Little bacterial contamination moved with the water table when it was lowered from 30 to 60 cm.

  10. Percolation and transport in a sandy soil under a natural hydraulic gradient

    USGS Publications Warehouse

    Green, C.T.; Stonestrom, D.A.; Bekins, B.A.; Akstin, K.C.; Schulz, M.S.

    2005-01-01

    [1] Unsaturated flow and transport under a natural hydraulic gradient in a Mediterranean climate were investigated with a field tracer experiment combined with laboratory analyses and numerical modeling. Bromide was applied to the surface of a sandy soil during the dry season. During the subsequent rainy season, repeated sediment sampling tracked the movement of bromide through the profile. Analysis of data on moisture content, matric pressure, unsaturated hydraulic conductivity, bulk density, and soil texture and structure provides insights into parameterization and use of the advective-dispersive modeling approach. Capturing the gross features of tracer and moisture movement with model simulations required an order-of-magnitude increase in laboratory-measured hydraulic conductivity. Wetting curve characteristics better represented field results, calling into question the routine estimation of hydraulic characteristics based only on drying conditions. Measured increases in profile moisture exceeded cumulative precipitation in early winter, indicating that gains from dew drip can exceed losses from evapotranspiration during periods of heavy ("Tule") fog. A single-continuum advective-dispersive modeling approach could not reproduce a peak of bromide that was retained near the soil surface for over 3 years. Modeling of this feature required slow exchange of solute at a transfer rate of 0.5-1 ?? 10-4 d-1 with an immobile volume approaching the residual moisture content.

  11. Controlled release fertilizer increased phytoremediation of petroleum-contaminated sandy soil.

    PubMed

    Cartmill, Andrew D; Cartmill, Donita L; Alarcón, Alejandro

    2014-01-01

    A greenhouse experiment was conducted to determine the effect of the application of controlled release fertilizer [(CRF) 0, 4,6, or 8 kg m(-3)] on Lolium multiflorum Lam. survival and potential biodegradation of petroleum hydrocarbons (0, 3000, 6000, or 15000 mg kg(-1)) in sandy soil. Plant adaptation, growth, photosynthesis, total chlorophyll, and proline content as well as rhizosphere microbial population (culturable heterotrophic fungal and bacterial populations) and total petroleum hydrocarbon (TPH)-degradation were determined. Petroleum induced-toxicity resulted in reduced plant growth, photosynthesis, and nutrient status. Plant adaptation, growth, photosynthesis, and chlorophyll content were enhanced by the application of CRF in contaminated soil. Proline content showed limited use as a physiological indicator of petroleum induced-stress in plants. Bacterial and filamentous fungi populations were stimulated by the petroleum concentrations. Bacterial populations were stimulated by CRF application. At low petroleum contamination, CRF did not enhance TPH-degradation. However, petroleum degradation in the rhizosphere was enhanced by the application of medium rates of CRF, especially when plants were exposed to intermediate and high petroleum contamination. Application of CRF allowed plants to overcome the growth impairment induced by the presence of petroleum hydrocarbons in soils.

  12. Patterns and possible mechanisms of soil CO2 uptake in sandy soil.

    PubMed

    Fa, Ke-Yu; Zhang, Yu-Qing; Wu, Bin; Qin, Shu-Gao; Liu, Zhen; She, Wei-Wei

    2016-02-15

    It has been reported that soils in drylands can absorb CO2, although the patterns and mechanisms of such a process remain under debate. To address this, we investigated the relationships between soil CO2 flux and meteorological factors and soil properties in Northwest China to reveal the reasons for "anomalous" soil CO2 flux in a desert ecosystem. Soil CO2 flux increased significantly and exponentially with surficial turbulence at the diel scale under dry conditions (P<0.05), whereas the relationship under wet conditions was insignificant. Furthermore, soil CO2 flux demonstrated remarkable negative correlation with soil air pressure (P<0.05) in both dry and wet conditions. Analysis considering Henry's Law indicated that soil water content was insufficient to dissolve the absorbed CO2 in dry conditions, but was sufficient in wet conditions. The concentration of soil HCO3(-) in the morning was higher than in the evening in dry conditions, but this pattern was reversed in wet conditions. These results imply that CO2 outgassing induced by turbulence, expansion of soil air, CO2 effusion from soil water, and carbonate precipitation during daytime can explain the abiotic diurnal CO2 release. Moreover, CO2 pumping from the atmosphere into the soil, caused mainly by carbonate dissolution, can account for nocturnal CO2 absorption in dry conditions. The abiotic soil CO2 flux pattern (CO2 absorption throughout the diel cycle) in wet conditions can be attributed to downward mass flow of soil CO2 and intensified soil air shrinkage, CO2 dissolving in soil water, and carbonate dissolution. These results provide a basis for determining the location of abiotic fixed carbon within soils in desert ecosystems. PMID:26674687

  13. Patterns and possible mechanisms of soil CO2 uptake in sandy soil.

    PubMed

    Fa, Ke-Yu; Zhang, Yu-Qing; Wu, Bin; Qin, Shu-Gao; Liu, Zhen; She, Wei-Wei

    2016-02-15

    It has been reported that soils in drylands can absorb CO2, although the patterns and mechanisms of such a process remain under debate. To address this, we investigated the relationships between soil CO2 flux and meteorological factors and soil properties in Northwest China to reveal the reasons for "anomalous" soil CO2 flux in a desert ecosystem. Soil CO2 flux increased significantly and exponentially with surficial turbulence at the diel scale under dry conditions (P<0.05), whereas the relationship under wet conditions was insignificant. Furthermore, soil CO2 flux demonstrated remarkable negative correlation with soil air pressure (P<0.05) in both dry and wet conditions. Analysis considering Henry's Law indicated that soil water content was insufficient to dissolve the absorbed CO2 in dry conditions, but was sufficient in wet conditions. The concentration of soil HCO3(-) in the morning was higher than in the evening in dry conditions, but this pattern was reversed in wet conditions. These results imply that CO2 outgassing induced by turbulence, expansion of soil air, CO2 effusion from soil water, and carbonate precipitation during daytime can explain the abiotic diurnal CO2 release. Moreover, CO2 pumping from the atmosphere into the soil, caused mainly by carbonate dissolution, can account for nocturnal CO2 absorption in dry conditions. The abiotic soil CO2 flux pattern (CO2 absorption throughout the diel cycle) in wet conditions can be attributed to downward mass flow of soil CO2 and intensified soil air shrinkage, CO2 dissolving in soil water, and carbonate dissolution. These results provide a basis for determining the location of abiotic fixed carbon within soils in desert ecosystems.

  14. Soil metabolism of [14C]methiozolin under aerobic and anaerobic flooded conditions.

    PubMed

    Hwang, Ki-Hwan; Lim, Jong-Soo; Kim, Sung-Hun; Chang, Hee-Ra; Kim, Kyun; Koo, Suk-Jin; Kim, Jeong-Han

    2013-07-17

    Methiozolin is a new turf herbicide controlling annual bluegrass in various cool- and warm-season turfgrasses. This study was conducted to investigate the fate of methiozolin in soil under aerobic and anaerobic flooded conditions using two radiolabeled tracers, [benzyl-(14)C]- and [isoxazole-(14)C]methiozolin. The mass balance of applied radioactivity ranged from 91.7 to 104.5% in both soil conditions. In the soil under the aerobic condition, [(14)C]methiozolin degraded with time to remain by 17.9 and 15.9% of the applied in soil at 120 days after treatment (DAT). [(14)C]Carbon dioxide and the nonextractable radioactivity increased as the soil aged to reach up to 41.5 and 35.7% for [benzyl-(14)C]methiozolin at 120 DAT, respectively, but 36.1 and 39.8% for [isoxazole-(14)C]methiozolin, respectively, during the same period. The nonextractable residue was associated more with humin and fulvic acid fractions under the aerobic condition. No significant volatile products or metabolites were detected during this study. The half-life of [(14)C]methiozolin was approximately 49 days in the soil under the aerobic condition; however, it could not be estimated in the soil under the anaerobic flooded condition because [(14)C]methiozolin degradation was limited. On the basis of these results, methiozolin is considered to undergo fast degradation by aerobic microbes, but not by anaerobic microbes in soil. PMID:23772889

  15. Soil metabolism of [14C]methiozolin under aerobic and anaerobic flooded conditions.

    PubMed

    Hwang, Ki-Hwan; Lim, Jong-Soo; Kim, Sung-Hun; Chang, Hee-Ra; Kim, Kyun; Koo, Suk-Jin; Kim, Jeong-Han

    2013-07-17

    Methiozolin is a new turf herbicide controlling annual bluegrass in various cool- and warm-season turfgrasses. This study was conducted to investigate the fate of methiozolin in soil under aerobic and anaerobic flooded conditions using two radiolabeled tracers, [benzyl-(14)C]- and [isoxazole-(14)C]methiozolin. The mass balance of applied radioactivity ranged from 91.7 to 104.5% in both soil conditions. In the soil under the aerobic condition, [(14)C]methiozolin degraded with time to remain by 17.9 and 15.9% of the applied in soil at 120 days after treatment (DAT). [(14)C]Carbon dioxide and the nonextractable radioactivity increased as the soil aged to reach up to 41.5 and 35.7% for [benzyl-(14)C]methiozolin at 120 DAT, respectively, but 36.1 and 39.8% for [isoxazole-(14)C]methiozolin, respectively, during the same period. The nonextractable residue was associated more with humin and fulvic acid fractions under the aerobic condition. No significant volatile products or metabolites were detected during this study. The half-life of [(14)C]methiozolin was approximately 49 days in the soil under the aerobic condition; however, it could not be estimated in the soil under the anaerobic flooded condition because [(14)C]methiozolin degradation was limited. On the basis of these results, methiozolin is considered to undergo fast degradation by aerobic microbes, but not by anaerobic microbes in soil.

  16. Phosphorus leaching in sandy outwash soils following potato-processing wastewater application.

    PubMed

    Zvomuya, Francis; Gupta, Satish C; Rosen, Carl J

    2005-01-01

    Land application of wastewater presents potential for ground water pollution if not properly managed. In situ breakthrough tests were conducted using potato (Solanum tuberosum L.)-processing wastewater and a Br tracer to characterize P leaching in seasonally frozen sandy outwash soils. In the first test, P and Br breakthrough were measured in a 7-m deep well following wastewater [2.94 mg L(-1) total P (TP); 280 mg L(-1) Br] application at the site that had 13.1 mg water-extractable P (WEP) kg(-1)and 94.4 mg Bray-1 P kg(-1). Bromide was detected in the well after approximately 0.4 pore volumes, but there was no P break-through after 7 pore volumes. In the second breakthrough test, wastewater containing 3.6 mg L(-1) TP and 259 mg L(-1) Br was applied on 1.5-m deep lysimeters at low (0.8 mg WEP kg(-1); 12.1 mg Bray-1 P kg(-1)) and high soil test P sites (104 mg WEP kg(-1); 585 mg Bray-1 P kg(-1)). Leachate TP concentration during the test remained constant (0.04 mg L(-1)) at the low P sites but increased from approximately 3.5 to 5.6 mg L(-1) at the high P sites. These results indicate no P leaching in low P soils, but leaching in high P soils, thus suggesting that most of the P leached at the high P sites was mainly due to desorption and dissolution of weakly adsorbed P from prior P applications. This was consistent with P transport simulations using the convective-dispersive equation. We conclude that P concentration in land-applied wastewater should be regulated based on soil test-P level plus wastewater P loading.

  17. Stability Behavior and Thermodynamic States of Iron and Manganese in Sandy Soil Aquifer, Manukan Island, Malaysia

    SciTech Connect

    Lin, Chin Yik; Abdullah, Mohd. Harun; Musta, Baba; Praveena, Sarva Mangala; Aris, Ahmad Zaharin

    2011-03-15

    A total of 20 soil samples were collected from 10 boreholes constructed in the low lying area, which included ancillary samples taken from the high elevation area. Redox processes were investigated in the soil as well as groundwater in the shallow groundwater aquifer of Manukan Island, Sabah, Malaysia. Groundwater samples (n = 10) from each boreholes were also collected in the low lying area to understand the concentrations and behaviors of Fe and Mn in the dissolved state. This study strives to obtain a general understanding of the stability behaviors on Fe and Mn at the upper unsaturated and the lower-saturated soil horizons in the low lying area of Manukan Island as these elements usually play a major role in the redox chemistry of the shallow groundwater. Thermodynamic calculations using PHREEQC showed that the groundwater samples in the study area are oversaturated with respect to goethite, hematite, Fe(OH){sub 3} and undersaturated with respect to manganite and pyrochroite. Low concentrations of Fe and Mn in the groundwater might be probably due to the lack of minerals of iron and manganese oxides, which exist in the sandy aquifer. In fact, high organic matters that present in the unsaturated horizon are believed to be responsible for the high Mn content in the soil. It was observed that the soil samples collected from high elevation area (BK) comprises considerable amount of Fe in both unsaturated (6675.87 mg/kg) and saturated horizons (31440.49 mg/kg) compared to the low Fe content in the low lying area. Based on the stability diagram, the groundwater composition lies within the stability field for Mn{sup 2+} and Fe{sup 2+} under suboxic condition and very close to the FeS/Fe{sup 2+} stability boundary. This study also shows that both pH and Eh values comprise a strong negative value thus suggesting that the redox potential is inversely dependent on the changes of pH.

  18. [Effects of long-term fertilization on pH buffer system of sandy loam calcareous fluvor-aquic soil].

    PubMed

    Wang, Ji-Dong; Qi, Bing-Jie; Zhang, Yong-Chun; Zhang, Ai-Jun; Ning, Yun-Wang; Xu, Xian-Ju; Zhang, Hui; Ma, Hong-Bo

    2012-04-01

    Soil samples (0-80 cm) were collected from a 30-year fertilization experimental site in Xuzhou, Jiangsu Province of East China to study the variations of the pH, calcium carbonate and active calcium carbonate contents, and pH buffer capacity of sandy loam calcareous fluvor-aquic soil under different fertilization treatments. Thirty-year continuous application of different fertilizers accelerated the acidification of topsoil (0-20 cm), with the soil pH decreased by 0.41-0.70. Under different fertilization, the soil pH buffer capacity (pHBC) varied from 15.82 to 21.96 cmol x kg(-1). As compared with no fertilization, single N fertilization decreased the pHBC significantly, but N fertilization combined with organic fertilization could significantly increase the pHBC. The soil pHBC had significant positive correlations with soil calcium carbonate and active calcium carbonate contents, but less correlation with soil organic matter content and soil cation exchange capacity, suggesting that after a long-term fertilization, the sandy loam calcareous fluvor-aquic soil was still of an elementary calcium carbonate buffer system, and soil organic matter and cation exchange capacity contributed little to the buffer system. The soil calcium carbonate and active calcium carbonate contents were greater in 0-40 cm than in 40-80 cm soil layer. Comparing with soil calcium carbonate, soil active calcium carbonate was more sensitive to reflect the changes of soil physical and chemical properties, suggesting that the calcium carbonate buffer system could be further classified as soil active calcium carbonate buffer system.

  19. Characterization of biomass residues and their amendment effects on water sorption and nutrient leaching in sandy soil.

    PubMed

    Wang, Letian; Tong, Zhaohui; Liu, Guodong; Li, Yuncong

    2014-07-01

    In this study, we evaluated the efficiency of two types of biomass residues (fermentation residues from a bioethanol process, FB; brown mill residues from a papermaking process, BM) as amendments for a sandy soil. The characteristics of these residues including specific surface areas, morphologies and nutrient sorption capacity were measured. The effects of biorefinery residues on water and nutrient retention were investigated in terms of different particle sizes and loadings. The results indicated that bio-based wastes FB and BM were able to significantly improve water and nutrient retention of sandy soil. The residues with larger surface areas had better water and nutrient retention capability. Specifically, in the addition of 10% loading, FB and BM was able to improve water retention by approximately 150% and 300%, while reduce 99% of ammonium and phosphate concentration in the leachate compare to the soil control, respectively. PMID:24529394

  20. Characterization of biomass residues and their amendment effects on water sorption and nutrient leaching in sandy soil.

    PubMed

    Wang, Letian; Tong, Zhaohui; Liu, Guodong; Li, Yuncong

    2014-07-01

    In this study, we evaluated the efficiency of two types of biomass residues (fermentation residues from a bioethanol process, FB; brown mill residues from a papermaking process, BM) as amendments for a sandy soil. The characteristics of these residues including specific surface areas, morphologies and nutrient sorption capacity were measured. The effects of biorefinery residues on water and nutrient retention were investigated in terms of different particle sizes and loadings. The results indicated that bio-based wastes FB and BM were able to significantly improve water and nutrient retention of sandy soil. The residues with larger surface areas had better water and nutrient retention capability. Specifically, in the addition of 10% loading, FB and BM was able to improve water retention by approximately 150% and 300%, while reduce 99% of ammonium and phosphate concentration in the leachate compare to the soil control, respectively.

  1. Using a local-interaction model to determine the resistance to penetration of projectiles into sandy soil

    NASA Astrophysics Data System (ADS)

    Kotov, V. L.; Balandin, V. V.; Bragov, A. M.; Linnik, E. Yu.; Balandin, V. V.

    2013-07-01

    A local-interaction model describing the penetration of axisymmetric projectiles into sandy soil at a constant velocity is studied experimentally and theoretically. Two approaches to the determination of the parameters of the quadratic local-interaction model are considered. The first approach is based on the use of the solution of the problem of spherical-cavity expansion taking into account the dynamic compressibility and shear resistance of soil. In the second approach, model parameters are determined based on the experimental dependence of the resistance to penetration of conical projectiles into a sandy soil on the impact velocity. Good agreement was obtained between the results of experiments, two-dimensional numerical calculations, and calculations for the local interaction model based on the solution of the spherical-cavity expansion problem and used to determine the maximum resistance to penetration of conical and spherical projectiles.

  2. Impact of Natural Conditioners on Water Retention, Infiltration and Evaporation Characteristics of Sandy Soil

    NASA Astrophysics Data System (ADS)

    Abdel-Nasser, G.; Al-Omran, A. M.; Falatah, A. M.; Sheta, A. S.; Al-Harbi, A. R.

    Soil conditioners i.e., natural deposits and organic fertilizer are used for alleviate some of poor physical properties of sandy soils such as low water retention and inefficient water use, especially in arid and semi-arid regions such as in Saudi Arabia conditions. The present study aims to investigate the impact of clay deposits and organic fertilizer on water characteristics, cumulative infiltration and intermittent evaporation of loamy sand soil. Soil sample was collected from surface layer (0-30 cm depth) of the Agricultural Experiment and Research Station at Dierab, 40 km south west of Riyadh, Saudi Arabia. Two samples of clay deposits (CD#22 and CD#23) collected from Khyleis area, Jeddah-Madina road in addition of commercial Organic Fertilizer (OF) were used in the present study. The experiments were done during August to December 2005 in soil physics laboratory, the soil was mixed with clay deposits and organic fertilizer at rates of 0, 1, 2.5, 5.0 and 10.0% (w/w). The transparent PVC columns were packed with soil to depth of 30 cm every 5.0 cm intervals to insure a homogeneity of soil in columns. The clay deposits (CD#22 and CD#23) and Organic Fertilizer (OF) mixed with the soil were packed in the upper 0-5.0 cm of each soil column. The infiltration experiment was done using a flooding apparatus (Marriot device) with constant head of 3.0 cm over the soil surface. The cumulative infiltration and wetting front depth as a function of time were recorded. The evaporation experiment was conducted in 40 cm long transparent sectioned Lucite cylinders (5.0 cm ID). Fifty millimeters of tap water were applied weekly for three wetting/drying cycles. Cumulative evaporation against time was measured daily by weighing each soil column. The soil moisture distribution at the end of the experiment was determined gravimetrically for each 5.0 cm interval. The results indicated that the three conditioners significantly increased the water constants of mixed soil (i.e., SWC, FC

  3. Quasi 3D modelling of water flow in the sandy soil

    NASA Astrophysics Data System (ADS)

    Rezaei, Meisam; Seuntjens, Piet; Joris, Ingeborg; Boënne, Wesley; De Pue, Jan; Cornelis, Wim

    2016-04-01

    Monitoring and modeling tools may improve irrigation strategies in precision agriculture. Spatial interpolation is required for analyzing the effects of soil hydraulic parameters, soil layer thickness and groundwater level on irrigation management using hydrological models at field scale. We used non-invasive soil sensor, a crop growth (LINGRA-N) and a soil hydrological model (Hydrus-1D) to predict soil-water content fluctuations and crop yield in a heterogeneous sandy grassland soil under supplementary irrigation. In the first step, the sensitivity of the soil hydrological model to hydraulic parameters, water stress, crop yield and lower boundary conditions was assessed after integrating models at one soil column. Free drainage and incremental constant head conditions were implemented in a lower boundary sensitivity analysis. In the second step, to predict Ks over the whole field, the spatial distributions of Ks and its relationship between co-located soil ECa measured by a DUALEM-21S sensor were investigated. Measured groundwater levels and soil layer thickness were interpolated using ordinary point kriging (OK) to a 0.5 by 0.5 m in aim of digital elevation maps. In the third step, a quasi 3D modelling approach was conducted using interpolated data as input hydraulic parameter, geometric information and boundary conditions in the integrated model. In addition, three different irrigation scenarios namely current, no irrigation and optimized irrigations were carried out to find out the most efficient irrigation regime. In this approach, detailed field scale maps of soil water stress, water storage and crop yield were produced at each specific time interval to evaluate the best and most efficient distribution of water using standard gun sprinkler irrigation. The results show that the effect of the position of the groundwater level was dominant in soil-water content prediction and associated water stress. A time-dependent sensitivity analysis of the hydraulic

  4. Short-term biodegradation of petroleum in planted and unplanted sandy soil.

    PubMed

    Cartmill, Andrew D; Cartmill, Donita L; Alarcón, Alejandro

    2013-07-01

    A greenhouse experiment was conducted to determine the effect of microbial populations and biodegradation of petroleum hydrocarbons in Lam. 'Passerel Plus' planted and unplanted contaminated sandy soil. Plant adaptation, growth, photosynthesis, rhizosphere microbial population, and total petroleum hydrocarbon (TPH) degradation were determined. Petroleum contamination resulted in reduced plant growth, photosynthesis, and macro- and micronutrient content. Filamentous fungi populations were stimulated by the petroleum concentrations, especially when plants were exposed to intermediate to high petroleum contamination. In general, unplanted containers had lower bacterial colony forming units compared with planted containers. Thus, bacterial populations were stimulated by the rhizosphere effect of when compared with fungal populations. Degradation of TPH was greater in the lower petroleum concentration when compared with the higher petroleum concentrations in the soil and was not affected by plant presence. Nevertheless, the TPH biodegradation occurred at greater rates: 48 mg kg d for concentration of 3000 mg kg and 66 and 165 mg kg d for concentrations of 6000 and 15,000 mg kg, respectively, which concurs with the high fungal and bacterial populations with increasing petroleum concentrations regardless of plant presence.

  5. Desorption kinetics of benzene in a sandy soil in the presence of powdered activated carbon.

    PubMed

    Choi, J-W; Kim, S-B; Kim, D-J

    2007-02-01

    Desorption kinetics of benzene was investigated with a modified biphasic desorption model in a sandy soil with five different powdered activated carbon (PAC) contents (0, 1, 2, 5, 10% w/w) as sorbents. Sorption experiments followed by series dilution desorption were conducted for each sorbent. Desorption of benzene was successively performed at two stages using deionized water and hexane. Modeling was performed on both desorption isotherm and desorption rate for water-induced desorption to elucidate the presence of sorption-desorption hysteresis and biphasic desorption and if present to quantify the desorption-resistant fraction (q (irr)) and labile fraction (F) of desorption site responsible for rapid process. Desorption isotherms revealed that sorption-desorption exhibited a severe hysteresis with a significant fraction of benzene being irreversibly adsorbed onto both pure sand and PAC, and that desorption-resistant fraction (q (irr)) increased with PAC content. Desorption kinetic modeling showed that desorption of benzene was biphasic with much higher (4-40 times) rate constant for rapid process (k (1)) than that for slow process (k (2)), and that the difference in the rate constant increased with PAC content. The labile fraction (F) of desorption site showed a decreasing tendency with PAC. The experimental results would provide valuable information on remediation methods for soils and groundwater contaminated with BTEX.

  6. Hydrological components of a young loblolly pine plantation on a sandy soil with estimates of water use and loss

    NASA Astrophysics Data System (ADS)

    Abrahamson, Deborah A.; Dougherty, P. M.; Zarnoch, S. J.

    1998-12-01

    Fertilizer and irrigation treatments were applied in a 7- to 10-year-old loblolly pine (Pinus taeda L.) plantation on a sandy soil near Laurinburg, North Carolina. Rainfall, throughfall, stemflow, and soil water content were measured throughout the study period. Monthly interception losses ranged from 4 to 15% of rainfall. Stemflow ranged from 0.2 to 6.5% of rainfall. Rainfall, leaf area index (LAI), basal area (BA), and the interactions of rainfall with LAI or BA influenced prediction models of throughfall, but not stemflow, on a stand level. We found significant differences due to the effects of treatments in the soil water of the top 0.5- and 1-m soil layers by the beginning of the second growing season and throughout the remainder of the study period. Average daily water use and loss from a 1-m soil layer reflected the low water-holding capacity of the sand. Soil water in a 1-m layer was rapidly depleted to within 10% of available water during periods of little or no rainfall. Irrigation did not significantly affect productivity and created a greater potential for loss of water to drainage below 1 m. On the basis of Zahner's [1966] method of soil water depletion in a sandy soil under forest cover, total drainage to below l m was 55% of evapotranspiration in unirrigated plots and 150% of evapotranspiration in irrigated plots.

  7. Field performance of nine soil water content sensors on a sandy loam soil in new brunswick, maritime region, Canada.

    PubMed

    Chow, Lien; Xing, Zisheng; Rees, Herb W; Meng, Fanrui; Monteith, John; Stevens, Lionel

    2009-01-01

    An in situ field test on nine commonly-used soil water sensors was carried out in a sandy loam soil located in the Potato Research Center, Fredericton, NB (Canada) using the gravimetric method as a reference. The results showed that among the tested sensors, regardless of installation depths and soil water regimes, CS615, Trase, and Troxler performed the best with the factory calibrations, with a relative root mean square error (RRMSE) of 15.78, 16.93, and 17.65%, and a r(2) of 0.75, 0.77, and 0.65, respectively. TRIME, Moisture Point (MP917), and Gopher performed slightly worse with the factory calibrations, with a RRMSE of 45.76, 26.57, and 20.41%, and a r(2) of 0.65, 0.72, and 0.78, respectively, while the Gypsum, WaterMark, and Netafim showed a frequent need for calibration in the application in this region. PMID:22291570

  8. Microbial transformation of 2,4,6-trinitrotoluene in aerobic soil columns

    SciTech Connect

    Bruns-Nagel, D.; Breitung, J.; Loew, E. von

    1996-07-01

    The explosive 2,4,6-trinitrotoluene (TNT) is a common contaminant of soil and groundwater at former muntion plants and their dumping sites. TNT is toxic to numerous organisms. This paper reports on an efficient aerobic circulating percolation reactor system for the microbial detoxification of TNT-contaminated soil. 36 refs., 4 figs., 1 tab.

  9. AEROBIC SOIL MICROCOSMS FOR LONG-TERM BIODEGRADATION OF HYDROCARBON VAPORS

    EPA Science Inventory

    The aims of this research project included the development of laboratory protocols for the preparation of aerobic soil microcosms using aseptic field soil samples, and for the gas chromatographic analysis of hydrocarbon vapor biodegradation based on vapor samples obtained from th...

  10. Distribution and fractionation of cadmium, copper, lead, nickel, and zinc in a calcareous sandy soil receiving municipal solid waste.

    PubMed

    Jalali, Mohsen; Arfania, Hamed

    2011-02-01

    This study was conducted to evaluate the degree of mobility and fractionation of cadmium (Cd), copper (Cu), lead (Pb), nickel (Ni), and zinc (Zn) after the addition of municipal solid sewage sludge (MSS) in a sandy calcareous soil. Treatments were (1) soil application of MSS, (2) soil application of enriched municipal solid waste compost (EMSS), and (3) control soil. The MSS application represented a dose of 200 Mg dry weight per hectare. Soil columns were incubated at room temperature for 15 days and irrigated daily with deionized water to make a total of 505 mm. At the end of leaching experiments, soil samples from each column were divided into 14 layers, each being 1 cm down to 10 and 2.5 cm below that and analyzed for diethylenetriaminepentaacetic acid (DTPA)-extractable Cd, Cu, Pb, Ni, and Zn. The fractionation of the heavy metals in the top five layers of the surface soil samples was investigated by the sequential extraction method. All soil layers of the columns receiving MSS and EMSS had significantly higher concentrations of DTPA-extractable heavy metals than control soil. The maximum concentration of heavy metals in treated soil was in the surface layer and declined significantly with depth. Sequential extraction results showed that in the treated soil, a major proportion of Cd, Pb, and Ni was associated with organic matter (OM) and exchangeable (EXCH) fractions, and a major proportion of Cu and Zn was associated with residual (RES) and OM fractions. Based on relative percent, Pb, Cd, and Ni in the EXCH fraction was higher than Cu and Zn in soil leached with MSS and EMSS, suggesting that application of this MSS to a sandy calcareous soil, at the loading rate used here, may pose a risk in terms of groundwater contamination with Pb, Cd, and Ni.

  11. Effect of biochar and compost application on quantity, quality and stability of organic carbon in sandy soil

    NASA Astrophysics Data System (ADS)

    Holes, Annamaria; Szegi, Tamas; Fuchs, Marta; Micheli, Erika; Aleksza, Laszlo

    2014-05-01

    Nowadays the amount of waste is increasing as a consequence of civilization development. Significant proportion of municipal waste is biodegradable. For the treatment of these wastes composting and pyrolysis can be one solution. Many studies were published on the effects of composts in soils, but on combined application of biochars and composts only a limited number of articles are available. Total carbon content, water soluble organic carbon content and organic matter quality have decisive role in the utilization of soils. In our study the effects of combined application of biochars and compost on organic carbon quality, quantity and stability were measured in sandy soil. The sandy soil was mixed with different proportions (1w/w%, 2,5w/w%, 5w/w%, 10w/w%) of biochars. Two types of biochars produced by pyrolization were used: plant origin biochar (POB) and animal origin biochar (AOB). 20w/w% urban green compost was mixed into each sample in addition to biochars. After the 30 days of wet incubation soil organic carbon (SOC) content was determined by Walkley-Black method, while for the SOC quality measurements E4/E6 method was used. The dissolved organic carbon (DOC) was extracted from the soil samples by cold water, and determined by titrimetric method. The future purpose of our study is to find the optimal compost-biochar treatment in order to improve soil fertility and maximize crop yield.

  12. Virus removal by soil passage at field scale and groundwater protection of sandy aquifers.

    PubMed

    Schijven, J F; Hassanizadeh, S M

    2002-01-01

    Virus removal from groundwater by soil passage often appears to be much higher during the first few metres due to the presence of more favorable sites for attachment than thereafter. A model is presented which interprets virus removal as a function of collision efficiencies alpha(beta) and alpha(lambda), inactivation rate coefficient mu(t) and rate parameter gamma. Initial high removal is determined by ab, which decreases exponentially at a rate g to a constant base removal rate that is determined by alpha(lambda) and mu(t). A hypothetical worst case was simulated to calculate the travel distance and time required for 9 log10 protection against virus contamination of groundwater wells in anoxic sandy aquifers. Unfavorable conditions for attachment were assumed. Virus was constantly leaking from a sewage pipe lying at the groundwater table. Mixing reduced virus concentration by 3.1 to 4.0 log10. For an additional 5.0 to 5.9 l log10 protection against virus contamination by attachment and inactivation, residence times of about three to seven times longer than the current guideline of 60 days are needed, depending on abstraction rates, aquifer thickness and grain size of the sand.

  13. Soil water repellency patterns following long-term irrigation with waste water in a sandy calcareous soil, SE Spain

    NASA Astrophysics Data System (ADS)

    Mataix-Solera, J.; García-Irles, L.; Morugán, A.; Doerr, S. H.; García-Orenes, F.; Atanassova, I.; Navarro, M. A.; Ayguadé, H.

    2009-04-01

    One of the consequences of long-term irrigation with waste water can be the development of soil water repellency (WR). Its emergence can affect soil-water balance, irrigation efficiency and crop yield. Water repellency development has been suggested to be controlled by parameters such as organic matter quantity and type present in the waste water, soil properties (particularly the texture), and the overall time period of irrigation. Here we examine the effect of long-term (~20 years) irrigation with low quality waste-water on soil wettability under a Populus alba tree stand used as a "green filter". The plot exhibited considerable micro-topography (ridges and furrows) and consisted of sandy calcareous soil (Xerofluvent). Water repellency and organic carbon content (OC) were studied in 160 samples taken from the plot and from an adjacent area used as control (no irrigated). From the control area 40 samples were taken from the first 5 cm of mineral soil (C samples). From the irrigated plot a total of 120 samples were collected. To account for the micro-topography of the terrain, 40 samples each were taken from ridges (R samples; 0-5 cm depth), furrows (F samples; 0-5 cm depth), and from furrows at depth (FD samples, 5-10 cm depth). Soil WR was assessed in the laboratory for all air dry samples using the water drop penetration time test (WDPT Test). Samples with WDPT ? 5 seconds were classified as non-repellent. Organic carbon content (OC) was analyzed in all samples by potassium dichromate oxidation method. We also carried out a detailed chemical characterisation of the organic matter in two furrow samples that exhibited contrasting wettability, but no major difference in OC content (F10: WDPT 9960s, OC 6.7%; F31: WDPT 10s, OC 7.5%). Following accelerated solvent extraction with Dichloro-methane/MeOH (95:5), the extract was analysed by GC-MS. All samples from the control area (C) were wettable (mean WDPT=1s). In the irrigated plot, water repellency was present for 48

  14. [Responses of Artemisia ordosica population to soil moisture spatial heterogeneity on semi-fixed dune of Mu Us sandy land].

    PubMed

    Lu, Jianguo; Wang, Haitao; He, Xingdong; Gao, Yubao

    2006-08-01

    Spatial heterogeneity affects the functions and processes of ecosystems. By the methods of statistics and geostatistics, this paper approached the relationships between the spatial heterogeneities of Artemisia ordosica and soil moisture on the semi-fixed dune of Mu Us sandy land. The results showed that on plot-scale (80 m x 80 m), the spatial heterogeneity of A. ordosica biomass and density was dependant on that of soil moisture, and in particular, there existed a significant positive correlation between the biomass and the moisture, indicating that on semi-fixed dune, soil moisture played a decisive role in the spatial heterogeneity of plant population. Due to the redistribution of precipitation on sand dune, the outcomes of the interactions between the spatial heterogeneities of soil moisture and A. ordosica population were assumed as patchness of terrain --> patchness of soil moisture distribution --> patchness of A. ordosica population distribution --> patchness of A. ordosica biomass and density.

  15. Microbial Transformation of 2,4,6-Trinitrotoluene in Aerobic Soil Columns

    PubMed Central

    Bruns-Nagel, D.; Breitung, J.; von Low, E.; Steinbach, K.; Gorontzy, T.; Kahl, M.; Blotevogel, K.; Gemsa, D.

    1996-01-01

    2,4,6-Trinitrotoluene (TNT)-contaminated soil material of a former TNT production plant was percolated aerobically in soil columns. Nineteen days of percolation with a potassium phosphate buffer supplemented with glucose or glucose plus ammonium sulfate caused an over 90% decline in the amount of extractable nitroaromatics in soils containing 70 to 2,100 mg of TNT per kg (dry weight). In the percolation solution, a complete elimination of TNT was achieved. Mutagenicity and soil toxicity were significantly reduced by the percolation process. 4-N-Acetylamino-2-amino-6-nitrotoluene was generated in soil and percolation fluid as a labile TNT metabolite. PMID:16535369

  16. Soil development in OSL dated sandy dune substrates under Quercus robur Forest (Netherlands)

    NASA Astrophysics Data System (ADS)

    van Mourik, J. M.; Nierop, Ir. K.; Verstraten, J. M.

    2009-04-01

    Coastal dune landscapes are very dynamic. The present distribution of vegetation and soil is the result of over 2000 years of natural processes and human management. The initial soil development was controlled by an increase of the organic matter content, which consisted mainly of decomposed roots of grasses (rhizomull), and a decrease of the soil pH to 3-4 by decalcification. This stage was followed by the development of a deciduous forest, which was dominated by Quercus robur. Since 1600 AD, a large part of the deciduous forest that dominated the east side of the coastal dune landscape transferred in expensive residential areas and urbanizations. Nevertheless some parts of the oak forest belt remained. The present forest soils are acid and the controlling soil processes are leaching of sesquioxides and storage of organic matter in mormoder humus forms. The sustainability of ecosystems is closely related to the quality of the humus form, controlling nutrient cycling and water supply. Therefore, improve of knowledge of humus form development and properties is important. We applied soil micromorphology and pyrolysis-gas chromatography/mass spectrometry (GC/MS) to investigate more details of humus form development at two locations (Duivendrift and Hoek van Klaas) in the coastal dune area of the Amsterdamse Waterleidingduinen (near Haarlem, the Netherlands). However, to understand forest soil development, including the organic matter composition in the humus form, the age of the substrate and the forest is required. Therefore, we used tradition techniques as pollen analysis and radiocarbon dating but also the recently introduced optical stimulated luminescence (OSL) dating technique. OSL dating works excellent for aeolian sandy deposits with a high percentage of quartz grains. The OSL age is defined as the time after the last bleaching by solar radiation of mineral grains. Or in other words, the start of a stable period without sand drifting. In the Ah horizons we

  17. No-tillage lessens soil CO2 emissions the most under arid and sandy soil conditions: results from a meta-analysis

    NASA Astrophysics Data System (ADS)

    Abdalla, Khatab; Chivenge, Pauline; Ciais, Philippe; Chaplot, Vincent

    2016-06-01

    The management of agroecosystems plays a crucial role in the global carbon cycle with soil tillage leading to known organic carbon redistributions within soils and changes in soil CO2 emissions. Yet, discrepancies exist on the impact of tillage on soil CO2 emissions and on the main soil and environmental controls. A meta-analysis was conducted using 46 peer-reviewed publications totaling 174 paired observations comparing CO2 emissions over entire seasons or years from tilled and untilled soils across different climates, crop types and soil conditions with the objective of quantifying tillage impact on CO2 emissions and assessing the main controls. On average, tilled soils emitted 21 % more CO2 than untilled soils, which corresponded to a significant difference at P<0.05. The difference increased to 29 % in sandy soils from arid climates with low soil organic carbon content (SOCC < 1 %) and low soil moisture, but tillage had no impact on CO2 fluxes in clayey soils with high background SOCC (> 3 %). Finally, nitrogen fertilization and crop residue management had little effect on the CO2 responses of soils to no-tillage. These results suggest no-tillage is an effective mitigation measure of carbon dioxide losses from dry land soils. They emphasize the importance of including information on soil factors such as texture, aggregate stability and organic carbon content in global models of the carbon cycle.

  18. Response of N2O emissions to biochar amendment in a cultivated sandy loam soil during freeze-thaw cycles

    NASA Astrophysics Data System (ADS)

    Liu, Xiang; Wang, Quan; Qi, Zhiming; Han, Jiangang; Li, Lanhai

    2016-10-01

    In the last decade, an increasing number of studies have reported that soil nitrous oxide (N2O) emissions can be reduced by adding biochar. However, the effect of biochar amendment on soil N2O emissions during freeze-thaw cycle (FTC) is still unknown. In this laboratory study, biochar (0%, 2% and 4%, w/w) was added into a cultivated sandy loam soil and then treated with 15 times of FTC (each FTC consisted of freeze at ‑5/‑10 °C for 24 h and thaw at 5/10 °C for 24 h), to test whether biochar can mitigate soil N2O emissions during FTC, and estimate the relationships between N2O emissions and soil inorganic nitrogen contents/microbial biomass content/enzyme activities. The results showed that biochar amendment suppressed soil N2O emissions by 19.9–69.9% as compared to soils without biochar amendment during FTC. However, N2O emissions were only significantly correlated to soil nitrate nitrogen (NO3‑-N) contents, which decreased after biochar amendment, indicating that the decreased soil nitrification by adding biochar played an important role in mitigating N2O emissions during FTC. Further studies are needed to estimate the effectiveness of biochar amendment on reducing freeze-thaw induced N2O emissions from different soils under field conditions.

  19. Response of N2O emissions to biochar amendment in a cultivated sandy loam soil during freeze-thaw cycles

    PubMed Central

    Liu, Xiang; Wang, Quan; Qi, Zhiming; Han, Jiangang; Li, Lanhai

    2016-01-01

    In the last decade, an increasing number of studies have reported that soil nitrous oxide (N2O) emissions can be reduced by adding biochar. However, the effect of biochar amendment on soil N2O emissions during freeze-thaw cycle (FTC) is still unknown. In this laboratory study, biochar (0%, 2% and 4%, w/w) was added into a cultivated sandy loam soil and then treated with 15 times of FTC (each FTC consisted of freeze at −5/−10 °C for 24 h and thaw at 5/10 °C for 24 h), to test whether biochar can mitigate soil N2O emissions during FTC, and estimate the relationships between N2O emissions and soil inorganic nitrogen contents/microbial biomass content/enzyme activities. The results showed that biochar amendment suppressed soil N2O emissions by 19.9–69.9% as compared to soils without biochar amendment during FTC. However, N2O emissions were only significantly correlated to soil nitrate nitrogen (NO3−-N) contents, which decreased after biochar amendment, indicating that the decreased soil nitrification by adding biochar played an important role in mitigating N2O emissions during FTC. Further studies are needed to estimate the effectiveness of biochar amendment on reducing freeze-thaw induced N2O emissions from different soils under field conditions. PMID:27748462

  20. [Changes of species diversity and productivity in relation to soil properties in sandy grassland in Horqin Sand Land].

    PubMed

    Zuo, Xiao-an; Zhao, Xue-yong; Zhao, Ha-lin; Li, Yu-qiang; Guo, Yi-rui; Zhao, Yu-ping

    2007-05-01

    This study provided the analysis of changes of species diversity and productivity in relation to soil properties in six typical habitats (wet meadow, dry grassland, fixed dune, semi-fixed dune, semi- shifted dune, and shifted dune) in Horqin Sand Land. The changes of vegetation and soil properties, following the degraded process of sandy grassland, show the following trends: (1) productivity decreases gradually, (2) species diversity changes in a pattern of near-formal distribution, firstly increases from wet meadow, dry grassland, to fixed dune (at the peak), and then decreases from semi-fixed dune, semi-shifted dune, to shifted dune, while (3) contents of soil fine sand, silt, soil organic carbon, total nitrogen, and electrical conductivity, decrease consistently. Ordination technique of canonical correspondence analysis (CCA) was used to examine the relationship between the vegetation pattern and soil parameters. Results show that soil organic carbon, total nitrogen, available nitrogen, available potassium, soil water content, pH and electrical conductivity are main factors of vegetation pattern in this area. These factors are closely related to the first two canonical axes, accounting for 40% of the species-soil properties relationship, and soil nutrient is the key factor for determining the distributions of the major vegetation type and pattern. Furthermore, the correlation between species diversity or ecological dominance of the communities and gradient of soil factors is significant, shows that changes of species diversity and productivity are affected by soil nutrients, soil water content, pH and electrical conductivity. The regression model of productivity and soil property reveals that soil nutrient is the key factor to community productivity, accounting for 86.73% of the relationship between productivity-soil properties.

  1. Diversity of methanotrophs in Zoige wetland soils under both anaerobic and aerobic conditions.

    PubMed

    Yun, Juanli; Ma, Anzhou; Li, Yaoming; Zhuang, Guoqiang; Wang, Yanfen; Zhang, Hongxun

    2010-01-01

    Zoige wetland is one of the most important methane emission centers in China. The oxidation of methane in the wetland affects global warming, soil ecology and atmospheric chemistry. Despite their global significance, microorganisms that consume methane in Zoige wetland remain poorly characterized. In this study, we investigated methanotrophs diversity in soil samples from both anaerobic site and aerobic site in Zoige wetland using pmoA gene as a molecular marker. The cloning library was constructed according to the pmoA sequences detected. Four clusters of methanotrophs were detected. The phylogenetic tree showed that all four clusters detected were affiliated to type I methanotrophs. Two novel clusters (cluster 1, cluster 2) were found to relate to none of the recognized genera of methanotrophs. These clusters have no cultured representatives and reveal an ecological adaptation of particular uncultured methanotrophs in Zoige wetland. Two clusters were belonging to Methylobacter and Methylococcus separately. Denaturing gradient gel electrophoresis gel bands pattern retrieved from these two samples revealed that the community compositions of anaerobic soil and aerobic soil were different from each other while anaerobic soil showed a higher metanotrophs diversity. Real-time PCR assays of the two samples demonstrated that aerobic soil sample in Zoige wetland was 1.5 times as much copy numbers as anaerobic soil. These data illustrated that methanotrophs are a group of microorganisms influence the methane consumption in Zoige wetland.

  2. Using Biochar composts for improving sandy vineyard soils while reducing the risk of

    NASA Astrophysics Data System (ADS)

    Kammann, Claudia; Mengel, Jonathan; Mohr, Julia; Muskat, Stefan; Schmidt, Hans-Peter; Löhnertz, Otmar

    2016-04-01

    In recent years, biochar has increasingly been discussed as an option for sustainable environmentalmanagement, combining C sequestration with the aim of soil fertility improvement. Biochar has shownpositive effects in viticulture before (Genesio et al. 2015) which were largely attributed to improved water supply to the plants. However, in fertile temperate soils, the use of pure, untreated biochar does not guarantee economic benefits on the farm level (Ruysschaert et al., 2016). Hence, recent approaches started introducing biochar in management of nutrient-rich agricultural waste, e.g. in compost production (Kammann et al. 2015). Compost is frequently used in German vineyards for humus buildup and as a slow-release organic fertilizer. This, and increasingly mild, precipitation-rich winters, promoting mineralization, increase the risk of unwanted nitrate leaching losses into surface and ground waters during winter. To investigate if biochar pure, or biochar-compost mixtures and -products may have the potential to reduce nitrate leaching, we set up the following experiment: Either 30 or 60 t ha-1 of the following additives were mixed into the top 30 cm of sandy soil in large (120 L) containers, and planted with oneRiesling grapevine (Clone 198-30 GM) per container: Control (no addition), pure woody biochar, pure compost, biochar-compost (produced from the same organic feedstock than the compost, with 20 vol. - % of a woody biochar added), and pure compost plus pure biochar (same mixing ratio as in the former product). Once monthly, containers were exposed to simulated heavy rainfall that caused drainage. Leachates were collected from an outlet at the bottom of the containers, and analyzed for nutrients. The nutrient-rich additives containing compost all improved grape biomass and yield, most markedly pure compost and biochar-compost; same amendments were not significantly different. However,while the addition of the lower amount (30 t ha-1) of compost reduced nitrate

  3. [Soil moisture dynamics and water balance of Salix psammophila shrubs in south edge of Mu Us Sandy Land].

    PubMed

    An, Hui; An, Yu

    2011-09-01

    Taking the artificial sand-fixing Salix psammophila shrubs with different plant density (0.2, 0.6, and 0.8 plants x m(-2)) in Mu Us Sandy Land as test objects, this paper studied the soil moisture dynamics and evapotranspiration during growth season. There existed obvious differences in the soil moisture dynamics and evapotranspiration among the shrubs. The soil moisture content changed in single-hump-shape with the increase of plant density, and in "S" shape during growth season, being closely correlated with precipitation. The evapotranspiration was the highest (114.5 mm) in the shrubs with a density 0.8 plants x m(-1), accounting for 90.8% of the total precipitation during growth season, and the lowest (109.7 mm) in the shrubs with a density 0.6 plants x m(-2) Based on the soil moisture dynamics and water balance characteristics, the appropriate planting density of S. psammophila shrubs in Mu Us Sandy Land could be 0.6 plants x m(-2).

  4. Effects of fertilizer application to sweet corn (Zea mays.) grown on sandy soil.

    PubMed

    Orosz, Ferenc; Jakab, Samuel; Losak, Tomas; Slezak, Katalin

    2009-11-01

    In our experiment we tried to find out what kind of eventual changes in the environment and in plant chemical composition occurred in response to different fertilizer treatments applied to sweet corn (Zea mays convar. saccharata) grown on sandy soil with low humus content. The ploughed layer contained <1% CaCO3 and around 1% humus. The soil was very well supplied with P, well supplied with K, Mg, Mn and Cu, and weakly supplied with N and Ca. The treatments were planned in accordance with the recommendations, with a planned unhusked ear yield of 16 tons per hectare, of the new environmental friendly advisory system recently elaborated for field vegetable crops in Hungary. The treatments applied included: G1 (blank control)(N0P0K0), G2(N222.5P22.2K143), G3(N445 P22.5 K143), G4(N222.5 P22.5K143), G5(N222.5P22.5 K286), G6(N222.5 P22.5 K143) + Mg(1.52). According to our findings, of the composition parameters of the grains of the treatments with no fertilizer application, the invert and reducing sugar contents (4.42%, respectively 2.59% relative to fresh weight(-1)) in grains were the highest among the treatments. The same conclusion was drawn on the K 120.2, Mg 13.3, Fe 0.24, Cu 0.66 mg 100 g(-1) grain dry weight levels among minerals. In the case of the basic treatment (G2) recommended by the advisory system we obtained favourable results for the measured parameters, including yields. Invert and reducing sugar contents were (3.26% respectively 1.97% relative to fresh weight(-1)), and mineral contents K 101.9; Mg 11.8; Fe 0.21; Cu 0.56 mg 100 g(-1) dry weight. In the grains, no translocation of toxic elements was observed in response to the direct or indirect effect of the treatments. PMID:20329385

  5. Factors driving the carbon mineralization priming effect in a sandy loam soil amended with different types of biochar

    NASA Astrophysics Data System (ADS)

    Cely, P.; Tarquis, A. M.; Paz-Ferreiro, J.; Méndez, A.; Gascó, G.

    2014-06-01

    The effect of biochar on the soil carbon mineralization priming effect depends on the characteristics of the raw materials, production method and pyrolysis conditions. The goal of the present study is to evaluate the impact of three different types of biochar on physicochemical properties and CO2 emissions of a sandy loam soil. For this purpose, soil was amended with three different biochars (BI, BII and BIII) at a rate of 8 wt% and soil CO2 emissions were measured for 45 days. BI is produced from a mixed wood sieving from wood chip production, BII from a mixture of paper sludge and wheat husks and BIII from sewage sludge. Cumulative CO2 emissions of biochars, soil and amended soil were well fit to a simple first-order kinetic model with correlation coefficients (r2) greater than 0.97. Results show a negative priming effect in the soil after addition of BI and a positive priming effect in the case of soil amended with BII and BIII. These results can be related to different biochar properties such as carbon content, carbon aromaticity, volatile matter, fixed carbon, easily oxidized organic carbon or metal and phenolic substance content in addition to surface biochar properties. Three biochars increased the values of soil field capacity and wilting point, while effects over pH and cation exchange capacity were not observed.

  6. Genome Sequence of "Pedosphaera parvula" Ellin514, an Aerobic Verrucomicrobial Isolate from Pasture Soil

    SciTech Connect

    Kant, Ravi; Van Passel, Mark W.J.; Palva, Airi; Lucas, Susan; Copeland, A; Lapidus, Alla L.; Glavina Del Rio, Tijana; Dalin, Eileen; Tice, Hope; Bruce, David; Goodwin, Lynne A.; Pitluck, Sam; Chertkov, Olga; Larimer, Frank W; Land, Miriam L; Hauser, Loren John; Brettin, Thomas S; Detter, J. Chris; Han, Cliff; De Vos, Willem M.; Janssen, Peter H.; Smidt, Hauke

    2011-01-01

    Pedosphaera parvula Ellin514 is an aerobically grown verrucomicrobial isolate from pasture soil. In contrast to the high abundance of members of Verrucomicrobia subdivision 3 based on molecular surveys in terrestrial environments, Ellin514 is one of the few cultured representatives of this group.

  7. Spectroscopic characterization of organic matter of a soil and vinasse mixture during aerobic or anaerobic incubation

    SciTech Connect

    Doelsch, Emmanuel Masion, Armand; Cazevieille, Patrick

    2009-06-15

    Mineralization potentials are often used to classify organic wastes. These methods involve measuring CO{sub 2} production during batch experiments, so variations in chemical compounds are not addressed. Moreover, the physicochemical conditions are not monitored during the reactions. The present study was designed to address these deficiencies. Incubations of a mixture of soil and waste (vinasse at 20% dry matter from a fermentation industry) were conducted in aerobic and anaerobic conditions, and liquid samples obtained by centrifugation were collected at 2 h, 1 d and 28 d. Dissolved organic carbon (DOC) patterns highlighted that: there was a 'soil effect' which increased organic matter (OM) degradation in all conditions compared to vinasse incubated alone; and OM degradation was faster under aerobic conditions since 500 mg kg{sup -1} of C remained after aerobic incubation, as compared to 4000 mg kg{sup -1} at the end of the anaerobic incubation period. No changes were detected by Fourier transform infrared spectroscopy (FTIR) between 2 h and 1 d incubation. At 28 days incubation, the FTIR signal of the aerobic samples was deeply modified, thus confirming the high OM degradation. Under anaerobic conditions, the main polysaccharide contributions ({nu}(C-O)) disappeared at 1000 and 1200 cm{sup -1}, as also confirmed by the {sup 13}C NMR findings. Under aerobic incubation, a 50% decrease in the polysaccharide proportion was observed. Under anaerobic conditions, significant chemical modifications of the organic fraction were detected, namely formation of low molecular weight organic acids.

  8. Effects of sandy desertified land rehabilitation on soil carbon sequestration and aggregation in an arid region in China.

    PubMed

    Su, Yong Zhong; Wang, Xue Fen; Yang, Rong; Lee, Jaehoon

    2010-11-01

    The rehabilitation of sandy desertified land in semi-arid and arid regions has a great potential to increase carbon sequestration and improve soil quality. Our objective was to investigate the changes in the soil carbon pool and soil properties of surface soil (0-15 cm) under different types of rehabilitation management. Our study was done in the short-term (7 years) and long-term (32 years) desertification control sites in a marginal oasis of northwest China. The different management treatments were: (1) untreated shifting sand land as control; (2) sand-fixing shrubs with straw checkerboards; (3) poplar (Populus gansuensis) shelter forest; and (4) irrigated cropland after leveling sand dune. The results showed that the rehabilitation of severe sandy desertified land resulted in significant increases in soil organic C (SOC), inorganic C, and total N concentrations, as well as enhanced soil aggregation. Over a 7-year period of revegetation and cultivation, SOC concentration in the recovered shrub land, forest land and irrigated cropland increased by 4.1, 14.6 and 11.9 times compared to the control site (shifting sand land), and increased by 11.2, 17.0 and 23.0 times over the 32-year recovery period. Total N, labile C (KMnO(4)-oxidation C), C management index (CMI) and inorganic C (CaCO(3)-C) showed a similar increasing trend as SOC. The increased soil C and N was positively related to the accumulation of fine particle fractions. The accumulation of silt and clay, soil C and CaCO(3) enhanced the formation of aggregates, which was beneficial to mitigate wind erosion. The percentage of >0.25 mm dry aggregates increased from 18.0% in the control site to 20.0-87.2% in the recovery sites, and the mean weight diameter (MWD) of water-stable aggregates significantly increased, with a range of 0.09-0.30 mm at the recovery sites. Long-term irrigation and fertilization led to a greater soil C and N accumulation in cropland than in shrub and forest lands. The amount of soil C

  9. Effects of sandy desertified land rehabilitation on soil carbon sequestration and aggregation in an arid region in China.

    PubMed

    Su, Yong Zhong; Wang, Xue Fen; Yang, Rong; Lee, Jaehoon

    2010-11-01

    The rehabilitation of sandy desertified land in semi-arid and arid regions has a great potential to increase carbon sequestration and improve soil quality. Our objective was to investigate the changes in the soil carbon pool and soil properties of surface soil (0-15 cm) under different types of rehabilitation management. Our study was done in the short-term (7 years) and long-term (32 years) desertification control sites in a marginal oasis of northwest China. The different management treatments were: (1) untreated shifting sand land as control; (2) sand-fixing shrubs with straw checkerboards; (3) poplar (Populus gansuensis) shelter forest; and (4) irrigated cropland after leveling sand dune. The results showed that the rehabilitation of severe sandy desertified land resulted in significant increases in soil organic C (SOC), inorganic C, and total N concentrations, as well as enhanced soil aggregation. Over a 7-year period of revegetation and cultivation, SOC concentration in the recovered shrub land, forest land and irrigated cropland increased by 4.1, 14.6 and 11.9 times compared to the control site (shifting sand land), and increased by 11.2, 17.0 and 23.0 times over the 32-year recovery period. Total N, labile C (KMnO(4)-oxidation C), C management index (CMI) and inorganic C (CaCO(3)-C) showed a similar increasing trend as SOC. The increased soil C and N was positively related to the accumulation of fine particle fractions. The accumulation of silt and clay, soil C and CaCO(3) enhanced the formation of aggregates, which was beneficial to mitigate wind erosion. The percentage of >0.25 mm dry aggregates increased from 18.0% in the control site to 20.0-87.2% in the recovery sites, and the mean weight diameter (MWD) of water-stable aggregates significantly increased, with a range of 0.09-0.30 mm at the recovery sites. Long-term irrigation and fertilization led to a greater soil C and N accumulation in cropland than in shrub and forest lands. The amount of soil C

  10. Impact of Offshore Wind Energy Plants on the Soil Mechanical Behaviour of Sandy Seafloors

    NASA Astrophysics Data System (ADS)

    Stark, Nina; Lambers-Huesmann, Maria; Zeiler, Manfred; Zoellner, Christian; Kopf, Achim

    2010-05-01

    Over the last decade, wind energy has become an important renewable energy source. Especially, the installation of offshore windfarms offers additional space and higher average wind speeds than the well-established windfarms onshore. Certainly, the construction of offshore wind turbines has an impact on the environment. In the framework of the Research at Alpha VEntus (RAVE) project in the German offshore wind energy farm Alpha Ventus (north of the island Borkum in water depths of about 30 m) a research plan to investigate the environmental impact had been put into place. An ongoing study focuses on the changes in soil mechanics of the seafloor close to the foundations and the development of scour. Here, we present results of the first geotechnical investigations after construction of the plants (ca. 1 - 6 months) compared to geotechnical measurements prior to construction. To study the soil mechanical behaviour of the sand, sediment samples from about thirty different positions were measured in the laboratory to deliver, e.g., grain size (0.063 - 0.3 mm), friction angles (~ 32°), unit weight (~ 19.9 kN/m³) and void ratios (~ 0.81). For acoustic visualisation, side-scan-sonar (towed and stationary) and multibeam-echosounders (hull mounted) were used. Data show a flat, homogenous seafloor prior to windmill erection, and scouring effects at and in the vicinity of the foundations afterwards. Geotechnical in-situ measurements were carried out using a standard dynamic Cone Penetration Testing lance covering the whole windfarm area excluding areas in a radius < 50 m from the installed windmills (due the accessibility with the required research vessel). In addition, the small free-fall penetrometer Nimrod was deployed at the same spots, and furthermore, in the areas close to the tripod foundations (down to a distance of ~ 5 m from the central pile). Before construction, CPT as well as Nimrod deployments confirm a flat, homogenous sandy area with tip resistance values

  11. A New approach for evaluate a sandy soil infiltration to calculate the permeability

    NASA Astrophysics Data System (ADS)

    Mechergui, M. Mohamed; Latifa Dhaouadi, Ms

    2016-04-01

    10 sites were chosen in the four ha field of Research Regional Center of Oasis Agriculture in Deguache (Tozeur). The soil is homogeneous to the depth of 120 cm; with a sandy texture (60% big sand, 20% small sand 13% silt and 7% clay); with a mean bulk density equal to 1.43g/cm3 and with field capacity and welting point equal respectively to 11.9 and 6 %. The time duration for each infiltration essay lasted between 352 and 554 minutes. The number of observation points for each infiltration curve varies between 31 and 40. The shape of the infiltration curves observed in all sites is in part similar to what observed in literature (high increase with time of cumulative infiltration for a short time and then a linear increase of this parameter to a time varying between 122 to 197 minutes depending on the site) and then something special a slowdown in the cumulative infiltration to the end of the essay. The (F(t) / t 1/2 versus t 1/2) plotted curves showed two distinguished parts: A linear relation to the time varying between 122 and 197 minutes confirming the validity of Philips model and a second part showed a slowdown in the slope to a time varying between 231 and 347 minutes depending on the site and then drop down to the end of the essay. This is may be due to the rearrangement of particles after a long time of infiltration which led to a decrease in hydraulic conductivity. To improve the calculation of the saturated hydraulic conductivity, we choose only the part that is validated by Philips model, the linear part. The number of omitted points in the cumulative infiltration varies between 11 and 22 points. By this method, the saturated hydraulic conductivity varies between 1 and 3.72 m/day with a mean equal to 2.35. However the previous technique used gave a mean value equal to 2.07. The new method is accurate and gives better results of K and sorbtivity.

  12. Toxicities of dinitrotoluenes and trinitrobenzene freshly amended or weathered and aged in a sandy loam soil to Enchytraeus crypticus.

    PubMed

    Kuperman, Roman G; Checkai, Ronald T; Simini, Michael; Phillips, Carlton T; Kolakowski, Jan E; Kurnas, Carl W

    2006-05-01

    Scientifically based ecological soil-screening levels are needed to identify concentrations of contaminant energetic materials (EMs) in soil that present an acceptable ecological risk at a wide range of military installations. Insufficient information regarding the toxicity of 2,4-dinitrotoluene (2,4-DNT), 2,6-dinitrotoluene (2,6-DNT), and 1,3,5-trinitrobenzene (TNB) to soil invertebrates necessitated toxicity testing. We adapted the standardized Enchytraeid Reproduction Test (International Standardization Organization 16387:2003) and selected Enchytraeus crypticus for these studies. Tests were conducted in Sassafras sandy loam soil, which supports relatively high bioavailability of nitroaromatic EMs. Weathering and aging procedures for EMs amended to test soil were incorporated into the study design to produce toxicity data that better reflect the soil exposure conditions in the field compared with toxicity in freshly amended soils. This included exposing hydrated, EM-amended soils in open glass containers in the greenhouse to alternating wetting and drying cycles. Definitive tests established that the order of EM toxicity to E. crypticus based on the median effect concentration values for juvenile production in either freshly amended or weathered and aged treatments was (from the greatest to least toxicity) TNB > 2,4-DNT > 2,6-DNT. Toxicity to E. crypticus juvenile production was significantly increased in 2,6-DNT weathered and aged soil treatments compared with toxicity in freshly amended soil, based on 95% confidence intervals. This result shows that future investigations should include a weathering and aging component to generate toxicity data that provide more complete information regarding ecotoxicological effects of energetic contaminants in soil.

  13. Addition of a clay subsoil to a sandy top soil alters CO2 release and the interactions in residue mixtures.

    PubMed

    Shi, Andong; Marschner, Petra

    2013-11-01

    Addition of clay-rich subsoils to sandy top soils is an agricultural management option to increase water and nutrient retention and may also increase organic carbon sequestration by decreasing the decomposition rates. An incubation experiment was carried out in a loamy sand top soil mixed with a clay-rich subsoil (84% clay) at 0, 10 and 30% (w/w) amended with finely ground mature shoot residues of two native perennial grasses and annual barley individually or in 1:1 mixtures of two residues. Extractable C, microbial biomass C, available N and soil pH were analysed at days 0, 3, 14 and 28. Cumulative respiration after 28 days was highest with barley residue and lowest with Wallaby grass at all clay soil addition rates; 30% clay soil addition reduced cumulative respiration, especially with barley alone. In the mixture of native grasses and barley, the measured respiration was lower than expected at a clay soil addition rate of 10%. A synergistic effect (higher than expected cumulative respiration) was only found in mixture of Kangaroo grass and barley at a clay soil addition rate of 30%. Clay soil addition also decreased extractable C, available N and soil pH. The temporal change in microbial biomass C and available N in residue mixtures differed among clay addition rates. In the mixture of Wallaby grass and Kangaroo grass, microbial biomass C (MBC) decreased from day 0 to day 28 at clay soil addition rates of 0 and 10%, whereas at 30% clay MBC increased from day 0 to day 3 and then decreased. Our study shows that addition of a clay-rich subsoil to a loamy sand soil can increase C sequestration by reducing CO2 release and extractable C which are further modulated by the type of residues present individually or as mixtures.

  14. Diffusion and emissions of 1,3-dichloro propene in Florida sandy soil in microplots affected by soil moisture, organic matter, and plastic film.

    PubMed

    Thomas, John E; Allen, L Hartwell; McCormack, Leslie A; Vu, Joseph C; Dickson, Donald W; Ou, Li-Tse

    2004-04-01

    The main objective of this study was to determine the influence of soil moisture, organic matter amendment and plastic cover (a virtually impermeable film, VIF) on diffusion and emissions of (Z)- and (E)-1,3-dichloropropene (1,3-D) in microplots of Florida sandy soil (Arredondo fine sand). Upward diffusion of the two isomers in the Arredondo soil without a plastic cover was greatly influenced by soil-water content and (Z)-1,3-D diffused faster than (E)-1,3-D. In less than 5 h after 1,3-D injection to 30 cm depth, (Z)- and (E)-1,3-D in air dry soil had diffused to a 10 cm depth, whereas diffusion for the two isomers was negligible in near-water-saturated soil, even 101 h after injection. The diffusion rate of (Z)- and (E)-1,3-D in near-field-capacity soil was between the rates in the two water regimes. Yard waste compost (YWC) amendment greatly reduced diffusion of (Z)- and (E)-1,3-D, even in air-dry soil. Although upward diffusion of (Z)- and (E)-1,3-D in soil with VIF cover was slightly less than in the corresponding bare soil; the cover promoted retention of vapors of the two isomers in soil pore air in the shallow subsurface. More (Z)-1,3-D vapor was found initially in soil pore air than (E)-1,3-D although the difference declined thereafter. As a result of rapid upward movement in air-dry bare soil, (Z)- and (E)-1,3-D were rapidly volatilized into the atmosphere, but emissions from the near-water-saturated soil were minimal. Virtually impermeable film and YWC amendment retarded emissions. This study indicated that adequate soil water in this sandy soil is needed to prevent rapid emissions, but excess soil water slows diffusion of (Z)- and (E)-1,3-D. Thus, management for optimum water in soil is critical for pesticidal efficacy and the environment.

  15. Biological soil crust formation under artificial vegetation effect and its properties in the Mugetan sandy land, northeastern Qinghai-Tibet Plateau

    NASA Astrophysics Data System (ADS)

    Li, Y. F.; Li, Z. W.; Jia, Y. H.; Zhang, K.

    2016-08-01

    Mugetan sandy land is an inland desertification area of about 2,065 km2 in the northeastern Qinghai-Tibet Plateau. In the ecological restoration region of the Mugetan sandy land, different crusts have formed under the action of vegetation in three types of sandy soil (i.e. semi-fixed sand dune, fixed sand dune and ancient fixed aeolian sandy soil). The surface sand particle distribution, mineral component and vegetation composition of moving sand dunes and three types of sandy soil were studied in 2010-2014 to analyze the biological crust formation properties in the Mugetan sandy land and the effects of artificial vegetation. Results from this study revealed that artificial vegetation increases the clay content and encourages the development of biological curst. The fine particles (i.e. clay and humus) of the surface layer of the sand dunes increased more than 15% ten years after the artificial vegetation planting, and further increased up to 20% after one hundred years. The interaction of clay, humus, and other fine particles formed the soil aggregate structure. Meanwhile, under the vegetation effect from the microbes, algae, and moss, the sand particles stuck together and a biological crust formed. The interconnection of the partial crusts caused the sand dunes to gradually be fixed as a whole. Maintaining the integrity of the biological crust plays a vital role in fixing the sand under the crust. The precipitation and temperature conditions in the Mugetan sandy land could satisfy the demand of biological crust formation and development. If rational vegetation measures are adopted in the region with moving sand dunes, the lichen-moss-algae biological curst will form after ten years, but it still takes more time for the sand dunes to reach the nutrient enrichment state. If the biological curst is partly broken due to human activities, reasonable closure and restoration measures can shorten the restoration time of the biological crust.

  16. Effect of minimum tillage and mulching on maize ( Zea mays L.) yield and water content of clayey and sandy soils

    NASA Astrophysics Data System (ADS)

    Mupangwa, Walter; Twomlow, Steve; Walker, Sue; Hove, Lewis

    Rainfed smallholder agriculture in semi-arid areas of southern Africa is subject to numerous constraints. These include low rainfall with high spatial and temporal variability, and significant loss of soil water through evaporation. An experiment was established at Matopos Research Station, Zimbabwe, to determine the effect of mulching and minimum tillage on maize ( Zea mays L.) yield and soil water content. The experiment was run for two years at two sites: clay (Matopos Research Station fields) and sand (Lucydale fields) soils, in a 7 × 3 factorial combination of mulch rates (0, 0.5, 1, 2, 4, 8 and 10 t ha -1) and tillage methods (planting basins, ripper tine and conventional plough). Each treatment was replicated three times at each site in a split plot design. Maize residue was applied as mulch before tillage operations. Two maize varieties, a hybrid (SC 403) and an open pollinated variety (ZM 421), were planted. Maize yield and soil water content (0-30 and 30-60 cm depth) were measured under each treatment. On both soil types, neither mulching nor tillage method had a significant effect on maize grain yield. Tillage methods significantly influenced stover production with planting basins giving the highest stover yield (1.1 t ha -1) on sandy soil and conventional ploughing giving 3.6 t ha -1 on clay soil during the first season. The three tillage methods had no significant effect on seasonal soil water content, although planting basins collected more rainwater during the first half of the cropping period. Mulching improved soil water content in both soil types with maximum benefits observed at 4 t ha -1 of mulch. We conclude that, in the short term, minimum tillage on its own, or in combination with mulching, performs as well as the farmers’ traditional practices of overall ploughing.

  17. Vegetation pattern variation, soil degradation and their relationship along a grassland desertification gradient in Horqin Sandy Land, northern China

    NASA Astrophysics Data System (ADS)

    Zuo, Xiaoan; Zhao, Halin; Zhao, Xueyong; Guo, Yirui; Yun, Jianying; Wang, Shaokun; Miyasaka, Takafumi

    2009-09-01

    The Horqin Sandy Land is one of the most severely desertified regions in northern China. Plant communities and soil conditions at five stages of grassland desertification (potential, light, moderate, severe and very severe) were selected for the study of vegetation pattern variation relating to soil degradation. The results showed that vegetation cover, species richness and diversity, aboveground biomass (AGB), underground biomass, litter, soil organic carbon (C), total nitrogen (N), total phosphorus (P), electrical conductivity, very fine sand (0.1-0.05 mm) content and silt (0.05-0.002 mm) content decreased with the desertification development. Plant community succession presented that the palatable herbaceous plants gave place to the shrub species with asexual reproduction and sand pioneer plants. The decline of vegetation cover and AGB was positively related to the loss of soil organic C and total N with progressive desertification ( P < 0.01). The multivariate statistical analysis showed that plant community distribution, species diversity and ecological dominance had the close relationship with the gradient of soil nutrients in the processes of grassland desertification. These results suggest that grassland desertification results in the variation of vegetation pattern which presents the different composition and structure of plant community highly influenced by the soil properties.

  18. Estimating water retention curves for sandy soils at the Doñana National Park, SW Spain

    NASA Astrophysics Data System (ADS)

    Prados Garcia, M. Luisa; Vanderlinden, Karl; Guardiola-Albert, Carolina; Giraldez Cervera, Juan Vicente; Guber, Andrey K.; Pachepsky, Yakov A.

    2010-05-01

    The determination of soil water retention curves (SWRC) in the laboratory is a slow and tedious task, which is especially challenging for sandy soils due to their low water retention capacity and large water content changes for small pressure head differences. Due to spatial variability within larger areas and difficulties to obtain minimally disturbed soil samples, especially under dry conditions, laboratory measurements of the SWRCs are only suitable for guidance, as a consequence of their low representativity and accuracy. This work was developed within the framework of a research project on the ecohydrological behaviour of the soil-plant-atmosphere system within the Doñana National Park (SW Spain). In order to characterise the hydrological behaviour of the soils, a good estimation of water retention curves and hydraulic parameters is needed. Ten locations within the study area were equipped with soil moisture sensors (ECH2O-EC20, Decagon Devices Inc.) to monitor volumetric water content at different depths throughout the vadose zone. These data allow the estimation of water fluxes and recharge of the underlying aquifer, which plays a crucial role in the wetland system of the Park, declared by UNESCO as Biosphere Reserve. In this work three methods for estimating SWRCs were developed and compared. First, sand and kaolin suction tables were used to obtain SWRCs for both minimally disturbed and disturbed samples. Second, SWRC were estimated with HYDRUS-1D using the monitored volumetric soil water content data. Finally, SWRCs were estimated using the additivity hypothesis, based on the idea that SWRCs can be approximated by summing up SWRCs corresponding to different particle-size and pore-space classes of which the soil is composed. Particle-size distributions were determined in the laboratory while water retention data for the different particle-size classes were taken from literature. The comparison of these three methods allowed us to define their strengths

  19. [Characteristics of soil nematode community along an age sequence of sandy desert soil cultivation in a marginal oasis of middle reaches of Heihe River].

    PubMed

    Wang, Xue-Feng; Su, Yong-Zhong; Yang, Rong

    2010-08-01

    This paper studied the characteristics of soil nematode community following the conversion of native sandy desert soil to irrigated farmland in a marginal oasis of the middle reaches of Heihe River basin, aimed to approach the bioindicating function of soil nematodes in soil evolution process. A total of 27921 soil nematode individuals were captured, belonging to 25 families and 34 genera. The total number of nematodes increased gradually with increasing age of cultivation. At all sampling sites, bacterivores and plant parasites were the dominant trophic groups, and made up the main parts of nematode community in oasis farmland. Through the analysis of the evenness index (J) and dominance index (lambda) of nematode community, the ecosystems were found to be fragile for the farmlands having cultivated for 0, 10, and > 50 years. The maturity index MI2-5 and MMI decreased with increasing cultivation age, suggesting that the practice of agricultural use enhanced the disturbance on farmland. The soil properties changed significantly after 10 years of cultivation, which was at a significant change stage for the structure stability of soil ecosystems. The characteristics of soil nematode community could be used as the bioindicator of soil evolution following the conversion of native desert soil to irrigated farmland.

  20. [Effects of Different Residue Part Inputs of Corn Straws on CO2 Efflux and Microbial Biomass in Clay Loam and Sandy Loam Black Soils].

    PubMed

    Liu, Si-yi; Liang, Ai-zhen; Yang, Xue-ming; Zhang, Xiao-ping; Jia, Shu-xia; Chen, Xue-wen; Zhang, Shi-xiu; Sun, Bing-jie; Chen, Sheng-long

    2015-07-01

    The decomposed rate of crop residues is a major determinant for carbon balance and nutrient cycling in agroecosystem. In this study, a constant temperature incubation study was conducted to evaluate CO2 emission and microbial biomass based on four different parts of corn straw (roots, lower stem, upper stem and leaves) and two soils with different textures (sandy loam and clay loam) from the black soil region. The relationships between soil CO2 emission, microbial biomass and the ratio of carbon (C) to nitrogen (N) and lignin of corn residues were analyzed by the linear regression. Results showed that the production of CO2 was increased with the addition of different parts of corn straw to soil, with the value of priming effect (PE) ranged from 215. 53 µmol . g-1 to 335. 17 µmol . g -1. Except for corn leaves, the cumulative CO2 production and PE of clay loam soil were significantly higher than those in sandy loam soil. The correlation of PE with lignin/N was obviously more significant than that with lignin concentration, nitrogen concentration and C/N of corn residue. The addition of corn straw to soil increased the contents of MBC and MBN and decreased MBC/MBN, which suggested that more nitrogen rather than carbon was conserved in microbial community. The augmenter of microbial biomass in sandy loam soil was greater than that in clay loam soil, but the total dissolved nitrogen was lower. Our results indicated that the differences in CO2 emission with the addition of residues to soils were primarily ascribe to the different lignin/N ratio in different corn parts; and the corn residues added into the sandy loam soil could enhance carbon sequestration, microbial biomass and nitrogen holding ability relative to clay loam soil.

  1. Investigation of interactive effects on water flow and solute transport in sandy loam soil using time domain reflectometry.

    PubMed

    Merdun, Hasan

    2012-01-01

    Surface-applied chemicals move through the unsaturated zone with complex flow and transport processes due to soil heterogeneity and reach the saturated zone, resulting in groundwater contamination. Such complex processes need to be studied by advanced measurement and modeling techniques to protect soil and water resources from contamination. In this study, the interactive effects of factors like soil structure, initial soil water content (SWC), and application rate on preferential flow and transport were studied in a sandy loam field soil using measurement (by time domain reflectometry (TDR)) and modeling (by MACRO and VS2DTI) techniques. In addition, statistical analyses were performed to compare the means of the measured and modeled SWC and EC, and solute transport parameters (pore water velocity and dispersion coefficient) in 12 treatments. Research results showed that even though the effects of soil structural conditions on water and solute transport were not so clear, the applied solution moved lower depths in the profiles of wet versus dry initial SWC and high application rate versus low application rates. The effects of soil structure and initial SWC on water and solute movement could be differentiated under the interactive conditions, but the effects of the application rates were difficult to differentiate under different soil structural and initial SWC conditions. Modeling results showed that MACRO had somewhat better performance than VS2DTI in the estimation of SWC and EC with space and time, but overall both models had relatively low performances. The means of SWC, EC, and solute transport parameters of the 12 treatments were divided into some groups based on the statistical analyses, indicating different flow and transport characteristics or a certain degree nonuniform or preferential flow and transport in the soil. Conducting field experiments with more interactive factors and applying the models with different approaches may allow better understanding

  2. Investigation of Interactive Effects on Water Flow and Solute Transport in Sandy Loam Soil Using Time Domain Reflectometry

    PubMed Central

    Merdun, Hasan

    2012-01-01

    Surface-applied chemicals move through the unsaturated zone with complex flow and transport processes due to soil heterogeneity and reach the saturated zone, resulting in groundwater contamination. Such complex processes need to be studied by advanced measurement and modeling techniques to protect soil and water resources from contamination. In this study, the interactive effects of factors like soil structure, initial soil water content (SWC), and application rate on preferential flow and transport were studied in a sandy loam field soil using measurement (by time domain reflectometry (TDR)) and modeling (by MACRO and VS2DTI) techniques. In addition, statistical analyses were performed to compare the means of the measured and modeled SWC and EC, and solute transport parameters (pore water velocity and dispersion coefficient) in 12 treatments. Research results showed that even though the effects of soil structural conditions on water and solute transport were not so clear, the applied solution moved lower depths in the profiles of wet versus dry initial SWC and high application rate versus low application rates. The effects of soil structure and initial SWC on water and solute movement could be differentiated under the interactive conditions, but the effects of the application rates were difficult to differentiate under different soil structural and initial SWC conditions. Modeling results showed that MACRO had somewhat better performance than VS2DTI in the estimation of SWC and EC with space and time, but overall both models had relatively low performances. The means of SWC, EC, and solute transport parameters of the 12 treatments were divided into some groups based on the statistical analyses, indicating different flow and transport characteristics or a certain degree nonuniform or preferential flow and transport in the soil. Conducting field experiments with more interactive factors and applying the models with different approaches may allow better understanding

  3. Investigation of interactive effects on water flow and solute transport in sandy loam soil using time domain reflectometry.

    PubMed

    Merdun, Hasan

    2012-01-01

    Surface-applied chemicals move through the unsaturated zone with complex flow and transport processes due to soil heterogeneity and reach the saturated zone, resulting in groundwater contamination. Such complex processes need to be studied by advanced measurement and modeling techniques to protect soil and water resources from contamination. In this study, the interactive effects of factors like soil structure, initial soil water content (SWC), and application rate on preferential flow and transport were studied in a sandy loam field soil using measurement (by time domain reflectometry (TDR)) and modeling (by MACRO and VS2DTI) techniques. In addition, statistical analyses were performed to compare the means of the measured and modeled SWC and EC, and solute transport parameters (pore water velocity and dispersion coefficient) in 12 treatments. Research results showed that even though the effects of soil structural conditions on water and solute transport were not so clear, the applied solution moved lower depths in the profiles of wet versus dry initial SWC and high application rate versus low application rates. The effects of soil structure and initial SWC on water and solute movement could be differentiated under the interactive conditions, but the effects of the application rates were difficult to differentiate under different soil structural and initial SWC conditions. Modeling results showed that MACRO had somewhat better performance than VS2DTI in the estimation of SWC and EC with space and time, but overall both models had relatively low performances. The means of SWC, EC, and solute transport parameters of the 12 treatments were divided into some groups based on the statistical analyses, indicating different flow and transport characteristics or a certain degree nonuniform or preferential flow and transport in the soil. Conducting field experiments with more interactive factors and applying the models with different approaches may allow better understanding

  4. Heavy metal extraction from an artificially contaminated sandy soil under EDDS deficiency: significance of humic acid and chelant mixture.

    PubMed

    Yip, Theo C M; Yan, Dickson Y S; Yui, Matthew M T; Tsang, Daniel C W; Lo, Irene M C

    2010-06-01

    Biodegradable EDDS ([S,S]-ethylenediaminedisuccinic acid) has been suggested for enhancing heavy metal extraction from contaminated soils. Recent studies showed that Zn and Pb are less effectively extracted due to metal exchange and re-adsorption onto the soil surfaces, especially for EDDS-deficiency conditions. This study therefore investigated the influence of dissolved organic matter and the co-presence of EDTA (ethylene-diamine-tetraacetic acid) on metal extraction from an artificially contaminated sandy soil under deficient amount of chelants in batch kinetics experiments. The addition of 10 and 20mgL(-1) of humic acid as dissolved organic matter (DOC) suppressed metal extraction by EDDS, probably resulting from the competition of adsorbed humic acid for heavy metals and adsorption of metal-humate complexes onto the soil surfaces. The effects were most significant for Pb because of greater extent of metal exchange of PbEDDS and high affinity towards organic matter. Thus, one should be cautious when there is a high content of organic matter in soils or groundwater. On the other hand, compared to individual additions of EDDS or EDTA, the equimolar EDDS and EDTA mixture exhibited significantly higher Pb extraction without notable Pb re-adsorption. The synergistic performance of the EDDS and EDTA mixture probably resulted from the change of chemical speciation and thus less competition among Cu, Zn and Pb for each chelant. These findings suggest further investigation into an optimum chemistry of the chelant mixture taking into account the effectiveness and associated environmental impact.

  5. Community-specific impacts of exotic earthworm invasions on soil carbon dynamics in a sandy temperate forest.

    PubMed

    Crumsey, Jasmine M; Le Moine, James M; Capowiez, Yvan; Goodsitt, Mitchell M; Larson, Sandra C; Kling, George W; Nadelhoffer, Knute J

    2013-12-01

    Exotic earthworm introductions can alter above- and belowground properties of temperate forests, but the net impacts on forest soil carbon (C) dynamics are poorly understood. We used a mesocosm experiment to examine the impacts of earthworm species belonging to three different ecological groups (Lumbricus terrestris [anecic], Aporrectodea trapezoides [endogeic], and Eisenia fetida [epigeic]) on C distributions and storage in reconstructed soil profiles from a sandy temperate forest soil by measuring CO2 and dissolved organic carbon (DOC) losses, litter C incorporation into soil, and soil C storage with monospecific and species combinations as treatments. Soil CO2 loss was 30% greater from the Endogeic x Epigeic treatment than from controls (no earthworms) over the first 45 days; CO2 losses from monospecific treatments did not differ from controls. DOC losses were three orders of magnitude lower than CO2 losses, and were similar across earthworm community treatments. Communities with the anecic species accelerated litter C mass loss by 31-39% with differential mass loss of litter types (Acer rubrum > Populus grandidentata > Fagus grandifolia > Quercus rubra > or = Pinus strobus) indicative of leaf litter preference. Burrow system volume, continuity, and size distribution differed across earthworm treatments but did not affect cumulative CO2 or DOC losses. However, burrow system structure controlled vertical C redistribution by mediating the contributions of leaf litter to A-horizon C and N pools, as indicated by strong correlations between (1) subsurface vertical burrows made by anecic species, and accelerated leaf litter mass losses (with the exception of P. strobus); and (2) dense burrow networks in the A-horizon and the C and N properties of these pools. Final soil C storage was slightly lower in earthworm treatments, indicating that increased leaf litter C inputs into soil were more than offset by losses as CO2 and DOC across earthworm community treatments. PMID

  6. Community-specific impacts of exotic earthworm invasions on soil carbon dynamics in a sandy temperate forest.

    PubMed

    Crumsey, Jasmine M; Le Moine, James M; Capowiez, Yvan; Goodsitt, Mitchell M; Larson, Sandra C; Kling, George W; Nadelhoffer, Knute J

    2013-12-01

    Exotic earthworm introductions can alter above- and belowground properties of temperate forests, but the net impacts on forest soil carbon (C) dynamics are poorly understood. We used a mesocosm experiment to examine the impacts of earthworm species belonging to three different ecological groups (Lumbricus terrestris [anecic], Aporrectodea trapezoides [endogeic], and Eisenia fetida [epigeic]) on C distributions and storage in reconstructed soil profiles from a sandy temperate forest soil by measuring CO2 and dissolved organic carbon (DOC) losses, litter C incorporation into soil, and soil C storage with monospecific and species combinations as treatments. Soil CO2 loss was 30% greater from the Endogeic x Epigeic treatment than from controls (no earthworms) over the first 45 days; CO2 losses from monospecific treatments did not differ from controls. DOC losses were three orders of magnitude lower than CO2 losses, and were similar across earthworm community treatments. Communities with the anecic species accelerated litter C mass loss by 31-39% with differential mass loss of litter types (Acer rubrum > Populus grandidentata > Fagus grandifolia > Quercus rubra > or = Pinus strobus) indicative of leaf litter preference. Burrow system volume, continuity, and size distribution differed across earthworm treatments but did not affect cumulative CO2 or DOC losses. However, burrow system structure controlled vertical C redistribution by mediating the contributions of leaf litter to A-horizon C and N pools, as indicated by strong correlations between (1) subsurface vertical burrows made by anecic species, and accelerated leaf litter mass losses (with the exception of P. strobus); and (2) dense burrow networks in the A-horizon and the C and N properties of these pools. Final soil C storage was slightly lower in earthworm treatments, indicating that increased leaf litter C inputs into soil were more than offset by losses as CO2 and DOC across earthworm community treatments.

  7. Kinetics of aerobic and anaerobic biomineralization of atrazine in surface and subsurface agricultural soils in Ohio.

    PubMed

    Tuovinen, Olli H; Deshmukh, Vaidehi; Özkaya, Bestamin; Radosevich, Mark

    2015-01-01

    The purpose of this study was to assess atrazine mineralization in surface and subsurface samples retrieved from vertical cores of agricultural soils from two farm sites in Ohio. The Defiance site (NW-Ohio) was on soybean-corn rotation and Piketon (S-Ohio) was on continuous corn cultivation. Both sites had a history of atrazine application for at least a couple of decades. The clay fraction increased at the Defiance site and the organic matter and total N content decreased with depth at both sites. Mineralization of atrazine was assessed by measurement of (14)CO2 during incubation of soil samples with [U-ring-(14)C]-atrazine. Abiotic mineralization was negligible in all soil samples. Aerobic mineralization rate constants declined and the corresponding half-lives increased with depth at the Defiance site. Anaerobic mineralization (supplemented with nitrate) was mostly below the detection at the Defiance site. In Piketon samples, the kinetic parameters of aerobic and anaerobic biomineralization of atrazine displayed considerable scatter among replicate cores and duplicate biometers. In general, this study concludes that data especially for anaerobic biomineralization of atrazine can be more variable as compared to aerobic conditions and cannot be extrapolated from one agricultural site to another. PMID:26273756

  8. Kinetics of aerobic and anaerobic biomineralization of atrazine in surface and subsurface agricultural soils in Ohio.

    PubMed

    Tuovinen, Olli H; Deshmukh, Vaidehi; Özkaya, Bestamin; Radosevich, Mark

    2015-01-01

    The purpose of this study was to assess atrazine mineralization in surface and subsurface samples retrieved from vertical cores of agricultural soils from two farm sites in Ohio. The Defiance site (NW-Ohio) was on soybean-corn rotation and Piketon (S-Ohio) was on continuous corn cultivation. Both sites had a history of atrazine application for at least a couple of decades. The clay fraction increased at the Defiance site and the organic matter and total N content decreased with depth at both sites. Mineralization of atrazine was assessed by measurement of (14)CO2 during incubation of soil samples with [U-ring-(14)C]-atrazine. Abiotic mineralization was negligible in all soil samples. Aerobic mineralization rate constants declined and the corresponding half-lives increased with depth at the Defiance site. Anaerobic mineralization (supplemented with nitrate) was mostly below the detection at the Defiance site. In Piketon samples, the kinetic parameters of aerobic and anaerobic biomineralization of atrazine displayed considerable scatter among replicate cores and duplicate biometers. In general, this study concludes that data especially for anaerobic biomineralization of atrazine can be more variable as compared to aerobic conditions and cannot be extrapolated from one agricultural site to another.

  9. Experimental studies on the physico-mechanical properties of jet-grout columns in sandy and silty soils

    NASA Astrophysics Data System (ADS)

    Akin, Muge K.

    2016-04-01

    The term of ground improvement states to the modification of the engineering properties of soils. Jet-grouting is one of the grouting methods among various ground improvement techniques. During jet-grouting, different textures of columns can be obtained depending on the characteristics of surrounding subsoil as well as the adopted jet-grouting system for each site is variable. In addition to textural properties, strength and index parameters of jet-grout columns are highly affected by the adjacent soil. In this study, the physical and mechanical properties of jet-grout columns constructed at two different sites in silty and sandy soil conditions were determined by laboratory tests. A number of statistical relationships between physical and mechanical properties of soilcrete were established in this study in order to investigate the dependency of numerous variables. The relationship between qu and γd is more reliable for sandy soilcrete than that of silty columns considering the determination coefficients. Positive linear relationships between Vp and γd with significantly high determination coefficients were obtained for the jet-grout columns in silt and sand. The regression analyses indicate that the P-wave velocity is a very dominant parameter for the estimation of physical and mechanical properties of jet-grout columns and should be involved during the quality control of soilcrete material despite the intensive use of uniaxial compressive strength test. Besides, it is concluded that the dry unit weight of jet-grout column is a good indicator of the efficiency of employed operational parameters during jet-grouting.

  10. Characterization of methanotrophic bacterial populations in natural and agricultural aerobic soils of the European Russia

    NASA Astrophysics Data System (ADS)

    Kravchenko, Irina; Sukhacheva, Marina; Kizilova, Anna

    2014-05-01

    Atmospheric methane contributes to about 20% of the total radiative forcing by long-lived greenhouse gases, and microbial methane oxidation in upland soils is the only biological sink of methane. Microbial methane oxidation in aerated upland soils is estimated as 15 - 45 Tg yr-1 or 3-9% of the annual sink. Therefore there is need of extensive research to characterize methanotrophic activity in various ecosystems for possible application to reduce atmospheric methane fluxes and to minimize global climate change. The vast majority of known aerobic methanotrophs belongs to the Proteobacteria and placed in the families Methylococcaceae in the Gammaproteobacteria, and Methylocystaceae and Beijerinckiaceae in the Alphaproteobacteria. Known exceptions include the phylum Verrucomicrobia and uncultured methanotrophs such as Candidatus 'Methylomirabilis oxyfera' affiliated with the 'NC10' phylum. Plenty of studies of aerobic methane oxidation and key players of the process have been performed on various types of soils, and it was found that Methylocystis spp and uncultivated methanotrophs are abundant in upland soils. Two of the uncultured groups are upland soil cluster alphaproteobacteria (USCa) and gammaproteobacteria (USCg), as revealed by cultivation-independent surveys of pmoA diversity. Russia is extremely rich in soil types due to its vast territories, and most of these soils have never been investigated from the aspect of methanotrophy. This study addresses methane oxidation activity and diversity of aerobic methanotrophic bacteria in eight types of natural aerobic soils, four of which also had been under agricultural use. Methane fluxes have been measured by in situ static chamber method and methane oxidation rates in soil samples - by radioisotope tracer (14CH4) technique. Changes in methanotroph diversity and abundance were assessed by cloning and Sanger sequencing, and quantitative real-time PCR of pmoA genes. Methanotrophic population of unmanaged soils turned

  11. The origin and early genesis of clay bands in youthful sandy soils along lake Michigan, U.S.A.

    USGS Publications Warehouse

    Berg, R.C.

    1984-01-01

    A beach ridge and dune complex with good radiocarbon control sampling the last 3500 radiocarbon years B.P. provides new insights on the early genesis of clay bands in sandy soils. Soil profiles were sampled by age groups, described in the field, and then subjected to laboratory analyses for particle-size distribution, pH, organic carbon, carbonate minerals, and extractable iron and manganese. This study suggests that small increases in pH, brought about by small increases in carbonate content within the soil profile, are responsible for flocculating small amounts of illuviated clay. This process, along with a transition to a greater hydraulic conductivity with soil depth due to coarser textures in any given profile, partly explains the existence and possible reason for the initiation of illuvial zones and eventually for clay-band horizons. A pronounced increase in the thickness of incipient clay-band horizons in soils older than 2300 years appears due to finer textures in the parent materials than are present in younger soils. Because of slightly reduced porosity and lower permeability, carbonates and a high pH are retained in both illuvial and eluvial horizons of some of these older soils. In addition, only in those profiles older than 2300 years do clay and iron oxide concentrations coincide and is there some suggestion of greater amounts of extractable manganese in horizons of minimum iron and clay. A pronounced segregation of clay-iron bands is not apparent at the study area but should occur in future years as additional amounts of iron and clay are deposited. ?? 1984.

  12. Transport and distribution of Salmonella enterica serovar Typhimurium in loamy and sandy soil monoliths with applied liquid manure.

    PubMed

    Bech, Tina B; Johnsen, Kaare; Dalsgaard, Anders; Laegdsmand, Mette; Jacobsen, Ole Hørbye; Jacobsen, Carsten S

    2010-02-01

    A leaching experiment, where liquid manure spiked with Salmonella enterica serovar Typhimurium (Tet(+)) DSM554 was applied to soil surfaces, was conducted on intact soil monoliths (60 cm in diameter and 100 cm long). A total of 6.5 x 10(10) CFU was applied to each column. We found that Salmonella serovar Typhimurium could be transported to a 1-m depth in loamy soil at concentrations reaching 1.3 x 10(5) CFU/ml of leachate. The test strain was found in concentrations ranging from 300 to 1.3(5) cells/ml in loamy soil throughout the 27 days of the experiment, while concentrations below 20 cells/ml were sporadically detected in the leachates from sandy monoliths. Real-time PCR targeting invA DNA showed a clear correspondence between the total and culturable numbers of cells in the leachate, indicating that most cells leached were viable. On day 28, distribution of Salmonella serovar Typhimurium at five depths in the four monoliths was determined. The highest recovery rate, ranging from 1.5% to 3.8% of the total applied inoculum, was found in the top 0.2 m.

  13. Removal of Fast Flowing Nitrogen from Marshes Restored in Sandy Soils

    PubMed Central

    Sparks, Eric L.; Cebrian, Just; Smith, Sara M.

    2014-01-01

    Groundwater flow rates and nitrate removal capacity from an introduced solution were examined for five marsh restoration designs and unvegetated plots shortly after planting and 1 year post-planting. The restoration site was a sandy beach with a wave-dampening fence 10 m offshore. Simulated groundwater flow into the marsh was introduced at a rate to mimic intense rainfall events. Restoration designs varied in initial planting density and corresponded to 25%, 50%, 75% and 100% of the plot area planted. In general, groundwater flow was slower with increasing planting density and decreased from year 0 to year 1 across all treatments. Nevertheless, removal of nitrate from the introduced solution was similar and low for all restoration designs (3–7%) and similar to the unvegetated plots. We suggest that the low NO3− removal was due to sandy sediments allowing rapid flow of groundwater through the marsh rhizosphere, thereby decreasing the contact time of the NO3− with the marsh biota. Our findings demonstrate that knowledge of the groundwater flow regime for restoration projects is essential when nutrient filtration is a target goal of the project. PMID:25353607

  14. Removal of fast flowing nitrogen from marshes restored in sandy soils.

    PubMed

    Sparks, Eric L; Cebrian, Just; Smith, Sara M

    2014-01-01

    Groundwater flow rates and nitrate removal capacity from an introduced solution were examined for five marsh restoration designs and unvegetated plots shortly after planting and 1 year post-planting. The restoration site was a sandy beach with a wave-dampening fence 10 m offshore. Simulated groundwater flow into the marsh was introduced at a rate to mimic intense rainfall events. Restoration designs varied in initial planting density and corresponded to 25%, 50%, 75% and 100% of the plot area planted. In general, groundwater flow was slower with increasing planting density and decreased from year 0 to year 1 across all treatments. Nevertheless, removal of nitrate from the introduced solution was similar and low for all restoration designs (3-7%) and similar to the unvegetated plots. We suggest that the low NO3(-) removal was due to sandy sediments allowing rapid flow of groundwater through the marsh rhizosphere, thereby decreasing the contact time of the NO3(-) with the marsh biota. Our findings demonstrate that knowledge of the groundwater flow regime for restoration projects is essential when nutrient filtration is a target goal of the project.

  15. Accelerated simulation of the migration of solutes in sandy soils amended by sewage sludge: Transport and retardation

    NASA Astrophysics Data System (ADS)

    Etchebers, O.; Kedziorek, M. A.; Chossat, J.; Riou, C.; Bourg, A. C.

    2003-12-01

    A common way to dispose of sewage sludge is to spead it on agricultural land because of its high nutrient (P, N) and org C contents. However, in addition to these beneficial components, sewage sludge can contain toxic chemicals such as heavy metals. This farming technique is relatively recent (several decades, at most) and there is still a need for information concerning the processes controlling the fate of the heavy metals in the sludge. To study how fast they migrate in the soil profile, the transfer of water and associated solutes in both unsaturated and unsaturated conditions can be accelerated by centrifugation according to the equation: tsimulated = treal * g2. (t: time). In a lysimeter study (diameter 30 cm, depth 60 cm) carried out using the CEA-CESTA Silat 265 centrifuge, we simulated, at 20 g, several months of percolation in one day. Experiments were done on cores of sandy forest soil (podzol) to which various sewage sludges (containing 2 to 12 mg/kg Cd, 20 to 120 mg/kg Ni, 50 to 465 mg/kg Pb) and simulated rain were applied. Major ions migrated at an estimated rate of 6-8.5 mm/simulated day (2-3 m/simulated year), while heavy metals (Cd, Ni, Pb) were retarded by a factor of 1.5 to 2. The retention of these heavy metals is associated with the organic C content of the soil profile (rich in the upper horizon).

  16. Distributions of labeled nitrogen in the profile of a fertilized sandy soil

    SciTech Connect

    Mansell, R.S.; Fiskell, J.G.A.; Calvert, D.V.; Rogers, J.S.

    1986-02-01

    Isotopically labeled (/sup 15/N-depleted) ammonium sulfate (115 kg N ha/sup -1/) was applied to a Spodosol in a citrus grove, to determine the fate and subsequent distributions of NO/sub 3/-N and NH/sub 4/-N in the soil profile. The soil was tile-drained, and citrus trees were located on soil beds. The authors examined three soil management treatments: the original A1 horizon (ST): deep mixing of A1 and A2 horizons with the underlying Spodic horizon (DT); and incorporation of 56 Mg ha/sup -1/ of dolomitic limestone, along with deep mixing (DTL) of the profile. Soil samples were taken to the 70-cm depth in ST and to the 95-cm depth in DT and DTL soils and were extracted with 1 M KCl. Extracts were chemically analyzed for NH/sub 4/-N and NO/sub 3/-N concentrations and isotopic analysis was performed by mass spectroscopy. At 12 d after fertilization, both NH/sub 4/-N and NO/sub 3/-N values in the ST soil profile exceeded corresponding values for DT and DTL soils. This N was derived primarily from the fertilizer. With time, concentrations of both NH/sub 4/-N and NO/sub 3/-N decreased in profiles for all three soils; however, N concentrations in the ST soil consistently exceeded corresponding values for DT and DTL profiles.

  17. Sensitivity of water stress in a two-layered sandy grassland soil to variations in groundwater depth and soil hydraulic parameters

    NASA Astrophysics Data System (ADS)

    Rezaei, M.; Seuntjens, P.; Joris, I.; Boënne, W.; Van Hoey, S.; Campling, P.; Cornelis, W. M.

    2015-07-01

    Monitoring and modeling tools may improve irrigation strategies in precision agriculture. We used non-invasive soil moisture monitoring, a crop growth and a soil hydrological model to predict soil-water content fluctuations and crop yield in a heterogeneous sandy grassland soil under supplementary irrigation. The sensitivity of the model to hydraulic parameters, water stress, crop yield and lower boundary conditions was assessed. Free drainage and incremental constant head conditions was implemented in a lower boundary sensitivity analysis. A time-dependent sensitivity analysis showed that changes in soil water content are mainly affected by the soil saturated hydraulic conductivity Ks and the Mualem-van Genuchten retention curve shape parameters n and α. Results further showed that different parameter optimization strategies (two-, three-, four- or six-parameter optimizations) did not affect the calculated water stress and water content as significantly as does the bottom boundary. For this case, a two-parameter scenario, where Ks was optimized for each layer under the condition of a constant groundwater depth at 135-140 cm, performed best. A larger yield reduction, and a larger number and longer duration of stress conditions occurred in the free drainage condition as compared to constant boundary conditions. Numerical results showed that optimal irrigation scheduling using the aforementioned water stress calculations can save up to 12-22 % irrigation water as compared to the current irrigation regime. This resulted in a yield increase of 4.5-6.5 %, simulated by crop growth model.

  18. Nitrogen Amendment Stimulated Decomposition of Maize Straw-Derived Biochar in a Sandy Loam Soil: A Short-Term Study

    PubMed Central

    Lu, Weiwei; Ding, Weixin; Zhang, Junhua; Zhang, Huanjun; Luo, Jiafa; Bolan, Nanthi

    2015-01-01

    This study examined the effect of nitrogen (N) on biochar stability in relation to soil microbial community as well as biochar labile components using δ13C stable isotope technology. A sandy loam soil under a long-term rotation of C3 crops was amended with biochar produced from maize (a C4 plant) straw in absence (BC0) and presence (BCN) of N and monitored for dynamics of carbon dioxide (CO2) flux, phospholipid fatty acids (PLFAs) profile and dissolved organic carbon (DOC) content. N amendment significantly increased the decomposition of biochar during the first 5 days of incubation (P < 0.05), and the proportions of decomposed biochar carbon (C) were 2.30% and 3.28% in BC0 and BCN treatments, respectively, during 30 days of incubation. The magnitude of decomposed biochar C was significantly (P < 0.05) higher than DOC in biochar (1.75%) and part of relatively recalcitrant biochar C was mineralized in both treatments. N amendment increased soil PLFAs concentration at the beginning of incubation, indicating that microorganisms were N-limited in test soil. Furthermore, N amendment significantly (P < 0.05) increased the proportion of gram-positive (G+) bacteria and decreased that of fungi, while no noticeable changes were observed for gram-negative (G−) bacteria and actinobacteria at the early stage of incubation. Our results indicated that N amendment promoted more efficiently the proliferation of G+ bacteria and accelerated the decomposition of relatively recalcitrant biochar C, which in turn reduced the stability of maize straw-derived biochar in test soil. PMID:26192282

  19. Nitrogen Amendment Stimulated Decomposition of Maize Straw-Derived Biochar in a Sandy Loam Soil: A Short-Term Study.

    PubMed

    Lu, Weiwei; Ding, Weixin; Zhang, Junhua; Zhang, Huanjun; Luo, Jiafa; Bolan, Nanthi

    2015-01-01

    This study examined the effect of nitrogen (N) on biochar stability in relation to soil microbial community as well as biochar labile components using δ13C stable isotope technology. A sandy loam soil under a long-term rotation of C3 crops was amended with biochar produced from maize (a C4 plant) straw in absence (BC0) and presence (BCN) of N and monitored for dynamics of carbon dioxide (CO2) flux, phospholipid fatty acids (PLFAs) profile and dissolved organic carbon (DOC) content. N amendment significantly increased the decomposition of biochar during the first 5 days of incubation (P < 0.05), and the proportions of decomposed biochar carbon (C) were 2.30% and 3.28% in BC0 and BCN treatments, respectively, during 30 days of incubation. The magnitude of decomposed biochar C was significantly (P < 0.05) higher than DOC in biochar (1.75%) and part of relatively recalcitrant biochar C was mineralized in both treatments. N amendment increased soil PLFAs concentration at the beginning of incubation, indicating that microorganisms were N-limited in test soil. Furthermore, N amendment significantly (P < 0.05) increased the proportion of gram-positive (G+) bacteria and decreased that of fungi, while no noticeable changes were observed for gram-negative (G-) bacteria and actinobacteria at the early stage of incubation. Our results indicated that N amendment promoted more efficiently the proliferation of G+ bacteria and accelerated the decomposition of relatively recalcitrant biochar C, which in turn reduced the stability of maize straw-derived biochar in test soil.

  20. Olive mill wastewater stabilization in open-air ponds: impact on clay-sandy soil.

    PubMed

    Jarboui, Raja; Sellami, Fatma; Kharroubi, Adel; Gharsallah, Néji; Ammar, Emna

    2008-11-01

    The aim of this work was to study the natural biodegradation of the stored olive mill wastewater (OMW) in ponds and the infiltration as well as the impact on soil of the effluent in the evaporation pond used for the storage over the past eight years. For this, two approaches were considered. First, a laboratory-scale column was used for the infiltration of OMW through soil (clay and sand) to predict the effect of the clayey soil in reducing OMW pollution. Second, the ponds including the effluent annually stored and having this clayey structure were investigated. At the laboratory-scale, a modification of OMW contents was noticed, with the elimination of 95% of total suspended solids (TSS), 60% of chemical oxygen demand (COD), 40% of total organic carbon (TOC), 50% of total P, 50% of phenols and 40% of minerals (K+, Mg++ and Na+). The experimented soil was able to restrain the considerable effects of OMW pollution. In the ponds, the granulometric characteristics, the physico-chemical and the biological parameters of the soil profile from the contaminated pond were compared to those of a control soil, located near the contaminated pond. Property modifications of the contaminated soil were noted, especially pH, electrical conductivity, COD and microflora. These changes can be explained by the infiltration of OMW constituents, which were noticed in the soil layers, especially phenolic compounds that have a negative effect on the ground water. PMID:18337092

  1. Physical and hydraulic properties of a sandy loam soil under zero, shallow and deep tillage practices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over the centuries, tillage has been an important agronomic practice that has been used to mechanically alter soil properties and enhance the soil ecosystem for growth of crops. A 4-yr study investigated the impact of no-tillage (NT), shallow tillage at a 10-cm depth (ST), and deep tillage at a 30-c...

  2. The evolution of sandy soils under the influence of vegetation succession and anthropogenic activities - case study from Błędów Desert

    NASA Astrophysics Data System (ADS)

    Gus, Magdalena; Drewnik, Marek

    2016-04-01

    Sandy areas are an important source of research about early stages of the soils formation process and their further development. The rate of succession is reflecting the influence of vegetation on chemical and physical properties of soils which as the time goes undergo the evolution process caused by other environmental factors. The Błędów Desert (Poland, Central Europe) is an example of this kind of area, where sandy soils evolved into Podzols, but as a result of human activities conducted since Middle Ages soil cover has been destroyed to bedrock. Currently progressing vegetation succession occurred in two ways: primary, which took place in areas covered by loose sand and secondary, in the areas with fossil soils. Presently the Błędów Desert is a suitable example to study soil changes in both cases mentioned above. The main aim of the study was to present diversity and characteristics of soils in The Błędów Desert in relation to their development stages and vegetation succession. During field studies soil profiles were described and selected for the detailed studies and soils samples were taken for laboratory analysis, including a determination of basic physical and chemical analysis as well as for micromorphological analysis (selected profiles). Podzols located near the boundary of the study area was selected as a reference soils. The results proved the complexity of the soil process formation, which strongly depends on the vegetation succession and human activities including human-induced aeolian processes. Results confirmed the presence of buried soils, which together with the contemporary soils formed a soil sequence. Moreover, research shows that the dominant soil-forming processes at the Błędów Desert are humus accumulation and podzolization. To summarize, The Błędów Desert is a dynamic environment undergoing rapid changes of soil cover under the influence of the interaction of vegetation, anthropopression and aeolian processes.

  3. Root growth of Lotus corniculatus interacts with P distribution in young sandy soil

    NASA Astrophysics Data System (ADS)

    Felderer, B.; Boldt-Burisch, K. M.; Schneider, B. U.; Hüttl, R. F. J.; Schulin, R.

    2013-03-01

    Large areas of land are restored with unweathered soil substrates following mining activities in eastern Germany and elsewhere. In the initial stages of colonization of such land by vegetation, plant roots may become key agents in generating soil formation patterns by introducing gradients in chemical and physical soil properties. On the other hand, such patterns may be influenced by root growth responses to pre-existing substrate heterogeneities. In particular, the roots of many plants were found to preferentially proliferate into nutrient-rich patches. Phosphorus (P) is of primary interest in this respect because its availability is often low in unweathered soils, limiting especially the growth of leguminous plants. However, leguminous plants occur frequently among the pioneer plant species on such soils, as they only depend on atmospheric nitrogen (N) fixation as N source. In this study we investigated the relationship between root growth allocation of the legume Lotus corniculatus and soil P distribution on recently restored land. As test sites, the experimental Chicken Creek Catchment (CCC) in eastern Germany and a nearby experimental site (ES) with the same soil substrate were used. We established two experiments with constructed heterogeneity, one in the field on the experimental site and the other in a climate chamber. In addition, we conducted high-density samplings on undisturbed soil plots colonized by L. corniculatus on the ES and on the CCC. In the field experiment, we installed cylindrical ingrowth soil cores (4.5 × 10 cm) with and without P fertilization around single two-month-old L. corniculatus plants. Roots showed preferential growth into the P-fertilized ingrowth-cores. Preferential root allocation was also found in the climate chamber experiment, where single L. corniculatus plants were grown in containers filled with ES soil and where a lateral portion of the containers was additionally supplied with a range of different P concentrations. In

  4. Root growth of Lotus corniculatus interacts with P distribution in young sandy soil

    NASA Astrophysics Data System (ADS)

    Felderer, B.; Boldt-Burisch, K. M.; Schneider, B. U.; Hüttl, R. F. J.; Schulin, R.

    2012-07-01

    Large areas of land are restored with un-weathered soil substrates following mining activities in eastern Germany and elsewhere. In the initial stages of colonization of such land by vegetation, plant roots may become key agents in generating soil formation patterns by introducing gradients in chemical and physical soil properties. On the other hand, such patterns may be influenced by root growth responses to pre-existing substrate heterogeneities. In particular, the roots of many plants were found to preferentially proliferate into nutrient-rich patches. Phosphorus (P) is of primary interest in this respect because its availability is often low in unweathered soils, limiting especially the growth of leguminous plants. However, leguminous plants occur frequently among the pioneer plant species on such soils as they only depend on atmospheric nitrogen (N) fixation as N source. In this study we investigated the relationship between root growth allocation of the legume Lotus corniculatus and soil P distribution on recently restored land. As test sites the experimental Chicken Creek Catchment (CCC) in eastern Germany and a nearby experimental site (ES) with the same soil substrate were used. We established two experiments with constructed heterogeneity, one in the field on the experimental site and the other in a climate chamber. In addition we conducted high-density samplings on undisturbed soil plots colonized by L. corniculatus on the ES and on the CCC. In the field experiment, we installed cylindrical ingrowth soil cores (4.5×10 cm) with and without P fertilization around single two-month-old L. corniculatus plants. Roots showed preferential growth into the P-fertilized ingrowth-cores. Preferential root allocation was also found in the climate chamber experiment, where single L. corniculatus plants were grown in containers filled with ES soil and where a lateral portion of the containers was additionally supplied with a range of different P concentrations. In the

  5. Phosphate reactivity in long-term poultry litter-amended southern Delaware sandy soils

    USGS Publications Warehouse

    Arai, Y.; Livi, K.J.T.; Sparks, D.L.

    2005-01-01

    Eutrophication caused by dissolved P from poultry litter (PL)-amended agricultural soils has been a serious environmental concern in the Delaware-Maryland-Virginia Peninsula (Delmarva), USA. To evaluate state and federal nutrient management strategies for reducing the environmental impact of soluble P from long-term PL-amended Delaware (DE) soils, we investigated (i) inorganic P speciation; (ii) P adsorption capacity; and (iii) the extent of P desorption. Although the electron microprobe (EMP) analyses showed a strong correlation between P and Al/Fe, crystalline Al/Fe-P precipitates were not detected by x-ray diffraction (XRD). Instead, the inorganic P fractionation analyses showed high levels of oxalate extractable P, Al, and Fe fractions (615-858, 1215-1478, and 337-752 mg kg-1, respectively), which were susceptible to slow release during the long-term (30-d) P desorption experiments at a moderately acidic soil pHwater. The labile P in the short-term (24-h) desorption studies was significantly associated with oxalate and F extractable Fe and Al, respectively. This was evident in an 80% reduction maximum in total desorbable P from NH4 oxalate/F pretreated soils. In the adsorption experiments, P was strongly retained in soils at near targeted pH of lime (???6.0), but P adsorption gradually decreased with decreasing pH near the soil pHwater (???5.0). The overall findings suggest that P losses from the can be suppressed by an increase in the P retention capacity of soils via (i) an increase in the number of lime applications to maintain soil pHwater at near targeted pH values, and/or (ii) alum/iron sulfate amendments to provide additional Al- and Fe-based adsorbents. ?? Soil Science Society of America.

  6. Cumulative effects of sewage sludge and effluent mixture application on soil properties of a sandy soil under a mixture of star and kikuyu grasses in Zimbabwe

    NASA Astrophysics Data System (ADS)

    Madyiwa, S.; Chimbari, M.; Nyamangara, J.; Bangira, C.

    Although sewage effluent and sludge provides nutrients for plant growth, its continual use over extended periods can result in the accumulation of heavy metals in soils and in grass to levels that are detrimental to the food chain. This study was carried in 2001 out at Firle farm, owned by the Municipality of Harare, to assess heavy metal loading on a sandy soil and uptake of the metals by pasture grass consisting of a mixture of Cynodon nlemfuensis (star grass) and Pennisetum clandestinum Chiov (kikuyu grass) following sewage effluent and sludge application for 29 years. Firle Farm receives treated effluent and sludge emanating from domestic and industrial sources. Soil and grass samples were taken from the study area, consisting of 3 ha of non-irrigated area (control) and 1.3 ha of irrigated area. Both the soil and grass samples were tested for Cu, Zn, Ni and Pb using atomic absorption spectrophotometry. Sewage sludge addition resulted in high levels of soil pollution, especially in the 20 cm horizon, in the irrigated area when compared to the control. Grasses took up moderate levels of Cu and Zn, and limited levels of Pb. Nickel was not detectable in grasses despite high levels in the irrigated soil. Copper uptake was several times higher than the suggested potentially toxic level of 12 mg/kg [Soil Science Society of America, Micronutrients in agriculture, second ed., Wisconsin, USA, 1991]. Lead uptake averaged 1.0 mg/kg, which was below 10 mg/kg the suggested limit for agronomic crops [E.M. Seaker, Zinc, copper, cadmium and lead in minespoil, water and plants from reclaimed mine land amended with sewage sludge, 1991]. Cu and Zn showed relatively higher mobility down the soil profile than Ni and Pb. Even then, the concentrations in the lower soil layers were very small, suggesting that the metals were unlikely to contaminate groundwater. There was no direct correlation between metal levels in soils and grasses. It was postulated that it is the bio

  7. Efficacy of biosolids in assisted phytostabilization of metalliferous acidic sandy soils with five grass species.

    PubMed

    Kacprzak, Malgorzata; Grobelak, Anna; Grosser, Anna; Prasad, M N V

    2014-01-01

    The role of sewage sludge as an immobilising agent in the phytostabilization of metal-contaminated soil was evaluated using five grass species viz., Dactylis glomerata L., Festuca arundinacea Schreb., F. rubra L., Lolium perenne L., L. westerwoldicum L. The function of metal immobilization was investigated by monitoring pH, Eh and Cd, Pb, and Zn levels in column experiment over a period of 5-months. Grasses grown on sewage sludge-amendments produced high biomass in comparison to controls. A significant reduction in metal uptake by plants was also observed as a result of sewage sludge application, which was attributed to decreased bioavailability through soil stabilisation. We have observed that the sludge amendment decreased metal bioavailability and concentrations in soil at a depth of 25 cm, in contrast to untreated columns, where metal concentrations in the soil solution were very high. PMID:24912245

  8. Efficacy of Biosolids in Assisted Phytostabilization of Metalliferous Acidic Sandy Soils with Five Grass Species

    PubMed Central

    Kacprzak, Malgorzata; Grobelak, Anna; Grosser, Anna; Prasad, M. N. V.

    2013-01-01

    The role of sewage sludge as an immobilising agent in the phytostabilization of metal-contaminated soil was evaluated using five grass species viz., Dactylis glomerata L., Festuca arundinacea Schreb., F. rubra L., Lolium perenne L., L. westerwoldicum L. The function of metal immobilization was investigated by monitoring pH, Eh and Cd, Pb, and Zn levels in column experiment over a period of 5-months. Grasses grown on sewage sludge-amendments produced high biomass in comparison to controls. A significant reduction in metal uptake by plants was also observed as a result of sewage sludge application, which was attributed to decreased bioavailability through soil stabilisation. We have observed that the sludge amendment decreased metal bioavailability and concentrations in soil at a depth of 25 cm, in contrast to untreated columns, where metal concentrations in the soil solution were very high. PMID:24912245

  9. Orthophosphate Leaching in St. Augustinegrass and Zoysiagrass Grown in Sandy Soil under Field Conditions.

    PubMed

    Gonzalez, Ronald F; Sartain, Jerry B; Kruse, Jason K; Obreza, Thomas A; O'Connor, George A; Harris, Willie G

    2013-01-01

    Phosphorus (P) is required to maintain healthy, high-quality, warm-season turf. However, excessive P applications to soils with poor P retention capabilities may lead to leaching losses to groundwater. This field study was conducted to determine the maximum P fertilizer application rate to (Walt.) [Kuntze] 'Floratam' St. Augustinegrass (St. Augustinegrass) and 'Empire' zoysiagrass (zoysiagrass) below which P leaching is minimized. Five P levels ranging from 0 to 5.0 g P m yr were surface applied as triple superphosphate. Turf was established on an uncoated, low-P sand with negligible P retention capacity. Leaf and root growth, tissue P concentration, soil P concentration, soil P saturation, leachate volume, and orthophosphate (P) concentration in leachates were measured. Mehlich 1-extractable soil P (M1-P) and soil P saturation ratio (PSR) increased with time as the P rate increased. Lower M1-P and PSR values were measured with St. Augustinegrass, which absorbed more P than did zoysiagrass. The root system of St. Augustinegrass was larger and deeper compared with zoysiagrass, promoting greater P uptake and less P leaching. If tissue analysis indicates that P fertilization is required and the soil has the capacity to retain additional P, application of 0.8 g P m yr to zoysiagrass and 1.07 g P m yr to St. Augustinegrass is appropriate and does not result in increased P leaching. PMID:23673941

  10. Effects of degree of water saturation on dispersivity and immobile water in sandy soil columns

    NASA Astrophysics Data System (ADS)

    Maraqa, Munjed A.; Wallace, Roger B.; Voice, Thomas C.

    1997-03-01

    Three natural nonaggregated soil samples, with similar grain-size distributions, have been used to determine the dispersive behavior of porous media under steady, saturated and unsaturated flow conditions. Tritium was used as a tracer and was found to have no sorption on the solid matrix. Generated breakthrough curves (BTCs) for the unsaturated experiments were symmetrical with no evidence of tailing. The unsaturated experiments for two of the soils were adequately described by considering all the water in the pore volume as mobile. However, about 10% of the pore water, independent of the degree of saturation, was found to be immobile in the case of the third soil during unsaturated flow. For this soil, there was no mass transfer between the two water regions, indicating that the immobile water is essentially isolated from the flowing water fraction. For all three soils, dispersivity under unsaturated conditions was found to be higher, independent of the degree of water saturation, than the value determined for the saturated experiments. This is inconsistent with what would be expected from the simple bundle-of-capillary-tubes model and does not agree well with a more sophisticated conceptualization of the porous medium. The data, however, clearly indicate a wider range in pore-water velocities when these soils are desaturated.

  11. Sensitivity of water stress in a two-layered sandy grassland soil to variations in groundwater depth and soil hydraulic parameters

    NASA Astrophysics Data System (ADS)

    Rezaei, M.; Seuntjens, P.; Joris, I.; Boënne, W.; Van Hoey, S.; Campling, P.; Cornelis, W. M.

    2016-01-01

    Monitoring and modelling tools may improve irrigation strategies in precision agriculture. We used non-invasive soil moisture monitoring, a crop growth and a soil hydrological model to predict soil water content fluctuations and crop yield in a heterogeneous sandy grassland soil under supplementary irrigation. The sensitivity of the soil hydrological model to hydraulic parameters, water stress, crop yield and lower boundary conditions was assessed after integrating models. Free drainage and incremental constant head conditions were implemented in a lower boundary sensitivity analysis. A time-dependent sensitivity analysis of the hydraulic parameters showed that changes in soil water content are mainly affected by the soil saturated hydraulic conductivity Ks and the Mualem-van Genuchten retention curve shape parameters n and α. Results further showed that different parameter optimization strategies (two-, three-, four- or six-parameter optimizations) did not affect the calculated water stress and water content as significantly as does the bottom boundary. In this case, a two-parameter scenario, where Ks was optimized for each layer under the condition of a constant groundwater depth at 135-140 cm, performed best. A larger yield reduction, and a larger number and longer duration of stress conditions occurred in the free drainage condition as compared to constant boundary conditions. Numerical results showed that optimal irrigation scheduling using the aforementioned water stress calculations can save up to 12-22 % irrigation water as compared to the current irrigation regime. This resulted in a yield increase of 4.5-6.5 %, simulated by the crop growth model.

  12. Persistence of fensulfothion in a sandy-loam soil and uptake by rutabagas, carrots and radishes using microplots

    SciTech Connect

    Greenhalgh, R.; Read, D.C.

    1981-01-01

    Field microplots were treated with 141 and 282 ppm fensulfothion and 37.1 and 74.2 ppm fensulfothion sulfone. These concentrations are equivalent to field treatment rates of 8.48 and 16.96 kg AI/ha, fensulfothion, and 2.23 and 4.47 kg AI/ha, fensulfothion sulfone, respectively, for banded application (10 cm wide, rows 80 cm apart). The half-lives in a sandy loam soil were 30-39 and 14-23 days, respectively. Fensulfothion sulfone and sulfide were the main derivatives found in fensulfothion treated soil. The maximum levels of these derivatives were 21.22 and 22.95 ppm, respectively for the 8.48 kg/ha treatment and 33.90 and 42.45 ppm, respectively, for the higher treatment, which occurred between 30-60 days. Carrots appeared to take up more fensulfothion from soil than rutabagas or radishes. The residue levels at harvest decreased in the order carrot peel greater than pulp greater than rutabagas root greater than peel greater than pulp. Residue levels of fensulfothion and sulfone in radishes were similar to those found in rutabagas. The ratio sulfoxide/sulfone in rutabagas ranged from 0.4-1.5 and in carrots from 1.7-7.6. This phenomenon is thought to be due to oxidative enzyme systems present in rutabagas. Dimethyl phosphorothioic acid, but not dimethyl phosphoric acid was detected (max. 1.33 ppm) in some rutabagas samples but not in carrots.

  13. A rapid in situ respiration test for measuring aerobic biodegradation rates of hydrocarbons in soil.

    PubMed

    Hinchee, R E; Ong, S K

    1992-10-01

    An in situ test method to measure the aerobic biodegradation rates of hydrocarbons in contaminated soil is presented. The test method provides an initial assessment of bioventing as a remediation technology for hydrocarbon-contaminated soil. The in situ respiration test consists of ventilating the contaminated soil of the unsaturated zone with air and periodically monitoring the depletion of oxygen (O2) and production of carbon dioxide (CO2) over time after the air is turned off. The test is simple to implement and generally takes about four to five days to complete. The test was applied at eight hydrocarbon-contaminated sites of different geological and climatic conditions. These sites were contaminated with petroleum products or petroleum fuels, except for two sites where the contaminants were primarily polycyclic aromatic hydrocarbons. Oxygen utilization rates for the eight sites ranged from 0.02 to 0.99 percent O2/hour. Estimated biodegradation rates ranged from 0.4 to 19 mg/kg of soil/day. These rates were similar to the biodegradation rates obtained from field and pilot studies using mass balance methods. Estimated biodegradation rates based on O2 utilization were generally more reliable (especially for alkaline soils) than rates based on CO2 production. CO2 produced from microbial respiration was probably converted to carbonate under alkaline conditions.

  14. Pyrosequence analysis of bacterial communities in aerobic bioreactors treating polycyclic aromatic hydrocarbon-contaminated soil

    PubMed Central

    Richardson, Stephen D.; Aitken, Michael D.

    2011-01-01

    Two aerobic, lab-scale, slurry-phase bioreactors were used to examine the biodegradation of polycyclic aromatic hydrocarbons (PAHs) in contaminated soil and the associated bacterial communities. The two bioreactors were operated under semi-continuous (draw-and-fill) conditions at a residence time of 35 days, but one was fed weekly and the other monthly. Most of the quantified PAHs, including high-molecular-weight compounds, were removed to a greater extent in the weekly-fed bioreactor, which achieved total PAH removal of 76%. Molecular analyses, including pyrosequencing of 16S rRNA genes, revealed significant shifts in the soil bacterial communities after introduction to the bioreactors and differences in the abundance and types of bacteria in each of the bioreactors. The weekly-fed bioreactor displayed a more stable bacterial community with gradual changes over time, whereas the monthly-fed bioreactor community was less consistent and may have been more strongly influenced by the influx of untreated soil during feeding. Phylogenetic groups containing known PAH-degrading bacteria previously identified through stable-isotope probing of the untreated soil were differentially affected by bioreactor conditions. Sequences from members of the Acidovorax and Sphingomonas genera, as well as the uncultivated ‘‘Pyrene Group 2’’ were abundant in the bioreactors. However, the relative abundances of sequences from the Pseudomonas, Sphingobium, and Pseudoxanthomonas genera, as well as from a group of unclassified anthracene degraders, were much lower in the bioreactors compared to the untreated soil. PMID:21369833

  15. [Dynamic changes of surface soil organic carbon and light-fraction organic carbon after mobile dune afforestation with Mongolian pine in Horqin Sandy Land].

    PubMed

    Shang, Wen; Li, Yu-qiang; Wang, Shao-kun; Feng, Jing; Su, Na

    2011-08-01

    This paper studied the dynamic changes of surface (0-15 cm) soil organic carbon (SOC) and light-fraction organic carbon (LFOC) in 25- and 35-year-old sand-fixing Mongolian pine (Pinus sylvestris var. mongolica) plantations in Horqin Sandy Land, with a mobile dune as a comparison site. After the afforestation on mobile dune, the content of coarse sand in soil decreased, while that of fine sand and clay-silt increased significantly. The SOC and LFOC contents also increased significantly, but tended to decrease with increasing soil depth. Afforestation increased the storages of SOC and LFOC in surface soil, and the increment increased with plantation age. In the two plantations, the increment of surface soil LFOC storage was much higher than that of SOC storage, suggesting that mobile dune afforestation had a larger effect on surface soil LFOC than on SOC.

  16. Sorption-desorption of indaziflam and its three metabolites in sandy soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Indaziflam is a relatively new herbicide for which sorption-desorption information is lacking, and nothing is available on its metabolites. Information is needed on the multiple soil and pesticide characteristics known to influence these processes. Freundlich sorption isotherm slopes were < 1, there...

  17. Evaluation of factors affecting nitrous oxide emission and N transformation in a sandy loam soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A better understanding of the complex factors affecting nitrous oxide (N2O) emission and potential mitigation practices will assist in developing strategies to improve the sustainability of agricultural production systems. Using surface soil collected from a pomegranate orchard, a series of laborato...

  18. Clinoptilolite zeolite influence on inorganic nitrogen in silt loam and sandy agricultural soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development of best management practices can help improve inorganic nitrogen (N) availability to plants and reduce nitrate-nitrogen (NO3-N) leaching in soils. This study was conducted to determine the influence of the zeolite mineral Clinoptilolite (CL) additions on NO3-N and ammonium-nitrogen (NH4...

  19. Clinoptilolite Zeolite Influence on Inorganic Nitrogen in Silt Loam and Sandy Agricultural Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development of best management practices can help improve inorganic nitrogen (N) availability to plants and reduce nitrate-nitrogen (NO3-N) leaching in soils. This study was conducted to determine the influence of the zeolite mineral Clinoptilolite (CL) additions on NO3-N and ammonium-nitrogen (NH4...

  20. Clinoptilolite zeolite influence on nitrogen in a manure-amended sandy agricultural soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Development of best management practices can help improve inorganic nitrogen (N) availability to plants and reduce nitrate-nitrogen (NO3-N) leaching in soils. This study was conducted to determine the influence of the zeolite mineral clinoptilolite (CL) additions on NO3-N and ammonium-nitrogen (NH4-...

  1. Soil organic carbon and total nitrogen responses after 34 years of tillage of a sandy ultisol

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conservation tillage and crop management strategies are available to increase soil organic carbon (SOC) and total nitrogen (TN) contents, but long-term (> 30 yrs) field results quantifying these increases are sparse. Our objectives were to quantity above ground biomass inputs and changes in vertica...

  2. Norflurazon mobility, dissipation, activity, and persistence in a sandy soil as influenced by formulation.

    PubMed

    Sopeña, Fátima; Maqueda, Celia; Morillo, Esmeralda

    2007-05-01

    Five ethylcellulose (EC) microencapsulated formulations (MEFs) of norflurazon were prepared and applied in soil to study their mobility, dissipation, activity, and persistence. The results show that the release into water of norflurazon from EC microspheres was retarded when compared with that of commercial herbicide. The mobility of norflurazon from MEFs into soil columns has been greatly diminished in comparison with that of its current commercial formulation (CF). Norflurazon distribution at different depths in the soil was higher in the upper ring (up to 50% of the initial application). In contrast, the residues from commercial norflurazon along the complete soil column were only about 2%. Degradation and bioassay experiments showed that the MEFs had greater persistence (t1/2 values were 7.72 and 30.83 weeks for CF and MEFs, respectively) and herbicidal activity than the commercial formulation. The use of these formulations can be advantageous, because they can minimize the risk of groundwater contamination and permit herbicide use at reduced rates, maintaining the desired concentrations of herbicide in the topsoil layer for longer periods of weed control.

  3. Draft Genome Sequence of Jeotgalibacillus soli DSM 23228, a Bacterium Isolated from Alkaline Sandy Soil

    PubMed Central

    Chan, Kok-Gan; Yaakop, Amira Suriaty; Chan, Chia Sing; Ee, Robson; Tan, Wen-Si; Gan, Han Ming

    2015-01-01

    Jeotgalibacillus soli, a bacterium capable of degrading N-acyl homoserine lactone, was isolated from a soil sample in Portugal. J. soli constitutes the only Jeotgalibacillus species isolated from a non-marine source. Here, the draft genome, several interesting glycosyl hydrolases, and its putative N-acyl homoserine lactonases are presented. PMID:25999554

  4. Modelling Furrow Irrigation-Induced Erosion on a Sandy Loam Soil in Samaru, Northern Nigeria

    PubMed Central

    Dibal, Jibrin M.; Igbadun, H. E.; Ramalan, A. A.; Mudiare, O. J.

    2014-01-01

    Assessment of soil erosion and sediment yield in furrow irrigation is limited in Samaru-Zaria. Data was collected in 2009 and 2010 and was used to develop a dimensionless model for predicting furrow irrigation-induced erosion (FIIE) using the dimensional analyses approach considering stream size, furrow length, furrow width, soil infiltration rate, hydraulic shear stress, soil erodibility, and time flow of water in the furrows as the building components. One liter of water-sediment samples was collected from the furrows during irrigations from which sediment concentrations and soil erosion per furrow were calculated. Stream sizes Q (2.5, 1.5, and 0.5 l/s), furrow lengths X (90 and 45 m), and furrow widths W (0.75 and 0.9 m) constituted the experimental factors randomized in a split plot design with four replications. Water flow into and out of the furrows was measured using cutthroat flumes. The model produced reasonable predictions relative to field measurements with coefficient of determination R 2 in the neighborhood of 0.8, model prediction efficiency NSE (0.7000), high index of agreement (0.9408), and low coefficient of variability (0.4121). The model is most sensitive to water stream size. The variables in the model are easily measurable; this makes it better and easily adoptable. PMID:27471748

  5. Soil C dynamics in a 26-year CRP chronosequence on an Amarillo fine sandy loam

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Conservation Reserve Program (CRP) sequesters more carbon (C) on private lands than any other federally administered program, but the rate and maximum amount of sequestered SOC is dependent on inherent soil properties (e.g. texture), local climate, and initial restoration efforts. We estimated t...

  6. Soil disturbance alters plant community composition and decreases mycorrhizal carbon allocation in a sandy grassland.

    PubMed

    Schnoor, Tim Krone; Mårtensson, Linda-Maria; Olsson, Pål Axel

    2011-11-01

    We have studied how disturbance by ploughing and rotavation affects the carbon (C) flow to arbuscular mycorrhizal (AM) fungi in a dry, semi-natural grassland. AM fungal biomass was estimated using the indicator neutral lipid fatty acid (NLFA) 16:1ω5, and saprotrophic fungal biomass using NLFA 18:2ω6,9. We labeled vegetation plots with (13)CO(2) and studied the C flow to the signature fatty acids as well as uptake and allocation in plants. We found that AM fungal biomass in roots and soil decreased with disturbance, while saprotrophic fungal biomass in soil was not influenced by disturbance. Rotavation decreased the (13)C enrichment in NLFA 16:1ω5 in soil, but (13)C enrichment in the AM fungal indicator NLFA 16:1ω5 in roots or soil was not influenced by any other disturbance. In roots, (13)C enrichment was consistently higher in NLFA 16:1ω5 than in crude root material. Grasses (mainly Festuca brevipila) decreased as a result of disturbance, while non-mycorrhizal annual forbs increased. This decreases the potential for mycorrhizal C sequestration and may have been the main reason for the reduced mycorrhizal C allocation found in disturbed plots. Disturbance decreased the soil ammonium content but did not change the pH, nitrate or phosphate availability. The overall effect of disturbance on C allocation was that more of the C in AM fungal mycelium was directed to the external phase. Furthermore, the functional identity of the plants seemed to play a minor role in the C cycle as no differences were seen between different groups, although annuals contained less AM fungi than the other groups.

  7. Fate of carbosulfan and monocrotophos in sandy loam soils of Pakistan under field conditions at different watertable depths.

    PubMed

    Tariq, Muhammad Ilyas; Afzal, Shahzad; Shahzad, Farina

    2010-05-01

    Information regarding pesticide mobility is critical for the evaluation of pesticide management practices. For this purpose, lysimetric studies were conducted to develop assessment schemes to protect groundwater from unacceptable effects caused by pesticide use. By using these studies, specific monitoring actions and prevention measures for the protection of waters can be studied, and the results thus obtained can provide the local authorities and the decision makers with an identification tool for demarcating risk areas. Pesticide residues were found at the bottom of lysimeters in the following pattern i.e., 1.52 > 2.1 > 2.74 m which could represent an "index of risk" for groundwater pollution. Regressions built for carbofuran and monocrotophos against watertable depths showed a decreasing trend of pesticide in higher watertable treatments. These findings support the existence of a significant role for chromatographic flow in sandy texture soil. Moreover, the higher values of pesticide residue at the bottom of lysimeters reflect that chromatographic flow as well as preferential flow pattern prevails during higher precipitation events. The precipitation received during the study was higher than the 10 year average and can be considered relatively as a worst case scenario. Finally, the authors have recommended a standardized pesticide monitoring scheme for groundwater in accordance with the already validated generic schemes in developed countries. PMID:21491630

  8. Fate of carbosulfan and monocrotophos in sandy loam soils of Pakistan under field conditions at different watertable depths.

    PubMed

    Tariq, Muhammad Ilyas; Afzal, Shahzad; Shahzad, Farina

    2010-05-01

    Information regarding pesticide mobility is critical for the evaluation of pesticide management practices. For this purpose, lysimetric studies were conducted to develop assessment schemes to protect groundwater from unacceptable effects caused by pesticide use. By using these studies, specific monitoring actions and prevention measures for the protection of waters can be studied, and the results thus obtained can provide the local authorities and the decision makers with an identification tool for demarcating risk areas. Pesticide residues were found at the bottom of lysimeters in the following pattern i.e., 1.52 > 2.1 > 2.74 m which could represent an "index of risk" for groundwater pollution. Regressions built for carbofuran and monocrotophos against watertable depths showed a decreasing trend of pesticide in higher watertable treatments. These findings support the existence of a significant role for chromatographic flow in sandy texture soil. Moreover, the higher values of pesticide residue at the bottom of lysimeters reflect that chromatographic flow as well as preferential flow pattern prevails during higher precipitation events. The precipitation received during the study was higher than the 10 year average and can be considered relatively as a worst case scenario. Finally, the authors have recommended a standardized pesticide monitoring scheme for groundwater in accordance with the already validated generic schemes in developed countries.

  9. Nitrogen mineralization and transformation from composts and biosolids during field incubation in a sandy soil

    SciTech Connect

    He, Z.L.; Alva, A.K.; Yan, P.; Li, Y.C.; Calvert, D.V.; Stoffella, P.J.; Banks, D.J.

    2000-02-01

    Field evaluation of nutrient release from composts is important to estimate nutrient contribution to crops, potential leaching of nutrients, and, ultimately, to determine optimum application rates, timing, and placement of composts. Field incubation and laboratory analyses were conducted to evaluate the mineralization rate and transformation of N in biosolids (BSD), yard waste (YW), and West Palm Beach co-compost (WPCC). Each of the composts or biosolids was packed into PVC columns and inserted vertically into the upper layer of an Oldsmar fine sand of raised citrus beds. The top end of the PVC column was capped to prevent excessive leaching of nutrients from the columns. The moisture equilibrium between the incubated sample and the soil in the field was attained through the bottom and four side holes of each column, which were separated from the contacting soil by 400-mesh nylon screen. A set of the incubated columns was removed at monthly intervals, and the soil underlying each column was sampled to analyze for KCl-extractable NH{sub 4}-N and NO{sub 3}-N. Total C and N of the incubated samples were determined at the end of the 1-year incubation.

  10. Imaging saline tracer infiltration into unsaturated sandy soil using full-waveform inversion of cross-borehole ground penetrating radar

    NASA Astrophysics Data System (ADS)

    Looms, M. C.; Haarder, E. B.; Keskinen, J.; Nielsen, L.; Van Der Kruk, J.; Klotzsche, A.

    2015-12-01

    Cross-borehole ground penetrating radar (GPR) can provide high-resolution (tens of centimeter) information of the subsurface between boreholes located 5-10 m apart. The method is minimal invasive and therefore provides a unique opportunity to image subsurface variability not possible with standard point-scale equipment, such as TDR- and/or capacitance probes. Full-waveform inversion (FWI) of cross-borehole GPR uses the entire waveform of the transmitted electromagnetic signal. The recorded data contains information on the travel time of the pulse, as well as the attenuation, resulting in moisture content and electrical conductivity images of the subsurface using just one method. Few case studies of cross-borehole GPR FWI using real data have been published to date. The majority of these studies focus on estimating the variation in porosity in the saturated zone (e.g. in gravel aquifers, fractured metamorphic rock, and heterogeneous chalk sediments). In this study, we use cross-borehole GPR to monitor the infiltration of a saline tracer into an unsaturated sandy soil. In September 2011, saline water was added across a 142 m2 area at an agricultural field site in Denmark. A total of 3.3 mm saline water was applied mimicking a natural infiltration event. During the following year, the tracer infiltration into the subsurface was monitored using cross-borehole GPR at weekly to monthly intervals. Furthermore, five cores were extracted within the field site to obtain independent profiles of soil moisture and pore water conductivity for comparison. The cross-borehole GPR data were inverted using ray-based and FWI techniques. For the FWI an appropriate starting model and an effective wavelet must be estimated. Preliminary results indicate that the data modeled for the FWI results mimic better the measured data compared to the ray-based results. However, more research is needed to investigate the influence of the used starting model and the effective wavelet estimation.

  11. Effect of rainfall and tillage direction on the evolution of surface crusts, soil hydraulic properties and runoff generation for a sandy loam soil

    NASA Astrophysics Data System (ADS)

    Ndiaye, Babacar; Esteves, Michel; Vandervaere, Jean-Pierre; Lapetite, Jean-Marc; Vauclin, Michel

    2005-06-01

    The study was aimed at evaluating the effect of rainfall and tillage-induced soil surface characteristics on infiltration and runoff on a 2.8 ha catchment located in the central region of Senegal. This was done by simulating 30 min rain storms applied at a constant rate of about 70 mm h -1, on 10 runoff micro-plots of 1 m 2, five being freshly harrowed perpendicularly to the slope and five along the slope (1%) of the catchment. Runoff was automatically recorded at the outlet of each plot. Hydraulic properties such as capillary sorptivity and hydraulic conductivity of the sandy loam soil close to saturation were determined by running 48 infiltration tests with a tension disc infiltrometer. That allowed the calculation of a mean characteristic pore size hydraulically active and a time to ponding. Superficial water storage capacity was estimated using data collected with an electronic relief meter. Because the soil was subject to surface crusting, crust-types as well as their spatial distribution within micro-plots and their evolution with time were identified and monitored by taking photographs at different times after tillage. The results showed that the surface crust-types as well as their tillage dependent dynamics greatly explain the decrease of hydraulic conductivity and sorptivity as the cumulative rainfall since tillage increases. The exponential decaying rates were found to be significantly greater for the soil harrowed along the slope (where the runoff crust-type covers more than 60% of the surface after 140 mm of rain) than across to the slope (where crusts are mainly of structural (60%) and erosion (40%) types). That makes ponding time smaller and runoff more important. Also it was shown that soil hydraulic properties after about 160 mm of rain were close to those of untilled plot not submitted to any rain. That indicates that the effects of tillage are short lived.

  12. Distinct effects of moisture and air contents on acoustic properties of sandy soil.

    PubMed

    Oshima, Takuya; Hiraguri, Yasuhiro; Okuzono, Takeshi

    2015-09-01

    Knowledge of distinct effects of moisture content and air volume on acoustic properties of soil is sought to predict the influence of human activities such as cultivation on acoustic propagation outdoors. This work used an impedance tube with the two-thickness method to investigate such effects. For a constant moisture weight percentage, the magnitude of the characteristic impedance became smaller and the absorption coefficient became higher with increase of the air space ratio. For a constant air space ratio, the absorption coefficient became larger and the magnitude of the propagation constant became smaller with increasing moisture weight percentage. PMID:26428823

  13. [Mechanisms of grass in slope erosion control in Loess sandy soil region of Northwest China].

    PubMed

    Zhao, Chun-Hong; Gao, Jian-En; Xu, Zhen

    2013-01-01

    By adopting the method of simulated precipitation and from the viewpoint of slope hydrodynamics, in combining with the analysis of soil resistance to erosion, a quantitative study was made on the mechanisms of grass in controlling the slope erosion in the cross area of wind-water erosion in Loess Plateau of Northwest China under different combinations of rainfall intensity and slope gradient, aimed to provide basis to reveal the mechanisms of vegetation in controlling soil erosion and to select appropriate vegetation for the soil and water conservation in Loess Plateau. The grass Astragalus adsurgens with the coverage about 40% could effectively control the slope erosion. This grass had an efficiency of more than 70% in reducing sediment, and the grass root had a greater effect than grass canopy. On bare slope and on the slopes with the grass plant or only the grass root playing effect, there existed a functional relation between the flow velocity on the slopes and the rainfall intensity and slope gradient (V = DJ(0.33 i 0.5), where V is flow velocity, D is the comprehensive coefficient which varies with different underlying surfaces, i is rainfall intensity, and J is slope gradient). Both the grass root and the grass canopy could markedly decrease the flow velocity on the slopes, and increase the slope resistance, but the effect of grass root in decreasing flow velocity was greater while the effect in increasing resistance was smaller than that of grass canopy. The effect of grass root in increasing slope resistance was mainly achieved by increasing the sediment grain resistance, while the effect of canopy was mainly achieved by increasing the slope form resistance and wave resistance. The evaluation of the soil resistance to erosion by using a conceptual model of sediment generation by overland flow indicated that the critical shear stress value of bare slope and of the slopes with the grass plant or only the grass root playing effect was 0.533, 1.672 and 0

  14. Water quality and surfactant effects on the water repellency of a sandy soil

    NASA Astrophysics Data System (ADS)

    Lehrsch, G. A.; Sojka, R. E.

    2011-06-01

    SummaryDifferences in irrigation water quality may affect the water repellency of soils treated or untreated with surfactants. Using simulated irrigations, we evaluated water quality and surfactant application rate effects upon the water repellency of a Quincy sand (Xeric Torripsamment). We used a split plot design with two irrigation water qualities, three surfactant application rates, two irrigations, and 12 sampling depths as fixed effects, with four replications. Each water quality × rate × irrigation combination was a main plot and depth was a repeated-measures subplot. A slightly water repellent Quincy soil (average water drop penetration time, WDPT, of 2.5 s) was packed in 25-mm lifts (or layers) to a bulk density of 1.6 Mg m -3 into 0.15-m-high × 0.105-m-diameter plastic columns. We studied a nonionic surfactant, a blend of an ethylene oxide/propylene oxide block copolymer and an alkyl polyglycoside. We sprayed the surfactant at rates of 0, 9.4, and 46.8 L ha -1, diluted with reverse osmosis water (RW) to apply 187 L ha -1 of solution, onto the soil surface of each packed column. About 1 and 5 days after surfactant application, columns were sprinkler irrigated with either RW or well water (WW). The WDPT was then measured with depth on soil air-dried after the first and after the second irrigation. After the first irrigation, WDPT at depths from 97 to 117 mm averaged across surfactant rates reached a maximum of 28 s, regardless of irrigation water quality. WDPT was greatest at 117 mm with RW but only at 97 mm with WW. After the second irrigation, maximum WDPT was 1202 s at 139 mm with RW but only 161 s at 117 mm with WW, nearly 7.5 fold less than with RW. WDPT was greatest near the wetting front, irrespective of water quality. We conclude that irrigation water containing modest amounts of electrolytes or salts, in this case mostly salts of Ca 2+, reduces water repellency in the presence or absence of surfactant. Our experimental results may also help

  15. [Mechanisms of grass in slope erosion control in Loess sandy soil region of Northwest China].

    PubMed

    Zhao, Chun-Hong; Gao, Jian-En; Xu, Zhen

    2013-01-01

    By adopting the method of simulated precipitation and from the viewpoint of slope hydrodynamics, in combining with the analysis of soil resistance to erosion, a quantitative study was made on the mechanisms of grass in controlling the slope erosion in the cross area of wind-water erosion in Loess Plateau of Northwest China under different combinations of rainfall intensity and slope gradient, aimed to provide basis to reveal the mechanisms of vegetation in controlling soil erosion and to select appropriate vegetation for the soil and water conservation in Loess Plateau. The grass Astragalus adsurgens with the coverage about 40% could effectively control the slope erosion. This grass had an efficiency of more than 70% in reducing sediment, and the grass root had a greater effect than grass canopy. On bare slope and on the slopes with the grass plant or only the grass root playing effect, there existed a functional relation between the flow velocity on the slopes and the rainfall intensity and slope gradient (V = DJ(0.33 i 0.5), where V is flow velocity, D is the comprehensive coefficient which varies with different underlying surfaces, i is rainfall intensity, and J is slope gradient). Both the grass root and the grass canopy could markedly decrease the flow velocity on the slopes, and increase the slope resistance, but the effect of grass root in decreasing flow velocity was greater while the effect in increasing resistance was smaller than that of grass canopy. The effect of grass root in increasing slope resistance was mainly achieved by increasing the sediment grain resistance, while the effect of canopy was mainly achieved by increasing the slope form resistance and wave resistance. The evaluation of the soil resistance to erosion by using a conceptual model of sediment generation by overland flow indicated that the critical shear stress value of bare slope and of the slopes with the grass plant or only the grass root playing effect was 0.533, 1.672 and 0

  16. Parameterization of albedo, thermal inertia, and surface roughness of desert scrub/sandy soil surface

    NASA Technical Reports Server (NTRS)

    Otterman, J.; Mccumber, M.

    1986-01-01

    Spectral albedo, A sub n, for the direct solar beam is defined as A sub n (r sub i,s, theta sub 0) = r sub i exp(-s tan theta sub 0)1-I(s) where I(s) is the integral over all reflection angles describing the interception by the absorbing plants of the flux reflected from the soil, r sub i soil reflectance, assumed Lambertian, S the projection on a vertical plane of plants per unit surface area, and theta sub 0 is the solar zenith angle. Hemispheric reflectance for the direct solar beam equals 1-I(s) times the reflectance to the zenith. The values of s of 0.1, 0.2, and 0.3 respectively quantify sparse, moderately dense, and very dense desert scrub. Thin plants are assumed to be of negligible thermal inertia, and thus directly yield the absorbed insolation to the atmosphere. Surface thermal inertia is therefore effectively reduced. The ratio of surface roughness height to plant height is parameterized for sparse, moderately dense, and very dense desert-scrub as a function of s based on data expressing the dependence of this ratio on plant silhouette.

  17. Dissolution kinetics of high explosives particles in a saturated sandy soil.

    PubMed

    Morley, Matthew C; Yamamoto, Hiroshi; Speitel, Gerald E; Clausen, Jay

    2006-05-30

    Solid phase high explosive (HE) residues from munitions detonation may be a persistent source of soil and groundwater contamination at military training ranges. Saturated soil column tests were conducted to observe the dissolution behavior of individual components (RDX, HMX, and TNT) from two HE formulations (Comp B and C4). HE particles dissolved readily, with higher velocities yielding higher dissolution rates, higher mass transfer coefficients, and lower effluent concentrations. Effluent concentrations were below solubility limits for all components at superficial velocities of 10-50 cm day(-1). Under continuous flow at 50 cm day(-1), RDX dissolution rates from Comp B and C4 were 34.6 and 97.6 microg h(-1) cm(-2) (based on initial RDX surface area), respectively, significantly lower than previously reported dissolution rates. Cycling between flow and no-flow conditions had a small effect on the dissolution rates and effluent concentrations; however, TNT dissolution from Comp B was enhanced under intermittent-flow conditions. A model that includes advection, dispersion, and film transfer resistance was developed to estimate the steady-state effluent concentrations.

  18. Transformation of (14)C-pyrimidynyloxybenzoic herbicide ZJ0273 in aerobic soils.

    PubMed

    Haiyan, Wang; Zhiyang, Yu; Ling, Yue; Ailiang, Han; Yanfei, Zhang; Juying, Li; Qingfu, Ye; Zhengmin, Yang; Long, Lu

    2010-04-15

    A soil metabolism study of propyl 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamino)benzoate (ZJ0273), a novel broad-spectrum herbicide, was carried out using (14)C labeled on two different rings, i.e., [pyrimidine-4,6-(14)C] ZJ0273 and [benzyl-U-(14)C] ZJ0273. Ultralow liquid scintillation counting and LC-MS/MS were used to identify the degradation intermediates and quantify their dynamics in aerobic soils. Four aromatic intermediates, 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamino)benzoic acid (M1), 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzamido)benzoic acid (M2), 2-(4,6-dimethoxypyrimidin-2-yloxy)benzoic acid (M3), and 4,6-dimethoxypyrimidin-2-ol (M4), were identified and their identity was further confirmed against authentic standards. Analysis of metabolites suggested two degradation pathways: (1) Upon loss of the propyl group, M1 was produced via hydrolysis of propyl 4-(2-(4,6-dimethoxypyrimidin-2-yloxy)benzylamino)benzoate after which the C-N bond between rings A and B was cleaved by oxidation and biochemical degradation to yield M3, which was further converted into M4 and finally mineralized to CO(2); and (2) the first step was the same as in pathway 1, but M1 first underwent a carbonylation to form M2. The C-N bond between rings A and B of M2 was cleaved by hydrolysis to yield M3. Dynamic changes in the four metabolites in aerobic soils were also investigated by HPLC coupled analysis of radioactivity of isolated peaks. After a 100-day incubation, 1.7-9.7% of applied (14)C was found as M1, 0.3-1.1% as M2, 14.5-20.9% as M3, and 3.7-6.7% as M4 in the soils, and pH appeared to be the most influential soil property affecting the formation and dissipation of these metabolites.

  19. Hydrodispersive characterization of a sandy porous medium by tracer tests carried out in laboratory on undisturbed soil samples

    NASA Astrophysics Data System (ADS)

    Ferrante, Aldo Pedro; Fallico, Carmine; Rios, Ana C.; Fernanda Rivera, Maria; Santillan, Patricio; Salazar, Mario

    2013-04-01

    The contamination of large areas and correspondent aquifers often imposes to implement some recovery operations which are generally complex and very expensive. Anyway, these interventions necessarily require the preventive characterization of the aquifers to be reclaimed and in particular the knowledge of the relevant hydrodispersive parameters. The determination of these parameters requires the implementation tracer tests for the specific site (Sauty JP, 1978). To reduce cost and time that such test requires tracer tests on undisturbed soil samples, representative of the whole aquifer, can be performed. These laboratory tests are much less expensive and require less time, but the results are certainly less reliable than those obtained by field tests for several reasons, including the particular scale of investigation. In any case the hydrodispersive parameters values, obtained by tests carried out in laboratory, can provide useful information on the considered aquifer, allowing to carry out initial verifications on the transmission and propagation of the pollutants in the aquifer considered. For this purpose, tracer tests with inlet of short time were carried out in the Soil Physics Laboratory of the Department of Soil Protection (University of Calabria), on a series of sandy soil samples with six different lengths, repeating each test with three different water flow velocities (5 m/d; 10 m/s and 15 m/d) (J. Feyen et al., 1998). The lengths of the samples taken into account are respectively 15 cm, 24 cm, 30 cm, 45 cm, 60 cm and 75 cm, while the solution used for each test was made of 100 ml of water and NaCl with a concentration of this substance corresponding to 10 g/L. For the porous medium taken into consideration a particle size analysis was carried out, resulting primarily made of sand, with total porosity equal to 0.33. Each soil sample was placed in a flow cell in which was inlet the tracer from the bottom upwards, measuring by a conductivimeter the

  20. Effect of passivator on Cu form transformation in pig manure aerobic composting and application in soil.

    PubMed

    Lu, Xiao-Ming; Lu, Peng-Zhen; Chen, Jian-Jun; Zhang, Hui; Fu, Jie

    2015-10-01

    A sequential extraction approach was used to evaluate the effects of various combinations of passivators (sepiolite, phosphate rock, and coal fly ash) on the concentration and speciation of Cu in swine manure aerobic compost along with soil to which the compost had been applied. The results indicate that the various passivators altered the bound forms of Cu in pig manure and soil; the concentrations of exchangeable and Fe-Mn-bound Cu decreased, whereas the residual Cu concentration increased, indicating that Cu transformed to low-availability forms after the passivator treatments. The concentrations of the carbonate-bound and organic-bound Cu varied widely. Among all treatments, the treatment of the control + straw + sepiolite + coal fly ash (2.5 %) + phosphate rock (5.0 %) resulted in the most efficient passivation of Cu; the percentage of residual Cu reached 3.91-21.14 %, obviously surpassing the percentage for the control without passivation. The treatment of the control + straw + sepiolite + phosphate rock (2.5 %) resulted in the lowest residual Cu fraction (0.85 %) among passivator treatments. These results show that the addition of suitable combinations of passivators to the composting process reduced the availability of Cu and the risk of Cu pollution during the application of composted pig manure to soil. Passivation also decreased the Cu content of Apium graveolens.

  1. Effect of passivator on Cu form transformation in pig manure aerobic composting and application in soil.

    PubMed

    Lu, Xiao-Ming; Lu, Peng-Zhen; Chen, Jian-Jun; Zhang, Hui; Fu, Jie

    2015-10-01

    A sequential extraction approach was used to evaluate the effects of various combinations of passivators (sepiolite, phosphate rock, and coal fly ash) on the concentration and speciation of Cu in swine manure aerobic compost along with soil to which the compost had been applied. The results indicate that the various passivators altered the bound forms of Cu in pig manure and soil; the concentrations of exchangeable and Fe-Mn-bound Cu decreased, whereas the residual Cu concentration increased, indicating that Cu transformed to low-availability forms after the passivator treatments. The concentrations of the carbonate-bound and organic-bound Cu varied widely. Among all treatments, the treatment of the control + straw + sepiolite + coal fly ash (2.5 %) + phosphate rock (5.0 %) resulted in the most efficient passivation of Cu; the percentage of residual Cu reached 3.91-21.14 %, obviously surpassing the percentage for the control without passivation. The treatment of the control + straw + sepiolite + phosphate rock (2.5 %) resulted in the lowest residual Cu fraction (0.85 %) among passivator treatments. These results show that the addition of suitable combinations of passivators to the composting process reduced the availability of Cu and the risk of Cu pollution during the application of composted pig manure to soil. Passivation also decreased the Cu content of Apium graveolens. PMID:25982987

  2. Remediation of explosive-polluted soil in slurry phase by aerobic biostimulation

    NASA Astrophysics Data System (ADS)

    Xin, Baoping; Shen, Mengyue; Aslam, Hina; Wu, Feng

    2013-06-01

    There is a great volume of polluted soil by 2,4,6-trinitrotoluene (TNT) manufacturing wastewater containing dozen of nitrocompounds in China. In this study, biostimulation was used for remediating the explosive-polluted soil in aerobic bioslurry by monitoring the removal of total organic carbon (TOC). The results showed that the pulp density had almost no effect on TOC removal; whereas the acetone addition evidently improved remediation efficiency of the polluted soil by intrinsic microorganism, and the TOC removal increased from 25% to 38.4% when dose of acetone increased from 0% to 4% (v/v). The maximum TOC removal of 49.1% was achieved through further adjusting pH at 9.0 and temperature at 30 °C. The second order reaction fits well removal dynamics of TOC under the optimum conditions. With the average conditions, liquid phase TOC decreased from 3404 to 3144 mg/L and solid phase TOC dropped from 1022 to 104 mg/L, leading to toxicity decline by 35%; the optimum condition witnessed 48.9% of TOC removal from 4500 to 2300 mg/L in liquid phase, causing toxicity drop by 62%.

  3. Novel aerobic benzene degrading microorganisms identified in three soils by stable isotope probing.

    PubMed

    Xie, Shuguang; Sun, Weimin; Luo, Chunling; Cupples, Alison M

    2011-02-01

    The remediation of benzene contaminated groundwater often involves biodegradation and although the mechanisms of aerobic benzene biodegradation in laboratory cultures have been well studied, less is known about the microorganisms responsible for benzene degradation in mixed culture samples or at contaminated sites. To address this knowledge gap, DNA based stable isotope probing (SIP) was utilized to identify active benzene degraders in microcosms constructed with soil from three sources (a contaminated site and two agricultural sites). For this, replicate microcosms were amended with either labeled (¹³C) or unlabeled benzene and the extracted DNA samples were ultracentrifuged, fractioned and subject to terminal restriction fragment length polymorphism (TRFLP). The dominant benzene degraders (responsible for ¹³C uptake) were determined by comparing relative abundance of TRFLP phylotypes in heavy fractions of labeled benzene (¹³C) amended samples to the controls (from unlabeled benzene amended samples). Two phylotypes (a Polaromonas sp. and an Acidobacterium) were the major benzene degraders in the microcosms constructed from the contaminated site soil, whereas one phylotype incorporated the majority of the benzene-derived ¹³C in each of the agricultural soils ("candidate" phylum TM7 and an unclassified Sphingomonadaceae).

  4. Distribution and efficacy of drip-applied metam-sodium against the survival of Rhizoctonia solani and yellow nutsedge in plastic-mulched sandy soil beds.

    PubMed

    Candole, Byron L; Csinos, Alexander S; Wang, Dong

    2007-05-01

    The effects of metam-sodium application rate on soil residence time, spatial and temporal distributions of methyl isothiocyanate and pest control efficacy were studied in a Georgia sandy soil. Metam-sodium 420 g L(-1) SL was drip applied at rates of 147 and 295 L ha(-1) in plastic-mulched raised beds. Methyl isothiocyanate concentrations in soil air space were monitored from four preselected sites: 10 and 20 cm below the emitter, and 20 and 30 cm laterally away from the emitter at 3, 12, 24, 48, 72, 120 and 240 h after chemigation. A higher rate of metam-sodium application resulted in higher methyl isothiocyanate concentrations in the soil. Highest methyl isothiocyanate concentrations were found at 20 cm below the emitter, and lowest at 30 cm laterally away from the emitter. Methyl isothiocyanate concentrations decreased with time and distance from the emitter. Lower methyl isothiocyanate concentration x time product values at 20 and 30 cm away from the emitter resulted in lower mortalities of Rhizoctonia solani Kühn and yellow nutsedge (Cyperus esculentus L.). The results demonstrated that methyl isothiocyanate can be delivered at lethal doses with drip-applied water downward within the beds. Lateral diffusion of methyl isothiocyanate from the point of application did not reach biologically active concentrations to affect the survival of R. solani or yellow nutsedge. Further studies on the lateral distribution of methyl isothiocyanate in sandy soils are needed to circumvent this limitation. PMID:17397113

  5. Impact of slurry management strategies on potential leaching of nutrients and pathogens in a sandy soil amended with cattle slurry.

    PubMed

    Fangueiro, D; Surgy, S; Napier, V; Menaia, J; Vasconcelos, E; Coutinho, J

    2014-12-15

    For farmers, management of cattle slurry (CS) is now a priority, in order to improve the fertilizer value of the slurry and simultaneously minimize its environmental impact. Several slurry pre-treatments and soil application methods to minimize ammonia emissions are now available to farmers, but the impact of such management strategies on groundwater is still unclear. A laboratory experiment was performed over 24 days in controlled conditions, with undisturbed soil columns (sandy soil) in PVC pipes (30 cm high and 5.7 cm in diameter). The treatments considered (4 replicates) were: a control with no amendment (CTR), injection of whole CS (WSI), and surface application of: whole CS (WSS), acidified (pH 5.5) whole CS (AWSS), the liquid fraction obtained by centrifugation of CS (LFS), and acidified (pH 5.5) liquid fraction (ALFS). An amount of CS equivalent to 240 kg N ha(-1) was applied in all treatments. The first leaching event was performed 72 h after application of the treatments and then leaching events were performed weekly to give a total of four irrigation events (IEs). All the leachates obtained were analyzed for mineral and organic nitrogen, electrical conductivity (EC), pH, total carbon, and phosphorus. Total coliforms and Escherichia coli were also quantified in the leachates obtained in the first IE. The results show that both acidification and separation had significant effects on the composition of the leachates: higher NO3(-) concentrations were observed for the LFS and ALFS relative to all the other treatments, throughout the experiment, and lower NO3(-) concentrations were observed for acidified relative to non-acidified treatments at IE2. Acidification of both the LF and WS led to higher NH4(+) concentrations as well as an increase of EC for treatment ALFS relative to the control, in the first IE, and lower pH values in the AWSS. Furthermore, the E. coli and total coliform concentrations in AWSS, LFS, and ALFS were significantly higher than in

  6. Impact of slurry management strategies on potential leaching of nutrients and pathogens in a sandy soil amended with cattle slurry.

    PubMed

    Fangueiro, D; Surgy, S; Napier, V; Menaia, J; Vasconcelos, E; Coutinho, J

    2014-12-15

    For farmers, management of cattle slurry (CS) is now a priority, in order to improve the fertilizer value of the slurry and simultaneously minimize its environmental impact. Several slurry pre-treatments and soil application methods to minimize ammonia emissions are now available to farmers, but the impact of such management strategies on groundwater is still unclear. A laboratory experiment was performed over 24 days in controlled conditions, with undisturbed soil columns (sandy soil) in PVC pipes (30 cm high and 5.7 cm in diameter). The treatments considered (4 replicates) were: a control with no amendment (CTR), injection of whole CS (WSI), and surface application of: whole CS (WSS), acidified (pH 5.5) whole CS (AWSS), the liquid fraction obtained by centrifugation of CS (LFS), and acidified (pH 5.5) liquid fraction (ALFS). An amount of CS equivalent to 240 kg N ha(-1) was applied in all treatments. The first leaching event was performed 72 h after application of the treatments and then leaching events were performed weekly to give a total of four irrigation events (IEs). All the leachates obtained were analyzed for mineral and organic nitrogen, electrical conductivity (EC), pH, total carbon, and phosphorus. Total coliforms and Escherichia coli were also quantified in the leachates obtained in the first IE. The results show that both acidification and separation had significant effects on the composition of the leachates: higher NO3(-) concentrations were observed for the LFS and ALFS relative to all the other treatments, throughout the experiment, and lower NO3(-) concentrations were observed for acidified relative to non-acidified treatments at IE2. Acidification of both the LF and WS led to higher NH4(+) concentrations as well as an increase of EC for treatment ALFS relative to the control, in the first IE, and lower pH values in the AWSS. Furthermore, the E. coli and total coliform concentrations in AWSS, LFS, and ALFS were significantly higher than in

  7. Aerobic De-Epoxydation of Trichothecene Mycotoxins by a Soil Bacterial Consortium Isolated Using In Situ Soil Enrichment.

    PubMed

    He, Wei-Jie; Yuan, Qing-Song; Zhang, You-Bing; Guo, Mao-Wei; Gong, An-Dong; Zhang, Jing-Bo; Wu, Ai-Bo; Huang, Tao; Qu, Bo; Li, He-Ping; Liao, Yu-Cai

    2016-09-24

    Globally, the trichothecene mycotoxins deoxynivalenol (DON) and nivalenol (NIV) are among the most widely distributed mycotoxins that contaminate small grain cereals. In this study, a bacterial consortium, PGC-3, with de-epoxydation activity was isolated from soil by an in situ soil enrichment method. Screening of 14 soil samples that were sprayed with DON revealed that 4 samples were able to biotransform DON into de-epoxydized DON (dE-DON). Among these, the PGC-3 consortium showed the highest and most stable activity to biotransform DON into dE-DON and NIV into dE-NIV. PGC-3 exhibited de-epoxydation activity at a wide range of pH (5-10) and temperatures (20-37 °C) values under aerobic conditions. Sequential subculturing with a continued exposure to DON substantially reduced the microbial population diversity of this consortium. Analyses of the 16S rDNA sequences indicated that PGC-3 comprised 10 bacterial genera. Among these, one species, Desulfitobacterium, showed a steady increase in relative abundance, from 0.03% to 1.55% (a 52-fold increase), as higher concentrations of DON were used in the subculture media, from 0 to 500 μg/mL. This study establishes the foundation to further develop bioactive agents that can detoxify trichothecene mycotoxins in cereals and enables for the characterization of detoxifying genes and their regulation.

  8. Aerobic De-Epoxydation of Trichothecene Mycotoxins by a Soil Bacterial Consortium Isolated Using In Situ Soil Enrichment

    PubMed Central

    He, Wei-Jie; Yuan, Qing-Song; Zhang, You-Bing; Guo, Mao-Wei; Gong, An-Dong; Zhang, Jing-Bo; Wu, Ai-Bo; Huang, Tao; Qu, Bo; Li, He-Ping; Liao, Yu-Cai

    2016-01-01

    Globally, the trichothecene mycotoxins deoxynivalenol (DON) and nivalenol (NIV) are among the most widely distributed mycotoxins that contaminate small grain cereals. In this study, a bacterial consortium, PGC-3, with de-epoxydation activity was isolated from soil by an in situ soil enrichment method. Screening of 14 soil samples that were sprayed with DON revealed that 4 samples were able to biotransform DON into de-epoxydized DON (dE-DON). Among these, the PGC-3 consortium showed the highest and most stable activity to biotransform DON into dE-DON and NIV into dE-NIV. PGC-3 exhibited de-epoxydation activity at a wide range of pH (5–10) and temperatures (20–37 °C) values under aerobic conditions. Sequential subculturing with a continued exposure to DON substantially reduced the microbial population diversity of this consortium. Analyses of the 16S rDNA sequences indicated that PGC-3 comprised 10 bacterial genera. Among these, one species, Desulfitobacterium, showed a steady increase in relative abundance, from 0.03% to 1.55% (a 52-fold increase), as higher concentrations of DON were used in the subculture media, from 0 to 500 μg/mL. This study establishes the foundation to further develop bioactive agents that can detoxify trichothecene mycotoxins in cereals and enables for the characterization of detoxifying genes and their regulation. PMID:27669304

  9. Aerobic De-Epoxydation of Trichothecene Mycotoxins by a Soil Bacterial Consortium Isolated Using In Situ Soil Enrichment.

    PubMed

    He, Wei-Jie; Yuan, Qing-Song; Zhang, You-Bing; Guo, Mao-Wei; Gong, An-Dong; Zhang, Jing-Bo; Wu, Ai-Bo; Huang, Tao; Qu, Bo; Li, He-Ping; Liao, Yu-Cai

    2016-01-01

    Globally, the trichothecene mycotoxins deoxynivalenol (DON) and nivalenol (NIV) are among the most widely distributed mycotoxins that contaminate small grain cereals. In this study, a bacterial consortium, PGC-3, with de-epoxydation activity was isolated from soil by an in situ soil enrichment method. Screening of 14 soil samples that were sprayed with DON revealed that 4 samples were able to biotransform DON into de-epoxydized DON (dE-DON). Among these, the PGC-3 consortium showed the highest and most stable activity to biotransform DON into dE-DON and NIV into dE-NIV. PGC-3 exhibited de-epoxydation activity at a wide range of pH (5-10) and temperatures (20-37 °C) values under aerobic conditions. Sequential subculturing with a continued exposure to DON substantially reduced the microbial population diversity of this consortium. Analyses of the 16S rDNA sequences indicated that PGC-3 comprised 10 bacterial genera. Among these, one species, Desulfitobacterium, showed a steady increase in relative abundance, from 0.03% to 1.55% (a 52-fold increase), as higher concentrations of DON were used in the subculture media, from 0 to 500 μg/mL. This study establishes the foundation to further develop bioactive agents that can detoxify trichothecene mycotoxins in cereals and enables for the characterization of detoxifying genes and their regulation. PMID:27669304

  10. Influence of a Rhamnolipid Biosurfactant on the Transport of Bacteria through a Sandy Soil

    PubMed Central

    Bai, G.; Brusseau, M. L.; Miller, R. M.

    1997-01-01

    The objective of this study was to investigate the influence of an anionic rhamnolipid biosurfactant on the transport of bacterial cells through soil under saturated conditions. Three cell types with various hydrophobicities, i.e., Pseudomonas aeruginosa ATCC 9027, ATCC 27853, and ATCC 15442, were used in this study. In a series of experiments, columns packed with sterile sand were saturated with sterile artificial groundwater for 15 h, and then 3 pore volumes of (sup3)H-labeled bacterial suspensions with various rhamnolipid concentrations was pumped through the column. This was followed by 4 pore volumes of the rhamnolipid solution alone. The measured bacterial cell breakthrough curves were optimized by using an advection-dispersion transport model incorporating two-domain reversible sorption (instantaneous and rate limited) and with two first-order sink terms for irreversible adsorption. The influence of the rhamnolipid on the surface charge densities of the bacteria and the porous medium was also investigated. The results show that the rhamnolipid enhanced the transport of all cell types tested. For example, the rhamnolipid increased the recovery of the most hydrophilic strain, ATCC 9027, from 22.5 to 56.3%. Similarly, the recovery of ATCC 27853 increased from 36.8 to 49.4%, and the recovery of ATCC 15442, the most hydrophobic strain, increased from 17.7 to 40.5% in the presence of the rhamnolipid. The negative surface charge density of the porous medium was increased, while the surface charge density of the bacteria was not changed in the presence of the rhamnolipid. The model results suggest that the rhamnolipid predominantly affected irreversible adsorption of cells. PMID:16535601

  11. The relevance of in-situ and laboratory characterization of sandy soil hydraulic properties for soil water simulations

    NASA Astrophysics Data System (ADS)

    Rezaei, Meisam; Seuntjens, Piet; Shahidi, Reihaneh; Joris, Ingeborg; Boënne, Wesley; Al-Barri, Bashar; Cornelis, Wim

    2016-03-01

    Field water flow processes can be precisely delineated with proper sets of soil hydraulic properties derived from in situ and/or laboratory experiments. In this study we analyzed and compared soil hydraulic properties obtained by traditional laboratory experiments and inverse optimization tension infiltrometer data along the vertical direction within two typical Podzol profiles with sand texture in a potato field. The main goal was to identify proper sets of hydraulic parameters and to evaluate their relevance on hydrological model performance for irrigation management purposes. Tension disc infiltration experiments were carried out at four and five different depths for both profiles at consecutive negative pressure heads of 12, 6, 3 and 0.1 cm. At the same locations and depths undisturbed samples were taken to determine Mualem-van Genuchten (MVG) hydraulic parameters (θr, residual water content, θs, saturated water content, α and n, shape parameters and Kls, lab saturated hydraulic conductivity) in the laboratory. Results demonstrated horizontal differences and vertical variability of hydraulic properties. The tension disc infiltration data fitted well in inverse modeling using Hydrus 2D/3D in combination with final water content at the end of the experiment, θf. Four MVG parameters (θs, α, n and field saturated hydraulic conductivity Kfs) were estimated (θr set to zero), with estimated Kls and α values being relatively similar to values from Wooding's solution which used as initial value and estimated θs corresponded to (effective) field saturated water content, θf. The laboratory measurement of Kls yielded 2-30 times higher values than the field method Kfs from top to subsoil layers, while there was a significant correlation between both Ks values (r = 0.75). We found significant differences of MVG parameters θs, n and α values between laboratory and field measurements, but again a significant correlation was observed between laboratory and field MVG

  12. Soil Texture and Cultivar Effects on Rice (Oryza sativa, L.) Grain Yield, Yield Components and Water Productivity in Three Water Regimes.

    PubMed

    Dou, Fugen; Soriano, Junel; Tabien, Rodante E; Chen, Kun

    2016-01-01

    The objective of this study was to determine the effects of water regime/soil condition (continuous flooding, saturated, and aerobic), cultivar ('Cocodrie' and 'Rondo'), and soil texture (clay and sandy loam) on rice grain yield, yield components and water productivity using a greenhouse trial. Rice grain yield was significantly affected by soil texture and the interaction between water regime and cultivar. Significantly higher yield was obtained in continuous flooding than in aerobic and saturated soil conditions but the latter treatments were comparable to each other. For Rondo, its grain yield has decreased with soil water regimes in the order of continuous flooding, saturated and aerobic treatments. The rice grain yield in clay soil was 46% higher than in sandy loam soil averaged across cultivar and water regime. Compared to aerobic condition, saturated and continuous flooding treatments had greater panicle numbers. In addition, panicle number in clay soil was 25% higher than in sandy loam soil. The spikelet number of Cocodrie was 29% greater than that of Rondo, indicating that rice cultivar had greater effect on spikelet number than soil type and water management. Water productivity was significantly affected by the interaction of water regime and cultivar. Compared to sandy loam soil, clay soil was 25% higher in water productivity. Our results indicated that cultivar selection and soil texture are important factors in deciding what water management option to practice.

  13. Soil Texture and Cultivar Effects on Rice (Oryza sativa, L.) Grain Yield, Yield Components and Water Productivity in Three Water Regimes

    PubMed Central

    Dou, Fugen; Soriano, Junel; Tabien, Rodante E.; Chen, Kun

    2016-01-01

    The objective of this study was to determine the effects of water regime/soil condition (continuous flooding, saturated, and aerobic), cultivar (‘Cocodrie’ and ‘Rondo’), and soil texture (clay and sandy loam) on rice grain yield, yield components and water productivity using a greenhouse trial. Rice grain yield was significantly affected by soil texture and the interaction between water regime and cultivar. Significantly higher yield was obtained in continuous flooding than in aerobic and saturated soil conditions but the latter treatments were comparable to each other. For Rondo, its grain yield has decreased with soil water regimes in the order of continuous flooding, saturated and aerobic treatments. The rice grain yield in clay soil was 46% higher than in sandy loam soil averaged across cultivar and water regime. Compared to aerobic condition, saturated and continuous flooding treatments had greater panicle numbers. In addition, panicle number in clay soil was 25% higher than in sandy loam soil. The spikelet number of Cocodrie was 29% greater than that of Rondo, indicating that rice cultivar had greater effect on spikelet number than soil type and water management. Water productivity was significantly affected by the interaction of water regime and cultivar. Compared to sandy loam soil, clay soil was 25% higher in water productivity. Our results indicated that cultivar selection and soil texture are important factors in deciding what water management option to practice. PMID:26978525

  14. Soil Texture and Cultivar Effects on Rice (Oryza sativa, L.) Grain Yield, Yield Components and Water Productivity in Three Water Regimes.

    PubMed

    Dou, Fugen; Soriano, Junel; Tabien, Rodante E; Chen, Kun

    2016-01-01

    The objective of this study was to determine the effects of water regime/soil condition (continuous flooding, saturated, and aerobic), cultivar ('Cocodrie' and 'Rondo'), and soil texture (clay and sandy loam) on rice grain yield, yield components and water productivity using a greenhouse trial. Rice grain yield was significantly affected by soil texture and the interaction between water regime and cultivar. Significantly higher yield was obtained in continuous flooding than in aerobic and saturated soil conditions but the latter treatments were comparable to each other. For Rondo, its grain yield has decreased with soil water regimes in the order of continuous flooding, saturated and aerobic treatments. The rice grain yield in clay soil was 46% higher than in sandy loam soil averaged across cultivar and water regime. Compared to aerobic condition, saturated and continuous flooding treatments had greater panicle numbers. In addition, panicle number in clay soil was 25% higher than in sandy loam soil. The spikelet number of Cocodrie was 29% greater than that of Rondo, indicating that rice cultivar had greater effect on spikelet number than soil type and water management. Water productivity was significantly affected by the interaction of water regime and cultivar. Compared to sandy loam soil, clay soil was 25% higher in water productivity. Our results indicated that cultivar selection and soil texture are important factors in deciding what water management option to practice. PMID:26978525

  15. Mitigation of Water Stress on Apple Trees under Rotational Irrigation Conditions by Increasing the Application Rate of Organic Fertilizers to Sandy Soils

    NASA Astrophysics Data System (ADS)

    Hamed, Lamy Mamdoh Mohamed; Ramadan Eid, Abdelraouf; Mohsmed Rabie Abdellatif Abdelaziz, Adel; Fathy Abdelsalam Essa, El-Sayed

    2016-04-01

    Egypt, as part of Mediterranean regions, is characterized by irregular and low rainfall amount which varies between (30-150 mm.year-1), and characterized also by high temperature which increase the rate of evapotranspiration from the cultivated soil. On the other hand, New reclaimed soils are mostly occupies around 84 % of total area of Egypt, which is mainly sandy soils. These soils generally characterized by low water capacity holding, soil organic matter, and weak in nutrients retention. Under these conditions which have a great influence on crop production, there is a great needing to increase the crop water use efficiency and increasing of nutrient retention in sandy soils. In this context, two field experiments were carried out on sand soil located in north Cairo-Egypt at the experimental farm of National Research Center, El-NUBARIA, (latitude 30° 30' N, and longitude 30° 19' E). The effect of compost rates on soil hydraulic characteristics, fruit yields, quality traits, and water use efficiency and productivity of apple tree (Apple Anna Cultivar), was studied under deficit irrigation conditions. Four rates of compost [I1: control, I2: 12 ton.ha-1., I3: 24 ton.ha-1., I4: 36 ton.ha-1. and I5:48 ton.ha-1.] were applied under irrigation frequencies of (IF1 :once per week; IF2 :twice per week, IF3 :three times per week). The obtained results indicated that by increasing the application rate of compost, the available water capacity and saturated water content of sandy soil have been enhanced. In the same time, the fruit yield, quality traits and water productivity were increased by increasing the application rate of compost. It is worthy to mention that the I5IF3 treatment gave the highest values of fruit yield, quality traits and water productivity, whereas I1IF1 treatment gave the lowest values of all the above mentioned variables. As result, for apple cultivation in El-NUBARIA region, the recommended rate of compost is 48 ton.ha-1 and irrigation frequency

  16. Dolomite phosphate rock (DPR) application in acidic sandy soil in reducing leaching of phosphorus and heavy metals-a column leaching study.

    PubMed

    Yang, Yuangen; He, Zhenli; Yang, Xiaoe; Stoffella, Peter J

    2013-06-01

    A column leaching study was designed to investigate the leaching potential of phosphorus (P) and heavy metals from acidic sandy soils applied with dolomite phosphate rock (DPR) fertilizers containing varying amounts of DPR material and N-Viro soils. DPR fertilizers were made from DPR materials mixing with N-Viro soils at the ratios of 30, 40, 50, 60, and 70 %, and applied in acidic sandy soils at the level of 100 mg available P per kilogram soil. A control and a soluble P chemical fertilizer were also included. The amended soils were incubated at room temperature with 70 % field water holding capacity for 21 days before packed into a soil column and subjected to leaching. Seven leaching events were conducted at days 1, 3, 7, 14, 28, 56, and 70, respectively, and 258.9 mL of deionized water was applied at each leaching events. The leachate was collected for the analyses of pH, electrical conductivity (EC), dissolved organic carbon (DOC), major elements, and heavy metals. DPR fertilizer application resulted in elevations up to 1 unit in pH, 7-10 times in EC, and 20-40 times in K and Ca concentrations, but 3-10 times reduction in P concentration in the leachate as compared with the chemical fertilizer or the control. After seven leaching events, DPR fertilizers with adequate DPR materials significantly reduced cumulative leaching losses of Fe, P, Mn, Cu, and Zn by 20, 55, 3.7, 2.7, and 2.5 times than chemical fertilizer or control. Even though higher cumulative losses of Pb, Co, and Ni were observed after DPR fertilizer application, the loss of Pb, Co, and Ni in leachate was <0.10 mg (in total 1,812 mL leachate). Significant correlations of pH (negative) and DOC (positive) with Cu, Pb, and Zn (P<0.01) in leachate were observed. The results indicated that DPR fertilizers had a great advantage over the soluble chemical fertilizer in reducing P loss from the acidic sandy soil with minimal likelihood of heavy metal risk to the water environment. pH elevation and high

  17. Mitigation of Water Stress on Apple Trees under Rotational Irrigation Conditions by Increasing the Application Rate of Organic Fertilizers to Sandy Soils

    NASA Astrophysics Data System (ADS)

    Hamed, Lamy Mamdoh Mohamed; Ramadan Eid, Abdelraouf; Mohsmed Rabie Abdellatif Abdelaziz, Adel; Fathy Abdelsalam Essa, El-Sayed

    2016-04-01

    Egypt, as part of Mediterranean regions, is characterized by irregular and low rainfall amount which varies between (30-150 mm.year‑1), and characterized also by high temperature which increase the rate of evapotranspiration from the cultivated soil. On the other hand, New reclaimed soils are mostly occupies around 84 % of total area of Egypt, which is mainly sandy soils. These soils generally characterized by low water capacity holding, soil organic matter, and weak in nutrients retention. Under these conditions which have a great influence on crop production, there is a great needing to increase the crop water use efficiency and increasing of nutrient retention in sandy soils. In this context, two field experiments were carried out on sand soil located in north Cairo-Egypt at the experimental farm of National Research Center, El-NUBARIA, (latitude 30° 30' N, and longitude 30° 19' E). The effect of compost rates on soil hydraulic characteristics, fruit yields, quality traits, and water use efficiency and productivity of apple tree (Apple Anna Cultivar), was studied under deficit irrigation conditions. Four rates of compost [I1: control, I2: 12 ton.ha‑1., I3: 24 ton.ha‑1., I4: 36 ton.ha‑1. and I5:48 ton.ha‑1.] were applied under irrigation frequencies of (IF1 :once per week; IF2 :twice per week, IF3 :three times per week). The obtained results indicated that by increasing the application rate of compost, the available water capacity and saturated water content of sandy soil have been enhanced. In the same time, the fruit yield, quality traits and water productivity were increased by increasing the application rate of compost. It is worthy to mention that the I5IF3 treatment gave the highest values of fruit yield, quality traits and water productivity, whereas I1IF1 treatment gave the lowest values of all the above mentioned variables. As result, for apple cultivation in El-NUBARIA region, the recommended rate of compost is 48 ton.ha‑1 and irrigation

  18. [Effects of understory removal and nitrogen addition on the soil chemical and biological properties of Pinus sylvestris var. mongolica plantation in Keerqin Sandy Land].

    PubMed

    Lin, Gui-Gang; Zhao, Qiong; Zhao, Lei; Li, Hui-Chao; Zeng, De-Hui

    2012-05-01

    A full factorial experiment was conducted to study the effects of understory removal and nitrogen addition (8 g x m(-2)) on the soil NO(3-)-N and NH(4+)-N concentrations, potential net nitrogen mineralization rate (PNM) and nitrification rate (PNN), microbial biomass C (MBC) and N (MBN), MBC/MBN, urease and acid phosphomonoesterase activities, and Olsen-P concentration in a Pinus sylvestris var. mongolica plantation in Keerqin Sandy Land during a growth season. Understory removal decreased the soil NH(4+)-N concentration, PNM, MBC, and MBN/MBN significantly, increased the soil Olsen-P concentration, but had little effects on the soil NO(3-)-N concentration, PNN, and urease and acid phosphomonoesterase activities. Nitrogen addition increased the soil NO(3-)-N concentration, PNM and PNN significantly, but had little effects on the other test properties. The interaction between understory removal and nitrogen addition had significant effects on the soil NH(4+)-N concentration, but little effects on the soil NO(3-)-N concentration. However, the soil NO(3-)-N concentration in the plots of understory removal with nitrogen addition was increased by 27%, compared with the plots of nitrogen addition alone, which might lead to the leaching of NO3-. It was suggested that understory vegetation could play an important role in affecting the soil chemical and biological properties in Mongolian pine plantations, and hence, the importance of understory vegetation should not be neglected when the forest management and restoration were implemented. PMID:22919826

  19. Diversity of aerobic methanotrophic bacteria in a permafrost active layer soil of the Lena Delta, Siberia.

    PubMed

    Liebner, Susanne; Rublack, Katja; Stuehrmann, Torben; Wagner, Dirk

    2009-01-01

    With this study, we present first data on the diversity of aerobic methanotrophic bacteria (MOB) in an Arctic permafrost active layer soil of the Lena Delta, Siberia. Applying denaturing gradient gel electrophoresis and cloning of 16S ribosomal ribonucleic acid (rRNA) and pmoA gene fragments of active layer samples, we found a general restriction of the methanotrophic diversity to sequences closely related to the genera Methylobacter and Methylosarcina, both type I MOB. In contrast, we revealed a distinct species-level diversity. Based on phylogenetic analysis of the 16S rRNA gene, two new clusters of MOB specific for the permafrost active layer soil of this study were found. In total, 8 out of 13 operational taxonomic units detected belong to these clusters. Members of these clusters were closely related to Methylobacter psychrophilus and Methylobacter tundripaludum, both isolated from Arctic environments. A dominance of MOB closely related to M. psychrophilus and M. tundripaludum was confirmed by an additional pmoA gene analysis. We used diversity indices such as the Shannon diversity index or the Chao1 richness estimator in order to compare the MOB community near the surface and near the permafrost table. We determined a similar diversity of the MOB community in both depths and suggest that it is not influenced by the extreme physical and geochemical gradients in the active layer. PMID:18592300

  20. Drivers of spatial patterns of physiological and soil parameters at micro- and field scale in a Hungarian sandy grassland

    NASA Astrophysics Data System (ADS)

    Fóti, Szilvia; Balogh, János; Papp, Marianna; Zimmermann, Zita; Szabó, Gábor; Herbst, Michael; Biró, Marianna; Bartha, Sándor; Horváth, László; Nagy, Zoltán

    2014-05-01

    Plant physiological and soil parameters were sampled at two spatial scales on mowed and grazed sites of a semiarid sandy grassland in Hungary. Samples from 80×60 m grids of 10 m resolution with additional random points represented the field scale (78 positions), while measurements along every 20 cm of circular transects of 15 m length represented the micro-scale (75 positions). 22 transects were measured between 2004 and 2012 at micro-scale, and 6 grids in 2012-2013 at field scale. At the micro-scale, there was no apparent elevation (E) difference, nor any other spatial non-stationarity. Contrarily, apparent micro-relief and above-ground biomass (AGB) differences emerged at the field scale. Sampled variables were soil water content (SWC), soil temperature (Ts) and soil CO2 efflux (Rs) at the micro-scale, and these were complemented with E and AGB at the field scale. N2O was sampled spatially once at both sites, in autumn 2012. Spatial patterns of the variables were investigated by variograms and cross-variograms. Autocorrelation lengths of the measured variables varied between 0-3.5 m at the micro scale. SWC was the main determinant of both the spatial variability and patch size of Rs, because dry conditions increased variability of the measured flux together with the characteristic patch size of Rs. Furthermore, optimal sample size and adequate sampling scheme could be estimated on the basis of actual SWC. Ts proved to negatively co-vary with SWC, which resulted in negative spatial dependency between Ts and Rs, contrary to the expectations. Effect of SWC was of two different sorts in this respect, in dry patches it directly limited Rs, while in wet patches it had a cooling effect, leading to the confounding response of Rs to Ts. These observations pointed to the relevance of SWC in model approaches. At field scale, deviations in E and AGB produced a different setting for spatial correlation. In case of the mowed site, we found a coherent patch structure of about

  1. Degradation of vinyl acetate by soil, sewage, sludge, and the newly isolated aerobic bacterium V2.

    PubMed Central

    Nieder, M; Sunarko, B; Meyer, O

    1990-01-01

    Vinyl acetate is subject to microbial degradation in the environment and by pure cultures. It was hydrolyzed by samples of soil, sludge, and sewage at rates of up to 6.38 and 1 mmol/h per g (dry weight) under aerobic and anaerobic conditions, respectively. Four yeasts and thirteen bacteria that feed aerobically on vinyl acetate were isolated. The pathway of vinyl acetate degradation was studied in bacterium V2. Vinyl acetate was degraded to acetate as follows: vinyl acetate + NAD(P)+----2 acetate + NAD(P)H + H+. The acetate was then converted to acetyl coenzyme A and oxidized through the tricarboxylic acid cycle and the glyoxylate bypass. The key enzyme of the pathway is vinyl acetate esterase, which hydrolyzed the ester to acetate and vinyl alcohol. The latter isomerized spontaneously to acetaldehyde and was then converted to acetate. The acetaldehyde was disproportionated into ethanol and acetate. The enzymes involved in the metabolism of vinyl acetate were studied in extracts. Vinyl acetate esterase (Km = 6.13 mM) was also active with indoxyl acetate (Km = 0.98 mM), providing the basis for a convenient spectrophotometric test. Substrates of aldehyde dehydrogenase were formaldehyde, acetaldehyde, propionaldehyde, and butyraldehyde. The enzyme was equally active with NAD+ or NADP+. Alcohol dehydrogenase was active with ethanol (Km = 0.24 mM), 1-propanol (Km = 0.34 mM), and 1-butanol (Km = 0.16 mM) and was linked to NAD+. The molecular sizes of aldehyde dehydrogenase and alcohol dehydrogenase were 145 and 215 kilodaltons, respectively. PMID:2285314

  2. Using a tank flow model with PEARL to measure the variation in pesticide persistence between anaerobic and aerobic soil conditions

    NASA Astrophysics Data System (ADS)

    Real, Joaquin; Seiterle-Winn, Natalie; Frances, Felix

    2013-04-01

    Pesticide leaching is very sensitive to the transformation rate (Boesten and Linden, 1991). The values of the transformation rates of the pesticides differ between aerobic and anaerobic soil conditions. The main objective is to determine if there is a significant variation in pesticide persistence between aerobic and anaerobic soil conditions. An auxiliary hydrological model is used with the PEARL model (Leistra et al, 2001). The auxiliary model determines the degree of saturation of the soil at each time step. The value of the degradation rate for a given pesticide in the PEARL model varies depending on the time periods with saturated or unsaturated soil conditions. The proposed auxiliary model has been conceptualized as a static tank flow model based on the actual evapotranspiration of the crop plants. It is based on the RIBAV model (Garcia-Arias et al. 2012) used for the modeling of riparian vegetation zonation. The tank represents a soil column which also includes the superficial root layer. The lower capacity limit of this tank is the permanent wilting moisture of the soil. The upper capacity limit represents the saturated condition of the soil. The tanks input flows are precipitation and irrigation. In contrast, output flows are the actual evapotranspiration and the discharge of the tank. The most relevant model parameters are the soil retention curves, the crop parameters (specially related to root depths and crop coefficients) and the daily meteorological data (such as precipitation and potential evapotranspiration). The main output of the auxiliary model is the relative soil moisture, which determines if the PEARL model should use the transformation rate value for aerobic or for anaerobic conditions. In order to prove the applicability of the model, it was tested with various pesticides, which cover a wide range of transformation rates. The results show that the auxiliary tank model is able to determine the partition of the pesticides degrading in both

  3. Microbial transformation of 8:2 fluorotelomer acrylate and methacrylate in aerobic soils.

    PubMed

    Royer, Laurel A; Lee, Linda S; Russell, Mark H; Nies, Loring F; Turco, Ronald F

    2015-06-01

    Biotransformation of fluorotelomer (FT) compounds, such as 8:2 FT alcohol (FTOH) is now recognized to be a source of perfluorooctanoic acid (PFOA) as well as other perfluoroalkyl acids. In this study, microbially mediated hydrolysis of FT industrial intermediates 8:2 FT acrylate (8:2 FTAC) and 8:2 FT methacrylate (8:2 FTMAC) was evaluated in aerobic soils for up to 105d. At designated times, triplicate microcosms were sacrificed by sampling the headspace for volatile FTOHs followed by sequential extraction of soil for the parent monomers as well as transient and terminal degradation products. Both FTAC and FTMAC were hydrolyzed at the ester linkage as evidenced by 8:2 FTOH production. 8:2 FTAC and FTMAC degraded rapidly with half-lives ⩽5d and 15d, respectively. Maximum 8:2 FTOH levels were 6-13mol% within 3-6d. Consistent with the known biotransformation pathway of 8:2 FTOH, FT carboxylic acids and perfluoroalkyl carboxylic acids were subsequently generated including up to 10.3mol% of PFOA (105d). A total mass balance (parent plus metabolites) of 50-75mol% was observed on the last sampling day. 7:2 sFTOH, a direct precursor to PFOA, unexpectedly increased throughout the incubation period. The likely, but unconfirmed, concomitant production of acrylic acids was proposed as altering expected degradation patterns. Biotransformation of 8:2 FTAC, 8:2 FTMAC, and previously reported 8:2 FT-stearate for the same soils revealed the effect of the non-fluorinated terminus group linked to the FT chain on the electronic differences that affect microbially-mediated ester cleavage rates.

  4. Microbial transformation of 8:2 fluorotelomer acrylate and methacrylate in aerobic soils.

    PubMed

    Royer, Laurel A; Lee, Linda S; Russell, Mark H; Nies, Loring F; Turco, Ronald F

    2015-06-01

    Biotransformation of fluorotelomer (FT) compounds, such as 8:2 FT alcohol (FTOH) is now recognized to be a source of perfluorooctanoic acid (PFOA) as well as other perfluoroalkyl acids. In this study, microbially mediated hydrolysis of FT industrial intermediates 8:2 FT acrylate (8:2 FTAC) and 8:2 FT methacrylate (8:2 FTMAC) was evaluated in aerobic soils for up to 105d. At designated times, triplicate microcosms were sacrificed by sampling the headspace for volatile FTOHs followed by sequential extraction of soil for the parent monomers as well as transient and terminal degradation products. Both FTAC and FTMAC were hydrolyzed at the ester linkage as evidenced by 8:2 FTOH production. 8:2 FTAC and FTMAC degraded rapidly with half-lives ⩽5d and 15d, respectively. Maximum 8:2 FTOH levels were 6-13mol% within 3-6d. Consistent with the known biotransformation pathway of 8:2 FTOH, FT carboxylic acids and perfluoroalkyl carboxylic acids were subsequently generated including up to 10.3mol% of PFOA (105d). A total mass balance (parent plus metabolites) of 50-75mol% was observed on the last sampling day. 7:2 sFTOH, a direct precursor to PFOA, unexpectedly increased throughout the incubation period. The likely, but unconfirmed, concomitant production of acrylic acids was proposed as altering expected degradation patterns. Biotransformation of 8:2 FTAC, 8:2 FTMAC, and previously reported 8:2 FT-stearate for the same soils revealed the effect of the non-fluorinated terminus group linked to the FT chain on the electronic differences that affect microbially-mediated ester cleavage rates. PMID:25449186

  5. Cadmium adsorption on plant- and manure-derived biochar and biochar-amended sandy soils: impact of bulk and surface properties.

    PubMed

    Xu, Dongyu; Zhao, Ye; Sun, Ke; Gao, Bo; Wang, Ziying; Jin, Jie; Zhang, Zheyun; Wang, Shuifeng; Yan, Yu; Liu, Xitao; Wu, Fengchang

    2014-09-01

    To investigate the role of the bulk and surface composition of both biochar and biochar-amended soils in the adsorption of Cd(2+), as well as the influence of different biochars added to the soils on Cd(2+) adsorption, swine-manure-derived biochars (BSs) and wheat-straw-derived biochars (BWs) were produced at 300, 450, and 600°C. These biochars were added to a sandy soil to investigate the effect of biochars on the adsorption of Cd(2+) by soil. The significantly higher surface C content of the amended soils compared to their bulk C content suggests that the minerals of the biochar-amended soils are most likely covered primarily by biochars. The maximum adsorption capacity (Qmax,total) of the BSs was 10-15 times higher than that of the BWs due to the high polarity and ash content of the BSs. The polarity ((N+O)/C) of the low-temperature biochars greatly affected their Cd(2+) adsorption. The Qmax,total of the BS-amended soils increased with increasing dose, whereas the Qmax,total of the BW-amended soils showed the opposite behavior, which was attributed to the different surface composition characteristics of the two types of soil. The BSs were more effective in immobilizing Cd(2+) upon application to the soil relative to the BWs. This study elucidates the spatial distribution of biochars in biochar-amended soils and highlights the importance of the surface composition of the investigated samples in Cd(2+) adsorption.

  6. On-farm treatment of dairy soiled water using aerobic woodchip filters.

    PubMed

    Ruane, Eimear M; Murphy, Paul N C; Healy, Mark G; French, Padraig; Rodgers, Michael

    2011-12-15

    Dairy soiled water (DSW) is produced on dairy farms through the washing-down of milking parlours and holding areas, and is generally applied to land. However, there is a risk of nutrient loss to surface and ground waters from land application. The aim of this study was to use aerobic woodchip filters to remove organic matter, suspended solids (SS) and nutrients from DSW. This novel treatment method would allow the re-use of the final effluent from the woodchip filters to wash down yards, thereby reducing water usage and environmental risks associated with land spreading. Three replicate 100 m(2) farm-scale woodchip filters, each 1 m deep, were constructed and operated to treat DSW from 300 cows over an 11-month study duration. The filters were loaded at a hydraulic loading rate of 30 L m(-2) d(-1), applied in four doses through a network of pipes on the filter surface. Average influent concentrations of chemical oxygen demand (COD), SS and total nitrogen (TN) of 5750 ± 1441 mg L(-1), 602 ± 303 mg L(-1) and 357 ± 100 mg L(-1), respectively, were reduced by 66, 86 and 57% in the filters. Effluent nutrient concentrations remained relatively stable over the study period, indicating the effectiveness of the filter despite increasing and/or fluctuating influent concentrations. Woodchip filters are a low cost, minimal maintenance treatment system, using a renewable resource that can be easily integrated into existing farm infrastructure.

  7. Sorption/desorption of 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane(4,4'-DDT) on a sandy loam soil.

    PubMed

    Erdem, Ziya; Cutright, Teresa J

    2015-02-01

    1,1,1-Trichloro-2,2-bis(p-chlorophenyl)ethane(4,4'-DDT) is a pesticide well-known for its negative health and environmental effects. Despite being banned by a majority of world countries more than 30 years ago, its persistence in the environment is a continuing problem even today. The objective of the study was the investigation of sorption/desorption behavior of 4,4'-DDT in sandy loam soil. The impact of contaminant concentration and age was observed with three different experiments. The sorption percentages at the end of the short time step (8 h) were 50 and 92 %, for initial concentrations 2.26 and 5.28 mg/L, respectively. When freshly spiked soil was subjected to a conventional sorption study, 82 to 99.6 % of the initial aqueous DDT concentrations were sorbed within 24 h. When modeled with a Freundlich isotherm, the log K f was found to be 3.62. After six consecutive 24 h desorption steps, 33 to 96.6 % still remained in the soil. This was more pronounced for soils that had been aged for 60 days. After seven consecutive 24 h desorption steps of aged soil, the percent remaining sorbed to the soil were 44, 64, and 77 %, for 25, 250, and 500 mg/kg, respectively. All results show that 4,4-DDT has a tendency of sorbing to the soil rapidly and showing resistance to desorption. When comparing desorption values, aged soils were seen to desorb less than non-aged soils. This result was attributed to stronger binding to soil with increased contact time.

  8. Aerobic biogenesis of selenium nanospheres by Bacillus cereus isolated from coalmine soil

    PubMed Central

    2010-01-01

    Background Microorganisms that are exposed to pollutants in the environment, such as metals/metalloids, have a remarkable ability to fight the metal stress by various mechanisms. These metal-microbe interactions have already found an important role in biotechnological applications. It is only recently that microorganisms have been explored as potential biofactories for synthesis of metal/metalloid nanoparticles. Biosynthesis of selenium (Se0) nanospheres in aerobic conditions by a bacterial strain isolated from the coalmine soil is reported in the present study. Results The strain CM100B, identified as Bacillus cereus by morphological, biochemical and 16S rRNA gene sequencing [GenBank:GU551935.1] was studied for its ability to generate selenium nanoparticles (SNs) by transformation of toxic selenite (SeO32-) anions into red elemental selenium (Se0) under aerobic conditions. Also, the ability of the strain to tolerate high levels of toxic selenite ions was studied by challenging the microbe with different concentrations of sodium selenite (0.5 mM-10 mM). ESEM, AFM and SEM studies revealed the spherical Se0 nanospheres adhering to bacterial biomass as well as present as free particles. The TEM microscopy showed the accumulation of spherical nanostructures as intracellular and extracellular deposits. The deposits were identified as element selenium by EDX analysis. This is also indicated by the red coloration of the culture broth that starts within 2-3 h of exposure to selenite oxyions. Selenium nanoparticles (SNs) were further characterized by UV-Visible spectroscopy, TEM and zeta potential measurement. The size of nanospheres was in the range of 150-200 nm with high negative charge of -46.86 mV. Conclusions This bacterial isolate has the potential to be used as a bionanofactory for the synthesis of stable, nearly monodisperse Se0 nanoparticles as well as for detoxification of the toxic selenite anions in the environment. A hypothetical mechanism for the biogenesis

  9. Influence of humidity and of the electric and magnetic microwave radiation fields on the remediation of TCE-contaminated natural sandy soils.

    PubMed

    Horikoshi, Satoshi; Muratani, Masaru; Miyabe, Kouta; Ohmura, Keisuke; Hirowatari, Tomoaki; Serpone, Nick; Abe, Masahiko

    2011-01-01

    The influence of moisture content (15% w/w) on the remediation (vaporization) of trichloroethylene (TCE) present in natural sands, chosen as a TCE-polluted model system for soils, was investigated with regard to applied microwave power levels, the depth of the sand sample, and the dielectric factors. The heating process occurring in the sand samples arises through the microwave conduction loss heating and dielectric loss heating mechanisms. The characteristic relevance of the electric and magnetic microwave radiation fields to the heating mechanisms was also examined. Heating by the magnetic microwave radiation field was considerable when magnetite was added to the dry and wet sand samples as the microwave absorber. Optimal microwave conditions are reported for a single-mode microwave applicator. Near-quantitative elimination of the TCE contaminant was achieved for sandy soils within a very short time.

  10. Influence of humidity and of the electric and magnetic microwave radiation fields on the remediation of TCE-contaminated natural sandy soils.

    PubMed

    Horikoshi, Satoshi; Muratani, Masaru; Miyabe, Kouta; Ohmura, Keisuke; Hirowatari, Tomoaki; Serpone, Nick; Abe, Masahiko

    2011-01-01

    The influence of moisture content (15% w/w) on the remediation (vaporization) of trichloroethylene (TCE) present in natural sands, chosen as a TCE-polluted model system for soils, was investigated with regard to applied microwave power levels, the depth of the sand sample, and the dielectric factors. The heating process occurring in the sand samples arises through the microwave conduction loss heating and dielectric loss heating mechanisms. The characteristic relevance of the electric and magnetic microwave radiation fields to the heating mechanisms was also examined. Heating by the magnetic microwave radiation field was considerable when magnetite was added to the dry and wet sand samples as the microwave absorber. Optimal microwave conditions are reported for a single-mode microwave applicator. Near-quantitative elimination of the TCE contaminant was achieved for sandy soils within a very short time. PMID:21701102

  11. Aerobic Degradation of N-Methyl-4-Nitroaniline (MNA) by Pseudomonas sp. Strain FK357 Isolated from Soil

    PubMed Central

    Khan, Fazlurrahman; Vyas, Bhawna; Pal, Deepika; Cameotra, Swaranjit Singh

    2013-01-01

    N-Methyl-4-nitroaniline (MNA) is used as an additive to lower the melting temperature of energetic materials in the synthesis of insensitive explosives. Although the biotransformation of MNA under anaerobic condition has been reported, its aerobic microbial degradation has not been documented yet. A soil microcosms study showed the efficient aerobic degradation of MNA by the inhabitant soil microorganisms. An aerobic bacterium, Pseudomonas sp. strain FK357, able to utilize MNA as the sole carbon, nitrogen, and energy source, was isolated from soil microcosms. HPLC and GC-MS analysis of the samples obtained from growth and resting cell studies showed the formation of 4-nitroaniline (4-NA), 4-aminophenol (4-AP), and 1, 2, 4-benzenetriol (BT) as major metabolic intermediates in the MNA degradation pathway. Enzymatic assay carried out on cell-free lysates of MNA grown cells confirmed N-demethylation reaction is the first step of MNA degradation with the formation of 4-NA and formaldehyde products. Flavin-dependent transformation of 4-NA to 4-AP in cell extracts demonstrated that the second step of MNA degradation is a monooxygenation. Furthermore, conversion of 4-AP to BT by MNA grown cells indicates the involvement of oxidative deamination (release of NH2 substituent) reaction in third step of MNA degradation. Subsequent degradation of BT occurs by the action of benzenetriol 1, 2-dioxygenase as reported for the degradation of 4-nitrophenol. This is the first report on aerobic degradation of MNA by a single bacterium along with elucidation of metabolic pathway. PMID:24116023

  12. Complete remediation of PCE contaminated unsaturated soils by sequential anaerobic-aerobic bioventing.

    PubMed

    Mihopoulos, P G; Suidan, M T; Sayles, G D

    2001-01-01

    Bioventing principles have been applied to completely dechlorinate tetrachloroethylene vapors in the unsaturated zone in a sequential anaerobic-aerobic pattern. The aerobic step yields trans-DCE and VC as PCE reductive dechlorination byproducts, while TCE and cis-DCE are observed as intermediates. The aerobic step results in rapid oxidation of the VC and trans-DCE to carbon dioxide. Hydrogen was delivered in the gas phase as a reducing agent for the anaerobic step at levels of 1%, and oxygen at 4.2% was used as an electron acceptor in the aerobic step. PCE and VC half lives in the anaerobic and aerobic steps respectively, where less than 10 min.

  13. Spatial pattern and heterogeneity of soil organic carbon and nitrogen in sand dunes related to vegetation change and geomorphic position in Horqin Sandy Land, Northern China.

    PubMed

    Zuo, X A; Zhao, X Y; Zhao, H L; Guo, Y R; Zhang, T H; Cui, J Y

    2010-05-01

    To assesses the effect of geomorphology, topography, and vegetation changes on spatial pattern of soil organic carbon (C) and total nitrogen (N) in sand dunes, we used the quantitative methods to examine the spatial heterogeneity of vegetation cover, soil organic C, and total N in an 11-year naturally restored mobile dune (RMD11) and a 20-year naturally restored mobile dune (RMD20) that had been fenced to exclude grazing in Horqin Sandy Land, northern China. Our results showed that the vegetation cover, plant density, species number and diversity, soil organic C, and total N increased from RMD11 to RMD20 and increased from the 50 x 50-m plot (crest) to the 100 x 100-m plot (slope) in each dune. Geostatistical analysis showed that the spatial structural variance accounted for the largest proportion of the total sample variance in vegetation cover, soil organic C, and total N in each dune plot. Calculated spatial autocorrelation ranges of vegetation cover, soil organic C, and total N increased from RMD11 to RMD20, indicating that longer time since vegetation restoration results in a more homogeneous distribution of vegetation cover, soil organic C, and total N in sand dunes. In addition, the spatial continuity of vegetation cover, soil organic C, and total N decreased from the 50 x 50-m plot (crest) to the 100 x 100-m plot (slope) in each dune. These results suggest that the spatial distribution of soil organic C and total N in sand dunes is associated closely with geomorphic position related to the dune crest and slope, relative elevation of sampling site, and vegetation cover. Understanding the principles of this relationship between them may guide strategies for the conservation and management of semiarid dune ecosystems.

  14. [Effects of different vegetation restoration patterns on the diversity of soil nitrogen-fixing microbes in Hulunbeier sandy land, Inner Mongolia of North China].

    PubMed

    Li, Gang; Wang, Li-Juan; Li, Yu-Jie; Qiao, Jiang; Zhang, Hai-Fang; Song, Xiao-Long; Yang, Dian-Lin

    2013-06-01

    By using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and sequence analysis, this paper studied the nifH gene diversity and community structure of soil nitrogen-fixing microbes in Hulunbeier sandy land of Inner Mongolia under four years management of five vegetation restoration modes, i. e., mixed-planting of Agropyron cristatum, Hedysarum fruticosum, Caragana korshinskii, and Elymus nutans (ACHE) and of Agropyron cristatum and Hedysarum fruticosum (AC), and mono-planting of Caragana korshinskii (UC), Agropyron cristatum (UA), and Hedysarum fruticosum (UH), taking the bare land as the control (CK). There existed significant differences in the community composition of nitrogen-fixing microbes among the five vegetation restoration patterns. The Shannon index of the nifH gene was the highest under ACHE, followed by under AC, UC, UA, and UH, and the lowest in CK. Except that UH and CK had less difference in the Shannon index, the other four vegetation restoration modes had a significantly higher Shannon index than CK (P < 0.05). The phylogenetic analysis showed that the soil nitrogen-fixing microbes under UA, UH, and UC were mainly of cyanobacteria, but the soil nitrogen-fixing microbes under AC and ACHE changed obviously, mainly of proteobacteria, and also of cyanobacteria. The canonical correlation analysis showed that the soil total phosphorus, available phosphorus, total nitrogen, and nitrate nitrogen contents under the five vegetation restoration modes had significant effects on the nitrogen-fixing microbial communities, and there existed significant correlations among the soil total phosphorus, available phosphorus, total nitrogen, and nitrate nitrogen. It was suggested that the variations of the community composition of soil nitrogen-fixing microbes under the five vegetation restoration modes were resulted from the interactive and combined effects of the soil physical and chemical factors.

  15. [Effects of different vegetation restoration patterns on the diversity of soil nitrogen-fixing microbes in Hulunbeier sandy land, Inner Mongolia of North China].

    PubMed

    Li, Gang; Wang, Li-Juan; Li, Yu-Jie; Qiao, Jiang; Zhang, Hai-Fang; Song, Xiao-Long; Yang, Dian-Lin

    2013-06-01

    By using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and sequence analysis, this paper studied the nifH gene diversity and community structure of soil nitrogen-fixing microbes in Hulunbeier sandy land of Inner Mongolia under four years management of five vegetation restoration modes, i. e., mixed-planting of Agropyron cristatum, Hedysarum fruticosum, Caragana korshinskii, and Elymus nutans (ACHE) and of Agropyron cristatum and Hedysarum fruticosum (AC), and mono-planting of Caragana korshinskii (UC), Agropyron cristatum (UA), and Hedysarum fruticosum (UH), taking the bare land as the control (CK). There existed significant differences in the community composition of nitrogen-fixing microbes among the five vegetation restoration patterns. The Shannon index of the nifH gene was the highest under ACHE, followed by under AC, UC, UA, and UH, and the lowest in CK. Except that UH and CK had less difference in the Shannon index, the other four vegetation restoration modes had a significantly higher Shannon index than CK (P < 0.05). The phylogenetic analysis showed that the soil nitrogen-fixing microbes under UA, UH, and UC were mainly of cyanobacteria, but the soil nitrogen-fixing microbes under AC and ACHE changed obviously, mainly of proteobacteria, and also of cyanobacteria. The canonical correlation analysis showed that the soil total phosphorus, available phosphorus, total nitrogen, and nitrate nitrogen contents under the five vegetation restoration modes had significant effects on the nitrogen-fixing microbial communities, and there existed significant correlations among the soil total phosphorus, available phosphorus, total nitrogen, and nitrate nitrogen. It was suggested that the variations of the community composition of soil nitrogen-fixing microbes under the five vegetation restoration modes were resulted from the interactive and combined effects of the soil physical and chemical factors. PMID:24066552

  16. Comparative studies on heavy metal uptake by plants from anaerobically and aerobically digested sludge-amended soil

    SciTech Connect

    Joseph, K.T.

    1983-01-01

    A study was undertaken to compare and contrast the effects of cropland application of varying quantities of anaerobically and aerobically digested sludge from a municipal wastewater treatment plant, on the uptake of certain heavy metals such as Zn, Cd, Cu, Ni, and Pb by six different types of plants (bean, tomato, carrot, cucumber, cantaloupe and sweet corn) grown on the sludge-applied soil and the accumulation of these metals in the sludge-amended soil. The main aspects of the study were the evaluation of 1) the extent of bioconcentration of heavy metals by the different kinds of plants, and 2) the availability of the metals from soil to plants, following sludge application. Field investigations involving plot-scale gardening were conducted using the two types of sludge, at application rates of 0, 2.2, 4.4, 8.8, 17.6 and 70.4 tons/acre. At application rates of 17.6 and 70.4 tons/acre, delays in germination of seeds were observed in some instances, with no apparent adverse effects on the plant's later stages of life and the yield produced. The uptake of heavy metals from sludge-amended soil by plants did not increase in direct proportion to the increase in rate of sludge application and plant species differ considerably in their uptake of heavy metals from soil which received the same amount of sludge. In general, plants grown on anaerobically digested sludge-applied soil showed higher uptake of heavy metals than those grown on aerobically digested sludge. Among the plants investigated, sweet corn was identified to be the low accumulator of heavy metals in the edible part of the plant.

  17. Dissolved organic matter removal during coal slag additive soil aquifer treatment for secondary effluent recharging: Contribution of aerobic biodegradation.

    PubMed

    Wei, Liangliang; Li, Siliang; Noguera, Daniel R; Qin, Kena; Jiang, Junqiu; Zhao, Qingliang; Kong, Xiangjuan; Cui, Fuyi

    2015-06-01

    Recycling wastewater treatment plant (WWTP) effluent at low cost via the soil aquifer treatment (SAT), which has been considered as a renewable approach in regenerating potable and non-potable water, is welcome in arid and semi-arid regions throughout the world. In this study, the effect of a coal slag additive on the bulk removal of the dissolved organic matter (DOM) in WWTP effluent during SAT operation was explored via the matrix configurations of both coal slag layer and natural soil layer. Azide inhibition and XAD-resins fractionation experiments indicated that the appropriate configuration designing of an upper soil layer (25 cm) and a mixture of soil/coal slag underneath would enhance the removal efficiency of adsorption and anaerobic biodegradation to the same level as that of aerobic biodegradation (31.7% vs 32.2%), while it was only 29.4% compared with the aerobic biodegradation during traditional 50 cm soil column operation. The added coal slag would preferentially adsorb the hydrophobic DOM, and those adsorbed organics could be partially biodegraded by the biomass within the SAT systems. Compared with the relatively lower dissolved organic carbon (DOC), ultraviolet light adsorption at 254 nm (UV-254) and trihalomethane formation potential (THMFP) removal rate of the original soil column (42.0%, 32.9%, and 28.0%, respectively), SSL2 and SSL4 columns would enhance the bulk removal efficiency to more than 60%. Moreover, a coal slag additive in the SAT columns could decline the aromatic components (fulvic-like organics and tryptophan-like proteins) significantly. PMID:25845997

  18. Dissolved organic matter removal during coal slag additive soil aquifer treatment for secondary effluent recharging: Contribution of aerobic biodegradation.

    PubMed

    Wei, Liangliang; Li, Siliang; Noguera, Daniel R; Qin, Kena; Jiang, Junqiu; Zhao, Qingliang; Kong, Xiangjuan; Cui, Fuyi

    2015-06-01

    Recycling wastewater treatment plant (WWTP) effluent at low cost via the soil aquifer treatment (SAT), which has been considered as a renewable approach in regenerating potable and non-potable water, is welcome in arid and semi-arid regions throughout the world. In this study, the effect of a coal slag additive on the bulk removal of the dissolved organic matter (DOM) in WWTP effluent during SAT operation was explored via the matrix configurations of both coal slag layer and natural soil layer. Azide inhibition and XAD-resins fractionation experiments indicated that the appropriate configuration designing of an upper soil layer (25 cm) and a mixture of soil/coal slag underneath would enhance the removal efficiency of adsorption and anaerobic biodegradation to the same level as that of aerobic biodegradation (31.7% vs 32.2%), while it was only 29.4% compared with the aerobic biodegradation during traditional 50 cm soil column operation. The added coal slag would preferentially adsorb the hydrophobic DOM, and those adsorbed organics could be partially biodegraded by the biomass within the SAT systems. Compared with the relatively lower dissolved organic carbon (DOC), ultraviolet light adsorption at 254 nm (UV-254) and trihalomethane formation potential (THMFP) removal rate of the original soil column (42.0%, 32.9%, and 28.0%, respectively), SSL2 and SSL4 columns would enhance the bulk removal efficiency to more than 60%. Moreover, a coal slag additive in the SAT columns could decline the aromatic components (fulvic-like organics and tryptophan-like proteins) significantly.

  19. High-quality draft genome sequence of Enterobacter sp. Bisph2, a glyphosate-degrading bacterium isolated from a sandy soil of Biskra, Algeria.

    PubMed

    Benslama, Ouided; Boulahrouf, Abderrahmane

    2016-06-01

    Enterobacter sp. strain Bisph2 was isolated from a sandy soil from Biskra, Algeria and exhibits glyphosate-degrading activity. Multilocus sequence analysis of the 16S rRNA, rpoB, hsp60, gyrB and dnaJ genes demonstrated that Bisph2 might be a member of a new species of the genus Enterobacter. Genomic sequencing of Bisph2 was used to better clarify the relationships among Enterobacter species. Annotation and analysis of the genome sequence showed that the 5.535.656 bp genome of Enterobacter sp. Bisph2 consists in one chromosome and no detectable plasmid, has a 53.19% GC content and 78% of genes were assigned a putative function. The genome contains four prophages of which 3 regions are intact and no CRISPER was detected. The nucleotide sequence of this genome was deposited into DDBJ/EMBL/GenBank under the accession JXAF00000000. PMID:27222800

  20. High-quality draft genome sequence of Enterobacter sp. Bisph2, a glyphosate-degrading bacterium isolated from a sandy soil of Biskra, Algeria.

    PubMed

    Benslama, Ouided; Boulahrouf, Abderrahmane

    2016-06-01

    Enterobacter sp. strain Bisph2 was isolated from a sandy soil from Biskra, Algeria and exhibits glyphosate-degrading activity. Multilocus sequence analysis of the 16S rRNA, rpoB, hsp60, gyrB and dnaJ genes demonstrated that Bisph2 might be a member of a new species of the genus Enterobacter. Genomic sequencing of Bisph2 was used to better clarify the relationships among Enterobacter species. Annotation and analysis of the genome sequence showed that the 5.535.656 bp genome of Enterobacter sp. Bisph2 consists in one chromosome and no detectable plasmid, has a 53.19% GC content and 78% of genes were assigned a putative function. The genome contains four prophages of which 3 regions are intact and no CRISPER was detected. The nucleotide sequence of this genome was deposited into DDBJ/EMBL/GenBank under the accession JXAF00000000.

  1. Effects of Monotypic and Binary Mixtures of Metal Oxide Nanoparticles on Microbial Growth in Sandy Soil Collected from Artificial Recharge Sites

    PubMed Central

    Ko, Kyung-Seok; Ha, Kyoochul; Kong, In Chul

    2015-01-01

    The potential effects of monotypic and binary metal oxide nanoparticles (NPs, ZnO, NiO, Co3O4 and TiO2) on microbial growth were evaluated in sandy soil collected from artificial recharge sites. Microbial growth was assessed based on adenosine triphosphate (ATP) content, dehydrogenase activity (DHA), and viable cell counts (VCC). Microbial growth based on ATP content and VCC showed considerable differences depending on NP type and concentration, whereas DHA did not significantly change. In general, ZnO NPs showed the strongest effect on microbial growth in all measurements, showing an EC50 value of 10.9 mg/L for ATP content. The ranking (EC50) of NPs based on their effect on microbial growth assessed by ATP content and VCC was ZnO > Co3O4 > NiO > TiO2. Upon exposure to binary NP mixtures, synergistic and additive modes of action were observed for ATP content and VCC, respectively. The ranges of observed (P(O)) and expected (P(E)) activity were 83%–92% and 78%–82% of the control (p-value 0.0010) based on ATP content and 78%–95% and 72%–94% of the control (p-value 0.8813) based on VCC under the tested conditions, respectively. The results indicate that the effects of NP mixtures on microbial growth in the sandy soil matrix were as great, or greater, than those of single NPs. Therefore, understanding the effects of single NPs and NP mixtures is essential for proper ecological risk assessment. Additionally, these findings demonstrate that the evaluation of NP effects may be profoundly influenced by the method of microbial growth measurement. PMID:26610489

  2. Effect of hydrogel particle additives on water-accessible pore structure of sandy soils: a custom pressure plate apparatus and capillary bundle model.

    PubMed

    Wei, Y; Durian, D J

    2013-05-01

    To probe the effects of hydrogel particle additives on the water-accessible pore structure of sandy soils, we introduce a custom pressure plate method in which the volume of water expelled from a wet granular packing is measured as a function of applied pressure. Using a capillary bundle model, we show that the differential change in retained water per pressure increment is directly related to the cumulative cross-sectional area distribution f(r) of the water-accessible pores with radii less than r. This is validated by measurements of water expelled from a model sandy soil composed of 2-mm-diameter glass beads. In particular, it is found that the expelled water is dramatically dependent on sample height and that analysis using the capillary bundle model gives the same pore size distribution for all samples. The distribution is found to be approximately log normal, and the total cross-sectional area fraction of the accessible pore space is found to be f(0)=0.34. We then report on how the pore distribution and total water-accessible area fraction are affected by superabsorbent hydrogel particle additives, uniformly mixed into a fixed-height sample at varying concentrations. Under both fixed volume and free swelling conditions, the total area fraction of water-accessible pore space in a packing decreases exponentially as the gel concentration increases. The size distribution of the pores is significantly modified by the swollen hydrogel particles, such that large pores are clogged while small pores are formed.

  3. Effects of Monotypic and Binary Mixtures of Metal Oxide Nanoparticles on Microbial Growth in Sandy Soil Collected from Artificial Recharge Sites.

    PubMed

    Ko, Kyung-Seok; Ha, Kyoochul; Kong, In Chul

    2015-01-01

    The potential effects of monotypic and binary metal oxide nanoparticles (NPs, ZnO, NiO, Co₃O₄ and TiO₂) on microbial growth were evaluated in sandy soil collected from artificial recharge sites. Microbial growth was assessed based on adenosine triphosphate (ATP) content, dehydrogenase activity (DHA), and viable cell counts (VCC). Microbial growth based on ATP content and VCC showed considerable differences depending on NP type and concentration, whereas DHA did not significantly change. In general, ZnO NPs showed the strongest effect on microbial growth in all measurements, showing an EC50 value of 10.9 mg/L for ATP content. The ranking (EC50) of NPs based on their effect on microbial growth assessed by ATP content and VCC was ZnO > Co₃O₄ > NiO > TiO₂. Upon exposure to binary NP mixtures, synergistic and additive modes of action were observed for ATP content and VCC, respectively. The ranges of observed (P(O)) and expected (P(E)) activity were 83%-92% and 78%-82% of the control (p-value 0.0010) based on ATP content and 78%-95% and 72%-94% of the control (p-value 0.8813) based on VCC under the tested conditions, respectively. The results indicate that the effects of NP mixtures on microbial growth in the sandy soil matrix were as great, or greater, than those of single NPs. Therefore, understanding the effects of single NPs and NP mixtures is essential for proper ecological risk assessment. Additionally, these findings demonstrate that the evaluation of NP effects may be profoundly influenced by the method of microbial growth measurement. PMID:26610489

  4. Accumulation of hexahydro-1,3,5-trinitro-1,3,5-triazine by the earthworm Eisenia andrei in a sandy loam soil.

    PubMed

    Sarrazin, Manon; Dodard, Sabine G; Savard, Kathleen; Lachance, Bernard; Robidoux, Pierre Y; Kuperman, Roman G; Hawari, Jalal; Ampleman, Guy; Thiboutot, Sonia; Sunahara, Geoffrey I

    2009-10-01

    The heterocyclic polynitramine hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a highly energetic compound found as a soil contaminant at some defense installations. Although RDX is not lethal to soil invertebrates at concentrations up to 10,000 mg/kg, it decreases earthworm cocoon formation and juvenile production at environmentally relevant concentrations found at contaminated sites. Very little is known about the uptake of RDX in earthworms and the potential risks for food-chain transfer of RDX in the environment. Toxicokinetic studies were conducted to quantify the bioaccumulation factors (BAFs) using adult earthworms (Eisenia andrei) exposed for up to 14 d to sublethal concentrations of nonlabeled RDX or [14C]RDX in a Sassafras sandy loam soil. High-performance liquid chromatography of acetonitrile extracts of tissue and soil samples indicated that nonlabeled RDX can be accumulated by the earthworm in a concentration- and time-dependent manner. The BAF, expressed as the earthworm tissue to soil concentration ratio, decreased from 6.7 to 0.1 when the nominal soil RDX concentrations were increased from 1 to 10,000 mg/kg. Tissue concentrations were comparable in earthworms exposed to nonlabeled RDX or [14C]RDX. The RDX bioaccumulation also was estimated using the kinetically derived model (BAFK), based on the ratio of the uptake to elimination rate constants. The established BAFK of 3.6 for [14C]RDX uptake was consistent with the results for nonlabeled RDX. Radioactivity also was present in the tissue residues of [14C]RDX-exposed earthworms following acetonitrile extraction, suggesting the formation of nonextractable [14C]RDX metabolites associated with tissue macromolecules. These findings demonstrated a net accumulation of RDX in the earthworm and the potential for food-chain transfer of RDX to higher-trophic-level receptors.

  5. Irrigation-induced changes in phosphorus fractions of Caribou sandy loam soil under different potato cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sequential fractionation is a common method used in evaluating the impacts of soil management practices on soil P distribution. However, to our knowledge, this method has not been used in investigating the effects of irrigation on the changes in soil P fractions. In this work, we measured sequentia...

  6. An integrated anaerobic/aerobic bioprocess for the remediation of chlorinated phenol-contaminated soil and groundwater.

    PubMed

    Ehlers, George A; Rose, Peter D

    2006-07-01

    An investigation of biodegradation of chlorinated phenol in an anaerobic/aerobic bioprocess environment was made. The reactor configuration used consisted of linked anaerobic and aerobic reactors, which served as a model for a proposed bioremediation strategy. The proposed strategy was studied in two reactors before linkage. In the anaerobic compartment, the transformation of the model contaminant, 2,4,6-trichlorophenol (2,4,6-TCP), to lesser-chlorinated metabolites was shown to occur during reductive dechlorination under sulfate-reducing conditions. The consortium was also shown to desorb and mobilize 2,4,6-TCP in soils. This was followed, in the aerobic compartment, by biodegradation of the pollutant and metabolites, 2,4-dichlorophenol, 4-chlorophenol, and phenol, by immobilized white-rot fungi. The integrated process achieved elimination of the compound by more than 99% through fungal degradation of metabolites produced in the dechlorination stage. pH correction to the anaerobic reactor was found to be necessary because acidic effluent from the fungal reactor inhibited sulfate reduction and dechlorination.

  7. Microbial response to salinity stress in a tropical sandy soil amended with native shrub residues or inorganic fertilizer.

    PubMed

    Sall, Saïdou Nourou; Ndour, Ndèye Yacine Badiane; Diédhiou-Sall, Siré; Dick, Richard; Chotte, Jean-Luc

    2015-09-15

    Soil degradation and salinization caused by inappropriate cultivation practices and high levels of saltwater intrusion are having an adverse effect on agriculture in Central Senegal. The residues of Piliostigma reticulatum, a local shrub that coexists with crops, were recently shown to increase particulate organic matter and improve soil quality and may be a promising means of alleviating the effects of salinization. This study compared the effects of inorganic fertilizer and P. reticulatum residues on microbial properties and the ability of soil to withstand salinity stress. We hypothesized that soils amended with P. reticulatum would be less affected by salinity stress than soils amended with inorganic fertilizer and control soil. Salinity stress was applied to soil from a field site that had been cultivated for 5 years under a millet/peanut crop rotation when microbial biomass, phospholipid fatty acid (PLFA) community profile, catabolic diversity, microbial activities were determined. Microbial biomass, nitrification potential and dehydrogenase activity were higher by 20%, 56% and 69% respectively in soil with the organic amendment. With salinity stress, the structure and activities of the microbial community were significantly affected. Although the biomass of actinobacteria community increased with salinity stress, there was a substantial reduction in microbial activity in all soils. The soil organically amended was, however, less affected by salinity stress than the control or inorganic fertilizer treatment. This suggests that amendment using P. reticulatum residues may improve the ability of soils to respond to saline conditions.

  8. Aerobic bioremediation of chlorobenzene source-zone soil in flow-through columns: performance assessment using quantitative PCR.

    PubMed

    Dominguez, Rosa F; da Silva, Marcio L B; McGuire, Travis M; Adamson, David; Newell, Charles J; Alvarez, Pedro J J

    2008-07-01

    Flow-through aquifer columns were operated for 12 weeks to evaluate the benefits of aerobic biostimulation for the bioremediation of source-zone soil contaminated with chlorobenzenes (CBs). Quantitative Polymerase Chain Reaction (qPCR) was used to measure the concentration of total bacteria (16S rRNA gene) and oxygenase genes involved in the biodegradation of aromatic compounds (i.e., toluene dioxygenase, ring hydroxylating monooxygenase, naphthalene dioxygenase, phenol hydroxylase, and biphenyl dioxygenase). Monochlorobenzene, which is much more soluble than dichlorobenzenes, was primarily removed by flushing, and biostimulation showed little benefit. In contrast, dichlorobenzene removal was primarily due to biodegradation, and the removal efficiency was much higher in oxygen-amended columns compared to a control column. To our knowledge, this is the first report that oxygen addition can enhance CB source-zone soil bioremediation. Analysis by qPCR showed that whereas the biphenyl and toluene dioxygenase biomarkers were most abundant, increases in the concentration of the phenol hydroxylase gene reflected best the higher dichlorobenzene removal due to aerobic biostimulation. This suggests that quantitative molecular microbial ecology techniques could be useful to assess CB source-zone bioremediation performance.

  9. Quantity and nature of water-extractable organic matter from sandy loam soils with potato cropping managements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Water-extractable organic matter (WEOM) is part of the soil labile organic matter components. In this work, we evaluated the level and nature of soil WEOM from a long-term (6-year) potato crop rotation field experiment. The contents of water-extractable organic C (WEOC) were higher in continuous pot...

  10. [High aluminum concentrations in well water of southern Lower Saxony sandy soil areas caused by acid precipitation--evaluation from the public health and ecologic viewpoint].

    PubMed

    Mühlenberg, W

    1990-01-01

    Decades of acid precipitation have caused soil acidification in regions with low neutralizing capacity of industrial countries, thus mobilizing aluminium from clay minerals into soil solution and ground water. In the southern sandy heath-land of Lower Saxony all the wells with pH values lower than 4.5 showed aluminium contents higher than 2.0 mg/l. 66.7% of the specimens within the pH-range 4.5 to 5.0 and 20% of the specimens within the pH-range 5.0 to 5.5 had aluminium levels of more than 0.2 mg/l, that is the maximum permissible limit value of the drinking water regulation. High contents of aluminium in drinking water are objectionable from the hygienic point of view, as they may cause intoxications in infants and patients with impaired renal function. In addition to this, the involvement of aluminium in the pathogenesis of severe degenerative disorders of the central nervous system cannot be excluded, such as Alzheimers disease, amyotrophic lateral sclerosis and Parkinsons dementia.

  11. [Characteristics of N2, N2O, NO, CO2 and CH4 Emissions in Anaerobic Condition from Sandy Loam Paddy Soil].

    PubMed

    Cao, Na; Wang, Rui; Liao, Ting-ting; Chen, Nuo; Zheng, Xun-hua; Yao, Zhi-sheng; Zhang, Hai; Butterbach-Bahl, Klaus

    2015-09-01

    Understanding the characteristics of the production of nitrogen gases (N2, N2O and NO), CO2 and CH4 in anaerobic paddy soils is not only a prerequisite for an improved mechanistic understanding of key microbial processes involved in the production of atmospheric greenhouse gases (GHG), but might also provide the basis for designing greenhouse gas mitigation strategies. Moreover, quantifying the composition fractions of denitrification gaseous products is of key importance for improving parameterization schemes of microbial processes in process-oriented models which are increasingly used for assessing soil GHG emissions at site and national scales. In our experiments we investigated two sandy loam soils from two paddy fields. The initial concentrations of soil nitrate and dissolved organic carbon (DOC) were set at approximately 50 mg.kg-1 and mg.kg-1, respectively, by adding a mixture solution of KNO3 and glucose. The emissions of N2, N2O NO, CO2 and CH4, as well as concentrations of carbon and nitrogen substrates for each soil sample were measured simultaneously, using a gas-flow-soil-core technique and a paralleling substrate monitoring system. The results showed that the accumulative emissions of N2, N2O and NO of the two soil samples for the entire incubation period were 6 - 8, 20, and 15 - 18 mg.kg-1, respectively. By measuring the cumulative emissions of denitrification gases (N, = N2 + N2O + NO) we were able to explain 95% to 98% of observed changes in s1ifr nilrate concentrations. The mass fractions of N2, N2O and NO emissions to Nt were approximately 15% -19%, 47% -49%, and 34% -36%, respectively. Thus, in our experiments N2O and NO were the main products of denitrification for the entire incubation period. However, as the temporal courses of hourly or daily production of the denitrification gases showed, NO production dominated and peaked firstly, and then N2O, before finally N2 became the dominant product. Our results show the high temporal dynamic of

  12. [Characteristics of N2, N2O, NO, CO2 and CH4 Emissions in Anaerobic Condition from Sandy Loam Paddy Soil].

    PubMed

    Cao, Na; Wang, Rui; Liao, Ting-ting; Chen, Nuo; Zheng, Xun-hua; Yao, Zhi-sheng; Zhang, Hai; Butterbach-Bahl, Klaus

    2015-09-01

    Understanding the characteristics of the production of nitrogen gases (N2, N2O and NO), CO2 and CH4 in anaerobic paddy soils is not only a prerequisite for an improved mechanistic understanding of key microbial processes involved in the production of atmospheric greenhouse gases (GHG), but might also provide the basis for designing greenhouse gas mitigation strategies. Moreover, quantifying the composition fractions of denitrification gaseous products is of key importance for improving parameterization schemes of microbial processes in process-oriented models which are increasingly used for assessing soil GHG emissions at site and national scales. In our experiments we investigated two sandy loam soils from two paddy fields. The initial concentrations of soil nitrate and dissolved organic carbon (DOC) were set at approximately 50 mg.kg-1 and mg.kg-1, respectively, by adding a mixture solution of KNO3 and glucose. The emissions of N2, N2O NO, CO2 and CH4, as well as concentrations of carbon and nitrogen substrates for each soil sample were measured simultaneously, using a gas-flow-soil-core technique and a paralleling substrate monitoring system. The results showed that the accumulative emissions of N2, N2O and NO of the two soil samples for the entire incubation period were 6 - 8, 20, and 15 - 18 mg.kg-1, respectively. By measuring the cumulative emissions of denitrification gases (N, = N2 + N2O + NO) we were able to explain 95% to 98% of observed changes in s1ifr nilrate concentrations. The mass fractions of N2, N2O and NO emissions to Nt were approximately 15% -19%, 47% -49%, and 34% -36%, respectively. Thus, in our experiments N2O and NO were the main products of denitrification for the entire incubation period. However, as the temporal courses of hourly or daily production of the denitrification gases showed, NO production dominated and peaked firstly, and then N2O, before finally N2 became the dominant product. Our results show the high temporal dynamic of

  13. Aerobic biodegradation of biphenyl and polychlorinated biphenyls by Arctic soil microorganisms.

    PubMed Central

    Mohn, W W; Westerberg, K; Cullen, W R; Reimer, K J

    1997-01-01

    We examined the degradation of biphenyl and the commercial polychlorinated biphenyl (PCB) mixture Aroclor 1221 by indigenous Arctic soil microorganisms to assess both the response of the soil microflora to PCB pollution and the potential of the microflora for bioremediation. In soil slurries, Arctic soil microflora and temperate-soil microflora had similar potentials to mineralize [14C]biphenyl. Mineralization began sooner and was more extensive in slurries of PCB-contaminated Arctic soils than in slurries of uncontaminated Arctic soils. The maximum mineralization rates at 30 and 7 degrees C were typically 1.2 to 1.4 and 0.52 to 1.0 mg of biphenyl g of dry soil-1 day-1, respectively. Slurries of PCB-contaminated Arctic soils degraded Aroclor 1221 more extensively at 30 degrees C (71 to 76% removal) than at 7 degrees C (14 to 40% removal). We isolated from Arctic soils organisms that were capable of psychrotolerant (growing at 7 to 30 degrees C) or psychrophilic (growing at 7 to 15 degrees C) growth on biphenyl. Two psychrotolerant isolates extensively degraded Aroclor 1221 at 7 degrees C (54 to 60% removal). The soil microflora and psychrotolerant isolates degraded all mono-, most di-, and some trichlorobiphenyl congeners. The results suggest that PCB pollution selected for biphenyl-mineralizing microorganisms in Arctic soils. While low temperatures severely limited Aroclor 1221 removal in slurries of Arctic soils, results with pure cultures suggest that more effective PCB biodegradation is possible under appropriate conditions. PMID:9292988

  14. Aerobic biodegradation of [14C] 6:2 fluorotelomer alcohol in a flow-through soil incubation system.

    PubMed

    Liu, Jinxia; Wang, Ning; Buck, Robert C; Wolstenholme, Barry W; Folsom, Patrick W; Sulecki, Lisa M; Bellin, Cheryl A

    2010-08-01

    The aerobic biodegradation of [1,2-(14)C] 6:2 FTOH [F(CF(2))(6)(14)CH(2)(14)CH(2)OH] in a flow-through soil incubation system is described. Soil samples dosed with [1,2-(14)C] 6:2 FTOH were analyzed by liquid scintillation counting, LC/ARC (liquid chromatography/accurate radioisotope counting), LC/MS/MS, and thermal combustion to account for 6:2 FTOH and its transformation products over 84 d. Half of the [1,2-(14)C] 6:2 FTOH disappeared from soil in 1.3 d, undergoing simultaneous microbial degradation and partitioning of volatile transformation product(s) and the 6:2 FTOH precursor into the air phase. The overall (14)C (radioactivity) mass balance in live and sterile treatments was 77-87% over 84-d incubation. In the live test system, 36% of total (14)C dosed was captured in the airflow (headspace), 25% as soil-bound residues recovered via thermal combustion, and 16% as soil extractable. After 84 d, [(14)C] 5:2 sFTOH [F(CF(2))(5)CH(OH)(14)CH(3)] was the dominant transformation product with 16% molar yield and primarily detected in the airflow. The airflow also contained [1,2-(14)C] 6:2 FTOH and (14)CO(2) at 14% and 6% of total (14)C dosed, respectively. The other significant stable transformation products, all detected in soil, were 5:3 acid [F(CF(2))(5)CH(2)CH(2)COOH, 12%], PFHxA [F(CF(2))(5)COOH, 4.5%] and PFPeA [F(CF(2))(4)COOH, 4.2%]. Soil-bound residues as well as conjugates between fluorinated transformation products and dissolved soil components were only observed in the live test system and absent in the sterile soil, suggesting that such binding and complexation are microbially or enzymatically driven processes. At day 84, 5:3 acid is postulated to be the major transformation product in soil-bound residues, which may not be available for further biodegradation in soil environment.

  15. Effects of Different Factors on Water Flow and Solute Transport Investigated by Time Domain Reflectometry in Sandy Clay Loam Field Soil.

    PubMed

    Merdun, Hasan

    2012-09-01

    Factors affecting preferential flow and transport in the vadose zone need to be investigated by experiments and simulations to protect groundwater against surface applied chemicals. The objectives of this study were to investigate the effects of several factors (soil structure, initial soil water content (SWC), and application rate) and their interactions on the extent of preferential flow and transport in a sandy clay loam field soil using the time domain reflectometry (TDR) for measuring SWC and electrical conductivity (EC) in 12 treatments, modeling (by HYDRUS-1D and VS2DTI) the measured SWC and EC, and conducting statistical tests for comparing the means of the measured and modeled SWC and EC and solute transport parameters (pore water velocity and dispersion coefficient) obtained by inversely fitting in the CXTFIT program. The study results showed that the applied solution moved faster in the undisturbed, wet initial SWC, and higher application rate experimental conditions than in the disturbed, dry initial SWC, and lower application rate, respectively, based on the analysis of the changes in TDR measured SWC and EC with depth at 1, 2, 5, and 15 h of the experiments. However, the effects of interactive factors or treatments on water flow and solute transport were not clear enough. The modeling results showed that HYDRUS-1D was better than VS2DTI in the estimation of EC and especially SWC, but overall the models had relatively low performances in the simulations. Statistical test results also showed that the treatments had different flow and transport characteristics because they were divided into different groups in terms of the means of SWC and EC and solute transport parameters. These results suggest that similar experiments with more distinct interactions and modeling studies with different approaches need to be considered for better understanding the complex flow and transport processes in the vadose zone. PMID:23002311

  16. A laboratory study of the bioremediation of 2,4,6-trinitrotoluene-contaminated soil using aerobic/anoxic soil slurry reactor.

    SciTech Connect

    Boopathy, R.; Manning, J.; Kulpa, C. F.; Environmental Research; Univ. of Notre Dame

    1998-01-01

    The successful operation of an aerobic/anoxic laboratory-scale soil slurry reactor showed that soil contaminated with 2,4,6-trinitrotoluene (TNT) and hexahydro-l,3,5-trinitro-l,3,5-triazine (RDX) could be treated in batches or semicontinuously. Batch treatment resulted in the transformation of TNT. Semicontinuous treatment resulted in complete degradation of TNT. In addition to removing TNT, the slurry reactor also removed contaminants such as trinitrobenzene, 2,4-dinitrotoluene, RDX, and octahydro-l,3,5,7-tetranitro-l,3,5,7-tetraazocine (HMX). Radiolabeled TNT incubated with reactor biomass showed that 23% of [{sup 14}C]TNT was mineralized, 27% was converted to biomass, and 8% was adsorbed onto the soil. The rest of the [{sup 14}C]TNT was accounted for as metabolites, including a ring cleavage product identified as 2,3-butanediol. Increasing the frequency of soil addition from once to two or three times weekly did not affect the TNT removal rates. The soil slurry reactor also maintained the bacterial population fairly well, needing only 0.3% molasses as a cosubstrate.

  17. Aerobic biotransformation of N-nitrosodimethylamine and N-nitrodimethylamine in methane and benzene amended soil columns.

    PubMed

    Weidhaas, Jennifer; Dupont, R Ryan

    2013-07-01

    Aerobic biotransformation of N-nitrosodimethylamine (NDMA), an emerging contaminant of concern, and its structural analog N-nitrodimethylamine (DMN), was evaluated in benzene and methane amended groundwater passed through laboratory scale soil columns. Competitive inhibition models were used to model the kinetics for NDMA and DMN cometabolism accounting for the concurrent degradation of the growth and cometabolic substrates. Transformation capacities for NDMA and DMN with benzene (13 and 23μg (mgcells)(-1)) and methane (0.14 and 8.4μg (mgcells)(-1)) grown cultures, respectively are comparable to those presented in the literature, as were first order endogenous decay rates estimated to be 2.1×10(-2)±1.7×10(-3)d(-1) and 6.5×10(-1)±7.1×10(-1)d(-1) for the methane and benzene amended cultures, respectively. These studies highlight possible attenuation mechanisms and rates for NDMA and DMN biotransformation in aerobic aquifers undergoing active remediation, natural attenuation or managed aquifer recharge with treated wastewater (i.e., reclaimed water).

  18. Speciation of organic matter in sandy soil size fractions as revealed by analytical pyrolysis (Py-GC/MS) and FT-IR spectroscopy

    NASA Astrophysics Data System (ADS)

    Jiménez-Morillo, Nicasio T.; González-Vila, Francisco J.; Jordán, Antonio; Zavala, Lorena M.; de la Rosa, José M.; González-Pérez, José A.

    2015-04-01

    This research deals with the assessment of organic matter structural differences in soil physical fractions before and after lipid extractions. Soil samples were collected in sandy soils, Arenosols (WRB 2006) from the Doñana National Park (SW Spain) under different vegetation cover: cork oak (Quercus suber, QS), eagle fern (Pteridium aquilinum, PA), pine (Pinus pinea, PP) and rockrose (Halimium halimifolium, HH). Two size fractions; coarse (C: 1-2 mm) and fine (F: 0.05-0.25 mm) were studied from each soil. . In addition, the two fractions from each soil were exhaustively Soxhlet extracted with a Dichlorometane-Methanol (3:1) mixture to obtain the lipid-free fractions (LF) from each size fraction (LFC and LFF). The composition of the organic matter at a molecular level in the different soil fractions was approached by analytical pyrolysis (Py-GC/MS) and FT-IR spectroscopy. These techniques are complementary and have been found suitable for the structural characterization of complex organic matrices (Moldoveanu, 1998; Piccolo and Stevenson, 1982); whereas Py-GC/MS provides detailed structural information of individual compounds present and a finger-printing of soil organic matter, FT-IR is informative about major functional groups present. The advantages of these techniques are well known: no need for pretreatment are fast to perform, highly reproducible and only small amount of samples are needed. Soil size fractions show contrasting differences in organic matter content (C 4-7 % and F > 40 %) and conspicuous differences were found in the pyrolysis products released by the fractions studied. The main families of pyrolysis compounds have well defined macromolecular precursors, such as lignin, polypeptides, polysaccharides and lipids (González-Vila et al., 2001). The C fractions yield higher relative abundance of lignin and polysaccharide derived pyrolysis compounds. Regarding the differences in the soil organic matter as affected by the different vegetation covers

  19. INDICATORS OF NITRATE LEACHING LOSS UNDER DIFFERENT LAND USE OF CLAYEY AND SANDY SOILS IN SOUTHEASTERN OKLAHOMA

    EPA Science Inventory

    Evidence of increasing nitrate (NO3-) leaching losses from soils under various land use systems has elevated the interest and need to find better land management practices. An essential step in developing new management practices is understanding of the com...

  20. Aerobic uranium (VI) bioprecipitation by metal-resistant bacteria isolated from radionuclide- and metal-contaminated subsurface soils.

    PubMed

    Martinez, Robert J; Beazley, Melanie J; Taillefert, Martial; Arakaki, Adrian K; Skolnick, Jeffrey; Sobecky, Patricia A

    2007-12-01

    In this study, the immobilization of toxic uranium [U(VI)] mediated by the intrinsic phosphatase activities of naturally occurring bacteria isolated from contaminated subsurface soils was examined. The phosphatase phenotypes of strains belonging to the genera, Arthrobacter, Bacillus and Rahnella, previously isolated from subsurface soils at the US Department of Energy's (DOE) Oak Ridge Field Research Center (ORFRC), were determined. The ORFRC represents a unique, extreme environment consisting of highly acidic soils with co-occurring heavy metals, radionuclides and high nitrate concentrations. Isolates exhibiting phosphatase-positive phenotypes indicative of constitutive phosphatase activity were subsequently tested in U(VI) bioprecipitation assays. When aerobically grown in synthetic groundwater (pH 5.5) amended with 10 mM glycerol-3-phosphate (G3P), phosphatase-positive Bacillus and Rahnella spp. strains Y9-2 and Y9602 liberated sufficient phosphate to precipitate 73% and 95% of total soluble U added as 200 microM uranyl acetate respectively. In contrast, an Arthrobacter sp. X34 exhibiting a phosphatase-negative phenotype did not liberate phosphate from G3P or promote U(VI) precipitation. This study provides the first evidence of U(VI) precipitation via the phosphatase activity of naturally occurring Bacillus and Rahnella spp. isolated from the acidic subsurface at the DOE ORFRC.

  1. Selenite reduction by the obligate aerobic bacterium Comamonas testosteroni S44 isolated from a metal-contaminated soil

    PubMed Central

    2014-01-01

    Background Selenium (Se) is an essential trace element in most organisms but has to be carefully handled since there is a thin line between beneficial and toxic concentrations. Many bacteria have the ability to reduce selenite (Se(IV)) and (or) selenate (Se(VI)) to red elemental selenium that is less toxic. Results A strictly aerobic bacterium, Comamonas testosteroni S44, previously isolated from metal(loid)-contaminated soil in southern China, reduced Se(IV) to red selenium nanoparticles (SeNPs) with sizes ranging from 100 to 200 nm. Both energy dispersive X-ray Spectroscopy (EDX or EDS) and EDS Elemental Mapping showed no element Se and SeNPs were produced inside cells whereas Se(IV) was reduced to red-colored selenium in the cytoplasmic fraction in presence of NADPH. Tungstate inhibited Se(VI) but not Se(IV) reduction, indicating the Se(IV)-reducing determinant does not contain molybdenum as co-factor. Strain S44 was resistant to multiple heavy and transition metal(loid)s such as Se(IV), As(III), Cu(II), and Cd(II) with minimal inhibitory concentrations (MIC) of 100 mM, 20 mM, 4 mM, and 0.5 mM, respectively. Disruption of iscR encoding a transcriptional regulator negatively impacted cellular growth and subsequent resistance to multiple heavy metal(loid)s. Conclusions C. testosteroni S44 could be very useful for bioremediation in heavy metal(loid) polluted soils due to the ability to both reduce toxic Se(VI) and Se(IV) to non-toxic Se (0) under aerobic conditions and to tolerate multiple heavy and transition metals. IscR appears to be an activator to regulate genes involved in resistance to heavy or transition metal(loid)s but not for genes responsible for Se(IV) reduction. PMID:25098921

  2. Influence of 20–Year Organic and Inorganic Fertilization on Organic Carbon Accumulation and Microbial Community Structure of Aggregates in an Intensively Cultivated Sandy Loam Soil

    PubMed Central

    Zhang, Huanjun; Ding, Weixin; He, Xinhua; Yu, Hongyan; Fan, Jianling; Liu, Deyan

    2014-01-01

    To evaluate the long–term effect of compost (CM) and inorganic fertilizer (NPK) application on microbial community structure and organic carbon (OC) accumulation at aggregate scale, soils from plots amended with CM, NPK and no fertilizer (control) for 20 years (1989–2009) were collected. Soil was separated into large macroaggregate (>2,000 μm), small macroaggregate (250–2,000 μm), microaggregate (53–250 μm), silt (2–53 μm) and clay fraction (<2 μm) by wet-sieving, and their OC concentration and phospholipid fatty acids (PLFA) were measured. The 20-year application of compost significantly (P<0.05) increased OC by 123–134% and accelerated the formation of macroaggregates, but decreased soil oxygen diffusion coefficient. NPK mainly increased OC in macroaggregates and displayed weaker influence on aggregation. Bacteria distributed in all aggregates, while fungi and actinobacteria were mainly in macroaggregates and microaggregates. The ratio of monounsaturated to branched (M/B) PLFAs, as an indicator for the ratio of aerobic to anaerobic microorganisms, increased inversely with aggregate size. Both NPK and especially CM significantly (P<0.05) decreased M/B ratios in all aggregates except the silt fraction compared with the control. The increased organic C in aggregates significantly (P<0.05) negatively correlated with M/B ratios under CM and NPK. Our study suggested that more efficient OC accumulations in aggregates under CM–treated than under NPK–treated soil was not only due to a more effective decrease of actinobacteria, but also a decrease of monounsaturated PLFAs and an increase of branched PLFAs. Aggregations under CM appear to alter micro-habitats to those more suitable for anaerobes, which in turn boosts OC accumulation. PMID:24667543

  3. Influence of 20-year organic and inorganic fertilization on organic carbon accumulation and microbial community structure of aggregates in an intensively cultivated sandy loam soil.

    PubMed

    Zhang, Huanjun; Ding, Weixin; He, Xinhua; Yu, Hongyan; Fan, Jianling; Liu, Deyan

    2014-01-01

    To evaluate the long-term effect of compost (CM) and inorganic fertilizer (NPK) application on microbial community structure and organic carbon (OC) accumulation at aggregate scale, soils from plots amended with CM, NPK and no fertilizer (control) for 20 years (1989-2009) were collected. Soil was separated into large macroaggregate (>2,000 μm), small macroaggregate (250-2,000 μm), microaggregate (53-250 μm), silt (2-53 μm) and clay fraction (<2 μm) by wet-sieving, and their OC concentration and phospholipid fatty acids (PLFA) were measured. The 20-year application of compost significantly (P<0.05) increased OC by 123-134% and accelerated the formation of macroaggregates, but decreased soil oxygen diffusion coefficient. NPK mainly increased OC in macroaggregates and displayed weaker influence on aggregation. Bacteria distributed in all aggregates, while fungi and actinobacteria were mainly in macroaggregates and microaggregates. The ratio of monounsaturated to branched (M/B) PLFAs, as an indicator for the ratio of aerobic to anaerobic microorganisms, increased inversely with aggregate size. Both NPK and especially CM significantly (P<0.05) decreased M/B ratios in all aggregates except the silt fraction compared with the control. The increased organic C in aggregates significantly (P<0.05) negatively correlated with M/B ratios under CM and NPK. Our study suggested that more efficient OC accumulations in aggregates under CM-treated than under NPK-treated soil was not only due to a more effective decrease of actinobacteria, but also a decrease of monounsaturated PLFAs and an increase of branched PLFAs. Aggregations under CM appear to alter micro-habitats to those more suitable for anaerobes, which in turn boosts OC accumulation.

  4. Nitrite-Driven Nitrous Oxide Production Under Aerobic Soil Conditions: Kinetics and Biochemical Controls

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrite (NO2-) can accumulate during nitrification in soil following fertilizer application. While the role of NO2- as a substrate regulating nitrous oxide (N2O) production is recognized, kinetic data are not available that allow for estimating N2O production or soil-to-atmosphere fluxes as a functi...

  5. Speciation of organic matter in sandy soil size fractions as revealed by analytical pyrolysis (Py-GC/MS) and FT-IR spectroscopy

    NASA Astrophysics Data System (ADS)

    Jiménez-Morillo, Nicasio T.; González-Vila, Francisco J.; Jordán, Antonio; Zavala, Lorena M.; de la Rosa, José M.; González-Pérez, José A.

    2015-04-01

    This research deals with the assessment of organic matter structural differences in soil physical fractions before and after lipid extractions. Soil samples were collected in sandy soils, Arenosols (WRB 2006) from the Doñana National Park (SW Spain) under different vegetation cover: cork oak (Quercus suber, QS), eagle fern (Pteridium aquilinum, PA), pine (Pinus pinea, PP) and rockrose (Halimium halimifolium, HH). Two size fractions; coarse (C: 1-2 mm) and fine (F: 0.05-0.25 mm) were studied from each soil. . In addition, the two fractions from each soil were exhaustively Soxhlet extracted with a Dichlorometane-Methanol (3:1) mixture to obtain the lipid-free fractions (LF) from each size fraction (LFC and LFF). The composition of the organic matter at a molecular level in the different soil fractions was approached by analytical pyrolysis (Py-GC/MS) and FT-IR spectroscopy. These techniques are complementary and have been found suitable for the structural characterization of complex organic matrices (Moldoveanu, 1998; Piccolo and Stevenson, 1982); whereas Py-GC/MS provides detailed structural information of individual compounds present and a finger-printing of soil organic matter, FT-IR is informative about major functional groups present. The advantages of these techniques are well known: no need for pretreatment are fast to perform, highly reproducible and only small amount of samples are needed. Soil size fractions show contrasting differences in organic matter content (C 4-7 % and F > 40 %) and conspicuous differences were found in the pyrolysis products released by the fractions studied. The main families of pyrolysis compounds have well defined macromolecular precursors, such as lignin, polypeptides, polysaccharides and lipids (González-Vila et al., 2001). The C fractions yield higher relative abundance of lignin and polysaccharide derived pyrolysis compounds. Regarding the differences in the soil organic matter as affected by the different vegetation covers

  6. Effects of a novel poly (AA-co-AAm)/AlZnFe₂O₄/potassium humate superabsorbent hydrogel nanocomposite on water retention of sandy loam soil and wheat seedling growth.

    PubMed

    Shahid, Shaukat Ali; Qidwai, Ansar Ahmad; Anwar, Farooq; Ullah, Inam; Rashid, Umer

    2012-01-01

    A novel poly(acrylic acid-co-acrylamide)AlZnFe₂O₄/potassium humate( )superabsorbent hydrogel nanocomposite (PHNC) was synthesized and its physical properties characterized using SEM, Energy Dispersive X-ray (EDX) and FTIR spectroscopic techniques. Air dried sandy loam soil was amended with 0.1 to 0.4 w/w% of PHNC to evaluate its soil moisture retention attributes. Effect of PHNC amendment on pH, electrical conductivity (EC), porosity, bulk density and hydraulic conductivity of sandy loam soil was also studied. The soil amendment with 0.1 to 0.4 w/w% of PHNC remarkably enhanced the moisture retention at field capacity as compared to the un-amended soils. Seed germination and seedling growth of wheat (Triticum aestivum L.) was considerably increased and a delay by 6-9 days in wilting of seedlings was observed in the soil amended with PHNC, resulting in improved wheat plant establishment and growth. PMID:23099615

  7. Aerobic Bioremediation of PAH Contaminated Soil Results in Increased Genotoxicity and Developmental Toxicity.

    PubMed

    Chibwe, Leah; Geier, Mitra C; Nakamura, Jun; Tanguay, Robert L; Aitken, Michael D; Simonich, Staci L Massey

    2015-12-01

    The formation of more polar and toxic polycyclic aromatic hydrocarbon (PAH) transformation products is one of the concerns associated with the bioremediation of PAH-contaminated soils. Soil contaminated with coal tar (prebioremediation) from a former manufactured gas plant (MGP) site was treated in a laboratory scale bioreactor (postbioremediation) and extracted using pressurized liquid extraction. The soil extracts were fractionated, based on polarity, and analyzed for 88 PAHs (unsubstituted, oxygenated, nitrated, and heterocyclic PAHs). The PAH concentrations in the soil tested, postbioremediation, were lower than their regulatory maximum allowable concentrations (MACs), with the exception of the higher molecular weight PAHs (BaA, BkF, BbF, BaP, and IcdP), most of which did not undergo significant biodegradation. The soil extract fractions were tested for genotoxicity using the DT40 chicken lymphocyte bioassay and developmental toxicity using the embryonic zebrafish (Danio rerio) bioassay. A statistically significant increase in genotoxicity was measured in the unfractionated soil extract, as well as in four polar soil extract fractions, postbioremediation (p < 0.05). In addition, a statistically significant increase in developmental toxicity was measured in one polar soil extract fraction, postbioremediation (p < 0.05). A series of morphological abnormalities, including peculiar caudal fin malformations and hyperpigmentation in the tail, were measured in several soil extract fractions in embryonic zebrafish, both pre- and postbioremediation. The increased toxicity measured postbioremediation is not likely due to the 88 PAHs measured in this study (including quinones), because most were not present in the toxic polar fractions and/or because their concentrations did not increase postbioremediation. However, the increased toxicity measured postbioremediation is likely due to hydroxylated and carboxylated transformation products of the 3- and 4-ring PAHs (PHE, 1

  8. Runoff and leaching of atrazine and alachlor on a sandy soil as affected by application in sprinkler irrigation.

    PubMed

    Abdel-Rahman, A R; Wauchope, R D; Truman, C C; Dowler, C C

    1999-05-01

    Rainfall simulation was used with small packed boxes of soil to compare runoff of herbicides applied by conventional spray and injection into sprinkler-irrigation (chemigation), under severe rainfall conditions. It was hypothesized that the larger water volumes used in chemigation would leach some of the chemicals out of the soil surface rainfall interaction zone, and thus reduce the amounts of herbicides available for runoff. A 47-mm rain falling in a 2-hour event 24 hours after application of alachlor (2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)-acetamide) and atrazine (6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2, 4-diamine) was simulated. The design of the boxes allowed a measurement of pesticide concentrations in splash water throughout the rainfall event. Initial atrazine concentrations exceeding its' solubility were observed. When the herbicides were applied in 64,000 L/ha of water (simulating chemigation in 6.4 mm irrigation water) to the surface of a Tifton loamy sand, subsequent herbicide losses in runoff water were decreased by 90% for atrazine and 91% for alachlor, as compared to losses from applications in typical carrier water volumes of 187 L/ha. However, this difference was not due to an herbicide leaching effect but to a 96% decrease in the amount of runoff from the chemigated plots. Only 0.3 mm of runoff occurred from the chemigated boxes while 7.4 mm runoff occurred from the conventionally-treated boxes, even though antecedent moisture was higher in the former. Two possible explanations for this unexpected result are (a) increased aggregate stability in the more moist condition, leading to less surface sealing during subsequent rainfall, or (b) a hydrophobic effect in the drier boxes. In the majority of these pans herbicide loss was much less in runoff than in leachate water. Thus, in this soil, application of these herbicides by chemigation would decrease their potential for pollution only in situations where runoff is a greater

  9. Runoff and leaching of atrazine and alachlor on a sandy soil as affected by application in sprinkler irrigation.

    PubMed

    Abdel-Rahman, A R; Wauchope, R D; Truman, C C; Dowler, C C

    1999-05-01

    Rainfall simulation was used with small packed boxes of soil to compare runoff of herbicides applied by conventional spray and injection into sprinkler-irrigation (chemigation), under severe rainfall conditions. It was hypothesized that the larger water volumes used in chemigation would leach some of the chemicals out of the soil surface rainfall interaction zone, and thus reduce the amounts of herbicides available for runoff. A 47-mm rain falling in a 2-hour event 24 hours after application of alachlor (2-chloro-N-(2,6-diethylphenyl)-N-(methoxymethyl)-acetamide) and atrazine (6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2, 4-diamine) was simulated. The design of the boxes allowed a measurement of pesticide concentrations in splash water throughout the rainfall event. Initial atrazine concentrations exceeding its' solubility were observed. When the herbicides were applied in 64,000 L/ha of water (simulating chemigation in 6.4 mm irrigation water) to the surface of a Tifton loamy sand, subsequent herbicide losses in runoff water were decreased by 90% for atrazine and 91% for alachlor, as compared to losses from applications in typical carrier water volumes of 187 L/ha. However, this difference was not due to an herbicide leaching effect but to a 96% decrease in the amount of runoff from the chemigated plots. Only 0.3 mm of runoff occurred from the chemigated boxes while 7.4 mm runoff occurred from the conventionally-treated boxes, even though antecedent moisture was higher in the former. Two possible explanations for this unexpected result are (a) increased aggregate stability in the more moist condition, leading to less surface sealing during subsequent rainfall, or (b) a hydrophobic effect in the drier boxes. In the majority of these pans herbicide loss was much less in runoff than in leachate water. Thus, in this soil, application of these herbicides by chemigation would decrease their potential for pollution only in situations where runoff is a greater

  10. Diastereoselective metabolism of a novel cis-nitromethylene neonicotinoid paichongding in aerobic soils.

    PubMed

    Fu, Qiuguo; Zhang, Jianbo; Xu, Xiaoyong; Wang, Haiyan; Wang, Wei; Ye, Qingfu; Li, Zhong

    2013-09-17

    Many pesticides are chiral but used as racemic mixtures, even though their stereoisomers are often degraded stereoselectively in soils. Evaluation of degradation of chiral compounds is mostly focused on the enantioselectivity rather than diastereoselectivity/epimer preferences. In this study, we explored the diastereoselective transformation of paichongding (IPP), a novel chiral neonicotinoid with broad-spectrum insecticidal activity, to several degradation intermediates in different soils. (14)C-Labeling coupled with LC-MS/MS and high resolution MS were used to track residues of IPP and identify major transformation metabolites. The stereoisomers of IPP known as 5R, 7R-IPP (RR-IPP), 5S, 7S-IPP (SS-IPP), 5S, 7R-IPP (SR-IPP), and 5R, 7S-IPP (RS-IPP) showed diastereoselective/epimer-selective persistence in all soils except an acidic clay soil. Moreover, IPP was transformed to a range of degradation intermediates (M1-M6), which also showed significant diastereoselective and soil preferential formation. Depropylation, nitrosylation, denitration, demethylation, dehydroxylation, and ketonization contributed to IPP transformation. The diastereoselective degradation of the parent compound and formation of incomplete intermediates implies that diastereomers/epimers should be regarded as different chemicals. The approach of coupling (14)C and MS may be used as an effective tool to understand the environmental processes and risks of other man-made chiral compounds. PMID:23924365

  11. Contribution of nitrous oxide and methan to the overall climate impact of maize on well-drained sandy soils of north-east Germany

    NASA Astrophysics Data System (ADS)

    Andres, M.; Hagemann, U.; Pohl, M.; Sommer, M.; Augustin, J.

    2012-04-01

    Erosion effects and the influence of organic fertiliser (fermentation residues, FR) on the climate impact and greenhouse gas (GHG) emissions of N2O, CH4 and CO2 were investigated at an experimental field side in the lowlands of north-east Germany during the years 2010 and 2011. This intensively used agricultural landscape is glacially shaped and characterized by well-drained sandy and loamy soils. Erosion effects on GHG exchange were investigated for energy maize at the CarboZALF-D project site near Dedelow, Uckermark. In addition to a non-eroded haplic luvisol (reference), emissions were measured for three eroded soil types: a) eroded haplic luvisol, b) haplic regosol (calcaric) and c) endogleyic colluvic regosol (deposition side). In a second field trial, the impact of organic fertilization on GHG emissions was assessed for a range of FR fertilization (0-200% N) and compared to a non-fertilized and a minerally fertilized control. Only 70% of the N content of the FR was assumed to be available for plants. Discontinuous measurements of N2O and CH4 were carried out bi-weekly using the closed-chamber method and 20-minute interval sampling. Gas samples were analysed using a gas chromatograph. Gas fluxes were calculated using linear regression, interpolated and finally cumulated. CO2 flux measurements of ecosystem respiration (Reco) and net ecosystem exchange (NEE) were conducted every four weeks by using a non-flow-through non-steady-state closed chamber system (Livingston and Hutchinson 1995) based on Drösler (2005). Measurement gaps of NEE were filled by modeling the Reco fluxes using the Lloyd-Taylor (Lloyd and Taylor 1994) method and the gross primary production (GPP) fluxes using Michaelis-Menten (Michaelis and Menten 1913) modeling approach. Annual NEE balances were then calculated based on the modeled Reco and GPP fluxes. All investigated soil types were C sinks, storing up to 9,6 t CO2eq ha-1 yr-1. As expected for this well-drained soils, the climate impact

  12. [Hydraulic limitation on photosynthetic rate of old Populus simonii trees in sandy soil of north Shaanxi Province].

    PubMed

    Zuo, Li-Xiang; Li, Yang-Yang; Chen, Jia-Cun

    2014-06-01

    'Old and dwarf trees' on the loess plateau region mainly occurred among mature trees rather than among small trees. To elucidate the mechanism of tree age on 'old and dwarf trees' formation, taking Populus simonii, a tree species that accounted for the largest portion of 'old and dwarf trees' on the loess plateau, as an example, the growth, photosynthesis and hydraulic traits of P. simonii trees with different ages (young: 13-15 years, mid-aged: 31-34 years, and old: 49-54 years) were measured. The results showed that the dieback length increased, and net photosynthetic rate, stomatal conductance, transpiration rate, and whole plant hydraulic conductance decreased significantly with the increasing tree age. Both net photosynthetic rate and stomatal conductance measured at different dates were significantly and positively related to the whole plant hydraulic conductance, suggesting that the decreasing photosynthetic rate of old trees was possibly caused by the declined hydraulic conductance. Although the resistance to cavitation in stems and leaves was stronger in old trees than in young and mid-aged trees, there were no differences in midday native stem embolization degree and leaf hydraulic conductance based on the vulnerability curve estimation, suggesting that the increased hydraulic resistance of the soil-root system is probably the most important reason for decreasing the whole plant hydraulic conductance of old trees.

  13. Leaching behaviour of pendimethalin causes toxicity towards different cultivars of Brassica juncea and Brassica campestris in sandy loam soil

    PubMed Central

    Bandyopadhyay, Subhendu; Choudhury, Partha P.

    2009-01-01

    An experiment was conducted at the farm of Zonal Adaptive Research Station, Uttar Banga Krishi Viswavidhyalaya, Pundibari, Cooch Behar, West Bengal to evaluate the effect of pendimethalin on the yield, weed density and phytotoxicity in different varieties of rai (Brassica juncea) and yellow sarson (B. campestris var. yellow sarson) under higher soil moisture regime in Terai region of West Bengal. Pre-emergence application of pendimethalin at higher dose i.e. 1.0 kg/ha recorded higher plant mortality (30.92%) due to the presence of higher concentration of pendimethalin residue (0.292 µg/g) till the tenth day of crop age and consequently had the reduced yield (12.59 q/ha) than the dose of 0.7 kg/ha (13.33 q/ha) where plant mortality was only 12.62% due to comparatively lower level of pendimethalin residue (0.192 µg/g). Although the application of pendimethalin at the rate of 1.0 kg/ha was able to control weed more efficiently (18.96/m2) than the dose of 0.7 kg/ha (30.41/m2) and subsequent lower doses. The herbicide leached down to the root zone resulting in phytotoxicity towards crop. Yellow sarson group (Brassica campestris) showed more susceptibility than rai (Brassica juncea) group against pendimethalin application at higher doses. PMID:21217862

  14. Leaching behaviour of pendimethalin causes toxicity towards different cultivars of Brassica juncea and Brassica campestris in sandy loam soil.

    PubMed

    Bandyopadhyay, Subhendu; Choudhury, Partha P

    2009-12-01

    An experiment was conducted at the farm of Zonal Adaptive Research Station, Uttar Banga Krishi Viswavidhyalaya, Pundibari, Cooch Behar, West Bengal to evaluate the effect of pendimethalin on the yield, weed density and phytotoxicity in different varieties of rai (Brassica juncea) and yellow sarson (B. campestris var. yellow sarson) under higher soil moisture regime in Terai region of West Bengal. Pre-emergence application of pendimethalin at higher dose i.e. 1.0 kg/ha recorded higher plant mortality (30.92%) due to the presence of higher concentration of pendimethalin residue (0.292 µg/g) till the tenth day of crop age and consequently had the reduced yield (12.59 q/ha) than the dose of 0.7 kg/ha (13.33 q/ha) where plant mortality was only 12.62% due to comparatively lower level of pendimethalin residue (0.192 µg/g). Although the application of pendimethalin at the rate of 1.0 kg/ha was able to control weed more efficiently (18.96/m(2)) than the dose of 0.7 kg/ha (30.41/m(2)) and subsequent lower doses. The herbicide leached down to the root zone resulting in phytotoxicity towards crop. Yellow sarson group (Brassica campestris) showed more susceptibility than rai (Brassica juncea) group against pendimethalin application at higher doses. PMID:21217862

  15. Activity and species composition of aerobic methanotrophic communities in tundra soils.

    PubMed

    Vecherskaya, M S; Galchenko, V F; Sokolova, E N; Samarkin, V A

    1993-09-01

    The low-temperature, methane-oxidizing activities and species composition of methanotrophic communities in various tundra bog soils were investigated by radioisotopic and immunofluorescent methods. Methanotrophic bacteria carried out the methane oxidation process through all horizons of seasonally thawed layers down to permafrost. The highest activity of the process has been observed in the water surface layer of overmoistured soils and in water-logged moss covers. Up to 40% of(14)CH4 added was converted into(14)CO2, bacterial biomass, and organic exometabolites. By immunofluoresecent analysis it was demonstrated that the representatives of I+X (Methylomonas, Methylobacter, andMethylococcus) and II (Methylosinus, Methylocystis) methanotrophic groups occurred simultaneously in all samples at 61.6% and 38.4%, respectively. The number of methane-oxidizing bacteria in the ecosystems studied was 0.1-22.9×10(6) cells per gram of soil. Methanotrophic organisms ranged from 1% to 23% of the total bacterial number. PMID:23835752

  16. Characteristics of the soil-like substrates produced with a novel technique combining aerobic fermentation and earthworm treatment

    NASA Astrophysics Data System (ADS)

    Kang, Wenli; He, Wenting; Li, Leyuan; Liu, Hong

    2012-12-01

    The soil-like substrate (SLS) technique is key for improving the closure of bioregenerative life support system (BLSS) by recycling the inedible biomass of higher plants. In this study, a novel SLS technique (NSLST) was proposed: aerobic fermentations at 35 °C for 1 day, then 60 °C for 6 days, finally 30 °C for 3 days, followed by earthworm treatment for 70 days. Comparing with the original SLS technique (OSLST), its process cycle was 13 days shorter, and the dry weight loss rate (81.1%) was improved by 24.77%. The cellulose and lignin degradation rates were 96.6% and 94.6%. The concentrations of available N, P and K in mature SLS were respectively 776.1 mg/L, 348.0 mg/L and 7943.0 mg/L. Low CH4 and NH3 production was observed, but no accumulation. According to the seed germination test, the SLSs were feasible for plant growth. This investigation will provide a preliminary foundation for BLSS design.

  17. Humitalea rosea gen. nov., sp. nov., an aerobic bacteriochlorophyll-containing bacterium of the family Acetobacteraceae isolated from soil.

    PubMed

    Margesin, Rosa; Zhang, De-Chao

    2013-04-01

    A Gram-staining-negative, pale-pink-pigmented, non-motile, obligately aerobic and rod-shaped bacterium, designated strain W37(T), was isolated from soil and subjected to a taxonomic investigation using a polyphasic approach. The strain grew at 1-30 °C, oxidized thiosulfate and accumulated polyhydroxyalkanoates. Photosynthetic pigments were represented by bacteriochlorophyll a and carotenoids. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain W37(T) was most closely related to members of the genera Roseococcus and Rubritepida (with sequence similarities of <92.8 %) but formed a distinct lineage in the family Acetobacteraceae. The polar lipid profile comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, phosphatidylcholine, three unidentified aminolipids and one other unidentified lipid. The predominant cellular fatty acids were C18 : 1ω7c and summed feature 3 (C16 : 1ω7c and/or iso-C15 : 0 2-OH). The DNA G+C content of strain W37(T) was 68.2 mol%. On the basis of phenotypic characteristics and phylogenetic analysis, strain W37(T) represents a novel species of a new genus in the family Acetobacteraceae, for which the name Humitalea rosea gen. nov., sp. nov. is proposed. The type strain of the type species is W37(T) ( = CIP 110261(T) = LMG 26243(T)).

  18. COMPARISON OF GEOPROBE PRT AND AMS GVP SOIL-GAS SAMPLING SYSTEMS WITH DEDICATED VAPOR PROBES IN SANDY SOILS AT THE RAYMARK SUPERFUND SITE

    EPA Science Inventory

    A study was conducted near the Raymark Superfund Site in Stratford, Connecticut to compare results of soil-gas sampling using dedicated vapor probes, a truck-mounted direct-push technique - the Geoprobe Post-Run-Tubing (PRT) system, and a hand-held rotary hammer technique - the A...

  19. Comment on: ``Influence of inter-granular void ratio on monotonic and cyclic undrained shear response of sandy soils'' by M. Belkhatir, A. Arab, H. Missoum, T. Schanz [C. R. Mecanique 338 (2010) 290-303

    NASA Astrophysics Data System (ADS)

    Rahman, Md. Mizanur

    2011-01-01

    The authors should be commended for their interesting experimental work on sandy soils presented in Belkhatir et al. (2010) [1]. They used the inter-granular void ratio, e, to interpret the experimental results and developed some useful correlations with e. However, the Note fails to address the further development of e over a decade to a more generalized form of equivalent granular void ratio, e. This comment aims at adding missing literature on e and presents a re-interpretation of the experimental data based on e. The advantages of using e over e are significant and explained in subsequent sections.

  20. Degradation of polycyclic aromatic hydrocarbons at low temperature under aerobic and nitrate-reducing conditions in enrichment cultures from northern soils.

    PubMed

    Eriksson, Mikael; Sodersten, Erik; Yu, Zhongtang; Dalhammar, Gunnel; Mohn, William W

    2003-01-01

    The potential for biodegradation of polycyclic aromatic hydrocarbons (PAHs)at low temperature and under anaerobic conditions is not well understood, but such biodegradation would be very useful for remediation of polluted sites. Biodegradation of a mixture of 11 different PAHs with two to five aromatic rings, each at a concentration of 10 micro g/ml, was studied in enrichment cultures inoculated with samples of four northern soils. Under aerobic conditions, low temperature severely limited PAH biodegradation. After 90 days, aerobic cultures at 20 degrees C removed 52 to 88% of the PAHs. The most extensive PAH degradation under aerobic conditions at 7 degrees C,53% removal, occurred in a culture from creosote-contaminated soil. Low temperature did not substantially limit PAH biodegradation under nitrate-reducing conditions. Under nitrate-reducing conditions,naphthalene, 2-methylnaphthalene, fluorene, and phenanthrene were degraded. The most extensive PAH degradation under nitrate-reducing conditions at 7 degrees C, 39% removal, occurred in a culture from fuel-contaminated Arctic soil. In separate transfer cultures from the above Arctic soil, incubated anaerobically at 7 degrees C, removal of 2-methylnaphthalene and fluorene was stoichiometrically coupled to nitrate removal. Ribosomal intergenic spacer analysis suggested that enrichment resulted in a few predominant bacterial populations,including members of the genera Acidovorax,Bordetella, Pseudomonas, Sphingomonas, and Variovorax. Predominant populations from different soils often included phylotypes with nearly identical partial 16S rRNA gene sequences (i.e., same genus) but never included phylotypes with identical ribosomal intergenic spacers (i.e., different species or subspecies). The composition of the enriched communities appeared to be more affected by presence of oxygen, than by temperature or source of the inoculum. PMID:12514005

  1. Degradation of Polycyclic Aromatic Hydrocarbons at Low Temperature under Aerobic and Nitrate-Reducing Conditions in Enrichment Cultures from Northern Soils

    PubMed Central

    Eriksson, Mikael; Sodersten, Erik; Yu, Zhongtang; Dalhammar, Gunnel; Mohn, William W.

    2003-01-01

    The potential for biodegradation of polycyclic aromatic hydrocarbons (PAHs) at low temperature and under anaerobic conditions is not well understood, but such biodegradation would be very useful for remediation of polluted sites. Biodegradation of a mixture of 11 different PAHs with two to five aromatic rings, each at a concentration of 10 μg/ml, was studied in enrichment cultures inoculated with samples of four northern soils. Under aerobic conditions, low temperature severely limited PAH biodegradation. After 90 days, aerobic cultures at 20°C removed 52 to 88% of the PAHs. The most extensive PAH degradation under aerobic conditions at 7°C, 53% removal, occurred in a culture from creosote-contaminated soil. Low temperature did not substantially limit PAH biodegradation under nitrate-reducing conditions. Under nitrate-reducing conditions, naphthalene, 2-methylnaphthalene, fluorene, and phenanthrene were degraded. The most extensive PAH degradation under nitrate-reducing conditions at 7°C, 39% removal, occurred in a culture from fuel-contaminated Arctic soil. In separate transfer cultures from the above Arctic soil, incubated anaerobically at 7°C, removal of 2-methylnaphthalene and fluorene was stoichiometrically coupled to nitrate removal. Ribosomal intergenic spacer analysis suggested that enrichment resulted in a few predominant bacterial populations, including members of the genera Acidovorax, Bordetella, Pseudomonas, Sphingomonas, and Variovorax. Predominant populations from different soils often included phylotypes with nearly identical partial 16S rRNA gene sequences (i.e., same genus) but never included phylotypes with identical ribosomal intergenic spacers (i.e., different species or subspecies). The composition of the enriched communities appeared to be more affected by presence of oxygen, than by temperature or source of the inoculum. PMID:12514005

  2. Aerobic biodegradation of 2,4,6-trinitrotoluene (TNT) by Bacillus cereus isolated from contaminated soil.

    PubMed

    Mercimek, H Aysun; Dincer, Sadık; Guzeldag, Gulcihan; Ozsavli, Aysenur; Matyar, Fatih

    2013-10-01

    In this study, biological degradation of 2,4,6-trinitrotoluene (TNT) which is very highly toxic environmentally and an explosive in nitroaromatic character was researched in minimal medium by Bacillus cereus isolated from North Atlantic Treaty Organization (NATO) TNT-contaminated soils. In contrast to most previous studies, the capability of this bacteria to transform in liquid medium containing TNT was investigated. During degradation, treatment of TNT was followed by high-performance liquid chromatography (HPLC) and achievement of degradation was calculated as percentage. At an initial concentration of 50 and 75 mg L(-1), TNT was degraded respectively 68 % and 77 % in 96 h. It transformed into 2,4-dinitrotoluene and 4-aminodinitrotoluene derivates, which could be detected as intermediate metabolites by using thin-layer chromatography and gas chromatography-mass spectrometry analyses. Release of nitrite and nitrate ions were searched by spectrophotometric analyses. Depending upon Meisenheimer complex, while nitrite production was observed, nitrate was detected in none of the cultures. Results of our study propose which environmental pollutant can be removed by using microorganisms that are indigenous to the contaminated site. PMID:23715804

  3. Aerobic biodegradation of 2,4,6-trinitrotoluene (TNT) by Bacillus cereus isolated from contaminated soil.

    PubMed

    Mercimek, H Aysun; Dincer, Sadık; Guzeldag, Gulcihan; Ozsavli, Aysenur; Matyar, Fatih

    2013-10-01

    In this study, biological degradation of 2,4,6-trinitrotoluene (TNT) which is very highly toxic environmentally and an explosive in nitroaromatic character was researched in minimal medium by Bacillus cereus isolated from North Atlantic Treaty Organization (NATO) TNT-contaminated soils. In contrast to most previous studies, the capability of this bacteria to transform in liquid medium containing TNT was investigated. During degradation, treatment of TNT was followed by high-performance liquid chromatography (HPLC) and achievement of degradation was calculated as percentage. At an initial concentration of 50 and 75 mg L(-1), TNT was degraded respectively 68 % and 77 % in 96 h. It transformed into 2,4-dinitrotoluene and 4-aminodinitrotoluene derivates, which could be detected as intermediate metabolites by using thin-layer chromatography and gas chromatography-mass spectrometry analyses. Release of nitrite and nitrate ions were searched by spectrophotometric analyses. Depending upon Meisenheimer complex, while nitrite production was observed, nitrate was detected in none of the cultures. Results of our study propose which environmental pollutant can be removed by using microorganisms that are indigenous to the contaminated site.

  4. Analyzing Hurricane Sandy

    NASA Astrophysics Data System (ADS)

    Convertino, Angelyn; Meyer, Stephan; Edwards, Becca

    2015-03-01

    Post-tropical Storm Sandy underwent extratropical transition shortly before making landfall in southern New Jersey October 29 2012. Data from this system was compared with data from Hurricane Ike (2008) which represents a classic hurricane with a clear eye wall and symmetry after landfall. Storm Sandy collided with a low pressure system coming in from the north as the hurricane made landfall on the US East coast. This contributed to Storm Sandy acting as a non-typical hurricane when it made landfall. Time histories of wind speed and wind direction were generated from data provided by Texas Tech's StickNet probes for both storms. The NOAA Weather and Climate program were used to generate radar loops of reflectivity during the landfall for both storms; these loops were compared with time histories for both Ike and Sandy to identify a relationship between time series data and storm-scale features identified on radar.

  5. The determination of the real nano-scale sizes of bacteria in chernozem during microbial succession by means of hatching of a soil in aerobic and anaerobic conditions

    NASA Astrophysics Data System (ADS)

    Gorbacheva, M.

    2012-04-01

    M.A. Gorbacheva,L.M. Polyanskaya The Faculty of Soil Science, Moscow State University, Leninskie Gory, GSP-1, Moscow,119991,Russia In recent years there's been particular attention paid to the smallest life's forms- bacteria which size can be measured in nanometer. These are the forms of bacteria with diameter of 5-200 nm. Theoretical calculations based on the content of the minimum number of DNA, enzyme, lipids in and ribosome in cells indicates impossibility of existence of a living cells within diameter less than 300 nm. It is theoretically possible for a living cell to exist within possible diameter of approximately 140 nm. Using a fluorescence microscope there's been indicated in a number of samples from lakes, rivers, soil, snow and rain water that 200 nm is the smallest diameter of a living cell. Supposingly, such a small size of bacteria in soil is determined by natural conditions which limit their development by nutritious substances and stress-factors. Rejuvenescence of nanobacteria under unfavourable natural conditions and stress-factors is studied in laboratory environment. The object of the current study has become the samples of typical arable chernozem of the Central Chernozem State Biosphere Reserve in Kursk. The detailed morphological description of the soil profile and its basic analytical characteristics are widely represented in scientific publications. The soil is characterized by a high carbon content which makes up 3,96% ,3,8% , and 2,9% for the upper layers of the A horizon, and 0,79% for the layer of the B horizon. A microbial succession was studied under aerobic and anaerobic conditions by means of experiments with microcosms in upper A horizons and B horizon of a chernozem. The final aim is to identify the cells size of bacteria in aerobic and anaerobic soil conditions in chernozem during the microbial succession, by dampening and application of chitin by means of «cascade filtration» method. The study of the microcosms is important for

  6. Microseisms from Superstorm Sandy

    NASA Astrophysics Data System (ADS)

    Sufri, Oner; Koper, Keith D.; Burlacu, Relu; de Foy, Benjamin

    2014-09-01

    We analyzed and visualized the microseisms generated by Superstorm Sandy as recorded by the Earthscope Transportable Array (TA) during late October through early November of 2012. We applied continuous, frequency-dependent polarization analysis to the data and were able to track the course of Sandy as it approached the Florida coastline and, later, the northeastern coast of the U.S. The energy level of Sandy was roughly comparable to the background microseism level generated by wave-wave interactions in the North Atlantic and North Pacific oceans. The maximum microseismic power and degree of polarization were observed across the TA when Sandy sharply changed its direction to the west-northwest (specifically, towards Long Island, New York) on October 29. The westward turn also briefly changed the dominant microseism period from 5 s to 8 s. We identified three other microseismic source regions during the 18 day observation period. In particular, peak-splitting in the double frequency band and the orientation of the 5 s and 8 s polarization vectors revealed two contemporaneous microseism sources, one in the North Atlantic and one in the Northeast Pacific, for the dates of November 3-4. Predictions of microseismic excitation based on ocean wave models showed consistency with the observed microseismic energy generated by Sandy and other storms.

  7. Intensification of the aerobic bioremediation of an actual site soil historically contaminated by polychlorinated biphenyls (PCBs) through bioaugmentation with a non acclimated, complex source of microorganisms

    PubMed Central

    Di Toro, Sara; Zanaroli, Giulio; Fava, Fabio

    2006-01-01

    Background The biotreatability of actual-site polychlorinated biphenyl (PCB)-contaminated soils is often limited by their poor content of autochthonous pollutant-degrading microorganisms. In such cases, inoculation might be the solution for a successful bioremediation. Some pure and mixed cultures of characterized PCB degrading bacteria have been tested to this purpose. However, several failures have been recorded mostly due to the inability of inoculated microbes to compete with autochthonous microflora and to face the toxicity and the scarcity of nutrients occurring in the contaminated biotope. Complex microbial systems, such as compost or sludge, normally consisting of a large variety of robust microorganisms and essential nutrients, would have better chances to succeed in colonizing degraded contaminated soils. However, such sources of microorganisms have been poorly applied in soil bioremediation and in particular in the biotreatment of soil with PCBs. Thus, in this study the effects of Enzyveba, i.e. a consortium of non-adapted microorganisms developed from composted material, on the slurry- and solid-phase aerobic bioremediation of an actual-site, aged PCB-contaminated soil were studied. Results A slow and only partial biodegradation of low-chlorinated biphenyls, along with a moderate depletion of initial soil ecotoxicity, were observed in the not-inoculated reactors. Enzyveba significantly increased the availability and the persistence of aerobic PCB- and chlorobenzoic acid-degrading cultivable bacteria in the bioreactors, in particular during the earlier phase of treatment. It also markedly enhanced PCB-biodegradation rate and extent (from 50 to 100%) as well as the final soil detoxification, in particular under slurry-phase conditions. Taken together, data obtained suggest that Enzyveba enhanced the biotreatability of the selected soil by providing exogenous bacteria and fungi able to remove inhibitory or toxic intermediates of PCB biodegradation and

  8. Reflections on Sandy Hook

    ERIC Educational Resources Information Center

    Trump, Kenneth S.

    2013-01-01

    In this article, the author shares his thoughts for district administrators regarding the Sandy Hook Elementary school tragedy. Administrators heard a lot of potential solutions or attempts at solutions. However, these proposals raise lengthy lists of implementation questions and issues that illustrate a lack of understanding of school operations,…

  9. Determination of the uptake of [Pt(NH3)4](NO3)2 by grass cultivated on a sandy loam soil and by cucumber plants, grown hydroponically.

    PubMed

    Verstraete, D; Riondato, J; Vercauteren, J; Vanhaecke, F; Moens, L; Dams, R; Verloo, M

    1998-07-30

    Two cultivation experiments were carried out in order to answer the question to what extent platinum can enter the food chain by accumulation in plants, when the platinum is present in a bio-available form: (i) cucumber plants (Cucumis sativus) were grown hydroponically in nutrient solutions containing [Pt(NH3)4](NO3)2 (from 0.5 to 50 micrograms Pt/l solution); and (ii) a water-soluble platinum compound--[Pt(NH3)4](NO3)2--was added in increasing amounts to a sandy loam soil (from 0.5 to 50 mg Pt/kg soil) and rye grass (Lolium perenne) was grown on it. The roots on the one hand and the green plant fractions in the other hand of the cucumber plants and the rye grass were digested using a high-pressure asher. The platinum concentration was determined by means of a quadrupole-based (VG PQ I) or a double focusing sector field ICP-mass spectrometer (Finnigan MAT, Element), depending on the platinum concentration in the sample solution. The detection limit for platinum obtained with the VG PQ I was observed to be 6 ng/1, while with the 'Element' the detection limit could be improved to 0.5 ng/1 Pt. Accumulation factors were calculated as the ratio of the platinum concentration in the plant to that in the soil or the nutrient solution. The grass grown on spiked soil accumulated platinum only to a slight degree (accumulation factors between 0.008 and 0.032). The hydroponically grown cucumber plants, however, strongly accumulated it (accumulation factors of 11-42 in the shoot and 1700-2100 in the roots). There are three possible causes for the large differences in the accumulation factors: (i) Cucumber plants are dicotyledons; grass, however, is a monocotyledon. Other cultivation experiments already showed that dicotyledons accumulate metals to a higher extent than monocotyledons. (ii) In the grass cultivation experiment, the platinum compound was only added once to the sandy loam soil, namely 2 days before grass was cultivated on it. The nutrient solutions of the cucumber

  10. Soil Physical Constraints on Intrinsic Biodegradation of Petroleum Vapors in a Layered Subsurface

    PubMed Central

    Kristensen, Andreas H.; Henriksen, Kaj; Mortensen, Lars; Scow, Kate M.; Moldrup, Per

    2011-01-01

    Naturally occurring biodegradation of petroleum hydrocarbons in the vadose zone depends on the physical soil environment influencing field-scale gas exchange and pore-scale microbial metabolism. In this study, we evaluated the effect of soil physical heterogeneity on biodegradation of petroleum vapors in a 16-m-deep, layered vadose zone. Soil slurry experiments (soil/water ratio 10:30 w/w, 25°C) on benzene biodegradation under aerobic and well-mixed conditions indicated that the biodegradation potential in different textured soil samples was related to soil type rather than depth, in the order: sandy loam > fine sand > limestone. Similarly, O2 consumption rates during in situ respiration tests performed at the site were higher in the sandy loam than in the fine sand, although the difference was less significant than in the slurries. Laboratory and field data generally agreed well and suggested a significant potential for aerobic biodegradation, even with nutrient-poor and deep subsurface conditions. In slurries of the sandy loam, the biodegradation potential declined with increasing in situ water saturation (i.e., decreasing air-filled porosity in the field). This showed a relation between antecedent undisturbed field conditions and the slurry biodegradation potential, and suggested airfilled porosity to be a key factor for the intrinsic biodegradation potential in the field. PMID:21617737

  11. Soil Physical Constraints on Intrinsic Biodegradation of Petroleum Vapors in a Layered Subsurface.

    PubMed

    Kristensen, Andreas H; Henriksen, Kaj; Mortensen, Lars; Scow, Kate M; Moldrup, Per

    2010-02-01

    Naturally occurring biodegradation of petroleum hydrocarbons in the vadose zone depends on the physical soil environment influencing field-scale gas exchange and pore-scale microbial metabolism. In this study, we evaluated the effect of soil physical heterogeneity on biodegradation of petroleum vapors in a 16-m-deep, layered vadose zone. Soil slurry experiments (soil/water ratio 10:30 w/w, 25°C) on benzene biodegradation under aerobic and well-mixed conditions indicated that the biodegradation potential in different textured soil samples was related to soil type rather than depth, in the order: sandy loam > fine sand > limestone. Similarly, O(2) consumption rates during in situ respiration tests performed at the site were higher in the sandy loam than in the fine sand, although the difference was less significant than in the slurries. Laboratory and field data generally agreed well and suggested a significant potential for aerobic biodegradation, even with nutrient-poor and deep subsurface conditions. In slurries of the sandy loam, the biodegradation potential declined with increasing in situ water saturation (i.e., decreasing air-filled porosity in the field). This showed a relation between antecedent undisturbed field conditions and the slurry biodegradation potential, and suggested airfilled porosity to be a key factor for the intrinsic biodegradation potential in the field. PMID:21617737

  12. Spatial Heterogeneity of Soil Nutrients after the Establishment of Caragana intermedia Plantation on Sand Dunes in Alpine Sandy Land of the Tibet Plateau

    PubMed Central

    Li, Qingxue; Jia, Zhiqing; Zhu, Yajuan; Wang, Yongsheng; Li, Hong; Yang, Defu; Zhao, Xuebin

    2015-01-01

    The Gonghe Basin region of the Tibet Plateau is severely affected by desertification. Compared with other desertified land, the main features of this region is windy, cold and short growing season, resulting in relatively difficult for vegetation restoration. In this harsh environment, identification the spatial distribution of soil nutrients and analysis its impact factors after vegetation establishment will be helpful for understanding the ecological relationship between soil and environment. Therefore, in this study, the 12-year-old C. intermedia plantation on sand dunes was selected as the experimental site. Soil samples were collected under and between shrubs on the windward slopes, dune tops and leeward slopes with different soil depth. Then analyzed soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP) and available potassium (AK). The results showed that the spatial heterogeneity of soil nutrients was existed in C. intermedia plantation on sand dunes. (1) Depth was the most important impact factor, soil nutrients were decreased with greater soil depth. One of the possible reasons is that windblown fine materials and litters were accumulated on surface soil, when they were decomposed, more nutrients were aggregated on surface soil. (2) Topography also affected the distribution of soil nutrients, more soil nutrients distributed on windward slopes. The herbaceous coverage were higher and C. intermedia ground diameter were larger on windward slopes, both of them probably related to the high soil nutrients level for windward slopes. (3) Soil “fertile islands” were formed, and the “fertile islands” were more marked on lower soil nutrients level topography positions, while it decreased towards higher soil nutrients level topography positions. The enrichment ratio (E) for TN and AN were higher than other nutrients, most likely because C. intermedia is a leguminous

  13. Spatial Heterogeneity of Soil Nutrients after the Establishment of Caragana intermedia Plantation on Sand Dunes in Alpine Sandy Land of the Tibet Plateau.

    PubMed

    Li, Qingxue; Jia, Zhiqing; Zhu, Yajuan; Wang, Yongsheng; Li, Hong; Yang, Defu; Zhao, Xuebin

    2015-01-01

    The Gonghe Basin region of the Tibet Plateau is severely affected by desertification. Compared with other desertified land, the main features of this region is windy, cold and short growing season, resulting in relatively difficult for vegetation restoration. In this harsh environment, identification the spatial distribution of soil nutrients and analysis its impact factors after vegetation establishment will be helpful for understanding the ecological relationship between soil and environment. Therefore, in this study, the 12-year-old C. intermedia plantation on sand dunes was selected as the experimental site. Soil samples were collected under and between shrubs on the windward slopes, dune tops and leeward slopes with different soil depth. Then analyzed soil organic matter (SOM), total nitrogen (TN), total phosphorus (TP), total potassium (TK), available nitrogen (AN), available phosphorus (AP) and available potassium (AK). The results showed that the spatial heterogeneity of soil nutrients was existed in C. intermedia plantation on sand dunes. (1) Depth was the most important impact factor, soil nutrients were decreased with greater soil depth. One of the possible reasons is that windblown fine materials and litters were accumulated on surface soil, when they were decomposed, more nutrients were aggregated on surface soil. (2) Topography also affected the distribution of soil nutrients, more soil nutrients distributed on windward slopes. The herbaceous coverage were higher and C. intermedia ground diameter were larger on windward slopes, both of them probably related to the high soil nutrients level for windward slopes. (3) Soil "fertile islands" were formed, and the "fertile islands" were more marked on lower soil nutrients level topography positions, while it decreased towards higher soil nutrients level topography positions. The enrichment ratio (E) for TN and AN were higher than other nutrients, most likely because C. intermedia is a leguminous shrub.

  14. Aerobic biodegradation of toluene-2,4-di(8:2 fluorotelomer urethane) and hexamethylene-1,6-di(8:2 fluorotelomer urethane) monomers in soils.

    PubMed

    Dasu, Kavitha; Lee, Linda S

    2016-02-01

    Aerobic soil biodegradation of toluene-2,4-di(8:2 fluorotelomer urethane) (FTU) and hexamethylene-1,6-di(8:2 fluorotelomer urethane) (HMU) in a forest soil and FTU in an agricultural silty clay loam soil was monitored for up to 6 months. Fluorotelomer alcohols were measured in headspace and parent monomers and all metabolites in soil extracts. Negligible degradation of FTU biodegradation occurred in the agricultural soil with 94 ± 15% recovered at day 180. However, in the forest soil, both FTU and HMU degradation was evident with significant losses of 24% (117 d) and 27% (180 day), respectively, and concomitant increases in the terminal metabolite, perfluorooctanoic acid (PFOA) concentrations were well above what could result from residual 8:2 FTOH. Kinetic modeling estimated half-lives for FTU (aromatic backbone) and HMU (aliphatic backbone) in the forest soil to be 3-5 months and 15.9-22.2 months, respectively. The addition of a structurally similar non-fluorinated FTU analog, toluene-2,4-dicarbamic acid diethyl ester (TDAEE) enhanced production of terminal end products from 8:2 FTOH degradation. However, there was no clear evidence that TDAEE enhanced cleavage of the urethane bond, thus TDAEE appeared to just serve as an additional carbon source. TDAEE's half-life was ∼ one week. A second addition of TDAEE appeared to retard subsequent degradation of FTU exemplifying the microbial dynamics and diversity impacting degradation of polyfluoroalkyl substances. Enhanced degradation of HMU was observed upon re-aeration indicating oxygen may have been limiting during some periods although degradation of intermediate metabolites to terminal metabolites was still occurring, albeit at slower rates.

  15. Aerobic biodegradation of toluene-2,4-di(8:2 fluorotelomer urethane) and hexamethylene-1,6-di(8:2 fluorotelomer urethane) monomers in soils.

    PubMed

    Dasu, Kavitha; Lee, Linda S

    2016-02-01

    Aerobic soil biodegradation of toluene-2,4-di(8:2 fluorotelomer urethane) (FTU) and hexamethylene-1,6-di(8:2 fluorotelomer urethane) (HMU) in a forest soil and FTU in an agricultural silty clay loam soil was monitored for up to 6 months. Fluorotelomer alcohols were measured in headspace and parent monomers and all metabolites in soil extracts. Negligible degradation of FTU biodegradation occurred in the agricultural soil with 94 ± 15% recovered at day 180. However, in the forest soil, both FTU and HMU degradation was evident with significant losses of 24% (117 d) and 27% (180 day), respectively, and concomitant increases in the terminal metabolite, perfluorooctanoic acid (PFOA) concentrations were well above what could result from residual 8:2 FTOH. Kinetic modeling estimated half-lives for FTU (aromatic backbone) and HMU (aliphatic backbone) in the forest soil to be 3-5 months and 15.9-22.2 months, respectively. The addition of a structurally similar non-fluorinated FTU analog, toluene-2,4-dicarbamic acid diethyl ester (TDAEE) enhanced production of terminal end products from 8:2 FTOH degradation. However, there was no clear evidence that TDAEE enhanced cleavage of the urethane bond, thus TDAEE appeared to just serve as an additional carbon source. TDAEE's half-life was ∼ one week. A second addition of TDAEE appeared to retard subsequent degradation of FTU exemplifying the microbial dynamics and diversity impacting degradation of polyfluoroalkyl substances. Enhanced degradation of HMU was observed upon re-aeration indicating oxygen may have been limiting during some periods although degradation of intermediate metabolites to terminal metabolites was still occurring, albeit at slower rates. PMID:26624955

  16. Simulating the effect of aerobic biodegradation on soil vapor intrusion into buildings: influence of degradation rate, source concentration, and depth.

    PubMed

    Abreu, Lilian D V; Johnson, Paul C

    2006-04-01

    Steady-state vapor intrusion scenarios involving aerobically biodegradable chemicals are studied using a three-dimensional multicomponent numerical model. In these scenarios, sources of aerobically biodegradable chemical vapors are placed at depths of 1-14 m beneath a 10 m x 10 m basement or slab-on-grade construction building, and the simultaneous transport and reaction of hydrocarbon and oxygen vapors are simulated. The results are presented as Johnson and Ettinger attenuation factors alpha (predicted indoor air hydrocarbon concentration/source vapor concentration), and normalized contour plots of hydrocarbon and oxygen concentrations. In addition to varying the vapor source depth, the effects of source concentration (2-200 mg chemical/L vapor) and oxygen-limited first-order reaction rates (0.018-1.8 h(-1)) are studied. Hydrocarbon inputs were specific to benzene, although the relevant properties are similar to those for a range of hydrocarbons of interest. Overall, the results suggest that aerobic biodegradation could play a significant role in reducing vapor intrusion into buildings (decreased alpha-values) relative to the no-biodegradation case, with the significance of aerobic biodegradation increasing with increasing vapor source depth, decreasing vapor source concentration, and increasing first-order biodegradation rate. In contrast to the no-biodegradation case, differences in foundation construction can be significant in some settings. The significance of aerobic biodegradation is directly related to the extent to which oxygen is capable of migrating beneath the foundation. For example, in the case of a basement scenario with a 200 mg/L vapor source located at 3 m bgs, oxygen is consumed before it can migrate beneath the foundation, so the attenuation factors for simulations with and without aerobic biodegradation are similar for all first-order rates studied. For the case of a 2 mg/L vapor source located at 8 m bgs, the oxygen is widely distributed

  17. The effect of the potential fuel additive isobutanol on benzene, toluene, ethylbenzene, and p-xylene degradation in aerobic soil microcosms.

    PubMed

    Ding, Liang; Cupples, Alison M

    2015-01-01

    Isobutanol is being considered as a fuel additive; however, the effect of this chemical on gasoline degradation (following a spill) has yet to be fully explored. To address this, the current study investigated the effect of isobutanol on benzene, toluene, ethylbenzene and p-xylene (BTEX) degradation in 14 sets of experiments in saturated soils. This involved four hydrocarbons for three soils (12 experiments) and two extra experiments with a lower level of isobutanol (for toluene only). Each soil and hydrocarbon combination involved four abiotic control microcosms and 12 sample microcosms (six with and six without isobutanol). The time for complete degradation of each hydrocarbon varied between treatments. Both toluene and ethylbenzene were rapidly degraded (5-13 days for toluene and 3-13 days for ethylbenzene). In contrast, the time for complete degradation for benzene ranged from 5 to 47 days. The hydrocarbon p-xylene was the most recalcitrant chemical (time for removal ranged from 14 to 86 days) and, in several microcosms, no p-xylene degradation was observed. The effect of isobutanol on hydrocarbon degradation was determined by comparing degradation lag times with and without isobutanol addition. From the 14 treatments, isobutanol only affected degradation lag times in three cases. In two cases (benzene and p-xylene), an enhancement of degradation (reduced lag times) was observed in the presence of isobutanol. In contrast, toluene degradation in one soil was inhibited (increased lag time). These results indicate that co-contamination with isobutanol should not inhibit aerobic BTEX degradation rates.

  18. Aerobic degradation of a hydrocarbon mixture in natural uncontaminated potting soil by indigenous microorganisms at 20 degrees C and 6 degrees C.

    PubMed

    Eriksson, M; Dalhammar, G; Borg-Karlson, A K

    1999-04-01

    A hydrocarbon mixture containing p-xylene, naphthalene, Br-naphthalene and straight aliphatic hydrocarbons (C14 to C17) was aerobically degraded without lag phase by a natural uncontaminated potting soil at 20 degrees C and 6 degrees C. Starting concentrations were approximately 46 ppm for the aromatic and 13 ppm for the aliphatic compounds. All aliphatic hydrocarbons were degraded within 5 days at 20 degrees C, to levels below detection (ppb levels) but only down to 10% of initial concentration at 6 degrees C. Naphthalene was degraded within 12 days at 20 degrees C and unaffected at 6 degrees C. At 20 degrees C p-xylene was degraded within 20 days, but no degradation occurred at 6 degrees C. Br-naphthalene was only removed down to 30% of initial concentration at 20 degrees C, with no significant effect at 6 degrees C. The biodegradation was monitored with head space solid-phase microextraction and gas chromatography-mass spectrometry.

  19. Quantitative assessment of the toxic effects of heavy metals on 1,2-dichloroethane biodegradation in co-contaminated soil under aerobic condition.

    PubMed

    Olaniran, Ademola Olufolahan; Balgobind, Adhika; Pillay, Balakrishna

    2011-10-01

    1,2-Dichloroethane (1,2-DCA) is one of the most hazardous pollutant of soil and groundwater, and is produced in excess of 5.44×10⁹ kg annually. Owing to their toxicity, persistence and potential for bioaccumulation, there is a growing interest in technologies for their removal. Heavy metals are known to be toxic to soil microorganisms at high concentrations and can hinder the biodegradation of organic contaminants. In this study, the inhibitory effect of heavy metals, namely; arsenic, cadmium, mercury and lead, on the aerobic biodegradation of 1,2-DCA by autochthonous microorganisms was evaluated in soil microcosm setting. The presence of heavy metals was observed to have a negative impact on the biodegradation of 1,2-DCA in both soil samples tested, with the toxic effect being more pronounced in loam soil, than in clay soil. Generally, 75 ppm As³⁺, 840 ppm Hg²⁺, and 420 ppm Pb²⁺ resulted in 34.24%, 40.64%, and 45.94% increase in the half live (t½) of 1,2-DCA, respectively, in loam soil, while concentrations above 127.5 ppm Cd²⁺, 840 ppm Hg²⁺ and 420 ppm of Pb²⁺ and less than 75 ppm As³⁺ was required to cause a >10% increase in the t½ of 1,2-DCA in clay soil. A dose-dependent relationship between degradation rate constant (k₁) of 1,2-DCA and metal ion concentrations was observed for all the heavy metals tested, except for Hg²⁺. This study demonstrated that different heavy metals have different impacts on the degree of 1,2-DCA degradation. Results also suggest that the degree of inhibition is metal specific and is also dependent on several factors including; soil type, pH, moisture content and available nutrients.

  20. Engineered biochar from microwave-assisted catalytic pyrolysis of switchgrass for increasing water-holding capacity and fertility of sandy soil.

    PubMed

    Mohamed, Badr A; Ellis, Naoko; Kim, Chang Soo; Bi, Xiaotao; Emam, Ahmed El-Raie

    2016-10-01

    Engineered biochars produced from microwave-assisted catalytic pyrolysis of switchgrass have been evaluated in terms of their ability on improving water holding capacity (WHC), cation exchange capacity (CEC) and fertility of loamy sand soil. The addition of K3PO4, clinoptilolite and/or bentonite as catalysts during the pyrolysis process increased biochar surface area and plant nutrient contents. Adding biochar produced with 10wt.% K3PO4+10 wt.% clinoptilolite as catalysts to the soil at 2wt% load increased soil WHC by 98% and 57% compared to the treatments without biochar (control) and with 10wt.% clinoptilolite, respectively. Synergistic effects on increased soil WHC were manifested for biochars produced from combinations of two additives compared to single additive, which may be the result of increased biochar microporosity due to increased microwave heating rate. Biochar produced from microwave catalytic pyrolysis was more efficient in increasing the soil WHC due to its high porosity in comparison with the biochar produced from conventional pyrolysis at the same conditions. The increases in soil CEC varied widely compared to the control soil, ranging from 17 to 220% for the treatments with biochars produced with 10wt% clinoptilolite at 400°C, and 30wt% K3PO4 at 300°C, respectively. Strong positive correlations also exist among soil WHC with CEC and biochar micropore area. Biochar from microwave-assisted catalytic pyrolysis appears to be a novel approach for producing biochar with high sorption affinity and high CEC. These catalysts remaining in the biochar product would provide essential nutrients for the growth of bioenergy and food crops.

  1. Community structure of ammonia-oxidizing bacteria under long-term application of mineral fertilizer and organic manure in a sandy loam soil.

    PubMed

    Chu, Haiyan; Fujii, Takeshi; Morimoto, Sho; Lin, Xiangui; Yagi, Kazuyuki; Hu, Junli; Zhang, Jiabao

    2007-01-01

    The effects of mineral fertilizer (NPK) and organic manure on the community structure of soil ammonia-oxidizing bacteria (AOB) was investigated in a long-term (16-year) fertilizer experiment. The experiment included seven treatments: organic manure, half organic manure N plus half fertilizer N, fertilizer NPK, fertilizer NP, fertilizer NK, fertilizer PK, and the control (without fertilization). N fertilization greatly increased soil nitrification potential, and mineral N fertilizer had a greater impact than organic manure, while N deficiency treatment (PK) had no significant effect. AOB community structure was analyzed by PCR-denaturing gradient gel electrophoresis (PCR-DGGE) of the amoA gene, which encodes the alpha subunit of ammonia monooxygenase. DGGE profiles showed that the AOB community was more diverse in N-fertilized treatments than in the PK-fertilized treatment or the control, while one dominant band observed in the control could not be detected in any of the fertilized treatments. Phylogenetic analysis showed that the DGGE bands derived from N-fertilized treatments belonged to Nitrosospira cluster 3, indicating that N fertilization resulted in the dominance of Nitrosospira cluster 3 in soil. These results demonstrate that long-term application of N fertilizers could result in increased soil nitrification potential and the AOB community shifts in soil. Our results also showed the different effects of mineral fertilizer N versus organic manure N; the effects of P and K on the soil AOB community; and the importance of balanced fertilization with N, P, and K in promoting nitrification functions in arable soils. PMID:17098920

  2. Paleosols can promote root growth of the recent vegetation - a case study from the sandy soil-sediment sequence Rakt, the Netherlands

    NASA Astrophysics Data System (ADS)

    Gocke, M. I.; Kessler, F.; van Mourik, J. M.; Jansen, B.; Wiesenberg, G. L. B.

    2015-12-01

    Soil studies commonly comprise the uppermost meter for tracing e.g. soil development. However, the maximum rooting depth of various plants significantly exceeds this depth. We hypothesized that deeper parts of the soil, soil parent material and especially paleosols provide beneficial conditions in terms of e.g. nutrient contents, thus supporting their utilization and exploitation by deep roots. We aimed to decipher the different phases of soil formation in Dutch drift- and coversands. The study site is located at Bedafse Bergen (SE Netherlands) in a 200 year old oak stand. A recent Podzol developed on driftsand covering a Plaggic Anthrosol that established in a relict Podzol on Late Glacial eolian coversand. Root-free soil and sediment samples, collected in 10-15 cm depth increments, were subjected to a multi-proxy physical and geochemical approach. The Plaggic Anthrosol revealed low bulk density and high phosphorous and organic carbon contents, whereas the relict Podzol was characterized by high iron and aluminum contents. Frequencies of fine (≤ 2 mm) and medium roots (2-5 mm) were determined on horizontal levels and the profile wall for a detailed pseudo-three-dimensional insight. On horizontal levels, living roots maximized in the uppermost part of the relict Podzol with ca. 4450 and 220 m-2, significantly exceeding topsoil root abundances. Roots of oak trees thus benefited from the favorable growth conditions in the nutrient-rich Plaggic Anthrosol, whereas increased compactness and high aluminum contents of the relict Podzol caused a strong decrease of roots. The approach demonstrated the benefit of comprehensive root investigation to support and explain pedogenic investigations of soil profiles, as fine roots can be significantly underestimated when quantified at the profile wall. The possible rooting of soil parent material and paleosols long after their burial confirmed recent studies on the potential influence of rooting to overprint sediment-(paleo)soil

  3. Detecting a salinity plume in an unconfined sandy aquifer and assessing secondary soil salinization using electromagnetic induction techniques, North Dakota, USA

    NASA Astrophysics Data System (ADS)

    Hopkins, D. G.; Richardson, J. L.

    1999-08-01

    Land-use changes on the Sheyenne Delta in southeastern North Dakota, USA, have prompted research on impacts to the unconfined Sheyenne Delta aquifer (SDA). This study examines effects of the saline discharge of a flowing artesian well that taps the Dakota aquifer (DAK) on SDA groundwater chemistry and soil salinity. Objectives were to map the saline plume in the SDA using induction techniques, to assess chloride migration in the SDA, and to evaluate induction sensitivity to moderately saline sands. Induction data, collected in a 2.9-ha grid, were compared to 31 soil profiles analyzed for gravimetric moisture, electrical conductivity, and chloride. Soil salinization is widespread, but only 7% of the area meets the 4-dS/m threshold for saline soils. SDA chloride distribution was determined on transects oriented with and perpendicular to the flow path determined from induction readings. Chloride was detected in the aquifer 550 m from the source, indicating a transport rate of 21 m/yr. Complex recharge and discharge patterns and hummocky relief contribute to a wide chloride plume at this site. A mass balance based on soil-water content and chloride concentration shows that only 4% of the chloride from the DAK well remains in the grid volume.

  4. Arbuscular mycorrhizal fungus enhances P acquisition of wheat (Triticum aestivum L.) in a sandy loam soil with long-term inorganic fertilization regime.

    PubMed

    Hu, Junli; Lin, Xiangui; Wang, Junhua; Cui, Xiangchao; Dai, Jue; Chu, Haiyan; Zhang, Jiabao

    2010-10-01

    The P efficiency, crop yield, and response of wheat to arbuscular mycorrhizal fungus (AMF) Glomus caledonium were tested in an experimental field with long-term (19 years) fertilizer management. The experiment included five fertilizer treatments: organic amendment (OA), half organic amendment plus half mineral fertilizer (1/2 OM), mineral fertilizer NPK, mineral fertilizer NK, and the control (without fertilization). AMF inoculation responsiveness (MIR) of wheat plants at acquiring P were estimated by comparing plants grown in unsterilized soil inoculated with G. caledonium and in untreated soil containing indigenous AMF. Without AMF inoculation, higher crop yields but lower colonization rates were observed in the NPK and two OA-inputted treatments, and NPK had significantly (P < 0.05) lower impacts on organic C and available P in soils and thereby P acquisition of wheat plants compared with OA and 1/2 OM. G. caledonium inoculation significantly (P < 0.05) increased colonization rates with the NPK and two P-deficient treatments but significantly (P < 0.05) increased vegetative biomass, crop yield, and P acquisition of wheat as well as soil alkaline phosphatase (ALP) activity, only with the NPK treatment. This gave an MIR of ca. 45% on total P acquisition of wheat plants. There were no other remarkable MIRs. It suggested that the MIR is determined by soil available P status, and rational combination of AMF with chemical NPK fertilizer can compensate for organic amendments by improving P-acquisition efficiency in arable soils.

  5. Nitrososphaera viennensis gen. nov., sp. nov., an aerobic and mesophilic, ammonia-oxidizing archaeon from soil and a member of the archaeal phylum Thaumarchaeota

    PubMed Central

    Stieglmeier, Michaela; Klingl, Andreas; Alves, Ricardo J. E.; Rittmann, Simon K.-M. R.; Melcher, Michael; Leisch, Nikolaus

    2014-01-01

    A mesophilic, neutrophilic and aerobic, ammonia-oxidizing archaeon, strain EN76T, was isolated from garden soil in Vienna (Austria). Cells were irregular cocci with a diameter of 0.6–0.9 µm and possessed archaella and archaeal pili as cell appendages. Electron microscopy also indicated clearly discernible areas of high and low electron density, as well as tubule-like structures. Strain EN76T had an S-layer with p3 symmetry, so far only reported for members of the Sulfolobales. Crenarchaeol was the major core lipid. The organism gained energy by oxidizing ammonia to nitrite aerobically, thereby fixing CO2, but growth depended on the addition of small amounts of organic acids. The optimal growth temperature was 42 °C and the optimal pH was 7.5, with ammonium and pyruvate concentrations of 2.6 and 1 mM, respectively. The genome of strain EN76T had a DNA G+C content of 52.7 mol%. Phylogenetic analyses of 16S rRNA genes showed that strain EN76T is affiliated with the recently proposed phylum Thaumarchaeota, sharing 85 % 16S rRNA gene sequence identity with the closest cultivated relative ‘Candidatus Nitrosopumilus maritimus’ SCM1, a marine ammonia-oxidizing archaeon, and a maximum of 81 % 16S rRNA gene sequence identity with members of the phyla Crenarchaeota and Euryarchaeota and any of the other recently proposed phyla (e.g. ‘Korarchaeota’ and ‘Aigarchaeota’). We propose the name Nitrososphaera viennensis gen. nov., sp. nov. to accommodate strain EN76T. The type strain of Nitrososphaera viennensis is strain EN76T ( = DSM 26422T = JMC 19564T). Additionally, we propose the family Nitrososphaeraceae fam. nov., the order Nitrososphaerales ord. nov. and the class Nitrososphaeria classis nov. PMID:24907263

  6. Seasonal rainfall partitioning under runon and runoff conditions on sandy soil in Niger. On-farm measurements and water balance modelling

    NASA Astrophysics Data System (ADS)

    Rockström, J.; Jansson, P.-E.; Barron, J.

    1998-09-01

    In sparsely cropped farming systems in semi-arid tropics, rainfall partitioning can be complex due to various interactions between vertical and horizontal water flows, both in the atmosphere and in the soil. Despite this, quantifying the seasonal rainfall partitioning is essential, in order to identify options for increased yields. Results are presented on water flow components, based on field measurements and water balance modelling, for three years (1994-96) in a farmer's field cultivated with pearl millet [ Pennisetum glaucum (L.) Br.] in the Sahel (Niger). Water balance modelling was carried out for three common infiltration categories: runoff producing surfaces, surfaces receiving inflow of runon water from upstream zones, and a reference surface with zero runoff and runon. Runoff was calculated to 25%-30% of annual rainfall (which ranged from 488 to 596 mm), from crust observations, rainfall, soil wetness data, and infiltration estimates. Inflow of runon was estimated from field observations to 8%-18% of annual rainfall. The parameters in the functions for soil surface and canopy resistances were calibrated with field measurements of soil evaporation, stomatal conductance and leaf area. The model estimates of soil water contents, which were validated against neutron probe measurements, showed a reasonable agreement with observed data, with a root mean square error (RMSE) of approximately 0.02 m 3 m -3 for 0-160 cmsoil depth. Estimated productive water flow as plant transpiration was low, amounting to 4%-9% of the available water for the non-fertilised crop and 7%-24% for the fertilised crop. Soil evaporation accounted for 31%-50% of the available water, and showed a low variation for the observed range of leaf area (LAI <1m 2 m -2). Deep percolation was high, amounting to 200-330 mm for the non-crusted surfaces, which exceeded soil evaporation losses, for 1994-95 with relatively high annual rainfall (517-596 mm). Even a year with lower rainfall (488 mm) and a

  7. Feasibility of electrokinetic oxygen supply for soil bioremediation purposes.

    PubMed

    Mena Ramírez, E; Villaseñor Camacho, J; Rodrigo Rodrigo, M A; Cañizares Cañizares, P

    2014-12-01

    This paper studies the possibility of providing oxygen to a soil by an electrokinetic technique, so that the method could be used in future aerobic polluted soil bioremediation treatments. The oxygen was generated from the anodic reaction of water electrolysis and transported to the soil in a laboratory-scale electrokinetic cell. Two variables were tested: the soil texture and the voltage gradient. The technique was tested in two artificial soils (clay and sand) and later in a real silty soil, and three voltage gradients were used: 0.0 (control), 0.5, and 1.0 V cm(-1). It was observed that these two variables strongly influenced the results. Oxygen transport into the soil was only available in the silty and sandy soils by oxygen diffusion, obtaining high dissolved oxygen concentrations, between 4 and 9 mg L(-1), useful for possible aerobic biodegradation processes, while transport was not possible in fine-grained soils such as clay. Electro-osmotic flow did not contribute to the transport of oxygen, and an increase in voltage gradients produced higher oxygen transfer rates. However, only a minimum fraction of the electrolytically generated oxygen was efficiently used, and the maximum oxygen transport rate observed, approximately 1.4 mgO2 L(-1)d(-1), was rather low, so this technique could be only tested in slow in-situ biostimulation processes for organics removal from polluted soils.

  8. Feasibility of electrokinetic oxygen supply for soil bioremediation purposes.

    PubMed

    Mena Ramírez, E; Villaseñor Camacho, J; Rodrigo Rodrigo, M A; Cañizares Cañizares, P

    2014-12-01

    This paper studies the possibility of providing oxygen to a soil by an electrokinetic technique, so that the method could be used in future aerobic polluted soil bioremediation treatments. The oxygen was generated from the anodic reaction of water electrolysis and transported to the soil in a laboratory-scale electrokinetic cell. Two variables were tested: the soil texture and the voltage gradient. The technique was tested in two artificial soils (clay and sand) and later in a real silty soil, and three voltage gradients were used: 0.0 (control), 0.5, and 1.0 V cm(-1). It was observed that these two variables strongly influenced the results. Oxygen transport into the soil was only available in the silty and sandy soils by oxygen diffusion, obtaining high dissolved oxygen concentrations, between 4 and 9 mg L(-1), useful for possible aerobic biodegradation processes, while transport was not possible in fine-grained soils such as clay. Electro-osmotic flow did not contribute to the transport of oxygen, and an increase in voltage gradients produced higher oxygen transfer rates. However, only a minimum fraction of the electrolytically generated oxygen was efficiently used, and the maximum oxygen transport rate observed, approximately 1.4 mgO2 L(-1)d(-1), was rather low, so this technique could be only tested in slow in-situ biostimulation processes for organics removal from polluted soils. PMID:25173714

  9. Optimization of water and nitrogen application to menthol mint (Mentha arvensis L.) through sugarcane trash mulch in a sandy loam soil of semi-arid subtropical climate.

    PubMed

    Ram, Dasha; Ram, Muni; Singh, Ranjeet

    2006-05-01

    Studies were carried out to optimize the use of water and nutrients by the crop with three moisture regimes [0.9, 1.2 and 1.5 irrigation water:cumulative pan evaporation (IW:CPE) ratios], two variables of organic mulch (control and sugarcane trash at 7 t/ha) and three levels of nitrogen (0, 100 and 200 kg/ha). Soil moisture regimes maintained at 1.2 IW:CPE ratio significantly increased the crop growth and herb and essential oil yields as compared with that of 0.9 IW:CPE ratio. The increase in herb yield due to 1.5 and 1.2 IW:CPE ratios was recorded to be 28.5% and 19%, respectively, over the irrigation given at 0.9 IW:CPE ratio, with the corresponding increase in essential oil yield to the extent of 23.5% and 15.5%. Interaction effect of moisture regimes and nitrogen rates indicated that increasing levels of irrigation at the highest level of N (200 kg/ha) improved essential oil yield of the crop. Application of N at 200 kg/ha in the mulched plots significantly enhanced the N uptake by the crop and essential oil yield over the control and 100 kg N/ha applied in the mulched/or unmulched plots and 200 kg N/ha applied in the unmulched plots. Application of organic mulch and nitrogen at 200 kg/ha improved the water use efficiency (WUE) in menthol mint crop. Higher moisture regimes maintained up to 1.2 IW:CPE ratio increased the WUE. The quality of essential oil in terms of its major constituent, menthol, improved slightly with 1.2 IW:CPE ratio as compared to 0.9 and 1.5 IW:CPE ratios at first and second harvests of the crop. It is recommended that menthol mint crop could be grown profitably by providing 16 irrigations, that is 80 cm water (based on 1.2 IW:CPE ratio) and nitrogen at 200 kg/ha in the sugarcane trash mulched plots, which could give a highest benefit:cost ratio from menthol mint cropping.

  10. Alkanindiges illinoisensis gen. nov., sp. nov., an obligately hydrocarbonoclastic, aerobic squalane-degrading bacterium isolated from oilfield soils.

    PubMed

    Bogan, Bill W; Sullivan, Wendy R; Kayser, Kevin J; Derr, K D; Aldrich, Henry C; Paterek, J Robert

    2003-09-01

    An alkane-degrading bacterium, designated GTI MVAB Hex1(T), was isolated from chronically crude oil-contaminated soil from an oilfield in southern Illinois. The isolate grew very weakly or not at all in minimal or rich media without hydrocarbons. Straight-chain aliphatic hydrocarbons, such as hexadecane and heptadecane, greatly stimulated growth; shorter-chain (

  11. Virus removal during simulated soil-aquifer treatment.

    PubMed

    Quanrud, David M; Carroll, Sean M; Gerba, Charles P; Arnold, Robert G

    2003-02-01

    Removals of indigenous coliphage and seeded poliovirus type 1 during simulated soil-aquifer treatment were evaluated during transport of secondary effluent under unsaturated flow conditions in 1-m soil columns. Independent variables included soil type (river sand or sandy loam) and infiltration rate. Removal of coliphage was in all cases less than removal of poliovirus type 1 (strain LSc-2ab), supporting contentions that indigenous coliphage can act as a conservative indicator of groundwater contamination by viral pathogens of human origin. Coliphage retention was significantly more efficient (p<0.001) in the finer-grained sandy loam (93%) than in sand (76%). Increasing reactor detention time from 5 to 20 h increased coliphage attenuation from 70% to 99% in a 1-m sand column. There was a significant linear correlation (p=0.012) between log-transformed (fractional) coliphage concentration [log(C/C(0))] and reactor detention time. Re-mobilization of attached coliphage occurred during simulated rainfall using low-ionic-strength water. Inhibition of aerobic respiration resulted in significantly less efficient coliphage attenuation (p=0.033), suggesting the involvement of aerobic microorganisms in the survival/retention of this virus.

  12. Hurricane Sandy Prowls the Eastern Seaboard

    NASA Video Gallery

    An animation of satellite observations from Oct. 26-29, 2012, shows Hurricane Sandy move along the U.S. East coast and into the Mid-Atlantic and northeastern U.S. Sandy had still not made landfall ...

  13. Hurricane Sandy -- Pass 1, Oct. 29, 2012

    NASA Video Gallery

    Hurricane Sandy was viewed Monday morning from the International Space Station as it orbited 260 miles above the Atlantic Ocean. Sandy had sustained winds of 90 miles an hour as the station passed ...

  14. Hurricane Sandy -- Pass 2, Oct. 29, 2012

    NASA Video Gallery

    Hurricane Sandy was viewed Monday morning from the International Space Station as it orbited 260 miles above the Atlantic Ocean. Sandy had sustained winds of 90 miles an hour as the station passed ...

  15. On Sandy Shores. Teacher's Guide.

    ERIC Educational Resources Information Center

    Strang, Craig; And Others

    The activities in this guide (for grades 2-4) transport students to the sandy shore, one of the most fascinating ecosystems on the planet. At this ecological juncture a multiplicity of life forms find ways to survive, thrive, and interact with each other. Using a wide variety of learning formats, students explore and deepen their understanding of…

  16. Bioremediation of endosulfan contaminated soil and water -- optimization of operating conditions in laboratory scale reactors.

    PubMed

    Kumar, Mathava; Philip, Ligy

    2006-08-21

    A mixed bacterial culture consisted of Staphylococcus sp., Bacillus circulans-I and -II has been enriched from contaminated soil collected from the vicinity of an endosulfan processing industry. The degradation of endosulfan by mixed bacterial culture was studied in aerobic and facultative anaerobic conditions via batch experiments with an initial endosulfan concentration of 50mg/L. After 3 weeks of incubation, mixed bacterial culture was able to degrade 71.58+/-0.2% and 75.88+/-0.2% of endosulfan in aerobic and facultative anaerobic conditions, respectively. The addition of external carbon (dextrose) increased the endosulfan degradation in both the conditions. The optimal dextrose concentration and inoculum size was estimated as 1g/L and 75mg/L, respectively. The pH of the system has significant effect on endosulfan degradation. The degradation of alpha endosulfan was more compared to beta endosulfan in all the experiments. Endosulfan biodegradation in soil was evaluated by miniature and bench scale soil reactors. The soils used for the biodegradation experiments were identified as clayey soil (CL, lean clay with sand), red soil (GM, silty gravel with sand), sandy soil (SM, silty sand with gravel) and composted soil (PT, peat) as per ASTM (American society for testing and materials) standards. Endosulfan degradation efficiency in miniature soil reactors were in the order of sandy soil followed by red soil, composted soil and clayey soil in both aerobic and anaerobic conditions. In bench scale soil reactors, endosulfan degradation was observed more in the bottom layers. After 4 weeks, maximum endosulfan degradation efficiency of 95.48+/-0.17% was observed in red soil reactor where as in composted soil-I (moisture 38+/-1%) and composted soil-II (moisture 45+/-1%) it was 96.03+/-0.23% and 94.84+/-0.19%, respectively. The high moisture content in compost soil reactor-II increased the endosulfan concentration in the leachate. Known intermediate metabolites of

  17. Aerobic rice mechanization: techniques for crop establishment

    NASA Astrophysics Data System (ADS)

    Khusairy, K. M.; Ayob, H.; Chan, C. S.; Fauzi, M. I. Mohamed; Mohamad Fakhrul, Z. O.; Shahril Shah, G. S. M.; Azlan, O.; Rasad, M. A.; Hashim, A. M.; Arshad, Z.; E, E. Ibrahim; Saifulizan, M. N.

    2015-12-01

    Rice being the staple food crops, hundreds of land races in it makes the diversity of rice crops. Aerobic rice production was introduced which requires much less water input to safeguard and sustain the rice production and conserve water due to decreasing water resources, climatic changes and competition from urban and industrial users. Mechanization system plays an important role for the success of aerobic rice cultivation. All farming activities for aerobic rice production are run on aerobic soil conditions. Row seeder mechanization system is developed to replace conventional seeding technique on the aerobic rice field. It is targeted for small and the large scale aerobic rice farmers. The aero - seeder machine is used for the small scale aerobic rice field, while the accord - seeder is used for the large scale aerobic rice field. The use of this mechanization machine can eliminate the tedious and inaccurate seeding operations reduce labour costs and increases work rate. The machine is easy to operate and it can increase crop establishment rate. It reduce missing hill, increasing planting and crop with high yield can be produce. This machine is designed for low costs maintenance and it is easy to dismantle and assemble during maintenance and it is safe to be used.

  18. Dissipation of phenanthrene and pyrene at the aerobic-anaerobic soil interface: differentiation induced by the rhizosphere of PAH-tolerant and PAH-sensitive rice (Oryza sativa L.) cultivars.

    PubMed

    He, Yan; Xia, Wen; Li, Xinfeng; Lin, Jiajiang; Wu, Jianjun; Xu, Jianming

    2015-03-01

    A pot experiment was conducted to reveal the removal of two polycyclic aromatic hydrocarbons (PAHs) (phenanthrene, PHE, and pyrene, PYR) during rice cultivation in a paddy field. The rhizosphere effect on facilitating dissipation of PAHs varied simultaneously as a function of soil properties, PAH types, cultivation time, and genotypes within rice cultivars, with differences performed for PYR but not PHE. Changes in soil PLFA profiles evidenced that the growth of rice roots modified the dominant species within rhizosphere microbial communities and induced a selective enrichment of Gram-negative aerobic bacteria capable of degrading, thereby resulting in the differentiated dissipation of PYR. While the insignificant differences in PHE dissipation might be attributed to its higher solubility and availability under flooded condition that concealed the differences in improvement of bioavailability for microorganisms between rhizosphere and non-rhizosphere, and between both soils and both rice cultivars. Our findings illustrate that the removal of PAHs in paddy soils was more complex relative to those in dryland soils. This was possibly due to the specialty of rice roots for oxygen secretion that provides development of redox heterogeneous microbial habitats at root-soil interface under flooded condition.

  19. Differential sensitivity of aerobic gram-positive and gram-negative microorganisms to 2,4,6-trinitrotoluene (TNT) leads to dissimilar growth and TNT transformation: Results of soil and pure culture studies

    SciTech Connect

    Fuller, M.E.; Manning, J.F. Jr.

    1996-07-30

    The effects of 2,4,6-trinitrotoluene (TNT) on indigenous soil populations and pure bacterial cultures were examined. The number of colony-forming units (CFU) appearing when TNT-contaminated soil was spread on 0.3% molasses plates decreased by 50% when the agar was amended with 67 {mu}g TNT mL{sup -1}, whereas a 99% reduction was observed when uncontaminated soil was plated. Furthermore, TNT-contaminated soil harbored a greater number of organisms able to grow on plates amended with greater than 10 {mu}g TNT mL{sup -1}. The percentage of gram-positive isolates was markedly less in TNT-contaminated soil (7%; 2 of 30) than in uncontaminated soil (61%; 20 of 33). Pseudomonas aeruginosa, Pseudomonas corrugate, Pseudomonasfluorescens and Alcaligenes xylosoxidans made up the majority of the gram-negative isolates from TNT-contaminated soil. Gram-positive isolates from both soils demonstrated marked growth inhibition when greater than 8-16 {mu}g TNT mL{sup -1} was present in the culture media. Most pure cultures of known aerobic gram-negative organisms readily degraded TNT and evidenced net consumption of reduced metabolites. However, pure cultures of aerobic gram-positive bacteria were sensitive to relatively low concentrations of TNT as indicated by the 50% reduction in growth and TNT transformation which was observed at approximately 10 {mu}g TNT mL{sup -1}. Most non-sporeforming gram-positive organisms incubated in molasses media amended with 80 {mu}g TNT mL{sup -1} or greater became unculturable, whereas all strains tested remained culturable when incubated in mineral media amended with 98 {mu}g TNT mL{sup -1}, indicating that TNT sensitivity is likely linked to cell growth. These results indicate that gram-negative organisms are most likely responsible for any TNT transformation in contaminated soil, due to their relative insensitivity to high TNT concentrations and their ability to transform TNT.

  20. Reorganization of vegetation, hydrology and soil carbon after permafrost degradation across heterogeneous boreal landscapes

    USGS Publications Warehouse

    Jorgenson, M. Torre; Harden, Jennifer; Kanevskiy, Mikhail; O'Donnell, Jonathan; Wickland, Kim; Ewing, Stephanie; Manies, Kristen; Zhuang, Qianlai; Shur, Yuri; Striegl, Robert; Koch, Josh

    2013-01-01

    The diversity of ecosystems across boreal landscapes, successional changes after disturbance and complicated permafrost histories, present enormous challenges for assessing how vegetation, water and soil carbon may respond to climate change in boreal regions. To address this complexity, we used a chronosequence approach to assess changes in vegetation composition, water storage and soil organic carbon (SOC) stocks along successional gradients within four landscapes: (1) rocky uplands on ice-poor hillside colluvium, (2) silty uplands on extremely ice-rich loess, (3) gravelly–sandy lowlands on ice-poor eolian sand and (4) peaty–silty lowlands on thick ice-rich peat deposits over reworked lowland loess. In rocky uplands, after fire permafrost thawed rapidly due to low ice contents, soils became well drained and SOC stocks decreased slightly. In silty uplands, after fire permafrost persisted, soils remained saturated and SOC decreased slightly. In gravelly–sandy lowlands where permafrost persisted in drier forest soils, loss of deeper permafrost around lakes has allowed recent widespread drainage of lakes that has exposed limnic material with high SOC to aerobic decomposition. In peaty–silty lowlands, 2–4 m of thaw settlement led to fragmented drainage patterns in isolated thermokarst bogs and flooding of soils, and surface soils accumulated new bog peat. We were not able to detect SOC changes in deeper soils, however, due to high variability. Complicated soil stratigraphy revealed that permafrost has repeatedly aggraded and degraded in all landscapes during the Holocene, although in silty uplands only the upper permafrost was affected. Overall, permafrost thaw has led to the reorganization of vegetation, water storage and flow paths, and patterns of SOC accumulation. However, changes have occurred over different timescales among landscapes: over decades in rocky uplands and gravelly–sandy lowlands in response to fire and lake drainage, over decades to

  1. Teaching Aerobic Fitness Concepts.

    ERIC Educational Resources Information Center

    Sander, Allan N.; Ratliffe, Tom

    2002-01-01

    Discusses how to teach aerobic fitness concepts to elementary students. Some of the K-2 activities include location, size, and purpose of the heart and lungs; the exercise pulse; respiration rate; and activities to measure aerobic endurance. Some of the 3-6 activities include: definition of aerobic endurance; heart disease risk factors;…

  2. Science and Sandy: Lessons Learned

    NASA Astrophysics Data System (ADS)

    Werner, K.

    2013-12-01

    Following Hurricane Sandy's impact on the mid-Atlantic region, President Obama established a Task Force to '...ensure that the Federal Government continues to provide appropriate resources to support affected State, local, and tribal communities to improve the region's resilience, health, and prosperity by building for the future.' The author was detailed from NOAA to the Task Force between January and June 2013. As the Task Force and others began to take stock of the region's needs and develop plans to address them, many diverse approaches emerged from different areas of expertise including: infrastructure, management and construction, housing, public health, and others. Decision making in this environment was complex with many interests and variables to consider and balance. Although often relevant, science and technical expertise was not always at the forefront of this process. This talk describes the author's experience with the Sandy Task Force focusing on organizing scientific expertise to support the work of the Task Force. This includes a description of federal activity supporting Sandy recovery efforts, the role of the Task Force, and lessons learned from developing a science support function within the Task Force.

  3. Ecological Framework For Assessing Changes In Soil Water And Carbon In Response To Degrading Permafrost

    NASA Astrophysics Data System (ADS)

    Jorgenson, T.

    2011-12-01

    The response of soil water and carbon to permafrost degradation differs greatly across the varied terrain of boreal Alaska. Responses can be broadly partitioned among rocky uplands on ice poor bedrock and colluvial deposits, loamy uplands on extremely ice rich Pleistocene loess, sandy lowlands on sand sheets, and peaty lowlands on abandoned floodplains, retransported deposits on lower slopes, and lowland loess. On rocky uplands, soil carbon and water stocks are low and most carbon and water is lost after fire and subsequent thawing of permafrost. On loamy uplands, much of the soil carbon is lost after fire, but soils remain saturated after thawing of the ice rich intermediate layer. Deeper permafrost is resilient. On sandy lowlands, forest soils have low carbon stocks and water contents, in contrast to the high carbon stocks in perched lakes maintained by permafrost. Thawing of permafrost leads to drying of forest soils and draining of lakes, exposing soil carbon to aerobic conditions for decomposition. Peaty lowlands have thick peat deposits associated with black spruce permafrost plateaus and unfrozen collapse-scar bogs and fens. Thawing leads to 2 to 4 m of collapse and large loss of ice.Formation of bogs impounds water in depressions and leads to rapid accumulation of bog peat. Thawing of forest peat also leads to substantial decomposition of old forest peat.

  4. Summary report on the aerobic degradation of diesel fuel and the degradation of toluene under aerobic, denitrifying and sulfate reducing conditions

    SciTech Connect

    Coyne, P.; Smith, G.

    1995-08-15

    This report contains a number of studies that were performed to better understand the technology of the biodegradation of petroleum hydrocarbons. Topics of investigation include the following: diesel fuel degradation by Rhodococcus erythropolis; BTEX degradation by soil isolates; aerobic degradation of diesel fuel-respirometry; aerobic degradation of diesel fuel-shake culture; aerobic toluene degradation by A3; effect of HEPES, B1, and myo-inositol addition on the growth of A3; aerobic and anaerobic toluene degradation by contaminated soils; denitrifying bacteria MPNs; sulfate-reducing bacteria MPNs; and aerobic, DNB and SRB enrichments.

  5. SANDY CREEK ROADLESS AREA, MISSISSIPPI.

    USGS Publications Warehouse

    Haley, Boyd R.; Bitar, Richard F.

    1984-01-01

    The Sandy Creek Roadless Area includes about 3. 7 sq mi in the southeastern part of Adams County, Mississippi. On the basis of a mineral survey, the area offers little promise for the occurrence of metallic mineral resources but has a probable resource potential for oil and natural gas. It is possible that wells drilled deep enough to penetrate the older reservoirs will encounter significant quantities of oil and natural gas in the roadless area. The deposits of gravel, sand, and clay present in the area could be utilized in the construction industry, but similar deposits elsewhere are much closer to available markets.

  6. Abamectin in soils: Analytical methods, kinetics, sorption and dissipation.

    PubMed

    Dionisio, Andreza Camilotti; Rath, Susanne

    2016-05-01

    Abamectin is a broad-spectrum antiparasitic agent that has been widely employed in veterinary medicine and has also been used as a pesticide in agriculture. Veterinary drugs may reach the soil and may be transported to surface and ground waters, posing risks to terrestrial and aquatic organisms. Sorption, transformation and transport processes are primarily responsible for the fate of these substances in the environment. In this study, the sorption and the aerobic dissipation of abamectin in Brazilian soils (sand, clay and sandy-clay) were evaluated. For sorption studies, batch equilibrium experiments were performed. Sorption and desorption isotherms were fitted to the Freundlich model. Abamectin showed a high affinity to soil particles, with Freundlich sorption and desorption coefficients ranging from 44 to 138 μg(1-1/n) (cm(3))(1/n) g(-1) and from 89 to 236 μg(1-1/n) (cm(3))(1/n) g(-1), respectively. Dissipation of abamectin was evaluated in sterile and non-sterile soils in an aerobic and dark environment under controlled temperature and humidity. The time required for a 50% reduction of the amount of abamectin present in non-sterile soils was up to 4 days, and the time period for 90% dissipation was up to 12 days. In sterilized soils, there was no reduction in the concentration of abamectin over 37 days of exposure, suggesting that aerobic microbial degradation must have been the primary mechanism responsible for the dissipation of abamectin in soils. PMID:26923238

  7. Soil property control of biogeochemical processes beneath two subtropical stormwater infiltration basins.

    PubMed

    O'Reilly, Andrew M; Wanielista, Martin P; Chang, Ni-Bin; Harris, Willie G; Xuan, Zhemin

    2012-01-01

    Substantially different biogeochemical processes affecting nitrogen fate and transport were observed beneath two stormwater infiltration basins in north-central Florida. Differences are related to soil textural properties that deeply link hydroclimatic conditions with soil moisture variations in a humid, subtropical climate. During 2008, shallow groundwater beneath the basin with predominantly clayey soils (median, 41% silt+clay) exhibited decreases in dissolved oxygen from 3.8 to 0.1 mg L and decreases in nitrate nitrogen (NO-N) from 2.7 mg L to <0.016 mg L, followed by manganese and iron reduction, sulfate reduction, and methanogenesis. In contrast, beneath the basin with predominantly sandy soils (median, 2% silt+clay), aerobic conditions persisted from 2007 through 2009 (dissolved oxygen, 5.0-7.8 mg L), resulting in NO-N of 1.3 to 3.3 mg L in shallow groundwater. Enrichment of δN and δO of NO combined with water chemistry data indicates denitrification beneath the clayey basin and relatively conservative NO transport beneath the sandy basin. Soil-extractable NO-N was significantly lower and the copper-containing nitrite reductase gene density was significantly higher beneath the clayey basin. Differences in moisture retention capacity between fine- and coarse-textured soils resulted in median volumetric gas-phase contents of 0.04 beneath the clayey basin and 0.19 beneath the sandy basin, inhibiting surface/subsurface oxygen exchange beneath the clayey basin. Results can inform development of soil amendments to maintain elevated moisture content in shallow soils of stormwater infiltration basins, which can be incorporated in improved best management practices to mitigate NO impacts.

  8. Soil property control of biogeochemical processes beneath two subtropical stormwater infiltration basins

    USGS Publications Warehouse

    O'Reilly, Andrew M.; Wanielista, Martin P.; Chang, Ni-Bin; Harris, Willie G.; Xuan, Zhemin

    2012-01-01

    Substantially different biogeochemical processes affecting nitrogen fate and transport were observed beneath two stormwater infiltration basins in north-central Florida. Differences are related to soil textural properties that deeply link hydroclimatic conditions with soil moisture variations in a humid, subtropical climate. During 2008, shallow groundwater beneath the basin with predominantly clayey soils (median, 41% silt+clay) exhibited decreases in dissolved oxygen from 3.8 to 0.1 mg L-1 and decreases in nitrate nitrogen (NO3-–N) from 2.7 mg L-1 to -1, followed by manganese and iron reduction, sulfate reduction, and methanogenesis. In contrast, beneath the basin with predominantly sandy soils (median, 2% silt+clay), aerobic conditions persisted from 2007 through 2009 (dissolved oxygen, 5.0–7.8 mg L-1), resulting in NO3-–N of 1.3 to 3.3 mg L-1 in shallow groundwater. Enrichment of d15N and d18O of NO3- combined with water chemistry data indicates denitrification beneath the clayey basin and relatively conservative NO3- transport beneath the sandy basin. Soil-extractable NO3-–N was significantly lower and the copper-containing nitrite reductase gene density was significantly higher beneath the clayey basin. Differences in moisture retention capacity between fine- and coarse-textured soils resulted in median volumetric gas-phase contents of 0.04 beneath the clayey basin and 0.19 beneath the sandy basin, inhibiting surface/subsurface oxygen exchange beneath the clayey basin. Results can inform development of soil amendments to maintain elevated moisture content in shallow soils of stormwater infiltration basins, which can be incorporated in improved best management practices to mitigate NO3- impacts.

  9. 1. SANDY RIVER BRIDGE AT TROUTDALE, SOUTH END, LOOKING 18 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. SANDY RIVER BRIDGE AT TROUTDALE, SOUTH END, LOOKING 18 DEGREES NORTH. SAME PHOTO AS OR-36-1. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  10. 5. SANDY RIVER BRIDGE AT TROUTDALE, EAST ELEVATION DETAIL, LOOKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. SANDY RIVER BRIDGE AT TROUTDALE, EAST ELEVATION DETAIL, LOOKING 6 DEGREES NORTH. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  11. 3. SANDY RIVER BRIDGE AT TROUTDALE, NORTH END, LOOKING 184 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    3. SANDY RIVER BRIDGE AT TROUTDALE, NORTH END, LOOKING 184 DEGREES SOUTH. SAME PHOTO AS OR-36-2. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  12. 4. SANDY RIVER BRIDGE AT TROUTDALE, NORTH END, LOOKING 224 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    4. SANDY RIVER BRIDGE AT TROUTDALE, NORTH END, LOOKING 224 DEGREES SOUTHWEST. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  13. 7. SANDY RIVER BRIDGE AT TROUTDALE, PERSPECTIVE LOOKING EAST. ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    7. SANDY RIVER BRIDGE AT TROUTDALE, PERSPECTIVE LOOKING EAST. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  14. 6. SANDY RIVER BRIDGE AT TROUTDALE, EAST ELEVATION, LOOKING 306 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. SANDY RIVER BRIDGE AT TROUTDALE, EAST ELEVATION, LOOKING 306 DEGREES NORTHWEST. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  15. 2. SANDY RIVER BRIDGE AT TROUTDALE, SOUTH END, LOOKING 20 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. SANDY RIVER BRIDGE AT TROUTDALE, SOUTH END, LOOKING 20 DEGREES NORTH. - Historic Columbia River Highway, Sandy River Bridge at Troutdale, Historic Columbia River Highway spanning Sandy River, Troutdale, Multnomah County, OR

  16. Treatment of contaminated groundwater in sandy layer under river bank by electrokinetic and ultrasonic technology.

    PubMed

    Chung, Ha I

    2007-01-01

    A series of laboratory experiments involving simple, ultrasonic, electrokinetic, electrokinetic/ ultrasonic flushing test were carried out for treatment and removal of heavy metal and hydrocarbon from contaminated groundwater in sandy layers under a river bank. The test results show that the electrokinetic/ultrasonic flushing technique is most effective for the removal of heavy metal and hydrocarbon from contaminated sandy layers by the coupling action of their own phenomena. It is shown that the electrokinetic technique is most effective to enhance the removal efficiency of heavy metal contaminants such as cadmium from contaminated sandy soil under the river bank; on the other hand the ultrasonic technique is most effective to enhance the removal efficiency of hydrocarbon contaminant, such as diesel fuel from contaminated soil. PMID:17305157

  17. Treatment of contaminated groundwater in sandy layer under river bank by electrokinetic and ultrasonic technology.

    PubMed

    Chung, Ha I

    2007-01-01

    A series of laboratory experiments involving simple, ultrasonic, electrokinetic, electrokinetic/ ultrasonic flushing test were carried out for treatment and removal of heavy metal and hydrocarbon from contaminated groundwater in sandy layers under a river bank. The test results show that the electrokinetic/ultrasonic flushing technique is most effective for the removal of heavy metal and hydrocarbon from contaminated sandy layers by the coupling action of their own phenomena. It is shown that the electrokinetic technique is most effective to enhance the removal efficiency of heavy metal contaminants such as cadmium from contaminated sandy soil under the river bank; on the other hand the ultrasonic technique is most effective to enhance the removal efficiency of hydrocarbon contaminant, such as diesel fuel from contaminated soil.

  18. Fate of the nonsteroidal anti-inflammatory drug naproxen in agricultural soil receiving liquid municipal biosolids.

    PubMed

    Topp, Edward; Hendel, John G; Lapen, David R; Chapman, Ralph

    2008-10-01

    Naproxen (2-(6-methoxy-2-naphthyl) propionic acid) is widely used for the treatment of pain and swelling associated with arthritis, gout, and other inflammatory conditions. Naproxen has been detected in municipal sewage outflows and in surface waters and could reach agricultural land through the application of municipal biosolids or reclaimed water. The persistence characteristics of naproxen in three agricultural soils were investigated. In laboratory microcosms of moist soil incubated at 30 degrees C, [O-14CH3]naproxen was rapidly and thoroughly mineralized to 14CO2 with comparable kinetics in a sandy loam soil, a loam soil, and a silt loam soil. Naproxen mineralization was responsive to soil temperature and soil moisture content, consistent with the primary mechanism of dissipation being biodegradation. Mineralization of naproxen was hastened by the addition of liquid municipal biosolids (LMBs) from a municipal sewage treatment plant that aerated this material. Naproxen was stable in autoclaved soils with or without addition of autoclaved LMBs, whereas naproxen was rapidly mineralized in sterile soil supplemented with nonsterile LMBs. An enrichment culture was obtained from aerobically digested LMBs in a mineral salts medium with naproxen as the sole source of carbon. The culture converted the parent compound to the corresponding naphthol, O-desmethyl naproxen. In summary, naproxen was rapidly removed from soil, with mesophilic aerobic biodegradation being the primary mechanism of dissipation. Microorganisms carried in biosolids enhanced naproxen dissipation in soil, with the initial mechanism of attack likely being O-demethylation. We conclude on this basis that naproxen in soils receiving biosolids would be readily biodegradable and, in the absence of preferential flow or runoff, pose little risk for contamination of adjacent water or crops. PMID:18419173

  19. Hurricane Sandy From the International Space Station

    NASA Video Gallery

    The International Space Station flew high above Hurricane Sandy just before 12 p.m. CDT Thursday. The storm was located about 85 miles south-southeast of Great Exuma Island. The storm’s maximum s...

  20. Aerobic Conditioning Class.

    ERIC Educational Resources Information Center

    Johnson, Neil R.

    1980-01-01

    An aerobic exercise class that focuses on the conditioning of the cardiovascular and muscular systems is presented. Students complete data cards on heart rate, pulse, and exercises to be completed during the forty minute course. (CJ)

  1. Response of aerobic rice to Piriformospora indica.

    PubMed

    Das, Joy; Ramesh, K V; Maithri, U; Mutangana, D; Suresh, C K

    2014-03-01

    Rice cultivation under aerobic condition not only saves water but also opens up a splendid scope for effective application of beneficial root symbionts in rice crop unlike conventional puddled rice cultivation where water logged condition acts as constraint for easy proliferation of various beneficial soil microorganisms like arbuscular mycorrhizal (AM) fungi. Keeping these in view, an in silico investigation were carried out to explore the interaction of hydrogen phosphate with phosphate transporter protein (PTP) from P. indica. This was followed by greenhouse investigation to study the response of aerobic rice to Glomusfasciculatum, a conventional P biofertilizer and P. indica, an alternative to AM fungi. Computational studies using ClustalW tool revealed several conserved motifs between the phosphate transporters from Piriformospora indica and 8 other Glomus species. The 3D model of PTP from P. indica resembling "Mayan temple" was successfully docked onto hydrogen phosphate, indicating the affinity of this protein for inorganic phosphorus. Greenhouse studies revealed inoculation of aerobic rice either with P. indica, G. fasciculatum or both significantly enhanced the plant growth, biomass and yield with higher NPK, chlorophyll and sugar compared to uninoculated ones, P. indica inoculated plants being superior. A significantly enhanced activity of acid phosphatase and alkaline phosphatase were noticed in the rhizosphere soil of rice plants inoculated either with P. indica, G. fasciculatum or both, contributing to higher P uptake. Further, inoculation of aerobic rice plants with P. indica proved to be a better choice as a potential biofertilizer over mycorrhiza. PMID:24669667

  2. Aerobic decomposition of crop residues improves N availability and grain yield for three rice soils of the Mekong Delta, Vietnam: A screenhouse study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the Mekong Delta of Vietnam, rice (Oryza sativa, L.) is usually planted two to three times annually. Limited evidence elsewhere suggests that rice crop uptake of soil nitrogen (N) under such intensive cropping can be increased by replacing the customary anaerobic decomposition of crop residues wi...

  3. [Effect of grazing on sandy grassland ecosystem in Inner Mongolia].

    PubMed

    Zhao, Halin; Zhang, Tonghui; Zhao, Xueyong; Zhou, Ruilian

    2004-03-01

    This experiment was carried out for 5 years in Horqin sandy land, lnner Mongolia, which had 4 treatments: Non-grazing (NG), light grazing (LG), moderate grazing (MG) and over grazing (OG). The results showed that different grazing intensities resulted in different development trend of the pasture ecosystem, of which, the injury of OG on pasture ecosystem was very great. The plant diversity, vegetation coverage, plant height and primary productivity under continuous overgrazing for 5 year were 87.9%, 82.1%, 94.0% and 57.0%, respectively, lower than those in NG. The biomass on the OG pasture was only 2.1% of NG, and the contents of soil clay, C and N as well as the quantities of soil microbes and small animals in OG were respectively 6.0%, 31.9%, 25.0%, 95.0% and 75.9% lower than those in NG, but the soil hardness was raised by 274.0%. Especially, the secondary productivity of the pasture became negative from the third year, and the productive foundation of the pasture ecosystem was completely destroyed. Non-grazing was beneficial to pasture, and enclosure caused an increase in vegetation coverage, plant height and primary productivity. The vegetation coverage, plant height and soil status in LG and MG were not as good as those in NG, but were stable and didn't show worsening trend. Based on the above results, it's considered that on the sandy pasture in the semi-arid area of Inner Mongolia, the rational grass utilization ratio is 45%-50%, and the suitable loading capacity is 3-4 sheep unit.hm-2. PMID:15227991

  4. Seasonal Dynamics of Water Use Strategy of Two Salix Shrubs in Alpine Sandy Land, Tibetan Plateau.

    PubMed

    Zhu, Yajuan; Wang, Guojie; Li, Renqiang

    2016-01-01

    Water is a limiting factor for plant growth and vegetation dynamics in alpine sandy land of the Tibetan Plateau, especially with the increasing frequency of extreme precipitation events and drought caused by climate change. Therefore, a relatively stable water source from either deeper soil profiles or ground water is necessary for plant growth. Understanding the water use strategy of dominant species in the alpine sandy land ecosystem is important for vegetative rehabilitation and ecological restoration. The stable isotope methodology of δD, δ18O, and δ13C was used to determine main water source and long-term water use efficiency of Salix psammophila and S. cheilophila, two dominant shrubs on interdune of alpine sandy land in northeastern Tibetan Plateau. The root systems of two Salix shrubs were investigated to determine their distribution pattern. The results showed that S. psammophila and S. cheilophila absorbed soil water at different soil depths or ground water in different seasons, depending on water availability and water use strategy. Salix psammophila used ground water during the growing season and relied on shallow soil water recharged by rain in summer. Salix cheilophila used ground water in spring and summer, but relied on shallow soil water recharged by rain in spring and deep soil water recharged by ground water in fall. The two shrubs had dimorphic root systems, which is coincident with their water use strategy. Higher biomass of fine roots in S. psammophila and longer fine roots in S. cheilophila facilitated to absorb water in deeper soil layers. The long-term water use efficiency of two Salix shrubs increased during the dry season in spring. The long-term water use efficiency was higher in S. psammophila than in S. cheilophila, as the former species is better adapted to semiarid climate of alpine sandy land.

  5. Seasonal Dynamics of Water Use Strategy of Two Salix Shrubs in Alpine Sandy Land, Tibetan Plateau.

    PubMed

    Zhu, Yajuan; Wang, Guojie; Li, Renqiang

    2016-01-01

    Water is a limiting factor for plant growth and vegetation dynamics in alpine sandy land of the Tibetan Plateau, especially with the increasing frequency of extreme precipitation events and drought caused by climate change. Therefore, a relatively stable water source from either deeper soil profiles or ground water is necessary for plant growth. Understanding the water use strategy of dominant species in the alpine sandy land ecosystem is important for vegetative rehabilitation and ecological restoration. The stable isotope methodology of δD, δ18O, and δ13C was used to determine main water source and long-term water use efficiency of Salix psammophila and S. cheilophila, two dominant shrubs on interdune of alpine sandy land in northeastern Tibetan Plateau. The root systems of two Salix shrubs were investigated to determine their distribution pattern. The results showed that S. psammophila and S. cheilophila absorbed soil water at different soil depths or ground water in different seasons, depending on water availability and water use strategy. Salix psammophila used ground water during the growing season and relied on shallow soil water recharged by rain in summer. Salix cheilophila used ground water in spring and summer, but relied on shallow soil water recharged by rain in spring and deep soil water recharged by ground water in fall. The two shrubs had dimorphic root systems, which is coincident with their water use strategy. Higher biomass of fine roots in S. psammophila and longer fine roots in S. cheilophila facilitated to absorb water in deeper soil layers. The long-term water use efficiency of two Salix shrubs increased during the dry season in spring. The long-term water use efficiency was higher in S. psammophila than in S. cheilophila, as the former species is better adapted to semiarid climate of alpine sandy land. PMID:27243772

  6. Seasonal Dynamics of Water Use Strategy of Two Salix Shrubs in Alpine Sandy Land, Tibetan Plateau

    PubMed Central

    Zhu, Yajuan; Wang, Guojie; Li, Renqiang

    2016-01-01

    Water is a limiting factor for plant growth and vegetation dynamics in alpine sandy land of the Tibetan Plateau, especially with the increasing frequency of extreme precipitation events and drought caused by climate change. Therefore, a relatively stable water source from either deeper soil profiles or ground water is necessary for plant growth. Understanding the water use strategy of dominant species in the alpine sandy land ecosystem is important for vegetative rehabilitation and ecological restoration. The stable isotope methodology of δD, δ18O, and δ13C was used to determine main water source and long-term water use efficiency of Salix psammophila and S. cheilophila, two dominant shrubs on interdune of alpine sandy land in northeastern Tibetan Plateau. The root systems of two Salix shrubs were investigated to determine their distribution pattern. The results showed that S. psammophila and S. cheilophila absorbed soil water at different soil depths or ground water in different seasons, depending on water availability and water use strategy. Salix psammophila used ground water during the growing season and relied on shallow soil water recharged by rain in summer. Salix cheilophila used ground water in spring and summer, but relied on shallow soil water recharged by rain in spring and deep soil water recharged by ground water in fall. The two shrubs had dimorphic root systems, which is coincident with their water use strategy. Higher biomass of fine roots in S. psammophila and longer fine roots in S. cheilophila facilitated to absorb water in deeper soil layers. The long-term water use efficiency of two Salix shrubs increased during the dry season in spring. The long-term water use efficiency was higher in S. psammophila than in S. cheilophila, as the former species is better adapted to semiarid climate of alpine sandy land. PMID:27243772

  7. The Topic Is Sandy Hook: A Program for Gifted and Talented Students at Sandy Hook.

    ERIC Educational Resources Information Center

    Grant, David

    "The Topic Is Sandy Hook" is an experiential 10-week program designed to provide special opportunities and educational experiences for 6th to 10th grade gifted and talented students. Sandy Hook, a natural resource in Monmouth County, New Jersey, is unique in its physical and historical features and provides an exceptionally rich environment in…

  8. Dynamic changes of sandy land in northwest of Beijing, China.

    PubMed

    Wang, Jing; He, Ting; Guo, Xudong; Liu, Aixia; Zhou, Qing

    2006-10-01

    The area northwest of Beijing is one of the most important regions where many organizations invest and pay most attention. The environmental problems in this region affect not only Beijing but also the surrounding area. Based on observation of the characteristics of the change in sandy land, this study classified four types of dynamic change of sandy land, including extended sandy land, the reversely changed sandy land, the potential sandy land and no change in sandy land. Then the process and the trend of changes in sandy land and their environmental impact on the area northwest of Beijing were analyzed. The results show that the area of sandy land has increased in this region in the period of 1991 to 2002. Change between sandy land and grassland was the dominant change. It is found that the monitoring zones of Hunshandake sandy land and north of Yin Shan are regions with high ratio of extended sandy land, and are connected with widespread potential change of sandy land. This implies that these two regions have a high probability of increase in sandy land in the future. On the other hand, in the monitoring zone of Horqin sandy land and Ba Shang Plateau and its surrounding area, desertification had been controlled and the area of sandy land is expected to decrease. This indicates that the direction of the sandstorm to Beijing is expected to gradually move to the northwest. Furthermore, the decreases in sandy land and the reversing change from arable land to grassland and forests in the study region will affect the land quality and atmosphere. And the logistic multiple regression (LMR) model was employed to better understand the complexity and processes of increases in sandy land. This model predicts that there is a high probability of increases in sandy land in north of Siziwang Banner, Zhengxiangbai Banner and Zhenglan Banner. Finally, suggestions to the ecological construction of the study area have been proposed. PMID:16758285

  9. Dance--Aerobic and Anaerobic.

    ERIC Educational Resources Information Center

    Cohen, Arlette

    1984-01-01

    This article defines and explains aerobic exercise and its effects on the cardiovascular system. Various studies on dancers are cited indicating that dance is an anaerobic activity with some small degree of aerobic benefit. (DF)

  10. Spatial Patterns and Natural Recruitment of Native Shrubs in a Semi-arid Sandy Land

    PubMed Central

    Wu, Bo; Yang, Hongxiao

    2013-01-01

    Passive restoration depending on native shrubs is an attractive approach for restoring desertified landscapes in semi-arid sandy regions. We sought to understand the relationships between spatial patterns of native shrubs and their survival ability in sandy environments. Furthermore, we applied our results to better understand whether passive restoration is feasible for desertified landscapes in semi-arid sandy regions. The study was conducted in the semi-arid Mu Us sandy land of northern China with the native shrub Artemisia ordosica. We analyzed population structures and patterns of A. ordosica at the edges and centers of land patches where sand was stabilized by A. ordosica-dominated vegetation. Saplings were more aggregated than adults, and both were more aggregated at the patch edges than at the patch centers. At the patch edges, spatial association of the saplings with the adults was mostly positive at distances 0.3–6.6 m, and turned from positive to neutral, and even negative, at other distances. At the patch centers, the saplings were spaced almost randomly around the adults, and their distances from the adults did not seem to affect their locations. A greater number of A. ordosica individuals emerged at the patch edges than at the patch centers. Such patterns may have resulted from their integrative adjustment to specific conditions of soil water supply and sand drift intensity. These findings suggest that in semi-arid sandy regions, native shrubs that are well-adapted to local environments may serve as low-cost and competent ecological engineers that can promote the passive restoration of surrounding patches of mobile sandy land. PMID:23505489

  11. Operational Group Sandy technical progress report

    USGS Publications Warehouse

    ,

    2013-01-01

    This report documents results from the March 2013 deployment of the OGS. It includes background information on Hurricane Sandy and the federal response; the OGS methodology; scenarios for Hurricane Sandy’s impact on coastal communities and urban ecosystems; potential interventions to improve regional resilience to future major storms; a discussion of scenario results; and lessons learned about the OGS process.

  12. A Bad Day for Sandy Dayton.

    ERIC Educational Resources Information Center

    Duch, Barbara

    2000-01-01

    Presents a rear-end car accident scenario to teach about forces and kinetic energy in a problem-based learning format. Includes four parts: (1) "A Bad Day for Sandy Dayton"; (2) "The Emergency Room"; (3) "The Facts of the Case"; and (4) "Judgement Day". Discusses the major issues of the questions, introduces scientific concepts, and initiates…

  13. Post-Sandy, Schools Claw Back

    ERIC Educational Resources Information Center

    Maxwell, Lesli A.

    2012-01-01

    David Weiss, the superintendent in Long Beach, N.Y., wrestled with a slew of considerations last week as he weighed when to restart school, nine days after Hurricane Sandy wrecked his community. Just one of seven buildings had most of the essentials: electricity, heat, working fire alarms, sewage, and food. And, with many students and staff…

  14. A Study of Sandy Beach Zonation.

    ERIC Educational Resources Information Center

    Alexander, Steve K.

    1991-01-01

    Describes the study of sandy beach zonations as a seashore activity for either high school or lower-level college courses in biology, ecology, or marine biology. Students first draw a profile of a beach scene and then collect specimens from the zones of the shore. In a laboratory, students identify their specimens and relate them to the beach…

  15. Fate of the antiretroviral drug tenofovir in agricultural soil.

    PubMed

    Al-Rajab, Abdul Jabbar; Sabourin, Lyne; Chapman, Ralph; Lapen, David R; Topp, Edward

    2010-10-15

    Tenofovir (9-(R)-(2-phosphonylmethoxypropyl)-adenine) is an antiretroviral drug widely used for the treatment of human immunodeficiency virus (HIV-1) and Hepatitis B virus (HBV) infections. Tenofovir is extensively and rapidly excreted unchanged in the urine. In the expectation that tenofovir could potentially reach agricultural lands through the application of municipal biosolids or wastewater, and in the absence of any environmental fate data, we evaluated its persistence in selected agricultural soils. Less than 10% of [adenine-8-(14)C]-tenofovir added to soils varying widely in texture (sand, loam, clay loam) was mineralized in a 2-month incubation under laboratory conditions. Tenofovir was less readily extractable from clay soils than from a loam or a sandy loam soil. Radioactive residues of tenofovir were removed from the soil extractable fraction with DT(50)s ranging from 24±2 to 67+22days (first order kinetic model) or 44+9 to 127+55days (zero order model). No extractable transformation products were detectable by HPLC. Tenofovir mineralization in the loam soil increased with temperature (range 4°C to 30°C), and did not occur in autoclaved soil, suggesting a microbial basis. Mineralization rates increased with soil moisture content, ranging from air-dried to saturated. In summary, tenofovir was relatively persistent in soils, there were no extractable transformation products detected, and the response of [adenine-8-(14)C]-tenofovir mineralization to soil temperature and heat sterilization indicated that the molecule was biodegraded by aerobic microorganisms. Sorption isotherms with dewatered biosolids suggested that tenofovir residues could potentially partition into the particulate fraction during sewage treatment. PMID:20800877

  16. Treatment of Aroclor 1016 contaminated soil by hydrogen peroxide: laboratory column study.

    PubMed

    Viisimaa, Marika; Veressinina, Jelena; Goi, Anna

    2012-09-01

    The potential and feasibility of treating soil contaminated with electrical insulating oil, Aroclor 1016, containing polychlorinated biphenyls (PCBs) with stabilized hydrogen peroxide were evaluated using columns packed with soils of two different matrixes. The column experiments showed that PCBs degraded by the stabilized hydrogen peroxide treatment in both soil matrixes, although the efficacy of the treatment depended strongly on the soil characteristics. The removal of PCB-containing oil was higher in sandy silt soil than in sandy soil. While a higher iron content promoted hydrogen peroxide oxidation of the contaminant in sandy silt soil, lower permeability and higher organic matter content contributed to an oxidation decrease as a function of depth. Dehydrogenase activity measurements indicated no substantial changes in microbial activity during the treatment of both sandy and sandy silt soils, thus offering opportunities to apply the hydrogen peroxide treatment to the remediation of PCB-contaminated soil.

  17. Long-Term Observations of Dust Storms in Sandy Desert Environments

    NASA Astrophysics Data System (ADS)

    Yun, Hye-Won; Kim, Jung-Rack; Choi, Yun-Soo

    2015-04-01

    Mineral dust occupies the largest portion of atmospheric aerosol. Considering the numerous risks that dust poses for socioeconomic and anthropogenic activities, it is crucial to understand sandy desert environments, which frequently generate dust storms and act as a primary source of atmospheric aerosol. To identify mineral aerosol mechanisms, it is essential to monitor desert environmental factors involving dust storm generation in the long term. In this study, we focused on two major environmental factors: local surface roughness and soil moisture. Since installments of ground observation networks in sandy deserts are unfeasible, remote sensing techniques for mining desert environmental factors were employed. The test area was established within the Badain Jaran and Kubuqi Deserts in Inner Mongolia, China, where significant seasonal aeolian processes emit mineral dust that influences all of East Asia. To trace local surface roughness, we employed a multi-angle imaging spectroradiometer (MISR) image sequence to extract multi-angle viewing (MAV) topographic parameters such as normalized difference angular index, which represents characteristics of the target desert topography. The backscattering coefficient from various space-borne SAR and stereotopography were compared with MAV observations to determine calibrated local surface roughness. Soil moisture extraction techniques from InSAR-phase coherence stacks were developed and compiled with advanced scatterometer (ASCAT) soil moisture data. Combined with metrological information such as the European Centre for Medium-Range Weather Forecasts (ECMWF) ERA interim, correlations between intensity of sand dune activity as a proxy of aeolian processes in desert environments, surface wind conditions, and surface soil moisture were traced. Overall, we have confirmed that tracking sandy desert aeolian environments for long-term observations is feasible with space-borne, multi-sensor observations when combined with

  18. [Effects of short-term fencing on organic carbon fractions and physical stability of sandy sierozem in desert steppe of Northwest China].

    PubMed

    Yang, Xin-Guo; Song, Nai-Ping; Li, Xue-Bin; Liu, Bing-Ru

    2012-12-01

    In order to explore the change patterns of organic carbon fractions and physical stability of sandy sierozem in desert steppe at the early stage of fencing, 0-40 cm soil samples were collected from a 5-year fenced desert steppe (inside the fence) and a free grazing steppe (outside the fence) in Yanchi County of Ningxia, Northwest China, with the soil organic carbon, labile organic carbon, and particulate organic carbon contents and soil particle composition analyzed. No significant differences were observed in the soil organic carbon content and soil particle composition inside and outside the fence. The average soil organic carbon inside and outside the fences was 3.25 g x kg(-1), the percentages of sand, silt, and clay were averagely 72%, 16%, and 12%, respectively, and the soil physical stability index was 1.30% -1.31%. The soil active organic carbon showed a significant change in 10-20 cm layer. The soil labile organic carbon content was 0.80 g x kg(-1) inside the fence, which was significantly higher than that outside the fence (0.62 g x kg(-1)). The percentage of soil particulate organic carbon was 50.9% inside the fence, which was also significantly higher than that outside the fence (31.7%). The soil texture inside the fence changed from sandy to loam, and the soil labile organic carbon content increased gradually; while the soil texture outside the fence was sandy, and its vertical change was relatively smooth. The organic carbon of sandy si- erozem in the desert steppe under the conditions of short-term fencing was still in a balance between consumption and accumulation, the soil texture was relatively stable, and the soil physical stability changed little. It was suggested that the soil active organic carbon content and its relative percentage in 10-20 cm layer could be used as the indicators of early soil quality change of desert steppe.

  19. Biochar effects on soil hydrology

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochar has the potential to alter soil hydrology, and these alterations may lead to significant changes in water cycling and ecosystem processes mediated by water. Biochar soil amendment may change infiltration and drainage in both sandy and clay soils, may increase or decrease plant-available wate...

  20. Plant litter and soil type drive abundance, activity and community structure of alkB harbouring microbes in different soil compartments

    PubMed Central

    Schulz, Stephan; Giebler, Julia; Chatzinotas, Antonis; Wick, Lukas Y; Fetzer, Ingo; Welzl, Gerhard; Harms, Hauke; Schloter, Michael

    2012-01-01

    Alkanes are major constituents of plant-derived waxy materials. In this study, we investigated the abundance, community structure and activity of bacteria harbouring the alkane monooxygenase gene alkB, which catalyses a major step in the pathway of aerobic alkane degradation in the litter layer, the litter–soil interface and in bulk soil at three time points during the degradation of maize and pea plant litter (2, 8 and 30 weeks) to improve our understanding about drivers for microbial performance in different soil compartments. Soil cores of different soil textures (sandy and silty) were taken from an agricultural field and incubated at constant laboratory conditions. The abundance of alkB genes and transcripts (by qPCR) as well as the community structure (by terminal restriction fragment polymorphism fingerprinting) were measured in combination with the concentrations and composition of alkanes. The results obtained indicate a clear response pattern of all investigated biotic and abiotic parameters depending on the applied litter material, the type of soil used, the time point of sampling and the soil compartment studied. As expected the distribution of alkanes of different chain length formed a steep gradient from the litter layer to the bulk soil. Mainly in the two upper soil compartments community structure and abundance patterns of alkB were driven by the applied litter type and its degradation. Surprisingly, the differences between the compartments in one soil were more pronounced than the differences between similar compartments in the two soils studied. This indicates the necessity for analysing processes in different soil compartments to improve our mechanistic understanding of the dynamics of distinct functional groups of microbes. PMID:22402403

  1. Transport of gadolinium- and arsenic-based pharmaceuticals in saturated soil under various redox conditions.

    PubMed

    Menahem, Adi; Dror, Ishai; Berkowitz, Brian

    2016-02-01

    The release of pharmaceuticals and personal care products (PPCPs) to the soil-water environment necessitates understanding of PPCP transport behavior under conditions that account for dynamic flow and varying redox states. This study investigates the transport of two organometallic PPCPs, Gd-DTPA and roxarsone (arsenic compound) and their metal salts (Gd(NO3)3, AsNaO2); Gd-DTPA is used widely as a contrasting agent for MRI, while roxarsone is applied extensively as a food additive in the broiler poultry industry. Here, we present column experiments using sand and Mediterranean red sandy clay soil, performed under several redox conditions. The metal salts were almost completely immobile. In contrast, transport of Gd-DTPA and roxarsone was affected by the soil type. Roxarsone was also affected by the different redox conditions, showing delayed breakthrough curves as the redox potential became more negative due to biological activity (chemically-strong reducing conditions did not affect the transport). Mechanisms that include adsorptive retardation for aerobic and nitrate-reducing conditions, and non-adsorptive retardation for iron-reducing, sulfate-reducing and biologically-strong reducing conditions, are suggested to explain the roxarsone behavior. Gd-DTPA is found to be a stable complex, with potential for high mobility in groundwater systems, whereas roxarsone transport through groundwater systems is affected by redox environments, demonstrating high mobility under aerobic and nitrate-reducing conditions and delayed transport under iron-reducing, sulfate-reducing and biologically-strong reducing conditions.

  2. Rebuilding Emergency Care After Hurricane Sandy.

    PubMed

    Lee, David C; Smith, Silas W; McStay, Christopher M; Portelli, Ian; Goldfrank, Lewis R; Husk, Gregg; Shah, Nirav R

    2014-04-01

    A freestanding, 911-receiving emergency department was implemented at Bellevue Hospital Center during the recovery efforts after Hurricane Sandy to compensate for the increased volume experienced at nearby hospitals. Because inpatient services at several hospitals remained closed for months, emergency volume increased significantly. Thus, in collaboration with the New York State Department of Health and other partners, the Health and Hospitals Corporation and Bellevue Hospital Center opened a freestanding emergency department without on-site inpatient care. The successful operation of this facility hinged on key partnerships with emergency medical services and nearby hospitals. Also essential was the establishment of an emergency critical care ward and a system to monitor emergency department utilization at affected hospitals. The results of this experience, we believe, can provide a model for future efforts to rebuild emergency care capacity after a natural disaster such as Hurricane Sandy. (Disaster Med Public Health Preparedness. 2014;0:1-4). PMID:24713152

  3. Estimating the effects of a conversion from submerged to aerobic rice: a case study on a district basis

    NASA Astrophysics Data System (ADS)

    Rienzner, Michele; Facchi, Arianna; Cesari de Maria, Sandra; Chiaradia, Enrico Antonio; Gandolfi, Claudio

    2014-05-01

    Several studies report that the water use efficiency of irrigated rice can greatly improve at the field scale if continuously submerged rice is replaced with aerobic rice. However, the effects of a massive conversion on the groundwater resources of larger domains are much less investigated, even though several authors agree that a consequent drop of the groundwater table may have repercussions on the potential gains. Therefore, a case study was developed in order to assess the effects of replacing all the flooded rice fields (status quo) with aerobic rice (scenario) on both the groundwater level and the irrigation requirements at the scale of an irrigation district. The investigated area is the San Giorgio di Lomellina-East district (Lombardia, Italy). Data available comprise: soil type (sandy soil according to the USDA classification), land cover of the status quo (200 ha of flooded rice, 105 ha of maize and 76 ha of non-irrigated crops), groundwater level measurements by a piezometer within the area, flow rates in the irrigation channels and meteorological data. First, the monthly percolations in the status quo were estimated by considering: i) percolations from flooded rice fields computed as the residual term of the district water balance, ii) percolations from fields with maize and non-irrigated crops obtained by parameterizing and running the model SWAP (boundary conditions given by the average groundwater level of the status quo), iii) percolation from the irrigation channels considering the efficiency of the irrigation network. Then, an autoregressive model with exogenous input was calibrated in order to relate the district percolations and the groundwater levels in the status quo (P-GWL model). Finally, a set of SWAP simulation with increasing groundwater levels was run for each land use (i.e. aerobic rice, maize and non-irrigated crops) so as to find, within the set, the combination percolation-groundwater level which best responds to the P-GWL model. The

  4. Aerobic landfill bioreactor

    DOEpatents

    Hudgins, Mark P; Bessette, Bernard J; March, John C; McComb, Scott T.

    2002-01-01

    The present invention includes a system of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  5. Aerobic landfill bioreactor

    DOEpatents

    Hudgins, Mark P; Bessette, Bernard J; March, John; McComb, Scott T.

    2000-01-01

    The present invention includes a method of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120.degree. F. and 140.degree. F. in steady state.

  6. Aerobic landfill bioreactor

    SciTech Connect

    Hudgins, M.P.; Bessette, B.J.; March, J.; McComb, S.T.

    2000-02-15

    The present invention includes a method of decomposing municipal solid waste (MSW) within a landfill by converting the landfill to aerobic degradation in the following manner: (1) injecting air via the landfill leachate collection system (2) injecting air via vertical air injection wells installed within the waste mass; (3) applying leachate to the waste mass using a pressurized drip irrigation system; (4) allowing landfill gases to vent; and (5) adjusting air injection and recirculated leachate to achieve a 40% to 60% moisture level and a temperature between 120 F and 140 F in steady state.

  7. Low-Impact Aerobics: Better than Traditional Aerobic Dance?

    ERIC Educational Resources Information Center

    Koszuta, Laurie Einstein

    1986-01-01

    A form of dance exercise called low-impact aerobics is being touted as a misery-free form of aerobic dance. Because this activity is relatively new, the exact kinds and frequencies of injuries are not known and the fitness benefits have not been examined. (MT)

  8. Aerobic Fitness and School Children.

    ERIC Educational Resources Information Center

    Hinkle, J. Scott

    1997-01-01

    Provides school counselors with information on aerobic exercise (specifically running) and the psychological, behavioral, and physical benefits children obtained by participating in fitness programs. Recommends collaboration between school counselors and physical education teachers and gives a preliminary discussion of aerobic running and its…

  9. Aerobic Fitness and School Children.

    ERIC Educational Resources Information Center

    Hinkle, J. Scott

    1992-01-01

    Provides school counselors with information regarding aerobic exercise (specifically running), and the psychological, behavioral, and physical benefits children obtain by participating in fitness programs. Presents methods of collaboration between school counselors and physical education teachers. Offers preliminary discussion of aerobic running…

  10. Exercise, Animal Aerobics, and Interpretation?

    ERIC Educational Resources Information Center

    Oliver, Valerie

    1996-01-01

    Describes an aerobic activity set to music for children that mimics animal movements. Example exercises include walking like a penguin or jumping like a cricket. Stresses basic aerobic principles and designing the program at the level of children's motor skills. Benefits include reaching people who normally don't visit nature centers, and bridging…

  11. Monitoring the alkane monooxygenase gene alkB in different soil interfaces during plant litter degradation of C3 and C4 plants

    NASA Astrophysics Data System (ADS)

    Schulz, S.; Munch, J. C.; Schloter, M.

    2009-04-01

    Hydrocarbons like n-alkanes are ubiquitous in the environment as a result of anthropogenic contamination (e.g. oil spills) as well as a part of an ecosystem's biomass. For example n-alkanes become released during plant litter degradation; consequently they become a high abundant carbon source for microorganism. One possibility for the prokaryotic hydrocarbon metabolisation is an aerobic degradation pathway where the initial step is catalysed by the membrane bound alkane monooxygenase alkB. We analysed the influence of alkanes on the abundance of the alkB gene in different interfaces of the litter-soil system during the degradation of maize and pea litter. Therefore soil samples of a sandy and a loamy soil have been incubated with straw of maize and pea plants up to 30 weeks with constant soil moisture and temperature. Using quantitative real-time PCR we were able to monitor the changes of the abundance and the expression rates of alkB. In our experiments we focused on the straw layer, the litter/soil interface and the soil 1 cm below this interface (bulk soil). Our results clearly demonstrate time and space dependent abundance patterns of alkB genes and transcripts in the different layers studied, which are additionally shaped by the soil type used.

  12. Antimony release from contaminated mine soils and its migration in four typical soils using lysimeter experiments.

    PubMed

    Shangguan, Yu-Xian; Zhao, Long; Qin, Yusheng; Hou, Hong; Zhang, Naiming

    2016-11-01

    Antimony (Sb) can pose great risks to the environment in mining and smelting areas. The migration of Sb in contaminated mine soil was studied using lysimeter experiments. The exchangeable concentration of soil Sb decreased with artificial leaching. The concentrations of Sb retained in the subsoil layers (5-25cm deep) were the highest for Isohumosol and Ferrosol and the lowest for Sandy soil. The Sb concentrations in soil solutions decreased with soil depth, and were adequately simulated using a logarithmic function. The Sb migration pattern in Sandy soil was markedly different from the patterns in the other soils which suggested that Sb may be transported in soil colloids. Environmental factors such as water content, soil temperature, and oxidation-reduction potential of the soil had different effects on Sb migration in Sandy soil and Primosol. The high Fe and Mn contents in Ferrosol and Isohumosol significantly decreased the mobility of Sb in these soils. The Na and Sb concentrations in soils used in the experiments positively correlated with each other (P<0.01). The Sb concentrations in soil solutions, the Sb chemical fraction patterns, and the Sb/Na ratios decreased in the order Sandy soil>Primosol>Isohumosol>Ferrosol, and we concluded that the Sb mobility in the soils also decreased in that order. PMID:27395817

  13. Antimony release from contaminated mine soils and its migration in four typical soils using lysimeter experiments.

    PubMed

    Shangguan, Yu-Xian; Zhao, Long; Qin, Yusheng; Hou, Hong; Zhang, Naiming

    2016-11-01

    Antimony (Sb) can pose great risks to the environment in mining and smelting areas. The migration of Sb in contaminated mine soil was studied using lysimeter experiments. The exchangeable concentration of soil Sb decreased with artificial leaching. The concentrations of Sb retained in the subsoil layers (5-25cm deep) were the highest for Isohumosol and Ferrosol and the lowest for Sandy soil. The Sb concentrations in soil solutions decreased with soil depth, and were adequately simulated using a logarithmic function. The Sb migration pattern in Sandy soil was markedly different from the patterns in the other soils which suggested that Sb may be transported in soil colloids. Environmental factors such as water content, soil temperature, and oxidation-reduction potential of the soil had different effects on Sb migration in Sandy soil and Primosol. The high Fe and Mn contents in Ferrosol and Isohumosol significantly decreased the mobility of Sb in these soils. The Na and Sb concentrations in soils used in the experiments positively correlated with each other (P<0.01). The Sb concentrations in soil solutions, the Sb chemical fraction patterns, and the Sb/Na ratios decreased in the order Sandy soil>Primosol>Isohumosol>Ferrosol, and we concluded that the Sb mobility in the soils also decreased in that order.

  14. Threats to sandy beach ecosystems: A review

    NASA Astrophysics Data System (ADS)

    Defeo, Omar; McLachlan, Anton; Schoeman, David S.; Schlacher, Thomas A.; Dugan, Jenifer; Jones, Alan; Lastra, Mariano; Scapini, Felicita

    2009-01-01

    We provide a brief synopsis of the unique physical and ecological attributes of sandy beach ecosystems and review the main anthropogenic pressures acting on the world's single largest type of open shoreline. Threats to beaches arise from a range of stressors which span a spectrum of impact scales from localised effects (e.g. trampling) to a truly global reach (e.g. sea-level rise). These pressures act at multiple temporal and spatial scales, translating into ecological impacts that are manifested across several dimensions in time and space so that today almost every beach on every coastline is threatened by human activities. Press disturbances (whatever the impact source involved) are becoming increasingly common, operating on time scales of years to decades. However, long-term data sets that describe either the natural dynamics of beach systems or the human impacts on beaches are scarce and fragmentary. A top priority is to implement long-term field experiments and monitoring programmes that quantify the dynamics of key ecological attributes on sandy beaches. Because of the inertia associated with global climate change and human population growth, no realistic management scenario will alleviate these threats in the short term. The immediate priority is to avoid further development of coastal areas likely to be directly impacted by retreating shorelines. There is also scope for improvement in experimental design to better distinguish natural variability from anthropogenic impacts. Sea-level rise and other effects of global warming are expected to intensify other anthropogenic pressures, and could cause unprecedented ecological impacts. The definition of the relevant scales of analysis, which will vary according to the magnitude of the impact and the organisational level under analysis, and the recognition of a physical-biological coupling at different scales, should be included in approaches to quantify impacts. Zoning strategies and marine reserves, which have not

  15. CMs work overtime in Sandy's wake.

    PubMed

    2013-01-01

    When Hurricane Sandy devastated parts of Manhattan, Lutheran Medical Center in Brooklyn prepared in advance to handle an influx of patients evacuated from nursing homes and hospitals. Case management staff worked overtime in advance to discharge appropriate patients and free up beds. When evacuated patients came into the emergency department, the staff transferred stable patients to the hospital's own nursing homes and others with available beds, and admitted patients who met inpatient criteria. After the storm passed, case managers worked to discharge more patients to free up beds for injured patients and find placement for patients who presented to the emergency department but didn't meet admission criteria.

  16. Kinetics of biodegradation during remediation of consecutive accidental spills of chlorophenols in a sandy aquifer.

    PubMed

    Antizar-Ladislao, B; Galil, N I

    2003-01-01

    Kinetics of biodegradation of chlorophenols were studied in six sandy aquifer columns (0.06 m I.D.; 1.00 m L). Remediation of chlorophenols was enhanced by using a "closed-loop" configuration system, where local groundwater was recirculated through the polluted site in a controlled manner. Consecutive accidental spills of phenol, 2-monochlorophenol (2-MCP) and 2,4,6-trichlorophenol (2,4,6-TCP) as single pollutants were removed following first order kinetics. The removal of chlorophenols increased by one order of magnitude following consecutive accidental spills demonstrating adaptation of the resident micro flora. The biodegradation rate constants in this study were in the same range and agreed with those reported in the literature for biodegradation in aerobic aquifers. Following the fate of the resident micro flora (enhanced by adding NH4Cl and KH2PO4 at a ratio C/N/P equal to 120:10:1), biomass growth was observed in the sandy aquifer columns and particle size analyses of the aqueous phase recirculated through the polluted site experimentally proved aggregation of cells. Aggregation of cells has been hypothesized as one of the causes for low biodegradation rates found in the field compared to those calculated using biodegradation rate constants determined in batch culture.

  17. Modeling soil climate controls on the exchange of trace gases between the terrestrial biosphere and the atmosphere. Ph.D. Thesis

    SciTech Connect

    Frolking, S.E.

    1993-12-31

    Soil temperature and moisture profiles (soil climate) have a strong influence on the rate of trace gas exchange between the terrestrial biosphere and the atmosphere through the controls exerted on microbial processes and the physical exchange of gases. Principal controls of biological denitrification in mineral soils are the availability of carbon and nitrogen substrates and the soil anaerobic status. A process-oriented model of decomposition and denitrification in soils (DNDC) was modified to have a more detailed portrayal of these controls. In particular, a diffusive soil gas phase was added, along with a method for determining anaerobic and aerobic fractional volume within a soil profile. The model generally overestimated N2O fluxes when compared to field data from a sandy soil in Costa Rica, but captured the timing and shape of the brief flux episodes. Several modelling shortcomings are discussed, including the nature of the carbon substrates and the nature and dynamics of soil anaerobic fractional volume. Methane flux from wetland soils is generally correlated with soil temperature and depth to water table. A model of peat soil climate was developed and applied to a small, poor fen in southern New Hampshire. Temperature profiles and ice depth are in good agreement with field data, but depth to water table is more problematic. Field-based flux correlations to soil temperature, depth to water table, and weighted recent precipitation were developed. When used with the wetland soil climate model, much of the seasonal and shorter period flux variability was captured. The model was then driven by local weather data for 1926-1986; flux variability was dependent on both summer season temperatures and summer precipitation patterns. It is estimated that a five-year field study would capture most of the inter-annual variability.

  18. Hurricane Sandy science plan: coastal impact assessments

    USGS Publications Warehouse

    Stronko, Jakob M.

    2013-01-01

    Hurricane Sandy devastated some of the most heavily populated eastern coastal areas of the Nation. With a storm surge peaking at more than 19 feet, the powerful landscape-altering destruction of Hurricane Sandy is a stark reminder of why the Nation must become more resilient to coastal hazards. In response to this natural disaster, the U.S. Geological Survey (USGS) received a total of $41.2 million in supplemental appropriations from the Department of the Interior (DOI) to support response, recovery, and rebuilding efforts. These funds support a science plan that will provide critical scientific information necessary to inform management decisions for recovery of coastal communities, and aid in preparation for future natural hazards. This science plan is designed to coordinate continuing USGS activities with stakeholders and other agencies to improve data collection and analysis that will guide recovery and restoration efforts. The science plan is split into five distinct themes: coastal topography and bathymetry, impacts to coastal beaches and barriers, impacts of storm surge, including disturbed estuarine and bay hydrology, impacts on environmental quality and persisting contaminant exposures, impacts to coastal ecosystems, habitats, and fish and wildlife. This fact sheet focuses assessing impacts to coastal beaches and barriers.

  19. Quantifying factors limiting aerobic degradation during aerobic bioreactor landfilling.

    PubMed

    Yazdani, Ramin; Mostafid, M Erfan; Han, Byunghyun; Imhoff, Paul T; Chiu, Pei; Augenstein, Don; Kayhanian, Masoud; Tchobanoglous, George

    2010-08-15

    A bioreactor landfill cell at Yolo County, California was operated aerobically for six months to quantify the extent of aerobic degradation and mechanisms limiting aerobic activity during air injection and liquid addition. The portion of the solid waste degraded anaerobically was estimated and tracked through time. From an analysis of in situ aerobic respiration and gas tracer data, it was found that a large fraction of the gas-filled pore space was in immobile zones where it was difficult to maintain aerobic conditions, even at relatively moderate landfill cell-average moisture contents of 33-36%. Even with the intentional injection of air, anaerobic activity was never less than 13%, and sometimes exceeded 65%. Analyses of gas tracer and respiration data were used to quantify rates of respiration and rates of mass transfer to immobile gas zones. The similarity of these rates indicated that waste degradation was influenced significantly by rates of oxygen transfer to immobile gas zones, which comprised 32-92% of the gas-filled pore space. Gas tracer tests might be useful for estimating the size of the mobile/immobile gas zones, rates of mass transfer between these regions, and the difficulty of degrading waste aerobically in particular waste bodies. PMID:20704218

  20. 77 FR 74341 - Establishing the Hurricane Sandy Rebuilding Task Force

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-12-14

    ... person. (Presidential Sig.) THE WHITE HOUSE, Washington, December 7, 2012. [FR Doc. 2012-30310 Filed 12... the Hurricane Sandy Rebuilding Task Force By the authority vested in me as President by the.... Hurricane Sandy made landfall on October 29, 2012, resulting in major flooding, extensive structural...

  1. Role of macrofauna on benthic oxygen consumption in sandy sediments of a high-energy tidal beach

    NASA Astrophysics Data System (ADS)

    Charbonnier, Céline; Lavesque, Nicolas; Anschutz, Pierre; Bachelet, Guy; Lecroart, Pascal

    2016-06-01

    Sandy beaches exposed to tide and waves are characterized by low abundance and diversity of benthic macrofauna, because of high-energy conditions. This is the reason why there are few studies on benthic communities living in such highly dynamic environments. It has been shown recently that tidal sandy beaches may act as biogeochemical reactors. Marine organic matter that is supplied in the sand during each flood tide is efficiently mineralized through aerobic respiration. In order to quantify the role of macrofauna in the whole beach benthic respiration, we studied the macrofauna and the pore water oxygen content of an exposed sandy beach (Truc Vert, SW of France) during four seasons in 2011. The results showed that macrofauna was characterised by a low number of species of specialized organisms such as the crustaceans Eurydice naylori and Gastrosaccus spp. and the polychaetes Ophelia bicornis and Scolelepis squamata. The distribution and abundance of macrofauna were clearly affected by exposure degree and emersion time. The combined monitoring of benthic macrofauna and pore waters chemistry allowed us to estimate (1) the macrofauna oxygen uptake, calculated with a standard allometric relationship using biomass data, and (2) the total benthic oxygen uptake, calculated from the oxygen deficit measured in pore waters. This revealed that benthic macrofauna respiration represented a variable but low (<10%) contribution to the total benthic oxygen consumption. This suggests that oxygen was mainly consumed by microbial respiration.

  2. Correlation between landscape fragmentation and sandy desertification: a case study in Horqin Sandy Land, China.

    PubMed

    Ge, Xiaodong; Dong, Kaikai; Luloff, A E; Wang, Luyao; Xiao, Jun; Wang, Shiying; Wang, Qian

    2016-01-01

    The exact roles of landscape fragmentation on sandy desertification are still not fully understood, especially with the impact of different land use types in spatial dimension. Taking patch size and shape into consideration, this paper selected the Ratio of Patch Size and the Fractal Dimension Index to establish a model that reveals the association between the area of bare sand land and the fragmentation of different land use types adjacent to bare sand land. Results indicated that (1) grass land and arable land contributed the most to landscape fragmentation processes in the regions adjacent to bare sand land during the period 1980 to 2010. Grass land occupied 54 % of the region adjacent to bare sand land in 1980. The Ratio of Patch Size of grass land decreased from 1980 to 2000 and increased after 2000. The Fractal Dimension Index of grass increased during the period 1980 to 1990 and decreased after 1990. Arable land expanded significantly during this period. The Ratio of Patch Size of arable land increased from 1980 to 1990 and decreased since 1990. The Fractal Dimension Index of arable land increased from 1990 to 2000 and decreased after 2000. (2) The Ratio of Patch Size and the Fractal Dimension Index were significantly related to the area of bare sand land. The role of landscape fragmentation was not linear to sandy desertification. There were both positive and negative effects of landscape fragmentation on sandy desertification. In 1980, the Ratio of Patch Size and the Fractal Dimension Index were negatively related to the area of bare sand land, showing that the landscape fragmentation and regularity of patches contributed to the expansion of sandy desertification. In 1990, 2000, and 2010, the Ratio of Patch Size and the Fractal Dimension Index were mostly positively related to the area of bare sand land, showing the landscape fragmentation and regularity of patches contributed to the reversion of sandy desertification in this phase. The absolute values of

  3. Correlation between landscape fragmentation and sandy desertification: a case study in Horqin Sandy Land, China.

    PubMed

    Ge, Xiaodong; Dong, Kaikai; Luloff, A E; Wang, Luyao; Xiao, Jun; Wang, Shiying; Wang, Qian

    2016-01-01

    The exact roles of landscape fragmentation on sandy desertification are still not fully understood, especially with the impact of different land use types in spatial dimension. Taking patch size and shape into consideration, this paper selected the Ratio of Patch Size and the Fractal Dimension Index to establish a model that reveals the association between the area of bare sand land and the fragmentation of different land use types adjacent to bare sand land. Results indicated that (1) grass land and arable land contributed the most to landscape fragmentation processes in the regions adjacent to bare sand land during the period 1980 to 2010. Grass land occupied 54 % of the region adjacent to bare sand land in 1980. The Ratio of Patch Size of grass land decreased from 1980 to 2000 and increased after 2000. The Fractal Dimension Index of grass increased during the period 1980 to 1990 and decreased after 1990. Arable land expanded significantly during this period. The Ratio of Patch Size of arable land increased from 1980 to 1990 and decreased since 1990. The Fractal Dimension Index of arable land increased from 1990 to 2000 and decreased after 2000. (2) The Ratio of Patch Size and the Fractal Dimension Index were significantly related to the area of bare sand land. The role of landscape fragmentation was not linear to sandy desertification. There were both positive and negative effects of landscape fragmentation on sandy desertification. In 1980, the Ratio of Patch Size and the Fractal Dimension Index were negatively related to the area of bare sand land, showing that the landscape fragmentation and regularity of patches contributed to the expansion of sandy desertification. In 1990, 2000, and 2010, the Ratio of Patch Size and the Fractal Dimension Index were mostly positively related to the area of bare sand land, showing the landscape fragmentation and regularity of patches contributed to the reversion of sandy desertification in this phase. The absolute values of

  4. Setting conservation targets for sandy beach ecosystems

    NASA Astrophysics Data System (ADS)

    Harris, Linda; Nel, Ronel; Holness, Stephen; Sink, Kerry; Schoeman, David

    2014-10-01

    Representative and adequate reserve networks are key to conserving biodiversity. This begs the question, how much of which features need to be placed in protected areas? Setting specifically-derived conservation targets for most ecosystems is common practice; however, this has never been done for sandy beaches. The aims of this paper, therefore, are to propose a methodology for setting conservation targets for sandy beach ecosystems; and to pilot the proposed method using data describing biodiversity patterns and processes from microtidal beaches in South Africa. First, a classification scheme of valued features of beaches is constructed, including: biodiversity features; unique features; and important processes. Second, methodologies for setting targets for each feature under different data-availability scenarios are described. From this framework, targets are set for features characteristic of microtidal beaches in South Africa, as follows. 1) Targets for dune vegetation types were adopted from a previous assessment, and ranged 19-100%. 2) Targets for beach morphodynamic types (habitats) were set using species-area relationships (SARs). These SARs were derived from species richness data from 142 sampling events around the South African coast (extrapolated to total theoretical species richness estimates using previously-established species-accumulation curve relationships), plotted against the area of the beach (calculated from Google Earth imagery). The species-accumulation factor (z) was 0.22, suggesting a baseline habitat target of 27% is required to protect 75% of the species. This baseline target was modified by heuristic principles, based on habitat rarity and threat status, with final values ranging 27-40%. 3) Species targets were fixed at 20%, modified using heuristic principles based on endemism, threat status, and whether or not beaches play an important role in the species' life history, with targets ranging 20-100%. 4) Targets for processes and 5

  5. Passive Microwave Observation of Soil Water Infiltration

    NASA Technical Reports Server (NTRS)

    Jackson, Thomas J.; Schmugge, Thomas J.; Rawls, Walter J.; ONeill, Peggy E.; Parlange, Marc B.

    1997-01-01

    Infiltration is a time varying process of water entry into soil. Experiments were conducted here using truck based microwave radiometers to observe small plots during and following sprinkler irrigation. Experiments were conducted on a sandy loam soil in 1994 and a silt loam in 1995. Sandy loam soils typically have higher infiltration capabilities than clays. For the sandy loam the observed brightness temperature (TB) quickly reached a nominally constant value during irrigation. When the irrigation was stopped the TB began to increase as drainage took place. The irrigation rates in 1995 with the silt loam soil exceeded the saturated conductivity of the soil. During irrigation the TB values exhibited a pattern that suggests the occurrence of coherent reflection, a rarely observed phenomena under natural conditions. These results suggested the existence of a sharp dielectric boundary (wet over dry soil) that was increasing in depth with time.

  6. MINERALIZATION OF NITROGEN FROM BROILER LITTER AS AFFECTED BY SOIL TEXTURE IN THE SOUTHEASTERN COASTAL PLAIN

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A field study was conducted during 2004-2005 to determine nitrogen (N) mineralization of broiler litter (BL) in two Coastal Plain soils of differing texture, sandy or clayey. The soils were a Tifton loamy sand (fine-loamy, siliceous, thermic, Plinthic Kandiudults) and a Greenville sandy clay loam (...

  7. Nitrogen Mineralization of Broiler Litter Applied to Southeastern Coastal Plain Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A field study was conducted to determine nitrogen (N) mineralization of broiler litter (BL) in two Coastal Plain soils of differing texture, sandy or clayey. The soils were a Tifton loamy sand (fine-loamy, siliceous, thermic, Plinthic Kandiudults) and a Greenville sandy clay loam (clayey, kaoliniti...

  8. Rediscovering community--reflections after Hurricane Sandy.

    PubMed

    See, Sharon

    2013-01-01

    Hoboken, New Jersey, is a town of 50,000 residents located across the Hudson River from New York City. Most of Hoboken's infrastructure was compromised during Hurricane Sandy as a result of flooding and power outages that rendered many businesses inoperable, including all of the pharmacies in town. Despite a focus on emergency preparedness since Hurricane Katrina and 9/11, there were no contingencies in place to facilitate and assess the medication needs of the community in the event of a natural disaster. This essay describes how the author rediscovered the meaning of community, and through working with colleagues in other health care disciplines and non-health care volunteers, provided care to patients in suboptimal circumstances.

  9. Hurricane Sandy science plan: New York

    USGS Publications Warehouse

    Ransom, Clarice N.

    2013-01-01

    Hurricane Sandy is a stark reminder of why the Nation must become more resilient to coastal hazards. More than one-half of the U.S. population lives within 50 miles of a coast, and this number is increasing. The U.S. Geological Survey (USGS) is one of the largest providers of geologic and hydrologic information in the world. Federal, State, and local partners depend on the USGS science to know how to prepare for hurricane hazards and reduce losses from future hurricanes. The USGS works closely with other bureaus within the Department of the Interior, the Federal Emergency Management Agency, the National Oceanic Atmospheric Administration, the U.S. Army Corps of Engineers, the Environmental Protection Agency, and many State and local agencies to identify their information needs before, during, and after hurricanes.

  10. Rediscovering community--reflections after Hurricane Sandy.

    PubMed

    See, Sharon

    2013-01-01

    Hoboken, New Jersey, is a town of 50,000 residents located across the Hudson River from New York City. Most of Hoboken's infrastructure was compromised during Hurricane Sandy as a result of flooding and power outages that rendered many businesses inoperable, including all of the pharmacies in town. Despite a focus on emergency preparedness since Hurricane Katrina and 9/11, there were no contingencies in place to facilitate and assess the medication needs of the community in the event of a natural disaster. This essay describes how the author rediscovered the meaning of community, and through working with colleagues in other health care disciplines and non-health care volunteers, provided care to patients in suboptimal circumstances. PMID:24218382

  11. Uranium Redistribution Due to Water Table Fluctuations in Sandy Wetland Mesocosms.

    PubMed

    Gilson, Emily R; Huang, Shan; Koster van Groos, Paul G; Scheckel, Kirk G; Qafoku, Odeta; Peacock, Aaron D; Kaplan, Daniel I; Jaffé, Peter R

    2015-10-20

    To understand better the fate and stability of immobilized uranium (U) in wetland sediments, and how intermittent dry periods affect U stability, we dosed saturated sandy wetland mesocosms planted with Scirpus acutus with low levels of uranyl acetate for 4 months before imposing a short drying and rewetting period. Concentrations of U in mesocosm effluent increased after drying and rewetting, but the cumulative amount of U released following the dry period constituted less than 1% of the total U immobilized in the soil during the 4 months prior. This low level of remobilization suggests, and XANES analyses confirm, that microbial reduction was not the primary means of U immobilization, as the U immobilized in mesocosms was primarily U(VI) rather than U(IV). Drying followed by rewetting caused a redistribution of U downward in the soil profile and to root surfaces. Although the U on roots before drying was primarily associated with minerals, the U that relocated to the roots during drying and rewetting was bound diffusely. Results show that short periods of drought conditions in a sandy wetland, which expose reduced sediments to air, may impact U distribution without causing large releases of soil-bound U to surface waters. PMID:26404564

  12. Leaching of metribuzin metabolites and the associated contamination of a sandy Danish aquifer.

    PubMed

    Kjaer, Jeanne; Olsen, Preben; Henriksen, Trine; Ullum, Marlene

    2005-11-01

    As degradation products of metribuzin have received little attention as potential groundwater contaminants, we evaluated leaching of metribuzin and its primary metabolites desaminometribuzin (DA), desaminodiketometribuzin (DADK), and diketometribuzin (DK) at a sandy test site in Denmark. Soil water and groundwater were sampled monthly over a four-year period. Leaching of metribuzin and DA was negligible. DK and DADK leached from the root zone (1 meter below ground surface (mbgs)) in average concentrations considerably exceeding the EU limit value for drinking water (0.1 microg/L). Both metabolites appear to be relatively stable and persisted in soil water and groundwater several years after application. Past application of metribuzin at the site had contaminated the groundwater with both DK and DADK, which were detected in 99% and 48%, respectively, of the groundwater samples analyzed. Except for three of the groundwater samples, the DADK concentration never exceeded the EU limit value. In contrast, the annual concentration of DK exceeded 0.1 microg/L at 90% of the screens analyzed. The present findings suggest that as the degradation products of metribuzin can leach through sandy soil in high concentrations, they could potentially contaminate the groundwater. In view of this risk DK and DADK should both be included in monitoring programs and their ecotoxicological effects should be further investigated.

  13. Fate of trace organic compounds during vadose zone soil treatment in an onsite wastewater system

    USGS Publications Warehouse

    Conn, K.E.; Siegrist, R.L.; Barber, L.B.; Meyer, M.T.

    2010-01-01

    During onsite wastewater treatment, trace organic compounds are often present in the effluents applied to subsurface soils for advanced treatment during vadose zone percolation and groundwater recharge. The fate of the endocrine-disrupting surfactant metabolites 4-nonylphenol (NP), 4-nonylphenolmonoethoxylate (NP1EO), and 4-nonylphenolmonoethoxycarboxylate (NP1EC), metal-chelating agents ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA), antimicrobial agent triclosan, stimulant caffeine, and antibiotic sulfamethoxazole during transport through an unsaturated sandy loam soil was studied at a field-scale test site. To assess the effects of effluent quality and hydraulic loading rate (HLR) on compound fate in the soil profile, two effluents (septic tank or textile biofilter) were applied at two design HLRs (2 or 8 cm/d). Chemical concentrations were determined in the two effluents and soil pore water at 60, 120, and 240 cm below the soil infiltrative surface. Concentrations of trace organic compounds in septic tank effluent were reduced by more than 90% during transport through 240 cm (often within 60 cm) of soil, likely due to sorption and biotransformation. However, the concentration of NP increased with depth in the shallow soil profile. Additional treatment of anaerobic septic tank effluent with an aerobic textile biofilter reduced effluent concentrations of many compounds, but generally did not affect any changes in pore water concentrations. The soil profile receiving septic tank effluent (vs. textile biofilter effluent) generally had greater percent removal efficiencies. EDTA, NP, NP1EC, and sulfamethoxazole were measured in soil pore water, indicating the ability of some trace organic compounds to reach shallow groundwater. Risk is highly dependent on the degree of further treatment in the saturated zone and the types and proximity of uses for the receiving groundwater environment. ?? 2009 SETAC.

  14. Characterization and aerobic biodegradation of selected monoterpenes

    SciTech Connect

    Misra, G.; Pavlostathis, S.G.; Li, J.; Purdue, E.M.

    1996-12-31

    Monoterpenes are biogenic chemicals and occur in abundance in nature. Large-scale industrial use of these chemicals has recently been initiated in an attempt to replace halogenated solvents and chlorofluorocarbons which have been implicated in the stratospheric depletion of ozone. This study examined four hydrocarbon monoterpenes (d-limonene, {alpha}-pinene, {gamma}-terpinene, and terpinolene) and four alcohols (arbanol, linalool, plinol, and {alpha}-terpineol). Water solubility, vapor pressure, and octanol/water partition coefficients were estimated. Aerobic biodegradability tests were conducted in batch reactors by utilizing forest soil extract and enriched cultures as inoculum. The hydrophobic nature and high volatility of the hydrocarbons restricted the investigation to relatively low aqueous concentrations. Each monoterpene was analyzed with a gas chromatograph equipped with a flame ionization detector after extraction from the aqueous phase with isooctane. Terpene mineralization was tested by monitoring liquid-phase carbon, CO{sub 2} production and biomass growth. All four hydrocarbons and two alcohols readily degraded under aerobic conditions. Plinol resisted degradation in assays using inocula from diverse sources, while arbanol degraded very slowly. The intrinsic biokinetics coefficients for the degradation of d-limonene and {alpha}-terpineol were estimated by using cultures enriched with the respective monoterpenes. Monoterpene biodegradation followed Monod kinetics.

  15. Landscape Visual Quality and Meiofauna Biodiversity on Sandy Beaches.

    PubMed

    Felix, Gabriela; Marenzi, Rosemeri C; Polette, Marcos; Netto, Sérgio A

    2016-10-01

    Sandy beaches are central economic assets, attracting more recreational users than other coastal ecosystems. However, urbanization and landscape modification can compromise both the functional integrity and the attractiveness of beach ecosystems. Our study aimed at investigating the relationship between sandy beach artificialization and the landscape perception by the users, and between sandy beach visual attractiveness and biodiversity. We conducted visual and biodiversity assessments of urbanized and semiurbanized sandy beaches in Brazil and Uruguay. We specifically examined meiofauna as an indicator of biodiversity. We hypothesized that urbanization of sandy beaches results in a higher number of landscape detractors that negatively affect user evaluation, and that lower-rated beach units support lower levels of biodiversity. We found that urbanized beach units were rated lower than semiurbanized units, indicating that visual quality was sensitive to human interventions. Our expectations regarding the relationship between landscape perception and biodiversity were only partially met; only few structural and functional descriptors of meiofauna assemblages differed among classes of visual quality. However, lower-rated beach units exhibited signs of lower environmental quality, indicated by higher oligochaete densities and significant differences in meiofauna structure. We conclude that managing sandy beaches needs to advance beyond assessment of aesthetic parameters to also include the structure and function of beach ecosystems. Use of such supporting tools for managing sandy beaches is particularly important in view of sea level rise and increasing coastal development.

  16. Landscape Visual Quality and Meiofauna Biodiversity on Sandy Beaches

    NASA Astrophysics Data System (ADS)

    Felix, Gabriela; Marenzi, Rosemeri C.; Polette, Marcos; Netto, Sérgio A.

    2016-10-01

    Sandy beaches are central economic assets, attracting more recreational users than other coastal ecosystems. However, urbanization and landscape modification can compromise both the functional integrity and the attractiveness of beach ecosystems. Our study aimed at investigating the relationship between sandy beach artificialization and the landscape perception by the users, and between sandy beach visual attractiveness and biodiversity. We conducted visual and biodiversity assessments of urbanized and semiurbanized sandy beaches in Brazil and Uruguay. We specifically examined meiofauna as an indicator of biodiversity. We hypothesized that urbanization of sandy beaches results in a higher number of landscape detractors that negatively affect user evaluation, and that lower-rated beach units support lower levels of biodiversity. We found that urbanized beach units were rated lower than semiurbanized units, indicating that visual quality was sensitive to human interventions. Our expectations regarding the relationship between landscape perception and biodiversity were only partially met; only few structural and functional descriptors of meiofauna assemblages differed among classes of visual quality. However, lower-rated beach units exhibited signs of lower environmental quality, indicated by higher oligochaete densities and significant differences in meiofauna structure. We conclude that managing sandy beaches needs to advance beyond assessment of aesthetic parameters to also include the structure and function of beach ecosystems. Use of such supporting tools for managing sandy beaches is particularly important in view of sea level rise and increasing coastal development.

  17. Landscape Visual Quality and Meiofauna Biodiversity on Sandy Beaches.

    PubMed

    Felix, Gabriela; Marenzi, Rosemeri C; Polette, Marcos; Netto, Sérgio A

    2016-10-01

    Sandy beaches are central economic assets, attracting more recreational users than other coastal ecosystems. However, urbanization and landscape modification can compromise both the functional integrity and the attractiveness of beach ecosystems. Our study aimed at investigating the relationship between sandy beach artificialization and the landscape perception by the users, and between sandy beach visual attractiveness and biodiversity. We conducted visual and biodiversity assessments of urbanized and semiurbanized sandy beaches in Brazil and Uruguay. We specifically examined meiofauna as an indicator of biodiversity. We hypothesized that urbanization of sandy beaches results in a higher number of landscape detractors that negatively affect user evaluation, and that lower-rated beach units support lower levels of biodiversity. We found that urbanized beach units were rated lower than semiurbanized units, indicating that visual quality was sensitive to human interventions. Our expectations regarding the relationship between landscape perception and biodiversity were only partially met; only few structural and functional descriptors of meiofauna assemblages differed among classes of visual quality. However, lower-rated beach units exhibited signs of lower environmental quality, indicated by higher oligochaete densities and significant differences in meiofauna structure. We conclude that managing sandy beaches needs to advance beyond assessment of aesthetic parameters to also include the structure and function of beach ecosystems. Use of such supporting tools for managing sandy beaches is particularly important in view of sea level rise and increasing coastal development. PMID:27376939

  18. Biology of Moderately Halophilic Aerobic Bacteria

    PubMed Central

    Ventosa, Antonio; Nieto, Joaquín J.; Oren, Aharon

    1998-01-01

    The moderately halophilic heterotrophic aerobic bacteria form a diverse group of microorganisms. The property of halophilism is widespread within the bacterial domain. Bacterial halophiles are abundant in environments such as salt lakes, saline soils, and salted food products. Most species keep their intracellular ionic concentrations at low levels while synthesizing or accumulating organic solutes to provide osmotic equilibrium of the cytoplasm with the surrounding medium. Complex mechanisms of adjustment of the intracellular environments and the properties of the cytoplasmic membrane enable rapid adaptation to changes in the salt concentration of the environment. Approaches to the study of genetic processes have recently been developed for several moderate halophiles, opening the way toward an understanding of haloadaptation at the molecular level. The new information obtained is also expected to contribute to the development of novel biotechnological uses for these organisms. PMID:9618450

  19. Modelling transport and degradation of de-icing chemicals in soil, assuming Monod kinetics with multiple electron-acceptors

    NASA Astrophysics Data System (ADS)

    Schotanus, D.; Meeussen, J. C. L.; van der Ploeg, M. J.; van der Zee, S. E. A. T. M.

    2012-04-01

    De-icing chemicals that contain propylene glycol are used at Oslo airport during winter time. A fraction of these chemicals is spilled on the runway and can be transported rapidly in the sandy soil in spring during snowmelt. Better insight into the chemical and physical processes that govern the fate of these chemicals in soil will help to estimate potential effects on the large unconfined aquifer in this area, and makes it possible to evaluate potential remedial actions. Micro-organisms in the soil can degrade propylene glycol, for which they need electron-acceptors. Under aerobic conditions, oxygen will be used as an electron-acceptor. From experiments, it is known that also anaerobic degradation occurs in this soil. During snowmelt, high infiltration rates can lead to locally saturated soil. In these parts, oxygen diffusion is limited and thus anaerobic conditions will occur. In these anaerobic regions, other electron-acceptors, such as manganese-oxides that are present in this soil, are used. However, frequent propylene glycol application may lead to a depletion of manganese-oxides and so to increased persistence and migration of propylene glycol in soil. To prevent this depletion and to enhance biodegradation, other electron-acceptors can be applied at the soil surface. Examples are the application of nitrate to the soil surface, and air injection. Model calculations could help to estimate required concentrations. The objectives of this study are 1) to create the reactive model, 2) to use this model to evaluate which parameters are determining leaching fluxes of propylene glycol from the soil, and 3) to evaluate the effectiveness of the different remediation strategies. Therefore, transient water flow, kinetic degradation, and redox chemistry were combined in one model. Degradation is modelled with Monod kinetics using multiple electron-acceptors. Oxygen diffusion in the gas phase, biomass growth, and oxidation and reduction of the important electron

  20. Degradation of TCE using sequential anaerobic biofilm and aerobic immobilized bed reactor

    NASA Technical Reports Server (NTRS)

    Chapatwala, Kirit D.; Babu, G. R. V.; Baresi, Larry; Trunzo, Richard M.

    1995-01-01

    Bacteria capable of degrading trichloroethylene (TCE) were isolated from contaminated wastewaters and soil sites. The aerobic cultures were identified as Pseudomonas aeruginosa (four species) and Pseudomonas fluorescens. The optimal conditions for the growth of aerobic cultures were determined. The minimal inhibitory concentration values of TCE for Pseudomonas sps. were also determined. The aerobic cells were immobilized in calcium alginate in the form of beads. Degradation of TCE by the anaerobic and dichloroethylene (DCE) by aerobic cultures was studied using dual reactors - anaerobic biofilm and aerobic immobilized bed reactor. The minimal mineral salt (MMS) medium saturated with TCE was pumped at the rate of 1 ml per hour into the anaerobic reactor. The MMS medium saturated with DCE and supplemented with xylenes and toluene (3 ppm each) was pumped at the rate of 1 ml per hour into the fluidized air-uplift-type reactor containing the immobilized aerobic cells. The concentrations of TCE and DCE and the metabolites formed during their degradation by the anaerobic and aerobic cultures were monitored by GC. The preliminary study suggests that the anaerobic and aerobic cultures of our isolates can degrade TCE and DCE.

  1. Degradation of TCE using sequential anaerobic biofilm and aerobic immobilized bed reactor

    NASA Astrophysics Data System (ADS)

    Chapatwala, Kirit D.; Babu, G. R. V.; Baresi, Larry; Trunzo, Richard M.

    1995-03-01

    Bacteria capable of degrading trichloroethylene (TCE) were isolated from contaminated wastewaters and soil sites. The aerobic cultures were identified as Pseudomonas aeruginosa (four species) and Pseudomonas fluorescens. The optimal conditions for the growth of aerobic cultures were determined. The minimal inhibitory concentration values of TCE for Pseudomonas sps. were also determined. The aerobic cells were immobilized in calcium alginate in the form of beads. Degradation of TCE by the anaerobic and dichloroethylene (DCE) by aerobic cultures was studied using dual reactors - anaerobic biofilm and aerobic immobilized bed reactor. The minimal mineral salt (MMS) medium saturated with TCE was pumped at the rate of 1 ml per hour into the anaerobic reactor. The MMS medium saturated with DCE and supplemented with xylenes and toluene (3 ppm each) was pumped at the rate of 1 ml per hour into the fluidized air-uplift-type reactor containing the immobilized aerobic cells. The concentrations of TCE and DCE and the metabolites formed during their degradation by the anaerobic and aerobic cultures were monitored by GC. The preliminary study suggests that the anaerobic and aerobic cultures of our isolates can degrade TCE and DCE.

  2. [Effects of desertification on C and N storages in grassland ecosystem on Horqin sandy land].

    PubMed

    Zhao, Ha-lin; Li, Yu-qiang; Zhou, Rui-lian

    2007-11-01

    Sandy grassland is widespread in northern China, where desertification is very common because of overgrazing and estrepement. However, little is known about the effects of desertification on grassland C and N storages in this region. A field survey was conducted on Horqin sandy grassland, and desertification gradients were established to evaluate the effects of desertification on C and N storages in soil, plant, and litter. The results showed that desertification had deep effects on the contents and storages of grassland C and N. The C and N contents and storages in the grassland decreased significantly with increasing desertification degree. Comparing with those in un-desertified grassland, the C and N contents in lightly, moderately, heavily, and severely desertified grasslands decreased by 56.06% and 48.72%, 78.43% and 74.36%, 88.95% and 84.62%, and 91.64% and 84.62% in 0-100 cm soil layer, and by 8.61% and 6.43%, 0.05% and 25.71%, 2.58% and 27.14%, and 8. 61% and 27. 86% in plant components, respectively. Relevantly, the C and N storages decreased by 50.95% and 43.38%, 75.19% and 71.04%, 86.76% and 81.48%, and 91.17% and 83.17% in plant underground components in 0-100 cm soil layer, and by 25.08% and 27.62%, 30.90% and 46.55%, 73.84% and 80.62%, and 90.89% and 87.31% in plant aboveground components, respectively. In 2000, the total area of desertified grassland in Horqin sandy land was 30152. 7 km2, and the C and N loss via desertification reached up to 107.53 and 9.97 Mt, respectively. Correlation analysis indicated that the decrease of soil C and N contents was mainly come from the decreased soil fine particles caused by wind erosion in the process of desertification, and the degradation of soil texture- and nutrient status led finally to the rapid decrease of C and N storages in plant biomass and litter. PMID:18260440

  3. Kinetics of the biodegradation pathway of endosulfan in the aerobic and anaerobic environments.

    PubMed

    Tiwari, Manoj K; Guha, Saumyen

    2013-09-01

    The enriched mixed culture aerobic and anaerobic bacteria from agricultural soils were used to study the degradation of endosulfan (ES) in aqueous and soil slurry environments. The extent of biodegradation was ∼95% in aqueous and ∼65% in soil slurry during 15 d in aerobic studies and, ∼80% in aqueous and ∼60% in soil slurry during 60 d in anaerobic studies. The pathways of aerobic and anaerobic degradation of ES were modeled using combination of Monod no growth model and first order kinetics. The rate of biodegradation of β-isomer was faster compared to α-isomer. Conversion of ES to endosulfan sulfate (ESS) and endosulfan diol (ESD) were the rate limiting steps in aerobic medium and, the hydrolysis of ES to ESD was the rate limiting step in anaerobic medium. The mass balance indicated further degradation of endosulfan ether (ESE) and endosulfan lactone (ESL), but no end-products were identified. In the soil slurries, the rates of degradation of sorbed contaminants were slower. As a result, net rate of degradation reduced, increasing the persistence of the compounds. The soil phase degradation rate of β-isomer was slowed down more compared with α-isomer, which was attributed to its higher partition coefficient on the soil.

  4. GOES-13 Sees Life and Death of Hurricane Sandy

    NASA Video Gallery

    This animation of satellite imagery shows the life of Hurricane Sandy from its development in the Caribbean Sea on Oct. 21, through its track up the U.S. East coast and landfall. The animation cont...

  5. On the Impact Angle of Hurricane Sandy's New Jersey Landfall

    NASA Technical Reports Server (NTRS)

    Hall, Timothy M.; Sobel, Adam H.

    2013-01-01

    Hurricane Sandy's track crossed the New Jersey coastline at an angle closer to perpendicular than any previous hurricane in the historic record, one of the factors contributing to recordsetting peak-water levels in parts of New Jersey and New York. To estimate the occurrence rate of Sandy-like tracks, we use a stochastic model built on historical hurricane data from the entire North Atlantic to generate a large sample of synthetic hurricanes. From this synthetic set we calculate that under long-term average climate conditions, a hurricane of Sandy's intensity or greater (category 1+) makes NJ landfall at an angle at least as close to perpendicular as Sandy's at an average annual rate of 0.0014 yr-1 (95% confidence range 0.0007 to 0.0023); i.e., a return period of 714 years (95% confidence range 435 to 1429).

  6. Model projections of atmospheric steering of Sandy-like superstorms.

    PubMed

    Barnes, Elizabeth A; Polvani, Lorenzo M; Sobel, Adam H

    2013-09-17

    Superstorm Sandy ravaged the eastern seaboard of the United States, costing a great number of lives and billions of dollars in damage. Whether events like Sandy will become more frequent as anthropogenic greenhouse gases continue to increase remains an open and complex question. Here we consider whether the persistent large-scale atmospheric patterns that steered Sandy onto the coast will become more frequent in the coming decades. Using the Coupled Model Intercomparison Project, phase 5 multimodel ensemble, we demonstrate that climate models consistently project a decrease in the frequency and persistence of the westward flow that led to Sandy's unprecedented track, implying that future atmospheric conditions are less likely than at present to propel storms westward into the coast.

  7. Die aerobe Glykolyse der Tumorzelle

    NASA Astrophysics Data System (ADS)

    Schneider, Friedhelm

    1981-01-01

    A high aerobic glycolysis (aerobic lactate production) is the most significant feature of the energy metabolism of rapidly growing tumor cells. Several mechanisms, which may be different in different cell lines, seem to be involved in this characteristic of energy metabolism of the tumor cell. Changes in the cell membrane leading to increased uptake and utilization of glucose, a high level of fetal types of isoenzymes, a decreased number of mitochondria and a reduced capacity to metabolize pyruvate are some factors which must be taken into consideration. It is not possible to favour one of them at the present time.

  8. Comparative study of microflora in Rhizospheric soils of Argania spinosa and Acacia raddiana of the arid zone from Oued El Ma (Tindouf)

    NASA Astrophysics Data System (ADS)

    Tissouras, Fatiha; Habib, Semira; Missoum, Malika; Louacini, Braim Kamel

    2016-04-01

    Desert soils occupy a large area in Algeria (80Moreover, exploitation of the Saharan soil microorganisms has several interests and especially in maintaining the ecological equilibrium of ecosystems. Unfortunately, few of microbiological studies have been conducted so far about the Saharan soil Algerian, with the exception of some work done on the desert soils in the region of Beni Ounif. This work falls within the framework of Project CNEPRU F02320100009. The study focuses on an evaluation of the main germs rhizosphere soils from Argania spinosa and Acacia raddiana of the region of Oued El-ma (wilaya of Tindouf), located in southwest Algeria, followed by physicochemical analysis of some parameters (soil texture, pH, moisture content, organic matter). The results reveal that both rhizosphere soils have a sandy silt texture of alkali pH, with very low water content slightly different. Organic material of the rate varies from 0.2 to 1The type of vegetation influences positively the quantity and the dynamics of microbial population. Indeed, the two soils have an interesting microbial diversity, with densities of azotobacters, fungi, aerobic bacteria and actinomycetes are very high, followed germs ammonifiants, nitrifying and denitrifying. In the presence of Argania spinosa the microbial growth is most important (6.53 × 107 germs /g soil), compared with Acacia raddiana (3.13 × 107 germs /g). This shows the stimulating effect of the vegetation on the increase in the rate of these microorganisms in the soil. Well as the strong Fitness of adaptation the microbial biomass to drought. Keywords: Argania spinoza; Acacia raddiana; rhizospheric soil; microbiology evaluation.

  9. Diesel and silica monitoring at two sites following hurricane sandy.

    PubMed

    Freund, Alice; Zuckerman, Norman; Luo, Honghong; Hsu, Hsiao-Hsien; Lucchini, Roberto

    2014-01-01

    Following Hurricane Sandy, which hit New York City and New Jersey in October 2012, industrial hygienists from the Mount Sinai and Belleview/New York University occupational medicine clinics conducted monitoring for diesel exhaust and silica in lower Manhattan and Rockaway Peninsula. Average daytime elemental carbon levels at three stations in lower Manhattan on December 4, 2012, ranged from 9 to18 μg/m(3). Sub-micron particle counts at various times on the same day were over 200,000 particles per cubic centimeter on many streets in lower Manhattan. In Rockaway Peninsula on December 12, 2012, all average daytime elemental carbon levels were below a detection limit of approximately 7 μg/m(3). The average daytime crystalline silica dust concentration was below detection at two sites on Rockaway Peninsula, and was 0.015 mg/m(3) quartz where sand was being replaced on the beach. The daily average levels of elemental carbon and airborne particulates that we measured are in the range of levels that have been found to cause respiratory effects in sensitive subpopulations like asthmatic patients after 2 hr of exposure. Control of exposure to diesel exhaust must be considered following natural disasters where diesel-powered equipment is used in cleanup and recovery. Although peak silica exposures were not likely captured in this study, but were reported by a government agency to have exceeded recommended guidelines for at least one cleanup worker, we recommend further study of silica exposures when debris removal operations or traffic create visible levels of suspended dust from soil or sand.

  10. The Transition from Aerobic to Anaerobic Metabolism.

    ERIC Educational Resources Information Center

    Skinner, James S.; McLellan, Thomas H.

    1980-01-01

    The transition from aerobic to anaerobic metabolism is discussed. More research is needed on different kinds of athletes and athletic activities and how they may affect aerobic and anaerobic metabolisms. (CJ)

  11. Soil microbial activities beneath Stipa tenacissima L. and in surrounding bare soil

    NASA Astrophysics Data System (ADS)

    Novosadová, I.; Ruiz Sinoga, J. D.; Záhora, J.; Fišerová, H.

    2010-05-01

    Open steppes dominated by Stipa tenacissima L. constitute one of the most representative ecosystems of the semi-arid zones of Eastern Mediterranean Basin (Iberian Peninsula, North of Africa). These steppes show a higher degree of variability in composition and structure. Ecosystem functioning is strongly related to the spatial pattern of grass tussocks. Soils beneath S. tenacissima grass show higher fertility and improved microclimatic conditions, favouring the formation of "resource islands" (Maestre et al., 2007). On the other hand in "resource islands" and in surrounding bare soil exists the belowground zone of influence. The competition for water and resources between plants and microorganisms is strong and mediated trough an enormous variety of exudates and resource depletion intended to regulate soil microbial communities in the rhizosphere, control herbivory, encourage beneficial symbioses, and change chemical and physical properties in soil (Pugnaire et Armas, 2008). Secondary compounds and allelopathy restrict other species growth and contribute to patchy plant distribution. Active root segregation affects not only neighbourś growth but also soil microbial activities. The objective of this study was to assess the effect of Stipa tenacissima on the key soil microbial activities under controlled incubation conditions (basal and potential respiration; net nitrogen mineralization). The experimental plots were located in the province Almería in Sierra de los Filabres Mountains near the village Gérgal (southeast Spain) in the small catchment which is situated between 1090 - 1165 m a.s.l. The area with extent of 82 000 m2 is affected by soil degradation. The climate is semiarid Mediterranean. The mean annual rainfall is of about 240 mm mostly concentrated in autumn and spring. The mean annual temperature is 13.9° C. The studied soil has a loam to sandy clay texture and is classified as Lithosol (FAO-ISRIC and ISSS, 1998). The vegetation of these areas is an

  12. The medically important aerobic actinomycetes: epidemiology and microbiology.

    PubMed Central

    McNeil, M M; Brown, J M

    1994-01-01

    The aerobic actinomycetes are soil-inhabiting microorganisms that occur worldwide. In 1888, Nocard first recognized the pathogenic potential of this group of microorganisms. Since then, several aerobic actinomycetes have been a major source of interest for the commercial drug industry and have proved to be extremely useful microorganisms for producing novel antimicrobial agents. They have also been well known as potential veterinary pathogens affecting many different animal species. The medically important aerobic actinomycetes may cause significant morbidity and mortality, in particular in highly susceptible severely immunocompromised patients, including transplant recipients and patients infected with human immunodeficiency virus. However, the diagnosis of these infections may be difficult, and effective antimicrobial therapy may be complicated by antimicrobial resistance. The taxonomy of these microorganisms has been problematic. In recent revisions of their classification, new pathogenic species have been recognized. The development of additional and more reliable diagnostic tests and of a standardized method for antimicrobial susceptibility testing and the application of molecular techniques for the diagnosis and subtyping of these microorganisms are needed to better diagnose and treat infected patients and to identify effective control measures for these unusual pathogens. We review the epidemiology and microbiology of the major medically important aerobic actinomycetes. Images PMID:7923055

  13. Jatropha curcas L. Root Structure and Growth in Diverse Soils

    PubMed Central

    Valdés-Rodríguez, Ofelia Andrea; Sánchez-Sánchez, Odilón; Pérez-Vázquez, Arturo; Caplan, Joshua S.; Danjon, Frédéric

    2013-01-01

    Unlike most biofuel species, Jatropha curcas has promise for use in marginal lands, but it may serve an additional role by stabilizing soils. We evaluated the growth and structural responsiveness of young J. curcas plants to diverse soil conditions. Soils included a sand, a sandy-loam, and a clay-loam from eastern Mexico. Growth and structural parameters were analyzed for shoots and roots, although the focus was the plasticity of the primary root system architecture (the taproot and four lateral roots). The sandy soil reduced the growth of both shoot and root systems significantly more than sandy-loam or clay-loam soils; there was particularly high plasticity in root and shoot thickness, as well as shoot length. However, the architecture of the primary root system did not vary with soil type; the departure of the primary root system from an index of perfect symmetry was 14 ± 5% (mean ± standard deviation). Although J. curcas developed more extensively in the sandy-loam and clay-loam soils than in sandy soil, it maintained a consistent root to shoot ratio and root system architecture across all types of soil. This strong genetic determination would make the species useful for soil stabilization purposes, even while being cultivated primarily for seed oil. PMID:23844412

  14. Termite infestation associated with type of soil in pulau pinang, malaysia (isoptera: rhinotermitidae).

    PubMed

    Majid, Abdul Hafiz Ab; Ahmad, Abu Hassan

    2013-12-01

    Nine soil samples from nine buildings infested with Coptotermes gestroi in Pulau Pinang, Malaysia, were tested for the type of soil texture. The soil texture analysis procedures used the hydrometer method. Four of nine buildings (44%) yielded loamy sand-type soil, whereas five of nine buildings (56%) contained sandy loam-type soil. PMID:24575252

  15. INFLUENCE OF AN ORGANIC WASTE USED AS SOIL AMENDMENT ON TRIAZINE HERBICIDE SORPTION AND AVAILABILITY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this work we have studied the influence of an organic waste generated in the olive oil mill process, used as soil amendment, on atrazine and terbuthylazine sorption and availability in soil. The soils studied were two sandy soils with different origin, Spain and Minnesota and the effect of soil a...

  16. Termite infestation associated with type of soil in pulau pinang, malaysia (isoptera: rhinotermitidae).

    PubMed

    Majid, Abdul Hafiz Ab; Ahmad, Abu Hassan

    2013-12-01

    Nine soil samples from nine buildings infested with Coptotermes gestroi in Pulau Pinang, Malaysia, were tested for the type of soil texture. The soil texture analysis procedures used the hydrometer method. Four of nine buildings (44%) yielded loamy sand-type soil, whereas five of nine buildings (56%) contained sandy loam-type soil.

  17. Effect of moisture and compost on fate of azoxystrobin in soils.

    PubMed

    Singh, Neera; Singh, Shashi B

    2010-10-01

    The effect of compost-amendment and moisture status on the persistence of azoxystrobin [methyl (E)-2-{2-(6-(2-cyanophenoxy) pyrimidin-4-yloxy) phenyl}-3-methoxyacrylate], a strobilurin fungicide, in two rice-growing soils was studied. Azoxystrobin is more sorbed in the silt loam (K f – 4.66) soil than the sandy loam (K f – 2.98) soil. Compost-amendment at 5 % levels further enhanced the azoxystrobin sorption and the respective Kf values in silt loam and sandy loam soils were 8.48 and 7.6. Azoxystrobin was more persistent in the sandy loam soil than the silt loam soil. The half–life values of azoxystrobin in nonflooded and flooded silt loam soil were 54.7 and 46.3 days, respectively. The corresponding half–life values in the sandy loam soils were 64 and 62.7 days, respectively. Compost application enhanced persistence of azoxystrobin in the silt loam soil under both moisture regimes and half-life values in non–flooded and flooded soils were 115.7 and 52.8 days, respectively. However, compost enhanced azoxystrobin degradation in the sandy loam soil and half-life values were 59 (nonflooded) and 54.7 days (flooded). The study indicates that compost amendment enhanced azoxystrobin sorption in the soils. Azoxystrobin is more persistent in non-flooded soils than the flooded soils. Compost applications to soils had mixed effect on the azoxystrobin degradation.

  18. Membrane thickening aerobic digestion processes.

    PubMed

    Woo, Bryen

    2014-01-01

    Sludge management accounts for approximately 60% of the total wastewater treatment plant expenditure and laws for sludge disposal are becoming increasingly stringent, therefore much consideration is required when designing a solids handling process. A membrane thickening aerobic digestion process integrates a controlled aerobic digestion process with pre-thickening waste activated sludge using membrane technology. This process typically features an anoxic tank, an aerated membrane thickener operating in loop with a first-stage digester followed by second-stage digestion. Membrane thickening aerobic digestion processes can handle sludge from any liquid treatment process and is best for facilities obligated to meet low total phosphorus and nitrogen discharge limits. Membrane thickening aerobic digestion processes offer many advantages including: producing a reusable quality permeate with minimal levels of total phosphorus and nitrogen that can be recycled to the head works of a plant, protecting the performance of a biological nutrient removal liquid treatment process without requiring chemical addition, providing reliable thickening up to 4% solids concentration without the use of polymers or attention to decanting, increasing sludge storage capacities in existing tanks, minimizing the footprint of new tanks, reducing disposal costs, and providing Class B stabilization.

  19. Arthritis and Aerobic Exercise: A Review.

    ERIC Educational Resources Information Center

    Ike, Robert W.; And Others

    1989-01-01

    Arthritic patients who regularly do aerobic exercise make significant gains in aerobic and functional status, and in subjective areas like pain tolerance and mood. Still, they are often advised to curtail physical activity. Guidelines are presented for physicians prescribing aerobic exercise. An exercise tolerance test is recommended. (SM)

  20. Runoff and leachate losses of phosphorus in a sandy Spodosol amended with biosolids.

    PubMed

    Alleoni, Luis R F; Brinton, Scott R; O'Connor, George A

    2008-01-01

    Florida Spodosols are sandy, inherently low in Fe- and Al-based minerals, and sorb phosphorus (P) poorly. We evaluated runoff and leachate P losses from a typical Florida Spodosol amended with biosolids and triple superphosphate (TSP). Phosphorus losses were evaluated with traditional indoor rainfall simulations but used a double-deck box arrangement that allowed leaching and runoff to be determined simultaneously. Biosolids (Lakeland, OCUD, Milorganite, and Disney) represented contrasting values of total P, percent water-extractable P (PWEP), and percentage of solids. All P sources were surface applied at 224 kg P ha(-1), representing a soil P rate typical of N-based biosolids application. All biosolids-P sources lost less P than TSP, and leachate-P losses generally dominated. For Lakeland-amended soil, bioavailable P (BAP) was mainly lost by runoff (81% of total BAP losses). This behavior was due to surface sealing and drying after application of the slurry (31 g kg(-1) solids) material. For all other P sources, BAP losses in leachate were much greater than in runoff, representing 94% of total BAP losses for TSP, 80% for Milorganite, 72% for Disney, and 69% for OCUD treatments. Phosphorus leaching can be extreme and represents a great concern in many coarse-textured Florida Spodosols and other coastal plain soils with low P-sorption capacities. The PWEP values of P sources were significantly correlated with total P and BAP losses in runoff and leachate. The PWEP of a source can serve as a good indicator of potential P loss when amended to sandy soils with low P-retention capacities. PMID:18178899