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Sample records for landfill cover soils

  1. Vegetative soil covers for hazardous waste landfills

    NASA Astrophysics Data System (ADS)

    Peace, Jerry L.

    Shallow land burial has been the preferred method for disposing of municipal and hazardous wastes in the United States because it is the simplest, cheapest, and most cost-effective method of disposal. Arid and semiarid regions of the western United States have received considerable attention over the past two decades in reference to hazardous, radioactive, and mixed waste disposal. Disposal is based upon the premise that low mean annual precipitation, high evapotranspiration, and low or negligible recharge, favor waste isolation from the environment for long periods of time. The objective of this study is to demonstrate that containment of municipal and hazardous wastes in arid and semiarid environments can be accomplished effectively without traditional, synthetic materials and complex, multi-layer systems. This research demonstrates that closure covers utilizing natural soils and native vegetation i.e., vegetative soil covers, will meet the technical equivalency criteria prescribed by the U.S. Environmental Protection Agency for hazardous waste landfills. Vegetative soil cover design combines layers of natural soil, native plant species, and climatic conditions to form a sustainable, functioning ecosystem that maintains the natural water balance. In this study, percolation through a natural analogue and an engineered cover is simulated using the one-dimensional, numerical code UNSAT-H. UNSAT-H is a Richards' equation-based model that simulates soil water infiltration, unsaturated flow, redistribution, evaporation, plant transpiration, and deep percolation. This study incorporates conservative, site-specific soil hydraulic and vegetation parameters. Historical meteorological data from 1919 to 1996 are used to simulate percolation through the natural analogue and an engineered cover, with and without vegetation. This study indicates that a 1 m (3 ft) cover is the minimum design thickness necessary to meet the U.S. Environmental Protection Agency-prescribed technical equivalency criteria of 31.5 mm/year and 1 x 10-7 cm/second for net annual percolation and average flux, respectively. Increasing cover thickness to 1.2 m (4 ft) or 1.5 m (5 ft) results in limited additional improvement in cover performance. Under historical climatic conditions, net annual percolation and average flux through a 1 m (3 ft) cover is directed upward at 0.28 mm/year and 9.03 x 10-10 cm/second, respectively, for a soil cover with vegetation.

  2. Limits and dynamics of methane oxidation in landfill cover soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to understand the limits and dynamics of methane (CH4) oxidation in landfill cover soils, we investigated CH4 oxidation in daily, intermediate, and final cover soils from two California landfills as a function of temperature, soil moisture and CO2 concentration. The results indicate a signi...

  3. Landfill final covers and soil loss from water erosion

    SciTech Connect

    Hotchkiss, T.R.

    1995-12-31

    Federal Subtitle D rules require that landfill final covers be designed so as to {open_quotes}minimize erosion{close_quotes} and {open_quotes}be capable of sustaining native plant growth.{close_quotes} The Universal Soil Loss Equation (USLE) has been recommended by the EPA as the most appropriate means for evaluating the suitability of landfill final cover designs with regard to soil loss from water erosion. Since the introduction of the original USLE, two predictive tools have been introduced that are more appropriate for determining soil loss from water erosion. The Revised Universal Soil Loss Equation (RUSLE) model, the intermediate product of erosion research since the development of the original USLE, and the Water Erosion Prediction Program (WEPP) are presented. These models are improved estimating tools that better account for landfill final cover design variables such as slope length, steepness, and non-agricultural cropping and management scenarios than the outdated USLE. The regulatory premise for requiring erosion design and erosion control planning for landfill final cover systems and their practical implementation is also discussed.

  4. Effects of earthworm cast and powdered activated carbon on methane removal capacity of landfill cover soils.

    PubMed

    Park, Soyoung; Lee, Incheol; Cho, Changhwan; Sung, Kijune

    2008-01-01

    Landfill gases could be vented through a layer of landfill cover soil that could serve as a biofilter to oxidize methane to carbon dioxide and water. Properly managed landfill cover soil layers may reduce atmospheric CH4 emissions from landfills. In the present study, the effects of earthworm cast and powdered activated carbon (PAC) on the CH4 removal capacity of the landfill cover soil was investigated. For this purpose, column and batch tests were conducted using three different materials: typical landfill cover soil, landfill cover soil amended with earthworm cast, and landfill cover soil amended with PAC. The maximum CH4 removal rate of the columns filled with landfill cover soil amended with earthworm cast was 14.6mol m(-2)d(-1), whereas that of the columns filled with typical landfill cover soil was 7.4mol m(-2)d(-1). This result shows that amendment with earthworm cast could stimulate the CH4-oxidizing capacity of landfill cover soil. The CH4 removal rate of the columns filled with landfill cover soil amended with PAC also showed the same removal rate, but the vertical profile of gas concentrations in the columns and the methanotrophic population measured in the microbial assay suggested that the decrease of CH4 concentration in the columns is mainly due to sorption. Based on the results from this study, amendment of landfill cover soil with earthworm cast and PAC could improve its CH4 removal capacity and thus achieve a major reduction in atmospheric CH4 emission as compared with the same landfill cover soil without any amendment. PMID:17764722

  5. Rapid methane oxidation in a landfill cover soil.

    PubMed

    Whalen, S C; Reeburgh, W S; Sandbeck, K A

    1990-11-01

    Methane oxidation rates observed in a topsoil covering a retired landfill are the highest reported (45 g m day) for any environment. This microbial community had the capacity to rapidly oxidize CH(4) at concentrations ranging from <1 ppm (microliters per liter) (first-order rate constant [k] = -0.54 h) to >10 ppm (k = -2.37 h). The physiological characteristics of a methanotroph isolated from the soil (characteristics determined in aqueous medium) and the natural population, however, were similar to those of other natural populations and cultures: the Q(10) and optimum temperature were 1.9 and 31 degrees C, respectively, the apparent half-saturation constant was 2.5 to 9.3 muM, and 19 to 69% of oxidized CH(4) was assimilated into biomass. The CH(4) oxidation rate of this soil under waterlogged (41% [wt/vol] H(2)O) conditions, 6.1 mg liter day, was near rates reported for lake sediment and much lower than the rate of 116 mg liter day in the same soil under moist (11% H(2)O) conditions. Since there are no large physiological differences between this microbial community and other CH(4) oxidizers, we attribute the high CH(4) oxidation rate in moist soil to enhanced CH(4) transport to the microorganisms; gas-phase molecular diffusion is 10-fold faster than aqueous diffusion. These high CH(4) oxidation rates in moist soil have implications that are important in global climate change. Soil CH(4) oxidation could become a negative feedback to atmospheric CH(4) increases (and warming) in areas that are presently waterlogged but are projected to undergo a reduction in summer soil moisture. PMID:16348346

  6. Gas Transport Parameters for Landfill Cover Soils: Effects of Soil Compaction and Water Blockages

    NASA Astrophysics Data System (ADS)

    Wickramarachchi, P. N.; Hamamoto, S.; Kawamoto, K.; Nawagamuwa, U.; Komatsu, T.; Moldrup, P.

    2009-12-01

    Recently, landfill sites have been emerging in greenhouse warming scenarios as a significant source of atmospheric CH4. landfill management strategies have mainly addressed the problem of preventing groundwater contamination and reduction of leachate generation. Being one of the largest source of anthropogenic CH4 emission , the final cover system should also be designed for minimizing the biogas migration into the atmosphere or the areas surrounding the landfill. Compared to the intensive research efforts on hydraulic performances of landfill final cover soil , there are few studies about gas transport characteristics of landfill cover soils. Therefore, the effects of soil physical properties such as bulk density (i.e., compaction level), soil particle size and water blockage effects on the gas exchange in t highly compacted final cover soil are largely unknown. The gas exchange through the final cover soils is controlled by advective and diffusive gas transport. Air permeability (ka) governs the advective gas transport while the soil-gas diffusion coefficient (Dp) governs diffusive gas transport . In this study, the effects of compaction level and water blockage effects on ka and Dp for two landfill final cover soils were investigated. The disturbed soil samples were taken from landfill final covers in Japan and Sri Lanka. A compaction tests were performed for the soil samples with two different size fractions (< 35 mm and < 2.0 mm). In the compaction tests at field water content , the soil samples were repacked into soil cores (i.d. 15-cm, length 12-cm) at two different compaction levels (2700 kN/m2 and 600 kN/m2). After the compaction tests, ka and Dp were measured and then samples were saturated and subsequently drained at different soil-water matric potential (pF; pF equals to log(-?) where ? is soil-water matric potential in cm H2O) of 1.5, 2.0, 3.0, 4.1, and with air-dried (pF 6.0) and oven-dried (pF 6.9) conditions. Results showed that measured Dp values increased rather linearly with increasing soil air content (?) for both compacted and repacked samples using different size fractions and compaction levels in Japanese and Sri Lankan soils. This suggests that the gas diffusion was controlled primarily by the air-filled pore space and was less affected by the pore structure variations such as tortuosity and connectivity. On the other hand, measured ka values showed nonlinear relations with ? and were highly affected by compaction levels and water blockage effects. For the compacted soils at high energy level, peak values in ka appeared at drier conditions than optimum water contents in the compaction curves. This would be partially caused by the pore structure changes at different water conditions under compaction. Combined effects of soil compaction and water reduction will be further discussed taking pore structure characteristics derived from measured Dp and ka into account.

  7. Gas Transport Parameters for Landfill Final Cover Soil: Measurements and Model Modification by Dry Bulk Density

    NASA Astrophysics Data System (ADS)

    Wickramarachchi, P. N.; Kawamoto, K.; Hamamoto, S.; Nagamori, M.; Moldrup, P.; Komatsu, T.

    2011-12-01

    Landfill sites have been emerging in greenhouse warming scenarios as a significant source of atmospheric methane (CH4). Until recently, landfill management strategies have mainly addressed the problem of preventing groundwater contamination and reduction of leachate generation. Being one of the largest sources of anthropogenic CH4 emission, the final cover system should also be designed for minimizing the greenhouse gases migration into the atmosphere or the areas surrounding the landfill while securing the hydraulic performance. Compared to the intensive research efforts on hydraulic performances of landfill final cover soil, few studies about gas transport characteristics of landfill cover soils have been done. However, recent soil-gas studies implied that the effects of soil physical properties such as bulk density (i.e., compaction level), soil particle size are key parameters to understand landfill gaseous performance. The gas exchange through the final cover soils is controlled by advective and diffusive gas transport. Air permeability (ka) governs the advective gas transport while the soil-gas diffusion coefficient (Dp) governs diffusive gas transport. In this study, the effects of compaction level and particle size fraction effects on ka and Dp for landfill final cover soil was investigated. The disturbed soil samples were taken from landfill final cover in Japan. A compaction tests were performed for the soil samples with two different size fractions (< 35 mm and < 2.0 mm). In the compaction tests at field water content , the soil samples were repacked into soil cores (i.d. 15-cm, length 12-cm, 2120 cm3) at two different compaction levels [(MP):2700 kN/m2 and (SP):600 kN/m2]. After the compaction tests, ka and Dp were measured and then samples were saturated and subsequently drained at different soil-water matric potential of 0.98, 2.94, 9.81, 1235 kPa and with air-dried and oven-dried conditions. Results showed that measured Dp and ka values for the coarser (< 35 mm) fraction became larger than finer (< 2 mm) for the given soil-air content. Further, compaction effort was much significant for ka than Dp for both fractions. We suggest this is because of compaction effects caused to create well-aligned macropore networks that are available for gas transport through the porous material. Then, the famous predictive models, the water induced linear reduction (WLR) model for Dp and the reference point law (RPL) model for ka were modified with reference point measurements (dry conditions) and model parameters and they correlated linearly to dry bulk density values for both fractions of landfill final cover soil.

  8. Characterization of H2S removal and microbial community in landfill cover soils.

    PubMed

    Xia, Fang-Fang; Zhang, Hong-Tao; Wei, Xiao-Meng; Su, Yao; He, Ruo

    2015-12-01

    H2S is a source of odors at landfills and poses a threat to the surrounding environment and public health. In this work, compared with a usual landfill cover soil (LCS), H2S removal and biotransformation were characterized in waste biocover soil (WBS), an alternative landfill cover material. With the input of landfill gas (LFG), the gas concentrations of CH4, CO2, O2, and H2S, microbial community and activity in landfill covers changed with time. Compared with LCS, lower CH4 and H2S concentrations were detected in the WBS. The potential sulfur-oxidizing rate and sulfate-reducing rate as well as the contents of acid-volatile sulfide, SO4 (2-), and total sulfur in the WBS and LCS were all increased with the input of LFG. After exposure to LFG for 35days, the sulfur-oxidizing rate of the bottom layer of the WBS reached 82.5?molg dry weight (d.w.)(-1)?day(-1), which was 4.3-5.4 times of that of LCS. H2S-S was mainly deposited in the soil covers, while it escaped from landfills to the atmosphere. The adsorption, absorption, and biotransformation of H2S could lead to the decrease in the pH values of landfill covers; especially, in the LCS with low pH buffer capacity, the pH value of the bottom layer dropped to below 4. Pyrosequencing of 16S ribosomal RNA (rRNA) gene showed that the known sulfur-metabolizing bacteria Ochrobactrum, Paracoccus, Comamonas, Pseudomonas, and Acinetobacter dominated in the WBS and LCS. Among them, Comamonas and Acinetobacter might play an important role in the metabolism of H2S in the WBS. These findings are helpful to understand sulfur bioconversion process in landfill covers and to develop techniques for controlling odor pollution at landfills. PMID:26206130

  9. Assessment of the methane oxidation capacity of compacted soils intended for use as landfill cover materials

    SciTech Connect

    Rachor, Ingke; Gebert, Julia; Groengroeft, Alexander; Pfeiffer, Eva-Maria

    2011-05-15

    The microbial oxidation of methane in engineered cover soils is considered a potent option for the mitigation of emissions from old landfills or sites containing wastes of low methane generation rates. A laboratory column study was conducted in order to derive design criteria that enable construction of an effective methane oxidising cover from the range of soils that are available to the landfill operator. Therefore, the methane oxidation capacity of different soils was assessed under simulated landfill conditions. Five sandy potential landfill top cover materials with varying contents of silt and clay were investigated with respect to methane oxidation and corresponding soil gas composition over a period of four months. The soils were compacted to 95% of their specific proctor density, resulting in bulk densities of 1.4-1.7 g cm{sup -3}, reflecting considerably unfavourable conditions for methane oxidation due to reduced air-filled porosity. The soil water content was adjusted to field capacity, resulting in water contents ranging from 16.2 to 48.5 vol.%. The investigated inlet fluxes ranged from 25 to about 100 g CH{sub 4} m{sup -2} d{sup -1}, covering the methane load proposed to allow for complete oxidation in landfill covers under Western European climate conditions and hence being suggested as a criterion for release from aftercare. The vertical distribution of gas concentrations, methane flux balances as well as stable carbon isotope studies allowed for clear process identifications. Higher inlet fluxes led to a reduction of the aerated zone, an increase in the absolute methane oxidation rate and a decline of the relative proportion of oxidized methane. For each material, a specific maximum oxidation rate was determined, which varied between 20 and 95 g CH{sub 4} m{sup -2} d{sup -1} and which was positively correlated to the air-filled porosity of the soil. Methane oxidation efficiencies and gas profile data imply a strong link between oxidation capacity and diffusive ingress of atmospheric air. For one material with elevated levels of fine particles and high organic matter content, methane production impeded the quantification of methane oxidation potentials. Regarding the design of landfill cover layers it was concluded that the magnitude of the expected methane load, the texture and expected compaction of the cover material are key variables that need to be known. Based on these, a column study can serve as an appropriate testing system to determine the methane oxidation capacity of a soil intended as landfill cover material.

  10. Assessment of the methane oxidation capacity of compacted soils intended for use as landfill cover materials.

    PubMed

    Rachor, Ingke; Gebert, Julia; Grngrft, Alexander; Pfeiffer, Eva-Maria

    2011-05-01

    The microbial oxidation of methane in engineered cover soils is considered a potent option for the mitigation of emissions from old landfills or sites containing wastes of low methane generation rates. A laboratory column study was conducted in order to derive design criteria that enable construction of an effective methane oxidising cover from the range of soils that are available to the landfill operator. Therefore, the methane oxidation capacity of different soils was assessed under simulated landfill conditions. Five sandy potential landfill top cover materials with varying contents of silt and clay were investigated with respect to methane oxidation and corresponding soil gas composition over a period of four months. The soils were compacted to 95% of their specific proctor density, resulting in bulk densities of 1.4-1.7 g cm(-3), reflecting considerably unfavourable conditions for methane oxidation due to reduced air-filled porosity. The soil water content was adjusted to field capacity, resulting in water contents ranging from 16.2 to 48.5 vol.%. The investigated inlet fluxes ranged from 25 to about 100g CH(4)m(-2)d(-1), covering the methane load proposed to allow for complete oxidation in landfill covers under Western European climate conditions and hence being suggested as a criterion for release from aftercare. The vertical distribution of gas concentrations, methane flux balances as well as stable carbon isotope studies allowed for clear process identifications. Higher inlet fluxes led to a reduction of the aerated zone, an increase in the absolute methane oxidation rate and a decline of the relative proportion of oxidized methane. For each material, a specific maximum oxidation rate was determined, which varied between 20 and 95 g CH(4)m(-2)d(-1) and which was positively correlated to the air-filled porosity of the soil. Methane oxidation efficiencies and gas profile data imply a strong link between oxidation capacity and diffusive ingress of atmospheric air. For one material with elevated levels of fine particles and high organic matter content, methane production impeded the quantification of methane oxidation potentials. Regarding the design of landfill cover layers it was concluded that the magnitude of the expected methane load, the texture and expected compaction of the cover material are key variables that need to be known. Based on these, a column study can serve as an appropriate testing system to determine the methane oxidation capacity of a soil intended as landfill cover material. PMID:21067907

  11. Minimizing N2O fluxes from full-scale municipal solid waste landfill with properly selected cover soil.

    PubMed

    Zhang, Houhu; He, Pinjing; Shao, Liming; Qu, Xian; Lee, Duujong

    2008-01-01

    Municipal solid waste landfills emit nitrous oxide (N2O) gas. Assuming that the soil cover is the primary N2O source from landfills, this study tested, during a four-year project, the hypothesis that the proper use of chosen soils with fine texture minimizes N2O emissions. A full-scale sanitary landfill, a full-scale bioreactor landfill and a cell planted with Nerium indicum or Festuca arundinacea Schreb, at the Hangzhou Tianziling landfill in Hangzhou City were the test sites. The N2O emission rates from all test sites were considerably lower than those reported in the published reports. Specifically, the N2O emission rate was dependent on soil water content and nitrate concentrations in the cover soil. The effects of leachate recirculation and irrigation were minimal. Properly chosen cover soils applied to the landfills reduced N2O flux. PMID:18574960

  12. Strategies to Optimize Microbially-Mediated Mitigation of Greenhouse Gas Emissions from Landfill Cover Soils

    SciTech Connect

    Jeremy Semrau; Sung-Woo Lee; Jeongdae Im; Sukhwan Yoon; Michael Barcelona

    2010-09-30

    The overall objective of this project, 'Strategies to Optimize Microbially-Mediated Mitigation of Greenhouse Gas Emissions from Landfill Cover Soils' was to develop effective, efficient, and economic methodologies by which microbial production of nitrous oxide can be minimized while also maximizing microbial consumption of methane in landfill cover soils. A combination of laboratory and field site experiments found that the addition of nitrogen and phenylacetylene stimulated in situ methane oxidation while minimizing nitrous oxide production. Molecular analyses also indicated that methane-oxidizing bacteria may play a significant role in not only removing methane, but in nitrous oxide production as well, although the contribution of ammonia-oxidizing archaea to nitrous oxide production can not be excluded at this time. Future efforts to control both methane and nitrous oxide emissions from landfills as well as from other environments (e.g., agricultural soils) should consider these issues. Finally, a methanotrophic biofiltration system was designed and modeled for the promotion of methanotrophic activity in local methane 'hotspots' such as landfills. Model results as well as economic analyses of these biofilters indicate that the use of methanotrophic biofilters for controlling methane emissions is technically feasible, and provided either the costs of biofilter construction and operation are reduced or the value of CO{sub 2} credits is increased, can also be economically attractive.

  13. Can soil gas profiles be used to assess microbial CH4 oxidation in landfill covers?

    PubMed

    Gebert, Julia; Röwer, Inga Ute; Scharff, Heijo; Roncato, Camila D L; Cabral, Alexandre R

    2011-05-01

    A method is proposed to estimate CH(4) oxidation efficiency in landfill covers, biowindows or biofilters from soil gas profile data. The approach assumes that the shift in the ratio of CO(2) to CH(4) in the gas profile, compared to the ratio in the raw landfill gas, is a result of the oxidation process and thus allows the calculation of the cumulative share of CH(4) oxidized up to a particular depth. The approach was validated using mass balance data from two independent laboratory column experiments. Values corresponded well over a wide range of oxidation efficiencies from less than 10% to nearly total oxidation. An incubation experiment on 40 samples from the cover soil of an old landfill showed that the share of CO(2) from respiration falls below 10% of the total CO(2) production when the methane oxidation capacity is 3.8 μg CH(4)g(dw)(-1)h(-1) or higher, a rate that is often exceeded in landfill covers and biofilters. The method is mainly suitable in settings where the CO(2) concentrations are not significantly influenced by processes such as respiration or where CH(4) loadings and oxidation rates are high enough so that CO(2) generated from CH(4) oxidation outweighs other sources of CO(2). The latter can be expected for most biofilters, biowindows and biocovers on landfills. This simple method constitutes an inexpensive complementary tool for studies that require an estimation of the CH(4) oxidation efficiency values in methane oxidation systems, such as landfill biocovers and biowindows. PMID:21074981

  14. Quantifying methane oxidation in a landfill-cover soil by gas push-pull tests

    SciTech Connect

    Gomez, K.E. Gonzalez-Gil, G.; Lazzaro, A.; Schroth, M.H.

    2009-09-15

    Methane (CH{sub 4}) oxidation by aerobic methanotrophs in landfill-cover soils decreases emissions of landfill-produced CH{sub 4} to the atmosphere. To quantify in situ rates of CH{sub 4} oxidation we performed five gas push-pull tests (GPPTs) at each of two locations in the cover soil of the Lindenstock landfill (Liestal, Switzerland) over a 4 week period. GPPTs consist of the injection of a gas mixture containing CH{sub 4}, O{sub 2} and noble gas tracers followed by extraction from the same location. Quantification of first-order rate constants was based upon comparison of breakthrough curves of CH{sub 4} with either Ar or CH{sub 4} itself from a subsequent inactive GPPT containing acetylene as an inhibitor of CH{sub 4} oxidation. The maximum calculated first-order rate constant was 24.8 {+-} 0.8 h{sup -1} at location 1 and 18.9 {+-} 0.6 h{sup -1} at location 2. In general, location 2 had higher background CH{sub 4} concentrations in vertical profile samples than location 1. High background CH{sub 4} concentrations in the cover soil during some experiments adversely affected GPPT breakthrough curves and data interpretation. Real-time PCR verified the presence of a large population of methanotrophs at the two GPPT locations and comparison of stable carbon isotope fractionation of CH{sub 4} in an active GPPT and a subsequent inactive GPPT confirmed that microbial activity was responsible for the CH{sub 4} oxidation. The GPPT was shown to be a useful tool to reproducibly estimate in situ rates of CH{sub 4} oxidation in a landfill-cover soil when background CH{sub 4} concentrations were low.

  15. Quantifying methane oxidation in a landfill-cover soil by gas push-pull tests.

    PubMed

    Gmez, K E; Gonzalez-Gil, G; Lazzaro, A; Schroth, M H

    2009-09-01

    Methane (CH(4)) oxidation by aerobic methanotrophs in landfill-cover soils decreases emissions of landfill-produced CH(4) to the atmosphere. To quantify in situ rates of CH(4) oxidation we performed five gas push-pull tests (GPPTs) at each of two locations in the cover soil of the Lindenstock landfill (Liestal, Switzerland) over a 4 week period. GPPTs consist of the injection of a gas mixture containing CH(4), O(2) and noble gas tracers followed by extraction from the same location. Quantification of first-order rate constants was based upon comparison of breakthrough curves of CH(4) with either Ar or CH(4) itself from a subsequent inactive GPPT containing acetylene as an inhibitor of CH(4) oxidation. The maximum calculated first-order rate constant was 24.8+/-0.8 h(-1) at location 1 and 18.9+/-0.6 h(-1) at location 2. In general, location 2 had higher background CH(4) concentrations in vertical profile samples than location 1. High background CH(4) concentrations in the cover soil during some experiments adversely affected GPPT breakthrough curves and data interpretation. Real-time PCR verified the presence of a large population of methanotrophs at the two GPPT locations and comparison of stable carbon isotope fractionation of CH(4) in an active GPPT and a subsequent inactive GPPT confirmed that microbial activity was responsible for the CH(4) oxidation. The GPPT was shown to be a useful tool to reproducibly estimate in situ rates of CH(4) oxidation in a landfill-cover soil when background CH(4) concentrations were low. PMID:19525106

  16. An analytical model for estimating the reduction of methane emission through landfill cover soils by methane oxidation.

    PubMed

    Yao, Yijun; Su, Yao; Wu, Yun; Liu, Weiping; He, Ruo

    2015-01-01

    Landfill is an important source of atmospheric methane (CH4). In this study, the development and partial validation are presented for an analytical model for predicting the reduction of CH4 emission in landfill cover soils by CH4 oxidation. The model combines an analytic solution of a coupled oxygen (O2) and CH4 soil gas transport in landfill covers with a piecewise first-order aerobic biodegradation, including the influences of environmental factors such as cover soil thickness, CH4 oxidation and CH4 production rate. Comparison of soil gas concentration profiles with a soil column experiment is provided for a partial validation, and then this model is applied to predict the reduction of CH4 emission through landfill covers in several other cases. A discussion is provided to illustrate the roles of soil layer thickness, reaction rate constant for CH4 oxidation and CH4 production rate in determining CH4 emissions. The results suggest that the increase of cover soil thickness cannot always increase CH4 oxidation rates or removal efficiency, which becomes constant if the thickness of landfill cover soil is larger than a limit. PMID:25464331

  17. Above- and below-ground methane fluxes and methanotrophic activity in a landfill-cover soil

    SciTech Connect

    Schroth, M.H.; Eugster, W.; Gomez, K.E.; Gonzalez-Gil, G.; Niklaus, P.A.; Oester, P.

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer We quantify above- and below-ground CH{sub 4} fluxes in a landfill-cover soil. Black-Right-Pointing-Pointer We link methanotrophic activity to estimates of CH{sub 4} loading from the waste body. Black-Right-Pointing-Pointer Methane loading and emissions are highly variable in space and time. Black-Right-Pointing-Pointer Eddy covariance measurements yield largest estimates of CH{sub 4} emissions. Black-Right-Pointing-Pointer Potential methanotrophic activity is high at a location with substantial CH{sub 4} loading. - Abstract: Landfills are a major anthropogenic source of the greenhouse gas methane (CH{sub 4}). However, much of the CH{sub 4} produced during the anaerobic degradation of organic waste is consumed by methanotrophic microorganisms during passage through the landfill-cover soil. On a section of a closed landfill near Liestal, Switzerland, we performed experiments to compare CH{sub 4} fluxes obtained by different methods at or above the cover-soil surface with below-ground fluxes, and to link methanotrophic activity to estimates of CH{sub 4} ingress (loading) from the waste body at selected locations. Fluxes of CH{sub 4} into or out of the cover soil were quantified by eddy-covariance and static flux-chamber measurements. In addition, CH{sub 4} concentrations at the soil surface were monitored using a field-portable FID detector. Near-surface CH{sub 4} fluxes and CH{sub 4} loading were estimated from soil-gas concentration profiles in conjunction with radon measurements, and gas push-pull tests (GPPTs) were performed to quantify rates of microbial CH{sub 4} oxidation. Eddy-covariance measurements yielded by far the largest and probably most representative estimates of overall CH{sub 4} emissions from the test section (daily mean up to {approx}91,500 {mu}mol m{sup -2} d{sup -1}), whereas flux-chamber measurements and CH{sub 4} concentration profiles indicated that at the majority of locations the cover soil was a net sink for atmospheric CH{sub 4} (uptake up to -380 {mu}mol m{sup -2} d{sup -1}) during the experimental period. Methane concentration profiles also indicated strong variability in CH{sub 4} loading over short distances in the cover soil, while potential methanotrophic activity derived from GPPTs was high (v{sub max} {approx} 13 mmol L{sup -1}(soil air) h{sup -1}) at a location with substantial CH{sub 4} loading. Our results provide a basis to assess spatial and temporal variability of CH{sub 4} dynamics in the complex terrain of a landfill-cover soil.

  18. Spatial patterns of methane oxidation and methanotrophic diversity in landfill cover soils of southern China.

    PubMed

    Chi, Zi-Fang; Lu, Wen-Jing; Wang, Hong-Tao

    2015-04-01

    Aerobic CH4 oxidation is an important CH4 sink in landfills. To investigate the distribution and community diversity of methanotrophs and link with soil characteristics and operational parameters (e.g., concentrations of O2, CH4), cover soil samples were collected at different locations and depths from the Mengzi semi-aerobic landfill (SAL) in Yunnan Province of southern China. Specific PCR followed by denaturing gradient gel electrophoresis and realtime PCR were used to examine methanotrophs in the landfill cover soils. The results showed that different locations did harbor distinct methanotroph communities. Methanotrophs were more abundant in areas near the venting pipes because of the higher O2 concentrations. The depth of 20-25 cm, where the ratio of the CH4 to O2 was within the range from 1.3 to 8.6, was more conducive to the growth of CH4-oxidizing bacteria. Type II methanotrophs dominated in all samples compared with Type I methanotrophs, as evidenced by the high ratio of Type II to Type I methanotrophic copy numbers (from 1.76 to 11.60). The total copy numbers of methanotrophs detected were similar to other ecosystems, although the CH4 concentration was much higher in SAL cover soil. Methylobacter and Methylocystis were the most abundant Type I and Type II methanotrophs genera, respectively, in the Mengzi SAL. The results suggested that SALs could provide a special environment with both high concentrations of CH4 and O2 for methanotrophs, especially around the vertical venting pipes. PMID:25341468

  19. ENGINEERING BULLETIN: LANDFILL COVERS

    EPA Science Inventory

    Landfill covers are used at Superfund sites to minimize surface water infiltration and control gas migration. In many cases covers are used in conjunction with other waste treatment technologies, such as slurry walls, ground water pump-and-treat systems, and gas collection. This ...

  20. Modelling of stable isotope fractionation by methane oxidation and diffusion in landfill cover soils

    SciTech Connect

    Mahieu, Koenraad De Visscher, Alex; Vanrolleghem, Peter A.; Van Cleemput, Oswald

    2008-07-01

    A technique to measure biological methane oxidation in landfill cover soils that is gaining increased interest is the measurement of stable isotope fractionation in the methane. Usually to quantify methane oxidation, only fractionation by oxidation is taken into account. Recently it was shown that neglecting the isotope fractionation by diffusion results in underestimation of the methane oxidation. In this study a simulation model was developed that describes gas transport and methane oxidation in landfill cover soils. The model distinguishes between {sup 12}CH{sub 4}, {sup 13}CH{sub 4}, and {sup 12}CH{sub 3}D explicitly, and includes isotope fractionation by diffusion and oxidation. To evaluate the model, the simulations were compared with column experiments from previous studies. The predicted concentration profiles and isotopic profiles match the measured ones very well, with a root mean square deviation (RMSD) of 1.7 vol% in the concentration and a RMSD of 0.8 per mille in the {delta}{sup 13}C value, with {delta}{sup 13}C the relative {sup 13}C abundance as compared to an international standard. Overall, the comparison shows that a model-based isotope approach for the determination of methane oxidation efficiencies is feasible and superior to existing isotope methods.

  1. In-Situ Quantification of Methanotrophic Activity in a Landfill Cover Soil Using Gas Push-Pull Tests

    NASA Astrophysics Data System (ADS)

    Gomez, K. E.; Gonzalez-Gil, G.; Schroth, M. H.; Zeyer, J.

    2007-12-01

    Landfills are both a major anthropogenic source and a sink for the greenhouse gas CH4. Methanogenic bacteria produce CH4 during the anaerobic digestion of landfill waste, whereas, methanotrophic bacteria consume CH4 as it is transported through a landfill cover soil. Methanotrophs are thought to be ubiquitous in soils, but typically exist in large numbers at oxic/anoxic interfaces, close to anaerobic methane sources but exposed to oxygen required for metabolism. Accurate in-situ quantification of the sink strength of methanotrophs in landfill cover soils is needed for global carbon balances and for local emissions mitigation strategies. We measured in-situ CH4 concentrations at 30, 60, and 100 cm depth at 18 evenly spaced locations across a landfill cover soil. Furthermore, we performed Gas Push-Pull Tests (GPPTs) to estimate in-situ rates of methanotrophic activity in the cover soil. The GPPT is a gas-tracer test in which a gas mixture containing CH4, O2, and non-reactive tracer gases is injected (pushed) into the soil followed by extraction (pull) from the same location. Quantification of CH4 oxidation rates is based upon comparison of the breakthrough curves of CH4 and tracer gases. We present the results of a series of GPPTs conducted at two locations in the cover soil to assess the feasibility and reproducibility of this technique to quantify methanotrophic activity. Additional GPPTs were performed with a methanotrophic inhibitor in the injection gas mixture to confirm the appropriate choice of tracers to quantify CH4 oxidation. Estimated CH4 oxidation rate constants indicate that the cover soil contains a highly active methanotrophic community.

  2. Environmental factors influencing attenuation of methane and hydrochlorofluorocarbons in landfill cover soils.

    PubMed

    Scheutz, Charlotte; Kjeldsen, Peter

    2004-01-01

    The influence of different environmental factors on methane oxidation and degradation of hydrochlorofluorocarbons (HCFCs) was investigated in microcosms containing soil sampled at Skellingsted Landfill, Denmark. The soil showed a high capacity for methane oxidation resulting in a maximum oxidation rate of 104 microg CH4 g(-1) h(-1) and a low affinity of methane with a half-saturation constant of 2.0% v/v. The hydrochlorofluorocarbons HCFC-21 (dichlorofluoromethane) and HCFC-22 (chlorodifluoromethane) were rapidly oxidized and the oxidation occurred in parallel with the oxidation of methane. The maximal HCFC oxidation rates were 0.95 and 0.68 microg g(-1) h(-1) for HCFC-21 and HCFC-22, respectively. Increasing concentrations of HCFCs resulted in decreased methane oxidation rates. However, compared with typical concentrations in landfill gas, relatively high HCFC concentrations were needed to obtain a significant inhibition of methane oxidation. In general, the environmental factors studied influenced the degradation of HCFCs in almost the same way as they influenced methane oxidation. Temperature had a strong influence on the methanotrophic activity giving high Q10 values of 3.4 to 4.1 over the temperature range of 2 to 25 degrees C. Temperature optimum was around 30 degrees C; however, oxidation occurred at temperatures as low as 2 degrees C. A moisture content of 25% w/w yielded the maximum oxidation rate as it allowed good gas transport together with sufficient microbial activity. The optimum pH was around neutrality (pH = 6.5-7.5) showing that the methanotrophs were optimally adapted to the in situ pH, which was 6.9. Copper showed no inhibitory effect when added in relatively high concentrations (up to 60 mg kg(-1)), most likely due to sorption of copper ions to soil particles. At higher copper concentrations the oxidation rates decreased. The oxidation rates for methane, HCFC-21, and HCFC-22 were unaltered in ammonium-amended soil up to 14 mg kg(-1). Higher ammonium concentrations inhibited the oxidation process. The most important parameters controlling oxidation in landfill cover soil were found to be temperature, soil moisture, and methane and oxygen supply. PMID:14964360

  3. Use of stable isotopes to determine methane oxidation in landfill cover soils

    NASA Astrophysics Data System (ADS)

    Liptay, K.; Chanton, J.; Czepiel, P.; Mosher, B.

    1998-04-01

    The mean isotopic composition of CH4 emitted from six New England (United States) landfills was 13C and D enriched (-48.1 to -50.4 and -273 to -281) relative to anoxic zone landfill CH4 (mean values of -55.9 to -56.2 and -296 to -300) owing to the oxidation of methane as it was transported from the landfill to the atmosphere through the soil cap. The fraction of methane oxidized f0 during its passage through the soil cap was calculated from the degree of 13C enrichment in emitted CH4 relative to anoxic zone CH4 in conjunction with values determined for the preference of soil methane oxidizing bacteria for 12CH4 over 13CH4 (? = 1.022 0.008). Mean values for methane oxidation in six landfills were from 24 to 35% of the total flux through the soil during the warm season, depending upon how the data were grouped. Our results bracket recent estimates of methane oxidation of about 30% in the warm summer period produced using a model with the input terms of soil temperature, moisture, depth, and oxygen concentration. Because of variations in the response of methane oxidation to temperature at these New England sites, our study is consistent with the modeling results of Czepiel et al. [1996b] that the best estimate for the annual value for methane oxidation in the landfills considered is about 10%.

  4. Evaluation of soil top-cover systems to minimize infiltration into a sanitary landfill: A case study

    NASA Astrophysics Data System (ADS)

    Weeks, Olaf L.; Mansell, Robert S.; McCallister, Scott W.

    1992-09-01

    The design of a top-cover system is a very important aspect of the closure of sanitary landfills. Soil material properties, sequencing, and vegetation are critical to top-cover design. To date, very few field investigations have been undertaken to determine the effectiveness of these designs. Results from a field investigation of top-covers proposed for an active landfill site in south Florida are reported here. Measurements were made of each component of the water balance equation: ? S = [ P + I] - [ ET + R + Q] where S, P, I, ET, R, and Q represent water storage, rainfall, irrigation, evapotranspiration, surface runoff, and deep seepage, respectively. Deep seepage, determined using soil water tensiometers, is the amount of water infiltrating the landfill top-cover and is therefore the upper limit of potential leachate generation. Results indicate that the locally available rock tailings (carbonate silt) is an effective topliner component of the top-cover system. The results of the field investigation also showed that the EPA water balance model used to estimate infiltration during landfill design was greater than the actual field measurements.

  5. CH4/CO2 ratios indicate highly efficient methane oxidation by a pumice landfill cover-soil.

    PubMed

    Pratt, Chris; Walcroft, Adrian S; Deslippe, Julie; Tate, Kevin R

    2013-02-01

    Landfills that generate too little biogas for economic energy recovery can potentially offset methane (CH(4)) emissions through biological oxidation by methanotrophic bacteria in cover soils. This study reports on the CH(4) oxidation efficiency of a 10-year old landfill cap comprising a volcanic pumice soil. Surface CH(4) and CO(2) fluxes were measured using field chambers during three sampling intervals over winter and summer. Methane fluxes were temporally and spatially variable (-0.36 to 3044 mgCH(4)m(-2)h(-1)); but were at least 15 times lower than typical literature CH(4) fluxes reported for older landfills in 45 of the 46 chambers tested. Exposure of soil from this landfill cover to variable CH(4) fluxes in laboratory microcosms revealed a very strong correlation between CH(4) oxidation efficiency and CH(4)/CO(2) ratios, confirming the utility of this relationship for approximating CH(4) oxidation efficiency. CH(4)/CO(2) ratios were applied to gas concentrations from the surface flux chambers and indicated a mean CH(4) oxidation efficiency of 72%. To examine CH(4) oxidation with soil depth, we collected 10 soil depth profiles at random locations across the landfill. Seven profiles exhibited CH(4) removal rates of 70-100% at depths <60 cm, supporting the high oxidation rates observed in the chambers. Based on a conservative 70% CH(4) oxidation efficiency occurring at the site, this cover soil is clearly offsetting far greater CH(4) quantities than the 10% default value currently adopted by the IPCC. PMID:23186636

  6. N2O emissions from municipal solid waste landfills with selected infertile cover soils and leachate subsurface irrigation.

    PubMed

    Zhang, Hou-Hu; He, Pin-Jing; Shao, Li-Ming

    2008-12-01

    This study presents the field investigations into the effects of cover soils and leachate subsurface irrigation on N2O emissions from municipal solid waste landfills. Landfill Site A and Site B, covered with carefully chosen infertile soils, were selected to monitor their diurnal and seasonal variations of N2O emissions. The annual average N2O flux was 469 +/- 796 microg N2O-N m(-2) h(-1) in Site B with leachate subsurface irrigation, three times that of Site A without leachate irrigation. When an additional soil containing lower contents of carbon and nitrogen was introduced to cover part of Site B, its N2O fluxes decreased by 1-2 orders of magnitude compared with the left area of Site B. This suggested that carefully selected cover soils could substantially reduce N2O emissions even under leachate subsurface irrigation. Statistical analysis proved that the availabilities of soil moisture and mineralized nitrogen were the key parameters controlling landfill N2O emissions. PMID:18524440

  7. Modeling the effects of vegetation on methane oxidation and emissions through soil landfill final covers across different climates.

    PubMed

    Abichou, Tarek; Kormi, Tarek; Yuan, Lei; Johnson, Terry; Francisco, Escobar

    2015-02-01

    Plant roots are reported to enhance the aeration of soil by creating secondary macropores which improve the diffusion of oxygen into soil as well as the supply of methane to bacteria. Therefore, methane oxidation can be improved considerably by the soil structuring processes of vegetation, along with the increase of organic biomass in the soil associated with plant roots. This study consisted of using a numerical model that combines flow of water and heat with gas transport and oxidation in soils, to simulate methane emission and oxidation through simulated vegetated and non-vegetated landfill covers under different climatic conditions. Different simulations were performed using different methane loading flux (5-200 g m(-2) d(-1)) as the bottom boundary. The lowest modeled surface emissions were always obtained with vegetated soil covers for all simulated climates. The largest differences in simulated surface emissions between the vegetated and non-vegetated scenarios occur during the growing season. Higher average yearly percent oxidation was obtained in simulations with vegetated soil covers as compared to non-vegetated scenario. The modeled effects of vegetation on methane surface emissions and percent oxidation were attributed to two separate mechanisms: (1) increase in methane oxidation associated with the change of the physical properties of the upper vegetative layer and (2) increase in organic matter associated with vegetated soil layers. Finally, correlations between percent oxidation and methane loading into simulated vegetated and non-vegetated covers were proposed to allow decision makers to compare vegetated versus non-vegetated soil landfill covers. These results were obtained using a modeling study with several simplifying assumptions that do not capture the complexities of vegetated soils under field conditions. PMID:25475118

  8. Long-term distribution, mobility and plant availability of compost-derived heavy metals in a landfill covering soil.

    PubMed

    Businelli, D; Massaccesi, L; Said-Pullicino, D; Gigliotti, G

    2009-02-01

    The application of municipal waste compost (MWC) and other organic materials may serve to enhance soil fertility of earthen materials and mine spoils used in land reclamation activities, particularly in the recovery of degraded areas left by exhausted quarries, mines and landfill sites among others. The long-term distribution, mobility and phytoavailability of heavy metals in such anthropogenic soils were studied by collecting soil samples at different depths over a 10 y chronosequence subsequent to amendment of the top layer of a landfill covering soil with a single dose of mechanically-separated MWC. Amendment resulted in a significant enhancement of the metal loadings in the amended topsoils particularly for Cu, Zn and Pb, which were also the predominant metals in the compost utilised. Although metals were predominantly retained in the compost amended soil horizon, with time their vertical distribution resulted in a moderate enrichment of the underlying mineral horizons, not directly influenced by compost amendment. This enrichment generally resulted from the leaching of soluble organo-metal complexes and subsequent adsorption to mineral horizons. However, in the course of the 10-y experimental period, metal concentrations in the underlying horizons generally returned to background concentrations suggesting a potential loss of metals from the soil system. Analysis of the tissues of plants growing spontaneously on the landfill site suggests that metal phytoavailability was limited and generally species-dependent. PMID:19028398

  9. Seasonal greenhouse gas emissions (methane, carbon dioxide, nitrous oxide) from engineered landfills: daily, intermediate, and final California cover soils.

    PubMed

    Bogner, Jean E; Spokas, Kurt A; Chanton, Jeffrey P

    2011-01-01

    Compared with natural ecosystems and managed agricultural systems, engineered landfills represent a highly managed soil system for which there has been no systematic quantification of emissions from coexisting daily, intermediate, and final cover materials. We quantified the seasonal variability of CH, CO, and NO emissions from fresh refuse (no cover) and daily, intermediate, and final cover materials at northern and southern California landfill sites with engineered gas extraction systems. Fresh refuse fluxes (g m d [ SD]) averaged CH 0.053 ( 0.03), CO 135 ( 117), and NO 0.063 ( 0.059). Average CH emissions across all cover types and wet/dry seasons ranged over more than four orders of magnitude (<0.01-100 g m d) with most cover types, including both final covers, averaging <0.1 g m d with 10 to 40% of surface areas characterized by negative fluxes (uptake of atmospheric CH). The northern California intermediate cover (50 cm) had the highest CH fluxes. For both the intermediate (50-100 cm) and final (>200 cm) cover materials, below which methanogenesis was well established, the variability in gaseous fluxes was attributable to cover thickness, texture, density, and seasonally variable soil moisture and temperature at suboptimal conditions for CH oxidation. Thin daily covers (30 cm local soil) and fresh refuse generally had the highest CO and NO fluxes, indicating rapid onset of aerobic and semi-aerobic processes in recently buried refuse, with rates similar to soil ecosystems and windrow composting of organic waste. This study has emphasized the need for more systematic field quantification of seasonal emissions from multiple types of engineered covers. PMID:21546687

  10. Estimation of mass transport parameters of gases for quantifying CH{sub 4} oxidation in landfill soil covers

    SciTech Connect

    Im, J.; Moon, S.; Nam, K.; Kim, Y.-J.; Kim, J.Y.

    2009-02-15

    Methane (CH{sub 4}), which is one of the most abundant anthropogenic greenhouse gases, is produced from landfills. CH{sub 4} is biologically oxidized to carbon dioxide, which has a lower global warming potential than methane, when it passes through a cover soil. In order to quantify the amount of CH{sub 4} oxidized in a landfill cover soil, a soil column test, a diffusion cell test, and a mathematical model analysis were carried out. In the column test, maximum oxidation rates of CH{sub 4} (V{sub max}) showed higher values in the upper part of the column than those in the lower part caused by the penetration of O{sub 2} from the top. The organic matter content in the upper area was also higher due to the active microbial growth. The dispersion analysis results for O{sub 2} and CH{sub 4} in the column are counter-intuitive. As the upward flow rate of the landfill gas increased, the dispersion coefficient of CH{sub 4} slightly increased, possibly due to the effect of mechanical dispersion. On the other hand, as the upward flow rate of the landfill gas increased, the dispersion coefficient of O{sub 2} decreased. It is possible that the diffusion of gases in porous media is influenced by the counter-directional flow rate. Further analysis of other gases in the column, N{sub 2} and CO{sub 2}, may be required to support this hypothesis, but in this paper we propose the possibility that the simulations using the diffusion coefficient of O{sub 2} under the natural condition may overestimate the penetration of O{sub 2} into the soil cover layer and consequently overestimate the oxidation of CH{sub 4}.

  11. LANDFILL CONTAINMENT AND COVER SYSTEMS

    EPA Science Inventory

    The U.S. Environmental Protection Agency through its research and field experiences has developed control strategies for hazardous and municipal solid waste landfills and surface impoundments. hese control strategies include liner and cover systems. he liner systems include doubl...

  12. Capacity for Methane Oxidation in Landfill Cover Soils Measured in Laboratory-Scale Soil Microcosms

    PubMed Central

    Kightley, D.; Nedwell, D. B.; Cooper, M.

    1995-01-01

    Laboratory-scale soil microcosms containing different soils were permeated with CH(inf4) for up to 6 months to investigate their capacity to develop a methanotrophic community. Methane emissions were monitored continuously until steady states were established. The porous, coarse sand soil developed the greatest methanotrophic capacity (10.4 mol of CH(inf4) (middot) m(sup-2) (middot) day(sup-1)), the greatest yet reported in the literature. Vertical profiles of O(inf2), CH(inf4), and methanotrophic potential in the soils were determined at steady state. Methane oxidation potentials were greatest where the vertical profiles of O(inf2) and CH(inf4) overlapped. A significant increase in the organic matter content of the soil, presumably derived from methanotroph biomass, occurred where CH(inf4) oxidation was greatest. Methane oxidation kinetics showed that a soil community with a low methanotrophic capacity (V(infmax) of 258 nmol (middot) g of soil(sup-1) (middot) h(sup-1)) but relatively high affinity (k(infapp) of 1.6 (mu)M) remained in N(inf2)-purged control microcosms, even after 6 months without CH(inf4). We attribute this to a facultative, possibly mixotrophic, methanotrophic microbial community. When purged with CH(inf4), a different methanotrophic community developed which had a lower affinity (k(infapp) of 31.7 (mu)M) for CH(inf4) but a greater capacity (V(infmax) of 998 nmol (middot) g of soil(sup-1) (middot) h(sup-1)) for CH(inf4) oxidation, reflecting the enrichment of an active high-capacity methanotrophic community. Compared with the unamended control soil, amendment of the coarse sand with sewage sludge enhanced CH(inf4) oxidation capacity by 26%; K(inf2)HPO(inf4) amendment had no significant effect, while amendment with NH(inf4)NO(inf3) reduced the CH(inf4) oxidation capacity by 64%. In vitro experiments suggested that NH(inf4)NO(inf3) additions (10 and 71 (mu)mol (middot) g of soil(sup-1)) inhibited CH(inf4) oxidation by a nonspecific ionic effect rather than by specific inhibition by NH(inf4)(sup+). PMID:16534930

  13. Construction Costs of Six Landfill Cover Designs

    SciTech Connect

    Dwyer, S.F.

    1998-12-23

    A large-scale field demonstration comparing and contrasting final landfill cover designs has been constructed and is currently being monitored. Four alternative cover designs and two conventional designs (a RCRA Subtitle `D' Soil Cover and a RCRA Subtitle `C' Compacted Clay Cover) were constructed side-by-side for direct comparison. The demonstration is intended to evaluate the various cover designs based on their respective water balance performance, ease and reliability of construction, and cost. This paper provides an overview of the construction costs of each cover design.

  14. Effects of dry bulk density and particle size fraction on gas transport parameters in variably saturated landfill cover soil.

    PubMed

    Wickramarachchi, Praneeth; Kawamoto, Ken; Hamamoto, Shoichiro; Nagamori, Masanao; Moldrup, Per; Komatsu, Toshiko

    2011-12-01

    Landfill sites are emerging in climate change scenarios as a significant source of greenhouse gases. The compacted final soil cover at landfill sites plays a vital role for the emission, fate and transport of landfill gases. This study investigated the effects of dry bulk density, ?(b), and particle size fraction on the main soil-gas transport parameters - soil-gas diffusivity (D(p)/D(o), ratio of gas diffusion coefficients in soil and free air) and air permeability (k(a)) - under variably-saturated moisture conditions. Soil samples were prepared by three different compaction methods (Standard and Modified Proctor compaction, and hand compaction) with resulting ?(b) values ranging from 1.40 to 2.10 g cm(-3). Results showed that D(p) and k(a) values for the '+gravel' fraction (<35 mm) became larger than for the '-gravel' fraction (<2mm) under variably-saturated conditions for a given soil-air content (?), likely due to enhanced gas diffusion and advection through less tortuous, large-pore networks. The effect of dry bulk density on D(p) and k(a) was most pronounced for the '+gravel' fraction. Normalized ratios were introduced for all soil-gas parameters: (i) for gas diffusivity D(p)/D(f), the ratio of measured D(p) to D(p) in total porosity (f), (ii) for air permeability k(a)/k(a)(,pF4.1), the ratio of measured k(a) to k(a) at 1235 kPa matric potential (=pF 4.1), and (iii) for soil-air content, the ratio of soil-air content (?) to total porosity (f) (air saturation). Based on the normalized parameters, predictive power-law models for D(p)(?/f) and k(a)(?/f) models were developed based on a single parameter (water blockage factor M for D(p) and P for k(a)). The water blockage factors, M and P, were found to be linearly correlated to ?(b) values, and the effects of dry bulk density on D(p) and k(a) for both '+gravel' and '-gravel' fractions were well accounted for by the new models. PMID:21813272

  15. Instrumentation for continuous monitoring of meteorological variables and soil gas pressure in landfill cover

    SciTech Connect

    Moore, C.; Vogt, M.; Bogner, J.

    1986-09-01

    To examine changes in soil gas pressure relative to changes in atmospheric pressure and other meteorological variables, weather station sensors and electronic pressure transducers were interfaced with an RCA COSMAC microcomputer. The microcomputer control permitted simultaneous acquisition of pressure and meteorological data on cassette tape. Because the RCA unit uses CMOS circuitry, it can be battery operated, and is therefore well suited for collecting data at remote locations on landfills. A tape I/O board, an A/D converter board and two custom boards were required additions to the basic CDP18S601 board for this application. Meteorological data, including wind speed, wind direction, air temperature, precipitation, and solar radiation, were monitored using a Climatronics EWS system. Barometric pressure and soil gas pressures on subsurface probes were monitored using electronic pressure transducers with a 10 to 20 psia range. Cassette tape output was dumped directly to WYLBUR files on the Argonne National Laboratory (ANL) IBM 3033 mainframe for subsequent data analysis.

  16. Field Water Balance of Landfill Final Covers

    SciTech Connect

    Albright, William H.; Benson, Craig H.; Gee, Glendon W.; Roesler, Arthur C.; Abichou, Tarek; Apiwantragoon, Preecha; Lyles, Bradley F.; Rock, S A.

    2004-11-15

    Landfill covers are critical to waste containment, yet field performance of specific cover designs has not been well documented and seldom been compared in side-by-side testing. A study was conducted to asses the ability of landfill final covers to control percolation into underlying waste. Conventional covers employing resistive barriers as well as alternative covers relying on water-storage principles were monitored in large (10 x 20), instrumented drainage lysimeters over a range of climates at field sites in the United States. Surface runoff was a small fraction of the water balance (0-10%, 4% on average) and was nearly insensitive to the cover slope, cover design, or climate. Lateral drainage from internal drainage layers was also a small fraction of the water balance (0-5%, 2.0% on average). Average percolation rates for the conventional covers with composite barriers (geomembrane over fine soil) typically were less than 12 mm/yr (1.4% of precipitation) at humid locations and 1.5 mm/yr (0.4% of precipitation) at arid, semiarid, and subhumid locations. Average percolation rates for conventional covers with soil barriers in humid climates were between 52 and 195 mm/yr (6-17% of precipitation), probably due to preferential flow through defects in the soil barriers. Average percolation rates for alternative covers ranged between 33 and 160 mm/yr (6 and 18% if precipitation) in humid climates and generally less than 2.2 mm/yr (0.4% of precipitation) in arid, semiarid, and subhumid climates. One half (five) of the alternative covers in arid, semiarid, and subhumid climates transmitted less than 0.1 mm of percolation, but two transmitted much more percolation (26.8 and 52 mm) than anticipated during design. The data collected support conclusions from other studies that detailed, site-specific design procedures are very important for successful performance of alternative landfill covers.

  17. Field-scale tracking of active methane-oxidizing communities in a landfill cover soil reveals spatial and seasonal variability.

    PubMed

    Henneberger, Ruth; Chiri, Eleonora; Bodelier, Paul E L; Frenzel, Peter; Lke, Claudia; Schroth, Martin H

    2015-05-01

    Aerobic methane-oxidizing bacteria (MOB) in soils mitigate methane (CH4 ) emissions. We assessed spatial and seasonal differences in active MOB communities in a landfill cover soil characterized by highly variable environmental conditions. Field-based measurements of CH4 oxidation activity and stable-isotope probing of polar lipid-derived fatty acids (PLFA-SIP) were complemented by microarray analysis of pmoA genes and transcripts, linking diversity and function at the field scale. In situ?CH4 oxidation rates varied between sites and were generally one order of magnitude lower in winter compared with summer. Results from PLFA-SIP and pmoA transcripts were largely congruent, revealing distinct spatial and seasonal clustering. Overall, active MOB communities were highly diverse. Type Ia MOB, specifically Methylomonas and Methylobacter, were key drivers for CH4 oxidation, particularly at a high-activity site. Type II MOB were mainly active at a site showing substantial fluctuations in CH4 loading and soil moisture content. Notably, Upland Soil Cluster-gamma-related pmoA transcripts were also detected, indicating concurrent oxidation of atmospheric CH4 . Spatial separation was less distinct in winter, with Methylobacter and uncultured MOB mediating CH4 oxidation. We propose that high diversity of active MOB communities in this soil is promoted by high variability in environmental conditions, facilitating substantial removal of CH4 generated in the waste body. PMID:25186436

  18. Effects of dry bulk density and particle size fraction on gas transport parameters in variably saturated landfill cover soil

    SciTech Connect

    Wickramarachchi, Praneeth; Kawamoto, Ken; Hamamoto, Shoichiro; Nagamori, Masanao; Moldrup, Per; Komatsu, Toshiko

    2011-12-15

    Highlights: > The effects of soil physical properties on gas transport parameters were investigated. > Higher values of D{sub p} and k{sub a} exhibited in the '+gravel' than the '-gravel' fraction at same soil-air content ({epsilon}). > Recent power law models for D{sub p} (WLR) and k{sub a} (RPL) were modified. > Model parameters were linearly related to easily measurable dry bulk density ({rho}{sub b}). - Abstract: Landfill sites are emerging in climate change scenarios as a significant source of greenhouse gases. The compacted final soil cover at landfill sites plays a vital role for the emission, fate and transport of landfill gases. This study investigated the effects of dry bulk density, {rho}{sub b}, and particle size fraction on the main soil-gas transport parameters - soil-gas diffusivity (D{sub p}/D{sub o}, ratio of gas diffusion coefficients in soil and free air) and air permeability (k{sub a}) - under variably-saturated moisture conditions. Soil samples were prepared by three different compaction methods (Standard and Modified Proctor compaction, and hand compaction) with resulting {rho}{sub b} values ranging from 1.40 to 2.10 g cm{sup -3}. Results showed that D{sub p} and k{sub a} values for the '+gravel' fraction (<35 mm) became larger than for the '-gravel' fraction (<2 mm) under variably-saturated conditions for a given soil-air content ({epsilon}), likely due to enhanced gas diffusion and advection through less tortuous, large-pore networks. The effect of dry bulk density on D{sub p} and k{sub a} was most pronounced for the '+gravel' fraction. Normalized ratios were introduced for all soil-gas parameters: (i) for gas diffusivity D{sub p}/D{sub f}, the ratio of measured D{sub p} to D{sub p} in total porosity (f), (ii) for air permeability k{sub a}/k{sub a,pF4.1}, the ratio of measured k{sub a} to k{sub a} at 1235 kPa matric potential (=pF 4.1), and (iii) for soil-air content, the ratio of soil-air content ({epsilon}) to total porosity (f) (air saturation). Based on the normalized parameters, predictive power-law models for D{sub p}({epsilon}/f) and k{sub a}({epsilon}/f) models were developed based on a single parameter (water blockage factor M for D{sub p} and P for k{sub a}). The water blockage factors, M and P, were found to be linearly correlated to {rho}{sub b} values, and the effects of dry bulk density on D{sub p} and k{sub a} for both '+gravel' and '-gravel' fractions were well accounted for by the new models.

  19. Gas movement through fractured landfill cover materials

    SciTech Connect

    Bogner, J.E.; Moore, C.A.

    1986-01-01

    Bidirectional gas movement through fractured landfill cover materials is being studied at the Mallard North Landfill in DuPage County, Illinois. Vertical pressure and concentration gradients were monitored during changing meteorological and soil moisture conditions. Nests of probes for direct observation of subsurface soil gas pressures were installed in the top of the refuse and at depths of 1.2 m and 0.6 m. Subsurface gas pressures, barometric pressure, wind speed, wind direction, solar radiation, air temperature, and precipitation were continuously monitored. A field gas chromatograph permitted frequent analysis of methane, carbon dioxide, nitrogen, and oxygen in soil gas samples from the various probes. Tensiometers provided information on soil moisture conditions. During dry weather, soil gas pressures at all depths equilibrated rapidly with barometric pressure and exhibited diurnal variations that were inversely proportional to diurnal temperature variations. When cover materials became saturated, changes in soil gas pressures sometimes lagged behind changes in atmospheric pressure by two to three hours. Soil gas concentrations generally exhibited relatively small short-term variations, but responded over the longer term to changing soil moisture conditions. Carbon-dioxide:methane ratios suggest that an important near-surface process is the activity of methane-oxidizing bacteria, which consume methane that might otherwise be available to a gas recovery system.

  20. Filth flies associated with municipal solid waste and impact of delay in cover soil application on adult filth fly emergence in a sanitary landfill in Pulau Pinang, Malaysia.

    PubMed

    Nurita, A T; Hassan, A Abu

    2013-06-01

    Two types of municipal solid waste (MSW), newly arrived and 2 weeks old, were sampled from a sanitary landfill in Pulau Pinang, Malaysia at a fortnightly interval and kept under field conditions for 2 weeks. A total of 480 kg of each type of MSW was sampled to study species composition and impact of delays in cover soil applications on filth fly emergence. Out of 960 kg of MSW sampled, 9.2 ± 0.5 flies emerged per kilogram. Weekly adult fly emergence rates of newly arrived and 2-week-old waste did not differ significantly and MSW remained suitable for fly breeding for up to 1 month. Eight species of flies emerged from the MSW: namely, Musca domestica, Musca sorbens, Synthesiomyia nudiseta, Hydrotaea chalcogaster, Chrysomya megacephala, Lucilia cuprina, Hemipyrellia ligurriens and Sarcophaga sp. Newly arrived waste was determined to be the main source for M. domestica, C. megacephala and L. cuprina in the landfill owing to significantly higher mean emergence compared with 2-week-old waste. Musca sorbens was found in newly arrived waste but not in 2-week-old waste, suggesting that the species was able to survive transportation to landfill but unable to survive landfill conditions. Hemipyrellia ligurriens, H. chalcogaster and S. nudiseta were not imported into the landfill with MSW and pre-existing flies in and around the landfill itself may be their source. The results show that landfills can be a major source of fly breeding if cover soil or temporary cover is not applied daily or on a regular schedule. PMID:23302698

  1. Seasonal greenhouse gas emissions (methane, carbon dioxide, nitrous oxide) from engineered landfills: Daily, intermediate, and final California cover soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We quantified the seasonal variability of CH4, CO2, and N2O emissions from fresh refuse and daily, intermediate, and final cover materials at two California landfills. Fresh refuse fluxes (g m-2 d-1) averaged CH4 0.053[+/-0.03], CO2 135[+/-117], and N2O 0.063[+/-0.059]. Average CH4 emissions across ...

  2. Field Water Balance of Landfill Final Covers

    EPA Science Inventory

    Landfill covers are critical to waste containment, yet field performance of specific cover designs has not been well documented and seldom been compared in side-by-side testing. A study was conducted to assess the ability of landfill final covers to control percolation into unde...

  3. The use of engineered lightweight fill for landfill cover remediation

    SciTech Connect

    Poe, D.E.; Gardner, R.B.; Xiaoyu Fu

    1995-12-31

    In 1991, SCS was retained to provide design and construction engineering services to retrofit a landfill gas migration control system and regrade/repair an existing low-permeability soil final cover system for a 10-acre closed landfill located in west-central Florida. The final cover system modifications consisted of regrading the top of the landfill to re-establish positive drainage across and off of the top of the landfill. While active, the landfill had received municipal solid waste (MSW), commercial solid waste, and various industrial wastes and sludges. The landfill was closed in the early 1980`s. At the time of filling, the subject landfill was operated as a trench fill. A series of 40-foot deep trenches were excavated across the fill area, and the MSW was placed and compacted into the trenches. The soil excavated during construction of the trenches was used to construct berms along the sides of the individual trenches. No constructed bottom liner or leachate collection system was incorporated into the design. This report presents the results of a conceptual evaluation of utilizing expanded polystyrene blocks or Geofoam, as the lightweight fill component for an alternative cover remediation.

  4. The estimation of methane emissions from landfills with different cover systems

    NASA Astrophysics Data System (ADS)

    Park, S.; Lee, K.; Sung, K.

    2006-12-01

    Methane is a very potent greenhouse gas, second only to CO2 as an anthropogenic contributor to global warming. Landfills are important anthropogenic source in the CH4 emissions. Microbially mediated CH4 oxidation in landfills with conventional soil covers can serve as an efficient biological sink. Methane from modern sanitary landfills equipped with composite covers and gas collection system is vented directly to the atmosphere, except for some of the largest landfills at which it is collected and burned. However, previous laboratory research has shown that biofilters have the potential to reduce CH4 emissions from landfills with modern composite covers. In this study a CH4 emission model was developed. The model used the calculated CH4 oxidation rates to estimate CH4 emissions from landfills constructed with conventional soil covers, modern composite covers, and modern composite covers plus biofilters. According to the CH4 emission rates predicted by CH4 emission model, it was estimated that 90% of the generated CH4 was emitted to the atmosphere for landfills with modern composite cover. For landfills with modern composite cover plus biofilters, an average of only 9% of the generated CH4 was estimated to be emitted. For landfills with conventional covers, an average of 83% of the generated CH4 was estimated to be emitted. By comparing the CH4 emission rates from three different landfill types, the use of a properly managed biofilter should be an effective technique to reduce CH4 emissions from landfills.

  5. Modeling of H2S migration through landfill cover materials.

    PubMed

    Xu, Qiyong; Powell, Jon; Jain, Pradeep; Townsend, Timothy

    2014-01-15

    The emission of H2S from landfills in the United States is an emergent problem because measured concentrations within the waste mass and in ambient air have been observed at potentially unsafe levels for on-site workers and at levels that can cause a nuisance and potentially deleterious health impacts to surrounding communities. Though recent research has provided data on H2S concentrations that may be observed at landfills, facility operators and landfill engineers have limited predictive tools to anticipate and plan for potentially harmful H2S emissions. A one-dimensional gas migration model was developed to assist engineers and practitioners better evaluate and predict potential emission levels of H2S based on four factors: concentration of H2S below the landfill surface (C0), advection velocity (v), H2S effective diffusion coefficient (D), and H2S adsorption coefficient of landfill cover soil (?). Model simulations indicated that H2S migration into the atmosphere can be mitigated by reducing H2S diffusion and advection or using alternative cover soils with a high H2S adsorption coefficient. Laboratory column experiments were conducted to investigate the effects of the four parameters on H2S migration in cover soils and to calculate the adsorption coefficient of different cover materials. The model was validated by comparing results with laboratory column experiments. Based on the results, the laboratory column provides an effective way to estimate the H2S adsorption coefficient, which can then be incorporated into the developed model to predict the depth of cover soil required to reduce emitted H2S concentrations below a desired level. PMID:24316799

  6. GEOSYNTHETIC CLAY LINERS (GCLS) IN LANDFILL COVERS

    EPA Science Inventory

    Low permeability, compacted clay linters are commonly required as a barrier to water infiltration in landfill covers. elatively new material, known as geosynthetic clay liner (GCL), has been proposed as an alternative to a compacted clay liner. CL has the practical advantages of ...

  7. Biotic landfill cover treatments for mitigating methane emissions.

    PubMed

    Hilgeri, Helene; Humer, Marion

    2003-05-01

    Landfill methane (CH4) emissions have been cited as one of the anthropogenic gas releases that can and should be controlled to reduce global climate change. This article reviews recent research that identifies ways to enhance microbial consumption of the gas in the aerobic portion of a landfill cover. Use of these methods can augment CH4 emission reductions achieved by gas collection or provide a sole means to consume CH4 at small landfills that do not have active gas collection systems. Field studies indicate that high levels of CH4 removal can be achieved by optimizing natural soil microbial processes. Further, during biotic conversion, not all of the CH4 carbon is converted to carbon dioxide (CO2) gas and released to the atmosphere; some of it will be sequestered in microbial biomass. Because biotic covers can employ residuals from other municipal processes, financial benefits can also accrue from avoided costs for residuals disposal. PMID:12733810

  8. Report: landfill alternative daily cover: conserving air space and reducing landfill operating cost.

    PubMed

    Haughey, R D

    2001-02-01

    Title 40, Part 258 of the Code of Federal Regulations, Solid Waste Disposal Facility Criteria, commonly referred to as Subtitle D, became effective on October 9, 1993. It establishes minimum criteria for solid waste disposal facility siting, design, operations, groundwater monitoring and corrective action, and closure and postclosure maintenance, while providing EPA-approved state solid waste regulatory programs flexibility in implementing the criteria. Section 258.21(a) [40 CFR 258.21(a)] requires owners or operators of municipal solid waste landfill (MSWLF) units to cover disposed solid waste with 30cm of earthen material at the end of the operating day, or at more frequent intervals, if necessary, to control disease vectors, fires, odours, blowing litter, and scavenging. This requirement is consistent with already existing solid waste facility regulations in many states. For many MSWLFs, applying daily cover requires the importation of soil which increases landfill operating costs. Daily cover also uses valuable landfill air space, reducing potential operating revenue and the landfill's operating life. 40 CFR 258.21 (b) allows the director of an approved state to approve alternative materials of an alternative thickness if the owner or operator demonstrates that the alternative material and thickness will control disease vectors, fires, odours, blowing litter, and scavenging without presenting a threat to human health and the environment. Many different types of alternative daily cover (ADC) are currently being used, including geosynthetic tarps, foams, garden waste, and auto shredder fluff. These materials use less air space than soil and can reduce operating costs. This paper discusses the variety of ADCs currently being used around the country and their applicability to different climates and operating conditions, highlighting the more unusual types of ADC, the types of demonstrations necessary to obtain approval of ADC, and the impact on landfill air space and operating costs of ADC use. PMID:11525478

  9. METHANE PHYTOREMEDIATION BY VEGETATIVE LANDFILL COVER SYSTEMS

    EPA Science Inventory

    Landfill gas, consisting of methane and other gases, is produced from organic compounds degrading in landfills, contributes to global climate change, is toxic to various types of vegetation, and may pose a combustion hazard at higher concentrations. New landfills are required to ...

  10. Fly ash in landfill top covers - a review.

    PubMed

    Brnnvall, E; Kumpiene, J

    2016-01-01

    Increase of energy recovery from municipal solid waste by incineration results in the increased amounts of incineration residues, such as fly ash, that have to be taken care of. Material properties should define whether fly ash is a waste or a viable resource to be used for various applications. Here, two areas of potential fly ash application are reviewed: the use of fly ash in a landfill top cover either as a liner material or as a soil amendment in vegetation layer. Fly ashes from incineration of three types of fuel are considered: refuse derived fuel (RDF), municipal solid waste incineration (MSWI) and biofuel. Based on the observations, RDF and MSWI fly ash is considered as suitable materials to be used in a landfill top cover liner. Whereas MSWI and biofuel fly ashes based on element availability for plant studies, could be considered suitable for the vegetation layer of the top cover. Responsible application of MSWI ashes is, however, warranted in order to avoid element accumulation in soil and elevation of background values over time. PMID:26701627

  11. SETTLEMENT AND COVER SUBSIDENCE OF HAZARDOUS WASTE LANDFILLS

    EPA Science Inventory

    Numerical models using equations for linearly elastic deformation were developed to predict the maximum expected amount of settlement and cover subsidence and potential cracking of the cover by differential settlement in uniformly, horizontally layered hazardous waste landfills. ...

  12. On the performance of capillary barriers as landfill cover

    NASA Astrophysics Data System (ADS)

    Kmpf, M.; Montenegro, H.

    Landfills and waste heaps require an engineered surface cover upon closure. The capping system can vary from a simple soil cover to multiple layers of earth and geosynthetic materials. Conventional design features a compacted soil layer, which suffers from drying out and cracking, as well as root and animal intrusion. Capillary barriers consisting of inclined fine-over-coarse soil layers are investigated as an alternative cover system. Under unsaturated conditions, the textural contrast delays vertical drainage by capillary forces. The moisture that builds up above the contact will flow downdip along the interface of the layers. Theoretical studies of capillary barriers have identified the hydraulic properties of the layers, the inclination angle, the length of the field and the infiltration rate as the fundamental characteristics of the system. However, it is unclear how these findings can lead to design criteria for capillary barriers. To assess the uncertainty involved in such approaches, experiments have been carried out in a 8 m long flume and on large scale test sites (40 m x 15 m). In addition, the ability of a numerical model to represent the relevant flow processes in capillary barriers has been examined.

  13. Field measurements of frost penetration into a landfill cover that uses a paper sludge barrier

    SciTech Connect

    Moo-Young, H.K.; LaPlante, C.; Zimmie, T.F.; Quiroz, J.

    1999-07-01

    Frost penetration is a major environmental concern in landfill design. Freezing and thawing cycles may deteriorate the permeability of the liner or cap. In this study, the depth of frost penetration into a landfill cover that uses paper sludge as the impermeable barrier (the Hubbardston landfill in Massachusetts) was measured using a frost measurement system. A thermistor probe measured the temperature at various depths. Although temperature measurements are important, soil resistivity measurements are required to accurately predict the freezing level, since soil resistivity increases greatly upon freezing. A conductivity probe measured the half-bridge voltage between conductivity rings and a ground rod. Data were collected in data loggers. The data collected from 1992--1996 showed that the frost level did not penetrate the paper sludge capping layer. Heavy snow cover throughout the winters decreased the depth of frost penetration by insulating the landfill. The high water content in the sludge also contributed to the lack of freezing.

  14. Measurement of microbial biomass and activity in landfill soils.

    SciTech Connect

    Bogner, J. E.; Miller, R. M.; Spokas, K.; Environmental Research

    1995-01-01

    Two complementary techniques, which have been widely used to provide a general measure of microbial biomass or microbial activity in natural soils, were evaluated for their applicability to soils from the Mallard North and Mallard Lake Landfills, DuPage County, Illinois, U.S.A. Included were: (1) a potassium sulphate extraction technique with quantification of organic carbon for measurement of microbial biomass; and (2) an arginine ammonification technique for microbial activity. Four profiles consisting of replaced soils were sampled for this study; units included topsoil (mixed mollisol A and B horizons), compacted clay cover (local calcareous Wisconsinan age glacial till), and mixed soil/refuse samples. Internally consistent results across the four profiles and good correlations with other independent indicators of microbial activity (moisture, organic matter content, nitrogen, and phosphorus) suggest that, even though these techniques were developed mainly for natural mineral soils, they are also applicable to disturbed landfill soils.

  15. Landfill cover performance monitoring using time domain reflectometry

    SciTech Connect

    Neher, E.R.; Cotten, G.B.; McElroy, D.

    1998-03-01

    Time domain reflectometry (TDR) systems were installed to monitor soil moisture in two newly constructed landfill covers at the Idaho National Engineering and Environmental Laboratory. Each TDR system includes four vertical arrays with each array consisting of four TDR probes located at depths of 15, 30, 45, and 60 cm. The deepest probes at 60 cm were installed beneath a compacted soil layer to analyze infiltration through the compacted layer. Based on the TDR data, infiltration through the two covers between March and October, 1997 ranged from less than measurable to 1.5 cm. However, due to a prohibition on penetrating the buried waste and resulting limits on probe placement depths, deeper percolation was not evaluated. Some of the advantages found in the application of TDR for infiltration monitoring at this site are the relative low cost and rugged nature of the equipment. Also, of particular importance, the ability to collect frequent moisture measurements allows the capture and evaluation of soil moisture changes resulting from episodic precipitation events. Disadvantages include the inability to install the probes into the waste, difficulties in interpretation of infiltration during freeze/thaw periods, and some excessive noise in the data.

  16. Hydrologic studies of multilayered landfill covers for closure of waste landfills at Los Alamos, New Mexico

    SciTech Connect

    Nyhan, J.W.; Langhorst, G.J.; Martin, C.E.; Martinez, J.L.; Schofield, T.G.

    1993-06-01

    The Los Alamos National Laboratory examined water balance relationships for four different landfill cover designs containing engineered barriers. These field experiments were performed at Los Alamos, New Mexico, USA, in 1.0- by 10.0-m plots with downhill slopes of 5, 10, 15 and 25%. Field measurements of seepage, precipitation, interflow, runoff, and soil water content were collected in each of the 16 plots representing four slopes each with four cover designs: Conventional, EPA, Loam Capillary Barrier and Clay Loam Capillary Barrier. A seepage collection system was installed beneath each cover design to evaluate the influence of slope length on seepage using a series of four metal pans filled with medium gravel that were placed end-to-end in the bottom of each field plot. An automated waterflow datalogging system was used to collect hourly seepage, interflow and runoff data and consisted of 100 100-liter tanks, each of which was equipped with an ultrasonic liquid-level sensor and a motor-operated ball valve used to drain the tank. Soil water content was routinely monitored every six hours at each of 212 locations throughout the 16 plots with time domain reflectrometry (TDR) techniques using an automated and multiplexed measurement system.

  17. In situ performance assessment of different final cover systems of municipal solid waste (MSW) landfill (France)

    SciTech Connect

    Poignard, S.; Didier, G.; Guerbois, M.

    1999-07-01

    Different configurations of cover systems (clay and a geosynthetic clay layer), are tested in order to evaluate their performances, and they are compared on an experimental Municipal Solid Waste Landfill in France. Results are given about the influence of a drainage layer under the top soil, the slope, and the material.

  18. Field Performance Of Three Compacted Clay Landfill Covers

    EPA Science Inventory

    A study was conducted at sites in subtropical Georgia, seasonal and humid Iowa, and arid southeastern California to evaluate the field hydrology of compacted clay covers for final closure of landfills. Water balance of the covers was monitored with large (10 by 20 m ), instrumen...

  19. Analysis of Vegetative on Six Different Landfill Cover Profiles in an Arid Environment.

    SciTech Connect

    Dwyer, Stephen F.; McClellan, Yvonne; Reavis, Bruce A.; Dwyer, Brian P.; Newman, Gretchen; Wolters, Gale

    2005-05-01

    A large-scale field demonstration comparing final landfill cover designs was constructed and monitored at Sandia National Laboratories in Albuquerque, New Mexico. Two conventional designs (a RCRA Subtitle 'D' Soil Cover and a RCRA Subtitle 'C' Compacted Clay Cover) were constructed side-by-side with four alternative cover test plots designed for arid environments. The demonstration was intended to evaluate the various cover designs based on their respective water balance performance, ease and reliability of construction, and cost. A portion of this project involves the characterization of vegetation establishment and growth on the landfill covers. The various prototype landfill covers were expected to have varying flux rates (Dwyer et al 2000). The landfill covers were further expected to influence vegetation establishment and growth, which may impact site erosion potential and long-term site integrity. Objectives of this phase were to quantify the types of plants occupying each site, the percentage of ground covered by these plants, the density (number of plants per unit area) of plants, and the plant biomass production. The results of this vegetation analysis are presented in this report.3 DRAFT07/06/14AcknowledgementsWe would like to thank all technical and support staff from Sandia and the USDA Forest Service's Rocky Mountain Station not included in the authors' list of this document for their valuable contributions to this research. We would also like to acknowledge the Department of Energy's Subsurface Contaminants Focus Area for funding this work.4

  20. Soil gas investigations at the Sanitary Landfill

    SciTech Connect

    Wyatt, D.E.; Pirkle, R.J.; Masdea, D.J.

    1992-07-01

    A soil gas survey was performed at the 740-G Sanitary Landfill of Savannah River Plant during December, 1990. The survey monitored the presence and distribution of the C{sub 1}C{sub 4} hydrocarbons; the C{sub 5}-C{sub 10} normal paraffins; the aromatic hydrocarbons, BTXE; selected chlorinated hydrocarbons; and mercury. Significant levels of several of these contaminants were found associated with the burial site. In the northern area of the Landfill, methane concentrations ranged up to 63% of the soil gas and were consistently high on the western side of the access road. To the east of the access road in the northern and southern area high concentrations of methane were encountered but were not consistently high. Methane, the species found in highest concentration in the landfill, was generated in the landfill as the result of biological oxidation of cellulose and other organics to carbon dioxide followed by reduction of the carbon dioxide to methane. Distributions of other species are the result of burials in the landfill of solvents or other materials.

  1. Soil gas investigations at the Sanitary Landfill

    SciTech Connect

    Wyatt, D.E.; Pirkle, R.J.; Masdea, D.J.

    1992-07-01

    A soil gas survey was performed at the 740-G Sanitary Landfill of Savannah River Plant during December, 1990. The survey monitored the presence and distribution of the C[sub 1]C[sub 4] hydrocarbons; the C[sub 5]-C[sub 10] normal paraffins; the aromatic hydrocarbons, BTXE; selected chlorinated hydrocarbons; and mercury. Significant levels of several of these contaminants were found associated with the burial site. In the northern area of the Landfill, methane concentrations ranged up to 63% of the soil gas and were consistently high on the western side of the access road. To the east of the access road in the northern and southern area high concentrations of methane were encountered but were not consistently high. Methane, the species found in highest concentration in the landfill, was generated in the landfill as the result of biological oxidation of cellulose and other organics to carbon dioxide followed by reduction of the carbon dioxide to methane. Distributions of other species are the result of burials in the landfill of solvents or other materials.

  2. Potential application of biocover soils to landfills for mitigating toluene emission.

    PubMed

    Su, Yao; Pei, Junshen; Tian, Baohu; Fan, Fengxi; Tang, Mengling; Li, Wei; He, Ruo

    2015-12-15

    Biocover soils have been demonstrated to be a good alternative cover material to mitigate CH4 emission from landfills. To evaluate the potential of biocover soil in mitigating emissions of non-methane volatile organic compounds (NMVOCs) from landfills, simulated cover soil columns with the influx of toluene (chosen as typical of NMVOCs) concentrations of 102-1336mgm(-3) in the presence or absence of the major landfill gas components (i.e., CH4 and CO2) were conducted in this study. In the two experimental materials (waste biocover soils (WBS) and landfill cover soils (LCS)), higher toluene reduction was observed in WBS with respect to LCS. After the introduction of landfill gas, an increase of microbial diversity and relative abundance of toluene-degrading bacteria and methanotrophs occurred in WBS. To illustrate the role of toluene-degrading activity in mitigating toluene emissions through landfill covers, an analytical model was developed by incorporating the steady-state vapor transport with the first-order kinetics of aerobic biodegradation limited by O2 availability. This study demonstrated that biocover soils have great potential in applying to landfills for mitigating toluene emission to the atmosphere. PMID:26073517

  3. Large-Scale Field Study of Landfill Covers at Sandia National Laboratories

    SciTech Connect

    Dwyer, S.F.

    1998-09-01

    A large-scale field demonstration comparing final landfill cover designs has been constructed and is currently being monitored at Sandia National Laboratories in Albuquerque, New Mexico. Two conventional designs (a RCRA Subtitle `D' Soil Cover and a RCRA Subtitle `C' Compacted Clay Cover) were constructed side-by-side with four alternative cover test plots designed for dry environments. The demonstration is intended to evaluate the various cover designs based on their respective water balance performance, ease and reliability of construction, and cost. This paper presents an overview of the ongoing demonstration.

  4. Infiltration control landfill cover demonstration at Marine Corps Base, Hawaii. Final report, November 1995--March 1998

    SciTech Connect

    Karr, L.; Harre, B.; Hakonson, T.E.

    1999-06-01

    To demonstrate the effectiveness of alternative landfill caps, the Naval Facilities Engineering Service Center (NFESC) teamed with the Los Alamos National Laboratory and Colorado State University to investigate the performance of a variety of vegetative caps. Demonstration caps were installed at Marine Corps Base Hawaii (MCBH) Kaneohe Bay in 1994. The study used an innovative but simple concept to manipulate the fate of rain water falling on waste sites with moderate to high precipitation. The infiltration of water through the cap, or cover, was controlled by combining the powerful forces of evapotranspiration (ET) with engineered structures that limited infiltration of precipitation into the soil. This approach relied on diverting a sufficient amount of precipitation to control runoff so that any water that infiltrated into the soil was easily removed by ET. The study demonstrated two infiltration control (IC) designs, one involving a 20% enhancement of runoff and the other a 40% enhancement, with a conventional ET soil cover design to serve as a control (i.e., basis of comparison). This report summarizes all the data collected during the MCBH landfill cover demonstration project between 11/1995--3/1998. Water balance data from the study were also compared against corresponding data for a Resource Conservation and Recovery Act (RCRA) clay cap obtained from the EPA Hydrologic Evaluation of Landfill Performance (HELP), version 3.0b, water balance model. The results, based upon 28 months of field monitoring data, support the concept of using runoff enhancement to manage percolation of water through a landfill.

  5. Impact of different plants on the gas profile of a landfill cover

    SciTech Connect

    Reichenauer, Thomas G.; Watzinger, Andrea; Riesing, Johann; Gerzabek, Martin H.

    2011-05-15

    Research highlights: > Plants influence gas profile and methane oxidation in landfill covers. > Plants regulate water content and increase the availability of oxygen for methane oxidation. > Plant species with deep roots like alfalfa showed more stimulation of methane oxidation than plants with shallow root systems like grasses. - Abstract: Methane is an important greenhouse gas emitted from landfill sites and old waste dumps. Biological methane oxidation in landfill covers can help to reduce methane emissions. To determine the influence of different plant covers on this oxidation in a compost layer, we conducted a lysimeter study. We compared the effect of four different plant covers (grass, alfalfa + grass, miscanthus and black poplar) and of bare soil on the concentration of methane, carbon dioxide and oxygen in lysimeters filled with compost. Plants were essential for a sustainable reduction in methane concentrations, whereas in bare soil, methane oxidation declined already after 6 weeks. Enhanced microbial activity - expected in lysimeters with plants that were exposed to landfill gas - was supported by the increased temperature of the gas in the substrate and the higher methane oxidation potential. At the end of the first experimental year and from mid-April of the second experimental year, the methane concentration was most strongly reduced in the lysimeters containing alfalfa + grass, followed by poplar, miscanthus and grass. The observed differences probably reflect the different root morphology of the investigated plants, which influences oxygen transport to deeper compost layers and regulates the water content.

  6. DESIGN AND CONSTRUCTION OF COVERS FOR SOLID WASTE LANDFILLS

    EPA Science Inventory

    The report provides guidelines in selection, design, and construction of cover for management of municipal, industrial, and hazardous solid wastes (with the exception of radioactive waste). Natural soils as cover are the principal subject; however, synthetic membranes, chemicals,...

  7. LANDFILL LEACHATE CLOGGING OF GEOTEXTILE (AND SOIL) FILTERS

    EPA Science Inventory

    The primary leachate collection system of most solid waste landfills contains a filter layer which has historically been a granular soil. ecently, however, various types of geotextile filters have been used to replace the natural soil filters. roject using six different landfill ...

  8. EVALUATION OF HYDROLOGIC MODELS IN THE DESIGN OF STABLE LANDFILL COVERS

    EPA Science Inventory

    The study evaluates the utility of two hydrologic models in designing stable landfill cover systems. The models evaluated were HELP (Hydrologic Evaluation of Landfill Performance) and CREAMS (Chemicals, Runoff, and Erosion from Agricultural Management Systems). Studies of paramet...

  9. Optimization of diagnostic microarray for application in analysing landfill methanotroph communities under different plant covers.

    PubMed

    Stralis-Pavese, Nancy; Sessitsch, Angela; Weilharter, Alexandra; Reichenauer, Thomas; Riesing, Johann; Csontos, Jzsef; Murrell, J Colin; Bodrossy, Levente

    2004-04-01

    Landfill sites are responsible for 6-12% of global methane emission. Methanotrophs play a very important role in decreasing landfill site methane emissions. We investigated the methane oxidation capacity and methanotroph diversity in lysimeters simulating landfill sites with different plant vegetations. Methane oxidation rates were 35 g methane m-2 day-1 or higher for planted lysimeters and 18 g methane m-2 day-1 or less for bare soil controls. Best methane oxidation, as displayed by gas depth profiles, was found under a vegetation of grass and alfalfa. Methanotroph communities were analysed at high throughput and resolution using a microbial diagnostic microarray targeting the particulate methane monooxygenase (pmoA) gene of methanotrophs and functionally related bacteria. Members of the genera Methylocystis and Methylocaldum were found to be the dominant members in landfill site simulating lysimeters. Soil bacterial communities in biogas free control lysimeters, which were less abundant in methanotrophs, were dominated by Methylocaldum. Type Ia methanotrophs were found only in the top layers of bare soil lysimeters with relatively high oxygen and low methane concentrations. A competetive advantage of type II methanotrophs over type Ia methanotrophs was indicated under all plant covers investigated. Analysis of average and individual results from parallel samples was used to identify general trends and variations in methanotroph community structures in relation to depth, methane supply and plant cover. The applicability of the technology for the detection of environmental perturbations was proven by an erroneous result, where an unexpected community composition detected with the microarray indicated a potential gas leakage in the lysimeter being investigated. PMID:15008813

  10. Soil contaminations in landfill: a case study of the landfill in Czech Republic

    NASA Astrophysics Data System (ADS)

    Adamcová, D.; Vaverková, M. D.; Bartoň, S.; Havlíček, Z.; Břoušková, E.

    2015-10-01

    Phytotoxicity test was determined to assess ecotoxicity of landfill soil. Sinapis alba L. was used as heavy metals bioindicator. Soil samples 1-8, which were taken from the landfill body, edge of the landfill body and its vicinity meet the limits for heavy metals Co, Cd, Pb, and Zn specified in the applicable legislation. Hg and Mn threshold values are not established in legislation, but values have been determined for the needs of the landfill operator. For heavy metals Cr, Cu, and Ni sample 2 exceeded the threshold values, which attained the highest values of all the samples tested for Cr, Cu and Ni. For Cr and Ni the values were several times higher than values of the other samples. The second highest values for Cr, Cu, and Ni showed sample 6 and 7. Both samples exceeded the set limits. An increase in plant biomass was observed in plants growing on plates with soil samples, but no changes in appearance, slow growth or necrotic lesions appeared. Ecotoxicity tests show that tested soils (concentration of 50 %) collected from the landfill body, edge of the landfill body and its vicinity reach high percentage values of germination capacity of seeds of Sinapis alba L. (101-137 %). At a concentration of 25 %, tested soil samples exhibit lower values of germination capacity; in particular samples 3 to 8, yet the seed germination capacity in all 8 samples of tested soils range between 86 and 137 %.

  11. Soil contamination in landfills: a case study of a landfill in Czech Republic

    NASA Astrophysics Data System (ADS)

    Adamcová, D.; Vaverková, M. D.; Bartoň, S.; Havlíček, Z.; Břoušková, E.

    2016-02-01

    A phytotoxicity test was determined to assess ecotoxicity of landfill soil. Sinapis alba L. was used as a bioindicator of heavy metals. Soil samples 1-8, which were taken from the landfill body, edge of the landfill body, and its vicinity meet the limits for heavy metals Co, Cd, Pb, and Zn specified in the applicable legislation. Hg and Mn threshold values are not established in legislation, but values have been determined for the needs of the landfill operator. For heavy metals Cr, Cu, and Ni sample 2 exceeded the threshold values, which attained the highest values of all the samples tested for Cr, Cu, and Ni. For Cr and Ni the values were several times higher than values of the other samples. The second highest values for Cr, Cu, and Ni showed sample 6 and 7. Both samples exceeded the set limits. An increase in plant biomass was observed in plants growing on plates with soil samples, but no changes in appearance, slow growth, or necrotic lesions appeared. Ecotoxicity tests show that tested soils (concentration of 50 %) collected from the landfill body, edge of the landfill body, and its vicinity reach high percentage values of germination capacity of seeds of Sinapis alba L. (101-137 %). At a concentration of 25 %, tested soil samples exhibit lower values of germination capacity - in particular samples 3 to 8 - yet the seed germination capacity in all eight samples of tested soils ranges between 86 and 137 %.

  12. Impact of using high-density polyethylene geomembrane layer as landfill intermediate cover on landfill gas extraction.

    PubMed

    Chen, Zezhi; Gong, Huijuan; Zhang, Mengqun; Wu, Weili; Liu, Yu; Feng, Jin

    2011-05-01

    Clay is widely used as a traditional cover material for landfills. As clay becomes increasingly costly and scarce, and it also reduces the storage capacity of landfills, alternative materials with low hydraulic conductivity are employed. In developing countries such as China, landfill gas (LFG) is usually extracted for utilization during filling stage, therefore, the intermediate covering system is an important part in a landfill. In this study, a field test of LFG extraction was implemented under the condition of using high-density polyethylene (HDPE) geomembrane layer as the only intermediate cover on the landfill. Results showed that after welding the HDPE geomembranes together to form a whole airtight layer upon a larger area of landfill, the gas flow in the general pipe increased 25% comparing with the design that the HDPE geomembranes were not welded together, which means that the gas extraction ability improved. However as the heat isolation capacity of the HDPE geomembrane layer is low, the gas generation ability of a shallow landfill is likely to be weakened in cold weather. Although using HDPE geomembrane layer as intermediate cover is acceptable in practice, the management and maintenance of it needs to be investigated in order to guarantee its effective operation for a long term. PMID:21232931

  13. Gas breakthrough and emission through unsaturated compacted clay in landfill final cover.

    PubMed

    Ng, C W W; Chen, Z K; Coo, J L; Chen, R; Zhou, C

    2015-10-01

    Determination of gas transport parameters in compacted clay plays a vital role for evaluating the effectiveness of soil barriers. The gas breakthrough pressure has been widely studied for saturated swelling clay buffer commonly used in high-level radioactive waste disposal facility where the generated gas pressure is very high (in the order of MPa). However, compacted clay in landfill cover is usually unsaturated and the generated landfill gas pressure is normally low (typically less than 10 kPa). Furthermore, effects of clay thickness and degree of saturation on gas breakthrough and emission rate in the context of unsaturated landfill cover has not been quantitatively investigated in previous studies. The feasibility of using unsaturated compacted clay as gas barrier in landfill covers is thus worthwhile to be explored over a wide range of landfill gas pressures under various degrees of saturation and clay thicknesses. In this study, to evaluate the effectiveness of unsaturated compacted clay to minimize gas emission, one-dimensional soil column tests were carried out on unsaturated compacted clay to determine gas breakthrough pressures at ultimate limit state (high pressure range) and gas emission rates at serviceability limit state (low pressure range). Various degrees of saturation and thicknesses of unsaturated clay sample were considered. Moreover, numerical simulations were carried out using a coupled gas-water flow finite element program (CODE-BRIGHT) to better understand the experimental results by extending the clay thickness and varying the degree of saturation to a broader range that is typical at different climate conditions. The results of experimental study and numerical simulation reveal that as the degree of saturation and thickness of clay increase, the gas breakthrough pressure increases but the gas emission rate decreases significantly. Under a gas pressure of 10 kPa (the upper bound limit of typical landfill gas pressure), a 0.6m or thicker compacted clay is able to prevent gas breakthrough at degree of saturation of 60% or above (in humid regions). Furthermore, to meet the limit of gas emission rate set by the Australian guideline, a 0.6m-thick clay layer may be sufficient even at low degree of saturation (i.e., 10% like in arid regions). PMID:26184895

  14. Effect of temperature and oxidation rate on carbon-isotope fractionation during methane oxidation by landfill cover materials.

    PubMed

    Chanton, Jeffrey P; Powelson, David K; Abichou, Tarek; Fields, Dana; Green, Roger

    2008-11-01

    The quantification of methane oxidation is one of the major uncertainties in estimating CH4 emissions from landfills. Stable isotope methods provide a useful field approach for the quantification of methane oxidation in landfill cover soils. The approach relies upon the difference between the isotopic composition of oxidized gas at the location of interest and anaerobic zone CH4 and knowledge of alpha(ox), a term that describes the isotopic fractionation of the methanotrophic bacteria in their discrimination against (13)CH4. Natural variability in alpha(0x) in different landfill soils and the effect of temperature and other environmental factors on this parameter are not well defined. Therefore, standard determinations of alpha(ox), batch incubations of landfill cover soils with CH4, were conducted to determine alpha(ox) under a variety of conditions. When these results were combined with those of previous landfill incubation studies, the average alpha(ox) at 25 degrees C was 1.022 +/- 0.0015. alpha(ox) decreased with increasing temperature (-0.00039 alpha(ox) degrees C(-1)) overthe temperature range of 3-35 degrees C. alpha(ox) was found to be higher when determined after CH4-free storage and declined following CH4 pretreatment. alpha(ox) declined nonlinearly with increasing methane oxidation rate, Vmax. PMID:19031866

  15. Suitability of Hydrologic Evaluation of Landfill Performance (HELP) model of the US Environmental Protection Agency for the simulation of the water balance of landfill cover systems

    NASA Astrophysics Data System (ADS)

    Berger, K.; Melchior, S.; Miehlich, G.

    1996-12-01

    Cover systems are widely used to safeguard landfills and contaminated sites. The evaluation of the water balance is crucial for the design of landfill covers. The Hydrologic Evaluation of Landfill Performance (HELP) model of the US Environmental Protection Agency was developed for this purpose. This paper discusses some limitations of version 2 of this model and some operational difficulties for the use of this model in Germany, which has been developed for the United States. The model results are tested against field data of the water balance, measured on test fields on the Georgswerder landfill in Hamburg. Theoretically, HELP considers gravitational forces as driving forces of water flow only. Therefore capillary barriers cannot be simulated. Furthermore, the formation of and the flow through macropores are not considered, a main critical process that the diminishes the effectiveness of compacted soil liners. In the output comparison, the matching of measured and simulated data is quite good for lateral drainage, but failed for surface runoff and liner leakage through compacted soil liners. A further validation study is planned for HELP version 3 using a broader range of test field data.

  16. Scaling methane oxidation: From laboratory incubation experiments to landfill cover field conditions

    SciTech Connect

    Abichou, Tarek; Mahieu, Koenraad; Chanton, Jeff; Romdhane, Mehrez; Mansouri, Imane

    2011-05-15

    Evaluating field-scale methane oxidation in landfill cover soils using numerical models is gaining interest in the solid waste industry as research has made it clear that methane oxidation in the field is a complex function of climatic conditions, soil type, cover design, and incoming flux of landfill gas from the waste mass. Numerical models can account for these parameters as they change with time and space under field conditions. In this study, we developed temperature, and water content correction factors for methane oxidation parameters. We also introduced a possible correction to account for the different soil structure under field conditions. These parameters were defined in laboratory incubation experiments performed on homogenized soil specimens and were used to predict the actual methane oxidation rates to be expected under field conditions. Water content and temperature corrections factors were obtained for the methane oxidation rate parameter to be used when modeling methane oxidation in the field. To predict in situ measured rates of methane with the model it was necessary to set the half saturation constant of methane and oxygen, K{sub m}, to 5%, approximately five times larger than laboratory measured values. We hypothesize that this discrepancy reflects differences in soil structure between homogenized soil conditions in the lab and actual aggregated soil structure in the field. When all of these correction factors were re-introduced into the oxidation module of our model, it was able to reproduce surface emissions (as measured by static flux chambers) and percent oxidation (as measured by stable isotope techniques) within the range measured in the field.

  17. Field Performance of Three Compacted Clay Landfill Covers

    SciTech Connect

    Albright, William H.; Benson, Craig H.; Gee, Glendon W.; Abichou, Tarek; Tyler, Scott W.; Rock, Steven

    2006-11-01

    A study was conducted at sites in subtropical Georgia, seasonal and humid Iowa, and arid southeastern California to evaluate the field hydrology of compacted clay covers for final closure of landfills.Water balance of the covers was monitored with large (10 by 20 m), instrumented drainage lysimeters for 2 to 4 yr. Initial drainage at the Iowa and California sites was ,32 mm yr21 (i.e., unit gradient flow for a hydraulic conductivity of 1027 cm s21, the regulatory standard for the clay barriers in this study); initial drainage rate at the Georgia site was about 80 mm yr21. The drainage rate at all sites increased by factors ranging from 100 to 750 during the monitoring periods and in each case the drainage rate exceeded 32 mm yr21 by the end of the monitoring period. The drainage rates developed a rapid response to precipitation events, suggesting that increases in drainage rate were the result of preferential flow. Although no direct observations of preferential flow paths were made, field measurements of water content and temperature at all three sites suggested that desiccation or freezethaw cycling probably resulted in formation of preferential flow paths through the barrier layers. Data from all three sites showed the effectiveness of all three covers as hydraulic barriers diminished during the 2 to 4 yr monitoring period, which was short compared with the required design life (often 30 yr) of most waste containment facilities.

  18. Monitoring of Gin Drinkers' Bay landfill, Hong Kong: II. Gas contents, soil properties, and vegetation performance on the side slope

    NASA Astrophysics Data System (ADS)

    Wong, M. H.; Yu, C. T.

    1989-11-01

    This second part of the study concerned the plant cover, gas contents, and soil properties of the side slope area of the landfill, which is not protected against gas infiltration. Five different sites on the slope and a control site outside the landfill were chosen, and pipes were installed in the region. Gas contents were tested, and plant cover recorded by quadrat analysis Over 20 species of grasses, herbs, and vines were present on the slope The relative adaptabilities of the species were ranked according to the abundance of the plants Plant cover was found to be negatively correlated with landfill gas contents. The landfill soil had elevated contents of nitrogen, organic carbon, and extractable metals Total nitrogen, ammonia nitrogen, and extractable lead were further identified to be negatively correlated while available phosphate was positively correlated with plant cover

  19. Accelerated carbonation of steel slags in a landfill cover construction

    SciTech Connect

    Diener, S.; Andreas, L.; Herrmann, I.; Ecke, H.; Lagerkvist, A.

    2010-01-15

    Steel slags from high-alloyed tool steel production were used in a full scale cover construction of a municipal solid waste (MSW) landfill. In order to study the long-term stability of the steel slags within the final cover, a laboratory experiment was performed. The effect on the ageing process, due to i.e. carbonation, exerted by five different factors resembling both the material characteristics and the environmental conditions is investigated. Leaching behaviour, acid neutralization capacity and mineralogy (evaluated by means of X-ray diffraction, XRD, and thermogravimetry/differential thermal analysis, TG/DTA) are tested after different periods of ageing under different conditions. Samples aged for 3 and 10 months were evaluated in this paper. Multivariate data analysis was used for data evaluation. The results indicate that among the investigated factors, ageing time and carbon dioxide content of the atmosphere were able to exert the most relevant effect. However, further investigations are required in order to clarify the role of the temperature.

  20. Design of top covers supporting aerobic in situ stabilization of old landfills - An experimental simulation in lysimeters

    SciTech Connect

    Hrad, Marlies; Huber-Humer, Marion; Wimmer, Bernhard; Reichenauer, Thomas G.

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer Tested engineered covers as surrogate to gas extraction during and after in situ aeration. Black-Right-Pointing-Pointer Examined how covers influence gas emissions, water balance and leachate generation. Black-Right-Pointing-Pointer Investigated effect of top covers on air-distribution in waste mass during aeration. Black-Right-Pointing-Pointer We suggest criteria and cover design to meet the demands during and after aeration. Black-Right-Pointing-Pointer Such cover systems may offer greenhouse gas emission reduction also after active aeration. - Abstract: Landfill aeration by means of low pressure air injection is a promising tool to reduce long term emissions from organic waste fractions through accelerated biological stabilization. Top covers that enhance methane oxidation could provide a simple and economic way to mitigate residual greenhouse gas emissions from in situ aerated landfills, and may replace off-gas extraction and treatment, particularly at smaller and older sites. In this respect the installation of a landfill cover system adjusted to the forced-aerated landfill body is of great significance. Investigations into large scale lysimeters (2 Multiplication-Sign 2 Multiplication-Sign 3 m) under field conditions have been carried out using different top covers including compost materials and natural soils as a surrogate to gas extraction during active low pressure aeration. In the present study, the emission behaviour as well as the water balance performance of the lysimeters has been investigated, both prior to and during the first months of in situ aeration. Results reveal that mature sewage sludge compost (SSC) placed in one lysimeter exhibits in principle optimal ambient conditions for methanotrophic bacteria to enhance methane oxidation. Under laboratory conditions the mature compost mitigated CH{sub 4} loadings up to 300 l CH{sub 4}/m{sup 2} d. In addition, the compost material provided high air permeability even at 100% water holding capacity (WHC). In contrast, the more cohesive, mineral soil cover was expected to cause a notably uniform distribution of the injected air within the waste layer. Laboratory results also revealed sufficient air permeability of the soil materials (TS-F and SS-Z) placed in lysimeter C. However, at higher compaction density SS-Z became impermeable at 100% WHC. Methane emissions from the reference lysimeter with the smaller substrate cover (12-52 g CH{sub 4}/m{sup 2} d) were significantly higher than fluxes from the other lysimeters (0-19 g CH{sub 4}/m{sup 2} d) during in situ aeration. Regarding water balance, lysimeters covered with compost and compost-sand mixture, showed the lowest leachate rate (18-26% of the precipitation) due to the high water holding capacity and more favourable plant growth conditions compared to the lysimeters with mineral, more cohesive, soil covers (27-45% of the precipitation). On the basis of these results, the authors suggest a layered top cover system using both compost material as well as mineral soil in order to support active low-pressure aeration. Conventional soil materials with lower permeability may be used on top of the landfill body for a more uniform aeration of the waste due to an increased resistance to vertical gas flow. A compost cover may be built on top of the soil cover underlain by a gas distribution layer to improve methane oxidation rates and minimise water infiltration. By planting vegetation with a high transpiration rate, the leachate amount emanating from the landfill could be further minimised. The suggested design may be particularly suitable in combination with intermittent in situ aeration, in the later stage of an aeration measure, or at very small sites and shallow deposits. The top cover system could further regulate water infiltration into the landfill and mitigate residual CH{sub 4} emissions, even beyond the time of active aeration.

  1. Reevaluating the role of soil layers in landfill construction

    SciTech Connect

    Roberts, M.; Larky, A.

    1996-05-01

    While most Subtitle D landfills are required to use a clay soil layer to protect the bottom liner or leachate collection system, many have begun experimenting- and succeeding-with use of ground tires, wood chips, sewage sludge, compost and other materials in place of the soil.

  2. Field Performance of A Compacted Clay Landfill Final cover At A Humid Site

    SciTech Connect

    Albright, William H.; Benson, Craig H.; Gee, Glendon W.; Abichou, Tarek; Mcdonald, Eric V.; Tyler, Scott W.; Rock, Steven

    2006-11-01

    A study was conducted in southern Georgia, USA to evaluate how the hydraulic properties of the compacted clay barrier layer in a landfill final cover changed over a 4-yr service life. The cover was part of a test section constructed in a large drainage lysimeter that allowed CE Database subject headings: landfill, hydrogeology, compacted soils, lysimeters, desiccation continuous monitoring of the water balance. Patterns in the drainage (i.e., flow from the bottom of the cover) record suggest that preferential flow paths developed in the clay barrier soon after construction, apparently in response to desiccation cracking. After four years, the clay barrier was excavated and examined for changes in soil structure and hydraulic conductivity. Tests were conducted in situ with a sealed double-ring infiltrometer and two-stage borehole permeameters and in the laboratory on hand-carved blocks taken during construction and after four years of service. The in situ and laboratory tests indicated that the hydraulic conductivity increased approximately three orders of magnitude (from ? 10-7 to ? 10-4 cm s-1) during the service life. A dye tracer test and soil structure analysis showed that extensive cracking and root development occurred throughout the entire depth of the barrier layer. Laboratory tests on undisturbed specimens of the clay barrier indicated that the hydraulic conductivity of damaged clay barriers can be under-estimated significantly if small specimens (e.g., tube samples) are used for hydraulic conductivity assessment. The findings also indicate that clay barriers must be protected from desiccation and root intrusion if they are expected to function as intended, even at sites in warm, humid locations.

  3. Observations on the methane oxidation capacity of landfill soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field data and two independent models indicate that landfill cover methane (CH4) oxidation should not be considered as a constant 10% or any other single value. Percent oxidation is a decreasing exponential function of the total methane flux rate into the cover and is also dependent on climate and c...

  4. Prediction of long-term erosion from landfill covers in the southwest

    SciTech Connect

    Anderson, C.E.; Stormont, J.C.

    1997-12-31

    Erosion is a primary stressor of landfill covers, especially for climates with high intensity storms and low native plant density. Rills and gullies formed by discrete events can damage barrier layers and induce failure. Geomorphologic, empirical and physical modeling procedures are available to provide estimates of surface erosion, but numerical modeling requires accurate representation of the severe rainfall events that generate erosion. The National Weather Service precipitation frequency data and estimates of 5, 10, 15, 30 and 60-minute intensity can be statistically combined in a numerical model to obtain long-term erosion estimates. Physically based numerical models using the KINEROS and AHYMO programs have been utilized to predict the erosion from a southwestern landfill or waste containment site with 0.03, 0.05 and 0.08 meter per meter surface slopes. Results of AHYMO modeling were within 15 percent of average annual values computed with the empirical Universal Soil Loss Equation. However, the estimation of rill and gully formation that primarily degrades cover systems requires quantifying single events. For Southwestern conditions, a single 10-year storm can produce erosion quantifies equal to three times the average annual erosion and a 100-year storm can produce five times the average annual erosion.

  5. Design of top covers supporting aerobic in situ stabilization of old landfills--an experimental simulation in lysimeters.

    PubMed

    Hrad, Marlies; Huber-Humer, Marion; Wimmer, Bernhard; Reichenauer, Thomas G

    2012-12-01

    Landfill aeration by means of low pressure air injection is a promising tool to reduce long term emissions from organic waste fractions through accelerated biological stabilization. Top covers that enhance methane oxidation could provide a simple and economic way to mitigate residual greenhouse gas emissions from in situ aerated landfills, and may replace off-gas extraction and treatment, particularly at smaller and older sites. In this respect the installation of a landfill cover system adjusted to the forced-aerated landfill body is of great significance. Investigations into large scale lysimeters (2 2 3m) under field conditions have been carried out using different top covers including compost materials and natural soils as a surrogate to gas extraction during active low pressure aeration. In the present study, the emission behaviour as well as the water balance performance of the lysimeters has been investigated, both prior to and during the first months of in situ aeration. Results reveal that mature sewage sludge compost (SSC) placed in one lysimeter exhibits in principle optimal ambient conditions for methanotrophic bacteria to enhance methane oxidation. Under laboratory conditions the mature compost mitigated CH(4) loadings up to 300 lCH(4)/m(2)d. In addition, the compost material provided high air permeability even at 100% water holding capacity (WHC). In contrast, the more cohesive, mineral soil cover was expected to cause a notably uniform distribution of the injected air within the waste layer. Laboratory results also revealed sufficient air permeability of the soil materials (TS-F and SS-Z) placed in lysimeter C. However, at higher compaction density SS-Z became impermeable at 100% WHC. Methane emissions from the reference lysimeter with the smaller substrate cover (12-52 g CH(4)/m(2)d) were significantly higher than fluxes from the other lysimeters (0-19 g CH(4)/m(2)d) during in situ aeration. Regarding water balance, lysimeters covered with compost and compost-sand mixture, showed the lowest leachate rate (18-26% of the precipitation) due to the high water holding capacity and more favourable plant growth conditions compared to the lysimeters with mineral, more cohesive, soil covers (27-45% of the precipitation). On the basis of these results, the authors suggest a layered top cover system using both compost material as well as mineral soil in order to support active low-pressure aeration. Conventional soil materials with lower permeability may be used on top of the landfill body for a more uniform aeration of the waste due to an increased resistance to vertical gas flow. A compost cover may be built on top of the soil cover underlain by a gas distribution layer to improve methane oxidation rates and minimise water infiltration. By planting vegetation with a high transpiration rate, the leachate amount emanating from the landfill could be further minimised. The suggested design may be particularly suitable in combination with intermittent in situ aeration, in the later stage of an aeration measure, or at very small sites and shallow deposits. The top cover system could further regulate water infiltration into the landfill and mitigate residual CH(4) emissions, even beyond the time of active aeration. PMID:22749719

  6. Effects of sanitary landfill leachate on some soil chemical properties

    SciTech Connect

    Winant, W.M.; Menser, H.A.; Bennett, O.L.

    1981-09-01

    The treatment of leachate from sanitary landfills has become a serious problem for many communities because of rising concern for water quality and increased use of landfills for disposal of solid waste. The objective of this research was to test the value of using soils to decontaminate waste water from a landfill. Approximately 100 cm of leachate from a sanitary landfill was applied over a 6-month period, after which soil samples were collected to a depth of 60 cm. Ammonium acetate was used to extract Ca, Mg, Na, K, Mn, Fe, Zn, and Sr, while P was extracted with a dilute double acid. At a soil depth of 0 to 5 cm Ca, Mg, Na, K, and Sr levels of ammonium acetate extracts markedly increased, while leachate irrigation did not significantly change Fe, Zn, P, and Kjeldahl N concentrations. Leachate irrigation increased soil pH from 4.7 to 5.8 at the 0- to 5-cm depth and from 4.5 to 5.7 at the 15- to 30-cm depth. Most elements were attenuated to some extent by the soil, but lime and fertilizer addition did little to influence soil absorptive capacity.

  7. Effect of intermediate soil cover on municipal solid waste decomposition.

    PubMed

    Márquez-Benavides, L; Watson-Craik, I

    2003-01-01

    A complex series of chemical and microbiological reactions is initiated with the burial of refuse in a sanitary landfill. At the end of each labour day, the municipal solid wastes (MSW) are covered with native soil (or an alternative material). To investigate interaction between the intermediate cover and the MSW, five sets of columns were set up, one packed with refuse only, and four with a soil-refuse mixture (a clay loam, an organic-rich peaty soil, a well limed sandy soil and a chalky soil). The anaerobic degradation over 6 months was followed in terms of leachate volatile fatty acids, chemical oxygen demand, pH and ammoniacal-N performance. Results suggest that the organic-rich peaty soil may accelerate the end of the acidogenic phase. Clay appeared not to have a significant effect on the anaerobic degradation process. PMID:14531450

  8. Alternative Landfill Cover and Monitoring Systems for Landfills in Arid Environments

    SciTech Connect

    S. E. Rawlinson

    2002-09-01

    In December 2000, a performance monitoring facility was constructed adjacent to the mixed waste disposal unit U-3ax/bl at the Area 3 Radioactive Waste Management Site at the Nevada Test Site. This facility consists of eight drainage lysimeters measuring 10 feet in diameter, 8 feet deep, and backfilled with native soil. The lysimeters have three different surface treatments: two were left bare, two were revegetated with native species, and two were allowed to revegetate with invader species (two are reserved for future studies). The lysimeters are instrumented with an array of soil water content and soil water potential sensors and have sealed bottoms so that any drainage can be measured. All sensors are working properly and indicate that the bare lysimeters are the wettest, as expected. The vegetated lysimeters, both seeded and those allowed to revegetate with invader species, are significantly drier than the bare cover treatments. No drainage has occurred in any of the lysimeters. The Accelerated Site Technology Deployment program under the U.S. Department of Energy's Office of Science and Technology provided the funding for this project with the objective of reducing the uncertainty associated with the performance of monolayer-evapotranspiration waste covers in arid regions such as the one deployed at U-3ax/bl.

  9. USE OF ALTERNATIVE MATERIALS FOR DAILY COVER AT MUNICIPAL SOLID WASTE LANDFILLS

    EPA Science Inventory

    The current (ca. 1992) applicability of alternative materials as daily cover at landfills was assessed from an operational, performance, environmental, and economic perspective. he types of products and materials considered included commercially available foams, spray-ons and geo...

  10. Deployment of an alternative cover and final closure of the Mixed Waste Landfill, Sandia National Laboratories, Albuquerque, New Mexico.

    SciTech Connect

    Peace, Gerald L.; Goering, Timothy James; McVey, Michael David (GRAM, Inc., Albuquerque, NM); Borns, David James

    2003-06-01

    An alternative cover design consisting of a monolithic layer of native soil is proposed as the closure path for the Mixed Waste Landfill at Sandia National Laboratories, New Mexico. The proposed design would rely upon soil thickness and evapotranspiration to provide long-term performance and stability, and would be inexpensive to build and maintain. The proposed design is a 3-ft-thick, vegetated soil cover. The alternative cover meets the intent of RCRA Subtitle C regulations in that: (a) water migration through the cover is minimized; (b) maintenance is minimized by using a monolithic soil layer; (c) cover erosion is minimized by using erosion control measures; (d) subsidence is accommodated by using a ''soft'' design; and (e) the permeability of the cover is less than or equal to that of natural subsurface soil present. Performance of the proposed cover is integrated with natural site conditions, producing a ''system performance'' that will ensure that the cover is protective of human health and the environment. Natural site conditions that will produce a system performance include: (a) extremely low precipitation and high potential evapotranspiration; (b) negligible recharge to groundwater; (c) an extensive vadose zone; (d) groundwater approximately 500 ft below the surface; and (e) a versatile, native flora that will persist indefinitely as a climax ecological community with little or no maintenance.

  11. Two-year performance by evapotranspiration covers for municipal solid waste landfills in northwest Ohio.

    PubMed

    Barnswell, Kristopher D; Dwyer, Daryl F

    2012-12-01

    Evapotranspiration (ET) covers have gained interest as an alternative to conventional covers for the closure of municipal solid waste (MSW) landfills because they are less costly to construct and are expected to have a longer service life. Whereas ET covers have gained acceptance in arid and semi-arid regions (defined by a precipitation (P) to potential evapotranspiration (PET) ratio less than 0.75) by meeting performance standards (e.g. rate of percolation), it remains unclear whether they are suitable for humid regions (P:PET greater than 0.75). The goal of this project is to extend their application to northwest Ohio (P:PET equals 1.29) by designing covers that produce a rate of percolation less than 32 cm yr(-1), the maximum acceptable rate by the Ohio Environmental Protection Agency (OEPA). Test ET covers were constructed in drainage lysimeters (1.52 m diameter, 1.52 m depth) using dredged sediment amended with organic material and consisted of immature (I, plants seeded onto soil) or mature (M, plants transferred from a restored tall-grass prairie) plant mixtures. The water balance for the ET covers was monitored from June 2009 to June 2011, which included measured precipitation and percolation, and estimated soil water storage and evapotranspiration. Precipitation was applied at a rate of 94 cm yr(-1) in the first year and at rate of 69 cm yr(-1) in the second year. During the first year, covers with the M plant mixture produced noticeably less percolation (4 cm) than covers with the I plant mixture (17 cm). However, during the second year, covers with the M plant mixture produced considerably more percolation (10 cm) than covers with the I plant mixture (3 cm). This is likely due to a decrease in the aboveground biomass for the M plant mixture from year 1 (1008 g m(-2)) to year 2 (794 g m(-2)) and an increase for the I plant mixture from year 1 (644 g m(-2)) to year 2 (1314 gm(-2)). Over the 2-year period, the mean annual rates of percolation for the covers with the M and I plant mixtures were 7 and 8 cm yr(-1), which are below the OEPA standard. The results suggest the application of ET covers be extended to northwest Ohio and other humid regions. PMID:22878048

  12. Water balance relationships in four alternative cover designs for radioactive and mixed waste landfills

    SciTech Connect

    Warren, R.W.; Hakonson, T.E.; Trujillo, G.

    1994-08-01

    Preliminary results are presented from a field study to evaluate the relative hydrologic performance of various landfill capping technologies installed by the Los Alamos National Laboratory at Hill Air Force Base, Utah. Four cover designs (two Los Alamos capillary barrier designs, one modified EPA RCRA design, and one conventional design) were installed in large lysimeters instrumented to monitor the fate of natural precipitation between 01 January 1990 and 20 September 1993. After 45 months of study, results showed that the cover designs containing barrier layers were effective in reducing deep percolation as compared to a simple soil cap design. The RCRA cover, incorporating a clay hydraulic barrier, was the most effective of all cover designs in controlling percolation but was not 100% effective. Over 90% of all percolation and barrier lateral flow occurred during the months of February through May of each year, primarily as a result of snow melt, early spring rains and low evapotranspiration. Gravel mulch surface treatments (70--80% coverage) were effective in reducing runoff and erosion. The two plots receiving gravel mulch treatments exhibited equal but enhanced amounts of evapotranspiration despite the fact that one plot was planted with additional shrubs.

  13. Assessing the environmental impact of ashes used in a landfill cover construction.

    PubMed

    Travar, I; Lidelöw, S; Andreas, L; Tham, G; Lagerkvist, A

    2009-04-01

    Large amounts of construction materials will be needed in Europe in anticipation for capping landfills that will be closed due to the tightening up of landfill legislation. This study was conducted to assess the potential environmental impacts of using refuse derived fuel (RDF) and municipal solid waste incineration (MSWI) ashes as substitutes for natural materials in landfill cover designs. The leaching of substances from a full-scale landfill cover test area built with different fly and bottom ashes was evaluated based on laboratory tests and field monitoring. The water that drained off above the liner (drainage) and the water that percolated through the liner into the landfill (leachate) were contaminated with Cl(-), nitrogen and several trace elements (e.g., As, Cu, Mo, Ni and Se). The drainage from layers containing ash will probably require pre-treatment before discharge. The leachate quality from the ash cover is expected to have a minor influence on overall landfill leachate quality because the amounts generated from the ash covers were low, <3-30l (m(2)yr)(-1). Geochemical modelling indicated that precipitation of clay minerals and other secondary compounds in the ash liner was possible within 3 years after construction, which could contribute to the retention of trace elements in the liner in the long term. Hence, from an environmental view point, the placement of ashes in layers above the liner is more critical than within the liner. PMID:19081235

  14. Use of the time domain reflectrometry in hydraulic studies of multilayered landfill covers for closure of waste landfills at Los Alamos, New Mexico

    SciTech Connect

    Nyhan, J.W.; Schofield, T.G.; Martin, C.E.

    1994-04-01

    The Los Alamos National Laboratory examined water balance relationships for four different landfill cover designs containing hydraulic and capillary engineered barriers. Seepage is being evaluated as a function of slope length for each plot, as well as interflow, runoff, and precipitation, using an automated water flow datalogging system that routinely collects hourly data. Soil water content within these 16 field plots has been routinely monitored four times a day since November 1991 using time domain reflectrometry techniques with an automated and multiplexed measurement system. Volumetric water content is measured with a pair of 60-cm-long waveguides at each of 212 locations. One set of waveguides was emplaced vertically in four locations in every soil layer to determine soil water inventory in each field plot. A second set of waveguides was emplaced horizontally in several soil layers to provide a more detailed picture of soil water dynamics close to soil layer interfaces. Field data is presented showing pulses of soil water moving through the soil and engineered barriers with high temporal and spatial resolution.

  15. Toxicity Assessment of Contaminated Soils of Solid Domestic Waste Landfill

    NASA Astrophysics Data System (ADS)

    Pasko, O. A.; Mochalova, T. N.

    2014-08-01

    The paper delivers the analysis of an 18-year dynamic pattern of land pollutants concentration in the soils of a solid domestic waste landfill. It also presents the composition of the contaminated soils from different areas of the waste landfill during its operating period. The authors calculate the concentrations of the following pollutants: chrome, nickel, tin, vanadium, lead, cuprum, zinc, cobalt, beryllium, barium, yttrium, cadmium, arsenic, germanium, nitrate ions and petrochemicals and determine a consistent pattern of their spatial distribution within the waste landfill area as well as the dynamic pattern of their concentration. Test-objects are used in experiments to make an integral assessment of the polluted soil's impact on living organisms. It was discovered that the soil samples of an animal burial site are characterized by acute toxicity while the area of open waste dumping is the most dangerous in terms of a number of pollutants. This contradiction can be attributed to the synergetic effect of the polluted soil, which accounts for the regularities described by other researchers.

  16. Steel slag used in landfill cover liners: laboratory and field tests.

    PubMed

    Herrmann, Inga; Andreas, Lale; Diener, Silvia; Lind, Lotta

    2010-12-01

    Stricter rules for landfilling within the EU have led to the closure of many landfills and a need for large amounts of cover liner materials. Therefore, the potential utilization of mixtures of electric arc furnace slag (EAFS) and ladle slag (LS), which are currently deposited in landfills, as a material for use as landfill liner was investigated. Laboratory analyses showed the mixtures to have similar compression strength to that of high-strength concrete and low hydraulic conductivity (< 10(-11) m s(-1) in some cases). However, both their hydraulic conductivity and compaction properties were strongly affected by the time between adding water to the mixtures and compacting them (tests showed that a delay of 24 h can lead to an increase in hydraulic conductivity, so it should be compacted as soon as possible after mixing the material with water). In addition, the performance of a cover liner constructed using EAFS and LS was studied in a 2-year field trial on a landfill for municipal solid waste, in which the average amount of leachate collected from ten lysimeters was only 27 L m(-2) year(-1), easily meeting Swedish criteria for the permeability of covers on non-hazardous waste landfills (? 50 L m(-2) year(-1)). Thus, the material seems to have promising potential for use in barrier constructions. PMID:20421245

  17. Field Performance Of A Compacted Clay Landfill Final Cover At A Humid Site

    EPA Science Inventory

    A study was conducted in southern Georgia, USA, to evalaute how the hydraulic properties of the compacted clay barrier layer in a final landfill cover changed over a 4-year service life. The cover was part of a test section constructed in a large drainage lysimeter that allowed ...

  18. A RULE-BASED SYSTEM FOR EVALUATING FINAL COVERS FOR HAZARDOUS WASTE LANDFILLS

    EPA Science Inventory

    This chapter examines how rules are used as a knowledge representation formalism in the domain of hazardous waste management. A specific example from this domain involves performance evaluation of final covers used to close hazardous waste landfills. Final cover design and associ...

  19. Landfill leachate clogging of geotextile (and soil) filters

    SciTech Connect

    Koerner, R.M.; Koerner, G.R.

    1991-07-01

    The primary leachate collection system of most solid waste landfills contains a filter layer which has historically been a granular soil. Recently, however, various types of geotextile filters have been used to replace the natural soil filters. A project using six different landfill leachates and aimed at investigating the functioning of different geotextile filters is the focus of this 36 month long study. The initial 12 months, referred to as Phase 1, investigated flow rates in various filters under aerobic conditions at six different landfill sites using the site-specific leachates. The study inadvertently found that the overlying granular soil clogged as much as the geotextile filter that was located downstream. The effects of different types and styles of geotextiles was generally masked by the upstream soil clogging. An important finding in this task was the biodegradation of the geotextiles was not evidenced and was concluded to be a non-issue. The subsequent 24 months of study, referred to as Phase 2(a), led to the development of a vastly improved flow rate monitoring device. In a separate task, referred to as Phase 2(b) and conducted simultaneously with Phase 2(a), biocide treated geosynthetics were utilized at the two sites with the most aggressive leachates. While the biocides may have been effective in killing microorganisms, the remnants were as troublesome as the viable bacteria in creating subsequent clogging.

  20. Landfill cover revegetation using organic amendments and cobble mulch in the arid southwest

    SciTech Connect

    AGUILAR,RICHARD; DWYER,STEPHEN F.; REAVIS,BRUCE A.; NEWMAN,GRETCHEN CARR; LOFTIN,SAMUEL R.

    2000-02-01

    Cobble mulch and composted biosolids, greenwaste, and dairy manure were added to arid soil in an attempt to improve plant establishment and production, minimize erosion, increase evapotranspiration, and reduce leaching. Twenty-four plots (10 x 10 m) were established in a completely randomized block design (8 treatments, 3 plots per treatment). Treatments included (1) non-irrigated control, (2) irrigated control, (3) non-irrigated greenwaste compost (2.5 yd{sup 3} per plot), (4) irrigated greenwaste compost (5 yd{sup 3} per plot), (5) non-irrigated biosolids compost (2.5 yd{sup 3} per plot), (6) irrigated biosolids compost (5 yd{sup 3} per plot), (7) cobble-mulch, and (8) non-irrigated dairy manure compost (2.5 yd{sup 3} per plot). Soil samples were collected from each plot for laboratory analyses to assess organic matter contents, macro-nutrient levels and trace metal contents, and nitrogen mineralization potential. All plots were seeded similarly with approximately equal portions of cool and warm season native grasses. The organic composts (greenwaste, biosolids, dairy manure) added to the soils substantially increased soil organic matter and plant nutrients including total nitrogen and phosphorus. However, the results of a laboratory study of the soils' nitrogen mineralization potential after the application of the various composts showed that the soil nitrogen-supplying capability decreased to non-amended soil levels by the start of the second growing season. Thus, from the standpoint of nitrogen fertilizer value, the benefits of the organic compost amendments appear to have been relatively short-lived. The addition of biosolids compost, however, did not produce significant changes in the soils' copper, cadmium, lead, and zinc concentrations and thus did not induce adverse environmental conditions due to excessive heavy metal concentrations. Supplemental irrigation water during the first and second growing seasons did not appear to increase plant biomass production in the irrigated control plots over that produced in the non-irrigated control plots. This surprising result was probably due to the cumulative effects of other factors that influenced the initial establishment and production of plants in the plots (e.g., plant species competition, seed germination delay times, differences in nutrient release and availability). Variation within individual plots, and among the three replicate plots associated with each treatment, rendered many of the recorded differences in vegetation establishment and production statistically insignificant. However, after two complete growing seasons the highest total plant foliar cover and the greatest biomass production and plant species diversity occurred in the cobble-mulched plots. These results suggest that cobble-mulch may be the desired amendment in re-vegetated arid landfill covers if the principal objectives are to quickly establish vegetation cover, stabilize the site from erosion, and increase water usage by plants, thereby reducing the potential for leaching and contaminant movement from the landfill's waste-bearing zone.

  1. Landfills in the year 2000

    SciTech Connect

    Glebs, B. )

    1994-03-01

    The 21st century landfill will have the proper public and customer image from the environmental standpoint. The landfill of the 21st century will provide diverse services right at the landfill. You will not only have burial of waste, but a bioremediation pad for handling certain petro-chemical soils and a reuse area for concrete and rubble. Landfills will reuse special wastes. The industry now has more than seven specialized industrial wastes approved for landfill cover. So, instead of spending money for landfill cover or alternative cover like foam, landfills will actually get paid for the landfill cover. The landfill of the 21st century will have some level of recycling and composting. The sites will broaden their service base to make sure that the customer will be able to bring the wide variety of waste to one place. All of this technology will be designed to function at the landfill to keep waste out of the landfill. From a regulatory standpoint, obviously 21st century landfills will exceed all of the standards. It will be a given that the landfill will have liners, leachate collection, leachate treatment, and gas recovery and, probably, reuse. The 21st century landfill will receive a very different waste type. It will have less municipal solid waste and a greater volume of special waste-compatible, nonhazardous waste.

  2. Cover crops to enhance soil biological activity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cover crops can be an important component of conservation agricultural systems in the eastern USA. This presentation summarizes some of the benefits derived from cover crops, how cover crops impact soil biological activity, and how soil biological activity can be used to assess the sustainability o...

  3. Two-year performance by evapotranspiration covers for municipal solid waste landfills in northwest Ohio

    SciTech Connect

    Barnswell, Kristopher D.; Dwyer, Daryl F.

    2012-12-15

    Highlights: Black-Right-Pointing-Pointer All ET covers produced rates of percolation less than 32 cm yr{sup -1}, the maximum allowable rate by the Ohio EPA. Black-Right-Pointing-Pointer Dredged sediment provided sufficient water storage and promoted growth by native plant species. Black-Right-Pointing-Pointer Native plant mixtures attained acceptable rates of evapotranspiration throughout the growing season. - Abstract: Evapotranspiration (ET) covers have gained interest as an alternative to conventional covers for the closure of municipal solid waste (MSW) landfills because they are less costly to construct and are expected to have a longer service life. Whereas ET covers have gained acceptance in arid and semi-arid regions (defined by a precipitation (P) to potential evapotranspiration (PET) ratio less than 0.75) by meeting performance standards (e.g. rate of percolation), it remains unclear whether they are suitable for humid regions (P:PET greater than 0.75). The goal of this project is to extend their application to northwest Ohio (P:PET equals 1.29) by designing covers that produce a rate of percolation less than 32 cm yr{sup -1}, the maximum acceptable rate by the Ohio Environmental Protection Agency (OEPA). Test ET covers were constructed in drainage lysimeters (1.52 m diameter, 1.52 m depth) using dredged sediment amended with organic material and consisted of immature (I, plants seeded onto soil) or mature (M, plants transferred from a restored tall-grass prairie) plant mixtures. The water balance for the ET covers was monitored from June 2009 to June 2011, which included measured precipitation and percolation, and estimated soil water storage and evapotranspiration. Precipitation was applied at a rate of 94 cm yr{sup -1} in the first year and at rate of 69 cm yr{sup -1} in the second year. During the first year, covers with the M plant mixture produced noticeably less percolation (4 cm) than covers with the I plant mixture (17 cm). However, during the second year, covers with the M plant mixture produced considerably more percolation (10 cm) than covers with the I plant mixture (3 cm). This is likely due to a decrease in the aboveground biomass for the M plant mixture from year 1 (1008 g m{sup -2}) to year 2 (794 g m{sup -2}) and an increase for the I plant mixture from year 1 (644 g m{sup -2}) to year 2 (1314 g m{sup -2}). Over the 2-year period, the mean annual rates of percolation for the covers with the M and I plant mixtures were 7 and 8 cm yr{sup -1}, which are below the OEPA standard. The results suggest the application of ET covers be extended to northwest Ohio and other humid regions.

  4. Reuse of MSWI bottom ash mixed with natural sodium bentonite as landfill cover material.

    PubMed

    Puma, Sara; Marchese, Franco; Dominijanni, Andrea; Manassero, Mario

    2013-06-01

    The research described in this study had the aim of evaluating the reuse of incinerator slag, mixed with sodium bentonite, for landfill capping system components. A characterization was performed on pure bottom ash (BA) samples from an incinerator in the north of Italy. The results show that the BA samples had appropriate properties as covers. The compacted dry unit weight of the studied BA (16.2 kN m(-3)) was lower than the average value that characterizes most conventional fill materials and this can be considered advantageous for landfill cover systems, since the fill has to be placed on low bearing capacity ground or where long-term settlement is possible. Moreover, direct shear tests showed a friction angle of 43°, corresponding to excellent mechanical characteristics that can be considered an advantage against failure. The hydraulic conductivity tests indicated a steady-state value of 8 × 10(-10) m s(-1) for a mixture characterized by a bentonite content by weight of 10%, which was a factor 10 better than required by Italian legislation on landfill covers. The results from a swell index test indicated that fine bentonite swelled, even when divalent cations were released by the BA. The leaching behaviour of the mixture did not show any contamination issues and was far better than obtained for the pure BA. Thus, the BA-bentonite mixture qualified as a suitable material for landfill cover in Italy. Moreover, owing to the low release of toxic compounds, the proposed cover system would have no effect on the leachate quality in the landfill. PMID:23478909

  5. Soil chemistry and pollution study of a closed landfill site at Ampar Tenang, Selangor, Malaysia.

    PubMed

    Mohd Adnan, Siti Nur Syahirah Binti; Yusoff, Sumiani; Piaw, Chua Yan

    2013-06-01

    A total of 20 landfills are located in State of Selangor, Malaysia. This includes the Ampar Tenang landfill site, which was closed on 26 January 2010. It was reported that the landfill has been upgraded to a level I type of sanitary classification. However, the dumpsite area is not being covered according to the classification. In addition, municipal solid waste was dumped directly on top of the unlined natural alluvium formation. This does not only contaminate surface and subsurface soils, but also initiates the potential risk of groundwater pollution. Based on previous studies, the Ampar Tenang soil has been proven to no longer be capable of preventing pollution migration. In this study, metal concentrations of soil samples up to 30 m depth were analyzed based on statistical analysis. It is very significant because research of this type has not been carried out before. The subsurface soils were significantly polluted by arsenic (As), lead (Pb), iron (Fe), copper (Cu) and aluminium (Al). As and Pb exceeded the safe limit values of 5.90 mg/kg and 31.00 mg/kg, respectively, based on Provincial Sediment Quality Guidelines for Metals and the Interim Sediment Quality Values. Furthermore, only Cu concentrations showed a significantly decreasing trend with increasing depth. Most metals were found on clay-type soils based on the cluster analysis method. Moreover, the analysis also differentiates two clusters: cluster I-Pb, As, zinc, Cu, manganese, calcium, sodium, magnesium, potassium and Fe; cluster II-Al. Different clustering may suggest a different contamination source of metals. PMID:23528999

  6. A process-based inventory model for landfill CH4 emissions inclusive of seasonal soil microclimate and CH4 oxidation

    NASA Astrophysics Data System (ADS)

    Spokas, K.; Bogner, J.; Chanton, J.

    2011-12-01

    We have developed and field-validated an annual inventory model for California landfill CH4 emissions that incorporates both site-specific soil properties and soil microclimate modeling coupled to 0.5° scale global climatic models. Based on 1-D diffusion, CALMIM (California Landfill Methane Inventory Model) is a freely available JAVA tool which models a typical annual cycle for CH4 emissions from site-specific daily, intermediate, and final landfill cover designs. Literature over the last decade has emphasized that the major factors controlling emissions in these highly managed soil systems are the presence or absence of engineered gas extraction, gaseous transport rates as affected by the thickness and physical properties of cover soils, and methanotrophic CH4 oxidation in cover materials as a function of seasonal soil microclimate. Moreover, current IPCC national inventory models for landfill CH4 emissions based on theoretical gas generation have high uncertainties and lack comprehensive field validation. This new approach, which is compliant with IPCC "Tier III" criteria, has been field-validated at two California sites (Monterey County; Los Angeles County), with limited field validation at three additional California sites. CALMIM accurately predicts soil temperature and moisture trends with emission predictions within the same order of magnitude as field measurements, indicating an acceptable initial model comparison in the context of published literature on measured CH4 emissions spanning 7 orders of magnitude. In addition to regional defaults for inventory purposes, CALMIM permits user-selectable parameters and boundary conditions for more rigorous site-specific applications where detailed CH4 emissions, meteorological, and soil microclimate data exist.

  7. Ambient air monitoring of the beneficial use of municipal waste combustor (MWC) ash as daily landfill cover

    SciTech Connect

    Magee, B.H.; Miller, A.C.; Hahn, J.L.; Jones, C.M.

    1997-12-01

    This paper summarizes Human Health Risk Assessments of the proposed use of combined ash from the H-Power municipal waste combustor (MWC) in two beneficial uses: (1) Landfill Daily Cover for the Waimanalo Gulch Sanitary Landfill in Ewa, O`ahu, Hawaii, which is operated by Waste Management of Hawaii, Inc. for the City and County of Honolulu and (2) Landfill Final Cover, a component in the final cover of the Waipahu landfill, in Waipahu, O`ahu, Hawaii. The human health risk assessment represents one phase of a larger project involving the investigation of several potential uses of H-Power MWC ash as alternatives to the current practice of disposal in a lined monofill located at the Waimanalo Gulch Sanitary Landfill. The ash consists of approximately 70% bottom ash and 30% fly ash from the MWC, hereafter referred to as H-Power combined ash. At this time, three alternative uses of H-Power combined ash have been identified: The first option consists of using H-Power combined ash as a component in the final cover in the closure of the Waipahu Landfill; the second option consists of using H-Power combined ash as daily cover at the Waimanalo Gulch Sanitary Landfill; and, the third option consists of mixing H-Power combined ash into aggregate to be used in roadway paving material.

  8. Future landfill emissions and the effect of final cover installation--a case study.

    PubMed

    Laner, David; Fellner, Johann; Brunner, Paul H

    2011-07-01

    Municipal solid waste (MSW) landfills are potential long-term sources of emissions. Hence, they need to be managed after closure until they do not pose a threat to humans or the environment. The case study on the Breitenau MSW landfill was performed to evaluate future emission levels for this site and to illustrate the effect of final cover installation with respect to long-term environmental risks. The methodology was based on a comprehensive assessment of the state of the landfill and included analysis of monitoring data, investigations of landfilled waste, and an evaluation of containment systems. A model to estimate future emission levels was established and site-specific predictions of leachate emissions were presented based on scenario analysis. The results are used to evaluate the future pollution potential of the landfill and to compare different aftercare concepts in view of long-term emissions. As some leachable substances became available for water flow during cover construction due to a change in the water flow pattern of the waste, a substantial increase in leachate concentrations could be observed at the site (e.g. concentrations of chloride increased from 200 to 800 mg/l and of ammonia-nitrogen from 140 to about 500 mg/l). A period of intensive flushing before the final cover installation could have reduced the amount of leachable substances within the landfill body and rapidly decreased the leachate concentrations to 11 mg Cl/l and 79 mg NH(4)-N/l within 50 years. Contrarily, the minimization of water infiltration is associated with leachate concentrations in a high range for centuries (above 400 mg Cl/l and 200 mg NH(4)-N/l) with low concomitant annual emission loads (below 12 kg/year of Cl or 9 kg/year of NH(4)-N, respectively). However, an expected gradual decrease of barrier efficiency over time would be associated with higher emission loads of 50 kg of chloride and 30 kg of ammonia-nitrogen at the maximum, but a faster decrease of leachate concentration levels. PMID:21421299

  9. Methane flux and oxidation at two types of intermediate landfill covers

    SciTech Connect

    Abichou, Tarek . E-mail: abichou@eng.fsu.edu; Chanton, Jeffery; Powelson, David; Fleiger, Jill; Escoriaza, Sharon; Lei, Yuan; Stern, Jennifer

    2006-07-01

    Methane emissions were measured on two areas at a Florida (USA) landfill using the static chamber technique. Because existing literature contains few measurements of methane emissions and oxidation in intermediate cover areas, this study focused on field measurement of emissions at 15-cm-thick non-vegetated intermediate cover overlying 1-year-old waste and a 45-cm-thick vegetated intermediate cover overlying 7-year-old waste. The 45 cm thick cover can also simulate non-engineered covers associated with older closed landfills. Oxidation of the emitted methane was evaluated using stable isotope techniques. The arithmetic means of the measured fluxes were 54 and 22 g CH{sub 4} m{sup -2} d{sup -1} from the thin cover and the thick cover, respectively. The peak flux was 596 g m{sup -2} d{sup -1} for the thin cover and 330 g m{sup -2} d{sup -1} for the thick cover. The mean percent oxidation was significantly greater (25%) at the thick cover relative to the thin cover (14%). This difference only partly accounted for the difference in emissions from the two sites. Inverse distance weighing was used to describe the spatial variation of flux emissions from each cover type. The geospatial mean flux was 21.6 g m{sup -2} d{sup -1} for the thick intermediate cover and 50.0 g m{sup -2} d{sup -1} for the thin intermediate cover. High emission zones in the thick cover were fewer and more isolated, while high emission zones in the thin cover were continuous and covered a larger area. These differences in the emission patterns suggest that different CH{sub 4} mitigation techniques should be applied to the two areas. For the thick intermediate cover, we suggest that effective mitigation of methane emissions could be achieved by placement of individualized compost cells over high emission zones. Emissions from the thin intermediate cover, on the other hand, can be mitigated by placing a compost layer over the entire area.

  10. CHEMICAL AND PHYSICAL EFFECTS OF MUNICIPAL LANDFILLS ON UNDERLYING SOILS AND GROUNDWATER

    EPA Science Inventory

    Three municipal landfill sites in the eastern and central United States were studied to determine the effects of the disposal facilities on surrounding soils and groundwater. Borings were made up the groundwater gradient, down the groundwater gradient and through the landfill. So...

  11. Winter cover biomass production and soil penetrability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Winter cover crops can benefit production systems in the southeastern US. Winter cover crops, such as rye (Secale cereale) can reduce weed pressure, increase water infiltration, and improve soil quality over a long period of time. Although several studies have focused on the effects of having a wi...

  12. PREDICTION/MITIGATION OF SUBSIDENCE DAMAGE TO HAZARDOUS WASTE LANDFILL COVERS

    EPA Science Inventory

    Characteristics of Resource Conservation and Recovery Act hazardous waste landfills and of landfilled hazardous wastes have been described to permit development of models and other analytical techniques for predicting, reducing, and preventing landfill settlement and related cove...

  13. Global climate changes and the soil cover

    NASA Astrophysics Data System (ADS)

    Kudeyarov, V. N.; Demkin, V. A.; Gilichinskii, D. A.; Goryachkin, S. V.; Rozhkov, V. A.

    2009-09-01

    The relationships between climate changes and the soil cover are analyzed. The greenhouse effect induced by the rising concentrations of CO2, CH4, N2O, and many other trace gases in the air has been one of the main factors of the global climate warming in the past 30-40 years. The response of soils to climate changes is considered by the example of factual data on soil evolution in the dry steppe zone of Russia. Probable changes in the carbon cycle under the impact of rising CO2 concentrations are discussed. It is argued that this rise may have an effect of an atmospheric fertilizer and lead to a higher productivity of vegetation, additional input of organic residues into the soils, and activation of soil microflora. Soil temperature and water regimes, composition of soil gases, soil biotic parameters, and other dynamic soil characteristics are most sensitive to climate changes. For the territory of Russia, in which permafrost occupies more than 50% of the territory, the response of this highly sensitive natural phenomenon to climate changes is particularly important. Long-term data on soil temperatures at a depth of 40 cm are analyzed for four large regions of Russia. In all of them, except for the eastern sector of Russian Arctic, a stable trend toward the rise in the mean annual soil temperature. In the eastern sector (the Verkhoyansk weather station), the soil temperature remains stable.

  14. Effects of substrate induced respiration on the stability of bottom ash in landfill cover environment.

    PubMed

    Ilyas, A; Lovat, E; Persson, K M

    2014-12-01

    The municipal solid waste incineration bottom ash is being increasingly used to construct landfill covers in Sweden. In post-closure, owing to increased cover infiltration, the percolating water can add external organic matter to bottom ash. The addition and subsequent degradation of this external organic matter can affect metal mobility through complexation and change in redox conditions. However, the impacts of such external organic matter addition on bottom ash stability have not been fully evaluated yet. Therefore, the objective of this study was to evaluate the impact of external organic matter on bottom ash respiration and metal leaching. The samples of weathered bottom ash were mixed with oven dried and digested wastewater sludge (1%-5% by weight). The aerobic respiration activity (AT4), as well as the leaching of metals, was tested with the help of respiration and batch leaching tests. The respiration and heavy metal leaching increased linearly with the external organic matter addition. Based on the results, it was concluded that the external organic matter addition would negatively affect the quality of landfill cover drainage. PMID:25395160

  15. A numerical study of soil cover performance.

    PubMed

    Yanful, Ernest K; Morteza Mousavi, S; De Souza, Lin-Pei

    2006-10-01

    In the investigation of soil cover design options for final decommissioning of reactive mine waste, it is often necessary to analyze or predict the anticipated cover performance as a function of the cost of implementation, which is governed by the type, number and thickness of the layers in the cover system. An example of such investigation is presented in this study where one-dimensional evaporation from hypothetical moisture-retaining cover systems is simulated to assess the influence of several cover properties and hydrogeologic parameters on performance. The commercially available transient flow model, SoilCover, was used to compute suction and water content profiles for different cover design scenarios. The predicted water content profile and porosity of layers were then used to estimate the oxygen diffusion coefficients of the various layers. The oxygen diffusion coefficients were used to estimate oxygen flux through the cover systems. The oxygen flux was, in turn, related to the maximum acid flux. The studied cover and hydrogeologic parameters included soil type, thickness of barriers, and water table elevation. Two types of infiltration and oxygen barrier and two types of capillary layer with different thicknesses were studied. The water table was either kept constant at the base of the waste (tailings) or dropped by 0.5, 1, 2, and 3m over 120 days. The results showed that the relationship between water table depression and the thickness of capillary layers, on one hand, and desaturation of the infiltration and oxygen barrier, on the other, is not linear. Relationships between oxygen flux and barrier thickness and between cost increase and performance improvement of the studied cover systems are presented. Finally, a method that outlines steps for site-specific and economically feasible design of multi-layer cover systems is introduced. PMID:16556481

  16. Soils and the soil cover of the Valley of Geysers

    NASA Astrophysics Data System (ADS)

    Kostyuk, D. N.; Gennadiev, A. N.

    2014-06-01

    The results of field studies of the soil cover within the tourist part of the Valley of Geysers in Kamchatka performed in 2010 and 2011 are discussed. The morphology of soils, their genesis, and their dependence on the degree of hydrothermal impact are characterized; the soil cover patterns developing in the valley are analyzed. On the basis of the materials provided by the Kronotskii Biospheric Reserve and original field data, the soil map of the valley has been developed. The maps of vegetation conditions, soil temperature at the depth of 15 cm, and slopes of the surface have been used for this purpose together with satellite imagery and field descriptions of reference soil profiles. The legend to the soil map includes nine soil units and seven units of parent materials and their textures. Soil names are given according to the classification developed by I.L. Goldfarb (2005) for the soils of hydrothermal fields. The designation of soil horizons follows the new Classification and Diagnostic System of Russian Soils (2004). It is suggested that a new horizon—a thermometamorphic horizon TRM—can be introduced into this system by analogy with other metamorphic (transformed in situ) horizons distinguished in this system. This horizon is typical of the soils partly or completely transformed by hydrothermal impacts.

  17. Snow cover and soil moisture in mountains

    NASA Astrophysics Data System (ADS)

    Wever, N.; Lehning, M.

    2012-04-01

    Soil moisture is an important parameter of the climate system. It constrains evapotranspiration of plants and it functions as a storage of water, giving it an economic value, e.g. for agriculture. Furthermore, soil moisture is an important factor for predicting flood risk. In mountainous areas with a seasonal snow cover, the spatial distribution of snow depth is strongly influencing the spatial variation of soil moisture. To assess potential flooding situations during snow melt and rain on snow events in particular but for any heavy precipitation event in the mountains, it is important to understand the influence of the snow cover on soil status with respect to liquid and solid water. Only if this is known, the reaction of the soil i.e. amount of runoff, storage or melt, on additional water input can be assessed. For an operational assessment of the soil moisture state in the Swiss Alps at 140 measurement sites for snow and avalanche forecasting (IMIS network), the SNOWPACK model has been extended with a soil module, solving the Richards equation for the matrix flow. The modelling is validated with vertical profile measurements of soil moisture at meteorological stations in an Alpine catchment near Davos, Switzerland. It was found that the combination of a physical based snowpack model with a Richards equation solver seems to provide an adequate description of soil moisture fluctuations, especially in near surface layers. Soil moisture fluctuations, both measured and modelled, are strongly reduced when a snow cover is present. The measurements also revealed a strong increase in soil moisture, accompanied by a daily cycle in soil moisture during snow melt, extending down to 120cm depth. When soil properties from literature were assumed for the soil type in the vertical profile, the daily cycle in the model during snow melt was restricted mainly to the top layers, while observations show also a reaction in deeper layers. These observations are consistent with the assumption of the existence of preferential flow paths, which are not modelled by the Richards equation. This discrepancy between observations and model results during the melt phase may cause an underestimation of the soil storage capacity and an overestimation of the surface run-off in the model.

  18. Steel slags in a landfill top cover--experiences from a full-scale experiment.

    PubMed

    Andreas, L; Diener, S; Lagerkvist, A

    2014-03-01

    A full scale field study has been carried out in order to test and evaluate the use of slags from high-alloy steel production as the construction materials for a final cover of an old municipal landfill. Five test areas were built using different slag mixtures within the barrier layer (liner). The cover consisted of a foundation layer, a liner with a thickness of 0.7 m, a drainage layer of 0.3 m, a protection layer of 1.5 m and a vegetation layer of 0.25 m. The infiltration varied depending on the cover design used, mainly the liner recipe but also over time and was related to seasons and precipitation intensity. The test areas with liners composed of 50% electric arc furnace (EAF) slag and 50% cementitious ladle slag (LS) on a weight basis and with a proper consistence of the protection layer were found to meet the Swedish infiltration criteria of ⩽50 l (m(2)a)(-1) for final covers for landfills for non-hazardous waste: the cumulative infiltration rates to date were 44, 19 and 0.4 l (m(2)a)(-1) for A1, A4 and A5, respectively. Compared to the precipitation, the portion of leachate was always lower after the summer despite high precipitation from June to August. The main reason for this is evapotranspiration but also the fact that the time delay in the leachate formation following a precipitation event has a stronger effect during the shorter summer sampling periods than the long winter periods. Conventional techniques and equipment can be used but close cooperation between all involved partners is crucial in order to achieve the required performance of the cover. This includes planning, method and equipment testing and quality assurance. PMID:24393476

  19. A Water Balance Study of Four Landfill Cover Designs at Material Disposal Area B in Los Alamos, New Mexico

    SciTech Connect

    David D. Breshears; Fairley J. Barnes; John W. Nyhan; Johnny A. Salazar

    1998-09-01

    The goal of disposing of low-level radioactive and hazardous waste in shallow landfills is to reduce risk to human health and the environment by isolating contaminants until they no longer pose an unacceptable hazard. In order to achieve this, the Department of Energy Environmental Restoration Program is comparing the performance of several different surface covers at Material Disposal Area (MDA) B in Los Alamos. Two conventional landfill were compared with an improved cover designed to minimize plant and animal intrusion and to minimize water infiltration into the underlying wastes. The conventional covers varied in depth and both conventional and improved designs had different combinations of vegetation (grass verses shrub) and gravel mulch (no mulch verses mulch). These treatments were applied to each of 12 plots and water balance parameters were measured from March1987 through June 1995. Adding a gravel mulch significantly influenced the plant covered field plots receiving no gravel mulch averaged 21.2% shrub cover, while plots with gravel had a 20% larger percent cover of shrubs. However, the influence of gravel mulch on the grass cover was even larger than the influence on shrub cover, average grass cover on the plots with no gravel was 16.3%, compared with a 42% increase in grass cover due to gravel mulch. These cover relationships are important to reduce runoff on the landfill cover, as shown by a regression model that predicts that as ground cover is increased from 30 to 90%,annual runoff is reduced from 8.8 to 0.98 cm-a nine-fold increase. We also found that decreasing the slope of the landfill cover from 6 to 2% reduced runoff from the landfill cover by 2.7-fold. To minimize the risk of hazardous waste from landfills to humans, runoff and seepage need to be minimized and evapotranspiration maximized on the landfill cover. This has to be accomplished for dry and wet years at MDA B. Seepage consisted of 1.9% and 6.2% of the precipitation in the average and once in ten year events, respectively, whereas corresponding values for runoff were 13% and 16%; these changes were accompanied by corresponding decreases in evapotranspiration, which accounted for 86% and only 78% of the precipitation occurring on the average and once in ten year even~ respectively.

  20. Development of drainage water quality from a landfill cover built with secondary construction materials.

    PubMed

    Travar, Igor; Andreas, Lale; Kumpiene, Jurate; Lagerkvist, Anders

    2015-01-01

    The aim of this study was to evaluate the drainage water quality from a landfill cover built with secondary construction materials (SCM), fly ash (FA), bottom ash (BA) sewage sludge, compost and its changes over time. Column tests, physical simulation models and a full scale field test were conducted. While the laboratory tests showed a clear trend for all studied constituents towards reduced concentrations over time, the concentrations in the field fluctuated considerably. The primary contaminants in the drainage water were Cl(-), N, dissolved organic matter and Cd, Cu, Ni, Zn with initial concentrations one to three orders of magnitude above the discharge values to the local recipient. Using a sludge/FA mixture in the protection layer resulted in less contaminated drainage water compared to a sludge/BA mixture. If the leaching conditions in the landfill cover change from reduced to oxidized, the release of trace elements from ashes is expected to last about one decade longer while the release of N and organic matter from the sludge can be shortened with about two-three decades. The observed concentration levels and their expected development over time require drainage water treatment for at least three to four decades before the water can be discharged directly to the recipient. PMID:25305684

  1. Site Specific Landfill CH4 Emissions: Shortcomings of National GHG Inventory Guidelines and a New Process-Based Approach Linked to Climate and Soil Microclimate

    NASA Astrophysics Data System (ADS)

    Bogner, J. E.; Spokas, K.; Corcoran, M.

    2012-12-01

    Current (2006) IPCC national GHG inventory guidelines for landfill CH4, which estimate CH4 generation from the mass of waste in place, have high uncertainties, cannot be reliably related to measured emissions at specific sites, and lack comprehensive field validation. Moreover, measured landfill CH4 emissions vary over a wide range from >1000 g/m2/d down to negative values (uptake of atmospheric CH4). Literature over the last decade has emphasized that the major factors controlling emissions in these highly managed soil systems are gaseous transport rates as affected by the thickness and physical properties of cover soils, methanotrophic CH4 oxidation in cover materials as a function of seasonal soil microclimate. and the presence or absence of engineered gas extraction. Thus we developed and field validated a new site specific annual inventory model that incorporates specific soil profile properties and soil microclimate modeling coupled to 0.5° scale global climatic models. Based on 1D diffusion, CALMIM (California Landfill Methane Inventory Model) is a freely available JAVA tool which models a typical annual cycle for CH4 emissions from site specific daily, intermediate, and final landfill cover designs. This new approach, which is compliant with IPCC Tier III criteria, was originally field validated at two California sites (Monterey County; Los Angeles County), with limited field validation at three additional California sites. In addition to regional defaults for inventory purposes, CALMIM permits user selectable parameters and boundary conditions for more rigorous site specific applications where detailed CH4 emissions, meteorological, and soil microclimate data exist. We report here on improvements and expanded international field validation for CALMIM 5.2 in collaboration with research groups in the U.S., Europe, Africa, Asia, and Australia.odeled and measured annual cycle of landfill CH4 emissions for Austrian site. Cover consists of 50 cm sand & gravel overlain by 110 cm loam & sandy loam. No gas recovery. Site 100% vegetated.

  2. Isotopic tracing of landfill leachates and pollutant lead mobility in soil and groundwater.

    PubMed

    Vilomet, J D; Veron, A; Ambrosi, J P; Moustier, S; Bottero, J Y; Chatelet-Snidaro, L

    2003-10-15

    Here we provide evidence of the capability of stable lead isotopes to trace landfill leachate in a shallow groundwater. The municipal landfill we have investigated is located in southeastern France. It has no bottom liner, and wastes are placed directly on the ground. Stable lead isotopes allow the characterization of this landfill leachate signature (206Pb/207Pb = 1.189 +/- 0.004) that is clearly different from that of the local atmosphere (206Pb/207Pb = 1.150 +/- 0.006) and crustal lead (206Pb/207Pb = 1.200 +/- 0.005). Piezometers located in the direct vicinity of the landfill generally display this contaminant imprint. The landfill plume is monitored up to 1000 m downgradient of the landfill, in very good agreement with evaluation from chloride concentration. Meanwhile, 206Pb/207Pb ratios measured at a piezometer located 4600 m downgradient of the landfill suggest a contamination by the landfill plume. This result shows that the complexity of a pollutant plume dispersion in this shallow groundwater system requires several independent tracers to clearly resolve origin and transport pathways for contaminants. Furthermore, seasonal rainfall variation for this Mediterranean mixed Quaternary alluvion reservoir and the use of KCl fertilizers might favor an efficient remobilization of atmospheric lead in plowed soils and its transfer into groundwater as shown by lead isotope systematics. PMID:14594365

  3. LEACHATE CLOGGING ASSESSMENT OF GEOTEXTILE AND SOIL LANDFILL FILTERS

    EPA Science Inventory

    The liquids management strategy for any municipal or hazardous waste landfill requires a knowledgeable design strategy for the leachate collection system located at the base of the waste mass. Such leachate collection systems generally consist of sumps, perforated pipes, drainag...

  4. Soil contamination by heavy metals in landfills: measurements from an unlined leachate storage basin.

    PubMed

    Bouzayani, Fethi; Aydi, Abdelwaheb; Abichou, Tarek

    2014-08-01

    Landfills are sources of groundwater and soil pollution due to the production of leachate and its migration through refuse. This study was conducted in order to determine the extent of soil pollution within and around the Jebel Chakir landfill, located in the Tunis City, Tunisia. The main objective was to characterize soil samples of an unlined storage basin in relation to heavy metal concentrations in the Jebel Chakir landfill to the southwest of Tunis, Northern Tunisia. Twenty-four soil samples taken from different locations around the storage basin were analyzed by atomic absorption spectrophotometry for Cr, Cu, Ni, Pb, and Zn investigation. Our results indicated high concentrations of Cr (54.4-129.9mg/kg of DM), Zn (4.1-81.8mg/kg of DM), Ni (15.1-43.9mg/kg of DM), Pb (5.6-16.1mg/kg of DM), and Cu (0.2-1.84mg/kg of DM). These results suggested that contaminant migration is controlled by an active clay layer acting as an insulating material in the landfill. It is therefore necessary to set a treatment system for the landfill leachates and place a liner under the storage basin to reduce the pollution threat. PMID:24723123

  5. Assessment of Heavy Metals from Landfill Leachate Contaminated to Soil: A Case Study of Kham Bon Landfill, Khon Kaen Province, NE Thailand

    NASA Astrophysics Data System (ADS)

    Chuangcham, Udomporn; Wirojanagud, Wanpen; Charusiri, Punya; Milne-Home, William; Lertsirivorakul, Rungruang

    The distribution of heavy metals in landfill leachate contaminated to soil was investigated. Soil samples were collected at different times of the year as well as at various locations and depths in and around the landfill and throughout the contaminated area. The physical and chemical properties of the samples were analyzed. The results indicated that the heavy metals, namely Cd, Cr, Pb, Cu and Zn were significant concentrations in the soil within a radius of 2,000 m from the landfill. The Spearman`s rank correlation coefficient indicated that the appearance of high Cation exchange capacity, clay content and organic matter are statistically correlated with the high heavy metals accumulation. Moreover, the Fe and Mn oxide/oxyhydroxides plays important role in controlling heavy metals sink in soil as pointed out by the spearman ‘s rank correlation coefficient which corresponding to the soil type, red loess with high iron oxide, in the study area.

  6. A process-based inventory model for landfill CH4 emissions inclusive of seasonal soil microclimate and CH4 oxidation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have developed and field-validated an annual inventory model for California landfill CH4 emissions that incorporates both site-specific soil properties and soil microclimate modeling coupled to 0.5o scale global climatic models. Based on 1-D diffusion, CALMIM (California Landfill Methane Inventor...

  7. LEACHATE CLOGGING ASSESSMENT OF GEOTEXTILE AND SOIL LANDFILL FILTERS

    EPA Science Inventory

    This project was focused on the performance, design, testing and selection of filters used for leachate collection drains at the base of landfills, waste piles and other solid waste facilities. Geotextiles due to their manufactured uniformity, ease-of placement and savings in lan...

  8. The use of cover crops to manage soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cover crops are used to manage soils for many different reasons. Inserting cover crops into fallow periods and spaces in cropping systems is a beneficial soil management practice. Natural ecosystems typically have some plants growing, covering the soil, transpiring water, taking up nutrients, fixing...

  9. Contamination valuation of soil and groundwater source at anaerobic municipal solid waste landfill site.

    PubMed

    Aziz, Shuokr Qarani; Maulood, Yousif Ismael

    2015-12-01

    The present work aimed to determine the risks that formed landfill leachate from anaerobic Erbil Landfill Site (ELS) poses on groundwater source and to observe the effects of disposed municipal solid waste (MSW) on soil properties. The study further aims to fill the gap in studies on the effects of disposed MSW and produced leachate on the groundwater characteristics and soil quality at ELS, Iraq. Soil, leachate, and groundwater samples were collected from ELS for use as samples in this study. Unpolluted groundwater samples were collected from an area outside of the landfill. Field and laboratory experiments for the soil samples were conducted. Chemical analyses for the soil samples such as organic matter, total salts, and SO4 (=) were also performed. Raw leachate and groundwater samples were analyzed using physical and chemical experiments. The yields for sorptivity, steady-state infiltration rate, and hydraulic conductivity of the soil samples were 0.0006 m/?s, 0.00004 m/s, and 2.17 10(-5) m/s, respectively. The soil at ELS was found to be light brown clayey gravel with sand and light brown gravely lean clay layers with low permeability. Unprocessed leachate analysis identified the leachate as stabilized. Findings showed that the soil and groundwater at the anaerobic ELS were contaminated. PMID:26577215

  10. Study of Soil Washing for Remediation of Pb and Zn Contaminated Coastal Landfill

    NASA Astrophysics Data System (ADS)

    Park, S.; Kim, S.; Lee, M.

    2013-12-01

    As a result of analyzing the pre-treatment process of Pb, Zn in contaminated coastal landfill soil presented by Korean Soil Analysis Method, the each concentration was presented 577.00mg/kg, 3894.34mg/kg. This soil was critically contaminated with Pb and Zn because it was exceeded the Standard of soil contamination(2area: Pb-400mg/kg, Zn-600mg/kg). Soil remediation efficiency of the soil washing process for the removal of Pb and Zn was determined to be consistent with the results. The batch experiment on the several washing solutions(HCl, HNO3), washing solutions concentrations(0.1-0.8M) and the ratio of soil vs. solution for soil washing(1:3, 1:5 and 1:10) was performed. The results of experiments, washing time was appropriate in 30 minutes. The removal efficiency of soil washing increased as the ratio of soil vs. washing solution increased. But, in the case of heavy metals, the soil vs. solution for soil washing was determined as the optimal ratio of 1 : 5. Five consecutive soil washing with 0.5M of HCl and HNO3 solutions were performed. Results of experiments, in case of Pb was removed by target removal efficiency from soil on the twice washing. With in case of Zn was over on the first washing by target removal efficiency, but suggesting that twice consecutive soil washing is desirable as stability at field. Results of consecutive soil washing experiments, the removal efficiency maintained lower than 10 % after the 4th washing. From the results, demanding consecutive washing is not recommended. Results about the heavy metal contaminated soil washing experiments of the coastal landfill, in the case of HCl with more than 0.5 M of solution was performed at 1:5 of soil ratio vs. solution, 30 minutes of washing time and 2-3 consecutive soil washing. And in the case of HNO3 with 0.8 M of solution was performed various ratios of soil vs. washing solution, suggesting that 2-3 consecutive soil washing was reached to Pb and Zn target removal efficiency. Key words : landfill soil; washing solution; heavy metal contamination; soil remediation; soil washing; soil contamination

  11. Treatment of landfill leachate by using lateritic soil as a natural coagulant.

    PubMed

    Syafalni; Lim, Han Khim; Ismail, Norli; Abustan, Ismail; Murshed, Mohamad Fared; Ahmad, Anees

    2012-12-15

    In this research, the capability of lateritic soil used as coagulant for the treatment of stabilized leachate from the Penang-Malaysia Landfill Site was investigated. The evaluation of lateritic soil coagulant in comparison with commercialized chemical coagulants, such as alum, was performed using conventional jar test experiments. The optimum pH and coagulant dosage were identified for the lateritic soil coagulant and the comparative alum coagulant. It was found that the application of lateritic soil coagulant was quite efficient in the removal of COD, color and ammoniacal-nitrogen content from the landfill leachate. The optimal pH value was 2.0, while 14 g/L of lateritic soil coagulant was sufficient in removing 65.7% COD, 81.8% color and 41.2% ammoniacal-nitrogen. Conversely, the optimal pH and coagulant dosage for the alum were pH 4.8 and 10 g/L respectively, where 85.4% COD, 96.4% color and 47.6% ammoniacal-nitrogen were removed from the same leachate sample. Additionally, the Sludge Volume Index (SVI) ratio of alum and lateritic soil coagulant was 53:1, which indicated that less sludge was produced and was an environmentally friendly product. Therefore, lateritic soil coagulant can be considered a viable alternative in the treatment of landfill leachate. PMID:22964042

  12. Barometric pumping of burial trench soil gases into the atmosphere at the 740-G Sanitary Landfill

    SciTech Connect

    Wyatt, D.E.; Pirkle, R.J.; Masdea, D.J.

    1992-12-01

    In 1991, a soil gas survey was performed at the Savannah River Site Sanitary Landfill as part of the characterization efforts required under the integrated Resource Conservation and Recovery Act (RCRA) Facility Investigation and Comprehensive Environmental Resource Conservation and Recovery Act (CERCLA) Remedial Investigation (RFI/RI) program. This report details the findings of this survey, which identified several areas of the landfill that were releasing volatile organic compounds to the atmosphere at levels exceeding regulatory standards. Knowledge of the rates of VOC outgassing is necessary to protect site workers, provide input into the human health and environmental risk assessment documents and provide input into the remedial design scenario.

  13. Characterization of trichloroethylene adsorption onto waste biocover soil in the presence of landfill gas.

    PubMed

    He, Ruo; Su, Yao; Kong, Jiaoyan

    2015-09-15

    Waste biocover soils (WBS) have been demonstrated to have great potential in mitigating trichloroethylene (TCE) emission from landfills, due to the relatively high TCE-degrading capacity. In this study, the characteristics of TCE adsorption on WBS in the presence of the major landfill gas components (i.e., CH4 and CO2) were investigated in soil microcosms. The adsorption isotherm of TCE onto WBS was fitted well with linear model within the TCE concentrations of 7000 ppmv. The adsorption capacity of TCE onto WBS was affected by temperature, soil moisture content and particle size, of which, temperature was the dominant factor. The adsorption capacity of TCE onto the experimental materials increased with the increasing organic matter content. A significantly positive correlation was observed between the adsorption capacity of TCE and the organic matter content of experimental materials that had relatively higher organic content (r = 0.988, P = 0.044). To better understand WBS application in practice, response surface methodology was developed to predict TCE adsorption capacity and emissions through WBS in different landfills in China. These results indicated that WBS had high adsorption capacity of TCE in LFG and temperature should be paid more attention to manipulate WBS to reduce TCE emissions from landfills. PMID:25909498

  14. Estimation on the self recovery behavior of low-conductivity layer in landfill final cover by laboratory conductivity tests.

    PubMed

    Kwon, O; Park, J

    2006-11-01

    This study examined the application of a Self Recovering Sustainable Layer (SRSL) as a landfill final cover. Low-conductivity layers in landfill covers are known to have problems associated with cracking as a result of the differential settlement or climatic changes. A SRSL is defined as a layer with chemical properties that reduces the increased hydraulic conductivity resulting from cracking by forming low-conductivity precipitates of chemicals contained in the layer. In this study, the formation of precipitates was confirmed using a batch test, spectroscopic analysis and mineralogical speciation tests. The possibility of secondary contamination due to the chemicals used for recovery was evaluated using a leaching test. A laboratory conductivity test was performed on a single layer composed of each chemical as well as on a 2-layer system. The recovery performance of the SRSL was estimated by developing artificial cracks in the specimens and observing the change in hydraulic conductivity as a function of time. In the laboratory conductivity test, the hydraulic conductivity of a 2-layer system as well as those of the individual layers that comprise the 2-layer system was estimated. In addition sodium ash was found to enhance the reduction in conductivity. A significant increase in conductivity was observed after the cracks developed but this was reduced with time, which indicated that the SRSL has a proper recovering performance. In conclusion, a SRSL can be used as a landfill final cover that could maintain low-conductivity even after the serious damages due to settlement. PMID:17203605

  15. Effect of Cover Crops on Soil Fungal Diversity and Biomass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The effects of various cover crops (sordan, mustard, canola, honeysweet, and fallow) to influence soil fungal biomass and diversity were tested in a potato field in the San Luis Valley, Colorado. Soil samples (0-5 cm depth) were randomly selected from each cover crop plot and soil fungal communitie...

  16. THE USE OF ALTERNATIVE MATERIALS FOR DAILY COVER AT MUNICIPAL SOLID WASTE LANDFILLS. A Project Summary (EPA/600/SR-93/172)

    EPA Science Inventory

    This investigation was conducted to assess the applicability of currently available (ca. 1992) alternative materials for use as daily cover at landfills. Information on characteristics, material and equipment requirements, methods of preparation and application, climatic and ope...

  17. Potential use of lateritic and marine clay soils as landfill liners to retain heavy metals.

    PubMed

    Chalermyanont, Tanit; Arrykul, Surapon; Charoenthaisong, Nanthanit

    2009-01-01

    The potential of a lateritic soil and a marine clay, typical of those found in hot and humid climatic regions, was assessed for use as a landfill liner material. A series of tests were conducted - physical and chemical, batch adsorption, column, hydraulic conductivity, etc., - to evaluate the heavy metal sorption capacity, chemical compatibility of hydraulic conductivity, and transport parameters of the soils. Experimental results showed that the marine clay had better adsorption capacity than that of the lateritic soil and that its hydraulic conductivity was an order of magnitude lower. In addition, the hydraulic conductivities of both soils when permeated with low concentration heavy metal solutions were below 1x10(-7)cm/s. When permeated with Cr, Pb, Cd, Zn, and Ni solutions, the retardation factors of the lateritic soil and the marine clay ranged from 10 to 98 and 37 to 165, respectively, while the diffusion coefficients ranged from 1.0x10(-5) to 7.5x10(-6) and 3.0 to 9.14x10(-7)cm2/s, respectively. For both soils, Cr and Pb were retained relatively well, while Cd, Zn, and Ni were more mobile. The marine clay had higher retardation factors and lower diffusion coefficients, and its hydraulic conductivity was more compatible with Cr solution, than that of the lateritic soil. In general, the properties of the marine clay indicate that it has significant advantages over the lateritic soil as landfill liner material. PMID:18550353

  18. Effects of ammonium on the activity and community of methanotrophs in landfill biocover soils.

    PubMed

    Zhang, Xuan; Kong, Jiao-Yan; Xia, Fang-Fang; Su, Yao; He, Ruo

    2014-06-01

    The influence of NH4(+) on microbial CH4 oxidation is still poorly understood in landfill cover soils. In this study, effects of NH4(+) addition on the activity and community structure of methanotrophs were investigated in waste biocover soil (WBS) treated by a series of NH4(+)-N contents (0, 100, 300, 600 and 1200mgkg(-1)). The results showed that the addition of NH4(+)-N ranging from 100 to 300mgkg(-1) could stimulate CH4 oxidation in the WBS samples at the first stage of activity, while the addition of an NH4(+)-N content of 600mgkg(-1) had an inhibitory effect on CH4 oxidation in the first 4 days. The decrease of CH4 oxidation rate observed in the last stage of activity could be caused by nitrogen limitation and/or exopolymeric substance accumulation. Type I methanotrophs Methylocaldum and Methylobacter, and type II methanotrophs (Methylocystis and Methylosinus) were abundant in the WBS samples. Of these, Methylocaldum was the main methanotroph in the original WBS. With incubation, a higher abundance of Methylobacter was observed in the treatments with NH4(+)-N contents greater than 300mgkg(-1), which suggested that NH4(+)-N addition might lead to the dominance of Methylobacter in the WBS samples. Compared to type I methanotrophs, the abundance of type II methanotrophs Methylocystis and/or Methylosinus was lower in the original WBS sample. An increase in the abundance of Methylocystis and/or Methylosinus occurred in the last stage of activity, and was likely due to a nitrogen limitation condition. Redundancy analysis showed that NH4(+)-N and the C/N ratio had a significant influence on the methanotrophic community in the WBS sample. PMID:24794017

  19. About soil cover heterogeneity of agricultural research stations' experimental fields

    NASA Astrophysics Data System (ADS)

    Rannik, Kaire; Kõlli, Raimo; Kukk, Liia

    2013-04-01

    Depending on local pedo-ecological conditions (topography, (geo) diversity of soil parent material, meteorological conditions) the patterns of soil cover and plant cover determined by soils are very diverse. Formed in the course of soil-plant mutual relationship, the natural ecosystems are always influenced to certain extent by the other local soil forming conditions or they are site specific. The agricultural land use or the formation of agro-ecosystems depends foremost on the suitability of soils for the cultivation of feed and food crops. As a rule, the most fertile or the best soils of the area, which do not present any or present as little as possible constraints for agricultural land use, are selected for this purpose. Compared with conventional field soils, the requirements for the experimental fields' soil cover quality are much higher. Experimental area soils and soil cover composition should correspond to local pedo-ecological conditions and, in addition to that, represent the soil types dominating in the region, whereas the fields should be as homogeneous as possible. The soil cover heterogeneity of seven arable land blocks of three research stations (Jõgeva, Kuusiku and Olustvere) was studied 1) by examining the large scale (1:10 000) digital soil map (available via the internet), and 2) by field researches using the transect method. The stages of soils litho-genetic and moisture heterogeneities were estimated by using the Estonian normal soils matrix, however, the heterogeneity of top- and subsoil texture by using the soil texture matrix. The quality and variability of experimental fields' soils humus status, was studied more thoroughly from the aspect of humus concentration (g kg-1), humus cover thickness (cm) and humus stocks (Mg ha-1). The soil cover of Jõgeva experimental area, which presents an accumulative drumlin landscape (formed during the last glacial period), consist from loamy Luvisols and associated to this Cambisols. In Kuusiku area, which landscape is characterized by till and limestone plains with thin Quaternary cover, the soil cover is more heterogeneous than in previous area. Kuusiku soil cover is more variegated by the soil texture and as well as by the genesis of soils. In addition to Cambisols, Leptosols, Gleysols and Luvisols may be found here as well. The dominating soils in Olustvere research area, which is situated on wavy upland plateau, are Albeluvisols.

  20. Differential Soil Acidity Tolerance of Tropical Legume Cover Crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In tropical regions, soil acidity and low soil fertility are the most important yield limiting factors for sustainable crop production. Using legume cover crops as mulch is an important strategy not only to protect the soil loss from erosion but also ameliorating soil fertility. Information is limit...

  1. Relationship between hydraulic properties and plant coverage of the closed-landfill soils in Piacenza (Po Valley, Italy)

    NASA Astrophysics Data System (ADS)

    Cassinari, C.; Manfredi, P.; Giupponi, L.; Trevisan, M.; Piccini, C.

    2015-07-01

    In this paper the results of a study of soil hydraulic properties and plant coverage of a landfill located in Piacenza (Po Valley, Italy) are presented, together with the attempt to relate the hydraulic properties in relation with plant coverage. The measured soil water retention curve was first compared with the output of pedotransfer functions taken from the literature and then compared with the output of the same pedotransfer functions applied to a reference soil. The landfill plant coverage was also studied. The relationship between soil hydraulic properties and plant coverage showed that the landfill soils have a low water content available for plants. The soils' low water content, together with a lack of depth and a compacted structure, justifies the presence of a nitrophilous, disturbed-soil vegetation type, dominated by ephemeral annual species (therophytes).

  2. INVESTIGATION OF LANDFILL LEACHATE POLLUTANT ATTENUATION BY SOILS

    EPA Science Inventory

    In this laboratory study using 11 soils from 7 major orders in the U.S., the movement and retention of As, Be, Cd, CN, Cr, Cu, Hg, Ni, Pb, Se, V, and Zn when carried by municipal solid waste (MSW) leachate through soils was influenced by the individual properties of the elements,...

  3. Methane emissions from MBT landfills

    SciTech Connect

    Heyer, K.-U. Hupe, K.; Stegmann, R.

    2013-09-15

    Highlights: • Compilation of methane generation potential of mechanical biological treated (MBT) municipal solid waste. • Impacts and kinetics of landfill gas production of MBT landfills, approach with differentiated half-lives. • Methane oxidation in the waste itself and in soil covers. • Estimation of methane emissions from MBT landfills in Germany. - Abstract: Within the scope of an investigation for the German Federal Environment Agency (“Umweltbundesamt”), the basics for the estimation of the methane emissions from the landfilling of mechanically and biologically treated waste (MBT) were developed. For this purpose, topical research including monitoring results regarding the gas balance at MBT landfills was evaluated. For waste treated to the required German standards, a methane formation potential of approximately 18–24 m{sup 3} CH{sub 4}/t of total dry solids may be expected. Monitoring results from MBT landfills show that a three-phase model with differentiated half-lives describes the degradation kinetics in the best way. This is due to the fact that during the first years of disposal, the anaerobic degradation processes still proceed relatively intensively. In addition in the long term (decades), a residual gas production at a low level is still to be expected. Most of the soils used in recultivation layer systems at German landfills show a relatively high methane oxidation capacity up to 5 l CH{sub 4}/(m{sup 2} h). However, measurements at MBT disposal sites indicate that the majority of the landfill gas (in particular at non-covered areas), leaves the landfill body via preferred gas emission zones (hot spots) without significant methane oxidation. Therefore, rather low methane oxidation factors are recommended for open and temporarily covered MBT landfills. Higher methane oxidation rates can be achieved when the soil/recultivation layer is adequately designed and operated. Based on the elaborated default values, the First Order Decay (FOD) model of the IPCC Guidelines for National Greenhouse Gas Inventories, 2006, was used to estimate the methane emissions from MBT landfills. Due to the calculation made by the authors emissions in the range of 60,000–135,000 t CO{sub 2-eq.}/a for all German MBT landfills can be expected. This wide range shows the uncertainties when the here used procedure and the limited available data are applied. It is therefore necessary to generate more data in the future in order to calculate more precise methane emission rates from MBT landfills. This is important for the overall calculation of the climate gas production in Germany which is required once a year by the German Government.

  4. Relation between hydraulic properties and plant coverage of the closed-landfill soils in Piacenza (Po Valley, Italy)

    NASA Astrophysics Data System (ADS)

    Cassinari, C.; Manfredi, P.; Giupponi, L.; Trevisan, M.; Piccini, C.

    2015-02-01

    In this paper the results of a study of soil hydraulic properties and plant coverage of a landfill located in Piacenza (Po Valley, Italy) are presented, together with the attempt to put the hydraulic properties in relation with plant coverage. The measured soil water retention curve was first compared with the output of some pedotransfer functions taken from the literature and then with the output of the same pedotransfer functions applied to a reference soil. The landfill plant coverage was also studied. The relation between soil hydraulic properties and plant coverage showed that the landfill soils have a low water content available for plants and this fact, together with their lack of depth and compacted structure, justifies the presence of a nitrophilous, disturbed-soil vegetation type, dominated by ephemeral annual species (therophytes).

  5. Soil cover of gas-bearing areas

    NASA Astrophysics Data System (ADS)

    Mozharova, N. V.

    2010-08-01

    Natural soils with disturbed functioning parameters compared to the background soils with conservative technogenic-pedogenic features were distinguished on vast areas above the artificial underground gas storages in the zones of spreading and predominant impact of hydrocarbon gases. The disturbance of the functioning parameters is related to the increase in the methane concentration, the bacterial oxidation intensity and destruction, and the complex microbiological and physicochemical synthesis of iron oxides. The technogenic-pedogenic features include neoformations of bacteriomorphic microdispersed iron oxides. The impurity components consist of elements typical for biogenic structures. New soil layers, horizons, specific anthropogenically modified soils, and soil-like structures were formed on small areas in the industrial zones of underground gas storages due to the mechanical disturbance, the deposition of drilling sludge, and the chemical contamination. Among the soils, postlithogenic formations were identifiedchemotechnosols (soddy-podzolic soils and chernozems), as well as synlithogenic ones: strato-chemotechnosols and stratochemoembryozems. The soil-like bodies included postlithogenic soil-like structures (chemotechnozems) and synlithogenic ones (strato-chemotechnozems). A substantive approach was used for the soil diagnostics. The morphological and magnetic profiles and the physical, chemical, and physicochemical properties of the soils were analyzed. The micromorphological composition of the soil magnetic fraction was used as a magnetic label.

  6. The release of As, Cr and Cu from contaminated soil stabilized with APC residues under landfill conditions.

    PubMed

    Travar, I; Kihl, A; Kumpiene, J

    2015-03-15

    The aim of this study was to investigate the stability of As, Cr and Cu in contaminated soil treated with air pollution control residues under landfill conditions. The influence of landfill gas and temperature on the release of trace elements from stabilized soil was simulated using a diffusion test. The air pollution control residues immobilized As through the precipitation of Ca-As minerals (calcium arsenate (Ca5H2(AsO4)3 5H2O), weilite (CaAsO4) and johnbaumite (Ca5(AsO4)3(OH)), incorporation of As into ettringite (Ca6Al2(SO4)3(OH)12 26H2O) and adsorption by calcite (CaCO3). The air pollution control residues generally showed a high resistance to pH reduction, indicating high buffer capacity and stability of immobilized As in a landfill over time. Generation of heat in a landfill might increase the release of trace elements. The release of As from stabilized soil was diffusion-controlled at 60 C, while surface wash-off, dissolution, and depletion prevailed at 20 C. The air pollution control residues from the incineration of municipal solid waste immobilized Cr, indicating its stability in a landfill. The treatment of soil with air pollution control residues was not effective in immobilization of Cu. Contaminated soils treated with air pollution control residues will probably have a low impact on overall leachate quality from a landfill. PMID:25528268

  7. Passive and active soil gas sampling at the Mixed Waste Landfill, Technical Area III, Sandia National Laboratories/New Mexico

    SciTech Connect

    McVey, M.D.; Goering, T.J.; Peace, J.L.

    1996-02-01

    The Environmental Restoration Project at Sandia National Laboratories, New Mexico is tasked with assessing and remediating the Mixed Waste Landfill in Technical Area III. The Mixed Waste Landfill is a 2.6 acre, inactive radioactive and mixed waste disposal site. In 1993 and 1994, an extensive passive and active soil gas sampling program was undertaken to identify and quantify volatile organic compounds in the subsurface at the landfill. Passive soil gas surveys identified levels of PCE, TCE, 1,1, 1-TCA, toluene, 1,1,2-trichlorotrifluoroethane, dichloroethyne, and acetone above background. Verification by active soil gas sampling confirmed concentrations of PCE, TCE, 1,1,1-TCA, and 1,1,2-trichloro-1,2,2-trifluoroethane at depths of 10 and 30 feet below ground surface. In addition, dichlorodifluoroethane and trichlorofluoromethane were detected during active soil gas sampling. All of the volatile organic compounds detected during the active soil gas survey were present in the low ppb range.

  8. Soil changes covered by grass and grazed by cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil properties change with time when exposed to perennial grass cover and subsequently grazed by cattle because of the large input of organic matter that typically occurs at the soil surface from senescent plant residues and animal manure. The accumulation of organic matter at the soil surface res...

  9. Design of landfill daily cells.

    PubMed

    Panagiotakopoulos, D; Dokas, I

    2001-08-01

    The objective of this paper is to study the behaviour of the landfill soil-to-refuse (S/R) ratio when size, geometry and operating parameters of the daily cell vary over realistic ranges. A simple procedure is presented (1) for calculating the cell parameters values which minimise the S/R ratio and (2) for studying the sensitivity of this minimum S/R ratio to variations in cell size, final refuse density, working face length, lift height and cover thickness. In countries where daily soil cover is required, savings in landfill space could be realised following this procedure. The sensitivity of minimum S/R to variations in cell dimensions decreases with cell size. Working face length and lift height affect the S/R ratio significantly. This procedure also offers the engineer an additional tool for comparing one large daily cell with two or more smaller ones, at two different working faces within the same landfill. PMID:11720268

  10. Evaluation of engineering properties for the use of leached brown coal ash in soil covers.

    PubMed

    Mudd, Gavin M; Chakrabarti, Srijib; Kodikara, Jayantha

    2007-01-31

    The need to engineer cover systems for the successful rehabilitation or remediation of a wide variety of solid wastes is increasing. Some common applications include landfills, hazardous waste repositories, or mine tailings dams and waste rock/overburden dumps. The brown coal industry of the Latrobe Valley region of Victoria, Australia, produces significant quantities of coal ash and overburden annually. There are some site-specific acid mine drainage (AMD) issues associated with overburden material. This needs to be addressed both during the operational phase of a project and during rehabilitation. An innovative approach was taken to investigate the potential to use leached brown coal ash in engineered soil covers on this overburden dump. The basis for this is two-fold: first, the ash has favourable physical characteristics for use in cover systems (such as high storage capacity/porosity, moderately low permeability, and an ability to act as a capillary break layer generating minimal leachate or seepage); and second, the leachate from the ash is mildly alkaline (which can help to mitigate and reduce the risk of AMD). This paper will review the engineering issues involved in using leached brown coal ash in designing soil covers for potentially acid-forming overburden dumps. It presents the results of laboratory work investigating the technical feasibility of using leached brown coal ash in engineered solid waste cover systems. PMID:16621267

  11. Characterization of landfill gas composition at the Fresh Kills municipal solid-waste landfill

    SciTech Connect

    Eklund, B.; Anderson, E.P.; Walker, B.L.; Burrows, D.B.

    1998-08-01

    The most common disposal method in the US for municipal solid waste (MSW) is burial in landfills. Until recently, air emissions from these landfills were not regulated. Under the New Source Performance Standards and Emission Guidelines for MSW landfills, MSW operators are required to determine the nonmethane organic gas generation rate of their landfill through modeling and/or measurements. This paper summarizes speciated nonmethane organic compound (NMOC) measurement data collected during an intensive, short-term field program. Over 250 separate landfill gas samples were collected from emission sources at the Fresh Kills landfill in New York City and analyzed for approximately 150 different analytes. The average total NMOC value for the landfill was 438 ppmv (as hexane) versus the regulatory default value of 4,000 ppmv (as hexane). Over 70 individual volatile organic compounds (VOCs) were detected and quantified in the landfill gas samples. The typical gas composition for this landfill was determined as well as estimates of the spatial, temporal, and measurement variability in the gas composition. The data for NMOC show that the gas composition within the landfill is equivalent to the composition of the gas exiting the landfill through passive vents and through the soil cover.

  12. Assessment of soil-gas, soil, and water contamination at the former hospital landfill, Fort Gordon, Georgia, 2009-2010

    USGS Publications Warehouse

    Falls, Fred W.; Caldwell, Andral W.; Guimaraes, Wladmir B.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

    2011-01-01

    Soil gas, soil, and water were assessed for organic and inorganic constituents at the former hospital landfill located in a 75-acre study area near the Dwight D. Eisenhower Army Medical Center, Fort Gordon, Georgia, from April to September 2010. Passive soil-gas samplers were analyzed to evaluate organic constituents in the hyporheic zone of a creek adjacent to the landfill and soil gas within the estimated boundaries of the former landfill. Soil and water samples were analyzed to evaluate inorganic constituents in soil samples, and organic and inorganic constituents in the surface water of a creek adjacent to the landfill, respectively. This assessment was conducted to provide environmental constituent data to Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. Results from the hyporheic-zone assessment in the unnamed tributary adjacent to the study area indicated that total petroleum hydrocarbons and octane were the most frequently detected organic compounds in groundwater beneath the creek bed. The highest concentrations for these compounds were detected in the upstream samplers of the hyporheic-zone study area. The effort to delineate landfill activity in the study area focused on the western 14 acres of the 75-acre study area where the hyporheic-zone study identified the highest concentrations of organic compounds. This also is the part of the study area where a debris field also was identified in the southern part of the 14 acres. The southern part of this 14-acre study area, including the debris field, is steeper and not as heavily wooded, compared to the central and northern parts. Fifty-two soil-gas samplers were used for the July 2010 soil-gas survey in the 14-acre study area and mostly detected total petroleum hydrocarbons, and gasoline and diesel compounds. The highest soil-gas masses for total petroleum hydrocarbons, diesel compounds, and the only valid detection of perchloroethene were in the southern part of the study area to the west of the debris field. However, all other detections of total petroleum hydrocarbons greater than 10 micrograms and diesel greater than 0.04 micrograms, and all detections of the combined mass of benzene, toluene, ethylbenzene, and xylene were found down slope from the debris field in the central and northern parts of the study area. Five soil-gas samplers were deployed and recovered from September 16 to 22, 2010, and were analyzed for organic compounds classified as chemical agents or explosives. Chloroacetophenones (a tear gas component) were the only compounds detected above a method detection level and were detected at the same location as the highest total petroleum hydrocarbons and diesel detections in the southern part of the 14-acre study area. Composite soil samples collected at five locations were analyzed for 35 inorganic constituents. None of the inorganic constituents exceeded the regional screening levels. One surface-water sample collected in the western end of the hyporheic-zone study area had a trichlorofluoromethane concentration above the laboratory reporting level and estimated concentrations of chloroform, fluoranthene, and isophorone below laboratory reporting levels.

  13. Monitoring the Performance of an Alternative Landfill Cover at the Monticello, Utah, Uranium Mill Tailings Disposal Site

    SciTech Connect

    Waugh, W.J.; Kastens, M.K.; Sheader, L.R.L.; Benson, C.H.; Albright, W.H.; Mushovic, P.S.

    2008-07-01

    The U.S. Department of Energy Office of Legacy Management (DOE) and the U.S. Environmental Protection Agency (EPA) collaborated on the design and monitoring of an alternative cover for the Monticello uranium mill tailings disposal cell, a Superfund site in southeastern Utah. Ground-water recharge is naturally limited at sites like Monticello where thick, fine-textured soils store precipitation until evaporation and plant transpiration seasonally return it to the atmosphere. The cover at Monticello uses local soils and a native plant community to mimic the natural soil water balance. The cover is fundamentally an evapotranspiration (ET) design with a capillary barrier. A 3-hectare drainage lysimeter was embedded in the cover during construction of the disposal cell in 2000. The lysimeter consists of a geo-membrane liner below the capillary barrier that directs percolation water to a monitoring system. Soil water storage is determined by integration of point water content measurements. Meteorological parameters are measured nearby. Plant cover, shrub density, and leaf area index (LAI) are monitored annually. The cover performed well over the 7-year monitoring period (2000-2007). The cumulative percolation was 4.2 mm (0.6 mm yr{sup -1}), satisfying an EPA goal of an average percolation of <3.0 mm yr{sup -1}. Almost all percolation can be attributed to the exceptionally wet winter and spring of 2004-2005 when soil water content slightly exceeded the water storage capacity of the cover. The diversity, percent cover, and LAI of vegetation increased over the monitoring period, although the density of native shrubs that extract water from deeper in the cover has remained less than revegetation targets. DOE and EPA are applying the monitoring results to plan for long-term surveillance and maintenance and to evaluate alternative cover designs for other waste disposal sites. (authors)

  14. Landfill bioreactor design and operation

    SciTech Connect

    Reinhart, D.R.; Townsend, T.

    1998-12-31

    Landfill Bioreactor Design and Operation covers the history and background of landfill technology, research studies of actual bioreactor landfills, expected leachate and gas yields, specific design criteria, operation guidelines, and reuse of landfill sites to avoid having to establish new sites. For anyone looking for an alternative to large, wasteful landfill sites, this book provides a practical alternative to the problem.

  15. Soil cover by natural trees in agroforestry systems

    NASA Astrophysics Data System (ADS)

    Diaz-Ambrona, C. G. H.; Almoguera Millán, C.; Tarquis Alfonso, A.

    2009-04-01

    The dehesa is common agroforestry system in the Iberian Peninsula. These open oak parklands with silvo-pastoral use cover about two million hectares. Traditionally annual pastures have been grazed by cows, sheep and also goats while acorns feed Iberian pig diet. Evergreen oak (Quercus ilex L.) has other uses as fuelwood collection and folder after tree pruning. The hypothesis of this work is that tree density and canopy depend on soil types. We using the spanish GIS called SIGPAC to download the images of dehesa in areas with different soil types. True colour images were restoring to a binary code, previously canopy colour range was selected. Soil cover by tree canopy was calculated and number of trees. Processing result was comparable to real data. With these data we have applied a dynamic simulation model Dehesa to determine evergreen oak acorn and annual pasture production. The model Dehesa is divided into five submodels: Climate, Soil, Evergreen oak, Pasture and Grazing. The first three require the inputs: (i) daily weather data (maximum and minimum temperatures, precipitation and solar radiation); (ii) the soil input parameters for three horizons (thickness, field capacity, permanent wilting point, and bulk density); and (iii) the tree characterization of the dehesa (tree density, canopy diameter and height, and diameter of the trunk). The influence of tree on pasture potential production is inversely proportional to the canopy cover. Acorn production increase with tree canopy cover until stabilizing itself, and will decrease if density becomes too high (more than 80% soil tree cover) at that point there is competition between the trees. Main driving force for dehesa productivity is soil type for pasture, and tree cover for acorn production. Highest pasture productivity was obtained on soil Dystric Planosol (Alfisol), Dystric Cambisol and Chromo-calcic-luvisol, these soils only cover 22.4% of southwest of the Iberian peninssula. Lowest productivity was obtained on Dystric Lithosol.

  16. Comparison of soil moisture dynamics across different land covers

    NASA Astrophysics Data System (ADS)

    Mittelbach, Heidi; Henschel, Florian; Seneviratne, Sonia I.

    2013-04-01

    The spatial and temporal variability of soil moisture and its dependency on local or regional scale characteristics, such as soil texture, land cover and topography as well as weather and climate anomalies, is a fundamental feature for environmental applications. In a recent study based on a network of grassland stations in Switzerland (Mittelbach and Seneviratne 2012), it was shown that the spatio-temporal variability of absolute soil moisture is clearly distinct from the spatio-temporal variability of temporal soil moisture anomalies, and that regional-scale patterns of soil moisture dynamics could clearly be identified at the scale of Switzerland. However, it has not yet been investigated whether these conclusions apply across land cover types. In the current study, we investigate differences in soil moisture dynamics at paired grassland-forest sites and their dependency either on dynamic or static site properties. The analysis is based on three-year continuous soil moisture measurements at three paired grassland and nearby forest sites of the SwissSMEX (http://www.iac.ethz.ch/url/research/SwissSMEX) soil moisture network. The three paired sites are located in different climatic regions of Switzerland. They are characterized by similar meteorological conditions but within the pairs differences in topography (elevation, slope, aspect) and soil properties are found. At all sites continuous measurements of soil moisture are available in four different depths, from 5 cm to 50 cm. The analyses of daily mean soil moisture at the single depths and integrated over the 50 cm soil column reveal different behaviour with respect to absolute soil moisture levels and temporal soil moisture dynamics between grassland and forest sites during the whole three-year period. Focusing on the recession of soil moisture during precipitation-free periods, a seasonal dependency is observed with strongest recession in summer for both land covers. However, a different behaviour is found in spring and autumn. While stronger recession is found over grassland in spring, the forest sites indicate stronger recession in autumn, with most pronounced differences at deeper depths. This investigation thus suggests that differences in soil moisture dynamics across land cover types depend on the dynamics of the vegetation cover and less on static site properties. Reference: Mittelbach, H., and S.I. Seneviratne, 2012: A new perspective on the spatio-temporal variability of soil moisture: temporal dynamics versus time invariant contributions. Hydrol. Earth Syst. Sci., 16, 2169-2179.

  17. Controlling landfill closure costs

    SciTech Connect

    Millspaugh, M.P.; Ammerman, T.A.

    1995-05-01

    Landfill closure projects are significant undertakings typically costing well over $100,000/acre. Innovative designs, use of alternative grading and cover materials, and strong project management will substantially reduce the financial impact of a landfill closure project. This paper examines and evaluates the various elements of landfill closure projects and presents various measures which can be employed to reduce costs. Control measures evaluated include: the beneficial utilization of alternative materials such as coal ash, cement kiln dust, paper mill by-product, construction surplus soils, construction debris, and waste water treatment sludge; the appropriate application of Mandate Relief Variances to municipal landfill closures for reduced cover system requirements and reduced long-term post closure monitoring requirements; equivalent design opportunities; procurement of consulting and contractor services to maximize project value; long-term monitoring strategies; and grant loan programs. An analysis of closure costs under differing assumed closure designs based upon recently obtained bid data in New York State, is also provided as a means for presenting the potential savings which can be realized.

  18. Assessment of soil-gas and groundwater contamination at the Gibson Road landfill, Fort Gordon, Georgia, 2011

    USGS Publications Warehouse

    Falls, W. Fred; Caldwell, Andral W.; Guimaraes, Wladmir G.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

    2012-01-01

    Soil-gas and groundwater assessments were conducted at the Gibson Road landfill in 201 to provide screening-level environmental contamination data to supplement the data collected during previous environmental studies at the landfill. Passive samplers were used in both assessments to detect volatile and semivolatile organic compounds and polycyclic aromatic hydrocarbons in soil gas and groundwater. A total of 56 passive samplers were deployed in the soil in late July and early August for the soil-gas assessment. Total petroleum hydrocarbons (TPH) were detected at masses greater than the method detection level of 0.02 microgram in all samplers and masses greater than 2.0 micrograms in 13 samplers. Three samplers located between the landfill and a nearby wetland had TPH masses greater than 20 micrograms. Diesel was detected in 28 of the 56 soil-gas samplers. Undecane, tridecane, and pentadecane were detected, but undecane was the most common diesel compound with 23 detections. Only five detections exceeded a combined diesel mass of 0.10 microgram, including the highest mass of 0.27 microgram near the wetland. Toluene was detected in only five passive samplers, including masses of 0.65 microgram near the wetland and 0.85 microgram on the southwestern side of the landfill. The only other gasoline-related compound detected was octane in two samplers. Naphthalene was detected in two samplers in the gully near the landfill and two samplers along the southwestern side of the landfill, but had masses less than or equal to 0.02 microgram. Six samplers located southeast of the landfill had detections of chlorinated compounds, including one perchloroethene detections (0.04 microgram) and five chloroform detections (0.05 to0.08 microgram). Passive samplers were deployed and recovered on August 8, 2011, in nine monitoring wells along the southwestern, southeastern and northeastern sides of the landfill and down gradient from the eastern corner of the landfill. Six of the nine samplers had TPH concentrations greater than 100 micrograms per liter. TPH concentrations declined from 320 micrograms per liter in a sampler near the landfill to 18 micrograms in a sampler near the wetland. Five of the samplers had detections of one or more diesel compounds but detections of individual diesel compounds had concentrations below a method detection level of 0.01 microgram per liter. Benzene was detected in three samplers and exceeded the national primary drinking-water standard of 5 micrograms per liter set by the U.S. Environmental Protection Agency. The concentrations of benzene, and therefore BTEX, were 6.1 micrograms per liter in the sampler near the eastern corner of the landfill, 27 micrograms per liter in the sampler near the wetland, and 37 micrograms per liter in the sampler at the southern corner of the landfill. Nonfuel-related compounds were detected in the four wells that are aligned between the eastern corner of the landfill and the wetland. The sampler deployed nearest the eastern corner of the landfill had the greatest number of detected organic compounds and had the only detections of two trimethylbenzene compounds, naphthalene, 2-methyl naphthalene, and 1,4-dichlorobenzene. The two up gradient samplers had the greatest number of chlorinated compounds with five compounds each, compared to detections of four compounds and one compound in the two down gradient samplers. All four samplers had detections of 1,1-dichloroethane which ranged from 42 to 1,300 micrograms per liter. Other detections of chlorinated compounds included trichloroethene, perchloroethene, cis-1,2-dichloroethene, 1,1,1-trichloroethane and chloroform.

  19. The use of volcanic soil as mineral landfill liner--I. Physicochemical characterization and comparison with zeolites.

    PubMed

    Navia, Rodrigo; Hafner, Georg; Raber, Georg; Lorber, Karl E; Schöffmann, Elke; Vortisch, Walter

    2005-06-01

    The main physicochemical characteristics of the volcanic soil of Southern Chile, with allophane as the main pedogenic mineral phase were analysed and compared with common zeolites (clinoptilolite) of the European market. The ultimate goal of this study was to test volcanic soil for the use as mineral landfill liner. The main results indicated that the clay and silt fractions together of the volcanic soil were between 38 and 54%. The buffering capacity of the volcanic soil was higher compared with the studied zeolites, whereas the cationic exchange capacity of the volcanic soil (between 5.2 and 6.5 cmol + kg(-1)) is of the same order of magnitude of the studied zeolites (between 9.7 and 11.4 cmol + kg(-1)). Moreover, the anionic exchange capacity of the volcanic soil was higher compared to the zeolites analysed. The hydraulic conductivity of the volcanic soil, measured in the laboratory at maximum proctor density, ranges between 5.16 x 10(-9) and 6.48 x 10(-9) m s(-1), a range that is comparable to the value of 4.51 x 10(-9) m s(-1) of the studied zeolite. The Proctor densities of the volcanic soil are in a lower range (between 1.11 and 1.15 g ml(-1)) compared with zeolites (between 1.19 and 1.34 g ml(-1)). The volcanic soil physicochemical characteristics are comparable to all the requirements established in the Austrian landfill directive (DVO, 2000). Therefore, the use as mineral landfill basal sealing of the analysed volcanic soil appears reasonable, having a pollutant adsorption capacity comparable to zeolites. It is of special interest for Southern Chile, because there are no alternative mineral raw materials for basal liners of landfills. PMID:15988944

  20. Passive soil venting at the Chemical Waste Landfill Site at Sandia National Laboratories, Albuquerque, New Mexico

    SciTech Connect

    Phelan, J.M.; Reavis, B.; Cheng, W.C.

    1995-05-01

    Passive Soil Vapor Extraction was tested at the Chemical Waste Landfill (CWL) site at Sandia National Laboratories, New Mexico (SNLIW). Data collected included ambient pressures, differential pressures between soil gas and ambient air, gas flow rates into and out of the soil and concentrations of volatile organic compounds (VOCS) in vented soil gas. From the differential pressure and flow rate data, estimates of permeability were arrived at and compared with estimates from other studies. Flow, differential pressure, and ambient pressure data were collected for nearly 30 days. VOC data were collected for two six-hour periods during this time. Total VOC emissions were calculated and found to be under the limit set by the Resource Conservation and Recovery Act (RCRA). Although a complete process evaluation is not possible with the data gathered, some of the necessary information for designing a passive venting process was determined and the important parameters for designing the process were indicated. More study is required to evaluate long-term VOC removal using passive venting and to establish total remediation costs when passive venting is used as a polishing process following active soil vapor extraction.

  1. Cover crops effectiveness for soil erosion control in Sicilian vineyard

    NASA Astrophysics Data System (ADS)

    Gristina, L.; Novara, A.; Saladino, S.; Santoro, A.

    2009-04-01

    In vineyards, which are very common in Mediterranean area, cover crops are becoming increasingly used to reduce soil erosion. Cover crops reduce runoff by increasing infiltration and increasing roughness and then reducing the ovelandflow velocity. The aim of the present study was to quantify soil and water losses under different soil managements systems on vineyards. The study site was a Sauvignon blanc winegrape vineyard located in Southwestern Sicily. Vineyards were managed both traditionally (conventional tillage) and alternative management using cover crops: 1) Vicia faba ; 2) Vicia faba and Vicia sativa; 3) Trifolium subterraneum, Lolium perenne, Festuca rubra; 4)Trifolium subterraneum, Festuca rubra and Festuca ovina, 5) Triticum durum, 6) Triticum durum and Vicia sativa. To monitor water and sediment yield, a Gerlach trough was installed at each treatment on the vineyard inter-row, with the row vineyard used as a border (topographical border). Runoff was measured after each rainfall event (raingauge 0.2 mm accuracy) from November 2005 to April 2007. And sediments were measured after desiccation. The results show that runoff and erosion were reduced considerably under the treatments with Trifolium subterraneum, Lolium perenne, Festuca rubra and Trifolium subterraneum, Festuca rubra and Festuca ovina (treatments 3 and 4). The soil losses were reduced by 73% under treatment 4 compared to the tillage plot. Conventional tillage and alternative management using Vicia faba cover crop (treatment 1) result the most ineffective treatment to soil erosion. These results show that the use of a cover crop can be a simple soil and water conservation practice in Sicilian vineyards. Key words: soil erosion, cover crops, vineyard, Mediterranean area.

  2. Analysis of landfills with historic airphotos

    NASA Technical Reports Server (NTRS)

    Erb, T. L.; Philipson, W. R.; Teng, W. L.; Liang, T.

    1981-01-01

    An investigation is conducted regarding the value of existing aerial photographs for waste management, including landfill monitoring. The value of historic aerial photographs for documenting landfill boundaries is shown in a graph in which the expansion of an active landfill is traced over a 40-year period. Historic aerial photographs can also be analyzed to obtain general or detailed land-use and land-cover information. In addition, the photographs provide information regarding other elements of the physical environment, including geology, soils, and surface and subsurface drainage. The value of historic photos is discussed, taking into account applications for inventory, assessing contamination/health hazards, planning corrective measures, planning waste collection and facilities, developing inactive landfills, and research concerning improved land-filling operations.

  3. Coupled Environmental Processes and Long-term Performance of Landfill Covers in the northern Mojave Desert

    SciTech Connect

    David Shafer; Michael Young; Stephen Zitzer; Eric McDonald; Todd Caldwell

    2004-05-12

    Evapotransiration (ET) covers have gained widespread acceptance as a closure feature for waste disposal sites, particularly in the arid and semi-arid regions of the southwestern U.S. But as landforms, ET covers are subject to change over time because of processes such as pedogenesis, hydrologic processes, vegetation establishment and change, and biological processes. To better understand the effects of coupled process changes to ET covers, a series of four primary analog sites in Yucca Flat on the Nevada Test Site, along with measurements and observations from other locations in the Mojave Desert, were selected to evaluate changes in ET covers over time. The analog sites, of varying ages, were selected to address changes in the early post-institutional control period, the 1,000-year compliance period for disposal of low-level and mixed low-level waste, and the 10,000-year compliance period for transuranic waste sites.

  4. Assessment of soil-gas contamination at the 17th Street landfill, Fort Gordon, Georgia, 2011

    USGS Publications Warehouse

    Falls, W. Fred; Caldwell, Andral W.; Guimaraes, Wladmir G.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

    2012-01-01

    Assessments of contaminants in soil gas were conducted in two study areas at Fort Gordon, Georgia, in July and August of 2011 to supplement environmental contaminant data for previous studies at the 17th Street landfill. The two study areas include northern and eastern parts of the 17th Street landfill and the adjacent wooded areas to the north and east of the landfill. These study areas were chosen because of their close proximity to the surface water in Wilkerson Lake and McCoys Creek. A total of 48 soil-gas samplers were deployed for the July 28 to August 3, 2011, assessment in the eastern study area. The assessment mostly identified detections of total petroleum hydrocarbons (TPH), and gasoline- and diesel-range compounds, but also identified the presence of chlorinated solvents in six samplers, chloroform in three samplers, 2-methyl naphthalene in one sampler, and trimethylbenzene in one sampler. The TPH masses exceeded 0.02 microgram (μg) in all 48 samplers and exceeded 0.9 μg in 24 samplers. Undecane, one of the three diesel-range compounds used to calculate the combined mass for diesel-range compounds, was detected in 17 samplers and is the second most commonly detected compound in the eastern study area, exceeded only by the number of TPH detections. Six samplers had detections of toluene, but other gasoline compounds were detected with toluene in three of the samplers, including detections of ethylbenzene, meta- and para-xylene, and octane. All detections of chlorinated organic compounds had soil-gas masses equal to or less than 0.08 μg, including three detections of trichloroethene, three detections of perchloroethene, three chloroform detections, one 1,4-dichlorobenzene detection, and one 1,1,2-trichloroethane detection. Three methylated compounds were detected in the eastern study area, but were detected at or below method detection levels. A total of 32 soil-gas samplers were deployed for the August 11–24, 2011, assessment in the northern study area. All samplers in the survey had detections of TPH, but only eight of the samplers had detections of TPH greater than 0.9 mg. Four samplers had TPH detections greater than 9 mg; the only other fuel-related compounds detected in these four samplers included toluene in three of the samplers and undecane in the fourth sampler. Three samplers deployed along the western margin of the northern landfill had detections of both diesel-and gasoline-related compounds; however, the diesel-related compounds were detected at or below method detection levels. Seven samplers in the northern study area had detections of chlorinated compounds, including three perchloroethene detections, three chloroform detections, and one 1,4-dichloro-benzene detection. One sampler on the western margin of the landfill had detections of 1,2,4-trimethylbenzene and 1,3,5-tr-methylbenene below method detection levels.

  5. INFLUENCE OF COVER CROPS AND SOIL AMENDMENTS ON OKRA (ABELMOSCHUS ESCULENTUS L.) PRODUCTION AND SOIL NEMATODES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A pot experiment to determine the effects of summer cover crops and soil amendments on okra yield and population densities of various soil nematode taxa was conducted in two consecutive growing seasons in a subtropical region. Two cover crops, sunn hemp (Crotalaria juncea) and sorghum sudangrass (So...

  6. Irrigating poplar energy crops with landfill leachate negatively affects soil micro- and meso-fauna.

    PubMed

    Coyle, David R; Zalesny, Jill A; Zalesny, Ronald S; Wiese, Adam H

    2011-10-01

    Increased municipal solid waste generated worldwide combined with substantial demand for renewable energy has prompted testing and deployment of woody feedstock production systems that reuse and recycle wastewaters as irrigation and fertilization. Populus selections are ideal for such systems given their fast growth, extensive root systems, and high water usage rates. Maintaining ecological sustainability (i.e., the capacity for an ecosystem to maintain its function and retain its biodiversity over time) during tree establishment and development is an important component of plantation success, especially for belowground faunal populations. To determine the impact of solid waste leachate on soil micro- and meso-fauna, we compared soilfrom eight different Populus clones receiving municipal solid waste landfill leachate irrigation with clones receiving fertilized (N, P K) well water irrigation. Microfauna (i.e., nematodes) communities were more diverse in control soils. Mesofauna (i.e., insects) were associated with all clones; however, they were four times more abundant around trees found within the control plot than those that received leachate treatments. Nematode and insect abundance varied among Populus clones yet insect diversity was greater in the leachate-treated soils. Phytotechnologies must allow for soil faunal sustainability, as upsetting this balance could lead to great reductions in phytotechnology efficacy. PMID:21972508

  7. Relic components within the soil cover of Mexico: regional variability

    NASA Astrophysics Data System (ADS)

    Solleiro Rebolledo, Elizabeth; Sedov, Sergey

    2015-04-01

    The case of paleosols persisting on the land surface (non-buried paleosols or relict soils) besides paleoecological interest has specific implications for studies of soil geography, ecology and management. In fact these soil bodies form part of the modern soil mantle and provide ecological services for the current (agro)ecosystems but are neither formed nor re-produced by these ecosystems, conforming locally extinct soils (although similar profiles can develop at present under other bioclimatic conditions). In consequence, they are a heritage of past climatic and biotic conditions now extinct, thus presenting a non-restorable component of the present landscape. Mexico has so abundant and diverse paleosols, both surface and buried, that really could be considered to be a "paleopedological paradise". Two groups of factors promote generation of this abundance: Major part of territory of Mexico is occupied by mountainous landscapes with high intensity of tectonic, volcanic and geomorphic processes. These processes create a complex mosaic of geological materials and landforms of different age (like alluvial and lake terraces, eroded slopes, and volcanic deposits of various eruptions). Meanwhile younger landsurfaces are occupied by the recently developed soils, the older ones could bear the relict soil bodies. The same processes produce sedimentary strata (alluvial, colluvial, pyroclastic, etc.) which frequently cover the pre-existing landsurfaces and soils, producing series of buried paleosols. In this work we present three study cases of relict paleosols that are integrated to the modern soil cover of Mexico: the case of reddish-brown soils in the arid landscapes of Sonora (in the north); the pedosediments (tepetates) in central Mexico; and the red soils developed under humid conditions in Yucatan (in the south).

  8. Beneficial uses of recycled asphalt-stabilized products as landfill cover and capping systems

    SciTech Connect

    Camougis, G.

    1996-12-31

    The American Reclamation Corporation (AMREC{reg_sign}) has played a major role in the development of new programs for the recycling of discarded materials from construction, demolition, remediation and manufacturing operations. Excavated petroleum-contaminated soils (oily soils), asphalt paving, concrete rubble, and discarded asphalt roofing shingles have been processed and recycled into beneficially useful construction products. AMREC uses a cold-mix, asphalt-emulsion technology to process many of the recyclables received at its recycling facility in Charlton, MA. Recyclable materials are processed and blended to produce recycled, asphalt-stabilized products. In addition, recycled, asphalt-stabilized products are being investigated and tested for other beneficial uses. This includes their uses as capping materials and as containment materials.

  9. Hydrological Perturbations Drive Biogeochemical Processes in Experimental Soil Columns from the Norman Landfill Site

    NASA Astrophysics Data System (ADS)

    Arora, B.; Mohanty, B. P.; McGuire, J. T.

    2010-12-01

    Fate and transport of contaminants in saturated and unsaturated zones is governed by biogeochemical processes that are complex and non-linearly coupled to each other. A fundamental understanding of the interactions between transport and reaction processes is essential to better characterize contaminant movement in the subsurface. The objectives of this study are to: i) develop quantitative relationships between hydrological (initial and boundary conditions, hydraulic conductivity ratio, and soil layering), geochemical (mineralogy, surface area, redox potential, and organic matter) and microbiological factors (MPN) that alter the biogeochemical processes, and ii) characterize the effect of hydrologic perturbations on coupled processes occurring at the column scale. The perturbations correspond to rainfall intensity, duration of wet and dry conditions, and water chemistry (pH). Soils collected from two locations with significantly different geochemistry at the Norman landfill site are used in this study. Controlled flow experiments were conducted on: i) two homogeneous soil columns, ii) a layered soil column, iii) a soil column with embedded clay lenses, and iv) a soil column with embedded clay lenses and one central macropore. Experimental observations showed enhanced biogeochemical activity at the interface of the layered and lensed columns over the texturally homogeneous soil columns. Multivariate statistical analysis showed that the most important processes were microbial reduction of Fe(III) and SO42-, and oxidation of reduced products in the columns. Modeling results from HP1 indicate least redox activity in the homogeneous sand column while the structurally heterogeneous columns utilize oxygen and nitrate from recharge as well as iron sulfide minerals already present in the columns as electron acceptors. Furthermore, the interface of the layered and lensed soil columns acts as a hotspot of biogeochemical activity due to increased transport timescale as a result of reduced hydraulic conductivity of loam and clay in these columns. Although the coupled HP1 model was able to effectively capture redox dynamics in the experimental soil columns, findings suggest the need to incorporate: i) reduction in hydraulic conductivity due to the formation of iron sulfide precipitates, and ii) transport of aqueous iron sulfide clusters observed in all columns except homogeneous sand in such contaminant fate and transport models. Results indicate that textural differences across the layered, lensed, and macropore columns were directly responsible for redox gradient across these interfaces. Also, quantitative relationships observed between pH and total carbon, pe and redox couples, etc. are most significantly affected by wetting and drying cycles of the soil moisture regime for the different soil columns.

  10. Barometric pumping of burial trench soil gases into the atmosphere at the 740-G Sanitary Landfill. Revision 1

    SciTech Connect

    Wyatt, D.E.; Pirkle, R.J.; Masdea, D.J.

    1992-12-01

    In 1991, a soil gas survey was performed at the Savannah River Site Sanitary Landfill as part of the characterization efforts required under the integrated Resource Conservation and Recovery Act (RCRA) Facility Investigation and Comprehensive Environmental Resource Conservation and Recovery Act (CERCLA) Remedial Investigation (RFI/RI) program. This report details the findings of this survey, which identified several areas of the landfill that were releasing volatile organic compounds to the atmosphere at levels exceeding regulatory standards. Knowledge of the rates of VOC outgassing is necessary to protect site workers, provide input into the human health and environmental risk assessment documents and provide input into the remedial design scenario.

  11. Soil Nitrogen Response to Coupling Cover Crops with Manure Injection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Coupling winter small grain cover crops (CC) with manure (M) application may increase retention of manure nitrogen (N) in corn-soybean cropping systems. The objective of this research was to quantify soil N changes after application of liquid swine M (Sus scrofa L.) at target N rates of 112, 224, an...

  12. Coupling Cover Crops and Manure Injection: Soil Inorganic N Changes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Integration of a rye/oat cover crop with liquid swine manure application may enhance retention of manure nitrogen (N) in corn-soybean cropping systems. The objective of this study was to evaluate changes in soil inorganic N following injection of liquid swine manure to plots seeded with a rye/oat co...

  13. Carbon storage in a heavy clay soil landfill site after biosolid application.

    PubMed

    Bolan, N S; Kunhikrishnan, A; Naidu, R

    2013-11-01

    Applying organic amendments including biosolids and composts to agricultural land could increase carbon (C) storage in soils and contribute significantly to the reduction of greenhouse gas emissions. Although a number of studies have examined the potential value of biosolids as a soil conditioner and nutrient source, there has been only limited work on the impact of biosolid application on C sequestration in soils. The objective of this study was to examine the potential value of biosolids in C sequestration in soils. Two types of experiments were conducted to examine the effect of biosolid application on C sequestration. In the first laboratory incubation experiment, the rate of decomposition of a range of biosolid samples was compared with other organic amendments including composts and biochars. In the second field experiment, the effect of biosolids on the growth of two bioenergy crops, Brassica juncea (Indian mustard) and Helianthus annuus (sunflower) on a landfill site was examined in relation to biomass production and C sequestration. The rate of decomposition varied amongst the organic amendments, and followed: composts>biosolids>biochar. There was a hundred fold difference in the rate of decomposition between biochar and other organic amendments. The rate of decomposition of biosolids decreased with increasing iron (Fe) and aluminum (Al) contents of biosolids. Biosolid application increased the dry matter yield of both plant species (by 2-2.5 fold), thereby increasing the biomass C input to soils. The rate of net C sequestration resulting from biosolid application (Mg C ha(-1) yr(-1) Mg(-1) biosolids) was higher for mustard (0.103) than sunflower (0.087). Biosolid application is likely to result in a higher level of C sequestration when compared to other management strategies including fertilizer application and conservation tillage, which is attributed to increased microbial biomass, and Fe and Al oxide-induced immobilization of C. PMID:23380138

  14. Kinetics of biological methane oxidation in the presence of non-methane organic compounds in landfill bio-covers

    SciTech Connect

    Albanna, Muna; Warith, Mostafa; Fernandes, Leta

    2010-02-15

    In this experimental program, the effects of non-methane organic compounds (NMOCs) on the biological methane (CH{sub 4}) oxidation process were examined. The investigation was performed on compost experiments incubated with CH{sub 4} and selected NMOCs under different environmental conditions. The selected NMOCs had different concentrations and their effects were tested as single compounds and mixtures of compounds. The results from all experimental sets showed a decrease in CH{sub 4} oxidation capacity of the landfill bio-cover with the increase in NMOCs concentrations. For example, in the experiment using compost with 100% moisture content at 35 deg. C without any NMOCs the V{sub max} value was 35.0 mug CH{sub 4}h{sup -1}g{sub wetwt}{sup -1}. This value was reduced to 19.1 mug CH{sub 4}h{sup -1}g{sub wetwt}{sup -1} when mixed NMOCs were present in the batch reactors under the same environmental conditions. The experimental oxidation rates of CH{sub 4} in the presence of single and mixed NMOCs were modeled using the uncompetitive inhibition model and kinetic parameters, including the dissociation constants, were obtained. Additionally, the degradation rates of the NMOCs and co-metabolic abilities of methanotrophic bacteria were estimated.

  15. Oxygen diffusion through soil covers on sulphidic mine tailings

    SciTech Connect

    Yanful, E.K. . Mineral Science Lab.)

    1993-08-01

    Engineered soil covers are being evaluated under Canada's Mine Environment Neutral Drainage (MEND) program for their effectiveness in preventing and controlling acid generation in sulfidic mill tailings. A critical parameter for predicting the performance of these covers is the diffusion coefficient of gaseous oxygen in the cover materials. Laboratory experiments conducted to determine the effective diffusion coefficient of a candidate cover material, a glacial till from an active mine site, are described. The diffusion coefficient is determined by fitting a semianalytic solution of the one-dimensional, transient diffusion equation to experimental gaseous oxygen concentration versus time graphs. Effective diffusion coefficients determined at high water saturations (85%--95%) were of the order of 8 [times] 10[sup [minus]8] m[sup 2]/s. The diffusion coefficients decreased with increase in water saturation as a result of the low diffusivity of gaseous oxygen in water relative to that in air and the low solubility of oxygen in water. Placement of soil covers in high saturation conditions would ensure that the flux of oxygen into tailings underneath such covers is low, resulting in low acid flux. This is confirmed by combined laboratory, field, and modeling studies.

  16. Radon diffusion in candidate soils for covering uranium mill tailings

    SciTech Connect

    Silker, W.B.; Kalkwarf, D.R.

    1983-04-01

    Diffusion coefficients were measured for radon in 34 soils that had been identified by mill personnel as candidate covers for their tailings piles in order to reduce radon emission. These coefficients referred to diffusion in the total pore space of the soils. They were measured in the laboratory by a steady-state method using soil columns compacted to greater than 80% of their Proctor maximum packing densities but with moisture contents generally less than would be expected at a tailings site. An empirical equation was used to extrapolate measured coefficients to value expected at soil-moisture contents representative of tailings sites in the western United States. Extrapolated values for silty sands and clayey sands ranged from 0.004 to 0.06 cm/sup 2//s. Values for inorganic silts and clays ranged from 0.001 to 0.02 cm/sup 2//s.

  17. [Investigation of polarization characteristics of soil surface with low vegetation cover and different soil moisture].

    PubMed

    Zhang, Qiao; Sun, Xiao-bing; Hong, Jin

    2010-11-01

    Compared with the spectral detection method, polarization detection could obtain more information of the target. For example, the polarization detection could be applied to interpret the refractive index and the surface roughness of the object, or retrieve the soil moisture, etc. Polarization detection provides a new approach to quantitative retrieval of soil moisture, and this is very important in agriculture, hydrology, meteorology and ecology. The polarization characteristics of soil surface with low vegetation cover,which is a example of mixed pixel in remote sensing, were researched with experiments, and the relationship between the polarization characteristics and soil moisture was also explored. The results showed that the polarization characteristics of soil surface with low vegetation cover are mainly determined by the area of bare soil, and are strongly relevant with the soil moisture. For the results of experiments in this paper, the IDOLP of soil surface with low vegetation cover increased with increasing soil moisture when the viewing angle of instrument was between 20 degree and 60 degree, while the incident angle of light source was fixed at 40 degree. This paper offered a new method to retrieve moisture content of soil with low vegetation cover. PMID:21284189

  18. Evaporative losses from soils covered by physical and different types of biological soil crusts

    USGS Publications Warehouse

    Chamizo, S.; Cantn, Y.; Domingo, F.; Belnap, J.

    2013-01-01

    Evaporation of soil moisture is one of the most important processes affecting water availability in semiarid ecosystems. Biological soil crusts, which are widely distributed ground cover in these ecosystems, play a recognized role on water processes. Where they roughen surfaces, water residence time and thus infiltration can be greatly enhanced, whereas their ability to clog soil pores or cap the soil surface when wetted can greatly decrease infiltration rate, thus affecting evaporative losses. In this work, we compared evaporation in soils covered by physical crusts, biological crusts in different developmental stages and in the soils underlying the different biological crust types. Our results show that during the time of the highest evaporation (Day 1), there was no difference among any of the crust types or the soils underlying them. On Day 2, when soil moisture was moderately low (11%), evaporation was slightly higher in well-developed biological soil crusts than in physical or poorly developed biological soil crusts. However, crust removal did not cause significant changes in evaporation compared with the respective soil crust type. These results suggest that the small differences we observed in evaporation among crust types could be caused by differences in the properties of the soil underneath the biological crusts. At low soil moisture (<6%), there was no difference in evaporation among crust types or the underlying soils. Water loss for the complete evaporative cycle (from saturation to dry soil) was similar in both crusted and scraped soils. Therefore, we conclude that for the specific crust and soil types tested, the presence or the type of biological soil crust did not greatly modify evaporation with respect to physical crusts or scraped soils.

  19. Fate and distribution of nitrogen in soil and plants irrigated with landfill leachate.

    PubMed

    Cheng, C Y; Chu, L M

    2011-06-01

    Landfill leachate contains a high concentration of ammoniacal substances which can be a potential supply of N for plants. A bioassay was conducted using seeds of Brassica chinensis and Lolium perenne to evaluate the phytotoxicity of the leachate sample. A soil column experiment was then carried out in a greenhouse to study the effect of leachate on plant growth. Two grasses (Paspalum notatum and Vetiver zizanioides) and two trees (Hibiscus tiliaceus and Litsea glutinosa) were irrigated with leachate at the EC50 levels for 12 weeks. Their growth performance and the distribution of N were examined and compared with columns applied with chemical fertilizer. With the exception of P. notatum, plants receiving leachate and fertilizer grew better than those receiving water alone. The growth of L. glutinosa and V. zizanioides with leachate irrigation did not differ significantly from plants treated with fertilizer. Leachate irrigation significantly increased the levels of NH(x)-N in soil. Although NO(x)-N was below 1 mg NL(-1) in the leachate sample, the soil NO(x)-N content increased by 9-fold after leachate irrigation, possibly as a result of nitrification. Leachate irrigation at EC50 provided an N input of 1920 kg N ha(-1) over the experimental period, during which up to 1050 kg N ha(-1) was retained in the soil and biomass, depending on the type of vegetation. The amount of nutrient added seems to exceed beyond the assimilative capability. Practitioners should be aware of the possible consequence of N saturation when deciding the application rate if leachate irrigation is aimed for water reuse. PMID:21349695

  20. Transient soil moisture profile of a water-shedding soil cover in north Queensland, Australia

    NASA Astrophysics Data System (ADS)

    Gonzales, Christopher; Baumgartl, Thomas; Scheuermann, Alexander

    2014-05-01

    In current agricultural and industrial applications, soil moisture determination is limited to point-wise measurements and remote sensing technologies. The former has limitations on spatial resolution while the latter, although has greater coverage in three dimensions, but may not be representative of real-time hydrologic conditions of the substrate. This conference paper discusses the use of elongated soil moisture probes to describe the transient soil moisture profile of water-shedding soil cover trial plots in north Queensland, Australia. Three-metre long flat ribbon cables were installed at designed depths across a soil cover with substrate materials from mining activities comprising of waste rocks and blended tailings. The soil moisture measurement is analysed using spatial time domain reflectometry (STDR) (Scheuermann et al., 2009) Calibration of the flat ribbon cable's soil moisture measurement in waste rocks is undertaken in a glasshouse setting. Soil moisture retention and outflows are monitored at specific time interval by mass balance and water potential measurements. These data sets together with the soil hydrologic properties derived from laboratory and field measurements are used as input in the numerical code on unsaturated flow, Hydrus2D. The soil moisture calculations of the glasshouse calibration using this numerical method are compared with results from the STDR soil moisture data sets. In context, the purpose of the soil cover is to isolate sulphide-rich mine wastes from atmospheric interaction as oxidation and leaching of these materials may result to acid and metalliferous drainage. The long term performance of a soil cover will be described in terms of the quantities and physico-chemical characteristics of its outflows. With the soil moisture probes set at automated and pre-determined measurement time intervals, it is expected to distinguish between macropore and soil moisture flows during high intensity rainfall events and, also continuously update data sets on soil moisture retention, especially during long periods of drought. As such, description of the soil cover water balance will be more elaborate as the soil moisture profile will be described in terms of temporal and spatial variability. Moreover, this field data set can lend support on the evaluation of the potential use of mine wastes as cover materials with respect to their hydrologic and geochemical properties.

  1. Space monitoring of municipal solid waste landfills in Kazakhstan

    NASA Astrophysics Data System (ADS)

    Skakova, Olga; Shagarova, Lyudmila

    Municipal solid waste (MSW) landfills are special facilities designed for waste isolation and disposal ensuring sanitary and epidemiological safety of population. A solid waste landfill is a complex object with its own specific features. Modern remote-sensing methods are an indispensable source of information for the analysis of space images of solid waste landfills in Kazakhstan. Space monitoring of solid waste landfills includes the following tasks: 1. Identification and mapping of landfill areas according to the data of remote earth sensing. 2. Studying of energy and structural characteristics of landfills based on remote sensing data. 3. Analysis of the state of landfills based on a comparison of current and archive remote sensing data. Space monitoring of territories of municipal solid waste landfills uses modern computer technologies. They include satellite imagery combined with sub-satellite research, as well as other sources of information used for identification and mapping of landfill territories. Investigation of municipal solid waste landfills requires targeted survey of landfill areas, remote sensing using operational and archival data including theoretical foundations of physical optics and statistical data. Processing of digital satellite information uses methods of pattern recognition, automated image processing and correlation analysis. Based on spectral energy and textural characteristics of municipal solid waste landfills obtained by remote sensing methods, the technology of space monitoring of landfill areas, including landfill recognition and characterization of solid waste landfills from remote observations was developed. Monitoring of MSW landfills uses satellite images of ultrahigh and medium spatial resolution. Medium-resolution images are used to determine temperature, vegetation cover and soil degradation. High-resolution images are used to detect landfills, to determine forms of soil degradation, to calculate geometrical parameters, and to evaluate measures of control over the operation of landfill areas. Therefore, the technology of monitoring of landfills, based on reception and processing of multispectral data of different spatial resolution in the specialized software, enables us to detect and to analyze MSW, and to assess their impact on the ecological state of the environment. The introduction of space-based monitoring of MSW will save material and financial resources aimed at identification of solid wastes, assessment of their state and evolution in space and time, especially on vast areas, for example, on the territory of the Republic of Kazakhstan.

  2. Bicultural legume-cereal cover crops for sustaining crop yields and improving soil and environmental quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cover crops, usually grown after the harvest of main crops in the fall to provide vegetative cover for reducing soil erosion, have many benefits in improving soil and environmental quality, besides sustaining crop yields. Cover crops use residual soil N and reduce NO3-N content in the soil profile, ...

  3. Replacing fallow with cover crops in a semiarid soil: effects on soil properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Replacement of fallow in crop-fallow systems with cover crops (CCs) may improve soil properties. We assessed whether replacing fallow in no-till winter wheat (Triticum aestivum L.)-fallow with winter and spring CCs for five years reduced wind and water erosion, increased soil organic carbon (SOC), a...

  4. Replacing fallow with cover crops in a semiarid soil:Effects on soil properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Replacement of fallow in cropfallow systems with cover crops (CCs) may improve soil properties. We assessed whether replacing fallow in no-till winter wheat (Triticum aestivum L.)fallow with winter and spring CCs for 5 years reduced wind and water erosion, increased soil organic carbon (SOC), and ...

  5. Soil phosphorous influence on growth and nutrition of tropical legume cover crops in acidic soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In tropical regions, the use of cover crops in crop production is an important strategy in maintaining sustainability of cropping systems. Phosphorus deficiency in tropical soils is one of the most yield limiting factors for successful production of cover crops. A greenhouse experiment was conduct...

  6. Soil carbon sequestration via cover crops- A meta-analysis

    NASA Astrophysics Data System (ADS)

    Poeplau, Christopher; Don, Axel

    2014-05-01

    Agricultural soils are depleted in soil organic carbon (SOC) and have thus a huge potential to sequester SOC. This can primarily be achieved by increasing carbon inputs into the soil. Replacing winter fallows by cover crop cultivation for green manure has many benefits for the soil and forms an additional carbon input. An increase in carbon concentration has been reported in several studies worldwide. However, the effect on SOC stocks, as well as the influence of environmental parameters and management on SOC dynamics is not known. We therefore conducted a meta-analysis to investigate those issues. A total of 33 studies, comprising 47 sites and 147 plots were compiled. A pedotransfer function was used to estimate bulk densities and calculate SOC stocks. SOC stock change was found to be a linear function of time since introduction, with an annual sequestration rate of 0.32 Mg C ha-1 yr-1. Since no saturation was visible in the observations, we used the model RothC to estimate a new steady state level and the resulting total SOC stock change for an artificial "average cropland". The total average SOC stock change with an annual input of 1.87 Mg C ha-1 yr-1 was 16.76 Mg C ha-1 for the average soil depth of 22 cm. We estimated a potential global SOC sequestration of 0.12±0.03 Pg C yr-1, which would compensate for 8 % of the direct annual greenhouse gas emissions from agriculture.

  7. Magnetic, geo-electric, and groundwater and soil quality analysis over a landfill from a lead smelter, Cairo, Egypt

    NASA Astrophysics Data System (ADS)

    Khalil, Mohamed H.

    2012-11-01

    A detailed ground magnetic survey, geoelectric vertical electric sounding (VES), and groundwater and soil quality analysis were conducted in the area of the abandoned landfill of the Awadallah lead (Pb) smelter, northeastern Cairo, Egypt. The integration between the applied techniques located successfully the buried solid waste, demarcated the groundwater and its possible contamination, and determined the lead level in soil. Magnetic survey comprised 50 magnetic profiles each 190 m length. Vertical derivatives, wavelength filters, and continuation filters characterized the eastern and central parts of the landfill by high intense magnetic anomalies reflecting metal and lead wastes, whereas the western part was characterized by low intense anomalies indicating change in the landfill composition to non-magnetized material. The geoelectric survey comprised 16 VES with a maximum AB/2 of 100 m. The inverted data demarcated effectively the groundwater aquifer with depth ranged from 11 to 18 m and true resistivities ranged from 96 to 118 Ω·m. The second layer (Holocene-Q3) of semi-permeable silty and sandy clay cap (true resistivities 29 ~ 51 Ω·m and thickness 9-17 m) constituted a considerable role in limiting the possible contamination from the landfill. The analyzed groundwater parameters pH, Eh, TDS, SEC, and DO indicated a good water quality with homogenous aquifer characteristics, whereas the lead concentration in groundwater (0.033-0.036 mg/L) was slightly exceeding the safe limits identified by the U.S. EPA (≤ 0.015 mg/L). Lead in soil samples revealed elevated concentrations (3130 mg/L/kg at VES-3) around the Awadallah smelter, whereas a gradual decrease in concentrations was recorded in the northwestern direction.

  8. Application of ecological risk assessment based on a novel TRIAD-tiered approach to contaminated soil surrounding a closed non-sealed landfill.

    PubMed

    Gutirrez, Laura; Garbisu, Carlos; Ciprin, Estela; Becerril, Jos M; Soto, Manu; Etxebarria, Javier; Madariaga, Juan M; Antigedad, Iaki; Epelde, Lur

    2015-05-01

    The Ecological Risk Assessment (ERA) is a reliable tool for communicating risk to decision makers in a comprehensive and scientific evidence-based way. In this work, a site-specific ERA methodology based on the TRIAD approach was applied to contaminated soil surrounding a closed non-sealed landfill, as a case study to implement and validate such ERA methodology in the Basque Country (northern Spain). Initially, the procedure consisted of the application of a Parameter Selection Module aimed at selecting the most suitable parameters for the specific characteristics of the landfill contaminated soil, taking into consideration the envisioned land use, intended ecosystem services and nature of contaminants. Afterwards, the selected parameters were determined in soil samples collected from two sampling points located downstream of the abovementioned landfill. The results from these tests were normalized to make them comparable and integrable in a risk index. Then, risk assessment criteria were developed and applied to the two landfill contaminated soil samples. Although the lack of a proper control soil was evidenced, a natural land use was approved by the ERA (at Tier 2) for the two landfill contaminated soils. However, the existence of a potential future risk resulting from a hypothetical soil acidification must be considered. PMID:25659305

  9. The Use of Biofilter to Reduce Atmospheric Global Warming Gas (CH4) Eemissions from Landfills

    NASA Astrophysics Data System (ADS)

    Park, S.; Thomas, J. C.; Brown, K. W.; Sung, K.

    2001-12-01

    The emission of greenhouse gasses resulting from anthropogenic activities is increasing the atmospheric concentration of these gases, which can influence the climatic system by changing the temperature, precipitation, wind and other climate factors. Methane (CH4) is a very potent greenhouse gas and CH4 emission from landfills in US has been reported as 37% of total anthropogenic source of CH4 emission. Properly designed soil biofilters may reduce atmospheric CH4 emissions from landfills and help reduce the accumulation of greenhouse gasses in the atmosphere. Biofilter performance was tested under a variety of environmental and design conditions. The results showed that biofilters have the potential to reduce CH4 emissions from landfills by as much as 83%. A quadratic equation was developed to describe the dependence of methane oxidation rate in a sandy loam textured soil as a function of soil temperature, soil moisture and ammonium nitrogen concentration. Using this equation and the averaged soil temperature and moisture contents, and census data for the largest cities of each of the 48 contiguous states, oxidation rates was calculated. A methane emission model was also developed to estimate the methane emission from municipal waste landfills with different covers. Older landfills with soil covers emitted an average of 83% of the generated CH4. Landfills with RCRA covers emitted 90% of the generated CH4 without biofilters and only 10% with biofilters. Thus, the installation of properly sized biofilters should significantly reduce atmospheric CH4 emissions from landfills.

  10. Gully potential in soil-covered uranium waste impoundments

    SciTech Connect

    Abt, S.R. . Dept. of Civil Engineering); Pauley, C.J. ); Hogan, S.A. ); Johnson, T.L. )

    1994-08-01

    Soil covers are routinely considered a design alternative to stabilize uranium waste impoundments. Gully intrusion into the cover is one of the greatest potential threats to the long-term stability of an impoundment. An investigation was conducted to estimate the maximum depth of gully intrusion, the approximate top width of the gully at the point of maximum incision, and the approximate location of the maximum intrusion. A large-scale laboratory study was conducted on seven embankments in which approximately 200 years of rainfall was simulated and the resulting gullies were documented. In addition, 11 gullies occurring in actual reclaimed impoundments were documented. An analysis of the laboratory and field data sets was performed in which the maximum depth of gully incision, top width of the gully, and location of the maximum gully incision were related to the pile height, tributary volume of runoff, and soil composition. These relations provide the designers with a means for assessing the cover design to meet the long-term stability of the waste.

  11. Vegetation study in support of the design and optimization of vegetative soil covers, Sandia National Laboratories, Albuquerque, New Mexico.

    SciTech Connect

    Peace, Gerald L.; Goering, Timothy James (GRAM inc., Albuquerque, NM); Knight, Paul J. (Marron and Associates, Albuquerque, NM); Ashton, Thomas S. (Marron and Associates, Albuquerque, NM)

    2004-11-01

    A vegetation study was conducted in Technical Area 3 at Sandia National Laboratories, Albuquerque, New Mexico in 2003 to assist in the design and optimization of vegetative soil covers for hazardous, radioactive, and mixed waste landfills at Sandia National Laboratories/New Mexico and Kirtland Air Force Base. The objective of the study was to obtain site-specific, vegetative input parameters for the one-dimensional code UNSAT-H and to identify suitable, diverse native plant species for use on vegetative soil covers that will persist indefinitely as a climax ecological community with little or no maintenance. The identification and selection of appropriate native plant species is critical to the proper design and long-term performance of vegetative soil covers. Major emphasis was placed on the acquisition of representative, site-specific vegetation data. Vegetative input parameters measured in the field during this study include root depth, root length density, and percent bare area. Site-specific leaf area index was not obtained in the area because there was no suitable platform to measure leaf area during the 2003 growing season due to severe drought that has persisted in New Mexico since 1999. Regional LAI data was obtained from two unique desert biomes in New Mexico, Sevilletta Wildlife Refuge and Jornada Research Station.

  12. Calculations of radar backscattering coefficient of vegetation-covered soils

    NASA Technical Reports Server (NTRS)

    Mo, T.; Schmugge, T. J.; Jackson, T. J. (Principal Investigator)

    1983-01-01

    A model for simulating the measured backscattering coefficient of vegetation-covered soil surfaces includes both coherent and incoherent components of the backscattered radar pulses from a rough sil surface. The effect of vegetation canopy scattering is also incorporated into the model by making the radar pulse subject to two-way attenuation and volume scattering when it passes through the vegetation layer. Model results agree well with the measured angular distributions of the radar backscattering coefficient for HH polarization at the 1.6 GHz and 4.75 GHz frequencies over grass-covered fields. It was found that the coherent scattering component is very important at angles near nadir, while the vegetation volume scattering is dominant at incident angles 30 degrees.

  13. Assessment of soil-gas, soil, and water contamination at the former 19th Street landfill, Fort Gordon, Georgia, 2009-2010

    USGS Publications Warehouse

    Falls, W. Fred; Caldwell, Andral W.; Guimaraes, Wladmir B.; Ratliff, W. Hagan; Wellborn, John B.; Landmeyer, James E.

    2011-01-01

    Soil gas, soil, and water were assessed for organic and inorganic constituents at the former 19th Street landfill at Fort Gordon, Georgia, from February to September 2010. Passive soil-gas samplers were analyzed to evaluate organic constituents in the hyporheic zone and flood plain of a creek and soil gas within the estimated boundaries of the former landfill. Soil and water samples were analyzed to evaluate inorganic constituents in soil samples, and organic and inorganic constituents in the surface water of a creek adjacent to the landfill, respectively. This assessment was conducted to provide environmental constituent data to Fort Gordon pursuant to requirements of the Resource Conservation and Recovery Act Part B Hazardous Waste Permit process. The passive soil-gas samplers deployed in the water-saturated hyporheic zone and flood plain of the creek adjacent to the former landfill indicated the presence of total petroleum hydrocarbon (TPH) and octane above method detection levels in groundwater beneath the creek bed and flood plain at all 12 soil-gas sampler locations. The TPH concentrations ranged from 51.4 to 81.4 micrograms per liter. Octane concentrations ranged from 1.78 to 2.63 micrograms per liter. These detections do not clearly identify specific source areas in the former landfill; moreover, detections of TPH and octane in a soil-gas sampler installed at a seep on the western bank of the creek indicated the potential for these constituents to be derived from source areas outside the estimated boundaries of the former landfill. A passive soil-gas sampler survey was conducted in the former landfill from June 30 to July 5, 2010, and involved 56 soil-gas samplers that were analyzed for petroleum and halogenated compounds not classified as chemical agents or explosives. The TPH soil-gas mass exceeded 2.0 micrograms in 21 samplers. Most noticeable are the two sites with TPH detections which are located in and near the hyporheic zone and are likely to affect the creek. However, most TPH detections were located in and immediately adjacent to a debris field located within the former landfill and in areas where debris was not visible, including the northwestern and southeastern parts of the study area. Two of the four soil-gas samplers installed within a former military training area adjacent to the landfill also had TPH detections above the method detection level. Benzene, toluene, ethylbenzene, and xylene (as combined BTEX mass) were detected at 0.02 microgram or greater in three soil-gas samplers installed at the northwestern boundary and in five samplers installed in the southeastern part of the study area. There was no BTEX mass detected above the method detection level in samplers installed in the debris field. Toluene was the most frequently detected BTEX compound. Compounds indicative of diesel-range organics were detected above 0.04 microgram in 12 soil-gas samplers and had a distribution similar to that of TPH, including being detected in the debris field. Undecane was the most frequently detected diesel compound. Chloroform and naphthalene were detected in eight and two soil-gas samplers, respectively. Five soil-gas samplers deployed during September 2010 were analyzed for organic compounds classified as chemical agents and explosives, but none exceeded the method detection levels. Five composite soil samples collected from within the estimated boundaries of the former landfill were analyzed for 35 inorganic constituents, but none of the constituents detected exceeded regional screening levels for industrial soils. The sample collected in the debris field exceeded background levels for aluminum, barium, calcium, chromium, lead, nickel, potassium, sodium, and zinc. Three surface-water samples were collected in September 2010 from a stormwater outfall culvert that drains to the creek and from the open channel of the creek at upstream and downstream locations relative to the outfall. Toluene was detected at 0.661 mi

  14. Potential for enhanced phytoremediation of landfills using biosolids--a review.

    PubMed

    Kim, Kwon-Rae; Owens, Gary

    2010-01-01

    Despite the use of recyclable materials increasing worldwide, waste disposal to landfill remains the most common method of waste management because it is simple and relatively inexpensive. Although landfill disposal is an effective waste management system, if not managed correctly, a number of potential detrimental environmental impacts have been identified including soil and ground water contamination, leachate generation, and gas emissions. In particular, improper post-closure treatment of landfills or deterioration of the conventional clay landfill capping were shown to result in land degradation which required remediation to secure contaminants within the landfill site. Phytoremediation is an attractive technology for landfill remediation, as it can stabilize soil and simultaneously remediate landfill leachate. In addition, landfill phytoremediation systems can potentially be combined with landfill covers (Phytocapping) for hydrological control of infiltrated rainfall. However, for the successful application of any phytoremediation system, the effective establishment of appropriate, desired vegetation is critical. This is because the typically harsh and sterile nature of landfill capping soil limits the sustainable establishment of vegetation. Therefore, the physicochemical properties of landfill capping soils often need to be improved by incorporating soil amendments. Biosolids are a common soil amendment and will often meet these demanding conditions because they contain a variety of plant nutrients such as nitrogen, phosphate, potassium, as well as a large proportion of organic matter. Such amendment will also ameliorate the physical properties of the capping soils by increasing porosity, moisture content, and soil aggregation. Contaminants which potentially originate from biosolids will also be remediated by activities congruent with the establishment of plants and bacteria. PMID:19939550

  15. Concentration and sources of polycyclic aromatic hydrocarbons (PAHs) and polychlorinated biphenyls (PCBs) in surface soil near a municipal solid waste (MSW) landfill.

    PubMed

    Melnyk, A; Dettlaff, A; Kukli?ska, K; Namie?nik, J; Wolska, L

    2015-10-15

    Due to a continuous demand of land for infrastructural and residential development there is a public concern about the condition of surface soil near municipal solid waste landfills. A total of 12 surface (0-20 cm) soil samples from a territory near a landfill were collected and the concentration of 16 PAHs and 7 PCB congeners were investigated in these samples. Limits of detection were in the range of 0.038-1.2 ?g/kg for PAHs and 0.025-0.041 ?g/kg for PCBs. The total concentration of ? PAHs ranged from 892 to 3514 ?g/kg with a mean of 1974 ?g/kg. The total concentration of ? PCBs ranged from 2.5 to 12 ?g/kg with a mean of 4.5 ?g/kg. Data analyses allowed to state that the PAHs in surface soils near a landfill were principally from pyrogenic sources. Due to air transport, PAHs forming at the landfill are transported outside the landfill. PCB origin is not connected with the landfill. Aroclor 1242 can be the source of PCBs in several samples. PMID:26026405

  16. [Effects of seasonal snow cover on soil nitrogen transformation in alpine ecosystem: a review].

    PubMed

    Liu, Lin; Wu, Yan; He, Yi-xin; Wu, Ning; Sun, Geng; Zhang, Lin; Xu, Jun-jun

    2011-08-01

    Seasonal snow cover has pronounced effects on the soil nitrogen concentration and transformation in alpine ecosystem. Snowfall is an important form of nitrogen deposition, which directly affects the content of soil available nitrogen. Different depths and different duration of snow cover caused by snowfall may lead the heterogeneity of abiotic factors (soil temperature and moisture) and biotic factors (soil microbes, alpine plants, and alpine animals), and further, produce complicated effects on the mineralization and immobilization of soil nitrogen. This paper introduced in emphasis the inherent mechanisms of soil nitrogen mineralization and leaching under the effects of frequent freeze-thaw events during the durative melting of snow cover, and summarized the main research results of field in situ experiments about the effects of seasonal snow cover on soil nitrogen in alpine ecosystem based on the possible changes in snow cover in the future. Some suggestions with regard to the effects of seasonal snow cover on soil nitrogen were put forward. PMID:22097387

  17. Estonian soil classification as a tool for recording information on soil cover and its matching with local site types, plant covers and humus forms classifications

    NASA Astrophysics Data System (ADS)

    Kõlli, Raimo; Tõnutare, Tõnu; Rannik, Kaire; Krebstein, Kadri

    2015-04-01

    Estonian soil classification (ESC) has been used successfully during more than half of century in soil survey, teaching of soil science, generalization of soil databases, arrangement of soils sustainable management and others. The Estonian normally developed (postlithogenic) mineral soils (form 72.4% from total area) are characterized by mean of genetic-functional schema, where the pedo-ecological position of soils (ie. location among other soils) is given by means of three scalars: (i) 8 stage lithic-genetic scalar (from rendzina to podzols) separates soils each from other by parent material, lithic properties, calcareousness, character of soil processes and others, (ii) 6 stage moisture and aeration conditions scalar (from aridic or well aerated to permanently wet or reductic conditions), and (iii) 2-3 stage soil development scalar, which characterizes the intensity of soil forming processes (accumulation of humus, podzolization). The organic soils pedo-ecological schema, which links with histic postlithogenic soils, is elaborated for characterizing of peatlands superficial mantle (form 23.7% from whole soil cover). The position each peat soil species among others on this organic (peat) soil matrix schema is determined by mean of 3 scalars: (i) peat thickness, (ii) type of paludification or peat forming peculiarities, and (iii) stage of peat decomposition or peat type. On the matrix of abnormally developed (synlithogenic) soils (all together 3.9%) the soil species are positioned (i) by proceeding in actual time geological processes as erosion, fluvial processes (at vicinity of rivers, lakes or sea) or transforming by anthropogenic and technological processes, and (ii) by 7 stage moisture conditions (from aridic to subaqual) of soils. The most important functions of soil cover are: (i) being a suitable environment for plant productivity; (ii) forming adequate conditions for decomposition, transformation and conversion of falling litter (characterized by humus cover type); (iii) being compartment for deposition of humus, individual organic compounds, plant nutrition elements, air and water, and (iv) forming (bio)chemically variegated active space for soil type specific edaphon. For studying of ESC matching with others ecosystem compartments classifications the comparative analysis of corresponding classification schemas was done. It may be concluded that forest and natural grasslands site types as well the plant associations of forests and grasslands correlate (match) well with ESC and therefore these compartments may be adequately expressed on soil cover matrixes. Special interest merits humus cover (in many countries known as humus form), which is by the issue natural body between plant and soil or plant cover and soil cover. The humus cover, which lied on superficial part of soil cover, has been formed by functional interrelationships of plants and soils, reflects very well the local pedo-ecological conditions (both productivity and decomposition cycles) and, therefore, the humus cover types are good indicators for characterizing of local pedo-ecological conditions. The classification of humus covers (humus forms) should be bound with soil classifications. It is important to develop a pedocentric approach in treating of fabric and functioning of natural and agro-ecosystems. Such, based on soil properties, ecosystem approach to management and protection natural resources is highly recommended at least in temperate climatic regions. The sound matching of soil and plant cover is of decisive importance for sustainable functioning of ecosystem and in attaining a good environmental status of the area.

  18. Amending metal contaminated mine soil with biochars to sequester metals and improve plant growth cover

    EPA Science Inventory

    There are numerous mine spoil sites in the U.S. Pacific Northwest that contain highly acidic, heavy metal-laden soils, which limits establishment of a soil-stabilizing plant cover. Biochars may be a suitable soil amendment to reduce toxic metals, improve soil fertility, soil wa...

  19. Comparison of two numerical modelling approaches to a field experiment of unsaturated radon transport in a covered uranium mill tailings soil (Lavaugrasse, France).

    PubMed

    Saâdi, Zakaria; Guillevic, Jérôme

    2016-01-01

    Uncertainties on the mathematical modelling of radon ((222)Rn) transport in an unsaturated covered uranium mill tailings (UMT) soil at field scale can have a great impact on the estimation of the average measured radon exhalation rate to the atmosphere at the landfill cover. These uncertainties are usually attributed to the numerical errors from numerical schemes dealing with soil layering, and to inadequate modelling of physical processes at the soil/plant/atmosphere interface and of the soil hydraulic and transport properties, as well as their parameterization. In this work, we demonstrate how to quantify these uncertainties by comparing simulation results from two different numerical models to experimental data of radon exhalation rate and activity concentration in the soil-gas measured in a covered UMT-soil near the landfill site Lavaugrasse (France). The first approach is based on the finite volume compositional (i.e., water, radon, air) transport model TOUGH2/EOS7Rn (Transport Of Unsaturated Groundwater and Heat version 2/Equation Of State 7 for Radon; Saâdi et al., 2014), while the second one is based on the finite difference one-component (i.e., radon) transport model TRACI (Transport de RAdon dans la Couche Insaturée; Ferry et al., 2001). Transient simulations during six months of variable rainfall and atmospheric air pressure showed that the model TRACI usually overestimates both measured radon exhalation rate and concentration. However, setting effective unsaturated pore diffusivities of water, radon and air components in soil-liquid and gas to their physical values in the model EOS7Rn, allowed us to enhance significantly the modelling of these experimental data. Since soil evaporation has been neglected, none of these two models was able to simulate the high radon peaks observed during the dry periods of summer. However, on average, the radon exhalation rate calculated by EOS7Rn was 34% less than that was calculated by TRACI, and much closer to the measured one for physically-based soil radon diffusion models. Unlike TRACI, EOS7Rn was able to simulate qualitatively seasonal variations of both radon exhalation and concentration. These results show that EOS7Rn produces less numerical errors than TRACI, and can be considered as a promising model for predicting radon transport in the landfill, if soil evaporation is modelled and its numerical inversion for parameter estimation is realized. PMID:25864040

  20. Estimation of municipal solid waste landfill settlement

    SciTech Connect

    Ling, H.I.; Leshchinsky, D.; Mohri, Yoshiyuki; Kawabata, Toshinori

    1998-01-01

    The municipal solid waste landfill suffers from large postclosure settlement that occurs over an extended period of time. A large differential settlement may impair foundations, utilities, and other associated facilities constructed on top of a landfill. It may also lead to breakage of the geomembrane and damage of the cover system in a modern municipal solid waste landfill. The waste material exhibits heterogeneous engineering properties that vary over locations and time within a landfill. These factors, combined with the fact that a landfill is not fully saturated, render a traditional soil mechanics approach less attractive for settlement prediction. An empirical approach of expressing settlement rate using logarithmic and power relationships is commonly used in conjunction with an observational procedure. In this paper, validity of these functions is reexamined based on published settlement results from three landfill sites. A hyperbolic function is proposed as an improved tool to simulate the settlement-time relationships, as well as to detect final settlement. The relationships between the parameters of these empirical functions and water content are examined.

  1. Land Cover Differences in Soil Carbon and Nitrogen at Fort Benning, Georgia

    SciTech Connect

    Garten Jr., C.T.

    2004-02-09

    Land cover characterization might help land managers assess the impacts of management practices and land cover change on attributes linked to the maintenance and/or recovery of soil quality. However, connections between land cover and measures of soil quality are not well established. The objective of this limited investigation was to examine differences in soil carbon and nitrogen among various land cover types at Fort Benning, Georgia. Forty-one sampling sites were classified into five major land cover types: deciduous forest, mixed forest, evergreen forest or plantation, transitional herbaceous vegetation, and barren land. Key measures of soil quality (including mineral soil density, nitrogen availability, soil carbon and nitrogen stocks, as well as properties and chemistry of the O-horizon) were significantly different among the five land covers. In general, barren land had the poorest soil quality. Barren land, created through disturbance by tracked vehicles and/or erosion, had significantly greater soil density and a substantial loss of carbon and nitrogen relative to soils at less disturbed sites. We estimate that recovery of soil carbon under barren land at Fort Benning to current day levels under transitional vegetation or forests would require about 60 years following reestablishment of vegetation. Maps of soil carbon and nitrogen were produced for Fort Benning based on a 1999 land cover map and field measurements of soil carbon and nitrogen stocks under different land cover categories.

  2. COVER CROPS ENHANCE SOIL ORGANIC MATTER, CARBON DYNAMICS AND MICROBIOLOGICAL FUNCTION IN A MEDITERRANEAN VINEYARD AGROECOSYSTEM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Impacts of soil tillage and cover crops on soil carbon (C) dynamics and microbiological function were investigated in a vineyard grown in California’s Mediterranean climate. We 1) compared soil organic matter (SOM), C dynamics and microbiological activity of two cover crops [Trios 102 (Triticale x T...

  3. Soil carbon accumulation after short-term use of rye as a winter cover crop

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of winter cover crops has been proposed to protect and enhance soil resources. Cereal rye (Secale cereale L.) can be an effective cover crop since it can produce large amounts of biomass in certain climates. However, short-term benefits of cover crop use on soil carbon accumulation are not w...

  4. Functional and environmental assessment of the urboecosystems designed in the biologically reclamated landfill with industrial wastes (in Ryazan city)

    NASA Astrophysics Data System (ADS)

    Karyakin, Alexey; Vasenev, Ivan; Karyakina, Svetlana

    2015-04-01

    Regional environmental bodies' ability to understand, model and predict their soil cover environmental functions are especially important in case of landfill reclamation. The special attention has to be done to landfills with industrial wastes created earlier in frame of big city - comparatively closed to their residential areas. Dominated in Ryazan region sandy loam gray forest soils with not so high soil organic matter content and soil exchange capacity determine additional problems with landfill biological reclamation and continuous sustainable vegetation cover development. The modern environmental monitoring system has been developed in the big landfill with tanning industrial wastes from the biggest in Europe tannery to develop recommendation on the environmentally friendly reclamation technologies adapted to concrete landscape conditions and functional features of 2 m fresh soil-ground coating the landfill surface. More detailed monitoring system has to be developed to assess the regulatory environmental functions of the regenerated soil cover to minimize the reclamated landfill' negative impacts on the urban ecosystem air, surface and ground water quality. Obtained result will be useful for similar landfills with tanning industrial wastes environmental impact assessment and smart design.

  5. Minimum depth of soil cover above long-span soil-steel railway bridges

    NASA Astrophysics Data System (ADS)

    Esmaeili, Morteza; Zakeri, Jabbar Ali; Abdulrazagh, Parisa Haji

    2013-12-01

    Recently, soil-steel bridges have become more commonly used as railway-highway crossings because of their economical advantages and short construction period compared with traditional bridges. The currently developed formula for determining the minimum depth of covers by existing codes is typically based on vehicle loads and non-stiffened panels and takes into consideration the geometrical shape of the metal structure to avoid the failure of soil cover above a soil-steel bridge. The effects of spans larger than 8 m or more stiffened panels due to railway loads that maintain a safe railway track have not been accounted for in the minimum cover formulas and are the subject of this paper. For this study, two-dimensional finite element (FE) analyses of four low-profile arches and four box culverts with spans larger than 8 m were performed to develop new patterns for the minimum depth of soil cover by considering the serviceability criterion of the railway track. Using the least-squares method, new formulas were then developed for low-profile arches and box culverts and were compared with Canadian Highway Bridge Design Code formulas. Finally, a series of three-dimensional (3D) finite element FE analyses were carried out to control the out-of-plane buckling in the steel plates due to the 3D pattern of train loads. The results show that the out-of-plane bending does not control the buckling behavior of the steel plates, so the proposed equations for minimum depth of cover can be appropriately used for practical purposes.

  6. Mobility of Pb, Cu, and Zn in the phosphorus-amended contaminated soils under simulated landfill and rainfall conditions.

    PubMed

    Cao, Xinde; Liang, Yuan; Zhao, Ling; Le, Huangying

    2013-09-01

    Phosphorus-bearing materials have been widely applied in immobilization of heavy metals in contaminated soils. However, the study on the stability of the initially P-induced immobilized metals in the contaminated soils is far limited. This work was conducted to evaluate the mobility of Pb, Cu, and Zn in two contrasting contaminated soils amended with phosphate rock tailing (PR) and triple superphosphate fertilizer (TSP), and their combination (P?+?T) under simulated landfill and rainfall conditions. The main objective was to determine the stability of heavy metals in the P-treated contaminated soils in response to the changing environment conditions. The soils were amended with the P-bearing materials at a 2:1 molar ratio of P to metals. After equilibrated for 2weeks, the soils were evaluated with the leaching procedures. The batch-based toxicity characteristic leaching procedure (TCLP) was conducted to determine the leachability of heavy metals from both untreated and P-treated soils under simulated landfill condition. The column-based synthetic precipitation leaching procedure (SPLP) were undertaken to measure the downward migration of metals from untreated and P-treated soils under simulated rainfall condition. Leachability of Pb, Cu, and Zn in the TCLP extract followed the order of Zn?>?Cu?>?Pb in both soils, with the organic-C- and clay-poor soil showing higher metal leachability than the organic-C- and clay-rich soil. All three P treatments reduced leachability of Pb, Cu, and Zn by up to 89.2, 24.4, and 34.3%, respectively, compared to the untreated soil, and TSP revealed more effectiveness followed by P?+?T and then PR. The column experiments showed that Zn had the highest downward migration upon 10 pore volumes of SPLP leaching, followed by Pb and then Cu in both soils. However, migration of Pb and Zn to subsoil and leachate were inhibited in the P-treated soil, while Cu in the leachate was enhanced by P treatment in the organic-C-rich soil. More than 73% P in the amendments remained in the upper 0-10cm soil layers. However, leaching of P from soluble TSP was significant with 24.3% of P migrated in the leachate in the organic-C-poor soil. The mobility of heavy metals in the P-treated soil varies with nature of P sources, heavy metals, and soils. Caution should be taken on the multi-metal stabilization since the P amendment may immobilize some metals while promoting others' mobility. Also, attention should be paid to the high leaching of P from soluble P amendments since it may pose the risk of excessive P-induced eutrophication. PMID:23263754

  7. Characterization of contaminated soil and groundwater surrounding an illegal landfill (S. Giuliano, Venice, Italy) by principal component analysis and kriging.

    PubMed

    Critto, Andrea; Carlon, Claudio; Marcomini, Antonio

    2003-01-01

    The characterization of a hydrologically complex contaminated site bordering the lagoon of Venice (Italy) was undertaken by investigating soils and groundwaters affected by the chemical contaminants originated by the wastes dumped into an illegal landfill. Statistical tools such as principal components analysis and geostatistical techniques were applied to obtain the spatial distribution of chemical contaminants. Dissolved organic carbon (DOC), SO4(2-) and Cl- were used to trace the migration of the contaminants from the top soil to the underlying groundwaters. The chemical and hydrogeological available information was assembled to obtain the schematic of the conceptual model of the contaminated site capable to support the formulation of major exposure scenarios, which are also provided. PMID:12531312

  8. The Challenges of Implementing Conservation Tillage and Cover Crops in Clay Soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conservation practices, such as reduced tillage and cover crops, can improve soil quality and increase soil moisture for crop production. Benefits to production, soil quality, and water conservation have been observed especially in areas with rapidly draining soils. While historically enjoying high ...

  9. Fall cover crops boost soil arbuscular mycorrhizal fungi which can lead to reduced inputs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fall cover crops provide multiple benefits to producers. These benefits include pathogen and pest protection, drought protection, weed control, reduced soil erosion, nutrient acquisition and retention, increased soil organic matter, and conservation of soil water by improvement of soil structure th...

  10. Soil organic carbon and water content effects on remote crop residue cover estimation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conservation tillage (CT) systems help protect the soil and environment, and improve net farm profitability. CT methods leave increased amounts of crop residue cover (CRC) on the soil surface, minimizing soil erosion and evaporation. CT uses less fuel, disturbs soil less, and requires less fertili...

  11. Summer cover crops and soil amendments to improve growth and nutrient uptake of okra

    SciTech Connect

    Wang, Q.R.; Li, Y.C.; Klassen, W.

    2006-04-15

    A pot experiment with summer cover crops and soil amendments was conducted in two consecutive years to elucidate the effects of these cover crops and soil amendments on 'Clemson Spineless 80' okra (Abelmoschus esculentus) yields and biomass production, and the uptake and distribution of soil nutrients and trace elements. The cover crops were sunn hemp (Crotalaria juncea), cowpea (Vigna unguiculata), velvetbean (Mucuna deeringiana), and sorghum sudan-grass (Sorghum bicolor x S. bicolor var. sudanense) with fallow as the control. The organic soil amendments were biosolids (sediment from wastewater plants), N-Viro Soil (a mixture of biosolids and coal ash), coal ash (a combustion by-product from power plants), co-compost (a mixture of 3 biosolids: 7 yard waste), and yard waste compost (mainly from leaves and branches of trees and shrubs, and grass clippings) with a soil-incorporated cover crop as the control. As a subsequent vegetable crop, okra was grown after the cover crops, alone or together with the organic soil amendments, had been incorporated. All of the cover crops, except sorghum sudangrass in 2002-03, significantly improved okra fruit yields and the total biomass production. Both cover crops and soil amendments can substantially improve nutrient uptake and distribution. The results suggest that cover crops and appropriate amounts of soil amendments can be used to improve soil fertility and okra yield without adverse environmental effects or risk of contamination of the fruit. Further field studies will be required to confirm these findings.

  12. The effects of different soil cover management practices on plant biodiversity and soil properties in Mediterranean ancient olive orchards

    NASA Astrophysics Data System (ADS)

    Madzaric, Suzana; Aly, Adel; Ladisa, Gaetano; Calabrese, Generosa

    2014-05-01

    The effects of different soil cover management practices on plant biodiversity and soil properties in Mediterranean ancient olive orchards Madzaric S., Aly A., Ladisa G. and Calabrese G. The loss of natural plant cover due to the inappropriate soil cover management is often a decisive factor for soil degradation in Mediterranean area. This accompanied with typical climate, characterized by cool, wet winters and hot and dry summers leads to soil erosion and loss of productivity. Due to simplification of agricultural practice and to the attempt to decrease cost of production, keeping soil bare is a widespread agricultural practice in Mediterranean ancient olive orchards (AOOs). The consequences of this are degradation of soil quality and reduction of plant biodiversity. In last year's some alternative practices are proposed in order to protect soil and biodiversity. One of these practices is the "grassing" i.e. covering the soil by selected autochthonous plant species. Objectives of our study are: (1) to evaluate impact of different soil cover management practices on soil properties and plant biodiversity in AOOs and (2) to define a minimum indicators' set (Minimum Data Set - MDS) to evaluate the effectiveness of different agricultural practices in environmental performance of AOOs. A comparison was carried on considering two management systems (conventional vs. organic) and three agricultural practices: conventional with bare soil (CON), organic with soil covered by selected autochthonous species (MIX) and organic left to the native vegetation (NAT). In general a clear positive influence of organic management system was recognized. Some soil quality indicators (physical, chemical and biological) showed responsiveness in describing the effects of management system and agricultural practices on soil properties. The both approaches with vegetation cover on the soil surface (either sowing of mixture or soil left to the natural plant cover) performed better than conventional one with repeated tillage and bare soil during the whole year. This is peculiarly visible in the case of soil erosion that presents an enormous problem in Mediterranean region. No clear differences resulted between the two organic practices for soil management (natural cover and grassing). Key words: organic agriculture, ecological indicators, agricultural practices, soil quality, olive groves

  13. The role of snow cover and soil freeze/thaw cycles affecting boreal-arctic soil carbon dynamics

    NASA Astrophysics Data System (ADS)

    Yi, Y.; Kimball, J. S.; Rawlins, M. A.; Moghaddam, M.; Euskirchen, E. S.

    2015-07-01

    Northern Hemisphere permafrost affected land areas contain about twice as much carbon as the global atmosphere. This vast carbon pool is vulnerable to accelerated losses through mobilization and decomposition under projected global warming. Satellite data records spanning the past 3 decades indicate widespread reductions (∼ 0.8-1.3 days decade-1) in the mean annual snow cover extent and frozen season duration across the pan-Arctic domain, coincident with regional climate warming trends. How the soil carbon pool responds to these changes will have a large impact on regional and global climate. Here, we developed a coupled terrestrial carbon and hydrology model framework with detailed 1-D soil heat transfer representation to investigate the sensitivity of soil organic carbon stocks and soil decomposition to changes in snow cover and soil freeze/thaw processes in the Pan-Arctic region over the past three decades (1982-2010). Our results indicate widespread soil active layer deepening across the pan-Arctic, with a mean decadal trend of 6.6 12.0 (SD) cm, corresponding with widespread warming and lengthening non-frozen season. Warming promotes vegetation growth and soil heterotrophic respiration, particularly within surface soil layers (? 0.2 m). The model simulations also show that seasonal snow cover has a large impact on soil temperatures, whereby increases in snow cover promote deeper (? 0.5 m) soil layer warming and soil respiration, while inhibiting soil decomposition from surface (? 0.2 m) soil layers, especially in colder climate zones (mean annual T ? -10 C). Our results demonstrate the important control of snow cover in affecting northern soil freeze/thaw and soil carbon decomposition processes, and the necessity of considering both warming, and changing precipitation and snow cover regimes in characterizing permafrost soil carbon dynamics.

  14. What's left? - Investigations on soil cover of conservation tillage methods in Austria

    NASA Astrophysics Data System (ADS)

    Bauer, Thomas; Hsl, Rosemarie; Strauss, Peter

    2014-05-01

    One of the most accepted and a practicable method to prevent soil from erosion is conservation tillage. If conservation tillage practices are performed in a proper way soil is protected from wind and water erosion. This study deals with the effectivity of conservation tillage practices under real field conditions. Therefore we i) carried out rainfall simulation experiments employing conservation tillage practices which had been proposed by farmers to test whether actual conservation tillage practices would be effective, ii) did an observation of mean soil cover on arable land after seeding in Lower and Upper Austria for field sites where conservation tillage was funded. Rainfall simulation experiments were carried out in the years 2011 and 2012 for various conservation tillage treatments consisting of different mulching and no tillage techniques. To evaluate results on surface runoff and erosion we additionally measured soil cover, bulk densities and surface roughness of the experimental plots. Soil cover estimation of the arable land in Lower and Upper Austria which is funded for conservation tillage practices was done in 2012 and 2013. Altogether on 146 randomly chosen field sites soil cover was estimated by using an object-based image analysis method. Results reveal that the effectiveness of conservation tillage was depending on the existence of a sufficient soil cover. However, under conditions of actual farm practices, a sufficient soil cover was not obtained for mulching treatments in 2011 and only partially in 2012. Therefore, mulching treatments partially gained even higher surface runoff and soil loss rates than conventional tillage practices. Due to their high soil cover, soil loss and surface runoff of no tillage treatments were very small as compared to all other tested treatments. The results of the soil cover estimation in Lower and Upper Austria show that under practicable land use a mean soil cover of 12 percent can be reached, what's rather low in a sense of soil erosion prevention compared to the results of our rainfall simulation experiments and literature.

  15. Cover Crop Effects on the Fate of Swine Manure-N Applied to Soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cereal grain cover crops increase surface cover, anchor corn and soybean residues, increase infiltration, reduce both rill and interrill erosion, scavenge excess nutrients from the soil, and are easily obtained and inexpensive compared to other cover crop options. The use of cereal grain cover crops...

  16. Migration and methanogens: A review of current landfill gas field research at ANL

    SciTech Connect

    Bogner, J.; Torpy, M.; Rose, C.; Vogt, M.; Gartman, D.; Moore, C.

    1986-01-01

    Landfill gas recovery research at Argonne National Laboratory is focusing on a project studying gas movement through landfill cover materials and a pilot investigation of microbial populations in landfills. Vertical gas pressure and concentration gradients between the top of refuse and the landfill cover are being examined. In particular, changes in the vertical gradients indicative of changes in magnitude and direction of pressure or diffusional flow with time are being monitored. This study emphasizes changes in vertical pressure and concentration gradients related to barometric pressure and other meteorological variables, soil moisture changes, and pumping rates at simulated recovery wells. Preliminary results suggest that changes in soil-gas pressures in the landfill cover and top of refuse closely follow changes in barometric pressure. Measurable concentration gradients exist between the top of refuse and the cover materials indicating that diffusion is a major mechanism for gas movement, particularly during dry weather when pressure gradients are negligible. A pilot investigation has begun on microbial populations in sanitary landfills. First, a series of leachate samples from various depths at the Blackwell Forest Preserve Landfill were evaluated for microbial populations, selected chemical constituents, and methane production. Diverse motile populations of fluorescing organisms were found in selected samples. 19 refs., 6 figs., 3 tabs.

  17. Leaky Landfills.

    ERIC Educational Resources Information Center

    Jones, Linda L. Cronin

    1992-01-01

    Provides background information on landfills and describes an activity where students learn how a modern landfill is constructed and develop an understanding of the reasons for several regulations regarding modern landfill construction. Students design and construct working models of three types of landfills. (PR)

  18. Landfill leachate treatment with a novel process: anaerobic ammonium oxidation (Anammox) combined with soil infiltration system.

    PubMed

    Liang, Zhu; Liu, Junxin

    2008-02-28

    A novel combined process was proposed to treat municipal landfill leachate with high concentrations of ammonium and organics. This process consisted of a partial nitritation reactor (PNR), an anaerobic ammonium oxidation (Anammox) reactor (AR) and two underground soil infiltration systems (USIS-1 and USIS-2). Based on the optimum operating conditions obtained from batch tests of individual unit, the combined process was continuously operated on a bench scale for 166 days. Partial nitritation was performed in a fixed bio-film reactor (PNR, working volume=12 L). Ammonium nitrogen-loading rate (Nv) and DO were combined to monitor partial nitritation, and at T=30+/-1 degrees C, Nv=0.27-1.2 kg/(m3.d), DO=0.8-2.3 mg/L, the ratios of nitrite nitrogen (NO2--N) to ammonium nitrogen (NH4+-N) were successfully kept close to 1.0-1.3 in the effluent. Nitrate nitrogen (NO3--N) less than 43 mg/L was observed. The effluent of PNR was ideally suited as influent of AR. Sixty-nine percent CODcr from the raw leachate was degraded in the PNR. Anammox was carried out in a fixed bio-film reactor (AR, working volume=36 L). At T=30+/-1 degrees C, Nv=0.06-0.11 kg/(m3.d), about 60% NH4+-N and 64% NO2--N in the influent of AR were simultaneously removed. Inhibition of high-strength NO2--N (up to 1011 mg/L) should be responsible for the low removal rate of nitrogen. About 35% aquatic humic substance (AHS) was degraded in the AR. With the same working volume (200 L), USIS-1 and USIS-2 were alternately performed to treat the effluent from AR at one cycle of about 30 days. At hydraulic loading rate (HLR)=0.02-0.04 m3/m3.d, pollutant loading rates (PLR)=NH4+-N

  19. Soil quality assessment for peat-mineral mix cover soil used in oil sands reclamation.

    PubMed

    Ojekanmi, A A; Chang, S X

    2014-09-01

    A soil quality (SQ) assessment and rating framework that is quantitative, iterative, and adaptable, with justifiable weighting for quality scores, is required for evaluating site-specific SQ at land reclamation sites. Such a framework needs to identify the minimum dataset that reflects the current knowledge regarding relationships between SQ indicators and relevant measures of ecosystem performance. Our objective was to develop nonlinear scoring functions for assessing the impact on SQ of peat-mineral mix (PMM) used as a cover soil at land reclamation sites. Soil functional indicators affected by PMM were extracted from existing databases and correlated with soil organic carbon (SOC). Based on defined objectives for SQ assessment, indicators with significant correlation ( < 0.05) to SOC were selected, normalized, and fitted to sigmoid functions using nonlinear regression procedure to establish SQ functions (SQFs) that can analyze changes in field capacity, permanent wilting point, soil nitrogen, and cation exchange capacity of PMM using SOC as input parameter. Application of the SQFs to an independent dataset produced ratings with mean differences similar to the treatment effects of mixing three levels of peat and mineral soil. These results show that derived ratings and weighing factors using SOC reflect the relationship between PMM treatment and other SQ indicators. Applying the developed SQFs to a long-term soil monitoring dataset shows that an increase or decrease in SOC from 10 to 20 g kg causes a significant change in SQ. This identifies the need for further nutrient and moisture management of PMM to support long-term SQ development in land reclamation. PMID:25603242

  20. Soil health benefits using cover crops across the Southeast

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soils in the southeastern U.S. are very low in organic matter, which can be attributed to high temperatures, humidity, and rainfall that oxidizes organic residues very quickly. Conventional tillage exacerbates this condition and generally contributes to poor soil health. As a result, soils in the r...

  1. Containment and attenuating layers: An affordable strategy that preserves soil and water from landfill pollution.

    PubMed

    Regadío, Mercedes; Ruiz, Ana I; Rodríguez-Rastrero, Manuel; Cuevas, Jaime

    2015-12-01

    The performance of a widely distributed natural clay to attenuate contaminants released from an old landfill was investigated. The objective is to evaluate its potential use as a barrier for waste containment systems. Core samples of the natural clay were collected below the landfill and their parameters distribution with depth was determined. Partition coefficients, retardation factors and percentage values of pollutants concentrations, revealed a rapid decrease of contaminants with depth. The background values of the pollutants were below the maximum limits for drinking and irrigation water and with no need of reactors, collectors, aeration or recirculation systems. Impermeable waste capping is discouraged in order to decrease leachate toxicity, decomposition time and conservative species, and in order to avoid high-reducing conditions that would mobilize redox-sensitive contaminants. A review on leachate-composition evolution and on natural-attenuation processes was undertaken to understand the interactions leachate-substratum, which is essential to properly estimate the leachate transport and implement the attenuation strategy. This strategy complements the traditional containment one regarding (1) the susceptibility of engineering liners to fail, (2) the inevitable diffusion of contaminants through them, (3) the remaining high number of old landfills before the requirements of liner systems and (4) the low-cost and feasibility for developing countries. PMID:26320817

  2. Soil cover patterns and land resources in the south of the Selenga mountainous region

    NASA Astrophysics Data System (ADS)

    Davydova, T. V.; Tsybzhitov, Ts. Kh.; Tsybikdorzhiev, Ts. Ts.; Gonchikov, B.-M. N.

    2009-04-01

    Soil cover patterns within the Kyakhta area of pine stands and the Kudarinsk area of dry steppes in the south of the Selenga mountainous region are characterized. The groups of soil combinations are shown on the map developed on a scale of 1: 500000. The areas of particular soils composing the combinations have been calculated. Thus, this small-scale soil map generally preserves information reflected on large- and medium-scale soil maps.

  3. [Nitrous oxide emissions from municipal solid waste landfills and its measuring methodology: a review].

    PubMed

    Jia, Ming-Sheng; Wang, Xiao-Jun; Chen, Shao-Hua

    2014-06-01

    Nitrous oxide (N2O) is one of three major greenhouse gases and the dominant ozone-depleting substance. Landfilling is the major approach for the treatment and disposal of municipal solid waste (MSW), while MSW landfills can be an important anthropogenic source for N2O emissions. Measurements at lab-scale and full-scale landfills have demonstrated that N2O can be emitted in substantial amounts in MSW landfills; however, a large variation in reported emission values exists. Currently, the mechanisms of N2O production and emission in landfills and its contribution to global warming are still lack of sufficient studies. Meanwhile, obtaining reliable N2O fluxes data in landfills remains a question with existing in-situ measurement techniques. This paper summarized relevant literature data on this issue and analyzed the potential production and emission mechanisms of N2O in traditional anaerobic sanitary landfill by dividing it into the MSW buried and the cover soil. The corresponding mechanisms in nitrogen removal bioreactor landfills were analyzed. Finally, the applicability of existing in-situ approaches measuring N2O fluxes in landfills, such as chamber and micrometeorological methods, was discussed and areas in which further research concerning N2O emissions in landfills was urgently required were proposed as well. PMID:25223043

  4. Radar backscattering measurement of bare soil and vegetation covered soil using X-band and full polarization

    NASA Astrophysics Data System (ADS)

    Goswami, B.; Kalita, M.

    2014-11-01

    The objective of the study is to measure backscattered power of bare soil and vegetation covered soil using X-band scatterometer system with full polarization and various angles during monsoon season and relate backscattered power to the density of vegetation over soil. The measurement was conducted at an experimental field located in the campus of Assam Engineering College, Guwahati, India. The soil sample consists of Silt and Clay in higher proportions as compared to Sand. The scatterometer system consists of dual-polarimetric square horn antennas, Power meter, Klystron, coaxial cables, isolator and waveguide detector. The polarization of the horn antennas as well as the look angle can be changed in the set-up. The backscattering coefficients were calculated by applying a radar equation for the measured values at incident angles between 30° and 60° for full polarization (HH, VV, HV, VH), respectively, and compared with vegetation cover over soil for each scatterometer measurement simultaneously. The VH polarization and 60° look angle are found to be the most suitable combination of configuration of an X-band scatterometer for distinguishing the land cover targets such as bare soil and vegetation covered soil. From the analysis of the results, polarimetric scatterometer data appear to be promising to distinguish the land cover types such as bare soil and soil completely covered by vegetation. The results of this study will help the scientists working in the field of active microwave remote sensing.

  5. Ruminant Grazing of Cover Crops: Effects on Soil Properties and Agricultural Production

    ERIC Educational Resources Information Center

    Poffenbarger, Hanna

    2010-01-01

    Integrating livestock into a cropping system by allowing ruminant animals to graze cover crops may yield economic and environmental benefits. The effects of grazing on soil physical properties, soil organic matter, nitrogen cycling and agricultural production are presented in this literature review. The review found that grazing cover crops

  6. Ruminant Grazing of Cover Crops: Effects on Soil Properties and Agricultural Production

    ERIC Educational Resources Information Center

    Poffenbarger, Hanna

    2010-01-01

    Integrating livestock into a cropping system by allowing ruminant animals to graze cover crops may yield economic and environmental benefits. The effects of grazing on soil physical properties, soil organic matter, nitrogen cycling and agricultural production are presented in this literature review. The review found that grazing cover crops…

  7. Installation of geosynthetic clay liners at California MSW landfills

    SciTech Connect

    Snow, M.; Jesionek, K.S.; Dunn, R.J.; Kavazanjian, E. Jr.

    1997-11-01

    The California regulations for liner systems at municipal solid waste (MSW) landfills require that alternatives to the prescriptive federal Subtitle D liner system have a containment capability greater than that of the prescriptive system. Regulators may also require a demonstration that use of the prescriptive system is burdensome prior to approval of an alternative liner design. This paper presents seven case histories of the design and installation of geosynthetic clay liners (GCL) as an alternative to the low-permeability soil component of the prescriptive Subtitle D composite liner system at MSW landfills in California. These case histories cover GCLs from different manufacturers and landfill sites with a wide range of conditions including canyon landfills with slopes as steep as 1H:1V.

  8. [Influence of Different Straws Returning with Landfill on Soil Microbial Community Structure Under Dry and Water Farming].

    PubMed

    Lan, Mu-ling; Gao, Ming

    2015-11-01

    Based on rice, wheat, corn straw and rape, broad bean green stalk as the research object, using phospholipid fatty acid (PLFA) method, combining principal component analysis method to study the soil microbial quantity, distribution of flora, community structure characteristics under dry and water farming as two different cultivated land use types. The PLFA analysis results showed that: under dry farming, total PLFA quantity ranged 8.35-25.15 nmol x g(-1), showed rape > broad bean > corn > rice > wheat, rape and broad bean significantly increased total PLFA quantity by 1.18 and 1.08 times compared to the treatment without straw; PLFA quantity of bacterial flora in treatments with straws was higher than that without straw, and fungal biomass was significantly increased, so was the species richness of microbial community. Under water faming, the treatments of different straws returning with landfill have improved the PLFA quantity of total soil microbial and flora comparing with the treatment without straw, fungi significantly increased, and species richness of microbial communities value also increased significantly. Total PLFA quantity ranged 4.04-22.19 nmol x g(-1), showed rice > corn > wheat > broad bean > rape, which in rape and broad bean treatments were lower than the treatment without straw; fungal PLFA amount in 5 kinds of straw except broad bean treatment was significantly higher than that of the treatment without straw, bacteria and total PLFA quantity in broad bean processing were significantly lower than those of other treatments, actinomycetes, G+, G- had no significant difference between all treatments; rice, wheat, corn, rape could significantly increase the soil microbial species richness index and dominance index under water faming. The results of principal component analysis showed that broad bean green stalk had the greatest impact on the microbial community structure in the dry soil, rape green stalk and wheat straw had the biggest influence on soil microbial community structure in water soil. PMID:26911016

  9. The role of snow cover affecting boreal-arctic soil freeze-thaw and carbon dynamics

    NASA Astrophysics Data System (ADS)

    Yi, Y.; Kimball, J. S.; Rawlins, M. A.; Moghaddam, M.; Euskirchen, E. S.

    2015-10-01

    Northern Hemisphere permafrost affected land areas contain about twice as much carbon as the global atmosphere. This vast carbon pool is vulnerable to accelerated losses through mobilization and decomposition under projected global warming. Satellite data records spanning the past 3 decades indicate widespread reductions (~ 0.8-1.3 days decade-1) in the mean annual snow cover extent and frozen-season duration across the pan-Arctic domain, coincident with regional climate warming trends. How the soil carbon pool responds to these changes will have a large impact on regional and global climate. Here, we developed a coupled terrestrial carbon and hydrology model framework with a detailed 1-D soil heat transfer representation to investigate the sensitivity of soil organic carbon stocks and soil decomposition to climate warming and changes in snow cover conditions in the pan-Arctic region over the past 3 decades (1982-2010). Our results indicate widespread soil active layer deepening across the pan-Arctic, with a mean decadal trend of 6.6 ± 12.0 (SD) cm, corresponding to widespread warming. Warming promotes vegetation growth and soil heterotrophic respiration particularly within surface soil layers (≤ 0.2 m). The model simulations also show that seasonal snow cover has a large impact on soil temperatures, whereby increases in snow cover promote deeper (≥ 0.5 m) soil layer warming and soil respiration, while inhibiting soil decomposition from surface (≤ 0.2 m) soil layers, especially in colder climate zones (mean annual T ≤ -10 °C). Our results demonstrate the important control of snow cover on northern soil freeze-thaw and soil carbon decomposition processes and the necessity of considering both warming and a change in precipitation and snow cover regimes in characterizing permafrost soil carbon dynamics.

  10. Soil response to corn residue removal and cover crops in Eastern South Dakota

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Removal of crop residue has been shown to degrade soil organic carbon (SOC), and hence soil quality. The present study was conducted to assess the impacts of corn (Zea mays L.) residue removal and cover crops on various soil quality parameters. The experimental site was located in Brookings County, ...

  11. Effects of soil composition and mineralogy on remote sensing of crop residue cover

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The management of crop residues in agricultural fields influences soil erosion and soil carbon sequestration. Remote sensing methods can efficiently assess crop residue cover and tillaje intensity over many fields in a region. Although the reflectance spectra of soils and crop residues are often s...

  12. Evaluation of Spectral Indices for Estimating Crop Residue Cover and Soil Carbon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long term use of conservation tillage practices can lead to increased soil organic carbon (SOC) compared to intensively tilled soils. However, monitoring soil tillage intensity over large areas for assessing changes in SOC is difficult. Remote sensing can potentially estimate crop residue cover, a...

  13. SOIL PHYSICAL AND BIOLOGICAL RESPONSES TO CATTLE GRAZING OF COVER CROPS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Integration of crops and livestock could be either detrimental or beneficial to soil properties, depending upon timing and intensity of animal traffic and residue cover of the soil surface. We determined surface-soil properties of a Typic Kanhapludult in northeastern Georgia USA during the first thr...

  14. Accounting for green vegetation and soil spectral properties to improve remote sensing of crop residue cover

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conservation tillage methods are beneficial as they disturb soil less and leaves increased crop residue cover (CRC) after planting on the soil surface. CRC helps reduce soil erosion, evaporation, and the need for tillage operations in fields. Greenhouse gas emissions are reduced to due to less fos...

  15. TILLAGE, COVER CROPS, AND NITROGEN FERTILIZATION EFFECTS ON SOIL NITROGEN AND COTTON AND SORGHUM YIELDS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sustainable soil and crop management practices that reduce soil erosion and nitrogen (N) leaching, conserve soil organic matter, and optimize cotton and sorghum yields still remain a challenge. We examined the influence of three tillage practices (no-till, strip till, and chisel till ), four cover c...

  16. Factors affecting water balance and percolate production for a landfill in operation.

    PubMed

    Poulsen, Tjalfe G; Moldrup, Per

    2005-02-01

    Percolate production and precipitation data for a full-scale landfill in operation measured over a 13-year period were used to evaluate the impact and importance of the hydrological conditions of landfill sections on the percolate production rates. Both active (open) and closed landfill sections were included in the evaluation. A simple top cover model requiring a minimum of input data was used to simulate the percolate production as a function of precipitation and landfill section hydrology. The results showed that changes over time in the hydrology of individual landfill sections (such as section closure or plantation of trees on top of closed sections) can change total landfill percolate production by more than 100%; thus, percolate production at an active landfill can be very different from percolate production at the same landfill after closure. Furthermore, plantation of willow on top of closed sections can increase the evapotranspiration rate thereby reducing percolate production rates by up to 47% compared to a grass cover. This process, however, depends upon the availability of water in the top layer, and so the evaporation rate will be less than optimal during the summer where soil-water contents in the top cover are low. PMID:15751398

  17. Magnetic Properties of Soils from Sarimukti Landfill as Proxy Indicators of Pollution (Case Study: Desa Sarimukti, Kabupaten Bandung Barat)

    NASA Astrophysics Data System (ADS)

    Cita Novala, Gesti; Fitriani, Dini; Susanto, Kusnahadi; Hajar Kirana, Kartika

    2016-01-01

    Leachate is the liquid arises from waste disposal. It contains heavy metals and magnetic minerals. Leachate could penetrate into sub surface that cause soil contamination. We have studied magnetic properties of soils from three zones in the Sarimukti landfill. We measured magnetic susceptibility in dual frequency and temperature dependent of susceptibility. The results showed that magnetic susceptibility at low frequency (xlf) of soil samples have the value ranging from 50-1400 (x 10-8 m3/kg). It infers that the samples were dominated by ferrimagnetic minerals. The relative difference of magnetic susceptibility measured at two frequency (xfd(%)) are less than 4%. It indicates that magnetic minerals probably derived from anthropogenic sources. There is negative correlation between xlf and Xfd(%). It supports the analysis that the source of magnetic minerals is anthropogenic. The results of the temperature dependent magnetic susceptibility measurements showed that the peak of magnetic susceptibility in heating curve occurs at the temperature about 200°C and 500°C. After 500°C, heating curve rapidly decreases. It can be inferred that the dominant type of magnetic minerals in the samples is titanomagnetite.

  18. Ammonia volatilization, N(2)O and CO(2) emissions from landfill leachate-irrigated soils.

    PubMed

    Zhang, Hou-Hu; He, Pin-Jing; Shao, Li-Ming

    2010-01-01

    Effects of leachate addition on ammonia volatilization and N(2)O and CO(2) emissions from two different soils were investigated using the 10-day laboratory incubation method at two levels of moisture content. Ammonia volatilization was dominated by soil pH and only occurred in alkaline clay soil, where 0.26-0.32% of soil ammonia could be lost. The N(2)O emission from the alkaline clay soil was one order of magnitude greater than that from the acidic sandy soil, when either water or leachate was irrigated. Increasing the moisture content from 46% water-filled pore space (WFPS) to 70% WFPS in the alkaline clay soil or the acidic sandy soil by either water or leachate irrigation increased the N(2)O emission by over twofold. The CO(2) emission from each soil sample at the two WFPSs was almost the same. The CO(2) emission from the alkaline clay soil with leachate addition was 72% lower than that from the acidic sandy soil with leachate addition, and 6.7 times higher than that from the alkaline clay soil with distilled water addition. Ammonia volatilization and N(2)O emission under leachate irrigation could be minimized by avoiding the excessively wet condition and by selecting the acidic sandy soil with low organic carbon and total nitrogen content. PMID:19773152

  19. Evidence for an underground runoff and soil permeability at the Ouled Fayet (Algiers, Algeria) buried waste pilot project: needs for a specific landfill implantation code

    NASA Astrophysics Data System (ADS)

    Djadia, Leila; Abtout, Abdslam; Boudella, Amar

    2014-05-01

    Results from geophysical investigations (electrical resistivity, electromagnetic mapping and seismic refraction) on an empty excavated rack of the Ouled Fayet (Algiers, Algeria) pilot landfill evidenced a more permeable soil than found by a feasibility study and the presence of an underground runoff underneath the rack. The problem was to evaluate the degree of confidence of the feasibility study, based on 76 10-m drilling cores only, 6 of them performed on the studied rack. To the contrary of what is claimed in the feasibility study a threat of lixiviate pollution is real. It is more than urgent to elaborate a code for landfill implantation in Algeria, which should include mandatory geophysical prospecting and deeper drilling cores. Keywords: Landfill, Geophysical prospecting, Underground runoff, Permeability, Algeria.

  20. Landfill mining: A critical review of two decades of research

    SciTech Connect

    Krook, Joakim; Svensson, Niclas; Eklund, Mats

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer We analyze two decades of landfill mining research regarding trends and topics. Black-Right-Pointing-Pointer So far landfill mining has mainly been used to solve waste management issues. Black-Right-Pointing-Pointer A new perspective on landfills as resource reservoirs is emerging. Black-Right-Pointing-Pointer The potential of resource extraction from landfills is significant. Black-Right-Pointing-Pointer We outline several key challenges for realization of resource extraction from landfills. - Abstract: Landfills have historically been seen as the ultimate solution for storing waste at minimum cost. It is now a well-known fact that such deposits have related implications such as long-term methane emissions, local pollution concerns, settling issues and limitations on urban development. Landfill mining has been suggested as a strategy to address such problems, and in principle means the excavation, processing, treatment and/or recycling of deposited materials. This study involves a literature review on landfill mining covering a meta-analysis of the main trends, objectives, topics and findings in 39 research papers published during the period 1988-2008. The results show that, so far, landfill mining has primarily been seen as a way to solve traditional management issues related to landfills such as lack of landfill space and local pollution concerns. Although most initiatives have involved some recovery of deposited resources, mainly cover soil and in some cases waste fuel, recycling efforts have often been largely secondary. Typically, simple soil excavation and screening equipment have therefore been applied, often demonstrating moderate performance in obtaining marketable recyclables. Several worldwide changes and recent research findings indicate the emergence of a new perspective on landfills as reservoirs for resource extraction. Although the potential of this approach appears significant, it is argued that facilitating implementation involves a number of research challenges in terms of technology innovation, clarifying the conditions for realization and developing standardized frameworks for evaluating economic and environmental performance from a systems perspective. In order to address these challenges, a combination of applied and theoretical research is required.

  1. The influence of atmospheric pressure on landfill methane emissions.

    PubMed

    Czepiel, P M; Shorter, J H; Mosher, B; Allwine, E; McManus, J B; Harriss, R C; Kolb, C E; Lamb, B K

    2003-01-01

    Landfills are the largest source of anthropogenic methane (CH4) emissions to the atmosphere in the United States. However, few measurements of whole landfill CH4 emissions have been reported. Here, we present the results of a multi-season study of whole landfill CH4 emissions using atmospheric tracer methods at the Nashua, New Hampshire Municipal landfill in the northeastern United States. The measurement data include 12 individual emission tests, each test consisting of 5-8 plume measurements. Measured emissions were negatively correlated with surface atmospheric pressure and ranged from 7.3 to 26.5 m3 CH4 min(-1). A simple regression model of our results was used to calculate an annual emission rate of 8.4 x 10(6) m3 CH4 year(-1). These data, along with CH4 oxidation estimates based on emitted landfill gas isotopic characteristics and gas collection data, were used to estimate annual CH4 generation at this landfill. A reported gas collection rate of 7.1 x 10(6) m3 CH4 year(-1) and an estimated annual rate of CH4 oxidation by cover soils of 1.2 x 10(6) m3 CH4 year(-1) resulted in a calculated annual CH4 generation rate of 16.7 x 10(6) m3 CH4 year(-1). These results underscore the necessity of understanding a landfill's dynamic environment before assessing long-term emissions potential. PMID:12957154

  2. Changes occurring to minimally disturbed soil and to plant covers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During the transition to organic production certain materials and practices, as described under US law, can not be used. During the transition period growers may, or may not, disturb the soil. There is little known about changes that occur if the soil is minimally disturbed during the transition t...

  3. Final closure cover for a Hanford radioactive mixed waste disposal facility

    SciTech Connect

    Johnson, K.D.

    1996-02-06

    This study provides a preliminary design for a RCRA mixed waste landfill final closure cover. The cover design was developed by a senior class design team from Seattle University. The design incorporates a layered design of indigenous soils and geosynthetics in a layered system to meet final closure cover requirements for a landfill as imposed by the Washington Administrative Code WAC-173-303 implementation of the Resource Conservation and Recovery Act.

  4. COVER CROP EFFECTS ON THE FATE OF SWINE MANURE-N APPLIED TO SOIL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cereal grain cover crops increase surface cover, anchor corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] residues, increase infiltration, reduce both rill and interrill erosion, scavenge excess nutrients from the soil, and are easily obtained and inexpensive compared to other cover crop optio...

  5. Hydraulic conductivity study of compacted clay soils used as landfill liners for an acidic waste.

    PubMed

    Hamdi, Noureddine; Srasra, Ezzeddine

    2013-01-01

    Three natural clayey soils from Tunisia were studied to assess their suitability for use as a liner for an acid waste disposal site. An investigation of the effect of the mineral composition and mechanical compaction on the hydraulic conductivity and fluoride and phosphate removal of three different soils is presented. The hydraulic conductivity of these three natural soils are 8.5 × 10(-10), 2.08 × 10(-9) and 6.8 × 10(-10)m/s for soil-1, soil-2 and soil-3, respectively. Soil specimens were compacted under various compaction strains in order to obtain three wet densities (1850, 1950 and 2050 kg/m(3)). In this condition, the hydraulic conductivity (k) was reduced with increasing density of sample for all soils. The test results of hydraulic conductivity at long-term (>200 days) using acidic waste solution (pH=2.7, charged with fluoride and phosphate ions) shows a decrease in k with time only for natural soil-1 and soil-2. However, the specimens of soil-2 compressed to the two highest densities (1950 and 2050 kg/m(3)) are cracked after 60 and 20 days, respectively, of hydraulic conductivity testing. This damage is the result of a continued increase in the internal stress due to the swelling and to the effect of aggressive wastewater. The analysis of anions shows that the retention of fluoride is higher compared to phosphate and soil-1 has the highest sorption capacity. PMID:22980909

  6. Landfill CH sub 4 : Rates, fates, and role in global carbon cycle

    SciTech Connect

    Bogner, J.; Spokas, K.

    1991-01-01

    Published estimates for worldwide landfill methane emissions range from 9 to 70 Tg yr{sup {minus}1}. Field and laboratory studies suggest that maximum methane yields from lanfilled refuse are about 0.06 to 0.09 m{sup 3} (dry Kg){sup {minus}1} refuse, depending on moisture content and other variables, such as organic loading, buffering capacity, and nutrients in landfill microevnironments. Methane yields may vary by more than an order of magnitude within a given site. Fates for landfill methane include (1) direct or delayed emission to the atmosphere through landfill cover materials or surface soils; (2) oxidation by methanotrophs in cover soils, with resulting emission of carbon dioxide; or (3) recovery of methane followed by combustion to produce carbon dioxide. The percent methane assigned to each pathway will vary among field sites and, for individual sites, through time. Nevertheless, a general framework for a landfill methane balance can be developed by consideration of landfill age, engineering and management practices, cover soil characteristics, and water balance. Direct measurements of landfill methane emissions are sparse, with rates between 10{sup {minus}6} and 10{sup {minus}8} g cm{sup {minus}2} s{sup {minus}1}; very high rates of 400 kg m{sup {minus}2} yr{sup {minus}1} have been measured at a semiarid unvegetated site. The proportion of landfill carbon that is ultimately converted to methane and carbon dioxide is problematical; the literature suggests that, at best, 25% to 40% of refuse carbon can be converted to biogas carbon. Cellulose contributes the major portion of the methane potential. Routine excavation of nondecomposed cellulosic materials after one or two decades of landfill burial suggests that uniformly high conversion rates are rarely attained at field sites.

  7. Landfill CH{sub 4}: Rates, fates, and role in global carbon cycle

    SciTech Connect

    Bogner, J.; Spokas, K.

    1991-12-31

    Published estimates for worldwide landfill methane emissions range from 9 to 70 Tg yr{sup {minus}1}. Field and laboratory studies suggest that maximum methane yields from lanfilled refuse are about 0.06 to 0.09 m{sup 3} (dry Kg){sup {minus}1} refuse, depending on moisture content and other variables, such as organic loading, buffering capacity, and nutrients in landfill microevnironments. Methane yields may vary by more than an order of magnitude within a given site. Fates for landfill methane include (1) direct or delayed emission to the atmosphere through landfill cover materials or surface soils; (2) oxidation by methanotrophs in cover soils, with resulting emission of carbon dioxide; or (3) recovery of methane followed by combustion to produce carbon dioxide. The percent methane assigned to each pathway will vary among field sites and, for individual sites, through time. Nevertheless, a general framework for a landfill methane balance can be developed by consideration of landfill age, engineering and management practices, cover soil characteristics, and water balance. Direct measurements of landfill methane emissions are sparse, with rates between 10{sup {minus}6} and 10{sup {minus}8} g cm{sup {minus}2} s{sup {minus}1}; very high rates of 400 kg m{sup {minus}2} yr{sup {minus}1} have been measured at a semiarid unvegetated site. The proportion of landfill carbon that is ultimately converted to methane and carbon dioxide is problematical; the literature suggests that, at best, 25% to 40% of refuse carbon can be converted to biogas carbon. Cellulose contributes the major portion of the methane potential. Routine excavation of nondecomposed cellulosic materials after one or two decades of landfill burial suggests that uniformly high conversion rates are rarely attained at field sites.

  8. Mitigating methane emissions and air intrusion in heterogeneous landfills with a high permeability layer.

    PubMed

    Jung, Yoojin; Imhoff, Paul T; Augenstein, Don; Yazdani, Ramin

    2011-05-01

    Spatially variable refuse gas permeability and landfill gas (LFG) generation rate, cracking of the soil cover, and reduced refuse gas permeability because of liquid addition can all affect CH(4) collection efficiency when intermediate landfill covers are installed. A new gas collection system that includes a near-surface high permeability layer beneath the landfill cover was evaluated for enhancing capture of LFG and mitigating CH(4) emissions. Simulations of gas transport in two-dimensional domains demonstrated that the permeable layer reduces CH(4) emissions up to a factor of 2 for particular spatially variable gas permeability fields. When individual macrocracks formed in the cover soil and the permeable layer was absent, CH(4) emissions increased to as much as 24% of the total CH(4) generated, double the emissions when the permeable layer was installed. CH(4) oxidation in the cover soil was also much more uniform when the permeable layer was present: local percentages of CH(4) oxidized varied between 94% and 100% across the soil cover with the permeable layer, but ranged from 10% to 100% without this layer for some test cases. However, the permeable layer had a minor effect on CH(4) emissions and CH(4) oxidation in the cover soil when the ratio of the gas permeability of the cover soil to the mean refuse gas permeability ? 0.05. The modeling approach employed in this study may be used to assess the utility of other LFG collection systems and management practices. PMID:20880688

  9. Methanotroph diversity in landfill soil: Isolation of novel type I and type II methanotrophs whose presence was suggested by culture-independent 16S ribosomal DNA analysis

    SciTech Connect

    Wise, M.G.; McArthur, J.V.; Smimkets, L.J.

    1999-11-01

    The diversity of the methanotrophic community in mildly acidic landfill cover soil was assessed by three methods: two culture-independent molecular approaches and a traditional culture-based approach. For the first of the molecular studies, two primer pairs specific for the 16S rRNA gene of validly published type I (including for former type X) and type II methanotrophs were identified and tested. These primers were used to amplify directly extracted soil DNA, and the products were used to construct type I and type II clone libraries. The second molecular approach, based on denaturing gradient gel electrophoresis (DGGE), provided profiles of the methanotrophic community members as distinguished by sequence differences in variable region 3 of the 16S ribosomal DNA. For the culturing studies, an extinction-dilution technique was employed to isolate slow-growing but numerically dominant strains. The key variables of the series of enrichment conditions were initial pH (4.8 versus 6.8), air/CH{sub 4}/CO{sub 2} headspace ratio (50:45:5 versus 90:9:1), and concentration of the medium (1x nitrate minimal salts [NMS] versus 0.2x NMS). Screening of the isolates showed that the nutrient-rich 1x NMS selected for type I methanotrophs, which the nutrient-poor 0.2x NMS tended to enrich for type II methanotrophs. Partial sequencing of the 16S rRNA gene from selected clones and isolates revealed some of the same novel sequence types.

  10. Cover crops and crop residue management under no-till systems improve soils and environmental quality

    NASA Astrophysics Data System (ADS)

    Kumar, Sandeep; Wegner, Brianna; Vahyala, Ibrahim; Osborne, Shannon; Schumacher, Thomas; Lehman, Michael

    2015-04-01

    Crop residue harvest is a common practice in the Midwestern USA for the ethanol production. However, excessive removal of crop residues from the soil surface contributes to the degradation of important soil quality indicators such as soil organic carbon (SOC). Addition of a cover crop may help to mitigate these negative effects. The present study was set up to assess the impacts of corn (Zea mays L.) residue removal and cover crops on various soil quality indicators and surface greenhouse gas (GHG) fluxes. The study was being conducted on plots located at the North Central Agricultural Research Laboratory (NCARL) in Brookings, South Dakota, USA. Three plots of a corn and soybean (Glycine max (L.) Merr.) rotation under a no-till (NT) system are being monitored for soils and surface gas fluxes. Each plot has three residue removal (high residue removal, HRR; medium residue removal, MRR; and low residue removal, LRR) treatments and two cover crops (cover crops and no cover crops) treatments. Both corn and soybean are represented every year. Gas flux measurements were taken weekly using a closed static chamber method. Data show that residue removal significantly impacted soil quality indicators while more time was needed for an affect from cover crop treatments to be noticed. The LRR treatment resulted in higher SOC concentrations, increased aggregate stability, and increased microbial activity. The LRR treatment also increased soil organic matter (SOM) and particulate organic matter (POM) concentrations. Cover crops used in HRR (high corn residue removal) improved SOC (27 g kg-1) by 6% compared to that without cover crops (25.4 g kg-1). Cover crops significantly impacted POM concentration directly after the residue removal treatments were applied in 2012. CO2 fluxes were observed to increase as temperature increased, while N2O fluxes increased as soil moisture increased. CH4 fluxes were responsive to both increases in temperature and moisture. On average, soils under cover crop management had lower N2O fluxes than soils that did not have a cover crop. Results from this study concluded that it is important to allow crop residues to return to the soil as they help to improve soil quality indicators. The presence of cover crops also will contribute to the improvement of these indicators once established and may help mitigate greenhouse gas emissions.

  11. Greenland soil bacteria & biogeochemistry: a vegetation cover proxy for climate warming effects

    NASA Astrophysics Data System (ADS)

    Dowdy, K. L.; Sistla, S.; Buckeridge, K. M.; Schimel, J.; Schaeffer, S. M.

    2013-12-01

    Climate warming in the high Arctic is expected to increase plant biomass, deepen thaw, and stimulate decomposition of soil organic matter. However, it remains unclear how warming, plant growth, and microbial processing will interact to drive Arctic carbon and nutrient cycling. For example, greater plant growth should increase carbon storage in the ecosystem; however, increasing plant C inputs and thawing permafrost carbon should stimulate microbial biomass, potentially causing soil respiration to outpace storage. Alternatively, greater plant cover may lower soil temperature through shading, potentially curtailing the predicted increase in microbial activity. To evaluate microbial responses to climate warming in the high Arctic, we characterized the soil bacterial community and related soil biogeochemical properties, including pH, temperature, moisture, bulk density, extractable nutrient pools, extractable organic carbon and nitrogen, and total microbial biomass along a vegetation cover gradient in northwest Greenland. Vegetation cover was classified using the Normalized Difference Vegetation Index (NDVI), and vegetation cover classes were used as a proxy for changes associated with warming. We found that soil moisture increased and soil temperature decreased significantly with vegetation cover; moisture and temperature were higher in organic than in mineral horizons. Extractable nutrients (NO3-, NH4+, PO43-) and extractable organic C and N generally increased with vegetation cover and are higher in organic than in mineral horizons within a given vegetation class, with the exception of NO3-, which was comparable between horizons. Despite increases in available carbon and nutrients, microbial biomass carbon in both horizons ultimately decreased with vegetation cover, as did microbial biomass nitrogen in the mineral horizon. Moreover, the relative proportion of microbial biomass carbon to extractable organic carbon decreased with vegetation cover, indicating that decomposers in more vegetated soils do not readily use available carbon. Our results suggest that despite an increase in available substrate in high vegetation cover soils, the insulating properties of vegetation ultimately limit decomposer activity. We hypothesize that as plant cover in the high Arctic increases with climate warming, nutrient mineralization - initially heightened by higher temperatures - will ultimately be curtailed by the insulating properties of vegetation, leading to decreased nutrient availability to plants and a decline in plant cover until soils warm and dry to reach conditions more optimal for microbial processing. Following oscillations between higher and lower vegetation cover, soils may ultimately return to a 'baseline' moderate vegetation cover.

  12. Landfill Methane

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Landfill methane (CH4) accounts for approximately 1.3% (0.6 Gt) of global anthropogenic greenhouse gas emissions relative to total emissions from all sectors of about 49 Gt CO2-eq yr-1. For countries with a history of controlled landfilling, landfills can be one of the larger national sources of ant...

  13. Contaminant transport in the sub-surface soil of an uncontrolled landfill site in China: site investigation and two-dimensional numerical analysis.

    PubMed

    Xie, Haijian; Chen, Yunmin; Thomas, Hywel R; Sedighi, Majid; Masum, Shakil A; Ran, Qihua

    2016-02-01

    A field investigation of contaminant transport beneath and around an uncontrolled landfill site in Huainan in China is presented in this paper. The research aimed at studying the migration of some chemicals present in the landfill leachate into the surrounding clayey soils after 17 years of landfill operation. The concentrations of chloride and sodium ions in the pore water of soil samples collected at depths up to 15 m were obtained through an extensive site investigation. The contents of organic matter in the soil samples were also determined. A two-dimensional numerical study of the reactive transport of sodium and chloride ion in the soil strata beneath and outside the landfill is also presented. The numerical modelling approach adopted is based on finite element/finite difference techniques. The domain size of approximately 300 × 30 m has been analysed and major chemical transport parameters/mechanisms are established via a series of calibration exercises. Numerical simulations were then performed to predict the long-term behaviour of the landfill in relation to the chemicals studied. The lateral migration distance of the chloride ions was more than 40 m which indicates that the advection and mechanical dispersion are the dominant mechanism controlling the contaminant transport at this site. The results obtained from the analysis of chloride and sodium migration also indicated a non-uniform advective flow regime of ions with depth, which were localised in the first few metres of the soil beneath the disposal site. The results of long-term simulations of contaminant transport indicated that the concentrations of ions can be 10 to 30 times larger than that related to the allowable limit of concentration values. The results of this study may be of application and interest in the assessment of potential groundwater and soil contamination at this site with a late Pleistocene clayey soil. The obtained transport properties of the soils and the contaminant transport mechanisms can also be used for the design of engineered barriers for the control of the long-term pollution of the site. PMID:26429140

  14. Heavy metals, salts and organic residues in old solid urban waste landfills and surface waters in their discharge areas: determinants for restoring their impact.

    PubMed

    Pastor, J; Hernández, A J

    2012-03-01

    This study was designed to determine the state of polluted soils in the main landfills of the Community of Madrid (central Spain), as part of a continuous assessment of the impacts of urban solid waste (USW) landfills that were capped with a layer of soil 20 years ago. Our analysis of this problem has been highly conditioned by the constant re-use of many of the USW landfills, since they have never been the target of any specific restoration plan. Our periodical analysis of cover soils and soils from discharge areas of the landfills indicates soil pollution has worsened over the years. Here, we examined heavy metal, salts, and organic compounds in soil and surface water samples taken from 15 landfills in the Madrid region. Impacts of the landfill soil covers on nematode and plant diversity were also evaluated. These analyses continue to reveal the presence of heavy metals (Zn, Cu, Cr, Ni, Pb, Cd) in soils, and salts (sulphates, chlorides and nitrates) in soils and surface waters. In addition, non-agricultural organic compounds, mainly aromatic and aliphatic hydrocarbons, often appeared in very high concentrations, and high levels of insecticides such as gamma-HCH (lindane) were also detected in soils. Around 50% of the water samples collected showed chemical demand of oxygen (CDO) values in excess of 150 mg/l. Traces of phenolic compounds were detected in some landfills, some of which exhibited high levels of 2-chlorophenol and pentachlorophenol. All these factors are conditioning both the revegetation of the landfill systems and the remediation of their slopes and terrestrial ecosystems arising in their discharge areas. This work updates the current situation and discusses risks for the health of the ecosystems, humans, domestic animals and wildlife living close to these landfills. PMID:21764209

  15. Hydraulic conductivity study of compacted clay soils used as landfill liners for an acidic waste

    SciTech Connect

    Hamdi, Noureddine; Srasra, Ezzeddine

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Examined the hydraulic conductivity evolution as function of dry density of Tunisian clay soil. Black-Right-Pointing-Pointer Follow the hydraulic conductivity evolution at long-term of three clay materials using the waste solution (pH=2.7). Black-Right-Pointing-Pointer Determined how compaction affects the hydraulic conductivity of clay soils. Black-Right-Pointing-Pointer Analyzed the concentration of F and P and examined the retention of each soil. - Abstract: Three natural clayey soils from Tunisia were studied to assess their suitability for use as a liner for an acid waste disposal site. An investigation of the effect of the mineral composition and mechanical compaction on the hydraulic conductivity and fluoride and phosphate removal of three different soils is presented. The hydraulic conductivity of these three natural soils are 8.5 Multiplication-Sign 10{sup -10}, 2.08 Multiplication-Sign 10{sup -9} and 6.8 Multiplication-Sign 10{sup -10} m/s for soil-1, soil-2 and soil-3, respectively. Soil specimens were compacted under various compaction strains in order to obtain three wet densities (1850, 1950 and 2050 kg/m{sup 3}). In this condition, the hydraulic conductivity (k) was reduced with increasing density of sample for all soils. The test results of hydraulic conductivity at long-term (>200 days) using acidic waste solution (pH = 2.7, charged with fluoride and phosphate ions) shows a decrease in k with time only for natural soil-1 and soil-2. However, the specimens of soil-2 compressed to the two highest densities (1950 and 2050 kg/m{sup 3}) are cracked after 60 and 20 days, respectively, of hydraulic conductivity testing. This damage is the result of a continued increase in the internal stress due to the swelling and to the effect of aggressive wastewater. The analysis of anions shows that the retention of fluoride is higher compared to phosphate and soil-1 has the highest sorption capacity.

  16. Fluxes of methane between landfills and the atmosphere: Natural and engineered controls

    SciTech Connect

    Bogner, J.; Meadows, M.; Czepiel, P.

    1997-08-01

    Field measurement of landfill methane emissions indicates natural variability spanning more than 2 seven orders of magnitude, from approximately 0.0004 to more than 4000 g m{sub -2} day{sup -1}. This wide range reflects net emissions resulting from production (methanogenesis), consumption (methanotrophic oxidation), and gaseous transport processes. The determination of an {open_quotes}average{close_quotes} emission rate for a given field site requires sampling designs and statistical techniques which consider spatial and temporal variability. Moreover, particularly at sites with pumped gas recovery systems, it is possible for methanotrophic microorganisms in aerated cover soils to oxidize all of the methane from landfill sources below and, additionally, to oxidize methane diffusing into cover soils from atmospheric sources above. In such cases, a reversed soil gas concentration gradient is observed in shallow cover soils, indicating bidirectional diffusional transport to the depth of optimum methane oxidation. Rates of landfill methane oxidation from field and laboratory incubation studies range up to 166 g m{sup -2} day{sup -1} among the highest for any natural setting, providing an effective natural control on net emissions. Estimates of worldwide landfill methane emissions to the atmosphere have ranged from 9 to 70 Tg yr{sup -1}, differing mainly in assumed methane yields from estimated quantities of landfilled refuse. At highly controlled landfill sites in developed countries, landfill methane is often collected via vertical wells or horizontal collectors. Recovery of landfill methane through engineered systems can provide both environmental and energy benefits by mitigating subsurface migration, reducing surface emissions, and providing an alternative energy resource for industrial boiler use, on-site electrical generation, or upgrading to a substitute natural gas.

  17. Effects of recurrent rolling/crimping operations on cover crop termination, soil moisture, and soil strength for conservation organic systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rolling/crimping technology has been utilized to mechanically terminate cover crops in conservation agriculture. In the southeastern United States, to eliminate competition for valuable soil moisture, three weeks are typically required after rolling to plant a cash crop into the desiccated cover cro...

  18. Establishment of five cover crops and total soil nutrient extraction in a humid tropical soil in the Peruvian Amazon

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to evaluate the establishment of five cover crops and their potential to increase soil fertility through nutrient extraction, an experiment was installed in the Research Station of Choclino, San Martin, Peru. Five cover crops were planted: Arachis pintoi Krapov. & W.C. Greg, Calopogonium m...

  19. Capturing residual soil nitrogen with winter cereal cover crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The wide-spread drought during the 2012 summer has resulted in reduced crop growth, poor yields, and an anticipated increase in residual nitrate (NO3) nitrogen (N) in the soil profile. This residual N can potentially increase NO3-N losses to ground and/or surface waters, as well as increase carry-ov...

  20. SOIL AND VEGETATIVE COVERS FOR LEAD (PB) MINE WASTE PILES

    EPA Science Inventory

    Conduct vegetation studies that evaluate a variety of seed mixtures and surface amendments (soil, compost, biosolids, yard waste and fertilizers). US Bureau of Reclamation with experts formerly with US Bureau of Mines to contribute to Vegetation Plan for Big River NTCR EE/CA

  1. Modeling impact of small Kansas landfills on underlying aquifers

    USGS Publications Warehouse

    Sophocleous, M.; Stadnyk, N.G.; Stotts, M.

    1996-01-01

    Small landfills are exempt from compliance with Resource Conservation and Recovery Act Subtitle D standards for liner and leachate collection. We investigate the ramifications of this exemption under western Kansas semiarid environments and explore the conditions under which naturally occurring geologic settings provide sufficient protection against ground-water contamination. The methodology we employed was to run water budget simulations using the Hydrologic Evaluation of Landfill Performance (HELP) model, and fate and transport simulations using the Multimedia Exposure Assessment Model (MULTIMED) for several western Kansas small landfill scenarios in combination with extensive sensitivity analyses. We demonstrate that requiring landfill cover, leachate collection system (LCS), and compacted soil liner will reduce leachate production by 56%, whereas requiring only a cover without LCS and liner will reduce leachate by half as much. The most vulnerable small landfills are shown to be the ones with no vegetative cover underlain by both a relatively thin vadose zone and aquifer and which overlie an aquifer characterized by cool temperatures and low hydraulic gradients. The aquifer-related physical and chemical parameters proved to be more important than vadose zone and biodegradation parameters in controlling leachate concentrations at the point of compliance. ??ASCE.

  2. Subsurface investigation in Sarimukti landfill using DC resistivity

    NASA Astrophysics Data System (ADS)

    Kirana, Kartika Hajar; Susanto, Kusnahadi; Susilawati, Anggie

    2015-09-01

    Layering process in landfill will produce leachate that produced by the entry of a mixture of rain water or ground water into the piles solid waste. In Sarimukti landfill, leachate from landfill channeled through a pipe to the leachate pond that planted beneath the soil surface. If the pipe is leaking, the leachate will contaminate the surrounding soil and may also to contaminate groundwater. Therefore, it is necessary to investigate subsurface conditions. One type of subsurface investigation can be determined by measuring the resistivity by using DC resistivity method. Resistivity measured in Sarimukti landfill with semigriding design including 8 lines perpendicular to each other. The result show there is resistivity contrast of materials, such as the solid waste, soil, water content that is predicted as leachate, and methane gas. The range of resistivity values are from 1 Ωm to 500 Ωm with variations of depth in according to line lenght. The resistivity values respectively: leachate is 1 to 10 Ωm; Wet soil is 10 to 100 Ωm; wet waste is 100 to 400 Ωm; gas is > 400 Ωm. Then, leachate was found at depth of 25 meters and wet soil is predicted as aquifer layer with 70 meters depth. The resistivity of aquifer layer is 1 to 20 Ωm and covered by silt clay as clay cap. Thus, it can predicted that leachate not seep into the aquifer layer.

  3. VEGETATIVE COVERS FOR WASTE CONTAINMENT

    EPA Science Inventory

    Disposal of municipal ahd hazardous waste in the United States is primarily accomplished by containment in lined and capped landfills. Evapotranspiration cover systems offer an alternative to conventional landfill cap systems. These covers work on completely different principles ...

  4. Landfill mining: a critical review of two decades of research.

    PubMed

    Krook, Joakim; Svensson, Niclas; Eklund, Mats

    2012-03-01

    Landfills have historically been seen as the ultimate solution for storing waste at minimum cost. It is now a well-known fact that such deposits have related implications such as long-term methane emissions, local pollution concerns, settling issues and limitations on urban development. Landfill mining has been suggested as a strategy to address such problems, and in principle means the excavation, processing, treatment and/or recycling of deposited materials. This study involves a literature review on landfill mining covering a meta-analysis of the main trends, objectives, topics and findings in 39 research papers published during the period 1988-2008. The results show that, so far, landfill mining has primarily been seen as a way to solve traditional management issues related to landfills such as lack of landfill space and local pollution concerns. Although most initiatives have involved some recovery of deposited resources, mainly cover soil and in some cases waste fuel, recycling efforts have often been largely secondary. Typically, simple soil excavation and screening equipment have therefore been applied, often demonstrating moderate performance in obtaining marketable recyclables. Several worldwide changes and recent research findings indicate the emergence of a new perspective on landfills as reservoirs for resource extraction. Although the potential of this approach appears significant, it is argued that facilitating implementation involves a number of research challenges in terms of technology innovation, clarifying the conditions for realization and developing standardized frameworks for evaluating economic and environmental performance from a systems perspective. In order to address these challenges, a combination of applied and theoretical research is required. PMID:22083108

  5. Impact of cover crops and tillage on porosity of podzolic soil

    NASA Astrophysics Data System (ADS)

    Błażewicz-Woźniak, M.; Konopiñski, M.

    2013-09-01

    The aim of the study was to determine the influence of cover crops biomass, mixed with the soil on different dates and with the use of different tools in field conditions. The cover crop biomass had a beneficial influence on the total porosity of the 0-20 cm layer of the soil after winter. The highest porosity was achievedwith cover crops of buckwheat, phacelia and mustard, the lowest with rye. During the vegetation period the highest porosity of soil was observed in the ridges. Among the remaining non-ploughing cultivations, pre-winter use of stubble cultivator proved to have a beneficial influence on the soil porosity, providing results comparable to those achieved in conventional tillage. The differential porosity of the soil was modified not only by the catch crops and the cultivation methods applied, but also by the sample collection dates, and it did change during the vegetation period. The highest content of macropores after winter was observed for the phacelia cover crop, and the lowest in the case of cultivation without any cover crops. Pre-winter tillage with the use of a stubble cultivator increased the amount of macropores in soil in spring, and caused the biggest participation of mesopores as compared with other non-ploughing cultivation treatments of the soil. The smallest amount of mesopores was found in the ridges.

  6. Changes in soil properties and soil cover structure due to intensive erosion and accumulation processes in loess soils

    NASA Astrophysics Data System (ADS)

    Zadorova, Tereza; Penizek, Vit; Jaksik, Ondrej; Kodesova, Radka; Jirku, Veronika; Fer, Miroslav

    2010-05-01

    Intensive water and tillage erosion and consequent accumulation are the most important processes affecting the agroecosystems in loess regions and changing soil properties, e.g. organic carbon content, carbonate content or structure stability, and general distribution of soil units in the landscape. South Moravian loess belt, formerly covered mostly by Haplic Chernozem, is now formed by a highly diversified soil mosaic. At a morphologically heterogenous study plot (6 ha), a study on relationship between soil properties and terrain characteristics was held. DTM analysis, detailed terrain survey and laboratory analysis were the main methods adopted in the study. Three main soil units were identified: Haplic Chernozem, calcareous Regosol and Colluvial soil. The distribution of each soil unit correlates with different terrain attributes. Regosols are significatly connected to the steep slope, while their correlation with the curvature or hydrological indexes is lower. On the contrary, the Colluvial soils distribution depends mainly on values of curvature and topographical wetness index and is independent on the slope. Chernozem is related to a specific terrain position more than to any of the terrain attributes. Soil depth and humus horizon thickness vary extremelly - from 0.2 m at the erosionally exposed slopes to more than 2.5 m at the concave parts and the toeslope. Soil depth is significantly correlated with all of the tested terrain attributes except of the slope - the strongest correlation was proved in case of mean curvature, topographical wetness index and catchment area. Different degree of changes in particular soil properties results from the specificity of both erosion process and parent material character. Organic carbon content in the topsoil varies significantly. Humus is practically absent in the steepest parts of the slope where the loess is exposed. High amounts of Corg were identified in the undisturbed A horizons of the Chernozem unit. In the concave parts of the slope and at the toeslope, the Corg content in the plough layer is lower due to an admixture of non-humus material transported from the steep parts of the plot. Nevertheless, the deeper (0.7 - 2 m), buried parts of the colluvial profiles are very rich in organic carbon (up to 4 %). These horizons may represent fossil chernic horizons of former Chernozems, buried by intensive sedimentation of humic material. Similar variability was found in carbonate content values, always due to amount of loess admixture in the plough horizon. While the soil structure stability, depending strongly on humus content, was the highest in the Chernozem unit, in the eroded parts it was highly unstable. Changes in the cation exchange capacity and pH are less distinctive. CEC slightly increases in humus-rich soils and pH is higher in the eroded parts of the plot due to the loess exposition. Acknowledgement: Authors acknowledge the financial support of the Grant Agency of the Czech Republic (grant No. GA CR 526/08/0434) and the Ministry of Education, Youth and Sports of the Czech Republic (grant No. MSM 6046070901).

  7. Legume Cover Crops are More Beneficial than Natual Fallows in MInimally Tilled Ugandan Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is important to establish the various eff ects of legume cover crops on soil physicochemical properties because they have been considered for use as improved fallows (with shorter rest periods) to enhance development and maintenance of soil productivity. Our objectives were to assess: (i) abovegr...

  8. Winter Cover Crop Biomass for Biofuel Production, Implications for Soil Coverage and Profitability

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High residue winter cover crops are critical for maximizing conservation tillage system benefits, including reductions in soil erosion, improved soil productivity, higher crop yields and greater net returns from crop production. With the increasing demand for biofuel production, the potential to har...

  9. COVER CROP EFFECT ON SOIL CARBON FRACTIONS UNDER CONSERVATION TILLAGE COTTON

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cover crops may influence soil carbon (C) sequestration and microbial activities by providing additional residue C to soil. We examined the influence of legume [crimson clover (Trifolium incarnatum L.)], nonlegume [rye (Secaele cereale L.)], blend [a mixture of legumes containing balansa clover (Tri...

  10. Effects of cover cropping on soil and rhizosphere microbial community structure in tomato production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Black polyethylene film is frequently used in vegetable farming systems to promote rapid warming of the soil in spring, conserve soil moisture, and suppress weeds. Alternative systems have been developed using cover cropping with legumes to provide a weed-suppressive mulch while also fixing nitrogen...

  11. Improved Remote Crop Residue Cover Estimation by Incorporation of Soil and Residue Information

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Modern agricultural practices are increasingly making use of conservation (reduced- and no-till) methods, in order to minimize soil erosion and increase soil organic carbon (SOC) content. These methods result in increased crop residue cover after planting when compared to conventional tillage metho...

  12. Mapping crop Residue Cover and Soil Tillage Intensity Using Remote Sensing

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Until recently crop residues were managed primarily to reduce soil erosion and increase soil organic carbon, but demands for biofuels may remove much of the residue. Current methods of measuring crop residue cover are inadequate for characterizing the temporal and spatial variability of crop residu...

  13. Hyperspectral remote sensing estimation of crop residue cover: Soil mineralogy, surface conditions, and their effects

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conservation tillage practices can enhance soil organic carbon content (SOC), improve soil structure, and reduce erosion. However, direct assessment of tillage practice for monitoring SOC change over large regions is difficult. Remote sensing of crop residue cover (CRC) can help assess tillage pra...

  14. Soil and crop nitrogen as influenced by tillage, cover crops, and nitrogen fertilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil and crop management practices may influence soil mineral N, crop N uptake, and N leaching. We evaluated the effects of three tillage practices [no-till (NT), strip till (ST), and chisel till (CT)], four cover crops {legume [hairy vetch (Vicia villosa Roth)], nonlegume [rye (Secale cereale L.)],...

  15. Cover Crop and Manure Effects on Soil Properties in a Corn Silage System

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Continuous corn (Zea mays L.) silage production, even with no-tillage, can degrade soil quality because of nutrient depletion and minimal organic matter additions. Manure application and the use of different companion or cover crops in corn silage production systems may lessen or prevent soil qualit...

  16. Soil carbon and nitrogen affected by perennial grass, cover crop, and nitrogen fertilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil C and N sequestration and the potential for N leaching can be influenced by the type of perennial grass, cover crop, and N fertilization due to differences in crop yields and the amount of residue returned to the soil. We evaluated the effects of the combinations of perennial grasses (energy ca...

  17. Linking N Cycling to Microbial Function Within Soil Microenvironments in Cover Crop Systems

    NASA Astrophysics Data System (ADS)

    Kong, A. Y.; Scow, K. M.; Hristova, K.; Six, J.

    2007-12-01

    Cover crops have emerged as a crop management strategy to achieve agricultural sustainability and maintain environmental quality. Thus, fundamental knowledge of microbial-mediated C and N cycling is vital to understanding soil organic matter (SOM) dynamics in cover cropped agroecosystems. We investigated the effects of short-term cover crop-C input on N processing by microbial communities within SOM microenvironments and in bulk soil, across a gradient of organic to conventional crop management. We hypothesized that cover crop C and N inputs promote soil aggregation, which increases the abundance of ammonia oxidizing bacteria (AOB) and stimulates greater microbial cycling of N within soil microenvironments, thereby leading to potential increases in N stabilization coupled with decreases in N loss. Our hypothesis was tested on the long-term organic, low-input, and conventional maize-tomato rotations at the Center for Integrated Farming Systems experiment (Davis, CA). We collected soil samples (0-15cm) across the cover crop and subsequent maize growing seasons and then isolated three SOM fractions soil: coarse particulate organic matter (cPOM; >250um), microaggregates (53-250um), and silt-and-clay (<53um). Total C and N were measured on both bulk soil and SOM fractions. Real-time polymerase chain reaction (PCR) using primers for the functional genes, amoA and nosZ, were employed to quantify AOB and denitrifier population sizes, respectively. We also measured gross ammonification and nitrification rates in short-term 15N-incubations of the bulk soil to link cover crop induced N cycling to N-transforming bacteria. Total soil C and N concentrations and soil aggregation were higher in the organic than conventional and low-input systems. The amoA and no Z copy numbers g-1 dry soil were highest in the microaggregate fraction and similar between the cPOM and silt-and-clay fractions, among all cropping treatments. Abundances of AOB and denitrifiers were lower in bulk soil from the conventional and low- input than organic system. Our study indicates that long-term, annual cover crop inputs to the organic system lead to greater aggregation and development of microaggregate structures. Consequently, the abundance of nitrifiers and denitrifiers as well as the rates of ammonification and nitrification are augmented in the organic system compared to the conventional, which does not receive a cover crop, and the low-input system, which receives cover crops only in alternate years. These results shed light on the specific mechanisms governing short-term N stabilization versus losses under long-term crop management.

  18. Controls of biological soil crust cover and composition shift with succession in sagebrush shrub-steppe

    USGS Publications Warehouse

    Dettweiler-Robinson, E.; Bakker, J.D.; Grace, J.B.

    2013-01-01

    Successional stage may determine strength and causal direction of interactions among abiotic and biotic factors; e.g., species that facilitate the establishment of other species may later compete with them. We evaluated multivariate hypotheses about abiotic and biotic factors shaping biological soil crusts (BSCs) in early and late successional stages. We surveyed vegetation and BSC in the shrub-steppe ecosystem of the Columbia Basin. We analyzed the relationships with bryophyte and lichen covers using structural equation models, and analyzed the relationships with BSC composition using Indicator Species Analysis and distance-based linear models. Cover, indicator species, and composition varied with successional stage. Increasing elevation and bryophyte cover had higher lichen cover early in succession; these relationships were negative in the later successional stage. Lichen cover did not appear to impede B. tectorum cover, but B. tectorum appeared to strongly negatively affect lichen cover in both stages. Biological soil crust composition varied with bunchgrass cover in the early successional stage, but with elevation and B. tectorum cover later in succession. Our findings support the hypotheses that as succession progresses, the strength and direction of certain community interactions shift, and B. tectorum leads to reductions in biological soil crust cover regardless of successional stage.

  19. OUTER LOOP LANDFILL CASE STUDY

    EPA Science Inventory

    This presentation will describe the interim data reaulting from a CRADA between USEPA and Waste Management, Inc. at the outer Loop Landfill Bioreactor research project located in Louisville, KY. Recently updated data will be presented covering landfill solids, gas being collecte...

  20. Integrating choice of variety, soil amendments, and cover crops to optimize organic rice production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We have completed our first year of this project to determine the impact of winter cover crops, soil amendments, and rice varieties on organic rice production at Beaumont, TX. Two winter cover crops were established successfully and the amounts of dry biomass produced were 4,690 and 5,157 lb/acre f...

  1. Improved Remotely-Sensed Estimates of Crop Residue Cover by Incorporating Soils Information

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Remote sensing allows for the rapid determination of crop residue cover. The Cellulose Absorption Index (CAI) has been shown to more accurately estimate residue cover and non-photosynthetic vegetation than other indices. CAI is useful as values are linear areal mixtures of soil and residue spectra...

  2. CO2 evolution in highland soils of different land cover types in Iceland

    NASA Astrophysics Data System (ADS)

    Mankasingh, Utra; Gísladóttir, Guðrún; Þórsson, Jóhann; Palomaki, Minna

    2015-04-01

    Soil respiration is a key ecosystem process that releases carbon from soil as CO2. Soil CO2 emission is sensitive to temperature, moisture and disturbance and is influenced by land use and land cover change, especially in the upper soil organic layer. Release of CO2 from soils of the south Icelandic highlands (318 - 356 m above sea level) was studied to observe soil respiration in different land cover types and to quantify soil C lost as CO2. In a laboratory incubation study, exponential release of CO2 from soils was observed (>6 months) for the field moist soils collected from the highlands. Soils were collected at 12 sites from the land cover types (plant communities) in September 2013. The land cover types, categorized by plant communities, were: grasslands (G1-G8), with moss, Carex Bigelowii and dwarf shrubs; a sandy fluvial wetland (S), and unvegetated gravels (M1-M3). Since this experiment was conducted at 25° C whilst the observed annual average temperature was 1.5 ° C (Vatnsfell, 10 year average), this experiment presents an accelerated picture of CO2 released from soils over a much longer time period. For most soils, the rate of release decreased after 5 days. For all land cover types, the CO2 release was greatest in the topspoil and this decreased with depth. Soils with the highest % organic matter (G sites characterized by mosses and few vascular species) appear to release the most CO2. In the top 5 cm, the CO2 emissions follow the trend: grasslands (G1-G8)> sandy fluvial wetland (S) > unvegetated sites (M1-M3). This trend appears to be related to the amount of organic matter present. For all sites, the less than 250 mg CO2 was lost per kg of soil after 75 days, which is equivalent to losing less than 69 mg C per kg soil, and represented less than 0.5% of the total carbon present in any soil; less than 360 mg CO2 was lost after 260 days.

  3. Mercury air-borne emissions from 5 municipal solid waste landfills in Guiyang and Wuhan, China

    NASA Astrophysics Data System (ADS)

    Li, Z. G.; Feng, X.; Li, P.; Liang, L.; Tang, S. L.; Wang, S. F.; Fu, X. W.; Qiu, G. L.; Shang, L. H.

    2010-01-01

    A detailed study on atmospheric mercury emissions from municipal solid waste (MSW) landfills in China is necessary to understand mercury behavior in this source category, simply because China disposes of bulk MSW by landfilling and a large quantity of mercury enters into landfills. Between 2003 and 2006, mercury airborne emissions through different pathways, as well as mercury speciation in landfill gas (LFG) were measured at 5 MSW landfills in Guiyang and Wuhan, China. The results showed that mercury content in the substrate fundamentally affected the magnitude of mercury emissions, resulting in the highest emission rate (as high as 57 651 ng Hg m-2 h-1) at the working face and in un-covered waste areas, and the lowest measured at soil covers and vegetation areas (less than 20 ng Hg m-2 h-1). Meteorological parameters, especially solar radiation, influenced the diurnal pattern of mercury surface-air emissions. Total gaseous mercury (TGM) in LFG varied from 2.0 to 1406.0 ng m-3, monomethyl mercury (MMHg) and dimethyl mercury (DMHg) in LFG averaged at 1.93 and 9.21 ng m-3, and accounted for 0.51% and 1.79% of the TGM in the LFG, respectively. Total mercury emitted from the five landfills ranged from 17 to 3285 g yr-1, with the highest from the working face, then soil covering, and finally the vent pipes.

  4. The litter cover of citrus leaves control soil and water losses in chemically managed orchards

    NASA Astrophysics Data System (ADS)

    Cerdà, A.; Jurgensen, M. F.; González-Peñaloza, F. A.

    2012-04-01

    Soil erosion in chemically managed orchards results in bare soil due to the removal of the weeds and the lack of catch crops. Those conditions results in extremely high erosion rates in citrus orchards (Cerdà et al., 2011) such it has been found in other orchards in the Mediterranean where the soil degradation trigger a change in the soil water properties (Gómez et al., 1999). The Mediterranean climatic and human conditions contribute to very active soil water erosion (Ruiz Sinoga et al., 2010) where rilling and piping are found (Romero-Diaz, 2007). It is widely known that high erosion rates can trigger the soil degradation such it has been found in vineyards (Ramos and Martínez Casasnovas, 2006), Olive (García Orenes et al., 2010) and other crops, which is related to the land management and land use (García Ruiz, 2010). Within the chemically managed citrus orchards, the surface cover is usually bare due to the removal of the pruned branches (usually burned) and the use of herbicides every season. A thin and non-continuous litter layer of leaves from the citrus trees covers the soil surface, which sometimes are removed by the farmers to keep the soil clean. There is no information about the effect of the citrus leaves effects on soil and water losses. The objective of this paper is to quantify the effect of the leaves cover on the surface runoff and soil losses. Experiments were conducted by means of simulated rainfall at 55 mm h-1 during one hour in a small circular plot (0.25 m2) to quantify in the field the effect of different litter cover on soil erosion and water losses. An orchard of orange trees (Navel-lane-late, 10 year old, and planted at 6 x 5m with a 45 % cover) was selected in the Municipality of Montesa. Witin the 2 ha field 35 plots were selected with litter covers from 0 to 100 % cover. The runoff discharge was measured every minute and each 5 minutes a sample for runoff sediment concentration was collected. The sediment concentration was measured by dessication. All the measurements were conducted during the summer (August 2008). The results show that the litter cover control the erosion processes. The orange leaves lying on the floor can reduce the soil losses to negligible values when the cover is higher than 60 %. After 20 % of litter cover the soil losses are dramatically reduced to values lower than 50 % of the soil losses under bare soil conditions. The litter cover also reduces the runoff rates, but the reduction is in 50 % for 80 % litter cover. The 20 % litter cover results only in a small reduction in the runoff discharge. The research conducted demonstrate that the farmers should maintain the leaves on the floor (do not brush them as they use to do) to control the high erosion rates. This research study is being supported by the the research project CGL2008-02879/BTE

  5. Managing soil nitrate with cover crops and buffer strips in Sicilian vineyards

    NASA Astrophysics Data System (ADS)

    Novara, A.; Gristina, L.; Guaitoli, F.; Santoro, A.; Cerdà, A.

    2013-08-01

    When soil nitrate levels are low, plants suffer nitrogen (N) deficiency but when the levels are excessive, soil nitrates can pollute surface and subsurface waters. Strategies to reduce the nitrate pollution are necessary to reach a sustainable use of resources such as soil, water and plant. Buffer strips and cover crops can contribute to the management of soil nitrates, but little is known of their effectiveness in semiarid vineyards plantations. The research was carried out in the south coast of Sicily (Italy) to evaluate nitrate trends in a vineyard managed both conventionally and using two different cover crops (Triticum durum and Vicia sativa cover crop). A 10 m-wide buffer strip was seeded with Lolium perenne at the bottom of the vineyard. Soil nitrate was measured monthly and nitrate movement was monitored by application of a 15N tracer to a narrow strip between the bottom of vineyard and the buffer and non-buffer strips. Lolium perenne biomass yield in the buffer strips and its isotopic nitrogen content were monitored. Vicia sativa cover crop management contributed with an excess of nitrogen, and the soil management determined the nitrogen content at the buffer areas. A 6 m buffer strip reduced the nitrate by 42% with and by 46% with a 9 m buffer strip. Thanks to catch crops, farmers can manage the N content and its distribution into the soil over the year, can reduced fertilizer wastage and reduce N pollution of surface and groundwater.

  6. COMPACTED SOIL BARRIERS OF ABANDONED LANDFILL SITES ARE LIKELY TO FAIL IN THE LONG-TERM

    EPA Science Inventory

    Buried wastes are isolated from the environment by barriers constructed entirely or in part of compacted soil. he chief concern in barrier design has been to isolate the waste in the short term by preventing movement of water into and through the waste. owever, in the long term a...

  7. Characteristics of environmental factors and their effects on CH4 and CO2 emissions from a closed landfill: an ecological case study of Shanghai.

    PubMed

    Xiaoli, Chai; Ziyang, Lou; Shimaoka, Takayuki; Nakayama, Hirofumi; Ying, Zhu; Xiaoyan, Cao; Komiya, Teppei; Ishizaki, Toshio; Youcai, Zhao

    2010-03-01

    To elucidate the influence of landfill gas (LFG) emission on environmental factors, an ecological investigation that was primarily concerned with the characteristics of vegetation, cover soil, and solid waste in the landfill was carried out. Temporal and spatial variations in vegetation diversity and coverage and their effects on reducing the emission of methane in the landfill were investigated. The results showed that both vegetation coverage and diversity increased with elapsed landfill closure time. The transition trend of the vegetation species was from perennial plant (Phragmites australis) to annual plants. Perennial vegetation was the dominant type of vegetation during the early closure period, and annual vegetation coverage increased with closure time. Vegetation preferentially appeared in areas of comparatively high depth of cover soil, which was characterized by high moisture retentiveness that enabled vegetation growth. The concentrations of methane and carbon dioxide in the cover soil significantly decreased with increasing closure time. The concentrations of methane and carbon dioxide from bare cover soil were higher than those from vegetated cover soil whereas the CO(2) flux of bare cover soil was less than that of vegetated cover soil. PMID:19880303

  8. RESPONSE OF THE SOIL MICROBIAL COMMUNITY TO SOIL FUMIGATION AND MUSTARD COVER CROPS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil fumigants such as metam-sodium, used in potato production of the Columbia Basin of WA, are very effective for the control of soil borne pathogens, weeds, and nematodes that reduce crop yield and quality. Soil fumigation has been assumed to have minor impacts on the general soil microbial commun...

  9. Ground cover rice production system facilitates soil carbon and nitrogen stocks at regional scale

    NASA Astrophysics Data System (ADS)

    Liu, M.; Dannenmann, M.; Lin, S.; Saiz, G.; Yan, G.; Yao, Z.; Pelster, D.; Tao, H.; Sippel, S.; Tao, Y.; Zhang, Y.; Zheng, X.; Zuo, Q.; Butterbach-Bahl, K.

    2015-02-01

    Rice production is increasingly challenged by irrigation water scarcity, however covering paddy rice soils with films (ground cover rice production system: GCRPS) can significantly reduce water demand as well as overcome temperature limitations at the beginning of the vegetation period resulting in increased grain yields in colder regions of rice production with seasonal water shortages. It has been speculated that the increased soil aeration and temperature under GCRPS may result in losses of soil organic carbon and nitrogen stocks. Here we report on a regional scale experiment, conducted by sampling paired adjacent Paddy and GCRPS fields at 49 representative sites in the Shiyan region, which is typical for many mountainous areas across China. Parameters evaluated included soil C and N stocks, soil physical and chemical properties, potential carbon mineralization rates, fractions of soil organic carbon and stable carbon isotopic composition of plant leaves. Furthermore, root biomass was quantified at maximum tillering stage at one of our paired sites. Against expectations the study showed that: (1) GCRPS significantly increased soil organic C and N stocks 5-20 years following conversion of production systems, (2) there were no differences between GCRPS and Paddy in soil physical and chemical properties for the various soil depths with the exception of soil bulk density, (3) GCRPS had lower mineralization potential for soil organic C compared with Paddy over the incubation period, (4) GCRPS showed lower ?15N in the soils and plant leafs indicating less NH3 volatilization in GCRPS than in Paddy; and (5) GCRPS increased yields and root biomass in all soil layers down to 40 cm depth. Our results suggest that GCRPS is an innovative rice production technique that not only increases yields using less irrigation water, but that it also is environmentally beneficial due to increased soil C and N stocks at regional scale.

  10. Leachate treatment in landfills

    SciTech Connect

    Zolten, N.G. )

    1991-05-01

    This article describes the origins of sanitary landfill leachates, their potential for contamination of surrounding soil and groundwater, and characterization and techniques for treating this extremely high-strength municipal wastewater to required standards by biological processes. Topics include leachate characterization, effluent standards and treatment by two stage activated sludge process.

  11. Frequency and distribution patterns of zoosporic fungi from moss-covered and exposed forest soils.

    PubMed

    Letcher, Peter M; Powell, Martha J

    2002-01-01

    Uniflagellate zoosporic "fungi" (=Chytridiomycota and the zoosporic protista Hyphochytriomycota) are common inhabitants of soil. However, at what scale differences in their spatial distribution can be detected is poorly known. The first objective of this study was to assess the association of organismal distribution and frequency with two microhabitats: moss-covered and exposed forest soils, at four macroscopically similar but spatially separate sites in the Blue Ridge and Allegheny Mountains of Virginia. The second objective was to provide statistically either acceptance or denial of inferences derived from sampling regimes involving a more limited number of samples. To evaluate the scale where distributional differences may occur within a site, protocols involved four collection regimes and random point and linear transect sampling. Chytrid frequency on thalli of two moss genera was greatest in the soil surrounding and under the moss rhizoids. Random point sampling methods suggested differences in zoosporic fungal frequency between moss-covered soil and the exposed soil adjacent to mosses, as well as between two moss taxa. Linear transect sampling methods also suggested differences in zoosporic fungal frequencies between moss-covered soil and soil proximal to mosses. However, statistical analysis of random point samples using a goodness-of-fit test demonstrated that there was no significant difference in frequency of zoosporic fungi from moss-covered soil and exposed soil proximal to mosses. More importantly, there was a significant difference in the frequency of ubiquitous and common zoosporic fungal species between different moss/soil complexes. This study demonstrates that differences in chytrid distribution can be detected at a microscale while at a larger scale, similarity in frequency and distribution was found. PMID:21156550

  12. Salt and N leaching and soil accumulation due to cover cropping practices

    NASA Astrophysics Data System (ADS)

    Gabriel, J. L.; Quemada, M.

    2012-04-01

    Nitrate leaching beyond the root zone can increase water contamination hazards and decrease crop available N. Cover crops used in spite of fallow are an alternative to reduce nitrate contamination in the vadose zone, because reducing drainage and soil mineral N accumulation. Cover crops can improve important characteristics in irrigated land as water retention capacity or soil aggregate stability. However, increasing evapotranspiration and consequent drainage below the root system reduction, could lead to soil salt accumulation. Salinity affects more than 80 million ha of arable land in many areas of the world, and one of the principal causes for yield reduction and even land degradation in the Mediterranean region. Few studies dealt with both problems at the same time. Therefore, it is necessary a long-term evaluation of the potential effect on soil salinity and nitrate leaching, in order to ensure that potential disadvantages that could originate from soil salt accumulation are compensated with all advantages of cover cropping. A study of the soil salinity and nitrate leaching was conducted during 4 years in a semiarid irrigated agricultural area of Central Spain. Three treatments were studied during the intercropping period of maize (Zea mays L.): barley (Hordeum vulgare L.), vetch (Vicia villosa L.) and fallow. Cover crops were killed in March allowing seeding of maize of the entire trial in April, and all treatments were irrigated and fertilised following the same procedure. Before sowing, and after harvesting maize and cover crops, soil salt and nitrate accumulation was determined along the soil profile. Soil analysis was conducted at six depths every 0.20 m in each plot in samples from four 0 to 1.2-m depth holes dug. The electrical conductivity of the saturated paste extract and soil mineral nitrogen was measured in each soil sample. A numerical model based on the Richards water balance equation was applied in order to calculate drainage at 1.2 m depth, using daily soil water content measurements, based on calibrated capacitance probes. Our results showed that drainage during the irrigated period was minimized, because irrigation water was adjusted to crop needs, leading to soil salt and nitrate accumulation on the upper layers after maize harvest. Then, during the intercrop period, most of salt and nitrate leaching occurred. Cover crops use led to shorter drainage period, lower drainage water amount and lower nitrate and salt leaching than treatment with fallow. These effects were related with a larger nitrate accumulation in the upper layers of the soil after cover crop treatments. But there was not soil salt accumulation increase in treatments with cover crops, and even decreased after years with a large cover crop biomass production. Then, adoption of cover crops in this kind of irrigated cropping system reduced water drainage beyond the root zone, salt and nitrate leaching diminished as a consequence but did not lead to salt accumulation in the upper soil layers. Acknowledgements: Financial support by CICYT, Spain (ref. AGL2005-00163 and AGL 2011-24732) and Comunidad de Madrid (project AGRISOST, S2009/AGR-1630).

  13. Effect of land-use practice on soil moisture variability for soils covered with dense forest vegetation of Puerto Rico

    NASA Technical Reports Server (NTRS)

    Tsegaye, T.; Coleman, T.; Senwo, Z.; Shaffer, D.; Zou, X.

    1998-01-01

    Little is known about the landuse management effect on soil moisture and soil pH distribution on a landscape covered with dense tropical forest vegetation. This study was conducted at three locations where the history of the landuse management is different. Soil moisture was measured using a 6-cm three-rod Time Domain Reflectometery (TDR) probe. Disturbed soil samples were taken from the top 5-cm at the up, mid, and foothill landscape position from the same spots where soil moisture was measured. The results showed that soil moisture varies with landscape position and depth at all three locations. Soil pH and moisture variability were found to be affected by the change in landuse management and landscape position. Soil moisture distribution usually expected to be relatively higher in the foothill (P3) area of these forests than the uphill (P1) position. However, our results indicated that in the Luquillo and Guanica site the surface soil moisture was significantly higher for P1 than P3 position. These suggest that the surface and subsurface drainage in these two sites may have been poor due to the nature of soil formation and type.

  14. Paleo-shade: woody cover, stable isotopes, soil temperature, and soil organic matter in tropical ecosystems (Invited)

    NASA Astrophysics Data System (ADS)

    Cerling, T. E.; Andanje, S.; Kimutai, D.; Levin, N. E.; Mace, W. D.; Macharia, A. N.; Passey, B. H.; Remien, C.; Wynn, J. G.

    2010-12-01

    The δ13C value of soil carbon is directly related to the fraction of C4 biomass in soils because of the difference in isotope discrimination between plants using the C3 (trees, shrubs, and herbs) and C4 (primarily tropical grasses) photosynthetic pathways. Almost all woody plants use the C3 photosynthetic pathway, and therefore the fraction of woody cover in tropical ecosystems has an important influence on the fraction of C4 biomass in soils. Surveys of tropical ecosystems from East Africa and Australia show that little C4 biomass is evident until woody cover fraction falls below 0.5. This is due to several factors, including the shading effect of woody cover and retention of soil moisture; these decrease the daily maximum ground surface temperature and decrease water stress. Thus, C3 photosynthesis is favored relative to C4 photosynthesis in well-shaded environments compared to nearby open environments. Between 0.0 and 0.5 fraction woody cover, the δ13C of soil organic matter is strongly correlated with the fraction of woody cover. However, as the woody cover approaches 0, in some semi-arid ecosystems a significant fraction of C3 herbaceous plants are present. Thus some “grasslands” may have a significant fraction of C3 herbaceous cover. Paleosols are an indicator of the fraction of C4 biomass because of their preserved δ13C values in organic matter and in pedogenic carbonate. This δ13C signal can be used as an indicator of “paleo-shade” or fraction of woody-cover in the geological record. Δ47C values of paleosols for much of the past 4 Ma in the Turkana Basin in northern Kenya and the Awash Basin in Ethiopia indicate ecosystems similar to modern grasslands to woody grasslands (using the UNESCO classification for tropical ecosystems); these are commonly known as savannas. Thus some of the most important localities documenting hominin evolution show strong evidence for a savanna environment. This interpretation is supported by independent evidence from ‘carbonate clumped-isotope’ thermometry of Turkana Basin paleosol carbonates: this method reveals that deep (>50 cm) soil temperatures were ~30 - 35C during carbonate-forming intervals of the past 4 Ma, a temperature range significantly higher than temperatures of modern tropical forest soils, but similar to soil temperatures in open arid environments such as the present day Turkana Basin.

  15. The role of topography and surface cover upon soil formation along hillslopes in arid climates

    NASA Astrophysics Data System (ADS)

    Yair, Aaron

    1990-09-01

    Two north-facing soil toposequences were selected from within the northern Negev desert, Israel, where average annual rainfall ranges from 70 to 200 mm. Both slopes are composed of an upper rocky and a lower colluvial section. Similar trends were found along both slopes. A high salt content was characteristic of soils at the top of the slope; salinity decreased downslope within the rocky slope section. The opposite occurred along the colluvial slopes, with salinity increasing sharply downslope. At any location along the slopes the northernmost soil toposequence site (160 mm average annual rainfall) represents, from a pedological point of view, an environment which is far more arid than its climatologically drier, more southern counterpart. The explanation provided for the variation of soil proporties at the scale of single hillslopes and at the regional scale is the same. It is contended that water input into the soil, and therefore leaching intensity, is positively related to the ratio of bedrock/soil cover. Rocky areas have limited infiltration, thus yielding high runoff rates into adjoining soil-covered areas, and contribute to water concentration, deeper infiltration and leaching intensity. Soil or sediment-covered areas having relatively high absorption capacities will experience reduced runoff, shallow infiltration and decreased water availability for leaching. This leads over time to salt accumulation at a shallow depth. The decrease in rock/soil ratio downslope within the colluvium is therefore held responsible for the corresponding increase in salinity. Similarly, the greater salinity of the soils in the northern site is explained by the fact that its rock/soil ratio is lower than in the southern area. The theoretical and practical implications regarding the relationship between climatic change and landscape evolution in arid areas are briefly discussed.

  16. Using high-resolution radar images to determine vegetation cover for soil erosion assessments.

    PubMed

    Bargiel, D; Herrmann, S; Jadczyszyn, J

    2013-07-30

    Healthy soils are crucial for human well-being. Because soils are threatened worldwide, politicians recognize the need for soil protection. For example, the European Commission has launched the Thematic Strategy for Soil Protection, which requests the European member states to identify high risk areas for soil degradation. Most states use the Universal Soil Loss Equation (USLE) to assess soil erosion risk at the national scale. The USLE includes different factors, one of them is the vegetation cover and management factor (C factor). Modern satellite-based radar sensors now provide highly accurate vegetation cover data, enabling opportunities to improve the accuracy of the C factor. The presented study proves the suitability for C factor determination based on a multi-temporal classification of high-resolution radar images. Further USLE factors were derived from existing data sources (meteorological data, soil maps, digital elevation model) to conduct an USLE-based soil erosion assessment. The resulting map illustrates a qualitative assessment for soil erosion risk within a plot of about 7*12km in an agricultural region in Poland that is very susceptible to soil erosion processes. A high erosion risk of more than 10 tonnes per ha and year was assessed to occur on 13.6% (646ha) of the agricultural areas within the investigated plot. Further 7.8% (372ha) of agricultural land is threaten by a medium risk of 5-10 tonnes per ha and year. Such a spatial information about areas of high or medium soil erosion risk are crucial for the development of strategies for the protection of soils. PMID:23624425

  17. Managing soil nitrate with cover crops and buffer strips in Sicilian vineyards

    NASA Astrophysics Data System (ADS)

    Novara, A.; Gristina, L.; Guaitoli, F.; Santoro, A.; Cerdà, A.

    2013-04-01

    When soil nitrate levels are inadequate, plants suffer nitrogen deficiency but when the levels are excessive, nitrates (NO3-N) can pollute surface and subsurface waters. Strategies to reduce the nitrate pollution are necessary to reach a sustainable use of resources such as soil, water and plant. Buffer strips and cover crops can contribute to the management of soil nitrates, but little is known of their effectiveness in semiarid vineyards plantations. The experimental site, a 10 m wide and 80 m long area at the bottom of a vineyard was selected in Sicily. The soil between vine rows and upslope of the buffer strip (seeded with Lolium perenne) and non-buffer strips (control) was managed conventionally and with one of two cover crops (Triticum durum and Vicia sativa cover crop). Soil nitrate was measured monthly and nitrate movement was monitored by application of a 15N tracer to a narrow strip between the bottom of vineyard and the buffer and non-buffer strips. L. perenne biomass yield in the buffer strips and its isotopic nitrogen content were monitored. V. sativa cover crop management contribute with an excess of nitrogen, and the soil management determined the nitrogen content at the buffer areas. A 6 m buffer strip reduce the nitrate by 42% with and by 46% with a 9 m buffer strip.

  18. A validation of a thermal inertia approach to map soil water content on soils characterized by low fractional cover

    NASA Astrophysics Data System (ADS)

    Maltese, Antonino; Capodici, Fulvio; La Loggia, Goffredo; Corbari, Chiara; Mancini, Marco

    2013-10-01

    The assessment of the spatial distribution of soil water content could improve the effectiveness of agro-hydrological models. Although it is possible to retrieve the spatial distribution of the soil water content using thermal inertia, the main limit is its applicability to bare soils only. Recently, a variation of the thermal inertia approach has been setup also on vegetated soils characterized by low fractional cover. In particular, the methodology proposes to attenuate the solar radiation at the top of the canopy to the one reaching the soil trough an extinction factor. In situ data were acquired in June 2011 and July 2012 over two fields of maize and sunflowers; both were at their early growing stages. An airborneplatform provided images in the visible/near infrared and thermal infrared, both in day and night time. Results of the 2011 experiment demonstrated that the vegetation cover correction is required even with low fractional cover; indeed, not applying this correction would results in strong overestimation. The 2012 experiment (REFLEX) further validates the model on an independent dataset, thus, confirming the reliability of the methodology. Furthermore, a spatial resolution analysis highlighted that retrievals at low spatial resolution best compares with in situsoil water content than those obtained at high-resolution. Finally, the availability of a thermal image acquired after irrigating demonstrated the unreliability of the method when soil water content significantly changes between the two thermal acquisitions.

  19. Numerical Modeling of the Soil Cover System Performance from Hydrogeological Analysis

    NASA Astrophysics Data System (ADS)

    Min, D.; Cheong, Y.; Yim, G.; Baek, H.

    2008-05-01

    Decline of mining industry is drastic in production and consumption in Korea, and the number of operating mines has been reduced by more than 90 percent in last two decades. Environmental concern and the collapse of commercial viability has necessitated the government to close down uneconomical mines, and reclamation of mine waste dumps and the proper treatment of the mine drainage constitute the most important factors for regional rehabilitation programs. A dry soil cover system for mine waste is steadily increasing in Korea, to minimize the influx of water and oxygen into the waste dump. Traditional cover design procedures based on empirical or semi-quantitative analyses can be improved by implementing environmental and hydrological parameters including total precipitation, evapotranspiration, surface runoff, and infiltration associated with different cover configurations. The main objective of this study is to develop a standardized design procedure for dry cover systems to minimize environmental impacts in mine lands, securing both efficiency and long-term structural stability. A numerical analysis technique was adopted for selecting governing parameters which dictate hydrogeologic characteristics of the unsaturated zone in soil cover system. Variables included the soil water characteristic curve, hydraulic conductivity function, and water balance of the study area. A commercial finite element analysis software was applied for performance analysis of three soil cover systems including a simple growth medium, sand layer, and sand-clay-sand complex layer.

  20. Snow Cover Depletion and Soil Moisture Recharge at Three Cold Land Processes Experiment (CLPX) Meteorological Sites

    NASA Astrophysics Data System (ADS)

    Holcombe, J. D.; Elder, K.; Davis, R. E.

    2003-12-01

    With increasing concern regarding water supply in arid and semiarid regions, knowledge of water resources in the Earth's cold regions is critical. Snow-cover depletion and soil moisture recharge are elements used in hydrologic modeling and climate modeling, as well as remote sensing applications. Modeled snow-cover depletion and soil moisture recharge are important parameters in hydrologic forecasting. We evaluate the ability of a one-dimensional mass and energy balance model (SNTHERM.89) to predict snow-cover depletion and to test the accuracy of Fast All season Soil STrength (FASST) in modeling the evolution of soil moisture recharge based on data from three NASA Cold Land Processes Experiment (CLPX) sites. The objective is to evaluate the model's ability to predict observations at three CLPX sites: Buffalo Pass (near Steamboat Springs, CO); St. Louis Creek (in the Fraser Experimental Forest, CO); and Illinois River (located in North Park, CO). The three sites were chosen for their diverse climatic and physiographic differences. The Buffalo Pass site has a deep snowpack with discontinuous forest cover dominated by Englemann spruce (Picea englemannii) and alpine fir (Abies lasiocarpa). The St. Louis site has a moderate snowpack depth and forest cover dominated by lodgepole pine (Pinus contorta). The Illinois River site is irrigated grassland with no forest cover.

  1. Landfill restoration and biodiversity: a case of study in Northern Italy.

    PubMed

    Camerini, Giuseppe; Groppali, Riccardo

    2014-08-01

    Landfilling is a worldwide common waste treatment method. Final recovery usually consists of capping the area with top soil on which vegetation can grow. Depending on the suitability of the recovery pattern, landfill sites can work as potential reserve of semi-natural habitats. A recovery pattern applied to land reclamation of two hazardous waste landfills sited in Northern Italy (Po floodplain) was studied to assess the results in terms of biodiversity. These landfills lie within a landscape dominated by intensive agriculture. After final sealing, both landfills were covered by soil on which a meadow was sown and a hedgerow was planted around the borders. One of the compared areas was not provided with a pond and the hedgerow was incomplete. Butterflies and birds were used as indicators, and their seasonal abundance was related to habitat structure and ecological factors. Meadows grown on both areas supported a rich butterfly population (30 species), including some species that are by now uncommon in the Po floodplain. In both areas butterfly abundance was affected by summer drought. The birds' community included 57 species; 16 Species of European Conservation Concern (SPECs) were observed. Each bird community was different in the compared study areas because of their different size and habitat structure. For example, landfill A, provided with a pond and a more complex structure of the hedgerow, supported a richer birds community (52 species versus 39). Both restored landfills worked well as a stepping stone for migratory birds, but they were a reproductive habitat of poor quality. PMID:25161277

  2. Variability in soil CO2 efflux across distinct urban land cover types

    NASA Astrophysics Data System (ADS)

    Weissert, Lena F.; Salmond, Jennifer A.; Schwendenmann, Luitgard

    2015-04-01

    As a main source of greenhouse gases urban areas play an important role in the global carbon cycle. To assess the potential role of urban vegetation in mitigating carbon emissions we need information on the magnitude of biogenic CO2 emissions and its driving factors. We examined how urban land use types (urban forest, parklands, sportsfields) vary in their soil CO2 efflux. We measured soil CO2 efflux and its isotopic signature, soil temperature and soil moisture over a complete growing season in Auckland, New Zealand. Soil physical and chemical properties and vegetation characteristics were also measured. Mean soil CO2 efflux ranged from 4.15 to 12 ?mol m-2 s-1. We did not find significant differences in soil CO2 efflux among land cover types due to high spatial variability in soil CO2 efflux among plots. Soil (soil carbon and nitrogen density, texture, soil carbon:nitrogen ratio) and vegetation characteristics (basal area, litter carbon density, grass biomass) were not significantly correlated with soil CO2 efflux. We found a distinct seasonal pattern with significantly higher soil CO2 efflux in autumn (Apr/May) and spring (Oct). In urban forests and sportsfields over 80% of the temporal variation was explained by soil temperature and soil water content. The ?13C signature of CO2 respired from parklands and sportsfields (-20 permil - -25 permil) were more positive compared to forest plots (-29 permil) indicating that parkland and sportsfields had a considerable proportion of C4 grasses. Despite the large intra-urban variability, our results compare to values reported from other, often climatically different cities, supporting the hypothesis of homogenization across urban areas as a result of human management practices.

  3. Landfill methane oxidation response to vegetation, fertilization, and liming

    SciTech Connect

    Hilger, H.A.; Wollum, A.G.; Barlaz, M.A.

    2000-02-01

    Landfills are the fourth largest global source and the largest US source (USDOE, 1997) of anthropogenic CH{sub 4} emissions. Since gram-for-gram, CH{sub 4} has 21 times the 100-yr global-warming potential of CO{sub 2} (USEPA, 1990). CH{sub 4} release into the atmosphere has important implications for global climate change. This study was conducted to evaluate the effects of vegetation, N fertilizers, and lime addition on landfill CH{sub 4} oxidation. Columns filled with compacted sandy loam and sparged with synthetic landfill gas were used to simulate a landfill cover. Grass-topped and bare-soil columns reduced inlet CH{sub 4} by 47 and 37%, respectively, at peak uptake; but the rate for both treatments was about 18% at steady state. Nitrate and NH{sub 4} amendments induced a more rapid onset of CH{sub 4} oxidation relative to KCl controls. However, at steady state, NH{sub 4} inhibited CH{sub 4} oxidation in bare columns but not in grassed columns. Nitrate addition produced no inhibitory effects. Lime addition to the soil consistently enhanced CH{sub 4} oxidation. In all treatments, CH{sub 4} consumption increased to a peak value, then declined to a lower steady-state value; and all gassed columns developed a pH gradient. Neither nutrient depletion nor protozoan grazing could explain the decline from peak oxidation levels. Ammonium applied to grassed cover soil can cause transient reductions in CH{sub 4} uptake, but there is no evidence that the inhibition persists. The ability of vegetation to mitigate NH{sub 4} inhibition indicates that results from bare-soil tests may not always generalize to vegetated landfill caps.

  4. Topography Mediates the Influence of Cover Crops on Soil Nitrate Levels in Row Crop Agricultural Systems

    PubMed Central

    Ladoni, Moslem; Kravchenko, Alexandra N.; Robertson, G. Phillip

    2015-01-01

    Supplying adequate amounts of soil N for plant growth during the growing season and across large agricultural fields is a challenge for conservational agricultural systems with cover crops. Knowledge about cover crop effects on N comes mostly from small, flat research plots and performance of cover crops across topographically diverse agricultural land is poorly understood. Our objective was to assess effects of both leguminous (red clover) and non-leguminous (winter rye) cover crops on potentially mineralizable N (PMN) and NO3--N levels across a topographically diverse landscape. We studied conventional, low-input, and organic managements in corn-soybean-wheat rotation. The rotations of low-input and organic managements included rye and red clover cover crops. The managements were implemented in twenty large undulating fields in Southwest Michigan starting from 2006. The data collection and analysis were conducted during three growing seasons of 2011, 2012 and 2013. Observational micro-plots with and without cover crops were laid within each field on three contrasting topographical positions of depression, slope and summit. Soil samples were collected 4–5 times during each growing season and analyzed for NO3--N and PMN. The results showed that all three managements were similar in their temporal and spatial distributions of NO3—N. Red clover cover crop increased NO3--N by 35% on depression, 20% on slope and 32% on summit positions. Rye cover crop had a significant 15% negative effect on NO3--N in topographical depressions but not in slope and summit positions. The magnitude of the cover crop effects on soil mineral nitrogen across topographically diverse fields was associated with the amount of cover crop growth and residue production. The results emphasize the potential environmental and economic benefits that can be generated by implementing site-specific topography-driven cover crop management in row-crop agricultural systems. PMID:26600462

  5. Topography Mediates the Influence of Cover Crops on Soil Nitrate Levels in Row Crop Agricultural Systems.

    PubMed

    Ladoni, Moslem; Kravchenko, Alexandra N; Robertson, G Phillip

    2015-01-01

    Supplying adequate amounts of soil N for plant growth during the growing season and across large agricultural fields is a challenge for conservational agricultural systems with cover crops. Knowledge about cover crop effects on N comes mostly from small, flat research plots and performance of cover crops across topographically diverse agricultural land is poorly understood. Our objective was to assess effects of both leguminous (red clover) and non-leguminous (winter rye) cover crops on potentially mineralizable N (PMN) and [Formula: see text] levels across a topographically diverse landscape. We studied conventional, low-input, and organic managements in corn-soybean-wheat rotation. The rotations of low-input and organic managements included rye and red clover cover crops. The managements were implemented in twenty large undulating fields in Southwest Michigan starting from 2006. The data collection and analysis were conducted during three growing seasons of 2011, 2012 and 2013. Observational micro-plots with and without cover crops were laid within each field on three contrasting topographical positions of depression, slope and summit. Soil samples were collected 4-5 times during each growing season and analyzed for [Formula: see text] and PMN. The results showed that all three managements were similar in their temporal and spatial distributions of NO3-N. Red clover cover crop increased [Formula: see text] by 35% on depression, 20% on slope and 32% on summit positions. Rye cover crop had a significant 15% negative effect on [Formula: see text] in topographical depressions but not in slope and summit positions. The magnitude of the cover crop effects on soil mineral nitrogen across topographically diverse fields was associated with the amount of cover crop growth and residue production. The results emphasize the potential environmental and economic benefits that can be generated by implementing site-specific topography-driven cover crop management in row-crop agricultural systems. PMID:26600462

  6. Size-fractionation and characterization of landfill leachate and the improvement of Cu{sup 2+} adsorption capacity in soil and aged refuse

    SciTech Connect

    Lou Ziyang; Chai Xiaoli; Niu Dongjie; Ou Yuanyang; Zhao Youcai

    2009-01-15

    Leachate was collected from an anaerobic lagoon at Shanghai Laogang refuse landfill, the largest landfill in China, and the sample was separated into six fractions using micro-filtration membranes, followed by ultra-filtration membranes. Several parameters of the samples were measured, including chemical oxygen demand (COD), total organic carbon (TOC), total solids (TS), pH, total phosphate (TP), total nitrogen (TN), fixed solids (FS), NH{sub 4}{sup +}, orthophosphate, color, turbidity, and conductivity. These parameters were then quantitatively correlated with the molecular weight cutoff of the membrane used. Organic matter in the dissolved fraction (MW < 1 kDa) predominated in the leachate, accounting for 65% of TOC. Thermal infrared spectroscopy was used to characterize the filter residues. Asymmetric and symmetric stretching of methyl and methylene groups, and of functional groups containing nitrogen and oxygen atoms, were observed. In addition, the ability of two different samples to adsorb heavy metals was tested. Cu{sup 2+} was chosen as the representative heavy metal in this study, and the samples were soil; aged refuse, which had spent 8 years in a conventional sanitary landfill; and samples of soil and aged refuse treated for 48 h with leachate in the ratio of 5 g of sample per 50 ml of leachate. Cu{sup 2+} uptake by the raw soil was {approx}4.60 {mu}g/g, while uptake by the leachate-contacted soil and leachate-contacted aged refuse were 5.66 and 5.11 {mu}g/g, respectively. These results show that the organic matter in the leachate enhanced the capacity of aqueous solutions to adsorb Cu{sup 2+}.

  7. Ground cover rice production systems increase soil carbon and nitrogen stocks at regional scale

    NASA Astrophysics Data System (ADS)

    Liu, M.; Dannenmann, M.; Lin, S.; Saiz, G.; Yan, G.; Yao, Z.; Pelster, D. E.; Tao, H.; Sippel, S.; Tao, Y.; Zhang, Y.; Zheng, X.; Zuo, Q.; Butterbach-Bahl, K.

    2015-08-01

    Rice production is increasingly limited by water scarcity. Covering paddy rice soils with films (so-called ground cover rice production system: GCRPS) can significantly reduce water demand as well as overcome temperature limitations at the beginning of the growing season, which results in greater grain yields in relatively cold regions and also in those suffering from seasonal water shortages. However, it has been speculated that both increased soil aeration and temperature under GCRPS result in lower soil organic carbon and nitrogen stocks. Here we report on a regional-scale experiment conducted in Shiyan, a typical rice-producing mountainous area of China. We sampled paired adjacent paddy and GCRPS fields at 49 representative sites. Measured parameters included soil carbon (C) and nitrogen (N) stocks (to 1 m depth), soil physical and chemical properties, δ15N composition of plants and soils, potential C mineralization rates, and soil organic carbon (SOC) fractions at all sampling sites. Root biomass was also quantified at one intensively monitored site. The study showed that: (1) GCRPS increased SOC and N stocks 5-20 years following conversion from traditional paddy systems; (2) there were no differences between GCRPS and paddy systems in soil physical and chemical properties for the various soil depths, with the exception of soil bulk density; (3) GCRPS increased above-ground and root biomass in all soil layers down to a 40 cm depth; (4) δ15N values were lower in soils and plant leaves indicating lower NH3 volatilization losses from GCRPS than in paddy systems; and (5) GCRPS had lower C mineralization potential than that observed in paddy systems over a 200-day incubation period. Our results suggest that GCRPS is an innovative production technique that not only increases rice yields using less irrigation water, but that it also increases SOC and N stocks.

  8. Effects of winter cover crop, soil amendment, and variety on organic rice production and greenhouse gas emissions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nitrogen supply and disease are two main challenges in organic rice production. Cover crop and soil amendment can be options to increase soil N while keeps rice health. The objective of this study was to test the effects of cover crop and soil amendment on the production of organic rice. Three popul...

  9. COVER CROPS AND CULTIVATION: IMPACTS ON SOIL N DYNAMICS, NITROUS OXIDE EFFLUX, AND MICROBIOLOGICAL FUNCTION IN A MEDITERRANEAN VINEYARD AGROECOSYSTEM

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Impacts of soil tillage and cover crops on soil nitrogen (N) dynamics and microbiological function were investigated in a vineyard grown in Californias Mediterranean climate. We compared soil N dynamics, N availability and N2O emissions in a vineyard agroecosystem of two cover crops [Trios 102 (Tri...

  10. Soil moisture and soil loss study under different cover densities in Ultisolsin Pernambuco State semi-arid (Brazil)

    NASA Astrophysics Data System (ADS)

    Borges, T. K. S.; Montenegro, A. A. A.; Santos, T. E. M.; Silva Junior, V. P.; Siqueira, G. M.

    2012-04-01

    Throughout Brazil occurs a large loss of soil and water runoff due to soil erosion especially in rural areas. The soil moisture monitoringhas been a practice increasingly important in agriculture, especially in regions where water scarcity is high and rainfed cropping is adopted. The soil cover is one of the factors that minimize these effects of degradation arising from agricultural land use. To monitor the water content in the soil profile, point measurements were performed using an FDR equipment, which is a capacitance probe, Diviner 2000 model, the Sentek Pty Ltd, Australia. The objective of this study was to investigate the dynamics of soil water content under different types of ground cover, using a probe and the Diviner soil loss in the semi-arid Pernambuco. The study was carried out in the Municipality of Pesqueira-PE, located in the State of Pernambuco, in the Alto Ipanema Representative Basin, with average annual rainfall of 730 mm and average annual potential evapotranspiration of 1683 mm. The soil of the study areas is classified as Eutrophic Yellow Ultisol abruptly (Area A) and typical Eutrophic Yellow Ultisol (Area B). For this, study three experimental plots were installed in two different areas, totalling six plots, bounded by brick, with 4.5 m wide and 11 m long in the direction of the slope, under three soil cover conditions. The treatments involved in this study are: bare soil (SD); with cactus (P) and natural cover (CN). The water content in soil was evaluated at 0.10, 0.20 and 0.30 m at the soil profile and sediment sampling were carried out fortnightly between April and July 2011 (rainy season). In this work we used cumulative precipitation for seven and fourteen days before the readings with the Divinerprobe. The highest rainfall is concentrated during the months of May and July of 2011, and May is the month with the highest cumulative rainfall. April received the lowest rainfall, considered the driest. The water content in the soil indicates that in all treatments there was a greater storage of water with increased rainfall and reduced runoff. In area A treatment with CN had a larger increase in moisture at all depths. These results prove that the presence of vegetation is important for the semi-arid region, especially during drought periods. In the area B, at a depth of 0.10 m, the cactus had the highest increase of moisture, while at depths of 0.20 and 0.30 m above the ground there was a lower water storage. This result is related to the fact that in areas with high vegetation density results in a higher water consumption due to the demand of the plants, resulting in less moisture compared to the bare soil plot. The erosion results obtained show that the highest soil losses occurred in the condition without cover and it can be verified that it was influenced by the presence or absence of cover used and demonstrated to be effective (CN and P) to control erosion, providing a greater protective effect in the soil to reduce the area exposed to the raindrops impact.

  11. Soils and the soil cover of the arkaim reserve (Steppe Zone of the Trans-Ural Region)

    NASA Astrophysics Data System (ADS)

    Prikhod'ko, V. E.; Ivanov, I. V.; Manakhov, D. V.; Manakhova, E. V.

    2012-08-01

    Soils of the Arkaim Reserve in the area around a unique settlement-fortress of the Bronze Age in Chelyabinsk oblast have been studied. These soils are generally typical of the entire Trans-Ural Plateau. The soil properties are characterized in detail on the basis of factual data on 170 soil pits and four soil catenas. The soil cover of the reserve is specified into six geomorphic groups: (a) denudational surfaces of the low mountains, (b) accumulative-denudational surfaces of the low mountains, (c) denudational-accumulative plain surfaces, (d) lacustrine-alluvial plain surfaces, (e) floodplain surfaces, and (f) slopes and bottoms of the local ravines and hollows. Chernozems occupy about 50% of the reserve; solonetzes and saline soils, 32%; meadow chernozems, 7%; and forest soils, 1%. The soils of the reserve are relatively thin; they have a distinct tonguing of the humus horizon and are often saline and solonetzic. The latter properties are inherited from the parent materials and are preserved in the soils for a long time under the conditions of a dry continental climate. The genetic features of the soils differ in dependence on the composition and age of the parent materials. With respect to the thickness of the soil profiles and the reserves of soil humus, the soils can be arranged into the following lithogenic sequence: the soils developed from the eluvium of igneous rocks-redeposited kaolin clay-montmorillonite-hydromica nonsaline and saline loams and clays. The content of Corg in the upper 20 cm varies from 2.5 to 5.6%, and the reserves of Corg in the layers of 0-0.5 and 0-1.0 m reach 57-265 and 234-375 t/ha, respectively. The soils of pastures subjected to overgrazing occupy two-thirds of the reserve. Their humus content is 10-16% higher in comparison with that in the analogous plowed soils. Another characteristic feature of the humus in the soils of the pastures is its enrichment in the labile fraction (28-40% of Corg).

  12. Soil Moisture and Snow Cover: Active or Passive Elements of Climate

    NASA Technical Reports Server (NTRS)

    Oglesby, Robert J.; Marshall, Susan; Erickson, David J., III; Robertson, Franklin R.; Roads, John O.; Arnold, James E. (Technical Monitor)

    2002-01-01

    A key question is the extent to which surface effects such as soil moisture and snow cover are simply passive elements or whether they can affect the evolution of climate on seasonal and longer time scales. We have constructed ensembles of predictability studies using the NCAR CCM3 in which we compared the relative roles of initial surface and atmospheric conditions over the central and western U.S. in determining the subsequent evolution of soil moisture and of snow cover. Results from simulations with realistic soil moisture anomalies indicate that internal climate variability may be the strongest factor, with some indication that the initial atmospheric state is also important. Model runs with exaggerated soil moisture reductions (near-desert conditions) showed a much larger effect, with warmer surface temperatures, reduced precipitation, and lower surface pressures; the latter indicating a response of the atmospheric circulation. These results suggest the possibility of a threshold effect in soil moisture, whereby an anomaly must be of a sufficient size before it can have a significant impact on the atmospheric circulation and climate. Results from simulations with realistic snow cover anomalies indicate that the time of year can be crucial. When introduced in late winter, these anomalies strongly affected the subsequent evolution of snow cover. When introduced in early winter, however, little or no effect is seen on the subsequent snow cover. Runs with greatly exaggerated initial snow cover indicate that the high reflectivity of snow is the most important process by which snow cover can impact climate, through lower surface temperatures and increased surface pressures. The results to date were obtained for model runs with present-day conditions. We are currently analyzing runs made with projected forcings for the 21st century to see if these results are modified in any way under likely scenarios of future climate change. An intriguing new statistical technique involving 'clustering' is developed to assist in this analysis.

  13. Are biodiversity indices of spontaneous grass covers in olive orchards good indicators of soil degradation?

    NASA Astrophysics Data System (ADS)

    Taguas, E. V.; Arroyo, C.; Lora, A.; Guzmán, G.; Vanderlinden, K.; Gómez, J. A.

    2015-03-01

    Spontaneous grass covers are an inexpensive soil erosion control measure in olive orchards. Olive farmers allow grass to grow on sloping terrain to comply with the basic environmental standards derived from the Common Agricultural Policy (CAP). However, to date there are very few studies assessing the environmental quality and extent of such covers. In this study, we described and compared the biodiversity indicators associated to herbaceous vegetation in two contrasting olive orchards in order to evaluate its relevance and quality. In addition, biodiversity patterns and their relationships with environmental factors such as soil type and properties, precipitation, topography and soil management were analyzed. Different grass cover biodiversity indices were evaluated in two olive orchard catchments under conventional tillage and no tillage with grass cover, during 3 hydrological years (2011-2013). Seasonal samples of vegetal material and pictures in a permanent grid (4 samples ha-1) were taken to characterize the temporal variations of the number of species, frequency, diversity and transformed Shannon's and Pielou's indices. Sorensen's index obtained in the two olive orchard catchments showed notable differences in composition, probably linked with the different site conditions. The catchment with the best site conditions (deeper soil and higher precipitation), with average annual soil losses over 10 t ha-1 and a more intense management, presented the highest biodiversity indices. In absolute terms, the diversity indices were reasonably high in both catchments, despite the fact that agricultural activity usually severely limits the landscape and the variety of species. Finally, a significantly higher content of organic matter in the first 10 cm of soil was found in the catchment with the worst site conditions, average annual soil losses of 2 t ha-1 and the least intense management. Therefore, the biodiversity indicators associated to weeds were not found to be suitable for describing the soil degradation in the study catchments.

  14. Considerations over the distribution of the organic matter in the soil cover of Transylvania Plain (Romania)

    NASA Astrophysics Data System (ADS)

    Cacovean, Horia; Man, Titus; Rusu, Teodor

    2010-05-01

    Considerations over the distribution of the organic matter in the soil cover of Transylvania Plain (Romania) Horea Cacovean*, Titus Man**, Teodor Rusu*** *OSPA-Cluj- 1Faglui street, Cluj Napoca, RO-40048, Romania- turda75@yahoo.com ** Faculty of Geographie, University of Babes-Bolyai, 5-7 Clinicilor street, Cluj Napoca, RO-400006, Romania *** Faculty of Agriculture, USAMV, 3-5 Calea Manastur street,Cluj Napoca, RO-400372, Romania Soil degradation has become a major concern in the Transylvania Plain. Erosion, landslides, salinization, gleysation, and loss of humus are the main forms of soil deterioration in that region. This factsheet deals with the role of organic matter in soil productivity and the effects of various management practices and abandonment of the lands on soil organic matter. Soils in Transylvania Plain are analyzed concerning the amount of humus they contain. The influence of soil texture, climatic variables, and soil management on the qualitative soil humus content was studied in the top 20 cm of different managed loess soils of more then 100 profiles along a climosequence in that region. Taken together, soil, landform, land use and vegetation data suggest: (1) summit positions are relatively stable with immobilizing humus environments; (2) the content of humus increase progressively down steep at the contact with the floodplains; 3) without the influx of organic materials, erodible backslopes may become humus depleted as it happen the poor inputs of grassland and forest litter are mixed with surface soil horizon; 4) influx of mixed sediment and organic materials from backslopes maintains concentrations of humus on footslopes and toeslopes. This influence was more pronounced in the heavy clayey soils, suggesting that the accumulation of humus was enhanced by organo-mineral interactions. Entrenchment of drainage ways can circumvent these translocation processes. The results underscore the importance of functional connectivity between upland hillslopes and alluvial soils.

  15. Organic farming and cover crops as an alternative to mineral fertilizers to improve soil physical properties

    NASA Astrophysics Data System (ADS)

    Sánchez de Cima, Diego; Luik, Anne; Reintam, Endla

    2015-10-01

    For testing how cover crops and different fertilization managements affect the soil physical properties in a plough based tillage system, a five-year crop rotation experiment (field pea, white potato, common barley undersown with red clover, red clover, and winter wheat) was set. The rotation was managed under four different farming systems: two conventional: with and without mineral fertilizers and two organic, both with winter cover crops (later ploughed and used as green manure) and one where cattle manure was added yearly. The measurements conducted were penetration resistance, soil water content, porosity, water permeability, and organic carbon. Yearly variations were linked to the number of tillage operations, and a cumulative effect of soil organic carbon in the soil as a result of the different fertilization amendments, organic or mineral. All the systems showed similar tendencies along the three years of study and differences were only found between the control and the other systems. Mineral fertilizers enhanced the overall physical soil conditions due to the higher yield in the system. In the organic systems, cover crops and cattle manure did not have a significant effect on soil physical properties in comparison with the conventional ones, which were kept bare during the winter period. The extra organic matter boosted the positive effect of crop rotation, but the higher number of tillage operations in both organic systems counteracted this effect to a greater or lesser extent.

  16. Comparison of Seasonal Soil Microbial Process in Snow-Covered Temperate Ecosystems of Northern China

    PubMed Central

    Zhang, Xinyue; Wang, Wei; Chen, Weile; Zhang, Naili; Zeng, Hui

    2014-01-01

    More than half of the earth's terrestrial surface currently experiences seasonal snow cover and soil frost. Winter compositional and functional investigations in soil microbial community are frequently conducted in alpine tundra and boreal forest ecosystems. However, little information on winter microbial biogeochemistry is known from seasonally snow-covered temperate ecosystems. As decomposer microbes may differ in their ability/strategy to efficiently use soil organic carbon (SOC) within different phases of the year, understanding seasonal microbial process will increase our knowledge of biogeochemical cycling from the aspect of decomposition rates and corresponding nutrient dynamics. In this study, we measured soil microbial biomass, community composition and potential SOC mineralization rates in winter and summer, from six temperate ecosystems in northern China. Our results showed a clear pattern of increased microbial biomass C to nitrogen (N) ratio in most winter soils. Concurrently, a shift in soil microbial community composition occurred with higher fungal to bacterial biomass ratio and gram negative (G-) to gram positive (G+) bacterial biomass ratio in winter than in summer. Furthermore, potential SOC mineralization rate was higher in winter than in summer. Our study demonstrated a distinct transition of microbial community structure and function from winter to summer in temperate snow-covered ecosystems. Microbial N immobilization in winter may not be the major contributor for plant growth in the following spring. PMID:24667929

  17. Calculation set for design and optimization of vegetative soil covers Sandia National Laboratories, Albuquerque, New Mexico.

    SciTech Connect

    Peace, Gerald L.; Goering, Timothy James

    2005-02-01

    This study demonstrates that containment of municipal and hazardous waste in arid and semiarid environments can be accomplished effectively without traditional, synthetic materials and complex, multi-layer systems. This research demonstrates that closure covers combining layers of natural soil, native plant species, and climatic conditions to form a sustainable, functioning ecosystem will meet the technical equivalency criteria prescribed by the U. S. Environmental Protection Agency. In this study, percolation through a natural analogue and an engineered cover is simulated using the one-dimensional, numerical code UNSAT-H. UNSAT-H is a Richards. equation-based model that simulates soil water infiltration, unsaturated flow, redistribution, evaporation, plant transpiration, and deep percolation. This study incorporates conservative, site-specific soil hydraulic and vegetation parameters. Historical meteorological data are used to simulate percolation through the natural analogue and an engineered cover, with and without vegetation. This study indicates that a 3-foot (ft) cover in arid and semiarid environments is the minimum design thickness necessary to meet the U. S. Environmental Protection Agency-prescribed technical equivalency criteria of 31.5 millimeters/year and 1 x 10{sup -7} centimeters/second for net annual percolation and average flux, respectively. Increasing cover thickness to 4 or 5 ft results in limited additional improvement in cover performance.

  18. Soil Moisture and Snow Cover: Active or Passive Elements of Climate?

    NASA Technical Reports Server (NTRS)

    Oglesby, Robert J.; Marshall, Susan; Robertson, Franklin R.; Roads, John O.; Arnold, James E. (Technical Monitor)

    2001-01-01

    A key question in the study of the hydrologic cycle is the extent to which surface effects such as soil moisture and snow cover are simply passive elements or whether they can affect the evolution of climate on seasonal and longer time scales. We have constructed ensembles of predictability studies using the NCAR CCM3 in which we compared the relative roles of initial surface and atmospheric conditions over the central and western U.S. GAPP region in determining the subsequent evolution of soil moisture and of snow cover. We have also made sensitivity studies with exaggerated soil moisture and snow cover anomalies in order to determine the physical processes that may be important. Results from simulations with realistic soil moisture anomalies indicate that internal climate variability may be the strongest factor, with some indication that the initial atmospheric state is also important. The initial state of soil moisture does not appear important, a result that held whether simulations were started in late winter or late spring. Model runs with exaggerated soil moisture reductions (near-desert conditions) showed a much larger effect, with warmer surface temperatures, reduced precipitation, and lower surface pressures; the latter indicating a response of the atmospheric circulation. These results suggest the possibility of a threshold effect in soil moisture, whereby an anomaly must be of a sufficient size before it can have a significant impact on the atmospheric circulation and hence climate. Results from simulations with realistic snow cover anomalies indicate that the time of year can be crucial. When introduced in late winter, these anomalies strongly affected the subsequent evolution of snow cover. When introduced in early winter, however, little or no effect is seen on the subsequent snow cover. Runs with greatly exaggerated initial snow cover indicate that the high reflectivity of snow is the most important process by which snow cover can impact climate, through lower surface temperatures and increased surface pressures. In early winter, the amount of solar radiation is very small and so this albedo, effect is inconsequential while in late winter, with the sun higher in the sky and period of daylight longer, the effect is much stronger. The results to date were obtained for model runs with present-day conditions. We are currently analyzing runs made with projected forcings for the 21st century to see if these results are modified in any way under likely scenarios of future climate change.

  19. Methane emissions from landfills in Serbia and potential mitigation strategies: a case study.

    PubMed

    Stanisavljevic, Nemanja; Ubavin, Dejan; Batinic, Bojan; Fellner, Johann; Vujic, Goran

    2012-10-01

    Open dumping and landfilling have represented the predominant method of waste management in Serbia during the past decades. This practice resulted in over 3600 waste disposal sites distributed all over the country. The locations of the sites and their characteristics have been determined in the framework of the presented study. The vast majority of disposal sites (up to 3300) are characterized by small deposition depth of waste and total waste volumes of less than 10,000 m(3). Only about 50 landfills in Serbia contain more than 100,000 m(3) of waste. These large landfills are responsible for more than 95% of the total CH(4) emissions from waste disposal, which was assessed as 60,000 tons of CH(4) in 2010. The evaluation of different measures [soil cover, compost cover and landfill gas (LFG) systems] for mitigating greenhouse gas emissions from Serbian landfills indicated that enhanced microbial CH(4) oxidation (using a compost cover), as well as the installation of LFG systems, could generate net revenues as saved CH(4) emissions are creditable for the European Greenhouse Gas Emissions Trading Scheme. In total between 4 and 7 million tons of CO(2) equivalent emissions could be avoided within the next 20 years by mitigating CH(4) emissions from Serbian landfills. PMID:22751946

  20. Potential for leaching of heavy metals in open-burning bottom ash and soil from a non-engineered solid waste landfill.

    PubMed

    Gwenzi, Willis; Gora, Dorcas; Chaukura, Nhamo; Tauro, Tonny

    2016-03-01

    Bottom ash from open-burning of municipal waste practised in developing countries poses a risk of heavy metal leaching into groundwater. Compared to incineration ash, there is limited information on heavy metal leaching from open-burning ash and soil from non-engineered landfills. Batch and column experiments were conducted to address three specific objectives; (1) to determine aqua regia extractable concentrations of heavy metals in fresh ash, old ash and soil from beneath the landfill, (2) to determine the relationship between heavy metal leaching, initial and final pH of leaching solution, and aqua regia extractable concentrations, and (3) to determine the breakthrough curves of heavy metals in ashes and soil. Aqua regia extractable concentrations of Cd, Zn, Mn, Cu, Ni and Pb were significantly higher (p < 0.05) in fresh and old ashes than soil beneath landfill and uncontaminated soil (control). Increasing initial solution pH from 5 and 7 to 9 significantly reduced the mobility of Pb, Zn and Cu but not Cd whose mobility peaked at pH 7 and 9. Concentrations of desorbed heavy metals were not correlated with aqua regia extractable concentrations. Final pH of leachate rebounded to close to original pH of the material, suggesting a putative high buffering capacity for all materials. Both batch and column leaching showed that concentrations of leached heavy metals were disproportionately lower (<5%) than aqua regia extractable concentrations in most cases. The retardation of heavy metals was further evidenced by sigmoidal breakthrough curves. Heavy metal retention was attributed to precipitation, pH-dependent adsorption and formation of insoluble organo-metallic complexes at near-neutral to alkaline pH. Overall, the risk of heavy metal leaching from ash and soil from the waste dump into groundwater was low. The high pH and the presence of Zn, Fe, Mn and Cu make ash an ideal low-cost liming material and source of micronutrients particularly on acidic soils prevalent in sub-Saharan Africa. PMID:26766350

  1. Effects of multiple rolling cover crops on their termination, soil water and soil strength

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The impact of multiple rolling rye and mixture (rye, crimson clover and hairy vetch) using two rollers (straight bar, and two-stage) on termination rate, soil strength and soil moisture were evaluated in northern Alabama. In 2007 and 2008 growing seasons, both roller types effectively terminated rye...

  2. SOIL STRENGTH IN SE COASTAL PLAIN SOILS UNDER FALLOW AND WINTER RYE COVER

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In southeastern US Coastal Plain hardpan soils, inverse linear relationships have been found relating average soil strength within the top 60 cm of the profile and yield for corn (Zea mays L.), soybean (Glycine max L. Merr.), and wheat (Triticum aestivum L.). We expected to find a similar relationsh...

  3. Cover Crop and Liquid Manure Effects on Soil Quality Indicators in a Corn Silage System.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Due to a lack of surface residue and organic matter inputs, continuous corn (Zea mays L.) silage production is one of the most demanding cropping systems imposed on our soil resources. In this study, our objective was to determine if using cover/companion crops and/or applying low-solids liquid dair...

  4. Addition of cover crops enhances no-till potential for improving soil physical properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Interest in the use of cover crops (CC) is growing. Inclusion of CC may be a potential strategy to boost no-till performance by improving soil physical properties. To assess this potential, we utilized a wheat [Triticum aestivum (L.)]-grain sorghum [Sorghum bicolor (L.) Moench] rotation, four N rate...

  5. The impact of fall cover crops on soil nitrate and corn growth

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Incorporating cover crops into current production systems can have many beneficial impacts on the current cropping system including decreasing erosion, improving water infiltration, increasing soil organic matter and biological activity but in water limited areas caution should be utilized. A fiel...

  6. Long-term effects of compost and cover crops on soil phosphorus in two California agroecosystems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Inefficient P use in agriculture results in soil P accumulation and losses to surrounding ecosystems, highlighting the need to reduce external inputs and use them more efficiently. Composts reduce the need for mineral fertilizers by recycling P from wastes at the regional scale, whereas cover crops ...

  7. TILLAGE, COVER CROP, AND NITROGEN FERTILIZER SOURCE EFFECTS ON SOIL CARBON AND NITROGEN SEQUESTRATION.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 10-yr effect of combinations of tillage (no-till, mulch till, and conventional till), cover crop (rye vs. none), and N fertilization source and rate (0 and 100 kg N ha-1 from NH4NO3 and 100 and 200 kg N ha-1 from poultry manure) was evaluated on crop residues and soil organic C (SOC) and organic...

  8. Cover crops alter phosphorus soil fractions and organic matter accumulation in a Peruvian cacao agroforestry system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In many tropical soils, excessive weathering of primary minerals confounded by intense agricultural production has resulted in the depletion of organic matter and plant available forms of phosphorus (P). Long-term growth of cover crops in tropical agroforestry systems have been shown to influence nu...

  9. Cover crop, soil amendments, and variety effects on organic rice production in Texas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The major challenges in organic rice production include optimization of nutrient utilization, weed management, and variety selection. In this study, we tested the effects of two soil amendment products, two fertilizer rates, and three cover cropping systems (clover, ryegrass, and fallow) on organic ...

  10. Influence of Cover Crops in Rotation on Populations of Soil Nematodes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A pot experiment was carried out in south Florida to elucidate suppressive or antagonistic effects of several cover crops grown in rotation on soil nematode populations. The crops were two marigolds, Tagetes patula L. 'Dwarf Double French Mix' (MI), and Tagetes patula L. 'Lemon Drop' (MII), Indian m...

  11. Tillage and Cover Effects on Soil Microbial Properties and Fluometuron Degradation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field studies were conducted at Stoneville, MS, in 1994 and 1995 to determine the influence of tillage (no tillage [NT] or conventional tillage [CT]) and a ryegrass cover crop in a cotton production system on soil microbial populations and enzyme activity. Fluometuron degradation was evaluated unde...

  12. Frequent fire affects soil nitrogen and carbon in an African savanna by changing woody cover.

    PubMed

    Coetsee, Corli; Bond, William J; February, Edmund C

    2010-04-01

    When tropical and sub-tropical ecosystems burn, considerable amounts of N present in the biomass fuel may be released. This ultimately results in a loss of fixed N to the atmosphere. It is often assumed that this volatilization loss of N with frequent fire will result in a reduction of plant-available N and total system N. By changing the amount of woody biomass fire may, however, also have indirect effects on N and C dynamics. Here we consider the effects of 50 years of frequent fire on total soil N and soil organic C (SOC) and total soil N in a mesic savanna in the Kruger National Park, South Africa. We also determine how changes in woody biomass may affect total soil N and SOC. We measured soil and fine root N and C concentrations as well as total soil N and SOC pools in four burning treatments, including fire exclusion, of a long-term fire experiment. Our results show that regardless of soil depth, fire treatment had no significant effect on total soil N and SOC. Our results also show that under trees total soil N and SOC concentrations of the surface soil increase, and pools of N and SOC increase to a depth of 7 cm. However, the extent to which soil N and C dynamics differed under canopies and away from canopies was dependent on fire treatment. Our results show that the effect of fire on soil N and C is mediated both through the indirect effect of changes in woody cover and the direct effects of fire (volatilization losses of nutrients). We suggest that woody thickening in this mesic savanna will have pronounced effects on long-term N and C dynamics. PMID:20213154

  13. 19th Annual landfill gas symposium

    SciTech Connect

    1996-11-01

    This document contains the Proceedings of the 19th Annual Landfill Gas Symposium sponsored by the Solid Waste Association of America (SWANA), held on March 19-21, 1996 in Research Triangle Park near Raleigh, North Carolina, USA.The technical papers presented by the speakers cover a broad range of topics of interest to professionals in the municipal solid waste field. Technical sessions on the following subjects were presented: U.S. Landfill Gas Regulations, Control Technologies, Emission and Migration Control, Landfill Gas Generation Models, Field Practices, Case Studies of Landfill Gas Utilization, Global Methane Control, International Perspectives, and Emerging Technologies and Issues in the field of Landfill Gas Utilization.

  14. Changing face of the landfill

    SciTech Connect

    1995-10-01

    Integrated approach at Oregon landfill diverts wood and yard trimmings, while turning methane into power for 1,800 homes. Opened in the 1940`s as an open burn dump, Coffin Butte has evolved over the years into a sophisticated waste management facility incorporating ambitious recovery programs. While some of this change has been driven by regulatory demands, many of Valley Landfill`s innovations have come in response to market opportunities. Valley Landfill`s Processing and Recovery Center (PRC) is located a half mile down the road from the landfill site. Opened in 1990, the facility recycles urban wood waste, yard trimmings and street sweepings. The heart of this operation is a 500 hp horizontal feed, fixed-hammer grinder. Although this machine is typically used only for wood grinding, PRC was able to adapt it to handle both wood and yard trimmings by installing special feed roll assembly to compress green waste passing over the infeed belt. The facility handles approximately 40,000 cubic yards of loose green material and produces 15,000 to 18,000 yards of compost. The finished product is run through a trommel with a 5/8 inch mesh screen. Most of the compost is sold in bulk to area garden centers. A portion is processed through a 3/8 inch shaker screen and sold to a local company for use in bagged soil products. Valley Landfill is a partner in an ambitious project to generate electricity from landfill biogas.

  15. [Effects of soil covering on solar greenhouse pepper water use efficiency and soil nitrate N and available phosphorus contents].

    PubMed

    Zhou, Mao-juan; Liang, Yin-li; Chen, Jia-rui; Xiong, Ya-mei; Wei, Ze-xiu

    2007-06-01

    A greenhouse study on the effects of soil covering on pepper (Capsicum anmuum L.) water use efficiency and soil nitrate and available phosphorus contents showed that straw mulch + plastic film mulch could get the highest pepper yield water use efficiency (33.04 kg . m(-3)) and economic water use efficiency (50.22 yuan . m(-3)), followed by plastic film mulch, with the two parameters being 18.81 kg . m(-3) and 28.57 yuan . m(-3), respectively. Significant differences of nitrate N content in 0-20 cm soil layer were observed among different treatments. The control had the highest nitrate N content (50.33 mg . kg(-1)), followed by straw mulch (31.98 mg . kg(-1)) and straw + plastic film mulch (31.96 mg . kg(-1)), and plastic film mulch and applying water preserving agent. Compared with the control, soil covering could increase the nitrate N use efficiency of pepper, and decrease the accumulation of nitrate N in plough layer. In 0-20 cm soil layer, treatment plastic film mulch had the lowest available phosphorus content (0.72 mg . kg(-3)), and the second (0. 92 mg . kg(-1)) was the treatment straw + plastic film mulch. Treatments straw + plastic film mulch and plastic film mulch could increase pepper fruit yield and fertilizer use efficiency, and decrease fertilizer loss. PMID:17763748

  16. Modeled Impacts of Cover Crops and Vegetative Barriers on Corn Stover Availability and Soil Quality

    SciTech Connect

    Ian J. Bonner; David J. Muth Jr.; Joshua B. Koch; Douglas L. Karlen

    2014-06-01

    Environmentally benign, economically viable, and socially acceptable agronomic strategies are needed to launch a sustainable lignocellulosic biofuel industry. Our objective was to demonstrate a landscape planning process that can ensure adequate supplies of corn (Zea mays L.) stover feedstock while protecting and improving soil quality. The Landscape Environmental Assessment Framework (LEAF) was used to develop land use strategies that were then scaled up for five U.S. Corn Belt states (Nebraska, Iowa, Illinois, Indiana, and Minnesota) to illustrate the impact that could be achieved. Our results show an annual sustainable stover supply of 194 million Mg without exceeding soil erosion T values or depleting soil organic carbon [i.e., soil conditioning index (SCI)?>?0] when no-till, winter cover crop, and vegetative barriers were incorporated into the landscape. A second, more rigorous conservation target was set to enhance soil quality while sustainably harvesting stover. By requiring erosion to be <1/2 T and the SCI-organic matter (OM) subfactor to be >?0, the annual sustainable quantity of harvestable stover dropped to148 million Mg. Examining removal rates by state and soil resource showed that soil capability class and slope generally determined the effectiveness of the three conservation practices and the resulting sustainable harvest rate. This emphasizes that sustainable biomass harvest must be based on subfield management decisions to ensure soil resources are conserved or enhanced, while providing sufficient biomass feedstock to support the economic growth of bioenergy enterprises.

  17. Evaluation of Soil Manipulation to Prepare Engineered Earthen Waste Covers for Revegetation.

    PubMed

    Waugh, W Joseph; Benson, Craig H; Albright, William H; Smith, Gregory M; Bush, Richard P

    2015-11-01

    Seven ripping treatments designed to improve soil physical conditions for revegetation were compared on a test pad simulating an earthen cover for a waste disposal cell. The field test was part of study of methods to convert compacted-soil waste covers into evapotranspiration covers. The test pad consisted of a compacted layer of fine-textured soil simulating a barrier protection layer overlain by a gravelly sand bedding layer and a cobble armor layer. Treatments included combinations of soil-ripping implements (conventional shank [CS], wing-tipped shank [WTS], and parabolic oscillating shank with wings [POS]), ripping depths, and number of passes. Dimensions, dry density, moisture content, and particle size distribution of disturbance zones were determined in two trenches excavated across rip rows. The goal was to create a root-zone dry density between 1.2 and 1.6 Mg m and a seedbed soil texture ranging from clay loam to sandy loam with low rock content. All treatments created V-shaped disturbance zones as measured on trench faces. Disturbance zone size was most influenced by ripping depth. Winged implements created larger disturbance zones. All treatments lifted fines into the bedding layer, moved gravel and cobble down into the fine-textured protection layer, and thereby disrupted the capillary barrier at the interface. Changes in dry density within disturbance zones were comparable for the CS and WTS treatments but were highly variable among POS treatments. Water content increased in the bedding layer and decreased in the protection layer after ripping. The POS at 1.2-m depth and two passes created the largest zone with a low dry density (1.24 Mg m) and the most favorable seedbed soil texture (gravely silt loam). However, ripping also created large soil aggregates and voids in the protection layer that may produce preferential flow paths and reduce water storage capacity. PMID:26641343

  18. Restoring the biological crust cover of soils across biomes in arid North America

    NASA Astrophysics Data System (ADS)

    Garcia-Pichel, Ferran; Antoninka, Anita; Bowker, Matthew; Giraldo Silva, Ana; Nelson, Corey; Velasco Ayuso, Sergio; Barger, Nichole; Belnap, Jayne; Reed, Sasha; Duniway, Michael

    2015-04-01

    Biological soil crust communities provide important ecosystem services to arid lands, particularly regarding soil fertility and stability against erosion. In North America, and in many other areas of the globe, increasingly intense human activities, ranging from cattle grazing to military training, have resulted in the significant deterioration of biological soil surface cover of soils. With the intent of attaining sustainable land use practices, we are conducting a 5-year, multi-institutional research effort to develop feasible soil crusts restoration strategies for US military lands. We are including field sites of varying climatic regions (warm and cold deserts, in the Chihuahuan Desert and in the Great Basin, respectively) and varying edaphic characteristics (sandy and silty soils in each). We have multiple aims. First, we aim to establishing effective "biocrust nurseries" that produce viable and pedigreed inoculum, as a supply center for biocrust restoration and for research and development. Second, we aim to develop optimal field application methods of biocrust inoculum in a series of field trials. Currently in our second year of research, we will be reporting on significant advances made on optimizing methodologies for the large-scale supply of inoculum based on a) pedigreed laboratory cultures that match the microbial community structure of the original sites, and b) "in soil" biomass enhancement, whereby small amounts of local crusts are nursed under greenhouse conditions to yield hundred-fold increases in biomass without altering significantly community structure. We will also report on field trials for methodologies in field application, which included shading, watering, application of chemical polymers, and soil surface roughening. In a soon-to-be-initiated effort we also aim to evaluate soil and plant responses to biocrust restoration with respect to plant community structure, soil fertility, and soil stability, in multi-factorial field experiments. An important part of the plan will be to construct effective channels for sharing challenges and solutions in biocrust restoration with military and federal land managers.

  19. Emission characteristics and air-surface exchange of gaseous mercury at the largest active landfill in Asia

    NASA Astrophysics Data System (ADS)

    Zhu, Wei; Li, Zhonggen; Chai, Xiaoli; Hao, Yongxia; Lin, Che-Jen; Sommar, Jonas; Feng, Xinbin

    2013-11-01

    The emission characteristics and air-surface exchange of gaseous elemental mercury (GEM) at Laogang landfill in Shanghai, China, the largest active landfill in Asia, has been investigated during two intensive field campaigns in 2011 and 2012. The mercury (Hg) content in municipal solid waste (MSW) varied widely from 0.19 to 1.68 mg kg-1. Over the closed cell in the landfill, the mean ambient air GEM concentration was virtually indistinguishable from the hemispherical background level (1.5-2.0 ng m-3) while the concentration downwind of ongoing landfill operation (e.g. dumping, burying and compacting of MSW) was clearly elevated. GEM emission through landfill gas (LFG) was identified as a significant source. GEM concentrations in LFGs collected from venting pipes installed in different landfill cells varied widely from 3.0 to 1127.8 ng m-3. The GEM concentrations were found negatively correlated to the age of LFG cells, suggesting GEM released through LFG declined readily with time. The GEM emission from this source alone was estimated to be 1.23-1.73 mg h-1. GEM emission from cover soil surfaces was considerably lower and at a scale comparable to that of background soil surfaces. This is in contrast to earlier reports showing enhanced GEM emissions from landfill surfaces in Southern China, probably due to the difference in soil Hg content and gas permeability characteristics of soils at different sites. Vertical concentration profiles of GEM in the interstitial gas of buried MSW were sampled, perhaps for the first time, which exhibited a wide spatial variability (4.9-713.1 ng m-3) in the 3-year-old landfill cell investigated. GEM emission from landfill operation was estimated to be 290-525 mg h-1 using a box model. This suggests that GEM degassing from Laogang landfill is quantitatively largely dominated by emissions from daily landfilling operations with a much smaller contribution from LFG venting and insignificant (bi-directional fluxes near zero) contribution from surfaces capped with a soil layer. This study reveals divergent GEM emission patterns among landfill cells of different ages, and provides essential emission estimates for formulating Hg emission reduction strategies for a large landfill.

  20. The influence of atmospheric pressure on landfill methane emissions

    SciTech Connect

    Czepiel, P.M.; Shorter, J.H.; Mosher, B.; Allwine, E.; McManus, J.B.; Harriss, R.C.; Kolb, C.E.; Lamb, B.K

    2003-07-01

    Landfills are the largest source of anthropogenic methane (CH{sub 4}) emissions to the atmosphere in the United States. However, few measurements of whole landfill CH{sub 4} emissions have been reported. Here, we present the results of a multi-season study of whole landfill CH{sub 4} emissions using atmospheric tracer methods at the Nashua, New Hampshire Municipal landfill in the northeastern United States. The measurement data include 12 individual emission tests, each test consisting of 5-8 plume measurements. Measured emissions were negatively correlated with surface atmospheric pressure and ranged from 7.3 to 26.5 m{sup 3} CH{sub 4} min{sup -1}. A simple regression model of our results was used to calculate an annual emission rate of 8.4x10{sup 6} m{sup 3} CH{sub 4} year{sup -1}. These data, along with CH{sub 4} oxidation estimates based on emitted landfill gas isotopic characteristics and gas collection data, were used to estimate annual CH{sub 4} generation at this landfill. A reported gas collection rate of 7.1x10{sup 6} m{sup 3} CH{sub 4} year{sup -1} and an estimated annual rate of CH{sub 4} oxidation by cover soils of 1.2x10{sup 6} m{sup 3} CH{sub 4} year{sup -1} resulted in a calculated annual CH{sub 4} generation rate of 16.7x10{sup 6} m{sup 3} CH{sub 4} year{sup -1}. These results underscore the necessity of understanding a landfill's dynamic environment before assessing long-term emissions potential.

  1. Fate of glyphosate and degradates in cover crop residues and underlying soil: A laboratory study.

    PubMed

    Cassigneul, A; Benoit, P; Bergheaud, V; Dumeny, V; Etiévant, V; Goubard, Y; Maylin, A; Justes, E; Alletto, L

    2016-03-01

    The increasing use of cover crops (CC) may lead to an increase in glyphosate application for their destruction. Sorption and degradation of (14)C-glyphosate on and within 4 decaying CC-amended soils were compared to its fate in a bare soil. (14)C-Glyphosate and its metabolites distribution between mineralized, water-soluble, NH4OH-soluble and non-extractable fractions was determined at 5 dates during a 20°C/84-d period. The presence of CC extends (14)C-glyphosate degradation half-life from 7 to 28days depending on the CC. (14)C-Glyphosate dissipation occurred mainly through mineralization in soils and through mineralization and bound residue formation in decaying CC. Differences in sorption and degradation levels were attributed to differences in composition and availability to microorganisms. CC- and soil-specific dissipation patterns were established with the help of explicit relationships between extractability and microbial activity. PMID:26760277

  2. Multiple-Year Water Balance of Soil Covers in a Semiarid Setting

    SciTech Connect

    Fayer, Michael J.; Gee, Glendon W.

    2006-03-01

    Surface covers are used to close hazardous and low-level radioactive sites for time frames ranging from hundreds of years to millennia or more. In the absence of data for such durations, the long-term performance of such barriers can only be represented with short-term tests or inferred from analogs and modeling. This paper provides evidence of field performance of soil covers for periods up to 17 years. The results of lysimeter studies from a semi-arid site in Washington State show that a soil cover of 1.5 m of silt loam above a sand/gravel capillary break can eliminate drainage. The results were similar if plants were present or not, demonstrating the robustness of the design. Furthermore, reducing the silt loam thickness to 1.0 m (as might occur via erosion), with or without plants, did not lead to drainage. When irrigated to mimic 3x precipitation conditions, the vegetated Hanford Barrier continued to prevent drainage. Overall, the results showed no diminution in performance during the 17 years of testing. Only when plants were eliminated completely from the 3x precipitation test did drainage occur (rates ranged from 6 to 16 mm/yr). In a separate test, replacing the top 0.2 m of silt loam with dune sand and reducing the plant cover did not lead immediately to the onset of drainage, but soil matric heads within the silt loam noticeably increased. This observation suggests that dune sand migration onto a surface cover has the potential to reduce a covers ability to minimize deep drainage.

  3. Water regime of soils under the different vegetative cover, the Giant Mountains, Czech Republic.

    NASA Astrophysics Data System (ADS)

    Dvorak, I. J.; Tesar, M.; M., Sir; Dohnal, J.

    2009-04-01

    Several monitored plots, located in the Giant Mountains in different positions (valley, slope), are covered by different vegetation (dwarf pine forest, spruce forest, meadow). Soil moisture properties in relation to vegetative cover (dwarf pine versus grassland stands) were studied from the year 2000 to 2006. The main goal was to analyse chosen rainfall-runoff periods with respect to diferent vegetative cover. Every plot was arranged by automatic station for continual soil moisture measurements by VIRRIB sensors (Phase Transmition) in depth of 15 and 45 cm, tensiometer suction presure in depth of 15, 30, 45 and 60 cm and temperature of soil and air. Three plots were also arranged by rain gauges for precipitation measurements in the vegetation season. To complete the characteristics of the unsaturated zone the particle-size analysis and retention curves for depths of 15, 30, 45 and 60 cm were done. Four groups of three rod probes (0.3, 0.6 and 0.9 m) for TDR (Time Domain Reflectometry) soil moisture measurements for seven plots were installed. The irregular measurements were done during 2000, 2001, 2002 and 2003 vegetation seasons. The values of soil moisture for depth intervals of 0-30 cm, 30-60 cm and 60-90 cm were computed for each plot. The TDR values of soil moisture are generally lower than the results obtained from VIRRIB sensors. The explanation of this fact should be that the used TDR measurements involve bigger interval of soil profile than VIRRIB sensors which measure smaller area of soil. The other reason could be the diferent way of probe instalation for each method. The results were compared with the data obtained from VIRRIB sensors, and where possible, the TDR data was used for giving precision to the VIRRIB data. Significant influence of diferent vegetative cover on water regime in soils of tundra area of the Giant Mountains was determined but not sufficiently explained yet. Surprisingly the water regime under the grassland showed similar behavior as a forest area against the dwarf pine stands during the most rainfall-runoff periods studied. The research is supported by the Czech Science Foundation (Projects No. 205/08/1174 and 526/08/1016).

  4. Gas pressure and concentration gradients at the top of a landfill

    SciTech Connect

    Bogner, J.; Vogt, M.; Moore, C.; Gartman, D.

    1987-01-01

    Vertical gas pressure and concentration gradients are being investigated at the Mallard North Landfill (DuPage County, Illinois) using nests of probes installed in the top of refuse and at two depths in the clay cover materials. Soil gas pressures and atmospheric pressure are monitored continuously using electronic pressure transducers linked to a microcomputer. Concentrations of methane, carbon dioxide, nitrogen, and oxygen in the soil gas are determined using a field gas chromatograph. Supporting meteorological, soil temperature, and soil moisture data also are obtained. Based on data from the fall of 1985 and the spring, summer, and fall of 1986, soil gas pressures at all depths responded to changes in barometric pressure; however, the type of response varied, depending on soil moisture and temperature. During warm, dry weather, for example, soil gas pressures in the cover and the top of the refuse equilibrate rapidly with barometric pressure, indicating that diffusion is the major mechanism for gas transport at that time (no pressure gradients). The rate of diffusional flow depends on the properties of the cover materials, as well as the concentration gradients. Increases in soil moisture, in particular, decrease the gas-filled porosity of the cover materials and retard gas movement. Our results suggest that design and maintenance of tighter landfill covers should be considered at sites where gas recovery is anticipated, to prevent loss of methane and influx of oxygen.

  5. Factors influencing the establishment of floristically rich grasslands on a restored landfill site

    SciTech Connect

    Ireland, E.M.

    1991-01-01

    Natural revegetation on landfill sites often results in a species poor sward dominated by Elymus repens (Shaw, 1983; Davis, 1988; Wong, 1988). The aim of this study was primarily to investigate the mechanism by which E.repens achieved such apparent domination and secondly to investigate various methods to establish floristically rich grasslands on a restored landfill site. Low rates of germination and survival were recorded from seeds of Plantago lanceolata, Centaureau nigrand Leucanthemum vulgare sown into a sward of E.repens on a restored landfill site in Essex, even during periods with adequate soil water. Plants of P.lanceolata, C.nigra and L. vulgare were grown in pots and transplanted into the sward of E.repens. Over the following two years a significant decrease in crown cover of these species was recorded. In areas where E.repens had been treated with herbicide or mown, seedlings and introduced plants of P.lanceolata, C.nigra and L.vulgare increased in cover over two years. Stomatal conductance of P.lanceolata, C.nigra and L.vulgare was reduced when these species were growing with E.repens even during periods with adequate soil water. P.lanceolata, C.nigra and L.vulgare growing with E.repens on restored landfill has been shown experimentally to result in reduced cover. It is suggested that this is due to competition in combination potentially, with allelochemical effects of E.repens. Successful establishment of a floristically rich grass mix was achieved by the reduction in cover of E.repens by herbicide or mowing. On newly restored landfill a careful balance between soil treatments, fertilizer levels and subsequent management in the form of mowing must be attained in order to establish floristically rich grasslands. The results from this study show that by utilizing various management techniques a floristically rich grass mix could be established on a restored landfill site.

  6. Interaction effects of climate and land use/land cover change on soil organic carbon sequestration.

    PubMed

    Xiong, Xiong; Grunwald, Sabine; Myers, D Brenton; Ross, C Wade; Harris, Willie G; Comerford, Nicolas B

    2014-09-15

    Historically, Florida soils stored the largest amount of soil organic carbon (SOC) among the conterminous U.S. states (2.26 Pg). This region experienced rapid land use/land cover (LULC) shifts and climate change in the past decades. The effects of these changes on SOC sequestration are unknown. The objectives of this study were to 1) investigate the change in SOC stocks in Florida to determine if soils have acted as a net sink or net source for carbon (C) over the past four decades and 2) identify the concomitant effects of LULC, LULC change, and climate on the SOC change. A total of 1080 sites were sampled in the topsoil (0-20 cm) between 2008 and 2009 representing the current SOC stocks, 194 of which were selected to collocate with historical sites (n = 1251) from the Florida Soil Characterization Database (1965-1996) for direct comparison. Results show that SOC stocks significantly differed among LULC classes--sugarcane and wetland contained the highest SOC, followed by improved pasture, urban, mesic upland forest, rangeland, and pineland while crop, citrus and xeric upland forest remained the lowest. The surface 20 cm soils acted as a net sink for C with the median SOC significantly increasing from 2.69 to 3.40 kg m(-2) over the past decades. The SOC sequestration rate was LULC dependent and controlled by climate factors interacting with LULC. Higher temperature tended to accelerate SOC accumulation, while higher precipitation reduced the SOC sequestration rate. Land use/land cover change observed over the past four decades also favored the C sequestration in soils due to the increase in the C-rich wetland area by ~140% and decrease in the C-poor agricultural area by ~20%. Soils are likely to provide a substantial soil C sink considering the climate and LULC projections for this region. PMID:25010945

  7. Case studies in alternative landfill design

    SciTech Connect

    Barbagallo, J.C.; Druback, G.W.

    1995-12-31

    In the past, landfills or {open_quotes}dumps{close_quotes} were not highly regulated and typically did not require a detailed engineering design. However, landfills are no longer just holes in the ground, and landfill closures entail more than just spreading some dirt on top of piles of garbage. Today landfill design is a highly regulated, complex design effort that integrates soils and geosynthetics into systems aimed at providing long-term protection for the environment and surrounding communities. Integrating these complex design systems into the available landscape and exising landfill configuration often requires the designer go beyond the {open_quotes}typical{close_quotes} landfill and landfill closure design to satisfy regulations and provide cost-effective solutions.

  8. Molecular characterization of fungal communities in non-tilled, cover-cropped upland rice field soils.

    PubMed

    Nishizawa, Tomoyasu; Zhaorigetu; Komatsuzaki, Masakazu; Sato, Yoshinori; Kaneko, Nobuhiro; Ohta, Hiroyuki

    2010-01-01

    This study aimed to characterize soil fungal communities in upland rice fields managed with tillage/non-tillage and winter cover-cropping (hairy vetch and cereal rye) practices, using PCR-based molecular methods. The study plots were maintained as upland fields for 5 years and the soils sampled in the second and fifth years were analyzed using T-RFLP (terminal restriction fragment length polymorphism) profiling and clone libraries with the internal transcribed spacer (ITS) region and domain 1 (D1) of the fungal large-subunit (fLSU) rRNA (D1(fLSU)) as the target DNA sequence. From the 2nd-year-sample, 372 cloned sequences of fungal ITS-D1(fLSU) were obtained and clustered into 80 nonredundant fungal OTUs (operational taxonomic units) in 4 fungal phyla. The T-RFLP profiling was performed with the 2nd- and 5th-year-samples and the major T-RFs (terminal restriction fragments) were identified using a theoretical fragment analysis of the ITS-D1(fLSU) clones. These molecular analyses showed that the fungal community was influenced more strongly by the cover-cropping than tillage practices. Moreover, the non-tilled, cover-cropped soil was characterized by a predominance of Cryptococcus sp. in the phylum Basidiomycota. We provided a genetic database of the fungal ITS-D1(fLSU)s in the differently managed soils of upland rice fields. PMID:21597240

  9. Land agroecological quality assessment in conditions of high spatial soil cover variability at the Pereslavskoye Opolye.

    NASA Astrophysics Data System (ADS)

    Morev, Dmitriy; Vasenev, Ivan

    2015-04-01

    The essential spatial variability is mutual feature for most natural and man-changed soils at the Central region of European territory of Russia. The original spatial heterogeneity of forest soils has been further complicated by a specific land-use history and human impacts. For demand-driven land-use planning and decision making the quantitative analysis and agroecological interpretation of representative soil cover spatial variability is an important and challenging task that receives increasing attention from private companies, governmental and environmental bodies. Pereslavskoye Opolye is traditionally actively used in agriculture due to dominated high-quality cultivated soddy-podzoluvisols which are relatively reached in organic matter (especially for conditions of the North part at the European territory of Russia). However, the soil cover patterns are often very complicated even within the field that significantly influences on crop yield variability and have to be considered in farming system development and land agroecological quality evaluation. The detailed investigations of soil regimes and mapping of the winter rye yield have been carried in conditions of two representative fields with slopes sharply contrasted both in aspects and degrees. Rye biological productivity and weed infestation have been measured in elementary plots of 0.25 m2 with the following analysis the quality of the yield. In the same plot soil temperature and moisture have been measured by portable devices. Soil sampling was provided from three upper layers by drilling. The results of ray yield detailed mapping shown high differences both in average values and within-field variability on different slopes. In case of low-gradient slope (field 1) there is variability of ray yield from 39.4 to 44.8 dt/ha. In case of expressed slope (field 2) the same species of winter rye grown with the same technology has essentially lower yield and within-field variability from 20 to 29.6 dt/ha. The variability in crop yield between two fields is determined by their differences in mesorelief, A-horizon average thickness and slightly changes in soil temperature. The within-field crop yield variability is determined by microrelief and connected differences in soil moisture. Higher soil cover variability reflects in higher variability of winter ray yield and its quality that could be predicted and planed in conditions of concrete field and year according to principal limiting factors evaluation.

  10. Spreading Topsoil Encourages Ecological Restoration on Embankments: Soil Fertility, Microbial Activity and Vegetation Cover

    PubMed Central

    Rivera, Desire; Mejas, Violeta; Juregui, Berta M.; Lpez-Archilla, Ana Isabel; Peco, Begoa

    2014-01-01

    The construction of linear transport infrastructure has severe effects on ecosystem functions and properties, and the restoration of the associated roadslopes contributes to reduce its impact. This restoration is usually approached from the perspective of plant cover regeneration, ignoring plant-soil interactions and the consequences for plant growth. The addition of a 30 cm layer of topsoil is a common practice in roadslope restoration projects to increase vegetation recovery. However topsoil is a scarce resource. This study assesses the effects of topsoil spreading and its depth (10 to 30 cm) on two surrogates of microbial activity (?-glucosidase and phosphatase enzymes activity and soil respiration), and on plant cover, plant species richness and floristic composition of embankment vegetation. The study also evaluates the differences in selected physic-chemical properties related to soil fertility between topsoil and the original embankment substrate. Topsoil was found to have higher values of organic matter (11%), nitrogen (44%), assimilable phosphorous (50%) and silt content (54%) than the original embankment substrate. The topsoil spreading treatment increased microbial activity, and its application increased ?-glucosidase activity (45%), phosphatase activity (57%) and soil respiration (60%). Depth seemed to affect soil respiration, ?-glucosidase and phosphatase activity. Topsoil application also enhanced the species richness of restored embankments in relation to controls. Nevertheless, the depth of the spread topsoil did not significantly affect the resulting plant cover, species richness or floristic composition, suggesting that both depths could have similar effects on short-term recovery of the vegetation cover. A significant implication of these results is that it permits the application of thinner topsoil layers, with major savings in this scarce resource during the subsequent slope restoration work, but the quality of topsoil relative to the original substrate should be previously assessed on a site by site basis. PMID:24984137

  11. Spreading topsoil encourages ecological restoration on embankments: soil fertility, microbial activity and vegetation cover.

    PubMed

    Rivera, Desire; Mejas, Violeta; Juregui, Berta M; Costa-Tenorio, Marga; Lpez-Archilla, Ana Isabel; Peco, Begoa

    2014-01-01

    The construction of linear transport infrastructure has severe effects on ecosystem functions and properties, and the restoration of the associated roadslopes contributes to reduce its impact. This restoration is usually approached from the perspective of plant cover regeneration, ignoring plant-soil interactions and the consequences for plant growth. The addition of a 30 cm layer of topsoil is a common practice in roadslope restoration projects to increase vegetation recovery. However topsoil is a scarce resource. This study assesses the effects of topsoil spreading and its depth (10 to 30 cm) on two surrogates of microbial activity (?-glucosidase and phosphatase enzymes activity and soil respiration), and on plant cover, plant species richness and floristic composition of embankment vegetation. The study also evaluates the differences in selected physic-chemical properties related to soil fertility between topsoil and the original embankment substrate. Topsoil was found to have higher values of organic matter (11%), nitrogen (44%), assimilable phosphorous (50%) and silt content (54%) than the original embankment substrate. The topsoil spreading treatment increased microbial activity, and its application increased ?-glucosidase activity (45%), phosphatase activity (57%) and soil respiration (60%). Depth seemed to affect soil respiration, ?-glucosidase and phosphatase activity. Topsoil application also enhanced the species richness of restored embankments in relation to controls. Nevertheless, the depth of the spread topsoil did not significantly affect the resulting plant cover, species richness or floristic composition, suggesting that both depths could have similar effects on short-term recovery of the vegetation cover. A significant implication of these results is that it permits the application of thinner topsoil layers, with major savings in this scarce resource during the subsequent slope restoration work, but the quality of topsoil relative to the original substrate should be previously assessed on a site by site basis. PMID:24984137

  12. Frequent fire promotes diversity and cover of biological soil crusts in a derived temperate grassland.

    PubMed

    O'Bryan, Katharine E; Prober, Suzanne Mary; Lunt, Ian D; Eldridge, David J

    2009-04-01

    The intermediate disturbance hypothesis (IDH) predicts that species diversity is maximized at moderate disturbance levels. This model is often applied to grassy ecosystems, where disturbance can be important for maintaining vascular plant composition and diversity. However, effects of disturbance type and frequency on cover and diversity of non-vascular plants comprising biological soil crusts are poorly known, despite their potentially important role in ecosystem function. We established replicated disturbance regimes of different type (fire vs. mowing) and frequency (2, 4, 8 yearly and unburnt) in a high-quality, representative Themeda australis-Poa sieberiana derived grassland in south-eastern Australia. Effects on soil crust bryophytes and lichens (hereafter cryptogams) were measured after 12 years. Consistent with expectations under IDH, cryptogam richness and abundance declined under no disturbance, likely due to competitive exclusion by vascular plants as well as high soil turnover by soil invertebrates beneath thick grass. Disturbance type was also significant, with burning enhancing richness and abundance more than mowing. Contrary to expectations, however, cryptogam richness increased most dramatically under our most frequent and recent (2 year) burning regime, even when changes in abundance were accounted for by rarefaction analysis. Thus, from the perspective of cryptogams, 2-year burning was not an adequately severe disturbance regime to reduce diversity, highlighting the difficulty associated with expression of disturbance gradients in the application of IDH. Indeed, significant correlations with grassland structure suggest that cryptogam abundance and diversity in this relatively mesic (600 mm annual rainfall) grassland is maximised by frequent fires that reduce vegetation and litter cover, providing light, open areas and stable soil surfaces for colonisation. This contrasts with detrimental effects of 2-year burning on native perennial grasses, indicating that this proliferation of cryptogams has potentially high functional significance for situations where vegetation cover is depleted, particularly for reducing soil erosion. PMID:19132400

  13. High retention of N P nutrients, soil organic carbon, and fine particles by cover crops under tropical climate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cover cropping system has shown a potential to improve soil quality and carbon sequestration but the residue decomposition rates determined by biotic and abiotic factors play a crucial role to reach such objectives. Legume and non-legume cover crop residues were applied to the surface of two soils i...

  14. Interactions between allelochemicals and the microbial community affect weed suppresion following cover crop residue incorporation into soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of this study is to understand how soil microorganisms interact with cover crop-derived allelochemicals to suppress weed germination and growth following cover crop residue incorporation. We conducted a time series experiment by crossing sterilized and non-sterilized soil with four dif...

  15. The effect of surface cover and soil devastation on infiltration rate in steep forest plantations

    NASA Astrophysics Data System (ADS)

    Onda, Y.; Hiraoka, M.; Kato, H.; Gomi, T.; Miyata, S.; Mizugaki, S.

    2008-12-01

    The Japanese cypress (Hinoki; Chamaecyparis obtusa) is a major commercial tree species in Japan, and without thinning of high-density stands, canopy closure prevents development of understory vegetation. Therefore there is a concern for overlandflow and sediment yield due to infiltration rate lowering. We developed a light-weight rainfall simulator based on the design of Meyer and Harmon (1979). A flat fan Veejet 80150 spraying nozzle (Spraying systems Co., USA) is mounted on the manifold at 2.13 m high from the plot surface. The nozzle oscillates so that the spray fan sweeps across the targeting 1 m x 1 m plot. The Veejet 80150 spraying nozzle produces large raindrops larger than 2 mm in diameter, and can simulate the high raindrop kinetic energy of natural throughfall. A targeted rainfall rate is 180 mm/h. About 30 sprinkling experiments have been conducted on 35-degree hillslopes with varying surface cover in 5 locations in Japan. We obtained the minimum infiltration rate of 14 mm/h where the surface cover is very little. The infiltration rates were plotted against the total understory vegetation and dry weight of total surface cover including litter. The infiltration rate increased with the increasing total surface cover, and generally higher regression coefficient was found for the case of the total surface cover. In some cases, high infiltration rates were obtained where surface cover is low. Two possible explanations can be made; 1) surface soil (especially fine particles) has been washed away, where soil is mostly composed of gravel and the percentage of fine fraction is low, or 2) because of long-term soil loss by raindrop detachment, remaining soil looks like "ghanging"h between exposed fine root networks of Japanese cypress, where soil bulk density is significantly lower than other site. Therefore the infiltration rate in the devastated Japanese cypress plantations is not only controlled by loss of surface vegetation by low light condition, but soil devastation through long-term erosion history would also control the infiltration rate and then geomorphic processes.

  16. Response of tomato plants to simulated landfill gas mixtures

    SciTech Connect

    Arthur, J.J.; Leone, I.A.; Flower, F.B.

    1985-01-01

    The roots of tomato plants were fumigated with simulated refuse-generated gas mixtures at levels of methane (CH/sub 4/), carbon dioxide (CO/sub 2/), and oxygen (O/sub 2/) previously measured in the atmospheres of landfill cover soils associated with poor growth or death of plants. A concentration of 18% CO/sub 2/ or greater, exceeded in almost 30% of thirty-two landfills examined throughout the US, caused reduced growth and visible symptoms on tomato after 1 wk, regardless of O/sub 2/ level. Doubling the CO/sub 2/ level to that encountered in a typical local site (Edgeboro Landfill) resulted in more severe symptom development and the subsequent death of plants. Methane, in concentrations of 20% and above, found in more than 25% of the landfills visited, while not observed to be toxic per se; was associated with drastic O/sub 2/ depletion in the soil atmosphere, which activity was believed to be the cause of the plant decline.

  17. Soil wetting processes at high temporal resolution in a semiarid mediterranean watershed with scattered tree cover

    NASA Astrophysics Data System (ADS)

    Lozano-Parra, Javier; van Schaik, Loes; Schnabel, Susanne; Gómez-Gutiérrez, Álvaro

    2015-04-01

    Soil wetting processes play a key role for the distribution of water and solutes and thereby for the water availability for plants. However, characterization of such processes (from slower to faster flows), frequency of occurrence, and factors that cause them, are still poorly known. This characterization is important in hydrological studies because enables a better understanding of spatio-temporal variability of water resources and allows improving the design of models. Using a method based on the maximal soil water increase registered by a sensor over a minimum given time interval during a rainfall event, types of soil wetting processes were classified and quantified. For this, capacitance sensors which registered the volumetric water content at high temporal resolution (30-min) along of more than two hydrological years (mainly for 2010-2011 and 2011-2012), were installed in soil profiles at 5, 15 cm, and 5 cm above the bedrock and depending on soil depth. This distribution along the soil profile is justified because soils are generally very shallow and most of the roots are concentrated in the upper layer. The sensors were gathered in 9 soil moisture stations characterized by lithology, topographic position, as well as by different vegetation covers: under tree canopy, under shrub, and in open spaces or grasslands. Besides, the data mining technique Multivariate Adaptive Regression Spline (MARS) was used to identify and rank the factors influencing flow types as well as modelling their occurrence. The work was carried out in an experimental catchment of the Spanish region of Extremadura. Results indicated that there is a general behavior or pattern of soil moisture dynamics in the catchment with a dominant occurrence of slower soil wetting processes (>50%), which may be considered as matrix flows, and a low occurrence of those faster processes (<30%), considered as preferential flows. Nevertheless, when the total volume of water is considered then preferential flow becomes the dominant process, so that the ecological role of both flow types becomes prominent in water-limited environments. Statistical multivariate analyses based on data-mining techniques proved that although both flow types depend on variables associated with precipitation and antecedent soil moisture conditions, faster soil wetting processes are mainly related to variables as rainfall intensity and topography, while slower soil wetting processes are related to soils or vegetation.

  18. Spatiotemporal patterns of soil CO2 efflux in drylands are modulated by the type of cover: The role of biocrusts

    NASA Astrophysics Data System (ADS)

    Chamizo, Sonia; Sánchez-Cañete, Enrique P.; Cantón, Yolanda; Rodríguez-Caballero, Emilio; Oyonarte, Cecilio; Domingo, Francisco

    2015-04-01

    Although the quantification of carbon (C) flux dynamics in arid and semiarid ecosystems has acquired relevant interest, it is recognized that C fluxes of drylands have been poorly measured and modeled, despite these regions represent 40% of the Earth land's surface and are known to play a crucial role in the global C cycle. Scarce vegetation and heterogeneity of non vegetated areas contributes to significant uncertainty in evaluating the roles of these ecosystems in C fluxes. In addition, interplant soils in most arid and semiarid areas are covered by biocrusts (communities of cyanobacteria, algae, lichens and mosses in association with soil particles) which strongly affect C uptake and release and also contribute to increasing uncertainty in the assessment of C balance in these ecosystems. A better understanding of CO2 efflux in different soil covers and how they are regulated by environmental factors is necessary for identifying the relationships between C sinks and sources of arid and semiarid ecosystems. Our goal was to analyse temporal dynamics of soil CO2 on representative cover types of semiarid ecosystems (soil under plant, biocrusts and bare soil) and the influence of environmental factors (soil moisture and temperature) on soil CO2 patterns. The study area chosen was a badlands site (El Cautivo, Almería, SE Spain) where biocrusts occupy up to 50% of soil surface. Soil CO2 molar fraction (χc) was continuously monitored using small solid-state CO2 sensors (GM222, Vaisala, Helsinki, Finland) buried at 5 cm under the different covers, during one year. Soil temperature and soil moisture were also measured under these covers. From the CO2 time-series measured, we calculated soil CO2 efflux (Fs) from the 0-5 cm soil profile using Fick's law of diffusion. Our results demonstrate that soil moisture was the main factor driving soil χc. During summer, when soil was dry, all cover types showed similar soil χc. Following a rain, there was a rapid increase in soil χc in all cover types but marked differences were found among them: soil under plant reached the highest values, while in the interplant soil, soils covered by biocrusts showed up to 2 times greater soil χc than bare soils. Soil χc also varied depending on the type of biocrust, with higher values under lichen than cyanobacteria biocrusts, attributed to higher organic matter content and higher abundance and diversity of microfauna under more developed than less developed biocrusts. At daily scale, there was a positive relationship between soil χc and soil temperature. Positive values of Fs (CO2 emissions) were frequently found after rain. Fs was higher in soil under plant (up to 2 µmol m-2 s-1), followed by soil covered by lichens and the lowest in soils covered by cyanobacteria and bare soils (~0.5 µmol m-2 s-1). Our results demonstrate the high spatial variability in CO2 efflux in arid and semiarid areas and the need to consider the contributions of the different representative ground covers to improve C quantification and to make more accurate predictions of the effects of climate change in arid and semiarid regions.

  19. Environmental impact assessment on the construction and operation of municipal solid waste sanitary landfills in developing countries: China case study.

    PubMed

    Yang, Na; Damgaard, Anders; Lü, Fan; Shao, Li-Ming; Brogaard, Line Kai-Sørensen; He, Pin-Jing

    2014-05-01

    An inventory of material and energy consumption during the construction and operation (C&O) of a typical sanitary landfill site in China was calculated based on Chinese industrial standards for landfill management and design reports. The environmental impacts of landfill C&O were evaluated through life cycle assessment (LCA). The amounts of materials and energy used during this type of undertaking in China are comparable to those in developed countries, except that the consumption of concrete and asphalt is significantly higher in China. A comparison of the normalized impact potential between landfill C&O and the total landfilling technology implies that the contribution of C&O to overall landfill emissions is not negligible. The non-toxic impacts induced by C&O can be attributed mainly to the consumption of diesel used for daily operation, while the toxic impacts are primarily due to the use of mineral materials. To test the influences of different landfill C&O approaches on environmental impacts, six baseline alternatives were assessed through sensitivity analysis. If geomembranes and geonets were utilized to replace daily and intermediate soil covers and gravel drainage systems, respectively, the environmental burdens of C&O could be mitigated by between 2% and 27%. During the LCA of landfill C&O, the research scope or system boundary has to be declared when referring to material consumption values taken from the literature; for example, the misapplication of data could lead to an underestimation of diesel consumption by 60-80%. PMID:24656422

  20. Remote sensing as a source of land cover information utilized in the universal soil loss equation

    NASA Technical Reports Server (NTRS)

    Morris-Jones, D. R.; Morgan, K. M.; Kiefer, R. W.; Scarpace, F. L.

    1979-01-01

    In this study, methods for gathering the land use/land cover information required by the USLE were investigated with medium altitude, multi-date color and color infrared 70-mm positive transparencies using human and computer-based interpretation techniques. Successful results, which compare favorably with traditional field study methods, were obtained within the test site watershed with airphoto data sources and human airphoto interpretation techniques. Computer-based interpretation techniques were not capable of identifying soil conservation practices but were successful to varying degrees in gathering other types of desired land use/land cover information.

  1. Unsaturated hydrologic flow parameters based on laboratory and field data for soils near the mixed waste landfill, technical area III, Sandia National Laboratories/New Mexico

    SciTech Connect

    Roepke, C.S.; Strong, W.R.; Nguyen, H.A.

    1996-08-01

    This report presents the results of laboratory tests conducted on soil core samples obtained prior to an instantaneous profile test conducted west of the Mixed Waste Landfill in Technical Area III. The instantaneous profile test was conducted to measure in situ hydrologic parameters controlling unsaturated flow and contaminant transport in the near - surface vadose zone. Soil core samples from the instantaneous profile test plot were tested in the Sandia National Laboratory`s Environmental Restoration Project Hydrology Laboratory to measure saturated hydraulic conductivity and the relationships between moisture content and soil water tension. Data from laboratory tests and the instantaneous profile field test were then modeled using the computer code RETC to quantify moisture content, soil water tension, and unsaturated hydraulic conductivity relationships. Results content, soil verified that a combination of laboratory and field data yielded a more complete definition of hydrologic properties than either laboratory or field data alone. Results also indicated that at native moisture contents, the potential for significant unsaturated aqueous flow is limited, while at saturated or near - saturated conditions, preferential flow may occur.

  2. Spatial and temporal variability of grass cover in two olive grove catchments on contrasting soil types

    NASA Astrophysics Data System (ADS)

    Aguilera, Laura; Taguas, Encarnación V.; Gimeno, Enrique; Gómez, José A.

    2013-04-01

    Mediterranean climate conditions -characterized by the concentration of the precipitation in the seasons of autumn and spring, the low temperatures in winter and extremely warm and dry summers- determine that ground cover by adventitious (or cover crop) vegetation shows significant seasonal and annual variability. In addition, its spatial variability associates also, partially, to water availability among the landscape. This is especially relevant in olive orchards, an agricultural system under high erosion risk in the region where the establishment of herbaceous cover has proved to improve soil protection reducing erosion risk, as well as the improvement of soil properties (Gómez et al., 2009). All these benefits are based on small scale studies where full ground cover by the cover crop is relatively easy to obtain. However, few information is available about the actual ground cover achieved at farm scale, although preliminary observations suggests that this might be extremely variable (Gómez and Giráldez, 2009). This study presents the preliminary results evaluating the spatial and temporal evolution of ground cover by adventitious vegetation (the preferred option by farmers to achieve a cover crop) in two commercial olive farms during 2 hydrological years (2011-2012). The study was conducted in two farms located in the province of Cordoba, Southern Spain. Both were olive orchards grown under deficit irrigation systems and present a gauge station where rainfall, runoff and sediment loads have been measured from the year 2005. The soil management in "La Conchuela" farm was based in the use of herbicide in the line of olive trees to keep the bare soil all year round, and the application of selective herbicide in the lane between the olive trees to promote the grown of graminaceae grasses . In addition, the grass is mechanically killed in June. In the another farm, "Arroyo Blanco", the grass spontaneous cover is allowed until mid-spring in which is also mechanically killed by several tractor passes. Ground cover was evaluated by a field surveys (4 per year) in which the same areas were measured at an approximate density of 4 samples/ha. In each point, over a 0.25 m2 area ground cover was measured using photographs, then point measurements were interpolated using method of Inverse Distance Weighting methods, to generate continuous distribution maps. The spatial and temporal evolution of ground cover in both farms presented a notably different patterns in both farms. In "La Conchuela", maximum values of cover can be reached in winter (61%, Dec-2011) while in "Arroyo Blanco", the maximum values were observed during the spring (50% May-2011) and are dramatically lower in the seasons of summer and autumn. These differences are justified by the influence of the management, the precipitation regime and the soil qualities such as the depth. On the other hand, the large spatial variability of ground cover measurements in both catchments, with coefficients of variation between 41 and 167%, was mainly led by the topography. In both farms the highest values of ground cover were found in those areas with deeper soils located in also in converging areas where surface runoff is concentrated. In the highest and shallowest area, soil management operations might improve the establishment of the vegetation as well as to address the growing in the most erosive periods. Finally, the impact of grass cover on the hydrological and erosive responses in the catchment is also discussed. References Aguilera, L. 2012. Estudio de cubiertas vegetales para el control de la erosión en olivar. Evaluación espacio-temporal en dos fincas comerciales, y exploración de nuevas opciones de cubiertas. Master Thesis. University of Cordoba. Gómez, J.A., Giráldez, J.V. Erosión y degradación de suelos. In: Sostenibilidad de la producción de olivar en Andalucía. Gómez, J.A. (Editor). Junta de Andalucía. Sevilla, p. 45-86. Gómez, J.A., Sobrinho, T.A., Giráldez, J.V., Fereres, E. 2009. Soil management effects on runoff, erosion and soil properties in an olive grove of Southern Spain. Soil and TillageResearch 102: 5 - 13.

  3. Improvement of remote sensing of crop residue cover by accounting for green vegetation and soil spectral properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Conservation tillage methods are beneficial as they disturb soil less and leaves increased crop residue cover (CRC) after planting on the soil surface. CRC helps reduce soil erosion, evaporation, and the need for tillage operations in fields. Greenhouse gas emissions are reduced to due to less fos...

  4. [Succession-driven transformation of plant and soil cover on solifluction sites in the permafrost zone of central Evenkia].

    PubMed

    Prokushkin, S G; Bugaenko, T N; Prokushkin, A S; Shkikunov, V G

    2010-01-01

    The impact of solifluction (soil-sliding) on soil and vegetation cover as well as their restoration during the period after the disturbance was analyzed in the continuous permafrost region of Central Siberia (Central Evenkia). The role of vegetation invading after a disturbance is demonstrated for accumulation of biogenic elements and soil development. PMID:20238469

  5. Applications of remote sensing and GIS in surface hydrology: Snow cover, soil moisture and precipitation

    NASA Astrophysics Data System (ADS)

    Wang, Xianwei

    Studies on surface hydrology can generally be classified into two categories, observation for different components of surface water, and modeling their dynamic movements. This study only focuses on observation part of surface water components: snow cover, soil moisture, and precipitation. Moreover, instead of discussion on the detailed algorithm and instrument technique behind each component, this dissertation pours efforts on analysis of the standard remotely sensed products and their applications under different settings. First in Chapter 2, validation of MODIS Terra 8-day maximum snow cover composite (MOD10A2) in the Northern Xinjiang, China, from 2000-2006, shows that the 8-day MODIS/Terra product has high agreements with in situ measurements as the in situ snow depth is larger or equal to 4 cm, while the agreement is low for the patchy snow as the in situ snow depth less than 4 cm. According to the in situ observation, this chapter develops an empirical algorithm to separate the cloud-covered pixels into snow and no snow. Continued long-term production of MODIS-type snow cover product is critical to assess water resources of the study area, as well as other larger scale global environment monitoring. Terra and Aqua satellites carry the same MODIS instrument and provide two parallel MODIS daily snow cover products at different time (local time 10:30 am and 1:30 pm, respectively). Chapter 3 develops an algorithm and automated scripts to combine the daily MODIS Terra (MOD10A1) and Aqua (MYD10A1) snow cover products, and to automatically generate multi-day Terra-Aqua snow cover image composites, with flexible starting and ending dates and a user-defined cloud cover threshold. Chapter 4 systematically compares the difference between MODIS Terra and Aqua snow cover products within a hydrologic year of 2003-2004, validates the MODIS Terra and Aqua snow cover products using in situ measurements in Northern Xinjiang, and compares the accuracy among the standard MODIS Terra and Aqua snow cover products, and the new combined daily and multi-day composite from both MODIS Terra and Aqua daily products. In Chapter 5, utilizing the new cloud-low multi-day composite of MODIS Terra and Aqua snow cover products, several new methods are developed to study the spatiotemporal variation of snow cover conditions from different aspects at the Northern Xinjiang and on the Central Tianshan Mountains, mainly in China, partly covering Kazakhstan and Kyrgyzstan. Secondly, Chapter 6 investigates the feasibility to indirectly map root-zone soil moisture using optical remote sensing techniques and in situ measurements. Specifically, covariation of root-zone soil moisture with the normalized difference of vegetation index (NDVI) from MODIS observation is studied at three sites (New Mexico, Arizona, and Texas). The three sites represent two types of vegetation (shrub and grass) and two types of climate conditions: arid/semi-arid (New Mexico and Arizona) and humid (Texas). Results show that the root-zone soil moisture has significant linear correlation with vegetation (NDVI). Finally, Chapter 7 validates and compares the NEXRAD Stage III and MPE precipitation products using a high density rain gauge network on the Upper Guadalupe River Basin of the Texas Hill Country in 2001 and 2004. (Abstract shortened by UMI.)

  6. The impact of pan-Arctic snow cover recession on frozen soil heat content

    NASA Astrophysics Data System (ADS)

    Shi, X.; Lettenmaier, D. P.

    2012-12-01

    Warming of the land surface at high latitudes has attracted considerable scientific attention, in part due to the potential for releases of carbon to the atmosphere at warmer temperatures. As an indicator of changes in the land surface energy budget, soil heat content (SHC) arguably provides a more complete understanding of high latitude surface warming than do soil temperatures, which are influenced by surface air temperature (SAT) as well as snow cover extent (SCE). Using the Variable Infiltration Capacity (VIC) land surface model forced with gridded climate observations, we are able to reproduce observed spatial and temporal variations of SCE and SHC over the pan-Arctic land region over the last half-century. On the basis of the SCE trends derived from NOAA satellite observations in 5° latitude bands from April through June for the period 1972-2006, we define a snow covered sensitivity zone (SCSZ), as well as a snow covered non-sensitivity zone (SCNZ) and a non-snow covered zone (NSCZ) for North America and Eurasia. In order to assess the impact of pan-Arctic snow cover changes and further identify the relative roles of snow cover recession and increasing SAT on changes in SHC, we explore long-term trends in SHC, SCE, and SAT and their corresponding correlations in NSCZ, SCSZ and SCNZ for both North America and Eurasia. We find that SHC changes in North America during late spring and early summer are dominated by snow cover recession rather than increasing SAT, whereas over Eurasia from April through June, SAT has the greatest influence and reduced SCE plays a secondary role in the changes of SHC, which mainly result from increased SAT during the summer of the previous year.

  7. Seismic analysis of Industrial Waste Landfill 4 at Y-12 Plant

    SciTech Connect

    1995-04-07

    This calculation was to seismically evaluate Landfill IV at Y-12 as required by Tennessee Rule 1200-1-7-04(2) for seismic impact zones. The calculation verifies that the landfill meets the seismic requirements of the Tennessee Division of Solid Waste, ``Earthquake Evaluation Guidance Document.`` The theoretical displacements of 0.17 in. and 0.13 in. for the design basis earthquake are well below the limiting seimsic slope stability design criteria. There is no potential for liquefaction due to absence of chohesionless soils, or for loss or reduction of shear strength for the clays at this site as result of earthquake vibration. The vegetative cover on slopes will most likely be displaced and move during a large seismic event, but this is not considered a serious deficiency because the cover is not involved in the structural stability of the landfill and there would be no release of waste to the environment.

  8. A field-validated model for landfill methane emissions inclusive of seasonal methane oxidation

    NASA Astrophysics Data System (ADS)

    Bogner, J. E.; Spokas, K.; Chanton, J.

    2010-12-01

    In addition to natural wetlands, atmospheric methane (CH4) has multiple anthropogenic sources with high uncertainties, including rice production, ruminant animals, natural gas leakages, biomass burning, and landfills. For an improved IPCC Tier III methodology for landfill CH4 emissions in California, we have developed a new science-based, field-validated inventory model which decouples emissions from a historical reliance on a theoretical first order kinetic model for CH4 generation potential. The model (CALMIM, CAlifornia Landfill Methane Inventory Model) is a freely-available JAVA tool which estimates net CH4 emissions to the atmosphere for any landfill cover soil over a typical annual cycle, including (1) the effect of engineered gas extraction; (2) the physical effects of daily, intermediate, and final cover materials to retard emissions; and (3) seasonal soil moisture and temperature effects on both gaseous transport and methanotrophic CH4 oxidation. Linking site-specific data with existing globally-validated USDA models for annual climate and soil microclimate (Global TempSim; Global RainSim; Solarcalc; STM2), this model relies on 1-D diffusion as the major driver for emissions. Importantly, unlike current inventory methods based on modeled generation, the driving force for emissions (e.g., the CH4 concentration gradient) can be directly compared to field data. Methane oxidation is scaled to maximum rates over the full range of moisture and temperature conditions based on extensive supporting laboratory studies using California landfill cover soils. Field validation included meteorological data, soil moisture/temperature measurements, and seasonal (wet/dry) CH4 emissions & oxidation measurements for daily, intermediate, and final cover soils over two annual cycles at a northern (Monterey County) and southern California (Los Angeles County) landfill. The model accurately predicted soil temperature and moisture trends for individual cover materials with acceptable order-of-magnitude predictability for field emissions within the context of published literature spanning 7 orders of magnitude. In addition to regional defaults for inventory purposes, CALMIM permits user-selectable parameters and boundary conditions for more rigorous site-specific applications where detailed CH4 emissions, meteorological, and soil microclimate data exist.

  9. Organization of retrospective monitoring of the soil cover in Azov district of Rostov oblast

    NASA Astrophysics Data System (ADS)

    Bryzzhev, A. V.; Rukhovich, D. I.; Koroleva, P. V.; Kalinina, N. V.; Vil'chevskaya, E. V.; Dolinina, E. A.; Rukhovich, S. V.

    2015-10-01

    Retrospective monitoring of the state of soils and lands is based on the principles of actualization of their identification features based on the available materials of remote sensing (RS). The characteristics of RS materials and topographic maps applied for this purpose are discussed. It is argued that temporal changes in the state of soils and lands can be inferred from three types of RS materials covering the entire agricultural territory of Russia. Information about the availability of these materials is given. The methodology of retrospective monitoring of the state of soils and lands is realized with the use of GIS technologies. Classification schemes of the types of land use and their dynamics for the considered region are suggested.

  10. Emissions of air-borne mercury from five municipal solid waste landfills in Guiyang and Wuhan, China

    NASA Astrophysics Data System (ADS)

    Li, Z.-G.; Feng, X.; Li, P.; Liang, L.; Tang, S.-L.; Wang, S.-F.; Fu, X.-W.; Qiu, G.-L.; Shang, L.-H.

    2010-04-01

    China disposes of bulk Municipal Solid Waste (MSW) by landfilling, resulting in a large quantity of mercury that enters landfills through waste. A detailed study on atmospheric mercury emissions from MSW landfills in China is necessary to understand mercury behavior from this source. Between 2003 and 2006, mercury airborne emissions through different pathways, as well as mercury speciation in Landfill Gas (LFG) were measured at 5 MSW landfills in Guiyang and Wuhan, China. The results showed that mercury content in the substrate increased the magnitude of mercury emissions, with the highest emission rate measured at the working face and in uncovered waste areas, and the lowest measured near soil covers and vegetated areas. Meteorological parameters, especially solar radiation, influenced the diurnal pattern of mercury surface-air emissions. Total Gaseous Mercury (TGM) in LFG varied from 2.0 to 1406.0 ng m-3, Monomethyl Mercury (MMHg) and Dimethyl Mercury (DMHg) in LFG averaged at 1.93 and 9.21 ng m-3, and accounted for 0.51% and 1.79% of the TGM in the LFG, respectively. Total mercury emitted from the five landfills ranged from 17 to 3300 g yr-1, with the highest from the working face, then soil covering, and finally the vent pipes.

  11. [Radioecological investigation of the soil cover of eastern Urals State radioactive reserve and neighboring areas].

    PubMed

    Mikhaĭlovskaia, L N; Molchanova, I V; Karavaeva, E N; Pozolotina, V N; Tarasov, O V

    2011-01-01

    The contamination levels and spatial distribution of 90Sr and 137Cs in the soil cover of the Eastern Ural State Radioactive Reserve and neighboring areas have been studied. Situated in the Chelyabinsk region, the Reserve embraces the frontal part of the Eastern Urals Radioactive Trace. This Trace emerged in 1957 as a result of the nuclear accident at the Production Association "Mayak". In the studied areas, the content of radionuclides in soils decreases exponentially as the distance from the source of contamination increases. 90Sr received by the soil cover as a result of the accident in 1957 has remained the main contaminant of the Reserve central part (97% of the total contamination). Its contribution throughout western neighboring areas reduces up to 67%, which decreases the effect of 90Sr on the environment. Within eastern neighboring areas, soil is mainly contaminated by 137Cs received as a result of the wind disseminated dried sediments from the shores of Lake Karachay (1967) that was used for dumping high-level radioactive waste. Also observed was enrichment of forest litters with this radionuclide due to current atmospheric fallout. PMID:21950106

  12. Rye cover crop effects on soil quality in no-till corn silage-soybean cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Corn and soybean farmers in the upper Midwest are showing increasing interest in winter cover crops. Known benefits of winter cover crops include reductions in nutrient leaching, erosion prevention, and weed suppression; however, the effects of winter cover crops on soil quality in this region have ...

  13. Parameterization of Organic-covered Permafrost Soils in Land Surface and Hydrological Models

    NASA Astrophysics Data System (ADS)

    Zhang, Y.; Carey, S. K.; Quinton, W. L.; Janowicz, R.

    2009-05-01

    Close to one-third of the earth's surface is underlain with permafrost and much of the permafrost terrain is covered with a surface organic layer of various depths. The need to improve mathematical representation and parameterization of cold region processes in land surface and hydrological models have been well recognized in recent decades. However, progress has been hindered by (a) the complexity and variability of the soil system associated with thawing/freezing processes and organic cover and (b) the shortage of high quality field data due to the technical and logistic difficulties imposed by the harsh environments. Large variations exist in the parameterizations of thermal and hydrological processes in current land surface and hydrological models. Many of them were developed and validated in soil and climate conditions different from those in permafrost regions. In this study, efforts have been made to examine the most important thermal and hydraulic parameterizations and their effects on the simulations of ground thawing/freezing and infiltration/runoff processes against detailed measurements obtained at six field sites in Canada's discontinuous permafrost region. The tested parameterizations include (a) three methods for thermal conductivity, (b) three methods for hydraulic conductivity and soil water retention, (c) three methods for unfrozen water content, (d) six algorithms for thawing/freezing simulation and (e) five algorithms for infiltration simulation. The field sites cover various vegetation types including boreal forest, alpine tundra and wetland peat plateau. The soil organic depth ranges from 0.0 to 3 m. Field data used include daily meteorological variables (solar radiation, air temperature, relative humidity, precipitation and wind speed), daily liquid soil water content and soil temperature at various depths, and daily snow depth. Total soil water content (frozen and liquid) was monitored using twin probe gamma attenuation at three sites. Ground thawing and freezing depths, snow melt, infiltration and runoff were estimated from the above measurements. Methods of different parameterization were compared using identical inputs and evaluated against the same set of observed outputs. The main conclusions of this study include: (a) de Vries' method is recommended to parameterize the thermal conductivity in permafrost soils; (b) the van Genuchten method provides the best fit to the observed soil hydraulic curves, but has the most parameters. while the Brooks and Corey method and Clapp and Hornberger method achieve similar results for most soil moisture conditions as long as appropriate parameters were chosen; (c) the segmented linear function is the simplest to be parameterized with limited available data, while the water potential-freezing point depression equation is recommend for coupled thermal and moisture simulations; (d) a numerical model with an apparent heat capacity treatment gives the most accurate simulation of ground thawing/freezing depths in all the tested sites; and (e) no current infiltration scheme is valid for all the infiltration situations in organic-covered permafrost soils as different methods must be employed in different infiltration stages.

  14. Phytoremediation of landfill leachate

    SciTech Connect

    Jones, D.L. . E-mail: d.jones@bangor.ac.uk; Williamson, K.L.; Owen, A.G.

    2006-07-01

    Leachate emissions from landfill sites are of concern, primarily due to their toxic impact when released unchecked into the environment, and the potential for landfill sites to generate leachate for many hundreds of years following closure. Consequently, economically and environmentally sustainable disposal options are a priority in waste management. One potential option is the use of soil-plant based remediation schemes. In many cases, using either trees (including short rotation coppice) or grassland, phytoremediation of leachate has been successful. However, there are a significant number of examples where phytoremediation has failed. Typically, this failure can be ascribed to excessive leachate application and poor management due to a fundamental lack of understanding of the plant-soil system. On balance, with careful management, phytoremediation can be viewed as a sustainable, cost effective and environmentally sound option which is capable of treating 250 m{sup 3} ha{sup -1} yr{sup -1}. However, these schemes have a requirement for large land areas and must be capable of responding to changes in leachate quality and quantity, problems of scheme establishment and maintenance, continual environmental monitoring and seasonal patterns of plant growth. Although the fundamental underpinning science is well understood, further work is required to create long-term predictive remediation models, full environmental impact assessments, a complete life-cycle analysis and economic analyses for a wide range of landfill scenarios.

  15. Phytoremediation of landfill leachate.

    PubMed

    Jones, D L; Williamson, K L; Owen, A G

    2006-01-01

    Leachate emissions from landfill sites are of concern, primarily due to their toxic impact when released unchecked into the environment, and the potential for landfill sites to generate leachate for many hundreds of years following closure. Consequently, economically and environmentally sustainable disposal options are a priority in waste management. One potential option is the use of soil-plant based remediation schemes. In many cases, using either trees (including short rotation coppice) or grassland, phytoremediation of leachate has been successful. However, there are a significant number of examples where phytoremediation has failed. Typically, this failure can be ascribed to excessive leachate application and poor management due to a fundamental lack of understanding of the plant-soil system. On balance, with careful management, phytoremediation can be viewed as a sustainable, cost effective and environmentally sound option which is capable of treating 250m(3)ha(-1)yr(-1). However, these schemes have a requirement for large land areas and must be capable of responding to changes in leachate quality and quantity, problems of scheme establishment and maintenance, continual environmental monitoring and seasonal patterns of plant growth. Although the fundamental underpinning science is well understood, further work is required to create long-term predictive remediation models, full environmental impact assessments, a complete life-cycle analysis and economic analyses for a wide range of landfill scenarios. PMID:16168631

  16. Effects of compaction and wetting of laterite cover soil on development and survival of Musca domestica (Diptera: Muscidae) immatures.

    PubMed

    Abu Tahir, Nurita; Ahmad, Abu Hassan

    2013-09-01

    Effects of laterite cover soil with different characteristics on survival of buried eggs, third instar larvae, and pupae of Musca domestica (L.) were studied experimentally. Soil treatments were loose dry soil, loose wet soil, compacted dry soil, and compacted wet soil (CWS). Eggs, third instar larvae, and pupae were buried under 30 cm of the different soil treatments and placed under field conditions until adults emerged. Rearing medium was provided for eggs and larvae, and control treatments of all stages were unburied immatures placed on soil surface. Egg and pupal survival to adult were significantly affected by the cover soil treatments, but third instars were more resilient. Wet soil treatments (loose wet soil and CWS) resulted in significantly reduced pupal survival, but increased survival of eggs. However, CWS significantly reduced adult emergence from buried eggs. Though emergence of house flies buried as eggs was significantly reduced, some were able to hatch and emerging first instar larvae developed to pupation. Although cover soil does not completely prevent fly emergence, it did limit development and emergence of buried house flies. PMID:24180104

  17. Cover crops impact on excess rainfall and soil erosion rates in orchards and potato fields, Israel

    NASA Astrophysics Data System (ADS)

    Egozi, Roey; Gil, Eshel

    2015-04-01

    Bare soil and high drainage densities are common characteristics of intensive agriculture land. The couplings of these characteristics lead to high runoff and eroded soil volumes leaving the field or the orchard via the local drainage system into the fluvial system. This process increase flood risk due to massive deposition of the coarse fraction of the eroded soil and therefore reduces channel capacity to discharge the increase volumes of concentrated runoff. As a result drainage basin authorities are forced to invest large amount of money in maintaining and enlarging the drainage network. However this approach is un-sustainable. On the other hand, implementing cover crops (CC) and modification to current agricultural practices over the contributing area of the watershed seems to have more benefits and provide sustainable solution. A multi-disciplinary approach applied in commercial potatoes fields and orchards that utilize the benefit of CC shows great success as means of soil and water conservation and weed disinfestation without reduction in the yield, its quality or its profitability. The results indicate that it is possible to grow potatoes and citrus trees under CC with no reduction in yield or nutrient uptake, with more than 95% reduction in soil loss and more than 60% in runoff volumes and peak discharges.

  18. Use of LANDSAT images of vegetation cover to estimate effective hydraulic properties of soils

    NASA Technical Reports Server (NTRS)

    Eagleson, Peter S.; Jasinski, Michael F.

    1988-01-01

    The estimation of the spatially variable surface moisture and heat fluxes of natural, semivegetated landscapes is difficult due to the highly random nature of the vegetation (e.g., plant species, density, and stress) and the soil (e.g., moisture content, and soil hydraulic conductivity). The solution to that problem lies, in part, in the use of satellite remotely sensed data, and in the preparation of those data in terms of the physical properties of the plant and soil. The work was focused on the development and testing of a stochastic geometric canopy-soil reflectance model, which can be applied to the physically-based interpretation of LANDSAT images. The model conceptualizes the landscape as a stochastic surface with bulk plant and soil reflective properties. The model is particularly suited for regional scale investigations where the quantification of the bulk landscape properties, such as fractional vegetation cover, is important on a pixel by pixel basis. A summary of the theoretical analysis and the preliminary testing of the model with actual aerial radiometric data is provided.

  19. The Application Of Biofilter System For Reduction Of Methane Emissions From Modern Sanitary Landfills

    NASA Astrophysics Data System (ADS)

    Sung, K.; Park, S.

    2007-12-01

    Increased atmospheric concentrations of greenhouse gases (GHG) caused by anthropogenic activities has been related to global climate change. Methane, the second most important GHG after CO2, is 21 times more effective at trapping heat than CO2. Therefore, methane emission control is of utmost importance for global warming reduction. To minimize leachate production and protect groundwater resources, modern sanitary landfills are equipped with composite covers and gas collection systems. Methane from modern sanitary landfills is vented directly to the atmosphere, except for some of the largest landfills where it is recovered as energy and burned at the site. However, the efficiency of energy recovery systems in larger landfills is reduced as the amount of CH4 generated from landfill begins to decrease. In this study, the performance of a lab-scale model biofilter system was investigated to treat CH4 gas emitted from modern sanitary landfills by conducting batch and column experiments using landfill cover soil amended with earthworm cast as the filter bed medium. From the batch experiments to measure the influence of moisture content and temperature of the filter medium on CH4 removal capacity of a biofilter system, the optimum moisture content and temperature were found to be 10-15% by weight and 25-35°C, respectively. The column experiment was conducted to measure the influence of inlet CH4 concentration and CH4 loading rate on CH4 removal capacity of a biofilter system. As the inlet CH4 concentration decreased, the percentage of CH4 oxidized increased. Up to a CH4 loading rate of 2785 g CH4 m3 h- 1 (EBRT = 7.7 min), the CH4 removal efficiency of the biofilter was able to reach 100%. Based on the results of the study, the installation of a properly managed biofilter system should be capable of achieving a reduction in atmospheric CH4 emissions from modern sanitary landfills at low CH4 generation stage.

  20. Cover Crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cover crops are a beneficial tool for use in conservation tillage systems. Cover crop residues reduce soil erosion from water and wind, increase soil water availability for subsequent crops, enhance soil organic matter and biological activity, and can decrease labor and energy inputs. Cover crop...

  1. Permafrost Thermal Properties and Thaw and its Relationship to Soil and Plant Cover, Lake Hovsgol, Mongolia

    NASA Astrophysics Data System (ADS)

    Goulden, C. E.; Etzelmuller, B.; Ariuntsetseg, L.; Nandintsetseg, B.; Avirmed, O.; Batkhishig, O.; Sharkhuu, A.; Sharkhuu, N.

    2005-12-01

    Northern Mongolia represents the southern-most extension of continuous permafrost and the border of the Siberian taiga forest in Asia. The mountainous watershed valleys of Lake Hvsgl are in a forest/steppe transition zone characterized by continuous permafrost in the upper valleys and ridge tops and discontinuous permafrost in lower valley areas. Valley bottoms and south-facing slopes have steppe vegetation dominated by grasses and sedges with increasing amounts of forbs in heavily grazed areas. North-facing slopes and ridges are covered by taiga forest, dominated by larch. The mean annual air temperature in the region is 4.5C. Total annual precipitation averages about 300 mm with most falling in mid summer. The objectives of this research include the identification of the spatial distribution of permafrost and possible permafrost thaw associated with modifications in the watersheds due to nomadic pastoralism and to climate change. Permafrost thaw has been documented elsewhere at the Lake and there are indications that a severe thaw has occurred in the study area as a result of heavy pastoralism. We are monitoring changes and experimentally testing factors that maintain low soil temperatures and high soil moisture in six valleys that have similar meteorological conditions but affected by pastoralism ranging from heavy grazing in two northern valleys, to light or no grazing in two southern valleys, and moderate grazing in the middle two valleys. Soil temperature and soil moisture are measured in plots in each valley, composing a range of soil and plant densities and texture, largely dependent upon livestock grazing levels. Experiments are measuring decomposition rates for different plant taxa, and effect of different amounts of necromass cover on soil temperature and soil moisture. In this paper we contrast conditions in the six valleys. The area has warmed by 1.6C between 1963 and 2004 (P <0.0001) but there has been no corresponding significant change in annual precipitation. There also has been a shift towards a longer growing season as a result of the warming trend. The objective of this presentation is to assess the highly complex relationships between climate warming, grazing, vegetation cover and the thermal state of permafrost. Permafrost and the active layer thickness is a governing factor for available soil moisture for plant growth, and thus affects the soil water balance. The increase of the active layer thickness rapidly leads to drying out the soils resulting in a change of soil thermal regime and vegetation composition. First model estimations show an increased evapotranspiration in the last 10 years. Ground temperatures are monitored in 16 boreholes in the region since 2002, and during this period some differences are evident, e.g., active layer thicknesses in morphometrically similar topographic positions are higher in grassed than in un-grassed settings. Comparable results of vegetation-permafrost interactions are revealed by an intensive measurement campaign of DC resistivity tomography.

  2. Infiltration through layered-soil trench covers: Response to an extended period of rainfall

    USGS Publications Warehouse

    Larson, T.H.; Keefer, D.A.; Albrecht, K.A.; Cartwright, K.

    1988-01-01

    Four experimental waste disposal trench covers were constructed to test the effectiveness of layered-soil cover designs in reducing infiltration. Three covers each consisted of a layer of gravel between an overlying wick layer of compacted fine-grained material (either silt or loam) and a compacted loam base; the fourth consisted of compactd silt over a loam base. Capillary pressures were monitored at various depths within each cover during October through December, 1985, a period of high rainfall following a dry summer. Moisture movement in response to the rainfall was rapid within the upper layers of all four test covers, but was retained within the upper layers of the three wick-system trenches, despite variations in the design thickness and composition of the wick layers. In the wick systems, moisture did not enter the gravel until a threshold level of pressure approaching saturation was established in the wick layer. Once this level was reached, moisture moved into and through the gravel. This experiment demonstrates the functionality of field-scale wick systems. ?? 1988.

  3. A map of the soil cover patterns in the western part of the Transbaikal region (1: 500000 scale)

    NASA Astrophysics Data System (ADS)

    Gonchikov, B.-M. N.; Tsybzhitov, Ts. Kh.; Tsybikdorzhiev, Ts. Ts.; Davydova, T. V.

    2009-07-01

    The results of soil surveys in the Khorinsk district of the Buryat Republic have been generalized on a map of the soil cover patterns on a scale of 1: 500000. The map reflects the soil cover patterns in the zones of mountainous tundra and taiga, mountainous forest-steppes, sand massifs on piedmonts, and plain steppes and dry steppes. The areas of each component of the soil combinations shown on the map have been calculated. In the course of the generalization of large-scale soil maps, information on the genetic types and subtypes of soils has been preserved. The new map adequately displays the real pattern of the soil distribution in the studied area.

  4. Comparison of deep percolation rates below contrasting land covers with a joint canopy and soil model

    NASA Astrophysics Data System (ADS)

    Domínguez, C. G.; Pryet, A.; García Vera, M.; Gonzalez, A.; Chaumont, C.; Tournebize, J.; Villacis, M.; d'Ozouville, N.; Violette, S.

    2016-01-01

    A Rutter-type canopy interception model is combined with a 1-D physically-based soil water flow model to compare deep percolation rates below distinct land covers. The joint model allows the quantification of both evaporation and transpiration rates as well as deep percolation from vegetation and soil characteristics. Experimental observations are required to constitute the input and calibration datasets. An appropriate monitoring design is described which consists in meteorological monitoring together with throughfall and soil water tension measurements. The methodology is illustrated in Santa Cruz Island in the Galapagos Archipelago, which has been affected by significant land use changes. Two adjacent study plots are investigated: a secondary forest and a pasture. The results of the model reveal that evaporation of canopy interception is higher in the pasture due to the bigger canopy storage capacity, which promotes evaporation against canopy drainage. This is however compensated by higher transpiration in the secondary forest, due to the smaller surface resistance. As a consequence, total evapotranspiration is similar for the two plots and no marked difference in deep percolation can be observed. In both cases, deep percolation reaches ca. 2 m/year which corresponds to 80% of the incoming rainfall. This methodology not only allows the quantification of deep percolation, but can also be used to identify the controlling factors of deep percolation under contrasting land covers.

  5. Soil formation and mass fluxes in cover beds of the Kowarski Grzbiet (eastern Karkonosze Mountains)

    NASA Astrophysics Data System (ADS)

    Waroszewski, Jaroslaw; Egli, Markus; Brandov, Dagmar; Pltze, Michael; Kabala, Cezary; Kierczak, Jakub

    2014-05-01

    The Karkonosze Mountains are a Hercynian mid-mountain range located in the Central Europe, at the border of Poland and the Czech Republic. Although granite is the dominant geology in the western and middle part of the mountain belt, the eastern part consists mainly of different types of the schists and gneiss. Small mountain glaciers that developed during the late Weichselian, periglacial conditions as well as an intense activity of slope processes during the Atlantic and at the Atlantic/Sub-Boreal transition have shaped the landscape during the Quaternary and formed sequences of cover beds which became the main parent material of soils. In our study we focused on the eastern, metamorphic part that is characterised by mica schist, amphibole schist and gneiss. A transect was studied along the slope of Skalny Stol (1281 m as.l) of the Kowarski Grzbiet having NW exposition. This transect included 5 profiles along a slope section from 1269 m asl to 1142 m asl. In all profiles, at least three layers could be distinguished: (a) a basal layer formed probably in the Younger Dryas with features of solifluction - found in almost every relief position (b) a transition periglacial zone, interpreted as a result of cryoturbation, and (c) a top cover having almost no rock fragments and most likely relatively young (Holocene) appeared in all profiles. However, in some soils, colluvial material was found in the topsoil. Within the stony cover bed, at the flat plateaus and in the upper section of slope Hyperskeletic and Skeletic Podzols have developed (the basal and transition layer contained amphibole schist and the top layer only mica schist). In the middle and lower slope position where gelisolifluction layers were detected, colluvial material was superimposed and as a consequence Cambisols and Stagnosols have developed. Consequently, the soil distribution pattern in this landscape is strongly affected by the arrangement of the slope deposits. Sediments having a different age and origin should reflect different weathering mechanisms and clay minerals formation and transformation processes. To check this hypothesis we: (i) identified clay minerals using qualitative and semi-quantitative methods, (ii) measured total element content in fine earth using X-ray fluorescence, (iii) calculated weathering indexes such as the (K+Ca)/Ti ratio, indexes A and B and (iv) measured erosion rates using 10Be in soils. These measurements confirmed the complex soil formation characteristics of the soils and demonstrated the highly dynamic system of slope deposits (in terms of matter fluxes).

  6. Movement of unlined landfill under preloading surcharge.

    PubMed

    Al-Yaqout, Anwar F; Hamoda, Mohamed F

    2007-01-01

    As organic solid waste is decomposed in a landfill and mass is lost due to gas and leachate formation, the landfill settles. Settlement of a landfill interferes with the rehabilitation and subsequent use of the landfill site after closure. This study examined the soil/solid waste movement at the Al-Qurain landfill in Kuwait after 15 years of closure as plans are underway for redevelopment of the landfill site that occupies about a km(2) with an average depth of 8-15m. Field experiments were conducted for 6 mo to measure soil/solid waste movement and water behavior within the landfill using two settlement plates with a level survey access, Casagrande-type piezometers, pneumatic piezometers, and magnetic probe extensometers. Previous results obtained indicated that biological decomposition of refuse continued after closure of the landfill site. The subsurface water rise enhanced the biological activities, which resulted in the production of increasing quantities of landfill gas. The refuse fill materials recorded a high movement rate under the imposed preloading as a result of an increase in the stress state. Up to 55% of the total movement was observed during the first 2 weeks of fill placement and increased to 80% within the first month of the 6-mo preloading test. Pneumatic piezometers showed an increase in water head, which is attributed to the developed pressure of gases escaping during the preloading period. PMID:16574394

  7. Land-cover effects on soil organic carbon stocks in a European city.

    PubMed

    Edmondson, Jill L; Davies, Zoe G; McCormack, Sarah A; Gaston, Kevin J; Leake, Jonathan R

    2014-02-15

    Soil is the vital foundation of terrestrial ecosystems storing water, nutrients, and almost three-quarters of the organic carbon stocks of the Earth's biomes. Soil organic carbon (SOC) stocks vary with land-cover and land-use change, with significant losses occurring through disturbance and cultivation. Although urbanisation is a growing contributor to land-use change globally, the effects of urban land-cover types on SOC stocks have not been studied for densely built cities. Additionally, there is a need to resolve the direction and extent to which greenspace management such as tree planting impacts on SOC concentrations. Here, we analyse the effect of land-cover (herbaceous, shrub or tree cover), on SOC stocks in domestic gardens and non-domestic greenspaces across a typical mid-sized U.K. city (Leicester, 73 km(2), 56% greenspace), and map citywide distribution of this ecosystem service. SOC was measured in topsoil and compared to surrounding extra-urban agricultural land. Average SOC storage in the city's greenspace was 9.9 kg m(-2), to 21 cm depth. SOC concentrations under trees and shrubs in domestic gardens were greater than all other land-covers, with total median storage of 13.5 kg m(-2) to 21 cm depth, more than 3 kg m(-2) greater than any other land-cover class in domestic and non-domestic greenspace and 5 kg m(-2) greater than in arable land. Land-cover did not significantly affect SOC concentrations in non-domestic greenspace, but values beneath trees were higher than under both pasture and arable land, whereas concentrations under shrub and herbaceous land-covers were only higher than arable fields. We conclude that although differences in greenspace management affect SOC stocks, trees only marginally increase these stocks in non-domestic greenspaces, but may enhance them in domestic gardens, and greenspace topsoils hold substantial SOC stores that require protection from further expansion of artificial surfaces e.g. patios and driveways. PMID:24309424

  8. Impact of urban cover fraction on SMOS and SMAP surface soil moisture retrieval

    NASA Astrophysics Data System (ADS)

    Ye, N.; Walker, J. P.; Rudiger, C.; Ryu, D.; Gurney, R.

    2011-12-01

    L-band (~1.4 GHz) microwave radiometry has been widely acknowledged as the most promising technique for surface (top ~5cm) soil moisture observation at regional and global scales, due to its all weather capability, direct relationship to soil moisture, and reduced sensitivity to surface roughness and vegetation. Radiometer observations of microwave emission from the soil surface are used to estimate soil moisture through a radiative transfer model using ancillary information including land cover and soil properties etc. This technique has been applied to the ESA's (European Space Agency) Soil Moisture and Ocean Salinity (SMOS) satellite, the first soil moisture dedicated space mission, launched on 2nd Nov. 2009. Similarly, radiometer techniques will be employed by NASA's (National Aeronautics and Space Administration) Soil Moisture Active and Passive (SMAP) mission, in both the passive and active-passive products. However, passive microwave soil moisture retrieval suffers from land surface heterogeneity at coarse scales; with the radiometer footprints of both missions being ~40 km, which is the best spatial resolution currently achievable using current satellite antenna technology. In order to achieve the ~0.04 m3/m3 target volumetric soil moisture accuracies at such scales, microwave contributions of non-soil targets (such as urban areas) within the sensors' field-of-view needs to be considered in the retrieval algorithm error budget and implementation, since the impact could potentially be significant if ignored. Currently there is a lack of knowledge on the microwave behaviour of non-soil targets, with little assessment of their microwave emissions and impact on satellite scale footprints. Therefore, the objectives of this study are to 1) investigate the relationship between urban induced brightness temperature uncertainties and urban fraction, 2) extract urban fraction thresholds for negligible brightness temperature impact by urban areas based on the SMOS and SMAP error budgets, and 3) use these thresholds to identify SMOS and SMAP pixels with likely non-negligible urban impacts world-wide. In this work, airborne datasets from three field campaigns in the Murrumbidgee catchment, in southeast of Australia, were used: i) the NAFE'06 (National Airborne Field Experiment in 2006), ii) the AACES-1 (Australian Airborne Cal/val Experiment for SMOS), and iii) the AACES-2. During these campaigns, brightness temperature observations were made at 1-km resolution across 20 independent SMOS/SMAP sized footprints of which a number contain urban areas of different size. The NSW (New South Wales, Australia) Land use map with 50 m resolution was used to distinguish brightness temperature observations of the urban area and surrounding natural land surface, from which urban fraction thresholds for SMOS and SMAP were derived. These thresholds were then applied globally based on an urban fraction map calculated using the MODIS Urban Land Cover 500-m product.

  9. Geologic and hydrologic data for the municipal solid waste landfill facility, U.S. Army Air Defense Artillery Center and Fort Bliss, El Paso County, Texas

    USGS Publications Warehouse

    Abeyta, Cynthia G.; Frenzel, P.F.

    1999-01-01

    Geologic and hydrologic data for the Municipal Solid Waste Landfill Facility on the U.S. Army Air Defense Artillery Center and Fort Bliss in El Paso County, Texas, were collected by the U.S. Geological Survey in cooperation with the U.S. Department of the Army. The 106.03-acre landfill has been in operation since January 1974. The landfill contains household refuse, Post solid wastes, bulky items, grass and tree trimmings from family housing, refuse from litter cans, construction debris, classified waste (dry), dead animals, asbestos, and empty oil cans. The depth of the filled areas is about 30 feet and the cover, consisting of locally derived material, is 2 to 3 feet thick. Geologic and hydrologic data were collected at or adjacent to the landfill during (1) drilling of 10 30- to 31-foot boreholes that were completed with gas-monitoring probes, (2) drilling of a 59-foot borehole, (3) drilling of a 355-foot borehole that was completed as a ground-water monitoring well, and (4) in situ measurements made on the landfill cover. After completion, the gas- monitoring probes were monitored on a quarterly basis (1 year total) for gases generated by the landfill. Water samples were collected from the ground-water monitoring well for chemical analysis. Data collection is divided into two elements: geologic data and hydrologic data. Geologic data include lithologic descriptions of cores and cuttings, geophysical logs, soil- gas and ambient-air analyses, and chemical analyses of soil. Hydrologic data include physical properties, total organic carbon, and pH of soil and sediment samples; soil-water chloride and soil-moisture analyses; physical properties of the landfill cover; measurements of depth to ground water; and ground-water chemical analyses. Interpretation of data is not included in this report.

  10. Cover crops influence soil microorganisms and phytoextraction of copper from a moderately contaminated vineyard.

    PubMed

    Mackie, K A; Schmidt, H P; Müller, T; Kandeler, E

    2014-12-01

    We investigated the ability of summer (Avena sativa [oat], Trifolium incarnatum [crimson clover], Chenopodium [goosefoot]) and winter (Vicia villosa [hairy vetch], Secale Cereale L. [Rye], Brassica napus L. partim [rape]) cover crops, including a mixed species treatment, to extract copper from an organic vineyard soil in situ and the microbial communities that may support it. Clover had the highest copper content (14.3mgCukg(-1) DM). However, it was the amount of total biomass production that determined which species was most effective at overall copper removal per hectare. The winter crop rye produced significantly higher amounts of biomass (3532kgDMha(-1)) and, therefore, removed significantly higher amounts of copper (14,920mgCuha(-1)), despite less accumulation of copper in plant shoots. The maximum annual removal rate, a summation of best performing summer and winter crops, would be 0.033kgCuha(-1)y(-1). Due to this low annual extraction efficiency, which is less than the 6kgCuha(-1)y(-1) permitted for application, phytoextraction cannot be recommended as a general method of copper extraction from vineyards. Copper concentration did not influence aboveground or belowground properties, as indicated by sampling at two distances from the grapevine row with different soil copper concentrations. Soil microorganisms may have become tolerant to the copper levels at this site. Microbial biomass and soil enzyme activities (arylsulfatase and phosphatase) were instead driven by seasonal fluxes of resource pools. Gram+ bacteria were associated with high soil moisture, while fungi seemed to be driven by extractable carbon, which was linked to high plant biomass. There was no microbial group associated with the increased phytoextraction of copper. Moreover, treatment did not influence the abundance, activity or community structure of soil microorganisms. PMID:25217742

  11. Effects of Tillage, Rotation and Cover Crop on the Physical Properties of a Silt-Loam Soil

    NASA Astrophysics Data System (ADS)

    Haruna, Samuel Idoko; Nkongolo, Nsalambi Vakanda

    2015-04-01

    Soil and crop management practices can affect the physical properties and have a direct impact on soil sustainability and crop performance. The objective of this study was to investigate how soil physical properties were affected by three years of tillage, cover crop and crop rotation treatments in a corn and soybean field. The study was conducted on a Waldron siltyloam soil at Lincoln University of Missouri. Soil physical properties studied were soil bulk density, volumetric and gravimetric water contents, volumetric air content, total pore space, air-filled and water-filled pore space, gas diffusion coefficient and pore tortuosity factor. Results showed significant interactions (p<0.05) between cover crop and crop rotation for bulk density, gravimetric and total pore space in 2013. In addition, cover crop also significantly interacted (p<0.05) with tillage for bulk density and total pore space. All soil physical properties studied were significantly affected by the depth of sampling (p<0.0001), except for bulk density, the pore tortuosity factor and total pore space in 2012, and gravimetric and volumetric in 2013. Overall, soil physical properties were significantly affected by the treatments, with the effects changing from one year to another. Addition of a cover crop improved soil physical properties better in rotation than in monoculture.

  12. The applicability of ERTS-1 data covering the major landforms of Kenya. [landforms, vegetation, soils, forests

    NASA Technical Reports Server (NTRS)

    Omino, J. H. O. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Five investigators report on the applicability of ERTS-1 data covering the major landforms of Kenya. Deficiencies due to lack of equipment, repetitive coverage and interpretation know-how are also reported on. Revision of lake shorelines is an immediate benefit. Basement system metasediments are rapidly differentiated, but dune areas are not readily distinguishable from sandy soils. Forest, moorland, high altitude grass, tea, and conifer plantations are readily distinguished, with podocarpus forest especially distinguishable from podocarpus/juniperus forest. In the arid areas physiographic features, indicating the major soil types, are readily identified and mapped. Preliminary vegetation type analysis in the Mara Game Reserve indicates that in a typical savannah area about 36% of the vegetation types are distinguishable at a scale of 1:1 million as well as drainage patterns and terrain features.

  13. Biogenic NO emission from a spruce forest soil in the Fichtelgebirge (Germany) under the influence of different understorey vegetation cover

    NASA Astrophysics Data System (ADS)

    Bargsten, A.; Andreae, M. O.; Meixner, F. X.

    2009-04-01

    Within the framework of the EGER project (ExchanGE processes in mountainous Regions) soil samples have been taken from the spruce forest site "Weidenbrunnen" (Fichtelgebirge, Germany) in September 2008 to determine the NO exchange in the laboratory and for a series of soil analyses. The soil was sampled below different understorey vegetation covers: young Norway spruce, moss/litter, blueberries and grass. We investigated the net NO release rate from corresponding organic layers as well as from the A horizon of respective soils. Additionally we measured pH, C/N ratio, contents of ammonium, nitrate, and organic C, bulk density, the thickness of the organic layer and the quality of the organic matter. Net NO release rates (as well as the NO production and NO consumption rates) from the soil samples were determined by a fully automated laboratory incubation & fumigation system. Purified dry air passed five dynamic incubation chambers, four containing water saturated soil samples and one reference chamber. By this procedure, the soil samples dried out slowly (within 2-6 days), covering the full range of soil moisture (0-300% gravimetric soil moisture). To quantify NO production and NO consumption rates separately, soil samples were fumigated with zero-air (approx. 0 ppb NO) and air of 133 ppb NO. The chambers were placed in a thermostatted cabinet for incubation at 10 an 20˚ C. NO and H2O concentrations at the outlet of the five dynamic chambers were measured sequentially by chemiluminescence and IR-absorption based analyzers, switching corresponding valves every two minutes. Net NO release rates were determined from the NO concentration difference between soil containing and reference chambers. Corresponding measurements of H2O mixing ratio yielded the evaporation loss of the soil samples, which (referenced to the gravimetric soil water content before and after the incubation experiment) provided the individual soil moisture contents of each soil samples during the incubation experiment. Our contribution focus net NO release rates, NO production and NO consumption rates of spruce forest soils sampled under different understorey vegetation covers. Generally, organic layers show significant higher NO production and NO consumption rates than the soils from the corresponding A horizons. Soils under the understorey vegetation cover "moos/litter" revealed the lowest NO production and NO consumption rates. Net NO release rates, NO production and NO consumption rates of soil samples obtained below the four different under- storey vegetation covers will be discussed in terms of pH, C/N ratio, contents of ammonium, nitrate, and organic C, bulk density, thickness of organic layer, as well as quality of the organic matter.

  14. Technogenic contaminations of the soil-plant cover in the Primorsky Krai, Russia

    NASA Astrophysics Data System (ADS)

    Molchanova, Inna; Pozolotina, Vera; Mikhailovskaya, Ludmila; Antonova, Elena; Zhuravlev, Yury; Timofeeva, Yana; Burdukovsky, Maxim

    2013-04-01

    All economical development of the countries carries out monitoring as with the aim to estimate impact of the industrial enterprises and nuclear-energetic complexes as consequences of the nuclear accidents. The investigation the region of the Far East due to proximity to epicentre of accident on Fukushima-1 NPP is of a great interest. The aim of this work are radioecological investigations and estimate technogenic load on the ecosystems of tightly populated plots of the shore zone of the Vladivostok region. Eight plots were located on the investigated territory. The tree fall, forest litters and soils were sampling from the profile cuts of layer by layer, up to 20 cm. The artificial radionuclides (Sr-90 and Cs-134,137), as heavy metals and microelements (Co, Cu, Zn, Pb and Mn) content in the prepared samples was determined. The stock of Sr-90 fluctuates from 0.3 to 1.3 kBq/m2 and Cs-137 was from 0.4 to 3.0 kBq/m2 in the examined soils. On the whole, the level of the radionuclides content in the soil cover is within the limits of the background that was formed in the belt between 50 and 60 of northern latitude. The presence in investigated samples of Cs-134 indicates to contribution of accidental fallout of Fukushima-1 into contamination of the components of the natural ecosystems. In a year's time after the accident the stock of this isotope in the soils was 0.01-0.20 kBq/m^2. It is by factor of 10-100 lower than the stock of Cs-137. Taking into account that the ratio Cs-134/Cs-137 on the moment of accident was equal to unity (1:1). It can be estimated the quantity of Cs-137 entering into environment during post - accident period. This quantity was an average 0.03-0.30 kBq/m2 (with correction on radionuclides decay). The observation for the state of the soil cover includes the estimate of the level and peculiarities of distribution in the soils of heavy metals and microelements. Their content in the soils is formed from Clarke number and additional industrial gas-aerosol fallout. The analysis of a large volume data permitted to calculate the maximal level of the elements content in a soil under influence only natural factors. It was established, that maximal content of Co, Zn, Mn in these soils exceed of their Clarke's numbers. Minimal elements content was found for a tree fall. As a rule, this content is by factor of 10-100 lower than the Clarke values. Maximal concentration is in the soil layer. At the same time the additional technogenic fall-out produces the double increasing of the content of Cu and Pb in the soil layer. For the rest elements the concentrations increased on 8-32%. Acknowledgements. This work was supported by the grant for integrative research between the Ural and Far Eastern Branches of the Russian Academy of Sciences (12-C-4-1001).

  15. Use of LANDSAT images of vegetation cover to estimate effective hydraulic properties of soils

    NASA Technical Reports Server (NTRS)

    Eagleson, Peter S.; Jasinski, Michael F.

    1988-01-01

    This work focuses on the characterization of natural, spatially variable, semivegetated landscapes using a linear, stochastic, canopy-soil reflectance model. A first application of the model was the investigation of the effects of subpixel and regional variability of scenes on the shape and structure of red-infrared scattergrams. Additionally, the model was used to investigate the inverse problem, the estimation of subpixel vegetation cover, given only the scattergrams of simulated satellite scale multispectral scenes. The major aspects of that work, including recent field investigations, are summarized.

  16. Combined effects of precipitation and air temperature on soil moisture in different land covers in a humid basin

    NASA Astrophysics Data System (ADS)

    Feng, Huihui; Liu, Yuanbo

    2015-12-01

    Soil moisture is a key variable in hydrological processes. Although the combined effects of multiple climatic factors in different land cover conditions are highly valuable for water resource management, a complete understanding of these effects remains unclear. This study used a cluster analysis approach to investigate the combined effects of precipitation and air temperature, rather than a single factor, in different land covers for an area over the Poyang Lake Basin in China from 2003 to 2009. Specifically, monthly soil moisture was classified into eight clusters according to the change in precipitation and air temperature; the clusters describe a range of climates from the extreme of wet-hot to that of dry-cold. For an individual climate factor, our results showed that the contribution of air temperature to soil moisture is greater than that of precipitation, and the effect of air temperature is more sensitive in different land covers. When considering the combined effects of precipitation and air temperature, soil moisture varies with land cover; however, the variation in a normal climate cluster is greater than in an extreme climate cluster. This indicated that land cover is the dominant factor in soil moisture variation in normal climatic conditions, whereas climate is the dominant factor in extreme conditions. As climate shifts from the wet-hot to the dry-cold cluster, soil moisture decreases for all land covers, with the minimum rate occurring in forest conditions. Meanwhile, soil moisture deficit and saturation are more likely to occur in grassland and forest areas, indicating that forest cover might mitigate drought. The results of this study provide an effective approach to investigate the combined effects of climate factors on soil moisture for various land covers in humid areas. This study also supports the management of water resources in changing climates.

  17. Conservation tillage, rotations, and cover crop affect soil quality in the Tennessee Valley: Particulate organic matter, organic matter, and microbial biomass

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Monocropping cotton (Gossypium hirsutum L.) with conventional tillage provides little carbon input to soil, increases erosion and promotes rapid oxidation of existing soil organic carbon (SOC). Management practices like conservation tillage, crop rotation, and cover cropping can impact soil carbon, ...

  18. Appendix E: Research papers. Analysis of landfills with historic airphotos

    NASA Technical Reports Server (NTRS)

    Liang, T.; Philipson, W. R. (principal investigators); Erb, T. L.; Teng, W. L.

    1980-01-01

    The nature of landfill-related information that can be derived from existing, or historic, aerial photographs, is reviewed. This information can be used for conducting temporal assessments of landfill existence, land use and land cover, and the physical environment. As such, analysis of low cost, readily available aerial photographs can provide important, objective input to landfill inventories, assessing contamination or health hazards, planning corrective measures, planning waste collection and facilities, and developing on inactive landfills.

  19. Impact of cover crops on soil coservation in olive orchards under different agroecological conditions combing a conceptual soil water balance model (WABOL) and RUSLE.

    NASA Astrophysics Data System (ADS)

    Uran, A.; Lorite, I.; Gomez, J. A.

    2012-04-01

    The effect of cover crops on soil conservation in olive orchards is evaluated based on a limited set of experiments based on runoff plots and model analysis on erosion models. However, the development of cover crops in olive growing areas is strongly controlled by the climate and soil conditions. These conditions are not completely represented in the empirical approach based on runoff plots, while in the modelling analysis approach (e.g. Gómez at Giráldez, 2009) it is usually necessary to make assumptions on the development of the cover crops to calibrate the erosion models that are poorly understood, such as for instance growing ob biomass and ground cover in areas significant colder or driers that those found in the literature, or its impact on the soil water balance. This communications presents a preliminary evaluation of the impact of cover crops in soil conservation in olive growing areas of Andalusia characterized y different soil, and climate conditions. The basic information has been taken from a recent study at national level (Hrnández, M.P., 2011) from which eight different growing areas characterized by different pluviometric and thermic regimes and soil conditions were selected. For those eight areas annual simulations of soil water content for an standard olive grove at 10x10 m under two different soil management techniques: cover crops with two option of cover crop killing in early or late spring; and conventional tillage, were simulated for a 8 to 10 year period based on a recently developed soil water balance model (WABOL, Abazi et al., 2012) which includes development of the cover crop. These results were used to calibrate RUSLE using the methodology proposed by Gómez et al. (2003) including the effect of different ground cover varying according to the conditions of different zones or climate of a particular year. The results of the simulations were used to compare the impact of the cover crop used in different areas on overall erosion risk and in soil water balance when the soil and climate variability (spatial and inter-annual) is included. The provide guidelines to adaption of cover crop management to the local conditions, although further analysis need to be made to include a broader range of conditions and the impact of irrigation.

  20. The influence of soil type, vegetation cover and soil moisture on spin up behaviour of a land surface model in a monsoonal region

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Anwesha; Mandal, Manabottam

    2015-04-01

    Model spin-up is the process through which the model is adequately equilibrated to ensure balance between the mass fields and velocity fields. In this study, an offline one dimensional Noah land surface model is integrated recursively for three years to assess its spin-up behavior at different sites over the Indian Monsoon domain. Several numerical experiments are performed to investigate the impact of soil category, vegetation cover, initial soil moisture and subsequent dry or wet condition on model spin-up. These include simulations with the dominant soil and vegetation covers of this region, different initial soil moisture content (observed soil moisture; dry soil; moderately wet soil; saturated soil), simulations initialized at different rain conditions (no rain; infrequent rain; continuous rain) and different seasons (Winter, Spring, Summer/Pre-Monsoon, Monsoon and Autumn). It is seen that the spin-up behavior of the model depends on the soil type and vegetation cover with soil characteristics having the larger influence. Over India, the model has the longest spin-up in the case of simulations with loamy soil covered with mixed-shrub. It is noted that the model has a significantly longer spin-up when initialized with very low initial soil moisture content than with higher soil moisture content. It is also seen that in general, simulations initialized just before a continuous rainfall event have the least spin-up time. This observation is reinforced by the results from the simulations initialized in different seasons. It is seen that for monsoonal region, the model spin-up time is least for simulations initialized just before the Monsoon. Model initialized during the Monsoon rain episodes has a longer spin-up than that initialized in any other season. Furthermore, it is seen that the model has a shorter spin-up if it reaches the equilibrium state predominantly via drying process and could be as low as two months under quasi-equilibrium condition depending on the time of initialization.

  1. Long term tillage, cover crop and fertilization effects on microbial community structure and activity: Implications on soil quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Reduced tillage, cover crops and fertilization are associated with greater microbial biomass and activity that are linked to improvements in soil quality, but their impacts vary widely with climate, soils and cropping systems. This study aimed to characterize the impact of long term (31 years) tilla...

  2. ACCUMULATION AND CROP UPTAKE OF SOIL MINERAL NITROGEN AS INFLUEMCED BY TILLAGE, COVER CROPS, AND NITROGEN FERTILIZATION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil and crop management practices may influence soil mineral N, crop N uptake, and N leaching. We evaluated the effects of three tillage practices [no-till (NT), strip till (ST), and chisel till (CT)], four cover crops {legume [hairy vetch (Vicia villosa Roth)], nonlegume [rye (Secaele cereale L.)]...

  3. Microbial community structure and abundance in the rhizosphere and bulk soil of a tomato cropping system that includes cover crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this report we use Terminal Restriction Fragment Length Polymorphisms (TRFLP) in a tomato production system to “finger printing” the soil microbial community structure with Phylum specific primer sets. Factors influencing the soil microbes are a cover crop of Hairy Vetch (Vicia villosa) or Rye (...

  4. Cover crops and sampling date effect on on-farm soil carbon pools under conservation tillage cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Cover crops may influence soil C sequestration and microbial activities by providing additional residue C to soil. We examined the influence of legume (crimson clover), nonlegume (rye), blend (a mixture of legumes containing balansa clover, hairy vetch, and crimson clover], and rye + blend mixture c...

  5. Cover crops tillage and glyphosate effects on chemical and biological properties of a Lower Mississippi Delta soil and soybean yield

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The adoption of sustainable cropping systems, including cover crops and no-tillage practices can promote soil conservation and improve soil quality. However, the selection of the best management practices to increase crop production is needed. A field study was conducted from 2001 to 2005 at Stone...

  6. Electromagnetic wave scattering from vegetation (Potato) and vegetation covered soil moisture for remote sensing

    NASA Astrophysics Data System (ADS)

    Singh, Keshev

    In the country with limited resources, where the nutrition level of the population has to be maintained under inhospitable situation, the potato has a special value as food. Therefore efforts should be made for improvement and spreading the cultivation of this important crop. It demands an effective program that may provide information about potato growing areas and the growth conditions. Remote sensing has been acknowledged to be a valuable source of spatially comprehensive and temporally repeatable information of crop covered soil moisture, crop growth climatic information etc, which is useful and necessary for agriculture purposes. For this purpose, microwave remote sensing has evolved as an important tool. Since microwave are able to penetrate more deeply into vegetation and underneath ground surface. It is also preferred to the optical frequency band because microwave can work in all type of weather and have a wide signal dynamic range compared optical wavelengths. However interpretation of microwave scattering from agricultural crops requires an understanding the interaction among microwave, vegetative material and the soil. In order to develop useful forward and inverse models for retrieving the vegetation characteristic, it is necessary to know in detail the dielectric properties and plant structure of the vegetation over the range of expected growing conditions. In this paper, a theoretical model based on microwave interaction with potato crop along with examination of biomass of potato crop with the varying underlying soil moisture is studied. For this purpose, X-band (9.5GHz) scatterometer is used for studying the interaction of microwave with potato crop biomass and underlying soil moisture at various sensor parameters (i.e. angular variation and polarization, HH- and VV-). Although there may be a lot of crop parameters (i.e. crop height, leaf area index, etc) which also gives their effect on microwave. All this parameters are interlinked in the crop. So, this study is focused on biomass, which is one of the main parameter of crop and related with dielectric. Scattering coefficient at X-band showed strong sensitivity to different growth cycle of potato. The soil effect on scattering coefficient was prominent at steeper incidence angle (less than 40 degree) where as potato plant effects are more dominant at higher incidence angle (more than 40 degree). The microwave response of potato is polarization dependent and is more prominent for VV-Pol than HH-Pol at every stages of growth of potato and this strong polarization dependence can play a strong role for crop discrimination. The dependency of scattering coefficient on biomass is statistically checked by the linear regression analysis and results of regression analysis confirm the experimental results i.e., scattering coefficient increases as the biomass increases in the potato crop. The best angle to observe and retrieve the biomass by scattering coefficient is 55 degree and 60 degree incidence angles for HH-Pol and VV-Pol respectively. The regression results also revealed that scattering coefficient is positively correlated with soil moisture for both like pols. This result follows many earlier findings. The best incidence angle to compute the potato covered soil moisture from scattering coefficient is 35 degree and 30 degree for HH- and VV-Pol respectively. The HH- pol has edge over VV-pol for observing the potato the covered soil moisture. This approach provides a new direction to understand the potato scattering at X-band for remote sensing.

  7. Quantitative analysis of physical and geotechnical factors affecting methane emission in municipal solid waste landfill

    NASA Astrophysics Data System (ADS)

    Tecle, Dawit; Lee, Jejung; Hasan, Syed

    2009-01-01

    The amount of methane that vent from landfills is dependent on the physical, chemical and biological components of the soil cover. Especially moisture content and temperature of the soil are known as the major controlling factors. In situ moisture content measurement is very critical because the moisture content of the soil continuously changes within minutes to hours as a result of change in temperature. The presented study used time domain reflectometry to measure in situ moisture content and analyzed moisture content, temperature and methane data of the landfill soil cover in a quantitative manner. Geotechnical factors including soil grain size and uniformity coefficient of the soil were analyzed and their influence on moisture content and methane emission was examined. The authors used kriging and polynomial regression methods to characterize the spatial distribution of moisture content and methane emission. Methane emission showed good temporal correlation with soil temperature, however, no significant relationship between moisture content and methane emission was observed. Spatial distribution of soil attributes was also analyzed to examine its effect on those variables. The spatial pattern of moisture content was quite similar to that of uniformity coefficient, C u and that of clay content of the soil but strongly contrasted to that of methane emission.

  8. Effect of plant cover on distribution of soil organic matter pools

    NASA Astrophysics Data System (ADS)

    Gunina, Anna; Kuzyakov, Yakov; Ryzhova, Irina

    2013-04-01

    Numerous studies reported that quality and quantity of primary production and also the rate of litter decomposition determine the carbon (C) content and its distribution in soils. Our objective was to examine how the type of plant cover affects C sequestration in the following pools: unprotected, spatial inaccessible, interacting with silt and clay, and biochemically protected SOM. The large lysimeters of Moscow State University allowed quantification of C stocks under broadleaf forest (Acer platanoides and Quercus robur), coniferous forest (Picea abies) and agricultural crops (9-field rotation), while other soil forming factors affecting SOC content were identical. In 1965 the lysimeters (S=9 m2, depth=1.5 m) were filled with carbonate free clay loam taken in Moscow region, originated from the Valday glaciation, and plant communities listed above were planted. We collected soil samples from the mineral horizons, from 0-5 cm depth, in spring 2012. The soils were physically separated by combination of the particle size and density fractionations (8 fractions in total), and C and N contents were analyzed. The total C and N contents in non-fractionated soil were higher under broadleaf forest (66 and 3.1 g kg-1), than under coniferous forest (34.5 and 1.23 g kg-1) and agricultural crops (13.7 and 0.9 g kg-1). Under forests 45-50% of Ctotal and 30% of Ntotal were in the unprotected pool, in agricultural soil these percentages were in 3 times less. The greatest portions of protected C were in spatial inaccessible pool: 28, 32 and 40% of the Ctotal for broadleaf forest, coniferous forest and agricultural crops, respectively. However, the total C amount in this pool under agricultural crops was in 3 times less, than under forests. This is indicative for the loss of C-rich macroaggregates and an increase of C-depleted microaggregates in agricultural soils due to the plowing. The amounts of C, stabilized by interactions with silt and clay, were nearly the same (3-6 g kg-1) because of the identical texture of soil parent material. The portion of biochemically protected C was maximal in agricultural soil - 27%, whereas on forest plots it was 2 times less. The amount of C in this pool did not strongly differ among the investigated soils, but C/N ratio was lower under agricultural crops than under forests. This indicates deeper degradation of organics in cultivated soil, N addition by fertilization, and a growing contribution of microbially-derived C to the biochemically protected pool. Wide C/N ratio in biochemically protected pool in the forest soils reflects the accumulation of primary recalcitrant plant substances with high C/N such as lignin and cellulose. Thus, forest vegetation contributes mainly to the SOM sequestration in the spatial inaccessible pool and is source of the high amount of non-protected C. Under agricultural crops however, the most of SOM is stabilized by interactions with silt and clay and is stabilized biochemically.

  9. Feasibility of using LANDSAT images of vegetation cover to estimate effective hydraulic properties of soils

    NASA Technical Reports Server (NTRS)

    Eagleson, P. S.

    1985-01-01

    Research activities conducted from February 1, 1985 to July 31, 1985 and preliminary conclusions regarding research objectives are summarized. The objective is to determine the feasibility of using LANDSAT data to estimate effective hydraulic properties of soils. The general approach is to apply the climatic-climax hypothesis (Ealgeson, 1982) to natural water-limited vegetation systems using canopy cover estimated from LANDSAT data. Natural water-limited systems typically consist of inhomogeneous vegetation canopies interspersed with bare soils. The ground resolution associated with one pixel from LANDSAT MSS (or TM) data is generally greater than the scale of the plant canopy or canopy clusters. Thus a method for resolving percent canopy cover at a subpixel level must be established before the Eagleson hypothesis can be tested. Two formulations are proposed which extend existing methods of analyzing mixed pixels to naturally vegetated landscapes. The first method involves use of the normalized vegetation index. The second approach is a physical model based on radiative transfer principles. Both methods are to be analyzed for their feasibility on selected sites.

  10. Dynamics of non-Controlled Emission of Biogas From Landfills

    NASA Astrophysics Data System (ADS)

    Lima, R.; Salazar, J.; Hernandez, P.; Perez, N.

    2001-12-01

    Landfills are important sources of CH4 and CO2 as well as other toxic gas components to the atmosphere. A significant amount of gases could be released to the surrounding environment as a "non-controlled" emission in a diffuse form. To understand the dynamics of non-controlled emission of biogas from landfills several soil gas and CO2 efflux surveys were performed at Arico's landfill (Tenerife, Canary Islands). Estimated diffuse CO2 emission for Arico's landfill (0.33 Km2) were 507 td-1 (1998) and 131 td-1 (2000), showing different spatial CO2 efflux patterns that can be explained in terms of new waste disposal and covering materials as well as the action of the biogas extraction system. Secular variations of diffuse CO2 efflux and meteorological and soil variables were measured hourly at one site in the center of the landfill for 11 months. Diffuse CO2 efflux ranged from 9.9 to 433.3 gm-2d^{-1} with a median value of 242.7 \\pm 73.3 gm^{-2}d-1. Diffuse CO2 efflux showed a temporal behavior that could be divided in two different periods: (a) a quasi-stationary period with minor fluctuations due to the influence of meteorological and soil variables, and (b) a non-stationary period with changing CO2 efflux level and major variations related to the preliminary tests on the biogas extraction system for Arico's landfill. Air and ground temperatures exhibit significant positive correlation with the observed CO2 efflux. Peaks of maximum inverse correlation between barometric pressure and CO2 efflux are found at semi-diurnal and diurnal frequencies. Wind speed and wind direction are cross-correlated with CO2 efflux by 12 hours. These results suggest that (i) minor fluctuations in the CO2 efflux could be driven by meteorological variations (solar radiation cycles and local wind patterns), and (ii) sudden and major fluctuations in the CO2 efflux cannot be explained sufficiently in terms of the observed meteorological and soil variables' fluctuations.

  11. Carbon supply and storage in tilled and non-tilled soils as influenced by cover crops and nitrogen fertilization

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The influence of four cover crops (hairy vetch, rye, biculture of vetch and rye, and winter weeds)and three N fertilization rates (0, 60 to 65, and 120 to 130 kg N ha-1) was examined on plant C input from cover crops, cotton, and sorghum and soi organic C (SOC) in tilled and non-tilled soils in cent...

  12. Can cover crop and manure maintain or improve soil properties after stover removal from irrigated no-till corn?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Addition of cover crops and animal manure following corn (Zea mays L.) stover removal for expanded uses may mitigate negative soil property effects of stover removal. We studied the short-term (3 yr) cumulative impacts of stover removal with and without winter rye (Secale cereale L.) cover crop or a...

  13. Species-diversified plant cover enhances orchard ecosystem resistance to climatic stress and soil erosion in subtropical hillside*

    PubMed Central

    Chen, Xin; Yang, Yi-song; Tang, Jian-jun

    2004-01-01

    Naturally occurring plants in agroecosystem evidently play an important role in ecosystem stability. Field studies on the ecological effects of native plants conserved in orchard and their resistance to adverse climatic stress, and soil erosion were conducted from 1998 to 2001 in a newly developed Changshan-huyou (Citrus changshan-huyou Y.B. Chang) orchard. The experimental area covered 150 ha in typical red soil hilly region in southeastern China. The experimental design was a randomized complete block with six combinations of twelve plant species with four replications. All species used were native in the orchard. Plots were 158 m2 and separated by 2 m buffer strips. Precipitation, soil erosion in rainstorm days and aboveground biomass of plant community when rainstorm days ended, soil temperature and moisture under various plant covers during seasonal megathermal drought period, antiscourability of soil with different root density under various simulated rainfalls were measured. Plant cover significantly decreased the daily highest and mean soil temperature and its daily variation in hot-drought season, but there was no significant difference of the alleviation among various plant covers. Plant covers significantly increased the soil moisture in seasonal megathermal drought period. Better moisture maintenance and soil erosion reduction was found when the plant species numbers in cover plant communities increased from one to eight. Higher root density in plant communities with higher species richness increased significantly the antiscourability of the soil. It was suggested that conserving plant communities with diversified native species could produce the best positive ecological effects on citrus orchard ecosystem stability. PMID:15362189

  14. Bowen ratio measurements above various vegetation covers and its comparison with actual evapotranspiration estimated by SoilClim model

    NASA Astrophysics Data System (ADS)

    Hlavinka, P.; Trnka, M.; Fischer, M.; Kucera, J.; Mozny, M.; Zalud, Z.

    2010-09-01

    The principle of Bowen ratio is one of the available techniques for measurements of actual evapotranspiration (ETa) as one of essential water balance fractions. The main aims of submitted study were: (i) to compare the water balance of selected crops, (ii) to compare outputs of SoilClim model with observed parameters (including ETa on Bowen ratio basis). The measurements were conducted at two experimental stations in the Czech Republic (Polkovice 49°23´ (N), 17°17´ (E), 205 m a.s.l.; Domanínek 49°32´ (N), 16°15´ (E), 544 m a.s.l.) during the years 2009 and 2010. Together with Bowen ratio the global solar radiation, radiation balance, soil heat flux, volumetric soil moisture and temperature within selected depths, precipitation and wind speed were measured. The measurements were conducted simultaneously above various covers within the same soil conditions: spring barley vs. winter wheat, spring barley vs. winter rape; grass vs. poplars; harvested field after tillage vs. harvested field after cereals without any tillage. The observed parameters from different covers were compared with SoilClim estimates. SoilClim model is modular software for water balance and soil temperature modelling and finally could be used for soil Hydric and Thermic regimes (according to USDA classification) identification. The core of SoilClim is based on modified FAO Penman-Monteith methodology. Submitted study proved the applicability of SoilClim model for ETa, soil moisture within two defined layers and soil temperature (in 0.5 m depth) estimates for various crops, covers, selected soil types and climatic conditions. Acknowledgement: We gratefully acknowledge the support of the Grant Agency of the Czech Republic (no. 521/09/P479) and the project NAZV QI91C054. The study was also supported by Research plan No. MSM6215648905 "Biological and technological aspects of sustainability of controlled ecosystems and their adaptability to climate change".

  15. Fate and Transport of Pharmaceutical Compounds Applied to Turf-Covered Soil

    NASA Astrophysics Data System (ADS)

    Young, M.; Green, R. L.; Devitt, D.; McCullough, M.; Wright, L.; Vanderford, B. J.; Snyder, S. A.

    2012-12-01

    In arid and semi-arid regions, the use of treated wastewater for landscape irrigation is becoming common practice and a significant asset to conserve potable water supplies. Public interest and lack of field-scale data are leading to a concern that compounds found in reuse water could persist in the environment and contaminate groundwater. As part of a larger study, 2-yr experiments were conducted in CA and NV, where reuse water was the primary source of non-ambient water input. A total of 13 compounds were studied, all originating in irrigation water applied to soil covered in turf or left bare. The target compounds included atenolol, atorvastatin, carbamazepine, diazepam, diclofenac, fluoxetine, gemfibrozil, ibuprofen, meprobamate, naproxen, primidone, sulfamethoxazole, triclosan, and trimethoprim. Analytical protocols for all compounds (detection at ng/L range) were established before the study commenced. The goals of the research were to increase available data on the fate and transport of these target compounds in turfgrass/soil systems, and to use these data to assess long-term risk from using water containing these compounds. Experiments conducted at two scales are discussed here: lysimeter-scale and field-scale. At the lysimeter-scale, 24 drainage lysimeters (120 cm thick) were exposed to treated wastewater as an irrigation source. Lysimeters varied by soil type (two types), soil cover (bare- versus turf-covered) and leaching fraction (5% and 25%). Upper and lower boundary conditions were monitored throughout the study. Water samples were collected periodically after water breakthrough. After the study, soil samples were analyzed for compound mass, allowing compound mass balance and removal to be assessed. At the field-scale, passive drain gages (Decagon Devices) were installed in triplicate in fairways at four operational golf courses, one in NV and three in CA, all with histories of using treated wastewater. The gages measure water fluxes through the 60-cm thick column and store water for subsequent sampling and analysis. Irrigation water was sampled and analyzed for input mass. Using output mass, removal efficiencies could also be assessed. Results of the lysimeter study showed that mass fluxes were reduced to less than 1 g/ha/yr for all compounds (sulfamethoxazole was highest at 0.25 g/ha/yr). Solute breakthrough was concentrated during fall and winter periods when turf was overseeded and sites received winter precipitation. Results of the golf course study were similar, showing scalability. We report more than 100 instances of target compounds detected in water that percolated through the turf and upper 60 cm of soil, but with total mass fluxes of <0.1 g/ha throughout the study. Sulfamethoxazole, meprobamate, and carbamazepine were most commonly found in drainage water, but gemfibrozil, diclofenac, naproxen, and triclosan were also found in more than one sample. The results allowed for a preliminary risk assessment to be conducted. Based on our results, restricting the use of recycled water, based solely on the presence of PPCPs should only be considered at sites where soils are extremely sandy and irrigation regimes are not based on an evapotranspiration feedback approach.

  16. Mixed Waste Landfill Integrated Demonstration; Technology summary

    SciTech Connect

    1994-02-01

    The mission of the Mixed Waste Landfill Integrated Demonstration (MWLID) is to demonstrate, in contaminated sites, new technologies for clean-up of chemical and mixed waste landfills that are representative of many sites throughout the DOE Complex and the nation. When implemented, these new technologies promise to characterize and remediate the contaminated landfill sites across the country that resulted from past waste disposal practices. Characterization and remediation technologies are aimed at making clean-up less expensive, safer, and more effective than current techniques. This will be done by emphasizing in-situ technologies. Most important, MWLID`s success will be shared with other Federal, state, and local governments, and private companies that face the important task of waste site remediation. MWLID will demonstrate technologies at two existing landfills. Sandia National Laboratories` Chemical Waste Landfill received hazardous (chemical) waste from the Laboratory from 1962 to 1985, and the Mixed-Waste Landfill received hazardous and radioactive wastes (mixed wastes) over a twenty-nine year period (1959-1988) from various Sandia nuclear research programs. Both landfills are now closed. Originally, however, the sites were selected because of Albuquerque`s and climate and the thick layer of alluvial deposits that overlay groundwater approximately 480 feet below the landfills. This thick layer of ``dry`` soils, gravel, and clays promised to be a natural barrier between the landfills and groundwater.

  17. The Future Through the Past: The Use of Analog Sites for Design Criteria and Long Term Performance Assessment of Evapotranspiration Landfill Covers

    SciTech Connect

    Shafer, D. S.; Miller, J. J.; Young, M. H.; Edwards, S. C.; Rawlinson, S. E.

    2002-02-26

    There is growing support for using evapotranspiration (ET) covers for closure of low-level waste (LLW) and other types of waste disposal sites, particularly in the lower latitude arid regions of the western United States. At the Nevada Test Site (NTS), monolayer ET covers are the baseline technology for closure of LLW and mixed LLW cells. To better predict the long-term performance of monolayer ET covers, as well as to identify design criteria that will potentially improve their performance, the properties of, and processes occurring on, analog sites for ET covers on the NTS are being studied. The project is funded through the Subsurface Contaminants Focus Area of the U.S. Department of Energy. Four analog sites on the NTS have been selected to predict performance of ET covers over a 1,000-year compliance period. Two sites are relatively recently disturbed (within the last 50 years) and have been selected to evaluate processes and changes on ET covers for the early period after active cover maintenance is discontinued. Two other sites, late to mid-Holocene in age, are intended as analogs for the end of the compliance period (1,000 years or more); both surfaces are abandoned alluvial/colluvial deposits. The history of the early post-institutional control analog sites are being evaluated by an archaeologist to help determine when the sites were last disturbed or modified, and the mode of disturbance to help set baseline conditions. Similar to other ''landforms,'' ET covers will evolve over time because of pedogenic, biotic, and climatic processes. Properties of analog sites that could affect ET water balance performance will be evaluated to help understand ET cover performance over time.

  18. Cleaner Landfills

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Osmotek, Inc. developed the Direct Osmosis treatment system through SBIR funding from Ames Research Center. Using technology originally developed for flight aboard the Space Station, the company brought it to their commercial water purification treatment system, Direct Osmosis. This water purification system uses a direct osmosis process followed by a reverse osmosis treatment. Because the product extracts water from a waste product, Osmotek is marketing the unit for use in landfills. The system can treat leachate (toxic chemicals leached into a water source), by filtering the water and leaving behind the leahcate. The leachate then becomes solidified into substance that can not seep into water.

  19. The future through the past: The use of analog sites for design criteria and long-term performance assessment of evapotranspiration landfill covers.

    SciTech Connect

    David Shafer; Julianne Miller; Susan Edwards; Stuart Rawlinson

    2001-10-18

    There is growing support for using evapotranspiration (ET) covers for closure of low-level waste (LLW) and other types of waste disposal sites, particularly in the lower latitude arid regions of the western United States. For the Nevada Test Site (NTS), monolayer ET covers is the baseline technology for closure of LLW and mixed LLW cells. To better predict the long-term performance of monolayer ET covers, as well as to identify design criteria that will potentially improve their performance, the properties of, and processes occurring on, analog sites for ET covers on the NTS are being studied. Four analog sites on the NTS have been selected to predict performance of ET covers over a 1,000-year compliance period. Two are relatively recently disturbed sites (within the last 50 years) and have been selected for the evaluation of processes and changes on ET covers for the early period of post-institutional controls when cover maintenance would be discontinued. Two other sites, late to mid-Holocene in age, are intended as analogs for the end (1,000 years or more) of the compliance period. The late to mid-Holocene surfaces are both abandoned alluvial/colluvial deposits, dated by thermoluminescence analysis. The history of the early post-institutional control analog sites is being evaluated by an archaeologist to help determine when the sites were last disturbed or modified and the mode of disturbance, to help set baseline conditions. Similar to the other ''landforms,'' ET covers will evolve over time because of pedogenic, biotic, and climatic processes. Properties of analog sites that could affect ET water-balance performance will be evaluated to help understand ET cover performance over time. Results of analog site work and resultant modifications to design, monitoring and maintenance of ET covers on the NTS will be compared with results of a similar study being done at Sandia National Laboratories (SNL), where ET cover closures are planned as well. The comparison will help to distinguish potential regional differences needed in ET cover design. Although both sites are at similar latitudes, the NTS is located in a transition zone between the Mojave and southern Great Basin deserts, while SNL is located in the northern Chihuahuan desert. Differences in vegetation and seasonality of precipitation between the sites are significant.

  20. Organic Carbon and Nitrogen Storages of Soils Covering Yedoma Deposits in the Lena River Delta

    NASA Astrophysics Data System (ADS)

    Zubrzycki, Sebastian; Kutzbach, Lars; Morgenstern, Anne; Grosse, Guido; Pfeiffer, Eva-Maria

    2014-05-01

    The Lena River Delta (LRD) is located in northeast Siberia and extends over a soil covered area of around 21,500 km2. LRD likely stores more than half of the entire soil organic carbon (SOC) mass stored in deltas affected by permafrost. LRD consists of several geomorphic units. Recent studies showed that the spatially dominating Holocene units of the LRD (61 % of the area) store around 240 Tg of SOC and 12 Tg of nitrogen (N) within the first meter of ground. These units are a river terrace dominated by wet sedge polygons and the active floodplains. About 50 % of these reported storages are located in the perennially frozen ground below 50 cm depth and are excluded from intense biogeochemical exchange with the atmosphere today. However, these storages are likely to be mineralised in near future due to the projected temperature increases in this region. A substantial part of the LRD (1,712 km2) belongs to the so-called Yedoma Region, which formed during the Late Pleistocene. This oldest unit of the LRD is characterised by extensive plains incised by thermo-erosional valleys and large thermokarst depressions. Such depressions are called Alases and cover around 20 % of the area. Yedoma deposits in the LDR are known to store high amounts of SOC. However, within the LRD no detailed spatial studies on SOC and N in the soils overlying Yedoma and thermokarst depressions were carried out so far. We present here our 'investigation in progress' on soils in these landscape units of the LRD. Our first estimates, based on 69 pedons sampled in 2008, show that the mean SOC stocks for the upper 30 cm of soils on both units were estimated at 13.0 kg m2 4.8 kg m2 on the Yedoma surfaces and at 13.1 kg m2 3.8 kg m2 in the Alases. The stocks of N were estimated at 0.69 kg m2 0.25 kg m2and at 0.70 kg m2 0.18 kg m2 on the Yedoma surfaces and in the Alases, respectively. The estimated SOC and N pools for the depth of 30 cm within the investigated part of the LRD add to 20.9 Tg and 1.1 Tg, respectively. The Yedoma surfaces (1,313 km2) store 17.1 6.3 Tg SOC and 0.9 0.3 Tg N, whereas the Alases (287 km2) store 3.8 1.1 Tg SOC and 0.2 0.05 Tg N within the investigated depth of 30 cm. Further analyses of the soil core material collected in 2013 will provide SOC and N pool estimates for a depth of 100 cm including both, the seasonally active layer and the perennially frozen ground. With continuing advanced analyses of an available digital elevation model, slopes will be designated with their extents and inclinations since the planar extents of slopes derived from satellite imagery do not correspond to the actual slope soil surface area, which is vital for spatial SOC and N storage calculations as well as trace gas release estimates. The actual soil surface area of slopes will be calculated prior to result extrapolations.

  1. The Effect of Leaf Litter Cover on Surface Runoff and Soil Erosion in Northern China

    PubMed Central

    Li, Xiang; Niu, Jianzhi; Xie, Baoyuan

    2014-01-01

    The role of leaf litter in hydrological processes and soil erosion of forest ecosystems is poorly understood. A field experiment was conducted under simulated rainfall in runoff plots with a slope of 10%. Two common types of litter in North China (from Quercus variabilis, representing broadleaf litter, and Pinus tabulaeformis, representing needle leaf litter), four amounts of litter, and five rainfall intensities were tested. Results revealed that the litter reduced runoff and delayed the beginning of runoff, but significantly reduced soil loss (p<0.05). Average runoff yield was 29.5% and 31.3% less than bare-soil plot, and for Q. variabilis and P. tabulaeformis, respectively, and average sediment yield was 85.1% and 79.9% lower. Rainfall intensity significantly affected runoff (R = 0.99, p<0.05), and the efficiency in runoff reduction by litter decreased considerably. Runoff yield and the runoff coefficient increased dramatically by 72.9 and 5.4 times, respectively. The period of time before runoff appeared decreased approximately 96.7% when rainfall intensity increased from 5.7 to 75.6 mm h−1. Broadleaf and needle leaf litter showed similarly relevant effects on runoff and soil erosion control, since no significant differences (p≤0.05) were observed in runoff and sediment variables between two litter-covered plots. In contrast, litter mass was probably not a main factor in determining runoff and sediment because a significant correlation was found only with sediment in Q. variabilis litter plot. Finally, runoff yield was significantly correlated (p<0.05) with sediment yield. These results suggest that the protective role of leaf litter in runoff and erosion processes was crucial, and both rainfall intensity and litter characteristics had an impact on these processes. PMID:25232858

  2. Assessing methane oxidation under landfill covers and its contribution to the above atmospheric CO{sub 2} levels: The added value of the isotope ({delta}{sup 13}C and {delta}{sup 18}O CO{sub 2}; {delta}{sup 13}C and {delta}D CH{sub 4}) approach

    SciTech Connect

    Widory, D.; Proust, E.; Bellenfant, G.; Bour, O.

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Comparison of the isotope and mass balance approaches to evaluate the level of methane oxidation within a landfill. Black-Right-Pointing-Pointer The level of methane oxidation is not homogenous under the landfill cover and is strongly correlated to the methane flux. Black-Right-Pointing-Pointer Isotope tracking of the contribution of the methane oxidation to the CO{sub 2} concentrations in the ambient air. - Abstract: We are presenting here a multi-isotope approach ({delta}{sup 13}C and {delta}{sup 18}O of CO{sub 2}; {delta}{sup 13}C and {delta}D of CH{sub 4}) to assess (i) the level(s) of methane oxidation during waste biodegradation and its migration through a landfill cover in Sonzay (France), and (ii) its contribution to the atmospheric CO{sub 2} levels above the surface. The isotope approach is compared to the more conventional mass balance approach. Results from the two techniques are comparable and show that the CH{sub 4} oxidation under the landfill cover is heterogenous, with low oxidation percentages in samples showing high biogas fluxes, which was expected in clay covers presenting fissures, through which CH{sub 4} is rapidly transported. At shallow depth, more immobile biogas pockets show a higher level of CH{sub 4} oxidation by the methanotrophic bacteria. {delta}{sup 13}C of CO{sub 2} samples taken at different heights (from below the cover up to 8 m above the ground level) were also used to identify and assess the relative contributions of its main sources both under the landfill cover and in the surrounding atmosphere.

  3. Soil carbon storage as influenced by tree cover in the Dehesa cork oak silvopasture of central-western Spain.

    PubMed

    Howlett, David Scott; Moreno, Gerardo; Mosquera Losada, Maria Rosa; Nair, P K Ramachandran; Nair, Vimala D

    2011-07-01

    The extent of carbon (C) stored in soils depends on a number of factors including soil characteristics, climatic and other environmental conditions, and management practices. Such information, however, is lacking for silvopastoral systems in Spain. This study quantified the amounts of soil C stored at various depths (0-25, 25-50, 50-75, and 75-100 cm) under a Dehesa cork oak (Quercus suber L.) silvopasture at varying distances (2, 5, and 15 m) to trees. Soil C in the whole soil and three soil fractions (<53, 53-250, and 250-2000 μm) was determined. Results showed soil depth to be a significant factor in soil C stocks in all soil particle sizes. Distance to tree was a significant factor determining soil C stocks in the whole soil and the 250-2000 μm soil fraction. To 1 m depth, mean total C storage at 2, 5, and 15 m from cork oak was 50.2, 37, and 26.5 Mg ha(-1), respectively. Taking into account proportions of land surface area containing these C stocks at varying distances to trees to 1 m depth, with a tree density of 35 stems ha(-1), estimated landscape soil C is 29.9 Mg ha(-1). Greater soil C stocks directly underneath the tree canopy suggest that maintaining or increasing tree cover, where lost from disease or management, may increase long term storage of soil C in Mediterranean silvopastoral systems. The results also demonstrate the use of soil aggregate characteristics as better indicators of soil C sequestration potential and thus a tool for environmental monitoring. PMID:21643613

  4. DIFFERENCES IN THE SOIL MICROARTHROPOD COMMUNITY UNDER TWO WINTER COVER CROPS IN STRIP-TILLED COTTON

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is understood that implementing conservation tillage practices will improve soil quality. Increased soil organic matter under conservation tillage supports the development of the soil biotic community. Organic matter quantity and quality influence soil microarthropod abundance and diversity. O...

  5. Linking the planting of cover crops to soil and water nutrient dynamics in Shatto Ditch Watershed, IN

    NASA Astrophysics Data System (ADS)

    Christopher, S. F.; Tank, J. L.; Hanrahan, B. R.; Mahl, U. H.; Huang, K.

    2013-12-01

    Tile drainage systems are common in the Midwest, and facilitate the transfer of excess inorganic nitrogen (N) and phosphorus (P) from agricultural soils to adjacent streams. These non-point sources contribute to elevated nutrient loads to tributaries in the Mississippi River Basin, which have been linked to widespread hypoxia and associated ecological and economic problems in the Gulf of Mexico. In agricultural areas dominated by row-crops, the planting of cover crops after the cash crop has been harvested offers a potential mechanism to reduce nutrient leaching from fields to tile drains in the off-season. In general, cover crops retain nutrients on fields and increase soil organic matter (SOM) content after they are harvested. The planting of cover crops also promotes immobilization of soil N and reduction in losses of dissolved P from soils due to reduced erosion, resulting in significantly less leaching to surface waters through tile drains. As part of a demonstration project in the Shatto Ditch Watershed, located in the Tippecanoe River Basin, IN, we are testing whether the planting of cover crops will influence soil nutrient and organic matter, and how cover crops alter the dynamics of nutrient leaching from tile drains. We have been sampling tile drain outflows on a twice-monthly sampling regime and have been measuring dissolved inorganic N and P concentrations in tile water since November 2012. During Spring 2013, tile drain nitrate concentrations sampled synoptically throughout the watershed ranged from 2.6 - 38.9 mg NO3- L -1 (mean = 17.2 +/- 1.6 mg NO3- L -1) with the lowest concentrations coming from fields planted in cover crops (range = 2.6 - 19.0 mg NO3- L -1, mean = 9.7 +/- 1.5 mg NO3- L -1). In contrast, soluble reactive phosphorus (SRP) concentrations were much lower in tile drain water and ranged from 7.5 - 182.7 μg L-1 (mean = 24.5 +/- 5.0 μg L-1 SRP) and preliminary data suggest that there were no differences between fields with and without cover crops. In July 2012, we also sampled soils for SOM and inorganic N and P, 6 weeks after cover crop planting because the net effects of mineralization, leaching, and other potential losses that may have occurred since the cover crop was harvested are most accurately assessed at this time. Preliminary results suggest SOM content in the near-surface soil layer (i.e., 0 - 5 cm) in 3 fields planted in cover crops were similar (mean = 4.6 % +/- 0.3 %) to the mean SOM across the other 17 fields sampled without cover crops (mean = 5.8 % +/- 0.9 %). Finally, based on nutrient signatures in the tile drain samples, we predict that soil nitrate concentrations will be lower in soils planted with cover crops, but there will be little difference in soil extractable P between cover crop and non-cover crop fields. The combined sampling of both tile water and field soils will help assess whether cover crops provide a management compromise that allows farmers to improve their soil health, while at the same time improving adjacent stream water quality.

  6. Holocene climate evolution, human occupation, soil erosion and vegetation cover change in southeast Spain

    NASA Astrophysics Data System (ADS)

    Bellin, Nicolas; Vanacker, Veerle

    2010-05-01

    The Mediterranean region is commonly reported as the European region that is most affected by soil degradation. The degradation of Mediterranean soils has often been linked to inappropriate agricultural practices during the last decades besides its typical semiarid conditions. The present-day landscape in Southeast Spain is the result of a long occupation history. To have a better understanding of the impact of human societies on soil degradation, the main shifts in vegetation cover, climate and human occupation have to be taken into account. Recently published paleo-environmental data from continental pollen sequences, high-resolution marine cores, and estimations of the past Sea Surface Temperature (SST) of the Alborn Sea provide new insights in the evolution of the Mediterranean climate and vegetation during the Holocene. These data allow overcoming some of the shortcomings of previous studies on the interaction between humans and the landscape that were mainly based on extrapolations of site-specific information from continental deposits and archeological sites and large-scale regional correlations. Our compilation of multi-continental proxies from the Iberic Peninsula indicates that environmental conditions are strongly related to climatic oscillations and strongly correlated with the North Atlantic changes. By use of a vertical approach, several aridification episodes were detected from marine and continental records at 12000-11600 (H), 11100-10800 (G), 10300-9900 (F), 8600-8000 (E), 5500-4600 (D), 4000-3400 (C), 2700-2400 (B), 1800-1300 (A) cal. years BP. The data suggest that those severe aridification phases were most likely climatically induced, not human-driven and well correlated with the Bond events. We observe a clear association between climate, vegetation cover and sediment fluxes for the period from 12000 to 4600 cal. years BP. In contrast, during the last 4600 years, the reconstruction of various eco-historical periods indicated a weak to low association between sediment fluxes and climatic shifts. Periods of improved climatic conditions were associated with both low (end of Post Argaric-Omeya-Nazarene) and high (Chalcolithic-Roman-Early Phoenician I) erosion rates. Various prosperous civilizations (such as Agarics, Phoenicians and Romans) defined by a demographic explosion and associated with an overexploitation of natural resources, are accompanied with higher sediment fluxes. At the moment, we cannot exclude the possibility that the weak association observed between sediment fluxes and human-climatic factors for the last 4600 years is an artifact resulting from the low temporal resolution of soil erosion data from local sites compared to the high-resolution climatic data. It is clear that high-resolution data on sediment fluxes are required to test these hypotheses further.

  7. Sustainable treatment of landfill leachate

    NASA Astrophysics Data System (ADS)

    Kamaruddin, Mohamad Anuar; Yusoff, Mohd. Suffian; Aziz, Hamidi Abdul; Hung, Yung-Tse

    2014-03-01

    Landfill leachate is a complex liquid that contains excessive concentrations of biodegradable and non-biodegradable products including organic matter, phenols, ammonia nitrogen, phosphate, heavy metals, and sulfide. If not properly treated and safely disposed, landfill leachate could be an impending source to surface and ground water contamination as it may percolate throughout soils and subsoils, causing adverse impacts to receiving waters. Lately, various types of treatment methods have been proposed to alleviate the risks of untreated leachate. However, some of the available techniques remain complicated, expensive and generally require definite adaptation during process. In this article, a review of literature reported from 2008 to 2012 on sustainable landfill leachate treatment technologies is discussed which includes biological and physical-chemical techniques, respectively.

  8. Soil respiration and photosynthetic uptake of carbon dioxide by ground-cover plants in four ages of jack pine forest

    USGS Publications Warehouse

    Striegl, R.G.; Wickland, K.P.

    2001-01-01

    Soil carbon dioxide (CO2) emission (soil respiration), net CO2 exchange after photosynthetic uptake by ground-cover plants, and soil CO2 concentration versus depth below land surface were measured at four ages of jack pine (Pinus banksiana Lamb.) forest in central Saskatchewan. Soil respiration was smallest at a clear-cut site, largest in an 8-year-old stand, and decreased with stand age in 20-year-old and mature (60-75 years old) stands during May-September 1994 (12.1, 34.6, 31.5, and 24.9 mol C??m-2, respectively). Simulations of soil respiration at each stand based on continuously recorded soil temperature were within one standard deviation of measured flux for 48 of 52 measurement periods, but were 10%-30% less than linear interpolations of measured flux for the season. This was probably due to decreased soil respiration at night modeled by the temperature-flux relationships, but not documented by daytime chamber measurements. CO2 uptake by ground-cover plants ranged from 0 at the clear-cut site to 29, 25, and 9% of total growing season soil respiration at the 8-year, 20-year, and mature stands. CO2 concentrations were as great as 7150 ppmv in the upper 1 m of unsaturated zone and were proportional to measured soil respiration.

  9. An experimental investigation to characterise soil macroporosity under different land use and land covers of northeast India

    NASA Astrophysics Data System (ADS)

    Shougrakpam, Sangeeta; Sarkar, Rupak; Dutta, Subashisa

    2010-10-01

    Saturated macropore flow is the dominant hydrological process in tropical and subtropical hilly watersheds of northeast India. The process of infiltration into saturated macroporous soils is primarily controlled by size, network, density, connectivity, saturation of surrounding soil matrix, and depthwise distribution of macropores. To understand the effects of local land use, land cover and management practices on soil macroporosity, colour dye infiltration experiments were conducted with ten soil columns (25 25 50 cm) collected from different watersheds of the region under similar soil and agro-climatic zones. The sampling sites included two undisturbed forested hillslopes, two conventionally cultivated paddy fields, two forest lands abandoned after Jhum cultivation, and two paddy fields, one pineapple plot and one banana plot presently under active cultivation stage of the Jhum cycle. Digital image analyses of the obtained dye patterns showed that the infiltration patterns differed significantly for different sites with varying land use, land cover, and cultivation practices. Undisturbed forest soils showed high degree of soil macroporosity throughout the soil profile, paddy fields revealed sealing of macropores at the topsoil due to hard pan formation, and Jhum cultivated plots showed disconnected subsoil macropores. The important parameters related to soil macropores such as maximum and average size of macropores, number of active macropores, and depthwise distribution of macropores were estimated to characterise the soil macroporosity for the sites. These experimentally derived quantitative data of soil macroporosity can have wide range of applications in the region such as water quality monitoring and groundwater pollution assessment due to preferential leaching of solutes and pesticides, study of soil structural properties and infiltration behaviour of soils, investigation of flash floods in rivers, and hydrological modelling of the watersheds.

  10. The influence of vegetation covers on soil moisture dynamics at high temporal resolution in scattered tree woodlands of Mediterranean climate

    NASA Astrophysics Data System (ADS)

    Lozano-Parra, Javier; Schnabel, Susanne; Ceballos-Barbancho, Antonio

    2015-04-01

    Soil water is a key factor that controls the organization and functioning of dryland ecosystems. However, in spite of its great importance in ecohydrological processes, most of the studies focus on daily or longer timescales, while its dynamics at shorter timescales are very little known. The main objective of this work was to determine the role of vegetation covers (grassland and tree canopy) in the soil hydrological response using measurements with high temporal resolution in evergreen oak woodland with Mediterranean climate. For this, soil water content was monitored continuously with a temporal resolution of 30 minutes and by means of capacitance sensors, mainly for the hydrological years 2010-2011 and 2011-2012. They were installed at 5, 10 and 15 cm, and 5 cm above the bedrock and depending on soil profile. This distribution along the soil profile is justified because soils are generally very shallow and most of the roots are concentrated in the upper layer. The sensors were gathered in 8 soil moisture stations in two contrasting situations characterized by different vegetation covers: under tree canopy and in open spaces or grasslands. Soil moisture variations were calculated at rainfall event scale at top soil layer and deepest depth by the difference between the final and initial soil moisture registered by a sensor at the finish and the beginning of the rainfall event, respectively. Besides, as soil moisture changes are strongly influenced by antecedent conditions, different antecedent soil moisture conditions or states, from driest to wettest, were also defined. The works were carried out in 3 experimental farms of the Spanish region of Extremadura. Results obtained revealed that rainwater amount bypassing vegetation covers and reaching the soil may temporarily be modified by covers according to precipitation properties and antecedent environmental conditions (from dry to wet) before the rain episode. Rainfall amounts triggering a positive soil hydrological response decreased as initial states became drier, being more accentuated below tree canopies. The frequency of the antecedent states seem to be as important or even more than duration or precipitation amount. The role of vegetation was more decisive under drier environmental conditions, where events lower than 6 mm and 2 mm never caused soil hydrological response either below tree canopy or grassland, respectively. This is important because initial conditions were independent of seasonality and because more than half of all rainfall events registered amounts smaller than 5 mm. If changes on temperature regime or precipitation patterns turn out in drier conditions, dry spells as well as the evaporative demand could increase, causing an increase of interception capacity of vegetation and consequently affecting ecological processes.

  11. LANDFILL OPERATION FOR CARBON SEQUESTRATION AND MAXIMUM METHANE EMISSION CONTROL

    SciTech Connect

    Don Augenstein

    1999-01-11

    ''Conventional'' waste landfills emit methane, a potent greenhouse gas, in quantities such that landfill methane is a major factor in global climate change. Controlled landfilling is a novel approach to manage landfills for rapid completion of total gas generation, maximizing gas capture and minimizing emissions of methane to the atmosphere. With controlled landfilling, methane generation is accelerated and brought to much earlier completion by improving conditions for biological processes (principally moisture levels) in the landfill. Gas recovery efficiency approaches 100% through use of surface membrane cover over porous gas recovery layers operated at slight vacuum. A field demonstration project's results at the Yolo County Central Landfill near Davis, California are, to date, highly encouraging. Two major controlled landfilling benefits would be the reduction of landfill methane emissions to minuscule levels, and the recovery of greater amounts of landfill methane energy in much shorter times than with conventional landfill practice. With the large amount of US landfill methane generated, and greenhouse potency of methane, better landfill methane control can play a substantial role in reduction of US greenhouse gas emissions.

  12. Effects of continuous cover forestry on soil moisture pattern - Beginning steps of a Hungarian study

    NASA Astrophysics Data System (ADS)

    Kalicz, Péter; Bartha, Dénes; Brolly, Gábor; Csáfordi, Péter; Csiszár, Ágnes; Eredics, Attila; Gribovszki, Zoltán; Király, Géza; Kollár, Tamás; Korda, Márton; Kucsara, Mihály; Nótári, Krisztina; Kornél Szegedi, Balázs; Tiborcz, Viktor; Zagyvai, Gergely; Zagyvai-Kiss, Katalin Anita

    2014-05-01

    Nowadays Hungarian foresters encounter a new challenge. The traditional management practices do not meet anymore with the demand of the civil society. The good old clearcut is no more a supported technology in forest regeneration. The transition to the continuous cover forestry induces much higher spatial variability compared to the even aged, more or less homogeneous, monoculture stands. The gap cutting is one of the proposed key methods in the Hungarian forestry. There is an active discussion among forest professionals how to determine the optimal gap size to maintain ideal conditions for the seedlings. Among other open questions for example how the surrounding trees modify the moisture pattern of the forest floor in the gap? In the early steps of a multidisciplinary project we established four research plots to study the spatial and temporal variability of soil moisture in the forest gap and the surrounding undisturbed stand. Each plot is located in oak (Quercus spp.) stands. Natural regeneration of oak stands is more problematic in our climate compared to the beech (Fagus sylvatica) which is located in the more humid or semi-humid areas of our country. All plots are located in the western part of Hungary: close to Sopron, Bejcgyertyános, Vép and Vajszló settlements. The last plot is an extensive research area, which is located in the riparian zone of a tributary of Feketevíz River. We monitor here the close-to-surface groundwater level fluctuation with pressure transducers. With a diurnal fluctuation based method it is possible to quantify the evapotranspiration differences between the gap and the stand. In two of the remaining stands (Bejcgyertyános and Vép) the gaps were opened in 2010. The monitoring of soil moisture began in 2013. A mobile sensor is used to monitor soil-moisture in a regular grid. The spatial variability of soil-moisture time-series shows a characteristic pattern during the growing-season. The plot in Sopron was established in 2013. Gaps with three different sizes were opened and fenced round to close out wild game. The initial status of the gap was recorded by a terrestrial laser scanner (LIDAR). From the resulting 3D point cloud high-resolution digital terrain and canopy surface model are derived which will help the planned numerical modelling. To prevent the unnecessary disturbance in this plot, two perpendicular transects were selected in each gap. The soil-moisture is monitored along these lines together with additional investigations, for example throughfall, and litter interception, tension disc infiltrometry, plant composition and cover. The microclimatic parameters such as near surface air temperature, relative humidity, radiation, wind speed and soil temperature is continuously recorded along the transects and compared to a nearby reference meteorological station located at an open area. Acknowledgment: The research was financially supported by the TÁMOP-4.2.2.A-11/1/KONV-2012-0004 joint EU-national research project

  13. Reclamation of a burned forest soil with municipal waste compost: macronutrient dynamic and improved vegetation cover recovery.

    PubMed

    Guerrero, C; Gmez, I; Moral, R; Mataix-Solera, J; Mataix-Beneyto, J; Hernndez, T

    2001-02-01

    The reclamation of burned soils in Mediterranean environments is of paramount importance in order to increase the levels of soil protection and minimise erosion and soil loss. The changes produced in the content of total organic carbon (TOC), N (Kjeldahl) and available P, K, Ca and Mg by the addition of different doses of a municipal solid waste compost to a burned soil were evaluated during one year. The effect of organic amendment on the improvement in the vegetation cover after one year was also evaluated. The organic amendment, particularly at a high dose, increased the TOC and N-Kjeldahl content of the soil in a closely related way. The levels of available K in soil were also enhanced by the organic amendment. Although the effects on all three parameters tended to decrease with time, their values in the amended soils were higher than in the control soil, which clearly indicates the improvement in the chemical quality of the soil brought about by the organic amendment. The available P content did not seem to be influenced by organic treatment, while available Mg levels were higher than in the control during the first 4 months following organic amendment. The application of compost to the burned soil improved its fertility and favoured rapid vegetal recovery, thus minimising the risk of soil erosion. PMID:11198173

  14. Strong dependence of CO2 emissions from anthropogenic land cover change on initial land cover and soil carbon parametrization

    NASA Astrophysics Data System (ADS)

    Goll, Daniel S.; Brovkin, Victor; Liski, Jari; Raddatz, Thomas; Thum, Tea; Todd-Brown, Kathe E. O.

    2015-09-01

    The quantification of sources and sinks of carbon from land use and land cover changes (LULCC) is uncertain. We investigated how the parametrization of LULCC and of organic matter decomposition, as well as initial land cover, affects the historical and future carbon fluxes in an Earth System Model (ESM). Using the land component of the Max Planck Institute ESM, we found that the historical (1750-2010) LULCC flux varied up to 25% depending on the fraction of biomass which enters the atmosphere directly due to burning or is used in short-lived products. The uncertainty in the decadal LULCC fluxes of the recent past due to the parametrization of decomposition and direct emissions was 0.6 Pg C yr-1, which is 3 times larger than the uncertainty previously attributed to model and method in general. Preindustrial natural land cover had a larger effect on decadal LULCC fluxes than the aforementioned parameter sensitivity (1.0 Pg C yr-1). Regional differences between reconstructed and dynamically computed land covers, in particular, at low latitudes, led to differences in historical LULCC emissions of 84-114 Pg C, globally. This effect is larger than the effects of forest regrowth, shifting cultivation, or climate feedbacks and comparable to the effect of differences among studies in the terminology of LULCC. In general, we find that the practice of calibrating the net land carbon balance to provide realistic boundary conditions for the climate component of an ESM hampers the applicability of the land component outside its primary field of application.

  15. Phytomass and soil organic carbon inventories related to land cover classification and periglacial features in Taimyr Peninsula,Siberia

    NASA Astrophysics Data System (ADS)

    Ramage, J. L.; Hugelius, G.; Kuhry, P.; Palmtag, J.; Lashchinskiy, N.

    2012-12-01

    The predicted increase in atmospheric temperatures is expected to affect the turnover of soil organic carbon in permafrost soils through modifications of the soil thermal regime. However, the tundra biome is formed of a mosaic of diverse landscape types with differing patterns of soil organic carbon storage and partitioning. Among these, differences in e.g. vegetation diversity and soil movements due to freeze-thaw processes are of main importance for assessing potential C remobilization under a changing climate. In this study, we described the storage of soil organic carbon (SOC) and the aboveground phytomass carbon in relation to geomorphology and periglacial features for two areas on Taymir Peninsula (Arctic Russia). An average of 29.5 kg C m2, calculated by upscaling with a land cover classification, is stored in the upper soil meter at these two study sites. The mean C phytomass storage amounts to ca.0.406 Kg C m2, or only 1.38 % of the total SOC storage. The topography, at different scales, plays an important role in the carbon partitioning. High amounts of soil organic carbon are found in highland areas and within the patterned ground features found in peatlands. The highest amounts of aboveground phytomass carbon are found in deciduous shrubs and moss layers. The large variability in carbon distribution within land cover types among the sites reveals the challenge of upscaling the carbon storage values over the Arctic and thus highlights the necessity to carry out detailed field inventories in this region.

  16. Effects of grazing on chemical soil properties and vegetation cover (case study: Kojour rangelands, Noushahr, Islamic Republic of Iran).

    PubMed

    Tamartash, R; Jalilvand, H; Tatian, M R

    2007-12-15

    This research is conducted to study the effects of grazing on chemical soil properties and vegetation cover in three areas separated as the key, reference and critical areas. The study area is located at the river basin of Kojour in the Southwestern of Noushahr (in the North of IR-Iran). Sampling and collecting the soil and vegetation cover data from the site areas are accomplished in the first step of the research. The vegetation cover data was collected in 20 sample plots of 1 m2 in each area. The data was collected through a random- systematic method in the early grazing season. The soil data was collected out of two layers (0-10, 10-30 cm), in two time intervals before and after grazing. Five samples were selected per layer. Some edaphical factors such as organic carbon, percentage of soil organic matters, total nitrogen, absorbable phosphorus and potassium, pH and EC were measured. The results revealed that there is an inverse relationship between the grazing intensity and amount of carbon, nitrogen, soil organic matter and EC. However, a direct relation exists between the grazing intensity and amount of soil potassium, phosphorus, pH and the ratio of carbon to nitrogen. Vegetation in class 1 and 2 which were cereals and forbs had greatest percentage in the reference area. Furthermore, the percentage forage cover increases with the grazing intensity. The more unpalatable vegetation of class 3 forms the prevailing coverage in the critical area. The conclusion of this study shows that overgrazing is considered as a threat for the nutritional elements of soil and vegetation cover. PMID:19093501

  17. The efficacy of winter cover crops to stabilize soil inorganic nitrogen after fall-applied anhydrous ammonia.

    PubMed

    Lacey, Corey; Armstrong, Shalamar

    2015-03-01

    There is a dearth of knowledge on the ability of cover crops to increase the effectiveness of fall-applied nitrogen (N). The objective of this study was to investigate the efficacy of two cover crop species to stabilize inorganic soil N after a fall application of N. Fall N was applied at a rate of 200 kg N ha into living stands of cereal rye, tillage radish, and a control (no cover crop) at the Illinois State University Research and Teaching Farm in Lexington, Illinois. Cover crops were sampled to determine N uptake, and soil samples were collected in the spring at four depths to 80 cm to determine the distribution of inorganic N within the soil profile. Tillage radish (131.9-226.8 kg ha) and cereal rye (188.1-249.9 kg ha N) demonstrated the capacity to absorb a minimum of 60 to 80% of the equivalent rate of fall-applied N, respectively. Fall applying N without cover crops resulted in a greater percentage of soil NO-N (40%) in the 50- to 80-cm depth, compared with only 31 and 27% when tillage radish and cereal rye were present at N application. At planting, tillage radish stabilized an average of 91% of the equivalent rate of fall-applied N within the 0- to 20-cm, depth compared with 66 and 57% for the cereal rye and control treatments, respectively. This study has demonstrated that fall applying N into a living cover crop stand has the potential to reduce the vulnerability of soil nitrate and to stabilize a greater concentration of inorganic N within the agronomic depths of soil. PMID:26023963

  18. AgRISTARS: Early warning and crop condition assessment. Plant cover, soil temperature, freeze, water stress, and evapotranspiration conditions

    NASA Technical Reports Server (NTRS)

    Wiegand, C. L. (Principal Investigator); Nixon, P. R.; Gausman, H. W.; Namken, L. N.; Leamer, R. W.; Richardson, A. J.

    1981-01-01

    Emissive (10.5 to 12.5 microns) and reflective (0.55 to 1.1 microns) data for ten day scenes and infrared data for six night scenes of southern Texas were analyzed for plant cover, soil temperature, freeze, water stress, and evapotranspiration. Heat capacity mapping mission radiometric temperatures were: within 2 C of dewpoint temperatures, significantly correlated with variables important in evapotranspiration, and related to freeze severity and planting depth soil temperatures.

  19. Strip-tilled cover cropping for managing nematodes, soil mesoarthropods, and weeds in a bitter melon agroecosystem.

    PubMed

    Marahatta, Sharadchandra P; Wang, Koon-Hui; Sipes, Brent S; Hooks, Cerruti R R

    2010-06-01

    A field trial was conducted to examine whether strip-tilled cover cropping followed by living mulch practice could suppress root-knot nematode (Meloidogyne incognita) and enhance beneficial nematodes and other soil mesofauna, while suppressing weeds throughout two vegetable cropping seasons. Sunn hemp (SH), Crotalaria juncea, and French marigold (MG), Tagetes patula, were grown for three months, strip-tilled, and bitter melon (Momordica charantia) seedlings were transplanted into the tilled strips; the experiment was conducted twice (Season I and II). Strip-tilled cover cropping with SH prolonged M. incognita suppression in Season I but not in Season II where suppression was counteracted with enhanced crop growth. Sunn hemp also consistently enhanced bacterivorous and fungivorous nematode population densities prior to cash crop planting, prolonged enhancement of the Enrichment Index towards the end of both cash crop cycles, and increased numbers of soil mesoarthropods. Strip-tilled cover cropping of SH followed by clipping of the living mulch as surface mulch also reduced broadleaf weed populations up to 3 to 4 weeks after cash crop planting. However, SH failed to reduce soil disturbance as indicated by the Structure Index. Marigold suppressed M. incognita efficiently when planted immediately following a M. incognita-susceptible crop, but did not enhance beneficial soil mesofauna including free-living nematodes and soil mesoarthropods. Strip-tilled cover cropping of MG reduced broadleaf weed populations prior to cash crop planting in Season II, but this weed suppression did not last beyond the initial cash crop cycle. PMID:22736847

  20. Strip-tilled Cover Cropping for Managing Nematodes, Soil Mesoarthropods, and Weeds in a Bitter Melon Agroecosystem

    PubMed Central

    Wang, Koon-Hui; Sipes, Brent S.; Hooks, Cerruti R.R.

    2010-01-01

    A field trial was conducted to examine whether strip-tilled cover cropping followed by living mulch practice could suppress root-knot nematode (Meloidogyne incognita) and enhance beneficial nematodes and other soil mesofauna, while suppressing weeds throughout two vegetable cropping seasons. Sunn hemp (SH), Crotalaria juncea, and French marigold (MG), Tagetes patula, were grown for three months, strip-tilled, and bitter melon (Momordica charantia) seedlings were transplanted into the tilled strips; the experiment was conducted twice (Season I and II). Strip-tilled cover cropping with SH prolonged M. incognita suppression in Season I but not in Season II where suppression was counteracted with enhanced crop growth. Sunn hemp also consistently enhanced bacterivorous and fungivorous nematode population densities prior to cash crop planting, prolonged enhancement of the Enrichment Index towards the end of both cash crop cycles, and increased numbers of soil mesoarthropods. Strip-tilled cover cropping of SH followed by clipping of the living mulch as surface mulch also reduced broadleaf weed populations up to 3 to 4 weeks after cash crop planting. However, SH failed to reduce soil disturbance as indicated by the Structure Index. Marigold suppressed M. incognita efficiently when planted immediately following a M. incognita-susceptible crop, but did not enhance beneficial soil mesofauna including free-living nematodes and soil mesoarthropods. Strip-tilled cover cropping of MG reduced broadleaf weed populations prior to cash crop planting in Season II, but this weed suppression did not last beyond the initial cash crop cycle. PMID:22736847

  1. Elimination of sulphur odours at landfills by bioconversion and the corona discharge plasma technique.

    PubMed

    Xia, Fangfang; Liu, Xin; Kang, Ying; He, Ruo; Wu, Zucheng

    2015-01-01

    Hydrogen sulphide (H2S) contributes a lot to odours at landfills, which is a threat to the environment and the health of the staff therein. To mitigate its emission, the bioconversion within landfill cover soils (LCSs) was introduced. H2S emission and concentration both in the field air above the landfill and in microcosm testing were surveyed. Results indicated that H2S emission and concentration in the landfill varied with landfill seasons and sites. There existed relationship between H2S concentration and fluxes spatially and temporally. To characterize and assess the spatial and temporal diversity of sulphur-oxidizing bacteria (SOB) and sulphate-reducing bacteria (SRB) in the LCSs, the terminal-restriction fragment length polymorphism technique was employed. Using the functional genes of dsrB and soxB, SOB, including Halothiobacillus, Rhodothalassium, Paracocccus, Allochromatium, and Thiobacillus, and SRB, including Desulfovibrio, Syntrophobacter, Desulfomonile and Desulfobacca, were identical and exhibited the dominant role in the LCSs. By employing an alternative available corona reactor, more than 90% removal efficiencies of sulphides were demonstrated, suggesting that the LCSs for eliminating odours in a lower concentration would be feasible. PMID:25244028

  2. Structure and condition of soil-vegetation cover in the Klyazma river basin applying remote sensing data

    NASA Astrophysics Data System (ADS)

    Mishchenko, Natalia; Trifonova, Tatiana; Repkin, Roman

    2015-04-01

    Constant observation of vegetation and soil cover is one of the key issues of river basins ecologic monitoring. It is necessary to consider that observation objects have been continuously changing and these changes are comprehensive and depend on temporal and dimensional parameters. Remote sensing data, embracing vast areas and reflecting various interrelations, allow excluding accidental and short-term changes though concentrating on the transformation of the observed river basin ecosystem environmental condition. The research objective is to assess spatial-temporal peculiarities of soil-vegetation structure formation in the Klyazma basin as a whole and minor river basins within the area. Research objects are located in the centre of European Russia. Data used in