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Sample records for affect soil properties

  1. Tillage system affects microbiological properties of soil

    NASA Astrophysics Data System (ADS)

    Delgado, A.; de Santiago, A.; Avilés, M.; Perea, F.

    2012-04-01

    Soil tillage significantly affects organic carbon accumulation, microbial biomass, and subsequently enzymatic activity in surface soil. Microbial activity in soil is a crucial parameter contributing to soil functioning, and thus a basic quality factor for soil. Since enzymes remain soil after excretion by living or disintegrating cells, shifts in their activities reflect long-term fluctuations in microbial biomass. In order to study the effects of no-till on biochemical and microbiological properties in comparison to conventional tillage in a representative soil from South Spain, an experiment was conducted since 1982 on the experimental farm of the Institute of Agriculture and Fisheries Research of Andalusia (IFAPA) in Carmona, SW Spain (37o24'07''N, 5o35'10''W). The soil at the experimental site was a very fine, montomorillonitic, thermic Chromic Haploxerert (Soil Survey Staff, 2010). A randomized complete block design involving three replications and the following two tillage treatments was performed: (i) Conventional tillage, which involved mouldboard plowing to a depth of 50 cm in the summer (once every three years), followed by field cultivation to a depth of 15 cm before sowing; crop residues being burnt, (ii) No tillage, which involved controlling weeds before sowing by spraying glyphosate and sowing directly into the crop residue from the previous year by using a planter with double-disk openers. For all tillage treatments, the crop rotation (annual crops) consisted of winter wheat, sunflower, and legumes (pea, chickpea, or faba bean, depending on the year), which were grown under rainfed conditions. Enzymatic activities (ß-glucosidase, dehydrogenase, aryl-sulphatase, acid phosphatase, and urease), soil microbial biomass by total viable cells number by acridine orange direct count, the density of cultivable groups of bacteria and fungi by dilution plating on semi-selective media, the physiological profiles of the microbial communities by BiologR, and the

  2. Switchgrass affects on soil property changes in the Great Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The capacity of perennial grasses to affect change in soil properties is well documented but soil property information on switchgrass (Panicum virgatum L.) managed for bioenergy is limited. Potential improvements in near-surface soil function are important should switchgrass be included as a perenn...

  3. Key soil functional properties affected by soil organic matter - evidence from published literature

    NASA Astrophysics Data System (ADS)

    Murphy, Brian

    2015-07-01

    The effect of varying the amount of soil organic matter on a range of individual soil properties was investigated using a literature search of published information largely from Australia, but also included relevant information from overseas. Based on published pedotransfer functions, soil organic matter was shown to increase plant available water by 2 to 3 mm per 10 cm for each 1% increase in soil organic carbon, with the largest increases being associated with sandy soils. Aggregate stability increased with increasing soil organic carbon, with aggregate stability decreasing rapidly when soil organic carbon fell below 1.2 to 1.5 5%. Soil compactibility, friability and soil erodibility were favourably improved by increasing the levels of soil organic carbon. Nutrient cycling was a major function of soil organic matter. Substantial amounts of N, P and S become available to plants when the soil organic matter is mineralised. Soil organic matter also provides a food source for the microorganisms involved in the nutrient cycling of N, P, S and K. In soils with lower clay contents, and less active clays such as kaolinites, soil organic matter can supply a significant amount of the cation exchange capacity and buffering capacity against acidification. Soil organic matter can have a cation exchange capacity of 172 to 297 cmol(+)/kg. As the cation exchange capacity of soil organic matter varies with pH, the effectiveness of soil organic matter to contribute to cation exchange capacity below pH 5.5 is often minimal. Overall soil organic matter has the potential to affect a range of functional soil properties.

  4. Spatial and temporal variability of soil hydraulic properties of topsoil affected by soil erosion

    NASA Astrophysics Data System (ADS)

    Nikodem, Antonin; Kodesova, Radka; Jaksik, Ondrej; Jirku, Veronika; Klement, Ales; Fer, Miroslav

    2014-05-01

    This study is focused on the comparison of soil hydraulic properties of topsoil that is affected by erosion processes. In order to include variable morphological and soil properties along the slope three sites - Brumovice, Vidim and Sedlčany were selected. Two transects (A, B) and five sampling sites along each one were chosen. Soil samples were taken in Brumovice after the tillage and sowing of winter wheat in October 2010 and after the wheat harvest in August 2011. At locality Vidim and Sedlčany samples were collected in May and August 2012. Soil hydraulic properties were studied in the laboratory on the undisturbed 100-cm3 soil samples placed in Tempe cells using the multi-step outflow test. Soil water retention data points were obtained by calculating water balance in the soil sample at each pressure head step of the experiment. The single-porosity model in HYDRUS-1D was applied to analyze the multi-step outflow and to obtain the parameters of soil hydraulic properties using the numerical inversion. The saturated hydraulic conductivities (Ks) and unsaturated hydraulic conductivities (Kw) for the pressure head of -2 cm of topsoil were also measured after the harvest using Guelph permeameter and Minidisk tensiometer, respectively. In general soil water retention curves measured before and after vegetation period apparently differed, which indicated soil material consolidation and soil-porous system rearrangement. Soil water retention curves obtained on the soil samples and hydraulic conductivities measured in the field reflected the position at the elevation transect and the effect of erosion/accumulation processes on soil structure and consequently on the soil hydraulic properties. The highest Ks values in Brumovice were obtained at the steepest parts of the elevation transects, that have been the most eroded. The Ks values at the bottom parts decreased due to the sedimentation of eroded soil particles. The change of the Kw values along transects didn't show

  5. Soil Properties Affecting the Reductive Capacity of Volcanic Ash Soils in Korea

    NASA Astrophysics Data System (ADS)

    Chon, C.; Ahn, J.; Kim, K.; Park, K.

    2008-12-01

    Volcanic ash soils or Andisols have distinct chemical and mineralogical properties. The unique chemical properties of Andisols are due to their Al-rich elemental composition, the highly reactive nature of their colloidal fractions, and their large surface area. The soils that developed from volcanic ash on Jeju Island, Korea, were classified as typical Andisols. The soils had an acidic pH, high water content, high organic matter, and clay-silty texture. The crystalline minerals in the samples were mainly ferromagnesian minerals, such as olivine and pyroxene, and iron oxides, such as magnetite and hematite derived from basaltic materials. A large amount of gibbsite was found in the subsurface horizon as a secondary product of the migration of excess Al. In addition, we found that considerable amounts of poorly ordered minerals like allophane and ferrihydrite were present in the Jeju soils. The SiO2 contents were lower than those of other soil orders, while the Al2O3 and Fe2O3 contents were higher. These results reflect some of the important chemical properties of Andisols. The chromium (VI/III) redox couple was used in the reductive capacity measurement. The mean reductive capacity of the Jeju soils was 6.53 mg/L reduced Cr(VI), which is 5.1 times higher than that of non-volcanic ash soils from inland Korea. The reductive capacity of the inland soils was correlated with the total carbon content. Such a high capacity for the reduction of soluble Cr(VI) must also be due to the relatively high carbon contents of the Jeju soils. Nevertheless, despite having 20 times higher total carbon contents, there was no correlation between the reductive capacity of the Jeju soils and the carbon content. These results imply that the reductive capacity of Jeju soils is not only controlled by the carbon content, but is also affected by other soil properties. Correlations of the reductive capacity with major elements showed that Al and Fe were closely connected to the reductive

  6. Soil hydraulic properties of topsoil along two elevation transects affected by soil erosion

    NASA Astrophysics Data System (ADS)

    Nikodem, Antonin; Kodesova, Radka; Jaksik, Ondrej; Jirku, Veronika; Fer, Miroslav; Klement, Ales; Zigova, Anna

    2013-04-01

    This study is focused on the comparison of soil hydraulic properties of topsoil that is affected by erosion processes. Studied area is characterized by a relatively flat upper part, a tributary valley in the middle and a colluvial fan at the bottom. Haplic Chernozem reminded at the flat upper part of the area. Regosols were formed at steep parts of the valley. Colluvial Chernozem and Colluvial soils were formed at the bottom parts of the valley and at the bottom part of the studied field. Two transects and five sampling sites along each one were selected. The soil-water retention curves measured on the undisturbed 100-cm3 soil samples taken after the tillage and sowing of winter wheat (October 2010) were highly variable and no differences between sampling sites within the each transect were detected. Variability of soil-water retention curves obtained on soil samples taken after the wheat harvest (August 2011) considerably deceased. The parts of the retention curves, which characterized the soil matrix, were very similar. The main differences between the soil-water retention curves were found in parts, which corresponded to larger capillary pores. The fractions of the large capillary pores (and also saturated soil water-contents) were larger after the harvest (soil structure reestablishment) than that after the tillage and sawing (soil structure disturbance). Greater amount of capillary pores was observed in soils with better developed soil structure documented on the micromorphological images. The saturated hydraulic conductivities (Ks) and unsaturated hydraulic conductivities (K) for the pressure head of -2 cm of topsoil were also measured after the wheat harvest using Guelph permeameter and Minidisk tensiometer, respectively. The highest Ks values were obtained at the steepest parts of the elevation transects, that have been the most eroded. The Ks values at the bottom parts decreased due to the sedimentation processes of eroded soil particles. The change of the

  7. Soil properties affecting wheat yields following drilling-fluid application.

    PubMed

    Bauder, T A; Barbarick, K A; Ippolito, J A; Shanahan, J F; Ayers, P D

    2005-01-01

    Oil and gas drilling operations use drilling fluids (mud) to lubricate the drill bit and stem, transport formation cuttings to the surface, and seal off porous geologic formations. Following completion of the well, waste drilling fluid is often applied to cropland. We studied potential changes in soil compaction as indicated by cone penetration resistance, pH, electrical conductivity (EC(e)), sodium adsorption ratio (SAR), extractable soil and total straw and grain trace metal and nutrient concentrations, and winter wheat (Triticum aestivum L. 'TAM 107') grain yield following water-based, bentonitic drilling-fluid application (0-94 Mg ha(-1)) to field test plots. Three methods of application (normal, splash-plate, and spreader-bar) were used to study compaction effects. We measured increasing SAR, EC(e), and pH with drilling-fluid rates, but not to levels detrimental to crop production. Field measurements revealed significantly higher compaction within areas affected by truck travel, but also not enough to affect crop yield. In three of four site years, neither drilling-fluid rate nor application method affected grain yield. Extractions representing plant availability and plant analyses results indicated that drilling fluid did not significantly increase most trace elements or nutrient concentrations. These results support land application of water-based bentonitic drilling fluids as an acceptable practice on well-drained soils using controlled rates. PMID:16091622

  8. Factors affecting soil cohesion

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil erodibility is a measure of a soil’s resistance against erosive forces and is affected by both intrinsic (or inherent) soil property and the extrinsic condition at the time erodibility measurement is made. Since soil erodibility is usually calculated from results obtained from erosion experimen...

  9. Do soil textural properties affect water use efficiency?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Soil-Plant-Environment Research (SPER) facility at USDA-ARS, Bushland, TX, was conceived by Terry A. Howell, Sr., and developed by the evapotranspiration (ET) research scientists at Bushland. It consists of a rain shelter and 48 weighing lysimeters containing monolithic soil cores of four soil ...

  10. Fractal Scaling of Particle Size Distribution and Relationships with Topsoil Properties Affected by Biological Soil Crusts

    PubMed Central

    Gao, Guang-Lei; Ding, Guo-Dong; Wu, Bin; Zhang, Yu-Qing; Qin, Shu-Gao; Zhao, Yuan-Yuan; Bao, Yan-Feng; Liu, Yun-Dong; Wan, Li; Deng, Ji-Feng

    2014-01-01

    Background Biological soil crusts are common components of desert ecosystem; they cover ground surface and interact with topsoil that contribute to desertification control and degraded land restoration in arid and semiarid regions. Methodology/Principal Findings To distinguish the changes in topsoil affected by biological soil crusts, we compared topsoil properties across three types of successional biological soil crusts (algae, lichens, and mosses crust), as well as the referenced sandland in the Mu Us Desert, Northern China. Relationships between fractal dimensions of soil particle size distribution and selected soil properties were discussed as well. The results indicated that biological soil crusts had significant positive effects on soil physical structure (P<0.05); and soil organic carbon and nutrients showed an upward trend across the successional stages of biological soil crusts. Fractal dimensions ranged from 2.1477 to 2.3032, and significantly linear correlated with selected soil properties (R2 = 0.494∼0.955, P<0.01). Conclusions/Significance Biological soil crusts cause an important increase in soil fertility, and are beneficial to sand fixation, although the process is rather slow. Fractal dimension proves to be a sensitive and useful index for quantifying changes in soil properties that additionally implies desertification. This study will be essential to provide a firm basis for future policy-making on optimal solutions regarding desertification control and assessment, as well as degraded ecosystem restoration in arid and semiarid regions. PMID:24516668

  11. Do stone bunds affect soil physical properties? - A case study in northern Ethiopia

    NASA Astrophysics Data System (ADS)

    Schürz, Christoph; Schwen, Andreas; Strohmeier, Stefan; Klik, Andreas

    2013-04-01

    Central issue of rain fed agriculture systems in the Ethiopian highlands is to store rain water in the soil during the rainy season (June to September). The aim is to maximize plant available water and to reduce surface runoff and soil erosion. Stone bunds are a common practice for soil and water conservation, influencing the translation processes of surface runoff. However, changes in surface hydrology affect the temporal and spatial properties of soil physical parameters. The objective of this research is to find a relationship between the spatial distribution of soil properties and the location of the stone bunds, but also to monitor the temporal behavior of those soil parameters, to better understand the impact of stone bunds on soil water movement. The research area is located in the Gumara Watershed, Maksegnit in Northern Ethiopia. There two representative transects were selected: One transect crosses three fields with conservation measures applied perpendicular to the stone bunds at a length of approximately 71 m. The second transect crosses a similar hill slope without conservation structures at a length of 55 m. During the rainy season in 2012 soil physical properties were monitored in specific spatial and temporal intervals. The measurements included bulk density, soil texture and volumetric water content. Tension infiltrometer tests were conducted to determine saturated and near saturated hydraulic conductivity for areas near stone bunds and the center of the fields on one hand, but also to derive van Genuchten parameters for those points inversely with Hydrus 2D. Slope steepness and stone cover along the transects were assessed, using survey and photogrammetric analysis. Preliminary results show an increase in the water content of topsoils within a range of approximately 2 m above the stone bunds but only random fluctuations in the field without conservation measures. At depths greater than 20 cm no significant differences in water content were found

  12. Linking hydraulic properties of fire-affected soils to infiltration and water repellency

    USGS Publications Warehouse

    Moody, J.A.; Kinner, D.A.; Ubeda, X.

    2009-01-01

    Heat from wildfires can produce a two-layer system composed of extremely dry soil covered by a layer of ash, which when subjected to rainfall, may produce extreme floods. To understand the soil physics controlling runoff for these initial conditions, we used a small, portable disk infiltrometer to measure two hydraulic properties: (1) near-saturated hydraulic conductivity, Kf and (2) sorptivity, S(??i), as a function of initial soil moisture content, ??i, ranging from extremely dry conditions (??i < 0.02 cm3 cm-3) to near saturation. In the field and in the laboratory replicate measurements were made of ash, reference soils, soils unaffected by fire, and fire-affected soils. Each has a different degrees of water repellency that influences Kf and S(??i). Values of Kf ranged from 4.5 ?? 10-3 to 53 ?? 10-3 cm s-1 for ash; from 0.93 ?? 10-3 to 130 ?? 10-3 cm s-1 for reference soils; and from 0.86 ?? 10-3 to 3.0 ?? 10-3 cm s-1, for soil unaffected by fire, which had the lowest values of Kf. Measurements indicated that S(??i) could be represented by an empirical non-linear function of ??i with a sorptivity maximum of 0.18-0.20 cm s-0.5, between 0.03 and 0.08 cm3 cm-3. This functional form differs from the monotonically decreasing non-linear functions often used to represent S(??i) for rainfall-runoff modeling. The sorptivity maximum may represent the combined effects of gravity, capillarity, and adsorption in a transitional domain corresponding to extremely dry soil, and moreover, it may explain the observed non-linear behavior, and the critical soil-moisture threshold of water repellent soils. Laboratory measurements of Kf and S(??i) are the first for ash and fire-affected soil, but additional measurements are needed of these hydraulic properties for in situ fire-affected soils. They provide insight into water repellency behavior and infiltration under extremely dry conditions. Most importantly, they indicate how existing rainfall-runoff models can be modified to

  13. Sodic Soil Properties and Sunflower Growth as Affected by Byproducts of Flue Gas Desulfurization

    PubMed Central

    Wang, Jinman; Bai, Zhongke; Yang, Peiling

    2012-01-01

    The main component of the byproducts of flue gas desulfurization (BFGD) is CaSO4, which can be used to improve sodic soils. The effects of BFGD on sodic soil properties and sunflower growth were studied in a pot experiment. The experiment consisted of eight treatments, at four BFGD rates (0, 7.5, 15 and 22.5 t ha−1) and two leaching levels (750 and 1200 m3 ha−1). The germination rate and yield of the sunflower increased, and the exchangeable sodium percentage (ESP), pH and total dissolved salts (TDS) in the soils decreased after the byproducts were applied. Excessive BFGD also affected sunflower germination and growth, and leaching improved reclamation efficiency. The physical and chemical properties of the reclaimed soils were best when the byproducts were applied at 7.5 t ha−1 and water was supplied at 1200 m3·ha−1. Under these conditions, the soil pH, ESP, and TDS decreased from 9.2, 63.5 and 0.65% to 7.8, 2.8 and 0.06%, and the germination rate and yield per sunflower reached 90% and 36.4 g, respectively. Salinity should be controlled by leaching when sodic soils are reclaimed with BFGD as sunflower growth is very sensitive to salinity during its seedling stage. PMID:23285042

  14. Sodic soil properties and sunflower growth as affected by byproducts of flue gas desulfurization.

    PubMed

    Wang, Jinman; Bai, Zhongke; Yang, Peiling

    2012-01-01

    The main component of the byproducts of flue gas desulfurization (BFGD) is CaSO(4), which can be used to improve sodic soils. The effects of BFGD on sodic soil properties and sunflower growth were studied in a pot experiment. The experiment consisted of eight treatments, at four BFGD rates (0, 7.5, 15 and 22.5 t ha(-1)) and two leaching levels (750 and 1200 m(3) ha(-1)). The germination rate and yield of the sunflower increased, and the exchangeable sodium percentage (ESP), pH and total dissolved salts (TDS) in the soils decreased after the byproducts were applied. Excessive BFGD also affected sunflower germination and growth, and leaching improved reclamation efficiency. The physical and chemical properties of the reclaimed soils were best when the byproducts were applied at 7.5 t ha(-1) and water was supplied at 1200 m(3)·ha(-1). Under these conditions, the soil pH, ESP, and TDS decreased from 9.2, 63.5 and 0.65% to 7.8, 2.8 and 0.06%, and the germination rate and yield per sunflower reached 90% and 36.4 g, respectively. Salinity should be controlled by leaching when sodic soils are reclaimed with BFGD as sunflower growth is very sensitive to salinity during its seedling stage. PMID:23285042

  15. Soil hydraulic properties affected by topsoil thickness in cultivated switchgrass and corn-soybean rotation production systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Loss of productive topsoil by soil erosion over time can reduce the productive capacity of soil and can significantly affect soil hydraulic properties. This study evaluated the effects of reduced topsoil thickness and perennial switchgrass (Panicum virgatum L.) versus corn (Zea mays L.)/soybean [Gly...

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

    NASA Astrophysics Data System (ADS)

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

    2014-05-01

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

  17. Microclimate affects soil chemical and mineralogical properties of cold-alpine soils of the Altai Mountains (Russia)

    NASA Astrophysics Data System (ADS)

    Egli, Markus; Lessovaia, Sofia; Chistyakov, Kirill; Inozemzev, Svyatoslav

    2013-04-01

    Precipitation and temperature particularly influence soil properties by affecting the type and rates of chemical, biological, and physical processes. To a great extent, element leaching and weathering rates are governed by these processes. Vegetation growth and decomposition, that depend on temperature and the other environmental factors, influence weathering reactions through the production of acidity and organic ligands that may promote chemical weathering and subsequent elemental leaching. The present work focuses on cold-alpine soils of the Altai Mountains (Siberia, Russia). The investigated field site (2380 m asl) is characterised by cold winters (with absolute minimum temperatures of -50°C; a mean temperature in January is -21°C) and cool summers (+8°C mean temperature in July). The mean annual temperature is -5.4°C. Annual precipitations are relatively low (500 mm with 20% of precipitation in July). Permafrost is widespread and occurs sometimes at a depth of 30 to 50 cm. Several studies have shown the influence of slope aspect and the resulting microclimate on soil weathering and development. There is however no unanimous agreement whether weathering is more intense on north- or south-facing slopes and whether small differences in thermal conditions may lead to detectable differences. Higher temperatures do not necessarily lead to higher weathering rates in cold alpine regions as shown by previous investigations in the European Alps. Water fluxes through the soils seemed to be more important. We consequently investigated soils in the cold-alpine environment of the Central Altai Mountains on a very small area close to a local glacier tongue. Half of the investigated soil profiles were south-facing (5) and the other half north-facing (5). The soils have the same parent material (mica-rich till), altitude, topography, and soil age. The vegetation is alpine grassland that is partially intersected with some juniper and mosses, which portion in the soil

  18. Biochar and soil properties affecting microbial transport through biochar-amended soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The incorporation of biochar into soils has been proposed as a means to sequester carbon from the atmosphere. An added environmental benefit is that biochar has also been shown to increase soil retention of nutrients, heavy metals, and pesticides. We have recently conducted a series of experiments t...

  19. Variability of soil properties and crop yield in landscapes affected by long-term tillage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Intensive tillage moves large quantities of soil, resulting in a pattern of soil redistribution where topsoil is depleted from convex slope positions and deposited in concave positions. In these experiments, the variation in erosion estimates, soil properties and crop yield were determined in a hill...

  20. Dryland soil chemical properties and crop yields affected by long-term tillage and cropping sequence

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Information on the effect of long-term management on soil nutrients and chemical properties is scanty. We examined the 30-yr effect of tillage frequency and cropping sequence combination on dryland soil Olsen-P, K, Ca, Mg, Na, SO4-S, and Zn concentrations, pH, electrical conductivity (EC), and catio...

  1. PREDOMINANT PROPERTIES AFFECTING PROFILE SOIL ELECTRICAL CONDUCTIVITY IN THE US MIDWEST

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Commercially available sensors for measuring apparent profile soil electrical conductivity (ECa) can provide an indirect indication of a number of soil physical and chemical properties helpful in characterizing within-field variability for precision agriculture. The objective of this research was to...

  2. Bacterial diversity and composition in major fresh produce growing soils affected by physiochemical properties and geographic locations.

    PubMed

    Ma, Jincai; Ibekwe, A Mark; Yang, Ching-Hong; Crowley, David E

    2016-09-01

    Microbial diversity of agricultural soils has been well documented, but information on leafy green producing soils is limited. In this study, we investigated microbial diversity and community structures in 32 (16 organic, 16 conventionally managed soils) from California (CA) and Arizona (AZ) using pyrosequencing, and identified factors affecting bacterial composition. Results of detrended correspondence analysis (DCA) and dissimilarity analysis showed that bacterial community structures of conventionally managed soils were similar to that of organically managed soils; while the bacterial community structures in soils from Salinas, California were different (P<0.05) from those in soils from Yuma, Arizona and Imperial Valley, California. Canonical correspondence analysis (CCA) and artificial neural network (ANN) analysis of bacterial community structures and soil variables showed that electrical conductivity (EC), clay content, water-holding capacity (WHC), pH, total nitrogen (TN), and organic carbon (OC) significantly (P<0.05) correlated with microbial communities. CCA based variation partitioning analysis (VPA) showed that soil physical properties (clay, EC, and WHC), soil chemical variables (pH, TN, and OC) and sampling location explained 16.3%, 12.5%, and 50.9%, respectively, of total variations in bacterial community structure, leaving 13% of the total variation unexplained. Our current study showed that bacterial community composition and diversity in major fresh produce growing soils from California and Arizona is a function of soil physiochemical characteristics and geographic distances of sampling sites. PMID:27135583

  3. Geohelminths distribution as affected by soil properties, physicochemical factors and climate in Sharkyia governorate Egypt.

    PubMed

    Etewa, Samia E; Abdel-Rahman, Sara A; Abd El-Aal, Naglaa F; Fathy, Ghada M; El-Shafey, Mahmoud A; Ewis, A M G

    2016-06-01

    Soil-transmitted helminths are mainly a group of parasitic nematodes causing human infection through contact with parasite eggs or larvae; they survive in the warm and moist soil of the tropical and subtropical countries. This study was carried out in Sharkyia governorate from October, 2011 to October, 2013, to correlate between the prevalence and distribution of these parasites in the soil and the physicochemical factors affecting the examined samples of the soil. One hundred and twenty samples of different types of soil (clay, silt, sand) from different localities were collected and examined. Diagnosis of geohelminths was confirmed by the recovery of their eggs and larvae with other protozoa by different parasitological methods. The modified baermann method was found to be more efficient in detection of geohelminths larvae than charcoal culture method. Among the examined sites geohelminths were much more numerous in the soil of rural areas especially in the spring and summer seasons, while the contamination of canal banks by geohelminths was the worst (80 %). An insignificant correlation was reported between the soil texture and the number of positive samples in the examined areas while the relationship was directly proportional among (moisture, PH, organic). It appeared that the most common geohelminthic stage was Toxocara spp. eggs besides other types of protozoa especially Balantidium coli cysts. This suggests that factors other than soil texture are important in the prevalence of geohelminths in the soil e.g. temperature, moisture, PH and organic matter. So, to change some of these factors in a trial to control geoparasites transmission but with keeping the environment should be tried. These results also open the way to further studies to highlight the mutual affection between inhabitants of these sites and the prevalence of these geoparasites. PMID:27413327

  4. Sheep Grazing in the Wheat-Fallow System Affects Dryland Soil Properties and Grain Yield

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sheep (Ovis aries L.) grazing during fallow is an effective method of controlling weeds and pests in the wheat (Triticum aestivum L.)-fallow system. Little is known about the effect of sheep grazing on dryland soil properties and wheat yield. We evaluated the effects of fallow management for weed co...

  5. Coarse fragments affects soil properties in a mantled-karst landscape of the Ozark Highlands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This paper investigates the effect of rock fragments on soil physical hydraulic properties within the mantled karst landscapes of the Savoy Experimental Watershed (SEW), a setting typical of much of the Ozark Plateaus. Water resources in these settings are highly susceptible to contamination. As a r...

  6. Nature's amazing biopolymer: basic mechanical and hydrological properties of soil affected by plant exudates

    NASA Astrophysics Data System (ADS)

    Naveed, Muhammad; Roose, Tiina; Raffan, Annette; George, Timothy; Bengough, Glyn; Brown, Lawrie; Keyes, Sam; Daly, Keith; Hallett, Paul

    2016-04-01

    Plant exudates are known to have a very large impact on soil physical properties through changes in mechanical and hydrological processes driven by long-chain polysaccharides and surface active compounds. Whilst these impacts are well known, the basic physical properties of these exudates have only been reported in a small number of studies. We present data for exudates obtained from barley roots and chia seeds, incorporating treatments examining biological decomposition of the exudates. When these exudates were added to a sandy loam soil, contact angle and drop penetration time increased exponentially with increasing exudate concentration. These wetting properties were strongly correlated with both exudate density and zero-shear viscosity, but not with exudate surface tension. Water holding capacity and water repellency of exudate mixed soil tremendously increased with exudate concentration, however they were significantly reduced on decomposition when measured after 14 days of incubation at 16C. Mechanical stability greatly increased with increasing exudate amendment to soils, which was assessed using a rheological amplitude sweep test near saturation, at -50 cm matric potential (field capacity) using indentation test, and at air-dry condition using the Brazilian test. This reflects that exudates not only attenuate plant water stress but also impart mechanical stability to the rhizosphere. These data are highly relevant to the understanding and modelling of rhizosphere development, which is the next phase of our research.

  7. Dryland soil chemical properties and crop yields affected by long-term tillage and cropping sequence.

    PubMed

    Sainju, Upendra M; Allen, Brett L; Caesar-TonThat, Thecan; Lenssen, Andrew W

    2015-01-01

    Information on the effect of long-term management on soil nutrients and chemical properties is scanty. We examined the 30-year effect of tillage frequency and cropping sequence combination on dryland soil Olsen-P, K, Ca, Mg, Na, SO4-S, and Zn concentrations, pH, electrical conductivity (EC), and cation exchange capacity (CEC) at the 0-120 cm depth and annualized crop yield in the northern Great Plains, USA. Treatments were no-till continuous spring wheat (Triticum aestivum L.) (NTCW), spring till continuous spring wheat (STCW), fall and spring till continuous spring wheat (FSTCW), fall and spring till spring wheat-barley (Hordeum vulgare L., 1984-1999) followed by spring wheat-pea (Pisum sativum L., 2000-2013) (FSTW-B/P), and spring till spring wheat-fallow (STW-F, traditional system). At 0-7.5 cm, P, K, Zn, Na, and CEC were 23-60% were greater, but pH, buffer pH, and Ca were 6-31% lower in NTCW, STCW, and FSTW-B/P than STW-F. At 7.5-15 cm, K was 23-52% greater, but pH, buffer pH, and Mg were 3-21% lower in NTCW, STCW, FSTCW, FSTW-B/P than STW-F. At 60-120 cm, soil chemical properties varied with treatments. Annualized crop yield was 23-30% lower in STW-F than the other treatments. Continuous N fertilization probably reduced soil pH, Ca, and Mg, but greater crop residue returned to the soil increased P, K, Na, Zn, and CEC in NTCW and STCW compared to STW-F. Reduced tillage with continuous cropping may be adopted for maintaining long-term soil fertility and crop yields compared with the traditional system. PMID:26171303

  8. The sorption characteristics of mercury as affected by organic matter content and/or soil properties

    NASA Astrophysics Data System (ADS)

    Šípková, Adéla; Šillerová, Hana; Száková, Jiřina

    2014-05-01

    The determination and description of the mercury sorption extend on soil is significant for potential environmental toxic effects. The aim of this study was to assess the effectiveness of mercury sorption at different soil samples and vermicomposts. Mercury interactions with soil organic matter were studied using three soils with different physical-chemical properties - fluvisol, cambisol, and chernozem. Moreover, three different vermicomposts based on various bio-waste materials with high organic matter content were prepared in special fermentors. First was a digestate, second was represented by a mixture of bio-waste from housing estate and woodchips, and third was a garden bio-waste. In the case of vermicompost, the fractionation of organic matter was executed primarily using the resin SuperliteTM DAX-8. Therefore, the representation of individual fractions (humic acid, fulvic acid, hydrophilic compounds, and hydrophobic neutral organic matter) was known. The kinetics of mercury sorption onto materials of interest was studied by static sorption experiments. Samples were exposed to the solution with known Hg concentration of 12 mg kg-1 for the time from 10 minutes to 24 hours. Mercury content in the solutions was measured by the inductively coupled plasma mass spectrometry (ICP-MS). Based on this data, the optimum conditions for following sorption experiments were chosen. Subsequently, the batch sorption tests for all soil types and vermicomposts were performed in solution containing variable mercury concentrations between 1 and 12 mg kg-1. Equilibrium concentration values measured in the solution after sorption and calculated mercury content per kilogram of the soil or the vermi-compost were plotted. Two basic models of sorption isotherm - Langmuir and Freundlich, were used for the evaluation of the mercury sorption properties. The results showed that the best sorption properties from studied soil were identified in chernozem with highest cation exchange

  9. Salvage logging effect on soil properties in a fire-affected Mediterranean forest: a two years monitoring research

    NASA Astrophysics Data System (ADS)

    Mataix-Solera, Jorge; Moltó, Jorge; Arcenegui, Vicky; García-Orenes, Fuensanta; Chrenkovà, Katerina; Torres, Pilar; Jara-Navarro, Ana B.; Díaz, Gisela; Izquierdo, Ezequiel

    2015-04-01

    In the Mediterranean countries, forest fires are common and must be considered as an ecological factor, but changes in land use, especially in the last five decades have provoked a modification in their natural regime. Moreover, post-fire management can have an additional impact on the ecosystem; in some cases, even more severe than the fire. Salvage logging is a traditional management in most fire-affected areas. In some cases, the way of doing it, using heavy machinery, and the vulnerability of soils to erosion and degradation make this management potentially very agresive to soil, and therefore to the ecosystem. Very little research has been done to study how this treatment could affect soil health. In this research we show 2 years of monitoring of some soil properties in an area affected by a forest fire, where some months later this treatment was applied. The study area is located in 'Sierra de Mariola Natural Park' in Alcoi, Alicante (E Spain). A big forest fire (>500 has) occurred in July 2012. The forest is composed mainly of Pinus halepensis trees with an understory of typical Mediterranean shrubs species such as Quercus coccifera, Rosmarinus officinalis, Thymus vulgaris, Brachypodium retusum, etc. Soil is classified as a Typic Xerorthent (Soil Survey Staff, 2014) developed over marls. In February 2013, salvage logging (SL) treatment consisting in a complete extraction of the burned wood using heavy machinery was applied in a part of the affected forest. Plots for monitoring this effect were installed in this area and in a similar nearby area where no treatment was done, and then used as control (C) for comparison. Soil samplings were done immediately after treatment and every 6 months. Some soil properties were analysed, including soil organic matter (SOM) content, basal soil respiration (BSR), microbial biomass carbon (MBC), bulk density (BD), soil water repellency (SWR), aggregate stability (AS), field capacity, nitrogen, etc. After two years of

  10. Stable isotopes of soil water are affected by clay minerals: A post correction approach for dry soils based on physicochemical soil properties

    NASA Astrophysics Data System (ADS)

    Gaj, Marcel; Kaufhold, Stephan; Koeniger, Paul; Matthias, Beyer; Himmelsbach, Thomas

    2016-04-01

    The cryogenic vacuum extraction is commonly used to access soil water that will be subsequently analyzed for stable isotopes (18O and 2H). However, the analytical error associated with this method is high compared to that of stable isotopes measured directly from water samples. Additionally, the accuracy of data derived from soil water extractions decreases with the increasing presence of fine compounds such as silt and clay. To overcome these limitations an extended applicability of the cryogenic vacuum extraction method is demonstrated. This study proposes two new methods to improve isotope values using the cryogenic vacuum extraction method. First, by showing that the extraction temperature of 205 ° C improves the precision and the accuracy for all tested soil types. Secondly, that the post correction of data based on physicochemical soil properties and common extraction temperature will reduce errors. Results show a reduction in error of d-values of soil water derived from soils with clay content between 0.1 to 48 %. The analytical error could be significantly reduced compared to previous studies by increasing the extraction temperature even for soils with high clay content. Soil water extractions from sandy soils are improved by halving the analytical error. If soil material is available, the proposed correction scheme can be applied to past isotope data and will improve comparability between studies and heterogeneous soils. It is recommended to conduct spike experiments prior to unsaturated zone isotope studies. We encourage future experiments with extraction temperatures above 205 ° C. If previously oven dried substrate is used for standard preparation old water might remain in soil with a fine texture (i.e., high clay content) after oven drying at 105 ° C and that this old water will enrich any added calibration water resulting in the enrichment of all samples normalized using it.

  11. Vermicompost affects soil properties and spinach growth, physiology, and nutritional value

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of vermicompost to improve soil fertility and enhance crop yield has gained considerable momentum due to its contribution to agroecological sustainability. Short-term (35-days after transplanting) effects of vermicompost, applied either as a soil amendment (5% and 10%, v/v), or a drench (40 ...

  12. Soil and Sediment Properties Affecting the Transport and Accumulations of Mercury in a Flood Control Reservoir

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Mercury accumulations in some fish species from Grenada Lake in north Mississippi exceed the Food and Drug Administration standards for human consumption. This large flood control reservoir serves as a sink for the Skuna and Yalobusha River watersheds whose highly erodible soils contribute to exces...

  13. VINEYARD FLOOR MANAGEMENT STRATEGIES AFFECT SOIL PROPERTIES & MICROBIOLOGY, WATER RELATIONS, AND CROP NUTRITION

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A long-term comparison of various vineyard floor management practices (weed control and cover crops) indicates that weed control treatments had no impact on soil microbial biomass, but had a significant interactive effect with the rye cover crop on mycorrhizal colonization of grapevine roots, presum...

  14. Soil Properties and Productivity as Affected by Topsoil Movement within an Eroded Landform

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In hilly landforms subject to long-term cultivation, erosion has denuded upper slope positions of topsoil and accumulated topsoil in lower slope positions. One approach to remediate these eroded landforms is moving soil from areas of topsoil accumulation to areas of topsoil depletion, termed here so...

  15. Electrical properties of soils

    NASA Astrophysics Data System (ADS)

    Pozdnyakova, Larisa A.

    In this study, thorough analysis is conducted for soil electrical properties, i.e. electrical resistivity, conductivity, and potential. Soil electrical properties are the parameters of natural and artificially created electrical fields in soils and influenced by distribution of mobile electrical charges, mostly inorganic ions, In soils. Distributions of electrical charges and properties in various soil profiles were shown to be results of the soil-forming processes. Soil properties influencing the density of mobile electrical charges were found to be exponentially related with electrical resistivity and potential based on Boltzmann's law of statistical thermodynamics. Relationships were developed between electrical properties and other soil physical and chemical properties, such as texture, stone content, bulk density, water content, cation exchange capacity, salinity, humus content, and base saturation measured in-situ and in soil samples. Geophysical methods of vertical electrical sounding, four-electrode probe, non-contact electromagnetic profiling, and self-potential were modified for measuring soil electrical properties and tested in different soil studies. The proposed methods are extremely efficient, reliable, and non-disturbing. Compared with conventional methods of soil analysis, the electrical geophysical methods allowed evaluating groundwater table, salt content, depth and thickness of soil horizons, Polluted or disturbed layers in soil profiles, and stone content with an estimation error <10%. The methods provide extensive data on spatial and temporal variations in soil electrical properties, which relate to the distributions of other essential soil properties. The electrical properties were incorporated with the data from conventional soil analyses to enhance the estimation of a number of soil physical and chemical properties and to assist soil survey. The study shows various applications of the modified geophysical methods in soil physics, soil

  16. How the insulating properties of snow affect soil carbon distribution in the continental pan-Arctic area

    NASA Astrophysics Data System (ADS)

    Gouttevin, I.; Menegoz, M.; Dominé, F.; Krinner, G.; Koven, C.; Ciais, P.; Tarnocai, C.; Boike, J.

    2012-06-01

    We demonstrate the effect of an ecosystem differentiated insulation by snow on the soil thermal regime and on the terrestrial soil carbon distribution in the pan-Arctic area. This is done by means of a sensitivity study performed with the land surface model ORCHIDEE, which furthermore provides a first quantification of this effect. Based on field campaigns reporting higher thermal conductivities and densities for the tundra snowpack than for taiga snow, two distributions of near-equilibrium soil carbon stocks are computed, one relying on uniform snow thermal properties and the other using ecosystem-differentiated snow thermal properties. Those modeled distributions strongly depend on soil temperature through decomposition processes. Considering higher insulation by snow in taiga areas induces warmer soil temperatures by up to 12 K in winter at 50 cm depth. This warmer soil signal persists over summer with a temperature difference of up to 4 K at 50 cm depth, especially in areas exhibiting a thick, enduring snow cover. These thermal changes have implications on the modeled soil carbon stocks, which are reduced by 8% in the pan-Arctic continental area when the vegetation-induced variations of snow thermal properties are accounted for. This is the result of diverse and spatially heterogeneous ecosystem processes: where higher soil temperatures lift nitrogen limitation on plant productivity, tree plant functional types thrive whereas light limitation and enhanced water stress are the new constrains on lower vegetation, resulting in a reduced net productivity at the pan-Arctic scale. Concomitantly, higher soil temperatures yield increased respiration rates (+22% over the study area) and result in reduced permafrost extent and deeper active layers which expose greater volumes of soil to microbial decomposition. The three effects combine to produce lower soil carbon stocks in the pan-Arctic terrestrial area. Our study highlights the role of snow in combination with

  17. Soil properties controlling infiltration in volcanic soils

    NASA Astrophysics Data System (ADS)

    Neris, Jonay; Tejedor, Marisa; Jiménez, Concepción

    2013-04-01

    Soil water infiltration is an important process whose behaviour depends on external factors and soil properties that vary depending on the type of soil. The soil parameters affecting the infiltration capacity of six soil orders all formed on volcanic materials (andisols, vertisols, alfisols, aridisols, inceptisols, and entisols) and contribute to the differences between them were studied in this paper. A total of 108 sites were selected on the island of Tenerife (Spain). The main soil properties were analysed and the steady-state infiltration rate measured using a double-ring infiltrometer. The relationship between the soil properties and infiltration was modelled using statistical Principal Components Analysis and regressions. The research concludes that the relation between structural development and texture play a decisive role. The high structural development of non-vitric andisols, due to the high organic matter and short-range-order mineral content, leads to an extremely fast infiltration rate. The structural instability and fine texture of aridisols produce low infiltration. In less developed soils (entisols and vitric andisols) where aggregate formation is minimal or non-existent, the coarse grain size is the relevant factor determining their very fast and extremely fast infiltration. In vertisols and alfisols, which have strong aggregation but low stability, clay type and content play an important role and lead to a moderate and moderately fast steady-state infiltration rate, respectively. In the most typic inceptisols, with moderate structural development and stability, the balance of the properties is largely responsible for the intermediate infiltration rate observed.

  18. Tree species affect cation exchange capacity (CEC) and cation binding properties of organic matter in acid forest soils.

    PubMed

    Gruba, Piotr; Mulder, Jan

    2015-04-01

    Soil organic matter (SOM) in forest soil is of major importance for cation binding and acid buffering, but its characteristics may differ among soils under different tree species. We investigated acidity, cation exchange properties and Al bonding to SOM in stands of Scots pine, pedunculate oak, Norway spruce, European beech and common hornbeam in southern Poland. The content of total carbon (Ct) was by far the major contributor to total cation exchange capacity (CECt) even in loamy soils and a strong relationship between Ct and CECt was found. The slope of the regression of CECt to Ct increased in the order hornbeam≈oaksoils. This was supported by the apparent dissociation constant (pKapp) values of SOM, which were largest in soils under oak. The maximum values of Al saturation were similar between the stands. However, maximum Al bonding to SOM occurred at higher pH values in soils under pine and spruce than under oak. Therefore, at any value in the acid pH range, the SOM in pine soil has less Al complexed and more adsorbed H+ than SOM from oak soils. Such differences in Al and H bonding are not only important for pH buffering and metal solubility controls, but also for stabilization of SOM via saturation of functional groups by Al and H. PMID:25596350

  19. Can soil drying affect the sorption of pesticides in soil?

    NASA Astrophysics Data System (ADS)

    Chaplain, Véronique; Saint, Philippe; Mamy, Laure; Barriuso, Enrique

    2010-05-01

    The sorption of pesticides in soils mainly controls their further dispersion into the environment. Sorption is usually related to the physico-chemical properties of molecules but it also depends on the hydrophobic features of soils. However, the hydrophobicity of soils changes with wetting and drying cycles and this can be enhanced with climate change. The objective of this study was to measure by using controlled artificial soils the influence of the hydrophobic characteristic of soils on the retention of a model pesticide. Artificial soils consisted in silica particles covered by synthetic cationic polymers. Polymers were characterized by the molar ratio of monomers bearing an alkyl chain of 12C. Two polymers were used, with 20 and 80 % ratios, and the same degree of polymerization. In addition, porous and non-porous particles were used to study the accessibility notion and to measure the influence of diffusion on pesticide sorption kinetics. Lindane was chosen as model molecule because its adsorption is supposed mainly due to hydrophobic interactions. Results on polymers adsorption on silica showed that it was governed by electrostatic interactions, without any dependency of the hydrophobic ratio. Polymers covered the entire surface of porous particles. Kinetic measurements showed that lindane sorption was slowed in porous particles due to the molecular diffusion inside the microporosity. The adsorption of lindane on covered silica particles corresponded to a partition mechanism described by linear isotherms. The slope was determined by the hydrophobic ratio of polymers: the sorption of lindane was highest in the most hydrophobic artificial soil. As a result, modification in soil hydrophobicity, that can happen with climate change, might affect the sorption and the fate of pesticides. However additional experiments are needed to confirm these first results. Such artificial soils should be used as reference materials to compare the reactivity of pesticides, to

  20. Short-time effect of salvage harvesting on microbial soil properties in a Mediterranean area affected by a wildfire: preliminary results

    NASA Astrophysics Data System (ADS)

    Moltó, Jorge; Mataix-Solera, Jorge; Arcenegui, Victoria; Morugan, Alicia; Girona, Antonio; Garcia-orenes, Fuensanta

    2014-05-01

    In the Mediterranean region, wildfires are considered one of the main ecological factors, which, in addition to and in relation to changes in soil use, may cause soil loss and degradation, one of the most important environmental problems that humanity must face up to. As is well known, the soil-plant system is one of the key factors determining ecological recovery after the occurrence of a wildfire. Traditionally, a variety of forestry practices have been implemented on spanish sites after the incidence of a wildfire. Among them stands out the complete extraction of the burned wood, which consist in getting rid of the branches and other wooden debris using small controlled bonfires, splintering or mechanical extraction. This set of post-fire management practices is known as salvage logging or salvage harvesting. Despite the remarkable relevance and influence that this conjunction of techniques has on land management after a wildfire, very little experimental research focused on assessing the impact of salvage logging on the vegetal community has been done. Furthermore, even less research inquiring into the mode and grade of incidence that the salvage logging produces on soil properties has taken place. The aim of this research is to assess the effects that the salvage harvesting has on different soil microbial properties and other related properties. The study area is located in the Natural Park of the "Sierra de Mariola" in the province of Alicante, southeastern Spain. This location was affected by a wildfire whose extension reached more than 500 Ha in July 2012. Different post-fire treatments were proposed by the authorities, including salvage harvesting in some areas. Two different treatments were distinguished for the study, "control" (without any kind of burned wood removal) and "harvest" (where salvage logging was carried out), in each area three 4 m2 sampling plots were set up. These two treatments were established on the same slope with the same orography

  1. Soil fauna, soil properties and geo-ecosystem functioning

    NASA Astrophysics Data System (ADS)

    Cammeraat, L. H.

    2012-04-01

    The impact of soil fauna on soil processes is of utmost importance, as the activity of soil fauna directly affects soil quality. This is expressed by the direct effects of soil fauna on soil physical and soil chemical properties that not only have great importance to food production and ecosystems services, but also on weathering and hydrological and geomorphological processes. Soil animals can be perceived as ecosystem engineers that directly affect the flow of water, sediments and nutrients through terrestrial ecosystems. The biodiversity of animals living in the soil is huge and shows a huge range in size, functions and effects. Most work has been focused on only a few species such as earthworms and termites, but in general the knowledge on the effect of soil biota on soil ecosystem functioning is limited as it is for their impact on processes in the soil and on the soil surface. In this presentation we would like to review some of the impacts of soil fauna on soil properties that have implications for geo-ecosystem functioning and soil formation processes.

  2. Rock Content Influence on Soil Hydraulic Properties

    NASA Astrophysics Data System (ADS)

    Parajuli, K.; Sadeghi, M.; Jones, S. B.

    2015-12-01

    Soil hydraulic properties including the soil water retention curve (SWRC) and hydraulic conductivity function are important characteristics of soil affecting a variety of soil properties and processes. The hydraulic properties are commonly measured for seived soils (i.e. particles < 2 mm), but many natural soils include rock fragments of varying size that alter bulk hydraulic properties. Relatively few studies have addressed this important problem using physically-based concepts. Motivated by this knowledge gap, we set out to describe soil hydraulic properties using binary mixtures (i.e. rock fragment inclusions in a soil matrix) based on individual properties of the rock and soil. As a first step of this study, special attention was devoted to the SWRC, where the impact of rock content on the SWRC was quantified using laboratory experiments for six different mixing ratios of soil matrix and rock. The SWRC for each mixture was obtained from water mass and water potential measurements. The resulting data for the studied mixtures yielded a family of SWRC indicating how the SWRC of the mixture is related to that of the individual media, i.e., soil and rock. A consistent model was also developed to describe the hydraulic properties of the mixture as a function of the individual properties of the rock and soil matrix. Key words: Soil hydraulic properties, rock content, binary mixture, experimental data.

  3. Atlas of soil reflectance properties

    NASA Technical Reports Server (NTRS)

    Stoner, E. R.; Baumgardner, M. F.; Biehl, L. L.; Robinson, B. F.

    1979-01-01

    A compendium of soil spectral reflectance curves together with soil test results and site information is presented in an abbreviated manner listing those soil properties most important in influencing soil reflectance. Results are presented for 251 soils from 39 states and Brazil. A narrative key describes relationships between soil parameters and reflectance curves. All soils are classified according to the U.S. soil taxonomy and soil series name for ease of identification.

  4. Composting of biochars improves their sorption properties, retains nutrients during composting and affects greenhouse gas emissions after soil application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Biochar application to soils has been suggested to elevate nutrient sorption, improve soil fertility and reduce net greenhouse gas (GHG) emissions. We examined the impact of composting biochar together with a biologically active substrate (i.e., livestock manure-straw mixture). We hypothesized that ...

  5. Soil properties affect the toxicities of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to the enchytraeid worm Enchytraeus crypticus.

    PubMed

    Kuperman, Roman G; Checkai, Ronald T; Simini, Michael; Phillips, Carlton T; Kolakowski, Jan E; Lanno, Roman

    2013-11-01

    The authors investigated individual toxicities of 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) to the potworm Enchytraeus crypticus using the enchytraeid reproduction test. Studies were designed to generate ecotoxicological benchmarks that can be used for developing ecological soil-screening levels for ecological risk assessments of contaminated soils and to identify and characterize the predominant soil physicochemical parameters that can affect the toxicities of TNT and RDX to E. crypticus. Soils, which had a wide range of physicochemical parameters, included Teller sandy loam, Sassafras sandy loam, Richfield clay loam, Kirkland clay loam, and Webster clay loam. Analyses of quantitative relationships between the toxicological benchmarks for TNT and soil property measurements identified soil organic matter content as the dominant property mitigating TNT toxicity for juvenile production by E. crypticus in freshly amended soil. Both the clay and organic matter contents of the soil modulated reproduction toxicity of TNT that was weathered and aged in soil for 3 mo. Toxicity of RDX for E. crypticus was greater in the coarse-textured sandy loam soils compared with the fine-textured clay loam soils. The present studies revealed alterations in toxicity to E. crypticus after weathering and aging TNT in soil, and these alterations were soil- and endpoint-specific. PMID:23955807

  6. Microbial effect on soil hydraulic properties

    NASA Astrophysics Data System (ADS)

    Furman, Alex; Rosenzweig, Ravid; Volk, Elazar; Rosenkranz, Hella; Iden, Sascha; Durner, Wolfgang

    2014-05-01

    Although largely ignored, the soil contains large amount of biofilms (attached microbes) that can affect many processes. While biochemical processes are studied, biophysical processes receive only little attention. Biofilms may occupy some of the pore space, and by that affect the soil hydraulic properties. This effect on unsaturated soils, however, was not intensively studied. In this research we directly measure the hydraulic properties, namely the soil's unsaturated hydraulic conductivity function and retention curve, for soils containing real biofilm. To do that we inoculate soil with biofilm-forming bacteria and incubate it with sufficient amounts of nutrient until biofilm is formed. The hydraulic properties of the incubated soil are then measured using several techniques, including multi-step outflow and evaporation method. The longer measurements (evaporation method) are conducted under refrigeration conditions to minimize microbial activity during the experiment. The results show a clear effect of the biofilm, where the biofilm-affected soil (sandy loam in our case) behaves like a much finer soil. This qualitatively makes sense as the biofilm generates an effective pore size distribution that is characterized by smaller pores. However, the effect is much more complex and needs to be studied carefully considering (for example) dual porosity models. We compare our preliminary results with other experiments, including flow-through column experiments and experiments with biofilm analogues. Clearly a better understanding of the way microbial activity alters the hydraulic properties may help designing more efficient bioremediation, irrigation, and other soil-related processes.

  7. Soil Aggregation and Carbon Sequestration as affected by Long-Term Tillage Practices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In agricultural systems, soil structure is an important property that mediates many soil physical and biological processes and controls soil organic carbon (SOC) content. Cultivation affects soil structure due to the destruction of soil aggregates and the lost of SOC. Different management practices...

  8. Soil moisture regime and soil type affect the decomposition of graminoid litter grown under three levels of atmospheric CO2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Increases in atmospheric CO2 can augment the quantity and change the quality of plant carbon (C) inputs into grassland soils. Soil moisture interacts with substrate characteristics and soil properties to affect decomposition and transfer of plant-derived C into soil organic matter (SOM). Thus, pre...

  9. Normal water irrigation as an alternative to effluent irrigation in improving rice grain yield and properties of a paper mill effluent affected soil.

    PubMed

    Boruah, D; Hazarika, S

    2010-07-01

    Rice crop (var. Luit) was grown under controlled conditions in paper mill effluent contaminated soil and irrigated with undiluted paper mill effluent as well as normal water and compared the results against a control treatment consisting of similar unaffected soil irrigated with normal water. The effluent was alkaline (pH 7.5), containing high soluble salts (EC 2.93 dS m(-1)), chloride (600 mg L(-1)) and total dissolved solids (1875 mg L(-1)). At maximum tillering (MT) stage effluent irrigation significantly (P < 0.05) reduced the leaf numbers per hill and leaf area by 19.8 and 36.4 %, respectively. Tiller number and maximum root length were reduced by 19.3% and 12.5%, respectively at fifty percent flowering (FF) stage. Effluent irrigated crop recorded significant reduction in the dry matter production (17.5-24.9%) and grain yield (19%). Unfilled grain was increased by 10.7%. Higher concentration of sodium, calcium and magnesium in the effluent irrigated soil affected K uptake. Available soil P was lowest while available N, K, S and exchangeable and water soluble Na, K, Ca, Mg were highest in effluent irrigated soil. Chloride content found to increase (3-7 folds) while microbial biomass carbon reduced (10-37%). The adverse effect of the paper mill effluent on the crop as well as on the affected soil could be reduced significantly through normal water irrigation. PMID:21391395

  10. Factors affecting the degradation of pharmaceuticals in agricultural soils.

    PubMed

    Monteiro, Sara C; Boxall, Alistair B A

    2009-12-01

    Pharmaceuticals may be released to the soil environment through the application of biosolids to land. To understand those factors affecting the persistence of pharmaceuticals in the soil environment, the present study was performed to assess the effects of soil type, the presence of biosolids, and the impact of chemical mixture interactions on the degradation of three pharmaceuticals: naproxen, carbamazepine, and fluoxetine. Single-compound studies showed that naproxen degraded in a range of soils with half-lives ranging from 3.1 to 6.9 d and in biosolids with a half-life of 10.2 d. No relationships were observed between degradation rate and soil physicochemical properties and soil bioactivity. For naproxen, addition of biosolids to soils reduced the degradation rate observed in the soil-only studies, with half-lives in the soil-biosolid systems ranging from 3.9 to 15.1 d. Carbamazepine and fluoxetine were found to be persistent in soils, biosolids, and soil-biosolid mixtures. When degradation was assessed using a mixture of the three study compounds and the sulfonamide antibiotic sulfamethazine, the degradation behavior of fluoxetine and carbamazepine was similar to that observed in the single compound studies (i.e., no degradation). However, the degradation rate of naproxen in soils, biosolids, and soil-biosolid systems spiked with the mixture was significantly slower than in the single-compound studies. As degradation studies for risk assessment purposes are performed using single substances in soil-only studies, it is possible that current risk assessment procedures will underestimate environmental impacts. Further work is therefore warranted on a larger range of substances, soils, biosolid types, and chemical mixtures to better understand the fate of pharmaceuticals in terrestrial systems. PMID:19580336

  11. Hydraulic Properties of Unsaturated Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many agrophysical applications require knowledge of the hydraulic properties of unsaturated soils. These properties reflect the ability of a soil to retain or transmit water and its dissolved constituents. The objective of this work was to develop an entry for the Encyclopedia of Agrophysics that w...

  12. Soil cultivation in vineyards alters interactions between soil biota and soil physical and hydrological properties

    NASA Astrophysics Data System (ADS)

    Zaller, Johann G.; Buchholz, Jacob; Querner, Pascal; Winter, Silvia; Kratschmer, Sophie; Pachinger, Bärbel; Strauss, Peter; Bauer, Thomas; Stiper, Katrin; Potthoff, Martin; Guernion, Muriel; Scimia, Jennifer; Cluzeau, Daniel

    2016-04-01

    Several ecosystem services provided by viticultural landscapes result from interactions between soil organisms and soil parameters. However, to what extent different soil cultivation intensities in vineyards compromise soil organisms and their interactions between soil physical and hydrological properties is not well understood. In this study we examined (i) to what extent different soil management intensities affect the activity and diversity of soil biota (earthworms, Collembola, litter decomposition), and (ii) how soil physical and hydrological properties influence these interactions, or vice versa. Investigating 16 vineyards in Austria, earthworms were assessed by hand sorting, Collembola via pitfall trapping and soil coring, litter decomposition by using the tea bag method. Additionally, soil physical (water infiltration, aggregate stability, porosity, bulk density, soil texture) and chemical (pH, soil carbon content, cation exchange capacity, potassium, phosphorus) parameters were assessed. Results showed complex ecological interactions between soil biota and various soil characteristics altered by management intensity. These investigations are part of the transdisciplinary BiodivERsA project VineDivers and will ultimately lead into management recommendations for various stakeholders.

  13. Desert gerbils affect bacterial composition of soil.

    PubMed

    Kuznetsova, Tatyana A; Kam, Michael; Khokhlova, Irina S; Kostina, Natalia V; Dobrovolskaya, Tatiana G; Umarov, Marat M; Degen, A Allan; Shenbrot, Georgy I; Krasnov, Boris R

    2013-11-01

    Rodents affect soil microbial communities by burrow architecture, diet composition, and foraging behavior. We examined the effect of desert rodents on nitrogen-fixing bacteria (NFB) communities by identifying bacteria colony-forming units (CFU) and measuring nitrogen fixation rates (ARA), denitrification (DA), and CO2 emission in soil from burrows of three gerbil species differing in diets. Psammomys obesus is folivorous, Meriones crassus is omnivorous, consuming green vegetation and seeds, and Dipodillus dasyurus is predominantly granivorous. We also identified NFB in the digestive tract of each rodent species and in Atriplex halimus and Anabasis articulata, dominant plants at the study site. ARA rates of soil from burrows of the rodent species were similar, and substantially lower than control soil, but rates of DA and CO2 emission differed significantly among burrows. Highest rates of DA and CO2 emission were measured in D. dasyurus burrows and lowest in P. obesus. CFU differed among bacteria isolates, which reflected dietary selection. Strains of cellulolytic representatives of the family Myxococcaceae and the genus Cytophaga dominated burrows of P. obesus, while enteric Bacteroides dominated burrows of D. dasyurus. Burrows of M. crassus contained both cellulolytic and enteric bacteria. Using discriminant function analysis, differences were revealed among burrow soils of all rodent species and control soil, and the two axes accounted for 91 % of the variance in bacterial occurrences. Differences in digestive tract bacterial occurrences were found among these rodent species. Bacterial colonies in P. obesus and M. crassus burrows were related to bacteria of A. articulata, the main plant consumed by both species. In contrast, bacteria colonies in the burrow soil of D. dasyurus were related to bacteria in its digestive tract. We concluded that gerbils play an important role as ecosystem engineers within their burrow environment and affect the microbial complex of

  14. Factors affecting sequestration and bioavailability of phenanthrene in soils

    SciTech Connect

    White, J.C.; Kelsey, J.W.; Hatzinger, P.B.; Alexander, M.

    1997-10-01

    A study was conducted to determine factors affecting the sequestration and changes in bioavailability as phenanthrene persists in soils. Phenanthrene became sequestered in seven soils differing appreciably in organic matter and clay content as measured by earthworm uptake, bacterial mineralization, or extractability. Phenanthrene also became sequestered as it aged in soil aggregates of various sizes as measured by decline in availability to a bacterium, a mild extractant, or both. Wetting and drying a soil during aging reduced the amount of phenanthrene recovered by a mild extractant and the rate and extent of bacterial mineralization of the hydrocarbon. After biodegradation of phenanthrene added to the soil, more of the compound remained if it had been aged than if it had not been aged. Wetting and drying the soil during aging further increased the amount of phenanthrene remaining after biodegradation. The rate and extent of bacterial mineralization of phenanthrene were less in leached than in unleached soil. Aging/sequestration is thus markedly affected by soil properties and environmental factors.

  15. How forest fire affects the chemical properties of Andisols

    NASA Astrophysics Data System (ADS)

    Neris, Jonay; Hernández-Moreno, José Manuel; Tejedor, Marisa; Jiménez, Concepción

    2013-04-01

    Forest fires affect soil physical, chemical and mineralogical properties. However, the magnitude of these changes depends on both fire properties, such as the peak temperature reached and duration or depth achieved; and initial soil properties (soil type) as for example soil moisture, organic matter content or soil structure characteristics. Although many works have studied the effects of fire on the chemical properties of different soil types, its effects on Andisols properties have been omitted until now. Taking into account the high susceptibility to drying processes showed by the properties of Andisols affected by land use changes, it could be expected that the fire effects on their chemical properties may differ from those shown by other types of soil. In this study, the main chemical properties in addition to the specific andic properties of burned pine forest Andisols were compared to their unburned control. The chemical properties of ashes found after fire at the soil surface were also studied. The results show a slightly increase in EC and pH after the fire due mainly to the higher content of cations of the soil solution. Ashes derived from the vegetation and soil organic matter consumption by fire could be the main source of these elements in the soils after a fire, as they showed a high cation content. However, the rise in EC and pH is lower than the reported by most authors for other soil types. This behaviour could be related to the higher organic matter content of this soils, even after fire, and the buffering effect of organic compounds on the soil EC and pH changes after the fire. As other authors have shown, a decrease in both the total and active organic content after the fire was also observed as a result of the fire event. The specific andic properties of Andisols were also affected. The P retention of these soils slightly declines as a consequence of fire, while the content of short-range-order products was also modified, but no statistically

  16. Spatial heterogeneity of soil biochar content affects soil quality and wheat growth and yield.

    PubMed

    Olmo, Manuel; Lozano, Ana María; Barrón, Vidal; Villar, Rafael

    2016-08-15

    Biochar (BC) is a carbonaceous material obtained by pyrolysis of organic waste materials and has been proposed as a soil management strategy to mitigate global warming and to improve crop productivity. Once BC has been applied to the soil, its imperfect and incomplete mixing with soil during the first few years and the standard agronomic practices (i.e. tillage, sowing) may generate spatial heterogeneity of the BC content in the soil, which may have implications for soil properties and their effects on plant growth. We investigated how, after two agronomic seasons, the spatial heterogeneity of olive-tree prunings BC applied to a vertisol affected soil characteristics and wheat growth and yield. During the second agronomic season and just before wheat germination, we determined the BC content in the soil by an in-situ visual categorization based on the soil darkening, which was strongly correlated to the BC content of the soil and the soil brightness. We found a high spatial heterogeneity in the BC plots, which affected soil characteristics and wheat growth and yield. Patches with high BC content showed reduced soil compaction and increased soil moisture, pH, electrical conductivity, and nutrient availability (P, Ca, K, Mn, Fe, and Zn); consequently, wheat had greater tillering and higher relative growth rate and grain yield. However, if the spatial heterogeneity of the soil BC content had not been taken into account in the data analysis, most of the effects of BC on wheat growth would not have been detected. Our study reveals the importance of taking into account the spatial heterogeneity of the BC content. PMID:27110980

  17. Nitrogen starvation affects bacterial adhesion to soil

    PubMed Central

    Borges, Maria Tereza; Nascimento, Antônio Galvão; Rocha, Ulisses Nunes; Tótola, Marcos Rogério

    2008-01-01

    One of the main factors limiting the bioremediation of subsoil environments based on bioaugmentation is the transport of selected microorganisms to the contaminated zones. The characterization of the physiological responses of the inoculated microorganisms to starvation, especially the evaluation of characteristics that affect the adhesion of the cells to soil particles, is fundamental to anticipate the success or failure of bioaugmentation. The objective of this study was to investigate the effect of nitrogen starvation on cell surface hydrophobicity and cell adhesion to soil particles by bacterial strains previously characterized as able to use benzene, toluene or xilenes as carbon and energy sources. The strains LBBMA 18-T (non-identified), Arthrobacter aurescens LBBMA 98, Arthrobacter oxydans LBBMA 201, and Klebsiella sp. LBBMA 204–1 were used in the experiments. Cultivation of the cells in nitrogen-deficient medium caused a significant reduction of the adhesion to soil particles by all the four strains. Nitrogen starvation also reduced significantly the strength of cell adhesion to the soil particles, except for Klebsiella sp. LBBMA 204–1. Two of the four strains showed significant reduction in cell surface hydrophobicity. It is inferred that the efficiency of bacterial transport through soils might be potentially increased by nitrogen starvation. PMID:24031246

  18. Soil Chemical Properties of an Urban Catchment

    NASA Astrophysics Data System (ADS)

    Yesilonis, I. D.; Pouyat, R.; Smith, B.; Kloze, A.; Donovan, K.; Norris, L.

    2006-05-01

    Soils are affected by urbanization directly and indirectly from a variety of sources. Within the urban environment, landuse and cover may affect soil chemical properties. This study was conducted to determine if soil metals and nutrient concentrations vary by landuse and cover (ecotope) categories. Surface soil metals and nutrients were measured in a sewershed named 263 located in southwest Baltimore City. The 65 soil samples to a depth of 5 cm were taken randomly stratified by an ecotope classification system. The five classes were 1) constructed; 2) disturbed: mixed, annual and perennial; 3) ornamental use: annual vegetation; 4) ornamental use: mixed vegetation; and 5) ornamental use: perennial vegetation. The soils were digested with nitric acid and analyzed for a suite of metals and nutrients using an ICP-MS. The elemental sources were speculated using toxic release inventory stacks, geology/soils, and roads. The ecotope "disturbed" classes had higher concentrations of S, Cu, Ca, and Pb; and the "ornamental" classes had higher concentrations of As and Cr. In conclusion, soil metal and nutrient concentrations deposited from the urban environment differed among ecotope classes.

  19. Effect of cryogel on soil properties

    NASA Astrophysics Data System (ADS)

    Altunina, L. K.; Fufaeva, M. S.; Filatov, D. A.; Svarovskaya, L. I.; Rozhdestvenskii, E. A.; Gan-Erdene, T.

    2014-05-01

    Samples from the A1 and A1A2 horizons of sandy loamy gray forest soil containing 3.1% organic matter have been mixed with a 5% solution of polyvinyl alcohol (PVA) at a ratio of 7 : 1 under laboratory conditions. The samples were frozen at -20°C in a refrigerator; after a freezing-thawing cycle, the evaporation of water from their surface, their thermal conductivity coefficient, their elasticity modulus, and other properties were studied. It has been experimentally found that the thermal conductivity coefficient of cryostructured soil is lower than that of common soil by 25%. It has been shown that the cryostructured soil retains water for a longer time and that the water evaporation rate from its surface is significantly lower compared to the control soil. Cryogel has no negative effect on the catalase activity of soil; it changes the physical properties of soils and positively affects the population of indigenous soil microflora and the growth of the sown plants.

  20. Soil Resources Area Affects Herbivore Health

    PubMed Central

    Garner, James A.; Ahmad, H. Anwar; Dacus, Chad M.

    2011-01-01

    Soil productivity effects nutritive quality of food plants, growth of humans and animals, and reproductive health of domestic animals. Game-range surveys sometimes poorly explained variations in wildlife populations, but classification of survey data by major soil types improved effectiveness. Our study evaluates possible health effects of lower condition and reproductive rates for wild populations of Odocoileus virginianus Zimmerman (white-tailed deer) in some physiographic regions of Mississippi. We analyzed condition and reproductive data for 2400 female deer from the Mississippi Department of Wildlife, Fisheries, and Parks herd health evaluations from 1991–1998. We evaluated age, body mass (Mass), kidney mass, kidney fat mass, number of corpora lutea (CL) and fetuses, as well as fetal ages. Region affected kidney fat index (KFI), which is a body condition index, and numbers of fetuses of adults (P ≤ 0.001). Region affected numbers of CL of adults (P ≤ 0.002). Mass and conception date (CD) were affected (P ≤ 0.001) by region which interacted significantly with age for Mass (P ≤ 0.001) and CD (P < 0.04). Soil region appears to be a major factor influencing physical characteristics of female deer. PMID:21776246

  1. Effects of Biochar Amendment on Soil Properties and Soil Carbon Sequestration

    NASA Astrophysics Data System (ADS)

    Zhang, R.; Zhu, S.

    2015-12-01

    Biochar addition to soils potentially affects various soil properties and soil carbon sequestration, and these effects are dependent on biochars derived from different feedstock materials and pyrolysis processes. The objective of this study was to investigate the effects of amendment of different biochars on soil physical and biological properties as well as soil carbon sequestration. Biochars were produced with dairy manure and woodchip at temperatures of 300, 500, and 700°C, respectively. Each biochar was mixed at 5% (w/w) with a forest soil and the mixture was incubated for 180 days, during which soil physical and biological properties, and soil respiration rates were measured. Results showed that the biochar addition significantly enhanced the formation of soil macroaggregates at the early incubation time. The biochar application significantly reduced soil bulk density, increased the amount of soil organic matter, and stimulated microbial activity and soil respiration rates at the early incubation stage. Biochar applications improved water retention capacity, with stronger effects by biochars produced at higher pyrolysis temperatures. At the same suction, the soil with woodchip biochars possessed higher water content than with the dairy manure biochars. Biochar addition significantly affected the soil physical and biological properties, which resulted in different soil carbon mineralization rates and the amount of soil carbon storage.

  2. Soil microbial community dynamics as influenced by composted dairy manure, soil properties and landscape position

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Understanding factors that affect plant growth, whether it is manure addition, season, or soil-type and landscape variability may also impact soil microbial activity, biomass and community structure. Thus an in situ study was conducted to evaluate microbiological properties of three different soil t...

  3. Pesticide interactions with soils affected by olive oil mill wastewater

    NASA Astrophysics Data System (ADS)

    Keren, Yonatan; Bukhanovsky, Nadezhda; Borisover, Mikhail

    2013-04-01

    Soil pesticide sorption is well known to affect the fate of pesticides, their bioavailability and the potential to contaminate air and water. Soil - pesticide interactions may be strongly influenced by soil organic matter (SOM) and organic matter (OM)-rich soil amendments. One special OM source in soils is related to olive oil production residues that may include both solid and liquid wastes. In the Mediterranean area, the olive oil production is considered as an important field in the agricultural sector. Due to the significant rise in olive oil production, the amount of wastes is growing respectively. Olive oil mill waste water (OMWW) is the liquid byproduct in the so-called "three phase" technological process. Features of OMWW include the high content of fatty aliphatic components and polyphenols and their often-considered toxicity. One way of OMWW disposal is the land spreading, e.g., in olive orchards. The land application of OMWW (either controlled or not) is supposed to affect the multiple soil properties, including hydrophobicity and the potential of soils to interact with pesticides. Therefore, there is both basic and applied interest in elucidating the interactions between organic compounds and soils affected by OMWW. However, little is known about the impact of OMWW - soil interactions on sorption of organic compounds, and specifically, on sorption of agrochemicals. This paper reports an experimental study of sorption interactions of a series of organic compounds including widely used herbicides such as diuron and simazine, in a range of soils that were affected by OMWW (i) historically or (ii) in the controlled land disposal experiments. It is demonstrated that there is a distinct increase in apparent sorption of organic chemicals in soils affected by OMWW. In selected systems, this increase may be explained by increase in SOM content. However, the SOM quality places a role: the rise in organic compound - soil interactions may both exceed the SOM

  4. Soil information requirements for humanitarian demining: the case for a soil properties database

    NASA Astrophysics Data System (ADS)

    Das, Yogadhish; McFee, John E.; Russell, Kevin L.; Cross, Guy; Katsube, T. John

    2003-09-01

    Landmines are buried typically in the top 30 cm of soil. A number of physical, chemical and electromagnetic properties of this near-surface layer of ground will potentially affect the wide range of technologies under development worldwide for landmine detection and neutralization. Although standard soil survey information, as related to conventional soil classification, is directed toward agricultural and environmental applications, little or no information seems to exist in a form that is directly useful to humanitarian demining and the related R&D community. Thus, there is a general need for an information database devoted specifically to relevant soil properties, their geographic distribution and climate-driven variability. A brief description of the various detection technologies is used to introduce the full range of related soil properties. Following a general description of the need to establish a comprehensive soil property database, the discussion is then narrowed to soil properties affecting electromagnetic induction metal detectors - a problem of much restricted scope but of immediate and direct relevance to humanitarian demining. In particular, the complex magnetic susceptibility and, to a lesser degree, electrical conductivity of the host soil influence the performance of these widely used tools, and in the extreme instance, can render detectors unusable. A database comprising these properties for soils of landmine-affected countries would assist in predicting local detector performance, planning demining operations, designing and developing improved detectors and establishing realistic and representative test-evaluation facilities. The status of efforts made towards developing a database involving soil electromagnetic properties is reported.

  5. Soil moisture and properties estimation by assimilating soil temperatures using particle batch smoother: A new perspective for DTS

    NASA Astrophysics Data System (ADS)

    Dong, J.; Steele-Dunne, S. C.; Ochsner, T. E.; Van De Giesen, N.

    2015-12-01

    Soil moisture, hydraulic and thermal properties are critical for understanding the soil surface energy balance and hydrological processes. Here, we will discuss the potential of using soil temperature observations from Distributed Temperature Sensing (DTS) to investigate the spatial variability of soil moisture and soil properties. With DTS soil temperature can be measured with high resolution (spatial <1m, and temporal < 1min) in cables up to kilometers in length. Soil temperature evolution is primarily controlled by the soil thermal properties, and the energy balance at the soil surface. Hence, soil moisture, which affects both soil thermal properties and the energy that participates the evaporation process, is strongly correlated to the soil temperatures. In addition, the dynamics of the soil moisture is determined by the soil hydraulic properties.Here we will demonstrate that soil moisture, hydraulic and thermal properties can be estimated by assimilating observed soil temperature at shallow depths using the Particle Batch Smoother (PBS). The PBS can be considered as an extension of the particle filter, which allows us to infer soil moisture and soil properties using the dynamics of soil temperature within a batch window. Both synthetic and real field data will be used to demonstrate the robustness of this approach. We will show that the proposed method is shown to be able to handle different sources of uncertainties, which may provide a new view of using DTS observations to estimate sub-meter resolution soil moisture and properties for remote sensing product validation.

  6. Different Degrees of Plant Invasion Significantly Affect the Richness of the Soil Fungal Community

    PubMed Central

    Si, Chuncan; Liu, Xueyan; Wang, Congyan; Wang, Lei; Dai, Zhicong; Qi, Shanshan; Du, Daolin

    2013-01-01

    Several studies have shown that soil microorganisms play a key role in the success of plant invasion. Thus, ecologists have become increasingly interested in understanding the ecological effects of biological invasion on soil microbial communities given continuing increase in the effects of invasive plants on native ecosystems. This paper aims to provide a relatively complete depiction of the characteristics of soil microbial communities under different degrees of plant invasion. Rhizospheric soils of the notorious invasive plant Wedelia trilobata with different degrees of invasion (uninvaded, low-degree, and high-degree using its coverage in the invaded ecosystems) were collected from five discrete areas in Hainan Province, P. R. China. Soil physicochemical properties and community structure of soil microorganisms were assessed. Low degrees of W. trilobata invasion significantly increased soil pH values whereas high degrees of invasion did not significantly affected soil pH values. Moreover, the degree of W. trilobata invasion exerted significant effects on soil Ca concentration but did not significantly change other indices of soil physicochemical properties. Low and high degrees of W. trilobata invasion increased the richness of the soil fungal community but did not pose obvious effects on the soil bacterial community. W. trilobata invasion also exerted obvious effects on the community structure of soil microorganisms that take part in soil nitrogen cycling. These changes in soil physicochemical properties and community structure of soil microbial communities mediated by different degrees of W. trilobata invasion may present significant functions in further facilitating the invasion process. PMID:24392015

  7. Lunar soil properties and soil mechanics

    NASA Technical Reports Server (NTRS)

    Mitchell, J. K.; Houston, W. N.; Hovland, H. J.

    1972-01-01

    The study to identify and define recognizable fabrics in lunar soil in order to determine the history of the lunar regolith in different locations is reported. The fabric of simulated lunar soil, and lunar soil samples are discussed along with the behavior of simulated lunar soil under dynamic and static loading. The planned research is also included.

  8. Effects of long-term soil and crop management on soil hydraulic properties for claypan soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Regional and national soil maps have been developed along with associated soil property databases to assist users in making land management decisions based on soil characteristics. These soil properties include average values from soil characterization for each soil series. In reality, these propert...

  9. Effect of biosolid waste compost on soil respiration in salt-affected soils

    NASA Astrophysics Data System (ADS)

    Raya, Silvia; Gómez, Ignacio; García, Fuensanta; Navarro, José; Jordán, Manuel Miguel; Belén Almendro, María; Martín Soriano, José

    2013-04-01

    respiration, compost, electrical conductivity, salinization, Bac-Trac References: Abdelbasset Lakhdar, Mokded Rabhi, Tahar Ghnaya, Francesco Montemurro, Naceur Jedidi , Chedly Abdelly. Effectiveness of compost use in salt-affected soil. Journal of Hazardous Materials 171 (2009) pp 29-37. M. Tejada, C. Garcia, J.L. Gonzalez , M.T. Hernandez . Use of organic amendment as a strategy for saline soil remediation:Influence on the physical, chemical and biological properties of soil. Soil Biology & Biochemistry 38 (2006) pp 1413-1421. I. Gomez; J.M. Disla Soriano; J. Navarro-Pedreño; F. García-Orenes; M.B. Almendro-Candel; M.M. Jordan. Quantification of soil respiration in different saline soil of Alicante (Spain). EGU General Assembly (2012). Viena. Ed. Geophysycal Research Abstracts. Vol 14 EGU2012-2399,(2012). (Acknowledgements: This work was supported by the Spanish MICINN. Project Ref.: CGL2009-11194)

  10. Quantifying intrinsic and extrinsic factors affecting soil erodibility

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil erodibility has traditionally been conceived as a soil dependent parameter that can be quantified from intrinsic soil properties that usually stay constant. Development of erosion prediction equations, from the empirical-based Universal Soil Loss Equation (USLE) to a more processed-based Water ...

  11. Factors Affecting Performance of Soil Termiticides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Applying liquid insecticide to soil under and around structures is one of the most widely used methods of subterranean termite prevention and control. Failure of soil termiticide treatments is often related to factors other than the active ingredient. Efficacy and longevity of soil treatments vary g...

  12. Tillage effects on soil physical properties, sugarbeet yield and quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tillage influences the soil-water-plant ecosystem thereby affecting crop yield and quality. The effects of tillage on soil physical properties, sugarbeet (Beta vulgaris L.) yield and quality were evaluated. A field study comprises of three tillage practices: no tillage (NT) shallow (ST) of 10-cm and...

  13. Soil-Structural Stability as Affected by Clay Mineralogy, Soil Texture and Polyacrylamide Application

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil-structural stability (expressed in terms of aggregate stability and pore size distribution) depends on (i) soil inherent properties, (ii) extrinsic condition prevailing in the soil that may vary temporally and spatially, and (iii) addition of soil amendments. Different soil management practices...

  14. Effects of Long-term Soil and Crop Management on Soil Hydraulic Properties for Claypan Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Regional and national soil maps and associated databases of soil properties have been developed to help land managers make decisions based on soil characteristics. Hydrologic modelers also utilize soil hydraulic properties provided in these databases, in which soil characterization is based on avera...

  15. Vital Soil: Function, Value and Properties.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This article is a review of the book, Vital Soil: Function, Value and Properties. Soil vitality has been defined as the ability of soil ecosystems to stay in balance in a changing world. The soil environment and the life that it supports developed over centuries and millennia, but careless human ac...

  16. Monitoring the Remediation of Salt-Affected Soils and Groundwater

    NASA Astrophysics Data System (ADS)

    Bentley, L. R.; Callaghan, M. V.; Cey, E. E.

    2008-12-01

    Salt-affected soil is one of the most common environmental issues facing the petroleum hydrocarbon industry. Large quantities of brines are often co-produced with gas and oil and have been introduced into the environment through, for example, flare pits, drilling operations and pipe line breaks. Salt must be flushed from the soil and tile drain systems can be used to collect salt water which is then be routed for disposal. A flushing experiment over a 2 m deep tile drain system is being monitored by arrays of tensiometers, repeated soil coring, direct push electrical conductivity profiles (PTC), electromagnetic surveys and electrical resistivity tomography (ERT) surveys. Water table elevation is monitored with pressure transducers. Thermocouple arrays provide temperature profiles that are used to adjust electrical conductivity data to standard temperature equivalents. A 20 m by 20 m plot was deep tilled and treated with soil amendments. Numerous infiltration tests were conducted inside and outside the plot area using both a tension infiltrometer and Guelph permeameter to establish changes in soil hydraulic properties and macroporosity as a result of deep tillage. The results show that till greatly diminished the shallow macroporosity and increased the matrix saturated hydraulic conductivity. A header system is used to evenly flood the plot with 10 m3 of water on each of three consecutive days for an approximate total of 7.5 cm of water. The flood event is being repeated four times over a period of 6 weeks. Baseline PTC and ERT surveys show that the salt is concentrated in the upper 2 to 3 m of soil. Tensiometer data show that the soil at 30 cm depth responds within 2 to 3 hours to flooding events once the soil is wetted and begins to dry again after one week. Soil suction at 1.5 m does not show immediate response to the daily flooding events, but is steadily decreasing in response to the flooding and rainfall events. An ERT survey in October will provide the first

  17. Measurement of dielectric and magnetic properties of soil

    SciTech Connect

    Patitz, W.E.; Brock, B.C.; Powell, E.G.

    1995-11-01

    The possibility of subsurface imaging using SAR technology has generated a considerable amount of interest in recent years. One requirement for the successful development of a subsurface imagin system is an understanding of how the soil affects the signal. In response to a need for an electromagnetic characterization of the soil properties, the Radar/Antenna department has developed a measurement system which determines the soils complex electric permittivity and magnetic permeability at UHF frequencies. The one way loss in dB is also calculated using the measured values. There are many reports of measurements of the electric properties of soil in the literature. However, most of these are primarily concerned with measuring only a real dielectric constant. Because some soils have ferromagnetic constituents it is desirable to measure both the electric and magnetic properties of the soil.

  18. Predicting radiocaesium sorption characteristics with soil chemical properties for Japanese soils.

    PubMed

    Uematsu, Shinichiro; Smolders, Erik; Sweeck, Lieve; Wannijn, Jean; Van Hees, May; Vandenhove, Hildegarde

    2015-08-15

    The high variability of the soil-to-plant transfer factor of radiocaesium (RCs) compels a detailed analysis of the radiocaesium interception potential (RIP) of soil, which is one of the specific factors ruling the RCs transfer. The range of the RIP values for agricultural soils in the Fukushima accident affected area has not yet been fully surveyed. Here, the RIP and other major soil chemical properties were characterised for 51 representative topsoils collected in the vicinity of the Fukushima contaminated area. The RIP ranged a factor of 50 among the soils and RIP values were lower for Andosols compared to other soils, suggesting a role of soil mineralogy. Correlation analysis revealed that the RIP was most strongly and negatively correlated to soil organic matter content and oxalate extractable aluminium. The RIP correlated weakly but positively to soil clay content. The slope of the correlation between RIP and clay content showed that the RIP per unit clay was only 4.8 mmol g(-1) clay, about threefold lower than that for clays of European soils, suggesting more amorphous minerals and less micaceous minerals in the clay fraction of Japanese soils. The negative correlation between RIP and soil organic matter may indicate that organic matter can mask highly selective sorption sites to RCs. Multiple regression analysis with soil organic matter and cation exchange capacity explained the soil RIP (R(2)=0.64), allowing us to map soil RIP based on existing soil map information. PMID:25897723

  19. Can transgenic maize affect soil microbial communities?

    PubMed

    Mulder, Christian; Wouterse, Marja; Raubuch, Markus; Roelofs, Willem; Rutgers, Michiel

    2006-09-29

    The aim of the experiment was to determine if temporal variations of belowground activity reflect the influence of the Cry1Ab protein from transgenic maize on soil bacteria and, hence, on a regulatory change of the microbial community (ability to metabolize sources belonging to different chemical guilds) and/or a change in numerical abundance of their cells. Litter placement is known for its strong influence on the soil decomposer communities. The effects of the addition of crop residues on respiration and catabolic activities of the bacterial community were examined in microcosm experiments. Four cultivars of Zea mays L. of two different isolines (each one including the conventional crop and its Bacillus thuringiensis cultivar) and one control of bulk soil were included in the experimental design. The growth models suggest a dichotomy between soils amended with either conventional or transgenic maize residues. The Cry1Ab protein appeared to influence the composition of the microbial community. The highly enhanced soil respiration observed during the first 72 h after the addition of Bt-maize residues can be interpreted as being related to the presence of the transgenic crop residues. This result was confirmed by agar plate counting, as the averages of the colony-forming units of soils in conventional treatments were about one-third of those treated with transgenic straw. Furthermore, the addition of Bt-maize appeared to induce increased microbial consumption of carbohydrates in BIOLOG EcoPlates. Three weeks after the addition of maize residues to the soils, no differences between the consumption rate of specific chemical guilds by bacteria in soils amended with transgenic maize and bacteria in soils amended with conventional maize were detectable. Reaped crop residues, comparable to post-harvest maize straw (a common practice in current agriculture), rapidly influence the soil bacterial cells at a functional level. Overall, these data support the existence of short

  20. Can Transgenic Maize Affect Soil Microbial Communities?

    PubMed Central

    Mulder, Christian; Wouterse, Marja; Raubuch, Markus; Roelofs, Willem; Rutgers, Michiel

    2006-01-01

    The aim of the experiment was to determine if temporal variations of belowground activity reflect the influence of the Cry1Ab protein from transgenic maize on soil bacteria and, hence, on a regulatory change of the microbial community (ability to metabolize sources belonging to different chemical guilds) and/or a change in numerical abundance of their cells. Litter placement is known for its strong influence on the soil decomposer communities. The effects of the addition of crop residues on respiration and catabolic activities of the bacterial community were examined in microcosm experiments. Four cultivars of Zea mays L. of two different isolines (each one including the conventional crop and its Bacillus thuringiensis cultivar) and one control of bulk soil were included in the experimental design. The growth models suggest a dichotomy between soils amended with either conventional or transgenic maize residues. The Cry1Ab protein appeared to influence the composition of the microbial community. The highly enhanced soil respiration observed during the first 72 h after the addition of Bt-maize residues can be interpreted as being related to the presence of the transgenic crop residues. This result was confirmed by agar plate counting, as the averages of the colony-forming units of soils in conventional treatments were about one-third of those treated with transgenic straw. Furthermore, the addition of Bt-maize appeared to induce increased microbial consumption of carbohydrates in BIOLOG EcoPlates. Three weeks after the addition of maize residues to the soils, no differences between the consumption rate of specific chemical guilds by bacteria in soils amended with transgenic maize and bacteria in soils amended with conventional maize were detectable. Reaped crop residues, comparable to post-harvest maize straw (a common practice in current agriculture), rapidly influence the soil bacterial cells at a functional level. Overall, these data support the existence of short

  1. Can surfactants affect management of non-water repellent soils?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surfactants affect the water relations of water repellent soils but may or may not affect those of wettable soils. We studied the effects of three surfactants, Aquatrols IrrigAid Gold®, an ethylene oxide/propylene oxide block copolymer, and an alkyl polyglycoside, along with untreated tap water as ...

  2. Impact of soil properties for European climate simulations

    NASA Astrophysics Data System (ADS)

    Guillod, B. P.; Davin, E. L.; Kündig, C.; Smiatek, G.; Seneviratne, S. I.

    2012-04-01

    Soil properties have a strong influence on the terrestrial water cycle, in particular by influencing soil water distribution and dynamics. This in turn affects evapotranspiration from the land to the atmosphere and thus climate conditions. While many studies have looked at the climatic influence of vegetation characteristics/land cover change, fewer investigated the importance of soil properties for climate, although soil properties can also be indirectly altered by land use changes. In this study, we investigate the influence of soil properties on the European climate using a regional climate model. First, two simulations using two different soil maps are investigated: the soil map of the world from the Food and Agricultural Organization (FAO) and the European Soil Database (ESDB) from the European Commission Joint Research Center (JRC). These simulations highlight the importance of the specified soil texture in summer, with differences of up to 2°C in mean 2-meter temperature and 20% in precipitation due to changes in the partitioning of energy at the land surface into sensible and latent heat flux. In an additional set of experiments, we modify different sets of soil physical parameters to evaluate their relative importance. Hydraulic diffusivity as well as field capacity and plant wilting point are shown to play an important role, unlike hydraulic conductivity. We highlight the importance of the vertical profile of soil moisture for evapotranspiration as it impacts soil moisture dynamics. Our study highlights the importance of soil texture and related parameters for climate simulations. Given the uncertainty associated with the geographical distribution of soil texture, efforts to improve existing databases and their integration in climate and hydrological models are needed. Tackling unresolved issues in land-surface modeling related to the high variability of soil parameters, both spatially and within a soil textural class, would benefit a large community and

  3. Effects of Particle Size and Shape, and Soil Structure on Thermal Properties of Non-aggregated and Aggregated Soils

    NASA Astrophysics Data System (ADS)

    Kamoshida, T.; Hamamoto, S.; Kawamoto, K.; Sakaki, T.; Komatsu, T.; Hu, Q.

    2012-12-01

    Thermal properties including thermal conductivity and heat capacity are very important for understanding heat transport processes in landfill site cover soil to control the microbial processes in the cover soil. Previous studies have shown effects of soil conditions such as moisture content and degree of compaction on the thermal properties for differently-textured soils. However, there are few studies on the relations between the thermal properties and micro-scale soil information such as particle size and shape although the size and shape of soil particles highly affect soil packing configuration. In addition, it is not fully understood that soil structure (i.e., aggregate structure) affects behaviors of thermal properties. In this study, non-aggregated (sandy) and aggregated soils with different size fractions at variably-saturated conditions were used for measuring thermal properties. Micro-scale characterizations of soil-pore structure and soil particle configuration using a X-ray CT device were also performed for sandy soils. For sandy soils, the relation between measured thermal properties and mineral composition (i.e., quartz content), roundness/sphericity of soil particles, and particle size, and solid-phase tortuosity based on X-ray CT images, were investigated. For aggregated soils, the measured thermal conductivities at variably-saturated conditions were discussed based on the water retention characteristics and pore-size distribution in inter- and intra-aggregate pore regions.

  4. SOIL COMPACTION AND POULTRY LITTER EFFECTS ON FACTORS AFFECTING NITROGEN AVAILABILITY IN A CLAYPAN SOIL

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil compaction may affect N mineralization and the subsequent fate of N in agroecosystems. Laboratory incubation and field experiments were conducted to determine the effects of surface soil compaction on soil N mineralization in a claypan soil amended with poultry litter (i.e., turkey excrement mi...

  5. Determination of soil hydraulic properties using the soil pedostructure concept

    NASA Astrophysics Data System (ADS)

    Braudeau, E.; Mohtar, R. H.

    2003-04-01

    The observed soil water properties such as Field Capacity, Permanent Wilting Point, Water Potential and Hydraulic Conductivity are expressions of the internal soil structure and are all connected to Water Matric Potential. Our research describes these properties in a context of a new concept of the internal hierarchal soil structure and the tension that exists inside the soil matrix due to the presence of clay particles. This concept will be demonstrated using laboratory experiments of simultaneous and continuous measurements of the soil water potential curve and of the shrinkage and swelling curves. The soil shrinkage curve has been used to explain the hydraulic and functional properties of soil with its assembly of swelling aggregates according to the conceptual pedostructure model. In that model two water pools held in two distinguished macro- and micro-porosity are described in addition to specific characteristics of the primary peds such air entry point, maximum swelling, and plasmic porosity. The water potential will be calculated according to these water pools. In this context, the empirical agronomical soil physical properties like wilting point and field capacity, will be defined relative to a particular hydrostructural state of the soil rather than to a hypothetical soil water potential. These properties could then be accurately determined starting from the measured shrinkage curve determined by retractometry.

  6. Deriving soil thermal properties from continuous soil profile observations in southern France

    NASA Astrophysics Data System (ADS)

    Calvet, Jean-Christophe

    2015-04-01

    Soil moisture is the main driver of temporal changes in values of the soil thermal conductivity. The latter is a key variable in land surface models (LSMs) used in hydrometeorology, for the simulation of the vertical profile of soil temperature, in relation to soil moisture. Shortcomings in soil thermal conductivity models tend to limit the impact of improving the simulation of soil moisture in LSMs. Models of the thermal conductivity of soils are affected by uncertainties, especially in the representation of the impact of soil properties such as the volumetric fraction of quartz (q), soil organic matter (FSOM), and gravel. As soil organic matter and gravel are often neglected in LSMs, the soil thermal conductivity models used in most LSMs represent the mineral fine earth, only. Moreover, there is no map of q and it is often assumed that this quantity is equal to the volumetric fraction of sand (Fsand). In this study, q values are derived by reverse modelling from the continuous soil moisture and soil temperature sub-hourly observations of the SMOSMANIA network at 18 grassland sites in southern France, from 2009 to 2013. The soil temperature observations are used to retrieve the soil thermal diffusivity (Dh) at a depth of 0.10 m by solving the thermal diffusion equation. The soil moisture and Dh values are then used together with the measured soil properties to retrieve effective soil thermal conductivity (L) values. For 15 sites, it is shown that q can be derived from regressed empirical equations using a linear combination of Fsand and FSOM measurements, together with porosity estimates. For three sites, very low values of q and of the L values at saturation (Lsat) are obtained, probably in relation to a high density of grass roots at these sites. The impact of neglecting gravel and organic matter on Lsat, and the impact of uncertainties on the estimation of q are assessed. It is shown that neglecting the soil organic matter has a major impact on Lsat.

  7. Soil warming affects soil organic matter chemistry of all density fractions of a mountain forest soil

    NASA Astrophysics Data System (ADS)

    Schnecker, Jörg; Wanek, Wolfgang; Borken, Werner; Schindlbacher, Andreas

    2016-04-01

    Rising temperatures enhance microbial decomposition of soil organic matter (SOM) and increase thereby the soil CO2 efflux. Elevated microbial activity might differently affect distinct SOM pools, depending on their stability and accessibility. Soil fractions derived from density fractionation have been suggested to represent SOM pools with different turnover times and stability against microbial decomposition. We here investigated the chemical and isotopic composition of bulk soil and three different density fractions of forest soils from a long term warming experiment in the Austrian Alps. At the time of sampling the soils in this experiment had been warmed during the snow-free period for 8 consecutive years. During that time no thermal adaptation of the microbial community could be identified and CO2 release from the soil continued to be elevated by the warming treatment. Our results which included organic C content, total N content, δ13C, δ 14C, δ 15N and the chemical composition, identified by pyrolysis-GC/MS, showed no significant differences in bulk soil between warming treatment and control. The differences in the three individual fractions (free particulate organic matter, occluded particulate organic matter and mineral associated organic matter) were mostly small and the direction of warming induced change was variable with fraction and sampling depth. We did however find statistically significant effects of warming in all density fractions from 0-10 cm depth, 10-20 cm depth or both. Our results also including significant changes in the supposedly more stable mineral associated organic matter fraction where δ 13C values decreased at both sampling depths and the relative proportion of N-bearing compounds decreased at a sampling depth of 10-20 cm. All the observed changes can be attributed to an interplay of enhanced microbial decomposition of SOM and increased root litter input. This study suggests that soil warming destabilizes all density fractions of

  8. Salt-affected soils of Russia: Solved and unsolved problems

    NASA Astrophysics Data System (ADS)

    Pankova, E. I.

    2015-02-01

    Data on salt-affected soils of Russia are analyzed. Three major problems of current research are outlined: (1) adequate diagnosis of soil salinization, (2) mapping and assessment of the areas of salt-affected soils, and (3) monitoring of the state of soil salinization. On the basis of recent publications, priority tasks and challenges for further research in this field are discussed. First, the notion of salt-affected soils should be specified with due respect for the diagnostic criteria of soil salinization. Second, in the assessment of these soils, not only the degree of salinization but also the chemistry of salts and the depth of the upper salt-bearing horizon should be taken into account. Third, to calculate the areas of salt-affected soils and to perform their monitoring, satellite images meeting specified requirements should be used. These requirements depend on the land use and cultivated crops. Modern technologies of the interpretation of satellite images should be applied for these purposes. Recent studies devoted to the monitoring of the salt status of irrigated and virgin soils of arid regions are discussed.

  9. Soil water repellency affects production and transport of CO2 and CH4 in soil

    NASA Astrophysics Data System (ADS)

    Urbanek, Emilia; Qassem, Khalid

    2016-04-01

    Soil moisture is known to be vital in controlling both the production and transport of C gases in soil. Water availability regulates the decomposition rates of soil organic matter by the microorganisms, while the proportion of water/air filled pores controls the transport of gases within the soil and at the soil-atmosphere interface. Many experimental studies and process models looking at soil C gas fluxes assume that soil water is uniformly distributed and soil is easily wettable. Most soils, however, exhibit some degree of soil water repellency (i.e. hydrophobicity) and do not wet spontaneously when dry or moderately moist. They have restricted infiltration and conductivity of water, which also results in extremely heterogeneous soil water distribution. This is a world-wide occurring phenomenon which is particularly common under permanent vegetation e.g. forest, grass and shrub vegetation. This study investigates the effect of soil water repellency on microbial respiration, CO2 transport within the soil and C gas fluxes between the soil and the atmosphere. The results from the field monitoring and laboratory experiments show that soil water repellency results in non-uniform water distribution in the soil which affects the CO2 and CH4 gas fluxes. The main conclusion from the study is that water repellency not only affects the water relations in the soil, but has also a great impact on greenhouse gas production and transport and therefore should be included as an important parameter during the sites monitoring and modelling of gas fluxes.

  10. Communicating soil property variability in heterogeneous soil mapping units

    NASA Astrophysics Data System (ADS)

    Farewell, Timothy

    2014-05-01

    Soil properties and classes can change over very short distances. For the purpose of scale, clarity and field sampling density, soil maps in England and Wales commonly use mapping units which are groupings of taxonomic soil series, commonly found in association with each other in the landscape. These mixed units (Soil Associations), typically contain between 3 and 7 soil series with physical or chemical properties, which can vary across the mapping unit, or may be relatively homogeneous. The degree of variation is not constant between soil properties, for instance, pH may be relatively constant, but volumetric shrinkage potential may be highly variable. Over the past ten years, the number of users of GIS soil property maps has dramatically increased, yet the vast majority of these users do not have a soil or geoscience background. They are instead practitioners in specific industries. As a result, new techniques have been developed to communicate the variation in maps of soil properties to a non-expert audience. GIS data structures allow more flexibility in the reporting of uncertainty or variation in soil mapping units than paper-based maps. Some properties are categorical, others continuous. In England and Wales, the national and regional memberships of soil associations are available, with areal percentages of the comprising soil series being estimated for each association by a combination of expert judgment and field observations. Membership at a local scale can vary considerably from the national average. When summarizing across a whole map unit, for continuous variables, rarely is it appropriate to provide a mean value, or even a weighted average based on membership percentage of the association. Such approaches can make a nonsense of wide-ranging data. For instance a soil association comprising soil series with highly different percentages of sand, silt and clay may result in a 'loamy' mean soil texture which is not reflective of any of the comprising soils

  11. Reduced soil wettability can affect greenhouse gas fluxes

    NASA Astrophysics Data System (ADS)

    Urbanek, Emilia; Qassem, Khalid

    2015-04-01

    Soil moisture is known to be an important factor affecting the carbon (C) dynamics in soils including decomposition of organic matter and exchange of gases like CO2 and CH4 between the soil and the atmosphere. Most studies and process models looking at the soil C dynamics assume, however, that soils are easily wettable and water is relatively uniformly distributed within the soil pores. Most soils, however, do not wet spontaneously when dry or moderately moist, but instead exhibit some degree of soil water repellency (i.e. hydrophobicity), which can restrict infiltration and conductivity of water for weeks or months. This is world-wide occurring phenomenon which affects all soil textural types but is particularly common under permanent vegetation e.g. forest, grass and shrub vegetation. Soil water repellency is most profound during drier seasons, when the soil moisture content is relatively low. Although prolonged contact with water can gradually decrease water repellency, some soils do not recover to being completely wettable even after very wet winter months or substantial rainfall events. It has been recognized that with the predicted climatic changes the phenomenon of soil water repellency will become even more pronounced and severe, additionally it may occur in the areas and climatic zones where the effect have not been currently recognized. One of the main implications of soil water repellency is restricted water infiltration and reduced conductivity, which results in reduced soil water availability for plants and soil biota, even after prolonged periods of rainfall. As the process of C mineralization and consequently CO2 efflux from soil is driven by the accessibility of organic matter to decomposing organisms, which in turn is directly dependent on (i) soil moisture and (ii) soil temperature it is, therefore hypothesised that carbon decomposition and CO2 efflux in water repellent soils will also be affected when soil in the water repellent state. The CO2

  12. Factors Affecting Soil Microbial Community Structure in Tomato Cropping Systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil and rhizosphere microbial communities in agroecosystems may be affected by soil, climate, plant species, and management. We identified some of the most important factors controlling microbial biomass and community structure in an agroecosystem utilizing tomato plants with the following nine tre...

  13. The chemistry of salt-affected soils and waters

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Knowledge of the chemistry of salt affected soils and waters is necessary for management of irrigation in arid and semi-arid regions. In this chapter we review the origin of salts in the landscape, the major chemical reactions necessary for prediction of the soil solution composition, and the use of...

  14. Challenges associated with sampling dynamic soil properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The determination of dynamic soil properties (DSPs) for agricultural practices poses significant challenges, particularly in the context of values derived as part of the National Soil Survey. Although DSPs have been defined as those properties that change over human time scales, limits on the time ...

  15. Hydraulic and mechanical properties of soil aggregates under organic and conventional soil management

    NASA Astrophysics Data System (ADS)

    Wójciga, A.; Kuś, J.; Turski, M.; Lipiec, J.

    2009-04-01

    Variation in hydraulic and mechanical properties of soil aggregates is an important factor affecting water storage and infiltration because the large inter-aggregate pores are dewatered first and the transport of water and solutes is influenced by the properties of the individual aggregates and contacts between them. A high mechanical stability of soil aggregates is fundamental for the maintenance of proper tilth and provides stable traction for farm implements, but limit root growth inside aggregates. The aggregate properties are largely influenced by soil management practices. Our objective was to compare the effects of organic and conventional soil management on hydraulic and mechanical properties of soil aggregates. Experimental fields subjected to long-term organic (14 years) and conventional managements were located on loamy soil at the Institute of Soil Science and Plant Cultivation - National Research Institute in Pulawy, Poland. Soil samples were collected from two soil depths (0-10 cm and 10-20 cm). After air-drying, two size fractions of soil aggregates (15-20 and 30-35 mm) were manually selected and kept in the dried state in a dessicator in order to provide the same boundary conditions. Following properties of the aggregates were determined: porosity (%) using standard wax method, cumulative infiltration Q (mm3 s-1) and sorptivity S (mm s -1/2) of water and ethanol using a tube with a sponge inserted at the tip, wettability (by comparison of sorptivity of water and ethanol) using repellency index R, crushing strength q (MPa) using strength testing device (Zwick/Roell) and calculated by Dexter's formula. All properties were determined in 15 replicates for each treatment, aggregates size and depth. Organic management decreased porosity of soil aggregates and ethanol infiltration. All aggregates revealed rather limited wettability (high repellency index). In most cases the aggregate wettability was lower under conventional than organic soil management

  16. Influence of surface and subsurface tillage on soil physical properties and soil/plant relationships of planted loblolly pine

    SciTech Connect

    D. L. Kelting; H. L. Allen

    2000-05-01

    Soil tillage can improve tree survival and growth by reducing competing vegetation, increasing nutrient availability, improving planting quality, and improving soil physical properties. The authors conducted a tillage study with competition control and nutrient amendments to isolate the physical effects of tillage on tree growth. The objectives of this study were to understand: (1) how tillage affects soil physical properties; (2) the relationships between these properties and root growth; (3) linkages between root growth response and aboveground growth; and (4) tillage effects on aboveground growth. Four replicates of a 2x2 factorial combination of surface (disking) and subsurface (subsoiling) were installed on a well-drained, clay-textured subsoil, soil located on the Piedmont of North Carolina. Disking improved soil physical properties (reduced bulk density and increased aeration porosity) in the surface 20-cm of soil. Subsoiling improved soil physical properties at all depths in the planting row, with improvements still noted at 60-cm from the planting row in the surface 10-cm of soil. Rooting patterns followed the changes in soil physical properties. Despite improvements in soil physical properties and changes in rooting patterns, aboveground tree growth was not affected by tillage. The results of this study point to the need for better diagnostics for identifying sites were tillage is appropriate in situations where fertilization and vegetation control are planned. Potential factors to consider are presence and abundance of old root channels, soil shrink/swell capacity, soil structure, presence and depth to root restricting layers, and historical precipitation records.

  17. The effect of total carbon on microscopic soil properties and implications for crop production

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil structure is a dynamic property affected by physical, chemical, and microbiological processes. Addition of organic matter to soils and the use of different management practices have been reported to impact soil structure and crop production. Moderation in soil temperature and increases in mic...

  18. Farm-scale variation of soil quality indices and association with edaphic properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil organisms are indicators of dynamic soil quality because their community structure and population density are sensitive to management changes. However, edaphic properties can also affect soil organisms and high spatial variability can confound their utility for soil evaluation. In the present...

  19. Drainage and leaching dynamics in a cropped hummocky soil landscape with erosion-affected pedogenesis

    NASA Astrophysics Data System (ADS)

    Gerke, Horst H.; Rieckh, Helene; Sommer, Michael

    2016-04-01

    Hummocky soil landscapes are characterized by 3D spatial patterns of soil types that result from erosion-affected pedogenesis. Due to tillage and water erosion, truncated profiles have been formed at steep and mid slopes and colluvial soils at hollows. Pedogenetic variations in soil horizons at the different hillslope positions suggested feedback effects between erosion affected soil properties, the water balances, and the crop growth and leaching rates. Water balance simulations compared uniform with hillslope position-specific crop and root growths for soils at plateau, flat mid slope, steep slope, and hollow using the Hydrus-1D program. The boundary condition data were monitored at the CarboZALF-D experimental field site, which was cropped with perennial lucerne (Medicago sativa L.) in 2013 and 2014. Crop and root growth was assumed proportional to observed leaf area index (LAI). Fluxes of dissolved organic and inorganic carbon (DOC, DIC) were obtained from simulated water fluxes and measured DOC and DIC concentrations. For the colluvic soil, the predominately upward flow led to a net input in DIC and DOC. For the truncated soils at steep slopes, a reduced crop growth caused an relative increase in drainage, suggesting an accelerated leaching, which in the long term could accelerate the soil development and more soil variations along eroding hillslopes in arable soil landscapes.

  20. Effect of different soil washing solutions on bioavailability of residual arsenic in soils and soil properties.

    PubMed

    Im, Jinwoo; Yang, Kyung; Jho, Eun Hea; Nam, Kyoungphile

    2015-11-01

    The effect of soil washing used for arsenic (As)-contaminated soil remediation on soil properties and bioavailability of residual As in soil is receiving increasing attention due to increasing interest in conserving soil qualities after remediation. This study investigates the effect of different washing solutions on bioavailability of residual As in soils and soil properties after soil washing. Regardless of washing solutions, the sequential extraction revealed that the residual As concentrations and the amount of readily labile As in soils were reduced after soil washing. However, the bioassay tests showed that the washed soils exhibited ecotoxicological effects - lower seed germination, shoot growth, and enzyme activities - and this could largely be attributed to the acidic pH and/or excessive nutrient contents of the washed soils depending on washing solutions. Overall, this study showed that treated soils having lower levels of contaminants could still exhibit toxic effects due to changes in soil properties, which highly depended on washing solutions. This study also emphasizes that data on the As concentrations, the soil properties, and the ecotoxicological effects are necessary to properly manage the washed soils for reuses. The results of this study can, thus, be utilized to select proper post-treatment techniques for the washed soils. PMID:26086811

  1. Field-scale soil property changes under switchgrass managed for bioenergy

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The capacity of perennial grasses to affect change in soil properties is well documented but soil property information on switchgrass (Panicum virgatum L.) managed for bioenergy is limited. Potential improvements in near-surface soil function are important should switchgrass be included as a perenn...

  2. Natural attenuation of zinc pollution in smelter-affected soil.

    PubMed

    Vespa, M; Lanson, M; Manceau, A

    2010-10-15

    Previous synchrotron X-ray microprobe measurements of Zn speciation in contaminated and uncontaminated soils have identified phyllosilicate as the main sequestration phase. The emphasis now is focused on comparing the nature and properties of neoformed and geogenic phyllosilicate species to understand natural attenuation processes. Refined structural characterization of the two types of Zn-containing phyllosilicate in slightly basic smelter-affected agricultural soils were obtained using a so far unprecedented combination of X-ray microscopic techniques, including fluorescence (μ-XRF), absorption (μ-EXAFS), and diffraction (μ-XRD), and X-ray bulk-sensitive techniques, including powder and polarized EXAFS spectroscopy. The unpolluted and polluted species are both dioctahedral smectites, but the first which contains minor Zn (ca. 150 mg/kg) is aluminous and Fe-free, and the second, which contains several hundreds to a few thousands mg/kg Zn depending on the distance to the smelter and wind direction, is ferruginous with an average Fe/Al atomic ratio of 1.1 ± 0.5. The Zn(2+) and Fe(3+) in the neoformed smectite are derived from the weathering of ZnS, ZnO, FeS(2), and ZnFe(2)O(4) particles from the smelter. These cations diffuse away from their particulate mineral sources and coprecipitate with Al and Si in the soil clay matrix. Zinc sequestration in the octahedral sheet of dioctahedral smectite is potentially irreversible, because this type of phyllosilicate is stable over a large pH range, and the neoformed species is analogous to the native species which formed over time during pedogenesis. PMID:20853827

  3. Lunar soil properties and soil mechanics

    NASA Technical Reports Server (NTRS)

    Mitchell, J. K.; Houston, W. N.

    1974-01-01

    The long-range objectives were to develop methods of experimentation and analysis for the determination of the physical properties and engineering behavior of lunar surface materials under in situ environmental conditions. Data for this purpose were obtained from on-site manned investigations, orbiting and softlanded spacecraft, and terrestrial simulation studies. Knowledge of lunar surface material properties are reported for the development of models for several types of lunar studies and for the investigation of lunar processes. The results have direct engineering application for manned missions to the moon.

  4. The sorption of organic matter in soils as affected by the nature of soil carbon

    SciTech Connect

    Kaiser, K.; Haumaier, L.; Zech, W.

    2000-04-01

    Recent studies have shown that soil organic carbon (OC) may either hinder or favor the sorption of dissolved organic matter (DOM) in soils. The concept was that the nature of soil OC determines these contrasting findings. To test this hypothesis, the authors compared the DOM sorption in soils with OC derived from biomass decomposition with that in soils with OC more likely derived from biomass decomposition with that in soils with OC more likely derived from charred materials (black carbon). All the mineral soil samples in the study were from Spodosols, and the DOM was from an aqueous extract of a more forest floor layer. Sorption was determined in batch experiments. The sorption in soils that contain large amounts of black carbon was, in general, less than the sorption in soils with decomposition-derived OC. When the DOM sorption parameters of the soils were correlated to the OC content, the black carbon soils showed a positive effect of the OC content on the DOM sorption. In the soils lacking the features of black carbon residues, the DOM sorption was negatively influenced by OC. These results lead them to assume that the nature of soil OC is a soil property that needs to be considered in the DOM sorption of soils, especially when soils have large amounts of highly aromatic OC.

  5. Monitoring of soil water storage along elevation transech on morphological diverse study-sites affected by soil erosion

    NASA Astrophysics Data System (ADS)

    Jaksik, Ondrej; Kodesova, Radka; Nikodem, Antonin; Fer, Miroslav; Klement, Ales; Kratina, Josef

    2015-04-01

    Soil water availability is one of the key factors determining plant growth. Spatial distribution of soil water content is influenced by many factors. For the field-scale, one of the most important factors is terrain and its shape. The goal of our study was to characterize soil water storage within the soil profile with respect to terrain attributes. Two morphologically diverse study sites were chosen, in order to monitor soil water storage during vegetation season. The first site Brumovice in located in the Southern Moravian Region. The original soil unit was Haplic Chernozem developed on loess, which was gradually degraded by soil erosion. In the steepest parts, due to substantial loss of soil material, soil is transformed to Regosol. As a result of consequently sedimentation of previously eroded material in toe slopes and terrain depressions colluvial soils are formed. The second site Vidim is placed in the Central Bohemia. Dominant soil unit in wider area is Haplic Luvisol on loess loam. Similar process of progressive soil transformation was identified. On each study site, two elevation transects were delimited, where each consists of 5 monitoring spots. Access tubes were installed in order to measure soil moisture in six different depths (10, 20, 30 40, 60 a 100 cm) using Profile Probe PR2. The monitoring was conducted during vegetation season: April - July 2012 in Brumovice and May - July 2013 in Vidim. The average soil water contents were calculated for following three layers: topsoil A (0-20 cm), subsoil B (20-40cm), and substrate (40-100cm). The soil water storage within the soil profile was also expressed. Sensors TMS3 were also used for continual soil water content monitoring in the depth of 0-15 cm. In addition undisturbed soil samples were taken from topsoil to measure soil hydraulic properties using the multistep outflow experiment. Data were used to assess retention ability of erosion affected soils. The soil water storage and particularly average

  6. Tillage Effects on Soil Properties & Respiration

    NASA Astrophysics Data System (ADS)

    Rusu, Teodor; Bogdan, Ileana; Moraru, Paula; Pop, Adrian; Duda, Bogdan; Cacovean, Horea; Coste, Camelia

    2015-04-01

    Soil tillage systems can be able to influence soil compaction, water dynamics, soil temperature and soil structural condition. These processes can be expressed as changes of soil microbiological activity, soil respiration and sustainability of agriculture. Objectives of this study were: 1) to assess the effects of tillage systems (Conventional System-CS, Minimum Tillage-MT, No-Tillage-NT) on soil compaction, soil temperature, soil moisture and soil respiration and 2) to establish the relationship that exists in changing soil properties. Three treatments were installed: CS-plough + disc; MT-paraplow + rotary grape; NT-direct sowing. The study was conducted on an Argic-Stagnic Faeoziom. The MT and NT applications reduce or completely eliminate the soil mobilization, due to this, soil is compacted in the first year of application. The degree of compaction is directly related to soil type and its state of degradation. The state of soil compaction diminished over time, tending toward a specific type of soil density. Soil moisture was higher in NT and MT at the time of sowing and in the early stages of vegetation and differences diminished over time. Moisture determinations showed statistically significant differences. The MT and NT applications reduced the thermal amplitude in the first 15 cm of soil depth and increased the soil temperature by 0.5-2.20C. The determinations confirm the effect of soil tillage system on soil respiration; the daily average was lower at NT (315-1914 mmoli m-2s-1) and followed by MT (318-2395 mmoli m-2s-1) and is higher in the CS (321-2480 mmol m-2s-1). Comparing with CS, all the two conservation tillage measures decreased soil respiration, with the best effects of no-tillage. An exceeding amount of CO2 produced in the soil and released into the atmosphere, resulting from aerobic processes of mineralization of organic matter (excessive loosening) is considered to be not only a way of increasing the CO2 in the atmosphere, but also a loss of

  7. Soil type affects Pinus ponderosa var. scopulorum (Pinaceae) seedling growth in simulated drought experiments1

    PubMed Central

    Lindsey, Alexander J.; Kilgore, Jason S.

    2013-01-01

    • Premise of the study: Effects of drought stress and media type interactions on growth of Pinus ponderosa var. scopulorum germinants were investigated. • Methods and Results: Soil properties and growth responses under drought were compared across four growth media types: two native soils (dolomitic limestone and granite), a soil-less industry standard conifer medium, and a custom-mixed conifer medium. After 35 d of growth, the seedlings under drought stress (reduced watering) produced less shoot and root biomass than watered control seedlings. Organic media led to decreased root biomass, but increased root length and shoot biomass relative to the mineral soils. • Conclusions: Media type affected root-to-shoot biomass partitioning of P. ponderosa var. scopulorum, which may influence net photosynthetic rates, growth, and long-term seedling survival. Further work should examine how specific soil properties like bulk density and organic matter influence biomass allocation in greenhouse studies. PMID:25202578

  8. Effects of irrigation with treated wastewater on chemical soil properties

    NASA Astrophysics Data System (ADS)

    Parvan, M.; Danesh, S.; Alizadeh, A.

    2009-04-01

    The use of treated wastewater, as a marginal quality water, in agriculture is a justified practice, yet care should be taken to minimize adverse environmental impacts and to prevent soil deterioration. The objective of this research was to investigate the long-term effects of irrigation with treated wastewater on soil properties. The investigation was carried out by comparison of soil properties in two different fields; one irrigated with the effluent from Parkand Abad Wastewater Treatment Plant over a period of six years and the other one irrigated with water over the same period of time. Soil samples were taken from different depths of 0-25, 25-50, 50-100, 100-150 and 150-200 cm in both fields, and analyzed for various chemical properties. The results indicated that EC, TDS and Chlorine were increased significantly, in all depths, in the soil irrigated with the treated wastewater. The use of treated wastewater increased exchangeable potassium, magnesium and phosphorous significantly in the top soil layer (0-25), while the increase in calcium was occurred up to depth of 50 cm. Irrigation with the treated wastewater increased soil sodium content in all depths except for the depth of 100-150 cm. Irrigation with the treated wastewater did not affect the soil pH and nitrogen content significantly.

  9. Ecotoxicity of pentachlorophenol in contaminated soil as affected by soil type.

    PubMed

    Banks, M K; Schwab, A P

    2006-01-01

    Four uncontaminated soils were chosen with a wide range of pH, organic carbon, and clay content to allow us to determine the properties that were most influential on pentachlorophenol (PCP) toxicity. The soils were contaminated in the laboratory at concentrations of 50 and 100 mg/kg and target organisms were exposed to the contaminated soil. Germination and emergence of lettuce seedlings was found to be dependent upon PCP concentration and soil type, and responses were highly correlated to extractable concentrations. Earthworms were sensitive to PCP, regardless of soil properties, and mortality was observed in most samples at the 100 mg/kg concentration. Toxic responses by the worms were not strongly related to soil properties or extractable concentrations. The importance of soil chemical and physical properties on toxicity and bioavailability depends upon the target organism. In the case of lettuce seedlings, PCP is acquired through the aqueous phase; therefore, the chemical interaction between PCP and soil controls toxicity. Since earthworms ingest soil and potentially can change the chemical environment of exposure, the impact of soil properties on PCP toxicity is less apparent. PMID:16423718

  10. A harmonized vocabulary for soil observed properties

    NASA Astrophysics Data System (ADS)

    Simons, Bruce; Wilson, Peter; Cox, Simon; Vleeshouer, Jamie

    2014-05-01

    Interoperability of soil data depends on agreements concerning models, schemas and vocabularies. However, observed property terms are often defined during different activities and projects in isolation of one another, resulting in data that has the same scope being represented with different terms, using different formats and formalisms, and published in various access methods. Significantly, many soil property vocabularies conflate multiple concepts in a single term, e.g. quantity kind, units of measure, substance being observed, and procedure. Effectively, this bundles separate information elements into a single slot. We have developed a vocabulary for observed soil properties by adopting and extending a previously defined water quality vocabulary. The observed property model separates the information elements, based on the Open Geospatial Consortium (OGC) Observations & Measurements model and extending the NASA/TopQuadrant 'Quantities, Units, Dimensions and Types' (QUDT) ontology. The imported water quality vocabulary is formalized using the Web Ontology Language (OWL). Key elements are defined as sub-classes or sub-properties of standard Simple Knowledge Organization System (SKOS) elements, allowing use of standard vocabulary interfaces. For the soil observed property vocabulary, terms from QUDT and water quality are used where possible. These are supplemented with additional unit of measure (Unit), observed property (ScaledQuantityKind) and substance being observed (SubstanceOrTaxon) vocabulary entries required for the soil properties. The vocabulary terms have been extracted from the Australian Soil and Land Survey Field Handbook and Australian Soil Information Transfer and Evaluation System (SITES) vocabularies. The vocabulary links any chemical substances to items from the Chemical Entities of Biological Interest (ChEBI) ontology. By formalizing the model for observable properties, and clearly labelling the separate elements, soil property observations may

  11. BOREAS HYD-1 Soil Hydraulic Properties

    NASA Technical Reports Server (NTRS)

    Hall, Forrest G. (Editor); Knapp, David E. (Editor); Kelly, Shaun F.; Stangel, David E.; Smith, David E. (Technical Monitor)

    2000-01-01

    The Boreal Ecosystem-Atmosphere Study (BOREAS) Hydrology (HYD)-1 team coordinated a program of data collection to measure and monitor soil properties in collaboration with other science team measurement needs. This data set contains soil hydraulic properties determined at the Northern Study Area (NSA) and Southern Study Area (SSA) flux tower sites based on analysis of in situ tension infiltrometer tests and laboratory-determined water retention from soil cores collected during the 1994-95 field campaigns. Results from this analysis are saturated hydraulic conductivity, and fitting parameters for the van Genuchten-Mualem soil hydraulic conductivity and water retention function at flux tower sites. The data are contained in tabular ASCII files. The HYD-01 soil hydraulic properties data are available from the Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The data files are available on a CD-ROM (see document number 20010000884).

  12. Mapping specific soil functions based on digital soil property maps

    NASA Astrophysics Data System (ADS)

    Pásztor, László; Fodor, Nándor; Farkas-Iványi, Kinga; Szabó, József; Bakacsi, Zsófia; Koós, Sándor

    2016-04-01

    Quantification of soil functions and services is a great challenge in itself even if the spatial relevance is supposed to be identified and regionalized. Proxies and indicators are widely used in ecosystem service mapping. Soil services could also be approximated by elementary soil features. One solution is the association of soil types with services as basic principle. Soil property maps however provide quantified spatial information, which could be utilized more versatilely for the spatial inference of soil functions and services. In the frame of the activities referred as "Digital, Optimized, Soil Related Maps and Information in Hungary" (DOSoReMI.hu) numerous soil property maps have been compiled so far with proper DSM techniques partly according to GSM.net specifications, partly by slightly or more strictly changing some of its predefined parameters (depth intervals, pixel size, property etc.). The elaborated maps have been further utilized, since even DOSoReMI.hu was intended to take steps toward the regionalization of higher level soil information (secondary properties, functions, services). In the meantime the recently started AGRAGIS project requested spatial soil related information in order to estimate agri-environmental related impacts of climate change and support the associated vulnerability assessment. One of the most vulnerable services of soils in the context of climate change is their provisioning service. In our work it was approximated by productivity, which was estimated by a sequential scenario based crop modelling. It took into consideration long term (50 years) time series of both measured and predicted climatic parameters as well as accounted for the potential differences in agricultural practice and crop production. The flexible parametrization and multiple results of modelling was then applied for the spatial assessment of sensitivity, vulnerability, exposure and adaptive capacity of soils in the context of the forecasted changes in

  13. Inferences about radionuclide mobility in soils based on the solid/liquid partition coefficients and soil properties.

    PubMed

    Sohlenius, Gustav; Saetre, Peter; Nordén, Sara; Grolander, Sara; Sheppard, Steve

    2013-05-01

    To assist transport modeling in assessments of the radiological impact of a geological repository for radioactive wastes, the mobility of various elements was studied in arable and wetland soils in the Forsmark region, Sweden. Pore water and total element contents were determined for five types of unconsolidated deposits (regolith), spanning a wide range of soil properties with respect to pH and organic matter content. Two soil depths were sampled to capture element mobility in regolith layers affected and unaffected by soil-forming processes. The solid/liquid partition coefficients (K d values) for most elements varied significantly among regolith types. For most elements, the observed variations in K d values could be explained by variations in soil properties. For many elements, mobility increased with decreasing soil pH. The results provide a significant addition of data on radionuclide retention in soils, taking account of soil properties and processes. PMID:23619799

  14. Genetic by environment interactions affect plant–soil linkages

    PubMed Central

    Pregitzer, Clara C; Bailey, Joseph K; Schweitzer, Jennifer A

    2013-01-01

    The role of plant intraspecific variation in plant–soil linkages is poorly understood, especially in the context of natural environmental variation, but has important implications in evolutionary ecology. We utilized three 18- to 21-year-old common gardens across an elevational gradient, planted with replicates of five Populus angustifolia genotypes each, to address the hypothesis that tree genotype (G), environment (E), and G × E interactions would affect soil carbon and nitrogen dynamics beneath individual trees. We found that soil nitrogen and carbon varied by over 50% and 62%, respectively, across all common garden environments. We found that plant leaf litter (but not root) traits vary by genotype and environment while soil nutrient pools demonstrated genotype, environment, and sometimes G × E interactions, while process rates (net N mineralization and net nitrification) demonstrated G × E interactions. Plasticity in tree growth and litter chemistry was significantly related to the variation in soil nutrient pools and processes across environments, reflecting tight plant–soil linkages. These data overall suggest that plant genetic variation can have differential affects on carbon storage and nitrogen cycling, with implications for understanding the role of genetic variation in plant–soil feedback as well as management plans for conservation and restoration of forest habitats with a changing climate. PMID:23919173

  15. Psychometric properties of the Affect Phobia Test.

    PubMed

    Frankl, My; Philips, Björn; Berggraf, Lene; Ulvenes, Pål; Johansson, Robert; Wennberg, Peter

    2016-10-01

    The aim of this study was to make the first evaluation of the psychometric properties of the Affect Phobia Test, using the Swedish translation - a test developed to screen the ability to experience, express and regulate emotions. Data was collected from a clinical sample (N = 82) of patients with depression and/or anxiety participating in randomized controlled trial of Internet-based affect-focused treatment, and a university student sample (N = 197). The internal consistency for the total score was satisfactory (Clinical sample α = 0.88/Student sample α = 0.84) as well as for all the affective domains, except Anger/Assertion (α = 0.44/0.36), Sadness/Grief (α = 0.24/0.46) and Attachment/Closeness (α = 0.67/0.69). Test retest reliability was satisfactory (ICC > 0.77) for the total score and for all the affective domains except for Sadness/Grief (ICC = 0.04). The exploratory factor analysis resulted in a six-factor solution and did only moderately match the test's original affective domains. An empirical cut-off between the clinical and the university student sample were calculated and yielded a cut-off of 72 points. As expected, the Affect Phobia test showed negative significant correlations in the clinical group with measures on depression (rxy  = -0.229; p < 0.01) and anxiety (rxy  = -0.315; p < 0.05). The conclusion is that the psychometric properties are satisfactory for the total score of the Affect Phobia Test but not for some of the test's affective domains. Consequently the domains should not be used as subscales. The test can discriminate between individuals who seek help for psychological problems and those who do not. PMID:27461917

  16. Ice nucleation properties of agricultural soil dusts

    NASA Astrophysics Data System (ADS)

    Steinke, Isabelle; Funk, Roger; Busse, Jacqueline; Iturri, Antonela; Kirchen, Silke; Leue, Martin; Möhler, Ottmar; Schwartz, Thomas; Sierau, Berko; Toprak, Emre; Ulrich, Andreas; Hoose, Corinna; Leisner, Thomas

    2015-04-01

    Soil dust particles emitted from agricultural areas contain large amounts of organic material such as fungi, bacteria and plant debris. Being carrier for potentially highly ice-active biological particles, agricultural soil dusts are candidates for being very ice-active as well. In this work, we present ice nucleation experiments conducted in the AIDA cloud chamber. We investigated the ice nucleation efficiency of four types of soil dust from different regions of the world. Results are presented for the immersion freezing and the deposition nucleation mode: all soil dusts show higher ice nucleation efficiencies than desert dusts, especially at temperatures above 254 K. For one soil dust sample, the effect of heat treatments was investigated. Heat treatments did not affect the ice nucleation efficiency which presumably excludes primary biological particles as the only source of the increased ice nucleation efficiency. Therefore, organo-mineral complexes or organic compounds may contribute substantially to the high ice nucleation activity of agricultural soil dusts.

  17. Pharmaceuticals' sorptions relative to properties of thirteen different soils.

    PubMed

    Kodešová, Radka; Grabic, Roman; Kočárek, Martin; Klement, Aleš; Golovko, Oksana; Fér, Miroslav; Nikodem, Antonín; Jakšík, Ondřej

    2015-04-01

    Transport of human and veterinary pharmaceuticals in soils and consequent ground-water contamination are influenced by many factors, including compound sorption on soil particles. Here we evaluate the sorption isotherms for 7 pharmaceuticals on 13 soils, described by Freundlich equations, and assess the impact of soil properties on various pharmaceuticals' sorption on soils. Sorption of ionizable pharmaceuticals was, in many cases, highly affected by soil pH. The sorption coefficient of sulfamethoxazole was negatively correlated to soil pH, and thus positively related to hydrolytic acidity and exchangeable acidity. Sorption coefficients for clindamycin and clarithromycin were positively related to soil pH and thus negatively related to hydrolytic acidity and exchangeable acidity, and positively related to base cation saturation. The sorption coefficients for the remaining pharmaceuticals (trimethoprim, metoprolol, atenolol, and carbamazepine) were also positively correlated with the base cation saturation and cation exchange capacity. Positive correlations between sorption coefficients and clay content were found for clindamycin, clarithromycin, atenolol, and metoprolol. Positive correlations between sorption coefficients and organic carbon content were obtained for trimethoprim and carbamazepine. Pedotransfer rules for predicting sorption coefficients of various pharmaceuticals included hydrolytic acidity (sulfamethoxazole), organic carbon content (trimethoprimand carbamazepine), base cation saturation (atenolol and metoprolol), exchangeable acidity and clay content (clindamycin), and soil active pH and clay content (clarithromycin). Pedotransfer rules, predicting the Freundlich sorption coefficients, could be applied for prediction of pharmaceutical mobility in soils with similar soil properties. Predicted sorption coefficients together with pharmaceutical half-lives and other imputes (e.g., soil-hydraulic, geological, hydro-geological, climatic) may be used for

  18. Sorption of roxarsone onto soils with different physicochemical properties.

    PubMed

    Fu, Qing-Long; He, Jian-Zhou; Blaney, Lee; Zhou, Dong-Mei

    2016-09-01

    Elevated roxarsone (ROX) concentrations in soils, caused by land application of ROX-bearing poultry litter, mandate investigation of ROX sorption onto soils. Equilibrium and kinetic studies of ROX sorption onto five soils were carried out to explore the relationship between sorption parameters and soil properties, and to reveal the effects of coexisting humic acid (HA), P(V), As(V), and As(III) on ROX transport. Experimental results indicated that ROX sorption reached equilibrium within 24 h, with pseudo-second order rate constants of 5.74-5.26 × 10(2) g/(mg h); film and intra-particle diffusion were the rate-limiting processes. ROX sorption to soils involved partitioning and adsorption phenomena; however, their relative contributions varied for different soils. The maximum ROX sorption varied with soil type, ranging from 0.59 to 4.12 mg/g. Results from correlation analysis and multiple linear regressions revealed that the maximum sorption capacities, partition coefficients, and desorption percentages were correlated with soil properties, especially iron content, total organic carbon, and dissolved organic carbon. ROX sorption to soils was affected more by soil pH than the initial pH of ROX-containing solutions. Carboxylic and amide functional groups were determined to be responsible for ROX sorption to soils. ROX sorption capacities decreased in the presence of HA, P(V), As(V), and As(III), indicating that ROX mobility in soils was facilitated by dissolved organic matter (DOM) and competing anions. PMID:27281543

  19. Biophysical Properties as Determinants for Soil Organic Carbon and Total Nitrogen in Grassland Salinization

    PubMed Central

    Pan, Chengchen; Zhao, Halin; Zhao, Xueyong; Han, Huibang; Wang, Yan; Li, Jin

    2013-01-01

    Grassland salinization causes considerable changes to soil and vegetation, which can lead to changes in soil organic carbon (C) and total nitrogen (N). These changes have complex causal relationships. A significant correlation between soil organic C and total N and any soil or vegetation property does not necessarily imply a significant direct effect of the property on soil organic C and total N. In this study, a field survey was conducted to investigate the changes in soil organic C and total N in grassland along a salinity gradient in Hexi corridor, China, and the direct and indirect effects of soil and vegetation properties on both stocks were quantified using a path analysis approach. Significant decrease in soil organic C and total N contents were observed with increasing salinity. Both had significant positive correlations with the Normalized Difference Vegetation Index (NDVI), soil water, and fine particles (silt+clay) content (p<0.01) and significant negative correlations with soil EC, and sand content (p<0.01). NDVI, fine particles content and soil water content had positive direct effects on soil organic C and total N stocks. Soil EC affected soil organic C and total N stocks mainly through its indirect negative effect on NDVI, soil texture, and water content. NDVI, soil texture, and moisture also indirectly affected soil organic C and total N stocks via changes in each other. These indirect effects augmented each other, although in some cases indirect effects worked in opposing directions. PMID:23372776

  20. Estimating soil moisture and soil thermal and hydraulic properties by assimilating soil temperatures using a particle batch smoother

    NASA Astrophysics Data System (ADS)

    Dong, Jianzhi; Steele-Dunne, Susan C.; Ochsner, Tyson E.; Giesen, Nick van de

    2016-05-01

    This study investigates the potential of estimating the soil moisture profile and the soil thermal and hydraulic properties by assimilating soil temperature at shallow depths using a particle batch smoother (PBS) using synthetic tests. Soil hydraulic properties influence the redistribution of soil moisture within the soil profile. Soil moisture, in turn, influences the soil thermal properties and surface energy balance through evaporation, and hence the soil heat transfer. Synthetic experiments were used to test the hypothesis that assimilating soil temperature observations could lead to improved estimates of soil hydraulic properties. We also compared different data assimilation strategies to investigate the added value of jointly estimating soil thermal and hydraulic properties in soil moisture profile estimation. Results show that both soil thermal and hydraulic properties can be estimated using shallow soil temperatures. Jointly updating soil hydraulic properties and soil states yields robust and accurate soil moisture estimates. Further improvement is observed when soil thermal properties were also estimated together with the soil hydraulic properties and soil states. Finally, we show that the inclusion of a tuning factor to prevent rapid fluctuations of parameter estimation, yields improved soil moisture, temperature, and thermal and hydraulic properties.

  1. Impact of soil properties on selected pharmaceuticals adsorption in soils

    NASA Astrophysics Data System (ADS)

    Kodesova, Radka; Kocarek, Martin; Klement, Ales; Fer, Miroslav; Golovko, Oksana; Grabic, Roman; Jaksik, Ondrej

    2014-05-01

    The presence of human and veterinary pharmaceuticals in the environment has been recognized as a potential threat. Pharmaceuticals may contaminate soils and consequently surface and groundwater. Study was therefore focused on the evaluation of selected pharmaceuticals adsorption in soils, as one of the parameters, which are necessary to know when assessing contaminant transport in soils. The goals of this study were: (1) to select representative soils of the Czech Republic and to measure soil physical and chemical properties; (2) to measure adsorption isotherms of selected pharmaceuticals; (3) to evaluate impact of soil properties on pharmaceutical adsorptions and to propose pedotransfer rules for estimating adsorption coefficients from the measured soil properties. Batch sorption tests were performed for 6 selected pharmaceuticals (beta blockers Atenolol and Metoprolol, anticonvulsant Carbamazepin, and antibiotics Clarithromycin, Trimetoprim and Sulfamethoxazol) and 13 representative soils (soil samples from surface horizons of 11 different soil types and 2 substrates). The Freundlich equations were used to describe adsorption isotherms. The simple correlations between measured physical and chemical soil properties (soil particle density, soil texture, oxidable organic carbon content, CaCO3 content, pH_H2O, pH_KCl, exchangeable acidity, cation exchange capacity, hydrolytic acidity, basic cation saturation, sorption complex saturation, salinity), and the Freundlich adsorption coefficients were assessed using Pearson correlation coefficient. Then multiple-linear regressions were applied to predict the Freundlich adsorption coefficients from measured soil properties. The largest adsorption was measured for Clarithromycin (average value of 227.1) and decreased as follows: Trimetoprim (22.5), Metoprolol (9.0), Atenolol (6.6), Carbamazepin (2.7), Sulfamethoxazol (1.9). Absorption coefficients for Atenolol and Metoprolol closely correlated (R=0.85), and both were also

  2. Volatilization of EPTC as affected by soil moisture

    NASA Astrophysics Data System (ADS)

    Fu, Liqun

    Volatilization is an important process that controls the dissipation of pesticides after field application. Soil moisture plays an important role in controlling the volatilization of pesticides. However, the extent of this role is unclear. This study was conducted to determine how soil moisture affects the sorption capacity and vapor loss of EPTC (S-ethyl dipropyl carbamothioate) from two soils, Weswood clay loam (fine- silty, mixed, thermic fluventic ustochrepts) and Padina loamy sand (loamy, siliceous, thermic grossarenic paleustalfs). Soil samples with different moisture contents were exposed to saturated EPTC vapor for 1, 2, 5, or 12 days and sorbed concentrations were measured. Sorption capacity of Weswood after 12 days exposure was about 12 times higher with air-dry soil than at the wilting point (-1500 kPa). For Padina, after 12 days exposure, the sorption capacity was about 18 times higher at air- dry than at -1500 kPa. The maximum sorption extrapolated from the partitioning coefficients determined with an equilibrium batch system and Henry's law were similar to the sorption capacities when moisture content was close to the wilting point for both soils. Desorption of EPTC vapor from soils with different moistures was determined by a purge and trap method. EPTC vapor losses strongly depended on the soil moisture and/or the humidity of the air. If the air was dry, volatilization of EPTC was much larger when the soil was wet. If humidity of the air was high, the effect of soil moisture on volatilization was not as great. No significant correlation at a confidence level of 95% was found between water and EPTC vapor losses for either soil when water saturated air was used as a purge gas. When purged with dry air, losses of water and EPTC vapor were strongly correlated at a confidence level of 99%. This study indicates that decreasing soil moisture significantly increases EPTC sorption and decreases volatilization. Simulation of volatilization with a one

  3. Can subterranean cave systems affect soil CO2 fluxes?

    NASA Astrophysics Data System (ADS)

    Krajnc, Bor; Ferlan, Mitja; Ogrinc, Nives

    2015-04-01

    Main factors affecting soil CO2 fluxes in most ecosystems are soil temperature and soil moisture. Nevertheless occasionally high soil CO2 fluxes were observed at carst areas, which could result from ventilation of subterranean cavities (Ferlan et al., 2011). The aim of this work was to determine the influence of cave ventilation to soil CO2 fluxes. Research was done in a dead-end passage of Postojna cave (Pisani rov) and on the surface area above the passage (Velika Jeršanova dolina) in south-western Slovenia. Inside the cave we measured CO2 concentrations, its carbon (13C) stable isotope composition, 222Rn activity concentrations, temperatures and air pressure. At the surface we had chosen two sampling plots; test plot above the cave and control. At both plots we measured soil CO2 fluxes with automatic chambers, CO2 concentrations, temperatures and carbon stable isotope composition of soil air at three different depths (0.2 m, 0.5 m and 0.8 m) and different meteorological parameters such as: air temperature, air pressure, wind speed an precipitation. To detect the cave influence, we compared two surface CO2 flux measurements with air temperatures and changes of CO2 concentrations in the cave atmosphere. Our results on CO2 concentrations in the gallery of the cave indicated that the ventilation of this particular gallery also depends on outside air temperatures. Outside temperature increased and corresponded to higher CO2 concentrations, whereas at lower temperatures (T < 9 oC) cave started to ventilate and exhaled CO2 reach air through unknown fissures and cracks. At the control plot the soil CO2 fluxes were in a good correlation with soil temperatures (r = 0.789, p =0.01), where greater soil temperatures correspond to greater soil CO2 fluxes. Soil CO2 fluxes at the plot above the cave did not show statistically significant correlations with soil temperatures or soil moisture indicating that other factors possibly cave ventilation could influence it. References

  4. Effects of aggressive remediation on soil properties and function

    NASA Astrophysics Data System (ADS)

    Switzer, Christine; Zihms, Stephanie; Pape, Andrew; Robson, Andrew; Knapp, Charles

    2013-04-01

    Aggressive remediation processes such as thermal desorption, smouldering, and chemical oxidiation remediation processes have significant promise to deliver substantial contaminant reduction in short periods of time, effecting as much as 95-99+% mass removal from non-aqueous phase liquid (NAPL) source zones. In situ thermal remediation exposes soils to temperatures of 100+°C for periods of weeks or months. In situ smouldering exposes soils to 600-1000+°C for hours to days. Chemical oxidation exposes soils to harsh oxidizing chemicals for weeks or months effecting reactive degradation of chemical contaminants but also surrounding soils. These processes have the potential to result in significant changes to the soil properties, particularly at the particle surface and grain interfaces. The dynamic effects of these changes have important implications in soil management practice. The mobilisation of soil nutrients may challenge rehabilitation or biological "polishing" after aggressive remediation. Plant germination and growth are inhibited and water dynamics are affected as well. Although permeability remains unaffected, infiltration is more rapid and capillary rise is reduced after smouldering remediation. Mobilisation of fines does not explain the change in infiltration and capillary rise; these effects persist after removal of the smaller half of the particle size distribution. Some separation of the soil column is observed in water infiltration after both thermal and smouldering remediation, indicating that erosion and subsidence are potential problems. These effects may be manifestations of subcritical water repellency. Based on the retention of capillary rise and lack of effects on other soil properties, the soil should be amenable to improvement measures. This presentation will place the effects of aggressive remediation into context within real soils and model materials.

  5. Performance of demining sensors and soil properties

    NASA Astrophysics Data System (ADS)

    Takahashi, Kazunori; Preetz, Holger; Igel, Jan

    2011-06-01

    Metal detector has commonly been used for landmine detection and ground-penetrating radar (GPR) is about to be deployed as dual sensor that is in combination with metal detector. Since both devices employ electromagnetic techniques, they are influenced by magnetic and dielectric properties of soil. To observe the influence, various soil properties as well as their spatial distributions were measured in four types of soil where a field test of metal detectors and GPRs took place. By analyzing soil properties these four types of soil were graded based on the estimated amount of influence on the detection techniques. The classification was compared to the detection performance of devices obtained from the blind test and a clear correlation between the difficulty of soil and the performance was observed; the detection and identification performance were degraded in soils that were classified as problematic. Therefore, it was demonstrated that the performance of metal detector and GPR for landmine detection can qualitatively be assessed by geophysical analyses.

  6. Variability of magnetic soil properties in Hawaii

    NASA Astrophysics Data System (ADS)

    van Dam, Remke L.; Harrison, J. Bruce J.; Hendrickx, Jan M. H.; Borchers, Brian; North, Ryan E.; Simms, Janet E.; Jasper, Chris; Smith, Christopher W.; Li, Yaoguo

    2005-06-01

    Magnetic soils can seriously hamper the performance of electromagnetic sensors for the detection of buried land mines and unexploded ordnance (UXO). Soils formed on basaltic substrates commonly have large concentrations of ferrimagnetic iron oxide minerals, which are the main cause of soil magnetic behavior. Previous work has shown that viscous remanent magnetism (VRM) in particular, which is caused by the presence of ferrimagnetic minerals of different sizes and shapes, poses a large problem for electromagnetic surveys. The causes of the variability in magnetic soil properties in general and VRM in particular are not well understood. In this paper we present the results of laboratory studies of soil magnetic properties on three Hawaiian Islands: O"ahu, Kaho"olawe, and Hawaii. The data show a strong negative correlation between mean annual precipitation and induced magnetization, and a positive correlation between mean annual precipitation and the frequency dependent magnetic behavior. Soil erosion, which reduces the thickness of the soil cover, also influences the magnetic properties.

  7. Ranking factors affecting emissions of GHG from incubated agricultural soils.

    PubMed

    García-Marco, S; Ravella, S R; Chadwick, D; Vallejo, A; Gregory, A S; Cárdenas, L M

    2014-07-01

    Agriculture significantly contributes to global greenhouse gas (GHG) emissions and there is a need to develop effective mitigation strategies. The efficacy of methods to reduce GHG fluxes from agricultural soils can be affected by a range of interacting management and environmental factors. Uniquely, we used the Taguchi experimental design methodology to rank the relative importance of six factors known to affect the emission of GHG from soil: nitrate (NO3 (-)) addition, carbon quality (labile and non-labile C), soil temperature, water-filled pore space (WFPS) and extent of soil compaction. Grassland soil was incubated in jars where selected factors, considered at two or three amounts within the experimental range, were combined in an orthogonal array to determine the importance and interactions between factors with a L16 design, comprising 16 experimental units. Within this L16 design, 216 combinations of the full factorial experimental design were represented. Headspace nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) concentrations were measured and used to calculate fluxes. Results found for the relative influence of factors (WFPS and NO3 (-) addition were the main factors affecting N2O fluxes, whilst glucose, NO3 (-) and soil temperature were the main factors affecting CO2 and CH4 fluxes) were consistent with those already well documented. Interactions between factors were also studied and results showed that factors with little individual influence became more influential in combination. The proposed methodology offers new possibilities for GHG researchers to study interactions between influential factors and address the optimized sets of conditions to reduce GHG emissions in agro-ecosystems, while reducing the number of experimental units required compared with conventional experimental procedures that adjust one variable at a time. PMID:25177207

  8. Ranking factors affecting emissions of GHG from incubated agricultural soils

    PubMed Central

    García-Marco, S; Ravella, S R; Chadwick, D; Vallejo, A; Gregory, A S; Cárdenas, L M

    2014-01-01

    Agriculture significantly contributes to global greenhouse gas (GHG) emissions and there is a need to develop effective mitigation strategies. The efficacy of methods to reduce GHG fluxes from agricultural soils can be affected by a range of interacting management and environmental factors. Uniquely, we used the Taguchi experimental design methodology to rank the relative importance of six factors known to affect the emission of GHG from soil: nitrate (NO3−) addition, carbon quality (labile and non-labile C), soil temperature, water-filled pore space (WFPS) and extent of soil compaction. Grassland soil was incubated in jars where selected factors, considered at two or three amounts within the experimental range, were combined in an orthogonal array to determine the importance and interactions between factors with a L16 design, comprising 16 experimental units. Within this L16 design, 216 combinations of the full factorial experimental design were represented. Headspace nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) concentrations were measured and used to calculate fluxes. Results found for the relative influence of factors (WFPS and NO3− addition were the main factors affecting N2O fluxes, whilst glucose, NO3− and soil temperature were the main factors affecting CO2 and CH4 fluxes) were consistent with those already well documented. Interactions between factors were also studied and results showed that factors with little individual influence became more influential in combination. The proposed methodology offers new possibilities for GHG researchers to study interactions between influential factors and address the optimized sets of conditions to reduce GHG emissions in agro-ecosystems, while reducing the number of experimental units required compared with conventional experimental procedures that adjust one variable at a time. PMID:25177207

  9. Spatial and temporal variability of soil temperature, moisture and surface soil properties

    NASA Technical Reports Server (NTRS)

    Hajek, B. F.; Dane, J. H.

    1993-01-01

    The overall objectives of this research were to: (l) Relate in-situ measured soil-water content and temperature profiles to remotely sensed surface soil-water and temperature conditions; to model simultaneous heat and water movement for spatially and temporally changing soil conditions; (2) Determine the spatial and temporal variability of surface soil properties affecting emissivity, reflectance, and material and energy flux across the soil surface. This will include physical, chemical, and mineralogical characteristics of primary soil components and aggregate systems; and (3) Develop surface soil classes of naturally occurring and distributed soil property assemblages and group classes to be tested with respect to water content, emissivity and reflectivity. This document is a report of studies conducted during the period funded by NASA grants. The project was designed to be conducted over a five year period. Since funding was discontinued after three years, some of the research started was not completed. Additional publications are planned whenever funding can be obtained to finalize data analysis for both the arid and humid locations.

  10. Tillage Effects on Soil Hydraulic Properties in Space and Time: State of the Science

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil tillage practices can affect soil hydraulic properties and processes in space and time with consequent and coupled effects on chemical movement and plant growth. This literature review addresses the quantitative effects of soil tillage and associated management (e.g., crop residues) on the tem...

  11. Predicting Soil Biological and Physical Properties Using Hydrological Properties

    NASA Astrophysics Data System (ADS)

    Geiger, L.; Hofmockel, K.; Kaleita, A.; Hargreaves, S.

    2012-12-01

    Soil biological and chemical properties vary at different spatial scales, which make predicting processes associated with these properties difficult. However, soil biological and chemical properties are important to fertility and ecosystem functioning. In this study, we used a Self Organizing Map (SOM) to determine whether soil hydrological characteristics can be used to characterize the distribution of a suite of soil biological and chemical properties. From a row crop field in south-central Iowa, we generated 36 sampling locations via a SOM, which were grouped into three categories according to hydrological properties by the SOM. Soil samples were then analyzed for microbial biomass, carbon and nitrogen mineralization potential, and organic and inorganic pools of carbon and nitrogen. We found that sampling locations in category 1 (potholes and toe slopes) had greater microbial biomass, total carbon, total nitrogen, and extractable organic carbon than compared locations in the two well-drained categories. Nitrogen and carbon mineralization and inorganic nitrogen pools did not differ significantly among the categories. These results demonstrate that hydrological characteristics can be used to predict relatively stable biological and chemical soil properties. However, prediction of nitrogen and carbon fluxes remains a challenge.

  12. Microbial response following straw application in a soil affected by a wildfire

    NASA Astrophysics Data System (ADS)

    Barreiro, Ana; Lombao, Alba; Díaz-Raviña, Montserrat; Martin, Angela; Fontúrbel, Maria Teresa; Vega, Jose Antonio; Fernández, Cristina; Carballas, Tarsy

    2015-04-01

    Mulching treatment is often recommended to reduce post-fire erosion and sediments yields but information concerning their effects on soil microorganisms is scarce. In the present investigation the evolution of several parameters related with the mass and activity of soil microorganisms was examined in a hillslope shrubland located in Saviñao (Lugo, NW Spain) and susceptible to suffer post-fire erosion (38% slope). In this area, affected by a medium-high severity wildfire in September 2012, different treatments with wheat straw applied to the burnt soil in mulch strips (800 and 1000 kg ha-1) were established by quadruplicate (10 m x 40 m plots) and compared with the corresponding burnt untreated control. Soil samples were collected from the A horizon (0-2.5 cm depth) at different sampling times over one year after the wildfire and different soil biochemical properties (microbial biomass C, soil respiration, bacterial activity, -glucosidase, urease and phosphatase activities) were analyzed. The results showed large variation among the four field replicates of the same treatment (spatial variability), which makes difficult to evaluate the effect of mulch treatment. The evolution of the different biochemical properties in the post-fire stabilization treatments with the wheat straw applied in mulch strips were mainly related to the time passed after the fire (short- and medium- term changes in soil physical and chemical properties induced by both fire and climatic conditions) rather than to the straw mulching effects; in addition, a different temporal pattern was observed depending on the variable considered. The results pointed out the usefulness of examining intra-annual natural variability (spatial variation, seasonal fluctuations) when different indices of mass and activity of microorganisms were used as monitoring tools in soil ecosystems affected by fire. Acknowledgements. A. Barreiro and A. Lombao are recipients of FPU grants from Spanish Ministry of

  13. Permafrost-Affected Soils of the Russian Arctic and their Carbon Pools

    NASA Astrophysics Data System (ADS)

    Zubrzycki, S.; Kutzbach, L.; Pfeiffer, E.-M.

    2014-02-01

    Permafrost-affected soils have accumulated enormous pools of organic matter during the Quaternary Period. The area occupied by these soils amounts to more than 8.6 million km2, which is about 27% of all land areas north of 50° N. Therefore, permafrost-affected soils are considered to be one of the most important cryosphere elements within the climate system. Due to the cryopedogenic processes that form these particular soils and the overlying vegetation that is adapted to the arctic climate, organic matter has accumulated to the present extent of up to 1024 Pg (1 Pg = 1015 g = 1 Gt) of soil organic carbon stored within the uppermost three meters of ground. Considering the observed progressive climate change and the projected polar amplification, permafrost-affected soils will undergo fundamental property changes. Higher turnover and mineralization rates of the organic matter are consequences of these changes, which are expected to result in an increased release of climate-relevant trace gases into the atmosphere. As a result, permafrost regions with their distinctive soils are likely to trigger an important tipping point within the global climate system, with additional political and social implications. The controversy of whether permafrost regions continue accumulating carbon or already function as a carbon source remains open until today. An increased focus on this subject matter, especially in underrepresented Siberian regions, could contribute to a more robust estimation of the soil organic carbon pool of permafrost regions and at the same time improve the understanding of the carbon sink and source functions of permafrost-affected soils.

  14. Effects of fire on properties of forest soils: a review.

    PubMed

    Certini, Giacomo

    2005-03-01

    Many physical, chemical, mineralogical, and biological soil properties can be affected by forest fires. The effects are chiefly a result of burn severity, which consists of peak temperatures and duration of the fire. Climate, vegetation, and topography of the burnt area control the resilience of the soil system; some fire-induced changes can even be permanent. Low to moderate severity fires, such as most of those prescribed in forest management, promote renovation of the dominant vegetation through elimination of undesired species and transient increase of pH and available nutrients. No irreversible ecosystem change occurs, but the enhancement of hydrophobicity can render the soil less able to soak up water and more prone to erosion. Severe fires, such as wildfires, generally have several negative effects on soil. They cause significant removal of organic matter, deterioration of both structure and porosity, considerable loss of nutrients through volatilisation, ash entrapment in smoke columns, leaching and erosion, and marked alteration of both quantity and specific composition of microbial and soil-dwelling invertebrate communities. However, despite common perceptions, if plants succeed in promptly recolonising the burnt area, the pre-fire level of most properties can be recovered and even enhanced. This work is a review of the up-to-date literature dealing with changes imposed by fires on properties of forest soils. Ecological implications of these changes are described. PMID:15688212

  15. Spatial characterization of soil properties and influence in soil formation in oak-grassland of Sierra Morena, S Spain

    NASA Astrophysics Data System (ADS)

    Román-Sánchez, Andrea; Cáceres, Francisco; Pédèches, Remi; Giráldez Cervera, Juan Vicente; Vanwalleghem, Tom

    2016-04-01

    The Mediterranean oak-grassland ecosystem is very important for the rural economy and for the biodiversity of south-western European countries like Spain and Portugal. Nevertheless these ecosystems are not well characterized especially their soils. In this report soil carbon has been evaluated and related to other properties. The principal factors controlling the structure, productivity and evolution of forest ecosystems are bedrock, climate, relief, vegetation and time. Soil carbon has an important influence in the soil and ecosystem structures. The purpose of this study is to determine the relationship between relief, soil properties, spatial distribution of soil carbon and their influence in soil formation and geomorphology. This work is part of another study which aims to elucidate the processes involved in the soil formation and to examine their behaviour on long-term with a modelling. In our study area, located in oak-grassland of Sierra Morena, in Cordoba, S Spain, have been studied 67 points at 6 depths in 262 hectares in order to determine carbon content varying between 0-6%, soil properties such as soil depth between 0-4 m, horizon depth and the rocks amount in surface. The relationship between the soil carbon, soil properties and the relief characteristic like slope, aspect, curvature can shed light the processes that affect the mechanisms of bedrock weathering and their interrelationship with geomorphological processes.

  16. Prolonged Soil Frost Affects Hydraulics and Phenology of Apple Trees.

    PubMed

    Beikircher, Barbara; Mittmann, Claudia; Mayr, Stefan

    2016-01-01

    Restoration of an adequate water supply in spring is a prerequisite for survival of angiosperm trees in temperate regions. Trees must re-establish access to soil water and recover xylem functionality. We thus hypothesized that prolonged soil frost impairs recovery and affects hydraulics and phenology of Malus domestica var. 'Golden Delicious.' To test this hypothesis, over two consecutive winters the soil around some trees was insulated to prolong soil frosting, From mid-winter to early summer, the level of native embolism, the water and starch contents of wood, bark and buds were quantified at regular intervals and findings correlated with various phenological parameters, xylogenesis and fine root growth. The findings confirm that prolonged soil frost affects tree hydraulics and phenology but the severity of the effect depends on the climatic conditions. In both study years, percentage loss of hydraulic conductivity (PLC) decreased from about 70% at the end of winter to about 10% in May. Thereby, xylem refilling strongly coincided with a decrease of starch in wood and bark. Also treated trees were able to restore their hydraulic system by May but, in the warm spring of 2012, xylem refilling, the increases in water content and starch depolymerization were delayed. In contrast, in the cold spring of 2013 only small differences between control and treated trees were observed. Prolongation of soil frost also led to a delay in phenology, xylogenesis, and fine root growth. We conclude that reduced water uptake from frozen or cold soils impairs refilling and thus negatively impacts tree hydraulics and growth of apple trees in spring. Under unfavorable circumstances, this may cause severe winter damage or even dieback. PMID:27379146

  17. Prolonged Soil Frost Affects Hydraulics and Phenology of Apple Trees

    PubMed Central

    Beikircher, Barbara; Mittmann, Claudia; Mayr, Stefan

    2016-01-01

    Restoration of an adequate water supply in spring is a prerequisite for survival of angiosperm trees in temperate regions. Trees must re-establish access to soil water and recover xylem functionality. We thus hypothesized that prolonged soil frost impairs recovery and affects hydraulics and phenology of Malus domestica var. ‘Golden Delicious.’ To test this hypothesis, over two consecutive winters the soil around some trees was insulated to prolong soil frosting, From mid-winter to early summer, the level of native embolism, the water and starch contents of wood, bark and buds were quantified at regular intervals and findings correlated with various phenological parameters, xylogenesis and fine root growth. The findings confirm that prolonged soil frost affects tree hydraulics and phenology but the severity of the effect depends on the climatic conditions. In both study years, percentage loss of hydraulic conductivity (PLC) decreased from about 70% at the end of winter to about 10% in May. Thereby, xylem refilling strongly coincided with a decrease of starch in wood and bark. Also treated trees were able to restore their hydraulic system by May but, in the warm spring of 2012, xylem refilling, the increases in water content and starch depolymerization were delayed. In contrast, in the cold spring of 2013 only small differences between control and treated trees were observed. Prolongation of soil frost also led to a delay in phenology, xylogenesis, and fine root growth. We conclude that reduced water uptake from frozen or cold soils impairs refilling and thus negatively impacts tree hydraulics and growth of apple trees in spring. Under unfavorable circumstances, this may cause severe winter damage or even dieback. PMID:27379146

  18. Carbon dioxide flux as affected by tillage and irrigation in soil converted from perennial forages to annual crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Among greenhouse gases, carbon dioxide (CO2) is one of the most significant contributors to regional and global warming as well as climatic change. However, CO2 flux from the soil surface to the atmosphere can be affected by modifications in soil physical properties resulting from changes in land ma...

  19. Physical, chemical, and biological properties of soils in the city of Mariupol, Ukraine

    NASA Astrophysics Data System (ADS)

    Shekhovtseva, O. G.; Mal'tseva, I. A.

    2015-12-01

    Physicochemical and biological properties of urbanized soils in the city of Mariupol have been considered in comparison with the background soils. The parametrical characteristics (abundance and biomass) of soil algal groups, the content of humus, the reaction of soil solution, the content of heavy metals, and the particle size distributions of soils under different anthropogenic impacts have been assessed. The physicochemical properties of soils developing under urboecosystem conditions affect the number of structure-forming species, biomass, and proportions of soil algae. According to the particle size distribution, urban soils are classified among the medium and heavy loamy soils with the predominance of the clay and coarse silt fractions. The fractions of physical clay and clay are of highest importance for the existence of algae. The accumulation of heavy metals in the surface horizons of soils can stimulate or inhibit the development of algae depending on the metal concentration.

  20. Nanoparticle characteristics affecting environmental fate and transport through soil.

    PubMed

    Darlington, Thomas K; Neigh, Arianne M; Spencer, Matthew T; Nguyen, Oanh T; Oldenburg, Steven J

    2009-06-01

    Nanoparticles are being used in broad range of applications; therefore, these materials probably will enter the environment during their life cycle. The objective of the present study is to identify changes in properties of nanoparticles released into the environment with a case study on aluminum nanoparticles. Aluminum nanoparticles commonly are used in energetic formulations and may be released into the environment during their handling and use. To evaluate the transport of aluminum nanoparticles, it is necessary not only to understand the properties of the aluminum in its initial state but also to determine how the nanoparticle properties will change when exposed to relevant environmental conditions. Transport measurements were conducted with a soil-column system that delivers a constant upflow of a suspension of nanoparticles to a soil column and monitors the concentration, size, agglomeration state, and charge of the particles in the eluent. The type of solution and surface functionalization had a marked effect on the charge, stability, and agglomeration state of the nanoparticles, which in turn impacted transport through the receiving matrix. Transport also is dependent on the size of the nanoparticles, although it is the agglomerate size, not the primary size, that is correlated with transportability. Electrostatically induced binding events of positively charged aluminum nanoparticles to the soil matrix were greater than those for negatively charged aluminum nanoparticles. Many factors influence the transport of nanoparticles in the environment, but size, charge, and agglomeration rate of nanoparticles in the transport medium are predictive of nanoparticle mobility in soil. PMID:19175296

  1. Tillage effects on physical properties in two soils of the Northern Great Plains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tillage practices profoundly affect soil physical and hydraulic properties. It is essential to select a tillage practice that sustains the soil physical properties required for successful growth of agricultural crops. We evaluated the effects of conventional (CT) and strip (ST) tillage practices on ...

  2. Spatial variability of soil properties and soil erodibility in the Alqueva reservoir watershed

    NASA Astrophysics Data System (ADS)

    Ferreira, V.; Panagopoulos, T.; Andrade, R.; Guerrero, C.; Loures, L.

    2015-04-01

    The aim of this work is to investigate how the spatial variability of soil properties and soil erodibility (K factor) were affected by the changes in land use allowed by irrigation with water from a reservoir in a semiarid area. To this end, three areas representative of different land uses (agroforestry grassland, lucerne crop and olive orchard) were studied within a 900 ha farm. The interrelationships between variables were analyzed by multivariate techniques and extrapolated using geostatistics. The results confirmed differences between land uses for all properties analyzed, which was explained mainly by the existence of diverse management practices (tillage, fertilization and irrigation), vegetation cover and local soil characteristics. Soil organic matter, clay and nitrogen content decreased significantly, while the K factor increased with intensive cultivation. The HJ-Biplot methodology was used to represent the variation of soil erodibility properties grouped in land uses. Native grassland was the least correlated with the other land uses. The K factor demonstrated high correlation mainly with very fine sand and silt. The maps produced with geostatistics were crucial to understand the current spatial variability in the Alqueva region. Facing the intensification of land-use conversion, a sustainable management is needed to introduce protective measures to control soil erosion.

  3. Spatial variability of soil properties and soil erodibility in the Alqueva dam watershed, Portugal

    NASA Astrophysics Data System (ADS)

    Ferreira, V.; Panagopoulos, T.; Andrade, R.; Guerrero, C.; Loures, L.

    2015-01-01

    The aim of this work is to investigate how the spatial variability of soil properties and soil erodibility (K factor) were affected by the changes in land use allowed by irrigation with water from a reservoir in a semiarid area. To this, three areas representative of different land uses (agroforestry grassland, Lucerne crop and olive orchard) were studied within a 900 ha farm. The interrelationships between variables were analyzed by multivariate techniques and extrapolated using geostatistics. The results confirmed differences between land uses for all properties analyzed, which was explained mainly by the existence of diverse management practices (tillage, fertilization and irrigation), vegetation cover and local soil characteristics. Soil organic matter, clay and nitrogen content decreased significantly, while K factor increased with intensive cultivation. The HJ-biplot methodology was used to represent the variation of soil erodibility properties grouped in land uses. Native grassland was the least correlated with the other land uses. K factor demonstrated high correlation mainly with very fine sand and silt. The maps produced with geostatistics were crucial to understand the current spatial variability in the Alqueva region. Facing the intensification of land-use conversion, a sustainable management is needed to introduce protective measures to control soil erosion.

  4. Contents and composition of organic matter in subsurface soils affected by land use and soil mineralogy

    NASA Astrophysics Data System (ADS)

    Ellerbrock, Ruth H.; Kaiser, Michael

    2010-05-01

    Land use and mineralogy affect the ability of surface as well as subsurface soils to sequester organic carbon and their contribution to mitigate the greenhouse effect. This study aimed to investigate the long-term impact of land use (i.e., arable and forest) and soil mineralogy on contents and composition of soil organic matter (SOM) from subsurface soils. Seven soils different in mineralogy (Albic and Haplic Luvisol, Colluvic and Haplic Regosol, Haplic and Vertic Cambisol, Haplic Stagnosol) were selected within Germany. Soil samples were taken from forest and adjacent arable sites. First, particulate and water soluble organic matter were separated from the subsurface soil samples. From the remaining solid residues the OM(PY) fractions were separated, analyzed for its OC content (OCPY) and characterized by FTIR spectroscopy. For the arable subsurface soils multiple regression analyses indicate significant positive relationships between the soil organic carbon contents and the contents of i) exchangeable Ca and oxalate soluble Fe, and Alox contents. Further for the neutral arable subsurface soils the contents OCPY weighted by its C=O contents were found to be related to the contents of Ca indicating interactions between OM(PY) and Ca cations. For the forest subsurface soils (pH <5) the OCPY contents were positively related with the contents of Na-pyrophosphate soluble Fe and Al. For the acidic forest subsurface soils such findings indicate interactions between OM(PY) and Fe3+ and Al3+ cations. The effects of land use and soil mineralogy on contents and composition of SOM and OM(PY) will be discussed.

  5. Effect of land management on soil properties in flood irrigated citrus orchards in Eastern Spain

    NASA Astrophysics Data System (ADS)

    Morugán-Coronado, A.; García-Orenes, F.; Cerdà, A.

    2015-01-01

    Agricultural land management greatly affects soil properties. Microbial soil communities are the most sensitive and rapid indicators of perturbations in land use and soil enzyme activities are sensitive biological indicators of the effects of soil management practices. Citrus orchards frequently have degraded soils and this paper evaluates how land management in citrus orchards can improve soil quality. A field experiment was performed in an orchard of orange trees (Citrus Sinensis) in the Alcoleja Experimental Station (Eastern Spain) with clay-loam agricultural soils to assess the long-term effects of herbicides with inorganic fertilizers (H), intensive ploughing and inorganic fertilizers (P) and organic farming (O) on the soil microbial properties, and to study the relationship between them. Nine soil samples were taken from each agricultural management plot. In all the samples the basal soil respiration, soil microbial biomass carbon, water holding capacity, electrical conductivity, soil organic matter, total nitrogen, available phosphorus, available potassium, aggregate stability, cation exchange capacity, pH, texture, macronutrients (Na, Ca and Mg), micronutrients (Fe, Mn, Zn and Cu), calcium carbonate equivalent, calcium carbonate content of limestone and enzimatic activities (urease, dehydrogenase, β-glucosidase and acid phosphatase) were determined. The results showed a substantial level of differentiation in the microbial properties, which were highly associated with soil organic matter content. The management practices including herbicides and intensive ploughing had similar results on microbial soil properties. O management contributed to an increase in the soil biology quality, aggregate stability and organic matter content.

  6. Spectral reflectance of surface soils: Relationships with some soil properties

    NASA Technical Reports Server (NTRS)

    Kiesewetter, C. H.

    1983-01-01

    Using a published atlas of reflectance curves and physicochemical properties of soils, a statistical analysis was carried out. Reflectance bands which correspond to five of the wavebands used by NASA's Thematic Mapper were examined for relationships to specific soil properties. The properties considered in this study include: Sand Content, Silt Content, Clay Content, Organic Matter Content, Cation Exchange Capacity, Iron Oxide Content and Moisture Content. Regression of these seven properties on the mean values of five TM bands produced results that indicate that the predictability of the properties can be increased by stratifying the data. The data was stratified by parent material, taxonomic order, temperature zone, moisture zone and climate (combined temperature and moisture). The best results were obtained when the sample was examined by climatic classes. The middle Infra-red bands, 5 and 7, as well as the visible bands, 2 and 3, are significant in the model. The near Infra-red band, band 4, is almost as useful and should be included in any studies. General linear modeling procedures examined relationships of the seven properties with certain wavebands in the stratified samples.

  7. How will climate change affect vine behaviour in different soils?

    NASA Astrophysics Data System (ADS)

    Leibar, Urtzi; Aizpurua, Ana; Morales, Fermin; Pascual, Inmaculada; Unamunzaga, Olatz

    2014-05-01

    and water-deficit had a clear influence on the grape phenological development and composition, whilst soil affected root configuration and anthocyanins concentration. Effects of climate change and water availability on different soil conditions should be considered to take full advantage or mitigate the consequences of the future climate conditions.

  8. Minimum property dataset and sampling requirement tool for soil change studies in soil survey

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dynamic soil properties (DSP) are those properties that change over human time scales. The new sampling guide “Soil and Resource Inventory Guide for Dynamic Soil Properties and Soil Change” includes a minimum DSP dataset and an interactive tool to determine sampling requirements. The minimum dataset...

  9. Copper phytoavailability and uptake by Elsholtzia splendens from contaminated soil as affected by soil amendments.

    PubMed

    Peng, Hong-Yun; Yang, Xiao-E; Jiang, Li-Ying; He, Zhen-Li

    2005-01-01

    Pot and field experiments were conducted to evaluate bioavailability of Cu in contaminated paddy soil (PS) and phytoremediation potential by Elsholtzia splendens as affected by soil amendments. The results from pot experiment showed that organic manure (M) applied to the PS not only remarkably raised the H2O exchangeable Cu, which were mainly due to the increased exchangeable and organic fractions of Cu in the PS by M, but also stimulated plant growth and Cu accumulation in E. splendens. At M application rate of 5.0%, shoot Cu concentration in the plant increased by four times grown on the PS, so as to the elevated shoot Cu accumulation by three times as compared to the control. In the field trial, soil amendments by M and furnace slag (F), and soil preparations like soil capping (S) and soil discing (D) were performed in the PS. Soil capping and discing considerably declined total Cu in the PS. Application of M solely or together with F enhanced plant growth and increased H2O exchangeable Cu levels in the soil. The increased extractability of Cu in the rhizosphere of E. splendens was noted, which may have mainly attributed to the rhizospheric acidification and chelation by dissolved organic matter (DOM), thus resulting in elevating Cu uptake and accumulation by E. splendens. Amendments with organic manure plus furnace slag (MF) to the PS caused the highest exactable Cu with saturated H2O in the rhizospheric soil of E. splendens after they were grown for 170 days in the PS, thus achieving 1.74 kg Cu ha(-1) removal from the contaminated soil by the whole plant of E. splendens at one season, which is higher than those of the other soil treatments. The results indicated that application of organic manure at a proper rate could enhance Cu bioavailability and increase effectiveness of Cu phytoextraction from the contaminated soil by the metal-tolerant and accumulating plant species (E. splendens). PMID:15792303

  10. Recovery approach affects soil quality in the water level fluctuation zone of the Three Gorges Reservoir, China: implications for revegetation.

    PubMed

    Ye, Chen; Cheng, Xiaoli; Zhang, Quanfa

    2014-02-01

    Plants in the water level fluctuation zone of the Three Gorges Reservoir Region disappeared due to winter-flooding and prolonged inundation. Revegetation (plantation and natural recovery) have been promoted to restore and protect the riparian ecosystem in recent years. Revegetation may affect soil qualities and have broad important implications both for ecological services and soil recovery. In this study, we investigated soil properties including soil pH values, bulk density, soil organic matter (SOM), soil nutrients and heavy metals, soil microbial community structure, microbial biomass, and soil quality index under plantation and natural recovery in the Three Gorges Reservoir Region. Most soil properties showed significant temporal and spatial variations in both the plantation and natural recovery areas. Higher contents of SOM and NO3-N were found in plantation area, while higher contents of soil pH values, bulk density, and total potassium were observed in the natural recovery area. However, there were no significant differences in plant richness and diversity and soil microbial community structure between the two restoration approaches. A soil quality index derived from SOM, bulk density, Zn, Cd, and Hg indicated that natural recovery areas with larger herbaceous coverage had more effective capacity for soil restoration. PMID:24019143

  11. Plant diversity and root traits benefit physical properties key to soil function in grasslands.

    PubMed

    Gould, Iain J; Quinton, John N; Weigelt, Alexandra; De Deyn, Gerlinde B; Bardgett, Richard D

    2016-09-01

    Plant diversity loss impairs ecosystem functioning, including important effects on soil. Most studies that have explored plant diversity effects belowground, however, have largely focused on biological processes. As such, our understanding of how plant diversity impacts the soil physical environment remains limited, despite the fundamental role soil physical structure plays in ensuring soil function and ecosystem service provision. Here, in both a glasshouse and a long-term field study, we show that high plant diversity in grassland systems increases soil aggregate stability, a vital structural property of soil, and that root traits play a major role in determining diversity effects. We also reveal that the presence of particular plant species within mixed communities affects an even wider range of soil physical processes, including hydrology and soil strength regimes. Our results indicate that alongside well-documented effects on ecosystem functioning, plant diversity and root traits also benefit essential soil physical properties. PMID:27459206

  12. Experimental design based on field spectrometry for characterization of fire-affected soils.

    NASA Astrophysics Data System (ADS)

    Rosero, Olga; Vlassova, Lidia; Montorio Llovería, Raquel; Pérez-Cabello, Fernando

    2014-05-01

    Wildfires can modify physical and chemical properties of soils (Mataix-Solera et al., 2011; Badía et al., 2014). These disturbances involve changes in soil spectral properties, which can be analyzed by using field spectrometry (VIS-SWIR) (Montorio et al., 2008; Guerrero et al., 2010). The aim of this study is to present an experimental design for hyperspectral characterization of fire affected soils in laboratory conditions. We analyzed soil samples from Montes de Zuera area (Aragón, Spain) repeatedly affected by wildfires in the period of 1979-2008. Fourteen samples, seven from the burned zones and the corresponding control samples were collected in spring of 2013. Spectral analysis was performed on subsamples of around 130 g (fine fraction, particle size < 2 mm), previously dried in a stove at 105°C during 36 hours, and placed in crystal petri dishes (90 mm x 15 mm). The spectra were obtained using spectroradiometer ASD FieldSpec® 4 (spectral range from 350 nm to 2500 nm) combined with a Contact Probe ensuring homogeneity of observation and illumination conditions. Spectralon reference panel Labsphere® was used for conversion to reflectance values. The resulting reflectance is an average of the measurements corresponding to five random points of the subsample, each of them representing a mean value of 10 spectra. The averaging of spectra improves the signal to noise ratio and, at the same time, it minimizes the variations caused by the samples surface roughness. Statistically significant differences have been detected between burned and control soils. Reflectance increase of 12% (average for the whole spectrum) was observed in 70% of the samples: 16%, 15% and 10% increase in visible, NIR and SWIR respectively. Therefore regardless of the wildfire date, an increase of reflectance is observed in burned soils due to changes on soil properties. A detailed analysis of physical, chemical and biological properties of soils will be used in further research to

  13. Metal Toxicity Affects Fungal and Bacterial Activities in Soil Differently

    PubMed Central

    Rajapaksha, R. M. C. P.; Tobor-Kapłon, M. A; Bååth, E.

    2004-01-01

    Although the toxic effect of heavy metals on soil microorganism activity is well known, little is known about the effects on different organism groups. The influence of heavy metal addition on total, bacterial, and fungal activities was therefore studied for up to 60 days in a laboratory experiment using forest soil contaminated with different concentrations of Zn or Cu. The effects of the metals differed between the different activity measurements. During the first week after metal addition, the total activity (respiration rate) decreased by 30% at the highest level of contamination and then remained stable during the 60 days of incubation. The bacterial activity (thymidine incorporation rate) decreased during the first days with the level of metal contamination, resulting in a 90% decrease at the highest level of contamination. Bacterial activity then slowly recovered to values similar to those of the control soil. The recovery was faster when soil pH, which had decreased due to metal addition, was restored to control values by liming. Fungal activity (acetate-in-ergosterol incorporation rate) initially increased with the level of metal contamination, being up to 3 and 7 times higher than that in the control samples during the first week at the highest levels of Zn and Cu addition, respectively. The positive effect of metal addition on fungal activity then decreased, but fungal activity was still higher in contaminated than in control soil after 35 days. This is the first direct evidence that fungal and bacterial activities in soil are differently affected by heavy metals. The different responses of bacteria and fungi to heavy metals were reflected in an increase in the relative fungal/bacterial ratio (estimated using phospholipid fatty acid analysis) with increased metal load. PMID:15128558

  14. Metal toxicity affects fungal and bacterial activities in soil differently.

    PubMed

    Rajapaksha, R M C P; Tobor-Kapłon, M A; Bååth, E

    2004-05-01

    Although the toxic effect of heavy metals on soil microorganism activity is well known, little is known about the effects on different organism groups. The influence of heavy metal addition on total, bacterial, and fungal activities was therefore studied for up to 60 days in a laboratory experiment using forest soil contaminated with different concentrations of Zn or Cu. The effects of the metals differed between the different activity measurements. During the first week after metal addition, the total activity (respiration rate) decreased by 30% at the highest level of contamination and then remained stable during the 60 days of incubation. The bacterial activity (thymidine incorporation rate) decreased during the first days with the level of metal contamination, resulting in a 90% decrease at the highest level of contamination. Bacterial activity then slowly recovered to values similar to those of the control soil. The recovery was faster when soil pH, which had decreased due to metal addition, was restored to control values by liming. Fungal activity (acetate-in-ergosterol incorporation rate) initially increased with the level of metal contamination, being up to 3 and 7 times higher than that in the control samples during the first week at the highest levels of Zn and Cu addition, respectively. The positive effect of metal addition on fungal activity then decreased, but fungal activity was still higher in contaminated than in control soil after 35 days. This is the first direct evidence that fungal and bacterial activities in soil are differently affected by heavy metals. The different responses of bacteria and fungi to heavy metals were reflected in an increase in the relative fungal/bacterial ratio (estimated using phospholipid fatty acid analysis) with increased metal load. PMID:15128558

  15. Determining soil moisture and soil properties in vegetated areas by assimilating soil temperatures

    NASA Astrophysics Data System (ADS)

    Dong, Jianzhi; Steele-Dunne, Susan C.; Ochsner, Tyson E.; van de Giesen, Nick

    2016-06-01

    This study addresses two critical barriers to the use of Passive Distributed Temperature Sensing (DTS) for large-scale, high-resolution monitoring of soil moisture. In recent research, a particle batch smoother (PBS) was developed to assimilate sequences of temperature data at two depths into Hydrus-1D to estimate soil moisture as well as soil thermal and hydraulic properties. However, this approach was limited to bare soil and assumed that the cable depths were perfectly known. In order for Passive DTS to be more broadly applicable as a soil hydrology research and remote sensing soil moisture product validation tool, it must be applicable in vegetated areas. To address this first limitation, the forward model (Hydrus-1D) was improved through the inclusion of a canopy energy balance scheme. Synthetic tests were used to demonstrate that without the canopy energy balance scheme, the PBS estimated soil moisture could be even worse than the open loop case (no assimilation). When the improved Hydrus-1D model was used as the forward model in the PBS, vegetation impacts on the soil heat and water transfer were well accounted for. This led to accurate and robust estimates of soil moisture and soil properties. The second limitation is that, cable depths can be highly uncertain in DTS installations. As Passive DTS uses the downward propagation of heat to extract moisture-related variations in thermal properties, accurate estimates of cable depths are essential. Here synthetic tests were used to demonstrate that observation depths can be jointly estimated with other model states and parameters. The state and parameter results were only slightly poorer than those obtained when the cable depths were perfectly known. Finally, in situ temperature data from four soil profiles with different, but known, soil textures were used to test the proposed approach. Results show good agreement between the observed and estimated soil moisture, hydraulic properties, thermal properties, and

  16. Multi-Sensor Estimation of Claypan Soil Profile Properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Large quantities of data are needed to solve land use and soil management problems, yet lab analysis of soil data is costly and time consuming. Soil property sensors on mobile platforms have the capability to estimate soil properties at many more locations than reference lab measurements. The fusion...

  17. Effects of soil tillage and management of crop residues on soil properties: abundance, biomass and diversity of earthworms, soil structure and nutrient evolutions

    NASA Astrophysics Data System (ADS)

    lemtiri, Aboulkacem

    2013-04-01

    The living soil is represented by soil biota that interacts with aboveground biota and with the abiotic environment, soil structure, soil reaction, organic matter, nutrient contents, aso. Maintenance of soil organic matter through integrated soil fertility management is an important issue to conciliate soil quality and agricultural productivity. Earthworms are key actors in soil structure formation through the production of casts and the incorporation of soil organic matter in the soil. Research is still needed about the interactive effects of various tillage and crop residue management practices on earthworm populations and physical and chemical properties of soil. To investigate the impacts of two tillage management systems and two cropping systems on earthworm populations, soil structure evolution and nutrient dynamics, we carried out a three years study in an experimental field. The aims of this experimentation, were to assess the effects of the tillage systems (ploughing versus reduced tillage) and the availability of crop residues (export versus no export) on (i) the abundance, biomass and diversity of earthworms, on the soil structure and on the temporal variation of water extractable nutrients and organic carbon. The first results show that tillage management did significantly affect earthworm abundance and biomass. However, crop residue management did not affect abundance, biomass and diversity of earthworms. Regarding soil physical properties, the tillage affected the compaction profiles within the top 30cm. The analysis of nutrient and organic carbon dynamics show divergent trends (decrease of calcium and magnesium, increase of hot water extractable carbon and phosphorus…) but no clear effect of the studied factors could be identified. The question of the initial soil variability raised as a crucial point in the discussion.

  18. Electrokinetic properties of soil minerals and soils modified with polyelectrolytes

    NASA Astrophysics Data System (ADS)

    Kurochkina, G. N.; Pinskii, D. L.; Haynos, M.; Sokolowska, Z.; Tsesla, I.

    2014-07-01

    The formation features of nanoadsorption polyelectrolyte (PE) layers with the formation of a mineral-organic matrix on the surface of clay minerals and soils (kaolinite, montmorillonite, quartz sand, gray forest soil, and chernozemic soil) have been elucidated by direct adsorption measurements. It has been found that the experimental values for the limit adsorption of polyacrylamide (PAM) and polyacrylic acid (PAA) on all the minerals are significantly higher than the calculated values for the formation of a monolayer. This indicates adsorption on the surface of not only separate macromolecules but also secondary PE structures as packets or fibrils determining the cluster-matrix structure of the modified surface. The study of the electro-surface properties (electrophoretic mobility, electrokinetic potential, pH, and electroconductivity) of mineral and soil particles adsorption-modified with PEs has confirmed the differences in the adsorption mechanisms (from physical sorption to chemisorption) with the formation of surface compounds depending on the different polar groups of PEs and the mineral type.

  19. Long-Term Tillage Affects on Soil Aggregation and Carbon Sequestration

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Continuous cultivation affects soil structure due to the destruction of soil aggregates and the lost of soil organic carbon (SOC). Different management practices, such as different tillage applications, affect the formation and the stabilization of soil aggregates through management effects on SOC l...

  20. Edaphic factors affecting the vertical distribution of radionuclides in the different soil types of Belgrade, Serbia.

    PubMed

    Dragović, Snežana; Gajić, Boško; Dragović, Ranko; Janković-Mandić, Ljiljana; Slavković-Beškoski, Latinka; Mihailović, Nevena; Momčilović, Milan; Ćujić, Mirjana

    2012-01-01

    The specific activities of natural radionuclides ((40)K, (226)Ra and (232)Th) and Chernobyl-derived (137)Cs were measured in soil profiles representing typical soil types of Belgrade (Serbia): chernozems, fluvisols, humic gleysols, eutric cambisols, vertisols and gleyic fluvisols. The influence of soil properties and content of stable elements on radionuclide distribution down the soil profiles (at 5 cm intervals up to 50 cm depth) was analysed. Correlation analysis identified associations of (40)K, (226)Ra and (137)Cs with fine-grained soil fractions. Significant positive correlations were found between (137)Cs specific activity and both organic matter content and cation exchange capacity. Saturated hydraulic conductivity and specific electrical conductivity were also positively correlated with the specific activity of (137)Cs. The strong positive correlations between (226)Ra and (232)Th specific activities and Fe and Mn indicate an association with oxides of these elements in soil. The correlations observed between (40)K and Cr, Ni, Pb and Zn and also between (137)Cs and Cd, Cr, Pb and Zn could be attributed to their common affinity for clay minerals. These results provide insight into the main factors that affect radionuclide migration in the soil, which contributes to knowledge about radionuclide behaviour in the environment and factors governing their mobility within terrestrial ecosystems. PMID:22072061

  1. Thallium isotope variations in anthropogenically-affected soils

    NASA Astrophysics Data System (ADS)

    Vanek, Ales; Chrastny, Vladislav; Penizek, Vit; Mihaljevic, Martin; Komarek, Michael; Cabala, Jerzy

    2014-05-01

    Our preliminary data from soils impacted by long-term Tl deposition in the vicinity of a primary/secondary Zn smelter at Olkusz (Poland) indicate apparent variability of ɛ205Tl within soil profiles. The identified ɛ205Tl values presented for the forest soil profile reached -1.7 in the surface/organic horizon, +1.9 in the organo-mineral horizon (Ap), and +1.0 in the mineral horizon (C). This finding suggests both the enrichment of 203Tl isotope in the topsoil, as well as its preferential release during smelting operations, as "lighter" Tl tends to enter the emissions during a high-temperature process. The maximum ɛ205Tl value in the subsurface horizon Ap is in accordance with the concentration peak of oxalate-extractable Mn, indicating the presence of amorphous/poorly-crystalline Mn oxides with a potential to isotopically fractionate Tl toward the "heavier" fraction. The Tl isotope signature in the bottom horizon probably reflects the composition of a local geochemical anomaly of Tl. However, a portion of mobile (anthropogenic) Tl with negative ɛ205Tl moving downwards in the soil profile cannot be neglected. In general, there is no detailed information about the biogeochemical cycling and variations of Tl isotopes in areas affected by significant anthropogenic inputs of the metal (e.g., coal burning and primary metallurgy); the questions of the degree to which the factors such as soil (and sediment) chemistry, mineralogy, local biota, and pollution source control Tl isotope fractionation remain unresolved. Therefore, further research on the topic is needed before any principal conclusions will be made.

  2. Wildfire effects on biological properties of soils in forest-steppe ecosystems of Russia

    NASA Astrophysics Data System (ADS)

    Maksimova, E.; Abakumov, E.

    2014-01-01

    Soils affected by forest wildfires in 2010 in Russia were studied on postfire and mature plots near the Togljatty city, Samara region. Soil biological properties and ash composition dynamics were investigated under the forest fire affect: a place of local forest fire, riding forest fire and unaffected site by fire-control (mature) during 3 yr of restoration. Soil samples were collected at 0-15 cm. Soil biological properties was measured by the fumigation method. The analytical data obtained shows that wildfires lead to serious changes in a soil profile and soil chemistry of upper horizons. Wildfires change a chemical composition of soil horizons and increase their ash-content. Fires lead to accumulation of biogenic elements' content (P and K) in the solum fine earth. Calcium content is increased as a result of fires that leads to an alkaline pH of the solum. The values of nutrients decreased as a result of leaching out with an atmospheric precipitation during the second year of restoration. Thus, when the upper horizons are burning the ash arriving on a soil surface enrich it with nutrients. The mature (unaffected by fire) soils is characterized by the greatest values of soil microbial biomass in the top horizon and, respectively, the bigger values of basal respiration whereas declining of the both parameters was revealed on postfire soils. Nevertheless this influence does not extend on depth more than 10 cm. Thus, fire affect on the soil were recognized in decreasing of microbiological activity.

  3. Coating agents affected toward magnetite nanoparticles properties

    NASA Astrophysics Data System (ADS)

    Petcharoen, Karat; Sirivat, Anuvat

    2012-02-01

    Magnetite nanoparticles --MNPs-- are innovative materials used in biological and medical applications. They respond to magnetic field through the superparamagnetic behavior at room temperature. In this study, the MNPs were synthesized via the chemical co-precipitation method using various coating agents. Fatty acids, found naturally in the animal fats, can be used as a coating agent. Oleic acid and hexanoic acid were chosen as the surface modification agents to study the improvement in the suspension of MNPs in water and the magnetite properties. Suspension stability, particle size, and electrical conductivity of MNPs are critically affected by the modification process. The well-dispersed MNPs in water can be improved by the surface modification and the oleic acid coated MNPs possess excellent suspension stability over 1 week. The particle size of MNPs increases up to 40 nm using oleic acid coated MNPs. The electrical conductivity of the smallest particle size is 1.3x10-3 S/cm, which is 5 times higher than that of the largest particle, suggesting potential applications as a biomedical material under both of the electrical and magnetic fields.

  4. Effect of soil hydraulic properties on the relationship between soil moisture variability and its mean value

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Knowledge of soil moisture and its variability is needed for many environmental applications. We analyzed dependencies of soil moisture variability on average soil moisture contents in bare soils using ensembles of non-stationary water flow simulations by varying soil hydraulic properties under diff...

  5. Observational Evidence that Soil Moisture Variations Affect Precipitation

    NASA Technical Reports Server (NTRS)

    Koster, Randal D.; Suarez, Max J.; Higgins, R. Wayne; VandenDool, Huug M.

    2002-01-01

    Land-atmosphere feedback, by which precipitation-induced soil moisture anomalies affect subsequent precipitation, may be an important element of Earth's climate system, but its very existence has never been demonstrated conclusively at regional to continental scales. Evidence for the feedback is sought in a 50-year observational precipitation dataset covering the United States. The precipitation variance and autocorrelation fields are characterized by features that agree (in structure, though not in magnitude) with those produced by an atmospheric general circulation model (AGCM). Because the model-generated features are known to result from land-atmosphere feedback alone, the observed features are highly suggestive of the existence of feedback in nature.

  6. The role of rock fragments in soils hydric properties

    NASA Astrophysics Data System (ADS)

    Tetegan, Marion; Cousin, Isabelle; Bouthier, Alain; Nicoullaud, Bernard

    2010-05-01

    Stony soils contain rock fragments, called stones, which limits some tillage operations. These soils often thin cover about 30% of the surface soils of Western Europe and 60% in Mediterranean areas. Though stony soils are widely spread and create problems to agriculture production, they have been little studied. As stones characterization is difficult, the stony phase is often neglected in the characterization of the properties of stony soils. However, some authors have demonstrated that the rock fragments could modify the physical, chemical and hydrodynamic properties of soils, and affect the behaviour and characteristics of agricultural soils. Indeed, the stony phase may participate in the water supply of crops and change the storage capacity of soil water. All these previous studies suggest some water transfers between the rock fragments and fine earth in soil. The objective of this work was to study the contribution of stony phase to the soil hydric properties by characterising the structure and the water retention capacity of rock fragments from different types of stony soils. The stones were sampled in the cultivated horizon (0 - 30 cm) of different types of stony soils in the Central part of France. Only the pebble fraction (2 cm < stone diameter < 5 cm) was studied. Most of the stones were collected when the soil was at field capacity. The pebbles were sampled in soils developed over sedimentary rocks and were of the following types: gaize, chalk, chert, flint, and limestone. The structure of each dry pebble was characterized by measurements of bulk density and density of solid, and by calculation of the void ratio of the sample. The porosity, but also bulk density and void ratio varied according to the type of stone, and within a single type of stone, and especially for the limestones. The hydric properties were determined by measurements of gravimetric water content when the pebbles were at saturation or after they were equilibrated at -100 hPa and -15000

  7. Relationships between soil properties and community structure of soil macroinvertebrates in oak-history forests along an acidic deposition gradient

    SciTech Connect

    Kuperman, R.G.

    1996-02-01

    Soil macroinvertebrate communities were studied in ecologically analogous oak-hickory forests across a three-state atmospheric pollution gradient in Illinois, Indiana, and Ohio. The goal was to investigate changes in the community structure of soil fauna in study sites receiving different amounts of acidic deposition for several decades and the possible relationships between these changes and physico-chemical properties of soil. The study revealed significant differences in the numbers of soil animals among the three study sites. The sharply differentiated pattern of soil macroinvertebrate fauna seems closely linked to soil chemistry. Significant correlations of the abundance of soil macroinvertebrates with soil parameters suggest that their populations could have been affected by acidic deposition in the region. Abundance of total soil macroinvertebrates decreased with the increased cumulative loading of acidic deposition. Among the groups most sensitive to deposition were: earthworms gastropods, dipteran larvae, termites, and predatory beetles. The results of the study support the hypothesis that chronic long-term acidic deposition could aversely affect the soil decomposer community which could cause lower organic matter turnover rates leading to an increase in soil organic matter content in high deposition sites.

  8. Macrofauna assemblage composition and soil moisture interact to affect soil ecosystem functions

    NASA Astrophysics Data System (ADS)

    Collison, E. J.; Riutta, T.; Slade, E. M.

    2013-02-01

    Changing climatic conditions and habitat fragmentation are predicted to alter the soil moisture conditions of temperate forests. It is not well understood how the soil macrofauna community will respond to changes in soil moisture, and how changes to species diversity and community composition may affect ecosystem functions, such as litter decomposition and soil fluxes. Moreover, few studies have considered the interactions between the abiotic and biotic factors that regulate soil processes. Here we attempt to disentangle the interactive effects of two of the main factors that regulate soil processes at small scales - moisture and macrofauna assemblage composition. The response of assemblages of three common temperate soil invertebrates (Glomeris marginata Villers, Porcellio scaber Latreille and Philoscia muscorum Scopoli) to two contrasting soil moisture levels was examined in a series of laboratory mesocosm experiments. The contribution of the invertebrates to the leaf litter mass loss of two common temperate tree species of contrasting litter quality (easily decomposing Fraxinus excelsior L. and recalcitrant Quercus robur L.) and to soil CO2 fluxes were measured. Both moisture conditions and litter type influenced the functioning of the invertebrate assemblages, which was greater in high moisture conditions compared with low moisture conditions and on good quality vs. recalcitrant litter. In high moisture conditions, all macrofauna assemblages functioned at equal rates, whereas in low moisture conditions there were pronounced differences in litter mass loss among the assemblages. This indicates that species identity and assemblage composition are more important when moisture is limited. We suggest that complementarity between macrofauna species may mitigate the reduced functioning of some species, highlighting the importance of maintaining macrofauna species richness.

  9. Variations in soil detachment rates after wildfire as a function of soil depth, flow properties, and root properties

    USGS Publications Warehouse

    Moody, John A.; Nyman, Peter

    2013-01-01

    Wildfire affects hillslope erosion through increased surface runoff and increased sediment availability, both of which contribute to large post-fire erosion events. Relations between soil detachment rate, soil depth, flow and root properties, and fire impacts are poorly understood and not represented explicitly in commonly used post-fire erosion models. Detachment rates were measured on intact soil cores using a modified tilting flume. The cores were mounted flush with the flume-bed and a measurement was made on the surface of the core. The core was extruded upward, cut off, and another measurement was repeated at a different depth below the original surface of the core. Intact cores were collected from one site burned by the 2010 Fourmile Canyon (FMC) fire in Colorado and from one site burned by the 2010 Pozo fire in California. Each site contained contrasting vegetation and soil types. Additional soil samples were collected alongside the intact cores and were analyzed in the laboratory for soil properties (organic matter, bulk density, particle-size distribution) and for root properties (root density and root-length density). Particle-size distribution and root properties were different between sites, but sites were similar in terms of bulk density and organic matter. Soil detachment rates had similar relations with non-uniform shear stress and non-uniform unit stream power. Detachment rates within single sampling units displayed a relatively weak and inconsistent relation to flow variables. When averaged across all clusters, the detachment rate displayed a linear relation to shear stress, but variability in soil properties meant that the shear stress accounted for only a small proportion of the overall variability in detachment rates (R2 = 0.23; R2 is the coefficient of determination). Detachment rate was related to root-length density in some clusters (R2 values up to 0.91) and unrelated in others (R2 values 2 value improved and the range of exponents became

  10. The diversity of permafrost-affected soils in the Lena River Delta and its hinterland

    NASA Astrophysics Data System (ADS)

    Zubrzycki, Sebastian; Kutzbach, Lars; Yakshina, Irina; Pfeiffer, Eva-Maria

    2013-04-01

    The North-Siberian Lena River Delta is the largest Arctic delta and an important interface between the Arctic Ocean in the North and the large Siberian land masses in the South. This delta consists not only of Holocene deltaic sediment deposits as a river terrace and the modern active floodplains but also of remnants of the former Pleistocene mainland including large islands of ice-complex sediments and the Arga-Muora-Sise Island, which is composed of pure sand sediments of still debated origin. The highly diverse landscape structure of the Lena River Delta is reflected by a great variety of permafrost-affected soils (gelisols). This study aims at describing this great gelisol diversity and at analysing the dominant soil-forming processes in this comparatively scarcely studied soil region. The soil development in the investigated continuous permafrost region is limited by the short thawing period of around three months (June to September) and takes place in the shallow (< 1 m) seasonally thawed active layer. The geological parent material plays an important role for the development of soils in the Lena River Delta region. The distribution of the various soil types closely follows the pattern of the geomorphic units characterised by differing sedimentation conditions. The properties and genesis of the soils on the Holocene river terrace and the modern floodplains are strongly affected by the enormous amounts of fluvial sediments (about 12 x 106 tons per year) brought by the Lena River into its delta. The fluvial sedimentation together with the also pronounced aeolian sedimentation results in a fast vertical growth of soils. The upward rise of the soil surface leads to an upward movement of the permafrost table resulting in fast incorporation of soil material formed in the supra-permafrost zone into the permafrost. Due to the morphodynamics of ice-wedge polygons and resulting formation of patterned ground with elevated rims and depressed and water-saturated centres

  11. Soil hydrological and soil property changes resulting from termite activity on agricultural fields in Burkina Faso

    NASA Astrophysics Data System (ADS)

    Mettrop, I.; Cammeraat, L. H.; Verbeeten, E.

    2009-04-01

    Termites are important ecosystem-engineers in subtropical and tropical regions. The effect of termite activity affecting soil infiltration is well documented in the Sahelian region. Most studies find increased infiltration rates on surfaces that are affected by termite activity in comparison to crusted areas showing non-termite presence. Crusted agricultural fields in the Sanmatenga region in Burkina Faso with clear termite activity were compared to control fields without visual ground dwelling termite activity. Fine scale rainfall simulations were carried out on crusted termite affected and control sites. Furthermore soil moisture change, bulk density, soil organic matter as well as general soil characteristics were studied. The top soils in the study area were strongly crusted (structural crust) after the summer rainfall and harvest of millet. They have a loamy sand texture underlain by a shallow sandy loam Bt horizon. The initial soil moisture conditions were significantly higher on the termite plots when compared to control sites. It was found that the amount of runoff produced on the termite plots was significantly higher, and also the volumetric soil moisture content after the experiments was significantly lower if compared to the control plots. Bulk density showed no difference whereas soil organic matter was significantly higher under termite affected areas, in comparison to the control plots. Lab tests showed no significant difference in hydrophobic behavior of the topsoil and crust material. Micro and macro-structural properties of the topsoil did not differ significantly between the termite sites and the control sites. The texture of the top 5 cm of the soil was also found to be not significantly different. The infiltration results are contradictory to the general literature, which reports increased infiltration rates after prolonged termite activity although mostly under different initial conditions. The number of nest entrances was clearly higher in

  12. Microbial Carbon Cycling in Permafrost-Affected Soils

    SciTech Connect

    Vishnivetskaya, T.; Liebner, Susanne; Wilhelm, Ronald; Wagner, Dirk

    2011-01-01

    The Arctic plays a key role in Earth s climate system as global warming is predicted to be most pronounced at high latitudes and because one third of the global carbon pool is stored in ecosystems of the northern latitudes. In order to improve our understanding of the present and future carbon dynamics in climate sensitive permafrost ecosystems, present studies concentrate on investigations of microbial controls of greenhouse gas fluxes, on the activity and structure of the involved microbial communities, and on their response to changing environmental conditions. Permafrost-affected soils can function as both a source and a sink for carbon dioxide and methane. Under anaerobic conditions, caused by flooding of the active layer and the effect of backwater above the permafrost table, the mineralization of organic matter can only be realized stepwise by specialized microorganisms. Important intermediates of the organic matter decomposition are hydrogen, carbon dioxide and acetate, which can be further reduced to methane by methanogenic archaea. Evolution of methane fluxes across the subsurface/atmosphere boundary will thereby strongly depend on the activity of anaerobic methanogenic archaea and obligately aerobic methane oxidizing proteobacteria, which are known to be abundant and to significantly reduce methane emissions in permafrost-affected soils. Therefore current studies on methane-cycling microorganisms are the object of particular attention in permafrost studies, because of their key role in the Arctic methane cycle and consequently of their significance for the global methane budget.

  13. Soil amendment affects Cd uptake by wheat - are we underestimating the risks from chloride inputs?

    PubMed

    Dahlin, A Sigrun; Eriksson, Jan; Campbell, Colin D; Öborn, Ingrid

    2016-06-01

    Many parts of the world are investigating the efficacy of recycling nutrient resources to agriculture from different industry and domestic sectors as part of a more circular economy. The complex nature of recycled products as soil amendments coupled to the large diversity of soil types and their inherent properties make it difficult to optimize the benefits and minimize the risks from potentially toxic elements often present in recycled materials. Here we investigated how wheat grain cadmium (Cd) concentration was affected by soil amendments, namely human urine and biogas digestate compared to traditional farm manures and mineral fertilizers. We show that Cl(-) inadvertently added to soils with e.g. urine or biogas digestate strongly increased crop Cd concentrations, largely by mobilizing inherent soil Cd. This resulted in wheat grain Cd levels that could result in exceeding recommended WHO limits for dietary intake. This was evident even in soils with low inherent Cd content and when Cd inputs were low. The future of a circular economy that helps to underpin global food security needs to ensure that the effects of applying complex materials to different types of agricultural land are fully understood and do not jeopardize food safety. PMID:26974588

  14. Exploring functional relationships between post-fire soil water repellency, soil structure and physico-chemical properties

    NASA Astrophysics Data System (ADS)

    Quarfeld, Jamie; Brook, Anna; Keestra, Saskia; Wittenberg, Lea

    2016-04-01

    Soil water repellency (WR) and aggregate stability (AS) are two soil properties that are typically modified after burning and impose significant influence on subsequent hydrological and geomorphological dynamics. The response of AS and soil WR to fire depends upon how fire has influenced other key soil properties (e.g. soil OM, mineralogy). Meanwhile, routine thinning of trees and woody vegetation may alter soil properties (e.g. structure and porosity, wettability) by use of heavy machinery and species selection. The study area is situated along a north-facing slope of Mount Carmel national park (Israel). The selected sites are presented as a continuum of management intensity and fire histories. To date, the natural baseline of soil WR has yet to be thoroughly assessed and must be investigated alongside associated soil aggregating parameters in order to understand its overall impact. This study examines (i) the natural baseline of soil WR and physical properties compared to those of disturbed sites in the immediate (controlled burn) and long-term (10-years), and (ii) the interactions of soil properties with different control factors (management, surface cover, seasonal-temporal, burn temperature, soil organic carbon (OC) and mineralogy) in Mediterranean calcareous soils. Analysis of surface soil samples before and after destruction of WR by heating (200-600°C) was implemented using a combination of traditional methods and infrared (IR) spectroscopy. Management and surface cover type conditioned the wettability, soil structure and porosity of soils in the field, although this largely did not affect the heat-induced changes observed in the lab. A positive correlation was observed along an increasing temperature gradient, with relative maxima of MWD and BD reached by most soils at the threshold of 400-500°C. Preliminary analyses of soil OC (MIR) and mineralogical composition (VIS-NIR) support existing research regarding: (i) the importance of soil OC quality and

  15. Soil carbon dioxide fluxes in relation to physical properties as influenced by management practices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Among greenhouse gases, carbon dioxide (CO2) is one of the most significant contributors to regional and global warming as well as climatic change. However, CO2 flux from the soil surface to the atmosphere can be affected by modifications in soil physical properties resulting from changes in land ma...

  16. Tillage depth effects on soil physical properties, sugarbeet yield and quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Tillage depth influences the soil-water-plant ecosystem, thereby affecting crop yield and quality. The effects of tillage depth on soil physical properties and sugarbeet (Beta vulgaris L.) yield and quality were evaluated. A field study comprised of two tillage depths: shallow (ST) of 10-cm and deep...

  17. The effects of soil properties on the turbidity of catchment soils from the Yongdam dam basin in Korea.

    PubMed

    Hur, Jin; Jung, Myung Chae

    2009-06-01

    Environmental concerns have been raised that suspended solids in turbid water adversely affect human health, and that their removal increases in the cost of water treatment. The Yongdam dam reservoir, located in the southwestern region of Korea, is severely affected by inflowing turbid water after storms. In this study, soil samples were collected from 37 sites in the Yongdam upstream basin to investigate mineralogical and environmental factors associated with the turbidity potential of soils in water environments. Turbidity potential was estimated by measuring the turbidity of soil-suspension solutions after settling for 24 h. The mineralogy of the soils was dominated by four minerals-quartz, microcline, albite, and muscovite-with lesser amounts of hornblende, chlorite, kaolinite, illite, and mixed layer illite. The quartz content was the most variable of the soil mineralogy among the collected samples. Principal-components analysis (PCA) was used to examine relationships between turbidity potential and other soil properties. The variables considered in the PCA included turbidity potential, quartz content, albite content, mean size of soil particles, clay content, clay mineral content, zeta potential, conductivity, and pH of the soil-suspension solution. The first two components of the PCA explained 52% of the overall variation of the selected variables. The first component was possibly explained by physical properties such as the size of the soil particles; the second was correlated with chemical properties of the soils, for example dissolution and extent of weathering. Closer examination of the PCA results revealed that the quartz content of the soils was negatively correlated with their turbidity potential. A linear correlation (r = 0.63) was obtained between measured turbidity potential and that predicted using multiple regression analysis based on the content of clay-sized particles, clay minerals, and quartz, and the conductivity of the soil

  18. Spatial variability of magnetic soil properties

    NASA Astrophysics Data System (ADS)

    van Dam, Remke L.; Hendrickx, Jan M.; Harrison, Bruce; Borchers, Brian; Norman, David I.; Ndur, Samuel; Jasper, Chris; Niemeyer, Patrick; Nartey, Robert; Vega, David N.; Calvo, Lucas; Simms, Janet E.

    2004-09-01

    The presence of magnetic iron oxides in the soil can seriously hamper the performance of electromagnetic sensors for the detection of buried land mines and unexploded ordnance (UXO). Previous work has shown that spatial variability in soil water content and texture affects the performance of ground penetrating radar and thermal sensors for land mine detection. In this paper we aim to study the spatial variability of iron oxides in tropical soils and the possible effect on electromagnetic induction sensors for buried low-metal land mine and UXO detection. We selected field sites in Panama, Hawaii, and Ghana. Along several horizontal transects in Panama and Hawaii we took closely spaced magnetic susceptibility readings using Bartington MS2D and MS2F sensors. In addition to the field measurements, we took soil samples from the selected sites for laboratory measurements of dual frequency magnetic susceptibility and textural characteristics of the material. The magnetic susceptibility values show a significant spatial variation in susceptibility and are comparable to values reported to hamper the operation of metal detectors in parts of Africa and Asia. The absolute values of susceptibility do not correlate with both frequency dependence and total iron content, which is an indication of the presence of different types of iron oxides in the studied material.

  19. Using 137 Cs measurements to investigate the influence of erosion and soil redistribution on soil properties.

    PubMed

    Du, P; Walling, D E

    2011-05-01

    Information on the interaction between soil erosion and soil properties is an important requirement for sustainable management of the soil resource. The relationship between soil properties and the soil redistribution rate, reflecting both erosion and deposition, is an important indicator of this interaction. This relationship is difficult to investigate using traditional approaches to documenting soil redistribution rates involving erosion plots and predictive models. However, the use of the fallout radionuclide (137)Cs to document medium-term soil redistribution rates offers a means of overcoming many of the limitations associated with traditional approaches. The study reported sought to demonstrate the potential for using (137)Cs measurements to assess the influence of soil erosion and redistribution on soil properties (particle size composition, total C, macronutrients N, P, K and Mg, micronutrients Mn, Mo, Fe, Cu and Zn and other elements, including Ti and As). (137)Cs measurements undertaken on 52 soil cores collected within a 7 ha cultivated field located near Colebrooke in Devon, UK were used to establish the magnitude and spatial pattern of medium-term soil redistribution rates within the field. The soil redistribution rates documented for the individual sampling points within the field ranged from an erosion rate of -12.9 t ha(-1) yr(-1) to a deposition rate of 19.2 t ha(-1) yr(-1). Composite samples of surface soil (0-5 cm) were collected immediately adjacent to each coring point and these samples were analysed for a range of soil properties. Individual soil properties associated with these samples showed significant variability, with CV values generally lying in the range 10-30%. The relationships between the surface soil properties and the soil redistribution rate were analysed. This analysis demonstrated statistically significant relationships between some soil properties (total phosphorus, % clay, Ti and As) and the soil redistribution rate, but for

  20. Scaling preferential flow processes in agricultural soils affected by tillage and trafficking at the field scale

    NASA Astrophysics Data System (ADS)

    Filipović, Vilim; Coquet, Yves

    2016-04-01

    There is an accumulation of experimental evidences that agricultural soils, at least the top horizons affected by tillage practices, are not homogeneous and present a structure that is strongly dependent on farming practices like tillage and trafficking. Soil tillage and trafficking can create compacted zones in the soil with hydraulic properties and porosity which are different from those of the non-compacted zones. This spatial variability can strongly influence transport processes and initiate preferential flow. Two or three dimensional models can be used to account for spatial variability created by agricultural practices, but such models need a detailed assessment of spatial heterogeneity which can be rather impractical to provide. This logically raises the question whether and how one dimensional model may be designed and used to account for the within-field spatial variability in soil structure created by agricultural practices. Preferential flow (dual-permeability) modelling performed with HYDRUS-1D will be confronted to classical modelling based on the Richards and convection-dispersion equations using HYDRUS-2D taking into account the various soil heterogeneities created by agricultural practices. Our goal is to derive one set of equivalent 1D soil hydraulic parameters from 2D simulations which accounts for soil heterogeneities created by agricultural operations. A field experiment was carried out in two phases: infiltration and redistribution on a plot by uniform sprinkle irrigation with water or bromide solution. Prior to the field experiment the soil structure of the tilled layer was determined along the face of a large trench perpendicular to the tillage direction (0.7 m depth and 3.1 m wide). Thirty TDR probes and tensiometers were installed in different soil structural zones (Δ compacted soil and Γ macroporous soil) which ensured soil water monitoring throughout the experiment. A map of bromide was constructed from small core samples (4 cm diam

  1. Photometric properties of Mars soils analogs

    USGS Publications Warehouse

    Pommerol, A.; Thomas, N.; Jost, B.; Beck, P.; Okubo, C.; McEwen, A.S.

    2013-01-01

    We have measured the bidirectional reflectance of analogs of dry, wet, and frozen Martian soils over a wide range of phase angles in the visible spectral range. All samples were produced from two geologic samples: the standard JSC Mars-1 soil simulant and Hawaiian basaltic sand. In a first step, experiments were conducted with the dry samples to investigate the effects of surface texture. Comparisons with results independently obtained by different teams with similar samples showed a satisfying reproducibility of the photometric measurements as well as a noticeable influence of surface textures resulting from different sample preparation procedures. In a second step, water was introduced to produce wet and frozen samples and their photometry investigated. Optical microscope images of the samples provided information about their microtexture. Liquid water, even in relatively low amount, resulted in the disappearance of the backscattering peak and the appearance of a forward-scattering peak whose intensity increases with the amount of water. Specular reflections only appeared when water was present in an amount large enough to allow water to form a film at the surface of the sample. Icy samples showed a wide variability of photometric properties depending on the physical properties of the water ice. We discuss the implications of these measurements in terms of the expected photometric behavior of the Martian surface, from equatorial to circum-polar regions. In particular, we propose some simple photometric criteria to improve the identification of wet and/or icy soils from multiple observations under different geometries.

  2. Photometric properties of Mars soils analogs

    NASA Astrophysics Data System (ADS)

    Pommerol, A.; Thomas, N.; Jost, B.; Beck, P.; Okubo, C.; McEwen, A. S.

    2013-10-01

    We have measured the bidirectional reflectance of analogs of dry, wet, and frozen Martian soils over a wide range of phase angles in the visible spectral range. All samples were produced from two geologic samples: the standard JSC Mars-1 soil simulant and Hawaiian basaltic sand. In a first step, experiments were conducted with the dry samples to investigate the effects of surface texture. Comparisons with results independently obtained by different teams with similar samples showed a satisfying reproducibility of the photometric measurements as well as a noticeable influence of surface textures resulting from different sample preparation procedures. In a second step, water was introduced to produce wet and frozen samples and their photometry investigated. Optical microscope images of the samples provided information about their microtexture. Liquid water, even in relatively low amount, resulted in the disappearance of the backscattering peak and the appearance of a forward-scattering peak whose intensity increases with the amount of water. Specular reflections only appeared when water was present in an amount large enough to allow water to form a film at the surface of the sample. Icy samples showed a wide variability of photometric properties depending on the physical properties of the water ice. We discuss the implications of these measurements in terms of the expected photometric behavior of the Martian surface, from equatorial to circum-polar regions. In particular, we propose some simple photometric criteria to improve the identification of wet and/or icy soils from multiple observations under different geometries.

  3. Soil Organic Carbon Pools and Stocks in Permafrost-Affected Soils on the Tibetan Plateau

    PubMed Central

    Dörfer, Corina; Kühn, Peter; Baumann, Frank; He, Jin-Sheng; Scholten, Thomas

    2013-01-01

    The Tibetan Plateau reacts particularly sensitively to possible effects of climate change. Approximately two thirds of the total area is affected by permafrost. To get a better understanding of the role of permafrost on soil organic carbon pools and stocks, investigations were carried out including both discontinuous (site Huashixia, HUA) and continuous permafrost (site Wudaoliang, WUD). Three organic carbon fractions were isolated using density separation combined with ultrasonic dispersion: the light fractions (<1.6 g cm−3) of free particulate organic matter (FPOM) and occluded particulate organic matter (OPOM), plus a heavy fraction (>1.6 g cm−3) of mineral associated organic matter (MOM). The fractions were analyzed for C, N, and their portion of organic C. FPOM contained an average SOC content of 252 g kg−1. Higher SOC contents (320 g kg−1) were found in OPOM while MOM had the lowest SOC contents (29 g kg−1). Due to their lower density the easily decomposable fractions FPOM and OPOM contribute 27% (HUA) and 22% (WUD) to the total SOC stocks. In HUA mean SOC stocks (0–30 cm depth) account for 10.4 kg m−2, compared to 3.4 kg m−2 in WUD. 53% of the SOC is stored in the upper 10 cm in WUD, in HUA only 39%. Highest POM values of 36% occurred in profiles with high soil moisture content. SOC stocks, soil moisture and active layer thickness correlated strongly in discontinuous permafrost while no correlation between SOC stocks and active layer thickness and only a weak relation between soil moisture and SOC stocks could be found in continuous permafrost. Consequently, permafrost-affected soils in discontinuous permafrost environments are susceptible to soil moisture changes due to alterations in quantity and seasonal distribution of precipitation, increasing temperature and therefore evaporation. PMID:23468904

  4. Soil organic matter dynamics under Beech and Hornbeam as affected by soil biological activity

    NASA Astrophysics Data System (ADS)

    Kooijman, A. M.; Cammeraat, L. H.

    2009-04-01

    Organic matter dynamics are highly affected both the soil fauna as well as the source of organic matter, having important consequences for the spatial heterogeneity of organic matter storage and conversion. We studied oldgrowth mixed deciduous forests in Central-Luxemburg on decalcified dolomitic marl, dominated by high-degradable hornbeam (Carpinus betulus L.) or low-degradable beech (Fagus sylvatica L.). Decomposition was measured both in the laboratory and in the field. Litter decomposition was higher for hornbeam than for beech under laboratory conditions, but especially in the field, which is mainly to be attributed to macro-fauna activity, specifically to earthworms (Lumbricus terrestris and Allolobophora species). We also investigated differences between beech and hornbeam with regard to litter input and habitat conditions. Total litter input was the same, but contribution of beech and hornbeam litter clearly differed between the two species. Also, mass of the ectorganic horizon and soil C:N ratio were significantly higher for beech, which was reflected in clear differences in the development of ectorganic profiles on top of the soil. Under beech a mull-moder was clearly present with a well developed fermentation and litter horizon, whereas under hornbeam all litter is incorporated into the soil, leaving the mineral soil surface bear in late summer (mull-type of horizon). In addition to litter quality, litter decomposition was affected by pH and soil moisture. Both pH and soil moisture were higher under hornbeam than under beech, which may reflect differences in soil development and litter quality effects over longer time scales. Under beech, dense layers of low-degradable litter may prevent erosion, and increase clay eluviation and leaching of base cations, leading to acid and dry conditions, which further decrease litter decay. Under hornbeam, the soil is not protected by a litter layer, and clay eluviation and acidification may be counteracted by erosion

  5. Organic matter protection as affected by the mineral soil matrix: allophanic vs. non-allophanic volcanic ash soils

    NASA Astrophysics Data System (ADS)

    Nierop, K. G. J.; Kaal, J.; Jansen, B.; Naafs, D. F. W.

    2009-04-01

    Volcanic ash soils (Andosols) contain the largest amounts of organic carbon of all mineral soil types. Chemical (complexes of organic matter with allophane, Al/Fe) and physical (aggregation) mechanisms are protecting the carbon from decomposition. While allophanic Andosols are dominated by short range order minerals such as allophane, imogolite and ferrihydrite, organic matter-Al/Fe complexes dominate non-allophanic Andosols. Consequently, chemical interactions between the mineral soil matrix and organic matter differ between these two soil types. This difference could potentially lead to different organic matter compositions. In this study, the organic matter of Ah horizons of an allophanic Andosol with a non-allophanic Andosol from Madeira Island is compared using analytical pyrolysis. Both volcanic soil types showed a relative decrease of lignin-derived pyrolysis products with depth, but this decrease was more pronounced in the allophanic Andosol. Polysaccharides were more abundant in the allophanic Ah horizon, particularly at lower depth, and this was also the case for the non-plant-derived N-containing polysaccharide chitin. Most likely, these biopolymers are adsorbed onto short range order minerals such as allophane and therefore were better protected in the allophanic Andosol. In addition, the higher chitin contents combined with the more pronounced lignin degradation suggests a higher fungal activity. Aliphatic pyrolysis products (n-alkenes/n-alkanes, fatty acids) were relatively more enriched in the non-allophanic Andosol. Lower microbial activity caused by the more acidic pH and higher levels of (toxic) aluminium are the most plausible reasons for the accumulation of these compounds in the non-allophanic Andosol. Although the allophanic and non-allophanic Andosol resembled each other in containing biopolymer groups of the same orders of magnitudes, in particular the contents of chitin and aliphatic compounds were distinctly affected by the differences in

  6. Flow Cell Sampling Technique: A new approach to analyze physical soil and particle surface properties of undisturbed soil samples

    NASA Astrophysics Data System (ADS)

    Krueger, Jiem; Leue, Martin; Heinze, Stefanie; Bachmann, Jörg

    2016-04-01

    During unsaturated water conditions, water flow occurs in the soil mainly by water film flow and depends on moisture content and pore surface properties. More attention is attributed to coatings enclosing soil particles and thus may affect wetting properties as well as hydraulic soil functions. Particle coatings are most likely responsible for many adsorption processes and are expected to favor local heterogeneous microstructure with enhanced biological activity. Many of the effects described cannot be detected on the basis of conventional soil column experiments, which were usually made to study soil hydraulic processes or surface - soil solution exchange processes. The general objective of this study was to develop a new field sampling method to unravel heterogeneous flow processes on small scales in an undisturbed soil under controlled lab conditions. This will be done by using modified flow cells (Plexiglas). Beside the measurements within a flow cell as breakthrough curves, the developed technique has several additional advantages in contrast to common columns or existing flow chamber/cell designs. The direct modification from the sampling frame to the flow cell provides the advantage to combine several analyses. The new technique enables to cut up to 5 thin undisturbed soil slices (quasi-replicates) down to 10 and/or 5 mm. Relative large particles, for instance, may limit this sampling method. The large observation area of up to 150 cm2 allows the characterization of particle surface properties in a high spatial resolution within an undisturbed soil sample. This sampling technique, as shown in our study, has the opportunity to link soil wetting hydraulic and several particle surface properties to spatial soil heterogeneities. This was shown with tracer experiments, small-scale contact angle measurements and analyses of the spatial distribution of functional groups of soil organic matter via DRIFT mapping.

  7. Cotton Production Practices Change Soil Properties

    NASA Astrophysics Data System (ADS)

    Blaise, D.; Singh, J. V.

    2012-04-01

    Historically, indigenous Asiatic cottons (Gossypium arboreum) were cultivated with minimal inputs in India. The introduction of the Upland cottons (G. hirsutum) and later the hybrid (H-4) triggered a whole set of intensified agronomic management with reliance on high doses of fertilisers and pesticide usage. In 2002, the transgenic Bt cotton hybrids were introduced and released for commercial cultivation. Presently, more than 95% of the nearly 12.2 million hectares of cotton area is under the Bt transgenic hybrids. These hybrids are not only high yielding but have reduced the dependence on pesticide because of an effective control of the lepidopteran pests. Thus, a change in the management practices is evident over the years. In this paper, we discuss the impact of two major agronomic management practices namely, nutrient management and tillage besides organic cotton cultivation in the rainfed cotton growing regions of central India characterized by sub-humid to semi-arid climate and dominated by Vertisols. Long-term studies at Nagpur, Maharashtra indicated the importance of integrated nutrient management (INM) wherein a part of the nutrient needs through fertiliser was substituted with organic manures such as farmyard manure (FYM). With the application of mineral fertilisers alone, soils became deficient in micronutrients. This was not observed with the FYM amended plots. Further, the manure amended plots had a better soil physical properties and the water holding capacity of the soil improved due to improvements in soil organic matter (SOM). Similarly, in a separate experiment, an improvement in SOM was observed in the organically managed fields because of continuous addition of organic residues. Further, it resulted in greater biological activity compared to the conventionally managed fields. Conservation tillage systems such as reduced tillage (RT) are a means to improve soil health and crop productivity. Long-term studies on tillage practices such as

  8. DEPTH DISTRIBUTION OF SOIL ORGANIC MATTER AND ITS CONSEQUENCES ON SOIL PROPERTIES AND CROP PRODUCTIVITY

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil organic matter is a key component of soil quality that sustains many key soil functions by providing the energy, substrates, and biological diversity to support biological activity, which affects aggregation (important for habitat space, oxygen supply, and preventing soil erosion), infiltration...

  9. Soil organic matter transformation in cryoturbated horizons of permafrost affected soils

    NASA Astrophysics Data System (ADS)

    Capek, Petr; Diakova, Katerina; Dickopp, Jan-Erik; Barta, Jiri; Santruckova, Hana; Wild, Birgit; Schnecker, Joerg; Guggenberg, Georg; Gentsch, Norman; Hugelius, Gustaf; Kuhry, Peter; Lashchinsky, Nikolaj; Gittel, Antje; Schleper, Christa; Mikutta, Robert; Palmtag, Juri; Shibistova, Olga; Urich, Tim; Zimov, Sergey; Richter, Andreas

    2014-05-01

    Cryoturbated soil horizons are special feature of permafrost affected soils. These soils are known to store great amount of organic carbon and cryoturbation undoubtedly contribute to it to large extent. Despite this fact there is almost no information about soil organic matter (SOM) transformation in cryoturbated horizons. Therefore we carried out long term incubation experiment in which we inspect SOM transformation in cryoturbated as well as in organic and mineral soil horizons under different temperature and redox regimes as potential drivers. We found out that lower SOM transformation in cryoturbated horizons compared to organic horizons was mainly limited by the amount of microbial biomass, which is extremely low in absolute numbers or expressed to SOM concentration. The biochemical transformation ensured by extracellular enzymes is relatively high leading to high concentrations of dissolved organic carbon in cryoturbated horizons. Nevertheless the final step of SOM transformation leading to C mineralization to CO2 or CH4 seems to be restricted by low microbial biomass. Critical step of biochemical transformation of complex SOM is dominated by phenoloxidases, which break down complex organic compounds to simple ones. Their oxygen consumption greatly overwhelms oxygen consumption of the whole microbial community. However the phenoloxidase activity shows strong temperature response with optimum at 13.7° C. Therefore we suggest that apparent SOM stability in cryoturbated horizons, which is expressed in old C14 dated age, is caused by low amount of microbial biomass and restricted diffusion of oxygen to extracellular enzymes in field.

  10. Infrared warming affects intrarow soil carbon dioxide efflux during early vegetative growth of spring wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Global warming will likely affect carbon cycles in agricultural soils. Our objective was to deploy infrared (IR) warming to characterize the effect of global warming on soil temperature (Ts), volumetric soil-water content ('s), and intrarow soil CO2 efflux (Fs) of an open-field spring wheat (Triticu...

  11. Do soil Fe transformation and secretion of low-molecular-weight organic acids affect the availability of Cd to rice?

    PubMed

    Chen, Xue; Yang, Yazhou; Liu, Danqing; Zhang, Chunhua; Ge, Ying

    2015-12-01

    The bioavailability of cadmium (Cd) to rice may be complicated by chemical and biological factors in the rhizosphere. The aim of this work is to investigate how soil iron (Fe) redox transformations and low-molecular-weight organic acid (LMWOA) exudation from root affect Cd accumulation in rice. Two soils (a paddy soil and a saline soil) with different physicochemical properties were used in this study. Soil redox conditions were changed by flooding and addition of organic matter (OM). Two days after the soil treatments, rice seedlings were transplanted in a vermiculite-soil system and grown for 10 days. We measured pH and Eh, LMWOA, Fe and Cd contents in rice, and their fractions in the soils and vermiculite. Cadmium accumulation in rice declined in both soils upon the flooding and OM treatment. Iron dissolution in the paddy soil and its deposition in the rhizosphere significantly increased upon the OM addition, but the concentration of Fe plaque on the rice root significantly declined. Conversely, although Fe transformed into less active fractions in the saline soil, Fe accumulation on the surface and in the tissue of root was considerably enhanced. The secretion of LMWOA was remarkably induced when the OM was amended in the saline soil, but the same effect was not observed in the paddy soil. Reduction of Cd uptake by rice could be attributed to different factors in the two soils. For the paddy soil, the lowered Cd bioavailability was likely due to the competition of Fe and Cd for the binding sites on the vermiculite surface. For the saline soil, however, rice responded to the low Fe mobility through more LMWOA exudation and Fe plaque formation, and their increases could explain the decrease of rice Cd. PMID:26260840

  12. Global Change Simulations Affect Potential Methane Oxidation in Upland Soils

    NASA Astrophysics Data System (ADS)

    Blankinship, J. C.; Hungate, B. A.

    2004-12-01

    decreased rates (p=0.014). These responses may be explained by improved soil aggregate stability in the first case, and reduced aggregate stability in the latter case. No effects of warming, elevated precipitation, elevated N deposition, or multifactor interactions were found. Among MCCE soils, similarly, no effects of elevated or reduced precipitation were found. While warming did not affect low elevation ecosystems, it did significantly decrease rates in the highest elevation mixed conifer forest (p=0.004). This suggests a vulnerability of cold-adapted CH4 oxidizing bacteria to elevated temperature. However, bacterial communities in all sampled ecosystems appear to be resistant to drier conditions and unaffected by wetter conditions. If biological oxidation is responsible for the current stability in atmospheric CH4 concentrations, then the improved function of this global CH4 sink is likely driven by indirect plant effects under elevated atmospheric CO2. Improved function, however, may be absent or reversed in future ecosystems that experience increased wildfire frequency and in high altitude and latitude ecosystems that experience rapid warming.

  13. Seasonal Patterns of Soil Respiration and Related Soil Biochemical Properties under Nitrogen Addition in Winter Wheat Field

    PubMed Central

    Liang, Guopeng; Houssou, Albert A.; Wu, Huijun; Cai, Dianxiong; Wu, Xueping; Gao, Lili; Li, Jing; Wang, Bisheng; Li, Shengping

    2015-01-01

    Understanding the changes of soil respiration under increasing N fertilizer in cropland ecosystems is crucial to accurately predicting global warming. This study explored seasonal variations of soil respiration and its controlling biochemical properties under a gradient of Nitrogen addition during two consecutive winter wheat growing seasons (2013–2015). N was applied at four different levels: 0, 120, 180 and 240 kg N ha-1 year-1 (denoted as N0, N12, N18 and N24, respectively). Soil respiration exhibited significant seasonal variation and was significantly affected by soil temperature with Q10 ranging from 2.04 to 2.46 and from 1.49 to 1.53 during 2013–2014 and 2014–2015 winter wheat growing season, respectively. Soil moisture had no significant effect on soil respiration during 2013–2014 winter wheat growing season but showed a significant and negative correlation with soil respiration during 2014–2015 winter wheat growing season. Soil respiration under N24 treatment was significantly higher than N0 treatment. Averaged over the two growing seasons, N12, N18 and N24 significantly increased soil respiration by 13.4, 16.4 and 25.4% compared with N0, respectively. N addition also significantly increased easily extractable glomalin-related soil protein (EEG), soil organic carbon (SOC), total N, ammonium N and nitrate N contents. In addition, soil respiration was significantly and positively correlated with β-glucosidase activity, EEG, SOC, total N, ammonium N and nitrate N contents. The results indicated that high N fertilization improved soil chemical properties, but significantly increased soil respiration. PMID:26629695

  14. Soil properties and not inputs control carbon, nitrogen, phosphorus ratios in cropped soils in the long-term

    NASA Astrophysics Data System (ADS)

    Frossard, E.; Buchmann, N.; Bünemann, E. K.; Kiba, D. I.; Lompo, F.; Oberson, A.; Tamburini, F.; Traoré, O. Y. A.

    2015-09-01

    Stoichiometric approaches have been applied to understand the relationship between soil organic matter dynamics and biological nutrient transformations. However, very few studies explicitly considered the effects of agricultural management practices on soil C : N : P ratio. The aim of this study was to assess how different input types and rates would affect the C : N : P molar ratios of bulk soil, organic matter and microbial biomass in cropped soils in the long-term. Thus, we analysed the C, N and P inputs and budgets as well as soil properties in three long-term experiments established on different soil types: the Saria soil fertility trial (Burkina Faso), the Wagga Wagga rotation/stubble management/soil preparation trial (Australia), and the DOK cropping system trial (Switzerland). In each of these trials, there was a large range of C, N and P inputs which had a strong impact on element concentrations in soils. However, although C : N : P ratios of the inputs were highly variable, they had only weak effects on soil C : N : P ratios. At Saria, a positive correlation was found between the N : P ratio of inputs and microbial biomass, while no relation was observed between the nutrient ratios of inputs and soil organic matter. At Wagga Wagga, the C : P ratio of inputs was significantly correlated to total soil C : P, N : P and C : N ratios, but had no impact on the elemental composition of microbial biomass. In the DOK trial, a positive correlation was found between the C budget and the C to organic P ratio in soils, while the nutrient ratios of inputs were not related to those in the microbial biomass. We argue that these responses are due to differences in soil properties among sites. At Saria, the soil is dominated by quartz and some kaolinite, has a coarse texture, a fragile structure and a low nutrient content. Thus, microorganisms feed on inputs (plant residues, manure). In contrast, the soil at Wagga Wagga contains illite and haematite, is richer in clay and

  15. Microbial Functional Potential and Community Composition in Permafrost-Affected Soils of the NW Canadian Arctic

    PubMed Central

    Frank-Fahle, Béatrice A.; Yergeau, Étienne; Greer, Charles W.; Lantuit, Hugues; Wagner, Dirk

    2014-01-01

    Permafrost-affected soils are among the most obvious ecosystems in which current microbial controls on organic matter decomposition are changing as a result of global warming. Warmer conditions in polygonal tundra will lead to a deepening of the seasonal active layer, provoking changes in microbial processes and possibly resulting in exacerbated carbon degradation under increasing anoxic conditions. To identify current microbial assemblages in carbon rich, water saturated permafrost environments, four polygonal tundra sites were investigated on Herschel Island and the Yukon Coast, Western Canadian Arctic. Ion Torrent sequencing of bacterial and archaeal 16S rRNA amplicons revealed the presence of all major microbial soil groups and indicated a local, vertical heterogeneity of the polygonal tundra soil community with increasing depth. Microbial diversity was found to be highest in the surface layers, decreasing towards the permafrost table. Quantitative PCR analysis of functional genes involved in carbon and nitrogen-cycling revealed a high functional potential in the surface layers, decreasing with increasing active layer depth. We observed that soil properties driving microbial diversity and functional potential varied in each study site. These results highlight the small-scale heterogeneity of geomorphologically comparable sites, greatly restricting generalizations about the fate of permafrost-affected environments in a warming Arctic. PMID:24416279

  16. Modeling the hydrologicEffects of Spatial Heterogeneity in Soil Hydraulic Properties in a Mountainous Watershed, Northwest China

    NASA Astrophysics Data System (ADS)

    He, C.; Jin, X.; Zhang, L.; Zhang, X.

    2014-12-01

    Heterogeneity of soil hydraulic properties directly affects variations of hydrological processes at corresponding scales. Understanding spatial variation of soil hydraulic properties such as soil moisture is therefore fundamental for modeling watershed ecohydrological processes. As part of the National Science Foundation of China (NSFC) funded ''Integrated Ecohydrological Research Plan of the Heihe River Watershed'', this study established an observation network that consists of sampling points, zones, and tributaries to analyze spatial variations of soil hydraulic properties in the Upper Reach of the Heihe River Watershed, a second largest inland river (terminal lake) with a drainage area of over 128,000 km2 in Northwest China. Spatial heterogeneity of soil properties was analyzed based on the large number of soil sampling and in situ observations. The spatial clustering method, Full-Order-CLK was employed to derive five soil heterogeneous zones (Configuration 97, 80, 65, 40, and 20). Subsequently, SWAT model was used to quantify the impact of the spatial heterogeneity of soil hydraulic properties on hydrologic process in the study watershed. Results show the simulations by the SWAT model with the spatially clustered soil hydraulic information from the field sampling data had much better representation of the soil heterogeneity and more accurate performance than the model using the average soil property values for each soil type derived from the coarse soil datasets (Gansu Soil Handbook at 1:1,000,000 scale). Thus, incorporating detailed field sampling soil heterogeneity data greatly improves performance in hydrologic modeling.

  17. Sampling dynamic soil properties and vegetation for soil survey and ecological site descriptions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dynamic soil property data can be collected during soil survey updates to add value to soil survey products and meet users needs for ecological site descriptions. Producers and land managers need information about soil and ecosystem change in order to plan for long-term productivity, conduct monito...

  18. Site-Specific Compaction, Soil Physical Property, and Crop Yield Relationships for Claypan Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil compaction is a concern in crop production and environmental protection. Compaction is most often quantified in the field, albeit indirectly, using cone penetrometer measurements of soil strength. The objective of this research was to relate soil compaction to soil physical properties and crop ...

  19. Guidelines for sampling for dynamic soil properties for soil survey updates

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Dynamic soil property data can be collected during soil survey updates to add value to soil survey products and meet users’ needs. Producers and land managers need information about soil and ecosystem change in order to plan for long-term productivity, conduct monitoring and assessments and predict ...

  20. Interactions of Soil Order and Land Use Management on Soil Properties in the Kukart Watershed, Kyrgyzstan

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Surveys of soil properties related to soil functioning for many regions of Kyrgyzstan are limited. This study established ranges of selected chemical [soil organic matter (SOM), pH and total N (TN)], physical (soil texture), and biochemical (six enzyme activities of C, N, P and S cycling) character...

  1. Modelling the historical changes in physical soil properties caused by wind erosion process

    NASA Astrophysics Data System (ADS)

    Lackóová, Lenka

    2016-04-01

    Soil physical properties could be significantly affected by land degradation processes. Spatial variation modelling of physical soil properties in time is important in areas where wind erosion occurs regularly. The objectives of this study were to determine the changes of spatial variability of sand, silt and clay % contents in selected area in Slovakia over 45 years using topsoil physical properties at European scale (using LUCAS topsoil) and historical Complex Soil Survey Data. The Complex Soil Survey was made in the period 1960-1970 for the whole of the Slovak Republic, using a unified methodology to build an important soil properties database including physical topsoil properties. Spatial model distribution using regression kriging algorithm created by Soil Science and Conservation Research Institute was used for comparison with LUCAS topsoil particle size distribution datasets and their derived products of clay, sand and silt % content. The results of this study will show the effects of wind erosion in long time scale. Continual total mass removal during wind erosion can produce dramatic changes in the texture of the soil surface. Fine particles are removed, which tend to concentrate sand as erosion continues. Wind erosion physically removes the most fertile portion of the soil which may lead to lower productivity or destroying the characteristics of topsoil beneficial to plant growth. Historical changes of physical soil properties are discussed in this study.

  2. Do cluster properties affect the quenching rate?

    NASA Astrophysics Data System (ADS)

    Raichoor, A.; Andreon, S.

    2014-10-01

    The quenching rate is known to depend on galaxy stellar mass and environment, however, possible dependences on the hosting halo properties, such as mass, richness, and dynamical status, are still debated. The determination of these dependences is hampered by systematics, induced by noisy estimates of cluster mass or by the lack of control on galaxy stellar mass, which may mask existing trends or introduce fake trends. We studied a sample of local clusters (20 with 0.02 < z < 0.1 and log (M200/M⊙) ≳ 14), selected independent of the galaxy properties under study, having homogeneous optical photometry and X-ray estimated properties. Using those top quality measurements of cluster mass, hence of cluster scale, richness, iron abundance, and cooling time/presence of a cool-core, we study the simultaneous dependence of quenching on these cluster properties on galaxy stellar mass M and normalised cluster-centric distance r/r200. We found that the quenching rate can be completely described by two variables only, galaxy stellar mass and normalised cluster-centric distance, and is independent of halo properties (mass, richness, iron abundance, and central cooling time/presence of a cool-core). These halo properties change, in most cases, by less than 3% the probability that a galaxy is quenched, once the mass-size (M200 - r200) scaling relation is accounted for through cluster-centric distance normalisation. Appendix A is available in electronic form at http://www.aanda.org

  3. Soil properties mapping with the DIGISOIL multi-sensor system

    NASA Astrophysics Data System (ADS)

    Grandjean, G.

    2012-04-01

    The multidisciplinary DIGISOIL project aimed to integrate and improve in situ and proximal measurement technologies for the assessment of soil properties and soil degradation indicators, going from the sensing technologies to their integration and their application in (digital) soil mapping (DSM). In order to assess and prevent soil degradation and to benefit from the different ecological, economical and historical functions of the soil in a sustainable way, high resolution and quantitative maps of soil properties are needed. The core objective of the project is to explore and exploit new capabilities of advanced geophysical technologies for answering this societal demand. To this aim, DIGISOIL addresses four issues covering technological, soil science and economic aspects: (i) the validation of geophysical (in situ, proximal and airborne) technologies and integrated pedo-geophysical inversion techniques (mechanistic data fusion) (ii) the relation between the geophysical parameters and the soil properties, (iii) the integration of the derived soil properties for mapping soil functions and soil threats, (iv) the pre-evaluation, standardisation and sub-industrialization of the proposed methodologies, including technical and economical studies related to the societal demand. With respect to these issues, the DIGISOIL project allows to develop, test and validate the most relevant geophysical technologies for mapping soil properties. The system was tested on different field tests, and validated the proposed technologies and solutions for each of the identified methods: geoelectric, GPR, EMI, seismics, magnetic and hyperspectral. After data acquisition systems, sensor geometry, and advanced data processing techniques have been developed and validated, we present now the solutions for going from geophysical data to soil properties maps. For two test sites, located respectively in Luxembourg (LU) and Mugello (IT) a set of soil properties maps have been produced. They give

  4. Disposal of olive oil mill wastes in evaporation ponds: effects on soil properties.

    PubMed

    Kavvadias, V; Doula, M K; Komnitsas, K; Liakopoulou, N

    2010-10-15

    The most common practice followed in the Med countries for the management of olive oil mill wastes (OMW) involves disposal in evaporation ponds or direct disposal on soil. So far there is lack of reliable information regarding the long-term effects of OMW application on soils. This study assesses the effects of OMW disposal in evaporation ponds on underlying soil properties in the wider disposal site as well as the impacts of untreated OMW application on agricultural soils. In case of active disposal sites, the carbonate content in most soils was decreased, whereas soil EC, as well as Cl(-), SO(4)(2-), PO(4)(3-), NH(4)(+) and particularly K(+) concentrations were substantially increased. Soil pH was only marginally affected. Phenol, total N, available P and PO(4)(3-) concentrations were considerably higher in the upper soil layers in areas adjacent to the ponds. Available B as well as DTPA extractable Cu, Mn, Zn and Fe increased substantially. Most surface soil parameters exhibited increased values at the inactive site 6 years after mill closure and cease of OMW disposal activities but differences were diminished in deeper layers. It is therefore concluded that long-term uncontrolled disposal of raw OMW on soils may affect soil properties and subsequently enhance the risk for groundwater contamination. PMID:20580156

  5. Synchrotron Microtomographic Quantification of Geometrical Soil Pore Characteristics Affected by Compaction

    NASA Astrophysics Data System (ADS)

    Udawatta, Ranjith; Gantzer, Clark; Anderson, Stephen; Assouline, Shmuel

    2015-04-01

    Soil compaction degrades soil structure and affects water, heat, and gas exchange as well as root penetration and crop production. The objective of this study was to use X-ray computed microtomography (CMT) techniques to compare differences in geometrical soil pore parameters as influenced by compaction of two different aggregate size classes. Sieved (diam. < 2mm and < 0.5mm) and repacked (1.51 and 1.72 Mg m-3) Hamra soil cores of 5- by 5-mm (average porosities were 0.44 and 0.35) were imaged at 9.6-micrometer resolution at the Argonne Advanced Photon Source (synchrotron facility) using X-ray computed microtomography. Images of 58.9 mm3 volume were analyzed using 3-Dimensional Medial Axis (3DMA) software. Geometrical characteristics of the spatial distributions of pore structures (pore radii, volume, connectivity, path length, and tortuosity) were numerically investigated. Results show that the coordination number (CN) distribution and path length (PL) measured from the medial axis were reasonably fit by exponential relationships P(CN)=10-CN/Co and P(PL)=10-PL/PLo, respectively, where Co and PLo are the corresponding characteristic constants. Compaction reduced porosity, average pore size, number of pores, and characteristic constants. The average pore radii (64 and 61 μm; p<0.04), largest pore volume (1.6 and 0.6 mm3; p=0.06), number of pores (55 and 50; p=0.09), characteristic coordination number (6.3 and 6.0; p=0.09), and characteristic path length number (116 and 105; p=0.001) were significantly greater in the low density than the high density treatment. Aggregate size also influenced measured geometrical pore parameters. This analytical technique provides a tool for assessing changes in soil pores that affect hydraulic properties and thereby provides information to assist in assessment of soil management systems.

  6. Synchrotron microtomographic quantification of geometrical soil pore characteristics affected by compaction

    NASA Astrophysics Data System (ADS)

    Udawatta, R. P.; Gantzer, C. J.; Anderson, S. H.; Assouline, S.

    2015-07-01

    Soil compaction degrades soil structure and affects water, heat, and gas exchange as well as root penetration and crop production. The objective of this study was to use X-ray computed microtomography (CMT) techniques to compare differences in geometrical soil pore parameters as influenced by compaction of two different aggregate size classes. Sieved (diam. < 2 mm and < 0.5 mm) and repacked (1.51 and 1.72 Mg m-3) Hamra soil cores of 5- by 5 mm (average porosities were 0.44 and 0.35) were imaged at 9.6-micrometer resolution at the Argonne Advanced Photon Source (synchrotron facility) using X-ray computed microtomography. Images of 58.9 mm3 volume were analyzed using 3-Dimensional Medial Axis (3DMA) software. Geometrical characteristics of the spatial distributions of pore structures (pore radii, volume, connectivity, path length, and tortuosity) were numerically investigated. Results show that the coordination number (CN) distribution and path length (PL) measured from the medial axis were reasonably fit by exponential relationships P(CN) = 10-CN/Co and P(PL) = 10-PL/PLo, respectively, where Co and PLo are the corresponding characteristic constants. Compaction reduced porosity, average pore size, number of pores, and characteristic constants. The average pore radii (63.7 and 61 μm; p < 0.04), largest pore volume (1.58 and 0.58 mm3; p = 0.06), number of pores (55 and 50; p = 0.09), characteristic coordination number (6.32 and 5.94; p = 0.09), and characteristic path length number (116 and 105; p = 0.001) were significantly greater in the low density than the high density treatment. Aggregate size also influenced measured geometrical pore parameters. This analytical technique provides a tool for assessing changes in soil pores that affect hydraulic properties and thereby provides information to assist in assessment of soil management systems.

  7. Synchrotron microtomographic quantification of geometrical soil pore characteristics affected by compaction

    NASA Astrophysics Data System (ADS)

    Udawatta, Ranjith P.; Gantzer, Clark J.; Anderson, Stephen H.; Assouline, Shmuel

    2016-05-01

    Soil compaction degrades soil structure and affects water, heat, and gas exchange as well as root penetration and crop production. The objective of this study was to use X-ray computed microtomography (CMT) techniques to compare differences in geometrical soil pore parameters as influenced by compaction of two different aggregate size classes. Sieved (diameter < 2 mm and < 0.5 mm) and repacked (1.51 and 1.72 Mg m-3) Hamra soil cores of 5 by 5 mm (average porosities were 0.44 and 0.35) were imaged at 9.6 μm resolution at the Argonne Advanced Photon Source (synchrotron facility) using X-ray CMT. Images of 58.9 mm3 volume were analyzed using 3-Dimensional Medial Axis (3-DMA) software. Geometrical characteristics of the spatial distributions of pore structures (pore radii, volume, connectivity, path length, and tortuosity) were numerically investigated. Results show that the coordination number (CN) distribution and path length (PL) measured from the medial axis were reasonably fit by exponential relationships P(CN) = 10-CN/Co and P(PL) = 10-PL/PLo, respectively, where Co and PLo are the corresponding characteristic constants. Compaction reduced porosity, average pore size, number of pores, and characteristic constants. The average pore radii (63.7 and 61 µm; p < 0.04), largest pore volume (1.58 and 0.58 mm3; p = 0.06), number of pores (55 and 50; p = 0.09), and characteristic coordination number (3.74 and 3.94; p = 0.02) were significantly different between the low-density than the high-density treatment. Aggregate size also influenced measured geometrical pore parameters. This analytical technique provides a tool for assessing changes in soil pores that affect hydraulic properties and thereby provides information to assist in assessment of soil management systems.

  8. Scaling the flood regime with the soil hydraulic properties of the catchment

    NASA Astrophysics Data System (ADS)

    Peña Rojas, Luis Eduardo; Francés García, Félix; Barrios Peña, Miguel

    2015-04-01

    The spatial land cover distribution and soil type affect the hydraulic properties of soils, facilitating or retarding the infiltration rate and the response of a catchment during flooding events. This research analyzes: 1) the effect of land cover use in different time periods as a source of annual maximum flood records nonstationarity; 2) the scalability of the relationship between soil hydraulic properties of the catchment (initial abstractions, upper soil capillary storage and vertical and horizontal hydraulic conductivity) and the flood regime. The study was conducted in Combeima River basin in Colombia - South America and it was modelled the changes in the land uses registered in 1991, 2000, 2002 and 2007, using distributed hydrological modelling and nonparametric tests. The results showed that changes in land use affect hydraulic properties of soil and it has influence on the magnitude of flood peaks. What is a new finding is that this behavior is scalable with the soil hydraulic properties of the catchment flood moments have a simple scaling behavior and the peaks flow increases with higher values of capillary soil storage, whereas higher values, the peaks decreased. Finally it was applied Generalized Extreme Values and it was found scalable behavior in the parameters of the probability distribution function. The results allowed us to find a relationship between soil hydraulic properties and the behavior of flood regime in the basin studied.

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

    PubMed

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

    2008-01-01

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

  10. First look at rock & soil properties

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The earliest survey of spectral properties of the rocks and soils surrounding Pathfinder was acquired as a narrow strip covering the region just beyond the where the rover made its egress from the lander. The wavelength filters used, all in the binocular camera's right eye, cover mainly visible wavelengths. These data reveal at least five kinds of rocks and soil in the immediate vicinity of the lander. All of the spectra are ratioed to the mean spectrum of bright red drift to highlight the differences. Different occurrences of drift (pink spectra) are closely similar. Most of the rocks (black spectra) have a dark gray color, and are both darker and less red than the drift, suggesting less weathering. Typical soils (green spectra) are intermediate in properties to the rocks and drift. Both these data and subsequent higher resolution images show that the typical soil consists of a mixture of drift and small dark gray particles resembling the rock. However, two other kinds of materials are significantly different from the rocks and drift. Pinkish or whitish pebbles and crusts on some of the rocks (blue spectra) are brighter in blue light and darker in near-infrared light than is the drift, and they lack the spectral characteristics closely associated with iron minerals. Dark red soils in the lee of several rocks are about as red as the drift, but consistently darker. The curvature in the spectrum at visible wavelengths suggests either more ferric iron minerals than in the drift or a larger particle size.

    Mars Pathfinder is the second in NASA's Discovery program of low-cost spacecraft with highly focused science goals. The Jet Propulsion Laboratory, Pasadena, CA, developed and manages the Mars Pathfinder mission for NASA's Office of Space Science, Washington, D.C. The Imager for Mars Pathfinder (IMP) was developed by the University of Arizona Lunar and Planetary Laboratory under contract to JPL. Peter Smith is the Principal Investigator. JPL is an operating division

  11. Effects of changes in land use on soil properties in Estonia

    NASA Astrophysics Data System (ADS)

    Krebstein, Kadri; Reintam, Endla

    2013-04-01

    One important factor influencing the soil properties is the human activity and especially the agricultural activity. Effects of changes in land use and human activities on soil properties are remarkable on the topsoil, the lower soil layers are less affected. During the last century the land use in Estonia has considerably changed. In Estonia the area of abandoned agricultural land has been rapidly increasing during the last decades. The purpose of our study was to estimate the effects of changes in land use on soil properties in Estonia. The field experiment has been established on the experimental station of Estonian University of Life Sciences in Rõhu. The experimental area was used during the years 1960-2006 as an apple garden, 2006-2007 it was ploughed and since 2008 the experimental area has been used as grassland. In our trial we compared the changes in soil properties before and after the experimental area was used as grassland (2007 and 2008). The two grassland species in the trial were Phalaris arundinacea L. and Dactylis glomerata L. The soil of experimental area was a sandy loam Haplic Luvisol (siltic). Soil properties like the soil bulk density, soil porosity and the water permeability were studied in 30 cm soil column in every 5 cm soil layer. The results indicated changes in the soil properties. Before the grassland management the soil bulk density was in the upper layer (0-5 cm) approximately 19 % and in deeper layer (15-20 cm) 10 % higher as under the grassland. Changes of soil porosity were not so considerable before and after the grassland management. The highest alteration occurred in the values of soil air capacity were the change was from low to high in upper layer (0-5 cm) and from medium to high in the deeper layer (15-20 cm). The water permeability before the grassland management was medium and under Dactylis glomerata in the upper layer (0-5 cm) low and in the deeper layer (15-20 cm) high. Our results showed that the vegetation provided

  12. Using the Rasch model as an objective and probabilistic technique to integrate different soil properties

    NASA Astrophysics Data System (ADS)

    Rebollo, Francisco J.; Jesús Moral García, Francisco

    2016-04-01

    Soil apparent electrical conductivity (ECa) is one of the simplest, least expensive soil measurements that integrates many soil properties affecting crop productivity, including, for instance, soil texture, water content, and cation exchange capacity. The ECa measurements obtained with a 3100 Veris sensor, operating in both shallow (0-30 cm), ECs, and deep (0-90 cm), ECd, mode, can be used as an additional and essential information to be included in a probabilistic model, the Rasch model, with the aim of quantifying the overall soil fertililty potential in an agricultural field. This quantification should integrate the main soil physical and chemical properties, with different units. In this work, the formulation of the Rasch model integrates 11 soil properties (clay, silt and sand content, organic matter -OM-, pH, total nitrogen -TN-, available phosphorus -AP- and potassium -AK-, cation exchange capacity -CEC-, ECd, and ECs) measured at 70 locations in a field. The main outputs of the model include a ranking of all soil samples according to their relative fertility potential and the unexpected behaviours of some soil samples and properties. In the case study, the considered soil variables fit the model reasonably, having an important influence on soil fertility, except pH, probably due to its homogeneity in the field. Moreover, ECd, ECs are the most influential properties on soil fertility and, on the other hand, AP and AK the less influential properties. The use of the Rasch model to estimate soil fertility potential (always in a relative way, taking into account the characteristics of the studied soil) constitutes a new application of great practical importance, enabling to rationally determine locations in a field where high soil fertility potential exists and establishing those soil samples or properties which have any anomaly; this information can be necessary to conduct site-specific treatments, leading to a more cost-effective and sustainable field

  13. Bacterial community structure and soil properties of a subarctic tundra soil in Council, Alaska

    PubMed Central

    Kim, Hye Min; Jung, Ji Young; Yergeau, Etienne; Hwang, Chung Yeon; Hinzman, Larry; Nam, Sungjin; Hong, Soon Gyu; Kim, Ok-Sun; Chun, Jongsik; Lee, Yoo Kyung

    2014-01-01

    The subarctic region is highly responsive and vulnerable to climate change. Understanding the structure of subarctic soil microbial communities is essential for predicting the response of the subarctic soil environment to climate change. To determine the composition of the bacterial community and its relationship with soil properties, we investigated the bacterial community structure and properties of surface soil from the moist acidic tussock tundra in Council, Alaska. We collected 70 soil samples with 25-m intervals between sampling points from 0–10 cm to 10–20 cm depths. The bacterial community was analyzed by pyrosequencing of 16S rRNA genes, and the following soil properties were analyzed: soil moisture content (MC), pH, total carbon (TC), total nitrogen (TN), and inorganic nitrogen ( and ). The community compositions of the two different depths showed that Alphaproteobacteria decreased with soil depth. Among the soil properties measured, soil pH was the most significant factor correlating with bacterial community in both upper and lower-layer soils. Bacterial community similarity based on jackknifed unweighted unifrac distance showed greater similarity across horizontal layers than through the vertical depth. This study showed that soil depth and pH were the most important soil properties determining bacterial community structure of the subarctic tundra soil in Council, Alaska. PMID:24893754

  14. Factors Affecting the Textural Properties of Pork

    ERIC Educational Resources Information Center

    Holmer, Sean Frederick

    2009-01-01

    Research concerning rate and extent of tenderization has focused on beef or lamb. However, it is critical to understand these processes in pork, especially as retailers move towards minimally processed or non-enhanced product. The objectives of this experiment were to evaluate the textural properties of pork (firmness and tenderness) by examining…

  15. Effects of Spatial Variability of Soil Properties on the Triggering of Rainfall-Induced Shallow Landslides

    NASA Astrophysics Data System (ADS)

    Fan, Linfeng; Lehmann, Peter; Or, Dani

    2015-04-01

    Naturally-occurring spatial variations in soil properties (e.g., soil depth, moisture, and texture) affect key hydrological processes and potentially the mechanical response of soil to hydromechanical loading (relative to the commonly-assumed uniform soil mantle). We quantified the effects of soil spatial variability on the triggering of rainfall-induced shallow landslides at the hillslope- and catchment-scales, using a physically-based landslide triggering model that considers interacting soil columns with mechanical strength thresholds (represented by the Fiber Bundle Model). The spatial variations in soil properties are represented as Gaussian random distributions and the level of variation is characterized by the coefficient of variation and correlation lengths of soil properties (i.e., soil depth, soil texture and initial water content in this study). The impacts of these spatial variations on landslide triggering characteristics were measured by comparing the times to triggering and landslide volumes for heterogeneous soil properties and homogeneous cases. Results at hillslope scale indicate that for spatial variations of an individual property (without cross correlation), the increasing of coefficient of variation introduces weak spots where mechanical damage is accelerated and leads to earlier onset of landslide triggering and smaller volumes. Increasing spatial correlation length of soil texture and initial water content also induces early landslide triggering and small released volumes due to the transition of failure mode from brittle to ductile failure. In contrast, increasing spatial correlation length of soil depth "reduces" local steepness and postpones landslide triggering. Cross-correlated soil properties generally promote landslide initiation, but depending on the internal structure of spatial distribution of each soil property, landslide triggering may be reduced. The effects of cross-correlation between initial water content and soil texture

  16. Effect of aggregation on SOC transport: linking soil properties to sediment organic matter

    NASA Astrophysics Data System (ADS)

    Kuhn, Nikolaus J.

    2016-04-01

    Soils are an interface between the Earth's spheres and shaped by the nature of the interaction between them. The relevance of soil properties for the nature of the interaction between atmosphere, hydrosphere and biosphere is well-studied and accepted, on point- or ecotone-scale. However, this understanding of the largely vertical connections between spheres is not matched by a similar recognition of soil properties affecting processes acting largely in a lateral way across the land surface, such as erosion, transport and deposition of soil and the associated organic matter. Understanding the redistribution of eroded soil organic matter falls into several disciplines, most notably soil science, agronomy, hydrology and geomorphology, and recently into biogeochemistry. Accordingly, the way soil and sediment are described differs: in soil science, aggregation and structure are essential properties, while most process-based soil erosion models treat soil as a mixture of individual mineral grains, based on concepts derived in fluvial geomorphology or civil engineering. The actual behavior of aggregated sediment and the associated organic matter is not reflected by either approach and difficult to capture due to the dynamic nature of aggregation, especially in an environment such as running water. Still, a proxy to assess the uncertainties introduced by aggregation on the behavior of soil/sediment organic while moving in water across landscapes and into the aquatic system would represent a major step forward. To develop such a proxy, a database collating relevant soil, organic matter and sediment properties could serve as an initial step to identify which soil types and erosion scenarios are prone to generate a high uncertainty compared to the use of soil texture in erosion models. Furthermore, it could serve to develop standardized analytical procedures for appropriate description of soil and organic matter as sediment.

  17. Organic and inorganic amendment application on mercury-polluted soils: effects on soil chemical and biochemical properties.

    PubMed

    García-Sánchez, Mercedes; Klouza, Martin; Holečková, Zlata; Tlustoš, Pavel; Száková, Jiřina

    2016-07-01

    On the basis of a previous study performed in our laboratory, the use of organic and inorganic amendments can significantly modify the Hg mobility in soil. We have compared the effectiveness of organic and inorganic amendments such as digestate and fly ash, respectively, reducing the Hg mobility in Chernozem and Luvisol soils differing in their physicochemical properties. Hence, the aim of this work was to compare the impact of digestate and fly ash application on the chemical and biochemical parameters in these two mercury-contaminated soils in a model batch experiment. Chernozem and Luvisol soils were artificially contaminated with Hg and then incubated under controlled conditions for 21 days. Digestate and fly ash were applied to both soils in a dose of 10 and 1.5 %, respectively, and soil samples were collected after 1, 7, 14, and 21 days of incubation. The presence of Hg in both soils negatively affected to processes such as nitrification, provoked a decline in the soil microbial biomass C (soil microbial biomass C (MBC)), and the microbial activities (arylsulfatase, and β-glucosaminidase) in both soils. Meanwhile, the digestate addition to Chernozem and Luvisol soils contaminated with Hg improved the soil chemical properties (pH, dissolved organic carbon (DOC), N (Ntot), inorganic-N forms (N-NH4 (+) and N-NO3 (-))), as consequence of high content in C and N contained in digestate. Likewise, the soil MBC and soil microbial activities (dehydrogenase, arylsulfatase, and β-glucosaminidase) were greatly enhanced by the digestate application in both soils. In contrast, fly ash application did not have a remarkable positive effect when compared to digestate in Chernozem and Luvisol soil contaminated with mercury. These results may indicate that the use of organic amendments such as digestate considerably improved the soil health in Chernozem and Luvisol compared with fly ash, alleviating the detrimental impact of Hg. Probably, the chemical properties present in

  18. Spatial variability of the properties of marsh soils and their impact on vegetation

    NASA Astrophysics Data System (ADS)

    Sidorova, V. A.; Svyatova, E. N.; Tseits, M. A.

    2015-03-01

    Spatial variability of the properties of soils and the character of vegetation was studied on seacoasts of the Velikii Island in the Kandalaksha Bay of the White Sea. It was found that the chemical and physicochemical properties of marsh soils (Tidalic Fluvisols) are largely dictated by the distance from the sea and elevation of the sampling point above sea level. The spatial distribution of the soil properties is described by a quadratic trend surface. With an increase in the distance from the sea, the concentration of ions in the soil solution decreases, and the organic carbon content and soil acidity become higher. The spatial dependence of the degree of variability in the soil properties is moderate. Regular changes in the soil properties along the sea-land gradient are accompanied by the presence of specific spatial patterns related to the system of temporary water streams, huge boulders, and beached heaps of sea algae and wood debris. The cluster analysis made it possible to distinguish between five soil classes corresponding to the following plant communities: barren surface (no permanent vegetation), clayey-sandy littoral with sparse halophytes, marsh with large rhizomatous grasses, and grass-forb-bunchberry vegetation of forest margins. The subdivision into classes is especially distinct with respect to the concentration of chloride ions. The following groups of factors affect the distribution of vegetation: the composition of the soil solution, the height above sea level, the pH of water suspensions, and the humus content.

  19. Soil property effects on wind erosion of organic soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Histosols (also known as organic soils, mucks, or peats) are soils that are dominated by organic matter (>20%) in half or more of the upper 80 cm. Forty four states have a total of 21 million ha of histosols in the United States. These soils, when intensively cropped, are subject to wind erosion r...

  20. Soil Property Effects on Wind Erosion of Organic Soils

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Histosols (also known as organic soils, mucks, or peats) are soils that are dominated by organic matter (>20%) in half or more of the upper 80 cm. Forty four states have a total of 21 million ha of histosols in the United States. These soils, when intensively cropped, are subject to wind erosion r...

  1. Trace metal distribution in pristine permafrost-affected soils of the Lena River Delta and its Hinterland, Northern Siberia, Russia

    NASA Astrophysics Data System (ADS)

    Antcibor, I.; Zubrzycki, S.; Eschenbach, A.; Kutzbach, L.; Bol'shiyanov, D.; Pfeiffer, E.-M.

    2013-02-01

    Soils are an important compartment of ecosystems and have the ability to immobilize chemicals preventing their movement to other environment compartments. Predicted climatic changes together with other anthropogenic influences on Arctic terrestrial environments may affect biogeochemical processes enhancing leaching and migration of trace elements in permafrost-affected soils. This is especially important since the Arctic ecosystems are considered to be very sensitive to climatic changes as well as to chemical contamination. This study characterizes background levels of trace metals in permafrost-affected soils of the Lena River Delta and its hinterland in northern Siberia (73.5° N-69.5° N) representing a remote region far from evident anthropogenic trace metal sources. Investigations on total element contents of iron (Fe), arsenic (As), manganese (Mn), zinc (Zn), nickel (Ni), copper (Cu), lead (Pb), cadmium (Cd), cobalt (Co) and mercury (Hg) in different soil types developed in different geological parent materials have been carried out. The highest concentrations of the majority of the measured elements were observed in soils belonging to ice-rich permafrost sediments formed during the Pleistocene (ice-complex) in the Lena River Delta region. Correlation analyses of trace metal concentrations and soil chemical and physical properties at a Holocene estuarine terrace and two modern floodplain levels in the southern-central Lena River Delta (Samoylov Island) showed that the main factors controlling the trace metal distribution in these soils are organic matter content, soil texture and contents of iron and manganese-oxides. Principal Component Analysis (PCA) revealed that soil oxides play a significant role in trace metal distribution in both top and bottom horizons. Occurrence of organic matter contributes to Cd binding in top soils and Cu binding in bottom horizons. Observed ranges of the background concentrations of the majority of trace elements were similar to

  2. Soil type as factor controlling the effects of forest transformation to agricultural use in soil aggregation and related properties

    NASA Astrophysics Data System (ADS)

    Chrenková, Katarína; Mataix-Solera, Jorge; Dlapa, Pavel; Arcenegui, Victoria

    2014-05-01

    The stability of aggregates has an important role in soil functioning and its behavior to avoid erosion and degradation, the ability to transfer liquids and gases, which are important features for crop production and ecosystem health (Tisdall and Oades, 1982). It's also a property that is highly influenced by land use and management (Angers et al., 1993). The stability of aggregates provides key information about the capacity of soil functions that defines the soil quality. This study has aimed to identify the long-term effects of forest transformation on agricultural use on soil structure and related properties. For the research was chosen seven localities in the Alicante Province (E Spain) with different soil types in all cases to compare how the land use changes can affect as a function of soil type and characteristics. In every site, samples were collected from agricultural land use (dry crops with tillage management), and in forest areas close to them with similar soil type that are used as references. On the samples, selected physical and chemical properties were analyzed such as Soil aggregate stability (AS), Organic matter (OM), Mean weight diameter (MWD) of aggregates and Water repellency (WR). As expected, in all cases the AS was significant lower in agricultural sites than in forest. But in some cases the differences were much higher than in others. In forest sites the AS varied between 46 to 82% while in agricultural sites ranged between 14 to 45%. The results showed strong positive correlation of AS with OM. The lowest initial values of AS were found in wettable sandy soils. The agricultural land use lead to relative decrease in AS by 39 to 79% compared to forest soils, indicating that some soils are much more vulnerable to land use than others. These differences can be explained mainly because intrinsic soil properties, such as OM content, texture, and WR. Particularly, the decrease in OM content and absence of WR are responsible for the decrease in

  3. Quantifying the heterogeneity of soil compaction, physical soil properties and soil moisture across multiple spatial scales

    NASA Astrophysics Data System (ADS)

    Coates, Victoria; Pattison, Ian; Sander, Graham

    2016-04-01

    England's rural landscape is dominated by pastoral agriculture, with 40% of land cover classified as either improved or semi-natural grassland according to the Land Cover Map 2007. Since the Second World War the intensification of agriculture has resulted in greater levels of soil compaction, associated with higher stocking densities in fields. Locally compaction has led to loss of soil storage and an increased in levels of ponding in fields. At the catchment scale soil compaction has been hypothesised to contribute to increased flood risk. Previous research (Pattison, 2011) on a 40km2 catchment (Dacre Beck, Lake District, UK) has shown that when soil characteristics are homogeneously parameterised in a hydrological model, downstream peak discharges can be 65% higher for a heavy compacted soil than for a lightly compacted soil. However, at the catchment scale there is likely to be a significant amount of variability in compaction levels within and between fields, due to multiple controlling factors. This research focusses in on one specific type of land use (permanent pasture with cattle grazing) and areas of activity within the field (feeding area, field gate, tree shelter, open field area). The aim was to determine if the soil characteristics and soil compaction levels are homogeneous in the four areas of the field. Also, to determine if these levels stayed the same over the course of the year, or if there were differences at the end of the dry (October) and wet (April) periods. Field experiments were conducted in the River Skell catchment, in Yorkshire, UK, which has an area of 120km2. The dynamic cone penetrometer was used to determine the structural properties of the soil, soil samples were collected to assess the bulk density, organic matter content and permeability in the laboratory and the Hydrosense II was used to determine the soil moisture content in the topsoil. Penetration results show that the tree shelter is the most compacted and the open field area

  4. On the structural factors of soil humic matter related to soil water repellence in fire-affected soils

    NASA Astrophysics Data System (ADS)

    Almendros, G.; González-Vila, F. J.; González-Pérez, J. A.; Knicker, H.; De la Rosa, J. M.; Dettweiler, C.; Hernández, Z.

    2012-04-01

    In order to elucidate the impact of forest fires on physical and chemical properties of the soils as well as on the chemical composition of the soil organic matter, samples from two Mediterranean soils with contrasted characteristics and vegetation (O horizon, Lithic Leptosols under Quercus ilex and Pinus pinaster) and one agricultural soil (Ap horizon, Luvisol) were heated at 350 °C in laboratory conditions for three successive steps up to 600 s. The C- and N-depletion in the course of the heating showed small changes up to an oxidation time of 300 s. On the other side, and after 600 s, considerable C-losses (between 21% in the Luvisol and 50% in the Leptosols) were observed. The relatively low N-depletion ca. 4% (Luvisol) and 21% (Leptosol under pine) suggested preferential loss of C and the subsequent relative enrichment of nitrogen. Paralleling the progressive depletion of organic matter, the Leptosols showed a significant increase of both pH and electrical conductivity. The former change paralleled the rapid loss of carboxyl groups, whereas the latter point to the relative enrichment of ash with a bearing on the concentration of inorganic ions, which could be considered a positive effect for the post-fire vegetation. The quantitative and qualitative analyses by solid-state 13C NMR spectra of the humic fractions in the samples subjected to successive heating times indicate significant concentration of aromatic structures newly-formed in the course of the dehydration and cyclization of carbohydrates (accumulation of black carbon-type polycyclic aromatic structures), and probably lipids and peptides. The early decarboxylation, in addition to the depletion of O-alkyl hydrophilic constituents and further accumulation of secondary aromatic structures resulted in the dramatic increase in the soil water drop penetration time. It was confirmed that this enhancement of the soil hydrophobicity is not related to an increased concentration of soil free lipid, but is

  5. City snow's physicochemical property affects snow disposal

    NASA Astrophysics Data System (ADS)

    Dovbysh, V. O.; Sharukha, A. V.; Evtin, P. V.; Vershinina, S. V.

    2015-10-01

    At the present day the industrial cities run into severe problem: fallen snow in a city it's a concentrator of pollutants and their quantity is constantly increasing by technology development. Pollution of snow increases because of emission of gases to the atmosphere by cars and factories. Large accumulation of polluted snow engenders many vexed ecological problems. That's why we need a new, non-polluting, scientifically based method of snow disposal. This paper investigates polluted snow's physicochemical property effects on snow melting. A distinctive feature of the ion accelerators with self-magnetically insulated diode is that there.

  6. Effects of Land Use and Management on Soil Hydraulic Properties

    NASA Astrophysics Data System (ADS)

    Horel, Ágota; Tóth, Eszter; Gelybó, Györgyi; Kása, Ilona; Bakacsi, Zsófia; Farkas, Csilla

    2015-11-01

    Soil hydraulic properties are among the most important parameters that determine soil quality and its capability to serve the ecosystem. Land use can significantly influence soil properties, including its hydraulic conditions; however, additional factors, such as changes in climate (temperature and precipitation), can further influence the land use effects on soil hydraulic properties. In order to develop possible adaptation measures and mitigate any negative effects of land use and climatic changes, it is important to study the impact of land use and changes in land use on soil hydraulic properties. In this paper, we summarize recent studies examining the effect of land use/land cover and the associated changes in soil hydraulic properties, mainly focusing on agricultural scenarios of cultivated croplands and different tillage systems.

  7. Transpiration affects soil CO2 production in a dry grassland

    NASA Astrophysics Data System (ADS)

    Balogh, János; Fóti, Szilvia; Pintér, Krisztina; Burri, Susanne; Eugster, Werner; Papp, Marianna; Nagy, Zoltán

    2014-05-01

    Although soil CO2 efflux can be highly variable on the diel time scale, it is often measured during daytime only. However, to get a full understanding of soil CO2 efflux and its impact on carbon cycle processes, looking at diurnal processes is crucial. Therefore, our aim was to investigate how diel variation in soil CO2 efflux from a dry, sandy grassland in Hungary depends on variations in potential drivers, such as gross primary production (GPP) and evapotranspiration (ET). In order to reach this goal, we combined measurements of CO2 and H2O fluxes by eddy covariance, soil chambers and soil CO2 gradient system. Surface CO2 fluxes were partitioned into the three CO2 production components originating from the three soil layers to clarify the timing and the source of the CO2 within the top 50 cm of the soil. CO2 production rates during the growing season were higher during nighttime than during daytime. This diel course was not only driven by soil temperature and soil moisture, but also by ET. This was shown by changes of ET causing a hysteresis loop in the diel response of CO2 production to soil temperature. CO2 production was coupled to soil temperature at night and during midday (12-14 h), when ET remained relatively constant. However, when ET was changing over time, CO2 production was decoupled from soil temperature. In order to disentangle these effects, we carried out time-lag analyses between CO2 production and efflux residuals after having subtracted the main effects of soil temperature and soil water content from measured CO2 fluxes. The results showed a strong negative correlation between ET rates and residuals of soil CO2 production, and a less strong, but still significantly time-lagged positive correlation between GPP and residuals of soil CO2 production. Thus, we could show that there is a rapid negative response of soil CO2 production rates to transpiration (suggesting CO2 transport in the xylem stream) and a delayed positive response to GPP

  8. Quantification of DOC concentrations in relation with soil properties of soils in tundra and taiga of Northern European Russia

    NASA Astrophysics Data System (ADS)

    Oosterwoud, M. R.; Temminghoff, E. J. M.; van der Zee, S. E. A. T. M.

    2010-05-01

    Potential mobilization and transport of Dissolved Organic Carbon (DOC) in subarctic river basins towards the oceans is enormous, because 23-48% of the worlds Soil Organic Carbon (SOC) is stored in northern regions. As climate changes, the amount and composition of DOC exported from these basins are expected to change. The transfer of organic carbon between soils and rivers results in fractionation of organic carbon compounds. The aim of this research is to determine the DOC concentrations, its fractions, i.e. humic (HA), fulvic (FA), and hydrophilic (HY) acids, and soil characteristics that influence the DOC sorptive properties of different soil types within a tundra and taiga catchment of Northern European Russia. DOC in taiga and tundra soil profiles (soil solution) consisted only of HY and FA, where HY became more abundant with increasing depth. Adsorption of DOC on mineral phases is the key geochemical process for release and removal of DOC from potentially soluble carbon pool. We found that adsorbed organic carbon may desorb easily and can release DOC quickly, without being dependent on mineralization and degradation. Although Extractable Organic Carbon (EOC) comprise only a small part of SOC, it is a significant buffering pool for DOC. We found that about 80-90% of released EOC was previously adsorbed. Fractionation of EOC is also influenced by the fact that predominantly HA and FA adsorbed to soil and therefore also are the main compounds released when desorbed. Flowpaths vary between taiga and tundra and through seasons, which likely affects DOC concentration found in streams. As climate changes, also flowpaths of water through soils may change, especially in tundra caused by thawing soils. Therefore, adsorptive properties of thawing soils exert a major control on DOC leaching to rivers. To better understand the process of DOC ad- and de-sorption in soils, process based soil chemical modelling, which could bring more insight in solution speciation, mineral

  9. Effects of Climate and Soil Properties on U.S. Home Lawn Soil Organic Carbon Concentration and Pool

    NASA Astrophysics Data System (ADS)

    Selhorst, Adam; Lal, Rattan

    2012-12-01

    Following turfgrass establishment, soils sequester carbon (C) over time. However, the magnitude of this sequestration may be influenced by a range of climatic and soil factors. Analysis of home lawn turfgrass soils throughout the United States indicated that both climatic and soil properties significantly affected the soil organic carbon (SOC) concentration and pool to 15-cm depth. Soil sampling showed that the mean annual temperature (MAT) was negatively correlated with SOC concentration. Additionally, a nonlinear interaction was observed between mean annual precipitation (MAP) and SOC concentration with optimal sequestration occurring in soils receiving 60-70 cm of precipitation per year. Furthermore, soil properties also influenced SOC concentration. Soil nitrogen (N) had a high positive correlation with SOC concentration, as a 0.1 % increase in N concentration led to a 0.99 % increase in SOC concentration. Additionally, soil bulk density (ρb) had a curvilinear interaction with SOC concentration, with an increase in ρb indicating a positive effect on SOC concentration until a ρb of ~1.4-1.5 Mg m-3 was attained, after which, inhibition of SOC sequestration occurred. Finally, no correlation between SOC concentration or pool was observed with texture. Based upon these results, highest SOC pools within this study are observed in regions of low MAT, moderate MAP (60-70 cm year-1), high soil N concentration, and moderate ρb (1.4-1.5 Mg m-3). In order to maximize the C storage capacity of home lawns, non C-intensive management practices should be used to maintain soils within these conditions.

  10. Predicting Soluble Nickel in Soils Using Soil Properties and Total Nickel

    PubMed Central

    Zhang, Xiaoqing; Li, Jumei; Wei, Dongpu; Li, Bo; Ma, Yibing

    2015-01-01

    Soil soluble nickel (Ni) concentration is very important for determining soil Ni toxicity. In the present study, the relationships between soil properties, total and soluble Ni concentrations in soils were developed in a wide range of soils with different properties and climate characteristics. The multiple regressions showed that soil pH and total soil Ni concentrations were the most significant parameters in predicting soluble Ni concentrations with the adjusted determination coefficients (Radj2) values of 0.75 and 0.68 for soils spiked with soluble Ni salt and the spiked soils leached with artificial rainwater to mimic field conditions, respectively. However, when the soils were divided into three categories (pH < 7, 7–8 and > 8), they obtained better predictions with Radj2 values of 0.78–0.90 and 0.79–0.94 for leached and unleached soils, respectively. Meanwhile, the other soil properties, such as amorphous Fe and Al oxides and clay, were also found to be important for determining soluble Ni concentrations, indicating that they were also presented as active adsorbent surfaces. Additionally, the whole soil speciation including bulk soil properties and total soils Ni concentrations were analyzed by mechanistic speciation models WHAM VI and Visual MINTEQ3.0. It was found that WHAM VI provided the best predictions for the soils with pH < 7, was relatively reasonable for pH 7 to 8, and gave an overestimation for pH > 8. The Visual MINTEQ3.0 could provide better estimation for pH < 8 and meanwhile quite reasonable results for pH > 8. These results indicated the possibility and applicability of these models to predict soil soluble Ni concentration by soil properties. PMID:26217951

  11. Effects of soil depth on the dynamics of selected soil properties among the highlands resources of Northeast Wollega, Ethiopia: are these sign of degradation?

    NASA Astrophysics Data System (ADS)

    Adugna, A.; Abegaz, A.

    2015-07-01

    This study was conducted with an aim to analyze the spatial variability of soil properties with depth under four prominent land use patterns viz., forestland, grazing land, cultivated land and bush land of Northeast Wollega. Soil samples were collected from the land uses at two depths (0-15 and 15-30 cm) in replicates and totally 40 composite soil samples were collected. Statistical analysis revealed significant variation in soil properties with along the selected land uses. Topsoil layer had significantly greater OM, TN, AP, sand, silt, Mg2+, K+ and Mg2+ concentrations than the subsoil layers. However, clay under all land uses and CEC under bush land and grazing land revealed reverse trends. Organic matter and CEC have stronger correlations with most of soil properties in the topsoil than in the subsoil while clay has no significant correlation with selected soil properties except with sand fraction in the sampled depths. Hence, the correlation among the selected soil properties also varies with soil depth. In general, the spatial variability of soil properties indicates that they were strongly affected by external factors (agricultural treatments and soil management practices) and internal factors (soil type and depth).

  12. Effects of Vermicompost and Water Treatment Residuals on Soil Physical Properties and Wheat Yield

    NASA Astrophysics Data System (ADS)

    Ibrahim, Mahmoud M.; Mahmoud, Essawy K.; Ibrahim, Doaa A.

    2015-04-01

    The application of vermicompost and water treatment residuals to improve the physical properties in the salt affected soils is a promising technology to meet the requirements of high plant growth and cost-effective reclamation. Therefore, the aim of this study was to investigate the effect of vermicompost and its mixtures with water treatment residuals on selected physical properties of saline sodic soil and on wheat yield. The treatments were vermicompost, water treatment residuals, vermicompost + water treatment residuals (1:1 and 2:1 wet weight ratio) at levels of 5 and 10 g dry weight kg-1 dry soil. The considered physical properties included aggregate stability, mean weight diameter, pore size distribution and dry bulk density. The addition of vermicompost and water treatment residuals had significant positive effects on the studied soil physical properties, and improved the grain yield of wheat. The treatment of (2 vermicompost + 1 water treatment residuals) at level of 5 g kg-1 soil gave the best grain yield. Combination of vermicompost and water treatment residuals improved the water treatment residuals efficiency in ameliorating the soil physical properties, and could be considered as an ameliorating material for the reclamation of salt affected soils.

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

    NASA Astrophysics Data System (ADS)

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

    2012-04-01

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

  14. 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.

  15. Geochemical composition of permafrost-affected soils around the town Tiksi, Northern Yakutia, Russia

    NASA Astrophysics Data System (ADS)

    Antcibor, Iuliia; Eschenbach, Annette; Pfeiffer, Eva-Maria

    2014-05-01

    Northeastern Siberia represents an area remote from evident anthropogenic trace metal sources. However, a risk of airborne pollution by trace metals from anthropogenic sources connected to the settlements exists. The largest of these are the settlements Tiksi (71° 42' 55.6" N, 128° 48' 46.3" E) and Kyusyur (70° 45' 41.7" N, 127° 23' 04.7" E). The area of Tiksi is located between the Lena River and the Kharaulach River mouths. It covers parts of Primorsky Ridge and Kharaulach Mountains which are a part of the Verkhoyansk Range. The objective of this study was to investigate features of the spatial element distribution in representative landscape-geochemical units of the Tiksi area and to identify whether local pollution from the settlement takes place. The physical and chemical properties of soils were accessed at three sites located radially in the immediate vicinity to the town Tiksi and one control site remote 10 km south from the settlement. The elements measured were As, Cd, Co, Cu, Fe, Mn, Ni, Pb, and Zn in soils. Differences in the element content were found for various relief forms (depressions, slopes, and elevations). The coefficient of soil buffer capacity (Bf) for the surface soil horizons in depressions was the highest (Bf > 40 %) for the majority of elements indicating their intensive accumulation there. In the surface soil horizons of elevated landscape forms the coefficient, by contrast showed low to very low soil buffer capacity to accumulate metals (0 % < Bf < 20 %). The hill slopes of the study area were characterized by moderate to high Bf (20 - 40 %) for As, Cd, Co, Cu, and Mn, low to moderate Bf (10 - 30 %) for Zn, and very low Bf (< 10 %) for elements Fe, Pb, and Ni. Based on the results, it was concluded that element properties and soil acidity together with features of topography and water drainage are likely to govern more intensive element migration to adjacent landscapes and their accumulation on acid-base barriers. No significant

  16. 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.

  17. Soil GHG emissions in a Miscanthus plantation as affected by increasing rates of biochar application.

    NASA Astrophysics Data System (ADS)

    Panzacchi, P.; Davies, C. A.; Ventura, M.; Michie, E. J.; Tonon, G.

    2012-04-01

    Biochar is defined as charcoal produced by pyrolysis with the aim to apply it to the soil in order to improve its fertility and carbon (C) storage capacity. Biochar physical and chemical properties can vary depending on the original biomass feedstock and pyrolysis conditions. The potential agricultural benefits and CO2 carbon sequestration from the application of biochar to soil, were assessed in field trials with well characterised biochar. In May 2010 we applied biochar from Miscanthus biomass produced at 450 °C at 3 different application rates: 10, 25 and 50 tons ha-1 to a 6 year old Miscanthus x giganteus plantation in Brattleby (Lincoln, UK) . Each treated 25 m2 plot had 4 replicates according to a randomised block experimental design. Biochar was incorporated to a depth of 10 cm in the soil between plant rhizomes after the harvest, through shallow tilling. CO2 emissions from biochar amended soil were monitored every two weeks by a portable infrared gas analyser (IRGA) with a closed dynamic chamber system, and continuously through 8 automated chambers (both systems from Li-COR, Lincoln, Nebraska). N2O fluxes were monitored using a closed static chamber technique with manual gas sampling and subsequent gas chromatography. Cation/anion exchange resin lysimeters were buried 20 cm deep in order to capture the leached nitrogen. Higher biochar applications led to a reduction of CO2 effluxes in the first 10 weeks of the experiment, after which no treatment effect was observed. The emission of N2O was significantly reduced in the 25 and 50 tons ha-1 application rates. Addition of biochar had no significant affect on the surface soil temperature, however the temperature sensitivity of soil respiration in the biochar treated plots decreased with increasing application rates

  18. Soil Physicochemical and Biological Properties of Paddy-Upland Rotation: A Review

    PubMed Central

    Lv, Teng-Fei; Chen, Yong; Westby, Anthony P.; Ren, Wan-Jun

    2014-01-01

    Paddy-upland rotation is an unavoidable cropping system for Asia to meet the increasing demand for food. The reduction in grain yields has increased the research interest on the soil properties of rice-based cropping systems. Paddy-upland rotation fields are unique from other wetland or upland soils, because they are associated with frequent cycling between wetting and drying under anaerobic and aerobic conditions; such rotations affect the soil C and N cycles, make the chemical speciation and biological effectiveness of soil nutrient elements varied with seasons, increase the diversity of soil organisms, and make the soil physical properties more difficult to analyze. Consequently, maintaining or improving soil quality at a desirable level has become a complicated issue. Therefore, fully understanding the soil characteristics of paddy-upland rotation is necessary for the sustainable development of the system. In this paper, we offer helpful insight into the effect of rice-upland combinations on the soil chemical, physical, and biological properties, which could provide guidance for reasonable cultivation management measures and contribute to the improvement of soil quality and crop yield. PMID:24995366

  19. Analysis of matrix effects critical to microbial transport in organic waste-affected soils across laboratory and field scales

    NASA Astrophysics Data System (ADS)

    Unc, Adrian; Goss, Michael J.; Cook, Simon; Li, Xunde; Atwill, Edward R.; Harter, Thomas

    2012-06-01

    Organic waste applications to soil (manure, various wastewaters, and biosolids) are among the most significant sources of bacterial contamination in surface and groundwater. Transport of bacteria through the vadose zone depends on flow path geometry and stability and is mitigated by interaction between soil, soil solution, air-water interfaces, and characteristics of microbial surfaces. After initial entry, the transport through soil depends on continued entrainment of bacteria and resuspension of those retained in the porous structure. We evaluated the retention of bacteria-sized artificial microspheres, varying in diameter and surface charge and applied in different suspending solutions, by a range of sieved soils contained in minicolumns, the transport of hydrophobic bacteria-sized microspheres through undisturbed soil columns as affected by waste type under simulated rainfall, and the field-scale transport of Enterococcus spp. to an unconfined sandy aquifer after the application of liquid manure. Microsphere retention reflected microsphere properties. The soil type and suspending solution affected retention of hydrophilic but not hydrophobic particles. Retention was not necessarily facilitated by manure-microsphere-soil interactions but by manure-soil interactions. Undisturbed column studies confirmed the governing role of waste type on vadose-zone microsphere transport. Filtration theory applied as an integrated analysis of transport across length scales showed that effective collision efficiency depended on the distance of travel. It followed a power law behavior with the power coefficient varying from ˜0.4 over short distances to >0.9 over 1 m (i.e., very little filtration for a finite fraction of biocolloids), consistent with reduced influence of soil solution and biocolloid properties at longer travel distances.

  20. Atmospheric Deposition of Heavy Metals in Soil Affected by Different Soil Uses of Southern Spain

    NASA Astrophysics Data System (ADS)

    Acosta, J. A.; Faz, A.; Martínez-Martínez, S.; Bech, J.

    2009-04-01

    Heavy metals are a natural constituent of rocks, sediments and soils. However, the heavy metal content of top soils is also dependent on other sources than weathering of the indigenous minerals; input from atmospheric deposition seems to be an important pathway. Atmospheric deposition is defined as the process by which atmospheric pollutants are transferred to terrestrial and aquatic surfaces and is commonly classified as either dry or wet. The interest in atmospheric deposition has increased over the past decade due to concerns about the effects of deposited materials on the environment. Dry deposition provides a significant mechanism for the removal of particles from the atmosphere and is an important pathway for the loading of heavy metals into the soil ecosystem. Within the last decade, an intensive effort has been made to determine the atmospheric heavy metal deposition in both urban and rural areas. The main objective of this study was to identification of atmospheric heavy metals deposition in soil affected by different soil uses. Study area is located in Murcia Province (southeast of Spain), in the surroundings of Murcia City. The climate is typically semiarid Mediterranean with an annual average temperature of 18°C and precipitation of 350 mm. In order to determine heavy metals atmospheric deposition a sampling at different depths (0-1 cm, 1-5 cm, 5-15 cm and 15-30 cm) was carried out in 7 sites including agricultural soils, two industrial areas and natural sites. The samples were taken to the laboratory where, dried, passed through a 2 mm sieve, and grinded. For the determination of the moisture the samples were weighed and oven dried at 105 °C for 24 h. The total amounts of metals (Pb, Cu, Pb, Zn, Cd, Mn, Ni and Cr) were determined by digesting the samples with nitric/perchoric acids and measuring with ICP-MS. Results showed that zinc contamination in some samples of industrial areas was detected, even this contamination reaches 30 cm depth; thus it is

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

    NASA Astrophysics Data System (ADS)

    Lopez, V.; Ghezzehei, T. A.

    2013-12-01

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

  2. Soil biochemical properties of grassland ecosystems under anthropogenic emission of nitrogen compounds

    NASA Astrophysics Data System (ADS)

    Kudrevatykh, Irina; Ivashchenko, Kristina; Ananyeva, Nadezhda

    2016-04-01

    Inflow of pollutants in terrestrial ecosystems nowadays increases dramatically, that might be led to disturbance of natural biogeochemical cycles and landscapes structure. Production of nitrogen fertilizers is one of the air pollution sources, namely by nitrogen compounds (NH4+, NO3-, NO2-). Air pollution by nitrogen compounds of terrestrial ecosystems might be affected on soil biochemical properties, which results increasing mineral nitrogen content in soil, changing soil P/N and Al/Ca ratios, and, finally, the deterioration of soil microbial community functioning. The research is focused on the assessment of anthropogenic emission of nitrogen compounds on soil properties of grassland ecosystems in European Russia. Soil samples (Voronic Chernozem Pachic, upper 10 cm mineral layer, totally 10) were taken from grassland ecosystem: near (5-10 m) nitrogen fertilizer factory (NFF), and far from it (20-30 km, served as a control) in Tula region. In soil samples the NH4+ and NO3- (Kudeyarov's photocolorimetric method), P, Ca, Al (X-ray fluorescence method) contents were measured. Soil microbial biomass carbon (Cmic) was analyzed by substrate-induced respiration method. Soil microbial respiration (MR) was assessed by CO2 rate production. Soil microbial metabolic quotient (qCO2) was calculated as MR/Cmic ratio. Near NFF the soil ammonium and nitrate nitrogen contents were a strongly varied, variation coefficient (CV) was 42 and 86This study was supported by Russian Foundation of Basic Research Grant No. 14-04-00098, 15-44-03220, 15-04-00915.

  3. The ash in forest fire affected soils control the soil losses. Part 1. The pioneer research

    NASA Astrophysics Data System (ADS)

    Cerdà, Artemi; Pereira, Paulo

    2013-04-01

    composition (Pereira and Úbeda, 2010) and Pereira et al., 2012). Some of the new research challenges related to ash impact in the fire affected soils are related to the ash redistribution after the fire, the impact of ash in soil and water chemistry, the temporal changes of soil erosion, the control ash exert on vegetation recovery and the role to be played by ash in the best management of fire affected land. Those topics needs new ideas and new scientists such as Paulo Pereira show in the Part II of this abstract. Acknowledgements, Lithuanian Research Council. Project LITFIRE, Fire effects on Lithuanian soils and ecosystems (MIP-48/2011) and the research projects GL2008-02879/BTE and LEDDRA 243857. References Bodí, M., Mataix-Solera, J., Doerr, S., and Cerdà, A. 2011b. The wettability of ash from burned vegetation and its relationship to Mediterranean plant species type, burn severity and total organic carbon content. Geoderma, 160, 599-607. Cerdà, A. 1998a. Postfire dynamics of erosional processes under mediterranean climatic conditions. Z. Geomorphol., 42 (3) 373-398. Cerdà, A. 1998b. Changes in overland flow and infiltration after a rangeland fire in a Mediterranean scrubland. Hydrological Processes, 12, 1031-1042. Cerdà, A., and Doerr, S. H.2010. The effect of ant mounds on overland flow and soil erodibility following a wildfire in eastern Spain. Ecohydrology, 3, 392-401. Cerdà, A., and Doerr, S.H. 2008. The effect of ash and needle cover on surface runoff and erosion in the immediate post-fire period. Catena, 74, 256-263. Pereira, P., and Úbeda, X. 2010. Spatial distribution of heavy metals released from ashes after a wildfire, Journal of Environment Engineering and Landscape Management, 18, 13-22. Pereira, P., Ubeda, X., Martin, D.A. 2012. Fire severity effects on ash chemical composition and extractable elements. Geoderma, 191, 105 - 114. Pérez-Cabello, F., Cerdà, A., de la Riva, J., Echeverría, M.T., García-Martín, A., Ibarra, P., Lasanta, T., Montorio

  4. Cadmium content of plants as affected by soil cadmium concentration

    SciTech Connect

    Lehoczky, E.; Szabados, I.; Marth, P.

    1996-12-31

    Pot experiments were conducted in greenhouse conditions to study the effects of increasing cadmium (Cd) levels on biomass production and Cd contents in corn, (Zea mays L.), garlic (Allium sativum L.), and spinach (Spinacia oleracea L.). Plants were grown in two soil types: Eutric cambisol soil and A gleyic luvisol soil. Spinach proved to be the most sensitive to Cd treatments as its biomass considerably decreased with the increasing Cd levels. Cadmium contents of the three crops increased with increasing levels of Cd applications. Statistical differences were observed in the Cd contents of crops depending on soil type. With the same Cd rates, Cd tissue concentration of test plants grown in the strongly acidic Gleyic luvisol soil were many times higher than that of plants grown in a neutral Eutric cambisol soil. 14 refs., 4 tabs.

  5. Carbon amendment and soil depth affect the distribution and abundance of denitrifiers in agricultural soils.

    PubMed

    Barrett, M; Khalil, M I; Jahangir, M M R; Lee, C; Cardenas, L M; Collins, G; Richards, K G; O'Flaherty, V

    2016-04-01

    The nitrite reductase (nirS and nirK) and nitrous oxide reductase-encoding (nosZ) genes of denitrifying populations present in an agricultural grassland soil were quantified using real-time polymerase chain reaction (PCR) assays. Samples from three separate pedological depths at the chosen site were investigated: horizon A (0-10 cm), horizon B (45-55 cm), and horizon C (120-130 cm). The effect of carbon addition (treatment 1, control; treatment 2, glucose-C; treatment 3, dissolved organic carbon (DOC)) on denitrifier gene abundance and N2O and N2 fluxes was determined. In general, denitrifier abundance correlated well with flux measurements; nirS was positively correlated with N2O, and nosZ was positively correlated with N2 (P < 0.03). Denitrifier gene copy concentrations per gram of soil (GCC) varied in response to carbon type amendment (P < 0.01). Denitrifier GCCs were high (ca. 10(7)) and the bac:nirK, bac:nirS, bac:nir (T) , and bac:nosZ ratios were low (ca. 10(-1)/10) in horizon A in all three respective treatments. Glucose-C amendment favored partial denitrification, resulting in higher nir abundance and higher N2O fluxes compared to the control. DOC amendment, by contrast, resulted in relatively higher nosZ abundance and N2 emissions, thus favoring complete denitrification. We also noted soil depth directly affected bacterial, archaeal, and denitrifier abundance, possibly due to changes in soil carbon availability with depth. PMID:26762934

  6. Response of Soil Properties and Microbial Communities to Agriculture: Implications for Primary Productivity and Soil Health Indicators.

    PubMed

    Trivedi, Pankaj; Delgado-Baquerizo, Manuel; Anderson, Ian C; Singh, Brajesh K

    2016-01-01

    Agricultural intensification is placing tremendous pressure on the soil's capacity to maintain its functions leading to large-scale ecosystem degradation and loss of productivity in the long term. Therefore, there is an urgent need to find early indicators of soil health degradation in response to agricultural management. In recent years, major advances in soil meta-genomic and spatial studies on microbial communities and community-level molecular characteristics can now be exploited as 'biomarker' indicators of ecosystem processes for monitoring and managing sustainable soil health under global change. However, a continental scale, cross biome approach assessing soil microbial communities and their functional potential to identify the unifying principles governing the susceptibility of soil biodiversity to land conversion is lacking. We conducted a meta-analysis from a dataset generated from 102 peer-reviewed publications as well as unpublished data to explore how properties directly linked to soil nutritional health (total C and N; C:N ratio), primary productivity (NPP) and microbial diversity and composition (relative abundance of major bacterial phyla determined by next generation sequencing techniques) are affected in response to agricultural management across the main biomes of Earth (arid, continental, temperate and tropical). In our analysis, we found strong statistical trends in the relative abundance of several bacterial phyla in agricultural (e.g., Actinobacteria and Chloroflexi) and natural (Acidobacteria, Proteobacteria, and Cyanobacteria) systems across all regions and these trends correlated well with many soil properties. However, main effects of agriculture on soil properties and productivity were biome-dependent. Our meta-analysis provides evidence on the predictable nature of the microbial community responses to vegetation type. This knowledge can be exploited in future for developing a new set of indicators for primary productivity and soil

  7. Parameters affecting extraction of selected fungicides from vineyard soils.

    PubMed

    Rial-Otero, Raquel; González-Rodríguez, Rosa María; Cancho-Grande, Beatriz; Simal-Gándara, Jesús

    2004-12-01

    This paper describes a sensitive method for the simultaneous quantification of eight commonly used grapevine fungicides in vineyard soils: cyprodinil, fludioxonil, metalaxyl, penconazole, pyrimethanil, procymidone, tebuconazole, and vinclozolin. The fungicides are extracted from the soil sample by sonication with water followed by shaking with ethyl acetate and are quantified by gas chromatography with mass spectrometry. Average extraction efficiencies in a sample of seven spiked, previously fungicide-free soils were > or =79% for all of the analytes, method precisions were > or =17%, and quantification limits were < or =50 microg/kg. However, because recoveries varied considerably from soil to soil, there is a need to control for soil matrix differences (mainly soil pH and exchangeable calcium content); as a consequence, soil fungicide contents must be quantified by the standard additions method. When the method was applied in this way to soil samples from vineyards belonging to the specified wine-growing region of Rias Baixas (Galicia, northwestern Spain) taken at the beginning of October (1 month after the crop's final treatment), levels of fludioxonil as high as 991 microg/kg were found, but at the start of the season (9 months after the previous crop's final treatment) only fludioxonil was detected at levels higher than its limit of quantification (45 and 52 microg/kg). PMID:15563199

  8. Greywater reuse for irrigation: effect on soil properties.

    PubMed

    Travis, Micheal J; Wiel-Shafran, Alit; Weisbrod, Noam; Adar, Eilon; Gross, Amit

    2010-05-15

    A controlled study of the effect of greywater (GW) irrigation on soil properties was conducted. Containers of sand, loam and loess soils were planted with lettuce, and irrigated with fresh water, raw artificial GW or treated artificial GW. Greywater was treated using a recirculating vertical-flow constructed wetland. Soil samples were collected every 10 days for the 40-day duration of the study, and plant growth was measured. Soils were analysed for physicochemical and biological parameters to determine changes caused by the different treatments. It was demonstrated that raw artificial GW significantly increased the development of hydrophobicity in the sand and loam soils, as determined by water droplet penetration time. No significant changes were observed for the loess soil under all treatments. Observed hydrophobicity was correlated with increased oil and grease and surfactant concentrations in the soil. Zeta (zeta) potential of the soils was measured to determine changes in the soil particle surface properties as a result of GW irrigation. A significant change in zeta-potential (less negative) was observed in the raw artificial GW-irrigated sand, whereas no difference was observed in the loam or loess. Soils irrigated with fresh water or treated GW exhibited no increase in hydrophobicity. Fecal coliform bacteria were absent or <10 CFU g(-1) in soils irrigated with fresh water or treated GW, but at least 1 order of magnitude higher in raw artificial GW irrigated soils. Only in the last sampling event and only for the loess soil was plant growth significantly higher for fresh water irrigated vs. raw or treated GW irrigated soils. This study demonstrates that treated GW can be effectively irrigated without detrimental effects on soil or plant growth; however, raw GW may significantly change soil properties that can impact the movement of water in soil and the transport of contaminants in the vadose zone. PMID:20350744

  9. Mapping soil magnetic properties in Bosnia and Herzegovina for landmine clearance operations

    NASA Astrophysics Data System (ADS)

    Hannam, J. A.; Dearing, J. A.

    2008-10-01

    Electromagnetic properties of soils have negative impacts on metal detector performance during landmine clearance operations. In particular, topsoils with high concentrations of pedogenic viscous superparamagnetic minerals (magnetite/maghemite) as shown by high values of magnetic susceptibility and frequency dependent susceptibility limit the detector capability of identifying buried landmines. Thus a priori knowledge of the spatial extent of soils that may be problematic for landmine detection would aid strategic planning of clearance operations and ensure appropriate equipment is deployed. Here, we compare two approaches for estimating the broad magnetic properties of soils in Bosnia and Herzegovina: 1) an analogue approach, using data for magnetic susceptibility and frequency dependent susceptibility available for soil types from other temperate and Mediterranean regions; 2) magnetic measurements of a stratified sample of soil samples taken from the Bosnian National Soil Archive. The national soil magnetic maps produced estimate that the area of land inferred as problematic for metal detectors is 4% and 30% according to the analogue and measurement methods respectively. Combining soil type with soil parent material and climate explains the spatial variability of soil magnetic properties in terms of mechanisms of secondary ferrimagnetic mineral production and accumulation. The resulting maps indicate that the magnetic properties of dominant soils in northern Bosnia tend to be unproblematic for detectors, while in central Bosnia there is likely to be moderate detector interference. However, there is a high likelihood of dominant soils affecting detectors in southern and western Bosnia and Herzegovina, equivalent to ~ 30% of the total land area. The mapped outputs of susceptibility and frequency dependent susceptibility provide demining end-users with an indication of the likelihood of encountering problem soils in areas selected for clearance operations.

  10. Changes in Forest Soil Properties in Different Successional Stages in Lower Tropical China

    PubMed Central

    Li, Yuelin; Yang, Fangfang; Ou, Yangxu; Zhang, Deqiang; Liu, Juxiu; Chu, Guowei; Zhang, Yaru; Otieno, Dennis; Zhou, Guoyi

    2013-01-01

    Background Natural forest succession often affects soil physical and chemical properties. Selected physical and chemical soil properties were studied in an old-growth forest across a forest successional series in Dinghushan Nature Reserve, Southern China. Methodology/Principal Findings The aim was to assess the effects of forest succession change on soil properties. Soil samples (0–20 cm depth) were collected from three forest types at different succession stages, namely pine (Pinus massoniana) forest (PMF), mixed pine and broadleaf forest (PBMF) and monsoon evergreen broadleaf forest (MEBF), representing early, middle and advanced successional stages respectively. The soil samples were analyzed for soil water storage (SWS), soil organic matter (SOM), soil microbial biomass carbon (SMBC), pH, NH4+-N, available potassium (K), available phosphorus (P) and microelements (available copper (Cu), available zinc (Zn), available iron (Fe) and available boron (B)) between 1999 and 2009. The results showed that SWS, SOM, SMBC, Cu, Zn, Fe and B concentrations were higher in the advanced successional stage (MEBF stage). Conversely, P and pH were lower in the MEBF but higher in the PMF (early successional stage). pH, NH4+-N, P and K declined while SOM, Zn, Cu, Fe and B increased with increasing forest age. Soil pH was lower than 4.5 in the three forest types, indicating that the surface soil was acidic, a stable trend in Dinghushan. Conclusion/Significance These findings demonstrated significant impacts of natural succession in an old-growth forest on the surface soil nutrient properties and organic matter. Changes in soil properties along the forest succession gradient may be a useful index for evaluating the successional stages of the subtropical forests. We caution that our inferences are drawn from a pseudo-replicated chronosequence, as true replicates were difficult to find. Further studies are needed to draw rigorous conclusions regarding on nutrient dynamics in

  11. From the study of fire effects on individual soil properties to the development of soil quality indices. 2. Application of indices

    NASA Astrophysics Data System (ADS)

    Zornoza, Raul; Mataix-Solera, Jorge

    2013-04-01

    Wildfires are one of the most serious environmental problems in the Mediterranean region. The loss of vegetation and the progressive incapability of soils to appropriately regenerate the vegetative cover have led to severe degradation. Therefore, the establishment of soil quality indices is needed at sites affected by forest fires in order to evaluate the state of degradation so that we can enhance the soil quality. The use of soil quality indices is useful since the integration of several indicators of different nature is expressed as one value, being more effective than individual soil properties for land management. Soils from natural ecosystems have specific physical, chemical and biochemical properties determined by the conditions in which these soils develop. Thus, the creation of a model that represents the established balance among different soil properties from stable forest ecosystems can be used as a soil quality index. In addition, any perturbation, such as wildfires, must lead to modifications in this natural balance. Two models with soils from five undisturbed forest regions in eastern Spain were developed, which represented the balance between organic carbon and some physical, chemical and biochemical properties (aggregate stability, water holding capacity, cation exchange capacity, available phosphorus, electrical conductivity and acid phosphatase activity). These models have been applied to soils affected by different wildfires sampled at different dates after the wildfire to evaluate how this perturbation can modify the natural balance among organic matter and different soil properties. Our results confirm that wildfires, either directly or indirectly, have provoked an imbalance among organic carbon content and physical, chemical and biochemical properties. Moreover, soils affected by recent fires showed the greatest deviation in the natural balance, indicating higher perturbation. Hence, these models (indices) are sensitive to changes provoked by

  12. ESTIMATION OF KOREAN PADDY FIELD SOIL PROPERTIES USING OPTICAL REFLECTANCE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An optical sensing approach based on diffuse reflectance has shown potential for rapid and reliable on-site estimation of soil properties. Important sensing ranges and the resulting regression models useful for soil property estimation have been reported. In this study, a similar approach was applie...

  13. Estimation of Korean paddy field soil properties using optical reflectance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An optical sensing approach based on diffuse reflectance has shown potential for rapid and reliable on-site estimation of soil properties. Important sensing ranges and the resulting regression models useful for soil property estimation have been reported. In this study, a similar approach was applie...

  14. Estimation of soil physical properties from sensor-based soil strength and apparent electrical conductivity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantification of soil physical properties has traditionally been through soil sampling and laboratory analyses, which is time-, cost-, and labor-consuming, making it difficult to obtain the spatially-dense data required for precision agriculture. Soil strength and apparent electrical conductivity (...

  15. Influence of humic acid applications on soil physicochemical properties

    NASA Astrophysics Data System (ADS)

    Gümüş, İ.; Şeker, C.

    2015-09-01

    Soil structure is often said to be the key to soil productivity since a fertile soil, with desirable soil structure and adequate moisture supply, constitutes a productive soil. Soil structure influences soil water movement and retention, erosion, crusting, nutrient recycling, root penetration and crop yield. The objective of this work is to study, humic acid (HA) application on some physical and chemical properties in weak structured soils investigated. The approach involved establishing a plot experiment in the laboratory conditions. Different rates of HA (control, 0.5, 1, 2 and 4 %) were applied to soil at three incubation periods (21, 42 and 62 days). At the end of the each incubation period, the changes in physicochemical properties were measured. Generally, HA addition increased EC values at the all incubation periods. HA applications decreased soil modulus of rupture. Application of HA at the rate of 4 % was significantly increased soil organic carbon contents. HA applications at the rate of 4 % significantly increased both mean soil total nitrogen content and aggregate stability after at three incubation periods (p < 0.05). Therefore, HA was potential to improve structure of soil in short term.

  16. Soil Tillage Management Affects Maize Grain Yield by Regulating Spatial Distribution Coordination of Roots, Soil Moisture and Nitrogen Status.

    PubMed

    Wang, Xinbing; Zhou, Baoyuan; Sun, Xuefang; Yue, Yang; Ma, Wei; Zhao, Ming

    2015-01-01

    The spatial distribution of the root system through the soil profile has an impact on moisture and nutrient uptake by plants, affecting growth and productivity. The spatial distribution of the roots, soil moisture, and fertility are affected by tillage practices. The combination of high soil density and the presence of a soil plow pan typically impede the growth of maize (Zea mays L.).We investigated the spatial distribution coordination of the root system, soil moisture, and N status in response to different soil tillage treatments (NT: no-tillage, RT: rotary-tillage, SS: subsoiling) and the subsequent impact on maize yield, and identify yield-increasing mechanisms and optimal soil tillage management practices. Field experiments were conducted on the Huang-Huai-Hai plain in China during 2011 and 2012. The SS and RT treatments significantly reduced soil bulk density in the top 0-20 cm layer of the soil profile, while SS significantly decreased soil bulk density in the 20-30 cm layer. Soil moisture in the 20-50 cm profile layer was significantly higher for the SS treatment compared to the RT and NT treatment. In the 0-20 cm topsoil layer, the NT treatment had higher soil moisture than the SS and RT treatments. Root length density of the SS treatment was significantly greater than density of the RT and NT treatments, as soil depth increased. Soil moisture was reduced in the soil profile where root concentration was high. SS had greater soil moisture depletion and a more concentration root system than RT and NT in deep soil. Our results suggest that the SS treatment improved the spatial distribution of root density, soil moisture and N states, thereby promoting the absorption of soil moisture and reducing N leaching via the root system in the 20-50 cm layer of the profile. Within the context of the SS treatment, a root architecture densely distributed deep into the soil profile, played a pivotal role in plants' ability to access nutrients and water. An optimal

  17. Soil Tillage Management Affects Maize Grain Yield by Regulating Spatial Distribution Coordination of Roots, Soil Moisture and Nitrogen Status

    PubMed Central

    Wang, Xinbing; Zhou, Baoyuan; Sun, Xuefang; Yue, Yang; Ma, Wei; Zhao, Ming

    2015-01-01

    The spatial distribution of the root system through the soil profile has an impact on moisture and nutrient uptake by plants, affecting growth and productivity. The spatial distribution of the roots, soil moisture, and fertility are affected by tillage practices. The combination of high soil density and the presence of a soil plow pan typically impede the growth of maize (Zea mays L.).We investigated the spatial distribution coordination of the root system, soil moisture, and N status in response to different soil tillage treatments (NT: no-tillage, RT: rotary-tillage, SS: subsoiling) and the subsequent impact on maize yield, and identify yield-increasing mechanisms and optimal soil tillage management practices. Field experiments were conducted on the Huang-Huai-Hai plain in China during 2011 and 2012. The SS and RT treatments significantly reduced soil bulk density in the top 0–20 cm layer of the soil profile, while SS significantly decreased soil bulk density in the 20–30 cm layer. Soil moisture in the 20–50 cm profile layer was significantly higher for the SS treatment compared to the RT and NT treatment. In the 0-20 cm topsoil layer, the NT treatment had higher soil moisture than the SS and RT treatments. Root length density of the SS treatment was significantly greater than density of the RT and NT treatments, as soil depth increased. Soil moisture was reduced in the soil profile where root concentration was high. SS had greater soil moisture depletion and a more concentration root system than RT and NT in deep soil. Our results suggest that the SS treatment improved the spatial distribution of root density, soil moisture and N states, thereby promoting the absorption of soil moisture and reducing N leaching via the root system in the 20–50 cm layer of the profile. Within the context of the SS treatment, a root architecture densely distributed deep into the soil profile, played a pivotal role in plants’ ability to access nutrients and water. An

  18. Do shrubs reduce the adverse effects of grazing on soil properties?

    USGS Publications Warehouse

    Eldridge, David J.; Beecham, Genevieve; Grace, James B.

    2015-01-01

    Increases in the density of woody plants are a global phenomenon in drylands, and large aggregations of shrubs, in particular, are regarded as being indicative of dysfunctional ecosystems. There is increasing evidence that overgrazing by livestock reduces ecosystem functions in shrublands, but that shrubs may buffer the negative effects of increasing grazing. We examined changes in water infiltration and nutrient concentrations in soils under shrubs and in their interspaces in shrublands in eastern Australia that varied in the intensity of livestock grazing. We used structural equation modelling to test whether shrubs might reduce the negative effects of overgrazing on infiltration and soil carbon and nitrogen (henceforth ‘soil nutrients’). Soils under shrubs and subject to low levels of grazing were more stable and had greater levels of soil nutrients. Shrubs had a direct positive effect on soil nutrients; but, grazing negatively affected nutrients by increasing soil bulk density. Structural equation modelling showed that shrubs had a direct positive effect on water flow under ponded conditions but also enhanced water flow, indirectly, through increased litter cover. Any positive effects of shrubs on water flow under low levels of grazing waned at high levels of grazing. Our results indicate that shrubs may reduce the adverse effects of grazing on soil properties. Specifically, shrubs could restrict access to livestock and therefore protect soils and plants beneath their canopies. Low levels of grazing are likely to ensure the retention of soil water and soil carbon and nitrogen in shrubland soils.

  19. SOIL ORGANIC MATTER AND AGGREGATE STABILITY AFFECTED BY TILLAGE IN THE NORTHERN CORN BELT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil organic matter (SOM) contains a complex pool of humic materials having important beneficial properties linked to soil function and productivity. Loss of SOM has been associated with increased tillage intensity. Objectives were to determine effect of tillage on composition of soil organic compon...

  20. The effect of soil properties on the attachment of MS2 and ØX174 to natural soils

    NASA Astrophysics Data System (ADS)

    Hiong, Florence Lee Chi; Pedley, Stephen; Charles, Katrina

    2013-04-01

    The attachment of viruses in the soil-water matrix is an important issue in environmental microbial risk assessment. The effects of different soil properties on the attachment of viruses have been studied using surrogate viruses known as bacteriophages. However, there have been few attempts to link those properties together to give an overall picture of the attachment dynamics. This study measured the attachment of bacteriophages MS2 and ØX174 to 27 natural, highly characterized soils. Statistical analysis was used to identify and rank the soil properties that facilitate virus attachment. Soil samples were mixed with artificial groundwater diluent and 1ml of bacteriophages for 3 hours. Attachment was measured by the reduction in phage titre in the supernatant (SS) relative to controls minus the soil (CS), and was presented as the ratio of SS/CS. The examined soil properties were pH, particle size distribution, moisture content, heterotrophic plate count, total nitrogen, total carbon, extractable acidity (H+) and cations (barium chloride method), and soil bulk X-ray diffraction. Spearman correlation was conducted between the SS/CS value and the tested soil properties. Where the SS/CS value was above 0.1, which showed minimum attachment of the bacteriophage to the soils, the attachment of MS2 was significantly enhanced (p<0.05) by Al (r = - 0.790) and Fe (r = - 0.573), whereas none of the tested elements could significantly enhance the attachment of ØX174. Where the SS/CS value was below 0.1, the attachment of MS2 was significantly inhibited (p<0.05) by H+ (r = 0.764), total nitrogen (r = 0.580) and total carbon (r = 0.713); whereas the attachment of ØX174 was significantly inhibited (p<0.05) only by H+ (r = 0.701).This preliminary result suggested that different bacteriophages may attach to the same soil with different efficiencies, affected by a different set of soil properties.

  1. How surface roughness affects chemical transfer from soil to surface runoff?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil surface roughness affects transport processes, e.g., runoff generation, infiltration, sediment detachment, etc., occurring on the surface. Nevertheless, how soil roughness affects chemical transport is less known. In this study, we partitioned roughness elements into mounds which diverge water ...

  2. Soil organic matter composition affected by potato cropping managements

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Organic matter is a small but important soil component. As a heterogeneous mixture of geomolecules and biomolecules, soil organic matter (SOM) can be fractionated into distinct pools with different solubility and lability. Water extractable organic matter (WEOM) fraction is the most labile and mobil...

  3. Management practices affects soil carbon dioxide emission and carbon storage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Agricultural practices contribute about 25% of total anthropogenic carbon dioxide emission, a greenhouse gas responsible for global warming. Soil can act both as sink or source of atmospheric carbon dioxide. Carbon dioxide fixed in plant biomass through photosynthesis can be stored in soil as organi...

  4. Ecosystem Warming Affects CO2 Flux in an Agricultural Soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Global warming seems likely based on present-day climate predictions. Our objective was to characterize and quantify the interactive effects of ecosystem warming (i.e., canopy temperature, TS), soil moisture content ('S) and microbial biomass (BM: bacteria, fungi) on the intra-row soil CO2 flux (FS)...

  5. How Soil Roughness Affects Runoff and Sediment Production?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effects of soil surface roughness on runoff and sediment production have not been clearly quantified, mostly due to the lack of a logical separation between geometric (i.e., surface microtopography) and process (i.e., runoff generation, soil detachment by raindrop and runoff) scales. In this resea...

  6. Effect of rock fragments on soil physical properties at pore and field scales

    NASA Astrophysics Data System (ADS)

    Gargiulo, Laura; Mele, Giacomo; Coppola, Antonio; De Mascellis, Roberto; Di Matteo, Bruno; Terribile, Fabio; Basile, Angelo

    2016-04-01

    Many soils in Mediterranean area contain high amounts of rock fragments as a result of both natural soil forming processes and human activities. Coarse rock fragments have a controversial role in soils. They are often included as a limiting factor in most Land Evaluation and Land Capability schemes throughout the world, but they also protect against soil erosion and soil physical degradation. Some experiments have showed also that, because of the beneficial effect in reducing bulk density and increasing macroporosity in topsoils, field crushing of stones could be considered a better agricultural practice than removing stones from soils. Although many experimental studies have only focused on the effect of (superficial) rock fragments on hydrological properties, direct measurements using soil image analysis allowed to improve the knowledge of the mechanisms of pore formation due to the presence of rock fragments inside the soil profile. In this work, a lab experimental test with two different soils susceptible to compaction was performed. The soils were added with different concentrations of rock fragments and subjected to several wetting/drying cycles, in order to induce formation of soil structure; then hydrological measurement and soil image analysis were performed. The measured changes in soil pore system and hydro-dispersive properties have been following implemented in simulation models in order to predict the effect of such results at field scale on yields of different crops in variable climatic conditions. Therefore, the aim of this work was to evaluate the effect at different scales (pore vs sample vs field) of rock fragment addition on many processes combining hydrological measurements with soil image analysis and modelling. The obtained results showed the usefulness of the use of image analysis to enhance the parameterization of the hydrological models and allowed to observe the role of different soil types in affecting the effect of rock fragment

  7. Towards high resolution soil property maps for Austria

    NASA Astrophysics Data System (ADS)

    Schürz, Christoph; Klotz, Daniel; Herrnegger, Mathew; Schulz, Karsten

    2015-04-01

    Soil hydraulic properties, such as soil texture, soil water retention characteristics, hydraulic conductivity, or soil depth are important inputs for hydrologic catchment modelling. However, the availability of such data in Austria is often insufficient to fulfill requirements of well-established hydrological models. Either, soil data is available in sufficient spatial resolution but only covers a small extent of the considered area, or the data is comprehensive but rather coarse in its spatial resolution. Furthermore, the level of detail and quality of the data differs between the available data sets. In order to generate a comprehensive soil data set for whole Austria that includes main soil physical properties, as well as soil depth and organic carbon content in a high spatial resolution (10x10 to 100x100m²) several available soil data bases are merged and harmonized. Starting point is a high resolution soil texture map that only covers agricultural areas and is available due to Austrian land appraisal. Soil physical properties for those areas are derived by applying pedotransfer functions (e.g. Saxton and Rawls, 2006) resulting in expectation values and quantiles of the respective property for each soil texture class. For agricultural areas where no texture information is available, the most likely soil texture is assigned applying a Bayesian network approach incorporating information such as elevation, soil slope, soil type, or hydro-geology at different spatial scales. Soil data for forested areas, that cover a large extent of the state territory, are rather sparse in Austria. For such areas a similar approach as for agricultural areas is applied by using a Bayesian network for prediction of the soil texture. Additionally, information to various soil parameters taken from literature is incorporated. For areas that are covered by land use different to agriculture or forestry, such as bare rock surfaces, or wetland areas, solely literature information is used

  8. Combined effect of soil erosion and climate change induces abrupt changes in soil and vegetation properties in semiarid Mediterranean shrublands.

    NASA Astrophysics Data System (ADS)

    Bochet, Esther; García-Fayos, Patricio

    2013-04-01

    Semiarid Mediterranean ecosystems are experiencing major alterations as a result of the complex interactions between climatic fluctuations and disturbances caused by human activities. Future scenarios of global change forecast a rapid degradation of these ecosystems, with a reduction of their functionality, as a result of changes in relevant vegetation and soil properties. Some theoretical models indicate that these ecosystems respond non-linearly to regular variations in the external conditions, with an abrupt shift when conditions approach a certain critical level or threshold. Considering these predictions, there is an urgent need to know the effects that these alterations might have on semi-arid ecosystems and their components. In this study, we aim at analyzing the consequences of climate change and increasing soil erosion on soil and vegetation properties and the functional dynamics of semiarid Mediterranean shrublands. We predict that the combined effect of both drivers will be additive or synergistic, increasing the negative effects of each one. We compared vegetation and soil properties of flat areas (low erosion) and steep hillslopes (high erosion) in two climatic areas (484 mm and 10.3°C, and 368mm and 11.9°C, respectively) that reproduce the predicted climate change in temperature and precipitation for the next 40 years. Species richness, vegetal cover, plant life-form composition were determined in 20 m2 plots and soil was sampled in the same plots to determine bulk density, aggregate stability, fertility and water holding capacity. All soil and vegetation properties were negatively affected by soil erosion and climate change. However, contrary to our hypothesis, the joined effect of both drivers on all soil and vegetation properties was antagonistic, except for the vegetal cover that showed an additive response to their interaction. Our results evidence that soil erosion affects more negatively the soil and vegetation properties in the cooler and

  9. Evolution of black carbon properties in soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Black carbon deposited in soil from natural or deliberate wildfires and engineered black carbon products (biochar) intentionally added to soil are known to have significant effects on soil biogeochemical processes and in many cases to influence the yield and quality of crops and to enhance the abili...

  10. Degradation of Herbicide Mesotrione in Three Soils with Differing Physicochemical Properties from China.

    PubMed

    Quan, Guixiang; Yin, Chuntao; Chen, Tianming; Yan, Jinlong

    2015-09-01

    The movement and fate of herbicides in soils under various environmental factors are important in evaluating their mobility and ecological impact. The effects of sterilization, solarization, and soil physicochemical properties on the degradation of herbicide mesotrione in three soils from China were evaluated using laboratory incubation method, and the degradation kinetics were also simulated using pseudo first-order reaction model. The calculated half-lives () of mesotrione were found to be 3.78- to 5.24-fold increased in sterilized soils than nonsterilized soils, which indicated that the degradation of mesotrione was strongly affected by soil microbial activity. A certain role of promoting degradation effect of natural light was found, and the values appeared to be only 7.90, 15.89, and 25.29 d in the surface of paddy soil, sandy loess, and silt clay loam, respectively. Correlation analysis between the observed first-order reaction rate constant () values and the selected soil properties revealed that the degradation of mesotrione was highly dependent on soil pH value ( > 0.992) and organic matter content ( > 0.932), but less related with clay content (<0.02 mm) with < 0.761 and nonrelated with cation exchange capacity (CEC) ( < 0.164). Data obtained in this study are helpful for further research on the prediction of the movement and fate of mesotrione in soils in limiting its environmental impact. PMID:26436279

  11. Moderately haloalkaliphilic actinomycetes in salt-affected soils

    NASA Astrophysics Data System (ADS)

    Zvyagintsev, D. G.; Zenova, G. M.; Oborotov, G. V.

    2009-12-01

    It was found that the population density of actinomycetes in solonchaks and saline desert soils varied from hundreds to tens of thousands of colony-forming units (CFUs) per 1 g of soil depending on soil type and was by 1-3 orders of magnitude lower than the number of mycelial bacteria in main soil types. Actinomycetes grow actively in saline soils, and the length of their mycelium reaches 140 m per 1 g of soil. Domination of moderately halophilic, alkaliphilic, and haloalkaliphilic actinomycetes, which grow well under 5% NaCl and pH 8-9, is a specific feature of actinomycetal complexes in saline soils. Representatives of Streptomyces and Micromonospora genera were found among the haloalkaliphilic actinomycetes. Micromonospores demonstrated lower (than streptomycetes) adaptability to high salt concentrations. Investigation of the phylogenetic position of isolated dominant haloalkaliphilic strains of streptomycetes performed on the basis of sequencing of the gene 16S rRNA enabled identifying these strains as Streptomyces pluricolorescens and S. prunicolor.

  12. A global data set of soil particle size properties

    NASA Technical Reports Server (NTRS)

    Webb, Robert S.; Rosenzweig, Cynthia E.; Levine, Elissa R.

    1991-01-01

    A standardized global data set of soil horizon thicknesses and textures (particle size distributions) was compiled. This data set will be used by the improved ground hydrology parameterization designed for the Goddard Institute for Space Studies General Circulation Model (GISS GCM) Model 3. The data set specifies the top and bottom depths and the percent abundance of sand, silt, and clay of individual soil horizons in each of the 106 soil types cataloged for nine continental divisions. When combined with the World Soil Data File, the result is a global data set of variations in physical properties throughout the soil profile. These properties are important in the determination of water storage in individual soil horizons and exchange of water with the lower atmosphere. The incorporation of this data set into the GISS GCM should improve model performance by including more realistic variability in land-surface properties.

  13. Variability of the soil-to-plant radiocaesium transfer factor for Japanese soils predicted with soil and plant properties.

    PubMed

    Uematsu, Shinichiro; Vandenhove, Hildegarde; Sweeck, Lieve; Van Hees, May; Wannijn, Jean; Smolders, Erik

    2016-03-01

    Food chain contamination with radiocaesium (RCs) in the aftermath of the Fukushima accident calls for an analysis of the specific factors that control the RCs transfer. Here, soil-to-plant transfer factors (TF) of RCs for grass were predicted from the potassium concentration in soil solution (mK) and the Radiocaesium Interception Potential (RIP) of the soil using existing mechanistic models. The mK and RIP were (a) either measured for 37 topsoils collected from the Fukushima accident affected area or (b) predicted from the soil clay content and the soil exchangeable potassium content using the models that had been calibrated for European soils. An average ammonium concentration was used throughout in the prediction. The measured RIP ranged 14-fold and measured mK varied 37-fold among the soils. The measured RIP was lower than the RIP predicted from the soil clay content likely due to the lower content of weathered micas in the clay fraction of Japanese soils. Also the measured mK was lower than that predicted. As a result, the predicted TFs relying on the measured RIP and mK were, on average, about 22-fold larger than the TFs predicted using the European calibrated models. The geometric mean of the measured TFs for grass in the affected area (N = 82) was in the middle of both. The TFs were poorly related to soil classification classes, likely because soil fertility (mK) was obscuring the effects of the soil classification related to the soil mineralogy (RIP). This study suggests that, on average, Japanese soils are more vulnerable than European soils at equal soil clay and exchangeable K content. The affected regions will be targeted for refined model validation. PMID:26717351

  14. Response of Soil Properties and Microbial Communities to Agriculture: Implications for Primary Productivity and Soil Health Indicators

    PubMed Central

    Trivedi, Pankaj; Delgado-Baquerizo, Manuel; Anderson, Ian C.; Singh, Brajesh K.

    2016-01-01

    Agricultural intensification is placing tremendous pressure on the soil’s capacity to maintain its functions leading to large-scale ecosystem degradation and loss of productivity in the long term. Therefore, there is an urgent need to find early indicators of soil health degradation in response to agricultural management. In recent years, major advances in soil meta-genomic and spatial studies on microbial communities and community-level molecular characteristics can now be exploited as ‘biomarker’ indicators of ecosystem processes for monitoring and managing sustainable soil health under global change. However, a continental scale, cross biome approach assessing soil microbial communities and their functional potential to identify the unifying principles governing the susceptibility of soil biodiversity to land conversion is lacking. We conducted a meta-analysis from a dataset generated from 102 peer-reviewed publications as well as unpublished data to explore how properties directly linked to soil nutritional health (total C and N; C:N ratio), primary productivity (NPP) and microbial diversity and composition (relative abundance of major bacterial phyla determined by next generation sequencing techniques) are affected in response to agricultural management across the main biomes of Earth (arid, continental, temperate and tropical). In our analysis, we found strong statistical trends in the relative abundance of several bacterial phyla in agricultural (e.g., Actinobacteria and Chloroflexi) and natural (Acidobacteria, Proteobacteria, and Cyanobacteria) systems across all regions and these trends correlated well with many soil properties. However, main effects of agriculture on soil properties and productivity were biome-dependent. Our meta-analysis provides evidence on the predictable nature of the microbial community responses to vegetation type. This knowledge can be exploited in future for developing a new set of indicators for primary productivity and

  15. Effect of Combustion Temperature on Soil and Soil Organic Matter Properties: A Study of Soils from the Western Elevation Transect in Central Sierra Nevada, California

    NASA Astrophysics Data System (ADS)

    Araya, S. N.; Berhe, A. A.

    2014-12-01

    Fire is a common ecosystem perturbation that affects many soil physical and chemical properties and soil organic matter (SOM). We investigated the effect of combustion temperatures on the physical and chemical properties of five soils from an elevation transect that spans from 210 to 2865 m.a.s.l. along the Western slope of the Sierra Nevada. All soils formed on a granitic parent material under either oak woodland, oak/mixed-conifer forest, mixed-conifer forest or subalpine mixed-conifer forest ecosystem. Soils show significant differences in SOM content and mineralogy owing to the effects of climate on soil development. Soils from 0 to 5 cm depth were combusted in a muffle furnace at six different temperatures within major fire intensity classes (150, 250, 350, 450, 550 and 650ºC). We determined the effects of combustion temperature on aggregation; specific surface area; pH; mineralogy; cation exchange capacity; carbon (C) and nitrogen (N) content; 13C and 15N isotopic composition, and distribution within aggregate sizes; and quality of SOM through infrared spectroscopy. Among other things, we found significant reduction total C and N, accumulation of aromatic carbon functional groups, and loss of aggregation with implication to loss of protection of C as the combustion temperature increases. The findings demonstrate that most significant changes in the soils physical and chemical properties occur around 350ºC. Findings from this study are critical for estimating the amount and rate of change in C and N loss, and other essential soil properties that can be expected from topsoils exposed to different intensity fires.

  16. Does management intensity in inter rows effect soil physical properties in Austrian and Romanian vineyards?

    NASA Astrophysics Data System (ADS)

    Bauer, Thomas; Strauss, Peter; Stiper, Katrin; Klipa, Vladimir; Popescu, Daniela; Winter, Silvia; Zaller, Johann G.

    2016-04-01

    Successful viticulture is mainly influenced by soil and climate. The availability of water during the growing season highly influences wine quality and quantity. To protect soil from being eroded most of the winegrowers keep the inter row zones of the vineyards green. Greening also helps to provide water-stress to the grapes for harvesting high quality wines. However, these greening strategies concerning the intensity of inter row management differ from farm to farm and are mainly based on personal experience of the winegrowers. However to what extent different inter row management practices affect soil physical properties are not clearly understood yet. To measure possible effects of inter row management in vineyards on soil physical parameters we selected paired vineyards with different inter row management in Austria and Romania. In total more than 7000 soil analysis were conducted for saturated and unsaturated hydraulic conductivity, soil water retention, water stable aggregates, total organic carbon, cation exchange capacity, potassium, phosphorous, soil texture, bulk density and water infiltration. The comparison between high intensity management with at least one soil disturbance per year, medium intensity with one soil disturbance every second inter row per year and low intensity management with no soil disturbance since at least 5 years indicates that investigated soil physical properties did not improve for the upper soil layer (3-8cm). This is in contrast to general perceptions of improved soil physical properties due to low intensity of inter row management, i.e. permanent vegetated inter rows. This may be attributed to long term and high frequency mechanical stress by agricultural machinery in inter rows.

  17. Evaluating the contribution of soil properties to modifying lead phytoavailability and phytotoxicity.

    PubMed

    Dayton, Elizabeth A; Basta, Nicholas T; Payton, Mark E; Bradham, Karen D; Schroder, Jackie L; Lanno, Roman P

    2006-03-01

    Soil properties affect Pb bioavailability to human and ecological receptors and should be considered during ecological risk assessment of contaminated soil. We used path analysis (PA) to determine the relative contribution of soil properties (pH, organic C [OC], amorphous Fe and Al oxides [FEAL], and cation-exchange capacity [CEC]) in modifying Pb bioavailability. The response of biological endpoints (bioaccumulation and dry matter growth [DMG]) of lettuce (Lactuca sativa) grown on 21 Pb-spiked (2,000 mg/kg) soils were determined. Lettuce tissue Pb ranged from 3.22 to 233 mg/kg, and relative DMG ranged from 2.5 to 88.5% of their respective controls. Simple correlation showed strong relationships between CEC and OC (p < 0.01) and weaker relationships between pH and FEAL (p < 0.05) and Pb bioaccumulation. Results of PA suggest that soil pH increased the negative surface charge of organic matter and clay, thereby increasing CEC and decreasing Pb bioaccumulation. Also, the direct effect of OC on tissue Pb can be attributed to formation of surface Pb complexes by organic matter functional group ligands. Increased OC and/or CEC reduced Pb solubility and bioavailability in the 21 soils in the present study. The relative importance of soil properties likely will vary between studies employing different soils. Soil properties should be considered during the ecological risk assessment of metal in contaminated soils. Path analysis is useful for ecological studies involving soils with a wide range of physicochemical properties and can assist in site risk assessment of metals and remediation decisions on contaminated sites. PMID:16566156

  18. SAMPLING AND CALIBRATION REQUIREMENTS FOR OPTICAL REFLECTANCE SOIL PROPERTY SENSORS FOR KOREAN PADDY SOILS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Optical diffuse reflectance sensing has potential for rapid and reliable on-site estimation of soil properties. For good results, proper calibration to measured soil properties is required. One issue is whether it is necessary to develop calibrations using samples from the specific area or areas (e....

  19. Biotic and Abiotic Soil Properties Influence Survival of Listeria monocytogenes in Soil

    PubMed Central

    Locatelli, Aude; Spor, Aymé; Jolivet, Claudy; Piveteau, Pascal; Hartmann, Alain

    2013-01-01

    Listeria monocytogenes is a food-borne pathogen responsible for the potentially fatal disease listeriosis and terrestrial ecosystems have been hypothesized to be its natural reservoir. Therefore, identifying the key edaphic factors that influence its survival in soil is critical. We measured the survival of L. monocytogenes in a set of 100 soil samples belonging to the French Soil Quality Monitoring Network. This soil collection is meant to be representative of the pedology and land use of the whole French territory. The population of L. monocytogenes in inoculated microcosms was enumerated by plate count after 7, 14 and 84 days of incubation. Analysis of survival profiles showed that L. monocytogenes was able to survive up to 84 days in 71% of the soils tested, in the other soils (29%) only a short-term survival (up to 7 to 14 days) was observed. Using variance partitioning techniques, we showed that about 65% of the short-term survival ratio of L. monocytogenes in soils was explained by the soil chemical properties, amongst which the basic cation saturation ratio seems to be the main driver. On the other hand, while explaining a lower amount of survival ratio variance (11%), soil texture and especially clay content was the main driver of long-term survival of L. monocytogenes in soils. In order to assess the effect of the endogenous soils microbiota on L. monocytogenes survival, sterilized versus non-sterilized soils microcosms were compared in a subset of 9 soils. We found that the endogenous soil microbiota could limit L. monocytogenes survival especially when soil pH was greater than 7, whereas in acidic soils, survival ratios in sterilized and unsterilized microcosms were not statistically different. These results point out the critical role played by both the endogenous microbiota and the soil physic-chemical properties in determining the survival of L. monocytogenes in soils. PMID:24116083

  20. Effect of soil properties, heavy metals and emerging contaminants in the soil nematodes diversity.

    PubMed

    Gutiérrez, Carmen; Fernández, Carlos; Escuer, Miguel; Campos-Herrera, Raquel; Beltrán Rodríguez, M Eulalia; Carbonell, Gregoria; Rodríguez Martín, Jose Antonio

    2016-06-01

    Among soil organisms, nematodes are seen as the most promising candidates for bioindications of soil health. We hypothesized that the soil nematode community structure would differ in three land use areas (agricultural, forest and industrial soils), be modulated by soil parameters (N, P, K, pH, SOM, CaCO3, granulometric fraction, etc.), and strongly affected by high levels of heavy metals (Cd, Pb, Zn, Cr, Ni, Cu, and Hg) and emerging contaminants (pharmaceuticals and personal care products, PPCPs). Although these pollutants did not significantly affect the total number of free-living nematodes, diversity and structure community indices vastly altered. Our data showed that whereas nematodes with r-strategy were tolerant, genera with k-strategy were negatively affected by the selected pollutants. These effects diminished in soils with high levels of heavy metals given their adaptation to the historical pollution in this area, but not to emerging pollutants like PPCPs. PMID:26895540

  1. Effects of soil properties on copper toxicity to earthworm Eisenia fetida in 15 Chinese soils.

    PubMed

    Duan, Xiongwei; Xu, Meng; Zhou, Youya; Yan, Zengguang; Du, Yanli; Zhang, Lu; Zhang, Chaoyan; Bai, Liping; Nie, Jing; Chen, Guikui; Li, Fasheng

    2016-02-01

    The bioavailability and toxicity of metals in soil are influenced by a variety of soil properties, and this principle should be recognized in establishing soil environmental quality criteria. In the present study, the uptake and toxicity of Cu to the earthworm Eisenia fetida in 15 Chinese soils with various soil properties were investigated, and regression models for predicting Cu toxicity across soils were developed. The results showed that earthworm survival and body weight change were less sensitive to Cu than earthworm cocoon production. The soil Cu-based median effective concentrations (EC50s) for earthworm cocoon production varied from 27.7 to 383.7 mg kg(-1) among 15 Chinese soils, representing approximately 14-fold variation. Soil cation exchange capacity and organic carbon content were identified as key factors controlling Cu toxicity to earthworm cocoon production, and simple and multiple regression models were developed for predicting Cu toxicity across soils. Tissue Cu-based EC50s for earthworm cocoon production were also calculated and varied from 15.5 to 62.5 mg kg(-1) (4-fold variation). Compared to the soil Cu-based EC50s for cocoon production, the tissue Cu-based EC50s had less variation among soils, indicating that metals in tissue were more relevant to toxicity than metals in soil and hence represented better measurements of bioavailability. PMID:26688255

  2. Mycelial actinobacteria in salt-affected soils of arid territories of Ukraine and Russia

    NASA Astrophysics Data System (ADS)

    Grishko, V. N.; Syshchikova, O. V.; Zenova, G. M.; Kozhevin, P. A.; Dubrova, M. S.; Lubsanova, D. A.; Chernov, I. Yu.

    2015-01-01

    A high population density (up to hundreds of thousands or millions CFU/g soil) of mycelial bacteria (actinomycetes) is determined in salt-affected soils of arid territories of Ukraine, Russia, and Turkmenistan. Of all the studied soils, the lowest amounts of actinomycetes (thousands and tens of thousands CFU/g soil) are isolated from sor (playa) and soda solonchaks developed on the bottoms of drying salt lakes in Buryatia and in the Amu Darya Delta. Actinomycetes of the Streptomyces, Micromonospora, and Nocardiopsis genera were recorded in the studied soils. It is found that conditions of preincubation greatly affect the activity of substrate consumption by the cultures of actinomycetes. This could be attributed to changes in the metabolism of actinomycetes as a mechanism of their adaptation to the increased osmotic pressure of the medium. The alkali tolerance of halotolerant actinomycetes isolated from the salt-affected soils is experimentally proved.

  3. Land use type significantly affects microbial gene transcription in soil.

    PubMed

    Nacke, Heiko; Fischer, Christiane; Thürmer, Andrea; Meinicke, Peter; Daniel, Rolf

    2014-05-01

    Soil microorganisms play an essential role in sustaining biogeochemical processes and cycling of nutrients across different land use types. To gain insights into microbial gene transcription in forest and grassland soil, we isolated mRNA from 32 sampling sites. After sequencing of generated complementary DNA (cDNA), a total of 5,824,229 sequences could be further analyzed. We were able to assign nonribosomal cDNA sequences to all three domains of life. A dominance of bacterial sequences, which were affiliated to 25 different phyla, was found. Bacterial groups capable of aromatic compound degradation such as Phenylobacterium and Burkholderia were detected in significantly higher relative abundance in forest soil than in grassland soil. Accordingly, KEGG pathway categories related to degradation of aromatic ring-containing molecules (e.g., benzoate degradation) were identified in high abundance within forest soil-derived metatranscriptomic datasets. The impact of land use type forest on community composition and activity is evidently to a high degree caused by the presence of wood breakdown products. Correspondingly, bacterial groups known to be involved in lignin degradation and containing ligninolytic genes such as Burkholderia, Bradyrhizobium, and Azospirillum exhibited increased transcriptional activity in forest soil. Higher solar radiation in grassland presumably induced increased transcription of photosynthesis-related genes within this land use type. This is in accordance with high abundance of photosynthetic organisms and plant-infecting viruses in grassland. PMID:24553913

  4. Soil Property Influences on Xiphinema americanum Populations as Related to Maturity of Loess-Derived Soils

    PubMed Central

    Schmitt, D. P.

    1973-01-01

    Field populations of Xiphinerna americanum around roots of Syringa vulgaris 'President Lincoln' were larger in Marshall silty clay loam, a medially developed loess soil, than in Monona silt loam, a minimally developed loess soil. Most X. amerieanum occurred in the top 15 cm of soil, with few below 30 cm. Maximum numbers occurred in August of both years in the Marshall soil, and in August 1969 and June 1970 in the Monona soil. Population fluctuations during the growing season were coincident with changes in soil moisture content. Although the population fluctuation pattern was the same at each depth tested, the adult-to-juvenile ratio increased in one soil while it decreased in the other. Numbers of X. americanum decreased as root weights decreased within a soil profile, but they were not correlated with root weights over all soils and depths. More X. americanum were recovered from the Marshall than from the Monona soil, but fibrous root weights were greater in the Monona soil. Survival of X. americanum in soil columns in growth chamber experiments was better in the Marshall than in the Monona soil. Movement and survival were different in identically textured Monona A and B horizon soils. Factors related to the ion exchange sites may affect X. americanum. PMID:19319342

  5. Soil Property Influences on Xiphinema americanum Populations as Related to Maturity of Loess-Derived Soils.

    PubMed

    Schmitt, D P

    1973-10-01

    Field populations of Xiphinerna americanum around roots of Syringa vulgaris 'President Lincoln' were larger in Marshall silty clay loam, a medially developed loess soil, than in Monona silt loam, a minimally developed loess soil. Most X. amerieanum occurred in the top 15 cm of soil, with few below 30 cm. Maximum numbers occurred in August of both years in the Marshall soil, and in August 1969 and June 1970 in the Monona soil. Population fluctuations during the growing season were coincident with changes in soil moisture content. Although the population fluctuation pattern was the same at each depth tested, the adult-to-juvenile ratio increased in one soil while it decreased in the other. Numbers of X. americanum decreased as root weights decreased within a soil profile, but they were not correlated with root weights over all soils and depths. More X. americanum were recovered from the Marshall than from the Monona soil, but fibrous root weights were greater in the Monona soil. Survival of X. americanum in soil columns in growth chamber experiments was better in the Marshall than in the Monona soil. Movement and survival were different in identically textured Monona A and B horizon soils. Factors related to the ion exchange sites may affect X. americanum. PMID:19319342

  6. The levels and composition of persistent organic pollutants in alluvial agriculture soils affected by flooding.

    PubMed

    Maliszewska-Kordybach, Barbara; Smreczak, Bozena; Klimkowicz-Pawlas, Agnieszka

    2013-12-01

    The concentrations and composition of persistent organic pollutants (POPs) were determined in alluvial soils subjected to heavy flooding in a rural region of Poland. Soil samples (n = 30) were collected from the upper soil layer from a 70-km(2) area. Chemical determinations included basic physicochemical properties and the contents of polychlorinated biphenyls (PCBs), hexachlorocyclohexanes (HCHs), dichlorodiphenyltrichloroethanes (DDTs) and polycyclic aromatic hydrocarbons (PAHs, 16 compounds). The median concentrations of Σ7PCB (PCB28 + PCB52 + PCB101 + PCB118 + PCB138 + PCB153 + PCB180), Σ3HCH (α-HCH + β-HCH + γ-HCH) and Σ3pp'(DDT + DDE + DDD) were 1.60 ± 1.03, 0.22 ± 0.13 and 25.18 ± 82.70 μg kg(-1), respectively. The median concentrations of the most abundant PAHs, phenanthrene, fluoranthene, pyrene, benzo[b]fluoranthene and benzo[a]pyrene were 50 ± 37, 38 ± 27, 29 ± 30, 45 ± 36 and 24 ± 22 μg kg(-1), respectively. Compared with elsewhere in the world, the overall level of contamination with POPs was low and similar to the levels in agricultural soils from neighbouring countries, except for benzo[a]pyrene and DDT. There was no evidence that flooding affected the levels of POPs in the studied soils. The patterns observed for PAHs and PCBs indicate that atmospheric deposition is the most important long-term source of these contaminants. DDTs were the dominant organochlorine pesticides (up to 99%), and the contribution of the parent pp' isomer was up to 50 % of the ΣDDT, which indicates the advantage of aged contamination. A high pp'DDE/pp'DDD ratio suggests the prevalence of aerobic transformations of parent DDT. Dominance of the γ isomer in the HCHs implies historical use of lindane in the area. The effect of soil properties on the POP concentrations was rather weak, although statistically significant links with the content of the <0.02-mm fraction, Ctotal or Ntotal were observed for some individual compounds in the PCB group. PMID:23877573

  7. Hygrothermal Simulation of Foundations: Part 1 - Soil Material Properties

    SciTech Connect

    Kehrer, Manfred; Pallin, Simon B

    2012-10-01

    The hygrothermal performance of soils coupled to buildings is a complicated process. A computational approach for heat transfer through the ground has been well defined (EN ISO 13370:2007, 2007), and simplified methods have been developed (Staszczuk, Radon, and Holm 2010). However, these approaches generally ignore the transfer of soil moisture, which is not negligible (Janssen, Carmeliet, and Hens 2004). This study is divided into several parts. The intention of the first part is to gather, comprehend and adapt soil properties from Soil Science. The obtained information must be applicable to related tasks in Building Science and validated with hygrothermal calculation tools. Future parts of this study will focus on the validation aspect of the soil properties to be implemented. Basic changes in the software code may be requested at this time. Different types of basement construction will be created with a hygrothermal calculation tool, WUFI. Simulations from WUFI will be compared with existing or ongoing measurements. The intentions of the first part of this study have been fulfilled. The soil properties of interest in Building Science have been defined for 12 different soil textures. These properties will serve as input parameters when performing hygrothermal calculations of building constructions coupled to soil materials. The reliability of the soil parameters will be further evaluated with measurements in Part 2.

  8. Soil-aquifer phenomena affecting groundwater under vertisols: a review

    NASA Astrophysics Data System (ADS)

    Kurtzman, D.; Baram, S.; Dahan, O.

    2015-09-01

    Vertisols are cracking clayey soils that: (i) usually form in alluvial lowlands where normally, groundwater pools into aquifers, (ii) have different types of voids (due to cracking) which make flow and transport of water, solutes and gas complex, and (iii) are regarded as fertile soils in many areas. The combination of these characteristics results in the unique soil-aquifer phenomena that are highlighted and summarized in this review. The review is divided into the following four sections: (1) soil cracks as preferential pathways for water and contaminants; in this section lysimeter- to basin-scale observations that show the significance of cracks as preferential flow paths in vertisols which bypass matrix blocks in the unsaturated zone are summarized. Relatively fresh-water recharge and groundwater contamination from these fluxes and their modeling are reviewed, (2) soil cracks as deep evaporators and unsaturated-zone salinity; deep sediment samples under uncultivated vertisols in semiarid regions reveal a dry (immobile), saline matrix, partly due to enhanced evaporation through soil cracks. Observations of this phenomenon are compiled in this section and the mechanism of evapoconcentration due to air flow in the cracks is discussed, (3) impact of cultivation on flushing of the unsaturated zone and aquifer salinization; the third section examines studies reporting that land-use change of vertisols from native land to cropland promotes greater fluxes through the saline unsaturated-zone matrix, eventually flushing salts to the aquifer. Different degrees of salt flushing are assessed as well as aquifer salinization on different scales, and a comparison is made with aquifers under other soils, (4) relatively little nitrate contamination in aquifers under vertisols; In this section we turn the light on observations showing that aquifers under cultivated vertisols are somewhat resistant to groundwater contamination by nitrate (the major agriculturally related

  9. Soil-aquifer phenomena affecting groundwater under vertisols: a review

    NASA Astrophysics Data System (ADS)

    Kurtzman, D.; Baram, S.; Dahan, O.

    2016-01-01

    Vertisols are cracking clayey soils that (i) usually form in alluvial lowlands where, normally, groundwater pools into aquifers; (ii) have different types of voids (due to cracking), which make flow and transport of water, solutes and gas complex; and (iii) are regarded as fertile soils in many areas. The combination of these characteristics results in the unique soil-aquifer phenomena that are highlighted and summarized in this review. The review is divided into the following four sections: (1) soil cracks as preferential pathways for water and contaminants: in this section lysimeter-to basin-scale observations that show the significance of cracks as preferential-flow paths in vertisols, which bypass matrix blocks in the unsaturated zone, are summarized. Relatively fresh-water recharge and groundwater contamination from these fluxes and their modeling are reviewed; (2) soil cracks as deep evaporators and unsaturated-zone salinity: deep sediment samples under uncultivated vertisols in semiarid regions reveal a dry (immobile), saline matrix, partly due to enhanced evaporation through soil cracks. Observations of this phenomenon are compiled in this section and the mechanism of evapoconcentration due to air flow in the cracks is discussed; (3) impact of cultivation on flushing of the unsaturated zone and aquifer salinization: the third section examines studies reporting that land-use change of vertisols from native land to cropland promotes greater fluxes through the saline unsaturated-zone matrix, eventually flushing salts to the aquifer. Different degrees of salt flushing are assessed as well as aquifer salinization on different scales, and a comparison is made with aquifers under other soils; (4) relatively little nitrate contamination in aquifers under vertisols: in this section we turn the light on observations showing that aquifers under cultivated vertisols are somewhat resistant to groundwater contamination by nitrate (the major agriculturally related

  10. Stratification and Storage of Soil Organic Carbon and Nitrogen as Affected by Tillage Practices in the North China Plain

    PubMed Central

    Zhang, Xiang-Qian; Kong, Fan-Lei; Chen, Fu; Lal, Rattan; Zhang, Hai-Lin

    2015-01-01

    Tillage practices can redistribute the soil profiles, and thus affects soil organic carbon (SOC), and its storage. The stratification ratio (SR) can be an indicator of soil quality. This study was conducted to determine tillage effects on the profile distribution of certain soil properties in winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) systems in the North China Plain (NCP). Three tillage treatments, including no till (NT), rotary tillage (RT), and plow tillage (PT), were established in 2001 in Luancheng County, Hebei Province. The concentration, storage, and SR of SOC and soil total nitrogen (TN) were assessed in both the wheat and maize seasons. Compared with RT and PT, the mean SRs for all depth ratios of SOC under NT increased by 7.85% and 30.61% during the maize season, and by 14.67% and 30.91% during the wheat season, respectively. The SR of TN for 0–5:30–50 cm increased by 140%, 161%, and 161% in the maize season, and 266%, 154%, and 122% in the wheat season compared to the SR for 0–5:5–10 cm under NT, RT and PT, respectively. The data indicated that SOC and TN were both concentrated in the surface-soil layers (0–10 cm) under NT but were distributed relatively evenly through the soil profile under PT. Meanwhile, the storage of SOC and TN was higher under NT for the surface soil (0–10 cm) but was higher under PT for the deeper soil (30–50 cm). Furthermore, the storage of SOC and TN was significantly related to SR of SOC and TN along the whole soil profile (P<0.0001). Therefore, SR could be used to explain and indicate the changes in the storage of SOC and TN. Further, NT stratifies SOC and TN, enhances the topsoil SOC storage, and helps to improve SOC sequestration and soil quality. PMID:26075391

  11. Hygrothermal Material Properties for Soils in Building Science

    SciTech Connect

    Pallin, Simon B; Kehrer, Manfred

    2013-01-01

    Hygrothermal performance of soils coupled to buildings is complicated because of the dearth of information on soil properties. However they are important when numerical simulation of coupled heat and moisture transport for below-grade building components are performed as their temperature and moisture content has an influence on the durability of the below-grade building component. Soils can be classified by soil texture. According to the Unified Soil Classification System (USCA), 12 different soils can be defined on the basis of three soil components: clay, sand, and silt. This study shows how existing material properties for typical American soils can be transferred and used for the calculation of the coupled heat and moisture transport of building components in contact with soil. Furthermore a thermal validation with field measurements under known boundary conditions is part of this study, too. Field measurements for soil temperature and moisture content for two specified soils are carried out right now under known boundary conditions. As these field measurements are not finished yet, the full hygrothermal validation is still missing.

  12. Micronutrient Fractionation in Coal Mine-Affected Agricultural Soils, India.

    PubMed

    Agrawal, Rahul; Kumar, Bijendra; Priyanka, Kumari; Narayan, Chandravir; Shukla, Kriti; Sarkar, Jhuma; Anshumali

    2016-04-01

    Assessment of the anthropogenic impacts on bioavailability, mobility, immobility and toxicity of four micronutrients (Cu, Fe, Mn, and Zn) were carried out by Community Bureau of Reference (BCR) fractionation scheme in agricultural soils (n = 10) around Jharia coalfield, eastern India. The relative abundance of micronutrients was as follows: Fe > Mn > Zn > Cu. The enrichment factor was >1 for Zn (6.1) and Cu (1.8) near coal mining area indicated toward soil pollution due to coal mining activities and application of inorganic fertilizers. The I geo values of micronutrients were <0 suggest no pollution with respect to Cu, Fe, Mn and Zn. Correlation analysis showed geogenic origin of soil micronutrients and derived mainly from weathering of minerals present in the parent rock. The mean values of Cu, Mn and Zn were less than certified reference material indicating highly leached agricultural soils in the study region. BCR fractionation of micronutrients showed that a single element could not reveal all types of chemical reactions occurring in soil consortium. PMID:26886429

  13. Soil microbes and plant invasions—how soil-borne pathogens regulate plant populations and affect plant invasions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Exotic plant invaders are a major global threat to biodiversity and ecosystem function. Here I present multiple lines of evidence suggesting that soil microbial communities affect the population growth rates of Prunus serotina in its native range and affect its invasiveness abroad. Research often ...

  14. Spatial and temporal patterns of apparent electrical conductivity: DUALEM vs. Veris sensors for monitoring soil properties.

    PubMed

    Serrano, João; Shahidian, Shakib; Silva, José Marques da

    2014-01-01

    The main objective of this study was to compare two apparent soil electrical conductivity (ECa) sensors (Veris 2000 XA and DUALEM 1S) for mapping variability of soil properties in a Mediterranean shallow soil. This study also aims at studying the effect of soil cover vegetation on the ECa measurement by the two types of sensors. The study was based on two surveys carried out under two very different situations: in February of 2012, with low soil moisture content (SMC) and with high and differentiated vegetation development (non grazed pasture), and in February of 2013, with high SMC and with short and relatively homogeneous vegetation development (grazed pasture). The greater temporal stability of Veris sensor, despite the wide variation in the SMC and vegetation ground cover indicates the suitability of using this sensor for monitoring soil properties in permanent pastures. The survey carried out with the DUALEM sensor in 2012 might have been affected by the presence of a 0.20 m vegetation layer at the soil surface, masking the soil properties. These differences should be considered in the selection of ECa sensing systems for a particular application. PMID:24915182

  15. Spatial and Temporal Patterns of Apparent Electrical Conductivity: DUALEM vs. Veris Sensors for Monitoring Soil Properties

    PubMed Central

    Serrano, João; Shahidian, Shakib; da Silva, José Marques

    2014-01-01

    The main objective of this study was to compare two apparent soil electrical conductivity (ECa) sensors (Veris 2000 XA and DUALEM 1S) for mapping variability of soil properties in a Mediterranean shallow soil. This study also aims at studying the effect of soil cover vegetation on the ECa measurement by the two types of sensors. The study was based on two surveys carried out under two very different situations: in February of 2012, with low soil moisture content (SMC) and with high and differentiated vegetation development (non grazed pasture), and in February of 2013, with high SMC and with short and relatively homogeneous vegetation development (grazed pasture). The greater temporal stability of Veris sensor, despite the wide variation in the SMC and vegetation ground cover indicates the suitability of using this sensor for monitoring soil properties in permanent pastures. The survey carried out with the DUALEM sensor in 2012 might have been affected by the presence of a 0.20 m vegetation layer at the soil surface, masking the soil properties. These differences should be considered in the selection of ECa sensing systems for a particular application. PMID:24915182

  16. Lotung downhole array. 2: Evaluation of soil nonlinear properties

    SciTech Connect

    Zeghal, M.; Elgamal, A.W.; Tang, H.T.; Stepp, J.C.

    1995-04-01

    The characteristics of soil response during earthquake excitations, at a site in Lotung, Taiwan are identified using the Lotung large scale seismic test (LSST) data. A technique is developed to evaluate soil shear stress-strain histories directly from the free-field downhole accelerations. These histories are used to estimate variation of soil shear moduli and material damping characteristics with shear strain amplitude, and to assess the effects of pore pressure buildup. Soil stiffness properties are found to compare satisfactorily with those obtained through laboratory tests conducted by the University of California, Davis; the National Taiwan University; and the University of Texas at Austin. Pore pressure buildup appears to be accompanied by a reduction in soil stiffness. The information obtained in this study demonstrates that downhole accelerometer and pore pressure arrays offer a direct effective means of evaluating seismic soil properties.

  17. Spatial Variability of Soil Fertility Properties for Precision Agriculture in Southern Iran

    NASA Astrophysics Data System (ADS)

    Yasrebi, Jafar; Saffari, Mahboub; Fathi, Hamed; Karimian, Najafali; Emadi, Mostafa; Baghernejad, Majid

    The objective of this study was to determine the degree of spatial variability of soil chemical properties, soil texture and variance structure. Spatial distributions for 13 soil chemical properties and soil texture were examined in a fallow land in Bajgah, Fars province, Iran. Soil samples were collected at approximately 60 m2 at 0-30 cm depth and coordinates of each of the 100 points were recorded with GPS. The spatial distribution and spatial dependence level varied within location. The range of spatial dependence was found to vary within soil parameters. Phosphorous had the shortest range of spatial dependence (49.50 m) and percentage of calcium carbonate equivalent had the longest (181.94 m). All parameters exhibited strongly spatially dependent. The results demonstrate that within the same field, spatial patterns vary among several soil parameters. Soil nutrients were found to be affected by farmer management. Variography and kriging can be useful tools for designing effective soil sampling strategies and variable rate application of inputs for use in site-specific farming.

  18. Crop response to localized organic amendment in soils with limiting physical properties

    NASA Astrophysics Data System (ADS)

    Lordan, Joan; Pascual, Miquel; Fonseca, Francisco; Villar, Josep Maria; Montilla, Victor; Papió, Josep; Rufat, Josep

    2013-04-01

    This 2-year study evaluated the use of rice husk as a localized organic amendment in a soil with limiting physical properties. The research was conducted in a commercial peach orchard planted in 2011 using a ridge planting system. Six soil and water management treatments were evaluated in 18 experimental units, which were set up in the field using a randomized complete block design. The treatments were compared both in terms of soil physical properties and crop response. Soil amendment with rice husk was the most effective technique. It improved soil conditions (soil infiltration and soil porosity), providing a better soil environment for root activity and thereby resulted in better crop performance. Concerning growth parameters, the amended treatment presented the highest overall values without negatively affecting crop water status. These techniques were suitable for mitigating the effects of soils with limiting physical conditions. Localized applications of amendments, as proposed in this work, imply an important reduction in application rates. It is important to consider an efficient use of by-products since there is a growing interest in industrial and agronomical exploitations.

  19. Different tree species affect soil respiration spatial distribution in a subtropical forest of southern Taiwan

    NASA Astrophysics Data System (ADS)

    Chiang, Po-Neng; Yu, Jui-Chu; Wang, Ya-nan; Lai, Yen-Jen

    2014-05-01

    Global forests contain 69% of total carbon stored in forest soil and litter. But the carbon storage ability and release rate of warming gases of forest soil also affect global climate change. Soil carbon cycling processes are paid much attention by ecological scientists and policy makers because of the possibility of carbon being stored in soil via land use management. Soil respiration contributed large part of terrestrial carbon flux, but the relationship of soil respiration and climate change was still obscurity. Most of soil respiration researches focus on template and tropical area, little was known that in subtropical area. Afforestation is one of solutions to mitigate CO2 increase and to sequestrate CO2 in tree and soil. Therefore, the objective of this study is to clarify the relationship of tree species and soil respiration distribution in subtropical broad-leaves plantation in southern Taiwan. The research site located on southern Taiwan was sugarcane farm before 2002. The sugarcane was removed and fourteen broadleaved tree species were planted in 2002-2005. Sixteen plots (250m*250m) were set on 1 km2 area, each plot contained 4 subplots (170m2). The forest biomass (i.e. tree height, DBH) understory biomass, litter, and soil C were measured and analyzed at 2011 to 2012. Soil respiration measurement was sampled in each subplot in each month. The soil belongs to Entisol with over 60% of sandstone. The soil pH is 5.5 with low base cations because of high sand percentage. Soil carbon storage showed significantly negative relationship with soil bulk density (p<0.001) in research site. The differences of distribution of live tree C pool among 16 plots were affected by growth characteristic of tree species. Data showed that the accumulation amount of litterfall was highest in December to February and lowest in June. Different tree species planted in 16 plots, resulting in high spatial variation of litterfall amount. It also affected total amount of litterfall

  20. Thermal properties of degraded lowland peat-moorsh soils

    NASA Astrophysics Data System (ADS)

    Gnatowski, Tomasz

    2016-04-01

    Soil thermal properties, i.e.: specific heat capacity (c), thermal conductivity (K), volumetric heat capacity (C) govern the thermal environment and heat transport through the soil. Hence the precise knowledge and accurate predictions of these properties for peaty soils with high amount of organic matter are especially important for the proper forecasting of soil temperature and thus it may lead to a better assessment of the greenhouse gas emissions created by microbiological activity of the peatlands. The objective of the study was to develop the predictive models of the selected thermal parameters of peat-moorsh soils in terms of their potential applicability for forecasting changes of soil temperature in degraded ecosystems of the Middle Biebrza River Valley area. Evaluation of the soil thermal properties was conducted for the parameters: specific heat capacity (c), volumetric heat capacities of the dry and saturated soil (Cdry, Csat) and thermal conductivities of the dry and saturated soil (Kdry, Ksat). The thermal parameters were measured using the dual-needle probe (KD2-Pro) on soil samples collected from seven peaty soils, representing total 24 horizons. The surface layers were characterized by different degrees of advancement of soil degradation dependent on intensiveness of the cultivation practises (peaty and humic moorsh). The underlying soil layers contain peat deposits of different botanical composition (peat-moss, sedge-reed, reed and alder) and varying degrees of decomposition of the organic matter, from H1 to H7 (von Post scale). Based on the research results it has been shown that the specific heat capacity of the soils differs depending on the type of soil (type of moorsh and type of peat). The range of changes varied from 1276 J.kg‑1.K‑1 in the humic moorsh soil to 1944 J.kg‑1.K‑1 in the low decomposed sedge-moss peat. It has also been stated that in degraded peat soils with the increasing of the ash content in the soil the value of

  1. Spatial heterogeneity of plant-soil feedback affects root interactions and interspecific competition.

    PubMed

    Hendriks, Marloes; Ravenek, Janneke M; Smit-Tiekstra, Annemiek E; van der Paauw, Jan Willem; de Caluwe, Hannie; van der Putten, Wim H; de Kroon, Hans; Mommer, Liesje

    2015-08-01

    Plant-soil feedback is receiving increasing interest as a factor influencing plant competition and species coexistence in grasslands. However, we do not know how spatial distribution of plant-soil feedback affects plant below-ground interactions. We investigated the way in which spatial heterogeneity of soil biota affects competitive interactions in grassland plant species. We performed a pairwise competition experiment combined with heterogeneous distribution of soil biota using four grassland plant species and their soil biota. Patches were applied as quadrants of 'own' and 'foreign' soils from all plant species in all pairwise combinations. To evaluate interspecific root responses, species-specific root biomass was quantified using real-time PCR. All plant species suffered negative soil feedback, but strength was species-specific, reflected by a decrease in root growth in own compared with foreign soil. Reduction in root growth in own patches by the superior plant competitor provided opportunities for inferior competitors to increase root biomass in these patches. These patterns did not cascade into above-ground effects during our experiment. We show that root distributions can be determined by spatial heterogeneity of soil biota, affecting plant below-ground competitive interactions. Thus, spatial heterogeneity of soil biota may contribute to plant species coexistence in species-rich grasslands. PMID:25871977

  2. Effect of land use change on soil properties and functions

    NASA Astrophysics Data System (ADS)

    Tonutare, Tonu; Kõlli, Raimo; Köster, Tiina; Rannik, Kaire; Szajdak, Lech; Shanskiy, Merrit

    2014-05-01

    For good base of sustainable land management and ecologically sound protection of soils are researches on soil properties and functioning. Ecosystem approach to soil properties and functioning is equally important in both natural and cultivated land use conditions. Comparative analysis of natural and agro-ecosystems formed on similar soil types enables to elucidate principal changes caused by land use change (LUC) and to elaborate the best land use practices for local pedo-ecological conditions. Taken for actual analysis mineral soils' catena - rendzina → brown soils → pseudopodzolic soils → gley-podzols - represent ca 1/3 of total area of Estonian normal mineral soils. All soils of this catena differ substantially each from other by calcareousness, acidity, nutrition conditions, fabric and humus cover type. This catena (representative to Estonian pedo-ecological conditions) starts with drought-prone calcareous soils. Brown (distributed in northern and central Estonia) and pseudopodzolic soils (in southern Estonia) are the most broadly acknowledged for agricultural use medium-textured high-quality automorphic soils. Dispersedly distributed gley-podzols are permanently wet and strongly acid, low-productivity sandy soils. In presentation four complex functions of soils are treated: (1) being a suitable soil environment for plant cover productivity (expressed by annual increment, Mg ha-1 yr-1); (2) forming adequate conditions for decomposition, transformation and conversion of fresh falling litter (characterized by humus cover type); (3) deposition of humus, individual organic compounds, plant nutrition elements, air and water, and (4) forming (bio)chemically variegated active space for soil type specific edaphon. Capacity of soil cover as depositor (3) depends on it thickness, texture, calcareousness and moisture conditions. Biological activity of soil (4) is determined by fresh organic matter influx, quality and quantity of biochemical substances and humus

  3. Characterizing recovery of soil hydrological properties impacted by wildfire

    NASA Astrophysics Data System (ADS)

    Joseph, Alicia; Borak, Jordan; Yatheendradas, Soni; Crosgrove, Brian; Gochis, David; Dugger, Aubrey; Goodrich, David

    2016-04-01

    Accurate characterization of the post-burn recovery of soil properties over time is important for hydrological modeling applications. Yet, this recovery remains not characterized well enough for effective usage as hydrologic model simulation guidelines, for example, by organizations like the NOAA NWS National Water Center for streamflow modeling or like USDA for flash flood modeling. By calibrating a model's soil properties to soil moisture at different short periods of post-fire rain events for an example test case, we attempt to characterize the soil recovery from wildfires as a function of the burn severity, soil properties, hydrologic states like moisture and antecedent rain history post-burn, and ecosystem vegetation type and plant cover density. This work is in line with similar recent work but focuses more on improving predictability for operational hydrologic applications.

  4. Sensitivity of Polygonum aviculare Seeds to Light as Affected by Soil Moisture Conditions

    PubMed Central

    Batlla, Diego; Nicoletta, Marcelo; Benech-Arnold, Roberto

    2007-01-01

    Background and Aims It has been hypothesized that soil moisture conditions could affect the dormancy status of buried weed seeds, and, consequently, their sensitivity to light stimuli. In this study, an investigation is made of the effect of different soil moisture conditions during cold-induced dormancy loss on changes in the sensitivity of Polygonum aviculare seeds to light. Methods Seeds buried in pots were stored under different constant and fluctuating soil moisture environments at dormancy-releasing temperatures. Seeds were exhumed at regular intervals during storage and were exposed to different light treatments. Changes in the germination response of seeds to light treatments during storage under the different moisture environments were compared in order to determine the effect of soil moisture on the sensitivity to light of P. aviculare seeds. Key Results Seed acquisition of low-fluence responses during dormancy release was not affected by either soil moisture fluctuations or different constant soil moisture contents. On the contrary, different soil moisture environments affected seed acquisition of very low fluence responses and the capacity of seeds to germinate in the dark. Conclusions The results indicate that under field conditions, the sensitivity to light of buried weed seeds could be affected by the soil moisture environment experienced during the dormancy release season, and this could affect their emergence pattern. PMID:17430979

  5. Soil microbiological properties and enzymatic activities of long-term post-fire recovery in dry and semiarid Aleppo pine (Pinus halepensis M.) forest stands

    NASA Astrophysics Data System (ADS)

    Hedo, J.; Lucas-Borja, M. E.; Wic, C.; Andrés-Abellán, M.; de Las Heras, J.

    2015-02-01

    Wildfires affecting forest ecosystems and post-fire silvicultural treatments may cause considerable changes in soil properties. The capacity of different microbial groups to recolonise soil after disturbances is crucial for proper soil functioning. The aim of this work was to investigate some microbial soil properties and enzyme activities in semiarid and dry Aleppo pine (Pinus halepensis M.) forest stands. Different plots affected by a wildfire event 17 years ago without or with post-fire silvicultural treatments 5 years after the fire event were selected. A mature Aleppo pine stand, unaffected by wildfire and not thinned was used as a control. Physicochemical soil properties (soil texture, pH, carbonates, organic matter, electrical conductivity, total N and P), soil enzymes (urease, phosphatase, β-glucosidase and dehydrogenase activities), soil respiration and soil microbial biomass carbon were analysed in the selected forests areas and plots. The main finding was that long time after this fire event produces no differences in the microbiological soil properties and enzyme activities of soil after comparing burned and thinned, burned and not thinned, and mature plots. Moreover, significant site variation was generally seen in soil enzyme activities and microbiological parameters. We conclude that total vegetation recovery normalises post-fire soil microbial parameters, and that wildfire and post-fire silvicultural treatments are not significant factors affecting soil properties after 17 years.

  6. Do long-lived ants affect soil microbial communities?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study was designed to test the hypothesis that desert ant species that build nests that remain viable at a particular point in space for more than a decade produce soil conditions that enhance microbial biomass and functional diversity. We studied the effects of a seed-harvester ant, Pogonomyrm...

  7. Using Gypsum to Affect Soil Erosion Processes and Water Quality

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A driving force in soil erosion is the low electrolyte content of rain water. Various electrolyte sources have proven useful in serving as electrolyte sources such as phosphogypsum, lime and various salts, however, each has other potential problems. We performed a number of studies on low cost gypsu...

  8. Soil Aggregation and Enzyme Activities as affected by Management Practices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The predominant cropping system in the Central Great Plains, winter Wheat-Fallow (W-F) rotation, is associated with decreases in Soil Organic Matter (SOM) primarily because of tillage during the fallow period. Intensive cropping with reduced tillage and fallow are practices that provide more residue...

  9. How irrigation affects soil erosion estimates of RUSLE2

    Technology Transfer Automated Retrieval System (TEKTRAN)

    RUSLE2 is a robust and computationally efficient conservation planning tool that estimates soil, climate, and land management effects on sheet and rill erosion and sediment delivery from hillslopes, and also estimates the size distribution and clay enrichment of sediment delivered to the channel sys...

  10. Low-Temperature Biochar Affects an Eroded Calcareous Soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous research showed little benefit from using a high temperature, high pH biochar for improving the fertility of eroded calcareous soils. We thus explored the potential of an activated, low-temperature, low pH biochar to improve their fertility status. In a microcosm study conducted at 20 de...

  11. Aminopyralid soil residues affect rotational vegetable crops in Florida

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Field experiments were conducted to determine the sensitivity of bell pepper, eggplant, tomato, muskmelon, and watermelon to aminopyralid soil residues. Aminopyralid was applied at six rates ranging from 0.0014 kg ae ha 1 to 0.0448 kg ae ha 1, and vegetable crops were planted in the treated areas. ...

  12. Does Gray-Tailed Vole Activity Affect Soil Quality?

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Voles are well-known crop pests, especially when peak populations are present, but their role in soil fertility and impacts on agricultural sustainability are not well understood. Five months after the abrupt disappearance of a peak in a gray-tailed vole (Microtus canicaudus) population, we examined...

  13. Stimulatory Effects of Arsenic-Tolerant Soil Fungi on Plant Growth Promotion and Soil Properties

    PubMed Central

    Srivastava, Pankaj Kumar; Shenoy, Belle Damodara; Gupta, Manjul; Vaish, Aradhana; Mannan, Shivee; Singh, Nandita; Tewari, Shri Krishna; Tripathi, Rudra Deo

    2012-01-01

    Fifteen fungi were obtained from arsenic-contaminated agricultural fields in West Bengal, India and examined for their arsenic tolerance and removal ability in our previous study. Of these, the four best arsenic-remediating isolates were tested for plant growth promotion effects on rice and pea in the present study. A greenhouse-based pot experiment was conducted using soil inocula of individual fungi. The results indicated a significant (P<0.05) increase in plant growth and improvement of soil properties in inoculated soils compared to the control. A significant increase in plant growth was recorded in treated soils and varied from 16–293%. Soil chemical and enzymatic properties varied from 20–222% and 34–760%, respectively, in inoculated soil. Plants inoculated with inocula of Westerdykella and Trichoderma showed better stimulatory effects on plant growth and soil nutrient availability than Rhizopus and Lasiodiplodia. These fungi improved soil nutrient content and enhanced plant growth. These fungi may be used as bioinoculants for plant growth promotion and improved soil properties in arsenic-contaminated agricultural soils. PMID:23047145

  14. Combining phytoextraction and biochar addition improves soil biochemical properties in a soil contaminated with Cd.

    PubMed

    Lu, Huanping; Li, Zhian; Fu, Shenglei; Méndez, Ana; Gascó, Gabriel; Paz-Ferreiro, Jorge

    2015-01-01

    The main goal of phytoremediation is to improve ecosystem functioning. Soil biochemical properties are considered as effective indicators of soil quality and are sensitive to various environmental stresses, including heavy metal contamination. The biochemical response in a soil contaminated with cadmium was tested after several treatments aimed to reduce heavy metal availability including liming, biochar addition and phytoextraction using Amaranthus tricolor L. Two biochars were added to the soil: eucalyptus pyrolysed at 600 °C (EB) and poultry litter at 400 °C (PLB). Two liming treatments were chosen with the aim of bringing soil pH to the same values as in the treatments EB and PLB. The properties studied included soil microbial biomass C, soil respiration and the activities of invertase, β-glucosidase, β-glucosaminidase, urease and phosphomonoesterase. Both phytoremediation and biochar addition improved soil biochemical properties, although results were enzyme specific. For biochar addition these changes were partly, but not exclusively, mediated by alterations in soil pH. A careful choice of biochar must be undertaken to optimize the remediation process from the point of view of metal phytoextraction and soil biological activity. PMID:25010741

  15. Soil physicochemical properties after 10 years of animal waste applications

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Application of animal waste to cropland provides a method of waste disposal and benefits both soil and crops. The objective of this study was to evaluate the long-term effects of land application of animal waste and inorganic fertilizer on selected soil chemical and physical properties. The animal w...

  16. Predicting the impact of biochar additions on soil hydraulic properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Different physical and chemical properties of biochar, which is made out of a variety of biomass materials, can impact water movement through amended soil. The objective of this research was to develop a decision support tool predicting the impact of biochar additions on soil saturated hydraulic con...

  17. SOIL PROPERTIES OF SITES USED FOR COMPOSTING ANIMAL MANURE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Long-term animal manure composting creates zones of high soil nutrient and salinity. Once the composting operation is terminated, there is a need to reclaim the sites for agricultural crops. The objective of this study is to evaluate soil properties and performance of corn (Zea mays), sorghum (Sor...

  18. Soil biochemical properties in brown and gray mine soils with and without hydroseeding

    NASA Astrophysics Data System (ADS)

    Thomas, C.; Sexstone, A.; Skousen, J.

    2015-09-01

    Surface coal mining in the eastern USA disturbs hundreds of hectares of land every year and removes valuable and ecologically diverse eastern deciduous forests. Reclamation involves restoring the landscape to approximate original contour, replacing the topsoil, and revegetating the site with trees and herbaceous species to a designated post-mining land use. Re-establishing an ecosystem of ecological and economic value as well as restoring soil quality on disturbed sites are the goals of land reclamation, and microbial properties of mine soils can be indicators of restoration success. Reforestation plots were constructed in 2007 using weathered brown sandstone or unweathered gray sandstone as topsoil substitutes to evaluate tree growth and soil properties at Arch Coal's Birch River mine in West Virginia, USA. All plots were planted with 12 hardwood tree species and subplots were hydroseeded with a herbaceous seed mix and fertilizer. After 6 years, the average tree volume index was nearly 10 times greater for trees grown in brown (3853 cm3) compared to gray mine soils (407 cm3). Average pH of brown mine soils increased from 4.7 to 5.0, while gray mine soils declined from 7.9 to 7.0. Hydroseeding doubled tree volume index and ground cover on both mine soils. Hydroseeding doubled microbial biomass carbon (MBC) on brown mine soils (8.7 vs. 17.5 mg kg-1), but showed no effect on gray mine soils (13.3 vs. 12.8 mg kg-1). Hydroseeding also increased the ratio of MBC to soil organic C in both soils and more than tripled the ratio for potentially mineralizable nitrogen (PMN) to total N. Brown mine soils were a better growth medium than gray mine soils and hydroseeding was an important component of reclamation due to improved biochemical properties and microbial activity in mine soils.

  19. Regional Study of No-Till Impacts on Near-Surface Aggregate Properties that Influence Soil Erodibility

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The extent to which tillage systems modify the near-surface soil aggregate properties affecting soil’s susceptibility to erosion by water and wind is not well understood. We hypothesized that an increase in soil organic carbon (SOC) content with conservation tillage systems, particularly NT, may imp...

  20. Grazing management, season, and drought contributions to near-surface soil property dynamics and greenhouse gas flux in semiarid rangeland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Semiarid rangelands provide an array of ecosystem services, yet the role of grazing management and environmental conditions to affect rangeland soil function is poorly understood. A study was conducted to assess effects of grazing management, season, and drought on soil property dynamics and greenh...

  1. Chemical and biological properties in the rhizosphere of Lupinus albus alter soil heavy metal fractionation.

    PubMed

    Martínez-Alcalá, I; Walker, D J; Bernal, M P

    2010-05-01

    To understand better the suitability of white lupin (Lupinus albus L.) for phytoremediation of heavy metal-contaminated soils, the effect of its roots on chemical and biological properties of the rhizosphere affecting soil metal fractionation was studied. Plants were cultivated in two similar soils, with high levels of Zn, Cd, Cu and Pb but differing pH values (4.2 and 6.8). In the rhizosphere of both soils, its roots induced increases in water-soluble carbon, which influenced the fractionation of heavy metals and ultimately their uptake by plant roots. In the rhizosphere of the acid soil, the concentrations of 0.1M CaCl(2)-extractable Mn, Zn and Cu were lower than in the bulk soil, possibly due to their increased retention on Fe (III) hydroxides/oxyhydroxides, while in the neutral soil only the Zn concentration was lower. Higher concentrations of heavy metals were found in plants growing on the acid soil, reflecting their greater availability in this soil. The restricted transfer of heavy metals to the shoot confirms the potential role of this species in the initial phytoimmobilisation of heavy metals, particularly in neutral-alkaline soils. PMID:20060590

  2. Estimating Soil Cation Exchange Capacity from Soil Physical and Chemical Properties

    NASA Astrophysics Data System (ADS)

    Bateni, S. M.; Emamgholizadeh, S.; Shahsavani, D.

    2014-12-01

    The soil Cation Exchange Capacity (CEC) is an important soil characteristic that has many applications in soil science and environmental studies. For example, CEC influences soil fertility by controlling the exchange of ions in the soil. Measurement of CEC is costly and difficult. Consequently, several studies attempted to obtain CEC from readily measurable soil physical and chemical properties such as soil pH, organic matter, soil texture, bulk density, and particle size distribution. These studies have often used multiple regression or artificial neural network models. Regression-based models cannot capture the intricate relationship between CEC and soil physical and chemical attributes and provide inaccurate CEC estimates. Although neural network models perform better than regression methods, they act like a black-box and cannot generate an explicit expression for retrieval of CEC from soil properties. In a departure with regression and neural network models, this study uses Genetic Expression Programming (GEP) and Multivariate Adaptive Regression Splines (MARS) to estimate CEC from easily measurable soil variables such as clay, pH, and OM. CEC estimates from GEP and MARS are compared with measurements at two field sites in Iran. Results show that GEP and MARS can estimate CEC accurately. Also, the MARS model performs slightly better than GEP. Finally, a sensitivity test indicates that organic matter and pH have respectively the least and the most significant impact on CEC.

  3. Sorption of tannin-C by soils affects soil cation exchange capacity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Some tannins, produced by plants, are able to sorb to soil, and thus influence soil organic matter and nutrient cycling. However, studies are needed that compare sorption of tannins to other related phenolic compounds, evaluate their effects across a broad range of soils, and determine if sorption ...

  4. Hygrothermal Simulations of Foundations: Part 1 - Soil Material Properties

    SciTech Connect

    Pallin, Simon B; Kehrer, Manfred

    2013-01-01

    Hygrothermal performance of soils coupled to buildings is a complicated process. The computational approach for heat transfer via the ground is well defined (EN-ISO-13370:, 2007) together with simplified methods (Staszczuk, Radon, & Holm). Though the soil moisture transfer is generally ignored, it is proven not negligible (Janssen, Carmeliet, & Hens, 2004). Even though reliable material properties of soils are required to perform realistic hygrothermal calculations of soils coupled to buildings, such material properties have not been well defined in hygrothermal calculations tools. Typical building constructions which are greatly influenced by soils are basements, crawl spaces and slab on grade and reliable hygrothermal performance of such construction are highly requested; as it is ranked within the top 10 Building America Enclosure Research Ideas according to Enclosures STC - Residential Energy Efficiency Stakeholder Meeting, February 29, 2012 Austin, TX. There exists an extensive amount of measurements on soil properties in Soil Science though this information must be gathered as well as adapted to be applicable in Building Science and for hygrothermal simulation purposes. Soil properties are important when analyzing and designing both new building constructions and retrofitting measures, where the outer boundary of the buildings enclosure consists of soil materials. Concerning basement energy retrofits, interior solutions of improving the energy demand has to cooperate with the existing soil properties and must therefore be designed thereafter. In concerns of exterior retrofits, the soil material can be replaced, if needed, with a more suitable filling material, though this approach applies only for basement walls. The soil material beneath the basement floor can naturally not be replaced hence the soil properties of this part of the buildings enclosure still must be taken into consideration. This study is divided into several parts. The intention of the first

  5. Soil degradation and amendment effects on soil properties, microbial communities, and plant growth

    NASA Astrophysics Data System (ADS)

    Gebhardt, M.; Fehmi, J. S.; Rasmussen, C.; Gallery, R. E.

    2015-12-01

    Human activities that disrupt soil properties are fundamentally changing ecosystems. Soil degradation, caused by anthropogenic disturbance can decrease microbial abundance and activity, leading to changes in nutrient availability, soil organic matter, and plant establishment. The addition of amendments to disturbed soils have the potential ameliorate these negative consequences. We studied the effects of soil degradation, via an autoclave heat shock method, and the addition of amendments (biochar and woodchips) on microbial activity, soil carbon and nitrogen availability, microbial biomass carbon and nitrogen content, and plant growth of ten plant species native to the semi-arid southwestern US. Relative to non-degraded soils, microbial activity, measured via extracellular enzyme assays, was significantly lower for all seven substrates assayed. These soils also had significantly lower amounts of carbon assimilated into microbial biomass but no change in microbial biomass nitrogen. Soil degradation had no effect on plant biomass. Amendments caused changes in microbial activity: biochar-amended soils had significant increases in potential activity with five of the seven substrates measured; woodchip amended soils had significant increases with two. Soil carbon increased with both amendments but this was not reflected in a significant change in microbial biomass carbon. Biochar-amended soils had increases in soil nitrogen availability but neither amendment caused changes in microbial biomass nitrogen. Biochar amendments had no significant effect on above- or belowground plant biomass while woodchips significantly decreased aboveground plant biomass. Results show that soil degradation decreases microbial activity and changes nutrient dynamics, but these are not reflected in changes in plant growth. Amendments provide nutrient sources and change soil pore space, which cause microbial activities to fluctuate and may, in the case of woodchips, increase plant drought

  6. Physical and mechanical properties of the lunar soil (a review)

    NASA Astrophysics Data System (ADS)

    Slyuta, E. N.

    2014-09-01

    We review the data on the physical and mechanical properties of the lunar soil that were acquired in the direct investigations on the lunar surface carried out in the manned and automatic missions and in the laboratory examination of the lunar samples returned to the Earth. In justice to the American manned program Apollo, we show that a large volume of the data on the properties of the lunar soil was also obtained in the Soviet automatic program Lunokhod and with the automatic space stations Luna-16, -20, and -24 that returned the lunar soil samples to the Earth. We consider all of the main physical and mechanical properties of the lunar soil, such as the granulometric composition, density and porosity, cohesion and adhesion, angle of internal friction, shear strength of loose soil, deformation characteristics (the deformation modulus and Poisson ratio), compressibility, and the bearing capacity, and show the change of some properties versus the depth. In most cases, the analytical dependence of the main parameters is presented, which is required in developing reliable engineering models of the lunar soil. The main physical and mechanical properties are listed in the summarizing table, and the currently available models and simulants of the lunar soil are reviewed.

  7. Nonequilibrium water dynamics in the rhizosphere: How mucilage affects water flow in soils

    NASA Astrophysics Data System (ADS)

    Kroener, Eva; Zarebanadkouki, Mohsen; Kaestner, Anders; Carminati, Andrea

    2014-08-01

    The flow of water from soil to plant roots is controlled by the properties of the narrow region of soil close to the roots, the rhizosphere. In particular, the hydraulic properties of the rhizosphere are altered by mucilage, a polymeric gel exuded by the roots. In this paper we present experimental results and a conceptual model of water flow in unsaturated soils mixed with mucilage. A central hypothesis of the model is that the different drying/wetting rate of mucilage compared to the bulk soil results in nonequilibrium relations between water content and water potential in the rhizosphere. We coupled this nonequilibrium relation with the Richards equation and obtained a constitutive equation for water flow in soil and mucilage. To test the model assumptions, we measured the water retention curve and the saturated hydraulic conductivity of sandy soil mixed with mucilage from chia seeds. Additionally, we used neutron radiography to image water content in a layer of soil mixed with mucilage during drying and wetting cycles. The radiographs demonstrated the occurrence of nonequilibrium water dynamics in the soil-mucilage mixture. The experiments were simulated by numerically solving the nonequilibrium model. Our study provides conceptual and experimental evidences that mucilage has a strong impact on soil water dynamics. During drying, mucilage maintains a greater soil water content for an extended time, while during irrigation it delays the soil rewetting. We postulate that mucilage exudation by roots attenuates plant water stress by modulating water content dynamics in the rhizosphere.

  8. Linear and Nonlinear Ultrasonic Properties of Granular Soils

    SciTech Connect

    Bonner, B.; Berge, P.A.; Aracne-Ruddle, C.M.; Bertete-Auguirre, H.; Wildenschild, D.; Trombino, C.N.; Hardy, E.

    2000-04-20

    The ultrasonic pulse transmission method (100-500 kHz) was adapted to measure compressional (P) and shear (S) wave velocities for synthetic soils fabricated from quartz-clay and quartz-peat mixtures. Velocities were determined as samples were loaded by small (up to 0.1 MPa) uniaxial stress to determine how stress at grain contacts affects ave amplitudes, velocities, and frequency content. Samples were fabricated from quartz sand mixed with either a swelling clay or peat (natural cellulose). P velocities in these dry synthetic soil samples were low, ranging from about 230 to 430 m/s for pure sand, about 91 to 420 m/s for sand-peat mixtures, and about 230 to 470 m/s for dry sand-clay mixtures. S velocities were about half of the P velocity in most cases, about 130 to 250 m/s for pure sand, about 75-220 m/s for sand-peat mixtures, and about 88-220 m/s for dry sand-clay mixtures. These experiments demonstrate that P and S velocities are sensitive to the amount and type of admixed second phase at low concentrations. They found that dramatic increases in all velocities occur with small uniaxial loads, indicating strong nonlinearity of the acoustic properties. Composition and grain packing contribute to the mechanical response at grain contacts and the nonlinear response at low stresses.

  9. Geochemistry Of Lead In Contaminated Soils: Effects Of Soil Physico-Chemical Properties

    NASA Astrophysics Data System (ADS)

    Saminathan, S.; Sarkar, D.; Datta, R.; Andra, S. P.

    2006-05-01

    Lead (Pb) is an environmental contaminant with proven human health effects. When assessing human health risks associated with Pb, one of the most common exposure pathways typically evaluated is soil ingestion by children. However, bioaccessibility of Pb primarily depends on the solubility and hence, the geochemical form of Pb, which in turn is a function of site specific soil chemistry. Certain fractions of ingested soil-Pb may not dissociate during digestion in the gastro-intestinal tract, and hence, may not be available for transport across the intestinal membrane. Therefore, this study is being currently performed to assess the geochemical forms and bioaccessibility of Pb in soils with varying physico-chemical properties. In order to elucidate the level of Pb that can be ingested and assimilated by humans, an in-vitro model that simulates the physiological conditions of the human digestive system has been developed and is being used in this study. Four different types of soils from the Immokalee (an acid sandy soil with minimal Pb retention potential), Millhopper (a sandy loam with high Fe/Al content), Pahokee (a muck soil with more than 80% soil organic matter), and Tobosa series (an alkaline soil with high clay content) were artificially contaminated with Pb as lead nitrate at the rate equivalent to 0, 400, 800, and 1200 mg/kg dry soil. Analysis of soils by a sequential extraction method at time zero (immediately after spiking) showed that Immokalee and Millhopper soils had the highest amount of Pb in exchangeable form, whereas Pahokee and Tobosa soils had higher percentages of carbonate-bound and Fe/Al-bound Pb. The results of in-vitro experiment at time zero showed that majority of Pb was dissolved in the acidic stomach environment in Immokalee, Millhopper, and Tobosa, whereas it was in the intestinal phase in Pahokee soils. Because the soil system is not in equilibrium at time zero, the effect of soil properties on Pb geochemistry is not clear as yet. The

  10. Effect Of Soil Properties On The Geochemical Speciation Of Arsenic In Contaminated Soils: A Greenhouse Study

    NASA Astrophysics Data System (ADS)

    Sharma, S.; Sarkar, D.; Datta, R.

    2005-05-01

    Land-applied arsenical pesticides have contributed elevated soil arsenic (As) levels. Many baseline risk assessments As-contaminated sites assume that all As present in the soil is bioavailable, thereby potentially overestimating the actual health risk. However, risk from As exposure is associated only with those forms of As that are potentially extractable by the human gastrointestinal juices. It has been demonstrated that As may exist in several geochemical forms depending on soil chemical properties, which may or may not be bioavailable. The current study aims at addressing the issue of soil variability on As bioavailability as a function of soil physico-chemical properties in a greenhouse setting involving dynamic interactions between soil, water and plants. Four different soils were chosen based on their potential differences with respect to As reactivity: Immokalee, an acid sand with low extractable Fe/Al, having minimal arsenic retention capacity; Millhopper, an acid sandy loam with high extractable Fe/Al oxides; Pahokee Muck soil with 85% soil organic matter (SOM) as well as high Fe/Al content; and Orelia soil with high clay and Fe/Al content. Soils were amended with sodium arsenate (675 and 1500 mg/Kg). Rice (Oryza sativa) was used as the test crop. A sequential extraction scheme was employed to identify the geochemical forms of As in soils (soluble, exchangeable, organic, Fe/Al-bound, Ca/Mg-bound, residual) immediately after spiking; after 3 mo; and after 6 mo of equilibration time. Concentrations of these As forms were correlated with the in-vitro bioavailable As fractions to identify those As fractions that are most likely to be bioavailable. Results from this study showed that there was little to no plant growth in the contaminated soils. Sequential extractions of the soil indicated that arsenic is strongly adsorbed onto soil amorphous iron/aluminum oxides, and the degree of arsenic retention is a direct function of equilibration time.

  11. Biochar physico-chemical properties as affected by environmental exposure.

    PubMed

    Sorrenti, Giovambattista; Masiello, Caroline A; Dugan, Brandon; Toselli, Moreno

    2016-09-01

    To best use biochar as a sustainable soil management and carbon (C) sequestration technique, we must understand the effect of environmental exposure on its physical and chemical properties because they likely vary with time. These properties play an important role in biochar's environmental behavior and delivery of ecosystem services. We measured biochar before amendment and four years after amendment to a commercial nectarine orchard at rates of 5, 15 and 30tha(-1). We combined two pycnometry techniques to measure skeletal (ρs) and envelope (ρe) density and to estimate the total pore volume of biochar particles. We also examined imbibition, which can provide information about soil hydraulic conductivity. Finally, we investigated the chemical properties, surface, inner layers atomic composition and C1s bonding state of biochar fragments through X-ray photoelectron spectroscopy (XPS). Ageing increased biochar skeletal density and reduced the water imbibition rate within fragments as a consequence of partial pore clogging. However, porosity and the volume of water stored in particles remained unchanged. Exposure reduced biochar pH, EC, and total C, but enhanced total N, nitrate-N, and ammonium-N. X-ray photoelectron spectroscopy analyses showed an increase of O, Si, N, Na, Al, Ca, Mn, and Fe surface (0-5nm) atomic composition (at%) and a reduction of C and K in aged particles, confirming the interactions of biochar with soil inorganic and organic phases. Oxidation of aged biochar fragments occurred mainly in the particle surface, and progressively decreased down to 75nm. Biochar surface chemistry changes included the development of carbonyl and carboxylate functional groups, again mainly on the particle surface. However, changes were noticeable down to 75nm, while no significant changes were measured in the deepest layer, up to 110nm. Results show unequivocal shifts in biochar physical and chemical properties/characteristics over short (~years) timescales. PMID

  12. Production of biochar out of organic urban waste to amend salt affected soils in the basin of Mexico

    NASA Astrophysics Data System (ADS)

    Chavez Garcia, Elizabeth; Siebe, Christina

    2016-04-01

    Biochar is widely recognized as an efficient tool for carbon sequestration and soil fertility. The understanding of its chemical and physical properties, strongly related to the biomass and production conditions, is central to identify the most suitable application of biochar. On the other hand, salt affected soils reduce the value and productivity of extensive areas worldwide. One feasible option to recover them is to add organic amendments, which improve water holding capacity and increase sorption sites for cations as sodium. The former lake Texcoco in the basin of Mexico has been a key area for the control of surface run-off and air quality of Mexico City. However, the high concentrations of soluble salts in their soils do not allow the development of a vegetation cover that protects the soil from wind erosion, being the latter the main cause of poor air quality in the metropolitan area during the dry season. On the other hand, the population of the city produces daily 2000 t of organic urban wastes, which are currently composted. Thus, we tested if either compost or biochar made out of urban organic waste can improve the salt affected soils of former lake Texcoco to grow grass and avoid wind erosion. We examined the physico-chemical properties of biochar produced from urban organic waste under pyrolysis conditions. We also set up a field experiment to evaluate the addition of these amendments into the saline soils of Texcoco. Our preliminary analyses show biochar yield was ca. 40%, it was mainly alkaline (pH: 8-10), with a moderate salt content (electrical conductivity: 0.5-3 mS/cm). We show also results of the initial phase of the field experiment in which we monitor the electrical conductivity, pH, water content, water tension and soil GHG fluxes on small plots amended with either biochar or compost in three different doses.

  13. Soil Microbial Community Dynamics as Influenced by Soil Properties and Landscape Position

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Factors that affect plant growth, whether it is manure addition, season, or soil-type and landscape variability may provide insight on how to better manage agricultural fields through the evaluation of soil microbial activity, biomass and community structure. Thus, an in situ study was conducted to ...

  14. Agricultural soil moisture experiment, Colby, Kansas 1978: Measured and predicted hydrological properties of the soil

    NASA Technical Reports Server (NTRS)

    Arya, L. M. (Principal Investigator)

    1980-01-01

    Predictive procedures for developing soil hydrologic properties (i.e., relationships of soil water pressure and hydraulic conductivity to soil water content) are presented. Three models of the soil water pressure-water content relationship and one model of the hydraulic conductivity-water content relationship are discussed. Input requirements for the models are indicated, and computational procedures are outlined. Computed hydrologic properties for Keith silt loam, a soil typer near Colby, Kansas, on which the 1978 Agricultural Soil Moisture Experiment was conducted, are presented. A comparison of computed results with experimental data in the dry range shows that analytical models utilizing a few basic hydrophysical parameters can produce satisfactory data for large-scale applications.

  15. Impact of temperature on the biological properties of soil

    NASA Astrophysics Data System (ADS)

    Borowik, Agata; Wyszkowska, Jadwiga

    2016-01-01

    The aim of the study was to determine the response of soil microorganisms and enzymes to the temperature of soil. The effect of the temperatures: 5, 10, 15, 20, and 25°C on the biological properties of soil was investigated under laboratory conditions. The study was performed using four different soils differing in their granulometric composition. It was found that 15°C was the optimal temperature for the development of microorganisms in soil. Typically, in the soil, the highest activity of dehydrogenases was observed at 10-15°C, catalase and acid phosphatase - at 15°C, alkaline phosphatase at 20°C, urease and β-glucosidase at 25°C. The highest colony development index for heterotrophic bacteria was recorded in soils incubated at 25°C, while for actinomycetes and fungi at 15°C. The incubation temperature of soil only slightly changed the ecophysiological variety of the investigated groups of microorganisms. Therefore, the observed climate changes might have a limited impact on the soil microbiological activity, because of the high ability of microorganisms to adopt. The response of soil microorganisms and enzymes was more dependent on the soil granulometric composition, organic carbon, and total nitrogen than on its temperature.

  16. [Soil chemical property changes in vegetable greenhouse fields].

    PubMed

    Liu, Yanjun; Jiang, Yong; Liang, Wenju

    2005-11-01

    To explore the changes of soil chemical properties in vegetable greenhouse, a comparative study was carried out with the samples gathered from vegetable greenhouse fields and their adjacent upland fields in Damintun Town, Xinming County, Liaoning Province. The results showed that compared with upland fields, the contents of soil organic carbon and total nitrogen in greenhouse fields increased significantly. At the depth of 0 approximately 30 cm, soil organic carbon in greenhouses of 1-, 4- and 10-year increased by 31.09%, 35.44%, and 66.80%, respectively, compared with the upland soil. Soil nitrate content at the depth of 0 approximately 30 cm in greenhouse fields was 5.05 approximately 12.49 times as much as that in upland fields. The nitrate content in different soil layers increased with the increasing age of greenhouse field., e.g., at the depth of 20 approximately 30 cm, soil nitrate content was significantly higher in 10-year than in 1- and 4-year greenhouse field, with an increase of 65.73% and 50.89%, respectively, and 6.55 times as much as that in upland field, which indicated that soil nitrate transported downwards, and obviously enriched in deeper soil layers under heavy application of fertilizer. Also with the increasing age of greenhouse field, soil pH decreased, while soil soluble salts accumulated. PMID:16471371

  17. Impacts of Salinity on Soil Hydraulic Properties and Evaporation Fluxes

    NASA Astrophysics Data System (ADS)

    Fierro, V.; Cristi Matte, F.; Suarez, F. I.; Munoz, J. F.

    2014-12-01

    Saline soils are common in arid zones, where evaporation from shallow groundwater is generally the main component of the water balance. Thus, to correctly manage water resources in these zones, it is important to quantify the evaporation fluxes. Evaporation from saline soils is a complex process that couples the movement of salts, heat, liquid water and water vapor, and strongly depends on the soil water content. Precipitation/dissolution reactions can change the soil structure and alter flow paths, modifying evaporation fluxes. We utilized the HYDRUS-1D model to investigate the effects of salinity on soil hydraulic properties and evaporation fluxes. HYDRUS-1D simulates the transport of liquid water, water vapor, and heat, and can incorporate precipitation/dissolution reactions of the major ions. To run the model, we determined the water retention curve for a soil with different salinities; and we used meteorological forcing from an experimental site from the Atacama Desert. It was found that higher sodium adsorption ratios in the soil increase the soil water retention capacity. Also, it was found that evaporation fluxes increase salts concentration near the soil surface, changing the soil's water retention capacity in that zone. Finally, movement of salts causes differences in evaporation fluxes. It is thus necessary to incorporate salt precipitation/dissolution reactions and its effects on the water retention curve to correctly simulate evaporation in saline soils

  18. Fly ash addition affects microbial biomass and carbon mineralization in agricultural soils.

    PubMed

    Nayak, A K; Kumar, Anjani; Raja, R; Rao, K S; Mohanty, Sangita; Shahid, Mohammad; Tripathy, Rahul; Panda, B B; Bhattacharyya, P

    2014-02-01

    The microbial biomass carbon (MBC) and carbon mineralization of fly ash (FA) amended soil at (0 %, 1.25 %, 2.5 %, 5 %, 10 % and 20 % FA; v/v) was investigated under laboratory conditions for 120 days at 60 % soil water-holding capacity and 25 ± 1°C temperature. The results demonstrated that soil respiration and microbial activities were not suppressed up to 2.5 % FA amendment and these activities decreased significantly at 10 % and 20 % FA treatment with respect to control. Application of 10 % and 20 % FA treated soils showed a decreasing trend of soil MBC with time; and the decrease was significant throughout the period of incubation. The study concluded that application of FA up to 2.5 % can thus be safely used without affecting the soil biological activity and thereby improve nutrient cycling in agricultural soils. PMID:24362819

  19. Microbial community composition as affected by dryland cropping systems and tillage in a semiarid sandy soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This study evaluated microbial communities of soil (0-10 cm) as affected by dryland cropping systems under different tillage practices after 5 years. The soil is an Olton sandy loam (Fine, mixed, superactive, thermic Aridic Paleustolls) with an average of 16.4% clay, 67.6% sand and 0.65 g kg-1 of O...

  20. Importance of soil-water relation in assessment endpoint in bioremediated soils: Plant growth and soil physical properties

    SciTech Connect

    Li, X.; Sawatsky, N.

    1995-12-31

    Much effort has been focused on defining the end-point of bioremediated soils by chemical analysis (Alberta Tier 1 or CCME Guideline for Contaminated Soils) or toxicity tests. However, these tests do not completely assess the soil quality, or the capability of soil to support plant growth after bioremediation. This study compared barley (Hordeum vulgare) growth on: (i) non-contaminated, agricultural topsoil, (2) oil-contaminated soil (4% total extractable hydrocarbons, or TEH), and (3) oil-contaminated soil treated by bioremediation (< 2% TEH). Soil physical properties including water retention, water uptake, and water repellence were measured. The results indicated that the growth of barley was significantly reduced by oil-contamination of agricultural topsoil. Furthermore, bioremediation did not improve the barley yield. The lack of effects from bioremediation was attributed to development of water repellence in hydrocarbon contaminated soils. There seemed to be a critical water content around 18% to 20% in contaminated soils. Above this value the water uptake by contaminated soil was near that of the agricultural topsoil. For lower water contents, there was a strong divergence in sorptivity between contaminated and agricultural topsoil. For these soils, water availability was likely the single most important parameter controlling plant growth. This parameter should be considered in assessing endpoint of bioremediation for hydrocarbon contaminated soils.

  1. Soil properties and not inputs control carbon : nitrogen : phosphorus ratios in cropped soils in the long term

    NASA Astrophysics Data System (ADS)

    Frossard, Emmanuel; Buchmann, Nina; Bünemann, Else K.; Kiba, Delwende I.; Lompo, François; Oberson, Astrid; Tamburini, Federica; Traoré, Ouakoltio Y. A.

    2016-02-01

    Stoichiometric approaches have been applied to understand the relationship between soil organic matter dynamics and biological nutrient transformations. However, very few studies have explicitly considered the effects of agricultural management practices on the soil C : N : P ratio. The aim of this study was to assess how different input types and rates would affect the C : N : P molar ratios of bulk soil, organic matter and microbial biomass in cropped soils in the long term. Thus, we analysed the C, N, and P inputs and budgets as well as soil properties in three long-term experiments established on different soil types: the Saria soil fertility trial (Burkina Faso), the Wagga Wagga rotation/stubble management/soil preparation trial (Australia), and the DOK (bio-Dynamic, bio-Organic, and "Konventionell") cropping system trial (Switzerland). In each of these trials, there was a large range of C, N, and P inputs which had a strong impact on element concentrations in soils. However, although C : N : P ratios of the inputs were highly variable, they had only weak effects on soil C : N : P ratios. At Saria, a positive correlation was found between the N : P ratio of inputs and microbial biomass, while no relation was observed between the nutrient ratios of inputs and soil organic matter. At Wagga Wagga, the C : P ratio of inputs was significantly correlated to total soil C : P, N : P, and C : N ratios, but had no impact on the elemental composition of microbial biomass. In the DOK trial, a positive correlation was found between the C budget and the C to organic P ratio in soils, while the nutrient ratios of inputs were not related to those in the microbial biomass. We argue that these responses are due to differences in soil properties among sites. At Saria, the soil is dominated by quartz and some kaolinite, has a coarse texture, a fragile structure, and a low nutrient content. Thus, microorganisms feed on inputs (plant residues, manure). In contrast, the soil at

  2. Effects of biochar and other amendments on the physical properties and greenhouse gas emissions of an artificially degraded soil.

    PubMed

    Mukherjee, A; Lal, R; Zimmerman, A R

    2014-07-15

    Short and long-term impacts of biochar on soil properties under field conditions are poorly understood. In addition, there is a lack of field reports of the impacts of biochar on soil physical properties, gaseous emissions and C stability, particularly in comparison with other amendments. Thus, three amendments - biochar produced from oak at 650°C, humic acid (HA) and water treatment residual - (WTR) were added to a scalped silty-loam soil @ 0.5% (w/w) in triplicated plots under soybean. Over the 4-month active growing season, all amendments significantly increased soil pH, but the effect of biochar was the greatest. Biochar significantly increased soil-C by 7%, increased sub-nanopore surface area by 15% and reduced soil bulk density by 13% compared to control. However, only WTR amendment significantly increased soil nanopore surface area by 23% relative to the control. While total cumulative CH4 and CO2 emissions were not significantly affected by any amendment, cumulative N2O emission was significantly decreased in the biochar-amended soil (by 92%) compared to control over the growing period. Considering both the total gas emissions and the C removed from the atmosphere as crop growth and C added to the soil, WTR and HA resulted in net soil C losses and biochar as a soil C gain. However, all amendments reduced the global warming potential (GWP) of the soil and biochar addition even produced a net negative GWP effect. The short observation period, low application rate and high intra-treatment variation resulted in fewer significant effects of the amendments on the physicochemical properties of the soils than one might expect indicating further possible experimentation altering these variables. However, there was clear evidence of amendment-soil interaction processes affecting both soil properties and gaseous emissions, particularly for biochar, that might lead to greater changes with additional field emplacement time. PMID:24751592

  3. Soil Diversity as Affected by Land Use in China: Consequences for Soil Protection

    PubMed Central

    Shangguan, Wei; Gong, Peng; Liang, Lu; Dai, YongJiu; Zhang, Keli

    2014-01-01

    Rapid land-use change in recent decades in China and its impact on terrestrial biodiversity have been widely studied, particularly at local and regional scales. However, the effect of land-use change on the diversity of soils that support the terrestrial biological system has rarely been studied. Here, we report the first effort to assess the impact of land-use change on soil diversity for the entire nation of China. Soil diversity and land-use effects were analyzed spatially in grids and provinces. The land-use effects on different soils were uneven. Anthropogenic soils occupied approximately 12% of the total soil area, which had already replaced the original natural soils. About 7.5% of the natural soil classes in China were in danger of substantial loss, due to the disturbance of agriculture and construction. More than 80% of the endangered soils were unprotected due to the overlook of soil diversity. The protection of soil diversity should be integrated into future conservation activities. PMID:25250394

  4. Hydraulic properties of saltstone and Z-Area soil

    SciTech Connect

    Cook, J.R.; Langton, C.A.; Wilhite, E.L.

    1986-04-04

    Basic hydraulic characteristics of disturbed and undisturbed Z-Area soil and of sandstone have been obtained. These data will aid modeling of the release of soluble ions from saltstone after disposal. Modeling of the release of soluble ions from saltstone and the migration of those materials to the water table has been underway for some time. Data needed for modeling were inferred from data available on burial ground soils and soils near Z-Area. To improve the accuracy of modeling, the hydraulic properties of Z-Area soil and saltstone were measured. A report is attached; results are summarized below. 7 refs., 7 figs. 1 tab.

  5. Survival of Manure-borne and Fecal Coliforms in Soil: Temperature Dependence as Affected by Site-Specific Factors.

    PubMed

    Park, Yongeun; Pachepsky, Yakov; Shelton, Daniel; Jeong, Jaehak; Whelan, Gene

    2016-05-01

    Understanding pathogenic and indicator bacteria survival in soils is essential for assessing the potential of microbial contamination of water and produce. The objective of this work was to evaluate the effects of soil properties, animal source, experimental conditions, and the application method on temperature dependencies of manure-borne generic , O157:H7, and fecal coliforms survival in soils. A literature search yielded 151 survival datasets from 70 publications. Either one-stage or two-stage kinetics was observed in the survival datasets. We used duration and rate of the logarithm of concentration change as parameters of the first stage in the two-stage kinetics data. The second stage of the two-stage kinetics and the one-stage kinetics were simulated with the model to find the dependence of the inactivation rate on temperature. Classification and regression trees and linear regressions were applied to parameterize the kinetics. Presence or absence of two-stage kinetics was controlled by temperature, soil texture, soil water content, and for fine-textured soils by setting experiments in the field or in the laboratory. The duration of the first stage was predominantly affected by soil water content and temperature. In the model dependencies of inactivation rates on temperature, parameter estimates were significantly affected by the laboratory versus field conditions and by the application method, whereas inactivation rates at 20°C were significantly affected by all survival and management factors. Results of this work can provide estimates of coliform survival parameters for models of microbial water quality. PMID:27136162

  6. Effects of Soil Property Uncertainty on Projected Active Layer Thickness

    NASA Astrophysics Data System (ADS)

    Harp, D. R.; Atchley, A. L.; Coon, E.; Painter, S. L.; Wilson, C. J.; Romanovsky, V. E.; Liljedahl, A.

    2014-12-01

    Uncertainty in future climate is often assumed to contribute the largest uncertainty to active layer thickness (ALT) projections. However, the impact of soil property uncertainty on these projections may be significant. In this research, we evaluate the contribution of soil property uncertainty on ALT projections at the Barrow Environmental Observatory, Alaska. The effect of variations in porosity, thermal conductivity, saturation, and water retention properties of peat and mineral soil are evaluated. The micro-topography of ice wedge polygons present at the site is included in the analysis using three 1D column models to represent polygon center, rim and trough features. The Arctic Terrestrial Simulator (ATS) is used to model multiphase thermal and hydrological processes in the subsurface. We apply the Null-Space Monte Carlo (NSMC) algorithm to identify an ensemble of soil property combinations that produce simulated temperature profiles that are consistent with temperature measurements available from the site. ALT is simulated for the ensemble of soil property combinations for four climate scenarios. The uncertainty in ALT due to soil properties within and across climate scenarios is evaluated. This work was supported by LANL Laboratory Directed Research and Development Project LDRD201200068DR and by the The Next-Generation Ecosystem Experiments (NGEE Arctic) project. NGEE-Arctic is supported by the Office of Biological and Environmental Research in the DOE Office of Science.

  7. Effects of spatial variability of soil hydraulic properties on water dynamics

    NASA Astrophysics Data System (ADS)

    Gumiere, Silvio Jose; Caron, Jean; Périard, Yann; Lafond, Jonathan

    2013-04-01

    Soil hydraulic properties may present spatial variability and dependence at the scale of watersheds or fields even in man-made single soil structures, such as cranberry fields. The saturated hydraulic conductivity (Ksat) and soil moisture curves were measured at two depths for three cranberry fields (about 2 ha) at three different sites near Québec city, Canada. Two of the three studied fields indicate strong spatial dependence for Ksat values and soil moisture curves both in horizontal and vertical directions. In the summer of 2012, the three fields were equipped with 55 tensiometers installed at a depth of 0.10 m in a regular grid. About 20 mm of irrigation water were applied uniformly by aspersion to the fields, raising soil water content to near saturation condition. Soil water tension was measured once every hour during seven days. Geostatistical techniques such as co-kriging and cross-correlograms estimations were used to investigate the spatial dependence between variables. The results show that soil tension varied faster in high Ksat zones than in low Ksatones in the cranberry fields. These results indicate that soil water dynamic is strongly affected by the variability of saturated soil hydraulic conductivity, even in a supposed homogenous anthropogenic soil. This information may have a strong impact in irrigation management and subsurface drainage efficiency as well as other water conservation issues. Future work will involve 3D numerical modeling of the field water dynamics with HYDRUS software. The anticipated outcome will provide valuable information for the understanding of the effect of spatial variability of soil hydraulic properties on soil water dynamics and its relationship with crop production and water conservation.

  8. Properties of hydrocarbon- and salt-contaminated flare pit soils in northeastern British Columbia (Canada).

    PubMed

    Arocena, J M; Rutherford, P M

    2005-07-01

    Many contaminated sites in Canada are associated with flare pits generated during past petroleum extraction operations. Flare pits are located adjacent to well sites, compressor stations and batteries and are often subjected to the disposal of wastes from the flaring of gas, liquid hydrocarbons and brine water. This study was conducted to evaluate the physical, chemical, electrical and mineral properties of three flare pit soils as compared to adjacent control soils. Results showed that particle size distribution, pH, total N, cation exchange capacity, exchangeable Mg(2+), and sodium adsorption ratio were similar in soils from flare pits and control sites. Total C, exchangeable Ca(2+), K(+) and Na(+), soluble Ca(2+), Mg(2+), K(+) and Na(+) and electrical conductivity were higher in flare pit soils compared to control soils. X-ray diffraction and scanning electron microscopic analyses showed the presence of gypsum [CaSO(4).2H(2)O], dolomite [CaMg(CO(3))(2)], pyrite [FeS(2)], jarosite [KFe(3)(OH)(6)(SO(4))(2)], magnesium sulphate, oxides of copper and iron+copper in salt efflorescence observed in flare pit soils. Soils from both flare pits and control sites contained mica, kaolonite and 2:1 expanding clays. The salt-rich materials altered the ionic equilibria in the flare pit soils; K(Mg-Ca) selectivity coefficients in control soils were higher compared to contaminated soils. The properties of soils (e.g., high electrical conductivity) affected by inputs associated with oil and gas operations might render flare pit soils less conducive to the establishment and growth of common agricultural crops and forest trees. PMID:15950049

  9. Soil biochemical properties after six years in amended brown and gray mine soils in West Virginia

    NASA Astrophysics Data System (ADS)

    Thomas, C.; Sexstone, A.; Skousen, J.

    2015-06-01

    Surface coal mining in the eastern USA disturbs hundreds of hectares of land every year and removes valuable and ecologically diverse eastern deciduous forests. Reclamation involves restoring the landscape to approximate original contour, replacing the topsoil, and revegetating the site with trees and herbaceous species to a designated post-mining land use. Re-establishing an ecosystem of ecological and economic value as well as restoring soil quality on disturbed sites are the goals of land reclamation, and microbial properties of mine soils can be indicators of restoration success. Reforestation plots were constructed in 2007 using weathered brown sandstone or unweathered gray sandstone as topsoil substitutes to evaluate tree growth and soil properties at Arch Coal's Birch River Mine in West Virginia, USA. All plots were planted with 12 hardwood tree species and subplots were hydroseeded with an herbaceous seed mix and fertilizer. After six years, average tree volume index was nearly ten times greater for trees grown in brown (3853 cm3) compared to gray mine soils (407 cm3). Average pH of brown mine soils increased from 4.7 to 5.0, while gray mine soils declined from 7.9 to 7.0. Hydroseeding doubled tree volume index and ground cover on both mine soils. Hydroseeding doubled microbial biomass carbon (MBC) on brown mine soils (8.7 vs. 17.5 mg kg-1), but showed no effect on gray (13.3 vs. 12.8 mg kg-1). Hydroseeding also increased the ratio of MBC to soil organic C in both soils and more than tripled the ratio for potentially mineralizable nitrogen (PMN) to total N. Brown mine soils were a better growth medium than gray mine soils and hydroseeding was an important component of reclamation due to improved biochemical properties and microbial activity in mine soils.

  10. Seasonal Dynamics of Trace Elements in Tidal Salt Marsh Soils as Affected by the Flow-Sediment Regulation Regime

    PubMed Central

    Bai, Junhong; Xiao, Rong; Zhao, Qingqing; Lu, Qiongqiong; Wang, Junjing; Reddy, K. Ramesh

    2014-01-01

    Soil profiles were collected in three salt marshes with different plant species (i.e. Phragmites australis, Tamarix chinensis and Suaeda salsa) in the Yellow River Delta (YRD) of China during three seasons (summer and fall of 2007 and the following spring of 2008) after the flow-sediment regulation regime. Total elemental contents of As, Cd, Cu, Pb and Zn were determined using inductively coupled plasma atomic absorption spectrometry to investigate temporal variations in trace elements in soil profiles of the three salt marshes, assess the enrichment levels and ecological risks of these trace elements in three sampling seasons and identify their influencing factors. Trace elements did not change significantly along soil profiles at each site in each sampling season. The highest value for each sampling site was observed in summer and the lowest one in fall. Soils in both P. australis and S. salsa wetlands tended to have higher trace element levels than those in T. chinensis wetland. Compared to other elements, both Cd and As had higher enrichment factors exceeding moderate enrichment levels. However, the toxic unit (TU) values of these trace elements did not exceed probable effect levels. Correlation analysis showed that these trace elements were closely linked to soil properties such as moisture, sulfur, salinity, soil organic matter, soil texture and pH values. Principal component analysis showed that the sampling season affected by the flow-sediment regulation regime was the dominant factor influencing the distribution patterns of these trace elements in soils, and plant community type was another important factor. The findings of this study could contribute to wetland conservation and management in coastal regions affected by the hydrological engineering. PMID:25216278

  11. Long-term toxicity assessment of soils in a recovered area affected by a mining spill.

    PubMed

    Romero-Freire, A; García Fernández, I; Simón Torres, M; Martínez Garzón, F J; Martín Peinado, F J

    2016-01-01

    Residual pollution in the Guadiamar Green Corridor still remains after Aználcollar mine spill in 1998. The polluted areas are identified by the absence of vegetation, soil acidic pH and high concentrations of As, Pb, Zn and Cu. Soil toxicity was assessed by lettuce root elongation and induced soil respiration bioassays. In bare soils, total As and Pb concentrations and water-extractable levels for As, Zn and Cu exceeded the toxicity guidelines. Pollutants responsible for toxicity were different depending on the tested organism, with arsenic being most toxic for lettuce and the metal mixture to soil respiration. Soil properties, such as pH or organic carbon content, are key factors to control metal availability and toxicity in the area. According to our results, there is a risk of pollution to living organisms and the soil quality criteria established in the area should be revised to reduce the risk of toxicity. PMID:26608875

  12. Soil enzyme activities as affected by anthropogenic alterations: intensive agricultural practices and organic pollution.

    PubMed

    Gianfreda, Liliana; Antonietta Rao, Maria; Piotrowska, Anna; Palumbo, Giuseppe; Colombo, Claudio

    2005-04-01

    The activity of a range of enzymes related to the cycling of the main biologically important nutrients C, N, P and S was investigated in cultivated and non-cultivated soils from various parts of Europe. Two agricultural sites from North Italy under continuous corn (Zea mays L.) with and without organic fertilization were compared. Two other agricultural sites from South Italy under hazel (Corylus avellana L.) never flooded or repeatedly flooded over by uncontrolled urban and industrial wastes were investigated. The non-cultivated soils were from Middle and South Europe with different pollution history such as no-pollution and pollution with organic contaminants, which is phenanthrene and other polycyclic aromatic hydrocarbons (PAHs). Agricultural soils showed significant differences in some of physical-chemical properties (i.e. organic C, total and labile phosphate contents, available Ca and Mg) between the two sites studied. Enzyme activities of hazel sites periodically flooded by wastes were mainly higher than in the hazel sites never flooded. Sites under many years of continuous corn showed dehydrogenase, invertase, arylsulphatase and beta-glucosidase activities generally lower than the soils under hazel either flooded or not by wastes. As compared to agricultural soils, non-cultivated soils heavily or moderately polluted by organic contaminants displayed much lower values or complete absence of enzymatic activities. Dissimilar, contradictory correlations between soil enzyme activities and the majority of soil properties were observed separately in the two groups of soils. When the whole set of enzyme activities and soil properties were considered, all significant correlations found separately for the groups of soils were lost. The overall results seem to confirm that no direct cause-effect relationships can be derived between the changes of a soil in response to a given factor and both the variations of the activity and the behaviour of the enzymes in soil

  13. Mapping of Soil Properties Using Hyperspectral Remote Sensing

    NASA Astrophysics Data System (ADS)

    Dutta, D.; Goodwell, A. E.; Greenberg, J. A.; Kumar, P.; Darmody, R. G.; Garvey, J. E.; Jacobson, R. B.; Beretta, D. P.

    2013-12-01

    This study presents a novel framework for the quantification of surface soil properties over very large areas and at a very high spatial resolution using high resolution imaging spectroscopy from airborne sensors. The Airborne Visible Infrared Imaging Spectrometer (AVIRIS) data collected by NASA immediately after the massive 2011 Mississippi floods at the Birds Point New Madrid (BPNM) floodway was used for quantitative prediction of soil surface textural properties such as percentages of sand, silt and clay and a suit of other chemical properties such as Mg, Al, Ca, K, Cu, P, Mn, Soil Organic Matter, S, B, Fe and Zn. The visible, near infrared and shortwave infrared region of the AVIRIS reflectance spectrum was used together with an automatic variable selection lasso algorithm to yield empirical models for the prediction of various soil properties using a set of field soil sample data which were analyzed in the laboratory for calibration of the models. The linear modeling framework was made rigorous by using an ensemble of bootstrapping techniques for selecting the set of predictors and determining the final model coefficients. The modeling results not only revealed the feasibility of quantifying the different properties using this approach but also showed that some of these properties can be predicted with high accuracy. The prediction models were further used for a pixel by pixel quantification of the soil properties resulting in maps showing the spatial extents over large areas of each of the properties in the entire BPNM floodway. The fine spatial resolution of 7.6m of these maps also revealed many interesting spatial patterns and correlations with the underlying topography immediately disturbed by a massive flooding event. This study employs hyperspectral remote sensing for the quantification of soil properties using AVIRIS data and examines the signatures of disasters such as floods on landscapes which has not been explored previously and paves the way for

  14. Effect of selected soil conditioners on soil properties, erosion, runoff, and rye growth in nonfertile acid soil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Construction operations result in highly disturbed soil, vulnerable to erosion and excess runoff and sediment loads. Limited information exists about effects of erosion mitigation practices on soil and runoff properties in low fertility acidic sites. The current study evaluates the use of polyacry...

  15. High Strength Stainless Steel Properties that Affect Resistance Welding

    SciTech Connect

    Kanne, W.R.

    2001-08-01

    This report discusses results of a study on selected high strength stainless steel alloy properties that affect resistance welding. The austenitic alloys A-286, JBK-75 (Modified A-286), 21-6-9, 22-13-5, 316 and 304L were investigated and compared. The former two are age hardenable, and the latter four obtain their strength through work hardening. Properties investigated include corrosion and its relationship to chemical cleaning, the effects of heat treatment on strength and surface condition, and the effect of mechanical properties on strength and weldability.

  16. Links among nitrification, nitrifier communities, and edaphic properties in contrasting soils receiving dairy slurry.

    PubMed

    Fortuna, Ann-Marie; Honeycutt, C Wayne; Vandemark, George; Griffin, Timothy S; Larkin, Robert P; He, Zhongqi; Wienhold, Brian J; Sistani, Karamat R; Albrecht, Stephan L; Woodbury, Bryan L; Torbert, Henry A; Powell, J Mark; Hubbard, Robert K; Eigenberg, Roger A; Wright, Robert J; Alldredge, J Richard; Harsh, James B

    2012-01-01

    Soil biotic and abiotic factors strongly influence nitrogen (N) availability and increases in nitrification rates associated with the application of manure. In this study, we examine the effects of edaphic properties and a dairy (Bos taurus) slurry amendment on N availability, nitrification rates and nitrifier communities. Soils of variable texture and clay mineralogy were collected from six USDA-ARS research sites and incubated for 28 d with and without dairy slurry applied at a rate of ~300 kg N ha(-1). Periodically, subsamples were removed for analyses of 2 M KCl extractable N and nitrification potential, as well as gene copy numbers of ammonia-oxidizing bacteria (AOB) and archaea (AOA). Spearman coefficients for nitrification potentials and AOB copy number were positively correlated with total soil C, total soil N, cation exchange capacity, and clay mineralogy in treatments with and without slurry application. Our data show that the quantity and type of clay minerals present in a soil affect nitrifier populations, nitrification rates, and the release of inorganic N. Nitrogen mineralization, nitrification potentials, and edaphic properties were positively correlated with AOB gene copy numbers. On average, AOA gene copy numbers were an order of magnitude lower than those of AOB across the six soils and did not increase with slurry application. Our research suggests that the two nitrifier communities overlap but have different optimum environmental conditions for growth and activity that are partly determined by the interaction of manure-derived ammonium with soil properties. PMID:22218194

  17. Climatic controls on soil hydraulic properties along soil chronosequences on volcanic parent material

    NASA Astrophysics Data System (ADS)

    Beal, L. K.; Lohse, K. A.; Godsey, S.; Huber, D. P.

    2013-12-01

    Soil development is influenced by physical and chemical weathering processes and accumulation of eolian sediment. These weathering processes have often been examined using chronosequences that take advantage of deposited lava flows ranging in age. These studies typically characterize the physical and sometimes chemical properties, but rarely have these studies examined how hydraulic properties change with time. In addition, many of these studies occur in tropical climates where weathering occurs rapidly; relatively little is known about weathering processes in cool dry climates. This is important not only to understand how water and energy move in these water limited systems, but also to understand how they might change as climate patterns shift. The objectives of this research were to 1) measure and model the soil water retention, θ(h), and hydraulic conductivity, K(h), functions across a chronosequence of cinder cone sites in a cold desert region, 2) compare soil hydraulic properties across soil ages to examine how soil development in semi-arid climates moderates soil hydraulic processes, and 3) compare soil hydraulic characteristics in a dryland environment to those of a wet tropical climate across similarly aged lava flows. We contrast 2.1, 6.9 and 13.9 ka cinder cones soils at Craters of the Moon (COTM) National Monument, Idaho, USA. Soil development at COTM is sparse and is concentrated in joints and crevices of the basalt. The soils contrast slightly in texture with age. The young (2.1 ka) soils are coarser grained with at least 20% greater sand content than the older (6.9, 13.9 ka) soils. Preliminary hydraulic modeling suggests that older soils have lower θ values than younger soils. This is likely due to a higher bulk density values from higher accumulations of secondary minerals in the old soils from loess input. The models show that the air entry points (α) occur at lower tensions in the young soils, likely caused by a greater pore size distribution

  18. Experimental determination of thermal properties of alluvial soil

    NASA Astrophysics Data System (ADS)

    Kulkarni, N. G.; Bhandarkar, U. V.; Puranik, B. P.; Rao, A. B.

    2016-02-01

    In the present work, thermal conductivity and specific heat of a particular type of alluvial soil used in brick making in a certain region of India (Karad, Maharashtra State) are experimentally determined for later use in the estimation of ground heat loss in clamp type kilns. These properties are determined simultaneously using the steady-state and the transient temperature data measured in the setup constructed for this purpose. Additionally, physical properties of the soil are experimentally determined for use with six models for the prediction of the thermal conductivity of soil. The predictions from the models are compared with the experimental data. A separate data fitting exercise revealed a small temperature dependence of the soil thermal conductivity on the soil mean temperature.

  19. Effects of poultry manure on soil biochemical properties in phthalic acid esters contaminated soil.

    PubMed

    Gao, Jun; Qin, Xiaojian; Ren, Xuqin; Zhou, Haifeng

    2015-12-01

    This study aimed to evaluate the effects of poultry manure (PM) on soil biological properties in DBP- and DEHP-contaminated soils. An indoor incubation experiment was conducted. Soil microbial biomass C (Cmic), soil enzymatic activities, and microbial phospholipid fatty acid (PLFA) concentrations were measured during incubation period. The results indicated that except alkaline phosphatase activity, DBP and DEHP had negative effects on Cmic, dehydrogenase, urease, protease activities, and contents of total PLFA. However, 5 % PM treatment alleviated the negative effects of PAEs on the above biochemical parameters. In DBP-contaminated soil, 5 % PM amendment even resulted in dehydroenase activity and Cmic content increasing by 17.8 and 11.8 % on the day 15 of incubation, respectively. During the incubation periods, the total PLFA contents decreased maximumly by 17.2 and 11.6 % in DBP- and DEHP-contaminated soils without PM amendments, respectively. Compared with those in uncontaminated soil, the total PLFA contents increased slightly and the value of bacPLFA/fugalPLFA increased significantly in PAE-contaminated soils with 5 % PM amendment. Nevertheless, in both contaminated soils, the effects of 5 % PM amendment on the biochemical parameters were not observed with 10 % PM amendment. In 10 % PM-amended soils, DBP and DEHP had little effect on Cmic, soil enzymatic activities, and microbial community composition. At the end of incubation, the effects of PAEs on these parameters disappeared, irrespective of PM amendment. The application of PM ameliorated the negative effect of PAEs on soil biological environment. However, further work is needed to study the effect of PM on soil microbial gene expression in order to explain the change mechanisms of soil biological properties. PMID:26298343

  20. 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 5 years reduced wind and water erosion, increased soil organic carbon (SOC), and ...

  1. 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...

  2. Litter and soil properties are not altered by invasive deer browsing in forests of NW Patagonia

    NASA Astrophysics Data System (ADS)

    Relva, María Andrea; Castán, Elisa; Mazzarino, María Julia

    2014-01-01

    It is largely accepted that large mammalian herbivores can indirectly influence ecosystem properties by changing the quantity and quality of litter inputs to soil through selective browsing on plant communities. However, idiosyncratic effects (positive, neutral and negative) have been found for different vegetation types, herbivory and soil properties. In this study we tested whether browsing by exotic deer introduced into Patagonian forests 90 years ago alters physical, chemical and biological soil properties and litter quantity and quality. As in many terrestrial ecosystems, N is the main nutrient that limits plant growth in Patagonia. Consequently, any disturbance that alters the N cycle, such as changes in the type or intensity of herbivory, is expected to affect these forest ecosystems. We compared soil and total litter from inside and outside five 7-yr old exclosures located on Isla Victoria, Parque Nacional Nahuel Huapi, Argentina. Despite introduced deer has significantly affected the composition, abundance and structure of the understory vegetation, we found no differences between browsed and unbrowsed areas in the physical (bulk density, moisture), chemical (pH, base cations, organic C and total N) and biological (potential microbial respiration and net N mineralization) soil properties. This could be attributable to the high capacity of volcanic soils to stabilize organic matter, buffering disturbance-induced changes. However, the quantity and quality (C, N and C/N ratio) of total litter were also not different between browsed and unbrowsed areas. Although non-significant differences were found between treatments in both compartments, litter and soil, most variables showed a slight trend toward higher values in unbrowsed areas. This suggests that 7 years of browsing exclusion would be not enough to detect changes induced by browsing, particularly in highly stable volcanic soils.

  3. Affects of different tillage managements on soil physical quality in a clayey soil.

    PubMed

    Sağlam, Mustafa; Selvi, Kemal Çağatay; Dengiz, Orhan; Gürsoy, Fatma Esra

    2015-01-01

    This study, conducted in 2011, researches the effects of different tillage practices on the physical soil quality of clayey soil. This soil quality index (SQI) assessment was made by studying the changes in physical soil functions such as suitability for root development, facilitation for water entry, movement and storage, and resistance against surface degradation based on tillage management. When compared with the control parcel, statistically significant decreases were seen in the SQI with different tillage practices (p < 0.05). Among the tillage practices, the highest SQI was seen with the plow + rotary tiller + direct seeding machine, while the lowest SQI was seen with the direct drilling practice. On the other hand, the statistically insignificant effects of tillage practices on the soil quality of the study area were considered to be a result of either the study period or the joint effect of soil texture and climatic features. Thus, long-term tillage practices were recommended in order to get healthier information about soil quality by considering soil and climatic conditions. In addition, for heavy clayey soils, reduced tillage practices, which included plowing, were thought to develop physical soil qualities of root development and water movement. PMID:25467416

  4. 7 CFR 1955.105 - Real property affected (CONACT).

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 14 2011-01-01 2011-01-01 false Real property affected (CONACT). 1955.105 Section 1955.105 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS-COOPERATIVE SERVICE, RURAL UTILITIES SERVICE, AND FARM SERVICE AGENCY, DEPARTMENT OF AGRICULTURE (CONTINUED) PROGRAM REGULATIONS...

  5. 7 CFR 1955.105 - Real property affected (CONACT).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 14 2010-01-01 2009-01-01 true Real property affected (CONACT). 1955.105 Section 1955.105 Agriculture Regulations of the Department of Agriculture (Continued) RURAL HOUSING SERVICE, RURAL BUSINESS-COOPERATIVE SERVICE, RURAL UTILITIES SERVICE, AND FARM SERVICE AGENCY, DEPARTMENT OF AGRICULTURE (CONTINUED) PROGRAM REGULATIONS...

  6. USING ENSEMBLE PREDICTIONS TO SIMULATE FIELD-SCALE SOIL WATER TIME SERIES WITH UPSCALED AND DOWNSCALED SOIL HYDRAULIC PROPERTIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Simulations of soil water flow require measurements of soil hydraulic properties which are particularly difficult at field scale. Laboratory measurements provide hydraulic properties at scales finer than the field scale, whereas pedotransfer functions (PTFs) integrate information on hydraulic prope...

  7. Estimation of soil hydraulic properties with microwave techniques

    NASA Technical Reports Server (NTRS)

    Oneill, P. E.; Gurney, R. J.; Camillo, P. J.

    1985-01-01

    Useful quantitative information about soil properties may be obtained by calibrating energy and moisture balance models with remotely sensed data. A soil physics model solves heat and moisture flux equations in the soil profile and is driven by the surface energy balance. Model generated surface temperature and soil moisture and temperature profiles are then used in a microwave emission model to predict the soil brightness temperature. The model hydraulic parameters are varied until the predicted temperatures agree with the remotely sensed values. This method is used to estimate values for saturated hydraulic conductivity, saturated matrix potential, and a soil texture parameter. The conductivity agreed well with a value measured with an infiltration ring and the other parameters agreed with values in the literature.

  8. Dielectric properties of soils as a function of moisture content

    NASA Technical Reports Server (NTRS)

    Cihlar, J.; Ulaby, F. T.

    1974-01-01

    Soil dielectric constant measurements are reviewed and the dependence of the dielectric constant on various soil parameters is determined. Moisture content is given special attention because of its practical significance in remote sensing and because it represents the single most influential parameter as far as soil dielectric properties are concerned. Relative complex dielectric constant curves are derived as a function of volumetric soil water content at three frequencies (1.3 GHz, 4.0 GHz, and 10.0 GHz) for each of three soil textures (sand, loam, and clay). These curves, presented in both tabular and graphical form, were chosen as representative of the reported experimental data. Calculations based on these curves showed that the power reflection coefficient and emissivity, unlike skin depth, vary only slightly as a function of frequency and soil texture.

  9. Landscape position moderates how ant nests affect hydrology and soil chemistry across a Chihuahuan Desert watershed

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ants moderate the supply of critical resources such as water and nutrients in desert environments by changing the physical arrangement of soils during nest construction. We measured water infiltration and soil physical and chemical properties on and off the nests of two ant species (Pogonomyrmex rug...

  10. Water and salt extractable organic matter as affected by soil depth and tillage system

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soluble organic matter (OM) has been suggested to reflect shifts in soil management. We characterized the pool size and properties of soluble OM along a soil profile to 125 cm in a maize-based agricultural system that was managed under conventional tillage (CT) and no-tillage (NT) systems for 23 yea...

  11. Soil properties discriminating Araucaria forests with different disturbance levels.

    PubMed

    Bertini, Simone Cristina Braga; Azevedo, Lucas Carvalho Basilio; Stromberger, Mary E; Cardoso, Elke Jurandy Bran Nogueira

    2015-04-01

    Soil biological, chemical, and physical properties can be important for monitoring soil quality under one of the most spectacular vegetation formation on Atlantic Forest Biome, the Araucaria Forest. Our aim was to identify a set of soil variables capable of discriminating between disturbed, reforested, and native Araucaria forest soils such that these variables could be used to monitor forest recovery and maintenance. Soil samples were collected at dry and rainy season under the three forest types in two state parks at São Paulo State, Brazil. Soil biological, chemical, and physical properties were evaluated to verify their potential to differentiate the forest types, and discriminant analysis was performed to identify the variables that most contribute to the differentiation. Most of physical and chemical variables were sensitive to forest disturbance level, but few biological variables were significantly different when comparing native, reforested, and disturbed forests. Despite more than 20 years following reforestation, the reforested soils were chemically and biologically distinct from native and disturbed forest soils, mainly because of the greater acidity and Al3+ content of reforested soil. Disturbed soils, in contrast, were coarser in texture and contained greater concentrations of extractable P. Although biological properties are generally highly sensitive to disturbance and amelioration efforts, the most important soil variables to discriminate forest types in both seasons included Al3+, Mg2+, P, and sand, and only one microbial attribute: the NO2- oxidizers. Therefore, these five variables were the best candidates, of the variables we employed, for monitoring Araucaria forest disturbance and recovery. PMID:25792021

  12. Impact of the post fire management in some soil chemical properties. First results.

    NASA Astrophysics Data System (ADS)

    Francos, Marcos; Pereira, Paulo; Alcañiz, Meritxell; Úbeda, Xavi

    2016-04-01

    Post-fire management after severe wildfires has impact on soil properties. In Mediterranean environments management of fire affected areas is a common practice. This intervention may change soil chemical properties of the soil such as major cations. The aim of this work is to study the impact of different types of forest management in soil extractable calcium, magnesium, sodium and potassium after a severe wildfire. The study area is located in Ódena (Catalonia, Spain). The wildfire occurred at July 27th of 2015 and burned 1235 ha. After the fire an experimental plot was designed 9 plots with 2x2 meters (4 square meters). The different managements were: a) clear-cuted area and wood removed, b) no treatment); and c) clear-cutted. The results of the first sampling showed significant differences among all treatments in extractable calcium, sodium and potassium. The amount of these extractable elements was high in clear-cutted treatment in comparison to the others. No differences were identified in extractable magnesium. Overall, in the immediate period after the fire, burned area management, changed the studied soil properties. We are currently studying the evolution of this soil properties in these plots with the time

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

    NASA Astrophysics Data System (ADS)

    Pigareva, Tatiana

    2015-04-01

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

  14. Visible-infrared properties of controlled laboratory soils

    NASA Technical Reports Server (NTRS)

    Pieters, C. M.; Mustard, J. F.; Pratt, S. F.; Sunshine, J. M.; Hoppin, Andrew

    1993-01-01

    Almost all surfaces available for remote observation consist of particulate materials or soils. The distribution of mean particle sizes depend on the original material and physical and chemical processes that have acted on the surface over time. It is well known that the optical and infrared spectral properties of materials depends on the particle size. There has been little detailed study, however, of natural soils, namely particulate materials with a range of particle sizes. Current models for intimate mixing typically use an average particle size in calculations and are most successful when the particle size is constrained by known sieve fractions. Preliminary results of a study in which soils were prepared with a known composition and range of particle sizes are reported. This discussion presents the overall visible to infrared properties of these synthetic soils and evaluates the mid-infrared properties.

  15. 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.

  16. Soil property maps of Africa at 250 m resolution

    NASA Astrophysics Data System (ADS)

    Kempen, Bas; Hengl, Tomislav; Heuvelink, Gerard B. M.; Leenaars, Johan G. B.; Walsh, Markus G.; MacMillan, Robert A.; Mendes de Jesus, Jorge S.; Shepherd, Keith; Sila, Andrew; Desta, Lulseged T.; Tondoh, Jérôme E.

    2015-04-01

    Vast areas of arable land in sub-Saharan Africa suffer from low soil fertility and physical soil constraints, and significant amounts of nutrients are lost yearly due to unsustainable soil management practices. At the same time it is expected that agriculture in Africa must intensify to meet the growing demand for food and fiber the next decades. Protection and sustainable management of Africa's soil resources is crucial to achieve this. In this context, comprehensive, accurate and up-to-date soil information is an essential input to any agricultural or environmental management or policy and decision-making model. In Africa, detailed soil information has been fragmented and limited to specific zones of interest for decades. To help bridge the soil information gap in Africa, the Africa Soil Information Service (AfSIS) project was established in 2008. AfSIS builds on recent advances in digital soil mapping, infrared spectroscopy, remote sensing, (geo)statistics, and integrated soil fertility management to improve the way soils are evaluated, mapped, and monitored. Over the period 2008-2014, the AfSIS project has compiled two soil profile data sets (about 28,000 unique locations): the Africa Soil Profiles (legacy) database and the AfSIS Sentinel Site (new soil samples) database -- the two data sets represent the most comprehensive soil sample database of the African continent to date. In addition a large set of high-resolution environmental data layers (covariates) was assembled. The point data were used in the AfSIS project to generate a set of maps of key soil properties for the African continent at 250 m spatial resolution: sand, silt and clay fractions, bulk density, organic carbon, total nitrogen, pH, cation-exchange capacity, exchangeable bases (Ca, K, Mg, Na), exchangeable acidity, and Al content. These properties were mapped for six depth intervals up to 2 m: 0-5 cm, 5-15 cm, 15-30 cm, 30-60 cm, 60-100 cm, and 100-200 cm. Random forests modelling was used to

  17. Sorption interactions of organic compounds with soils affected by agricultural olive mill wastewater.

    PubMed

    Keren, Yonatan; Borisover, Mikhail; Bukhanovsky, Nadezhda

    2015-11-01

    The organic compound-soil interactions may be strongly influenced by changes in soil organic matter (OM) which affects the environmental fate of multiple organic pollutants. The soil OM changes may be caused by land disposal of various OM-containing wastes. One unique type of OM-rich waste is olive mill-related wastewater (OMW) characterized by high levels of OM, the presence of fatty aliphatics and polyphenolic aromatics. The systematic data on effects of the land-applied OMW on organic compound-soil interactions is lacking. Therefore, aqueous sorption of simazine and diuron, two herbicides, was examined in batch experiments onto three soils, including untreated and OMW-affected samples. Typically, the organic compound-soil interactions increased following the prior land application of OMW. This increase is associated with the changes in sorption mechanisms and cannot be attributed solely to the increase in soil organic carbon content. A novel observation is that the OMW application changes the soil-sorbent matrix in such a way that the solute uptake may become cooperative or the existing ability of a soil sorbent to cooperatively sorb organic molecules from water may become characterized by a larger affinity. The remarkable finding of this study was that in some cases a cooperative uptake of organic molecules by soils makes itself evident in distinct sigmoidal sorption isotherms rarely observed in soil sorption of non-ionized organic compounds; the cooperative herbicide-soil interactions may be characterized by the Hill model coefficients. However, no single trend was found for the effect of applied OMW on the mechanisms of organic compound-soil interactions. PMID:26183941

  18. Correlation between structural diversity and catabolic versatility of metal-affected bacteria in soil

    NASA Astrophysics Data System (ADS)

    Wenderoth, D. F.; Reber, H. H.; Timmis, K. N.

    2003-04-01

    Application of sewage sludge to an agricultural field resulted in contamination of metal. Metal affects on the the structural diversity and the catabolic versatility of bacteria capable of growing in the absence of growing factors were studied six years after sludge application. The number of strain clusters as estimated by amplified ribosomal restriction analysis (ADRDA) was reduced by 39% when comparing isolates from the control and the most contaminated soil. Concomittantly, the average number of aromatic acids utilized per isolate from among 21 substrates tested decreased from 12.28 to 5.23. This loss in catabolic versatility was greater in Gram-negative (68%) than in Gram-positive bacteria (49%). Due to bioenergetic reasons discussed, it is supposed that the catabolic versatility between Gram-negative and Gram-positive bacteria and the greater loss of this property in the former may explain why, in metal contaminated soils, Grtam-negatives are selected at the expense of Gram-positive bacteria.

  19. Physicochemical and biological quality of soil in hexavalent chromium-contaminated soils as affected by chemical and microbial remediation.

    PubMed

    Liao, Yingping; Min, Xiaobo; Yang, Zhihui; Chai, Liyuan; Zhang, Shujuan; Wang, Yangyang

    2014-01-01

    Chemical and microbial methods are the main remediation technologies for chromium-contaminated soil. These technologies have progressed rapidly in recent years; however, there is still a lack of methods for evaluating the chemical and biological quality of soil after different remediation technologies have been applied. In this paper, microbial remediation with indigenous bacteria and chemical remediation with ferrous sulphate were used for the remediation of soils contaminated with Cr(VI) at two levels (80 and 1,276 mg kg(-1)) through a column leaching experiment. After microbial remediation with indigenous bacteria, the average concentration of water-soluble Cr(VI) in the soils was reduced to less than 5.0 mg kg(-1). Soil quality was evaluated based on 11 soil properties and the fuzzy comprehensive assessment method, including fuzzy mathematics and correlative analysis. The chemical fertility quality index was improved by one grade using microbial remediation with indigenous bacteria, and the biological fertility quality index increased by at least a factor of 6. Chemical remediation with ferrous sulphate, however, resulted in lower levels of available phosphorus, dehydrogenase, catalase and polyphenol oxidase. The result showed that microbial remediation with indigenous bacteria was more effective for remedying Cr(VI)-contaminated soils with high pH value than chemical remediation with ferrous sulphate. In addition, the fuzzy comprehensive evaluation method was proven to be a useful tool for monitoring the quality change in chromium-contaminated soils. PMID:23784058

  20. Effect of biofilm on soil hydraulic properties: laboratory studies using xanthan as surrogate

    NASA Astrophysics Data System (ADS)

    Rosenkranz, H.; Iden, S. C.; Durner, W.

    2012-04-01

    Many soil bacteria produce extracellular polymeric substances (EPS) in which they are embedded while residing in the porous matrix. EPS are often attached as a biofilm to both the bacteria cell and the soil particles. As a consequence, their influence on water flow through variably saturated porous media often cannot be neglected. While the influence of attached microbial biomass and EPS on saturated water flow has been studied extensively, its investigation for unsaturated flow in soils has found significantly less attention. The objective of this study was the quantification of the effect of biofilms on the unsaturated soil hydraulic properties. We determined the soil water retention and unsaturated hydraulic conductivity functions of biofilm-affected soils by using xanthan as an EPS surrogate. Evaporation experiments were conducted on two sandy soil materials. The amount of added xanthan was varied in 6 stages from zero to 0.25 %. Additional measurements of soil water retention using the dewpoint method closed the remaining gap from the evaporation method to air-dryness. The experimental data were evaluated by the simplified evaporation method of Schindler. The results show that the unsaturated hydraulic conductivity is reduced markedly by added xanthan and the shape of the soil water retention curve is alterated significantly for all stages of xanthan addition. The reduction in hydraulic conductivity is high enough to fully suppress stage-one evaporation for xanthan-sand mixtures. The water-holding capacity of the xanthan and the alteration of the effective pore size distribution explain these results.

  1. Effects of Mulching on Soil Properties and Growth of Tea Olive (Osmanthus fragrans)

    PubMed Central

    Ni, Xue; Song, Weiting; Zhang, Huanchao; Yang, Xiulian; Wang, Lianggui

    2016-01-01

    Different mulches have variable effects on soil physical properties and plant growth. This study aimed to compare the effects of mulching with inorganic (round gravel, RG), organic (wood chips, WC), and living (manila turf grass, MG) materials on soil properties at 0–5-cm and 5–10-cm depths, as well as on the growth and physiological features of Osmanthus fragrans L. ‘Rixianggui’ plants. Soil samples were collected at three different time points from field plots of O. fragrans plants treated with the different mulching treatments. Moisture at both soil depths was significantly higher after mulching with RG and WC than that in the unmulched control (CK) treatment. Mulching did not affect soil bulk density, pH, or total nitrogen content, but consistently improved soil organic matter. The available nitrogen in the soil increased after RG and WC treatments, but decreased after MG treatment during the experimental period. Mulching improved plant growth by increasing root activity, soluble sugar, and chlorophyll a content, as well as by providing suitable moisture conditions and nutrients in the root zone. Plant height and trunk diameter were remarkably increased after mulching, especially with RG and WC. However, while MG improved plant growth at the beginning of the treatment, the ‘Rixianggui’ plants later showed no improvement in growth. This was probably because MG competed with the plants for water and available nitrogen in the soil. Thus, our findings suggest that RG and WC, but not MG, improved the soil environment and the growth of ‘Rixianggui’ plants. Considering the effect of mulching on soil properties and plant growth and physiology, round gravel and wood chips appear to be a better choice than manila turf grass in ‘Rixianggui’ nurseries. Further studies are required to determine the effects of mulch quality and mulch-layer thickness on shoot and root growths. PMID:27508410

  2. Small Scale Spatial Variability of Soil Properties and Nutrients in a Ferralsol under Corn

    NASA Astrophysics Data System (ADS)

    Alves, M. C.; Vidal Vázquez, E.; Pereira de Almeida, V.; Paz-Ferreiro, J.

    2012-04-01

    Spatial variability of soil attributes, both in natural and agricultural landscapes can be rather large. This heterogeneity results from interactions between pedogenetic processes and soil formation factors. In cultivated soils much variability can also occur as a result of land use and management effect, i.e. agricultural systems and practices. Therefore, the main objectives of this work were to investigate the statistical and geostatistical variability of selected properties in a soil cultivated with corn. The experimental work was carried out in Ilha Solteira, São Paulostate, Brazil and the soil was classified as an Oxisol (SSA), i.e. "Latossolo Vermelho" according to the Brazilian Soil Classification System. Eighty-four soil samples were collected at each of two different depths (0-10 and 10-20 cm) from the one-hectare plot studied. Sampling included a combination of grid and nesting schemes in order to allow description of the spatial variability at different scales. Soil texture fractions (sand, silt clay), organic matter content and pH (CaCl2) were determined using standard methods. Moreover, exchangeable bases (Ca, Mg, K), cation exchange capacity (CEC) and P were determined after exchange resin extraction. In the two depths studied, extractable P, K and Mg contents were found to be highly variable (C.V. > 30%), organic matter content and CEC showed a medium variability (C.V. ≈ 15-30%) and base percent saturation and pH exhibited a low variation (< 15%). Experimental semivariograms were computed and modeled and used to map the spatial variability of the study properties. Semivariograms provided a description of the pattern of spatial variability and some insight into possible process affecting the spatial distribution of the assessed soil properties. Sensitivity of nutrient spatial requirements to between field variability was discussed on the basis of the results obtained. In addition, the usefulness of kriging maps to improve and optimize productivity

  3. Effects of Mulching on Soil Properties and Growth of Tea Olive (Osmanthus fragrans).

    PubMed

    Ni, Xue; Song, Weiting; Zhang, Huanchao; Yang, Xiulian; Wang, Lianggui

    2016-01-01

    Different mulches have variable effects on soil physical properties and plant growth. This study aimed to compare the effects of mulching with inorganic (round gravel, RG), organic (wood chips, WC), and living (manila turf grass, MG) materials on soil properties at 0-5-cm and 5-10-cm depths, as well as on the growth and physiological features of Osmanthus fragrans L. 'Rixianggui' plants. Soil samples were collected at three different time points from field plots of O. fragrans plants treated with the different mulching treatments. Moisture at both soil depths was significantly higher after mulching with RG and WC than that in the unmulched control (CK) treatment. Mulching did not affect soil bulk density, pH, or total nitrogen content, but consistently improved soil organic matter. The available nitrogen in the soil increased after RG and WC treatments, but decreased after MG treatment during the experimental period. Mulching improved plant growth by increasing root activity, soluble sugar, and chlorophyll a content, as well as by providing suitable moisture conditions and nutrients in the root zone. Plant height and trunk diameter were remarkably increased after mulching, especially with RG and WC. However, while MG improved plant growth at the beginning of the treatment, the 'Rixianggui' plants later showed no improvement in growth. This was probably because MG competed with the plants for water and available nitrogen in the soil. Thus, our findings suggest that RG and WC, but not MG, improved the soil environment and the growth of 'Rixianggui' plants. Considering the effect of mulching on soil properties and plant growth and physiology, round gravel and wood chips appear to be a better choice than manila turf grass in 'Rixianggui' nurseries. Further studies are required to determine the effects of mulch quality and mulch-layer thickness on shoot and root growths. PMID:27508410

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

    PubMed

    Bolster, Carl H; Abit, Sergio M

    2012-01-01

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

  5. Effects of long-term irrigation with treated wastewater on the hydraulic properties of a clayey soil

    NASA Astrophysics Data System (ADS)

    Assouline, S.; Narkis, K.

    2011-08-01

    The increasing demand for freshwater (FW) for domestic use turns treated wastewater (WW) into an attractive source of water for irrigated agriculture. The main goal of this study was to evaluate the impact of 15 yrs of irrigation with WW on hydraulic properties and flow processes in a clayey soil, compared to FW use. It also quantitatively addressed the distribution with depth along the soil profile of that impact on soil hydraulic properties. Standard methods used in soil physics at the laboratory scale, and numerical solutions of the flow equations on the basis of HYDRUS, were applied to define fundamental soil hydraulic properties of disturbed soil samples from 0-20, 20-40, and 40-60 cm layers in the root zone. Results showed that saturated hydraulic conductivity, sorptivity, and infiltration rates are consistently lower in the WW irrigated soil samples at all depths. Water retention and hydraulic conductivity functions were affected by the use of WW, leading to a smaller, simulated-wetted volume below a dripper for the WW-irrigated soil case. These results illustrate the combined and complex effect of WW use on soil-exchangeable sodium percentage, and suggest changes in contact angle and pore size distribution. They also suggest that WW application will affect differently different zones in the soil profile, depending on irrigation management parameters and plant uptake characteristics.

  6. Some surface properties of Apollo 17 soils

    NASA Technical Reports Server (NTRS)

    Holmes, H. F.; Fuller, E. L., Jr.; Gammage, R. B.

    1974-01-01

    The surface chemistry of Apollo 17 lunar fines samples 74220 (the orange soil) and 74241 (the gray control soil) has been studied by measuring the adsorption of nitrogen, argon, and oxygen (all at -196 C) and also water vapor (at 20 C or 22 C). In agreement with results for samples from other missions, both samples had low initial specific surface areas, consisted of nonporous particles, and were attacked by water vapor at high relative pressures to give an increased specific surface area and create a pore system which gave rise to a capillary condensation hysteresis loop in the adsorption isotherms. In contrast to previous samples, both of the Apollo 17 soils were partially hydrophobic in their initial interaction with water vapor (both samples were completely hydrophilic after the reaction with water). The results are consistent with formation at high temperatures without subsequent exposure to significant amounts of water.

  7. Biochemical resistance of pyrogenic organic matter in fire-affected mineral soils of Southern Europe

    NASA Astrophysics Data System (ADS)

    Knicker, H.; González Vila, F. J.; Clemente Salas, L.

    2012-04-01

    Incorporated into the soil, naturally formed pyrogenic organic matter (PyOM) is considered as highly recalcitrant, but direct estimation of PyOM decomposition rates are scarce. With this aim in mind, we subjected organic matter (OM) of fire-affected and unaffected soils to biochemical degradation under laboratory conditions and monitored CO2 production over a period of seven months. The soils derived from fire affected and unaffected areas of the Sierra de Aznalcóllar and the Doñana National Park, Southern Spain. Virtual fractionation of the solid-state 13C nuclear magnetic resonance (NMR) spectra of the fire affected soils into fire-unaffected soil organic matter (SOM) and PyOM yielded charcoal C contributions of 30 to 50% to the total organic C (Corg) of the sample derived from the Aznalcóllar region. Fitting the respiration data with a double exponential decay model revealed a fast carbon flush during the first three weeks of the experiment. Solid-state 13C NMR spectroscopy evidenced the contribution of aromatic moieties of the PyOM to this initial carbon release and to the biosynthesis of new microbial biomass. The input of PyOM resulted in an increase of the mean residence time (MRT) of the slow OM pool of the soil by a factor of 3 to 4 to approximately 40 years which rises doubts rises doubts about the presumed big influence of PyOM as an additional C-sink in soils. On the other hand, although being small the difference in turnover rates is evident and has some major implication with respect to long-term alteration of the chemical composition of OM in fire-affected soils. Based on the obtained results and the analysis of PyOM in other soil systems, a conceptual model is presented which can explain the different behavior of PyOM under different soil conditions.

  8. Pore size distribution of soil near saturation as affected by soil type, land use, and soil amendments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Storage and flow of water in soil voids, which are related to the size and geometry of the voids and flow rate are usually controlled by the void of the smallest size. Another reason for the complexity of water flow in soils is the intricate nature and change of the soil pores due to the modificatio...

  9. Environmental Factors Affect Acidobacterial Communities below the Subgroup Level in Grassland and Forest Soils

    PubMed Central

    Naether, Astrid; Foesel, Bärbel U.; Naegele, Verena; Wüst, Pia K.; Weinert, Jan; Bonkowski, Michael; Alt, Fabian; Oelmann, Yvonne; Polle, Andrea; Lohaus, Gertrud; Gockel, Sonja; Hemp, Andreas; Kalko, Elisabeth K. V.; Linsenmair, Karl Eduard; Pfeiffer, Simone; Renner, Swen; Schöning, Ingo; Weisser, Wolfgang W.; Wells, Konstans; Fischer, Markus; Overmann, Jörg

    2012-01-01

    In soil, Acidobacteria constitute on average 20% of all bacteria, are highly diverse, and are physiologically active in situ. However, their individual functions and interactions with higher taxa in soil are still unknown. Here, potential effects of land use, soil properties, plant diversity, and soil nanofauna on acidobacterial community composition were studied by cultivation-independent methods in grassland and forest soils from three different regions in Germany. The analysis of 16S rRNA gene clone libraries representing all studied soils revealed that grassland soils were dominated by subgroup Gp6 and forest soils by subgroup Gp1 Acidobacteria. The analysis of a large number of sites (n = 57) by 16S rRNA gene fingerprinting methods (terminal restriction fragment length polymorphism [T-RFLP] and denaturing gradient gel electrophoresis [DGGE]) showed that Acidobacteria diversities differed between grassland and forest soils but also among the three different regions. Edaphic properties, such as pH, organic carbon, total nitrogen, C/N ratio, phosphorus, nitrate, ammonium, soil moisture, soil temperature, and soil respiration, had an impact on community composition as assessed by fingerprinting. However, interrelations with environmental parameters among subgroup terminal restriction fragments (T-RFs) differed significantly, e.g., different Gp1 T-RFs correlated positively or negatively with nitrogen content. Novel significant correlations of Acidobacteria subpopulations (i.e., individual populations within subgroups) with soil nanofauna and vascular plant diversity were revealed only by analysis of clone sequences. Thus, for detecting novel interrelations of environmental parameters with Acidobacteria, individual populations within subgroups have to be considered. PMID:22885760

  10. From the study of fire effects on individual soil properties to the development of soil quality indices. 1. The pioneer research

    NASA Astrophysics Data System (ADS)

    Mataix-Solera, Jorge; Zornoza, Raúl

    2013-04-01

    Although forest fires must be considered as a natural factor in Mediterranean ecosystems, the modification of its natural regime during last five decades has thansformed them in an environmental problem. In the Valencia region (E Spain) 1994 was the worst year in the history affecting more than 120,000 hectares. I started my Ph.D that year by studying the effects of fires in soil properties. The availability to be able to analyse a great set of different types of soil properties in the laboratories of University of Alicante allowed me to explore how fires could affect physical, chemical and micobiological soil properties. After years studying different soil properties, finding that several factors are involved, including: fire intensity and severity, vegetation, soil type, climate conditions, etc. (Mataix-Solera and Doerr, 2004; Mataix-Solera et al., 2008, 2011) my research as Ph-D supervisor has been focussed to investigate more in depth some selected properties, such as aggregate stability and water repellency (Arcenegui et al., 2007, 2008). But one of the main problems in the studies conducted with samples affected by wildfires is that for the evaluation of the fire impact in the soil it is necessary to have control (unburned) soil samples from a similar non-affected near area. The existing spatial variability under field conditions does not allow having comparable samples in some acses to develop a correct assessment. With this idea in mind one of my Ph.D researcher (R. Zornoza) dedicated his thesis to develope soil quality indices capable to assess the impact of soil perturbations without comparing groups of samples, but evaluating the equilibrium among different soil properties within each soil sample (Zornoza et al., 2007, 2008). Key words: wildfire, Mediterranean soils, soil degradation, wàter repellency, aggregate stability References: Arcenegui, V., Mataix-Solera, J., Guerrero, C., Zornoza, R., Mayoral, A.M., Morales, J., 2007. Factors controlling the

  11. Anthropogenic lead distribution in rodent-affected and undisturbed soils in southern California

    SciTech Connect

    Mace, J.E.; Graham, R.C.; Amrhein, C.

    1997-01-01

    Anthropogenic Pb is the world`s largest and most widespread heavy metal contamination. Inspired by recent evidence suggesting a faster redistribution of Pb through the mineral soil profile than was previously expected, we investigated the effects of rodent activity on Pb redistribution. Total Pb was analyzed at the 0-1, 1-4, and 4-7-cm depths in a rodent-affected soil and in an undisturbed soil, in the same proximity and with the same parent material, in the Box Springs Mountains near Riverside, California. Six replicate sites of each condition were sampled. Lead was recovered by a digest in 4 M HNO{sub 3} and measured using a graphite furnace atomic absorption spectrophotometer. Anthropotenic Pb content to a 7-cm depth averaged 19 mg kg{sup -1} in undisturbed soils and 10 mg kg{sup -1} in rodent-affected soils. In both soils, the highest concentrations of Pb were located in the top 4 cm of the profile. After accounting for an estimated native Pb ({approximately}3.3 mg kg{sup -1}), we determined that 20 to 38 kg ha{sup -1} Pb has been deposited on these soils, through air pollution. Our findings suggest rodents significantly modify the distribution of anthropogenic Pb in the rodent-affected soils of the box Springs Mountains primarily in two ways: (i) by reducing Pb concentration in surface soils, thereby decreasing the potential for erosional redistribution of Pb, and (ii) by decreasing Pb transport time through the soil profile as a result of physical mixing. This redistribution mechanism is likely applicable to other surface deposited anthropogenic contaminants that have similarly low soil mobility. 18 refs., 1 fig., 2 tabs.

  12. Linking soil and sediment properties for research on biogeochemical cycles

    NASA Astrophysics Data System (ADS)

    Kuhn, Nikolaus J.

    2013-04-01

    Conventional perspectives on soil erosion include the on-site damage to soil and reductions in crop yield, as well as the resulting off-site effects on water quality, runoff and sediment loads in rivers. Our evolving understanding of the Earth System has added a new dimension to the role of soil erosion within the global geochemical cycles. First, the relevance of soil as a nutrient and Carbon (C) pool was recognized. Initially, the role of soils in the global C cycle was largely considered to be limited to a vertical exchange of greenhouse house gases (GHG) between vegetation, soil and atmosphere and thus mostly studied by soil scientists, plant ecologists and climatologists. Even Critical Zone research focused mostly on weathering and regolith properties and ignored lateral fluxes of dissolved or particulate organic matter. Since the late 1990s, a wider role of soils in biogeochemical cycles has emerged. Recent estimates place the lateral movement of C between soil and sediment pools in terrestrial ecosystems (including rivers and lakes) at approximately 0.6 to 1.5 Gt per year. Some of the eroded C is replaced by photosynthesis from the atmosphere, but at a cost of additional emissions, for example due to fertilizer production. The long-term fate of the eroded and deposited soil organic matter is subject to an open debate and suffers from a lack of reliable spatial information on lateral C fluxes and its subsequent fate in terrestrial ecosystems. The connection between soil C pool, GHG emissions and erosion illustrates the relevance of surface processes for the C fluxes between Earth's spheres. Accordingly, soil is now considered as mobile system to make accurate predictions about the consequences of global change for terrestrial biogeochemical cycles and climate feedbacks. This expanded perspective on soils as dynamic pool of weathering regolith, sediment, nutrients and C at the interface between the geospheres requires the analysis of relevant soil properties

  13. Linking Soil and Sediment Properties for research on Biogeochemical Cycles

    NASA Astrophysics Data System (ADS)

    Kuhn, N. J.

    2012-04-01

    Conventional perspectives on soil erosion include the on-site damage to soil and reductions in crop yield, as well as the resulting off-site effects on water quality, runoff and sediment loads in rivers. Our evolving understanding of the Earth System has added a new dimension to the role of soil erosion within the global geochemical cycles. First, the relevance of soil as a nutrient and Carbon (C) pool was recognized. Initially, the role of soils in the global C cycle was largely considered to be limited to a vertical exchange of greenhouse house gases (GHG) between vegetation, soil and atmosphere and thus mostly studied by soil scientists, plant ecologists and climatologists. Even Critical Zone research focused mostly on weathering and regolith properties and ignored lateral fluxes of dissolved or particulate organic matter. Since the late 1990s, a wider role of soils in biogeochemical cycles has emerged. Recent estimates place the lateral movement of C between soil and sediment pools in terrestrial ecosystems (including rivers and lakes) at approximately 0.6 to 1.5 Gt per year. Some of the eroded C is replaced by photosynthesis from the atmosphere, but at a cost of additional emissions, for example due to fertilizer production. The long-term fate of the eroded and deposited soil organic matter is subject to an open debate and suffers from a lack of reliable spatial information on lateral C fluxes and its subsequent fate in terrestrial ecosystems. The connection between soil C pool, GHG emissions and erosion illustrates the relevance of surface processes for the C fluxes between Earth's spheres. Accordingly, soil is now considered as mobile system to make accurate predictions about the consequences of global change for terrestrial biogeochemical cycles and climate feedbacks. This expanded perspective on soils as dynamic pool of weathering regolith, sediment, nutrients and C at the interface between the geospheres requires the analysis of relevant soil properties

  14. Effects of rock fragments on water dynamics in a fire-affected soil

    NASA Astrophysics Data System (ADS)

    Gordillo-Rivero, Ángel J.; García-Moreno, Jorge; Jordán, Antonio; Zavala, Lorena M.

    2014-05-01

    Rock fragments (RF) are common in the surface of Mediterranean semiarid soils, and have important effects on the soil physical (bulk density and porosity) and hydrological processes (infiltration, evaporation, splash erosion and runoff generation) (Poesen and Lavee, 1994; Rieke-Zapp et al., 2007). In some cases, RFs in Mediterranean areas have been shown to protect bare soils from erosion risk (Cerdà, 2001; Martínez-Zavala, Jordán, 2008; Zavala et al., 2010). Some of these effects are much more relevant when vegetation cover is low or has been reduced after land use change or other causes, as forest fires. Although very few studies exist, the interest on the hydrological effects of RFs in burned areas is increasing recently. After a forest fire, RFs may contribute significantly to soil recovery. In this research we have studied the effect of surface and embedded RFs on soil water control, infiltration and evaporation in calcareous fire-affected soils from a Mediterranean area (SW Spain). For this study, we selected an area with soils derived from limestone under holm oak forest, recently affected by a moderate severity forest fire. The proportion of RF cover showed a significant positive relation with soil water-holding capacity and infiltration rates, although infiltration rate reduced significantly when RF cover increased above a certain threshold. Soil evaporation rate decreased with increasing volumetric content of RFs and became stable with RF contents approximately above 30%. Evaporation also decreased with increasing RF cover. When RF cover increased above 50%, no significant differences were observed between burned and control vegetated plots. REFERENCES Poesen, J., Lavee, H. 1994. Rock fragments in top soils: significance and processes. Catena Supplement 23, 1-28. Cerdà, A. 2001. Effect of rock fragment cover on soil infiltration, interrill runoff and erosion. European Journal of Soil Science 52, 59-68. DOI: 10.1046/j.1365-2389.2001.00354.x. Rieke

  15. Key biogeochemical factors affecting soil carbon storage in Posidonia meadows

    NASA Astrophysics Data System (ADS)

    Serrano, Oscar; Ricart, Aurora M.; Lavery, Paul S.; Mateo, Miguel Angel; Arias-Ortiz, Ariane; Masque, Pere; Rozaimi, Mohammad; Steven, Andy; Duarte, Carlos M.

    2016-08-01

    Biotic and abiotic factors influence the accumulation of organic carbon (Corg) in seagrass ecosystems. We surveyed Posidonia sinuosa meadows growing in different water depths to assess the variability in the sources, stocks and accumulation rates of Corg. We show that over the last 500 years, P. sinuosa meadows closer to the upper limit of distribution (at 2-4 m depth) accumulated 3- to 4-fold higher Corg stocks (averaging 6.3 kg Corg m-2) at 3- to 4-fold higher rates (12.8 g Corg m-2 yr-1) compared to meadows closer to the deep limits of distribution (at 6-8 m depth; 1.8 kg Corg m-2 and 3.6 g Corg m-2 yr-1). In shallower meadows, Corg stocks were mostly derived from seagrass detritus (88 % in average) compared to meadows closer to the deep limit of distribution (45 % on average). In addition, soil accumulation rates and fine-grained sediment content (< 0.125 mm) in shallower meadows (2.0 mm yr-1 and 9 %, respectively) were approximately 2-fold higher than in deeper meadows (1.2 mm yr-1 and 5 %, respectively). The Corg stocks and accumulation rates accumulated over the last 500 years in bare sediments (0.6 kg Corg m-2 and 1.2 g Corg m-2 yr-1) were 3- to 11-fold lower than in P. sinuosa meadows, while fine-grained sediment content (1 %) and seagrass detritus contribution to the Corg pool (20 %) were 8- and 3-fold lower than in Posidonia meadows, respectively. The patterns found support the hypothesis that Corg storage in seagrass soils is influenced by interactions of biological (e.g., meadow productivity, cover and density), chemical (e.g., recalcitrance of Corg stocks) and physical (e.g., hydrodynamic energy and soil accumulation rates) factors within the meadow. We conclude that there is a need to improve global estimates of seagrass carbon storage accounting for biogeochemical factors driving variability within habitats.

  16. Arid soil microbial enzymatic activity profile as affected by geographical location and soil degradation status

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evaluating soil health is critical for any successful remediation effort. Arid lands, with their minimal carbon and water contents, low nutritional status and restricted, seasonal microbial activity pose specific challenges to soil health restoration and by extension, restoration of ecosystem repr...

  17. SOIL PHYSICOCHEMICAL PARAMETERS AFFECTING METAL AVAILABILITY IN SLUDGE-AMENDED SOILS

    EPA Science Inventory

    A series of laboratory studies was conducted to determine the effects of soil pH and redox potential onlevels of trace metals (Cu, Zn, Cd, Pb, Cr, Ni, and As) in selected chemical forms and their availability to plants. This research demonstrates the important effects of soil red...

  18. How can climate, soil, and monitoring schedule affect temporal stability of soil water contents

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Temporal stability (TS) of soil water content (SWC) reflects the spatio-temporal organization of soil water. The TS SWC was originally recognized as a phenomenon that can be used to provide temporal average SWC of an area of interest from observations at a representative location(s). Currently appli...

  19. SURVIVAL OF SALMONELLA TYPHIMURIUM IN FOUR SOIL MICROCOSMS AS AFFECTED BY SOIL TYPE AND INCUBATION TEMPERATURE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Survival of Salmonella typhimurium was determined in sterile and non-sterile microcosms in four soil series (Brooksville, Leeper, Marietta, and Ruston) held at 10, 15, 25 and 35 degrees C. Exponential linear destruction was observed for S. typhimurium in non-sterile soil stored at all temperatures....

  20. Unraveling the size distributions of surface properties for purple soil and yellow soil.

    PubMed

    Tang, Ying; Li, Hang; Liu, Xinmin; Zhu, Hualing; Tian, Rui

    2015-06-01

    Soils contain diverse colloidal particles whose properties are pertinent to ecological and human health, whereas few investigations systematically analyze the surface properties of these particles. The objective of this study was to elucidate the surface properties of particles within targeted size ranges (i.e. >10, 1-10, 0.5-1, 0.2-0.5 and <0.2 μm) for a purple soil (Entisol) and a yellow soil (Ultisol) using the combined determination method. The mineralogy of corresponding particle-size fractions was determined by X-ray diffraction. We found that up to 80% of the specific surface area and 85% of the surface charge of the entire soil came from colloidal-sized particles (<1 μm), and almost half of the specific surface area and surface charge came from the smallest particles (<0.2 μm). Vermiculite, illite, montmorillonite and mica dominated in the colloidal-sized particles, of which the smallest particles had the highest proportion of vermiculite and montmorillonite. For a given size fraction, the purple soil had a larger specific surface area, stronger electrostatic field, and higher surface charge than the yellow soil due to differences in mineralogy. Likewise, the differences in surface properties among the various particle-size fractions can also be ascribed to mineralogy. Our results indicated that soil surface properties were essentially determined by the colloidal-sized particles, and the <0.2 μm nanoparticles made the largest contribution to soil properties. The composition of clay minerals within the diverse particle-size fractions could fully explain the size distributions of surface properties. PMID:26040734

  1. Wind erosion as affected by soil temporal variation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The wind erosion prediction system (WEPS) requires information about numerous spatial and temporal variables and complex interactions that affect erosion, particulate matter (PM 10 and 2.5) generation, and nutrient loss. Abrasion of clods and crusts, aggregate slaking, and dispersion during wind and...

  2. Multivariate 3D modelling of Scottish soil properties

    NASA Astrophysics Data System (ADS)

    Poggio, Laura; Gimona, Alessandro

    2015-04-01

    Information regarding soil properties across landscapes at national or continental scales is critical for better soil and environmental management and for climate regulation and adaptation policy. The prediction of soil properties variation in space and time and their uncertainty is an important part of environmental modelling. Soil properties, and in particular the 3 fractions of soil texture, exhibit strong co-variation among themselves and therefore taking into account this correlation leads to spatially more accurate results. In this study the continuous vertical and lateral distributions of relevant soil properties in Scottish soils were modelled with a multivariate 3D-GAM+GS approach. The approach used involves 1) modelling the multivariate trend with full 3D spatial correlation, i.e., exploiting the values of the neighbouring pixels in 3D-space, and 2) 3D kriging to interpolate the residuals. The values at each cell for each of the considered depth layers were defined using a hybrid GAM-geostatistical 3D model, combining the fitting of a GAM (generalised Additive Models) to estimate multivariate trend of the variables, using a 3D smoother with related covariates. Gaussian simulations of the model residuals were used as spatial component to account for local details. A dataset of about 26,000 horizons (7,800 profiles) was used for this study. A validation set was randomly selected as 25% of the full dataset. Numerous covariates derived from globally available data, such as MODIS and SRTM, are considered. The results of the 3D-GAM+kriging showed low RMSE values, good R squared and an accurate reproduction of the spatial structure of the data for a range of soil properties. The results have an out-of-sample RMSE between 10 to 15% of the observed range when taking into account the whole profile. The approach followed allows the assessment of the uncertainty of both the trend and the residuals.

  3. Thermal properties of soils: effect of biochar application

    NASA Astrophysics Data System (ADS)

    Usowicz, Boguslaw; Lukowski, Mateusz; Lipiec, Jerzy

    2014-05-01

    Thermal properties (thermal conductivity, heat capacity and thermal diffusivity) have a significant effect on the soil surface energy partitioning and resulting in the temperature distribution. Thermal properties of soil depend on water content, bulk density and organic matter content. An important source of organic matter is biochar. Biochar as a material is defined as: "charcoal for application as a soil conditioner". Biochar is generally associated with co-produced end products of pyrolysis. Many different materials are used as biomass feedstock for biochar, including wood, crop residues and manures. Additional predictions were done for terra preta soil (also known as "Amazonian dark earth"), high in charcoal content, due to adding a mixture of charcoal, bone, and manure for thousands of years i.e. approximately 10-1,000 times longer than residence times of most soil organic matter. The effect of biochar obtained from the wood biomass and other organic amendments (peat, compost) on soil thermal properties is presented in this paper. The results were compared with wetland soils of different organic matter content. The measurements of the thermal properties at various water contents were performed after incubation, under laboratory conditions using KD2Pro, Decagon Devices. The measured data were compared with predictions made using Usowicz statistical-physical model (Usowicz et al., 2006) for biochar, mineral soil and soil with addition of biochar at various water contents and bulk densities. The model operates statistically by probability of occurrence of contacts between particular fractional compounds. It combines physical properties, specific to particular compounds, into one apparent conductance specific to the mixture. The results revealed that addition of the biochar and other organic amendments into the soil caused considerable reduction of the thermal conductivity and diffusivity. The mineral soil showed the highest thermal conductivity and diffusivity

  4. Low temperature thermophysical properties of lunar soil

    NASA Technical Reports Server (NTRS)

    Cremers, C. J.

    1973-01-01

    The thermal conductivity and thermal diffusivity of lunar fines samples from the Apollo 11 and Apollo 12 missions, determined at low temperatures as a function of temperature and various densities, are reviewed. It is shown that the thermal conductivity of lunar soil is nearly the same as that of terrestrial basaltic rock under the same temperature and pressure conditions.

  5. Geochemical and physical properties of wetland soils at the Savannah River site

    SciTech Connect

    Dixon, K.L; Rogers, V.A.; Conner, S.P.; Cummings, C.L.; Gladden, J.B.; Weber, J.M.

    1996-05-01

    The Savannah River Site (SRS), located in Aiken, Allendale, and Barnwell Counties, South Carolina, is a nuclear production facility operated for the U.S. Department of Energy (DOE) by Westinghouse Savannah River Company (WSRC). To facilitate future human health and ecological risk assessments, treatability studies, remedial investigations, and feasibility studies for its wetland areas, SRS needs a database of background geochemical and physical properties of wetland soils. These data are needed for comparison to data collected from wetland soils that may have been affected by SRS operations. SRS contains 36,000 acres of wetlands and an additional 5,000 acres of bottom land soils subject to flooding. Recent studies of wetland soils near various waste units at SRS show that some wetlands have been impacted by releases of contaminants resulting from SRS operations (WSRC, 1992). Waste waters originating from the operations facilities typically have been discharged into seepage basins located in upland soils, direct discharge of waste water to wetland areas has been minimal. This suggests that impacted wetland areas have been affected indirectly as a result of transport mechanisms such as surface runoff, groundwater seeps, fluvial or sediment transport, and leaching. Looney et al. (1990) conducted a study to characterize the geochemical and physical properties of upland soils and shallow sediments on the SRS. A primary objective of the upland study was to collect the data needed to assess the qualitative and quantitative impacts of SRS operations on the environment. By comparing the upland soils data to data collected from waste units located in similar soils, SRS impacts could be assessed. The data were also intended to aid in selection of remediation alternatives. Because waste units at SRS have historically been located in upland areas, wetland soils were not sampled. (Abstract Truncated)

  6. Constitutive Soil Properties for Unwashed Sand and Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    Thomas, Michael A.; Chitty, Daniel E.; Gildea, Martin L.; T'Kindt, Casey M.

    2008-01-01

    Accurate soil models are required for numerical simulations of land landings for the Orion Crew Exploration Vehicle. This report provides constitutive material models for one soil, unwashed sand, from NASA Langley's gantry drop test facility and three soils from Kennedy Space Center (KSC). The four soil models are based on mechanical and compressive behavior observed during geotechnical laboratory testing of remolded soil samples. The test specimens were reconstituted to measured in situ density and moisture content. Tests included: triaxial compression, hydrostatic compression, and uniaxial strain. A fit to the triaxial test results defines the strength envelope. Hydrostatic and uniaxial tests define the compressibility. The constitutive properties are presented in the format of LS-DYNA Material Model 5: Soil and Foam. However, the laboratory test data provided can be used to construct other material models. The four soil models are intended to be specific to the soil conditions discussed in the report. The unwashed sand model represents clayey sand at high density. The KSC models represent three distinct coastal sand conditions: low density dry sand, high density in-situ moisture sand, and high density flooded sand. It is possible to approximate other sands with these models, but the results would be unverified without geotechnical tests to confirm similar soil behavior.

  7. Soil moisture affects fatty acids and oil quality parameters in peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Drought affects yield of peanut, but its effect on oleic and linoleic acids that influence its oil quality of peanut genotypes with different levels of drought resistance has not been clearly investigated. Therefore, the aims of this research were to determine whether soil water levels could affect...

  8. Soil pH, soil type and replant disease affect growth and nutrient absorption in apple rootstocks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rootstocks are the foundation of a healthy and productive orchard. They are the interface between the scion and the soil, providing anchorage, water, nutrients, and disease protection that ultimately affect the productivity and sustainability of the orchard. Recent advances in the science of genet...

  9. Pyrogenic Carbon in forest soils across climate and soil property gradients in Switzerland

    NASA Astrophysics Data System (ADS)

    Reisser, Moritz; González Domínguez, Beatriz R.; Hagedorn, Frank; Abiven, Samuel

    2016-04-01

    Soil organic carbon (SOC) is an important measure for soil quality. Usually a high organic matter content in soils is favourable for most ecosystems. As a very stable component, pyrogenic organic carbon (PyC) can be of major interest to investigate to potential of organic matter, to persist very long in soils. Recent studies have shown, that the mean residence time of organic matter is not only due to its intrinsic chemical nature, but also to a variety of abiotic and biotic variables set by the ecosystem. Especially for PyC it is unclear, whether its content is related to fire regime, soil properties or other climatic conditions. In this study we wanted to investigate, how climatic and soil-related conditions are influencing the persistence of PyC in soils. Therefore we used a sample set from Swiss forest soil (n = 54), which was designed for the purpose of having most differing climatic conditions (aridity and temperature) and a large range of soil properties (pH between 3.4 and 7.6; clay content between 4.7 % and 60 %). The soils were sampled in the first 20 cm of the mineral horizon on a representative plot area of 40 x 40 m. The soils were sieved to 2 mm and dried prior to the analysis. We used the benzene polycarboxylic acids (BPCA) molecular marker method to quantify and characterize PyC in these soil samples. Despite the large span in environmental conditions, we observed rather small differences in the contribution of PyC to SOC between warmer and colder, as well as between wetter and dryer soils. The PyC content in SOC lies well in range with a global average for forest soils estimated in other studies. Stocks of PyC vary more than the content, because of the large range of SOC contents in the samples. The influence of other parameters like soil properties is still under investigation. Qualitative investigation of the BPCAs showed that the degree of condensation, defined by the relative amount of B6CA in the total BPCA, was higher in warmer soils. This

  10. Fallow Effects on Improving Soil Properties and Decreasing Erosion: Atlantic Forest, Southeastern Brazil

    NASA Astrophysics Data System (ADS)

    Miranda, J. P.; Silva, L. M.; Lima, R. L.; Donagemma, G. K.; Bertolino, A. V. A.; Fernandes, N. F.; Correa, F. M.; Polidoro, J. C.; Tato, G.

    2009-04-01

    fallow) and forest. For each case, 12 soil samples were collected at 4 depths: 0-5, 5-10, 10-20 and 20-30cm, with 3 repetitions, leading to a total of 60 soil samples, where the following properties were characterized: porosity (micro, macro and total), bulk density and aggregate stability. Besides, in situ measurements of saturated hydraulic conductivity were conducted with a Guelph permeameter. The results obtained in this study attested that all the soil properties analyzed were affected by soil usage, especially at shallow depths, in particular macroporosity and total porosity, which have major influences on infiltration rates, runoff and soil erosion. Besides, the results suggested that the 5-year fallow (F5) was able to recover from 72% to 100% of total porosity for the 0-10cm depth layer (considering forest values as reference), while in the 2-year fallow (F2) this recovery was lower, ranging from 66 to 80%. A similar trend was observed for macroporosity, showing recovering values from 60% to 90% and from 50% to 76%, for F5 and F2, respectively. However, aggregate stability values did not show significant variations between the two fallows. Saturated hydraulic conductivity, on the other hand, presented the lowest recovering values for all the studied properties: between 13% and 58% for F5 and between 6% and 33% for F2. Comparing to the natural forest (reference value), the coffee plantations presented the worst soil conditions in terms of soil hydrology and erosion. The results presented here attested important improvements in soil physical and hydrological properties after a 5-year fallow, leading to decrease in surface runoff and soil erosion in the area.

  11. Improving root-zone soil properties for Trembling Aspen in a reconstructed mine-site soil

    NASA Astrophysics Data System (ADS)

    Dyck, M. F.; Sabbagh, P.; Bockstette, S.; Landhäusser, S.; Pinno, B.

    2014-12-01

    Surface mining activities have significantly depleted natural tree cover, especially trembling aspen (Populus tremuloides), in the Boreal Forest and Aspen Parkland Natural Regions of Alberta. The natural soil profile is usually destroyed during these mining activities and soil and landscape reconstruction is typically the first step in the reclamation process. However, the mine tailings and overburden materials used for these new soils often become compacted during the reconstruction process because they are subjected to high amounts of traffic with heavy equipment. Compacted soils generally have low porosity and low penetrability through increased soil strength, making it difficult for roots to elongate and explore the soil. Compaction also reduces infiltration capacity and drainage, which can cause excessive runoff and soil erosion. To improve the pore size distribution and water transmission, subsoil ripping was carried out in a test plot at Genesee Prairie Mine, Alberta. Within the site, six replicates with two treatments each, unripped (compacted) and ripped (decompacted), were established with 20-m buffers between them. The main objective of this research was to characterize the effects of subsoil ripping on soil physical properties and the longevity of those effects.as well as soil water dynamics during spring snowmelt. Results showed improved bulk density, pore size distribution and water infiltration in the soil as a result of the deep ripping, but these improvements appear to be temporary.

  12. Altered precipitation regime affects the function and composition of soil microbial communities on multiple time scales.

    PubMed

    Zeglin, L H; Bottomley, P J; Jumpponen, A; Rice, C W; Arango, M; Lindsley, A; McGowan, A; Mfombep, P; Myrold, D D

    2013-10-01

    Climate change models predict that future precipitation patterns will entail lower-frequency but larger rainfall events, increasing the duration of dry soil conditions. Resulting shifts in microbial C cycling activity could affect soil C storage. Further, microbial response to rainfall events may be constrained by the physiological or nutrient limitation stress of extended drought periods; thus seasonal or multiannual precipitation regimes may influence microbial activity following soil wet-up. We quantified rainfall-driven dynamics of microbial processes that affect soil C loss and retention, and microbial community composition, in soils from a long-term (14-year) field experiment contrasting "Ambient" and "Altered" (extended intervals between rainfalls) precipitation regimes. We collected soil before, the day following, and five days following 2.5-cm rainfall events during both moist and dry periods (June and September 2011; soil water potential = -0.01 and -0.83 MPa, respectively), and measured microbial respiration, microbial biomass, organic matter decomposition potential (extracellular enzyme activities), and microbial community composition (phospholipid fatty acids). The equivalent rainfall events caused equivalent microbial respiration responses in both treatments. In contrast, microbial biomass was higher and increased after rainfall in the Altered treatment soils only, thus microbial C use efficiency (CUE) was higher in Altered than Ambient treatments (0.70 +/- 0.03 > 0.46 +/- 0.10). CUE was also higher in dry (September) soils. C-acquiring enzyme activities (beta-glucosidase, cellobiohydrolase, and phenol oxidase) increased after rainfall in moist (June), but not dry (September) soils. Both microbial biomass C:N ratios and fungal:bacterial ratios were higher at lower soil water contents, suggesting a functional and/or population-level shift in the microbiota at low soil water contents, and microbial community composition also differed following wet

  13. Quantification of Heavy Metals in Mining Affected Soil and Their Bioaccumulation in Native Plant Species.

    PubMed

    Nawab, Javed; Khan, Sardar; Shah, Mohammad Tahir; Khan, Kifayatullah; Huang, Qing; Ali, Roshan

    2015-01-01

    Several anthropogenic and natural sources are considered as the primary sources of toxic metals in the environment. The current study investigates the level of heavy metals contamination in the flora associated with serpentine soil along the Mafic and Ultramafic rocks northern-Pakistan. Soil and wild native plant species were collected from chromites mining affected areas and analyzed for heavy metals (Cr, Ni, Fe, Mn, Co, Cu and Zn) using atomic absorption spectrometer (AAS-PEA-700). The heavy metal concentrations were significantly (p < 0.01) higher in mine affected soil as compared to reference soil, however Cr and Ni exceeded maximum allowable limit (250 and 60 mg kg(-1), respectively) set by SEPA for soil. Inter-metal correlations between soil, roots and shoots showed that the sources of contamination of heavy metals were mainly associated with chromites mining. All the plant species accumulated significantly higher concentrations of heavy metals as compared to reference plant. The open dumping of mine wastes can create serious problems (food crops and drinking water contamination with heavy metals) for local community of the study area. The native wild plant species (Nepeta cataria, Impatiens bicolor royle, Tegetis minuta) growing on mining affected sites may be used for soil reclamation contaminated with heavy metals. PMID:26079739

  14. The effects of soil vertical discretization, soil thermal properties, and soil heat convection by liquid water transfer on the water and energy cycles in a coupled land-atmosphere model

    NASA Astrophysics Data System (ADS)

    Wang, Fuxing; Dufresne, Jean-Louis; Chéruy, Frédérique; Ducharne, Agnès

    2015-04-01

    The soil heat transfer is an important component in general circulation model (GCM), and accurate representation of subsurface thermodynamics is essential for earth system modeling. The accuracy of the soil thermodynamics simulation is affected by many factors: (1) the bottom boundary layer position used in numerical scheme; (2) the soil thermal property (heat capacity and thermal conductivity) parameterization; as well as (3) the physical processes considered in the model. However, the impact of their correct representation on the quality of the simulated climate is poorly documented, and the way state-of-the art land surface model (LSM) used for climate simulations account for them is highly variable. For instance bottom boundary layer position varies from 2 m to 10 m or even more (100 m), the parameterizations of the soil thermal properties not always account for the soil texture effects, and the soil heat convection process is neglected in most soil thermodynamics models. In this work, we revisited the soil thermodynamics model included in the ORCHIDEE LSM in order (1) to determine the soil bottom layer depth which allows for simulating the annual cycle of temperature; (2) to improve the parameterization of the soil thermal properties (thermal conductivity and heat capacity) by accounting for both soil moisture and soil texture effects on the soil thermal properties; (3) to take into account the heat generated by liquid water movement in soil thermodynamics. The developpement of the parameterizations has been done in a 1-D framework where the results of the Finite Difference Method have been compared to the analytical solution. Sensitivity experiments with the LMDZ-ORCHIDEE coupled model (atmosphere-land component of IPSL-CM model) have been then designed to evaluate the impact of the soil thermal properties and soil heat convection on the water and energy cycles of the land-atmosphere. Main results are: (1) the 8 meter soil depth is proposed as a minimum

  15. Role of soil erodibility in affecting available nitrogen and phosphorus losses under simulated rainfall

    NASA Astrophysics Data System (ADS)

    Wang, Guoqiang; Wu, Binbin; Zhang, Lei; Jiang, Hong; Xu, Zongxue

    2014-06-01

    The loss of available nutrients and the effects of soil erodibility on available nutrients losses were rarely researched. Here, laboratory simulation experiments were conducted to determine the soil erodibility effects on the available nitrogen (AN) and phosphorus (AP) losses. The impacts of rainfall intensity and slope on AN and AP losses were also studied. Two contrasting agricultural soils (Burozems and Cinnamon) that occur throughout the northern erosion region of China were selected. Two rainfall intensities (60 and 120 mm h-1) and two slopes (10% and 20%) were studied. Overall, greater runoff, sediment and available nutrient losses occurred from the Cinnamon soil due to its greater soil erodibility, which was approximately 2.8 times greater than that of the Burozems soil. The influence of runoff on sediment was positively linear. The absolute slope of the regression line between runoff rate and sediment yield rate was suitable as a soil erodibility indicator. Runoff-associated AN and AP losses were mainly controlled by runoff rate, and were weakly affected by soil erodibility (p > 0.05). However, soil erodibility significantly influenced the sediment-associated AN and AP losses (p < 0.01), and a positive logarithmic correlation best described their relationships. Since the runoff-associated AN and AP losses dominated the total AN and AP losses for both soils, soil erodibility also exhibited negligible influence on the total AN and AP losses (p > 0.05). Increasing rainfall intensity and slope generally increased the runoff, sediment, and available nutrient losses for both soils, but had no significant influences on their relationships. Our results provide a better understanding of soil and nutrient loss mechanisms.

  16. Soil microbiological properties and enzymatic activities of long-term post-fire recovery in dry and semiarid Aleppo pine (Pinus halepensis M.) forest stands

    NASA Astrophysics Data System (ADS)

    Hedo, J.; Lucas-Borja, M. E.; Wic, C.; Andrés Abellán, M.; de Las Heras, J.

    2014-10-01

    Wildfires affecting forest ecosystems and post-fire silvicultural treatments may cause considerable changes in soil properties. The capacity of different microbial groups to recolonize soil after disturbances is crucial for proper soil functioning. The aim of this work was to investigate some microbial soil properties and enzyme activities in semiarid and dry Aleppo pine (Pinus halepensis M.) forest stands. Different plots affected by a wildfire event 17 years ago without or with post-fire silvicultural treatments five years after the fire event were selected. A mature Aleppo pine stand unaffected by wildfire and not thinned was used as a control. Physicochemical soil properties (soil texture, pH, carbonates, organic matter, electrical conductivity, total N and P), soil enzymes (urease, phosphatase, β-glucosidase and dehydrogenase activities), soil respiration and soil microbial biomass carbon were analysed in the selected forests areas and plots. The main finding was that long time after this fire event produces no differences in the microbiological soil properties and enzyme activities of soil after comparing burned and thinned, burned and not thinned, and mature plots. Thus, the long-term consequences and post-fire silvicultural management in the form of thinning have a significant effect on the site recovery after fire. Moreover, significant site variation was generally seen in soil enzyme activities and microbiological parameters. We conclude that total vegetation restoration normalises microbial parameters, and that wildfire and post-fire silvicultural treatments are not significant factors of soil properties after 17 years.

  17. Decreased summer drought affects plant productivity and soil carbon dynamics in Mediterranean woodland

    NASA Astrophysics Data System (ADS)

    Cotrufo, M. F.; Alberti, G.; Inglima, I.; Marjanović, H.; Lecain, D.; Zaldei, A.; Peressotti, A.; Miglietta, F.

    2011-06-01

    Precipitation patterns are expected to change in the Mediterranean region within the next decades, with projected decreases in total rainfall and increases in extreme events. We manipulated precipitation patterns in a Mediterranean woodland, dominated by Arbutus unedo L., to study the effects of changing precipitation regimes on above-ground net primary production (ANPP) and soil C dynamics, specifically plant-derived C input to soil and soil respiration (SR). Experimental plots were exposed to either a 20 % reduction of throughfall or to water addition targeted at maintaining soil water content above a minimum of 10 % v/v. Treatments were compared to control plots which received ambient precipitation. The throughfall manipulation experiment started in 2004 and we report data up to the 2009 growing season. Enhanced soil moisture during summer months highly stimulated annual stem primary production, litter fall, SR and net annual plant-derived C input to soil which on average increased by 130 %, 26 %, 50 % and 220 %, respectively, as compared to control. In contrast, the 20 % reduction in throughfall (equivalent to 10 % reduction of precipitation) did not significantly change soil moisture at the site, and therefore did not significantly affect ANPP or SR. We conclude that minor changes (around 10 % reduction) in precipitation amount are not likely to significantly affect ANPP or soil C dynamics in Mediterranean woodland. However, if summer rain increases, C cycling will significantly accelerate but soil C stocks are not likely to be changed in the short-term. More studies involving modelling of long term C dynamics are needed to predict if the estimated increases in soil C input under wet conditions is going to be sustained and if labile C is being substituted to stable C, with a negative effect on long term soil C stocks.

  18. Decreased summer drought affects plant productivity and soil carbon dynamics in a Mediterranean woodland

    NASA Astrophysics Data System (ADS)

    Cotrufo, M. F.; Alberti, G.; Inglima, I.; Marjanović, H.; Lecain, D.; Zaldei, A.; Peressotti, A.; Miglietta, F.

    2011-09-01

    Precipitation patterns are expected to change in the Mediterranean region within the next decades, with projected decreases in total rainfall and increases in extreme events. We manipulated precipitation patterns in a Mediterranean woodland, dominated by Arbutus unedo L., to study the effects of changing precipitation regimes on above-ground net primary production (ANPP) and soil C dynamics, specifically plant-derived C input to soil and soil respiration (SR). Experimental plots were exposed to either a 20 % reduction of throughfall or to water addition targeted at maintaining soil water content above a minimum of 10 % v/v. Treatments were compared to control plots which received ambient precipitation. Enhanced soil moisture during summer months highly stimulated annual stem primary production, litter fall, SR and net annual plant-derived C input to soil which on average increased by 130 %, 26 %, 58 % and 220 %, respectively, as compared to the control. In contrast, the 20 % reduction in throughfall (equivalent to 10 % reduction in precipitation) did not significantly change soil moisture at the site, and therefore did not significantly affect ANPP or SR. We conclude that minor changes (around 10 % reduction) in precipitation amount are not likely to significantly affect ANPP or soil C dynamics in Mediterranean woodlands. However, if summer rain increases, C cycling will significantly accelerate but soil C stocks are not likely to be changed in the short-term. More studies involving modelling of long-term C dynamics are needed to predict if the estimated increases in soil C input under wet conditions is going to be sustained and if labile C is being substituted to stable C, with a negative effect on long-term soil C stocks.

  19. Experimental and numerical study of infiltration into arid soils with contrasting physical and textural properties

    NASA Astrophysics Data System (ADS)

    Gerke, Kirill; Edde, Ambre; Mallants, Dirk

    2013-04-01

    Dye infiltration tests were performed in the arid environments of the Ti Tree catchment, Central Australia. This area has a mean annual precipitation of 300 mm and is further known to have infrequent intensive rainfall events linked to short-term flooding. The mechanisms of groundwater recharge in these arid environments are generally unknown. The upper 1-2 m of soil play an important role in water redistribution with preferential flow often contributing to inhomogeneous moisture storage, soil water flow and groundwater recharge. Reducing uncertainty in recharge estimation thus requires a detailed study of water flow especially near the soil surface where heterogeneity may be enhanced by biological activity and geomorphological processes. Each of three infiltration tests involved application of 100 L of a mixed dye solution applied by using a standard 60-cm diameter ring infiltrometer under constant-head ponded conditions. After complete water infiltration several vertical soil sections were prepared in a soil block of approximately 1.5-2 m3. Staining patterns were photographed to provide evidence of preferential flow while numerous disturbed and undisturbed samples were collected and analysed in the laboratory to determine soil physical and hydraulic properties including saturated hydraulic conductivity, water retention curve, initial moisture content prior to dye application and bulk densities. Staining patterns in the top 30-40 cm were relatively homogeneous with some fingering. However, presence of a textural break (fine over coarse sand) hypothesized to represent a paleo-riverbed significantly affected redistribution of water, possibly acting as a capillary barrier. Measurements of soil physical properties and soil profile digital photos were used to build a 3D heterogeneous soil hydraulic property model in HYDRUS-3D. Model results for the infiltration tests were quantitatively and qualitatively compared to staining patterns obtained during field experiments

  20. Relationships between soil physicochemical, microbiological properties, and nutrient release in buffer soils compared to field soils.

    PubMed

    Stutter, Marc I; Richards, Samia

    2012-01-01

    The retention of nutrients in narrow, vegetated riparian buffer strips (VBS) is uncertain and underlying processes are poorly understood. Evidence suggests that buffer soils are poor at retaining dissolved nutrients, especially phosphorus (P), necessitating management actions if P retention is not to be compromised. We sampled 19 buffer strips and adjacent arable field soils. Differences in nutrient retention between buffer and field soils were determined using a combined assay for release of dissolved P, N, and C forms and particulate P. We then explored these differences in relation to changes in soil bulk density (BD), moisture, organic matter by loss on ignition (OM), and altered microbial diversity using molecular fingerprinting (terminal restriction fragment length polymorphism [TRFLP]). Buffer soils had significantly greater soil OM (89% of sites), moisture content (95%), and water-soluble nutrient concentrations for dissolved organic C (80%), dissolved organic N (80%), dissolved organic P (55%), and soluble reactive P (70%). Buffer soils had consistently smaller bulk densities than field soils. Soil fine particle release was generally greater for field than buffer soils. Significantly smaller soil bulk density in buffer soils than in adjacent fields indicated increased porosity and infiltration in buffers. Bacterial, archaeal, and fungal communities showed altered diversity between the buffer and field soils, with significant relationships with soil BD, moisture, OM, and increased solubility of buffer nutrients. Current soil conditions in VBS appear to be leading to potentially enhanced nutrient leaching via increasing solubility of C, N, and P. Manipulating soil microbial conditions (by management of soil moisture, vegetation type, and cover) may provide options for increasing the buffer storage for key nutrients such as P without increasing leaching to adjacent streams. PMID:22370402

  1. Soil structure, colloids, and chemical transport as affected by short-term reducing conditions: a laboratory study

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Upland soils in the Midwestern US often undergo reducing conditions when soils are temporally flooded during the spring and remain water saturated for days or weeks. Short-term reducing conditions change the chemistry of the soil and may affect soil structure and solution chemical transport. The eff...

  2. Soil Properties, Nutrient Dynamics, and Soil Enzyme Activities Associated with Garlic Stalk Decomposition under Various Conditions

    PubMed Central

    Han, Xu; Cheng, Zhihui; Meng, Huanwen

    2012-01-01

    The garlic stalk is a byproduct of garlic production and normally abandoned or burned, both of which cause environmental pollution. It is therefore appropriate to determine the conditions of efficient decomposition, and equally appropriate to determine the impact of this decomposition on soil properties. In this study, the soil properties, enzyme activities and nutrient dynamics associated with the decomposition of garlic stalk at different temperatures, concentrations and durations were investigated. Stalk decomposition significantly increased the values of soil pH and electrical conductivity. In addition, total nitrogen and organic carbon concentration were significantly increased by decomposing stalks at 40°C, with a 5∶100 ratio and for 10 or 60 days. The highest activities of sucrase, urease and alkaline phosphatase in soil were detected when stalk decomposition was performed at the lowest temperature (10°C), highest concentration (5∶100), and shortest duration (10 or 20 days). The evidence presented here suggests that garlic stalk decomposition improves the quality of soil by altering the value of soil pH and electrical conductivity and by changing nutrient dynamics and soil enzyme activity, compared to the soil decomposition without garlic stalks. PMID:23226411

  3. Application of Multitemporal Remotely Sensed Soil Moisture for the Estimation of Soil Physical Properties

    NASA Technical Reports Server (NTRS)

    Mattikalli, N. M.; Engman, E. T.; Jackson, T. J.; Ahuja, L. R.

    1997-01-01

    This paper demonstrates the use of multitemporal soil moisture derived from microwave remote sensing to estimate soil physical properties. The passive microwave ESTAR instrument was employed during June 10-18, 1992, to obtain brightness temperature (TB) and surface soil moisture data in the Little Washita watershed, Oklahoma. Analyses of spatial and temporal variations of TB and soil moisture during the dry-down period revealed a direct relationship between changes in T and soil moisture and soil physical (viz. texture) and hydraulic (viz. saturated hydraulic conductivity, K(sat)) properties. Statistically significant regression relationships were developed for the ratio of percent sand to percent clay (RSC) and K(sat), in terms of change components of TB and surface soil moisture. Validation of results using field measured values and soil texture map indicated that both RSC and K(sat) can be estimated with reasonable accuracy. These findings have potential applications of microwave remote sensing to obtain quick estimates of the spatial distributions of K(sat), over large areas for input parameterization of hydrologic models.

  4. Preliminary study of the short term response of soil properties to forest fire in the South of Spain

    NASA Astrophysics Data System (ADS)

    Jiménez-Donaire, V.; Hueso-González, P.; Ruiz-Sinoga, J. D.

    2012-04-01

    Forest fires are a widespread phenomenon in Mediterranean environments, where they are favored by drought and high temperatures conditions that are common in summer. Wildfires affect dramatically to soil physical, chemical and biological properties, which changes the hydrological and erosive soil response. The removing of vegetation leads to erosive and degradation processes, very important immediately after the fire. The objectives of this study are: i) to compare the properties of soils affected by a recent wildfire to the properties of soils that were not; ii) to assess the effect of the vegetal cover in the short-term response of soil to wildfire. The experimental area is located in the South of Spain, 32 km western of the city of Málaga. In general, the area is characterized by a sub-humid Mediterranean climate (mean annual precipitation: 699 mm year-1; mean annual temperature: 17°C), with a substratum of alkaline metamorphic rocks. Vegetation cover consists on a mixed open wood of Quercus spp. and Pinus spp. with typical degraded Mediterranean scrub, where the dominant genus are Ulex spp. and Cistus spp. This area was partially affected by a wildfire on September 11th 2011 Three soil microenvironments were selected in burned and unburned soils: soil covered by shrubs, trees and bare soils. Unburned area was adjacent to the burned one and both of them had the same general conditions. On each microenvironment samples of the first 5 cm of soil were collected on September 19th 2011. The analyzed properties in the laboratory were pH, electrical conductivity (EC), texture, organic matter (OM), aggregate stability (AS), cationic exchange capacity and water repellency (WR). Likewise, unsaturated infiltration rate was calculated in field conditions on the sampling date. When we analyzed the samples without taking into account the vegetation cover, our results suggested that the fire affected mainly to pH (p<0.001), EC (p<0.001) and OM (p<0.01) Surprisingly, AS and

  5. Characterizing Zinc Speciation in Soils from a Smelter-Affected Boreal Forest Ecosystem.

    PubMed

    Hamilton, Jordan G; Farrell, Richard E; Chen, Ning; Feng, Renfei; Reid, Joel; Peak, Derek

    2016-03-01

    HudBay Minerals, Inc., has mined and/or processed Zn and Cu ore in Flin Flon, MB, Canada, since the 1930s. The boreal forest ecosystem and soil surrounding these facilities have been severely impacted by mixed metal contamination and HSO deposition. Zinc is one of the most prevalent smelter-derived contaminants and has been identified as a key factor that may be limiting revegetation. Metal toxicity is related to both total concentrations and speciation; therefore, X-ray absorption spectroscopy and X-ray fluorescence mapping were used to characterize Zn speciation in soils throughout the most heavily contaminated areas of the landscape. Zinc speciation was linked to two distinct soil types. Group I soils consist of exposed soils in weathered positions of bedrock outcrops with Zn present primarily as franklinite, a (ZnFeO) spinel mineral. Group II soils are stabilized by an invasive metal-tolerant grass species, with Zn found as a mixture of octahedral (Fe oxides) and tetrahedral Mn oxides) adsorption complexes with a franklinite component. Soil erosion influences Zn speciation through the redistribution of Zn and soil particulates from Group I landscape positions to Group II soils. Despite Group II soils having the highest concentrations of CaCl-extractable Zn, they support metal-tolerant plant growth. The metal-tolerant plants are probably preferentially colonizing these areas due to better soil and nutrient conditions as a result of soil deposition from upslope Group I areas. Zinc concentration and speciation appears to not influence the colonization by metal-tolerant grasses, but the overall soil properties and erosion effects prevent the revegetation by native boreal forest species. PMID:27065416

  6. Do Forest Age and Soil Depth Affect Carbon and Nitrogen Adsorption in Mineral Horizons?

    NASA Astrophysics Data System (ADS)

    Spina, P. G.; Lovett, G. M.; Fuss, C. B.; Goodale, C. L.; Lang, A.; Fahey, T.

    2015-12-01

    Mineral soils retain large amounts of organic matter through sorption on the surfaces of mineral soils, the largest pools of carbon (C) and nitrogen (N) in the forests of the northeastern U.S. In addition to determining organic matter storage, adsorption and desorption processes are important controllers of runoff chemistry. We are studying adsorption dynamics of mineral soils collected from a chronosequence of hardwood forest sites in the White Mountains, NH to determine how soils vary in their DOM adsorption capacities as a function of effective C and N saturation. We hypothesize that forest age determines proximity to saturation because young forests may need to mine soil organic matter (SOM) in mineral soils to obtain nitrogen to meet growth demands, while the soils of older forests have had time to reaccumulate SOM, eventually reaching C and N saturation. Consequently, we expect adsorption capacities to first increase with forest age in young forests, as the trees mine C and N from mineral surfaces. They will then decrease with forest age in older forests as mining slows and C and N begin to re-accumulate. Batch experiments were conducted with mineral soil samples and dilutions of forest floor leachate. However, preliminary results from a mature forest site (about 100 years old), which we predicted to be a low point of C and N saturation from decades of mining, contradict expectations. Dissolved organic carbon (DOC) adsorption in its shallow mineral soil layers (0-3 cm below E or A horizons) are lower than younger sites ranging from 20 to about 40 years old. In addition to forest age, soil depths also affect N retention dynamics in forest soils. We hypothesized that deeper mineral soils might have greater adsorption capacities due to the fact that they are exposed to less DOC and DON leaching from organic layers and therefore less saturated. Results from the same mature forest site confirm this. Soils from 3-10 cm depth have more potential to adsorb DOC and

  7. Characterizing Soil Organic Matter Degradation Levels in Permafrost-affected Soils using Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Matamala, R.; Jastrow, J. D.; Calderon, F.; Liang, C.; Miller, R. M.; Ping, C. L.; Michaelson, G. J.; Hofmann, S.

    2014-12-01

    Diffuse-reflectance Fourier-transform mid-infrared spectroscopy (MidIR) was used to (1) investigate soil quality along a latitudinal gradient of Alaskan soils, and in combination with soil incubations, (2) to assess the relative lability of soil organic matter in the active layer and upper permafrost for some of those soils. Twenty nine sites were sampled along a latitudinal gradient (78.79 N to 55.35 N deg). The sites included 8 different vegetation types (moss/lichen, non-acidic and acidic tundra, shrub areas, deciduous forests, mixed forests, coniferous forests, and grassland). At each site, soils were separated by soil horizons and analyzed for pH, cation exchange capacity (CEC), organic and inorganic C, and total N. Samples were also scanned to obtain MidIR spectra, and ratios of characteristic bands previously suggested as indicators of organic matter quality or degradation level were calculated. Principal component analysis showed that axis 1 explained 70% of the variation and was correlated with the general Organic:Mineral ratio, soil organic C, total N, and CEC, but not with vegetation type. Axis 2 explained 25% of the variation and was correlated with most of the band ratios, with negative values for the condensation index (ratio of aromatic to aliphatic organic matter) and positive values for all humification ratios (HU1: ratio of aliphatic to polysaccharides; HU2: ratio of aromatics to polysaccharides; and HU3 ratio of lignin/phenols to polysaccharides) suggesting that axis 2 variations were related to differences in level of soil organic matter degradation. Active organic, active mineral and permafrost layers from selected tundra sites were incubated for two months at -1, 1, 4, 8 and 16 ⁰C. The same band ratios were correlated with total CO2 mineralized during the incubations. Data from 4⁰C showed that the cumulative respired CO2 from the active organic layer across all sites was negatively correlated with the HU1 humification ratio, suggesting

  8. Soil water content and soil disaggregation by disking affects PM10 emissions.

    PubMed

    Madden, Nicholaus M; Southard, Randal J; Mitchell, Jeff P

    2009-01-01

    Row crop agriculture in California's San Joaquin Valley is a major contributor of particulate matter <10 microm in aerodynamic diameter (PM10). The California Air Resources Board uses fixed PM10 emission values for various tillage operations to monitor and design attainment strategies. However, fixed emission values do not reflect emissions produced by a single implement operating under different soil conditions. This 2-yr study evaluated how PM10 mass concentrations (microg L(-1)) from disking change as a function of gravimetric soil water content (GWC), number of sequential diskings (D1, D2, D3), and the soil's weighted mean ped diameter (WMPD). Results showed PM10 increased logarithmically as the soil dried from a GWC of 14 to 4%. Average PM10 values at the lower GWCs were six to eight times greater than at the higher GWCs. Number of diskings also increased PM10, especially in drier soil. Below a GWC of 7%, PM10 for D3 was about twice that for D1. Despite strong correlations between more disking and lower WMPD, a lower WMPD did not always result in an increase in PM10. This underscored the role soil water plays in reducing PM10 at high GWCs despite low WMPDs from multiple diskings. Three-way interactions between GWC, disking, and PM10 showed, on average, that the magnitude of PM10 produced by D1 was 1.3 to 1.6 times lower than by D3, despite having insignificantly different GWC. Therefore, a disking operation can yield two different PM10 values under similar GWCs if the amount of soil disaggregation is different. Our results show that inclusion of soil parameters in PM10 emission estimates is essential to describing agriculture's role in air quality violations and to assess the value of proposed mitigation measures, such as conservation tillage. PMID:19141793

  9. Soil physical properties: Key factors for successful reclamation of disturbed landscapes

    NASA Astrophysics Data System (ADS)

    Krümmelbein, Julia; Raab, Thomas

    2013-04-01

    The practice of open cast mining, e.g. for lignite, results in major landscape disturbances and especially affects soils because relocation and subsequent mixing of naturally developed soil horizons leads to areas with extremely altered soil properties compared to the undisturbed conditions. Various reclamation measures are applied to recover the reconstructed landscape for different land use options. Major parts of the post mining landscapes are used for agriculture, agroforestry or silviculture, the remaining voids of the coal mines fill successively with groundwater after mine closure and are or will be used mainly for touristic and leisure purposes. Small proportions of the post mining areas are left for natural succession, or habitats for endangered flora and fauna are initiated. In reclamation research, many studies have focused on soil chemical and biological constraints of post mining substrates and investigated factors such as unsuitable pH, in many cases very low pH, (poor) nutrient contents and (poor) biological activity. But the initial and developing soil physical parameters and functions are also key factors for the success of reclamation practices. The soil water and gas balance influence strongly the suitability of a site for the intended future land use. The mechanical stability of the soil determines the rigidity of the pore system against deforming forces and thereby the persistence of soil functions, such as water and air permeability over time. The amendment of unfavourable (initial) soil physical properties is in most cases more complex and time-consuming than e.g. optimization of pH or fertilization with nutrients. Moreover, regarding the suitability of a site e.g. as a habitat for plants or microorganisms, poor physical pre-conditions can turn substrates with perfect nutrient contents and composition and pH into infertile locations of very low productivity. We show results of an on-going field study where the effects of different

  10. pH affects bacterial community composition in soils across the Huashan Watershed, China.

    PubMed

    Huang, Rui; Zhao, Dayong; Zeng, Jin; Shen, Feng; Cao, Xinyi; Jiang, Cuiling; Huang, Feng; Feng, Jingwei; Yu, Zhongbo; Wu, Qinglong L

    2016-09-01

    To investigate soil bacterial richness and diversity and to determine the correlations between bacterial communities and soil properties, 8 soil samples were collected from the Huashan watershed in Anhui, China. Subsequently, 454 high-throughput pyrosequencing and bioinformatics analyses were performed to examine the soil bacterial community compositions. The operational taxonomic unit richness of the bacterial community ranged from 3664 to 5899, and the diversity indices, including Chao1, Shannon-Wiener, and Faith's phylogenetic diversity ranged from 7751 to 15 204, 7.386 to 8.327, and 415.77 to 679.11, respectively. The 2 most dominant phyla in the soil samples were Actinobacteria and Proteobacteria. The richness and diversity of the bacterial community were positively correlated with soil pH. The Mantel test revealed that the soil pH was the dominant factor influencing the bacterial community. The positive modular structure of co-occurrence patterns at the genus level was discovered by network analysis. The results obtained in this study provide useful information that enhances our understanding of the effects of soil properties on the bacterial communities. PMID:27374919

  11. Trends in soil-vegetation dynamics in burned Mediterranean pine forests: the effects of soil properties

    NASA Astrophysics Data System (ADS)

    Wittenberg, L.; Malkinson, D.

    2009-04-01

    Fire can impact a variety of soil physical and chemical properties. These changes may result, given the fire severity and the local conditions, in decreased infiltration and increased runoff and erosion rates. Most of these changes are caused by complex interactions among eco-geomorphic processes which affect, in turn, the rehabilitation dynamics of the soil and the regeneration of the burnt vegetation. Following wildfire events in two forests growing on different soil types, we investigated runoff, erosion, nutrient export (specifically nitrogen and phosphorous) and vegetation recovery dynamics. The Biriya forest site, burned during the 2006 summer, is composed of two dominant lithological types: soft chalk and marl which are relatively impermeable. The rocks are usually overlain by relatively thick, up of to 80 cm, grayish-white Rendzina soil, which contains large amounts of dissolved carbonate. These carbonates serve as a limiting factor for vegetation growth. The planted forest in Biriya is comprised of monospecific stands of Pinus spp. and Cupressus spp. The Mt. Carmel area, which was last burned in the 2005 spring, represents a system of varied Mediterranean landscapes, differentiated by lithology, soils and vegetation. Lithology is mainly composed of limestone, dolomite, and chalk. The dominant soil is Brown Rendzina whilst in some locations Grey Rendzina and Terra Rossa can be found. The local vegetation is composed mainly of a complex of pine (Pinus halepensis), oak (Quercus calliprinos), Pistacia lentiscus and associations At each site several 3X3 m monitoring plots were established to collect runoff and sediment. In-plot vegetation changes were monitored by a sequence of aerial photographs captured using a 6 m pole-mounted camera. At the terra-rosa sites (Mt. Carmel) mean runoff coefficients were 2.18% during the first year after the fire and 1.6% in the second. Mean erosion rates also decreased, from 42 gr/m2 to 4 gr/m2. The recovering vegetation was

  12. Investigation of biochar effects as a non-structural BMP on soil erosional properties using a rainfall simulator

    NASA Astrophysics Data System (ADS)

    Khademalrasoul, Ataallah; Kuhn, Nikolaus; Hu, Yaxian; Vangsø Iversen, Bo; Heckrath, Goswin

    2014-05-01

    Recent studies have shown the potential of biochar for improving overall soil quality including soil aggregation and structure. Erodibility is an inherent soil property that amongst others is highly dependent on soil organic matter content which affects aggregate stability and crusting during runoff events. We hypothesized that erodibility is reduced in biochar-amended soils and tested this in controlled rainfall-runoff simulations. The specific objectives of our study were (1) to compare runoff and sediment generation between a biochar and an unamended control treatment on an arable sandy loam soil and (2) to determine the effect of the biochar treatment on SOC erodibility. A field experiment with eight plots was established at Risø, Denmark, in 2011; four biochar-amended and four unamended control plots. Biochar produced from birch wood at 500 ºC was applied at a rate of 2 kg m-2, and plots had been harrowed and ploughed twice to a depth of 25 cm prior to sampling. In the laboratory soil samples from (0-20 cm) were analyzed for aggregate stability and soil organic carbon (SOC) content. Soil erosional properties were measured during 3.5 hour rainfall simulations using a round flume setup. Artificial rain was applied with a FullJet nozzle at a rate of 30 mm h-1. Biochar-amended soils showed significantly lower runoff and erosion rates compared to unamended soils, and correspondingly runoff coefficients in biochar-treated soils were lower than in control soils. Less SOC was eroded from biochar-amended soils resulting in lower SOC enrichment ratios in sediment from biochar-amended soils compared to unamended control soils. The results indicated that biochar already after a relatively short incubation period in the field can lead to reduced erodibility due to improved soil aggregation and aggregate stability. The results further suggested a direct biochar effect on surface roughness which leading to lower erosion.

  13. Soil survey and resource inventory guide for dynamic soil properties and soil change

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Data and information about how soils change are needed by producers, land managers, and decision makers in order to plan for long-term productivity, interpret indicators used in monitoring and assessments, and manage human impacts on soil. In order to meet these needs, the National Cooperative Soil ...

  14. EFFECT OF SOIL PROPERTIES ON LEAD BIOAVAILABILITY AND TOXCITY TO EARTHWORMS

    EPA Science Inventory

    Soil properties are important factors modifying metal bioavailability to ecological receptors. Twenty-one soils with a wide range of soil properties were amended with a single concentration of Pb (2000 mg/kg) to determine the effects of soil properties on Pb bioavailability and ...

  15. Streptococcus suis sorption on agricultural soils: role of soil physico-chemical properties.

    PubMed

    Zhao, Wenqiang; Liu, Xing; Huang, Qiaoyun; Cai, Peng

    2015-01-01

    Understanding pathogen sorption on natural soil particles is crucial to protect public health from soilborne and waterborne diseases. Sorption of pathogen Streptococcus suis on 10 agricultural soils was examined, and its correlations with soil physico-chemical properties were also elucidated. S. suis sorption isotherms conformed to the linear equation, with partition coefficients (Ks) ranging from 12.7 mL g(-1) to 100.1 mL g(-1). Bacteria were observed to sorb on the external surfaces of soil aggregates by scanning electron microscopy. Using Pearson correlation and linear regression analysis, solution pH was found to have significant negative correlations with Ks. Stepwise multiple regression and path analysis revealed that pH and cation exchange capacity (CEC) were the main factors influencing sorption behaviors. The obtained overall model (Ks=389.6-45.9×pH-1.3×CEC, R(2)=0.943, P<0.001) can accurately predict Ks values. However, the variability in Ks was less dependent on soil organic matter, specific surface area, soil texture and zeta potential, probably due to the internal-surface shielding phenomenon of soil aggregates. Additionally, the sorption trends cannot be interpreted by interaction energy barriers calculated using the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory, suggesting the limits of DLVO theory in describing pathogen sorption on natural soils. Our results also indicated soil pH and CEC should be preferentially considered when modeling S. suis sorption process. PMID:24968305

  16. Microwave Remote Sensing of Soil Moisture for Estimation of Soil Properties

    NASA Technical Reports Server (NTRS)

    Mattikalli, Nandish M.; Engman, Edwin T.; Jackson, Thomas J.

    1997-01-01

    Surface soil moisture dynamics was derived using microwave remote sensing, and employed to estimate soil physical and hydraulic properties. The L-band ESTAR radiometer was employed in an airborne campaign over the Little Washita watershed, Oklahoma during June 10-18, 1992. Brightness temperature (TB) data were employed in a soil moisture inversion algorithm which corrected for vegetation and soil effects. Analyses of spatial TB and soil moisture dynamics during the dry-down period revealed a direct relationship between changes in TB, soil moisture and soil texture. Extensive regression analyses were carried out which yielded statistically significant quantitative relationships between ratio of percent sand to percent clay (RSC, a term derived to quantify soil texture) and saturated hydraulic conductivity (Ksat) in terms of change components of TB and surface soil moisture. Validation of results indicated that both RSC and Ksat can be estimated with reasonable accuracy. These findings have potential applications for deriving spatial distributions of RSC and Ksat over large areas.

  17. Changes in the properties of soils in a solonetz soil complex thirty years after reclamation

    NASA Astrophysics Data System (ADS)

    Kalinichenko, V. P.; Sharshak, V. K.; Mironchenko, S. F.; Chernenko, V. V.; Ladan, E. P.; Genev, E. D.; Illarionov, V. V.; Udalov, A. V.; Udalov, V. V.; Kippel, E. V.

    2014-04-01

    The long-term (30 year) dynamics of a solonetz soil complex composed of solonetzic light chestnut soils and chestnut solonetzes under standard conditions and with the application of agromeliorative measures are considered. When the standard zonal agricultural practice is used, the soils of the solonetzic complex have unfavorable agrophysical, chemical, and physicochemical properties and low productivity. After 30 years of the standard three-level tillage of the soils to a depth of 40-45 cm, the productivity of the biogeocenosis decreased. Thirty years after a single rotary-milling subsoil treatment of the 20- to 45-cm soil layer using a milling tool FS-1.3, there were no morphological features pointing to the restoration of the solonetzic process. The humus content in the 0-to 20-cm and 20-to 40-cm soil layers was 2.3 and 1.7%, respectively; the content of adsorbed Na+ in the 20-to 30-cm layer was 11.6% of the total exchange capacity, or 38% lower than its content in the reference soil. The additional yield reached 30-70% and more of that obtained with the standard agricultural technology used during the whole period under investigation. The method of systems biogeotechnology (systems bio-geo engineering) is proposed as a method for the preventive control of soil evolution and the maintenance of the stability and high productivity of the soil cover.

  18. Climate, soil texture, and soil types affect the contributions of fine-fraction-stabilized carbon to total soil organic carbon in different land uses across China.

    PubMed

    Cai, Andong; Feng, Wenting; Zhang, Wenju; Xu, Minggang

    2016-05-01

    Mineral-associated organic carbon (MOC), that is stabilized by fine soil particles (i.e., silt plus clay, <53 μm), is important for soil organic carbon (SOC) persistence and sequestration, due to its large contribution to total SOC (TSOC) and long turnover time. Our objectives were to investigate how climate, soil type, soil texture, and agricultural managements affect MOC contributions to TSOC in China. We created a dataset from 103 published papers, including 1106 data points pairing MOC and TSOC across three major land use types: cropland, grassland, and forest. Overall, the MOC/TSOC ratio ranged from 0.27 to 0.80 and varied significantly among soil groups in cropland, grassland, and forest. Croplands and forest exhibited significantly higher median MOC/TSOC ratios than in grassland. Moreover, forest and grassland soils in temperate regions had higher MOC/TSOC ratios than in subtropical regions. Furthermore, the MOC/TSOC ratio was much higher in ultisol, compared with the other soil types. Both the MOC content and MOC/TSOC ratio were positively correlated with the amount of fine fraction (silt plus clay) in soil, highlighting the importance of soil texture in stabilizing organic carbon across various climate zones. In cropland, different fertilization practices and land uses (e.g., upland, paddy, and upland-paddy rotation) significantly altered MOC/TSOC ratios, but not in cropping systems (e.g., mono- and double-cropping) characterized by climatic differences. This study demonstrates that the MOC/TSOC ratio is mainly driven by soil texture, soil types, and related climate and land uses, and thus the variations in MOC/TSOC ratios should be taken into account when quantitatively estimating soil C sequestration potential of silt plus clay particles on a large scale. PMID:26905446

  19. Cone-penetrometer exploration of sinkholes: Stratigraphy and soil properties

    SciTech Connect

    Bloomberg, D.; Upchurch, S.B.; Hayden, M.L. ); Williams, R.C. )

    1988-10-01

    Four sinkholes with varying surficial expressions were subjected to detailed stratigraphic and soil analysis by means of Standard Penetration Tests (SPT) and Electric Friction Cone Penetration Tests (CPT) in order to evaluate applications of CPT to sinkhole investigations. Although widely used, SPT data are of limited value and difficult to apply to sinkhole mapping. CPT is sensitive to minor lithologic variability and is superior to SPT as a cost-effective technique for determining geotechnical properties of sinkholes. The effectiveness of CPT data results from the force measurements made along the sleeve of the cone. The friction ratio (ratio of sleeve to tip resistance) is a good indicator of soil stratigraphy and properties. By smoothing the friction-ratio data, general stratigraphy and changes in soil properties are easily identified. Stratigraphy of the sinks has been complicated by intense weathering, karstification and marine transgressions. The resulting deposits include five stratigraphic units. 1 and 2 represent Plio-Pleistocene marine sediments with Unit 2 being the zone of soil clay accumulation. 3 and 4 are horizons residual from Miocene strata and indicate an episode of karstification prior to deposition of Units 1 and 2. CPT provides sufficient information for recognition of sinkhole stratigraphy and geotechnical properties. When coupled with laboratory soil analysis, CPT provides unique information about sinkhole geometry and dynamics. In contrast, SPT indicates general, inconclusive trends.

  20. A review of the distribution coefficients of trace elements in soils: influence of sorption system, element characteristics, and soil colloidal properties.

    PubMed

    Shaheen, Sabry M; Tsadilas, Christos D; Rinklebe, Jörg

    2013-12-01

    Knowledge about the behavior and reactions of separate soil components with trace elements (TEs) and their distribution coefficients (Kds) in soils is a key issue in assessing the mobility and retention of TEs. Thus, the fate of TEs and the toxic risk they pose depend crucially on their Kd in soil. This article reviews the Kd of TEs in soils as affected by the sorption system, element characteristics, and soil colloidal properties. The sorption mechanism, determining factors, favorable conditions, and competitive ions on the sorption and Kd of TEs are also discussed here. This review demonstrates that the Kd value of TEs does not only depend on inorganic and organic soil constituents, but also on the nature and characteristics of the elements involved as well as on their competition for sorption sites. The Kd value of TEs is mainly affected by individual or competitive sorption systems. Generally, the sorption in competitive systems is lower than in mono-metal sorption systems. More strongly sorbed elements, such as Pb and Cu, are less affected by competition than mobile elements, such as Cd, Ni, and Zn. The sorption preference exhibited by soils for elements over others may be due to: (i) the hydrolysis constant, (ii) the atomic weight, (iii) the ionic radius, and subsequently the hydrated radius, and (iv) its Misono softness value. Moreover, element concentrations in the test solution mainly affect the Kd values. Mostly, values of Kd decrease as the concentration of the included cation increases in the test solution. Additionally, the Kd of TEs is controlled by the sorption characteristics of soils, such as pH, clay minerals, soil organic matter, Fe and Mn oxides, and calcium carbonate. However, more research is required to verify the practical utilization of studying Kd of TEs in soils as a reliable indicator for assessing the remediation process of toxic metals in soils and waters. PMID:24168932

  1. Soil biota can change after exotic plant invasion: Does this affect ecosystem processes?

    USGS Publications Warehouse

    Belnap, J.; Phillips, S.L.; Sherrod, S.K.; Moldenke, A.

    2005-01-01

    Invasion of the exotic annual grass Bromus tectorum into stands of the native perennial grass Hilaria jamesii significantly reduced the abundance of soil biota, especially microarthropods and nematodes. Effects of invasion on active and total bacterial and fungal biomass were variable, although populations generally increased after 50+ years of invasion. The invasion of Bromus also resulted in a decrease in richness and a species shift in plants, microarthropods, fungi, and nematodes. However, despite the depauperate soil fauna at the invaded sites, no effects were seen on cellulose decomposition rates, nitrogen mineralization rates, or vascular plant growth. When Hilaria was planted into soils from not-invaded, recently invaded, and historically invaded sites (all currently or once dominated by Hilaria), germination and survivorship were not affecte