WorldWideScience

Sample records for rangeland soils influence

  1. Criterion I: Soil and water conservation on rangelands [Chapter 2

    Science.gov (United States)

    Michael G. (Sherm) Karl; Paul T. Tueller; Gerald E. Schuman; Mark R. Vinson; James L. Fogg; Ronald W. Shafer; David A. Pyke; D. Terrance Booth; Steven J. Borchard; William G. Ypsilantis; Richard H. Barrett

    2010-01-01

    The Sustainable Rangelands Roundtable (SRR) has explicitly included conservation and maintenance of soil and water resources as a criterion of rangeland sustainability. Within the soil/water criterion, 10 indicators ­ five soil-based and five water-based - were developed through the expert opinions of rangeland scientists, rangeland management agency personnel, non-...

  2. Influence of livestock density on the amount and structure of soil microbial communities in rangelands of SW Spain

    Science.gov (United States)

    Anguita, Manuel; Pulido, Manuel; Schnabel, Susanne; Lavado-Contador, Francisco; Ortega, Raul; Soriano, Miguel; Miralles, Isabel

    2017-04-01

    Rangelands (namely dehesas and montados) occupy more than 90,000 km2 of land in SW Iberian Peninsula. Their natural pastures are permanently grazed by 13 millions of domestic animals. The persistence of soils of high quality is a key factor for keeping their environmental and economic sustainability. The role of soil microbial communities in the biodegradation processes of organic compounds is essential to ensure soil fertility in this kind of human-induced ecosystems. Nevertheless, there are few studies dealing the effects of livestock grazing on soil microbial communities. The main goal of this study is therefore to assess the amount and structure of soil microbial communities in rangelands of SW Spain by comparing different grazing intensities. The study was carried out in 4 fenced areas (sampling sites) belonging to privately-owned farms under different grazing intensities: low, moderate and high. One area excluded to grazing for more than 40 years (located in the Monfragüe National Park, Extremadura) was used as reference sampling site. A total number of 30 soil samples (6 each site) were collected in comparable areas with the same lithology and very similar topographical features. Commercial kit to extract DNA from these soil samples was used for metagenomic analysis. We conducted a sequencing of the amplicons V4-V5 of the 16S rRNA gene with Next-Generation Sequencing (NGS) Illumina MiSeq platform and a relative quantity of bacteria and fungi were accomplished by quantitative qPCR of rRNA 16S and ITS1-5.8S, respectively. The results showed that soils with a high livestock density had the highest content of bacteria per gram of soil (4.77E+09), followed by soils with moderate (3.32E+09) and low livestock density (2.80E+09). The lowest content of microorganisms was found in soils excluded to grazing (2.38E+09). However, soils with moderate and low livestock density showed the greatest amount of fungi per gram of soil (2.31E+10 and 2.22E+10, respectively) and

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

    Directory of Open Access Journals (Sweden)

    Romeu de Souza Werner

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

  4. Land use and soil organic matter in South Africa 1: A review on spatial variability and the influence of rangeland stock production

    Directory of Open Access Journals (Sweden)

    Pearson N.S. Mnkeni

    2011-05-01

    Full Text Available Degradation of soil as a consequence of land use poses a threat to sustainable agriculture in South Africa, resulting in the need for a soil protection strategy and policy. Development of such a strategy and policy require cognisance of the extent and impact of soil degradation processes. One of the identified processes is the decline of soil organic matter, which also plays a central role in soil health or quality. The spatial variability of organic matter and the impact of grazing and burning under rangeland stock production are addressed in this first part of the review. Data from uncoordinated studies showed that South African soils have low organic matter levels. About 58% of soils contain less than 0.5% organic carbon and only 4% contain more than 2% organic carbon. Furthermore, there are large differences in organic matter content within and between soil forms, depending on climatic conditions, vegetative cover, topographical position and soil texture. A countrywide baseline study to quantify organic matter contents within and between soil forms is suggested for future reference. Degradation of rangeland because of overgrazing has resulted in significant losses of soil organic matter, mainly as a result of lower biomass production. The use of fire in rangeland management decreases soil organic matter because litter is destroyed by burning. Maintaining or increasing organic matter levels in degraded rangeland soils by preventing overgrazing and restricting burning could contribute to the restoration of degraded rangelands. This restoration is of the utmost importance because stock farming uses the majority of land in South Africa.

  5. Impact of Rangeland Degradation on Soil Physical, Chemical

    African Journals Online (AJOL)

    In terms of impacts from soil compaction, Abdel-Megid et al, (1987) reported reduced water infiltration and aeration, while Van der westhuizen et al., (1999) found poor plant respiration and soil seed germination unless the soil crust is broken. Soil compaction also enhanced encroachment in eastern rangelands of Ethiopia ...

  6. Rangeland health assessment - The key to understanding and assessing rangeland soil health in the Northern Great Plains

    Science.gov (United States)

    As the science related to soil and rangeland health evolves, so do their protocols and assessment methodologies. Rangeland health assessments consist of evaluating how well ecological processes such as the water cycle, energy flow and nutrient cycling are functioning at a site. Soil health is the ca...

  7. Advances in modeling soil erosion after disturbance on rangelands

    Science.gov (United States)

    Research has been undertaken to develop process based models that predict soil erosion rate after disturbance on rangelands. In these models soil detachment is predicted as a combination of multiple erosion processes, rain splash and thin sheet flow (splash and sheet) detachment and concentrated flo...

  8. The rangeland management and soil health connection

    Science.gov (United States)

    Soil health is defined as the capacity of soil to function and provide ecosystem services to society. The importance of managing for the improvement and maintenance of soil health transcends political boundaries, generations, societies and languages. The challenge of communicating soil health conc...

  9. Physicochemical characteristics of communal rangeland soils along ...

    African Journals Online (AJOL)

    This study investigated the relative association of surface (0–20 cm) soil physicochemical properties, viz. electrical conductivity, cation exchange capacity (CEC), soil organic carbon, available phosphorus, particle size composition, soil aggregate stability and microbial respiration, along a toposequence in two vegetation ...

  10. Soil degradation in wooded rangelands of southwest Spain

    Science.gov (United States)

    Schnabel, S.; Lavado Contador, J. F.; Gómez Gutiérrez, Á.

    2009-04-01

    The paper presents a review on soil degradation studies carried out since 1990 in wooded rangelands in Extremadura. In the semiarid and subhumid parts of the south-western Iberian Peninsula open evergreen woodlands dominated by Quercus species are widespread (dehesas and montados). They are composed of grasslands with a varying degree of tree cover, ranging from treeless to more than 80 individuals per hectare. In some areas shrubs form a third component of the vegetation. Dehesas are subject to a complex exploitation system with agro-silvo-pastoral land use. The dominant soil degradation phenomena include different forms of water erosion and physical and biological degradation. Regarding soil erosion and surface hydrology, research has been carried out at different spatial scales. Sheetwash and overland flow were investigated along hillslopes and in microplots, whereas gully erosion and runoff production were monitored in small experimental catchments. Recently, physical and biological degradation has been studied in a large number of farms, representing the most important types of rangelands in the region of Extremadura. This included a rapid appraisal of degradation features, the determination of soil properties and a study on the distribution and activity of gullies. Soil degradation varies strongly with regard to the natural factors, but also with respect to land use and management. Sheetwash (interrill erosion) is the dominant process on hillslopes, with a mean soil loss rate of 0.63 t ha-1. However rainfall variation and land management, especially livestock density, produce changes in soil cover. With low to moderate livestock densities and during prolonged periods with low rainfall (droughts), the vegetation cover may be strongly reduced, provoking high soil losses, whereas during normal or humid periods interrill erosion is low. Excessive stocking rates may exacerbate sheetwash, producing severe soil degradation, regardless of rainfall conditions. In

  11. The Rangeland Hydrology and Erosion Model: A dynamic approach for predicting soil loss on rangelands

    Science.gov (United States)

    In this study we present the improved Rangeland Hydrology and Erosion Model (RHEM V2.3), a process-based erosion prediction tool specific for rangeland application. The article provides the mathematical formulation of the model and parameter estimation equations. Model performance is assessed agains...

  12. USDA internet tool to estimate runoff and soil loss on rangelands: rangelands hydrology and erosion model

    Science.gov (United States)

    Rangelands are the most dominant land cover type in the United States (770 million acres) with approximately 53% of the nation’s rangelands owned and managed by the private sector, while approximately 43% are managed by the federal government. Information on the type, extent, and spatial location of...

  13. Disaggregation of Soil Map Units for Improved Ecological Site Mapping in Rangelands

    Science.gov (United States)

    Rangeland soils are often mapped with soil map units consisting of associations, complexes, and undifferentiated groups composed of varied soil components. Because different components may be related to different ecological sites, the unmapped heterogeneity within map units limits the potential uses...

  14. Effects of Management on Soil Carbon Pools in California Rangeland Ecosystems

    Science.gov (United States)

    Silver, W. L.; Ryals, R.; Lewis, D. J.; Creque, J.; Wacker, M.; Larson, S.

    2008-12-01

    Rangeland ecosystems managed for livestock production represent the largest land-use footprint globally, covering more than one-quarter of the world's land surface (Asner et al. 2004). In California, rangelands cover an estimated 17 million hectares or approximately 40% of the land area (FRAP 2003). These ecosystems have considerable potential to sequester carbon (C) in soil and offset greenhouse gas emissions through changes in land management practices. Climate policies and C markets may provide incentives for rangeland managers to pursue strategies that optimize soil C storage, yet we lack a thorough understanding of the effects of management on soil C pools in rangelands over time and space. We sampled soil C pools on rangelands in a 260 km2 region of Marin and Sonoma counties to determine if patterns in soil C storage exist with management. Replicate soil samples were collected from 35 fields that spanned the dominant soil orders, plant communities, and management practices in the region while controlling for slope and bioclimatic zone (n = 1050). Management practices included organic amendments, intensive (dairy) and extensive (other) grazing practices, and subsoiling. Soil C pools ranged from approximately 50 to 140 Mg C ha-1 to 1 m depth, with a mean of 99 ± 22 (sd) Mg C ha-1. Differences among sites were due primarily to C concentrations, which exhibited a much larger coefficient of variation than bulk density at all depths. There were no statistically significant differences among the dominant soil orders. Subsoiling appeared to significantly increase soil C content in the top 50 cm, even though subsoiling had only occurred for the first time the previous Nov. Organic amendments also appeared to greatly increase soil C pools, and was the dominant factor that distinguished soil C pools in intensive and extensive land uses. Our results indicate that management has the potential to significantly increase soil C pools. Future research will determine the

  15. Developing a parameterization approach of soil erodibility for the Rangeland Hydrology and Erosion Model (RHEM)

    Science.gov (United States)

    Soil erodibility is a key factor for estimating soil erosion using physically based models. In this study, a new parameterization approach for estimating erodibility was developed for the Rangeland Hydrology and Erosion Model (RHEM). The approach uses empirical equations that were developed by apply...

  16. Developing soil erodibility prediction equations for the Rangeland Hydrology and Erosion Model (RHEM)

    Science.gov (United States)

    Soil erodibility is a key factor for estimating soil erosion using physically based models. In this study, a new parameterization approach for estimating erodibility was developed for the Rangeland Hydrology and Erosion Model (RHEM). The approach uses empirical equations that were developed by apply...

  17. The Rangeland Hydrology and Erosion Model: A Dynamic Approach for Predicting Soil Loss on Rangelands

    Science.gov (United States)

    Hernandez, Mariano; Nearing, Mark A.; Al-Hamdan, Osama Z.; Pierson, Frederick B.; Armendariz, Gerardo; Weltz, Mark A.; Spaeth, Kenneth E.; Williams, C. Jason; Nouwakpo, Sayjro K.; Goodrich, David C.; Unkrich, Carl L.; Nichols, Mary H.; Holifield Collins, Chandra D.

    2017-11-01

    In this study, we present the improved Rangeland Hydrology and Erosion Model (RHEM V2.3), a process-based erosion prediction tool specific for rangeland application. The article provides the mathematical formulation of the model and parameter estimation equations. Model performance is assessed against data collected from 23 runoff and sediment events in a shrub-dominated semiarid watershed in Arizona, USA. To evaluate the model, two sets of primary model parameters were determined using the RHEM V2.3 and RHEM V1.0 parameter estimation equations. Testing of the parameters indicated that RHEM V2.3 parameter estimation equations provided a 76% improvement over RHEM V1.0 parameter estimation equations. Second, the RHEM V2.3 model was calibrated to measurements from the watershed. The parameters estimated by the new equations were within the lowest and highest values of the calibrated parameter set. These results suggest that the new parameter estimation equations can be applied for this environment to predict sediment yield at the hillslope scale. Furthermore, we also applied the RHEM V2.3 to demonstrate the response of the model as a function of foliar cover and ground cover for 124 data points across Arizona and New Mexico. The dependence of average sediment yield on surface ground cover was moderately stronger than that on foliar cover. These results demonstrate that RHEM V2.3 predicts runoff volume, peak runoff, and sediment yield with sufficient accuracy for broad application to assess and manage rangeland systems.

  18. Modeling climate change effects on runoff and soil erosion in southeastern Arizona rangelands and implications for mitigation with rangeland conservation practices

    Science.gov (United States)

    Climate change is expected to impact runoff and soil erosion on rangelands in the southwestern United States. This study was done to evaluate the potential impacts of precipitation changes on soil erosion and surface runoff in southeastern Arizona using seven GCM models with three emission scenarios...

  19. Runoff and soil erosion from two rangeland sites

    Science.gov (United States)

    Historically over 50 years of rainfall/runoff research using rainfall simulators has been conducted at various rangeland sites in the West, however these sites rarely have consecutive yearly measurements. This limits the understanding of dynamic annual conditions and the interactions of grazing, pla...

  20. Comparison of different methods of image analysis for quantifying bare soil in rangelands

    Science.gov (United States)

    Pulido Fernández, M.; Lavado Contador, J. F.; Schnabel, S.; Gómez Gutiérrez, Á.

    2009-04-01

    Many authors emphasize the importance of vegetation in maintaining low levels of soil loss by means of its positive influence in reducing erosion. In some low-vegetated Mediterranean rangelands, especially those with high livestock densities, water erosion can ultimately lead to a partial or total loss of soils, particularly at the beginning of the rainy season, when the surface cover is reduced after the dry summer period. In relation with this, it is essential to develop accurate methods allowing the quantification of bare soil which, in turn, can inform about the influence of different livestock management alternatives over the land system. The main goal of this work is the comparison of the ability of various pixel-based as well as object-oriented methods of image classification for the quantification of bare soil at a fine spatial resolution. The study area is a farm located in a woody rangeland (dehesa) in SW Spain covering a surface area of 1,024 hectare. A three bands (RGB) orthophoto image with a pixel size of 0,4 metres was used, together with its brightness component, to compare the classification of bare soil vs covered soil by means of the following methods: unsupervised classification (k-means algorithm), supervised classification (maximum likelihood classification, minimum distance or nearest neighbour and Mahalanobis distance) and object oriented classification through a multiresolution segmentation. The results of classification were tested using 700 to 1000 points of field validation. Different combinations of image layers as well as validation algorithms were applied to assess for the better classification results. The best unsupervised classification was obtained from a combination of the RGB layers with the brightness component of the image. A total of 93.1 % of the field data were correctly classified and the Area Under the Curve (AUC) obtained with the ROC (Receiving Operating Characteristic) validation technique amounted to 0.91. With this

  1. Scientific background for soil monitoring on National Forests and Rangelands: workshop proceedings; April 29-30, 2008; Denver, CO

    Science.gov (United States)

    Deborah Page-Dumroese; Daniel Neary; Carl Trettin

    2010-01-01

    This workshop was developed to determine the state-of-the-science for soil monitoring on National Forests and Rangelands. We asked international experts in the field of soil monitoring, soil monitoring indicators, and basic forest soil properties to describe the limits of our knowledge and the ongoing studies that are providing new information. This workshop and the...

  2. Field soil aggregate stability kit for soil quality and rangeland health evaluations

    Science.gov (United States)

    Herrick, J.E.; Whitford, W.G.; de Soyza, A. G.; Van Zee, J. W.; Havstad, K.M.; Seybold, C.A.; Walton, M.

    2001-01-01

    Soil aggregate stability is widely recognized as a key indicator of soil quality and rangeland health. However, few standard methods exist for quantifying soil stability in the field. A stability kit is described which can be inexpensively and easily assembled with minimal tools. It permits up to 18 samples to be evaluated in less than 10 min and eliminates the need for transportation, minimizing damage to soil structure. The kit consists of two 21??10.5??3.5 cm plastic boxes divided into eighteen 3.5??3.5 cm sections, eighteen 2.5-cm diameter sieves with 1.5-mm distance openings and a small spatula used for soil sampling. Soil samples are rated on a scale from one to six based on a combination of ocular observations of slaking during the first 5 min following immersion in distilled water, and the percent remaining on a 1.5-mm sieve after five dipping cycles at the end of the 5-min period. A laboratory comparison yielded a correlation between the stability class and percent aggregate stability based on oven dry weight remaining after treatment using a mechanical sieve. We have applied the method in a wide variety of agricultural and natural ecosystems throughout western North America, including northern Mexico, and have found that it is highly sensitive to differences in management and plant community composition. Although the field kit cannot replace the careful laboratory-based measurements of soil aggregate stability, it can clearly provide valuable information when these more intensive procedures are not possible.

  3. Managing Semi-Arid Rangelands for Carbon Storage: Grazing and Woody Encroachment Effects on Soil Carbon and Nitrogen.

    Science.gov (United States)

    Yusuf, Hasen M; Treydte, Anna C; Sauerborn, Jauchim

    2015-01-01

    High grazing intensity and wide-spread woody encroachment may strongly alter soil carbon (C) and nitrogen (N) pools. However, the direction and quantity of these changes have rarely been quantified in East African savanna ecosystem. As shifts in soil C and N pools might further potentially influence climate change mitigation, we quantified and compared soil organic carbon (SOC) and total soil nitrogen (TSN) content in enclosures and communal grazing lands across varying woody cover i.e. woody encroachment levels. Estimated mean SOC and TSN stocks at 0-40 cm depth varied across grazing regimes and among woody encroachment levels. The open grazing land at the heavily encroached site on sandy loam soil contained the least SOC (30 ± 2.1 Mg ha-1) and TSN (5 ± 0.57 Mg ha-1) while the enclosure at the least encroached site on sandy clay soil had the greatest mean SOC (81.0 ± 10.6 Mg ha-1) and TSN (9.2 ± 1.48 Mg ha-1). Soil OC and TSN did not differ with grazing exclusion at heavily encroached sites, but were twice as high inside enclosure compared to open grazing soils at low encroached sites. Mean SOC and TSN in soils of 0-20 cm depth were up to 120% higher than that of the 21-40 cm soil layer. Soil OC was positively related to TSN, cation exchange capacity (CEC), but negatively related to sand content. Our results show that soil OC and TSN stocks are affected by grazing, but the magnitude is largely influenced by woody encroachment and soil texture. We suggest that improving the herbaceous layer cover through a reduction in grazing and woody encroachment restriction are the key strategies for reducing SOC and TSN losses and, hence, for climate change mitigation in semi-arid rangelands.

  4. Managing Semi-Arid Rangelands for Carbon Storage: Grazing and Woody Encroachment Effects on Soil Carbon and Nitrogen

    Science.gov (United States)

    Yusuf, Hasen M.; Treydte, Anna C.; Sauerborn, Jauchim

    2015-01-01

    High grazing intensity and wide-spread woody encroachment may strongly alter soil carbon (C) and nitrogen (N) pools. However, the direction and quantity of these changes have rarely been quantified in East African savanna ecosystem. As shifts in soil C and N pools might further potentially influence climate change mitigation, we quantified and compared soil organic carbon (SOC) and total soil nitrogen (TSN) content in enclosures and communal grazing lands across varying woody cover i.e. woody encroachment levels. Estimated mean SOC and TSN stocks at 0–40 cm depth varied across grazing regimes and among woody encroachment levels. The open grazing land at the heavily encroached site on sandy loam soil contained the least SOC (30 ± 2.1 Mg ha-1) and TSN (5 ± 0.57 Mg ha-1) while the enclosure at the least encroached site on sandy clay soil had the greatest mean SOC (81.0 ± 10.6 Mg ha-1) and TSN (9.2 ± 1.48 Mg ha-1). Soil OC and TSN did not differ with grazing exclusion at heavily encroached sites, but were twice as high inside enclosure compared to open grazing soils at low encroached sites. Mean SOC and TSN in soils of 0–20 cm depth were up to 120% higher than that of the 21–40 cm soil layer. Soil OC was positively related to TSN, cation exchange capacity (CEC), but negatively related to sand content. Our results show that soil OC and TSN stocks are affected by grazing, but the magnitude is largely influenced by woody encroachment and soil texture. We suggest that improving the herbaceous layer cover through a reduction in grazing and woody encroachment restriction are the key strategies for reducing SOC and TSN losses and, hence, for climate change mitigation in semi-arid rangelands. PMID:26461478

  5. Simulating soil moisture change in a semiarid rangeland watershed with a process-based water-balance model

    Science.gov (United States)

    Howard Evan Canfield; Vicente L. Lopes

    2000-01-01

    A process-based, simulation model for evaporation, soil water and streamflow (BROOK903) was used to estimate soil moisture change on a semiarid rangeland watershed in southeastern Arizona. A sensitivity analysis was performed to select parameters affecting ET and soil moisture for calibration. Automatic parameter calibration was performed using a procedure based on a...

  6. Spatial heterogeneity of aggregate stability and soil carbon in semi-arid rangeland.

    Science.gov (United States)

    Bird, S B; Herrick, J E; Wander, M M; Wright, S F

    2002-01-01

    To measure and manage for C sequestration in heterogeneous rangeland systems, we need to more fully understand spatial patterns of soil resources. Spatial distributions of aggregate stability and soil carbon were investigated in a semiarid rangeland in New Mexico, USA. Soil was analyzed from plant interspaces, black grama (Bouteloua eriopoda (Torr.) Torr.), and mesquite (Prosopis glandulosa Torr.) in a landscape-replicated study. Aggregate stability at the 250 microm scale, carbonate C, organic C and N, C:N ratio, and glomalin, were all highest under mesquite. Soil C:N ratio was the best predictor of aggregate stability. Estimates of metric tons of C per hectare in the top 10 cm were highly variable at patch and landscape scales, varying from 4.2 to 10.5 under mesquite and from 3.0 to 7.0 in interspaces. High variability of aggregate stability and soil C has important implications for C sequestration. We argue that this multi-scale soil heterogeneity must be considered when measuring and managing for C sequestration.

  7. Comparing soil aggregate stability at different grazing intensities (case study: Bardasiab rangeland, Fereidounshahr

    Directory of Open Access Journals (Sweden)

    M Mollaei

    2012-06-01

    Full Text Available Soil quality, aggregate stability and erosion sensibility are affected by different range management practices. This research aimed to evaluate the relationships between soil organic carbon, mean weight diameter (MWD and aggregate size distribution in the surface soil layer (0- 20 cm of various range sites with different grazing intensities (non, slightly and heavily grazed in Bardasiab rangeland, Feridounshahr, Isfahan province. Stratified random sampling method was used to collect soil samples along the established transects. Some physical and chemical properties of soil samples such as texture, electrical conductivity (EC, organic carbon (OC, MWD and sodium absorption ratio (SAR were measured in the soil laboratory. Simple linear regression and One-way ANOVA followed by the Fisher’s LSD test were used to analyze the data. Results of regression analysis showed that MWD and OC of the soil samples were significantly correlated ( α =1%, R 2 = 61.3 %. The soil MWD values of range sites with various grazing intensities were significantly different ( α =5%. Organic carbon was increased and SAR was decreased in the sites located inside exclosures, which lead to higher soil MWD. Aggregate size distribution among various sites were significantly different ( α =5% only for the aggregate smaller than 0.25 mm. Soil aggregates sizes between non-grazed and heavily grazed sites were also significantly different only for the size ranges of 4- 8 mm α =5%, ( and less than 0.25 mm α=1% (. In addition, macro aggregates increased and micro aggregates decreased in range sites with no or slight grazing intensity, respectively as these sites experienced low trampling and increased litter and organic carbons. Soil aggregate stability can therefore be used as an appropriate indicator for monitoring the impact of different management practices on rangeland soil quality and health.

  8. Investigating the Effect of Biological Crusts on Some Biological Properties of Soil (Case Study: Qare Qir Rangelands of Golestan Province

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    J. Kakeh

    2016-09-01

    Full Text Available Introduction: Physical and biological soil crusts are the principal types of soil crusts. Physical and biological soil crusts are distributed in arid, semi-arid and sub-humid regions which constitute over 40% of the earth terrestrial surface. Biological soil crusts (BSCs result from an intimate association between soil particles and cyanobacteria, algae, fungi, lichens and mosses in different proportions which live on the surface, or in the immediately uppermost millimeters of soil. Some of the functions that BSCs influences include: water absorption and retention, nutrient retention, Carbon and nitrogen fixation, biological activate and hydrologic Status. BSCs are important from the ecological view point and their effects on the environment, especially in rangeland, and desert ecosystems and this caused which researchers have a special attention to this component of the ecosystems more than before. Materials and Methods: This study carried out in the Qara Qir rangelands of Golestan province, northeast of Iran (37º15′ - 37º23′ N &54º33′ -54º39′ E, to investigate the effects of BSCs on some of soil biological properties. Four sites including with and without BSCs cover were selected. Soil biological properties such as microbial populations, soil respiration, microbial biomass carbon and nitrogen, as well as, other effective properties such asorganic carbon percent, total nitrogen, electrical conductivity, and available water content were measured in depths of 0-5 and 5-15 cm of soil with four replications. The gathered data were analyzed by nested plot, and the mean values were compared by Duncan test. Results and Discussion: The results showed that organic carbon and water content were higher at the surface under BSCs, followed by 5-15 cm soils under BSCs. Both soil depths of uncrusted soils showed substantially lower organic carbon and water content than the BSC-covered soils. Total nitrogen was far higher in BSC-encrusted surface

  9. Water use efficiency of six rangeland grasses under varied soil ...

    African Journals Online (AJOL)

    The changes in soil moisture content were measured by Gypsum Block which aided in determining the irrigation schedules. The grasses demonstrated varied levels of WUE which was evaluated by amount of biomass productivity in relation to evapotranspired water during the growing period. The three soil moisture content ...

  10. Power and limitation of soil properties as predictors of rangeland health and ecosystem functioning in a Northern mixed-grass prairie[Abstract

    Science.gov (United States)

    Soil properties are thought to affect rangeland ecosystem functioning (e.g. primary productivity, hydrology), and thus soil variables that are consistently correlated with key ecosystem functions may be general indicators of rangeland health. We summarize results from several studies in mixed-grass...

  11. New Tools to Estimate Runoff, Soil Erosion, and Sustainability of Rangeland Plant Communities

    Science.gov (United States)

    Rangelands are the largest land cover type in the world. Degradation from mismanagement, desertification, and drought impact more than 50% of rangelands across the globe. The USDA Agricultural Research Service has been evaluating sustainability of rangeland for over 40-years by conducted rangeland r...

  12. Modelling the effect of soil moisture and organic matter degradation on biogenic NO emissions from soils in Sahel rangeland (Mali

    Directory of Open Access Journals (Sweden)

    C. Delon

    2015-06-01

    Full Text Available This work is an attempt to provide seasonal variation of biogenic NO emission fluxes in a Sahelian rangeland in Mali (Agoufou, 15.34° N, 1.48° W for years 2004, 2005, 2006, 2007 and 2008. Indeed, NO is one of the most important precursors for tropospheric ozone, and previous studies have shown that arid areas potentially display significant NO emissions (due to both biotic and abiotic processes. Previous campaigns in the Sahel suggest that the contribution of this region in emitting NO is no longer considered as negligible. However, very few data are available in this region, therefore this study focuses on model development. The link between NO production in the soil and NO release to the atmosphere is investigated in this modelling study, by taking into account vegetation litter production and degradation, microbial processes in the soil, emission fluxes, and environmental variables influencing these processes, using a coupled vegetation–litter decomposition–emission model. This model includes the Sahelian Transpiration Evaporation and Productivity (STEP model for the simulation of herbaceous, tree leaf and faecal masses, the GENDEC model (GENeral DEComposition for the simulation of the buried litter decomposition and microbial dynamics, and the NO emission model (NOFlux for the simulation of the NO release to the atmosphere. Physical parameters (soil moisture and temperature, wind speed, sand percentage which affect substrate diffusion and oxygen supply in the soil and influence the microbial activity, and biogeochemical parameters (pH and fertilization rate related to N content are necessary to simulate the NO flux. The reliability of the simulated parameters is checked, in order to assess the robustness of the simulated NO flux. Simulated yearly average of NO flux ranges from 2.09 to 3.04 ng(N m−2 s−1 (0.66 to 0.96 kg(N ha−1 yr−1, and wet season average ranges from 3.36 to 5.48 ng(N m−2 s−1 (1.06 to 1.73 kg(N ha−1 yr−1

  13. Rangeland degradation in savannas of South Africa: spatial patterns of soil and vegetation

    Science.gov (United States)

    Sandhage-Hofmann, Alexandra; Löffler, Jörg; du Preez, Chris; Kotzé, Elmarie; Weijers, Stef; Wundram, Dirk; Zacharias, Maximilan; Amelung, Wulf

    2017-04-01

    Extensive bush encroachment by Acacia mellifera and associated woody species at semi-arid and arid sites are the most notable forms of rangeland degradation in savannas of South Africa. Concerns are growing over the threat of suppression and loss of nutritious perennial grass species. Grazing and different rangeland management systems (communal and freehold) are considered to be of major importance for degradation, but the process of encroachment is not restricted to communal land. A vegetation change is mostly accompanied by changes in soil properties, where soils in savanna systems can profit from woody species due to litter fall, root distribution, shadow and animal resting time. Savannas are very heterogeneous systems with high spatial variation of patches with wood, herbaceous species and bare ground. We hypothesized that the spatial patterns of soil properties in South Africás rangelands are controlled by present or past vegetation, modulated by the tenure systems with higher rangeland degradation in communal areas. To test this, we sampled soils at communal and commercial land in the Kuruman area of South Africa with the following design: three farms per tenure system, 6 randomly chosen plots (100x100m) per farm, and 25 soil samples (0-10 cm) per plot, each in a 5x5m sampling area. At every sampling point, information of overlying vegetation was recorded (species or bare soil, canopy size, height). For each sampling area, if present, trees/ shrubs were sampled and their ages estimated through the counting of annual growth rings. For each plot, high resolution UAV aerial photos were taken to evaluate the extent of bush encroachment. Analyses involved main physical and chemical soil parameters and isotopic analyses. The results of a rough aerial image classification (grass, woody species, bare ground) revealed significant differences between the tenure systems with higher coverage of bare ground and shrubs at communal farms, and higher grass cover at

  14. Feeding goats on scrubby Mexican rangeland and pasteurization: influences on milk and artisan cheese quality.

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    Hilario, Mario Cuchillo; Puga, Claudia Delgadillo; Wrage, Nicole; Pérez-Gil R, Fernando

    2010-08-01

    The objective of this study was to evaluate the effect of foraging on local scrubby rangeland versus stable feeding with high-protein concentrate as well as the compulsory pasteurization process on goats' milk and artisan soft cheese quality in terms of chemical composition and fatty acid profile. The results indicated that there were no significant differences in the energy, fat, or ash content of milk and cheese due to feeding; however, a significant influence of feeding on cheese protein and fatty acids in both milk and cheese was detected. Feeding on scrubby rangeland tended to increase the amounts of major polyunsaturated fatty acids in milk and cheese from goats. Pasteurization, which is mandatory in Mexico, did not alter the fatty acid concentrations in milk or cheese. Small goat-keepers using rangeland resources might claim better economical returns for products recognized as healthier. Further investigations to assure ecosystem sustainability of shrubby rangeland joined with economical evaluations and best animal management to avoid deleterious effects are recommended.

  15. Advances in Predicting Soil Erosion After Fire Using the Rangeland Hydrology and Erosion Model

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    Al-Hamdan, Osama Z.; Pierson, Frederick B.; Nearing, Mark A.; Williams, C. Jason; Hernandez, Mariano; Boll, Jan; Nouwakpo, Sayjro; Weltz, Mark A.; Spaeth, Kenneth E.

    2017-04-01

    The magnitude of erosion from a hillslope is governed by the availability of sediment and connectivity of overland flow and erosion processes. For undisturbed conditions, sediment is mainly detached and transported by rainsplash and sheetflow (splash-sheet) processes in bare batches, but sediment generally only travels a short distance before deposition. On recently disturbed sites (e.g., after fire), bare ground is more extensive and runoff and erosion rates are higher relative to undisturbed conditions. Increased erosion following disturbance occurs largely due to a shift from splash-sheet to concentrated-flow-dominated processes. On long-disturbed sites (e.g., after woody plant encroachment), years of soil loss can limit sediment availability and soil erosion. In contrast, recently burned landscapes typically have ample sediment available and generate high erosion rates. This presentation highlights recent advancements in hillslope erosion prediction by the Rangeland Hydrology and Erosion Model (RHEM) that accommodate recently burned conditions. The RHEM tool is a process-based model that was developed specifically for predicting hillslope runoff and erosion on rangeland ecosystems. The advancements presented here include development of empirical equations to predict erodibility parameters for conditions in which erosion by concentrated flow processes is limited (by runoff or sediment availability) and an erodibility parameter for conditions in which erosion by concentrated flow processes is the dominant erosion mechanism and sediment is amply available (burned conditions). The data used for developing and evaluating the erodibility parameter equations were obtained from rainfall simulation databases maintained by the USDA-Agricultural Research Service. The data span undisturbed, long-disturbed, and recently burned conditions. For undisturbed and long-disturbed conditions, a regression analysis was applied to derive the relationship between splash

  16. Historical soil erosion rates in rangelands of SW Spain determined using botanical evidences and high resolution 3D data

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    Schnabel, Susanne; Rubio-Delgado, Judit; Gómez-Gutiérrez, Álvaro

    2014-05-01

    The estimation of medium-term sheet erosion rates represents still a challenge in areas with long land use history. In the present paper, a new methodology for estimating medium-term sheet erosion rates is presented and applied in a wooded rangeland (dehesa). This human-induced semi-natural ecosystem is widespread in SW Iberian Peninsula and is characterized by centuries of agrosilvopastoral land use, being livestock breeding the most important economic activity at present. Vast areas are covered by shallow and poor soils, pointing to a long history of soil erosion. Research carried out in a representative area with open plots revealed low soil loss rates and degradation studies showed high spatial variation related with land use intensity. Knowledge on past soil erosion rates and its relation with land use is necessary in order to understand present soil properties and also for giving adequate advice on land management. The present paper presents results of a pilot study on historical soil erosion in Mediterranean wooded rangelands. The methodology is based on the analysis of the morphology of tree stems, exposed roots and surface micro-topography using data obtained with a Terrestrial Laser Scanner. Specifically, botanical evidences were used to estimate the antecedent level of the soil surface. Afterwards, previous and current surfaces were confronted in order to obtain a volume of soil loss in the area influenced by the tree canopy, as well as for the open spaces. On the other hand, the age of the trees in the study area was estimated by means of an existing tree growth model. Finally, soil erosion rates were calculated using the volume of soil loss and the estimated age of every tree. The sampling was carried out in a farm in the Spanish province of Cáceres, with a two-layered vegetation, of grasses and scattered trees (Quercus ilex). Climate is Mediterranean with mean annual temperature of 160C and an annual rainfall of 620 mm. Soils are very shallow

  17. IMPACT OF WOODY PLANTS SPECIES ON SOIL PHYSIO-CHEMICAL PROPERTIES ALONG GRAZING GRADIENTS IN RANGELANDS OF EASTERN ETHIOPIA

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    Mohammed Mussa Abdulahi

    2016-12-01

    Full Text Available In the lowlands of arid and semiarid rangelands woody plants plays an important role in soil fertility maintenance, providing food, medicine, cosmetics, fodder, fuel wood and pesticides. A better understanding of the interaction of woody plants on their immediate environment is needed to guide optimum management of native vegetation in the production landscapes. However, the impact of woody plant species on soil properties remains poorly understood. This study evaluates the impact of two dominant woody plant species (A. senegal and B. aegyptica on soil physico-chemical properties along grazing gradients in rangelands of eastern Ethiopia. Six trees of each species were selected from light, moderate and heavy grazing sites.  Soil sample data at two depths (0-15 and 16-30 cm were collected from under and open areas of A. senegal and B. aegyptica from each grazing sites, and analysed for nutrient contents. The nutrient status of soil under both woody species was significantly higher especially with regard to soil organic matter (4.37%, total nitrogen (0.313%, and available phosphorus (11.62 than the open grassland with soil organic matter (3.82%, total nitrogen (0.246%, and available phosphorus (10.94 mg/Kg soil for A. Senegal. The soil organic matter (3.93%, total nitrogen (0.285%, available phosphorus (11.66 mg/Kg soil were significantly higher than open grassland with soil organic matter (3.52%, total nitrogen (0.218%, available phosphorus (10.73 mg/Kg soil for B. aegyptica. This was more pronounced in the top 15 cm of soil under A. senegal woody plant species and on the light and moderate grazing site. Therefore, this tree has a significant effect on soil fertility improvement in resource poor rangelands and as a result, it is important to retain scattered A. senegal and B. aegyptica plants in the lowlands of eastern Ethiopia.

  18. Soils as a Solution: The Potential of Rangelands to Contribute to Climate Change Mitigation

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    Silver, W. L.; Ryals, R.; DeLonge, M. S.; Owen, J. J.

    2015-12-01

    The majority of soil-related climate change research has focused on describing the problem - estimating rates of carbon (C) losses and greenhouse gas (GHG) emissions from natural and managed ecosystems. More research is needed to explore potential solutions to climate change through mitigation and adaptation. Here we report on an integrated set of studies aimed at critically evaluating the biogeochemical potential of rangeland soils to help mitigate climate change, while improving the sustainability and productivity of food production systems. We explored direct effects through enhanced net primary production (NPP) and soil C sequestration, and indirect effects through diversion of high emitting sources to lower emitting organic matter dynamics. We used a combination of long- and short-term field experiments, modeling, laboratory assays, life cycle assessment (LCA), and meta-analyses in consultation with a diverse group of stakeholders from both the private and public sectors. We found that organic matter amendments held particularly strong potential. Compost amendments increased soil C storage by 0.5-1.0 Mg C ha-1 y-1 in surface soils over 5 y, and increased NPP and water holding capacity. We measured 1.0 Mg of new C ha-1 y-1 over 3 y. Long-term amendment of cattle manure increased surface soil C by 19.0±7.3 Mg C ha-1 relative to unmanured fields. However, field and modeling experiments suggested that manure amendments lead to large nitrous oxide emissions that eventually eliminated CO2e benefits, whereas compost amendments continued to benefit climate for decades longer. An LCA identified a broader range of climate impacts. When scaled to an area of 25% of California's rangelands, new C sequestered following compost amendments (21 million Mg CO2e) exceeded emissions from cattle (15 million Mg CO2e); diverting organics from waste streams to amendments led to additional GHG savings. In collaboration with our partners, our research contributed to the development of

  19. Effects of land use change and management on SOC and soil quality in Mediterranean rangelands areas

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    Parras-Alcántara, Luis; Lozano-García, Beatriz; Requejo, Ana; Zornoza, Raúl

    2017-04-01

    INTRODUCTION Rangelands in the Iberian Peninsula occupy more than 90,000 km2. These rangelands were created from the former Mediterranean oak forests, mainly composed of holm oak and cork oak (Quercus ilex rotundifolia and Quercus suber), by clear-cutting shrubs, removing selected trees and cultivating. These man-made landscapes are called 'dehesas' in Spain and 'montados' in Portugal. Between 1955 and 1981, more than 5,000 km2 of dehesas was converted from pastureland to cultivated land. This process has been accelerated since 1986 owing to subsidies from the European Common Agricultural Policy (Parras-Alcántara et al., 2015a). The role that natural rangelands play in the global carbon cycle is extremely important, accounting for 10-30% of the world's total soil organic carbon (SOC), in addition, SOC concentration is closely related to soil quality and vegetation productivity (Brevik, 2012). Therefore, to study the land use and management changes is important, particularly in Mediterranean soils, as they are characterized by low organic carbon content, furthermore, the continuous use of ploughing for grain production is the principal cause of soil degradation. Therefore, land use decisions and management systems can increase or decrease SOC content and stock (Corral-Fernández et al., 2013; Parras-Alcántara et al., 2014, 2015a and 2015b; Parras-Alcántara and Lozano-García, 2014) MATERIAL AND METHODS A field study was conducted to determine the land use change (Mediterranean evergreen oak woodland to olive grove and cereal, all of them managed under conventional tillage and under conservationist practices) effects on SOC stocks and the soil quality (Stratification Ratio) in Los Pedroches valley, southern Spain. RESULTS Results for the present study indicate that management practices had little effect on SOC storage in dehesas. The stratification ratio was >2 both under conventional tillage and under organic farming, so, soils under dehesa had high quality

  20. Soil compaction related to grazing and its effects on herbaceous roots frequency and soil organic matter content in rangelands of SW Spain

    Science.gov (United States)

    Pulido, Manuel; Schnabel, Susanne; Francisco Lavado Contador, Joaquín; Miralles Mellado, Isabel

    2016-04-01

    Rangelands in SW Spain occupy a total surface area of approximately 6 million ha and constitute the most representative extensive ranching system of the Iberian Peninsula gathering more than 13 million livestock heads. They are characterised by an herbaceous layer, mostly composed of therophytic species, with a disperse tree cover, mainly holm oak and cork oak (Quercus ilex rotundifolia and Q. suber), interspersed with shrubs in many places. This type of land system is of ancient origin and experienced frequent changes in land use in the past, since agricultural, livestock and forestry activities have coexisted within the same farms. In recent decades, livestock farming has become dominant due, in part, to the subsidies of the Common Agriculture Policy. Since Spain joined the European Union in 1986 until the year 2000, the number of domestic animals doubled, particularly cattle, and consequently animal stocking rates have increased on average from 0.40 AU ha-1 up to 0.70 AU ha-1. This increase in animal stocking rates, along with a progressive substitution of cattle instead of sheep in many farms, has led to the occurrence of land degradation processes such as the reduction of grass cover or soil compaction in heavily grazed areas. Previous research has evidenced higher values of soil bulk density and resistance to penetration as well as larger bare surface areas in spring in fenced areas with animal stocking rates above 1 AU ha-1. However, a better understanding of how increasing bulk density or resistance to penetration influence the frequency of herbaceous roots and how a reduction in the frequency of roots affects soil organic matter content in rangelands is still unknown. Therefore, the main goal of this study was to determine possible relationships between the frequencies of herbaceous roots and soil organic matter content in order to understand the effect of excessive animal numbers on the depletion of soil fertility by reducing progressively the quantity of

  1. RANGELAND SEQUESTRATION POTENTIAL ASSESSMENT

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    Lee Spangler; George F. Vance; Gerald E. Schuman; Justin D. Derner

    2012-03-31

    Rangelands occupy approximately half of the world's land area and store greater than 10% of the terrestrial biomass carbon and up to 30% of the global soil organic carbon. Although soil carbon sequestration rates are generally low on rangelands in comparison to croplands, increases in terrestrial carbon in rangelands resulting from management can account for significant carbon sequestration given the magnitude of this land resource. Despite the significance rangelands can play in carbon sequestration, our understanding remains limited. Researchers conducted a literature review to identify sustainably management practices that conserve existing rangeland carbon pools, as well as increase or restore carbon sequestration potentials for this type of ecosystem. The research team also reviewed the impact of grazing management on rangeland carbon dynamics, which are not well understood due to heterogeneity in grassland types. The literature review on the impact of grazing showed a wide variation of results, ranging from positive to negative to no response. On further review, the intensity of grazing appears to be a major factor in controlling rangeland soil organic carbon dynamics. In 2003, researchers conducted field sampling to assess the effect of several drought years during the period 1993-2002. Results suggested that drought can significantly impact rangeland soil organic carbon (SOC) levels, and therefore, carbon sequestration. Resampling was conducted in 2006; results again suggested that climatic conditions may have overridden management effects on SOC due to the ecological lag of the severe drought of 2002. Analysis of grazing practices during this research effort suggested that there are beneficial effects of light grazing compared to heavy grazing and non-grazing with respect to increased SOC and nitrogen contents. In general, carbon storage in rangelands also increases with increased precipitation, although researchers identified threshold levels of

  2. Soil organic carbon erosion and its subsequent fate in the Karoo rangeland

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    Krenz, Juliane; Greenwood, Philip; Kuhn, Brigitte; Heckrath, Goswin; Foster, Ian; Boardman, John; Meadows, Michael; Kuhn, Nikolaus

    2016-04-01

    The rangelands of the Great Karoo region in South Africa have experienced a number of environmental changes. With the settling of European farmers in the second half of the 18th century, agricultural activities increased, leading to overgrazing and probably representing a trigger to land degradation. Ongoing land-use change and shifting rainfall patterns resulted in the development of badlands on foot slopes of upland areas, and complex gully systems in valley bottoms. Many dams and small reservoirs have been constructed to provide drinking water for cattle or to facilitate irrigation during dry periods, as a consequence of agricultural intensification. Most of the dams soon in-filled with sediment and many were eventually breached. Such a process offers the potential to use these breached dams as an environmental archive to analyse land use changes as well as carbon (C) erosion and deposition during the last ca. 100 years. In this ongoing project, a combination of analytical methods that include drone imagery, landscape mapping and sediment analysis have been employed to determine whether land degradation in the Karoo has resulted in the reversion from a net sink of C to a net source of C. Firstly, drone imagery will be used to produce a high-resolution digital elevation model for areas especially prone to erosion and for determining the volume calculation of eroded sediment in the catchment area. Secondly, sediment deposits from the same silted-up reservoir were analysed for varying physicochemical parameters, in order to analyse and reconstruct erosional and depositional patterns. Total Carbon (TC) content was recorded and the sharp decrease in total C content with decreasing depth suggests that land degradation during and after post-European settlement probably led to accelerated erosion of the then relatively fertile surface soils. This presumably resulted in the rapid in-filling of reservoirs with carbon-rich surface material which is found at the base of

  3. Evaluating the influence of physical, economic and managerial factors on sheet erosion in rangelands of SW Spain by performing a sensitivity analysis on an integrated dynamic model.

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    Ibáñez, J; Lavado Contador, J F; Schnabel, S; Martínez Valderrama, J

    2016-02-15

    An integrated dynamic model was used to evaluate the influence of climatic, soil, pastoral, economic and managerial factors on sheet erosion in rangelands of SW Spain (dehesas). This was achieved by means of a variance-based sensitivity analysis. Topsoil erodibility, climate change and a combined factor related to soil water storage capacity and the pasture production function were the factors which influenced water erosion the most. Of them, climate change is the main source of uncertainty, though in this study it caused a reduction in the mean and the variance of long-term erosion rates. The economic and managerial factors showed scant influence on soil erosion, meaning that it is unlikely to find such influence in the study area for the time being. This is because the low profitability of the livestock business maintains stocking rates at low levels. However, the potential impact of livestock, through which economic and managerial factors affect soil erosion, proved to be greater in absolute value than the impact of climate change. Therefore, if changes in some economic or managerial factors led to higher stocking rates in the future, significant increases in erosion rates would be expected. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Rangeland Hydrology and Erosion Model

    Science.gov (United States)

    Nearing, Mark; Pierson, Fred; Hernandez, Mariano; Al-Hamdan, Osama; Weltz, Mark; Spaeth, Ken; Wei, Haiyan; Stone, Jeff

    2013-04-01

    Soil loss rates on rangelands are considered one of the few quantitative indicators for assessing rangeland health and conservation practice effectiveness. An erosion model to predict soil loss specific for rangeland applications has been needed for many years. Most erosion models were developed from croplands where the hydrologic and erosion processes are different, largely due to much higher levels of heterogeneity in soil and plant properties at the plot scale and the consolidated nature of the soils. The Rangeland Hydrology and Erosion Model (RHEM) was designed to fill that need. RHEM is an event-based model that estimates runoff, erosion, and sediment delivery rates and volumes at the spatial scale of the hillslope and the temporal scale of a single rainfall event. It represents erosion processes under normal and fire-impacted rangeland conditions, it adopts a new splash erosion and thin sheet-flow transport equation developed from rangeland data, and it links the model hydrologic and erosion parameters with rangeland plant communities by providing a new system of parameter estimation equations based on 204 plots at 49 rangeland sites distributed across 15 western U.S. states. Recent work on the model is focused on representing intra-storm dynamics, using stream-power as the driver for detachment by flow, and deriving parameters for after-fire conditions.

  5. Ecological site-based assessments of wind and water erosion: informing accelerated soil erosion management in rangelands

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    Webb, Nicholas P.; Herrick, Jeffrey E.; Duniway, Michael C.

    2014-01-01

    Accelerated soil erosion occurs when anthropogenic processes modify soil, vegetation or climatic conditions causing erosion rates at a location to exceed their natural variability. Identifying where and when accelerated erosion occurs is a critical first step toward its effective management. Here we explore how erosion assessments structured in the context of ecological sites (a land classification based on soils, landscape setting and ecological potential) and their vegetation states (plant assemblages that may change due to management) can inform systems for reducing accelerated soil erosion in rangelands. We evaluated aeolian horizontal sediment flux and fluvial sediment erosion rates for five ecological sites in southern New Mexico, USA, using monitoring data and rangeland-specific wind and water erosion models. Across the ecological sites, plots in shrub-encroached and shrub-dominated vegetation states were consistently susceptible to aeolian sediment flux and fluvial sediment erosion. Both processes were found to be highly variable for grassland and grass-succulent states across the ecological sites at the plot scale (0.25 Ha). We identify vegetation thresholds that define cover levels below which rapid (exponential) increases in aeolian sediment flux and fluvial sediment erosion occur across the ecological sites and vegetation states. Aeolian sediment flux and fluvial erosion in the study area can be effectively controlled when bare ground cover is 100 cm in length is less than ~35%. Land use and management activities that alter cover levels such that they cross thresholds, and/or drive vegetation state changes, may increase the susceptibility of areas to erosion. Land use impacts that are constrained within the range of natural variability should not result in accelerated soil erosion. Evaluating land condition against the erosion thresholds identified here will enable identification of areas susceptible to accelerated soil erosion and the development of

  6. Ecological site‐based assessments of wind and water erosion: informing accelerated soil erosion management in rangelands.

    Science.gov (United States)

    Webb, Nicholas P; Herrick, Jeffrey E; Duniway, Michael C

    Accelerated soil erosion occurs when anthropogenic processes modify soil, vegetation, or climatic conditions causing erosion rates at a location to exceed their natural variability. Identifying where and when accelerated erosion occurs is a critical first step toward its effective management. Here we explored how erosion assessments structured in the context of ecological sites (a land classification based on soils, landscape setting, and ecological potential) and their vegetation states (plant assemblages that may change due to management) can inform systems for reducing accelerated soil erosion in rangelands. We evaluated aeolian horizontal sediment flux and fluvial sediment erosion rates for five ecological sites in southern New Mexico, USA, using monitoring data and rangeland-specific wind and water erosion models. Across the ecological sites, plots in shrub-encroached and shrub-dominated vegetation states were consistently susceptible to aeolian sediment flux and fluvial sediment erosion. Both processes were found to be highly variable for grassland and grass–succulent states across the ecological sites at the plot scale (0.25 ha). We identified vegetation thresholds that define cover levels below which rapid (exponential) increases in aeolian sediment flux and fluvial sediment erosion occur across the ecological sites and vegetation states. Aeolian sediment flux and fluvial erosion in the study area could be effectively controlled when bare ground cover was 100 cm in length was less than ∼35%. Land use and management activities that alter cover levels such that they cross thresholds, and/or drive vegetation state changes, may increase the susceptibility of areas to erosion. Land use impacts that are constrained within the range of natural variability should not result in accelerated soil erosion. Evaluating land condition against the erosion thresholds identified here will enable identification of areas susceptible to accelerated soil erosion and the

  7. Pastoralism, land degradation and Carbon redistribution in rangelands

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    Kuhn, Nikolaus J.; Ali, Seid Mohammed

    2017-04-01

    Pastoralism is rarely viewed as a major future form of land use, because of well-documented cases of rangeland degradation, attributed to irrational overstocking, and the subsequent losses of ecosystem services. However, pastoralists were actually encouraged to settle and adopt such strategies, copied from rangelands with higher and more reliable rainfall. This curtailed mobility resulted in a shift from opportunistic and extensive land use to more intensive and settled forms of use, and promoted degradation of vegetation and soils and the ecosystem services they provided. However, pastoralists traditionally employed several techniques to manage rangeland resources. These practices, such as the use of seasonal grassland reserves and livestock mobility, influence vegetation composition, coverage and abundance in rangelands and preserved ecosystem services relevant for pastoralists. The traditional practices also offer tools for soil and vegetation protection and restoration, thereby contributing to the mitigation of climate change. However, various internal and external factors have curtailed traditional management practices and livestock mobility, breaking the co-evolved balance of vegetation, wildlife and land use, thus exposing rangeland to continued livestock pressure, which often leads to degradation. Rather than abandoning pastoralism as consequence of 20th century land degradation, the revitalisation of traditional practices and indigenous knowledge can be vital to secure sustainable livelihoods for millions of pastoralists and to maintain rangeland ecosystem services.

  8. Analysis of Vegetation Phytosociological Characteristics and Soil Physico-Chemical Conditions in Harishin Rangelands of Eastern Ethiopia

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    Haftay Hailu

    2017-01-01

    Full Text Available The objective of this study is to analyse the phytodiversity, distribution, herb biomass and physico-chemical conditions of the vegetation system in the context of communal continuous open grazing and enclosed grazing management practices in the Harishin rangelands of Eastern Ethiopia. A total of 58 herbaceous species and 11 woody species were recorded in the study area. Analysis of Importance Value Index for two management practices was represented by different combinations of species with varied dominance. The herbs’ diversity–dominance curve revealed a lognormal distribution in both managements practices. The overview of distribution patterns for most of the species layer showed contiguous growth and a clumped distribution pattern. Species diversity, richness, herb biomass, basal cover and soil physico-chemical attributes showed a distinct separation in relation to grazing management practices. Based on the findings, one can conclude that the establishment of enclosures has a positive impact in restoring rangeland vegetation diversity, distribution, in increasing herb productivity and in boosting soil fertility.

  9. Digital soil mapping using remote sensing indices, terrain attributes, and vegetation features in the rangelands of northeastern Iran.

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    Mahmoudabadi, Ebrahim; Karimi, Alireza; Haghnia, Gholam Hosain; Sepehr, Adel

    2017-09-11

    Digital soil mapping has been introduced as a viable alternative to the traditional mapping methods due to being fast and cost-effective. The objective of the present study was to investigate the capability of the vegetation features and spectral indices as auxiliary variables in digital soil mapping models to predict soil properties. A region with an area of 1225 ha located in Bajgiran rangelands, Khorasan Razavi province, northeastern Iran, was chosen. A total of 137 sampling sites, each containing 3-5 plots with 10-m interval distance along a transect established based on randomized-systematic method, were investigated. In each plot, plant species names and numbers as well as vegetation cover percentage (VCP) were recorded, and finally one composite soil sample was taken from each transect at each site (137 soil samples in total). Terrain attributes were derived from a digital elevation model, different bands and spectral indices were obtained from the Landsat7 ETM+ images, and vegetation features were calculated in the plots, all of which were used as auxiliary variables to predict soil properties using artificial neural network, gene expression programming, and multivariate linear regression models. According to R 2 RMSE and MBE values, artificial neutral network was obtained as the most accurate soil properties prediction function used in scorpan model. Vegetation features and indices were more effective than remotely sensed data and terrain attributes in predicting soil properties including calcium carbonate equivalent, clay, bulk density, total nitrogen, carbon, sand, silt, and saturated moisture capacity. It was also shown that vegetation indices including NDVI, SAVI, MSAVI, SARVI, RDVI, and DVI were more effective in estimating the majority of soil properties compared to separate bands and even some soil spectral indices.

  10. Fire impact on soil-water repellency and functioning of semi-arid croplands and rangelands: Implications for prescribed burnings and wildfires

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    Stavi, Ilan; Barkai, Daniel; Knoll, Yaakov M.; Glion, Hiam Abu; Katra, Itzhak; Brook, Anna; Zaady, Eli

    2017-03-01

    An unintended fire outbreak during summer 2015 in the semi-arid Israeli Negev resulted in the burning of extensive croplands and rangelands. The rangelands have been managed over the long term for occasional grazing, while the croplands have been utilized for rainfed wheat cropping. Yet, during the studied year, the croplands were left fallow, allowing the growth of herbaceous vegetation, which was harvested and baled for hay before the fire outbreak. The study objectives were to investigate the impacts of fire, land-use, and soil depth on water-repellency and on the status and dynamics of some of the most important organic and mineral soil resources. Additionally, we aimed to assess the severity of this fire outbreak. The soil-water repellency was studied by measuring the soil's water drop penetration time (WDPT) and critical surface tension (CST). A significant effect of fire on soil hydrophobicity was recorded, with a slight increase in mean WDPT and a slight decrease in mean CST in the burnt sites than in the non-burnt sites. Yet, soil hydrophobicity in the burnt lands was rather moderate and remained within the water repellency's lowest class. A significant effect of land-use on the means of WDPT and CST was also recorded, being eleven-fold greater and 7% smaller, respectively, in the rangelands than in the croplands. This is consistent with the almost eightfold greater mean above-ground biomass recorded in the non-burnt rangelands than in the non-burnt post-harvest croplands, revealing the positive relations between available fuel load and soil-water repellency. The effect of soil depth was significant for CST but not for WDPT. Overall, the gathered data suggest that fire severity was low to moderate. Fire was also found to significantly affect the organic carbon and ammonium-N were also studied, and generally showed higher values for the burnt lands. Overall, this study shows that the low- to moderate-fire severity only slightly increased the soil water

  11. RANGELAND DEGRADATION: EXTENT, IMPACTS, AND ALTERNATIVE RESTORATION TECHNIQUES IN THE RANGELANDS OF ETHIOPIA

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    Mohammed Mussa Abdulahi

    2016-12-01

    Full Text Available Rangeland degradation remains a serious impediment to improve pastoral livelihoods in the lowlands of Ethiopia. This review paper presents an overview of the extent of rangeland degradation, explores its drivers, discusses the potential impacts of rangeland degradation and also suggests alternative rangeland restoration techniques. It is intended to serve as an exploratory tool for ensuing more detailed quantitative analyses to support policy and investment programs to address rangeland degradation in Ethiopia. The extent of rangeland degradation increases with time, and the productivity of rangelands are losing if not given due attention. The major drivers leading to rangeland degradation includes climate change, overgrazing, bush encroachment, population pressure, drought, and government policy, encroachment of rain fed agriculture and decline of traditional resource management institution. Degradation of rangeland has resulted in substantial declines in rangeland condition, water potential, soil status, and animal performance, livestock holding at the household level and community become destitute. Another consequence of rangeland degradation is linked to food insecurity, poverty to the extent of food aid, expansion of aridity and the need for alternative livelihood and income diversification. Moreover, it has increasingly become a threat to the pastoral production systems, and has contributed towards increases in poverty and tribal conflicts over grazing land and water resources. In spite of these impacts, the adoption of alternative restoration techniques in the country is highly insufficient. To address rangeland degradation problems, there is a strong need to substantially increase the investments and strengthen the policy support for sustainable land management.

  12. Scale effects on runoff and soil erosion in rangelands: observations and estimations with predictors of different availability

    Science.gov (United States)

    Runoff and erosion estimates are needed for rangeland management decisions and evaluation of ecosystem services derived from rangeland conservation practices. The information on the effect of scale on the runoff and erosion, and on the choice of runoff and erosion predictors, remains scarce. The obj...

  13. Remote sensing applications for monitoring rangeland vegetation ...

    African Journals Online (AJOL)

    Remote sensing techniques hold considerable promise for the inventory and monitoring of natural resources on rangelands. A significant lack of information concerning basic spectral characteristics of range vegetation and soils has resulted in a lack of rangeland applications. The parameters of interest for range condition ...

  14. A review of concentrated flow erosion processes on rangelands: Fundamental understanding and knowledge gaps

    Directory of Open Access Journals (Sweden)

    Sayjro K. Nouwakpo

    2016-06-01

    Full Text Available Concentrated flow erosion processes are distinguished from splash and sheetflow processes in their enhanced ability to mobilize and transport large amounts of soil, water and dissolved elements. On rangelands, soil, nutrients and water are scarce and only narrow margins of resource losses are tolerable before crossing the sustainability threshold. In these ecosystems, concentrated flow processes are perceived as indicators of degradation and often warrant the implementation of mitigation strategies. Nevertheless, this negative perception of concentrated flow processes may conflict with the need to improve understanding of the role of these transport vessels in redistributing water, soil and nutrients along the rangeland hillslope. Vegetation influences the development and erosion of concentrated flowpaths and has been the primary factor used to control and mitigate erosion on rangelands. At the ecohydrologic level, vegetation and concentrated flow pathways are engaged in a feedback relationship, the understanding of which might help improve rangeland management and restoration strategies. In this paper, we review published literature on experimental and conceptual research pertaining to concentrated flow processes on rangelands to: (1 present the fundamental science underpinning concentrated flow erosion modeling in these landscapes, (2 discuss the influence of vegetation on these erosion processes, (3 evaluate the contribution of concentrated flow erosion to overall sediment budget and (4 identify knowledge gaps.

  15. Effects of Soil Management Practices on Water Erosion under Natural Rainfall Conditions on a Humic Dystrudept

    Directory of Open Access Journals (Sweden)

    Vinicius Ferreira Chaves de Souza

    Full Text Available ABSTRACT Water erosion is the main cause of soil degradation and is influenced by rainfall, soil, topography, land use, soil cover and management, and conservation practices. The objective of this study was to quantify water erosion in a Humic Dystrudept in two experiments. In experiment I, treatments consisted of different rates of fertilizer applied to the soil surface under no-tillage conditions. In experiment II, treatments consisted of a no-tillage in natural rangeland, burned natural rangeland and natural rangeland. Forage turnip, black beans, common vetch, and corn were used in rotation in the treatments with crops in the no-tillage during study period. The treatments with crops and the burned rangeland and natural rangeland were compared to a bare soil control, without cultivation and without fertilization. Increasing fertilization rates increased organic carbon content, soil resistance to disintegration, and the macropore volume of the soil, due to the increase in the dry mass of the crops, resulting in an important reduction in water erosion. The exponential model of the ŷ = ae-bx type satisfactorily described the reduction in water and soil losses in accordance with the increase in fertilization rate and also described the decrease in soil losses in accordance with the increase in dry mass of the crops. Water erosion occurred in the following increasing intensity: in natural rangeland, in cultivated natural rangeland, and in burned natural rangeland. Water erosion had less effect on water losses than on soil losses, regardless of the soil management practices.

  16. Vegetation restoration on degraded rangelands through the use of microcatchment and brush packs in the communal areas of the Eastern Cape

    CSIR Research Space (South Africa)

    Lesoli, MS

    2010-07-01

    Full Text Available Rangeland degradation results in declining functional capacity, increased poverty, and food insecurity. Major changes in rangeland surface morphology and soil characteristics have a drastic effect on the primary productivity of the rangeland...

  17. Effect of Grazing Intensity on Some Soil Chemical Characteristics in Gardaneh Zanburi Rangeland of Arsanjan

    Directory of Open Access Journals (Sweden)

    zeinab khademolhosseini

    2016-02-01

    Full Text Available Introduction:Changes caused by grazing on range ecosystem are generally assessed based on the soil conditions and vegetation. Livestock as one of the major elements in range land ecosystems has different effects on different parts of this ecosystem. One of these impacts is excessive livestock grazing capacity which can have different effects on soils and plants in various intensities. Materials and Methods:Gardaneh ZanbooriRangelandis located in Arsanjan in Fars province. This isanareaof mountains, hillsandplains with the maximum height of 2280 meters and minimum height of 1640 meters above sea level. Related areas were separated under three different management methods of enclosure, moderate grazing and heavy grazing. These three areas are considered as symbolic areas of grazing intensity including the reference area where no grazing intensity was observed, the key area where medium to heavy grazing was applied and critical area where heavy grazing was used. These areas were similar in all characteristics such as topography, soil type and rainfall and differed only in their grazing intensity factor. Then, soil samples were collected. Random systematic soil sampling was conducted at two horizons of 0 -15 and 15 -30 cm. Therefore, five profiles in each area (enclosure, moderate grazing and heavy grazing, a total of 15 soil profiles, were excavated and two samples were taken in each profile (one sample from each horizon. Finally, the thirty soil samples were transported to the laboratory. Samples were dried in the air laboratory and passed a two millimeter sieve after smashing. Factors such as N, P, K, OM, EC and PH were measured in each sample In the laboratory, the percentage of P was determined by the Olsen method while the percentage of K was determined using the flamephotometry method. Moreover, N was measured using the Kjeldhal method. C was measured by the Walkley and Black method. The percentage of OM was found by carbon multiplying

  18. High resolution mapping of soil organic carbon stocks using remote sensing variables in the semi-arid rangelands of eastern Australia.

    Science.gov (United States)

    Wang, Bin; Waters, Cathy; Orgill, Susan; Gray, Jonathan; Cowie, Annette; Clark, Anthony; Liu, De Li

    2018-02-23

    Efficient and effective modelling methods to assess soil organic carbon (SOC) stock are central in understanding the global carbon cycle and informing related land management decisions. However, mapping SOC stocks in semi-arid rangelands is challenging due to the lack of data and poor spatial coverage. The use of remote sensing data to provide an indirect measurement of SOC to inform digital soil mapping has the potential to provide more reliable and cost-effective estimates of SOC compared with field-based, direct measurement. Despite this potential, the role of remote sensing data in improving the knowledge of soil information in semi-arid rangelands has not been fully explored. This study firstly investigated the use of high spatial resolution satellite data (seasonal fractional cover data; SFC) together with elevation, lithology, climatic data and observed soil data to map the spatial distribution of SOC at two soil depths (0-5cm and 0-30cm) in semi-arid rangelands of eastern Australia. Overall, model performance statistics showed that random forest (RF) and boosted regression trees (BRT) models performed better than support vector machine (SVM). The models obtained moderate results with R 2 of 0.32 for SOC stock at 0-5cm and 0.44 at 0-30cm, RMSE of 3.51MgCha -1 at 0-5cm and 9.16MgCha -1 at 0-30cm without considering SFC covariates. In contrast, by including SFC, the model accuracy for predicting SOC stock improved by 7.4-12.7% at 0-5cm, and by 2.8-5.9% at 0-30cm, highlighting the importance of including SFC to enhance the performance of the three modelling techniques. Furthermore, our models produced a more accurate and higher resolution digital SOC stock map compared with other available mapping products for the region. The data and high-resolution maps from this study can be used for future soil carbon assessment and monitoring. Copyright © 2018 Elsevier B.V. All rights reserved.

  19. Analysis of Vegetation Phytosociological Characteristics and Soil Physico-Chemical Conditions in Harishin Rangelands of Eastern Ethiopia

    OpenAIRE

    Haftay Hailu

    2017-01-01

    The objective of this study is to analyse the phytodiversity, distribution, herb biomass and physico-chemical conditions of the vegetation system in the context of communal continuous open grazing and enclosed grazing management practices in the Harishin rangelands of Eastern Ethiopia. A total of 58 herbaceous species and 11 woody species were recorded in the study area. Analysis of Importance Value Index for two management practices was represented by different combinations of species with v...

  20. Influence of forest and rangeland management on anadromous fish habitat in Western North America: impacts of natural events.

    Science.gov (United States)

    Douglas N. Swanston

    1980-01-01

    Natural events affecting vegetative cover and the hydrology and stability of a stream and its parent watershed are key factors influencing the quality of anadromous fish habitat. High intensity storms, drought, soil mass movement, and fire have the greatest impacts. Wind, stream icing, and the influence of insects and disease are important locally...

  1. Effects of feral free-roaming horses on semi-arid rangeland ecosystems: an example from the sagebrush steppe

    Science.gov (United States)

    Feral horses (Equus caballus) are viewed as a symbol of freedom and power; however, they are also a largely unmanaged, non-native grazer in North America, South America, and Australia. Information on their influence on vegetation and soil characteristics in semi-arid rangelands has been limited by ...

  2. A collaborative characterization of North American grasslands and rangelands: climate, ecohydrology and carbon sink-source dynamics

    Science.gov (United States)

    Petrie, M. D.; Brunsell, N. A.; Vargas, R.; Collins, S. L.

    2013-12-01

    Grassland and rangeland ecoregions extend across the North American continent and exhibit diversity in climate, ecosystem services, and biophysical processes. In many grasslands and rangelands, the potential for reductions in ecosystem services and for large-scale ecosystem state change may increase under future climate scenarios. Climate change projections for North America vary, however, and the way changing climate will influence specific ecoregions is largely unknown. To better understand the regional effects of climate change on grasslands and rangelands, it is important to better understand the biophysical characteristics of these systems locally, and to identify the sensitivity of these characteristics to observed climate variation. In our study, we propose to use eddy covariance, soil moisture and precipitation data to identify how the grasslands and rangelands of North America differ in their responses to climate variability through time, with specific focus on the active growing season. Our primary goal is to determine the sensitivity of ecosystem Net Primary Productivity [NPP] to variation in temperature and precipitation patterns, and classify North American grasslands and rangelands by these sensitivities in addition to more standard climate and productivity variables. Our preliminary analyses in mesic, semiarid and arid grasslands in Kansas, Colorado and New Mexico show significant (P photosynthesis in spring and of senescense in the fall, grassland and rangeland ecosystems in Kansas (top and bottom left panels) and New Mexico (bottom right panel) display differing patterns of activity throughout the year.

  3. Symbiotic fungi that influence vigor, biomass and reproductive potential of native bunch grasses for remediation of degraded semiarid rangelands

    Science.gov (United States)

    Jerry R. Barrow; Mary E. Lucero; Isaac Reyes-Vera

    2008-01-01

    A steady decline of perennial bunch grasses in arid rangelands has resulted in losses of productivity and germplasm. Remediation is costly and rarely successful. Cryptic symbiotic fungi, structurally integrated with cells and organs of native plants cannot be separated from host plant tissue. However, they were successfully transferred from cell cultures of native...

  4. In-filled reservoirs serving as sediment archives to analyse soil organic carbon erosion - A case study from the Karoo rangelands

    Science.gov (United States)

    Krenz, Juliane; Greenwood, Philip; Heckrath, Goswin; Kuhn, Brigitte; Kuhn, Nikolaus

    2017-04-01

    Covering about 41 % of the Earth's Land Surface drylands provide a range of ecosystem services for more than one third of the world population. Threatened by climate change and incorrect land use their natural land cover is changing and land degradation is one of their major problems. The semi-arid rangelands of the Great Karoo region in South Africa are just one example of a region that has experienced a number of environmental changes. After European farmers settled in the late 18th century agricultural activities increased, leading to overgrazing and probably representing a trigger to land degradation. As a consequence of a higher water demand and shifting rainfall patterns many dams and small reservoirs have been constructed to provide drinking water for cattle or to facilitate irrigation during dry periods. High erosion rates lead to a fast filling-up of reservoirs and thereby reduced their storage capacities. Thus, most of the dams are nowadays dry (filled with sediment) or even breached. In this ongoing project, a combination of analytical methods that include drone imagery, landscape mapping, erosion modelling and sediment analysis have been employed to determine whether land degradation in the Karoo has resulted in the reversion from a net sink of C to a net source of C. Sediment deposits from three silted-up reservoirs were analysed for varying physicochemical parameters, in order to analyse and reconstruct erosional and depositional patterns. A sharp decrease in total carbon content with decreasing depth for two reservoirs suggests that land degradation during and after the post-European settlement most likely triggered erosion of the relatively fertile surface soils, which presumably in-filled the reservoirs. It is assumed that the carbon-rich bottom layers of the dam deposits originate from these eroded surface soils. Low organic Carbon (OC) content in the top layers of the reservoir in-fill, and in the eroded source areas, supports the assumption that

  5. Seedbed preparation influence on morphometric characteristics of perennial grasses of a semi-arid rangeland in Kenya

    OpenAIRE

    Opiyo, Francis EO; Ekaya, Wellington N; Nyariki, Dickson M; Mureithi, Stephen Mwangi

    2011-01-01

    Semi-arid rangelands in Kenya are an important source of forage for both domestic and wild animals. However, indigenous perennial grasses notably Cenchrus ciliaris (African foxtail grass), Eragrostis superba (Maasai love grass) and Enteropogon macrostachyus (Bush rye grass) are disappearing at an alarming rate. Efforts to re-introduce them through restoration programs have often yielded little success. This can partly be attributed to failure of topsoil to capture and store scarce water to me...

  6. Soil seed bank characteristics in relation to rangeland degradation in communal areas of the Eastern Cape, South Africa

    CSIR Research Space (South Africa)

    Lesoli, MS

    2010-07-01

    Full Text Available A soil seed bank is defined as seeds at or beneath the soil surface that are capable of germinating. Soil seed banks are important in ecosystems where grasses account for a large part of the vegetation. This has implications on the future vegetation...

  7. Criterion V: Legal, institutional, and economic framework for rangeland conservation and sustainable management [Chapter 6

    Science.gov (United States)

    Jonn E. Mitchell; Stan Hamiliton; Thomas Lustig; Kenneth Nelson; Tom Roberts; Brian Czech

    2010-01-01

    Laws, institutions, and economic policies play a large role in determining the sustainability of rangelands. They provide the basic framework from which many lasting decisions about rangeland management are made. The SRR has identified 10 primary indicators to assess how this framework influences the long-term health and productivity of rangeland in this country. The...

  8. Ecohydrologic impacts of rangeland fire on runoff and erosion: A literature synthesis

    Science.gov (United States)

    Frederick B. Pierson; C. Jason Williams

    2016-01-01

    Fire can dramatically influence rangeland hydrology and erosion by altering ecohydrologic relationships. This synthesis presents an ecohydrologic perspective on the effects of fire on rangeland runoff and erosion through a review of scientific literature spanning many decades. The objectives are: (1) to introduce rangeland hydrology and erosion concepts necessary for...

  9. Incorporating plant mortality and recruitment into rangeland management and assessment

    Science.gov (United States)

    Tony Svejcar; Jeremy James; Stuart Hardegree; Roger Sheley

    2014-01-01

    Rangeland management is largely focused on managing vegetation change. Objectives may include managing against change if the desired vegetation is in place, or attempting to create a shift in vegetation if the desired plant community is not present. There is a rich body of research documenting influences of disturbance and management on rangeland vegetation. However,...

  10. In-filled reservoirs serving as sediment archives to analyse soil organic carbon erosion - Taking a closer look at the Karoo rangelands

    Science.gov (United States)

    Krenz, Juliane; Greenwood, Philip; Kuhn, Brigitte; Heckrath, Goswin; Foster, Ian; Boardman, John; Meadows, Michael; Kuhn, Nikolaus

    2016-04-01

    The semi-arid rangelands of the Great Karoo region in South Africa, which are nowadays characterized by badlands on the foot slopes of upland areas and complex gully systems in valley bottoms, have experienced a number of environmental changes. With the settlement of European farmers in the late 18th century agricultural activities increased, leading to overgrazing which probably acted as a trigger to land degradation. As a consequence of higher water demands and shifting rainfall patterns, many dams and small reservoirs have been constructed to provide drinking water for cattle or to facilitate irrigation during dry periods. Most of these dams are now filled with sediment and many have become breached, revealing sediment archives that can be used to analyse land use changes as well as carbon erosion and deposition during the last ca. 100 years. In this ongoing project, a combination of analytical methods that include drone imagery, landscape mapping, erosion modelling and sediment analysis have been employed to trace back the sediment origin and redistribution within the catchment, setting a special focus on the carbon history. Sediment deposits from a silted-up reservoir were analysed for varying physicochemical parameters, in order to analyse erosional and depositional patterns. A sharp decrease in total carbon content with decreasing depth suggests that land degradation during and after the post-European settlement most likely triggered erosion of the relatively fertile surface soils which presumably in-filled the reservoirs. It is assumed that the carbon-rich bottom layers of the dam deposits originate from these eroded surface soils. A combination of erosion modelling and sediment analysis will be used to determine the source areas of the depositional material and might clarify the question if land degradation in the Karoo has resulted in its return from being a net sink of carbon into a net source of carbon.

  11. Rangeland dynamics in South Omo Zone of Southern Ethiopia: Assessment of rangeland condition in relation to altitude and Grazing types

    NARCIS (Netherlands)

    Terefe, A.; Ebro, A.; Tessema, Z.K.

    2010-01-01

    A study was undertaken in Hamer and Benna-Tsemay districts of the Southern Ethiopia with the objective to determine the condition of the rangelands for grazing animals as influenced by altitude and grazing types. The rangelands in each of the study districts were stratified based on altitude and

  12. Why is the influence of soil macrofauna on soil structure only considered by soil ecologists ?

    OpenAIRE

    Bottinelli, N.; Jouquet, Pascal; Capowiez, Y.; Podwojewski, Pascal; Grimaldi, Michel; Peng, X.

    2015-01-01

    These last twenty years have seen the development of an abundant literature on the influence of soil macrofauna on soil structure. Amongst these organisms, earthworms, termites and ants are considered to play a key role in regulating the physical, chemical and microbiological properties of soils. Due to these influential impacts, soil ecologists consider these soil macro-invertebrates as ‘soil engineers’ and their diversity and abundance are nowadays considered as relevant bioindi...

  13. Soil steaming effects on weed seedling emergence under the influence of soil type, soil moisture, soil structure and heat duration

    National Research Council Canada - National Science Library

    Melander, B; Kristensen, J.K

    2011-01-01

    .... This temperature range has a particular agronomic interest, and the present study aimed at investigating the influence of soil factors and heat duration on weed seed mortality of soil steaming targeting 60–80°C. Two soil types...

  14. Effects of Agaricus lilaceps fairy rings on soil aggregation and microbial community structure in relation to growth stimulation of western wheatgrass (Pascopyrum smithii) in Eastern Montana rangeland.

    Science.gov (United States)

    Caesar-Tonthat, The Can; Espeland, Erin; Caesar, Anthony J; Sainju, Upendra M; Lartey, Robert T; Gaskin, John F

    2013-07-01

    Stimulation of plant productivity caused by Agaricus fairy rings has been reported, but little is known about the effects of these fungi on soil aggregation and the microbial community structure, particularly the communities that can bind soil particles. We studied three concentric zones of Agaricus lilaceps fairy rings in Eastern Montana that stimulate western wheatgrass (Pascopyrum smithii): outside the ring (OUT), inside the ring (IN), and stimulated zone adjacent to the fungal fruiting bodies (SZ) to determine (1) soil aggregate proportion and stability, (2) the microbial community composition and the N-acetyl-β-D-glucosaminidase activity associated with bulk soil at 0-15 cm depth, (3) the predominant culturable bacterial communities that can bind to soil adhering to wheatgrass roots, and (4) the stimulation of wheatgrass production. In bulk soil, macroaggregates (4.75-2.00 and 2.00-0.25 mm) and aggregate stability increased in SZ compared to IN and OUT. The high ratio of fungal to bacteria (fatty acid methyl ester) and N-acetyl-β-D-glucosaminidase activity in SZ compared to IN and OUT suggest high fungal biomass. A soil sedimentation assay performed on the predominant isolates from root-adhering soil indicated more soil-binding bacteria in SZ than IN and OUT; Pseudomonas fluorescens and Stenotrophomonas maltophilia isolates predominated in SZ, whereas Bacillus spp. isolates predominated in IN and OUT. This study suggests that growth stimulation of wheatgrass in A. lilaceps fairy rings may be attributed to the activity of the fungus by enhancing soil aggregation of bulk soil at 0-15 cm depth and influencing the amount and functionality of specific predominant microbial communities in the wheatgrass root-adhering soil.

  15. Response of grasslands conversion to croplands on soil organic ...

    African Journals Online (AJOL)

    USER

    2010-03-22

    Mar 22, 2010 ... Frank AB, Tanaka DL, Hofmann L, Follett RF (1995). Soil carbon and nitrogen of Northern Great Plains grasslands as influenced by long-term grazing. J. rangeland manage. 48: 470-474. Guo L, Gifford R (2002). Soil carbon stocks and land use change: a meta analysis. Global Change Biol. (8): 345-360.

  16. Soil tillage influences on nitrogen conservation

    Energy Technology Data Exchange (ETDEWEB)

    Stenberg, M. [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Soil Sciences

    1998-12-31

    This thesis is focused on tillage effects with the emphasis on the risks of nitrogen leaching. Tillage operations strongly control the soil environment by altering the soil geometry. In addition, tillage determines the placement of crop residues. These effects influence many physical, chemical and biological properties of the soil and thereby the conditions for crop growth and the risk of nitrogen leaching. Results presented showed that when seedbed preparation was omitted, the lack of a firm seedbed bottom caused poor crop establishment under dry weather conditions. Poor crop establishment may result in low nitrogen use efficiency and thus increase the risk of leaching. It was also shown that it is possible to establish a ryegrass catch crop by undersowing in autumn-sown cereals in spring. Both soil structure and soil microbial processes changed when annual tillage practices were altered. On a weak-structured clay soil, cultivation to 12 cm instead of mouldboard ploughing to 20-25 cm improved soil structure and increased the microbial activity in the upper 12 cm. There was also an increase in yields, which promoted a better nitrogen utilization. However, an increase in potential nitrogen turnover may lead to a higher risk of nitrogen leaching. When a sandy soil was stubble cultivated or mouldboard ploughed soon after harvest in early autumn, soil mineral nitrogen content and nitrate leaching were higher than if it was ploughed in late autumn or in spring. Nitrogen mineralization was favoured by the higher soil temperatures early in autumn. Nitrate leaching was estimated by sampling of soil water with ceramic suction cups. Incorporation or removal of straw did not affect the soil nitrogen content or leaching rates. At late ploughing, the effect of a ryegrass catch crop on nitrate leaching was small. There is a need to obtain more data on both short-term and long-term effects of different tillage systems on nitrogen mineralization and immobilization in various field

  17. The influence of land use and cover changes on the pastoral rangeland systems of southern Ethiopia : how much woody cover is enough?

    OpenAIRE

    Mohammed, Hasen Yusuf

    2014-01-01

    The Borana rangelands in southern Ethiopia are facing deterioration caused by intensification of grazing and woody plant encroachment, resulting in marked reductions in pastoral production. This process affects the food security and livelihoods of the Borana pastoral people negatively. Woody plant encroachment might result in an increase in carbon (C) storage in these rangelands, which represents an important aspect for climate change mitigation potentials. However, it is unclear how much C i...

  18. Weather-centric rangeland revegetation planning

    Science.gov (United States)

    Hardegree, Stuart P.; Abatzoglou, John T.; Brunson, Mark W.; Germino, Matthew; Hegewisch, Katherine C.; Moffet, Corey A.; Pilliod, David S.; Roundy, Bruce A.; Boehm, Alex R.; Meredith, Gwendwr R.

    2018-01-01

    Invasive annual weeds negatively impact ecosystem services and pose a major conservation threat on semiarid rangelands throughout the western United States. Rehabilitation of these rangelands is challenging due to interannual climate and subseasonal weather variability that impacts seed germination, seedling survival and establishment, annual weed dynamics, wildfire frequency, and soil stability. Rehabilitation and restoration outcomes could be improved by adopting a weather-centric approach that uses the full spectrum of available site-specific weather information from historical observations, seasonal climate forecasts, and climate-change projections. Climate data can be used retrospectively to interpret success or failure of past seedings by describing seasonal and longer-term patterns of environmental variability subsequent to planting. A more detailed evaluation of weather impacts on site conditions may yield more flexible adaptive-management strategies for rangeland restoration and rehabilitation, as well as provide estimates of transition probabilities between desirable and undesirable vegetation states. Skillful seasonal climate forecasts could greatly improve the cost efficiency of management treatments by limiting revegetation activities to time periods where forecasts suggest higher probabilities of successful seedling establishment. Climate-change projections are key to the application of current environmental models for development of mitigation and adaptation strategies and for management practices that require a multidecadal planning horizon. Adoption of new weather technology will require collaboration between land managers and revegetation specialists and modifications to the way we currently plan and conduct rangeland rehabilitation and restoration in the Intermountain West.

  19. Influence of livestock grazing on C sequestration in semi-arid mixed-grass and short-grass rangelands

    Science.gov (United States)

    J.D. Reeder; G.E. Schuman

    2001-01-01

    We evaluated the effects of livestock grazing on C content of the plant-soil system (to 60 cm) of two semi-arid grasslands: a mixed-grass prairie (grazed 12 years), and a short-grass steppe (grazed 56 years). Grazing treatments included season-long grazing at heavy and light stocking rates, and non-grazed exclosures. Significantly higher soil C (0-30cm) was measured in...

  20. Influence of livestock grazing on C sequestration in semi-arid mixed-grass and short-grass rangelands.

    Science.gov (United States)

    Reeder, J D; Schuman, G E

    2002-01-01

    We evaluated the effects of livestock grazing on C content of the plant-soil system (to 60 cm) of two semi-arid grasslands: a mixed-grass prairie (grazed 12 years), and a short-grass steppe (grazed 56 years). Grazing treatments included season-long grazing at heavy and light stocking rates, and non-grazed exclosures. Significantly higher soil C (0-30cm) was measured in grazed pastures compared to non-grazed exclosures, although for the short-grass steppe higher soil C was observed with the heavy grazing treatment only. Excluding grazing caused an immobilization of C in excessive aboveground plant litter, and an increase in annual forbs and grasses which lack dense fibrous rooting systems conducive to soil organic matter formation and accumulation. Our data indicate that higher soil C with grazing was in part the result of more rapid annual shoot turnover, and redistribution of C within the plant-soil system as a result of changes in plant species composition.

  1. Influence of shrubs on soil chemical properties in Alxa desert steppe, China

    Science.gov (United States)

    Hua Fu; Shifang Pei; Yaming Chen; Changgui Wan

    2007-01-01

    Alxa desert steppe is one of severely the degraded rangelands in the Northwest China. Shrubs, as the dominant life form in the desert steppe, play an important role in protecting this region from further desertification. Chemical properties of three soil layers (0 to 10, 10 to 20 and 20 to 30 cm) at three locations (the clump center [A], in the periphery of shrub...

  2. Drought and rangelands.

    Science.gov (United States)

    Droughts are common and occur regularly in Oklahoma. They’re the most costly natural hazard to the United States, and estimates show a $6-$8 billion annual loss to the nation’s farmers and rancher. With the current drought impacting Oklahoma, people managing rangelands are concerned with the short...

  3. Evaluation of compost influence on soil water retention

    OpenAIRE

    Pavel Zemánek

    2011-01-01

    The experiment was focused on evaluation of influence of compost application on soil water retention. Soil retention is a major soil water property that governs soil functioning as a ecosystem. Soil moisture forms a major buffer against flooding, and water capacity in subsoil is a major factor for plant growth. The effects of changes in soil water retention depend on the proportions of the textural components and the amount of organic carbon present in the soil. During seasons of 2009 and 201...

  4. EVALUATION AND MAPPING OF RANGELANDS DEGRADATION USING REMOTELY SENSED DATA

    Directory of Open Access Journals (Sweden)

    Majid Ajorlo

    2005-05-01

    Full Text Available The empirical and scientifically documents prove that misuse of natural resource causes degradation in it. So natural resources conservation is important in approaching sustainable development aims. In current study, Landsat Thematic Mapper images and grazing gradient method have been used to map the extent and degree of rangeland degradation. In during ground-based data measuring, factors such as vegetation cover, litter, plant diversity, bare soil, and stone & gravels were estimated as biophysical indicators of degradation. The next stage, after geometric correction and doing some necessary pre-processing practices on the study area’s images; the best and suitable vegetation index has been selected to map rangeland degradation among the Normalized Difference Vegetation Index (NDVI, Soil Adjusted Vegetation Index (SAVI, and Perpendicular Vegetation Index (PVI. Then using suitable vegetation index and distance parameter was produced the rangelands degradation map. The results of ground-based data analysis reveal that there is a significant relation between increasing distance from critical points and plant diversity and also percentage of litter. Also there is significant relation between vegetation cover percent and distance from village, i.e. the vegetation cover percent increases by increasing distance from villages, while it wasn’t the same around the stock watering points. The result of analysis about bare soil and distance from critical point was the same to vegetation cover changes manner. Also there wasn’t significant relation between stones & gravels index and distance from critical points. The results of image processing show that, NDVI appears to be sensitive to vegetation changes along the grazing gradient and it can be suitable vegetation index to map rangeland degradation. The degradation map shows that there is high degradation around the critical points. These areas need urgent attention for soil conservation. Generally, it

  5. Simplifying ecological site verification, rangeland health assessments, and monitoring

    Science.gov (United States)

    During the past several decades, scientists and land managers in North America have increasingly recognized the importance of rangeland assessment relative to ecological potential based on soil and climate. The adoption of the site potential based “ecological site” system was recently formalized in ...

  6. Ranch business planning and resource monitoring for rangeland sustainability

    Science.gov (United States)

    Kristie A. Maczko; John A. Tanaka; Michael Smith; Cindy Garretson-Weibel; Stanley F. Hamilton; John E. Mitchell; Gene Fults; Charles Stanley; Dick Loper; Larry D. Bryant; J. K. (Rooter) Brite

    2012-01-01

    Aligning a rancher's business plan goals with the capability of the ranch's rangeland resources improves the viability and sustainability of family ranches. Strategically monitoring the condition of soil, water, vegetation, wildlife, livestock production, and economics helps inform business plan goals. Business planning and resource monitoring help keep...

  7. Defining function in rangelands of the Peddie district, Eastern Cape ...

    African Journals Online (AJOL)

    Surface soil conditions on the communal rangeland had higher organic carbon, nitrogen and phosphorus content. Following the analysis of satellite-derived vegetation indices, the commercial site had higher active green biomass (higher NDVI) and lower spatial diversity of near-infra red band (lower MSDI) than the ...

  8. Enhancing wind erosion monitoring and assessment for US rangelands

    Science.gov (United States)

    Wind erosion is a major resource concern for rangeland managers because it can impact soil health, ecosystem structure and function, hydrologic processes, agricultural production and air quality. Despite its significance, little is known about which landscapes are eroding, by how much, and when. T...

  9. Lessons from historical rangeland revegetation for today's restoration

    Science.gov (United States)

    Bruce A. Roundy

    1999-01-01

    Rangeland revegetation in the Western United States historically was applied at a large scale for soil conservation and forage production purposes. Principles of revegetation that have developed over years of research include matching site potential and plant materials adaption, use of appropriate seedbed preparation and sowing techniques, and development of large...

  10. Sediment dynamics and sources in a grazed hardwood rangeland watershed

    Science.gov (United States)

    Melvin R. George; Neil K. McDougald; Kenneth W. Tate; Royce Larsen

    2002-01-01

    From 1994 to 1998 we documented sediment transport dynamics and sources in a 137 ha grazed hardwood rangeland watershed on granitic soils at the San Joaquin Experimental Range in Madera County. Sediment transport for this watershed was determined by measuring total suspended solids, bedload and flow at an H-flume installed in 1994. Sediment movement as bedload is the...

  11. Climate change and North American rangelands: Assessment of mitigation and adaptation strategies

    Science.gov (United States)

    Linda A. Joyce; David D. Briske; Joel R. Brown; H. Wayne Polley; Bruce A. McCarl; Derek W. Bailey

    2013-01-01

    Recent climatic trends and climate model projections indicate that climate change will modify rangeland ecosystem functions and the services and livelihoods that they provision. Recent history has demonstrated that climatic variability has a strong influence on both ecological and social components of rangeland systems and that these systems possess substantial...

  12. Soil sealing degree as factor influencing urban soil contamination with polycyclic aromatic hydrocarbons (PAHs)

    OpenAIRE

    Mendyk Łukasz; Charzyński Przemysław

    2016-01-01

    The objective of the study was to determine role of soil sealing degree as the factor influencing soil contamination with polycyclic aromatic hydrocarbons (PAHs). The study area included four sampling sites located within the administrative boundaries of the Toruń city, Poland. Sampling procedure involved preparing soil pits representing three examples of soil sealing at each site: non-sealed soil as a control one (I) and two degrees of soil sealing: semi-pervious surface (II) and totally imp...

  13. In-filled reservoirs serving as sediment archives to analyse soil organic carbon erosion – Taking a closer look at the Karoo rangelands

    DEFF Research Database (Denmark)

    Krenz, Juliane; Greenwood, Philip; Kuhn, Brigitte

    The semi-arid rangelands of the Great Karoo region in South Africa, which are nowadays characterized by badlands on the foot slopes of upland areas and complex gully systems in valley bottoms, have experienced a number of environmental changes. With the settlement of European farmers in the late ......th century agricultural activities increased, leading to overgrazing which probably acted as a trigger to land degradation. As a consequence of higher water demands and shifting rainfall patterns, many dams and small reservoirs have been constructed to provide drinking water for cattle...... of analytical methods that include drone imagery, landscape mapping, erosion modelling and sediment analysis have been employed to trace back the sediment origin and redistribution within the catchment, setting a special focus on the carbon history. Sediment deposits from a silted-up reservoir were analysed...

  14. Soil steaming effects on weed seedling emergence under the influence of soil type, soil moisture, soil structure and heat duration

    OpenAIRE

    Melander, Bo; Kristensen, J K

    2011-01-01

    Soil steaming applied in bands is a new technology with the potential to radically lower the burden of hand-weeding intra-row weeds in non-herbicidalvegetable cropping. Preliminary studies with band-steaming have shown effective control of viable weed seeds when the maximum soil temperatures reach 60–80◦C. This temperature range has a particular agronomic interest,and the present study aimed at investigating the influence of soil factors and heat duration on weed seed mortality of soil steami...

  15. Biochar and Tillage Systems Influenced on Soil Physical Properties

    OpenAIRE

    Darusman, Darusman; Syahruddin, Syahruddin; Syakur, Syakur; Manfarizah, Manfarizah

    2017-01-01

    Biochar is known as huge carbon storage in the soil. In the soil, biochar absorbs CO2 from air and keep them for hundred years. In addition to prevention, reducing emission and green house effects, Biochar also contributes to soil productivity such as physical and chemical property improvement of the soil. How biochar amends soil physical properties combined with some tillage systems are imperative to find out. This study aimed to determine the influence of biochar and tillage systems on s...

  16. Influence of Vegetation Type and Land Management on Soil Organic Carbon Fractions in Gonbad Watershed, Hamadan

    Directory of Open Access Journals (Sweden)

    Khadije Salarinik

    2017-03-01

    Full Text Available Introduction: Soil organic matter is influenced strongly by vegetation cover and management, therefore it is proposed as the main indicator of soil quality and health. The changes in soil organic matter status occur much more rapidly in the labile pools than in organic C. Thus, labile pools can be used as early indicators of changes in total organic matter that will become more obvious in the longer term here. In addition, the labile fraction has a disproportionately large effect on nutrient-supplying capacity and structural stability of soils. Land management as well as soil and environmental conditions lead to the deployment of different plant communities in rangeland ecosystems, which in turn may have different effects on soil quality indicators. The main objective of this research was to investigate the influence of different vegetation covers on the quantity and quality of soil organic carbon fractions in Gonbad experimental watershed, Hamadan. Moreover, the seasonal changes of selected soil carbon fractions were investigated. Materials and Methods: Paired Gonbad watershed in Hamedan consists of two sub-basins: in control sub-basin no grazing management is applied, while in protected sub-basin, grazing has been restricted to a very short period in late autumn since 2002. Average annual precipitation and average annual temperature in the area are 304.4 mm and 9.5 °C, respectively (5. The soil cover of the watershed consists of TypicCalcixerepts, TypicHaploxerepts and Lithic Xerorthents (9. Five different vegetation typesof which, grasses (G, Astragalus-Bromus (A-B, Astragalus-Artemisia (A-A, Astragalus-Lactuca (A-L in protected sub-basin, and Astragalus-Euphorbia (A-E in control sub-basin, were selected. In addition, a formerly cultivated hilly land outside the watershed, now under rainfed wheat farming (RW was selected as a non-pasture vegetation type. All of the six vegetation types were similar in terms of soil parent materials and slope

  17. Opportunities for Integrated Ecological Analysis across Inland Australia with Standardised Data from Ausplots Rangelands.

    Directory of Open Access Journals (Sweden)

    Greg R Guerin

    Full Text Available Australian rangelands ecosystems cover 81% of the continent but are understudied and continental-scale research has been limited in part by a lack of precise data that are standardised between jurisdictions. We present a new dataset from AusPlots Rangelands that enables integrative rangelands analysis due to its geographic scope and standardised methodology. The method provides data on vegetation and soils, enabling comparison of a suite of metrics including fractional vegetation cover, basal area, and species richness, diversity, and composition. Cover estimates are robust and repeatable, allowing comparisons among environments and detection of modest change. The 442 field plots presented here span a rainfall gradient of 129-1437 mm Mean annual precipitation with varying seasonality. Vegetation measurements include vouchered vascular plant species, growth form, basal area, height, cover and substrate type from 1010 point intercepts as well as systematically recorded absences, which are useful for predictive modelling and validation of remote sensing applications. Leaf and soil samples are sampled for downstream chemical and genomic analysis. We overview the sampling of vegetation parameters and environments, applying the data to the question of how species abundance distributions (SADs vary over climatic gradients, a key question for the influence of environmental change on ecosystem processes. We found linear relationships between SAD shape and rainfall within grassland and shrubland communities, indicating more uneven abundance in deserts and suggesting relative abundance may shift as a consequence of climate change, resulting in altered diversity and ecosystem function. The standardised data of AusPlots enables such analyses at large spatial scales, and the testing of predictions through time with longitudinal sampling. In future, the AusPlots field program will be directed towards improving coverage of space, under-represented environments

  18. Opportunities for Integrated Ecological Analysis across Inland Australia with Standardised Data from Ausplots Rangelands.

    Science.gov (United States)

    Guerin, Greg R; Sparrow, Ben; Tokmakoff, Andrew; Smyth, Anita; Leitch, Emrys; Baruch, Zdravko; Lowe, Andrew J

    2017-01-01

    Australian rangelands ecosystems cover 81% of the continent but are understudied and continental-scale research has been limited in part by a lack of precise data that are standardised between jurisdictions. We present a new dataset from AusPlots Rangelands that enables integrative rangelands analysis due to its geographic scope and standardised methodology. The method provides data on vegetation and soils, enabling comparison of a suite of metrics including fractional vegetation cover, basal area, and species richness, diversity, and composition. Cover estimates are robust and repeatable, allowing comparisons among environments and detection of modest change. The 442 field plots presented here span a rainfall gradient of 129-1437 mm Mean annual precipitation with varying seasonality. Vegetation measurements include vouchered vascular plant species, growth form, basal area, height, cover and substrate type from 1010 point intercepts as well as systematically recorded absences, which are useful for predictive modelling and validation of remote sensing applications. Leaf and soil samples are sampled for downstream chemical and genomic analysis. We overview the sampling of vegetation parameters and environments, applying the data to the question of how species abundance distributions (SADs) vary over climatic gradients, a key question for the influence of environmental change on ecosystem processes. We found linear relationships between SAD shape and rainfall within grassland and shrubland communities, indicating more uneven abundance in deserts and suggesting relative abundance may shift as a consequence of climate change, resulting in altered diversity and ecosystem function. The standardised data of AusPlots enables such analyses at large spatial scales, and the testing of predictions through time with longitudinal sampling. In future, the AusPlots field program will be directed towards improving coverage of space, under-represented environments, vegetation types

  19. Land Conversion Dynamics in the Borana Rangelands of Southern Ethiopia: An Integrated Assessment Using Remote Sensing Techniques and Field Survey Data

    Directory of Open Access Journals (Sweden)

    Michael Elias

    2015-01-01

    Full Text Available Conversion of rangelands into cultivated land is one of the main challenges affecting the management of rangelands in Ethiopia. In order to inform policy makers about trends in land-use conversion, this study examined the drivers, trends, and impacts of land conversions in five locations selected in the Borana rangelands of Southern Ethiopia. This study integrated survey interviews from agro-pastoralists, participatory appraisals, rainfall data, and remotely sensed satellite data from Landsat images taken in 1985 and 2011. Results indicate that there is a marked increase in cultivated land in some of the study sites while in the other sites there is a slight reduction. The bare lands increased in some parts of the study sites though there was slight recovery of grassland in some of the degraded areas. Settlement areas with permanent housing increased. Woodland vegetation decreased except on mountain escarpments where there were slight gains. The results further show that, during this period, bushland decreased while at the same time grassland increased. Shrub/grassland with seasonally flooded areas increased in the bottomlands. Inhabitants interviewed in the study areas perceived land use and land cover changes to be driven by interplay of recurrent drought, loss of pasture, food insecurity, and decline in income. Changes in policies that govern natural resources have influence the land use change in this area and the expansion of cultivation. Expansion of cultivation practices upon rangelands has resulting in significant loss of vegetation biomass and soil erosion, thereby precipitating rangeland degradation. The results provide comprehensive insights regarding the influence of internal and external drivers of land conversion that should be considered when making decisions for land use planning.

  20. influence of soil type differences on the distribution of dtpa

    African Journals Online (AJOL)

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    properties. Metal activity in the soil solution is generally influenced by metal equilibria among clay minerals, organic matter, hydrous oxides of. Fe, Mn, and Al, and ..... Soil mixing by the soil fauna will have also similar effect. Farmers at Akaki commonly use DAP to fertilize their vegetables, sometimes together with urea.

  1. The influence of soil properties on the development of Cephalcia ...

    African Journals Online (AJOL)

    Different soil samples collected from three different cedars forests in Lebanon were incubated with prepupae of C. tannourinensis under laboratory conditions. The effect of soil origins and properties on prepupal mortality, annual diapause and multiple years diapause cycles were analyzed. The influence of soil moisture and ...

  2. Whither the Rangeland?: Protection and conversion in California's Rangeland ecosystems.

    Directory of Open Access Journals (Sweden)

    D Richard Cameron

    Full Text Available Land use change in rangeland ecosystems is pervasive throughout the western United States with widespread ecological, social and economic implications. In California, rangeland habitats have high biodiversity value, provide significant habitat connectivity and form the foundation for a number of ecosystem services. To comprehensively assess the conservation status of these habitats, we analyzed the extent and drivers of habitat loss and the degree of protection against future loss across a 13.5 M ha study area in California. We analyzed rangeland conversion between 1984 and 2008 using time series GIS data and classified resulting land uses with aerial imagery. In total, over 195,000 hectares of rangeland habitats were converted during this period. The majority of conversions were to residential and associated commercial development (49% of the area converted, but agricultural intensification was surprisingly extensive and diverse (40% across six categories. Voluntary enrollment in an agricultural tax incentive program provided widespread protection from residential and commercial conversions across 37% of the remaining rangeland habitat extent (7.5 M ha, though this program did not protect rangeland from conversion to more intensive agricultural uses. Additionally, 24% of the remaining rangeland was protected by private conservation organizations or public agencies through land or easement ownership while 38% had no protection status at all. By developing a spatial method to analyze the drivers of loss and patterns of protection, this study demonstrates a novel approach to prioritize conservation strategies and implementation locations to avert habitat conversion. We propose that this approach can be used in other ecosystem types, and can serve as a regional conservation baseline assessment to focus strategies to effect widespread, cost-effective conservation solutions.

  3. Rangeland dynamics in South Omo Zone of Southern Ethiopia: Assessment of rangeland condition in relation to altitude and Grazing types

    OpenAIRE

    Terefe, A.; Ebro, A.; Tessema, Z.K.

    2010-01-01

    A study was undertaken in Hamer and Benna-Tsemay districts of the Southern Ethiopia with the objective to determine the condition of the rangelands for grazing animals as influenced by altitude and grazing types. The rangelands in each of the study districts were stratified based on altitude and grazing types. In the study districts, a total of 32, 3, 2, 7 and 29 species of grasses, legumes, sedges, other herbaceous plants and woody species were identified, respectively. The common and/or dom...

  4. Rangelands: Where anthromes meet their limits

    Science.gov (United States)

    Defining rangelands as anthromes enabled Ellis and Ramankutty (2008) to conclude that more than three-quarters of Earth’s land is anthropogenic; without rangelands, this figure would have been less than half. They classified all lands grazed by domestic livestock as rangelands, provided that human p...

  5. A systematic review of US rangeland science

    Science.gov (United States)

    Rangeland science aims to create knowledge to sustain rangeland social-ecological systems over the long term. Range science has made substantial progress on understanding ecological dynamics of rangeland systems and the management practices that sustain them, and these findings have been systematica...

  6. Sustainable rangelands ecosystem goods and services

    Science.gov (United States)

    Kristie Maczko; Lorie Hidinger

    2008-01-01

    The Sustainable Rangelands Roundtable (SRR) recognizes the unique contributions rangeland resources make to the nation's wellbeing. To communicate the importance of these commodity and amenity values, SRR participants developed this primer on rangeland ecosystem goods and services. It summarizes the history of the nation's relationship with and reliance upon...

  7. Influence of soil compaction on microfungal community structure in two soil types in Bartin Province, Turkey.

    Science.gov (United States)

    Kara, Omer; Bolat, Ilyas

    2007-10-01

    Soil compaction negatively influences physical properties of soil (bulk density and pore space), and may consequently limit soil microfungi, which are significant for nutrient bioavailability. We measured microfungal community responses to compaction in a sandy loam and a clay loam soil at picnic sites. Soil bulk density increased significantly in the compacted samples. However, microfungal numbers and community composition were unrelated to changes in soil bulk density. With increases in bulk density from 1.22 to 1.37 g cm(-3) in the clay soil and from 1.38 to 1.54 g cm(-3) in the sandy loam soil, the total number of fungi declined or showed insignificant increases. In the compacted samples as well as the control sites, the most frequently occurring genera in the clay soil were Penicillium, Aspergillus, and Gliocladium. However, the most prominent feature occurring within the sandy loam soil was the exhibition of the greatest increase in the frequency of the Fusarium genus. When comparing compacted and control soils, fungal community composition corresponded more closely within each soil texture. The two microfungal soil communities, therefore, tolerated compaction. In contrast, a difference occurred in the fungal communities between the two soil textures. This is more likely due to the variability in the controlling factors of microfungal abundance and composition, such as soil characteristics, tree species, and competitive ability of fungal genera.

  8. Climate impacts on agriculture: Implications for forage and rangeland production

    Energy Technology Data Exchange (ETDEWEB)

    Izaurralde, Roberto C.; Thomson, Allison M.; Morgan, Jack; Fay, Philip; Polley, Wayne; Hatfield, Jerry L.

    2011-04-19

    Projections of temperature and precipitation patterns across the United States during the next 50 years anticipate a 1.5 to 2°C warming and a slight increase in precipitation as a result of global climate change. There have been relatively few studies of climate change impacts on pasture and rangeland (grazingland) species compared to those on crop species, despite the economic and ecological importance of the former. Here we review the literature on pastureland and rangeland species to rising CO2 and climate change (temperature, and precipitation) and discuss plant and management factors likely to influence pastureland and rangeland responses to change (e.g., community composition, plant competition, perennial growth habit, seasonal productivity, and management methods). Overall, the response of pasture species to increased [CO2] is consistent with the general response of C3 and C4 type vegetation, although significant exceptions exist. Both pastureland and rangeland species should exhibit an acceleration of metabolism and development due to earlier onset of spring green-up and longer growing seasons. However, in the studies reviewed here, C3 pasture species increased their photosynthetic rates by up to 40% while C4 species exhibited no increase in photosynthesis. In general, it is expected that increases in [CO2] and precipitation would enhance rangeland net primary production (NPP) while increased air temperatures would either increase or decrease NPP. Much of this uncertainty in response is due to uncertain future projections of precipitation, both globally and regionally. For example, if annual precipitation changes little or declines, rangeland plant response to warming temperatures and rising [CO2] may be neutral or may decline due to increased water stress. This review reveals the need for comprehensive studies of climate change impacts on the pasture ecosystem including grazing regimes, mutualistic relationships (e.g., plant roots-nematodes; N

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

    Science.gov (United States)

    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

  10. Composted manure application promotes long-term invasion of semi-arid rangeland by Bromus tectorum

    Science.gov (United States)

    Composted organic matter derived from sewage treatment facilities or livestock manure from feedlots is often applied to rangelands of western North America to increase soil fertility, forage production, forage quality, and soil carbon (C) storage. This practice can have a number of undesirable side ...

  11. Influence of soil properties on copper toxicity for two soil invertebrates.

    Science.gov (United States)

    Criel, Peggy; Lock, Koen; Eeckhout, Hilde Van; Oorts, Koen; Smolders, Erik; Janssen, Colin R

    2008-08-01

    Although a large body of evidence indicates that metal toxicity to soil organisms is affected by physicochemical soil properties, use of this knowledge in ecological risk assessments is limited because of the lack of a model applicable to a wide range of soils. To study the effect of soil characteristics on the toxicity of copper to terrestrial invertebrates, chronic toxicity tests with Eisenia fetida and Folsomia candida were performed in 19 European field soils. These soils were carefully selected to cover the range of toxicity-influencing parameters encountered in the European Union. Toxicity values varied greatly among soils, with 28-d median effect concentrations ranging from 72.0 to 781 mg Cu/kg dry weight for E. fetida and from 45.4 to 2,270 mg Cu/kg dry weight for F. candida. For both species, variation in copper toxicity values was best explained by differences in the actual cation-exchange capacity (CEC) at soil pH. Using the obtained regression algorithms, the observed toxicity could, in most cases, be predicted within a factor of two for E. fetida and within a factor of three for F. candida. The developed models were validated in three additional European field soils, a standard artificial soil and a standard field soil. The presented regression equations, based on the actual CEC, offer an easy-to-apply method for taking the influence of soil properties on metal toxicity into account.

  12. Plant species influence on soil C after afforestation of Mediterranean degraded soils

    Science.gov (United States)

    Dominguez, Maria T.; García-Vargas, Carlos; Madejón, Engracia; Marañón, Teodoro

    2015-04-01

    Increasing C sequestration in terrestrial ecosystems is one of the main current environmental challenges to mitigate climate change. Afforestation of degraded and contaminated lands is one of the key strategies to achieve an increase in C sequestration in ecosystems. Plant species differ in their mechanisms of C-fixation, C allocation into different plant organs, and interaction with soil microorganisms, all these factors influencing the dynamics of soil C following the afforestation of degraded soils. In this work we examine the influence of different woody plant species on soil C dynamics in degraded and afforested Mediterranean soils. The soils were former agricultural lands that were polluted by a mining accident and later afforested with different native plant species. We analysed the effect of four of these species (Olea europaea var. sylvestris Brot., Populus alba L., Pistacia lentiscus L. and Retama sphaerocarpa (L.) Boiss.) on different soil C fractions, soil nutrient availability, microbial activity (soil enzyme activities) and soil CO2 fluxes 15 years after the establishment of the plantations. Results suggest that the influence of the planted trees and shrubs is still limited, being more pronounced in the more acidic and nutrient-poor soils. Litter accumulation varied among species, with the highest C accumulated in the litter under the deciduous species (Populus alba L.). No differences were observed in the amount of total soil organic C among the studied species, or in the concentrations of phenols and sugars in the dissolved organic C (DOC), which might have indicated differences in the biodegradability of the DOC. Microbial biomass and activity was highly influenced by soil pH, and plant species had a significant influence on soil pH in the more acidic site. Soil CO2 fluxes were more influenced by the plant species than total soil C content. Our results suggest that changes in total soil C stocks after the afforestation of degraded Mediterranean

  13. Soil water and mineral nitrogen content as influenced by crop ...

    African Journals Online (AJOL)

    ) and wheat–medic rotation (McWMcW) and tillage, conventional-till (CT), minimum-till (MT), no-till (NT) and zero-till (ZT) were studied. Crop rotation did not influence soil moisture content. Soil water content in CT tended to be lower compared ...

  14. Influence of lokpa cattle market wastes on agricultural soil quality ...

    African Journals Online (AJOL)

    This paper examined the influence of Lokpa cattle market waste on soil properties. Soil samples were collected from the Central, 3 and 6 m Northwards, Southwards, Eastwards and Westwards of Lokpa cattle market, Umuneochi Local Government Area of Abia State, Nigeria at a depth of 0 to 25 cm (Sample A) and 26 to 50 ...

  15. Influence of amendments on soil structure and soil loss under ...

    African Journals Online (AJOL)

    GREGORY

    2010-09-13

    Sep 13, 2010 ... Adding each of the three polymers to the soil increased infiltration by an average of 0.813 mm min-1; an increase of 25.6% over the control. Increasing the number of polymer applications gradually increased water infiltration rates until the infiltration levelled off under the PPA and. UR treatments, whereas ...

  16. Influence of amendments on soil structure and soil loss under ...

    African Journals Online (AJOL)

    Macromolecule polymers are significant types of chemical amendments because of their special structure, useful functions and low cost. ... These three amendments have broad potential for soil and water conservation; however, the duration of their effect and the optimal application quantities need to be researched further.

  17. Influence of physical and chemical properties of different soil types on optimal soil moisture for tillage

    Directory of Open Access Journals (Sweden)

    Vladimir Zebec

    2017-01-01

    Full Text Available Soil plasticity is the area of soil consistency, i.e. it represents a change in soil condition due to different soil moisture influenced by external forces activity. Consistency determines soil resistance in tillage, therefore, the aim of the research was to determine the optimum soil moisture condition for tillage and the influence of the chemical and physical properties of the arable land horizons on the soil plasticity on three different types of soil (fluvisol, luvisol and humic glaysol. Statistically significant differences were found between all examined soil types, such as the content of clay particles, the density of packaging and the actual and substitution acidity, the cation exchange capacity and the content of calcium. There were also statistically significant differences between the examined types of soil for the plasticity limit, liquid limit and the plasticity index. The average established value of plasticity limit as an important element for determining the optimal moment of soil tillage was 18.9% mass on fluvisol, 24.0% mass on luvisol and 28.6% mass on humic glaysol. Very significant positive direction correlation with plasticity limits was shown by organic matter, clay, fine silt, magnesium, sodium and calcium, while very significant negative direction correlation was shown by hydrolytic acidity, coarse sand, fine sand and coarse silt. Created regression models can estimate the optimal soil moisture condition for soil cultivation based on the basic soil properties. The model precision is significantly increased by introducing a greater number of agrochemical and agrophysical soil properties, and the additional precision of the model can be increased by soil type data.

  18. Influence of biochar on soil pore structure and denitrification

    Science.gov (United States)

    Maenhout, Peter; Sleutel, Steven; Ameloot, Nele; De Neve, Stefaan

    2014-05-01

    Incorporation of biochar into soils has frequently been found to reduce soil emission of the greenhouse gas N2O, formed as an intermediate during microbial denitrification. The exact mechanism that regulates N2O emission reduction after biochar incorporation is still unknown and diverse hypotheses on either chemical, physical or biological controls over soil denitrification exist. The porous structure of biochar may directly and indirectly influence the soil pore structure upon its incorporation. Firstly biochar may increase soil aeration and thereby reduce denitrification which requires an anaerobic atmosphere to continue. In order to investigate this hypothesis we incorporated 4 biochar types in a sandy loam soil and collected undisturbed soil cores after 8 months of field incorporation. We then crushed half of the soil cores and replaced them. We followed N2O emissions from undisturbed and disturbed biochar amended soil cores by GC headspace analysis. From the disturbed soil cores no emission reduction was expected because soil pore structure was severely disrupted. However, both disturbed and undisturbed soil cores showed emission reductions when compared to the soil cores without biochar amendment. This allowed us to reject the hypothesis that biochar would affect soil denitrification through increased soil aeration. We moved to investigate a second hypothesis, viz. 'Through the retention of water in its finer pores, biochar could create local anaerobic 'denitrification hot spots' in soils. It could be hypothesized that the final further reduction of N2O into N2 is stimulated. We tested this hypothesis by comparing N2+N2O (acetylene inhibition) and N2O emissions from undisturbed soil cores with or without biochar amended, at 70 and 90 % WFPS. At 70% WFPS we expected higher N2 emissions in biochar amended soils compared to the unamended control cores, through the action of anaerobic hot spots in biochar. In contrast, at 90% WFPS anaerobicity would be general in

  19. The Role of Rural Communities in Conservation of Rangelands in Mahneshan Township

    Directory of Open Access Journals (Sweden)

    Kobra Karimi

    2016-05-01

    Full Text Available The aim of this study was to investigate the action of rangeland-depended livestock holders regarding rangeland conservation, including protection and rehabilitation activities and to analyse relevant influencing factors, using a mixed method of survey and case study. The data were collected through analysing existing documents, focus groups, semi-structured and structured interviews using questionnaires submitted to 204 rural livestock holders in the Mahneshan Township. The quantitative data were analysed using SPSS and AMOS software. According to the results farmers’ knowledge regarding the role, importance and factors affecting rangeland degradation was relatively high, however they had a low level of knowledge and action about mechanical conservation techniques. The action of livestock holders in terms of biological conservation activities and grazing management showed a positive and signifincat corrletaion with variables such as implementing of rangeland projects, their interaction with external institutions, participating in extension training courses, education level and irrigated and rainfed agricultural land size. Moreover, based on a path analysis, 37% of the variance of the farmers’ actions regarding the rangeland conservation was explained by the variables such as rangeland rehabilitation actions, farmers’ conservation knowledge, farmers’ interaction with natural resources experts, beekeeping, and participating in extension training courses. Promotional and extension activities and farmers’ interaction with experts have a positive effect in enhancing farmers’ knowledge and actions for sustainable rangeland use and conservation.

  20. Climate change impacts on selected global rangeland ecosystem services.

    Science.gov (United States)

    Boone, Randall B; Conant, Richard T; Sircely, Jason; Thornton, Philip K; Herrero, Mario

    2018-03-01

    Rangelands are Earth's dominant land cover and are important providers of ecosystem services. Reliance on rangelands is projected to grow, thus understanding the sensitivity of rangelands to future climates is essential. We used a new ecosystem model of moderate complexity that allows, for the first time, to quantify global changes expected in rangelands under future climates. The mean global annual net primary production (NPP) may decline by 10 g C m -2  year -1 in 2050 under Representative Concentration Pathway (RCP) 8.5, but herbaceous NPP is projected to increase slightly (i.e., average of 3 g C m -2  year -1 ). Responses vary substantially from place-to-place, with large increases in annual productivity projected in northern regions (e.g., a 21% increase in productivity in the US and Canada) and large declines in western Africa (-46% in sub-Saharan western Africa) and Australia (-17%). Soil organic carbon is projected to increase in Australia (9%), the Middle East (14%), and central Asia (16%) and decline in many African savannas (e.g., -18% in sub-Saharan western Africa). Livestock are projected to decline 7.5 to 9.6%, an economic loss of from $9.7 to $12.6 billion. Our results suggest that forage production in Africa is sensitive to changes in climate, which will have substantial impacts on the livelihoods of the more than 180 million people who raise livestock on those rangelands. Our approach and the simulation tool presented here offer considerable potential for forecasting future conditions, highlight regions of concern, and support analyses where costs and benefits of adaptations and policies may be quantified. Otherwise, the technical options and policy and enabling environment that are needed to facilitate widespread adaptation may be very difficult to elucidate. © 2017 John Wiley & Sons Ltd.

  1. Soil sealing degree as factor influencing urban soil contamination with polycyclic aromatic hydrocarbons (PAHs

    Directory of Open Access Journals (Sweden)

    Mendyk Łukasz

    2016-03-01

    Full Text Available The objective of the study was to determine role of soil sealing degree as the factor influencing soil contamination with polycyclic aromatic hydrocarbons (PAHs. The study area included four sampling sites located within the administrative boundaries of the Toruń city, Poland. Sampling procedure involved preparing soil pits representing three examples of soil sealing at each site: non-sealed soil as a control one (I and two degrees of soil sealing: semi-pervious surface (II and totally impervious surface (III. Together with basic properties defined with standard procedures (particle size distribution, pH, LOI, content of carbonates content of selected PAHs was determined by dichloromethane extraction using gas chromatography with mass spectrometric detection (GC-MS. Obtained results show that urban soils in the city of Toruń are contaminated with polycyclic aromatic hydrocarbons. Soil sealing degree has a strong influence on the soil contamination with polycyclic aromatic hydrocarbons. Totally sealed soils are better preserved from atmospheric pollution including PAHs. Combustion of grass/wood/coal was the main source of determined PAHs content in examined soils.

  2. Topographic variability influences the carbon sequestration potential of arable soils

    DEFF Research Database (Denmark)

    Chirinda, Ngoni; Elsgaard, Lars; Thomsen, Ingrid Kaag

    2012-01-01

    There is presently limited knowledge on the influence of field spatial variability on the carbon (C) sink-source relationships in arable landscapes. This is accompanied by the fact that our understanding of soil profile C dynamics is also limited. This study aimed at investigating how spatial...... variability along a short catena influences C sinksource relationships and temporal dynamics of CO2 concentrations in soils. In spring 2011, soil samples were collected from topsoil (2-5.5 cm) and subsoil (38-41.5 cm) horizons at upslope and footslope positions in a Danish winter wheat field on a sandy loam...... soil developed on glacial till. Bulk densities and C concentrations of the soils were characterized. From June 2011, gas samples were collected at least bimonthly from the same slope positions in four spatial replicates using stainless steel needles that were permanently installed at 5, 10, 20 and 30...

  3. Influence of soil moisture content on surface albedo and soil thermal ...

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Earth System Science; Volume 123; Issue 5. Influence of soil moisture content on surface albedo and soil thermal ... Department of Physics, Government College for Women, Thiruvananthapuram 695 014, Kerala, India. Kerala State Council for Science, Technology and Environment, Sasthra ...

  4. Rehabilitation of Degraded Rangeland in Drylands by Prickly Pear (Opuntia ficus-indica L. Plantations: Effect on Soil and Spontaneous Vegetation

    Directory of Open Access Journals (Sweden)

    Souad Neffar

    2013-12-01

    Full Text Available In arid and semi-arid lands, the spiny prickly pear (Opuntia ficus-indica is an outstanding plant for soil conservation and restoration. To determine the role of Opuntia ficus-indica on vegetation recovery process in desertified areas of Southern Tebessa (Northeast Algeria, we investigated the effect of prickly pear plantation age and some soil properties (grain size, pH, electrical conductivity, organic matter, total nitrogen, available phosphorus, and CaCO3 equivalents on native plant community. Vegetation cover and plant diversity were assessed by calculating the number of individual plants (N, species richness (S, their ratio (N/S, Shannon index, and Evenness in prickly pear plantation plots of different ages (control, 5 and 20 years. Even if surveyed soil parameters did not differ significantly among O. ficus-indica plantations, results of ANOVA testing the effect of Opuntia plantations on native vegetation traits revealed significant variation for plant abundance (P < 0.0001, N/S ratio (P = 0.003 and vegetation cover (P < 0.0001. Vegetation cover differed significantly with both prickly-pear plantation age (P = 0.031 and seasons (P = 0.019. Tukey's tests revealed that all vegetation traits were significantly higher on prickly pear plantations than in control plots. Multiple comparisons also showed that plant abundance, N/S ratio and vegetation cover were significantly different between both young and old plantations and the controls. Prickly pear cultures facilitated the colonization and development of herbaceous species by ameliorating the severe environmental conditions. In conclusion, the facilitative effect of O. ficus-indica has been clearly demonstrated for both abundance and cover of native vegetation.

  5. [Degradation of carbendazim in paddy soil and the influencing factors].

    Science.gov (United States)

    Xiao, Wen-Dan; Yang, Xiao-E; Li, Ting-Qiang

    2012-11-01

    The influences of microorganism, soil moisture and cadmium (Cd) on degradation of carbendazim in paddy soil were investigated with laboratory microcosm experiments. The results showed that the half-life of carbendazim (5.0 mg x kg(-1) and 10.0 mg x kg(-1)) in sterilized soils was 12.6-13.8 times of those in non-sterilized soils. The half-life of carbendazim was decreased by 32.1%-37.1% when the soils were inoculated with carbendazim-degrading strains. When the soil moisture was increased from 40% to 60% or 80% of water holding capacity, the half life of carbendazim was decreased by 46.2% or 74.0%, respectively. Low level of Cd (5 mg x kg(-1)) enhanced the degradation of carbendazim in soils with half-life time decreased by 32.1%-52.4%, but high level of Cd (50 mg x kg(-1)) inhibited the degradation of carbendazim in soils with half-life time increased by 92.6%-103.0%. For the soils inoculated with carbendazim-degrading strains, the half life of carbendazim was decreased by 34.0% -34.4% with the addition of low level of Cd (5.0 mg x kg(-1)), while the half life time was increased by 74.4% -109.4% with the addition of high level of Cd (50 mg x kg(-1)). The results demonstrate that indigenous microorganisms is a critical factor that influences carbendazim degradation in soils, and that carbendazim-degrading strains, high soil moisture and low Cd level enhance the degradation of carbendazim.

  6. The soil microbiome influences grapevine-associated microbiota.

    Science.gov (United States)

    Zarraonaindia, Iratxe; Owens, Sarah M; Weisenhorn, Pamela; West, Kristin; Hampton-Marcell, Jarrad; Lax, Simon; Bokulich, Nicholas A; Mills, David A; Martin, Gilles; Taghavi, Safiyh; van der Lelie, Daniel; Gilbert, Jack A

    2015-03-24

    Grapevine is a well-studied, economically relevant crop, whose associated bacteria could influence its organoleptic properties. In this study, the spatial and temporal dynamics of the bacterial communities associated with grapevine organs (leaves, flowers, grapes, and roots) and soils were characterized over two growing seasons to determine the influence of vine cultivar, edaphic parameters, vine developmental stage (dormancy, flowering, preharvest), and vineyard. Belowground bacterial communities differed significantly from those aboveground, and yet the communities associated with leaves, flowers, and grapes shared a greater proportion of taxa with soil communities than with each other, suggesting that soil may serve as a bacterial reservoir. A subset of soil microorganisms, including root colonizers significantly enriched in plant growth-promoting bacteria and related functional genes, were selected by the grapevine. In addition to plant selective pressure, the structure of soil and root microbiota was significantly influenced by soil pH and C:N ratio, and changes in leaf- and grape-associated microbiota were correlated with soil carbon and showed interannual variation even at small spatial scales. Diazotrophic bacteria, e.g., Rhizobiaceae and Bradyrhizobium spp., were significantly more abundant in soil samples and root samples of specific vineyards. Vine-associated microbial assemblages were influenced by myriad factors that shape their composition and structure, but the majority of organ-associated taxa originated in the soil, and their distribution reflected the influence of highly localized biogeographic factors and vineyard management. Vine-associated bacterial communities may play specific roles in the productivity and disease resistance of their host plant. Also, the bacterial communities on grapes have the potential to influence the organoleptic properties of the wine, contributing to a regional terroir. Understanding that factors that influence these

  7. Influence of low- and high-frequency electrical heating on biodegrading microorganisms in soil: soil respiration.

    Science.gov (United States)

    Roland, Ulf; Holzer, Frank; Kopinke, Frank-Dieter

    2013-01-01

    The influence of electrical heating on microbiological processes in soil has been studied to evaluate the potential for enhancing biodegradation of pollutants by controlling the temperature. A frequency of 50 Hz (power line frequency) was applied for resistive heating. Dielectric heating was realized using a frequency of 13.56 MHz (radio frequency). Both techniques were compared with conventional heating in a water bath. For experiments in laboratory and full scale, a model soil and a contaminated original soil were used. It was shown that under conditions capable for heating soil to 35 degrees C or even 60 degrees C, soil respiration as a measure for microbial activity was not hindered by electrical heating when temperature and moisture content were comparable with conventional heating. The variations of soil respiration were reversible upon temperature changes. Under certain conditions, periodical fluctuations of microbiological activity were observed. Several possible explanations including chronobiology are discussed without being able to provide an unambiguous interpretation for this effect.

  8. Enhancing wind erosion monitoring and assessment for U.S. rangelands

    Science.gov (United States)

    Webb, Nicholas P.; Van Zee, Justin W.; Karl, Jason W.; Herrick, Jeffrey E.; Courtright, Ericha M.; Billings, Benjamin J.; Boyd, Robert C.; Chappell, Adrian; Duniway, Michael C.; Derner, Justin D.; Hand, Jenny L.; Kachergis, Emily; McCord, Sarah E.; Newingham, Beth A.; Pierson, Frederick B.; Steiner, Jean L.; Tatarko, John; Tedela, Negussie H.; Toledo, David; Van Pelt, R. Scott

    2017-01-01

    On the GroundWind erosion is a major resource concern for rangeland managers because it can impact soil health, ecosystem structure and function, hydrologic processes, agricultural production, and air quality.Despite its significance, little is known about which landscapes are eroding, by how much, and when.The National Wind Erosion Research Network was established in 2014 to develop tools for monitoring and assessing wind erosion and dust emissions across the United States.The Network, currently consisting of 13 sites, creates opportunities to enhance existing rangeland soil, vegetation, and air quality monitoring programs.Decision-support tools developed by the Network will improve the prediction and management of wind erosion across rangeland ecosystems.

  9. Resource management in rangeland

    Science.gov (United States)

    Adequate assessments of vast expanses of rangeland—a primary prerequisite to effective conservation planning—requires landscape-scale evaluations that accurately represent the resources (e.g., soil, vegetation, wildlife, water ), the structure and function of the resource-providing systems, and the ...

  10. Modeling the influence of organic acids on soil weathering

    Science.gov (United States)

    Lawrence, Corey R.; Harden, Jennifer W.; Maher, Kate

    2014-01-01

    Biological inputs and organic matter cycling have long been regarded as important factors in the physical and chemical development of soils. In particular, the extent to which low molecular weight organic acids, such as oxalate, influence geochemical reactions has been widely studied. Although the effects of organic acids are diverse, there is strong evidence that organic acids accelerate the dissolution of some minerals. However, the influence of organic acids at the field-scale and over the timescales of soil development has not been evaluated in detail. In this study, a reactive-transport model of soil chemical weathering and pedogenic development was used to quantify the extent to which organic acid cycling controls mineral dissolution rates and long-term patterns of chemical weathering. Specifically, oxalic acid was added to simulations of soil development to investigate a well-studied chronosequence of soils near Santa Cruz, CA. The model formulation includes organic acid input, transport, decomposition, organic-metal aqueous complexation and mineral surface complexation in various combinations. Results suggest that although organic acid reactions accelerate mineral dissolution rates near the soil surface, the net response is an overall decrease in chemical weathering. Model results demonstrate the importance of organic acid input concentrations, fluid flow, decomposition and secondary mineral precipitation rates on the evolution of mineral weathering fronts. In particular, model soil profile evolution is sensitive to kaolinite precipitation and oxalate decomposition rates. The soil profile-scale modeling presented here provides insights into the influence of organic carbon cycling on soil weathering and pedogenesis and supports the need for further field-scale measurements of the flux and speciation of reactive organic compounds.

  11. Modeling the influence of organic acids on soil weathering

    Science.gov (United States)

    Lawrence, Corey; Harden, Jennifer; Maher, Kate

    2014-08-01

    Biological inputs and organic matter cycling have long been regarded as important factors in the physical and chemical development of soils. In particular, the extent to which low molecular weight organic acids, such as oxalate, influence geochemical reactions has been widely studied. Although the effects of organic acids are diverse, there is strong evidence that organic acids accelerate the dissolution of some minerals. However, the influence of organic acids at the field-scale and over the timescales of soil development has not been evaluated in detail. In this study, a reactive-transport model of soil chemical weathering and pedogenic development was used to quantify the extent to which organic acid cycling controls mineral dissolution rates and long-term patterns of chemical weathering. Specifically, oxalic acid was added to simulations of soil development to investigate a well-studied chronosequence of soils near Santa Cruz, CA. The model formulation includes organic acid input, transport, decomposition, organic-metal aqueous complexation and mineral surface complexation in various combinations. Results suggest that although organic acid reactions accelerate mineral dissolution rates near the soil surface, the net response is an overall decrease in chemical weathering. Model results demonstrate the importance of organic acid input concentrations, fluid flow, decomposition and secondary mineral precipitation rates on the evolution of mineral weathering fronts. In particular, model soil profile evolution is sensitive to kaolinite precipitation and oxalate decomposition rates. The soil profile-scale modeling presented here provides insights into the influence of organic carbon cycling on soil weathering and pedogenesis and supports the need for further field-scale measurements of the flux and speciation of reactive organic compounds.

  12. Soil Influence in Seismic Design of Bridges in Cuba

    OpenAIRE

    Dario Candebat Sánchez; Guillermo Godínez Melgares; Luis Felipe Caballero Cornier; Zulima Caridad Rivera Álvarez

    2017-01-01

    Soil geological conditions affect directly the seismic structural behavior of bridges. This work shows the importance of determining the site coefficient, a parameter used by Cuban seismic code for considering the influence of soil in the structural response. The research is based in the results obtained from the application of geophysical seismic refraction method. It is presented as an example a bridge located on Granma highway in Santiago de Cuba city, showing variations in lithology prese...

  13. Adaptive management of rangeland systems

    Science.gov (United States)

    Allen, Craig R.; Angeler, David G.; Fontaine, Joseph J.; Garmestani, Ahjond S.; Hart, Noelle M.; Pope, Kevin L.; Twidwell, Dirac

    2017-01-01

    Adaptive management is an approach to natural resource management that uses structured learning to reduce uncertainties for the improvement of management over time. The origins of adaptive management are linked to ideas of resilience theory and complex systems. Rangeland management is particularly well suited for the application of adaptive management, having sufficient controllability and reducible uncertainties. Adaptive management applies the tools of structured decision making and requires monitoring, evaluation, and adjustment of management. Adaptive governance, involving sharing of power and knowledge among relevant stakeholders, is often required to address conflict situations. Natural resource laws and regulations can present a barrier to adaptive management when requirements for legal certainty are met with environmental uncertainty. However, adaptive management is possible, as illustrated by two cases presented in this chapter. Despite challenges and limitations, when applied appropriately adaptive management leads to improved management through structured learning, and rangeland management is an area in which adaptive management shows promise and should be further explored.

  14. Earth observation for rangeland monitoring

    CSIR Research Space (South Africa)

    Ramoelo, Abel

    2012-10-01

    Full Text Available for the methodology is presented in Figure 1. Figure 1: Conceptual framework for the development of grass nutrient estimation models, using remote sensing at various scales Earth Observation for Rangeland Monitoring DR A RAMOELO, DR M CHO AND DR R MATHIEU CSIR... and canopy N conforms to the underlying geology (Figure 2). ACKNOWLEDGEMENT The authors would like to thank the Department of Science and Technology which contributed financially to this work through the grant ?Earth Observation Application Development...

  15. Chemical changes induced by pH manipulations of volcanic ash-influenced soils

    Science.gov (United States)

    Deborah Page-Dumroese; Dennis Ferguson; Paul McDaniel; Jodi Johnson-Maynard

    2007-01-01

    Data from volcanic ash-influenced soils indicates that soil pH may change by as much as 3 units during a year. The effects of these changes on soil chemical properties are not well understood. Our study examined soil chemical changes after artificially altering soil pH of ash-influenced soils in a laboratory. Soil from the surface (0-5 cm) and subsurface (10-15 cm)...

  16. Influence of management history and landscape variables on soil organic carbon and soil redistribution

    Science.gov (United States)

    Venteris, E.R.; McCarty, G.W.; Ritchie, J.C.; Gish, T.

    2004-01-01

    Controlled studies to investigate the interaction between crop growth, soil properties, hydrology, and management practices are common in agronomy. These sites (much as with real world farmland) often have complex management histories and topographic variability that must be considered. In 1993 an interdisiplinary study was started for a 20-ha site in Beltsville, MD. Soil cores (271) were collected in 1999 in a 30-m grid (with 5-m nesting) and analyzed as part of the site characterization. Soil organic carbon (SOC) and 137Cesium (137Cs) were measured. Analysis of aerial photography from 1992 and of farm management records revealed that part of the site had been maintained as a swine pasture and the other portion as cropped land. Soil properties, particularly soil redistribution and SOC, show large differences in mean values between the two areas. Mass C is 0.8 kg m -2 greater in the pasture area than in the cropped portion. The pasture area is primarily a deposition site, whereas the crop area is dominated by erosion. Management influence is suggested, but topographic variability confounds interpretation. Soil organic carbon is spatially structured, with a regionalized variable of 120 m. 137Cs activity lacks spatial structure, suggesting disturbance of the profile by animal activity and past structures such as swine shelters and roads. Neither SOC nor 137Cs were strongly correlated to terrain parameters, crop yields, or a seasonal soil moisture index predicted from crop yields. SOC and 137Cs were weakly correlated (r2 ???0.2, F-test P-value 0.001), suggesting that soil transport controls, in part, SOC distribution. The study illustrates the importance of past site history when interpreting the landscape distribution of soil properties, especially those strongly influenced by human activity. Confounding variables, complex soil hydrology, and incomplete documentation of land use history make definitive interpretations of the processes behind the spatial distributions

  17. Influences of winery-distillery waste compost stability and soil type on soil carbon dynamics in amended soils.

    Science.gov (United States)

    Bustamante, M A; Said-Pullicino, D; Paredes, C; Cecilia, J A; Moral, R

    2010-10-01

    The application of organic materials to replenish soil organic matter and improve soil structure and fertility has become a common agronomic practice. This research deals with the effects of soil amendment with winery and distillery waste composts on organic carbon (C) mineralisation in two arable soils. A sandy-loam and clay-loam soil were treated and incubated with a number organic materials obtained from the co-composting of different proportions of grape stalk, grape marc, exhausted grape marc and vinasse, with sewage sludge or animal manure. Moreover, the effect of compost stability on C mineralisation dynamics was studied by applying organic materials from different stages of the composting process. The results obtained showed that the addition of exogenous organic matter stimulated microbial growth, enhanced soil respiration and increased water-extractable C contents in both soils, particularly in the days immediately following amendment. The initial composition of the different organic materials used, especially for the mature samples, and the texture of the receiving soil did not influence significantly the C mineralisation final values, with around 11-20% of the added organic C being mineralised over the first 140 days. However, the contribution of organic amendment to the labile organic C pool, maximum rates of soil respiration, as well as the extent of initial disturbance of the soil microbiota were all found to be related to the degree of organic matter stability. Moreover, irrespective of the type and stability of the organic amendment, the mineralogical composition of the receiving soil was found to significantly influence its resilience in such systems. (c) 2010 Elsevier Ltd. All rights reserved.

  18. Influence of Herbicide Triasulfuron on Soil Microbial Community in an Unamended Soil and a Soil Amended with Organic Residues

    Science.gov (United States)

    Pose-Juan, Eva; Igual, José M.; Sánchez-Martín, María J.; Rodríguez-Cruz, M. S.

    2017-01-01

    The effect of organic amendments and pesticides on a soil microbial community has garnered considerable interest due to the involvement of microorganisms in numerous soil conservation and maintenance reactions. The aim of this work was to assess the influence on a soil microbial community of the simultaneous application of the herbicide triasulfuron at three doses (2, 10, and 50 mg kg-1), with an organic amendment [sewage sludge (SS) or green compost (GC)]. Dissipation kinetics, soil microbial biomass, dehydrogenase activity (DHA) and respiration, and the profile of phospholipid fatty acids (PLFAs) extracted from the soil, were determined in unamended (S) soil and amended (S+SS and S+GC) ones. Triasulfuron dissipation followed the single first-order kinetics model. Half-life (DT50) values were higher in the amended soils than in the unamended one for the 10 and 50 mg kg-1 doses. The dissipation rates were lower in the S+GC soil for the three herbicide doses applied. In general, soil biomass, DHA and respiration values increased in SS- and GC-amended soils compared to the unamended one. DHA values decreased (S and S+SS) or increased (S+GC) with the incubation time of soil with herbicide at the different doses applied. Respiration values increased with the herbicide doses applied and decreased with the incubation time, although maximum values were obtained for soils treated with the highest dose after 70 days of incubation. PLFA analysis indicated different effects of triasulfuron on the soil microbial community structure depending on the organic amendments. While the increasing triasulfuron doses resulted in deeper alterations in the S soil, the time after triasulfuron application was the most important variation in the S+SS and S+GC soils. The overall results indicate that the soil amendment has an effect on herbicide dissipation rate and the soil microbial community. Initially, a high dose of triasulfuron had detrimental effects on the soil microbial community

  19. Influence of Herbicide Triasulfuron on Soil Microbial Community in an Unamended Soil and a Soil Amended with Organic Residues.

    Science.gov (United States)

    Pose-Juan, Eva; Igual, José M; Sánchez-Martín, María J; Rodríguez-Cruz, M S

    2017-01-01

    The effect of organic amendments and pesticides on a soil microbial community has garnered considerable interest due to the involvement of microorganisms in numerous soil conservation and maintenance reactions. The aim of this work was to assess the influence on a soil microbial community of the simultaneous application of the herbicide triasulfuron at three doses (2, 10, and 50 mg kg-1), with an organic amendment [sewage sludge (SS) or green compost (GC)]. Dissipation kinetics, soil microbial biomass, dehydrogenase activity (DHA) and respiration, and the profile of phospholipid fatty acids (PLFAs) extracted from the soil, were determined in unamended (S) soil and amended (S+SS and S+GC) ones. Triasulfuron dissipation followed the single first-order kinetics model. Half-life (DT50) values were higher in the amended soils than in the unamended one for the 10 and 50 mg kg-1 doses. The dissipation rates were lower in the S+GC soil for the three herbicide doses applied. In general, soil biomass, DHA and respiration values increased in SS- and GC-amended soils compared to the unamended one. DHA values decreased (S and S+SS) or increased (S+GC) with the incubation time of soil with herbicide at the different doses applied. Respiration values increased with the herbicide doses applied and decreased with the incubation time, although maximum values were obtained for soils treated with the highest dose after 70 days of incubation. PLFA analysis indicated different effects of triasulfuron on the soil microbial community structure depending on the organic amendments. While the increasing triasulfuron doses resulted in deeper alterations in the S soil, the time after triasulfuron application was the most important variation in the S+SS and S+GC soils. The overall results indicate that the soil amendment has an effect on herbicide dissipation rate and the soil microbial community. Initially, a high dose of triasulfuron had detrimental effects on the soil microbial community

  20. The Role of Indigenous Ecological Knowledge in Managing Rangelands Sustainably in Northern Iran

    Directory of Open Access Journals (Sweden)

    Mehdi Ghorbani

    2013-06-01

    Full Text Available Pastoralists' knowledge of adaptive rangeland management in Iran has long been only selectively analyzed and documented. This study attempts to rectify that by outlining the indigenous ecological knowledge of the pastoralists of Nariyan village in the Taleghan region of northern Iran, and by evaluating the influence of such knowledge on rangeland management. Local herd owners operate according to traditional herding practices; their knowledge of rangeland plants and principles of sustainable rangeland management is indigenous and is based on centuries of experience and observation. Their in-depth knowledge covers the medicinal properties of various local plant species and the palatability of the most salient forage species in terms of sustaining the sheep and goats that are their livelihood. This study investigates some of the traditional strategies of rangeland management used in the Taleghan region, the rationale and timing of livestock rotation in the rangelands, local landscape classification, and local know-how in animal husbandry, all of which are indispensable in contributing to the pastoralists' survival and maintenance of the local environment.

  1. Influence of soil structure on nutrient cycling using microfluidic techniques

    Science.gov (United States)

    Arellano Caicedo, Carlos; Aleklett, Kristin; Ohlsson, Pelle; Hammer, Edith

    2017-04-01

    The rising of atmospheric CO2 levels and its effects on global warming make it necessary to understand the elements that regulate such levels and furthermore try to slow down the CO2 accumulation in the atmosphere. The exchange of carbon between soil and atmosphere plays a significant role in the atmospheric carbon budget. Soil organisms deposit organic compounds on and in soil aggregates, either as exudates or dead remains. Much of this dead organic material is quickly recycled, but a portion, however, will stay in the soil for long term. Evidence suggests that micro-scale biogeochemical interactions could play a highly significant role in degradation or persistence of organic matter in soils, thus, soil physical structure might play a decisive role in preventing accessibility of nutrients to microorganisms. For studying effects of spatial microstructure on soil nutrient cycles, we have constructed artificial habitats for microbes that simulate soil structures. Microfluidic, so called Lab-on-a-chip technologies, are one of the tools used to achieve our purpose. Such micro-habitats consist of pillar structures of difference density and surface area, tunnels with increasing depth, and mazes of increasing complexity to simulate different stages of soil aggregation. Using microscopy and analytical chemistry, we can follow the growth of microorganisms inoculated into the "soil chip" as well as the chemical degradation of organic matter compounds provided as nutrient source. In this way, we want to be able to predict how soil structure influences soil microbial activity leading to different effects on the carbon cycle. Our first results of a chip inoculated with natural soil showed a succession of organisms colonizing channels leading to dead-end arenas, starting with a high presence of bacteria inside the chip during the first days. Fungal hyphae growth gradually inside the channels until it finally occupied the big majority of the spaces isolating bacteria which

  2. Influence of the Soil Genesis on Physical and Mechanical Properties

    Directory of Open Access Journals (Sweden)

    Marian Marschalko

    2013-01-01

    Full Text Available The paper deals with the influence of soil genesis on the physical-mechanical properties. The presented case study was conducted in the region of the Ostrava Basin where there is a varied genetic composition of the Quaternary geological structure on the underlying Neogeneous sediments which are sediments of analogous granulometry but different genesis. In this study, 7827 soil samples of an eolian, fluvial, glacial, and deluvial origin and their laboratory analyses results were used. The study identified different values in certain cases, mostly in coarser-grained foundation soils, such as sandy loam S4 (MS and clayey sand F4 (CS. The soils of the fluvial origin manifest different values than other genetic types. Next, based on regression analyses, dependence was proved neither on the deposition depth (depth of samples nor from the point of view of the individual foundation soil classes or the genetic types. The contribution of the paper is to point at the influence of genesis on the foundation soil properties so that engineering geologists and geotechnicians pay more attention to the genesis during engineering-geological and geotechnical investigations.

  3. Criteria and indicators for sustainable rangeland management

    Science.gov (United States)

    John E. Mitchell

    2010-01-01

    The concept of sustainable management encompasses ecological, economic, and social criteria and indicators (C&I) for monitoring and assessing the association between maintaining a healthy rangeland base and sustaining the well-being of communities and economies. During a series of meetings from 2001 to 2003, the Sustainable Rangelands Roundtable (SRR) developed...

  4. Development of a computerised rangelands resource information ...

    African Journals Online (AJOL)

    Data on livestock inventory, rangelands resources, and status of land degradation were integrated to produce a computerised resource information system for Swaziland, which will assist in decision making for monitoring and management of rangelands resources; its application is demonstrated. The resource information ...

  5. The Vale rangeland rehabilitation program: an evaluation.

    Science.gov (United States)

    Harold F. Heady

    1988-01-01

    This manuscript discusses the initiation, execution, and outcome of an 11-year (1962-1972) rangeland rehabilitation program in southeastern Oregon. Res. Bull. PNW-RB-070 (1977) is updated with 1986 measurements and evaluations of vegetational conditions, wildlife, recreational use, livestock grazing, and management of public rangelands. The mix of multiple uses has...

  6. Current situation of rangelands in Mexico

    Science.gov (United States)

    Alicia Melgoza-Castillo

    2006-01-01

    Rangelands are natural areas with certain characteristics that make them unsuitable for agriculture. They include several types of vegetation such as deserts, grasslands, shrubs, forests, and riparian areas. Cattle ranching, along with the products and services it engenders, is a prime activity that rangelands have traditionally supported.

  7. Tackling 'the most avoided issue\\'*: communal rangeland ...

    African Journals Online (AJOL)

    Facilitator training for communal rangeland management should include social skills, the social context of communal rangelands and novice facilitators should be supported by mentors. There is a need for greater financial support and law enforcement from the state in the area of communal grazing management. Keywords: ...

  8. A Dynamic Model of California's Hardwood Rangelands

    Science.gov (United States)

    Richard B. Standiford; Richard E. Howitt

    1991-01-01

    Low profitability of hardwood rangeland management, and oak tree harvesting for firewood markets and forage enhancement has led to concern about the long-term sustainability of the oak resource on rangelands. New markets for recreational hunting may give value to oaks for the habitat they provide for game species, and broaden the economic base for managers. A ranch...

  9. Applying animal behavior to arid rangeland mangement

    Science.gov (United States)

    Livestock production is one of many demands placed on today’s arid rangelands. Therefore, understanding plant and animal biology and their effects on biotic and abiotic landscape components is fundamental if rangelands are to remain ecologically sustainable. One limiting factor to accomplishing posi...

  10. Influence of soil type on half-highbush blueberry productivity

    Directory of Open Access Journals (Sweden)

    Tea Tasa

    2012-12-01

    Vaccinium spp. cultivars (five- and six-year-old plants were used in the experiment: ‘Aino’, ‘Alvar’, ‘Arne’, and ‘Northblue’. Environmental conditions exercised a considerable influence on biological processes of half-highbush blueberry, at the same time, a genotype-based variation was observed. Cultivar ‘Northblue’ had a higher yield in mineral soil and ‘Aino’ had the highest yield in peat soil considering the average of two years. The peat soil condition in the harvested peat field provided a better supply of nutrients for blueberry bushes compared to mineral soil and this, in its turn, secured better growth and a higher yield of blueberry bushes.

  11. Mapping Erosion and Salinity Risk Categories Using GIS and the Rangeland Hydrology Erosion Model

    Science.gov (United States)

    Up to fifteen percent of rangelands in the state of Utah in the United States are classified as being in severely eroding condition. Some of these degraded lands are located on saline, erodible soils of the Mancos Shale formation. This results in a disproportionate contribution of sediment, salinity...

  12. Effects of climate change on rangeland vegetation in the northern Rockies [Chapter 6

    Science.gov (United States)

    Matt C. Reeves; Mary E. Manning; Jeff P. DiBenedetto; Kyle A. Palmquist; William K. Lauenroth; John B. Bradford; Daniel R. Schlaepfer

    2017-01-01

    A longer growing season with climate change is expected to increase net primary productivity of many rangeland types, especially those dominated by grasses, although responses will depend on local climate and soil conditions. Elevated atmospheric carbon dioxide may increase water use efficiency and productivity of some species. In many cases, increasing wildfire...

  13. Multi-scale wind erosion monitoring and assessment for US rangelands

    Science.gov (United States)

    Wind erosion is a major resource concern for rangeland managers. Although wind erosion is a naturally occurring process in many drylands, land use activities, and land management in particular, can accelerate wind-driven soil loss – impacting ecosystem dynamics and agricultural production, air quali...

  14. Climate-change adaptation on rangelands: Linking regional exposure with diverse adaptive capacity

    Science.gov (United States)

    David D. Briske; Linda A. Joyce; H. Wayne Polley; Joel R. Brown; Klaus Wolter; Jack A. Morgan; Bruce A. McCarl; Derek W. Bailey

    2015-01-01

    The ecological consequences of climate change are predicted to vary greatly throughout US rangelands. Projections show warming and drying in the southern Great Plains and the Southwest, warmer and drier summers with reduced winter snowpack in the Northwest, and warmer and wetter conditions in the northern Great Plains. Primarily through their combined effects on soil...

  15. Influence of sward defoliation and soil disturbance on seedling ...

    African Journals Online (AJOL)

    Development of vegetation from seed requires a seed bank, germination, emergence and subsequent seedling survival. Reports on the influence of a number of practicably feasible treatments to the vegetation and soil on emergence and survival of grass seedlings in the Southern Tall Grassveld of Natal. Illustrates with ...

  16. Environment influence on water characteristics of soils in two semi ...

    African Journals Online (AJOL)

    Environment influence on water characteristics of soils in two semi-arid catchments in Laikipia, Kenya. G Kironchi, SM Kinyali, JP Mbuvi. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT. Article Metrics. Metrics Loading ... Metrics ...

  17. Incorporating grazing into an eco-hydrologic model: Simulating coupled human and natural systems in rangelands

    Science.gov (United States)

    Reyes, J. J.; Liu, M.; Tague, C.; Choate, J. S.; Evans, R. D.; Johnson, K. A.; Adam, J. C.

    2013-12-01

    Rangelands provide an opportunity to investigate the coupled feedbacks between human activities and natural ecosystems. These areas comprise at least one-third of the Earth's surface and provide ecological support for birds, insects, wildlife and agricultural animals including grazing lands for livestock. Capturing the interactions among water, carbon, and nitrogen cycles within the context of regional scale patterns of climate and management is important to understand interactions, responses, and feedbacks between rangeland systems and humans, as well as provide relevant information to stakeholders and policymakers. The overarching objective of this research is to understand the full consequences, intended and unintended, of human activities and climate over time in rangelands by incorporating dynamics related to rangeland management into an eco-hydrologic model that also incorporates biogeochemical and soil processes. Here we evaluate our model over ungrazed and grazed sites for different rangeland ecosystems. The Regional Hydro-ecologic Simulation System (RHESSys) is a process-based, watershed-scale model that couples water with carbon and nitrogen cycles. Climate, soil, vegetation, and management effects within the watershed are represented in a nested landscape hierarchy to account for heterogeneity and the lateral movement of water and nutrients. We incorporated a daily time-series of plant biomass loss from rangeland to represent grazing. The TRY Plant Trait Database was used to parameterize genera of shrubs and grasses in different rangeland types, such as tallgrass prairie, Intermountain West cold desert, and shortgrass steppe. In addition, other model parameters captured the reallocation of carbon and nutrients after grass defoliation. Initial simulations were conducted at the Curlew Valley site in northern Utah, a former International Geosphere-Biosphere Programme Desert Biome site. We found that grasses were most sensitive to model parameters affecting

  18. How do peat type, sand addition and soil moisture influence the soil organic matter mineralization in anthropogenically disturbed organic soils?

    Science.gov (United States)

    Säurich, Annelie; Tiemeyer, Bärbel; Don, Axel; Burkart, Stefan

    2017-04-01

    Drained peatlands are hotspots of carbon dioxide (CO2) emissions from agriculture. As a consequence of both drainage induced mineralization and anthropogenic sand mixing, large areas of former peatlands under agricultural use contain soil organic carbon (SOC) at the boundary between mineral and organic soils. Studies on SOC dynamics of such "low carbon organic soils" are rare as the focus of previous studies was mainly either on mineral soils or "true" peat soil. However, the variability of CO2 emissions increases with disturbance and therefore, we have yet to understand the reasons behind the relatively high CO2 emissions of these soils. Peat properties, soil organic matter (SOM) quality and water content are obviously influencing the rate of CO2 emissions, but a systematic evaluation of the hydrological and biogeochemical drivers for mineralization of disturbed peatlands is missing. With this incubation experiment, we aim at assessing the drivers of the high variability of CO2 emissions from strongly anthropogenically disturbed organic soil by systematically comparing strongly degraded peat with and without addition of sand under different moisture conditions and for different peat types. The selection of samples was based on results of a previous incubation study, using disturbed samples from the German Agricultural Soil Inventory. We sampled undisturbed soil columns from topsoil and subsoil (three replicates of each) of ten peatland sites all used as grassland. Peat types comprise six fens (sedge, Phragmites and wood peat) and four bogs (Sphagnum peat). All sites have an intact peat horizon that is permanently below groundwater level and a strongly disturbed topsoil horizon. Three of the fen and two of the bog sites have a topsoil horizon altered by sand-mixing. In addition the soil profile was mapped and samples for the determination of soil hydraulic properties were collected. All 64 soil columns (including four additional reference samples) will be installed

  19. Valuation of rangeland ecosystem services

    Science.gov (United States)

    Gascoigne, W.R.

    2011-01-01

    Economic valuation lends itself well to the anthropocentric orientation of ecosystem services. An economic perspective on ecosystems portrays them as natural assets providing a flow of goods and services valuable to individuals and society collectively. A few examples include the purification of drinking water, reduced risk from flooding and other extreme events, pollination of agricultural crops, climate regulation, and recreation opportunities from plant and animal habitat maintenance, among many others. Once these goods and services are identified and quantified, they can be monetized to complete the valuation process. The monetization of ecosystem goods and services (in the form of dollars) provides a common metric that allows for cross-comparison of attributes and evaluation of differing ecological scenarios. Complicating the monetization process is the fact that most of these goods and services are public and non-market in nature; meaning they are non-rival and non-exclusive and are typically not sold in a traditional market setting where monetary values are revealed. Instead, one must employ non-market valuation techniques, with primary valuation methods typically being very time and resource consuming, intimidating to non-economists, and often impractical. For these reasons, benefit transfer methods have gained popularity. This methodology harnesses the primary collection results of existing studies to make inferences about the economic values of non-market goods and services at an alternative policy site (in place and/or in time). For instance, if a primary valuation study on oak reestablishment on rangelands in southern California yielded a value of $30 per-acre associated with water regulation, this result can be transferred, with some adjustments, to say something about the value of an acre of oaks on rangelands in northern portions of the state. The economic valuation of rangeland ecosystem services has many roles. Economic values may be used as input

  20. Influence of soil amendments made from digestate on soil physics and the growth of spring wheat

    Science.gov (United States)

    Dietrich, Nils; Knoop, Christine; Raab, Thomas; Krümmelbein, Julia

    2016-04-01

    Every year 13 million tons of organic wastes accumulate in Germany. These wastes are a potential alternative for the production of energy in biogas plants, especially because the financial subventions for the cultivation of renewable resources for energy production were omitted in 2014. The production of energy from biomass and organic wastes in biogas plants results in the accumulation of digestate and therefore causes the need for a sustainable strategy of the utilization of these residues. Within the scope of the BMBF-funded project 'VeNGA - Investigations for recovery and nutrient use as well as soil and plant-related effects of digestate from waste fermentation' the application of processed digestate as soil amendments is examined. Therefore we tested four different mechanical treatment processes (rolled pellets, pressed pellets, shredded compost and sieved compost) to produce soil amendments from digestate with regard to their impact on soil physics, soil chemistry and the interactions between plants and soil. Pot experiments with soil amendments were performed in the greenhouse experiment with spring wheat and in field trials with millet, mustard and forage rye. After the first year of the experiment, preliminary results indicate a positive effect of the sieved compost and the rolled pellets on biomass yield of spring wheat as compared to the other variations. First results from the Investigation on soil physics show that rolled pellets have a positive effect on the soil properties by influencing size and distribution of pores resulting in an increased water holding capacity. Further ongoing enhancements of the physical and chemical properties of the soil amendments indicate promising results regarding the ecological effects by increased root growth of spring wheat.

  1. INFLUENCE OF AN ORGANIC WASTE USED AS SOIL AMENDMENT ON TRIAZINE HERBICIDE SORPTION AND AVAILABILITY

    Science.gov (United States)

    In this work we have studied the influence of an organic waste generated in the olive oil mill process, used as soil amendment, on atrazine and terbuthylazine sorption and availability in soil. The soils studied were two sandy soils with different origin, Spain and Minnesota and the effect of soil a...

  2. Factors controlling gully erosion at different spatial and temporal scales in rangelands of SW Spain

    Science.gov (United States)

    Gómez Gutiérrez, Á.; Schnabel, S.; Lavado Contador, J. F.; Pulido Fernández, M.

    2009-04-01

    Mediterranean climate with Atlantic influences. Results showed that at the catchment scale, and for a short period (1-10 years), rainfall and soil moisture were the most important factors controlling gully erosion rates. In fact, gully erosion was highly related with the rainfall amount (r=0,90), with the number of times event discharge exceeded 1000 cubic meters (r=0,76) and with the number of times peak discharge exceeded 100 l/s (r=0,72). However, when the temporal scale was extended to several decades (from 1945 to 2006), land use and vegetation cover (specially the extension of cultivated area and livestock density) proved to be the most important factors determining the area affected by gullying. With respect to the spatial variation of gullying at the regional scale, the model results indicate lithology as being the most important variable, followed by vegetation structure and summer rainfall. This model was able to explain a large portion of the spatial distribution of gullies at the regional scale. Concluding, at different spatial and temporal scales the importance of factors which determine gully erosion intensity, extension and rates varies notably. At the short-term rainfall and runoff dynamics and the moisture content of the sediments are the dominant factors, whereas at the medium-term land use and vegetation cover become more important. At the regional scale lithology and vegetation turned out to be the dominant factors in determining the location of areas susceptible to gully erosion in rangelands of Extremadura.

  3. Influence of long-term fertilization on soil physicochemical properties in a brown soil

    Science.gov (United States)

    Li, Dongdong; Luo, Peiyu; Han, Xiaori; Yang, Jinfeng

    2018-01-01

    This study aims to explore the influence on soil physicochemical properties under a 38-y long-term fertilization in a brown soil. Soil samples (0-20 cm)were taken from the six treatments of the long-term fertilization trial in October 2016:no fertilizer (CK), N1(mineral nitrogen fertilizer), N1P (mineral nitrogen and phosphate fertilizer), N1PK (mineral nitrogen, phosphate and potassic fertilizer), pig manure (M2), M2N1P (pig manure, mineral nitrogen and phosphate fertilizer).The results showed thatthe long-term application of chemical fertilizers reduced soil pH value, while the application of organic fertilizers increased pH value. Fertilization significantly increased the content of AHN, TN and SOM. Compared with the CK treatment and chemical fertilizer treatments, organic fertilizer treatments significantly increased the content of AP and TP. The content of AK and TK were no significant difference in different treatment.

  4. Retention of silver nano-particles and silver ions in calcareous soils: Influence of soil properties.

    Science.gov (United States)

    Rahmatpour, Samaneh; Shirvani, Mehran; Mosaddeghi, Mohammad R; Bazarganipour, Mehdi

    2017-05-15

    The rapid production and application of silver nanoparticles (AgNPs) have led to significant release of AgNPs into the terrestrial environments. Once released into the soil, AgNPs could enter into different interactions with soil particles which play key roles in controlling the fate and transport of these nanoparticles. In spite of that, experimental studies on the retention of AgNPs in soils are very scarce. Hence, the key objective of this research was to find out the retention behavior of AgNPs and Ag(I) ions in a range of calcareous soils. A second objective was to determine the extent to which the physico-chemical properties of the soils influence the Ag retention parameters. To this end, isothermal batch experiments were used to determine the retention of Poly(vinylpyrrolidinone)-capped AgNPs (PVP-AgNPs) and Ag(I) ions by nine calcareous soils with a diversity of physico-chemical properties. The results revealed that the retention data for both PVP-AgNPs and Ag(I) ions were well described by the classical Freundlich and Langmuir isothermal equations. The retention of PVP-AgNPs and Ag(I) ions was positively correlated to clay and organic carbon (OC) contents as well as electrical conductivity (EC), pH, and cation exchange capacity (CEC) of the soils. Due to multicolinearity among the soil properties, principal component analysis (PCA) was used to group the soil properties which affect the retention of PVP-AgNPs and Ag(I) ions. Accordingly, we identified two groups of soil properties controlling retention of PVP-AgNPs and Ag(I) ions in the calcareous soils. The first group comprised soil solid phase parameters like clay, OC, and CEC, which generally control hetero-aggregation and adsorption reactions and the second group included soil solution variables such as EC and pH as well as Cl - and Ca 2+ concentrations, which are supposed to mainly affect homo-aggregation and precipitation reactions. Copyright © 2017. Published by Elsevier Ltd.

  5. Contrasting influence of soil nutrients and microbial community on differently sized basal consumers

    Science.gov (United States)

    Vonk, J. Arie; Mulder, Christian

    2013-07-01

    There is increasing evidence of the coexistence of trophic and environmental constraints belowground. While too often ignored in current literature, the extent to which phosphorus is relevant for soil biota was demonstrated in this study by positive correlations of soil C/P and N/P ratios with all the measured microbial parameters (biomass, density and activity), with the numerical abundance of roundworms (Nematoda) and potworms (Enchytraeidae) from lower trophic levels and with the roundworm biomass. Total worm biomass seems dependent on land use, being in rangelands about twice as high as in croplands, although the relative contribution of potworms remains comparable for both land use types (49 ± 20 % SD versus 45 ± 27 % SD). Besides soil [P], soil type plays an important role in the relative biomass of potworms compared to roundworms. Soil parameters (here pH, C/P and N/P ratios) are better predictors for the abundance and biomass of roundworms than microbial parameters. We also propose a graphical way to visualize the major responses of basal consumers to their microbial drivers.

  6. Role of traditional enclosures on the diversity of herbaceous vegetation in a semi-arid rangeland, southern Ethiopia

    OpenAIRE

    Angassa, A.; Oba, G.; Treydte, A.C.; Weladji, R. B.

    2010-01-01

    Grazing management and seasonality strongly influence the recovery potential of herbaceous vegetation in semi-arid rangelands of southern Ethiopia after history of heavy grazing. We investigated effects of management (enclosures versus grazed landscapes), age of enclosures and seasonality related to rainfall (i.e., independent variables) on herbaceous biomass, grass basal cover, herbaceous species abundance, species richness and diversity in a savanna rangeland of southern Ethiopia. We furthe...

  7. Soil type influences crop mineral composition in Malawi.

    Science.gov (United States)

    Joy, Edward J M; Broadley, Martin R; Young, Scott D; Black, Colin R; Chilimba, Allan D C; Ander, E Louise; Barlow, Thomas S; Watts, Michael J

    2015-02-01

    Food supply and composition data can be combined to estimate micronutrient intakes and deficiency risks among populations. These estimates can be improved by using local crop composition data that can capture environmental influences including soil type. This study aimed to provide spatially resolved crop composition data for Malawi, where information is currently limited. Six hundred and fifty-two plant samples, representing 97 edible food items, were sampled from >150 sites in Malawi between 2011 and 2013. Samples were analysed by ICP-MS for up to 58 elements, including the essential minerals calcium (Ca), copper (Cu), iron (Fe), magnesium (Mg), selenium (Se) and zinc (Zn). Maize grain Ca, Cu, Fe, Mg, Se and Zn concentrations were greater from plants grown on calcareous soils than those from the more widespread low-pH soils. Leafy vegetables from calcareous soils had elevated leaf Ca, Cu, Fe and Se concentrations, but lower Zn concentrations. Several foods were found to accumulate high levels of Se, including the leaves of Moringa, a crop not previously been reported in East African food composition data sets. New estimates of national dietary mineral supplies were obtained for non-calcareous and calcareous soils. High risks of Ca (100%), Se (100%) and Zn (57%) dietary deficiencies are likely on non-calcareous soils. Deficiency risks on calcareous soils are high for Ca (97%), but lower for Se (34%) and Zn (31%). Risks of Cu, Fe and Mg deficiencies appear to be low on the basis of dietary supply levels. Copyright © 2014. Published by Elsevier B.V.

  8. Rehabilitation of degraded rangelands: lessons learned

    Science.gov (United States)

    The introduction and subsequent invasion of cheatgrass (Bromus tectorum) has had astronomical effects to Great Basin rangelands. Cheatgrass has truncated secondary succession by outcompeting native plant species for limited resources, thus building persistent seed banks that take advantage of condi...

  9. Rangeland Ecology Monitoring Data : 1967-2013

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — The dataset describes rangeland monitoring results from the Hanksville, UT (USA) area. Monitoring results consist of canopy cover of plant species and functional...

  10. Influence of Different Slope Aspects on Some Soil Properties and Forest Soils Evolution (Case Study: Rostam Abad Region, Guilan Province)

    OpenAIRE

    M. Zarinibahador; - K. Nabiollahi; M. Norouzi

    2016-01-01

    Introduction: Spatial variation of soil properties is significantly influenced by numerous environmental factors such as landscape features, including position, topography, slope gradient and aspect, parent material, climate and vegetation. Soil properties vary spatially in south- and north-facing hill slopes. This factor (different slope aspects) can affect the distribution of soil organic matter, the presence or absence of a layer, pH, nutrient levels, soil mineralogical and micromorphologi...

  11. Bioremediation treatment of hydrocarbon-contaminated Arctic soils: influencing parameters.

    Science.gov (United States)

    Naseri, Masoud; Barabadi, Abbas; Barabady, Javad

    2014-10-01

    The Arctic environment is very vulnerable and sensitive to hydrocarbon pollutants. Soil bioremediation is attracting interest as a promising and cost-effective clean-up and soil decontamination technology in the Arctic regions. However, remoteness, lack of appropriate infrastructure, the harsh climatic conditions in the Arctic and some physical and chemical properties of Arctic soils may reduce the performance and limit the application of this technology. Therefore, understanding the weaknesses and bottlenecks in the treatment plans, identifying their associated hazards, and providing precautionary measures are essential to improve the overall efficiency and performance of a bioremediation strategy. The aim of this paper is to review the bioremediation techniques and strategies using microorganisms for treatment of hydrocarbon-contaminated Arctic soils. It takes account of Arctic operational conditions and discusses the factors influencing the performance of a bioremediation treatment plan. Preliminary hazard analysis is used as a technique to identify and assess the hazards that threaten the reliability and maintainability of a bioremediation treatment technology. Some key parameters with regard to the feasibility of the suggested preventive/corrective measures are described as well.

  12. Interspecific relationships among soil invertebrates influence pollutant effects of phenanthrene.

    Science.gov (United States)

    Cortet, Jérôme; Joffre, Richard; Elmholt, Susanne; Coeurdassier, Michael; Scheifler, Renaud; Krogh, Paul Henning

    2006-01-01

    Five mesofauna communities varying in both structure and composition were exposed to phenanthrene in mesocosms for up to four months. Effects of phenanthrene were assessed on mesofauna population dynamics, fungal biomass (ergosterol concentrations), and litter decomposition (litter mass loss, nitrogen concentration). The effects of each community on the fate of phenanthrene were also assessed. We hypothesize that phenanthrene affects the population dynamics of mesofauna and soil biological functioning depending on exposure duration, type of community, or both. Results show that phenanthrene exerted an effect on mesofauna and that the effects on some species, like Folsomia fimetaria, were influenced by the species composition in the mesocosms, the soil layer, and the sampling date. However, the effects of phenanthrene on ergosterol content and organic matter decomposition were not significantly influenced by community composition. These results demonstrate that interspecific relationships are needed to assess the toxicity of pollutants and should be taken into account in ecotoxicological risk assessment. Furthermore, this work does not support the hypothesis of a direct link between toxic effects of organic pollutants on mesofauna species and soil biological functioning.

  13. Using {sup 137}Cs measurements to investigate the influence of erosion and soil redistribution on soil properties

    Energy Technology Data Exchange (ETDEWEB)

    Du, P. [School of Geography, Beijing Normal University, Beijing (China); Geography, College of Life and Environmental Sciences, University of Exeter, Amory Building, Rennes Drive, Exeter, EX4 4RJ, Devon (United Kingdom); Walling, D.E., E-mail: d.e.walling@exeter.ac.u [Geography, College of Life and Environmental Sciences, University of Exeter, Amory Building, Rennes Drive, Exeter, EX4 4RJ, Devon (United Kingdom)

    2011-05-15

    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 {sup 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 {sup 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). {sup 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{sup -1} yr{sup -1} to a deposition rate of 19.2 t ha{sup -1} yr{sup -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

  14. Influence of nonlinear sorption kinetics on the slow-desorbing organic contaminant fraction in soil

    NARCIS (Netherlands)

    Schlebaum, W.; Schraa, G.; Riemsdijk, van W.H.

    1999-01-01

    Release rates of hydrophobic organic compounds (HOCs) from the soil matrix influence the availability of HOCs in soils or sediments for microbial degradation or removal by physical means (e.g., soil washing or soil venting). In this study it was shown that the initial contaminant concentration

  15. Measurement of soil lead bioavailability and influence of soil types and properties: A review.

    Science.gov (United States)

    Yan, Kaihong; Dong, Zhaomin; Wijayawardena, M A Ayanka; Liu, Yanju; Naidu, Ravi; Semple, Kirk

    2017-10-01

    Lead (Pb) is a widespread heavy metal which is harmful to human health, especially to young children. To provide a human health risk assessment that is more relevant to real conditions, Pb bioavailability in soils is increasingly employed in the assessment procedure. Both in vivo and in vitro measurements for lead bioavailability are available. In vivo models are time- consuming and expensive, while in vitro models are rapid, economic, reproducible, and reliable while involving more uncertainties. Uncertainties in various measurements create difficulties in accurately predicting Pb bioavailability, resulting in the unnecessary remediation of sites. In this critical review, we utilised available data from in vivo and in vitro studies to identify the key parameters influencing the in vitro measurements, and presented uncertainties existing in Pb bioavailability measurements. Soil type, properties and metal content are reported to influence lead bioavailability; however, the differences in methods for assessing bioavailability and the differences in Pb source limit one's ability to conduct statistical analyses on influences of soil factors on Pb bioavailability. The information provided in the review is fundamentally useful for the measurement of bioavailability and risk assessment practices. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Influence of microbiological soil-treatment preparations on selected properties of soil and its enzymatic activity in the conditions of replantation

    OpenAIRE

    Piotr Zydlik; Zofia Zydlik

    2016-01-01

    The research covered the influence of three microbiological preparations on the change of soil physico-chemical and biological parameters (activity of soil enzymes), as well as the contents of macro-components (N, P, K, Mg) in the conditions of a replant disease occurrence. Two types of soil were used in the experiment: soil used for 30 years in horticulture (replanted soil) and soil of optimum properties ready for horticultural planting (virgin soil). Both types of soil were treated with mic...

  17. Susceptibility of volcanic ash-influenced soil in northern Idaho to mechanical compaction

    Science.gov (United States)

    Deborah S. Page-Dumroese

    1993-01-01

    Timber harvesting and mechanical site preparation can reduce site productivity if they excessively disturb or compact the soil. Volcanic ash-influenced soils with low undisturbed bulk densities and rock content are particularly susceptible. This study evaluates the effects of harvesting and site preparation on changes in the bulk density of ash-influenced forest soils...

  18. Influence of soil and climate on root zone storage capacity

    Science.gov (United States)

    Euser, Tanja; McMillan, Hilary; Hrachowitz, Markus; Winsemius, Hessel; Savenije, Hubert

    2015-04-01

    The root zone water storage capacity (Sr) of a catchment is an important variable for the hydrological behaviour of a catchment; it strongly influences the storage, transpiration and runoff generation in an area. However, the root zone storage capacity is largely heterogeneous and not measurable. There are different theories about the variables affecting the root zone storage capacity; among the most debated are soil, vegetation and climate. The effect of vegetation and soil is often accounted for by detailed soil and land use maps. To investigate the effect of climate on the root zone storage capacity, an analogue can be made between the root zone storage capacity of a catchment and the human habit to design and construct reservoirs: both storage capacities help to overcome a dry period of a certain length. Humans often use the mass curve technique to determine the required storage needed to design the reservoir capacity. This mass curve technique can also be used to derive the root zone storage capacity created by vegetation in a certain ecosystem and climate (Gao et al., 2014). Only precipitation and discharge or evaporation data are required for this method. This study tests whether Sr values derived by both the mass curve technique and from soil maps are comparable for a range of catchments in New Zealand. Catchments are selected over a gradient of climates and land use. Special focus lies on how Sr values derived for a larger catchment are representative for smaller nested catchments. The spatial differences are examined between values derived from soil data and from climate and flow data. Gao, H., Hrachowitz, M., Schymanski, S.J., Fenicia, F., Sriwongsitanon, N., Savenije, H.H.G, (2014): Climate controls how ecosystems size the root zone storage capacity at catchment scale. DOI: 10.1002/2014GL061668

  19. Using rangeland health assessment to inform successional management

    Science.gov (United States)

    Rangeland health assessment provides qualitative information on ecosystem attributes. Successional management is a conceptual framework that allows managers to link information gathered in rangeland health assessment to ecological processes that need to be repaired to allow vegetation to change in ...

  20. Collaborative adaptive rangeland management fosters management-science partnerships

    Science.gov (United States)

    Rangelands of the western Great Plains of North America are complex social-ecological systems where management objectives for livestock production, grassland bird conservation and vegetation structure and composition converge. The Collaborative Adaptive Rangeland Management (CARM) experiment is a 10...

  1. Sorption of samarium in soils: influence of soil properties and Sm concentration

    Energy Technology Data Exchange (ETDEWEB)

    Ramirez-Guinart, Oriol; Salaberria, Aitor; Rigol, Anna; Vidal, Miquel [Analytical Chemistry department, Faculty of Chemistry, University of Barcelona, Marti i Franques 1-11, 08028, Barcelona (Spain)

    2014-07-01

    Due to the fact that barriers of Deep Geological Repositories (DGR) may lose efficiency before the radioisotopes present in the High Level Radioactive Waste (HLRW) completely decay, it is possible that, in the long-term, radioactive leachates may escape from the DGR and reach the soil and water compartments in the biosphere. Therefore, it is required to examine the interaction and mobility of radionuclides present in the HLRW, or their chemical analogues, to predict the impact of their eventual incorporation in the biosphere and to assess the derived risk. Although relevant data have been recently obtained for a few radionuclides in soils, there are still some important gaps for some radionuclides, such us for samarium (Sm). Sm is a lanthanide that, besides being considered as a natural analogue of actinides, may also be present in HLRW in the form of the radioactive isotope {sup 151}Sm. The main objective of this work was to obtain sorption data (K{sub d}) of {sup 151}Sm gathered from a set of soil samples physicochemical fully-characterized (pH, texture, cationic exchange capacity, soil solution cationic composition, organic matter, carbonate and metallic oxides content, etc.). Additionally, as an alternative for testing sorption capacity of radionuclides in soils is the use of the corresponding stable isotope or a chemical analogue, the influence of Sm concentration was also checked. To evaluate {sup 151}Sm sorption, batch assays were carried out for each soil sample, which consisted in a pre-equilibration step of 2 g of each soil with 50 ml of double deionised water, and a subsequent equilibration step with the same solution, but labelled with {sup 151}Sm. The activity of {sup 151}Sm in initial and final solutions was measured by liquid scintillation and K{sub d} ({sup 151}Sm) data were calculated. The reversibly sorbed fraction was estimated by the application of a single extraction test, with double deionised water, to soil residues coming from the previous

  2. Rangelands: Where Anthromes Meet Their Limits

    Directory of Open Access Journals (Sweden)

    Nathan F. Sayre

    2017-05-01

    Full Text Available Defining rangelands as anthromes enabled Ellis and Ramankutty (2008 to conclude that more than three-quarters of Earth’s land is anthropogenic; without rangelands, this figure would have been less than half. They classified all lands grazed by domestic livestock as rangelands, provided that human population densities were low; similar areas without livestock were excluded and classified instead as ‘wildlands’. This paper examines the empirical basis and conceptual assumptions of defining and categorizing rangelands in this fashion. Empirically, we conclude that a large proportion of rangelands, although used to varying degrees by domesticated livestock, are not altered significantly by this use, especially in arid, highly variable environments and in settings with long evolutionary histories of herbivory by wild animals. Even where changes have occurred, the dynamics and components of many rangelands remain structurally and functionally equivalent to those that preceded domestic livestock grazing or would be found in its absence. In much of Africa and Asia, grazing is so longstanding as to be inextricable from ‘natural’ or reference conditions for those sites. Thus, the extent of anthropogenic biomes is significantly overstated. Conceptually, rangelands reveal the dependence of the anthromes thesis on outdated assumptions of ecological climax and equilibrium. Coming to terms with rangelands—how they can be classified, understood, and managed sustainably—thus offers important lessons for understanding anthromes and the Anthropocene as a whole. At the root of these lessons, we argue, is not the question of human impacts on ecosystems but property relations among humans.

  3. Social and Economic Indicators of the Sustainable Rangelands Roundtable

    Science.gov (United States)

    John E. Mitchell; Daniel W. McCallum; Lewis E. Swanson; John Tanaka; Mark Brunson; Aaron Harp; L. Allen Torell; H. Theodore Heintz

    2006-01-01

    Social and economic systems provide a context and rationale for rangeland management. Sustaining rangeland ecosystems requires attention to the social and economic conditions that accompany the functioning of those systems. We present and discuss economic and social indicators for rangeland sustainability that have possible relevance in the United States. A brief...

  4. Indicators of rangeland health and functionality in the Intermountain West

    Science.gov (United States)

    Renee A. O' Brien; Curtis M. Johnson; Andrea M. Wilson; Van C. Elsbernd

    2003-01-01

    Rangelands comprise about 42 percent of the land area of the United States and provide vital land functions such as watershed, multiple-use, recreation, and other amenities. Currently, we do not know the status and trends of many of our nation's rangelands, and consistent protocols for describing rangeland system dynamics across land management agencies are...

  5. Influence of Inorganic Salts on Soils Liquid and Plastic Limits

    Directory of Open Access Journals (Sweden)

    Ayininuola, G.M.

    2013-01-01

    Full Text Available This study focused on the influence of inorganic salts on soil liquid limit (LL and plastic limit (PL. Sodium chloride, NaCl, potassium nitrate KNO3 and calcium sulphate, CaSO4 of various concentrations were added to two subsoils. Their liquid and plastic limits before and after contamination were monitored. Soil cation exchange capacity (CEC, exchangeable cations (sodium, Na+, potassium, K+, and calcium, Ca2+ and exchangeable anions (chloride, Cl-, nitrate, NO3, and sulphate, SO42- were determined. A set of equations for predicting LL and PL, (with R2 = 0.908 to 0.990 at different levels of chemical interaction with time was developed using multiple regression analysis model. The results showed that both NaCl and KNO3 brought about reduction in LL and PL while CaSO4 addition led to increment in LL and PL. The predictive equations revealed that there is high tendency for the contaminated soils to regain their uncontaminated LL and PL values with time.

  6. Use of small UAVs in rangeland sediment source area mapping

    Science.gov (United States)

    Kuhn, Nikolaus J.; Kuhn, Brigitte; Krenz, Juliane

    2017-04-01

    The occurrence of severe erosion features in rangelands is often seen as a sign of high sediment delivery from those areas into nearby waterbodies. However, runoff, erosion and sediment transport are often patchy and discontinuous and thus assuming a direct link between erosion features and sediment delivery can lead to serious over predictions. So far, available data on the size of erosion features and the movement of sediment was limited by the resolution of Digital Elevation Models, soil and vegetation maps. Small UAVs offer the opportunity to quantify both the loss of surface material associated with erosion features, such as rills, gullies and badlands, as well as an estimate of the volume of depositional features between the site of erosion and nearby waterbodies. This study presents the acquisition and use of UAV-derived topographic information aimed at assessing the relevance of badland-type features in rangeland catchments of the Great Karoo region in South Africa. In particular, the feasility to assess volumes of erosion and sediment deposits, as well as the potential pathways from source to sink area, and the change of connectivity over time, are discussed.

  7. Predictive Phenologic Modeling Using MODIS: A Tool for Rangeland Management

    Science.gov (United States)

    Kisen, N. M.; Hepner, G.; Hadley, H.

    2007-12-01

    Grazing is the predominant land use activity in the rangelands of the Inter-Mountain West. Vegetation phenology affects the impact of grazing; new plant growth is especially palatable to grazing animals. Over time, preferential grazing gives less palatable plants an advantage in rooting depth and may alter the composition of plant species and lead to soil erosion. The benefits of using remote spectral imagery to predict the onset and advancement of the phenologic phases for expansive and/or inaccessible areas is recognized, however, the practical application of this technology has been limited. A time series of Moderate Resolution Imaging Spectrometer (MODIS) vegetation indices was analyzed to identify the temporal profile of the growing season for surface vegetation in the Upper Colorado River Basin (UCRB). Drivers to which the progression of phenologic transition dates are most responsive were explored. Using phenological parameters defined from the MODIS time series and relationships of the phenological transition dates to the drivers, a predictive phenological model specific to the environmental parameters of the UCRB was developed. This model can be implemented at various spatial extents and temporal windows as part of a rangeland management strategy.

  8. Use of local pastoral species to increase fodder production of the saline rangelands in southern Tunisia

    Science.gov (United States)

    Tlili, Abderrazak; Tarhouni, Mohamed; Cardà, Artemi; Neffati, Mohamed

    2017-04-01

    Climate changes associated with multiple destructive human activities accelerate the degradation process of the natural rangelands around the world and especially the vulnerable areas such as the dryland ecosystems (Anaya-Romero et al., 2015; Eskandari et al., 2016; Muños Rojas et al., 2016; Vicente-Serrano et al., 2016). The vegetation cover and the biomass production of these ecosystems are decreasing and this is resulting in land degradation due to the soil erosion and changes in soil quality due to the abuse and misuse of the soil resources (Cerdà et al., 2016; Prosdocimi et al., 2016; Keesstra et al., 2016). To cope with such threats, it is necessary to develop some management techniques (restoration, plantation…) to enhance the biomass production and the carbon sequestration of the degraded rangelands (Muñoz-Rojas et al., 2016; Tarhouni et al., 2016). The valorization of saline water by planting pastoral halophyte species in salt-affected soils as well as the marginal areas are considered among the valuable tools to increase the rangeland production in dry areas. In this work, the ability of four plants (Atriplex halimus L. (Amaranthaceae), Atriplex mollis Desf. (Amaranthaceae), Lotus creticus L. (Fabaceae) and Cenchrus ciliaris L. (Poaceae)) to grow and to produce are tested under a field saline conditions (water and soil). Non-destructive method (Vegmeasure) is used to estimate the biomass production of these species. Chemical (crude protein, moisture and ash contents) and biochemical analyses (sugars, tannins and polyphenols contents) are also undertaken. Two years after plantation, the obtained results showed the ability of the four species to survive and to grow under high salinity degree. A strong positive correlation was obtained between the canopy cover and the dry biomass of the four studied species. Hence, the restoration of saline soils can be ensured by planting local halophytes. Acknowledgements. The research leading to these results has

  9. Carrying capacity in arid rangelands during droughts: the role of temporal and spatial thresholds.

    Science.gov (United States)

    Accatino, F; Ward, D; Wiegand, K; De Michele, C

    2017-02-01

    Assessing the carrying capacity is of primary importance in arid rangelands. This becomes even more important during droughts, when rangelands exhibit non-equilibrium dynamics, and the dynamics of livestock conditions and forage resource are decoupled. Carrying capacity is usually conceived as an equilibrium concept, that is, the consumer density that can co-exist in long-term equilibrium with the resource. As one of the first, here we address the concept of carrying capacity in systems, where there is no feedback between consumer and resource in a limited period of time. To this end, we developed an individual-based model describing the basic characteristics of a rangeland during a drought. The model represents a rangeland composed by a single water point and forage distributed all around, with livestock units moving from water to forage and vice versa, for eating and drinking. For each livestock unit we implemented an energy balance and we accounted for the gut-filling effect (i.e. only a limited amount of forage can be ingested per unit time). Our results showed that there is a temporal threshold above which livestock begin to experience energy deficit and burn fat reserves. We demonstrated that such a temporal threshold increases with the number of animals and decreases with the rangeland conditions (amount of forage). The temporal threshold corresponded to the time livestock take to consume all the forage within a certain distance from water, so that the livestock can return to water for drinking without spending more energy than they gain within a day. In this study, we highlight the importance of a time threshold in the assessment of carrying capacity in non-equilibrium conditions. Considering this time threshold could explain contrasting observations about the influence of livestock number on livestock conditions. In case of private rangelands, the herd size should be chosen so that the spatial threshold equals (or exceeds) the length of the drought.

  10. Monitoring Forage Production of California Rangeland Using Remote Sensing Observations

    Science.gov (United States)

    Liu, H.; Jin, Y.; Dahlgren, R. A.; O'Geen, A. T.; Roche, L. M.; Smith, A. M.; Flavell, D.

    2016-12-01

    Pastures and rangeland cover more than 10 million hectares in California's coastal and inland foothill regions, providing feeds to livestock and important ecosystem services. Forage production in California has a large year-to-year variation due to large inter-annual and seasonal variabilities in precipitation and temperature. It also varies spatially due to the variability in climate and soils. Our goal is to develop a robust and cost-effective tool to map the near-real-time and historical forage productivity in California using remote sensing observations from Landsat and MODIS satellites. We used a Monteith's eco-physiological plant growth theory: the aboveground net primary production (ANPP) is determined by (i) the absorbed photosynthetically active radiation (APAR) and the (ii) light use efficiency (LUE): ANPP = APAR * LUEmax * f(T) * f(SM), where LUEmax is the maximum LUE, and f(T) and f(SM) are the temperature and soil moisture constrains on LUE. APAR was estimated with Landsat and MODIS vegetation index (VI), and LUE was calibrated with a statewide point dataset of peak forage production measurements at 75 annual rangeland sites. A non-linear optimization was performed to derive maximum LUE and the parameters for temperature and soil moisture regulation on LUE by minimizing the differences between the estimated and measured ANPP. Our results showed the satellite-derived annual forage production estimates correlated well withcontemporaneous in-situ forage measurements and captured both the spatial and temporal productivity patterns of forage productivity well. This remote sensing algorithm can be further improved as new field measurements become available. This tool will have a great importance in maintaining a sustainable range industry by providing key knowledge for ranchers and the stakeholders to make managerial decisions.

  11. The influence of soil type and altered lignin biosynthesis on the physiology, growth and carbon allocation in Populus tremuloides

    Science.gov (United States)

    Jessica E. Hancock; Kate L. Bradley; Christian P. Giardina; Kurt S. Pregitzer

    2008-01-01

    Plants influence soil carbon (C) formation through the quality and quantity of C released to soil. Soil type, in turn can modify a plant's influence on soil through effects on plant production, tissue quality and regulation of soil C decomposition and stabilization. Wild-type aspen and three transgenic aspen lines expressing reduced stem lignin concentrations and/...

  12. Exploring differences of soil quality as related to management in ...

    African Journals Online (AJOL)

    soil, vegetation and biodiversity) and productivity. Vegetation condition in ... Keywords: chemical properties; enzyme activity; land-use management; microbial biomass; rangeland degradation; soil degradation. African Journal of Range ...

  13. Influence of temperature and organic matter content on soil respiration in a deciduous oak forest

    Directory of Open Access Journals (Sweden)

    Zsolt Kotroczó

    2014-12-01

    Full Text Available The increasing temperature enhances soil respiration differently depend on different conditions (soil moisture, soil organic matter, the activity of soil microbes. It is an essential factor to predicting the effect of climate change on soil respiration. In a temperate deciduous forest (North-Hungary we added or removal aboveground and belowground litter to determine total soil respiration. We investigated the relationship between total soil CO2 efflux, soil moisture and soil temperature. Soil CO2 efflux was measured at each plot using chamber based soil respiration measurements. We determined the temperature sensitivity of soil respiration. The effect of doubled litter was less than the effect of removal. We found that temperature was more influential in the control of soil respiration than soil moisture in litter removal treatments, particularly in the wetter root exclusion treatments (NR and NI (R2: 0.49-0.61. Soil moisture (R2: 0.18-0.24 and temperature (R2: 0.18-0.20 influenced soil respiration similarly in treatments, where soil was drier (Control, Double Litter, Double Wood. A significantly greater increase in temperature induced higher soil respiration were significantly higher (2-2.5-fold in root exclusion treatments, where soil was wetter throughout the year, than in control and litter addition treatments. The highest bacterial and fungal count was at the DL treatment but the differences is not significant compared to the Control. The bacterial number at the No Litter, No Root, No Input treatment was significantly lower at the Control. Similar phenomenon can be observed at the fungal too, but the differences are not significant. The results of soil respiration suggest that the soil aridity can reduce soil respiration increases with the temperature increase. Soil bacterial and fungal count results show the higher organic matter content and soil surface cover litter favors the activity.

  14. [Factors influencing the spatial variability in soil respiration under different land use regimes].

    Science.gov (United States)

    Chen, Shu-Tao; Liu, Qiao-Hui; Hu, Zheng-Hua; Liu, Yan; Ren, Jing-Quan; Xie, Wei

    2013-03-01

    In order to investigate the factors influencing the spatial variability in soil respiration under different land use regimes, field experiments were performed. Soil respiration and relevant environment, vegetation and soil factors were measured. The spatial variability in soil respiration and the relationship between soil respiration and these measured factors were investigated. Results indicated that land use regimes had significant effects on soil respiration. Soil respiration varied significantly (P Soil respiration rates ranged from 1.82 to 7.46 micromol x (m2 x s)(-1), with a difference of 5.62 micromol x (m2 x s)(-1) between the highest and lowest respiration rates. Soil organic carbon was a key factor controlling the spatial variability in soil respiration. In all, ecosystems studied, the relationship between soil respiration and soil organic carbon content can be described by a power function. Soil respiration increased with the increase of soil organic carbon. In forest ecosystem, the relationship between soil respiration and diameter at breast height (DBH) of trees can be explained by a natural logarithmic function. A model composed of soil organic carbon (C, %), available phosphorous (AP, g x kg(-1)) and diameter at breast height (DBH, cm) explained 92.8% spatial variability in soil respiration for forest ecosystems.

  15. The influence of organic matter on sorption and fate of glyphosate in soil - Comparing different soils and humic substances

    Energy Technology Data Exchange (ETDEWEB)

    Albers, Christian N., E-mail: calbers@ruc.d [Dept. of Geochemistry, Geological Survey of Denmark and Greenland, DK-1350 Copenhagen (Denmark); Dept. of Science, Systems and Models, Roskilde University, DK-4000 Roskilde (Denmark); Banta, Gary T. [Dept. of Environmental, Social and Spatial Change, Roskilde University, DK-4000 Roskilde (Denmark); Hansen, Poul Erik [Dept. of Science, Systems and Models, Roskilde University, DK-4000 Roskilde (Denmark); Jacobsen, Ole S. [Dept. of Geochemistry, Geological Survey of Denmark and Greenland, DK-1350 Copenhagen (Denmark)

    2009-10-15

    Soil organic matter (SOM) is generally believed not to influence the sorption of glyphosate in soil. To get a closer look on the dynamics between glyphosate and SOM, we used three approaches: I. Sorption studies with seven purified soil humic fractions showed that these could sorb glyphosate and that the aromatic content, possibly phenolic groups, seems to aid the sorption. II. Sorption studies with six whole soils and with SOM removed showed that several soil parameters including SOM are responsible for the strong sorption of glyphosate in soils. III. After an 80 day fate experiment, approx40% of the added glyphosate was associated with the humic and fulvic acid fractions in the sandy soils, while this was the case for only approx10% of the added glyphosate in the clayey soils. Glyphosate sorbed to humic substances in the natural soils seemed to be easier desorbed than glyphosate sorbed to amorphous Fe/Al-oxides. - Glyphosate was sorbed by purified humic substances and a significant amount of glyphosate was found to be associated with soil organic matter in whole soils.

  16. Insights into the Carbon Sequestration Potential of Rangelands Through Measurement and Modeling of Differently Managed Pastures

    Science.gov (United States)

    Owen, J. J.; Hartman, M.; Parton, W. J.; Silver, W. L.

    2014-12-01

    Poor management of rangelands has led to significant soil organic matter losses globally, and contributed to increasing atmospheric CO2 concentrations. Restoring and increasing soil carbon (C) content in rangelands offers an opportunity to mitigate climate change while improving soil conditions and increasing forage production. Organic matter amendments are used to improve soil properties, but predicting the resulting changes in soil C is challenging due to the interactions between amendment characteristics, climate, and soil characteristics. We used data from 10 pasture-based dairies in California and the DayCent model to test the impact of long-term (>30 year) manure additions on soil C pools and fluxes. Soils were sampled from 26 fields which had solid, liquid, solid and liquid, or no manure additions. These field data and management information provided by the ranchers were used to model the effects of manure amends on soil C storage and loss. Soil C was significantly greater in manured fields than non-manured fields when corrected for clay content and slope. Fields with higher clay had more soil C, as did those with lower slopes, and these effects were large enough to confound the manuring effect. DayCent was able to accurately estimate total soil C when parameterized with field-specific management practices, averaging only a 10±1% difference between measurement and modeled values. Using generalized management histories for manured and non-manured fields, as would be used for regional-scale estimates, produced less accurate results with a 24±3% average difference between measurement and modeled values. Modeling alternate scenarios for each field suggested that manure amendment increased soil C and forage production by 0.6 Mg ha-1 y-1 and 0.3 Mg ha-1 y-1, respectively. Forecasting to 2100 showed that in manure-amended fields, soil C increased until 2080 before stabilization, mostly through gains in the pool with slow turnover. The "passive soil C" pool

  17. The influences of four types of soil on the growth, physiological and biochemical characteristics of Lycoris aurea (L’ Her.) Herb

    OpenAIRE

    Miaohua Quan; Juan Liang

    2017-01-01

    Based on the characteristics of Lycoris aurea (L. aurea) natural distribution and local soil types, we selected four representative types of soil, including humus soil, sandy soil, garden soil and yellow-brown soil, for conducting the cultivation experiments to investigate key soil factors influencing its growth and development and to select the soil types suitable for cultivating it. We found that there existed significant differences in the contents of mineral elements and the activities of...

  18. Influence of olive oil mill waste amendment on fate of oxyfluorfen in Southern Spain soils

    Science.gov (United States)

    The influence of olive oil mill waste (OOMW) amendment on soil processes affecting the herbicide oxyfluorfen (2-chloro-4-trifluoromethylphenyl-3-ethoxy-4-nitrophenyl ether) in two soils (P2 and SJ) was assessed under laboratory conditions. The soils used were from two diverse locations in Guadalqui...

  19. Influence of soil and management of maize ( Zea mays L.) yield in ...

    African Journals Online (AJOL)

    The reliability of soil classification at the series level as a basis for crop yield prediction was examined by comparing the influence of cultural management and soil classification on the yield of maize. Yield of maize was measured on different soil series for some selected farms for two years using two management systems ...

  20. Influence of soil structure on contaminant leaching from injected slurry

    DEFF Research Database (Denmark)

    Amin, M. G. Mostofa; Pedersen, Christina Østerballe; Forslund, Anita

    2016-01-01

    of water through the macropore flow path in the intact soil. Estrogen leached from the intact soil in the first event only, but for the disturbed soil it was detected in the leachates of last two events also. Leaching from the later events was attributed to higher colloid transport from the disturbed soils...... macropore flow paths. The slurry constituents that ended up in or near the macropore flow paths of the intact soil were presumably washed out relatively quickly in the first event. For the last three events the intact soil leached fewer microorganisms than the disturbed soil due to the bypassing effect...

  1. Evaluación del modelo WEPP para predecir la erosión hídrica en pastizales semiáridos del noreste de la Patagonia Evaluation of the WEPP model to predict soil erosion in northeastern Patagonian rangelands

    Directory of Open Access Journals (Sweden)

    Marcelo P Chartier

    2010-07-01

    Full Text Available Los modelos matemáticos son herramientas útiles para la predicción de las pérdidas de suelo por erosión hídrica. El desarrollo reciente del modelo WEPP y su utilización para evaluar los riesgos de erosión en pastizales naturales ha significado un avance interesante en el campo de la erosión y la conservación de suelos de estos ecosistemas. En este trabajo examinamos la eficiencia del modelo WEPP para predecir los procesos hidrológicos y de erosión del suelo en los pastizales naturales semiáridos del noreste de la provincia de Chubut. Se identificaron tres comunidades de plantas ubicadas a lo largo de un gradiente de degradación del suelo: estepa herbácea con arbustos aislados (EH, estepa herbáceo-arbustiva (EHA y estepa arbustiva degradada (EA. En cada una de estas comunidades se aplicó una lluvia simulada (100 mm h-1 durante 30 min sobre parcelas de 1 m² (0,6 x 1,67 m y se colectó el escurrimiento y los sedimentos totales. A partir de los datos de la condición superficial de cada parcela se estimó el escurrimiento y la producción de sedimentos mediante el modelo WEPP. En este trabajo se observó una baja eficiencia del modelo WEPP para predecir el escurrimiento (Eficiencia, E = 0,14 y la erosión del suelo (E = -0,93. La predicción del escurrimiento y pérdida de suelo del modelo WEPP mostró mayor sensibilidad a cambios en los parámetros de lluvia y pendiente del terreno y una sensibilidad moderada a cambios en la cobertura, textura, erodabilidad del suelo y conductividad hidráulica efectiva. El escurrimiento y la producción de sedimentos estimados por WEPP fueron significativamente diferentes en las distintas comunidades de plantas (p Mathematical models are useful tools to predict soil loss by water erosion. The recent development of the WEPP model and its use in assessing the risks of erosion in rangelands has led to significant advances in the field of erosion and soil conservation of these ecosystems. In this

  2. Influence of salinity and water content on soil microorganisms

    OpenAIRE

    Nan Yan; Petra Marschner; Wenhong Cao; Changqing Zuo; Wei Qin

    2015-01-01

    Salinization is one of the most serious land degradation problems facing world. Salinity results in poor plant growth and low soil microbial activity due to osmotic stress and toxic ions. Soil microorganisms play a pivotal role in soils through mineralization of organic matter into plant available nutrients. Therefore it is important to maintain high microbial activity in soils. Salinity tolerant soil microbes counteract osmotic stress by synthesizing osmolytes which allows them to maintain t...

  3. INFLUENCE OF DIFFERENT SOIL TILLAGE VARIANTS ON QUALITY OF SEED DISTRIBUTION QUALITY PER SURFACE AND DEPTH

    Directory of Open Access Journals (Sweden)

    Luka Šumanovac

    2000-12-01

    Full Text Available The paper aims to present influence of different soil tillage variants on quality of seed distribution per surface and depth. A sowing experiment was set up in three soil tillage variants: a repeated disking, b conventional tillage, c ploughing + harrowing. Soil levelling, effects of longitudinal and transverzal distribution as well as seed distribution per depth were analyzed by the investigation. The research results indicate the fact that no soil tillage variant is characterized by achieving satisfactory sowing quality . It means that reduced soil tillage application is justifiable in terms of energetic aspect, work productivity increase, sowing performance in optimal agricultural terms etc., compared to conventional soil tillage.

  4. INFLUENCE OF SOIL CHEMICAL AND PHYSICAL PROPERTIES ON OCURRENCE OF TRICHODERMA SPP. IN EMBU, KENYA

    Directory of Open Access Journals (Sweden)

    Sheila A. Okoth

    2009-10-01

    Full Text Available Soil samples were collected from 8 land use types in Embu to study the effects of land use on soil chemical and physical parameters and on the occurrence of Trichoderma spp. The fungus was recovered from the soil using the dilution plate and soil washing technique. The remaining soil samples were used to measure the following characters of the soil; pH was determined in 1:1 (w/v soil – water suspension with pH meter, total nitrogen was determined by the Kjeldahl method, available nutrients P, K, Na, Ca and Mg were determined using Mehlich method while total organic carbon was determined by calorimetric method. Land use type (LUT, plant cover, and soil physical and chemical properties influenced Trichoderma occurrence. The frequency of isolation of Trichoderma spp. was highest in napier LUT followed by indigenous forests. Carbon, N, Mg and Fe loaded with forest land use type suggesting their influence on fungal diversity in this LUT. The forests had clay loam soils with higher porosity and water retention capacity compared with the cultivated LUTs which were characterized with clay soils and bulk density. Napier together with other cultivated LUTs which had low records of the fungus loaded positively with Mn and Cu. This implied that plant type was the major determining factor for the high population of Trichoderma recorded in napier LUT. The diversity of soil factors observed in the fallow lands explained the influence of land management on soil physical and chemical characteristics which in turn determined the fungal distribution. Soil depth (0-20cm did not influence soil factors though fungal diversity, abundance and evenness varied with depth suggesting the influence of other drivers.This study explains the fact that many factors interact in determining the occurrence of Trichoderma spp. and that in some situations it is the soil that is the key factor determining fungal occurrence and diversity while in others it is the plant type.

  5. Rehabilitation of cheatgrass-infested rangelands: management

    Science.gov (United States)

    This is the final part of a three part series specifically addressing lessons learned concerning the management of rehabilitated cheatgrass-infested rangelands. Steve Novak and Richard Mack reported in 2003 that they found no evidence of outcrossing in 2,000 cheatgrass seedlings from 60 North Americ...

  6. Rehabilitation of cheatgrass-infested rangelands: concepts

    Science.gov (United States)

    The introduction and subsequent invasion of cheatgrass (Bromus tectorum) onto millions of acres of Intermountain West rangelands has caused astronomical changes to numerous ecosystems and the multiple uses that depend on healthy and functional ecosystems. This is the first part, of a 3-part series ...

  7. Managing the livestock– Wildlife interface on rangelands

    Science.gov (United States)

    du Toit, Johan T.; Cross, Paul C.; Valeix, Marion

    2017-01-01

    On rangelands the livestock–wildlife interface is mostly characterized by management actions aimed at controlling problems associated with competition, disease, and depredation. Wildlife communities (especially the large vertebrate species) are typically incompatible with agricultural development because the opportunity costs of wildlife conservation are unaffordable except in arid and semi-arid regions. Ecological factors including the provision of supplementary food and water for livestock, together with the persecution of large predators, result in livestock replacing wildlife at biomass densities far exceeding those of indigenous ungulates. Diseases are difficult to eradicate from free-ranging wildlife populations and so veterinary controls usually focus on separating commercial livestock herds from wildlife. Persecution of large carnivores due to their depredation of livestock has caused the virtual eradication of apex predators from most rangelands. However, recent research points to a broad range of solutions to reduce conflict at the livestock–wildlife interface. Conserving wildlife bolsters the adaptive capacity of a rangeland by providing stakeholders with options for dealing with environmental change. This is contingent upon local communities being empowered to benefit directly from their wildlife resources within a management framework that integrates land-use sectors at the landscape scale. As rangelands undergo irreversible changes caused by species invasions and climate forcings, the future perspective favors a proactive shift in attitude towards the livestock–wildlife interface, from problem control to asset management.

  8. Management of Collective Rangelands in Rhamna (Morocco ...

    International Development Research Centre (IDRC) Digital Library (Canada)

    Rangelands are severely degraded in Morocco. This has stimulated public interventions to reduce the pressure on natural resources and promote sustainable management. In Rhamna, a region traditionally used for transhumance, such efforts have met with limited success because they have not taken into consideration ...

  9. Increasing flexibility in rangeland management during drought

    Science.gov (United States)

    The extreme drought that began in 2011 and persists throughout the central and western US presents a challenge to sustainable rangeland management. Wyoming ranchers manage half of this drought-prone state and are at the forefront of this challenge. We examined Wyoming ranchers’ drought management st...

  10. Soil nutrients influence growth response of temperate tree species to drought

    OpenAIRE

    Levesque Mathieu; Walthert Lorenz; Weber Pascale

    2016-01-01

    1. Soil properties can buffer forest response to global climate change. However it is unclear how soil characteristics water availability and their interactions can affect drought response of trees. The aim of this study was to assess the influence of soil nutrients and physical soil properties on the growth sensitivity of Fagus sylvatica Quercus spp. Fraxinus excelsior Abies alba Picea abies and Pinus sylvestris to drought in Central Europe. 2. Yearly growth data from increment cores were o...

  11. Growth and extracellular phosphatase activity of arbuscular mycorrhizal hyphae as influenced by soil organic matter

    DEFF Research Database (Denmark)

    Joner, E.J.; Jakobsen, I.

    1995-01-01

    precipitation leached through the soil, or indoor at constant moisture) with or without 9% (w/w) chopped wheat straw plus mineral N. Then the soils were partially sterilized and placed in two-compartment pots where mycorrhizal or non-mycorrhizal cucumber plants were grown in one root compartment (RC), and soils...... have influenced alkaline phosphatase excreted by other microorganisms, probably through competition for nutrients. Phosphatase activity was not correlated with the concentration of labile organic P in soil extracts....

  12. Influence of soil pH and fertilization on the dry matter production ...

    African Journals Online (AJOL)

    Reports the results of a study conducted to evaluate the influence of soil pH and fertilization on the dry matter production, chemical composition and organic matter digestibility of Panicum maximum; The influence of soil pH and fertilization (N, P and Zn) on the dry matter (DM) production, chemical composition (crude protein, ...

  13. Influence of Organic Manuring on the Post Harvest Soil Quality of ...

    African Journals Online (AJOL)

    These characters depend on the supplement provided to the soil in terms of organic and inorganic amendments. It also reflects the soil fertility status which has a high influence on the production of crops. Applications of organic ingredients like composts, vermicomposts and other organic sources have an influence on the ...

  14. Conservation Tillage influence on soil carbon and aggregation in semiarid rainfed agriculture (SW Spain)

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-Garrido, R.; Lopez, M. V.; Madejon, E.; Moreno, F.; Murillo, J. M.

    2009-07-01

    Soil aggregation has a strong influence on soil physical properties. The aim of this study was to determine the influence of two tillage systems, traditional tillage and conservation tillage, on soil aggregate size distribution and water aggregate stability. Two experiments were established: a long-term experiment (15 years), in which traditional tillage (TT{sub 1}5) and reduced tillage (RT15) were compared. (Author)

  15. Laboratory assessment of the influence of the proportion of waste foundry sand on the geotechnical engineering properties of clayey soils

    CSIR Research Space (South Africa)

    Mgangira, Martin B

    2006-01-01

    Full Text Available Soil improvement can be achieved through mechanical stabilisation using industrial byproducts. Clayey soils were blended with waste foundry sand to examine its influence on the geotechnical engineering properties of the soils. The waste foundry sand...

  16. The influence of different soil management practices on auxin herbicide interactions with organic carbon in soil aggregate fractions

    Science.gov (United States)

    Schnitzler, Frauke; Haupt, Nadine; Burauel, Peter; Berns, Anne E.

    2010-05-01

    The influence of changing organic carbon contents in soils on the sorption and/or sequestration mechanisms of xenobiotics and their bioavailability are still not understood precisely. The present work discusses the turnover of a crop residue interacting with processes like mobilisation, binding and metabolism of an auxin herbicide in soil. The soil type was a haplic chernozem, available in three crop production regimes (low, normal and high) due to three types of fertilisation (none, mineral and mineral & organic) [1]. Two sets of experiments were conducted with undisturbed soil columns under field-like conditions. In the first set 14C-labelled maize straw was incorporated into the top soil and after three months incubation the herbicide benazolin was applied. In the second set the unlabelled maize straw was incorporated first, then 14C-labelled benazolin was added. Soil layers of 0-5 cm and 5-10 cm were fractionated in according to a soil aggregate fractionation procedure [2]. The content of organic carbon and the distribution of benazolin and its metabolites were detected in the gained soil fractions. In general, the specific organic carbon content and the specific 14C-activity of benazolin and its metabolites increased in the order from sand-sized though silt-sized to clay fraction due to increasing specific surface areas and sorption sites of the mineral particles. The highest sorption capacity of benazolin and its metabolites was detected in the soil layers of 0-5 cm with mineral fertilisation. In the 5-10 cm soil layers the binding capacity increased with increasing crop production. It was shown that more than half of the residual 14C-activity was not extractable. LC-MS/MS analysis of the extracts showed that the major components were benazolin and the relatively non-mobile thiazolin. The amount of benazolin in the extracts increased with increasing crop production, but decreased with increasing soil depth. These results indicate that maize straw amendment

  17. Research Note Detecting the onset of rangeland degradation using ...

    African Journals Online (AJOL)

    Mean annual soil respiration correlates with net primary productivity and therefore provides an indication of ecosystem functioning. Soil respiration, however, varies considerably in space and time owing to the influence of factors such as soil nutrient content, temperature and water content. Comparing soil respiration across ...

  18. Quantification of the inevitable: the influence of soil macrofauna on soil water movement in rehabilitated open-cut mined lands

    Science.gov (United States)

    Arnold, S.; Williams, E. R.

    2016-01-01

    Recolonisation of soil by macrofauna (especially ants, termites and earthworms) in rehabilitated open-cut mine sites is inevitable and, in terms of habitat restoration and function, typically of great value. In these highly disturbed landscapes, soil invertebrates play a major role in soil development (macropore configuration, nutrient cycling, bioturbation, etc.) and can influence hydrological processes such as infiltration, seepage, runoff generation and soil erosion. Understanding and quantifying these ecosystem processes is important in rehabilitation design, establishment and subsequent management to ensure progress to the desired end goal, especially in waste cover systems designed to prevent water reaching and transporting underlying hazardous waste materials. However, the soil macrofauna is typically overlooked during hydrological modelling, possibly due to uncertainties on the extent of their influence, which can lead to failure of waste cover systems or rehabilitation activities. We propose that scientific experiments under controlled conditions and field trials on post-mining lands are required to quantify (i) macrofauna-soil structure interactions, (ii) functional dynamics of macrofauna taxa, and (iii) their effects on macrofauna and soil development over time. Such knowledge would provide crucial information for soil water models, which would increase confidence in mine waste cover design recommendations and eventually lead to higher likelihood of rehabilitation success of open-cut mining land.

  19. Influence of Elevation Data Resolution on Spatial Prediction of Colluvial Soils in a Luvisol Region.

    Directory of Open Access Journals (Sweden)

    Vít Penížek

    Full Text Available The development of a soil cover is a dynamic process. Soil cover can be altered within a few decades, which requires updating of the legacy soil maps. Soil erosion is one of the most important processes quickly altering soil cover on agriculture land. Colluvial soils develop in concave parts of the landscape as a consequence of sedimentation of eroded material. Colluvial soils are recognised as important soil units because they are a vast sink of soil organic carbon. Terrain derivatives became an important tool in digital soil mapping and are among the most popular auxiliary data used for quantitative spatial prediction. Prediction success rates are often directly dependent on raster resolution. In our study, we tested how raster resolution (1, 2, 3, 5, 10, 20 and 30 meters influences spatial prediction of colluvial soils. Terrain derivatives (altitude, slope, plane curvature, topographic position index, LS factor and convergence index were calculated for the given raster resolutions. Four models were applied (boosted tree, neural network, random forest and Classification/Regression Tree to spatially predict the soil cover over a 77 ha large study plot. Models training and validation was based on 111 soil profiles surveyed on a regular sampling grid. Moreover, the predicted real extent and shape of the colluvial soil area was examined. In general, no clear trend in the accuracy prediction was found without the given raster resolution range. Higher maximum prediction accuracy for colluvial soil, compared to prediction accuracy of total soil cover of the study plot, can be explained by the choice of terrain derivatives that were best for Colluvial soils differentiation from other soil units. Regarding the character of the predicted Colluvial soils area, maps of 2 to 10 m resolution provided reasonable delineation of the colluvial soil as part of the cover over the study area.

  20. Influence of Elevation Data Resolution on Spatial Prediction of Colluvial Soils in a Luvisol Region

    Science.gov (United States)

    Penížek, Vít; Zádorová, Tereza; Kodešová, Radka; Vaněk, Aleš

    2016-01-01

    The development of a soil cover is a dynamic process. Soil cover can be altered within a few decades, which requires updating of the legacy soil maps. Soil erosion is one of the most important processes quickly altering soil cover on agriculture land. Colluvial soils develop in concave parts of the landscape as a consequence of sedimentation of eroded material. Colluvial soils are recognised as important soil units because they are a vast sink of soil organic carbon. Terrain derivatives became an important tool in digital soil mapping and are among the most popular auxiliary data used for quantitative spatial prediction. Prediction success rates are often directly dependent on raster resolution. In our study, we tested how raster resolution (1, 2, 3, 5, 10, 20 and 30 meters) influences spatial prediction of colluvial soils. Terrain derivatives (altitude, slope, plane curvature, topographic position index, LS factor and convergence index) were calculated for the given raster resolutions. Four models were applied (boosted tree, neural network, random forest and Classification/Regression Tree) to spatially predict the soil cover over a 77 ha large study plot. Models training and validation was based on 111 soil profiles surveyed on a regular sampling grid. Moreover, the predicted real extent and shape of the colluvial soil area was examined. In general, no clear trend in the accuracy prediction was found without the given raster resolution range. Higher maximum prediction accuracy for colluvial soil, compared to prediction accuracy of total soil cover of the study plot, can be explained by the choice of terrain derivatives that were best for Colluvial soils differentiation from other soil units. Regarding the character of the predicted Colluvial soils area, maps of 2 to 10 m resolution provided reasonable delineation of the colluvial soil as part of the cover over the study area. PMID:27846230

  1. A spatial dynamic model to assess piospheric land degradation processes of SW Iberian rangelands

    Science.gov (United States)

    Herguido Sevillano, Estela; Ibáñez, Javier; Francisco Lavado Contador, Joaquín; Pulido-Fernández, Manuel; Schnabel, Susanne

    2015-04-01

    Iberian open wooded rangelands (known as dehesas or montados) constitute valuable agro-silvo-pastoral systems traditionally considered as highly sustainable. Nevertheless, in the recent decades, those systems are undergoing changes of land use and management practices that compromise its sustainability. Some of those changes, as the rising construction of watering points and the high spatial fragmentation and livestock movement restriction associated to fencing, show an aggregated effect with livestock, producing an impact gradient over soil and vegetation. Soil compaction related to livestock pressure is higher around watering points, with bare soil halos and patches of scarce vegetation or nude soil developing with higher frequency in areas close to them. Using the freeware Dinamica EGO as environmental modeling platform, we have developed a theoretic spatial dynamic model that represents some of the processes of land degradation associated to livestock grazing in dehesa fenced enclosures. Spatial resolution is high since every cell in the model is a square unit area of 1 m2. We paid particular attention to the relationships between soil degradation by compaction (porosity), livestock pressure, rainfall, pasture growth and shrub cover and bare soil generation. The model considers pasture growth as related to soil compaction, measured by the pore space in the top 10 cm soil layer. Annual precipitation is randomly generated following a normal distribution. When annual precipitation and pore space increase, also does pasture growth. Besides, there is a feedback between pasture growth and pore space, given that pasture roots increases soil porosity. The cell utility for livestock function has been defined as an exponential function of the distance of a cell to watering points and the amount of pasture present in it. The closer the cell to a pond and the higher the amount of pasture, the higher is cell utility. The latter is modulated by a normal random variable to

  2. Biosolids Effects in Chihuahuan Desert Rangelands: A Ten-Year Study

    Directory of Open Access Journals (Sweden)

    David B. Wester

    2011-01-01

    Full Text Available Arid and semiarid rangelands are suitable for responsible biosolids application. Topical application is critical to avoid soil and vegetation disturbance. Surface-applied biosolids have long-lasting effects in these ecosystems. We conducted a 10-year research program investigating effects of biosolids applied at rates from 0 to 90 dry Mg ha−1 on soil water infiltration; runoff and leachate water quality; soil erosion; forage production and quality; seedling establishment; plant physiological responses; nitrogen dynamics; biosolids decomposition; and grazing animal behavior and management. Biosolids increased soil water infiltration and reduced erosion. Effects on soil water quality were observed only at the highest application rates. Biosolids increased soil nitrate-nitrogen. Biosolids increased forage production and improved forage quality. Biosolids increased leaf area of grasses; photosynthetic rates were not necessarily increased by biosolids. Biosolids effects on plant establishment are expected only under moderately favorable conditions. Over an 82-mo exposure period, total organic carbon, nitrogen, and total and available phosphorus decreased and inorganic matter increased. Grazing animals spent more time grazing, ruminating, and resting in biosolids-treated areas; positive effects on average daily gain were observed during periods of higher rainfall. Our results suggest that annual biosolids application rates of up to 18 Mg ha−1 are appropriate for desert rangelands.

  3. Investigation of Irrigation Influence by Domestic Wastewater on Soil Characteristics

    OpenAIRE

    Fayaz Aghayari; Hossein Hassanpour Darvishi

    2012-01-01

    To investigate the beneficial impacts of wastewater on soil properties, we conducted an experiment in the lysimeter by measuring certain features essentially related to soil characteristics. Our objectives in this study were (i) the wastewater infiltration by soil and (ii) the effect of wastewater on soil properties. In this experiment, 9 lysimeter were used, 1, 2 and 3 lysimeters irrigated by domestic wastewater. Then, first drainage water accumulated from these lysimeters and 4, 5 and 6 lys...

  4. Influence of Parent Material and Topography on some Soil ...

    African Journals Online (AJOL)

    Differences among topographic positions reflected soil properties that are typically associated with bio and geochemical processes (weathering and leaching). Parent material × topography interaction was significant (p<0.05) for Fe. With respect to chemical soil fertility, soils developed on banded gneiss and quartzite schist ...

  5. Neighborhood size of training data influences soil map disaggregation

    Science.gov (United States)

    Soil class mapping relies on the ability of sample locations to represent portions of the landscape with similar soil types; however, most digital soil mapping (DSM) approaches intersect sample locations with one raster pixel per covariate layer regardless of pixel size. This approach does not take ...

  6. The influence of organic mulches on soil temperatures with the ...

    African Journals Online (AJOL)

    Fine-seeded grasses are established with great difficulty, especially on heavy clay soil, but the literature suggests that organic mulches may counteract constraining soil factors which result in poor germination. Various organic mulches were used in this study in order to determine the effect of soil temperature on ...

  7. Influence of salinity and water content on soil microorganisms

    Directory of Open Access Journals (Sweden)

    Nan Yan

    2015-12-01

    Full Text Available Salinization is one of the most serious land degradation problems facing world. Salinity results in poor plant growth and low soil microbial activity due to osmotic stress and toxic ions. Soil microorganisms play a pivotal role in soils through mineralization of organic matter into plant available nutrients. Therefore it is important to maintain high microbial activity in soils. Salinity tolerant soil microbes counteract osmotic stress by synthesizing osmolytes which allows them to maintain their cell turgor and metabolism. Osmotic potential is a function of the salt concentration in the soil solution and therefore affected by both salinity (measured as electrical conductivity at a certain water content and soil water content. Soil salinity and water content vary in time and space. Understanding the effect of changes in salinity and water content on soil microorganisms is important for crop production, sustainable land use and rehabilitation of saline soils. In this review, the effects of soil salinity and water content on microbes are discussed to guide future research into management of saline soils.

  8. Influence of salinity on soil chemical properties and surrounding ...

    African Journals Online (AJOL)

    Akomolafe Gbenga

    2013-11-14

    Nov 14, 2013 ... samples were collected randomly from the salt mining site and 10 m away from the site (control) at 5, ... Salt-affected soils, as they are called, are either saline or sodic. Saline soils refer to soils with electrical conductivity above 4. dS/m and usually ... Brock, 2001; USDA, Natural Resources Conservation.

  9. Rangeland Rummy - a board game to support adaptive management of rangeland-based livestock systems.

    Science.gov (United States)

    Farrié, B; Jouven, M; Launay, F; Moreau, J-C; Moulin, C-H; Piquet, M; Taverne, M; Tchakérian, E; Thénard, V; Martin, G

    2015-01-01

    Rangeland-based livestock systems have to deal with the significant instability and uncertainty of the agricultural context (policy changes, volatility of input prices, etc.), and especially of the climatic context. Thus, they are particularly concerned by adaptive management strategies. To support the development of such strategies, we developed a board game including a computer model called "Rangeland Rummy". It is to be used by groups of farmers and agricultural consultants in the context of short workshops (about 3 h). Rangeland Rummy builds upon five types of material object: (i) a game board; (ii) a calendar stick indicating the starting date of the game board; (iii) sticks marked with the feed resources available for combinations of vegetation types and their management practices; (iv) cards to define animal groups and their feeding requirements throughout the year; (v) cards related to types of feed that can be attributed to animal groups throughout the year. Using these material objects, farmers collectively design a rangeland-based livestock system. This system is immediately evaluated using a computer model, i.e. a spreadsheet providing graphs and indicators providing information on, among other things, the extent to which quantitative and qualitative animal feeding requirements are covered across the year. Playing the game thus consists in collectively and iteratively designing and evaluating rangeland-based livestock systems, while confronting the players with new contextual challenges (e.g. interannual variability of weather, volatility of input prices) or new farmers' objectives (e.g. being self-sufficient for animal feeding). An example of application of Rangeland Rummy with 3 farmers in southern France is reported. Applications show that it tends to develop farmers' adaptive capacity by stimulating their discussions and the exchange of locally-relevant knowledge on management strategies and practices in rangeland-based livestock systems. Copyright

  10. Power and limitation of soil properties as predictors of variation in peak plant biomass in a northern mixed-grass prairie

    Science.gov (United States)

    Soil properties are thought to affect annual plant productivity in rangelands, and thus soil variables that are consistently correlated with variation in plant biomass may be general indicators of rangeland health. Here we measured several soil properties (e.g. aggregate stability, organic carbon, ...

  11. Resilience of soils and vegetation subjected to different grazing ...

    African Journals Online (AJOL)

    The resilience of rangeland soils and vegetation to different levels of grazing is still poorly understood. A study was conducted to determine the recovery of a rangeland grazed at different intensities and allowed a two-year rest period. The following treatments were applied to 0.5 hectare plots: 0, 4, 8 and 16 heifers per ...

  12. Influence of perennial colonies of piscivorous birds on soil nutrient contents in a temperate humid climate

    DEFF Research Database (Denmark)

    Breuning-Madsen, Henrik; Ehlers-Koch, Camilla; Gregersen, Jens

    2010-01-01

    , but the bird’s influence on the soil conditions has only in few cases been studied in detail. In this study the influence of perennial colonies of piscivorous birds on soil nutrient contents and accumulation of carbon, nitrogen and phosphorus in a humid climate has been determined by measuring pH, electric...... conductivity and content of carbon, nitrogen, phosphorus, calcium and potassium in a reference area and in two cormorant sub-colonies. In general, the soils exposed to cormorant guano had lower pH and higher contents of plant available phosphorus, calcium and potassium compared to the control reference soil......, especially in the top horizons, and the magnitude of increase in nutrient content varied with the bird-dropping density and the age of the colony. In addition, soil influenced by cormorants had a higher electric conductivity compared to the control reference and can be classified as saline soils. Under...

  13. Moss Mediates the Influence of Shrub Species on Soil Properties and Processes in Alpine Tundra.

    Directory of Open Access Journals (Sweden)

    C Guillermo Bueno

    Full Text Available In tundra ecosystems, bryophytes influence soil processes directly and indirectly through interactions with overstory shrub species. We experimentally manipulated moss cover and measured seasonal soil properties and processes under two species of deciduous shrubs with contrasting canopy structures, Salix planifolia pulchra and Betula glandulosa-nana complex. Soil properties (seasonal temperature, moisture and C:N ratios and processes (seasonal litter decomposition and soil respiration were measured over twelve months. Shrub species identity had the largest influence on summer soil temperatures and soil respiration rates, which were higher under Salix canopies. Mosses were associated with lower soil moisture irrespective of shrub identity, but modulated the effects of shrubs on winter soil temperatures and soil C:N ratios so that moss cover reduced differences in soil winter temperatures between shrub species and reduced C:N ratios under Betula but not under Salix canopies. Our results suggest a central role of mosses in mediating soil properties and processes, with their influence depending on shrub species identity. Such species-dependent effects need to be accounted for when forecasting vegetation dynamics under ongoing environmental changes.

  14. Moss Mediates the Influence of Shrub Species on Soil Properties and Processes in Alpine Tundra.

    Science.gov (United States)

    Bueno, C Guillermo; Williamson, Scott N; Barrio, Isabel C; Helgadóttir, Ágústa; HiK, David S

    2016-01-01

    In tundra ecosystems, bryophytes influence soil processes directly and indirectly through interactions with overstory shrub species. We experimentally manipulated moss cover and measured seasonal soil properties and processes under two species of deciduous shrubs with contrasting canopy structures, Salix planifolia pulchra and Betula glandulosa-nana complex. Soil properties (seasonal temperature, moisture and C:N ratios) and processes (seasonal litter decomposition and soil respiration) were measured over twelve months. Shrub species identity had the largest influence on summer soil temperatures and soil respiration rates, which were higher under Salix canopies. Mosses were associated with lower soil moisture irrespective of shrub identity, but modulated the effects of shrubs on winter soil temperatures and soil C:N ratios so that moss cover reduced differences in soil winter temperatures between shrub species and reduced C:N ratios under Betula but not under Salix canopies. Our results suggest a central role of mosses in mediating soil properties and processes, with their influence depending on shrub species identity. Such species-dependent effects need to be accounted for when forecasting vegetation dynamics under ongoing environmental changes.

  15. The longitudinal translocation characters and the influencing factors of Hg, Cd in the soil

    Directory of Open Access Journals (Sweden)

    Zhang Yujuan

    2006-11-01

    Full Text Available Combining the methods of simulation test and field survey, the longitudinal distribution and the influencing factors of Hg and Cd in the profile in the typical sewage irrigation area were studied in this paper and the result shows: (1 the content distribution of Hg, Cd in the superficial soil profile was higher than that in the bottom and the content decreased with the increase of the depth, the translocation ability of the Hg, Cd in the garden mould and cinnamon soil were lower than that in the paddy soil and fluve-aquic soil, the longitudinal translocation ability of the Cd in the soil profile was stronger than that of Hg; (2 Hg was accumulated in the different soil and has the highest accumulation rate in the paddy soil and the lowest in the cinnamon soil; the translocation order of the Cd in the different was: garden mould > paddy soil > cinnamon soil > fluve-aquic soil; (3 the concentration of Hg, Cd in the soil leacheate increased with the concentration increase of Hg, Cd in the sewage, the migration rate increased with the roughness of the soil quality and decreased with the increase of pH and soil organic matter.

  16. Influence of pine or oak wood on the degradation of alachlor and metalaxyl in soil.

    Science.gov (United States)

    Rodríguez-Cruz, M Sonia; Marín-Benito, Jesús M; Ordax, José M; Azejjel, Hanane; Sánchez-Martín, María J

    2012-03-01

    The objective of this work was to study the influence pine or oak wood added to soil as an amendment (5% w/w) had on the degradation rate of two pesticides, alachlor and metalaxyl, with different hydrophobic character. The formation of pesticide metabolites and the soil dehydrogenase activity in non-amended and amended soil samples were also monitored. The degradation of metalaxyl followed first-order kinetics, while the degradation of alachlor followed first-order or biphasic kinetics in the soil samples studied. The results indicated that the degradation rate was slower for metalaxyl than for alachlor, and for both pesticides followed the order: pine amended soil soil soil. The faster degradation rate in non-amended soil was attributed to the higher sorption of pesticides by wood amended soils. The alachlor ethane sulfonic acid (ESA), and two metalaxyl metabolites (2-[(2,6-dimethylphenyl)-methoxyacetylamino]-propionic acid and N-(2,6-dimethylphenyl)-2-methoxy-acetamide) were detected during the incubation period. Soil dehydrogenase activity recorded close values in non-amended and amended soil treated with alachlor, but it was higher in wood amended soil treated with metalaxyl. Pine and oak wood increase the immobilization of the pesticides studied, but they also limit their bioavailability in soil by decreasing their degradation rate in amended soil. Copyright © 2010 Elsevier Ltd. All rights reserved.

  17. Influence of effective stress on swelling pressure of expansive soils

    Directory of Open Access Journals (Sweden)

    Baille Wiebke

    2016-01-01

    Full Text Available The volume change and shear strength behaviour of soils are controlled by the effective stress. Recent advances in unsaturated soil mechanics have shown that the effective stress as applicable to unsaturated soils is equal to the difference between the externally applied stress and the suction stress. The latter can be established based on the soil-water characteristic curve (SWCC of the soil. In the present study, the evolution of swelling pressure in compacted bentonite-sand mixtures was investigated. Comparisons were made between magnitudes of applied suction, suction stress, and swelling pressure.

  18. Predicting molybdenum toxicity to higher plants: Influence of soil properties

    Energy Technology Data Exchange (ETDEWEB)

    McGrath, S.P., E-mail: steve.mcgrath@bbsrc.ac.u [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Mico, C. [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom); Curdy, R. [Laboratory for Environmental Biotechnology (LBE), Swiss Federal Institute of Technology Lausanne (EPFL) Station 6 CH, 1015 Lausanne (Switzerland); Zhao, F.J. [Soil Science Department, Centre for Soils and Ecosystems Functions, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ (United Kingdom)

    2010-10-15

    The effect of soil properties on the toxicity of molybdenum (Mo) to four plant species was investigated. Soil organic carbon or ammonium-oxalate extractable Fe oxides were found to be the best predictors of the 50% effective dose (ED{sub 50}) of Mo in different soils, explaining > 65% of the variance in ED{sub 50} for four species except for ryegrass (26-38%). Molybdenum concentrations in soil solution and consequently plant uptake were increased when soil pH was artificially raised because sorption of Mo to amorphous oxides is greatly reduced at high pH. The addition of sulphate significantly decreased Mo uptake by oilseed rape. For risk assessment, we suggest that Mo toxicity values for plants should be normalised using soil amorphous iron oxide concentrations. - Amorphous iron oxides or organic carbon were found to be the best predictors of the toxicity threshold values of Mo to higher plants on different soils.

  19. Rangeland monitoring reveals long-term plant responses to precipitation and grazing at the landscape scale

    Science.gov (United States)

    Munson, Seth M.; Duniway, Michael C.; Johanson, Jamin K.

    2015-01-01

    Managers of rangeland ecosystems require methods to track the condition of natural resources over large areas and long periods of time as they confront climate change and land use intensification. We demonstrate how rangeland monitoring results can be synthesized using ecological site concepts to understand how climate, site factors, and management actions affect long-term vegetation dynamics at the landscape-scale. Forty-six years of rangeland monitoring conducted by the Bureau of Land Management (BLM) on the Colorado Plateau reveals variable responses of plant species cover to cool-season precipitation, land type (ecological site groups), and grazing intensity. Dominant C3 perennial grasses (Achnatherum hymenoides, Hesperostipa comata), which are essential to support wildlife and livestock on the Colorado Plateau, had responses to cool-season precipitation that were at least twice as large as the dominant C4 perennial grass (Pleuraphis jamesii) and woody vegetation. However, these C3 perennial grass responses to precipitation were reduced by nearly one-third on grassland ecological sites with fine- rather than coarse-textured soils, and there were no detectable C3 perennial grass responses to precipitation on ecological sites dominated by a dense-growing shrub, Coleogyne ramosissima. Heavy grazing intensity further reduced the responses of C3 perennial grasses to cool-season precipitation on ecological sites with coarse-textured soils and surprisingly reduced the responses of shrubs as well. By using ecological site groups to assess rangeland condition, we were able to improve our understanding of the long-term relationships between vegetation change and climate, land use, and site characteristics, which has important implications for developing landscape-scale monitoring strategies.

  20. Quantification of the inevitable: the influence of soil macrofauna on soil water movement in rehabilitated open-cut mine land

    Science.gov (United States)

    Arnold, S.; Williams, E. R.

    2015-08-01

    Recolonisation of soil by macrofauna (especially ants and termites) in rehabilitated open-cut mine sites is inevitable. In these highly disturbed landscapes, soil invertebrates play a major role in soil development (macropore configuration, nutrient cycling, bioturbation, etc.) and can influence hydrological processes such as infiltration and seepage. Understanding and quantifying these ecosystem processes is important in rehabilitation design, establishment and subsequent management to ensure progress to the desired end-goal, especially in waste cover systems designed to prevent water reaching and transporting underlying hazardous waste materials. However, soil macrofauna are typically overlooked during hydrological modelling, possibly due to uncertainties on the extent of their influence, which can lead to failure of waste cover systems or rehabilitation activities. We propose that scientific experiments under controlled conditions are required to quantify (i) macrofauna - soil structure interactions, (ii) functional dynamics of macrofauna taxa, and (iii) their effects on macrofauna and soil development over time. Such knowledge would provide crucial information for soil water models, which would increase confidence in mine waste cover design recommendations and eventually lead to higher likelihood of rehabilitation success of open-cut mining land.

  1. Opportunities and obstacles for rangeland conservation in San Diego County, California, USA

    Directory of Open Access Journals (Sweden)

    Kathleen A. Farley

    2017-03-01

    Full Text Available Working landscapes such as rangelands are increasingly recognized as having high conservation value, providing a variety of ecosystem services, including food, fiber, habitat, recreation, open space, carbon storage, and water, in addition to a broad range of social benefits. However, conversion of rangelands to other land uses has been prevalent throughout the western United States, leading to greater attention in the conservation community to the importance of collaborating with private landowners. The level of interest in collaborative conservation among private landowners and the types of conservation programs they choose to participate in depend on the social, economic, and environmental context. We used GIS analysis and interviews with ranchers to evaluate rangeland conversion and participation in conservation programs among ranchers in San Diego County, California, USA, which is part of a biodiversity hotspot with high plant species richness and a large number of endemic and rare species. We found that > 25% of rangelands were converted to other uses, primarily urbanization, over the past 25 years while the area of public rangeland increased by 9%. Interviews revealed that ranchers in San Diego County have had limited involvement with most conservation programs, and a critical factor for nonparticipation was providing programs access to private land, along with other issues related to trust and social values. Among ranchers who had participated in conservation programs, the payment level and the agency or organization administering the program were key factors. Our results provide insight into factors influencing whether and when ranchers are likely to participate in conservation initiatives and illustrate that private and public land conservation are strongly linked and would be more effective if the two strategies were better integrated.

  2. Degradation kinetics of forchlorfenuron in typical grapevine soils of India and its influence on specific soil enzyme activities.

    Science.gov (United States)

    Banerjee, Kaushik; Dasgupta, Soma; Oulkar, Dasharath P; Patil, Sangram H; Adsule, Pandurang G

    2008-05-01

    The rate of degradation of forchlorfenuron, a cytokinin-based plant growth regulator (PGR) was explored in typical grapevine soils of India with simultaneous evaluation of its effect on biochemical attributes of the test soils in terms of the activities of specific soil microbial enzymes. In all the test soils, namely clay, sandy-loam and silty-clay, the dissipation rate was faster at the beginning, which slowed down with time, indicating a non-linear pattern of degradation. Degradation in soils could best be explained by two-compartment 1st+1st order kinetics with half-life ranging between 4-10 days. The results suggest that organic matter might be playing a major role in influencing the rate of degradation of forchlorfenuron in soil. The rate of degradation in sandy-loam soil was fastest followed by clay and silty-clay soils, respectively. Comparison of the rate of degradation in natural against sterilized soils suggests that microbial degradation might be the major pathway of residue dissipation. Changes in soil enzyme activities as a consequence of forchlorfenuron treatment were studied for extra-cellular enzymes namely acid phosphatase, alkaline phosphatase and beta -glucosidase and intracellular enzyme-dehydrogenase. Although small changes in enzyme activities were observed, forchlorfenuron did not have any significant deleterious effect on the enzymatic activity of the test soils. Simple correlation studies between degradation percentage and individual enzyme activities did not establish any significant relationships. The pattern and change of enzyme activity was primarily the effect of the incubation period rather than the effect of forchlorfenuron itself.

  3. Influence of soil structure on contaminant leaching from injected slurry.

    Science.gov (United States)

    Amin, M G Mostofa; Pedersen, Christina Østerballe; Forslund, Anita; Veith, Tamie L; Laegdsmand, Mette

    2016-12-15

    Animal manure application to agricultural land provides beneficial organic matter and nutrients but can spread harmful contaminants to the environment. Contamination of fresh produce, surface water and shallow groundwater with the manure-borne pollutants can be a critical concern. Leaching and persistence of nitrogen, microorganisms (bacteriophage, E. coli, and Enterococcus) and a group of steroid hormone (estrogens) were investigated after injection of swine slurry into either intact (structured) or disturbed (homogeneous repacked) soil. The slurry was injected into hexaplicate soil columns at a rate of 50 t ha-1 and followed with four irrigation events: 3.5-h period at 10 mm h-1 after 1, 2, 3, and 4 weeks. The disturbed columns delayed the leaching of a conservative tracer and microorganisms in the first irrigation event compared to the intact columns due to the effect of disturbed macropore flow paths. The slurry constituents that ended up in or near the macropore flow paths of the intact soil were presumably washed out relatively quickly in the first event. For the last three events the intact soil leached fewer microorganisms than the disturbed soil due to the bypassing effect of water through the macropore flow path in the intact soil. Estrogen leached from the intact soil in the first event only, but for the disturbed soil it was detected in the leachates of last two events also. Leaching from the later events was attributed to higher colloid transport from the disturbed soils. In contrast, NO3-N leaching from the intact soil was higher for all events except the first event, probably due to a lower nitrification rate in the disturbed soil. A week after the last irrigation event, the redistribution of all slurry constituents except NO3-N in most of the sections of the soil column was higher for the disturbed soil. Total recovery of E. coli was significantly higher from the disturbed soil and total leaching of mineral nitrogen was significantly lower

  4. Influence of soil on groundwater geochemistry in a carbonate aquifer, southern Italy

    Directory of Open Access Journals (Sweden)

    Tiziano Boschetti

    2014-01-01

    Full Text Available The role of soil compositions in influencing groundwater geochemistry in carbonate aquifers is still little known. Nothing is known regarding the influence of pyroclastic soils (andisol within the carbonate Apennines in central-southern Italy, despite their wide distribution. In this study we analyze some physical and chemical properties of pyroclastic soil at the Acqua dei Faggi experimental site (southern Italy, to assess its influence on groundwater geochemistry. Chemical analyses were carried out on saturated paste extracts and a physical analogue model was developed through two column experiments. Physico-chemical properties of rainwater and spring water, and some microbiological features of the soil medium were also taken into consideration. The studied soil has a great influence in modifying rainwater chemistry during percolation. About the 50% of HCO3- and Ca2+ in spring water is due to interaction between percolation water and soil medium, and equilibrium with calcite is reached at this stage. The Na+/K+ ratio is buffered by clay minerals in the soil by primary silicates in the pyroclastic cover and then buffered. Cl- and SO42- concentrations in spring water are very close to that of soil infiltration water during short-term interaction with soil, but a decline is showed during long-term cause to the anions adsorption effect in the andisol. Chemical and microbiological investigations show the existence of a soil microbial community that allows denitrification and nitrate reduction. Infiltration processes cause anoxic conditions within the soil medium, therefore the absence of NH4+ in spring water throughout the observation period should be due to anammox processes. These findings suggest that hydrochemistry and spring chemographs may be significantly influenced by several factors, such as relationships between soil and rainwater, vegetation, and microbial communities, which are not necessarily correlated with lithological and structural

  5. Influence of Xenobiotic Substances on Actinomycete Comunities in Soil

    OpenAIRE

    Marioara Nicoleta Filimon; Roxana Popescu; Aurica Breica Borozan; Despina Maria Bordean; Gabi Dumitrescu; Sorin Octavian Voia

    2012-01-01

    Sulfonylurea herbicides are frequently used in agricultural crops even if they determine quantitative and qualitativechanges in soil microbial communities. In this study it was used increasing doses of two sulfonylurea herbicides,tribenuron-methyl and nicosulfuron, in order to establish their effect on actinomyces communities from soil underlaboratory conditions. Using nutritive gelose with soil extract and Gause medium the main species of actinomyceswere identified: Streptomyces albus, Strep...

  6. Soil type influence on Ag Nanoparticles by earthworms, Eisenia fetida

    DEFF Research Database (Denmark)

    Mariyadas, Jennifer; Mónica, Amorim; Scott-Fordsmand, Janeck James

    2014-01-01

    Earthworms are key sentinel organisms playing an important role in improving the soil structure. Here we tested the importance of soil type on the toxicity to silver nanoparticles (Ag NPs) to earthworms, Eisenia fetida. Silver nanoparticles are widely used in a range of consumer products mainly...... matter content, clay and cation exchange capacity along with the metal solution activity will provide insight into the bioavailability of metals in different soils, hence For each of the soil type the fate of the AgNPs was also measured....

  7. Plant and bird presence strongly influences the microbial communities in soils of Admiralty Bay, Maritime Antarctica.

    Directory of Open Access Journals (Sweden)

    Lia C R S Teixeira

    Full Text Available Understanding the environmental factors that shape microbial communities is crucial, especially in extreme environments, like Antarctica. Two main forces were reported to influence Antarctic soil microbes: birds and plants. Both birds and plants are currently undergoing relatively large changes in their distribution and abundance due to global warming. However, we need to clearly understand the relationship between plants, birds and soil microorganisms. We therefore collected rhizosphere and bulk soils from six different sampling sites subjected to different levels of bird influence and colonized by Colobanthus quitensis and Deschampsia antarctica in Admiralty Bay, King George Island, Maritime Antarctic. Microarray and qPCR assays targeting 16S rRNA genes of specific taxa were used to assess microbial community structure, composition and abundance and analyzed with a range of soil physico-chemical parameters. The results indicated significant rhizosphere effects in four out of the six sites, including areas with different levels of bird influence. Acidobacteria were significantly more abundant in soils with little bird influence (low nitrogen and in bulk soil. In contrast, Actinobacteria were significantly more abundant in the rhizosphere of both plant species. At two of the sampling sites under strong bird influence (penguin colonies, Firmicutes were significantly more abundant in D. antarctica rhizosphere but not in C. quitensis rhizosphere. The Firmicutes were also positively and significantly correlated to the nitrogen concentrations in the soil. We conclude that the microbial communities in Antarctic soils are driven both by bird and plants, and that the effect is taxa-specific.

  8. Influence of Disturbance on Soil Respiration in Biologically Crusted Soil during the Dry Season

    Directory of Open Access Journals (Sweden)

    Wei Feng

    2013-01-01

    Full Text Available Soil respiration (Rs is a major pathway for carbon cycling and is a complex process involving abiotic and biotic factors. Biological soil crusts (BSCs are a key biotic component of desert ecosystems worldwide. In desert ecosystems, soils are protected from surface disturbance by BSCs, but it is unknown whether Rs is affected by disturbance of this crust layer. We measured Rs in three types of disturbed and undisturbed crusted soils (algae, lichen, and moss, as well as bare land from April to August, 2010, in Mu Us desert, northwest China. Rs was similar among undisturbed soils but increased significantly in disturbed moss and algae crusted soils. The variation of Rs in undisturbed and disturbed soil was related to soil bulk density. Disturbance also led to changes in soil organic carbon and fine particles contents, including declines of 60–70% in surface soil C and N, relative to predisturbance values. Once BSCs were disturbed, Q10 increased. Our findings indicate that a loss of BSCs cover will lead to greater soil C loss through respiration. Given these results, understanding the disturbance sensitivity impact on Rs could be helpful to modify soil management practices which promote carbon sequestration.

  9. Sorption and degradation of carbaryl in soils amended with biochars: influence of biochar type and content.

    Science.gov (United States)

    Ren, Xinhao; Zhang, Peng; Zhao, Lijie; Sun, Hongwen

    2016-02-01

    Biochars that were produced from three different biomass materials were amended to a soil to elucidate their influence on the fate of carbaryl. Sorption and degradation of carbaryl in soils amended with the biochars were investigated. The results showed that the amendment of biochars to soil enhanced the sorption of carbaryl. The nonlinearity of sorption isotherm and sorption affinity of carbaryl increased with the content and pyrolytic temperature of the biochars. Both chemical and biological degradation of carbaryl were influenced by biochars. The biochars enhanced the chemical hydrolysis of carbaryl in soil, with biochars produced at 700 °C (BC700) exhibiting greater impact, due to their strong liming effect. In contrast, BC350 (produced at 350 °C) promoted the biodegradation of carbaryl in soil by different extents, while BC700 obviously reduced the biodegradation of carbaryl. The enhanced activities of natural microorganisms in the soil and the lowered bioavailability of carbaryl acted together to determine the biodegradation.

  10. Hydrogeomorphology influences soil nitrogen and phosphorus mineralization in floodplain wetlands

    Science.gov (United States)

    Noe, Gregory B.; Hupp, Cliff R.; Rybicki, Nancy B.

    2013-01-01

    Conceptual models of river–floodplain systems and biogeochemical theory predict that floodplain soil nitrogen (N) and phosphorus (P) mineralization should increase with hydrologic connectivity to the river and thus increase with distance downstream (longitudinal dimension) and in lower geomorphic units within the floodplain (lateral dimension). We measured rates of in situ soil net ammonification, nitrification, N, and P mineralization using monthly incubations of modified resin cores for a year in the forested floodplain wetlands of Difficult Run, a fifth order urban Piedmont river in Virginia, USA. Mineralization rates were then related to potentially controlling ecosystem attributes associated with hydrologic connectivity, soil characteristics, and vegetative inputs. Ammonification and P mineralization were greatest in the wet backswamps, nitrification was greatest in the dry levees, and net N mineralization was greatest in the intermediately wet toe-slopes. Nitrification also was greater in the headwater sites than downstream sites, whereas ammonification was greater in downstream sites. Annual net N mineralization increased with spatial gradients of greater ammonium loading to the soil surface associated with flooding, soil organic and nutrient content, and herbaceous nutrient inputs. Annual net P mineralization was associated negatively with soil pH and coarser soil texture, and positively with ammonium and phosphate loading to the soil surface associated with flooding. Within an intensively sampled low elevation flowpath at one site, sediment deposition during individual incubations stimulated mineralization of N and P. However, the amount of N and P mineralized in soil was substantially less than the amount deposited with sedimentation. In summary, greater inputs of nutrients and water and storage of soil nutrients along gradients of river–floodplain hydrologic connectivity increased floodplain soil nutrient mineralization rates.

  11. Role of traditional enclosures on the diversity of herbaceous vegetation in a semi-arid rangeland, southern Ethiopia

    NARCIS (Netherlands)

    Angassa, A.; Oba, G.; Treydte, A.C.; Weladji, R.B.

    2010-01-01

    Grazing management and seasonality strongly influence the recovery potential of herbaceous vegetation in semi-arid rangelands of southern Ethiopia after history of heavy grazing. We investigated effects of management (enclosures versus grazed landscapes), age of enclosures and seasonality related to

  12. Influence of Mango Based Intercropping Systems on Soil Health ...

    African Journals Online (AJOL)

    Among different intercropping systems tried, the mango + guava + cowpea system resulted in maximum improvement in bulk density, electrical conductivity, water holding capacity, organic carbon content and pH within 0 - 15 and 15 - 30 cm of soil depths. The nutrient status of orchard soil indicated that the mango + guava + ...

  13. THE INFLUENCE OF SOME SOIL CHEMICAL PROPERTIES ON THEIR ERODABILITY

    Directory of Open Access Journals (Sweden)

    I. C. Stanga

    2005-10-01

    Full Text Available Soils from de hills and tableland regions, as well as those from subcarpathian area are characterized through higher erodability. The soils from mountain area present the lowest erodability, especially districambosol, due to the upper horizons properties. The erodabilidydepends on the ratio of historical geological erosion and surface erosion.

  14. Soil strength properties as influenced by tillage under soybean ...

    African Journals Online (AJOL)

    The results in general, demonstrated that sealing of soil surface due to raindrop impact can be minimized to some extent by tillage. A regression model for tillage treatments with indicator variables for crop development, soil compaction and time was also developed using field data. The models reveal the need to minimize ...

  15. The Influence of Cattle Wastes on Degraded Savanna Soils of ...

    African Journals Online (AJOL)

    ... people on adoption of mixed farming and land use and soil properties because they tend to affect each other. Fulani nomads and arable farmers should be encouraged to co-exist harmoniously with farming communities as this would encourage sustainable crop production in low to moderate fertile soils of the tropics.

  16. Influence of vermicompost on soil chemical and physical properties ...

    African Journals Online (AJOL)

    STORAGESEVER

    2008-07-18

    Jul 18, 2008 ... Orozco FH, Cegarra J, Trujillo LM, Roig A (1996). Vermicomposting of coffee pulp using the earthworm Eisenia fetida: effects on C and N contents and the availability of nutrients. Biol. Fert. Soils 22: 162-166. Pagliai M, Guidi G, La Marca M (1980). Macro_and microorphometric investigation on soil- dextran ...

  17. Influence of Cultivation and Cropping Systems on Production of Soil Sediment on Agricultural Land

    Science.gov (United States)

    Poposka, Hristina; Mukaetov, Dusko

    2017-04-01

    Soil conservation practices and in particular soil tillage and crop cultivation patterns are becoming an important issue in agricultural production. Combating soil erosion and diminishing its negative impact on agricultural soil imposes as a matter of vital interest which gained even greater significance, in a pronounced negative impact of climate change. Main objective of the three-year research and monitoring program was to evaluate the effects of the easy-to-use adaptive measures on intensity of soil erosion, and soil properties considering to be of crucial importance on run-off velocity and sediment loss, like: soil structure stability, soil infiltration rate, soil organic matter and soil moisture conservation. The influence of soil tillage practices and different cropping systems on soil intensity and sediment loss, has been monitored on specially designed soil erosion fields with standard dimensions (20m length x 4m. width), on a sloppy terrain (12% slope). The experimental field is located on heavily textured Chromic cambisol on saprolite. This is the predominant soil type on the sloppy terrains in the country, usually under intensive agricultural activities Soil texture and physical characteristics were thoroughly investigated in order to determine the base soil conditions. The influence of downslope and contour ploughing on quantity of eroded sediment has been monitored in three consecutive years. The eroded sediment has been collected periodically on a weekly base and after intensive rainfalls. The intensity of soil erosion under most widespread cropping systems in the country, like: a) cereals as a monoculture, b) crop rotation, and c) perennial grass, was monitored as well. The collected sediment was examined in order to determine the quantity of soil organic matter and nutrient loss (nitrogen, phosphorus and potassium). Soil chemical properties are examined after each vegetative season in order to quantify the effect of tillage and cropping systems on

  18. Influence of Soil Moisture on Soil Gas Vapor Concentration for Vapor Intrusion

    Science.gov (United States)

    Shen, Rui; Pennell, Kelly G.; Suuberg, Eric M.

    2013-01-01

    Abstract Mathematical models have been widely used in analyzing the effects of various environmental factors in the vapor intrusion process. Soil moisture content is one of the key factors determining the subsurface vapor concentration profile. This manuscript considers the effects of soil moisture profiles on the soil gas vapor concentration away from any surface capping by buildings or pavement. The “open field” soil gas vapor concentration profile is observed to be sensitive to the soil moisture distribution. The van Genuchten relations can be used for describing the soil moisture retention curve, and give results consistent with the results from a previous experimental study. Other modeling methods that account for soil moisture are evaluated. These modeling results are also compared with the measured subsurface concentration profiles in the U.S. EPA vapor intrusion database. PMID:24170970

  19. Influence of long-term fertilization on soil enzyme activities

    Directory of Open Access Journals (Sweden)

    Alina Dora SAMUEL

    2009-05-01

    Full Text Available Soil enzyme activities (actual and potential dehydrogenase, catalase, acid and alkaline phosphatase were determined in the 0–10, 10–20, and 20–30 cm layers of a brown luvic soil submitted to a complex fertilization experiment with different types of green manure. It was found that each activity decreased with increasing sampling depth. It should be emphasized that greenmanuring of maize led to a significant increase in each of the five enzymatic activities determined. The enzymatic indicators of soil quality calculated from the values of enzymatic activities showed the order: lupinus + rape + oat > lupinus > vetch + oat + ryegrass > lupinus + oat + vetch > unfertilized plot. This order means that by determination of enzymatic activities valuable information can be obtained regarding fertility status of soils. There were significant correlations of soil enzyme activities with chemical properties.

  20. Earthworm bioturbation influences the phytoavailability of metals released by particles in cultivated soils.

    Science.gov (United States)

    Leveque, Thibaut; Capowiez, Yvan; Schreck, Eva; Xiong, Tiantian; Foucault, Yann; Dumat, Camille

    2014-08-01

    The influence of earthworm activity on soil-to-plant metal transfer was studied by carrying out six weeks mesocosms experiments with or without lettuce and/or earthworms in soil with a gradient of metal concentrations due to particles fallouts. Soil characteristics, metal concentrations in lettuce and earthworms were measured and soil porosity in the mesocosms was determined. Earthworms increased the soil pH, macroporosity and soil organic matter content due to the burying of wheat straw provided as food. Earthworm activities increased the metals concentrations in lettuce leaves. Pb and Cd concentrations in lettuce leaves can increase up to 46% with earthworm activities … These results and the low correlation between estimated by CaCl2 and EDTA and measured pollutant phytoavailability suggest that earthworm bioturbation was the main cause of the increase. Bioturbation could affect the proximity of pollutants to the roots and soil organic matter. Copyright © 2014 Elsevier Ltd. All rights reserved.

  1. Impacts of deforestation and reforestation on soil organic carbon storage and CO2 emission

    Directory of Open Access Journals (Sweden)

    Mohammad Ghannadi

    2013-05-01

    Full Text Available Soil organic carbon (SOC storage and CO2 flux into the atmosphere can be influenced by land use change, especially re/deforestation. The impacts of conversion of primary deciduous (PF to secondary coniferous (SF forest and deforestation of PF land to abandoned rangeland (AR on various soil properties, SOC storage, and soil CO2 emission were investigated on the selected sites (Neshat and Garakpass in Kelardasht region, northern Iran. The highest SOC storages were determined in coniferous forest land uses (SF1=255.00 and SF2=237.90 Mg C ha−1 followed by deciduous forest (PF1=216.74 and PF2=159.12 Mg C ha−1 and abandoned rangeland (AR1=185.31 and AR2=151.60 Mg C ha−1. Land use changes showed significant impacts on soil CO2 efflux. The significant positive correlations, with exponential and linear relationships were observed between the monthly CO2 emissions; the minimum air temperature and the cumulative precipitation in the last week ended to CO2 measurement time. The highest recorded soil CO2 efflux in a wide range of land uses were obtained in August to October due to more suitable temperature and rainfall distribution. Based on lower CO2 emission in abandoned rangelands, lesser soil organic carbon is related to lower input to soil. The higher C: N ratios in litter and some of mineral horizons (SF2 and lower CO2 emissions by the higher lignin and polyphenol concentrations (SF1 in coniferous forests compared to deciduous forests have probably caused increasing SOC storage.

  2. Grazing and soil erosion in dehesas of SW Spain

    Energy Technology Data Exchange (ETDEWEB)

    Schnabel, S.; Gomez Gutierrez, A.; Lavado Contador, J. L.

    2009-07-01

    Water erosion and its relation to livestock grazing in semi-arid to dry sub humid Mediterranean rangelands with a disperse tree cover is analyzed, based on a variety of studies carried out since 1990 in Extremadure, Spain. The dominant factors of sheet wash are rainfall intensity and soil surface cover, the latter being controlled by rainfall amounts and livestock density. The discontinuous valley bottom gullies present a complex relationship with catchment hydrology. giving the high temporal variability of sediment losses, the influence of livestock on gully erosion is difficult to determine with short-tern studied. (Author) 4 refs.

  3. INFLUENCE OF USUAL AND DUAL WHEELS ON SOIL PENETRATION RESISTANCE: THE GIS-APPROACH

    Directory of Open Access Journals (Sweden)

    A. V. Zhukov

    2015-11-01

    Full Text Available GIS-APPROACH application has allowed establishing that usual wheels of machine-tractor units carry out considerable influence on soil which exceeds visible borders of a track of wheels on the dimensions. This influence shows in augmentation of soil penetration resistance at 100-155 % in comparison with the control on depth of 0-10 cm and on 20-30 % on depth of 45-50 %. It is impossible to exclude that influence of wheels proceeds more deeply, than tests have been conducted. Critical for cultivated plants value of soil penetration resistance in 3 MPa under the influence of usual wheels of agricultural machinery comes nearer practically to a surface. Character of profile changes of hardness in various regions influences of wheels allows assuming the long season of a relaxation of soil for achievement of background values of soil penetration resistance. The further researches are necessary for an establishment of concrete indicators of dynamics. Negative influence of an overstocking does not confine only deterioration of conditions of growth of assemblages of rootlets of plants. Infringement of processes of moving of moisture in the soil, the accelerated evaporation and the slowed down processes of a filtration and an infiltration, destruction of modular frame, activization of erosive processes is possible. The understanding of these processes will give the chance volume understanding of real influence of running systems of machine-tractor devices on bedrock. Region intensive influence of dual wheels is circumscribed by the top soil layers (0-15 cm. The major feature of influence of dual wheels is absence of an overstocking above critical levels. It is impossible to exclude possible positive influence of moderate inspissations of soil under the influence of dual wheels for growth of agricultural crops and moisture conservation in soil. The cumulative negative effect on soil crossed vehicles traces is probable. The long season of a relaxation of

  4. Influence of soil structure on the "Fv approach" applied to 238U and 226Ra.

    Science.gov (United States)

    Blanco Rodríguez, P; Vera Tomé, F; Lozano, J C

    2017-02-01

    The soil-to-plant transfer factors were determined in a granitic area for the two long-lived uranium series radionuclides 238U and 226Ra. With the aim to identify a physical fraction of soil whose concentration correlates linearly with the plant concentration, the soil compartment was analyzed in various stages. An initial study identified the soil compartments as being either bulk soil or its labile fraction. The bulk soil was subsequently divided into three granulometric fractions consisting of: coarse sand, fine sand, and silt and clay. The soil-to-plant transfer of radionuclides for each of these three texture fractions was analyzed. Lastly, the labile fraction was extracted from each textural part, and the activity concentration of the radionuclides 238U and 226Ra was measured. In order to assess the influence of soil texture on the soil-to-plant transfer process, we sought to identify possible correlations between the activity concentration in the plant compartment and those found in the different fractions within each soil compartment. The results showed that the soil-to-plant transfer process for uranium and radium depends on soil grain size, where the results for uranium showed a linear relationship between the activity concentration of uranium in the plant and the fine soil fraction. In contrast, a linear relation between the activity concentration of radium in the plant and the soil coarse-sand fraction was observed. Additionally, the presence of phosphate and calcium in the soil of all of the compartments studied affected the soil-to-plant transfer of uranium and radium, respectively. Copyright © 2016 Elsevier Ltd. All rights reserved.

  5. Influence of soil properties and soil moisture on the efficacy of indaziflam and flumioxazin on Kochia scoparia L.

    Science.gov (United States)

    Sebastian, Derek J; Nissen, Scott J; Westra, Phil; Shaner, Dale L; Butters, Greg

    2017-02-01

    Kochia (Kochia scoparia L.) is a highly competitive, non-native weed found throughout the western United States. Flumioxazin and indaziflam are two broad-spectrum pre-emergence herbicides that can control kochia in a variety of crop and non-crop situations; however, under dry conditions, these herbicides sometimes fail to control this important weed. There is very little information describing the effect of soil properties and soil moisture on the efficacy of these herbicides. Soil organic matter (SOM) explained the highest proportion of variability in predicting the herbicide dose required for 80% kochia growth reduction (GR80 ) for flumioxazin and indaziflam (R2 = 0.72 and 0.79 respectively). SOM had a greater impact on flumioxazin phytotoxicity compared to indaziflam. Flumioxazin and indaziflam kochia phytotoxicity was greatly reduced at soil water potentials below -200 kPa. Kochia can germinate at soil moisture potentials below the moisture required for flumioxazin and indaziflam activation, which means that kochia control is greatly influenced by the complex interaction between soil physical properties and soil moisture. This research can be used to gain a better understanding of how and why some weeds, like kochia, are so difficult to manage even with herbicides that normally provide excellent control. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  6. Soil biota in vineyards are more influenced by plants and soil quality than by tillage intensity or the surrounding landscape.

    Science.gov (United States)

    Buchholz, Jacob; Querner, Pascal; Paredes, Daniel; Bauer, Thomas; Strauss, Peter; Guernion, Muriel; Scimia, Jennifer; Cluzeau, Daniel; Burel, Françoise; Kratschmer, Sophie; Winter, Silvia; Potthoff, Martin; Zaller, Johann G

    2017-12-12

    Tillage is known for its adverse effects on soil biota, at least in arable agroecosystems. However, in vineyards effects might differ as tillage is often performed during dry periods or only in every other inter-row allowing species to re-colonise disturbed areas. We examined the response of earthworms (lumbricids), springtails (collembola) and litter decomposition to periodically mechanically disturbed (PMD) and permanently green covered (PGC) vineyard inter-rows and assessed whether site effects are altered by the surrounding landscape. In commercial vineyards in Austria we sampled earthworms by handsorting, springtails by soil coring and pitfall trapping and installed litter decomposition bags. Earthworm species diversity increased with plant biomass under PMD but not under PGC; earthworm density was unaffected by tillage but increased with plant biomass mainly at high soil quality (soil fertility index). Springtail species diversity was unaffected by tillage; springtail densities (mainly larger species) were reduced under PGC. Litter decomposition was little affected by investigated parameters. Landscape heterogeneity affected the functional diversity of surface springtails, but did not influence soil-dwelling springtails, earthworms or litter decomposition. We conclude that effects on soil biota of periodical tillage in vineyards need not necessarily be detrimental and will be modified by plant biomass and soil quality.

  7. Influence of Oil on the Magnitude and Rate of Collapsible Soils ...

    African Journals Online (AJOL)

    Collapsible soils particularly cover arid and semi arid regions where sometimes petroleum industry is well developed. The hydrocarbon is transported by pipelines towards refineries located in coastal areas. In case of a leak, these soils may collapse. The experimental work, carried out in oedometer illustrates the influence ...

  8. Influence of plant prunings on soil properties and yield of yam minisett

    African Journals Online (AJOL)

    The importance of the application of agroforestry prunings on improvement of the soil organic matter cannot be overemphasized. The study focused on the influence of plant prunings on soil properties and yield of yam minisett. There is no doubt that effective production of seed yam through minisett technique requires ...

  9. Variability in urban soils influences the health and growth of native tree seedlings

    Science.gov (United States)

    Clara C. Pregitzer; Nancy F. Sonti; Richard A. Hallett

    2016-01-01

    Reforesting degraded urban landscapes is important due to the many benefits urban forests provide. Urban soils are highly variable, yet little is known about how this variability in urban soils influences tree seedling performance and survival. We conducted a greenhouse study to assess health, growth, and survival of four native tree species growing in native glacial...

  10. The influence of surface reflectance anisotropy on estimation of soil properties

    Science.gov (United States)

    Bartholomeus, Harm; Roosjen, Peter; Clevers, Jan

    2014-05-01

    The spatial variation in soil properties is an important factor for agricultural management. Unmanned airborne vehicles (UAV's) equipped with a hyperspectral mapping system may provide these data, but anisotropic reflectance effects may have an influence on the derived soil properties. Besides influencing the reflectance, angular observations may deliver added information about soil properties. We investigated the anisotropic behavior of 59 soil samples with a large variation in soil composition, by measuring their reflectance (350-2500 nm) over 92 different angles using a robot-based laboratory goniometer system. The results show that the anisotropic behavior of the soils influences the measured reflectance significantly, which limits the accurate prediction of soil properties (OM and clay especially). However, prediction accuracies of OM increase when spectra are measured under specific angles. Prediction accuracies further increase when a combination of observation angles is being used. Apart from that, using UAV's the wavelength range is limited to about 1000 nm. In general, this will decrease the model performance, but our results show that this effect can largely be compensated by combining multiple observation angles. Altogether, we demonstrate that surface anisotropy influences the prediction of soil properties negatively. This effect can be reduced by combining spectra acquired under different angles. Moreover, predictions can be improved if combinations of different observation angles are used.

  11. Microelements in sierozem soils of Nakhichevan Autonomous Republic and their influence of sugar beet yield

    Directory of Open Access Journals (Sweden)

    B. K. Shakury

    2009-01-01

    Full Text Available Results on study of sierozem soils properties in one of the most interesting natural Azerbaijan region – Nakhichevan Autonomous Republic are presented in article. The problems of soil geochemistry and microelements doses influence on sugur beet yield are discussed.

  12. Development of earthworm burrow systems and the influence of earthworms on soil hydrology

    NARCIS (Netherlands)

    Ligthart, T.N.

    1996-01-01


    Inoculation of earthworms can help to restore or ameliorate land qualities. Earthworms create burrows and alter the structure of the soil matrix, which influence the water infiltration, drainage, water retention and the aeration of the soil. The way and rate of the development of

  13. Introducing cattle grazing to a noxious weed-dominated rangeland shifts plant communities

    Directory of Open Access Journals (Sweden)

    Josh S. Davy

    2015-10-01

    Full Text Available Invasive weed species in California's rangelands can reduce herbaceous diversity, forage quality and wildlife habitat. Small-scale studies (5 acres or fewer have shown reductions of medusahead and yellow starthistle using prescribed grazing on rangelands, but little is published on the effects of pasture-scale (greater than 80 acres prescribed grazing on weed control and plant community responses. We report the results of a 6-year collaborative study of manager-applied prescribed grazing implemented on rangeland that had not been grazed for 4 years. Grazing reduced medusahead but did not alter yellow starthistle cover. Medusahead reductions were only seen in years that did not have significant late spring rainfall, suggesting that it is able to recover from heavy grazing if soil moisture is present. Later season grazing appears to have the potential to suppress medusahead in all years. In practice, however, such grazing is constrained by livestock drinking water availability and forage quality, which were limited even in years with late spring rainfall. Thus, we expect that grazing treatments under real-world constraints would reduce medusahead only in years with little late spring rainfall. After 10 years of grazing exclusion, the ungrazed plant communities began to shift, replacing medusahead with species that have little value, such as ripgut and red brome.

  14. Study of the trace metal ion influence on the turnover of soil organic matter in cultivated contaminated soils.

    Science.gov (United States)

    Dumat, C; Quenea, K; Bermond, A; Toinen, S; Benedetti, M F

    2006-08-01

    The role of metals in the behaviour of soil organic matter (SOM) is not well documented. Therefore, we investigated the influence of metals (Pb, Zn, Cu and Cd) on the dynamic of SOM in contaminated soils where maize (C4 plant) replaced C3 cultures. Three pseudogley brown leached soil profiles under maize with a decreasing gradient in metals concentrations were sampled. On size fractions, stable carbon isotopic ratio (delta13C), metals, organic carbon and nitrogen concentrations were measured in function of depth. The determined sequence for the amount of C4 organic matter in the bulk fractions: M3 (0.9)>M2 (0.4)>M1 (0.3) is in agreement with a significant influence of metals on the SOM turnover. New C4 SOM, mainly present in the labile coarser fractions and less contaminated by metals than the stabilised C3 SOM of the clay fraction, is more easily degraded by microorganisms.

  15. Does plant species co-occurrence influence soil mite diversity?

    Science.gov (United States)

    St John, Mark G; Wall, Diana H; Behan-Pelletier, Valerie M

    2006-03-01

    Few studies have considered whether plant taxa can be used as predictors of belowground faunal diversity in natural ecosystems. We examined soil mite (Acari) diversity beneath six grass species at the Konza Prairie Biological Station, Kansas, USA. We tested the hypotheses that soil mite species richness, abundance, and taxonomic diversity are greater (1) beneath grasses in dicultures (different species) compared to monocultures (same species), (2) beneath grasses of higher resource quality (lower C:N) compared to lower resource quality, and (3) beneath heterogeneous mixes of grasses (C3 and C4 grasses growing together) compared to homogeneous mixes (C3 or C4 grasses) using natural occurrences of plant species as treatments. This study is the first to examine the interaction between above- and belowground diversity in a natural setting with species-level resolution of a hyper-diverse taxon. Our results indicate that grasses in diculture supported a more species and phylogenetically rich soil mite fauna than was observed for monocultures and that this relationship was significant at depth but not in the upper soil horizon. We noted that mite species richness was not linearly related to grass species richness, which suggests that simple extrapolations of soil faunal diversity based on plant species inventories may underestimate the richness of associated soil mite communities. The distribution of mite size classes in dicultures was considerably different than those for monocultures. There was no difference in soil mite richness between grass combinations of differing resource quality, or resource heterogeneity.

  16. INFLUENCE OF USUAL AND DUAL WHEELS ON SOIL PENETRATION RESISTANCE: THE GIS-APPROACH

    Directory of Open Access Journals (Sweden)

    Zhukov A. V.

    2015-12-01

    Full Text Available GIS-APPROACH application has allowed establishing that usual wheels of machine-tractor units carry out considerable influence on soil which exceeds visible borders of a track of wheels on the dimensions. This influence shows in augmentation of soil penetration resistance at 100-155 % in comparison with the control on depth of 0-10 cm and on 20-30 % on depth of 45-50 %. It is impossible to exclude that influence of wheels proceeds more deeply, than tests have been conducted. Critical for cultivated plants value of soil penetration resistance in 3 MPa under the influence of usual wheels of agricultural machinery comes nearer practically to a surface. Character of profile changes of hardness in various regions influences of wheels allows assuming the long season of a relaxation of soil for achievement of background values of soil penetration resistance. The further researches are necessary for an establishment of concrete indicators of dynamics. Negative influence of an overstocking does not confine only deterioration of conditions of growth of assemblages of rootlets of plants. Infringement of processes of moving of moisture in the soil, the accelerated evaporation and the slowed down processes of a filtration and an infiltration, destruction of modular frame, activization of erosive processes is possible. The understanding of these processes will give the chance volume understanding of real influence of running systems of machine-tractor devices on bedrock. Region intensive influence of dual wheels is circumscribed by the top soil layers (0-15 cm. The major feature of influence of dual wheels is absence of an overstocking above critical levels. It is impossible to exclude possible positive influence of moderate inspissations of soil under the influence of dual wheels for growth of agricultural crops and moisture conservation in soil. The cumulative negative effect on soil crossed vehicles traces is probable. The long season of a relaxation of

  17. Assessment of rangeland ecosystem conditions, Salt Creek watershed and Dugout Ranch, southeastern Utah

    Science.gov (United States)

    Bowker, M.A.; Miller, M.E.; Belote, R.T.

    2012-01-01

    Increasingly, dry rangelands are being valued for multiple services beyond their traditional value as a forage production system. Additional ecosystem services include the potential to store carbon in the soil and plant biomass. In addition, dust emissions from rangelands might be considered an ecosystem detriment, the opposite of an ecosystem service. Dust emitted may have far-reaching impacts, for example, reduction of local air quality, as well as altering regional water supplies through effects on snowpack. Using an extensive rangeland monitoring dataset in the greater Canyonlands region (Utah, USA), we developed a method to estimate indices of the provisioning of three ecosystem services (forage production, dust retention, C storage) and one ecosystem property (nativeness), taking into account both ecosystem type and alternative states within that ecosystem type. We also integrated these four indices into a multifunctionality index. Comparing the currently ungrazed Canyonlands National Park watersheds to the adjacent Dugout Ranch pastures, we found clearly higher multifunctionality was attained in the Park, and that this was primarily driven by greater C-storage and better dust retention. It is unlikely to maximize all benefits and minimize all detriments at the same time. Some goods and services may have synergistic interactions; for example, managing for carbon storage will increase plant and biocrust cover likely lowering dust emission. Likewise, some may have antagonistic interactions. For instance, if carbon is consumed as biomass for livestock production, then carbon storage may be reduced. Ultimately our goal should be to quantify the monetary consequences of specific land use practices for multiple ecosystem services and determine the best land use and adaptive management practices for attaining multiple ecosystem services, minimizing economic detriments, and maximizing economic benefits from multi-commodity rangelands. Our technique is the first step

  18. Erosion rates from forests and rangelands following fuel management

    Science.gov (United States)

    William J. Elliot; Peter R. Robichaud; I. Sue Miller

    2007-01-01

    In both forest and rangelands, fuel reduction operations are now common practices. Mechanical thinning followed by prescribed fire is common in forests, while fire is frequently applied to rangelands. Studies at different scales (50 sq m to 389 ha) measure the erosion from fuel management. This presentation compares runoff and erosion from these studies. Plot size has...

  19. Structural and functional diversity in rangelands: integrating different ...

    African Journals Online (AJOL)

    Many rangelands exist as dynamic systems where structural and functional diversity of the community is a function of several interacting factors. Understanding the effects of these factors in rangelands requires an understanding of component functioning at different scales. Integrating the range of levels from ecophysiology ...

  20. Rehabilitation of cheatgrass-infested rangelands: applications and practices

    Science.gov (United States)

    The challenges that land owners and resource managers face when trying to attempt applications and practices when attempting to rehabilitate rangelands infested with cheatgrass (Bromus tectorum) are over-whelming. Simply purchasing seed and spreading it throughout the rangelands is doomed for failu...

  1. Session A2 Rangelands as dynamic systems — Biodiversity ...

    African Journals Online (AJOL)

    Management of rangelands for animal products can reduce, maintain or even increase biodiversity. Loss of biodiversity of plants and animals can lead to decreased productivity and income generation from rangelands or can exacerbate the effects of climatic variability and concomitant increased risks for subsistence and ...

  2. Managing climate change risks in rangeland systems [Chapter 15

    Science.gov (United States)

    Linda A. Joyce; Nadine A. Marshall

    2017-01-01

    The management of rangelands has long involved adapting to climate variability to ensure that economic enterprises remain viable and ecosystems sustainable; climate change brings the potential for change that surpasses the experience of humans within rangeland systems. Adaptation will require an intentionality to address the effects of climate change. Knowledge of...

  3. Rangeland drought: Effects, restoration, and adaptation [Chap. 8

    Science.gov (United States)

    Deborah M. Finch; Rosemary L. Pendleton; Matt C. Reeves; Jeffrey E. Ott; Francis F. Kilkenny; Jack L. Butler; Jacqueline P. Ott; Jeremy R. Pinto; Paulette L. Ford; Justin B. Runyon; Mark A. Rumble; Stanley G. Kitchen

    2016-01-01

    Drought can have severe impacts on rangeland ecosystems in North America. For the purposes of this chapter, rangelands include natural grasslands, savannas, shrublands, many deserts, tundras, alpine communities, marshes, meadows, and woodlands. Drought impacts vary depending on the severity, frequency, duration, and aerial extent of the drought(s); how the land is...

  4. Improving access to livestock markets for sustainable rangeland ...

    African Journals Online (AJOL)

    Productivity of rangelands in Kenya is affected by increasing crop farming especially in more fertile range areas. Among the key factors driving the encroachment of crops on rangelands are the changing opportunities brought about by markets. We hypothesize that the existing market inefficiencies characterizing livestock ...

  5. Influence of soil copper content on the kinetics of thiram adsorption and on thiram leachability from soils.

    Science.gov (United States)

    Filipe, Olga M S; Costa, Carina A E; Vidal, Maria M; Santos, Eduarda B H

    2013-01-01

    This work aimed to assess the influence of soil copper content on the sorption processes of thiram, a fungicide widely used in agriculture, most of the times together with copper. Two different types of studies were performed: (1) desorption studies of thiram with acetonitrile after batch adsorption equilibration, and ageing of the wet soil for a variable period of time; (2) kinetic studies of thiram adsorption performed using the soil in its original form and after fortification with copper ions. In the desorption studies, with the increase of the ageing time, a decrease of the thiram peak and a simultaneous increase of a new peak, assigned to a copper complex, were observed in the chromatograms. This new peak increases sharply until an ageing period of about 4d and then this area is maintained approximately constant until 18 d, the maximum ageing period studied. These results indicate that thiram reacts with copper ions along time giving rise to the formation of relatively persistent copper complexes in soil. Desorption studies with CaCl(2) 0.01 M solution showed that this complex is not extracted. Thus, it is not easily leached to ground and surface waters and copper may contribute to thiram immobilization in soil. The kinetic studies of thiram adsorption were performed in both soils and for two initial thiram concentrations (~7 and 20 mg L(-1)). For the soil fortified with copper the percentage of adsorbed thiram is higher than observed for the original soil at the same initial concentrations and equilibration times and 100% of adsorption is attained in 15 h or 48 h, depending on the thiram initial concentration. Four kinetic equations, the pseudo first- and second-order equations, the Elovich and the intraparticle diffusion equations were selected to fit the kinetic data of the adsorption process of thiram onto both original and fortified soil. The best model to describe the kinetics of thiram adsorption onto the original soil is the intraparticle diffusion

  6. Influence of green manure fertilization on soil enzyme activities and other soil properties

    Directory of Open Access Journals (Sweden)

    Alina Dora SAMUEL

    2007-05-01

    Full Text Available Agricultural practices that improve agricultural sustainability are needed particularly for brown luvic soil. Soil enzyme activities can provide information on how soil management is affecting the processes in soil such as decomposition and nutrient cycling. Soil enzyme activities (actual and potential dehydrogenase, catalase, acid and alkaline phosphatase were determined in the 0–10, 10–20, and 20–30 cm layers of a brown luvic soil submitted to a complex fertilization experiment with different types of green manure. It was found that each activity decreased with increasing sampling depth. It should be emphasized that green-manuring of maize led to a significant increase in each of the five enzymatic activities determined. The enzymatic indicators of soil quality calculated from the values of enzymatic activities showed the order: lupinus + rape + oat > lupinus > vetch + oat + ryegrass > lupinus + oat + vetch > unfertilized plot. This order means that by determination of enzymatic activities valuable information can be obtained regarding fertility status of soils. There were significant correlations of soil enzyme activities with physical properties.

  7. Influence of the soil composition on the effects of benzoxazinoid allelochemicals on two soil nontarget organisms.

    Science.gov (United States)

    Coja, Tamara; Idinger, Jacqueline; Blümel, Sylvia

    2006-02-22

    Seven selected benzoxazinoid allelochemicals and synthetic reference compounds were tested for their lethal and sublethal effects in different field soils and standard soil on Folsomia candida and Poecilus cupreus by applying standard laboratory test procedures. The higher microbial activity in the field soils was most probably responsible for the reduced effects of test compounds on F. candida in the majority of all tests, whereas the higher organic carbon content in field soils was likely the reason for the reduced effects of test substances on P. cupreus.

  8. Influence of Flue Gas Desulfurization Gypsum Amendments on Heavy Metal Distribution in Reclaimed Sodic Soils

    Science.gov (United States)

    Chen, Qun; Wang, Shujuan; Li, Yan; Zhang, Ning; Zhao, Bo; Zhuo, Yuqun; Chen, Changhe

    2015-01-01

    Abstract Although flue gas desulfurization (FGD) gypsum has become an effective soil amendment for sodic soil reclamation, it carries extra heavy metal contamination into the soil environment. The fate of heavy metals introduced by FGD gypsum in sodic or saline–alkali soils is still unclear. This work aims to investigate the effects of FGD gypsum addition on the heavy metal distributions in a sodic soil. Original soil samples were collected from typical sodic land in north China. Soil column leaching tests were conducted to investigate the influence of FGD gypsum addition on the soil properties, especially on distribution profiles of the heavy metals (Pb, Cd, Cr, As, and Hg) in the soil layers. Results showed that pH, electrical conductivity, and exchangeable sodium percentage in amended soils were significantly reduced from 10.2 to 8.46, 1.8 to 0.2 dS/m, and 18.14% to 1.28%, respectively. As and Hg concentrations in the soils were found to be positively correlated with FGD gypsum added. The amount of Hg in the leachate was positively correlated with FGD gypsum application ratio, whereas a negative correlation was observed between the Pb concentration in the leachate and the FGD gypsum ratio. Results revealed that heavy metal concentrations in soils complied well with Environmental Quality Standard for Soils in China (GB15618-1995). This work helps to understand the fate of FGD gypsum-introduced heavy metals in sodic soils and provides a baseline for further environmental risk assessment associated with applying FGD gypsum for sodic soil remediation. PMID:26064038

  9. Influence of Flue Gas Desulfurization Gypsum Amendments on Heavy Metal Distribution in Reclaimed Sodic Soils.

    Science.gov (United States)

    Chen, Qun; Wang, Shujuan; Li, Yan; Zhang, Ning; Zhao, Bo; Zhuo, Yuqun; Chen, Changhe

    2015-06-01

    Although flue gas desulfurization (FGD) gypsum has become an effective soil amendment for sodic soil reclamation, it carries extra heavy metal contamination into the soil environment. The fate of heavy metals introduced by FGD gypsum in sodic or saline-alkali soils is still unclear. This work aims to investigate the effects of FGD gypsum addition on the heavy metal distributions in a sodic soil. Original soil samples were collected from typical sodic land in north China. Soil column leaching tests were conducted to investigate the influence of FGD gypsum addition on the soil properties, especially on distribution profiles of the heavy metals (Pb, Cd, Cr, As, and Hg) in the soil layers. Results showed that pH, electrical conductivity, and exchangeable sodium percentage in amended soils were significantly reduced from 10.2 to 8.46, 1.8 to 0.2 dS/m, and 18.14% to 1.28%, respectively. As and Hg concentrations in the soils were found to be positively correlated with FGD gypsum added. The amount of Hg in the leachate was positively correlated with FGD gypsum application ratio, whereas a negative correlation was observed between the Pb concentration in the leachate and the FGD gypsum ratio. Results revealed that heavy metal concentrations in soils complied well with Environmental Quality Standard for Soils in China (GB15618-1995). This work helps to understand the fate of FGD gypsum-introduced heavy metals in sodic soils and provides a baseline for further environmental risk assessment associated with applying FGD gypsum for sodic soil remediation.

  10. Soil microbial communities: Influence of geographic location and hydrocarbon pollutants

    CSIR Research Space (South Africa)

    Maila, MP

    2006-02-01

    Full Text Available The importance and relevance of the geographical origin of the soil sample and the hydrocarbons in determining the functional or species diversity within different bacterial communities was evaluated using the community level physiological profiles...

  11. Kinetics of cadmium release from soils as influenced by organic acids: Implication in cadmium availability

    Energy Technology Data Exchange (ETDEWEB)

    Krishnamurti, G.S.R.; Cieslinski, G.; Huang, P.M.; Van Rees, K.C.J. [Univ. of Saskatchewan (Canada)

    1997-01-01

    The low-molecular-weight organic acids (LMWOAs) secreted by plant roots modify the mobility of Cd through formation of soluble complexes in the soil rhizosphere; the kinetics of Cd release as influenced by organic acids and its impact on Cd bioaccumulation remains to be established. The influence of LMWOAs (10{sup -3} and 10{sup -2} M), viz., acetic, citric, oxalic, fumaric, and succinic acids, which are present in the soil rhizosphere, on the kinetics of Cd release from selected soils (Luseland, Waitville, and Jedbergh) of Saskatchewan, Canada, was investigated at 25{degrees}C and at an ionic strength of 0.1 M NaNO{sub 3}. It was observed that the Cd release from the soils increased initially up to a reaction period of about 2 h and then slowly decreased with time. With time, the LMWOAs were apparently microbially degraded and the soil solution Cd{sup 2+}, which was transformed from the Cd-LMWOA complexes by microbial degradation, was adsorbed onto the negatively charged soil particles. Increasing amounts of Cd were released form the soils to the soil solution with the renewal of LMWOAs after every 2 h. The short-term (reaction period of 0.25 to 1 h) kinetics of Cd release from the soils was described by a parabolic diffusion kinetic model. The overall diffusion coefficient of the Cd release form the soil and the Cd released by the renewal of LMWOAs followed the same trend as the Cd availability index of the soils: Luseland >> Waitville > Jedbergh. Thus, the results presented in this investigation indicate the importance of the kinetics of the Cd release from the soils by the LMWOAs excreted by root exudates in understanding the availability of soil Cd. 46 refs., 2 figs., 6 tabs.

  12. Sustainable rangeland management, economic growth, and a cautious role for the SRM

    Science.gov (United States)

    Interest in the art and science of rangeland management increased dramatically during the 20th century and it was out of this interest that the profession of rangeland management was born. As public interest in rangeland management grew, so did the number, breadth, and depth of rangeland management ...

  13. An Integrated Social, Economic, and Ecologic Conceptual (ISEEC) framework for considering rangeland sustainability

    Science.gov (United States)

    William E. Fox; Daniel W. McCollum; John E. Mitchell; Louis E. Swanson; Urs P. Kreuter; John A. Tanaka; Gary R. Evans; H. Theodore Heintz; Robert P. Breckenridge; Paul H. Geissler

    2009-01-01

    Currently, there is no standard method to assess the complex systems in rangeland ecosystems. Decision makers need baselines to create a common language of current rangeland conditions and standards for continued rangeland assessment. The Sustainable Rangeland Roundtable (SRR), a group of private and public organizations and agencies, has created a forum to discuss...

  14. Criterion II: Indicators for conservation and maintenance of plant and animal resources on rangelands (Chapter 3)

    Science.gov (United States)

    Linda A. Joyce; William Fox; Paul Geissler; Rodney Heitschmidt; Lori Hidinger; Duncan Patten; John Spence; Laurence L. Strong; Robert Unnasch; Robert A. Washington-Allen

    2010-01-01

    Five criteria were established by the Sustainable Rangelands Roundtable to be used to assess rangeland sustainability on a national scale. One of those criteria is the conservation and maintenance of plant and animal resources. Within this criterion, 10 indicators were developed through the expert opinions of rangeland scientists, rangeland management agency personnel...

  15. Factors influencing the soil-air partitioning and the strength of soils as a secondary source of polychlorinated biphenyls to the atmosphere.

    Science.gov (United States)

    Cabrerizo, Ana; Dachs, Jordi; Moeckel, Claudia; Ojeda, María-José; Caballero, Gemma; Barceló, Damià; Jones, Kevin C

    2011-06-01

    Soils are a major reservoir of persistent organic pollutants, and soil-air partitioning and exchange are key processes controlling the atmospheric concentrations and regional fate of pollutants. Here, we report and discuss the concentrations of polychlorinated biphenyls (PCBs) in soils, their measured fugacities in soil, the soil-air partition coefficients (K(SA)) and soil-air fugacity gradients in rural background areas of N-NE Spain and N-NW England. Four sampling campaigns were carried out to assess seasonal and daily variability and differences between sampling sites. K(SA) values were significantly dependent on soil temperature and soil organic matter quantity, and to a minor extent organic matter type. All the PCB congeners in the soil are close to equilibrium with the atmosphere at rural Ebro sites, but soil fugacities tend to be higher than ambient air fugacities in early and late summer, consistent with the influence of temperature on soil-air partitioning. Therefore, during warm periods, soils increment their strength as secondary sources to the atmosphere. The mixture of PCBs found in the atmosphere is clearly strongly influenced by the mixture of PCBs which escape from soil, with significant correlations between them (R(2) ranging between 0.35 and 0.74 and p-level air and soil concentrations, but it is not possible to elucidate the importance of these soils as secondary sources yet, and presumably there are still significant primary sources to the regional/global environment.

  16. Climate change effects on rangelands and rangeland management: Affirming the need for monitoring

    Science.gov (United States)

    Daniel W. Mccollum; John A. Tanaka; Jack A. Morgan; John E. Mitchell; William E. Fox; Kristie A. Maczko; Lori Hidinger; Clifford S. Duke; Urs P. Kreuter

    2017-01-01

    Uncertainty as to the extent and magnitude of changes in conditions that might occur due to climate change poses a problem for land and resource managers as they seek to adapt to changes and mitigate effects of climate variability. We illustrate using scenarios of projected future conditions on rangelands in the Northern Great Plains and Desert Southwest of the United...

  17. How contamination sources and soil properties can influence the Cd and Pb bioavailability to snails.

    Science.gov (United States)

    Pauget, Benjamin; Gimbert, Frédéric; Coeurdassier, Mickael; Druart, Coline; Crini, Nadia; de Vaufleury, Annette

    2016-02-01

    To better understand the fate of metals in the environment, numerous parameters must be studied, such as the soil properties and the different sources of contamination for the organisms. Among bioindicators of soil quality, the garden snail (Cantareus aspersus) integrates multiple sources (e.g. soil, plant) and routes (e.g. digestive, cutaneous) of contamination. However, the contribution of each source on metal bioavailability and how soil properties influence these contributions have never been studied when considering the dynamic process of bioavailability. Using accumulation kinetics, this study showed that the main assimilation source of Cd was lettuce (68%), whereas the main source of Pb was the soil (90%). The plant contribution increased in response to a 2-unit soil pH decrease. Unexpectedly, an increase in the soil contribution to metal assimilation accompanied an increase in the organic matter (OM) content of the soil. For both metals, no significant excretion and influence of source on excretion have been modelled either during exposure or depuration. This study highlights how the contribution of different sources to metal bioavailability changes based on changes in soil parameters, such as pH and OM, and the complexity of the processes that modulate metal bioavailability.

  18. Influences of space, soil, nematodes and plants on microbial community composition of chalk grassland soils

    NARCIS (Netherlands)

    Yergeau, E.; Bezemer, T.M.; Hedlund, K.; Mortimer, S.R.; Kowalchuk, G.A.; Van der Putten, W.H.

    2010-01-01

    Microbial communities respond to a variety of environmental factors related to resources (e.g. plant and soil organic matter), habitat (e.g. soil characteristics) and predation (e.g. nematodes, protozoa and viruses). However, the relative contribution of these factors on microbial community

  19. Influence of soil moisture content on surface albedo and soil thermal ...

    Indian Academy of Sciences (India)

    ture on the moraine of the Zongo glacier (Bolivia): Impli- cations for land surface modeling; Geophys. Res. Lett. 36. L02405, doi: 10.1029/2008GL036377. Guan X D, Huang J P, Guo N, Bi J R and Wang G Y. 2009 Variability of soil moisture and its relationship with surface albedo and soil thermal parameters over the Loess.

  20. Soil enzyme dynamics in chlorpyrifos-treated soils under the influence of earthworms.

    Science.gov (United States)

    Sanchez-Hernandez, Juan C; Notario Del Pino, J; Capowiez, Yvan; Mazzia, Christophe; Rault, Magali

    2018-01-15

    Earthworms contribute, directly and indirectly, to contaminant biodegradation. However, most of bioremediation studies using these annelids focus on pollutant dissipation, thus disregarding the health status of the organism implied in bioremediation as well as the recovery of indicators of soil quality. A microcosm study was performed using Lumbricus terrestris to determine whether earthworm density (2 or 4individuals/kg wet soil) and the time of exposure (1, 2, 6, 12, and 18wk) could affect chlorpyrifos persistence in soil initially treated with 20mg active ingredientkg(-1) wet soil. Additionally, selected earthworm biomarkers and soil enzyme activities were measured as indicators of earthworm health and soil quality, respectively. After an 18-wk incubation period, no earthworm was killed by the pesticide, but clear signs of severe intoxication were detected, i.e., 90% inhibition in muscle acetylcholinesterase and carboxylesterase (CbE) activities. Unexpectedly, the earthworm density had no significant impact on chlorpyrifos dissipation rate, for which the measured half-life ranged between 30.3d (control soils) and 44.5d (low earthworm density) or 36.7d (high earthworm density). The dynamic response of several soil enzymes to chlorpyrifos exposure was examined calculating the geometric mean and the treated-soil quality index, which are common enzyme-based indexes of microbial functional diversity. Both indexes showed a significant and linear increase of the global enzyme response after 6wk of chlorpyrifos treatment in the presence of earthworms. Examination of individual enzymes revealed that soil CbE activity could decrease chlorpyrifos-oxon impact upon the rest of enzyme activities. Although L. terrestris was found not to accelerate chlorpyrifos dissipation, a significant increase in the activity of soil enzyme activities was achieved compared with earthworm-free, chlorpyrifos-treated soils. Therefore, the inoculation of organophosphorus-contaminated soils with

  1. The influence of land use on soil organic carbon and nitrogen content and redox potential

    DEFF Research Database (Denmark)

    Kusliene, Gedrime

    2010-01-01

    different farming systems (conventional and organic) as well as abandoned lands. We choose the plants of two botanical species (Poaceae and Fabaceae) in organic and conventional farming systems as well as abandoned lands. Experimental results show that the best soil organic matter status according...... to the investigated indexes is in the soils of conventional and orgaic farming systems occupied with mixtures of Poaceae and Fabaceae and the worst - in the soils of abandoned Poaceae meadowa. In the abandoned lands, Fabaceae (galega) had better influence on soil organic matter status than Poaceae.......The aim of the research was to evaluate organic matter status in the soil according to the organic carbon content, total and mineral nitrogen amounts, carbon to nitrogen (C:N) ratio and redox potential depending on land usage and plant spieces. Soil samples were taken from the fields under...

  2. Influence of wheat ash on the MCPA immobilization in agricultural soils.

    Science.gov (United States)

    Hiller, E; Fargasová, A; Zemanová, L; Bartal, M

    2008-09-01

    Burning of crop residues in the fields is a routine post-harvest practice and results in accumulation of ashes in soils. Recent studies have shown that the ashes may significantly contribute to the herbicide sorption in soils. This study was conducted to evaluate the potential role of wheat ash in immobilization of anionic herbicide MCPA in soils. The results showed that wheat ash is highly effective sorbent for herbicide MCPA. Amendment of Fluvi-Gleyic Phaeozem and Eutric Regosol with 1% wheat ash caused a 8-fold and 16-fold increase in MCPA sorption, respectively. Desorption of MCPA was also influenced by wheat ash in soils. The addition of wheat ash to both soils increased the resistant fraction to desorption up to 80%. Generally, the field burning of crop residues appears to increase the sorption of pesticides in agricultural soils and decrease their leaching.

  3. Zinc movement in sewage-sludge-treated soils as influenced by soil properties, irrigation water quality, and soil moisture level

    Science.gov (United States)

    Welch, J.E.; Lund, L.J.

    1989-01-01

    A soil column study was conducted to assess the movement of Zn in sewage-sludge-amended soils. Varables investigated were soil properties, irrigation water quality, and soil moisture level. Bulk samples of the surface layer of six soil series were packed into columns, 10.2 cm in diameter and 110 cm in length. An anaerobically digested municipal sewage sludge was incorporated into the top 20 cm of each column at a rate of 300 mg ha-1. The columns were maintained at moisture levels of saturation and unsaturation and were leached with two waters of different quality. At the termination of leaching, the columns were cut open and the soil was sectioned and analyzed. Zinc movement was evaluated by mass balance accounting and correlation and regression analysis. Zinc movement in the unsaturated columns ranged from 3 to 30 cm, with a mean of 10 cm. The difference in irrigation water quality did not have an effect on Zn movement. Most of the Zn applied to the unsaturated columns remained in the sludge-amended soil layer (96.1 to 99.6%, with a mean of 98.1%). The major portion of Zn leached from the sludge-amended soil layer accumulated in the 0- to 3-cm depth (35.7 to 100%, with a mean of 73.6%). The mean final soil pH values decreased in the order: saturated columns = sludge-amended soil layer > untreated soils > unsaturated columns. Total Zn leached from the sludge-amended soil layer was correlated negatively at P = 0.001 with final pH (r = -0.85). Depth of Zn movement was correlated negatively at P = 0.001 with final pH (r = -0.91). Multiple linear regression analysis showed that the final pH accounted for 72% of the variation in the total amounts of Zn leached from the sludge-amended soil layer of the unsaturated columns and accounted for 82% of the variation in the depth of Zn movement among the unsaturated columns. A significant correlation was not found between Zn and organic carbon in soil solutions, but a negative correlation significant at P = 0.001 was found

  4. Elevated carbon dioxide: impacts on soil and plant water relations

    National Research Council Canada - National Science Library

    Kirkham, M. B

    2011-01-01

    .... Focusing on this critical issue, Elevated Carbon Dioxide: Impacts on Soil and Plant Water Relations presents research conducted on field-grown sorghum, winter wheat, and rangeland plants under elevated CO2...

  5. Influence of vermicomposting on solid wastes decomposition kinetics in soils*

    Science.gov (United States)

    Nourbakhsh, Farshid

    2007-01-01

    The effect of vermicomposting on kinetic behavior of the products is not well recognized. An incubation study was conducted to investigate C mineralization kinetics of cow manure, sugarcane filter cake and their vermicomposts. Two different soils were treated with the four solid wastes at a rate of 0.5 g solid waste C per kg soil with three replications. Soils were incubated for 56 d. The CO2-C respired was monitored periodically and a first-order kinetic model was used to calculate the kinetic parameters of C mineralization. Results indicated that the percentage of C mineralized during the incubation period ranged from 31.9% to 41.8% and 55.9% to 73.4% in the calcareous and acidic soils, respectively. The potentially mineralizable C (C 0) of the treated soils was lower in the solid waste composts compared to their starting materials. Overall, it can be concluded that decomposable fraction of solid wastes has decreased due to vermicomposting. PMID:17910115

  6. Influence of the soil sealing on the geoaccumulation index of heavy metals and various pollution factors.

    Science.gov (United States)

    Charzyński, Przemysław; Plak, Andrzej; Hanaka, Agnieszka

    2017-02-01

    Soil sealing belongs to the most destructive and damaging processes to the soil environment. Soil sealing interrupts or greatly restricts the exchange of matter and energy between the biosphere, hydrosphere, and atmosphere and the soil environment. The aim of this study was to compare the content of heavy metals (Cd, Cr, Cu, Hg, Fe, Ni, Pb, Zn) of Ekranic Technosols by applying indicators such as geoaccumulation index (I geo), enrichment factor (EF), and pollution load index (PLI), which allowed to determine quantitatively the impact of the soil sealing degree on the content of heavy metals and to distinguish natural from anthropogenic sources of origin of heavy metals. In general, 42 soils from different parts of the city of Toruń (NW Poland) were sampled and divided into three groups according to the degree of soil sealing: completely sealed with asphalt or concrete (A), semi-permeable (partially sealed with cobblestones and concrete paving slabs (B)), and reference (non-sealed) (C). The results indicate that the artificial sealing in urban areas slightly affects the content of heavy metals in soils. However, based on PLI, I geo, and EF, it was found that the sealing has influence on soil properties and unsealed soil is the most exposed to the accumulation of pollutants.

  7. Soil evolution in spruce forest ecosystems: role and influence of humus studied by morphological approach

    Directory of Open Access Journals (Sweden)

    Chersich S

    2007-01-01

    Full Text Available In order to understand the role and the mutual influences of humus and soil in alpine spruce forest ecosystems we studied and classified 7 soil - humic profiles on the 4 main forestry dynamics: open canopy, regeneration, young stand, tree stage. We studied the role of humification process in the pedologic process involving soils and vegetations studing humic and soil horizons. Study sites are located at an altitude of 1740 m a.s.l near Pellizzano (TN, and facing to the North. The parent soil material is predominantly composed of morenic sediments, probably from Cevedale glacier lying on a substrate of tonalite from Presanella (Adamello Tertiary pluton. The soil temperature regime is frigid, while the moisture regime is udic. The characteristics observed in field were correlated with classical chemical and physical soil analyses (MIPAF 2000. In order to discriminate the dominant soil forming process, the soils were described and classified in each site according to the World Reference Base (FAO-ISRIC-ISSS 1998. Humus was described and classified using the morphological-genetic approach (Jabiol et al. 1995. The main humus forms are acid and they are for the greater part Dysmoder on PODZOLS. The main pedogenetic processes is the podzolization, locally there are also hydromorphic processes. We associate a definite humus form with a pedological process at a particular step of the forest evolution. We concluded thath the soil study for a correct pedological interpretation must take count of the characteristics of the humic epipedon.

  8. Influence of cracking clays on satellite estimated and model simulated soil moisture

    Directory of Open Access Journals (Sweden)

    Y. Y. Liu

    2010-06-01

    Full Text Available Vertisols are clay soils that are common in the monsoonal and dry warm regions of the world. One of the characteristics of these soil types is to form deep cracks during periods of extended dry, resulting in significant variation of the soil and hydrologic properties. Understanding the influence of these varying soil properties on the hydrological behavior of the system is of considerable interest, particularly in the retrieval or simulation of soil moisture. In this study we compare surface soil moisture (θ in m3 m−3 retrievals from AMSR-E using the VUA-NASA (Vrije Universiteit Amsterdam in collaboration with NASA algorithm with simulations from the Community Land Model (CLM over vertisol regions of mainland Australia. For the three-year period examined here (2003–2005, both products display reasonable agreement during wet periods. During dry periods however, AMSR-E retrieved near surface soil moisture falls below values for surrounding non-clay soils, while CLM simulations are higher. CLM θ are also higher than AMSR-E and their difference keeps increasing throughout these dry periods. To identify the possible causes for these discrepancies, the impacts of land use, topography, soil properties and surface temperature used in the AMSR-E algorithm, together with vegetation density and rainfall patterns, were investigated. However these do not explain the observed θ responses. Qualitative analysis of the retrieval model suggests that the most likely reason for the low AMSR-E θ is the increase in soil porosity and surface roughness resulting from cracking of the soil. To quantitatively identify the role of each factor, more in situ measurements of soil properties that can represent different stages of cracking need to be collected. CLM does not simulate the behavior of cracking soils, including the additional loss of moisture from the soil continuum during drying and the infiltration into cracks during rainfall events

  9. The influence of plant communities on postagrogenic soils in the middle taiga zone.

    Science.gov (United States)

    Churilin, Nikita; Churilina, Alexandra; Chizhikova, Natalia; Varlamov, Evgeny

    2016-04-01

    decreases with crown density, therefore clay doesn't migrate to the underlying horizons in the soil. Over time, acid aqueous solution can influence on process of clay fraction redistribution, so it explains the reduction of clay content in the old spruce forest and well-defined albic horizon. The results of chemical analyses showed that pH of these soils varies between 3 and 4. In all soils we can see illuvial accumulation of P2O5, exchangeable bases, K2O, Fe2O3. It was also shown that carbonates are present in horizons close to the subsoil, which content is less than 1%.

  10. Influence of soil parameters on depth of oil waste penetration

    Directory of Open Access Journals (Sweden)

    Rychlicki Stanislaw

    2004-09-01

    Full Text Available A measurement post for testing propagation of hydrocarbon contamination in a model of a near-surface soil layer and its remediation, are characterized in the paper. Generalized results of laboratory observations require meeting similarity criteria of the laboratory and actual processes. These requirements were used when designing the measurement post. A successful attempt to match a theoretical model describing oil products filtration necessitates certain conditions, e.g. homogeneity of the physical model of soil and characteristic of the course of the analyzed processes.

  11. Topsoil and subsoil properties influence phosphorus leaching from four agricultural soils.

    Science.gov (United States)

    Andersson, Helena; Bergström, Lars; Djodjic, Faruk; Ulén, Barbro; Kirchmann, Holger

    2013-01-01

    Eutrophication, a major problem in many fresh and brackish waters, is largely caused by nonpoint-source pollution by P from agricultural soils. This lysimeter study examined the influence of P content, physical properties, and sorption characteristics in topsoil and subsoil on P leaching measured during 21 mo in 1-m-long, undisturbed soil columns of two clay and two sandy soils. Total P losses during the period varied between 0.65 and 7.40 kg ha. Dissolved reactive P was the dominant form in leachate from the sandy soils and one clay soil, varying from 48 to 76%. Particulate P dominated in leachate from the other clay soil, where low pH (5.2) in the subsoil decreased aggregate stability and thereby probably increased the dispersion of clay particles. Phosphorus leaching was small from soils with high P sorption index (PSI) and low P saturation (topsoil was high, and large from a soil with low sorption capacity and high P saturation (>35% of PSI) in the profile. High sorption capacity in the subsoil was more important for P leaching in sandy soils than in clay soils with macropore flow, where the effect of high sorption capacity was reduced due to less interaction between percolating water and the soil matrix. The results suggest that P leaching is greatly affected by subsoil properties and that topsoil studies, which dominate current research, are insufficient for assessing P leaching in many soils. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  12. Influences of Different Halophyte Vegetation on Soil Microbial Community at Temperate Salt Marsh.

    Science.gov (United States)

    Chaudhary, Doongar R; Kim, Jinhyun; Kang, Hojeong

    2017-10-06

    Salt marshes are transitional zone between terrestrial and aquatic ecosystems, occupied mainly by halophytic vegetation which provides numerous ecological services to coastal ecosystem. Halophyte-associated microbial community plays an important role in the adaptation of plants to adverse condition and also affected habitat characteristics. To explore the relationship between halophytes and soil microbial community, we studied the soil enzyme activities, soil microbial community structure, and functional gene abundance in halophytes- (Carex scabrifolia, Phragmites australis, and Suaeda japonica) covered and un-vegetated (mud flat) soils at Suncheon Bay, South Korea. Higher concentrations of total, Gram-positive, Gram-negative, total bacterial, and actinomycetes PLFAs (phospholipid fatty acids) were observed in the soil underneath the halophytes compared with mud flat soil and were highest in Carex soil. Halophyte-covered soils had different microbial community composition due to higher abundance of Gram-negative bacteria than mud flat soil. Similar to PLFA concentrations, the increased activities of β-glucosidase, cellulase, phosphatase, and sulfatase enzymes were observed under halophyte soil compared to mud flat soil and Carex exhibited highest activities. The abundance of archaeal 16S rRNA, fungal ITS, and denitrifying genes (nirK, nirS, and nosZ) were not influenced by the halophytes. Abundance bacterial 16S rRNA and dissimilatory (bi)sulfite (dsrA) genes were highest in Carex-covered soil. The abundance of functional genes involved in methane cycle (mcrA and pmoA) was not affected by the halophytes. However, the ratios of mcrA/pmoA and mcrA/dsrA increased in halophyte-covered soils which indicate higher methanogenesis activities. The finding of the study also suggests that halophytes had increased the microbial and enzyme activities, and played a pivotal role in shaping microbial community structure.

  13. Decisive key-factors influencing farm households' soil and water conservation investments

    NARCIS (Netherlands)

    Kessler, A.

    2006-01-01

    In the inter-Andean valleys of Bolivia decisive key-factors influencing farm households' soil and water conservation investments were determined. The household's progressiveness most influences the decision how much to invest; dynamic and responsible families are among the first. Economic stratum is

  14. Pine forest and grassland differently influence the response of soil microbial communities to metal contamination.

    Science.gov (United States)

    Stefanowicz, Anna M; Niklińska, Maria; Kapusta, Paweł; Szarek-Łukaszewska, Grażyna

    2010-11-15

    Metal pollution can affect soil microbial communities, and vegetation potentially influences this relationship. It can, for example, modify the toxicity of metal to soil microbes by controlling its input to the ground or by altering soil physicochemical properties. This study examined metal effects on soil respiration, potentially active microbial biomass (SIR) and catabolic abilities of culturable heterotrophic bacterial communities (Biolog GN) in pine forest and grassland ecosystems developed on soils contaminated with Zn, Pb and Cd. In samples from non-forested areas we found that metal pollution reduced the microbial biomass and functional diversity of bacteria, while increasing the metabolic quotient. In samples from pine forests we found no relationship between metal pollution and microbial parameters. Metals induced changes in soil respiration neither in forest nor in grassland sites. Generally, microbial performance was determined predominantly by soil physicochemical properties (nutrient content, acidity, contamination level). Vegetation type seemed a minor but important factor influencing microbial communities. More work is needed to determine why even relatively high metal concentrations do not significantly affect microbial communities in forest soils. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. Land-use changes influence soil bacterial communities in a meadow grassland in Northeast China

    Science.gov (United States)

    Cao, Chengyou; Zhang, Ying; Qian, Wei; Liang, Caiping; Wang, Congmin; Tao, Shuang

    2017-10-01

    The conversion of natural grassland into agricultural fields is an intensive anthropogenic perturbation commonly occurring in semiarid regions, and this perturbation strongly affects soil microbiota. In this study, the influences of land-use conversion on the soil properties and bacterial communities in the Horqin Grasslands in Northeast China were assessed. This study aimed to investigate (1) how the abundances of soil bacteria changed across land-use types, (2) how the structure of the soil bacterial community was altered in each land-use type, and (3) how these variations were correlated with soil physical and chemical properties. Variations in the diversities and compositions of bacterial communities and the relative abundances of dominant taxa were detected in four distinct land-use systems, namely, natural meadow grassland, paddy field, upland field, and poplar plantation, through the high-throughput Illumina MiSeq sequencing technique. The results indicated that land-use changes primarily affected the soil physical and chemical properties and bacterial community structure. Soil properties, namely, organic matter, pH, total N, total P, available N and P, and microbial biomass C, N, and P, influenced the bacterial community structure. The dominant phyla and genera were almost the same among the land-use types, but their relative abundances were significantly different. The effects of land-use changes on the structure of soil bacterial communities were more quantitative than qualitative.

  16. Influence of thickness and position of the individual layer on the permeability of the stratified soil

    Directory of Open Access Journals (Sweden)

    Priyank Gupta

    2016-09-01

    Full Text Available Flow of fluid through a porous media is a very important phenomenon that occurs largely in many physical situations such as flow in an aquifer, flow through filters for water purification in sewage treatment plant, flow in packed bed chemical reactor, etc. Permeability is a characteristic parameter for a porous media and it tells about the ease with which water flows through the interconnected voids. Since it directly influences the rate of flow of water in a soil, it has a decisive effect on problems involving excavations of open cuts in sand below water table, seepage through embankment dams, sub-grade drainage, rate of consolidation of compressible soil, etc. In a soil profile, each layer may have its own properties which may or may not be same as compared to the layer below or above it. The relative position and the thickness of a soil layer of a stratified soil system are some of the important parameters which affect the permeability of the composite soil layer. In the present study the experiments have, therefore, been conducted to investigate the influence of position and thickness of the individual layer on the permeability of the composite soil. It has been found that thickness of end layer has significant effect on the permeability of stratified soils.

  17. The Influence of Soil Chemical Factors on In Situ Bioremediation of Soil Contamination

    Energy Technology Data Exchange (ETDEWEB)

    Breedveld, Gijs D.

    1997-12-31

    Mineral oil is the major energy source in Western society. Production, transport and distribution of oil and oil products cause serious contamination problems of water, air and soil. The present thesis studies the natural biodegradation processes in the soil environment which can remove contamination by oil products and creosote. The main physical/chemical processes determining the distribution of organic contaminants between the soil solid, aqueous and vapour phase are discussed. Then a short introduction to soil microbiology and environmental factors important for biodegradation is given. There is a discussion of engineered and natural bioremediation methods and the problems related to scaling up laboratory experiments to field scale remediation. Bioremediation will seldom remove the contaminants completely; a residue remains. Factors affecting the level of residual contamination and the consequences for contaminant availability are discussed. Finally, the main findings of the work are summarized and recommendations for further research are given. 111 refs., 41 figs., 19 tabs.

  18. Evaluation of soil microbial communities as influenced by crude oil ...

    African Journals Online (AJOL)

    sunny t

    2015-05-13

    May 13, 2015 ... A wholiststic understanding of soil microbial communities have been broadly defined by biochemical- based techniques and molecular-based techniques (Kirk et al., 2004; Abbasi et al., 2010). Biochemical methods accounted for their phenotypic expressions (e.g., respiration, enzymes and catabolic ...

  19. Influence of soil organisms on accuracy predicting leaf litter ...

    African Journals Online (AJOL)

    To use Near Infrared Spectroscopy (NIRS) in the study of litter decomposition in field conditions, it's essential to know the relative role of different environmental factors that may affect its accuracy. This study attempts to determine the effects of soil organisms on direct predicting by NIRS, the stage of litter decomposition, ...

  20. Environmental study of heavy metals influence on soil and Tansy ...

    African Journals Online (AJOL)

    ... work was to define the correlation between heavy metal (mercury, lead, cadmium, chrome and nickel) concentration changes (in soil, leaf, stem, root and essential oil in Tansy) and type and distance from source pollution. The concentration was monitored on different locations: 1) Chemical industry panevo (with accident ...

  1. Soil nutrients influence spatial distributions of tropical tree species.

    Science.gov (United States)

    John, Robert; Dalling, James W; Harms, Kyle E; Yavitt, Joseph B; Stallard, Robert F; Mirabello, Matthew; Hubbell, Stephen P; Valencia, Renato; Navarrete, Hugo; Vallejo, Martha; Foster, Robin B

    2007-01-16

    The importance of niche vs. neutral assembly mechanisms in structuring tropical tree communities remains an important unsettled question in community ecology [Bell G (2005) Ecology 86:1757-1770]. There is ample evidence that species distributions are determined by soils and habitat factors at landscape (Yasuni), and Panama (Barro Colorado Island). Using spatial distribution maps of >0.5 million individual trees of 1,400 species and 10 essential plant nutrients, we used Monte Carlo simulations of species distributions to test plant-soil associations against null expectations based on dispersal assembly. We found that the spatial distributions of 36-51% of tree species at these sites show strong associations to soil nutrient distributions. Neutral dispersal assembly cannot account for these plant-soil associations or the observed niche breadths of these species. These results indicate that belowground resource availability plays an important role in the assembly of tropical tree communities at local scales and provide the basis for future investigations on the mechanisms of resource competition among tropical tree species.

  2. Influence of vermicompost on soil chemical and physical properties ...

    African Journals Online (AJOL)

    In this study, the effects of vermicompost on soil chemical and physical properties was evaluated in tomato (Lycopersicum esculentum var Super Beta) field. The experiment was arranged in a randomized complete block design with four replications. Different amounts of vermicompost (0, 5, 10, 15 t ha-1) were incorporated ...

  3. Influence of soil type differences on the distribution of DTPA ...

    African Journals Online (AJOL)

    This study determined the effects of the application of industrial liquid waste from a textile factory on the distribution of DTPA extractable metals in a Pelli-Eutric Vertisol and an Eutric Fluvisol at Akaki in Ethiopia, classified according to the FAO-UNESCO Soil Classification System. The Fluvisol is slightly basic on the surface ...

  4. Influence of microtopography on soil chemistry and understory riparian vegetation

    Science.gov (United States)

    Irene M. Unger; Rose-Marie Muzika

    2008-01-01

    The success of riparian forest restoration efforts depends in part on an understanding of the relationship between soil characteristics and vegetation patterns and how these change with site conditions. To examine these relationships for floodplains in northern Missouri, we chose three unchannelized streams as study areas. A sampling grid was established at two plots...

  5. Influence of salinity on soil chemical properties and surrounding ...

    African Journals Online (AJOL)

    The exchangeable sodium percentage (ESP), cation exchange capacity (CEC) and sodium adsorption ratio (SAR) were calculated. No plant was found growing on the salt mining site (SMS) unlike the control site (CTS) which has a little diversity of plants. The soil organic carbon, organic magnesium, total nitrogen and ...

  6. Evaluation of soil microbial communities as influenced by crude oil ...

    African Journals Online (AJOL)

    Impact of petroleum pollution in a vulnerable Niger Delta ecosystem was investigated to assess interactions in a first-generation phytoremediation site of a crude oil freshly-spilled agricultural soil. Community-level approach for assessing patterns of sole carbon-source utilization by mixed microbial samples was employed to ...

  7. Influence of Tillage and Mulch on Soil Physical Properties and ...

    African Journals Online (AJOL)

    User

    Abstract. Zero tillage along with application of mulch is an important strategy for soil conservation which maintains sustainability of agricultural system. A randomized complete block design in a split plot arrangement was used with four tillage methods [conventional tillage, (CT); deep tillage, (DT); zero tillage with zone disc ...

  8. Influence of transient flooding on steel strip reinforced soil walls

    National Research Council Canada - National Science Library

    Miyata, Yoshihisa; Bathurst, Richard J; Otani, Yoshinori; Ohta, Hitoshi; Miyatake, Hiroaki

    2015-01-01

    ... for transient flooding ( Kuwano et al., 2014 ). In an earlier related study, Miyata et al. (2010) described a series of full-scale laboratory tests that involved the flooding and rapid drawdown loading of three 6 m-high instrumented steel multi-anchor walls (MAWs). Each wall was nominally identical but was constructed with a different backfill soil...

  9. Influence of pharmaceutical effluent on some soil chemical ...

    African Journals Online (AJOL)

    There were no drastic changes in the soil texture class. Also the nutrient uptake by the maize plant, the collar girth, leaf area were enhanced while the plant height as well as the number of leaves were depressed compared to control. The chlorophyll content of the maize plant however, was enhanced at low effluent ...

  10. Performance of Cochorus olitorius as influenced by soil type and ...

    African Journals Online (AJOL)

    An experiment was conducted in Yewa North Local Government Area, Ogun State to evaluate the effect of four soil types (loamy, sand, clay and silt) amended with poultry manure (PM), plant manure (PLM), sheep/goat manure (SGM) and NPK on performance of Cochorus olitorius. It was a factorial experiment in completely ...

  11. Influence of Internal Temperatures of Soil on Soil Drying Curves by the Microwave Heating

    OpenAIRE

    UEDA, Kazuo

    1995-01-01

    The development of the method of quick determination of water content by microwaves has being watched with keenest interest by soil mechanics and foundation engineers. A certain number of experimental works have made it clear that the microwave oven functions well for the present compared to JIS method. In detailed observation, usually it was observed in a conventional oven that soil sample with low wet density required shorter than the time for drying of the one with high wet density. But, d...

  12. Influence of soil temperature on Globodera rostochiensis and Globodera pallida

    Directory of Open Access Journals (Sweden)

    Agata KACZMAREK

    2015-01-01

    Full Text Available Relationships between soil temperatures and the potato cyst nematode (PCN life cycle and population multiplication were investigated to understand the risks to potato crops from PCN in relation to increasing soil temperatures associated with climate change, and to support development of the United Kingdom Potato Council`s PCN management model. The initial (hatching part of the PCN life cycle was examined for both Globodera rostochiensis and G. pallida over a range of temperatures, and the responses are then considered in relation to actual soil temperatures during the potato growing season in different sites in the United Kingdom. Hatching was stimulated by potato root diffusate over a temperature range from 5–29ºC and was monitored for 5 weeks. The greatest cumulative percentage hatch of second stage juveniles (J2 occurred between 15 and 27ºC for G. rostochiensis and 13–25ºC for G. pallida. Globodera rostochiensis hatched more quickly and had a delayed hatch at ≥25ºC while G. pallida was more efficient at these higher temperatures. From these observations, it is likely that climate change, and associated increases in soil temperatures, will result in increased rates and amounts of hatching for both species, leading to increased population levels on susceptible hosts and damage to potato crops. Currently, regions of the United Kingdom with warm soil temperatures are also expected to have high levels of hatching of PCN, and therefore greater multiplication resulting in greater challenges in the management of these nematodes in infested land.

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

    Directory of Open Access Journals (Sweden)

    Roniram Pereira da Silva

    2014-04-01

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

  14. Influence of humified organic matter on copper behavior in acid polluted soils

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Calvino, D., E-mail: davidfc@uvigo.e [Plant Biology and Soil Science Department, University of Vigo, Ourense Campus, 32004 Ourense (Spain); Soler-Rovira, P.; Polo, A. [Centro de Ciencias Medioambientales, Consejo Superior de Investigaciones Cientificas, Serrano 115 dpdo., 28006 Madrid (Spain); Arias-Estevez, M. [Plant Biology and Soil Science Department, University of Vigo, Ourense Campus, 32004 Ourense (Spain); Plaza, C. [Centro de Ciencias Medioambientales, Consejo Superior de Investigaciones Cientificas, Serrano 115 dpdo., 28006 Madrid (Spain)

    2010-12-15

    The main purpose of this work was to identify the role of soil humic acids (HAs) in controlling the behavior of Cu(II) in vineyard soils by exploring the relationship between the chemical and binding properties of HA fractions and those of soil as a whole. The study was conducted on soils with a sandy loam texture, pH 4.3-5.0, a carbon content of 12.4-41.0 g kg{sup -1} and Cu concentrations from 11 to 666 mg kg{sup -1}. The metal complexing capacity of HA extracts obtained from the soils ranged from 0.69 to 1.02 mol kg{sup -1}, and the stability constants for the metal ion-HA complexes formed, log K, from 5.07 to 5.36. Organic matter-quality related characteristics had little influence on Cu adsorption in acid soils, especially if compared with pH, the degree of Cu saturation and the amount of soil organic matter. - The effect of organic matter quality on Cu adsorption in acid soils was low compared with other soil characteristics such as pH or degree of Cu saturation.

  15. Soil physical properties and grape yield influenced by cover crops and management systems

    Directory of Open Access Journals (Sweden)

    Jaqueline Dalla Rosa

    2013-10-01

    Full Text Available The use of cover crops in vineyards is a conservation practice with the purpose of reducing soil erosion and improving the soil physical quality. The objective of this study was to evaluate cover crop species and management systems on soil physical properties and grape yield. The experiment was carried out in Bento Gonçalves, RS, Southern Brazil, on a Haplic Cambisol, in a vineyard established in 1989, using White and Rose Niagara grape (Vitis labrusca L. in a horizontal, overhead trellis system. The treatments were established in 2002, consisting of three cover crops: spontaneous species (SS, black oat (Avena strigosa Schreb (BO, and a mixture of white clover (Trifolium repens L., red clover (Trifolium pratense L. and annual rye-grass (Lolium multiflorum L. (MC. Two management systems were applied: desiccation with herbicide (D and mechanical mowing (M. Soil under a native forest (NF area was collected as a reference. The experimental design consisted of completely randomized blocks, with three replications. The soil physical properties in the vine rows were not influenced by cover crops and were similar to the native forest, with good quality of the soil structure. In the inter-rows, however, there was a reduction in biopores, macroporosity, total porosity and an increase in soil density, related to the compaction of the surface soil layer. The M system increased soil aggregate stability compared to the D system. The treatments affected grapevine yield only in years with excess or irregular rainfall.

  16. Influence of soil properties on the bioaccumulation and effects of arsenic in the earthworm Eisenia andrei.

    Science.gov (United States)

    Romero-Freire, A; Peinado, F J Martín; Ortiz, M Díez; van Gestel, C A M

    2015-10-01

    This study aimed at assessing the influence of soil properties on the uptake and toxicity effects of arsenic in the earthworm Eisenia andrei exposed for 4 weeks to seven natural soils spiked with different arsenic concentrations. Water-soluble soil concentrations (AsW) and internal As concentrations in the earthworms (AsE) were greatly different between soils. These two variables were highly correlated and were key factors in earthworm toxicity response. AsW was explained by some soil properties, such as the pH, calcium carbonate content, ionic strength, texture or oxide forms. Toxicity showed a clear variation between soils, in some cases without achieving 50 % adverse effect at the highest As concentration added (600 mg kg(-1)). Nevertheless, soil properties did not show, in general, a high relation with studied toxicity endpoints, although the high correlation with AsW could greatly reduce indirectly As bioavailability and toxicity risk for earthworms. Obtained results suggest that soil properties should be part of the criteria to establishing thresholds for contaminated soils because they will be key in controlling As availability and thus result in different degrees of toxicity.

  17. The Influence of Extreme Water Pulses on Greenhouse Gas Emissions from Soils

    Science.gov (United States)

    Petrakis, S.; Vargas, R.; Seyfferth, A.; Kan, J.; Inamdar, S. P.

    2015-12-01

    Anthropogenic activity increasing the amount of radiatively active gases, or Greenhouse Gases (GHGs) in the earth's atmosphere has led to shifts in weather patterns. Climate models predict the occurrence of large storms may increase in frequency and intensity in the mid-Atlantic region. Knowing that extreme precipitation events are rare, testing the influence of large water pulses across different soil types within an ecosystem is challenging. Large additions of water could promote or inhibit microbial activity, and change soil chemistry within a few days. Rapid changes in soil moisture lead to shifts in the behavior of soils as either sinks or sources of several GHGs (i.e., CO2, CH4 and N2O). Unfortunately, it is still unclear how rewetting events could impact the magnitude of GHG fluxes and how changing soil chemical parameters influence these responses. An experiment was designed to test the influence of extreme repeated water pulses on GHG fluxes from four different soils, representing key topographic locations within a watershed in the Piedmont region (i.e., forested upland, forested lowland, creek, wetland). Intact soil cores from these four soil types were kept under constant temperature (22oC) and we measured their responses to extreme water pulses. We continuously (hourly resolution) measured CO2, CH4 and N2O fluxes using a LI-8100A (Licor, Lincoln, NE) multiplexed system coupled to a Picarro G2508 (Picarro, Santa Clara, CA). Furthermore, we used a rhizolysimeter for porewater extraction to measure pH, redox, and water chemistry throughout the experiment. We hypothesized that repeated extreme water pulses would result in non-linear responses of GHG flux magnitudes and dynamics, and these dynamics would relate to changes in soil chemistry. We found that soil moisture alone could not explain the dynamics of GHG fluxes, but these extreme water pulses influenced the overall temporal patterns of all GHGs across all soil types. We also examined the 100 year

  18. Transcending Landscapes: Working Across Scales and Levels in Pastoralist Rangeland Governance.

    Science.gov (United States)

    Robinson, Lance W; Ontiri, Enoch; Alemu, Tsegaye; Moiko, Stephen S

    2017-08-01

    Landscape approaches can be subjected to mistakenly targeting a single "best" level of governance, and paying too little attention to the role that cross-scale and cross-level interactions play in governance. In rangeland settings, resources, patterns of use of those resources, and the institutions for managing the resources exist at multiple levels and scales. While the scholarship on commons offers some guidance on how to conceptualize governance in rangeland landscapes, some elements of commons scholarship-notably the "design principles" for effective governance of commons-do not seem to apply neatly to governance in pastoralist rangeland settings. This paper examines three cases where attempts have been made to foster effective landscape governance in such settings to consider how the materiality of commons influences the nature of cross-scale and cross-level interactions, and how these interactions affect governance. In all three cases, although external actors seemed to work appropriately and effectively at community and landscape levels, landscape governance mechanisms have been facing great challenges arising from relationships beyond the landscape, both vertically to higher levels of decision-making and horizontally to communities normally residing in other landscapes. The cases demonstrate that fostering effective landscape-level governance cannot be accomplished only through action at the landscape level; it is a task that must be pursued at multiple levels and in relation to the connections across scales and levels. The paper suggests elements of a conceptual framework for understanding cross-level and cross-scale elements of landscape governance, and offers suggestions for governance design in pastoralist rangeland settings.

  19. Transcending Landscapes: Working Across Scales and Levels in Pastoralist Rangeland Governance

    Science.gov (United States)

    Robinson, Lance W.; Ontiri, Enoch; Alemu, Tsegaye; Moiko, Stephen S.

    2017-08-01

    Landscape approaches can be subjected to mistakenly targeting a single "best" level of governance, and paying too little attention to the role that cross-scale and cross-level interactions play in governance. In rangeland settings, resources, patterns of use of those resources, and the institutions for managing the resources exist at multiple levels and scales. While the scholarship on commons offers some guidance on how to conceptualize governance in rangeland landscapes, some elements of commons scholarship—notably the "design principles" for effective governance of commons—do not seem to apply neatly to governance in pastoralist rangeland settings. This paper examines three cases where attempts have been made to foster effective landscape governance in such settings to consider how the materiality of commons influences the nature of cross-scale and cross-level interactions, and how these interactions affect governance. In all three cases, although external actors seemed to work appropriately and effectively at community and landscape levels, landscape governance mechanisms have been facing great challenges arising from relationships beyond the landscape, both vertically to higher levels of decision-making and horizontally to communities normally residing in other landscapes. The cases demonstrate that fostering effective landscape-level governance cannot be accomplished only through action at the landscape level; it is a task that must be pursued at multiple levels and in relation to the connections across scales and levels. The paper suggests elements of a conceptual framework for understanding cross-level and cross-scale elements of landscape governance, and offers suggestions for governance design in pastoralist rangeland settings.

  20. Regional estimation of soil C stocks and CO2 emissions as influenced by cropping systems and soil type

    Science.gov (United States)

    Farina, Roberta; Marchetti, Alessandro; Di Bene, Claudia

    2015-04-01

    Soil organic matter (SOM) is of crucial importance for agricultural soil quality and fertility. At global level soil contains about three times the carbon stored in the vegetation and about twice that present in the atmosphere. Soil could act as source and sink of carbon, influencing the balance of CO2 concentration and consequently the global climate. The sink/source ratio depends on many factors that encompass climate, soil characteristics and different land management practices. Thus, the relatively large gross exchange of GHGs between atmosphere and soils and the significant stocks of carbon in soils, may have significant impact on climate and on soil quality. To quantify the dynamics of C induced by land cover change and the spatial and temporal dynamics of C sources and sinks at regional and, potentially, at national and global scales, we propose a methodology, based on a bio-physical model combined with a spatial explicit database to estimate C stock changes and emissions/removals. The study has been conducted in a pilot region in Italy (Apulia, Foggia province), considering the typical cropping systems of the area, namely rainfed cereals, tomato, vineyard and olives. For this purpose, the model RothC10N (Farina et al., 2013), that simulates soil C dynamics, has been modified to work directly in batch using data of climate, soil (over 290 georeferenced soil profiles), annual agriculture land use (1200 observations) The C inputs from crops have been estimated using statistics and data from literature. The model was run to equilibrium for each point of soil, in order to make all the data homogeneous in terms of time. The obtained data were interpolate with geostatisical procedures, obtaining a set of 30x30 km grid with the initial soil C. The new layer produced, together with soil and land use layers, were used for a long-term run (12 years). Results showed that olive groves and vineyards were able to stock a considerable amount of C (from 0.4 to 1.5 t ha-1 y

  1. Assessment of LANDSAT for rangeland mapping, Rush Valley, Utah

    Science.gov (United States)

    Ridd, M. K.; Price, K. P.; Douglass, G. E.

    1984-01-01

    The feasibility of using LANDSAT MSS (multispectral scanner) data to identify and map cover types for rangeland, and to determine comparative condition of the ecotypes was assessed. A supporting objective is to assess the utility of various forms of aerial photography in the process. If rangelands can be efficiently mapped with Landsat data, as supported by appropriate aerial photography and field data, then uniform standards of cover classification and condition may be applied across the rangelands of the state. Further, a foundation may be established for long-term monitoring of range trend, using the same satellite system over time.

  2. Soil microbial communities alter leaf chemistry and influence allelopathic potential among coexisting plant species.

    Science.gov (United States)

    Meiners, Scott J; Phipps, Kelsey K; Pendergast, Thomas H; Canam, Thomas; Carson, Walter P

    2017-04-01

    While both plant-soil feedbacks and allelochemical interactions are key drivers of plant community dynamics, the potential for these two drivers to interact with each other remains largely unexplored. If soil microbes influence allelochemical production, this would represent a novel dimension of heterogeneity in plant-soil feedbacks. To explore the linkage between soil microbial communities and plant chemistry, we experimentally generated soil microbial communities and evaluated their impact on leaf chemical composition and allelopathic potential. Four native perennial old-field species (two each of Aster and Solidago) were grown in pairwise combination with each species' soil microbial community as well as a sterilized inoculum. We demonstrated unequivocally that variation in soil microbial communities altered leaf chemical fingerprints for all focal plant species and also changed their allelopathic potential. Soil microbes reduced allelopathic potential in bioassays by increasing germination 25-54% relative to sterile control soils in all four species. Plants grown with their own microbial communities had the lowest allelopathic potential, suggesting that allelochemical production may be lessened when growing with microbes from conspecifics. The allelopathic potential of plants grown in congener and confamilial soils was indistinguishable from each other, indicating an equivalent response to all non-conspecific microbial communities within these closely related genera. Our results clearly demonstrated that soil microbial communities cause changes in leaf tissue chemistry that altered their allelopathic properties. These findings represent a new mechanism of plant-soil feedbacks that may structure perennial plant communities over very small spatial scales that must be explored in much more detail.

  3. Sorption and desorption kinetics of cadmium from soils: Influence of phosphate

    Energy Technology Data Exchange (ETDEWEB)

    Krishnamurti, G.S.R.; Huang, P.M.; Kozak, L.M.

    1999-12-01

    The mobility and availability of heavy metals is controlled by sorption-desorption characteristics of the soils. There is much literature available about the sorption characteristics of heavy metals by soils. However, the influence of ionic environments on the desorption kinetics of heavy metals, particularly Cd, have not been studied in detail. The present study reports the kinetic data of desorption of Cd from two soils, with contrasting Cd availability characteristics, using 1 M NH{sub 4}Cl. The soils were preadsorbed with different amounts of Cd in the presence of monoammonium phosphate. The Cd was sorbed onto the soils almost instantaneously in the absence of phosphate, with >97% of the Cd added to the soils sorbed within the first 15 min of reaction time. The Freundilich parameter a, the sorption coefficient, which is related to the Cd sorption capacity, indicated that the phosphate retarded Cd sorption by both soils by at least one order of magnitude. The overall diffusion coefficient of Cd release from the Luseland soil by 1 M NH{sub 4}Cl, obtained using the parabolic diffusion model for the desorption kinetics, was 1.62 to 10.1 times higher than that of the Judburgh soil, depending on the initial amount of Cd preadsorbed. The lower the amount of initial Cd preadsorbed, the greater the difference in the rate of Cd released between the two soils. The presence of phosphate during Cd adsorption by the soils increased the amount of Cd released in the initial 30-min reaction period as well as the overall diffusion coefficients of Cd release. The kinetic data of Cd desorption reflect well the Cd availability index and grain Cd content of the durum wheat crops, Kyle and Arcola, grown in the two soils.

  4. Influence of Different Slope Aspects on Some Soil Properties and Forest Soils Evolution (Case Study: Rostam Abad Region, Guilan Province

    Directory of Open Access Journals (Sweden)

    M. Zarinibahador

    2016-02-01

    Full Text Available Introduction: Spatial variation of soil properties is significantly influenced by numerous environmental factors such as landscape features, including position, topography, slope gradient and aspect, parent material, climate and vegetation. Soil properties vary spatially in south- and north-facing hill slopes. This factor (different slope aspects can affect the distribution of soil organic matter, the presence or absence of a layer, pH, nutrient levels, soil mineralogical and micromorphological properties. Topographic factors such as the orientation of the hill slope and the steepness of the slope affect microclimate, vegetation establishment, water movement and erosion. Aspect and slope control the movement of water and materials in a hill slope and contribute to differences in soil properties. Temperature, precipitation and climate vary with elevation and influence pedogenic processes. Accelerated rates of weathering and soil development were found to occur in soils on south-facing slopes. Slopes with a south aspect are dominated by stone and bare soil patches, while slopes with a north aspect are dominated by biotic components. Northern slopes have higher productivity and species diversity compared to Southern slopes. Slope aspect has a significant effect on the composition, species richness, structure and density of plant communities, differed significantly between North- and South- facing slopes. Materials and Methods: In the present study, the effects of two slope aspects on some soil properties and soil evolution was investigated in Northern Rostam Abad region in the Guilan Province. Five profiles in Southern hill slope(South-facing hill slopes and five profiles in Northern hill slopes(North-facing hill slopes with 40% slope and same parent material (basaltic andesite and same plant cover were dug. The elevation of two slope aspects was 240 meters from the sea level. Average annual temperatures and precipitation are16 degrees centigrade

  5. The Influence of Nitrogen on the Biological Properties of Soil Contaminated with Zinc.

    Science.gov (United States)

    Strachel, Rafał; Wyszkowska, Jadwiga; Baćmaga, Małgorzata

    2017-03-01

    This study analyzed the relationship between nitrogen fertilization and the biological properties of soil contaminated with zinc. The influence of various concentrations of zinc and nitrogen on the microbiological and biochemical activity of soil was investigated. In a laboratory experiment, loamy sand with pHKCl 5.6 was contaminated with zinc (ZnCl2) and fertilized with urea as a source of nitrogen. The activity of acid phosphatase, alkaline phosphatase, urease and β-glucosidase, and microbial counts were determined in soil samples after 2 and 20 weeks of incubation. Zinc generally stimulated hydrolase activity, but the highest zinc dose (1250 mg kg-1) led to the inhibition of hydrolases. Nitrogen was not highly effective in neutralizing zinc's negative effect on enzyme activity, but it stimulated the growth of soil-dwelling microorganisms. The changes in soil acidity observed after the addition of urea modified the structure of microbial communities.

  6. Variation in winter snowpack depth and duration influences summer soil respiration in a subalpine meadow

    Science.gov (United States)

    Arnold, C. L.; Ghezzehei, T. A.; Berhe, A. A.

    2012-12-01

    Subalpine meadows in the Sierra Nevada rely on the depth and duration of the winter snowpack to supply ample water to restore the water table in the meadow during the spring snowmelt. This study examines the role that interannual variability in the winter snowpack plays in the overall rate of summer soil respiration along a hydrologic gradient in a subalpine meadow. Carbon dioxide efflux from the meadow was measured from June through September in 2011 and 2012 using soil collars and a LICOR 8100A infrared gas analyzer. Preliminary results show that soil respiration rates are influenced by the hydrologic gradient across the meadow, with drier regions peaking earlier in the summer as compared to wetter regions. We also show that high snowpack years can suppress soil respiration in the meadow until late in the summer season as compared to low snowpack years, where soil respiration peaks early in the summer.

  7. Influence of relief and vegetation on soil properties in a disturbed chernozem soil landscape

    Science.gov (United States)

    Raab, Thomas; Hirsch, Florian; Vasserman, Oleksandr; Raab, Alexandra; Naeth, Anne

    2017-04-01

    In central and southeastern Alberta, chernozems dominate the soil landscape and are divided into several groups that follow the climate gradient from Northwest to Southeast: Dark Grey Chernozems, Black Chernozems, Dark Brown Chernozems; Brown Chernozems. Principles controlling development and distribution of these chernozem subtypes along the ecotone transect are quite well known. However, intensive land use over the last century has affected soils that originally have formed under natural conditions during the Holocene in more than 10,000 years. There is a lack of knowledge regarding soil development in these landscapes on the decadal to centennial time scale. Within this time frame the most important factor of soil formation may be relief, although this has not been properly studied. This study aims to compare soil properties in a typical chernozem landscape where soils have been highly disturbed and parent materials have been re-arranged by surface coal mining. We hypothesize that within 50 years, soils develop with significant differences based on vegetation type and slope aspect. Our study site is the former Diplomat Mine near Forestburg, Alberta where spoils form a small scale ridge and graben topography. The south facing slopes of the piles are covered by grassland, whereas on the north exposition has trees and shrubs. Samples were taken from six sites with differences in topography and vegetation type. Diplomate T1 is at the top of the ridge with grassland, Diplomate S1 is on the southern slope with grassland, Diplomate N1 is on the northern slope with trees, and Diplomate N2 is on the northern slope with shrubs. For comparison we took samples from two sites without slope aspect. One site was an undisturbed grassland (Diplomate Z1) and the other sites were reclaimed piles (Diplomate R1). At each site, five soil profiles were examined and volumetrically sampled (250 cm3 steel ring) in steps of five centimeters to a depth of 30 centimeters. We present first

  8. Variation of terpenes in milk and cultured cream from Norwegian alpine rangeland-fed and in-door fed cows.

    Science.gov (United States)

    Borge, Grethe Iren A; Sandberg, Ellen; Øyaas, Jorun; Abrahamsen, Roger K

    2016-05-15

    The terpene content of milk and cream made from milk obtained from cows fed indoors, and by early or late grazing, in alpine rangeland farms in Norway, were analysed for three consecutive years. The main terpenes identified and semi-quantified were the monoterpenes β-pinene, α-pinene, α-thujene, camphene, sabinene, δ-3-carene, d-limonene, γ-terpinene, camphor, β-citronellene, and the sesquiterpene β-caryophyllene. The average total terpene content increased five times during the alpine rangeland feeding period. The terpenes α-thujene, sabinene, γ-terpinene and β-citronellene were only detected in milk and cultured cream from the alpine rangeland feeding period and not in samples from the indoors feeding period. These four terpenes could be used, as indicators, to show that milk and cultured cream originate from the alpine rangeland feeding period. The terpenes did not influence the sensorial quality of the milk or the cultured cream. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Biogeochemical features technogenic pollution of soils under the influence chemical industry

    Directory of Open Access Journals (Sweden)

    Kuraeva I.V.

    2015-09-01

    Full Text Available The physico-chemical properties of soil (pH, organic matter content, cation exchange capacity. The regularities of the distribution of total and mobile forms of heavy metals in soil sediments in the territory of Shostka Sumy region under the influence of the chemical industry and in the background areas. Biogeochemical indicators obtained content of microscopic fungi and their species, the most characteristic of the study of soils, which can be used as an additional criterion for ecological and geochemical studies.

  10. [Influence of continuous cropping on growth of Artemisia annua and bacterial communities in soil].

    Science.gov (United States)

    Li, Qian; Yuan, Ling; Yang, Shui-Ping; Cheng, Yu-Yuan; Cui, Guang-Lin; Huang, Jian-Guo

    2016-05-01

    In this study, several types of Artemisia annua in soil, including the soil which had not been planted, or planted for one year, or continuously planted for three or five years were collected, in order to study the influences of continuous cropping on the growth of A. annua, content of artemisinin, available nutrient of soil, and bacterial community structure through adopting routine analysis and Illumina MiSeq high-throughput sequencing. The results showed that continuous cropping inhibited significantly the growth of A. annua and reduced leaf biomass, content and yield of artemisinin, with the maximum decreasing amplitude of 30.20%, 7.70% and 35.58% respectively. The content of soil organic matter, available nitrogen, available phosphorus and 16S rRNA sequence number were increased to different extents after continuous cropping of A. annua. According to the results of high-throughput sequencing, 634-812 types of common bacteria belonged to 21 categories were planted in different soil of A. annua with different planting years, which represented that the distribution distance of the point of bacterial community with different years among coordinate system of principal component was relative distant, and community structure had significant changes (Preproduction of soil bacteria, and influenced the supply and transform of soil nutrient, leading to a poor growth and resulting in reduction of artemisinin content and yield. Therefore, it is necessary to advocate crop rotation in the process of planting A. annua. Copyright© by the Chinese Pharmaceutical Association.

  11. The influence of natural factors on the concentrations of chemical elements in urban soils

    Science.gov (United States)

    Alekseenko, Alexey; Alekseenko, Vladimir

    2013-04-01

    The statistically treated results of more than 10 000 soil samples analyses for 25 elements were used during the work preparing. For estimating the total influence of natural factors on the global level we could consider the average concentrations in urban soils (the Clarke numbers of urban soils) with the average concentrations in the Earth crust and Earth soils. The analysis showed the heredity of general properties of elements concentrations from the Earth crust. However the higher concentrations of As, Cd, Cs, Mo, N, S, Ti and V in the soils of cities are explained by the combined effects of processes of soil formation and human impact, and Zn, Pb, Ba, Sr, Ca, Hg, B - by the prevailing human impact. On the regional level the natural factors influence was estimated by the comparing of soils of cities with the equal technogenic impact and number of population, but located in different geographical and climate zones. The common conformities with law were not found out, but the mentioned factors had an effect on the elements concentrations. The valuation of natural factors influence in the soils of one city was carried out by comparison the urban landscapes soils, which differ only in one characteristic. Geomorphologic peculiarities had the doubtless influence on the background concentrations of Pb, Sr, Ag, Zn, Yb, Co, Sn, Cr. etc., but in every case the connection of maximum and minimum background concentrations of the specific elements with the certain geomorphologic structures depended on number of building storeys, location of industrial zones, parks, etc. The certain associations of plants were also affected the background elements concentrations in soils of several cities. The increased concentrations of elements were more often detected - other things being equal - in the landscapes with mixed decorative fruit and berry plant association (?u, Pb, Co, Mn, Ti, Sr), less often - with agricultural fruit and berry plant association (Zn, Ag, Sn, Ba, Cr). In parks

  12. Influence of soil chemical properties on relative abundance of arbuscular mycorrhiza in forested soils in Malaysia

    OpenAIRE

    ONG, Kian Huat; CHUBO, John Keen; KING, Jie Hung; LEE, Chia Shing; SU, Dennis Shan An; SIPEN, Philip

    2012-01-01

    The effect of soil chemical properties on the diversity and colonization of arbuscular mycorrhiza (AM) varies among ecosystems. This study was conducted to assess and compare the abundance of AM in a rehabilitated forest and a logged-over forest soil using the most probable number and spore number methods. Glomus (71.7%-82.1%) and Acaulospora (17.4%-19.5%) were found to be abundant in both sites, while Gigaspora was found only in the logged-over forest. The abundance of AM in the rehabilitate...

  13. Soil organic matter of a sandy soil influenced by agronomy and climate

    OpenAIRE

    ELLMER, Frank

    2008-01-01

    Long term field experiments are being conducted at Humboldt University of Berlin (Germany) to obtain information regarding sustainable management of arable land with sandy soils. In Thyrow, a location in the south of Berlin with silty and sandy soil (85 % sand, 12 % silt, 3 % clay, 0.5 % Corg, pH 5.5) several experiments have been carried out since 1937. They include the study of the long-term effects of the agronomic factors of: crop rotation; organic fertilization; mineral ferti...

  14. Management of communal rangelands - the dialogue between science and indigenous knowledge: the case of the Eastern Cape

    CSIR Research Space (South Africa)

    Dube, S

    2010-07-01

    Full Text Available Communal area rangeland resource users are an important part of the rangeland ecosystem; rangeland management policies and practice should, therefore, accommodate their socio-cultural practices and knowledge. Indigenous knowledge (IK) is often...

  15. The influence of soil type, soil water and share sharpness of a mouldboard plough on energy consumption, rate of work and tillage quality

    Energy Technology Data Exchange (ETDEWEB)

    Natsis, A. [Station of Agricultural Power and Machinery of Sarante, Finiq (Albania); Agricultural University of Athens (Greece); Papadakis, G.; Pitsilis, J. [Agricultural University of Athens (Greece)

    1999-07-01

    The results of field tests to investigate the influence of soil type and soil water on the wear of soil tillage tools are presented. The soil water had a positive effect for loam and clay soils because the wear decreased as the water content increased. For sandy soils however, wear increased with soil water. As the thickness of the cutting edge of the plough increased, draught force and fuel consumption increased considerably, while rate of work and tillage depth increased. The quality of the tillage was seriously reduced, that is, the size of the soil clods increased as the thickness of the cutting edge of the plough increased. Also, the percentage of surface residues was greater as the thickness of the cutting edge of the plough increased. The best overall performance of the plough was obtained from the sharpest share cutting edge with a thickness of 1 mm. (author)

  16. The predictable influence of soil temperature and barometric pressure changes on vapor intrusion

    Science.gov (United States)

    Barnes, David L.; McRae, Mary F.

    2017-02-01

    Intrusion of volatile organic compounds in the gas phase has impacted many buildings in many different locations. Various building and environmental factors such as buoyancy of heated air and changes in barometric pressure can influence indoor air concentrations due to vapor intrusion in these buildings resulting in seasonal and daily variability. One environmental factor that previous research has not adequately addressed is soil temperature. In this study we present two northern region study sites where the seasonal trends in indoor air VOC concentrations positively correlate with soil temperature, and short-term (days) variations are associated with barometric pressure changes. We present simple and multivariate linear relationships of indoor air concentrations as a function of soil temperature and barometric pressure. Results from this study show that small changes in soil temperature can result in relatively large changes in indoor air VOC concentrations where the gas phase VOCs are sourced from non-aqueous phase liquids contained in the soil. We use the results from this study to show that a five degree Celsius increase in soil temperature, a variation in soil temperature that is possible in many climatic regions, results in a two-fold increase in indoor air VOC concentrations. Additionally, analysis provides insight into how building ventilation, diffusion, and the relative rate of soil-gas flow across the slab both from the subsurface into the building and from the building into the subsurface impact short term variations in concentrations. With these results we are able to provide monitoring recommendations for practitioners.

  17. THE INFLUENCES OF GEOMORPHOLOGICAL FACTORS ON SOIL CHARACTERISTICS IN AYVALIDERE BASIN (SULEYMANPASA/TEKIRDAG

    Directory of Open Access Journals (Sweden)

    Emre ÖZŞAHİN

    2016-01-01

    Full Text Available In this paper, the influences of geomorphological factors on the soil characteristics is studied on the basis of Ayvalıdere Basin. The fact that these relationships are examined within a sample basin constitutes the significance of the study. In this study, KIRKLARELI F19-d4 and BANDIRMA G19-a1 topographic maps on a scale of 1:25.000 are used. As to methodology, firstly the geomorphological characteristics of the basin area were identified. Afterwards, the detailed soil map of the area was formed by making use of the sample soil analyses by other researchers and the other study findings. Whether or not geomorpho- logical characteristics affect soil distribution in the basin was scrutinized by comparing and contrasting both geomorphological characteristics (landforms, slope, aspect, altitude and soil characteristics on GIS (Geographic Information Systems. It was found and emphasized as a result that the relationship between landforms and the soil characteristics significantly differs even in short distances. There is a need for more detailed research on this relationship. Thus, the obtained results may be used to take concrete steps for the conservation of soil resource and their proper use and planning. Finally, similar research on the rela- tionship between soil and the landforms dealing with pedological and geomorphological characteristics may help us to understand and analyze the natural environment better.

  18. Influence of Soil Organic Matter Content on Abundance and Biomass of Earthworm (Oligochaeta: Lumbricidae Populations

    Directory of Open Access Journals (Sweden)

    Hristo Valchovski

    2016-06-01

    Full Text Available The current study explores the influence of soil organic matter content on abundance and biomass of earthworm communities. The observation was carried out on three type of soils: PellicVertisols (very fine texture, Cromi-Vertic Luvisols (fine texture and Calcaric Fluvisols (mediumtexture from the Balkan Peninsula (Bulgaria. The field experiment was provided on uncultivatedplots. In the studied area earthworm fauna comprises of four species: Aporrectodea rosea,Aporrectodea caliginosa, Lumbricus terrestris and Octolasion lacteum. We found peregrine lumbricidtaxa, which are widely distributed in European soils. Our study demonstrated that soil organicmatter has a positive effect on lumbricid populations. It was revealed that augmentation of soilorganic matter favours characteristics of earthworm communities. The soil organic matter contentand earthworm abundance are in strong positive correlation (r > 0.981. The same relationship wasrevealed between the biomass of lumbricid fauna and amount of soil organic matter (r > 0.987. Insum, the soil organic matter could be used as an indicator for earthworm communities inuncultivated soils.

  19. [Influence of diesel fuel on the number of selected soil microorganisms group].

    Science.gov (United States)

    Hawrot-Paw, Małgorzata

    2012-01-01

    Among a range of xenobiotics, that are introduced into the environment, especially dangerous are petroleum substances. Microorganisms participating in their decomposition, may be a good effectiveness indicator of biodegradation process. The aim of this study was to determine the influence of soil contamination with diesel oil for changes in number of basic taxonomic groups of microorganisms, including bacteria, actinomycetes and fungi. The study was carried out in two soils, loamy sand and sandy clay, which, apart from granulometric composition also differed in organic matter content. Two levels of diesel contamination was used: 5% and 15% w/w of soil d.m. The soil samples, not contaminated with diesel oil, was left as a experience control objects. The number of microorganisms were evaluated by automated method with measuring impedance in media, using the analyzer BacTrac 4100. In the studied soils the largest group of microorganisms were bacteria, significantly less was fungi and actinomycetes. Based on the results of research it was found a significant effect on the quantitative composition of microflora was both contamination dose and type of soil. Diesel fuel at a concentration of 5% stimulated the number of bacteria and fungi in sandy soil. In general, increase in concentration of pollutants adversely affect the microorganisms, especially in loamy soils. Soil contamination with diesel oil resulted in a reduction in the degree of microbial growth rate (55% in loamy sand and 39% in sandy clay), and thus have an impact on their fertility. The reduction of SR index was correlated with increasing dose of pollutants. Diesel oil affect the biological balance of soil and stimulates or reduces the number of different groups of microorganisms, depending on the amount of fuel. The presence of fuel decrease index of soil fertility, proportion to increase in the level of contamination.

  20. How soil type (gypsum or limestone) influences the properties and composition of thyme honey.

    Science.gov (United States)

    González-Porto, Amelia Virginia; Martín Arroyo, Tomás; Bartolomé Esteban, Carmen

    2016-01-01

    The objective of this work was to determine the influence of the soil substrate on the characteristics and properties of a specific type of honey. As such, we analysed the features of a typical single-flower honey, thyme honey, produced in a specific Mediterranean region. Thymus is a genus of aromatic perennial plants that are native to Europe, North Africa and Asia. A total of 70 honey samples from hives situated on limestone (38 samples) or gypsum soils (32 samples) were studied. The physical and chemical properties of each samples were analyzed using standard assays. Within the same geographical area and despite a similar thyme pollen content, we observed variation in the physicochemical, antioxidant and sensorial characteristics of monofloral honeys. The quantification of certain physicochemical parameters of the honey indicated these features were influenced by the soil type. Indeed, the soil type of the hives' settlement area, limestone or gypsum, influences the conductivity, antioxidant capacity, colour and floristic composition. The present work demonstrates that soil type (gypsum or limestone) influences the characteristics of honey, potentially providing added market value to these products.

  1. Sahelian rangeland response to changes in rainfall over two decades in the Gourma region, Mali

    Science.gov (United States)

    Hiernaux, Pierre; Mougin, Eric; Diarra, Lassine; Soumaguel, Nogmana; Lavenu, François; Tracol, Yann; Diawara, Mamadou

    2009-08-01

    SummaryTwenty-five rangeland sites were monitored over two decades (1984-2006) first to assess the impact of the 1983-1984 droughts on fodder resources, then to better understand ecosystem functioning and dynamics. Sites are sampled along the south-north bioclimatic gradient in Gourma (Mali), within three main edaphic situations: sandy, loamy-clay and shallow soils. In addition, three levels of grazing pressure where systematically sampled within sandy soils. Located at the northern edge of the area reached by the West African monsoon, the Gourma gradient has recorded extremes in inter-annual variations of rainfall and resulting variations in vegetation growth. Following rainfall variability, inter-annual variability of herbaceous yield increases as climate gets dryer with latitudes at least on the sandy soils sites. Local redistribution of rainfall explains the high patchiness of herbaceous vegetation, especially on shallow soils. Yet spatial heterogeneity of the vegetation does not buffer between year yield variability that increases with spatial heterogeneity. At short term, livestock grazing during the wet season affects plant growth and thus yield in direction and proportions that vary with the timing and intensity of grazing. In the longer term, grazing also impinges upon species composition in many ways. Hence, long histories of heavy grazing promote either long cycle annuals refused by livestock or else short cycle good quality feed species. Primary production is maintained or even increased in the case of refusal such as Sida cordifolia, and is lessened in the case of short cycle species such as Zornia glochidiata. These behaviours explain that the yield anomalies calculated for the rangelands on sandy soils relative to the yield of site less grazed under similar climate tend to be negative in northern Sahel where the scenario of short cycle species dominates, while yield anomalies are close to nil in centre Sahel and slightly positive in South Sahel where

  2. Rehabilitation of Great Basin rangelands: an integrated approach

    Science.gov (United States)

    Disturbed rangelands present significant challenges to resource managers and land owners. In the Great Basin, exotic annual grasses have truncated secondary succession by outcompeting native perennial species for limited moisture and nutrients. An integrated approach to successfully control such inv...

  3. Future scenarios of impacts to ecosystem services on California rangelands

    Science.gov (United States)

    Byrd, Kristin; Alvarez, Pelayo; Flint, Lorraine; Flint, Alan

    2014-01-01

    The 18 million acres of rangelands in the Central Valley of California provide multiple benefits or “ecosystem services” to people—including wildlife habitat, water supply, open space, recreation, and cultural resources. Most of this land is privately owned and managed for livestock production. These rangelands are vulnerable to land-use conversion and climate change. To help resource managers assess the impacts of land-use change and climate change, U.S. Geological Survey scientists and their cooperators developed scenarios to quantify and map changes to three main rangeland ecosystem services—wildlife habitat, water supply, and carbon sequestration. Project results will help prioritize strategies to conserve these rangelands and the ecosystem services that they provide.

  4. Copper dynamics under alternating redox conditions is influenced by soil properties and contamination source.

    Science.gov (United States)

    Balint, Ramona; Said-Pullicino, Daniel; Ajmone-Marsan, Franco

    2015-02-01

    Understanding the effect of soil redox conditions on contaminant dynamics is of significant importance for evaluating their lability, mobility and potential transfer to other environmental compartments. Under changing redox conditions, soil properties and constituents such as Fe and Mn (hydr)oxides and organic matter (OM) may influence the behavior of associated metallic elements (MEs). In this work, the redox-driven release and redistribution of Cu between different soil pools was studied in three soils having different contamination sources. This was achieved by subjecting soil columns to a series of alternating reducing and oxidizing cycles under non-limiting C conditions, and assessing their influence on soil pore water, leachate and solid phase composition. Results showed that, in all soils, alternating redox conditions led to an increase in the distribution of Cu in the more labile fractions, consequently enhancing its susceptibility to loss. This was generally linked to the redox-driven cycling of Fe, Mn and dissolved organic matter (DOM). In fact, results suggested that the reductive dissolution of Fe and Mn (hydr)oxides and subsequent reprecipitation as poorly-ordered phases under oxic conditions contributed to the release and mobilization of Cu and/or Cu-containing organometallic complexes. However, the behavior of Cu, as well as the mechanisms controlling Cu release and loss with redox cycling, was influenced by both soil properties (e.g. pH, contents of easily reducible Fe and Mn (hydr)oxides) and source of Cu contamination. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. The influence of use-related, environmental, and managerial factors on soil loss from recreational trails

    Science.gov (United States)

    Olive, Nathaniel D.; Marion, Jeffrey L.

    2009-01-01

    Recreational uses of unsurfaced trails inevitably result in their degradation, with the type and extent of resource impact influenced by factors such as soil texture, topography, climate, trail design and maintenance, and type and amount of use. Of particular concern, the loss of soil through erosion is generally considered a significant and irreversible form of trail impact. This research investigated the influence of several use-related, environmental, and managerial factors on soil loss on recreational trails and roads at Big South Fork National River and Recreation Area, a unit of the U.S. National Park Service. Regression modeling revealed that trail position, trail slope alignment angle, grade, water drainage, and type of use are significant determinants of soil loss. The introduction of individual and groups of variables into a series of regression models provides improved understanding and insights regarding the relative influence of these variables, informing the selection of more effective trail management actions. Study results suggest that trail erosion can be minimized by avoiding “fall-line” alignments, steep grades, and valley-bottom alignments near streams, installing and maintaining adequate densities of tread drainage features, applying gravel to harden treads, and reducing horse and all-terrain vehicle use or restricting them to more resistant routes.This research also sought to develop a more efficient Variable Cross-Sectional Area method for assessing soil loss on trails. This method permitted incorporation of CSA measures in a representative sampling scheme applied to a large (24%) sample of the park's 526 km trail system. The variety of soil loss measures derived from the Variable CSA method, including extrapolated trail-wide soil loss estimates, permit an objective quantification of soil erosion on recreational trails and roads. Such data support relational analyses to increase understanding of trail degradation, and long

  6. Snowcover Influences Upon Episodic Release of Nitrous Oxide from Agricultural Soils During Spring Thaw

    Science.gov (United States)

    Helgason, W.; Farrell, R.; Ens, J.; Lemke, R.; David, C.

    2015-12-01

    In regions where agricultural soils seasonally freeze, such as the Canadian prairies, up to 60-70% of the annual nitrous oxide (N2O) emission can occur during the soil thaw period. The conditions responsible for this episodic release of N2O are poorly understood. In order to elucidate the influencing factors a replicated plot study was conducted in Outlook, Saskatchewan, Canada (51.5°N) during the 2014-2015 winter period. The study compared soil thermal conditions and soil gas fluxes (nitrous oxide and carbon dioxide) from plots that had the snow periodically removed and those on which snow was allowed to accumulate. Soil gas fluxes were measured using an automated chamber system (Gasmet DX4030 FTIR analyzer and Licor Li-8100 chamber system) and analyzer. Soil conditions were continuously monitored throughout the winter and thaw periods. Owing to the insulating effect of snow, the snow free plots were colder during the mid-winter period, but thawed 3-4 days earlier than the snow covered treatment. Following thaw, the snow-free plots were 2-3 degrees warmer than the snow-covered plots for 5-7 days before reaching a similar thermal regime. Due to the differences in the timing of soil thaw and the pre- and post-thaw thermal conditions, cumulative and peak N2O emissions were much higher from the plots that had been kept snow-free. These results suggest that agricultural practices which influence snow redistribution may have an effect upon spring soil gas fluxes. This study also highlights the importance of incorporating snowmelt and soil thaw physics into process-based greenhouse gas models.

  7. Influence of soil type, cultivar and Verticillium dahliae on the structure of the root and rhizosphere soil fungal microbiome of strawberry.

    Science.gov (United States)

    Nallanchakravarthula, Srivathsa; Mahmood, Shahid; Alström, Sadhna; Finlay, Roger D

    2014-01-01

    Sustainable management of crop productivity and health necessitates improved understanding of the ways in which rhizosphere microbial populations interact with each other, with plant roots and their abiotic environment. In this study we examined the effects of different soils and cultivars, and the presence of a soil-borne fungal pathogen, Verticillium dahliae, on the fungal microbiome of the rhizosphere soil and roots of strawberry plants, using high-throughput pyrosequencing. Fungal communities of the roots of two cultivars, Honeoye and Florence, were statistically distinct from those in the rhizosphere soil of the same plants, with little overlap. Roots of plants growing in two contrasting field soils had high relative abundance of Leptodontidium sp. C2 BESC 319 g whereas rhizosphere soil was characterised by high relative abundance of Trichosporon dulcitum or Cryptococcus terreus, depending upon the soil type. Differences between different cultivars were not as clear. Inoculation with the pathogen V. dahliae had a significant influence on community structure, generally decreasing the number of rhizosphere soil- and root-inhabiting fungi. Leptodontidium sp. C2 BESC 319 g was the dominant fungus responding positively to inoculation with V. dahliae. The results suggest that 1) plant roots select microorganisms from the wider rhizosphere pool, 2) that both rhizosphere soil and root inhabiting fungal communities are influenced by V. dahliae and 3) that soil type has a stronger influence on both of these communities than cultivar.

  8. Interspecific competition of early successional plant species in ex-arable fields as influenced by plant–soil feedback

    NARCIS (Netherlands)

    Jing, Y.; Bezemer, T.M.; Putten, van der W.H.

    2015-01-01

    Plant–soil feedback can affect plants that belong to the same (intraspecific feedback) or different species (interspecific feedback). However, little is known about how intra- and interspecific plant–soil feedbacks influence interspecific plant competition. Here, we used plants and soil from

  9. The influence of wildfire severity on soil char composition and nitrogen dynamics

    Science.gov (United States)

    Rhoades, Charles; Fegel, Timothy; Chow, Alex; Tsai, Kuo-Pei; Norman, John, III; Kelly, Eugene

    2017-04-01

    Forest fires cause lasting ecological changes and alter the biogeochemical processes that control stream water quality. Decreased plant nutrient uptake is the mechanism often held responsible for lasting post-fire shifts in nutrient supply and demand, though other upland and in-stream factors also likely contribute to elevated stream nutrient losses. Soil heating, for example, creates pyrogenic carbon (C) and char layers that influence C and nitrogen (N) cycling. Char layer composition and persistence vary across burned landscapes and are influenced first by fire behavior through the temperature and duration of combustion and then by post-fire erosion. To evaluate the link between soil char and stream C and N export we studied areas burned by the 2002 Hayman Fire, the largest wildfire in Colorado, USA history. We compared soil C and N pools and processes across ecotones that included 1) unburned forests, 2) areas with moderate and 3) high wildfire severity. We analyzed 1-2 cm thick charred organic layers that remain visible 15 years after the fire, underlying mineral soils, and soluble leachate from both layers. Unburned soils released more dissolved organic C and N (DOC and DON) from organic and mineral soil layers than burned soils. The composition of DOC leachate characterized by UV-fluorescence, emission-excitation matrices (EEMs) and Fluorescence Regional Integration (FRI) found similarity between burned and unburned soils, underscoring a common organic matter source. Humic and fulvic acid-like fractions, contained in regions V and III of the FRI model, comprised the majority of the fluorescing DOM in both unburned and char layers. Similarity between two EEMs indices (Fluorescence and Freshness), further denote that unburned soils and char layers originate from the same source and are consistent with visual evidence char layers contain significant amounts of unaltered OM. However, the EEMs humification index (HIX) and compositional analysis with pyrolysis GCMS

  10. Restoring Degraded Rangelands in Jordan: Optimizing Mechanized Micro-Water Harvesting Technique Using Rangeland Hydrology and Erosion Model (RHEM)

    Science.gov (United States)

    Continuous population growth, recent refugee movement and migration as well as boundary restrictions and their implications on the nomadic lifestyle are additive pressure on rangelands throughout the Middle East. In particular, overgrazing through increased livestock herds threatens the Jordanian ra...

  11. Soil biotic legacy effects of extreme weather events influence plant invasiveness.

    Science.gov (United States)

    Meisner, Annelein; De Deyn, Gerlinde B; de Boer, Wietse; van der Putten, Wim H

    2013-06-11

    Climate change is expected to increase future abiotic stresses on ecosystems through extreme weather events leading to more extreme drought and rainfall incidences [Jentsch A, et al. (2007) Front Ecol Environ 5(7):365-374]. These fluctuations in precipitation may affect soil biota, soil processes [Evans ST, Wallenstein MD (2012) Biogeochemistry 109:101-116], and the proportion of exotics in invaded plant communities [Jiménez MA, et al. (2011) Ecol Lett 14:1277-1235]. However, little is known about legacy effects in soil on the performance of exotics and natives in invaded plant communities. Here we report that drought and rainfall effects on soil processes and biota affect the performance of exotics and natives in plant communities. We performed two mesocosm experiments. In the first experiment, soil without plants was exposed to drought and/or rainfall, which affected soil N availability. Then the initial soil moisture conditions were restored, and a mixed community of co-occurring natives and exotics was planted and exposed to drought during growth. A single stress before or during growth decreased the biomass of natives, but did not affect exotics. A second drought stress during plant growth resetted the exotic advantage, whereas native biomass was not further reduced. In the second experiment, soil inoculation revealed that drought and/or rainfall influenced soil biotic legacies, which promoted exotics but suppressed natives. Our results demonstrate that extreme weather events can cause legacy effects in soil biota, promoting exotics and suppressing natives in invaded plant communities, depending on the type, frequency, and timing of extreme events.

  12. CO2 efflux from soil under influence of cadmium and glucose

    Science.gov (United States)

    Gilmullina, Aliia; Galitskaya, Polina; Selivanovskaya, Svetlana

    2017-04-01

    Soil is the largest pool of organic carbon. Any anthropogenic activity may change the soil organic carbon stock resulting in the atmospheric carbon concentration increase. Organic wastes and sewage sludge are often used for soil fertilization. These amendments often contain not only organic compounds stimulating soil microflora but also toxic compounds e.g. metals inhibiting them. The question about the influence of such amendments on soil carbon stock still remains open. The aim of this study was to evaluate individual glucose and cadmium (Cd) additions and their combined effects on carbon mineralization and microbial community structure in forest soil sampled from different depths (0-20 cm, 20-40 cm and 40-60 cm). We incubated soil samples for 14 days after the addition of: glucose (10000 mg kg-1), Cd (300 mg kg-1) and their mixture. CO2 efflux was measured by CO2 trapping in NaOH, at the 3rd, 7th and 14th days of incubation DNA was extracted from soil samples for assessment of microbial community structure via real-time PCR and Illumina sequencing. Glucose addition induced the increase of soil respiration and fungal-bacterial ratio. However, bacterial alpha-biodiversity decreased as glucose addition caused the dominance of Proteobacteria (0-20 cm, 20-40 cm and 40-60 cm), Actinobacteria (20-40 cm) and Acidobacteria (40-60 cm) phyla. Single Cd addition did not have any effect on parameters studied. In case of simultaneous addition of glucose and Cd, soil respiration and microbial community structure mainly depended more on glucose amendment as compared with metal.

  13. The Influence of Processing Soil With a Coffee Grinder on Soil Classification

    Science.gov (United States)

    2015-01-20

    one: Abstract Tech Report Journal Article Speech Paper Presentation Poster Book Other:_journal technical note (shorter than an article) Description...For submission for consideration for publication in the ASTM Journal of Geotechnical TEsting 3. DISCUSSION. NIA 4. VIEWS OF OTHERS. NIA 5... pestle , which can be used to grind down hard clods into much finer material. The mortar and pestle also allows separation of true aggregate from soil

  14. Influence of stand density on soil CO2 efflux for a Pinus densiflora forest in Korea.

    Science.gov (United States)

    Noh, Nam Jin; Son, Yowhan; Lee, Sue Kyoung; Yoon, Tae Kyung; Seo, Kyung Won; Kim, Choonsig; Lee, Woo-Kyun; Bae, Sang Won; Hwang, Jaehong

    2010-07-01

    We investigated the influence of stand density [938 tree ha(-1) for high stand density (HD), 600 tree ha(-1) for medium stand density (MD), and 375 tree ha(-1) for low stand density (LD)] on soil CO(2) efflux (R (S)) in a 70-year-old natural Pinus densiflora S. et Z. forest in central Korea. Concurrent with R (S) measurements, we measured litterfall, total belowground carbon allocation (TBCA), leaf area index (LAI), soil temperature (ST), soil water content (SWC), and soil nitrogen (N) concentration over a 2-year period. The R (S) (t C ha(-1) year(-1)) and leaf litterfall (t C ha(-1) year(-1)) values varied with stand density: 6.21 and 2.03 for HD, 7.45 and 2.37 for MD, and 6.96 and 2.23 for LD, respectively. In addition, R (S) was correlated with ST (R (2) = 0.77-0.80, P influenced R (S) via changes in leaf litterfall, LAI and SWC. Leaf litterfall (R (2) = 0.71), TBCA (R (2) = 0.64-0.87), and total soil N contents in 2007 (R (2) = 0.94) explained a significant amount of the variance in R (S) (P factors influencing R (S) due to the changing biophysical and environmental factors in P. densiflora.

  15. Soils

    Science.gov (United States)

    Emily Moghaddas; Ken Hubbert

    2014-01-01

    When managing for resilient forests, each soil’s inherent capacity to resist and recover from changes in soil function should be evaluated relative to the anticipated extent and duration of soil disturbance. Application of several key principles will help ensure healthy, resilient soils: (1) minimize physical disturbance using guidelines tailored to specific soil types...

  16. Organic amendments' dissolved organic carbon influences bioavailability of agricultural soil DOC

    Science.gov (United States)

    Straathof, Angela L.; Chincarini, Riccardo; Hoffland, Ellis; Comans, Rob N. J.

    2013-04-01

    microplate (Microresp™) as well as photoacoustically from incubated headspace. Fractions of soil DOC were measured at 5 timepoints. Total DOC decreased throughout the incubation as well as, interestingly, pools of humic acids. We postulate that this is due to low aromaticity of the added C source. Composts with different hydrophilic proportions ranged in their effects on soil DOC pool sizes and turnover. This suggests that more knowledge about the nature of the amendment is needed before predicting the influence it will have on soil microbial activity when applied in the field.

  17. Influence of storm characteristics on soil erosion and storm runoff

    Science.gov (United States)

    Johnny M. III Grace

    2008-01-01

    Unpaved forest roads can be major sources of sediment from forested watersheds. Storm runoff from forest roads are a concern due to their potential delivery of sediments and nutrients to stream systems resulting in degraded water quality. The volume and sediment concentrations of stormwater runoff emanating from forest roads can be greatly influenced by storm...

  18. Soil moisture influences the development of Haemonchus contortus and Trichostrongylus colubriformis to third stage larvae.

    Science.gov (United States)

    Khadijah, S; Kahn, L P; Walkden-Brown, S W; Bailey, J N; Bowers, S F

    2013-09-01

    Two climate chamber experiments were conducted to determine the effect of varying initial soil moisture (0, 10 and 15%), simulated rainfall amount (0, 12 and 24 mm) and simulated rainfall timing (days -1, 0 and 3 relative to faecal deposition) on development (day 14) of Haemonchus contortus and Trichostrongylus colubriformis to the third stage larvae (L3) and faecal moisture (FM). Increasing initial soil moisture content from 0 to 10 or 15% led to higher recovery of total L3 (Pmoisture and simulated rainfall amount on the recovery of total L3, showing that the benefit of increased simulated rainfall lessened with increasing soil moisture. Simulated rainfall on the day of deposition resulted in higher recovery of L3 (Prelative to faecal deposition was best associated with recovery of total H. contortus and T. colubriformis L3 (R(2)=0.32-0.46), reinforcing the importance of sufficient moisture soon after faecal deposition. The effects of initial soil moisture, and the amount and timing of simulated rainfall on development to L3 were largely explained by changes to FM and soil moisture values within 4 days relative to faecal deposition. These results highlight the influence of soil moisture and its interaction with rainfall on development of H. contortus and T. colubriformis to L3. Consequently we recommend that soil moisture be given greater importance and definition in the conduct of ecological studies of parasitic nematodes, in order to improve predictions of development to L3. Copyright © 2013 Elsevier B.V. All rights reserved.

  19. Influence of Water Content on the Flow Consistency of Dredged Marine Soils

    Directory of Open Access Journals (Sweden)

    Rosman M. Z.

    2016-01-01

    Full Text Available In present time, dredged marine soils (DMS are generally considered as geo-waste in Malaysia. It is also known to contain high value of water and low shear strength. Lightly solidified soils such as soilcement slurry and flowable fill are known as controlled low strength materials (CLSM. On site, the CLSM was tested for its consistency by using an open-ended cylinder pipe. The vertical and lateral displacement from the test would determine the quality and workability of the CLSM. In this study, manufactured kaolin powder was mixed with different percentages of water. Cement was also added to compare the natural soil with solidified soil samples. There are two methods of flowability test used, namely the conventional lift method and innovative drop method. The lateral displacement or soil spread diameter values were recorded and averaged. Tests showed that the soil spread diameter corresponded almost linear with the increasing amount of water. The binder-added samples show no significant difference with non-binder sample. Also, the mixing water content and percentage of fines had influenced the soil spread diameter.

  20. [Characteristics and influencing factors of trichloroethylene adsorption in different soil types].

    Science.gov (United States)

    He, Long; Qiu, Zhao-Fu; Lü, Shu-Guang; Lu, Zhi-Chang; Wang, Zhi-Li; Sui, Qian; Lin, Kuang-Fei; Liu, Yong-Di

    2012-11-01

    Adsorption plays an important role in the transport and the fate of trichloroethylene (TCE) in soil. Six types of soil, including two types of natural soil with different organic carbon content and four types of soil with the low aggregation of "soft carbon" pre-treated by hydrogen peroxide or with all organic carbon removed by high temperature ignition from the original soil, were adopted as adsorbents. The effects of parameters (organic carbon content and composition, minerals, the initial TCE concentration, solution pH, moisture content and ionic strength) on TCE adsorption capacity were examined. The results showed that the soil adsorption isotherm was non-linear within the experimental range. The TCE adsorption capacity was increased and the contribution rate of the minerals to the sorption was reduced with the increase of the organic carbon content. The adsorption of TCE in the soil was the result of the combined action of both organic carbon and minerals, in which organic carbon played a major part, whereas the role of minerals could not be neglected. As the initial TCE concentration increased, the contribution rate of the minerals to the sorption went down. The adsorption isotherm of "soft carbon" was linear, while the "hard carbon" was non-linear. Moreover, the adsorption capacity was increased by increasing the ionic strength. In contrast, neither pH nor moisture content had any influence on TCE adsorption.

  1. Influence of industrial heavy metal pollution on soil free-living nematode population

    Energy Technology Data Exchange (ETDEWEB)

    Pen-Mouratov, Stanislav [The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900 (Israel); Shukurov, Nosir [Institute of Geology and Geophysics, Academy of Sciences, Tashkent 700041 (Uzbekistan); Steinberger, Yosef [The Mina and Everard Goodman Faculty of Life Sciences, Bar-Ilan University, Ramat-Gan 52900 (Israel)], E-mail: steinby@mail.biu.ac.il

    2008-03-15

    The effect of distance from a heavy metal pollution source on the soil nematode community (trophic structure, sex structure, and taxa composition) was investigated along a 15-km transect originating at the Almalyk Industrial Complex, Uzbekistan (pollution source). The soil nematode community was exposed to heavy metal influence both directly and through soil properties changes. Pollution effect on the density and biomass of soil free-living nematodes was found to be highest at pollution source, with fungivores and plant parasites dominating at the upper and deeper soil layers next to the pollution source. These groups decreased along the transect, yielding domination to bacteria- and fungi-feeders. The sex ratio of nematode communities was found to be dependent on heavy metal pollution levels, with the juveniles being the most sensitive nematode group. The Maturity and modified Maturity Indices, reflecting the degree of disturbance of the soil ecosystem, were found to be the most sensitive indices. - Trophic structure and sex ratio of soil nematode population are sensitive tools for monitoring industrial pollution.

  2. Using optical-microwave synergy for estimating surface energy fluxes over semi-arid rangeland

    Science.gov (United States)

    Troufleau, D.; Vidal, A.; Beaudoin, A.; Moran, M. S.; Weltz, M. A.; Goodrich, D. C.; Washburn, J.; Rahman, A. F.

    1994-01-01

    First results of the Walnut Gulch '92 (Arizona, U.S.) experiment concerning the combined use of radar backscattering (ERS-1) and thermal infrared (LANDSAT TM (Thematic Mapper)) data to estimate surface sensible heat flux are reported. The first step investigates the potential use of ERS-1 SAR (Synthetic Aperture Radar) images for surface soil moisture monitoring of the watershed using five calibrated images acquired during the year 1992 (dry to wet conditions). Results show that despite the typical low level of biomass of semi arid rangeland, an attenuation of the soil backscatter (up to 2 dB) can occur during the rainy season mainly due to the vegetation characteristics. A statistical relationship is then used to retrieve the volumetric surface soil moisture from ERS-1 backscattering (sensitivity of 0.23 dB/% moisture) with a resulting root mean square error of 1.3% of soil moisture. In a second step a semi empirical approach based on energy balance relates soil temperatures to this estimated surface soil moisture. Vegetation temperature is then deduced from soil temperatures and LANDSAT TM composite temperature in order to estimate sensible heat flux according to a two layer type model providing an RMSE of 29 W/sq m.

  3. Influence of stone content on soil hydraulic properties: experimental investigation and test of existing model concepts

    Science.gov (United States)

    Naseri, Mahyar; Richter, Niels; Iden, Sascha C.; Durner, Wolfgang

    2017-04-01

    Rock fragments in soil, in this contribution referred to as "stones", play an important role for water flow in the subsurface. To successfully model soil hydraulic processes such as evaporation, redistribution and drainage, an understanding of how stones affect soil hydraulic properties (SHP) is crucial. Past investigations on the role of stones in soil have focused on their influence on the water retention curve (WRC) and on saturated hydraulic conductivity Ks, and have led to some simple theoretical models for the influence of stones on effective SHP. However, studies that measure unsaturated SHP directly, i.e., simultaneously the WRC and hydraulic conductivity curve (HCC) are still missing. Also, studies so far were restricted to low or moderate stone contents of less than 40%. We conducted a laboratory study in which we examined the effect of stone content on effective WRC and HCC of stony soils. Mixtures of soil and stones were generated by substituting background soil with stones in weight fractions between 0% (fine material only) to 100% (pure gravel). Stone sizes were 2-5 mm and 7-15 mm, respectively, and background soils were Sand and Sandy Loam. Packed samples were fully saturated under vacuum and subsequently subjected to evaporation in the laboratory. All experiments were done in three replicates. The soil hydraulic properties were determined by the simplified evaporation method using the UMS HYPROP setup. Questions were whether the applied measurement methodology is applicable to derive the SHP of the mixtures and how the gradual increase of stone content will affect the SHP, particularly the HCC. The applied methodology was successful in identifying effective SHP with a high precision over the full moisture range. WRC and HCC were successfully obtained by HYPROP, even for pure gravel with a size of 7-15 mm. WRCs changed qualitatively in the expected manner, i.e., an increase of stone content reduced porosity and soil water content at all suctions

  4. Influence of soil temperature on growth traits of European beech seedlings

    OpenAIRE

    Štraus, Ines; Frederick, Peter C.; Hylton, Becky; Mrak, Tanja; Ferlan, Mitja; Heath, Julie; Železnik, Peter; Spalding, Marilyn; Kraigher, Hojka

    2014-01-01

    European beech (Fagus sylvatica L.) is an economically and ecologically important forest tree species in Europe. Expected future temperature increases due to global climate change may significantly affect growth of beech trees and consequently influence carbon cycling in beech forests. We tested the hypothesis that soil temperature influences the growth of both belowground and aboveground parts of beech seedlings. One-year-old seedlings were transferred into rhizotrons and subjected ...

  5. Influence of organic waste type and soil structure on the bacterial filtration rates in unsaturated intact soil columns.

    Science.gov (United States)

    Mosaddeghi, M R; Mahboubi, A A; Zandsalimi, S; Unc, A

    2009-02-01

    Organic wastes are considered to be a source for the potentially pathogenic microorganisms found in surface and sub-surface water resources. Following their release from the organic waste matrix, bacteria often infiltrate into soil and may be transported to significant depths contaminating aquifers. We investigated the influence of soil texture and structure and most importantly the organic waste properties on the transport and filtration coefficients of Escherichia coli and total bacteria in undisturbed soil columns. Intact soil columns (diameter 16 cm and height 25 cm) were collected from two soils: sandy clay loam (SCL) and loamy sand (LS) in Hamadan, western Iran. The cores were amended with cow manure, poultry manure and sewage sludge at a rate of 10 Mg ha(-1) (dry basis). The amended soil cores were leached at a steady-state flux of 4.8 cm h(-1) (i.e. 0.12 of saturated hydraulic conductivity of the SCL) to a total volume of up to 4 times the pore volume of the columns. The influent (C(0)) and effluent (C) were sampled at similar time intervals during the experiments and bacterial concentrations were measured by the plate count method. Cumulative numbers of the leached bacteria, filtration coefficient (lambda(f)), and relative adsorption index (S(R)) were calculated. The preferential pathways and stable structure of the SCL facilitated the rapid transport and early appearance of the bacteria in the effluent. The LS filtered more bacteria when compared with the SCL. The effluent contamination of poultry manure-treated columns was greater than the cow manure- and sewage sludge-treated ones. The difference between cow manure and sewage sludge was negligible. The lambda(f) and S(R) values for E. coli and total bacteria were greater in the LS than in the SCL. This indicates a predominant role for the physical pore-obstruction filtration mechanisms as present in the poorly structured LS vs. the retention at adsorptive sites (chemical filtration) more likely in the

  6. Influence of forest disturbance on stable nitrogen isotope ratios in soil and vegetation profiles

    Science.gov (United States)

    Jennifer D. Knoepp; Scott R. Taylor; Lindsay R. Boring; Chelcy F. Miniat

    2015-01-01

    Soil and plant stable nitrogen isotope ratios (15 N) are influenced by atmospheric nitrogen (N) inputs and processes that regulate organic matter (OM) transformation and N cycling. The resulting 15N patterns may be useful for discerning ecosystem differences in N cycling. We studied two ecosystems; longleaf pine wiregrass (...

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

    Science.gov (United States)

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

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

    Science.gov (United States)

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

  9. Influence of modelled soil biogenic NO emissions on related trace gases and the atmospheric oxidizing capacity

    NARCIS (Netherlands)

    Steinkamp, J.; Ganzeveld, L.N.; Wilcke, W.; Lawrence, M.G.

    2009-01-01

    The emission of nitric oxide (NO) by soils (SNOx) is an important source of oxides of nitrogen (NOx=NO+NO2) in the troposphere, with estimates ranging from 4 to 21 Tg of nitrogen per year. Previous studies have examined the influence of SNOx on ozone (O-3) chemistry. We employ the ECHAM5/MESSy

  10. Geologic and edaphic factors influencing susceptibility of forest soils to environmental change

    Science.gov (United States)

    Scott W. Bailey

    2000-01-01

    There is great diversity in the structure and function of the northern forest across the 20-state portion of the United States considered in this book. The interplay of many factors accounts for the mosaic of ecological regimes across the region. In particular, climate, physiography, geology, and soils influence dominance and distribution of vegetation communities...

  11. Influence of soil and water conservation techniques on yield of small ...

    African Journals Online (AJOL)

    The study determined the application of soil and water conservation techniques in relation to yield of small-holder swamp rice farmers in Imo State, Nigeria in 2009. Specifically, the socio-economic characteristics of the farmer were described, their influence on the application of the techniques examined and relationship of ...

  12. Reindeer grazing in subarctic boreal forest - influences on the soil carbon dynamics

    Science.gov (United States)

    Koster, Kajar; Berninger, Frank; Köster, Egle; Pumpanen, Jukka

    2015-04-01

    ungrazed area. Also there was no significant differences in the soil CO2 efflux between the grazed and ungrazed area. This means that although the soil CO2 efflux was mostly lower in the ungrazed area, reindeer herding had no significant influence on the soil CO2 efflux. The CO2 effluxes were lowest in June. In July and August, the CO2 effluxes were more than two times higher compared to June. The microbial biomass C (Cmic) measured from humus horizon was lower in the grazed areas compared to the ungrazed areas, but the difference was not statistically significant. However, the microbial biomass N (Nmic) was significantly lower (p > 0.05) in the grazed areas compared to the ungrazed areas. We found also that grazing decreased significantly the biomass and cover of lichens in the coniferous forests. In Sodankylä the biomass of lichens was decreased around 74% due to grazing. In Värriö the decrease was even bigger, there the amount of lichen biomass was decreased more than 90% due to reindeer grazing. Ttal above ground biomass was higher in the area where no reindeer grazing had occurred. Moreover, the tree biomass was higher in the area with no grazing and tree regeneration was heavily affected by grazing, as we had much less tree regeneration in the grazed areas compared to the ungrazed areas.

  13. Study of the influence of temperature the venting depollution process of soils contaminated with volatile organic compounds

    OpenAIRE

    GABRIELA-ALINA BRUSTUREAN; JEAN CARRÉ; DELIA PERJU; TEODOR TODINCA

    2006-01-01

    Venting is one of the most used in situ remediation methods for unsaturated soils contaiminated with volatile organic compounds (VOC). The development of mathematical models and their validation by means of experimental results allowed the identification of the main parameters which influence the soil depollution process. The influence of temperature on the venting depollution process of soils polluted with volatile organic compounds was studied in this investigation. It was found that the de...

  14. Influence of Robinia pseudoacacia short rotation coppice on soil physical properties

    Science.gov (United States)

    Xavier, Morvan; Isabelle, Bertrand; Gwenaelle, Gibaud

    2015-04-01

    Human activities can lead to the degradation of soil physical properties. For instance, machinery traffic across the land can induce the development of compacted areas at the wheel tracks. It leads to a decrease in porosity which results in a decrease of the hydraulic conductivity, and therefore, prevents water infiltration and promotes surface runoff. Land use, soil management and soil cover also have a significant influence on soil physical properties (Kodesova et al., 2011). In the arable land, surface runoff and soil erosion are enhanced by the absence of soil cover for part of the year and by the decrease of aggregate stability due to a decline of soil organic matter. In that context, few studies focused on the effects of a Robinia pseudoacacia short rotation coppice (SRC) on soil physical properties. Therefore, this study aims to determine the effect of the conversion of a grassland in a SRC on soil physical properties. These properties have also been compared to those of arable land and natural forest. For that, in several plots of the experimental farm of Grignon (30 km west of Paris, France), different measurements were performed: i) soil water retention on a pressure plate apparatus for 7 water potential between 0 and 1500 kPa, ii) bulk density using the method for gravelly and rocky soil recommended by the USDA, iii) aggregate stability using the method described in Le Bissonnais (1996), and iv) soil hydraulic conductivity using a Guelph permeameter. All these measurements were performed on the same soil type and on different land uses: arable land (AL), grassland (GL), natural forest (NF) and short rotation coppice (SRC) of Robinia pseudoacacia planted 5 years ago. Soil water retention measurements are still under progress and will be presented in congress. Bulk density measurements of the AL, GL and SRC are not significantly different. They ranged from 1.32 to 1.42. Only the NF measurements are significantly lower than the other (0.97). Aggregate

  15. Influence of mycorrhizal fungi on fate of E. coli 0157:H7 in soil and Salmonella in soil and internalization into romaine lettuce plants

    Science.gov (United States)

    The objectives of this study were to determine the influence of arbuscular mycorrhizal (AM) fungi on persistence of Salmonella and enterohemorrhagic E. coli O157:H7 (EHEC) within soil, and survival within Romaine lettuce. Romaine seedlings were grown with or without AM fungi, i.e., soil fungi that ...

  16. Vegetation Influences on Long-Term Carbon Stabilization in Soils: a Coast Redwood-Prairie Comparison

    Science.gov (United States)

    Mambelli, S.; Burton, S. D.; McFarlane, K. J.; Torn, M. S.; Dawson, T. E.

    2010-12-01

    Complex interactions and feedbacks among soil, biota, climate, and parent material determine the long-term pathways and mechanisms of carbon persistence in soils. While it is well known that litter chemistry influences litter decay on annual-decadal timescales, its impact on long-term SOM storage is still under debate. We tested the role of the substrate available to decomposers in determining decomposition and sequestration of carbon by comparing two contrasting ecosystems representing end-members in terms of tissue lifespan and litter recalcitrance, an old-growth redwood forest and an adjacent tree-less prairie, at one site with identical climate, topography, and parent material. Solid-state CP MAS 13C NMR was applied to investigate the chemical structure of vegetation tissues (aboveground and belowground), and of soil fractions (particulate organic carbon free in the soil matrix and particulate organic carbon located inside soil aggregates, or free and occluded light fraction (LF), respectively) at different depths. In addition, the carbon stability of these soil density fractions was estimated based on radiocarbon modeling. Preliminary NMR results showed strong differences between redwood and prairie tissues, and between litters and surface soil fractions. On average, redwood litter contained more aromatic carbon (C and O substituted aryl C), more lipids (alkyl C) and fewer carbohydrates (O-alkyl C) than prairie litter. Under both vegetation types we found that the chemical structure changed consistently from litter to free LF, and from free LF to occluded LF. The alkyl C signal intensity increased, while the O-alkyl C fraction decreased, but more strongly at the redwood forest. The proportion of aromatic functional groups in the total organic matter (aromaticity) was always higher in the soil fractions compared with the original litters. Redwood soil fractions aromaticity was 0.32 (+80% from litter), while prairie soil fractions aromaticity varied from 0

  17. Influence of calcium and magnesium salts on acid soil chemistry and calcium nutrition of apple

    Energy Technology Data Exchange (ETDEWEB)

    Pavan, M.A.; Bingham, F.T.; Peryea, F.J.

    Field experiments were conducted in two Brazilian orchards to examine the effects of soil applications of calcitic lime (Ca-lime), phosphogypsum, CaCl/sub 2/, and magnesite (Mg-lime) on soil chemistry and Ca nutrition of apple (Malus domestica Borkh, cv. Gala/MM 106). One orchard was on a low Ca, high Al Inceptisol; the second orchard was on a low Ca, low Al Oxisol. The resulting soil chemical changes were strongly influenced by the initial soil chemistry and the composition of the soil amendments. The effects of Ca-lime, added at a rate calculated to neutralize the topsoil exchange acidity, were restricted primarily to the upper 20 cm of the soil, where it increased pH, increased total dissolved and exchangeable Ca, eliminated dissolved Al, and reduced exchangeable Al. Phosphogypsum, added at Ca rates equivalent to the Ca-lime treatment, slightly reduced soil pH in the Inceptisol and slightly increased soil pH in the Oxisol. Phosphogypsum did not appreciably affect dissolved Al in the topsoil; however, it did reduce exchangeable Al but to a lesser degree than did Ca-lime or Mg-lime. Phosphogypsum increased exchangeable Ca and decreased exchangeable Al in the subsoil to a depth of 40 to 60 cm. Calcium chloride, added at Ca rates equivalent to the Ca-lime treatment, produced dissolved and exchangeable Ca increases similar to the phosphogypsum treatment; however, soluble and exchangeable Al were increased and pH slightly decreased through out the soil profiles.

  18. The influence of rice husk and tobacco waste biochars on soil quality

    Directory of Open Access Journals (Sweden)

    Amir Hamzah

    2017-10-01

    Full Text Available Heavy metal pollution in agricultural land threatens soil and food quality. Soil pollution could be remediate using biochar, but the effectiveness of biochar on soil quality improvement is determined by types of feedstock and pyrolysis temperature. This study was aimed to explore the effect of different types of biochar on soil properties.  Biochar from rice husk and tobacco waste was applied to soil contaminated with lead and mercury. This study was conducted at Sumber Brantas, Malang East Java, and used a completely randomized design with three replicates. Heavy metals content was measured using AAS. The results of measurements were analyzed using analysis of variance at 5% and 1% significance levels. The initial analysis of the soil properties at the research site showed that the soil nutrient status was low, i.e. N (0.2 %, K (0.50 cmol+/kg, and CEC (5.9 me/100g respectively, but soil pH was neutral (6.8. The research site also has crossed the threshold of heavy metal content for Hg (0.5 ppm, Pb (25.22 ppm, Cd (1.96 ppm, and As (0.78 ppm. Biochar added had a positive influence on soil characteristics improvement. It could increase the content of organic C, i.e. 35.12% and 31.81% and CEC (cation exchange capacity, i.e.30.56 me/100g and 28.13 me/100 g for rice husk biochar and tobacco waste biochar, respectively.  However, N, P, and K contents were low i.e. N ( 0.33 and 0.30 %; P2O5 (148.79 and 152 ppm; K (1.58 and 2.11 mg/100g for rice husk biochar and tobacco waste biochar, respectively.

  19. Integrating a rangeland health assessment with successional management: A synergistic approach to EBIPM

    Science.gov (United States)

    Qualitative Rangeland Health Assessments are extremely useful because they provide a relative indication of resource problems on rangelands. Additionally, theSuccessional Management framework identifies three primary causes of plantcommunity change, ecological processes, and factors that modify thes...

  20. An Integrated Social, Economic, and Ecologic Conceptual (ISEEC) framework for considering rangeland sustainability

    Science.gov (United States)

    Fox, W.E.; McCollum, D.W.; Mitchell, J.E.; Swanson, L.E.; Kreuter, U.P.; Tanaka, J.A.; Evans, G.R.; Theodore, Heintz H.; Breckenridge, R.P.; Geissler, P.H.

    2009-01-01

    Currently, there is no standard method to assess the complex systems in rangeland ecosystems. Decision makers need baselines to create a common language of current rangeland conditions and standards for continued rangeland assessment. The Sustainable Rangeland Roundtable (SRR), a group of private and public organizations and agencies, has created a forum to discuss rangeland sustainability and assessment. The SRR has worked to integrate social, economic, and ecological disciplines related to rangelands and has identified a standard set of indicators that can be used to assess rangeland sustainability. As part of this process, SRR has developed a two-tiered conceptual framework from a systems perspective to study the validity of indicators and the relationships among them. The first tier categorizes rangeland characteristics into four states. The second tier defines processes affecting these states through time and space. The framework clearly shows that the processes affect and are affected by each other. ?? 2009 Taylor & Francis Group, LLC.

  1. Land management implications for ecosystem services in a South African rangeland

    NARCIS (Netherlands)

    Petz, K.; Glenday, J.; Alkemade, J.R.M.

    2014-01-01

    In South Africa, restoration and sustainable management of historically overgrazed and degraded rangelands are promoted to increase biodiversity and ecosystem service provision. This study evaluates different land management scenarios in terms of ecosystem services in a South African rangeland, the

  2. Very High Resolution Panoramic Photography to Improve Conventional Rangeland Monitoring 1994

    Science.gov (United States)

    Rangeland monitoring often includes repeat photographs as a basis for documentation and although photographic equipment and electronics have been evolving rapidly, basic rangeland photo monitoring methods have changed little over time. Ground based digital photography is underutilized, especially s...

  3. The influence of organic-containing soil dust on ice nucleation and cloud properties

    Science.gov (United States)

    Hummel, Matthias; Grini, Alf; Berntsen, Terje K.; Ekman, Annica

    2017-04-01

    Natural mineral dust from desert regions is known to be the most important contributor to atmospheric ice-nucleating particles (INP) which induce heterogeneous ice nucleation in mixed-phase clouds. Its ability to nucleate ice effectively is shown by various laboratory (Hoose and Möhler 2012) and field results (DeMott et al. 2015) and its abundance in ice crystal residuals has also been shown (Cziczo et al. 2013). Thus it is an important player when representing mixed-phase clouds in climate models. MODIS satellite data indicate that 1 /4 of the global dust emission originates from semi-arid areas rather than from arid deserts (Ginoux et al. 2012). Here, organic components can mix with minerals within the soil and get into the atmosphere. These so-called 'soil dust' particles are ice-nucleating active at high sub-zero temperatures, i.e. at higher temperatures than pure desert dust (Steinke et al. 2016). In this study, soil dust is incorporated into the Norwegian Earth System Model (NorESM, Bentsen et al. 2013) and applied to a modified ice nucleation parameterization (Steinke et al. 2016). Its influence on the cloud ice phase is evaluated by comparing a control run, where only pure desert dust is considered, and a sensitivity experiment, where a fraction of the dust emissions are classified as soil dust. Both simulations are nudged to ERA-interim meteorology and they have the same loading of dust emissions. NorESM gives a lower annual soil dust emission flux compared to Ginoux et al. (2012), but the desert dust flux is similar to the MODIS-retrieved data. Although soil dust concentrations are much lower than desert dust, the NorESM simulations indicate that the annual INP concentrations from soil dust are on average lower by a just a factor of 4 than INP concentrations from pure desert dust. The highest soil dust INP concentrations occur at a lower height than for desert dust, i.e at warmer temperatures inside mixed-phase clouds. Furthermore, soil dust INP

  4. Influence of Extractant and Soil Type on Molecular Characteristics of Humic Substances From Two Brazilian Soils

    Directory of Open Access Journals (Sweden)

    Dick Deborah Pinheiro

    1999-01-01

    Full Text Available In a previous study it was observed that humic substances (HS extracted with NaOH solution and with Na4P2O7 solution presented different molecular weights, and also that the extracted HS yield by each method varied between an Oxisol and a Mollisol from South Brazil. In the present study, we further investigated the organic matter in these soils by characterizing HS extracted with 0.5 mol L-1 NaOH and with neutral 0.15 mol L-1 Na4P2O7 solutions from the above mentioned samples, using elemental analysis and nuclear magnetic ressonance spectroscopy (liquid state ¹H- and 13C-NMR, and by relating the molecular differences to the extraction method and soil type. HS extracted with pyrophosphate were more humified, showing a higher aromaticity and higher carboxylic content. The NaOH-extracted HS were more aliphatic and contained a higher O-alkyl proportion, which is indicative of a less humified nature than the pyrophosphate-extracted HS.

  5. Temporal and spatial influences incur reconfiguration of Arctic heathland soil bacterial community structure.

    Science.gov (United States)

    Hill, Richard; Saetnan, Eli R; Scullion, John; Gwynn-Jones, Dylan; Ostle, Nick; Edwards, Arwyn

    2016-06-01

    Microbial responses to Arctic climate change could radically alter the stability of major stores of soil carbon. However, the sensitivity of plot-scale experiments simulating climate change effects on Arctic heathland soils to potential confounding effects of spatial and temporal changes in soil microbial communities is unknown. Here, the variation in heathland soil bacterial communities at two survey sites in Sweden between spring and summer 2013 and at scales between 0-1 m and, 1-100 m and between sites (> 100 m) were investigated in parallel using 16S rRNA gene T-RFLP and amplicon sequencing. T-RFLP did not reveal spatial structuring of communities at scales structuring effects may not confound comparison between plot-scale treatments, temporal change is a significant influence. Moreover, the prominence of two temporally exclusive keystone taxa suggests that the stability of Arctic heathland soil bacterial communities could be disproportionally influenced by seasonal perturbations affecting individual taxa. © 2015 Society for Applied Microbiology and John Wiley & Sons Ltd.

  6. Influence of pre-treatment step on PAHs analyses in contaminated soils.

    Science.gov (United States)

    Belkessam, Laurence; Lecomte, Paul; Milon, Véronique; Laboudigue, Agnès

    2005-01-01

    There is no specific standardization for the pre-treatment of a soil sample for PAHs analyses. The ISO/FDIS 14507 method for soil quality gives a guidance for sample pre-treatment before measurement of organic contaminants in soil. It refers to cryogenic crushing which is not so easy to carry out. So, analysts lead to develop in house methods which can be very different from a laboratory to another and can involve deviations in the pollution quantification. This study has explored different ways of drying, grinding and sieving in order to determine the influence of the soil sample handling on the measured pollutant concentration. It appears that the influence of pre-treatment depends on the soil nature and on the PAHs distribution. As a conclusion, it is advised "light" drying ways like air drying or drying at 40 degrees C in a drying oven instead of more "drastic" ways (freeze-drying, cryogenic crushing) which can induce some losses. Crushing and sieving are also recommended for more reproducible measures.

  7. Influence of industrial solid waste addition on properties of soil-cement bricks

    Directory of Open Access Journals (Sweden)

    F. B. Siqueira

    Full Text Available Abstract The reuse of pollutant solid wastes produced in distinct industrial activities (avian eggshell waste and welding flux slag waste as a source of alternative raw material for producing soil-cement bricks for civil construction was investigated. Soil-cement bricks containing up to 30 wt% of industrial solid waste were uniaxially pressed and cured for 28 days. Special emphasis is given on the influence of solid waste addition on the technical properties (as such volumetric shrinkage, water absorption, bulk density, durability, and compressive strength, microstructure and mineral phases of soil-cement bricks. Microstructural evolution was evaluated via confocal microscopy. The experimental results showed that the solid wastes behave as charge material and influenced both technical properties and microstructure of the soil-cement bricks. It was found that up to 15 wt% of welding flux slag waste and up to 30 wt% of avian eggshell waste could be added into the soil-cement bricks for use as building material.

  8. Influence of saturation degree and role of suction in unsaturated soils behaviour: application to liquefaction

    Directory of Open Access Journals (Sweden)

    Vernay Mathilde

    2016-01-01

    Full Text Available The effect of the pore fluid compressibility on liquefaction has been studied by various authors. But few papers have been published about the role of suction in cyclic behavior of unsaturated soils. Most of these works use Skempton coefficient B as a reference in terms of saturation degree to analyze their results. The use of B in experimental conditions is convenient, but is not accurate when studying liquefaction behavior, since effects of suction are neglected. In this paper, the influence of saturation degree on mechanical behavior of a soil under dynamic loads is studied. Cyclic undrained triaxial tests were performed on sand samples, under various levels of saturation. Soil-water characteristic curve was used, in order to study influence of suction. The first results confirm that when the degree of saturation decreases, the resistance increases. Initial positive suction tends to stiffen the soil. It also appears that the presence of air delays the occurrence of liquefaction, but doesn’t prevent it. Indeed, liquefaction is observed, whether the soil is saturated or not.

  9. Intrinsic factors of Peltigera lichens influence the structure of the associated soil bacterial microbiota.

    Science.gov (United States)

    Leiva, Diego; Clavero-León, Claudia; Carú, Margarita; Orlando, Julieta

    2016-11-01

    Definition of lichens has evolved from bi(tri)partite associations to multi-species symbioses, where bacteria would play essential roles. Besides, although soil bacterial communities are known to be affected by edaphic factors, when lichens grow upon them these could become less preponderant. We hypothesized that the structure of both the lichen microbiota and the microbiota in the soil underneath lichens is shaped by lichen intrinsic and extrinsic factors. In this work, intrinsic factors corresponded to mycobiont and cyanobiont identities of Peltigera lichens, metabolite diversity and phenoloxidase activity and extrinsic factors involved the site of the forest where lichens grow. Likewise, the genetic and metabolic structure of the lichen and soil bacterial communities were analyzed by fingerprinting. Among the results, metabolite diversity was inversely related to the genetic structure of bacterial communities of lichens and soils, highlighting the far-reaching effect of these substances; while phenoloxidase activity was inversely related to the metabolic structure only of the lichen bacterial microbiota, presuming a more limited effect of the products of these enzymes. Soil bacterial microbiota was different depending on the site and, strikingly, according to the cyanobiont present in the lichen over them, which could indicate an influence of the photobiont metabolism on the availability of soil nutrients. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. The influence of copper on tebuconazole sorption onto soils, humic substances, and ferrihydrite.

    Science.gov (United States)

    Čadková, Eva; Komárek, Michael; Kaliszová, Regina; Száková, Jiřina; Vaněk, Aleš; Bordas, François; Bollinger, Jean-Claude

    2013-06-01

    The aim of this study is to investigate how the presence of Cu influences tebuconazole (Teb) sorption onto contrasting soil types and two important constituents of the soil sorption complex: hydrated Fe oxide and humic substances. Tebuconazole was used in commercial form and as an analytical-grade chemical at different Teb/Cu molar ratios (1:4, 1:1, 4:1, and Teb alone). Increased Cu concentrations had a positive effect on tebuconazole sorption onto most soils and humic substances, probably as a result of Cu-Teb tertiary complexes on the soil surfaces. Tebuconazole sorption increased in the following order of different Teb/Cu ratios 1:4>1:1>4:1>without Cu addition, with the only exception for the Leptosol and ferrihydrite. The highest K f value was observed for humic substances followed by ferrihydrite, the Cambisol, the Arenosol, and the Leptosol. The sorption of analytical-grade tebuconazole onto all matrices was lower, but the addition of Cu supported again tebuconazole sorption. The Teb/Cu ratio with the highest Cu addition (1:4) exhibited the highest K f values in all matrices with the exception of ferrihydrite. The differences in tebuconazole sorption can be attributed to the additives present in the commercial product. This work proved the importance of soil characteristics and composition of the commercially available pesticides together with the presence of Cu on the behavior of tebuconazole in soils.

  11. Evaluating Structural and Functional Characteristics of Various Ecological Patches in Different Range Conditions (Case Study: Semi -Steppe Rangeland of Aghche-Isfahan

    Directory of Open Access Journals (Sweden)

    F. Jafari

    2015-03-01

    Full Text Available Rangeland condition assessment plays an important role in determining range health and applying appropriate management programs. This study aimed to evaluate the structure and function of a semi-steppe rangeland using Landscape Function Analysis technique (LFA in different land conditions in western Isfahan province, Iran. For this purpose, 4, 3 and 7 sites in different rangeland condition classes including very poor, poor, and moderate were selected respectively. In each site, a 30-meter transect was established and all kinds of patches and inter patches were identified and their lengths and widths were recorded. Also, in each ecological patch, 11 indicators of soil surface characteristics with three replications were measured, and their status was scored according to LFA method. The functionality indices of all the sites including soil stability, infiltration and nutrient cycling were measured. According to the statistical analysis results, most of the structural characteristics (number of patches, patch length, patch area index, landscape organization index and functional indices (infiltration, stability and nutrient cycling status varied significantly (α= 5% between rangeland sites with moderate and very poor condition. The changes of these structural and functional characteristics were not significant between range sites with moderate and poor, and also poor and very poor range conditions. According to the findings of this study, patch types' functionalities did not vary significantly in both rangeland sites with moderate and very poor conditions. The nutrient cycling index in patches formed by ‘forb, shrub and grass’ with poor range condition was significantly more than ‘forb’ and ‘grass’ patches. The study of range site functionality can assist managers in identifying possible ecological thresholds and prioritizing the sub-catchments and vegetation types for implementing range improvement practices.

  12. Rangelands of Central Asia: Proceedings of the Conference on Transformations, Issues, and Future Challenges

    Science.gov (United States)

    Donald J. Bedunah; E. Durant McArthur; Maria Fernandez-Gimenez

    2006-01-01

    The 11 papers in this document address issues and needs in the development and stewardship of Central Asia rangelands, and identify directions for future work. With its vast rangelands and numerous pastoral populations, Central Asia is a region of increasing importance to rangeland scientists, managers, and pastoral development specialists. Five of the papers address...

  13. Assessing the impacts of livestock production on biodiversity in rangeland ecosystems

    NARCIS (Netherlands)

    Alkemade, R.; Reid, R.S.; Berg, van den M.; Leeuw, de J.; Jeuken, M.

    2013-01-01

    Biodiversity in rangelands is decreasing, due to intense utilization for livestock production and conversion of rangeland into cropland; yet the outlook of rangeland biodiversity has not been considered in view of future global demand for food. Here we assess the impact of future livestock

  14. Ecologic, Economic, and Social Considerations for Rangeland Sustainability: An Integrated Conceptual Framework

    Science.gov (United States)

    Daniel W. McCollum; H. Theodore Jr. Heintz; Aaron J. Harp; John A. Tanaka; Gary R. Evans; David Radloff; Louis E. Swanson; William E. III Fox; Michael G. Sherm Karl; John E. Mitchell

    2006-01-01

    Use and sustainability of rangelands are inherently linked to the health and sustainability of the land. They are also inherently linked to the social and economic infrastructures that complement and support those rangelands and rangeland uses. Ecological systems and processes provide the biological interactions underlying ecosystem health and viability. Social and...

  15. Criterion IV: Social and economic indicators of rangeland sustainability (Chapter 5)

    Science.gov (United States)

    Daniel W. McCollum; Louis E. Swanson; John A. Tanaka; Mark W. Brunson; Aaron J. Harp; L. Allen Torell; H. Theodore Heintz

    2010-01-01

    Social and economic systems provide the context and rationale for rangeland management. Sustaining rangeland ecosystems requires attention to the social and economic conditions that accompany the functioning of those systems. We present and discuss economic and social indicators for rangeland sustainability. A brief conceptual basis for each indicator is offered,...

  16. Application of rangeland health indicators on forested plots on the Fishlake National Forest, Utah

    Science.gov (United States)

    Maggie G. Toone; Sara Goeking

    2017-01-01

    Typical indicators of rangeland health are used to describe health and functionality of a variety of rangeland ecosystems. Similar indicators may be applied to forested locations to examine ecological health at a local forest level. Four rangeland health indicators were adapted and applied to data compiled by the U.S. Department of Agriculture, Forest Service, Rocky...

  17. Invasive rangeland plants in range and animal sciences and resources management

    Science.gov (United States)

    Comprising about 50% of the world’s land surface, rangelands are an important ecological and economic resource. Rangeland plant communities are changing. Even though the composition of plant communities in rangeland changes continually through the process of succession, in more recent years this c...

  18. Endophytic fungal communities of Polygonum acuminatum and Aeschynomene fluminensis are influenced by soil mercury contamination.

    Science.gov (United States)

    Pietro-Souza, William; Mello, Ivani Souza; Vendruscullo, Suzana Junges; Silva, Gilvan Ferreira da; Cunha, Cátia Nunes da; White, James Francis; Soares, Marcos Antônio

    2017-01-01

    The endophytic fungal communities of Polygonum acuminatum and Aeschynomene fluminensis were examined with respect to soil mercury (Hg) contamination. Plants were collected in places with and without Hg+2 for isolation and identification of their endophytic root fungi. We evaluated frequency of colonization, number of isolates and richness, indices of diversity and similarity, functional traits (hydrolytic enzymes, siderophores, indoleacetic acid, antibiosis and metal tolerance) and growth promotion of Aeschynomene fluminensis inoculated with endophytic fungi on soil with mercury. The frequency of colonization, structure and community function, as well as the abundant distribution of taxa of endophytic fungi were influenced by mercury contamination, with higher endophytic fungi in hosts in soil with mercury. The presence or absence of mercury in the soil changes the profile of the functional characteristics of the endophytic fungal community. On the other hand, tolerance of lineages to multiple metals is not associated with contamination. A. fluminensis depends on its endophytic fungi, since plants free of endophytic fungi grew less than expected due to mercury toxicity. In contrast plants containing certain endophytic fungi showed good growth in soil containing mercury, even exceeding growth of plants cultivated in soil without mercury. The data obtained confirm the hypothesis that soil contamination by mercury alters community structure of root endophytic fungi in terms of composition, abundance and species richness. The inoculation of A. fluminensis with certain strains of stress tolerant endophytic fungi contribute to colonization and establishment of the host and may be used in processes that aim to improve phytoremediation of soils with toxic concentrations of mercury.

  19. Soil erosion influenced by wildfire and pre-fire plantation method in NW Spain

    Science.gov (United States)

    Fernández Filgueira, Cristina; Vega Hidalgo, José Antonio; Fonturbel Lliteras, Teresa

    2017-04-01

    Erosion is a major concern in areas affected by high-severity wildfires. Soil characteristics associated with past forestry management can play a significant role in post-wildfire soil loss through increments in soil erodibility or as a result of sediment exhaustion. In areas such as NW Spain where there is a long history of intensive land use, this factor may be critical for explaining soil loss after wildfire. The objective of this study was to determine whether plantation method can significantly influence soil loss in the first year after wildfire in a P. sylvestris plantation affected wildfire in NW Spain. For these purpose, we measured hillslope-scale sediment production rates and site characteristics during the first year after wildfire in 30 plots. Treatments consisted in pre-fire ploughing+ wildfire, plantation holes+ wildfire and no preparation method+wildfire. Soil burn severity was high as average. During the first year following fire, soil losses varied from 0.9 t/ha in the ploughed areas to 4.6 t/ha in the plantation wholes. The treatment with no terrain preparation yielded 3.0 t/ha during the same period of time. These results suggest that pre-fire ploughed areas are not a priority for soil erosion risk mitigation after wildfire. The study was funded by the National Institute of Agricultural Research of Spain (INIA) through project RTA2014-00011-C06-02, cofunded by FEDER and the Plan de Mejora e Innovación Forestal de Galicia (2010-2020) and INDITEX.

  20. Multispectral Remote Sensing from Unmanned Aircraft: Image Processing Workflows and Applications for Rangeland Environments

    Directory of Open Access Journals (Sweden)

    Albert Rango

    2011-11-01

    Full Text Available Using unmanned aircraft systems (UAS as remote sensing platforms offers the unique ability for repeated deployment for acquisition of high temporal resolution data at very high spatial resolution. Multispectral remote sensing applications from UAS are reported in the literature less commonly than applications using visible bands, although light-weight multispectral sensors for UAS are being used increasingly. . In this paper, we describe challenges and solutions associated with efficient processing of multispectral imagery to obtain orthorectified, radiometrically calibrated image mosaics for the purpose of rangeland vegetation classification. We developed automated batch processing methods for file conversion, band-to-band registration, radiometric correction, and orthorectification. An object-based image analysis approach was used to derive a species-level vegetation classification for the image mosaic with an overall accuracy of 87%. We obtained good correlations between: (1 ground and airborne spectral reflectance (R2 = 0.92; and (2 spectral reflectance derived from airborne and WorldView-2 satellite data for selected vegetation and soil targets. UAS-acquired multispectral imagery provides quality high resolution information for rangeland applications with the potential for upscaling the data to larger areas using high resolution satellite imagery.

  1. An overview of the rangelands atmosphere hydrosphere biosphere interaction study experiment in northeastern Asia (RAISE)

    Science.gov (United States)

    Sugita, Michiaki; Asanuma, Jun; Tsujimura, Maki; Mariko, Shigeru; Lu, Minjiao; Kimura, Fujio; Azzaya, Dolgorsuren; Adyasuren, Tsokhio

    2007-01-01

    SummaryIntensive observations, analysis and modeling within the framework of the rangelands atmosphere-hydrosphere-biosphere interaction study experiment in northeastern Asia (RAISE) project, have allowed investigations into the hydrologic cycle in the ecotone of forest-steppe, and its relation to atmosphere and ecosystem in the eastern part of Mongolia. In this region, changes in the climate have been reported and a market oriented economy was introduced recently, but their impact on the natural environment is still not well understood. In this RAISE special issue, the outcome is presented of the studies carried out by six groups within RAISE, namely: (1) Land-atmosphere interaction analysis, (2) ecosystem analysis and modeling, (3) hydrologic cycle analysis, (4) climatic modeling, (5) hydrologic modeling, and (6) integration. The results are organized in five relevant categories comprising (i) hydrologic cycle including precipitation, groundwater, and surface water, (ii) hydrologic cycle and ecosystem, (iii) surface-atmosphere interaction, (iv) effect of grazing activities on soils, plant ecosystem and surface fluxes, and (v) future prediction. Comparison with studies on rangelands in other parts of the world, and some future directions of studies still needed in this region are also summarized.

  2. Abandoned seasonal livestock migration reflected by plant functional traits: A case study in Kyrgyz rangelands

    Science.gov (United States)

    Hoppe, Franziska; Zhusui Kyzy, Taalaigul; Usupbaev, Adilet; Schickoff, Udo

    2017-04-01

    At least 30% of Kyrgyz pasture areas are considered to be subject to vegetation and soil degradation. Since animal husbandry is the economic basis to sustain people's livelihoods, rangeland degradation presents a threat for the majority of the population. Recently, the usage of plant functional traits as a powerful tool for the characterization of vegetation dynamics in response to anthropogenic and natural disturbances has been put forward. Grazing is one of the most severe disturbances on vegetation, which concerns equally the loss of area and biomass. Because grazing is both depending on and affecting plant functional traits, important insights can be generated, based on this codependency. We hypothesized that the contrasting grazing intensity of summer and winter pastures is reflected by the chosen traits. We used traits such as plant height, flowering start, growth form as well as SLA (Specific Leaf Area) and LMA (Leaf Mass per Area). Based on former phytosociological classification of the main pasture types (summer and winter pastures), community structure and the traits of dominant plant species were analyzed. Our results showed that on winter pastures grazing decreased plant height and SLA and favored plants with an earlier flowering start as well as rosette plants and ascending plants. We conclude that the study of trait composition in relation to anthropogenic disturbances can provide important insights into the mechanism of plant response to grazing in high-altitude rangelands.

  3. Influence of Calcium Carbonate on Cobalt Phytoavailability in Fluvo-aquic Soil

    Science.gov (United States)

    Wang, Mengyuan; Liu, Borui; Ma, Yufei; Xue, Qianhui; Huang, Qing

    2017-12-01

    In order to study the efficacy of calcium carbonate for cobalt (Co) fixation, as well as its influence on chemical speciation of Co in fluvo-aquic soil, pakchoies were planted in the soil with different quantities of exogenous Co and calcium carbonate. Co concentrations in the mature plant shoots were analyzed, and the chemical speciation of Co were detected with the Tessier five-step sequential extraction. The results showed that the Co concentration in plants tended to decrease first and then get higher with the concentration of calcium carbonate increasing (0-12g/kg) in soil (P plant reached to the lowest point, while the proportion of Co in the exchangeable form reached the minimum. In conclusion, to get the optimum effect, the dosage of calcium carbonate should be kept in the range of 5.0 to 7.5 g/kg when it is applied to Co fixation.

  4. The Characters of Dry Soil Layer on the Loess Plateau in China and Their Influencing Factors

    Science.gov (United States)

    Yan, Weiming; Deng, Lei; Zhong, Yangquanwei; Shangguan, Zhouping

    2015-01-01

    A dry soil layer (DSL) is a common soil desiccation phenomenon that generally forms at a particular depth in the soil profile because of climatic factors and poor land management, and this phenomenon can influence the water cycle and has been observed on the Loess Plateau of China and other similar regions around the world. Therefore, an investigation of the DSL formation depth (DSLFD), thickness (DSLT) and mean water content (MWDSL) on the Loess Plateau can provide valuable information. This paper synthesized 69 recent publications (1,149 observations of DSLs from 73 sites) that focused on DSLs in this region, and the results indicated that DSLs are significantly affected by climatic and vegetation factors. The mean annual precipitation had a significant positive relationship with DSLFD (p = 0.0003) and MWDSL (paffecting DSLs will provide information for use in guidelines for the sustainable development of economies and restoration of natural environments experiencing water deficiencies. PMID:26241046

  5. Water use efficiency of six rangeland grasses under varied soil ...

    African Journals Online (AJOL)

    African Journal of Environmental Science and Technology. Journal Home · ABOUT THIS JOURNAL · Advanced Search · Current Issue · Archives · Journal Home > Vol 9, No 7 (2015) >. Log in or Register to get access to full text downloads.

  6. Cover crops influence soil microorganisms and phytoextraction of copper from a moderately contaminated vineyard.

    Science.gov (United States)

    Mackie, K A; Schmidt, H P; Müller, T; Kandeler, E

    2014-12-01

    We investigated the ability of summer (Avena sativa [oat], Trifolium incarnatum [crimson clover], Chenopodium [goosefoot]) and winter (Vicia villosa [hairy vetch], Secale Cereale L. [Rye], Brassica napus L. partim [rape]) cover crops, including a mixed species treatment, to extract copper from an organic vineyard soil in situ and the microbial communities that may support it. Clover had the highest copper content (14.3mgCukg(-1) DM). However, it was the amount of total biomass production that determined which species was most effective at overall copper removal per hectare. The winter crop rye produced significantly higher amounts of biomass (3532kgDMha(-1)) and, therefore, removed significantly higher amounts of copper (14,920mgCuha(-1)), despite less accumulation of copper in plant shoots. The maximum annual removal rate, a summation of best performing summer and winter crops, would be 0.033kgCuha(-1)y(-1). Due to this low annual extraction efficiency, which is less than the 6kgCuha(-1)y(-1) permitted for application, phytoextraction cannot be recommended as a general method of copper extraction from vineyards. Copper concentration did not influence aboveground or belowground properties, as indicated by sampling at two distances from the grapevine row with different soil copper concentrations. Soil microorganisms may have become tolerant to the copper levels at this site. Microbial biomass and soil enzyme activities (arylsulfatase and phosphatase) were instead driven by seasonal fluxes of resource pools. Gram+ bacteria were associated with high soil moisture, while fungi seemed to be driven by extractable carbon, which was linked to high plant biomass. There was no microbial group associated with the increased phytoextraction of copper. Moreover, treatment did not influence the abundance, activity or community structure of soil microorganisms. Copyright © 2014 Elsevier B.V. All rights reserved.

  7. Modelling the influence of plants on the spatial heterogeneity of soil water

    Science.gov (United States)

    Malchow, Melanie; van Schaik, Loes; Tietjen, Britta

    2015-04-01

    Plants are sessile organisms and as such depend on sufficient local water supply. At the same time, plants themselves directly influence the spatial water distribution in the soil. Thus, plants partly regulate their own water supply. Current ecohydrological models apply simplified approaches to assess infiltration and the spatial distribution of water. They often neglect the influence of the vegetation the spatial heterogeneity in soil water. For example, the shape of the leafage and the rooting system strongly impact the amount of water that reaches the soil and how it is spatially distributed. If rainfall hits the leafage only a fraction of the water falls trough directly. The remaining fraction is intercepted and firstly accumulates on the leaves. This water either runs down the stem (stem flow) or evaporates directly. As a result, more water is received in the local environment of the stem than under the remaining canopy. The rooting system additionally influences the amount of infiltrated water and its distribution in the soil: Roots lead to preferential flow paths and form small caverns that increase the water storage capacity. In our work we developed a simulation model (using Netlogo) to track the path of rainfall from its first contact with the leafage to its storage in the soil. Our model structure supports simulations for different morphological plant types that allow us to evaluate the effect of branch structure, leaf density and the rooting system on water fluxes and thus local availability. The parameterization of morphological traits is based on 2-D profiles derived by simple image processing of pictures. This provides a highly flexible framework to evaluate different scenarios, which we aim to couple with a dynamic vegetation model in the future.

  8. CONSIDERATIONS REGARDING THE INFLUENCE OF METALIC IONS OF THE STABILITY OF CARBONATES FROM SOILS

    Directory of Open Access Journals (Sweden)

    D. Bulgariu

    2005-10-01

    Full Text Available The distribution of minor elements in heterogeneous mineral / aqueous solutions systems represent one of important problem, with many applications in environmental geochemistry field. Ours studies was focus on the metal ions distribution in carbonate (CaCO3 / solution systems, from applicability point of view to the estimation of formation conditions and of carbonates stability from soils. On the base of our results obtained by sequential solid / liquid extraction for 17 soil samples and theoretical modeling of CaCO3 / solution systems, and the results from literature we try to develop the McIntire prognosis models and the free Gibbs enthalpy linear correlation model, by the inclusion in calculus relations of distribution coefficients a higher number of factors which effective influenced the thermodynamics and kinetics of interphase distribution processes of metal ions. The established correlations has been used to the estimation of time evolution of carbonate / solution equilibrium under the influence of some metal ions (Cd, Zn, Cu, Pb, Bi, which appear usual as pollutants in soils. The prognosis realized on the base of the established correlations are in agreement with the theoretical modelling results and studies of case for different types of polluted soils with heavy metals.

  9. Soil and vegetation influence in plants natural radionuclides uptake at a uranium mining site

    Science.gov (United States)

    Charro, E.; Moyano, A.

    2017-12-01

    The main objective of this work is to investigate the uptake of several radionuclides by the vegetation characteristic of a dehesa ecosystem in uranium mining-impacted soils in Central-West of Spain. The activity concentration for 238U, 226Ra, 210Pb, 232Th, and 224Ra was measured in soil and vegetation samples using a Canberra n-type HPGe gamma-ray spectrometer. Transfer factors of natural radionuclides in different tissues (leaves, branches, twigs, and others) of native plants were evaluated. From these data, the influence of the mine, the physicochemical parameters of the soils and the type of vegetation were analyzed in order to explain the accumulation of radionuclides in the vegetation. A preferential uptake of 210Pb and 226Ra by plants, particularly by trees of the Quercus species (Quercus pyrenaica and Quercus ilex rotundifolia), has been observed, being the transfer factors for 226Ra and 210Pb in these tree species higher than those for other plants (like Pinus pinaster, Rubur ulmifolius and Populus sp.). The analysis of radionuclide contents and transfer factors in the vegetation showed no evidence of influence of the radionuclide concentration in soils, although it could be explained in terms of the type of plants and, in particular, of the tree's species, with special attention to the tree's rate of growth, being higher in slow growing species.

  10. Experimental study of the pH influence on the transport mechanisms of phenols in soil.

    Science.gov (United States)

    Fiore, Silvia; Zanetti, Maria Chiara; Genon, Giuseppe

    2003-01-01

    The study of the transport mechanisms connected to solid-liquid interactions is fundamental in the determination of the extension of the pollution of a site and in the evaluation of the best remediation process to be applied. The sorption of hydrophobic ionizable organic contaminants from the groundwaters is supervised not only by the physico-chemical properties of soil and pollutants, but also by the groundwaters pH, which deeply influences their solubility in the aqueous media, and consequently their transport mechanisms in the aquifer. In this work an experimental study of the sorption of phenol and 2-nitrophenol on two soils, different in particle-size distribution, CEC and organic carbon content, was realized. The sorption potential of the soils was evaluated by means of a physical, mineralogical and chemical characterization. The experimental data coming from some batch tests, performed at pH values equal to 4, 7 and 10 were fitted by means of linear, Freundlich and Langmuir isotherms models. The soil-contaminants interaction mechanisms that influence the isotherms shapes were then analyzed and discussed, and a comparison between the theoretical and experimental values of the partitioning coefficient KD was performed.

  11. INFLUENCE OF PHOSPHORUS AND ZINC APPLICATION ON SOIL NEMATODE COMMUNITY IN HOT PEPPER (CAPSICUM ANNUUM L.

    Directory of Open Access Journals (Sweden)

    Mirjana Brmež

    2014-06-01

    Full Text Available This research studied nematode communities in the soil during hot pepper cultivation and under influence of Zn and P fertilizer application. The aim of this study was to determine changes in soil nematode communities during the cultivation of hot pepper under the influence of P, Zn and their combination (P+Zn application. The study included the examination of changes in nematodes structure in soil, their total abundance, the total number of genera and analysis of trophic groups. Changes in nematode community were determined using the MI, MI 2–5, PPI and their ratio (PPI/MI. The diversity of the community was investigated using H’ index. Intensification in disturbance resulted in increased the total number of nematodes, as a result of reduction or elimination of the persisters in favor of colonizers, whereas larger disturbances decreased in genus richness soil nematode assemblages. The genera of nematodes which did not show sensitivity due to the presence of P and Zn are: Acrobeloides, Aphelenchoides, Aphelenchus, Dipterophora, Ditylenchus, Eucephalobus, Eudorylaimus, Mesodorylaimus, Paratylenchus, Plectus, Pratylenchus, Prodorylaimus, Rhabditis, Tylenchorhynchus and Tylenchus. The MI, PPI and PPI/MI did not significant distinguish the management regimes. The MI 2–5 was shown as an excelent parameter reflecting distress in nematode community structure. Omnivorous genera Panagrolaimus and Microdorylaimus were the most disturbance susceptible omnivores. Generally omnivorous were the most disturbance susceptible and their number reduced in all treatments by 50% compared to the control and according to that, omnivorous presents good parameter reflecting distress in nematode community.

  12. The influence comparing of activated biochar and conventional biochar on the soil biological properties

    Science.gov (United States)

    Dvořáčková, Helena; Mykajlo, Irina; Záhora, Jaroslav

    2016-04-01

    In our experiment we have used biochar. This material is the product of the pyrolysis that has shown a positive effect on numerous physical and chemical soil properties. However, its influence on the biological component of the soil is very variable. A number of toxic substances that inhibit the soil productivity may be produced during pyrolysis process. The experiment dealt with the hypothesis concerning biochar toxicity reduction by simulating natural processes in the soil. Biochar has been exposed to aeration in the aquatic environment, enriched with nutrients and a source of native soil microflora. It has been created 6 variants in total, each with four replications. The soils samples have been placed in a phytotron for 90 days. Variants consisted of the soil with fertilizers adding (compost, biochar, activated biochar) and have been prepared as well as variants containing compost and biochar and activated biochar optionally. The highest aboveground biomass production has been estimated in variants containing compost, while the lowest production - in the variants containing conventional biochar. During production comparing of the variants with the conventional biochar, activated biochar and control samples it has been evident that activated biochar promotes plant growth, and in contradiction conventional biochar inhibits it. We will approach to the same conclusions when comparing variants with a combination of conventional biochar + compost and activated biochar + compost. Mineral nitrogen leaching has been another investigated parameter. The highest leaching has occurred in the control variant, while the lowest - in the variant with activated biochar (the leaching of nitrate nitrogen has been negligeable). Our results suggest that activated biochar has the potential; however, it is necessary to carry out similar experiments in the field conditions.

  13. Influence of pyrolysis temperature on composted sewage sludge biochar priming effect in a loamy soil.

    Science.gov (United States)

    Méndez, A; Tarquis, A M; Saa-Requejo, A; Guerrero, F; Gascó, G

    2013-10-01

    Biochar is a carbon-rich solid product obtained by the pyrolysis of organic materials. The carbon stability of biochar allows that it can be applied to soil for long-term carbon storage. This carbon stability is greatly influenced by the pyrolysis temperature and the raw material used for biochar production. The aim of the present work is to study the soil carbon sequestration after the application of biochar from sewage sludge (SL) pyrolysis at two different temperatures (400 and 600 °C). For this purpose, soil CO2 emissions were measured for 80 d in an incubation experiment after soil amendment with the SL and each biochar at a dosage of 8 wt%. Biochar reduced the CO2 emissions during incubation between 11% and 32% relative to the SL treatment. The CO2 data were fit to a dual exponential model, and the CO2 emissions were simulated at different times (1, 5 and 10 yr). Additionally, the kinetics of the CO2 evolution from SL, two biochar samples, soil and amended soil were well fit to a dual first-order kinetic model with correlation coefficients greater than 0.93. The simulation of CO2 emissions from the soil by applying the proposed double first-order kinetic model (kg CO2-C ha(-1)) showed a reduction of CO2 emissions between 301 and 932 kg CO2-C ha(-1)with respect to the direct application of raw sewage sludge after 10 yr. Copyright © 2013 Elsevier Ltd. All rights reserved.

  14. Biochar Properties Influencing Greenhouse Gas Emissions in Tropical Soils Differing in Texture and Mineralogy.

    Science.gov (United States)

    Butnan, Somchai; Deenik, Jonathan L; Toomsan, Banyong; Antal, Michael J; Vityakon, Patma

    2016-09-01

    The ability of biochar applications to alter greenhouse gases (GHGs) (CO, CH, and NO) has been attracting research interest. However, inconsistent published results necessitate further exploration of potential influencing factors, including biochar properties, biochar rates, soil textures and mineralogy, and their interactions. Two short-term laboratory incubations were conducted to evaluate the effects of different biochars: a biochar with low ash (2.4%) and high-volatile matter (VM) (35.8%) contents produced under low-temperature (350°C) traditional kiln and a biochar with high ash (3.9%) and low-VM (14.7%) contents produced with a high-temperature (800°C) Flash Carbonization reactor and different biochar rates (0, 2, and 4% w/w) on the GHG emissions in a loamy-sand Ultisol and a silty-clay-loam Oxisol. In the coarse-textured, low-buffer Ultisol, cumulative CO and CH emissions increased with increasing VM content of biochars; however, CO emission sharply decreased at 83 μg VM g soil. In the fine-textured, high-buffer Oxisol, there were significant positive effects of VM content on cumulative CO emission without suppression effects. Regarding cumulative NO emission, there were significant positive effects in the Mn-rich Oxisol. Ash-induced increases in soil pH had negative effects on all studied GHG emissions. Possible mechanisms include the roles biochar VM played as microbial substrates, a source of toxic compounds and complexing agents reducing the toxicity of soil aluminum and manganese, and the role of biochar ash in increasing soil pH affecting GHG emissions in these two contrasting soils. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  15. The influence of soil resources and plant traits on invasion and restoration in a subtropical woodland

    Science.gov (United States)

    Yelenik, Stephanie G.; D'Antonio, Carla M.; August-Schmidt, Elizabeth

    2017-01-01

    It has been shown in some cases that nitrogen (N) addition to soil will increase abundance of plant invaders because many invaders have traits that promote rapid growth in response to high resource supply. Similarly, it has been suggested, and sometimes shown, that decreasing soil N via carbon (C) additions can facilitate native species recovery. Yet all species are unlikely to respond to resource supply in the same way. We asked how soil nutrients and competition affect native and exotic woody species in a restoration experiment where we added N or C, and crossed soil manipulation with the manipulation of dominant exotic grass abundance in a Hawaiian subtropical woodland. We related changes in survival and growth of outplanted individuals to native/exotic status and plant traits. As a group, N-fixers showed reduced survival compared to non-fixers in response to added N, with Morella faya (exotic) and Acacia koa (native) having dramatic negative responses. Among non-fixers, species with greater foliar %N had more positive survival responses to increasing soil N. Specific leaf area was not predictive of responses to nutrients or competition. In general, responses to carbon addition were weak, although reducing competition from existing exotic grasses was beneficial for all outplanted species, with N-fixers showing the most positive response. We conclude that commonly used restoration strategies to clear exotic species or lower soil resources with C addition will most greatly benefit N-fixing species, which themselves may be unwanted invaders. Thus statements about the influence of increased soil N on invasions should be carefully dissected by considering the traits (such as N-fixation status) of the regional species pool.

  16. Influence of plants on the chemical extractability and biodegradability of 2,4-dichlorophenol in soil

    Energy Technology Data Exchange (ETDEWEB)

    Boucard, Tatiana K.; Bardgett, Richard D.; Jones, Kevin C.; Semple, Kirk

    2005-01-01

    This study investigated the fate and behaviour of [UL-{sup 14}C] 2,4-dichlorophenol (DCP) in planted (Lolium perenne L.) and unplanted soils over 57 days. Extractability of [UL-{sup 14}C] 2,4-DCP associated activity was measured using calcium chloride (CaCl{sub 2}), acetonitrile-water and dichloromethane (DCM) extractions. Biodegradability of [UL-{sup 14}C] 2,4-DCP associated activity was assessed through measurement of {sup 14}CO{sub 2} production by a degrader inoculum (Burkholderia sp.). Although extractability and mineralisation of [UL-{sup 14}C] 2,4-DCP associated activity decreased significantly in both planted and unplanted soils, plants appeared to enhance the sequestration process. After 57 days, in unplanted soil, 27% of the remaining [UL-{sup 14}C] 2,4-DCP associated activity was mineralised by Burkholderia sp., and 13%, 48%, and 38% of {sup 14}C-activity were extracted by CaCl{sub 2}, acetonitrile-water and DCM, respectively. However, after 57 days, in planted soils, only 10% of the [UL-{sup 14}C] 2,4-DCP associated activity was available for mineralisation, whilst extractability was reduced to 2% by CaCl{sub 2}, 17% by acetonitrile-water and 11% by DCM. This may be due to the effect of plants on soil moisture conditions, which leads to modification of the soil structure and trapping of the compound. However, the influence of plants on soil biological and chemical properties may also play a role in the ageing process.

  17. Influence of transport infrastructure on water permeability of soils of Western Siberia

    Science.gov (United States)

    Eremin, Dmitry; Eremina, Diana

    2017-10-01

    Correctly designed transport infrastructure should support the current economic relations. It should provide a reserve for development of economy of the region in the future. In Western Siberia, new highways are actively being built and major repairs of the operating roads are being conducted. Local materials are often used in the roadbed construction. In the Tyumen region, it is usually sandy silt and clayey sand. The soil has unfavourable physico-mechanical properties. The soil is prone to water and wind erosion. This type of ground gets on the adjacent to the road territory. Studies on the influence of highways on soil permeability were carried out on the basis of the federal highway Tyumen-Omsk. Three types of soils, which are actively used in the agricultural sector, were considered. It is found that the content of particles with the size less than 0.01 mm reaches 32% in the soil used in road construction. It is noted that a part of these particles accumulates on the adjacent to the road territory since it is being washed out from roadbed. The content of physical clay (natural hydrological drain, results in the territory bogging. An inverse close correlation was established between the content of physical clay (<0.01 mm) and water permeability (r = 0.90).

  18. [Influence of tobacco-Chuanminshen violaceum rotation on microbe community in soil].

    Science.gov (United States)

    Zhang, Dong-Yan; Zhao, Jian; Yang, Shui-Ping; Mo, Jing-Jing; He, Da-Min; Wang, Jun; Gou, Jian-Yu; Zhang, Xue; Jiang, Wei; Wen, Ming-Xia

    2016-12-01

    Soil microbes are the important indicator of soil quality. For exploring Chuanminshen violaceum planting to microbial effects in tobacco soil, this paper adopted Illumina MiSeq high-throughput sequencing to research the change of bacteria and fungi at the phylum and genus in the soil. The results showed that the Ch. violaceum planting increased the biodiversity of bacteria and fungi. The influence on fungi was greater than that on bacteria. It greatly increased the sequence of fungi, it obtained 32 978 16S rDNA and 32 229 18S rDNA sequence number. There was no change of the top three phylums in bacteria, but the content changed, Proteobacteria and Acidobacteria reduced by 1.73% and 1.4% respectively, and Actinobacteria increased by 0.65%. The advantage phylum Ascomycete in tobacco reduced by 27.99% to be second advantage phylum after Ch. violaceum planting, and the second advantage phylum Basidiomycete increased by 23.69% to become the first dominant fungi. At the genus, Ch. violaceum planting changed the order of dominant genus and the abundance was also changed. Some changed largely such as uncultured Acidobacteriaceae Subgroup-1, Gemmatimonas, Subgroup-2,uncultured Nitrosomonadaceae for bacteria, norank Sordariales, norank Agaricomycetes, Phialophora for fungi. Especially the rotation increased antagonistic microbes and physiological microbes and decreased pathogenic microbes. So the Ch. violaceum planting can improve the microbe community in tobacco soil. Copyright© by the Chinese Pharmaceutical Association.

  19. Influence of hydrological regime on pore water metal concentrations in a contaminated sediment-derived soil

    Energy Technology Data Exchange (ETDEWEB)

    Du Laing, G. [Laboratory of Analytical Chemistry and Applied Ecochemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Gent 9000 (Belgium)]. E-mail: gijs.dulaing@ugent.be; Vanthuyne, D.R.J. [Laboratory of Analytical Chemistry and Applied Ecochemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Gent 9000 (Belgium); Vandecasteele, B. [Institute for Agricultural and Fisheries Research, Plant Unit, Burg. van Gansberghelaan 109, Box 1, Merelbeke 9820 (Belgium); Tack, F.M.G. [Laboratory of Analytical Chemistry and Applied Ecochemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Gent 9000 (Belgium); Verloo, M.G. [Laboratory of Analytical Chemistry and Applied Ecochemistry, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, Gent 9000 (Belgium)

    2007-06-15

    Options for wetland creation or restoration might be limited because of the presence of contaminants in the soil. The influence of hydrological management on the pore water concentrations of Cd, Cr, Cu, Fe, Mn, Ni and Zn in the upper soil layer of a contaminated overbank sedimentation zone was investigated in a greenhouse experiment. Flooding conditions led to increased Fe, Mn, Ni and Cr concentrations and decreased Cd, Cu and Zn concentrations in the pore water of the upper soil layer. Keeping the soil at field capacity resulted in a low pore water concentration of Fe, Mn and Ni while the Cd, Cu, Cr and Zn concentrations increased. Alternating hydrological conditions caused metal concentrations in the pore water to fluctuate. Formation and re-oxidation of small amounts of sulphides appeared dominant in determining the mobility of Cd, Cu, and to a lesser extent Zn, while Ni behaviour was consistent with Fe/Mn oxidation and reduction. These effects were strongly dependent on the duration of the flooded periods. The shorter the flooded periods, the better the metal concentrations could be linked to the mobility of Ca in the pore water, which is attributed to a fluctuating CO{sub 2} pressure. - The hydrological regime is a key factor in determining the metal concentration in the pore water of a contaminated sediment-derived soil.

  20. Influences of humic acid and fulvic acid on horizontal leaching behavior of anthracene in soil barriers.

    Science.gov (United States)

    Yu, Sheng; Li, Bang-Yu; Chen, Yi-Hu

    2015-12-01

    The influences of humic acid (HA) and fulvic acid (FA) on horizontal leaching behaviors of anthracene in barriers were investigated. Soil colloids (≤1 μm) were of concern because of their abilities of colloid-facilitated transport for hydrophobic organic compounds with soluble and insoluble organic matters. Through freely out of the barriers in the presence of soil colloids with FA added, the higher concentrations of anthracene were from 320 μg L(-1) (D1 and D3) to 390 μg L(-1) (D2 and D4) with 1 to 20 cm in length. The contents of anthracene were distributed evenly at 25 ng g(-1) dry weight (DW) (D1 and D3) and 11 ng g(-1) DW (D2 and D4) in barriers. Therefore, anthracene leaching behaviors were mainly induced by soil colloids with soluble organic matters. The insoluble organic matters would facilitate anthracene onto soil colloids and enhance the movement in and through porous media of soil matrix.

  1. Influence of wood-derived biochar on the compactibility and strength of silt loam soil

    Science.gov (United States)

    Ahmed, Ahmed; Gariepy, Yvan; Raghavan, Vijaya

    2017-04-01

    Biochar is proven to enhance soil fertility and increase crop productivity. Given that the influence of biochar on soil compaction remains unclear, selected physico-mechanical properties of soil amended with wood-derived biochar were assessed. For unamended silt loam, the bulk density, maximum bulk density, optimum moisture content, plastic limit, liquid limit, and plasticity index were 1.05 Mg m-3, 1.69 Mg m-3, 16.55, 17.1, 29.3, and 12.2%, respectively. The penetration resistance and shear strength of the unamended silt loam compacted in the standard compaction Proctor mold and at its optimum moisture content were 1800 kPa and 850 kPa, respectively. Results from amending the silt loam with 10% particle size ranges (0.5-212 μm) led to relative decreases of 18.1, 17.75, 66.66, and 97.4% in bulk density, maximum bulk density, penetration resistance, and shear strength, respectively; a 26.8% relative increase in optimum moisture content; along with absolute increases in plastic limit, liquid limit, and plasticity index of 5.3, 13.7, and 8.4%, respectively. While the biochar-amended silt loam soil was more susceptible to compaction, however, soil mechanical impedance enhanced.

  2. Emission of Carbon Dioxide Influenced by Different Water Levels from Soil Incubated Organic Residues

    Science.gov (United States)

    Hossain, M. B.; Puteh, A. B.

    2013-01-01

    We studied the influence of different organic residues and water levels on decomposition rate and carbon sequestration in soil. Organic residues (rice straw, rice root, cow dung, and poultry litter) including control were tested under moistened and flooding systems. An experiment was laid out as a complete randomized design at 25°C for 120 days. Higher CO2-C (265.45 mg) emission was observed in moistened condition than in flooding condition from 7 to 120 days. Among the organic residues, poultry litter produced the highest CO2-C emission. Poultry litter with soil mixture increased 121% cumulative CO2-C compared to control. On average, about 38% of added poultry litter C was mineralized to CO2-C. Maximum CO2-C was found in 7 days after incubation and thereafter CO2-C emission was decreased with the increase of time. Control produced the lowest CO2-C (158.23 mg). Poultry litter produced maximum cumulative CO2-C (349.91 mg). Maximum organic carbon was obtained in cow dung which followed by other organic residues. Organic residues along with flooding condition decreased cumulative CO2-C, k value and increased organic C in soil. Maximum k value was found in poultry litter and control. Incorpored rice straw increased organic carbon and decreased k value (0.003 g d−1) in soil. In conclusion, rice straw and poultry litter were suitable for improving soil carbon. PMID:24163626

  3. Environmental factors influencing soil testate amoebae in herbaceous and shrubby vegetation along an altitudinal gradient in subarctic tundra (Abisko, Sweden).

    Science.gov (United States)

    Tsyganov, Andrey N; Milbau, Ann; Beyens, Louis

    2013-05-01

    Shifts in community composition of soil protozoa in response to climate change may substantially influence microbial activity and thereby decomposition processes. However, effects of climate and vegetation on soil protozoa remain poorly understood. We studied the distribution of soil testate amoebae in herbaceous and shrubby vegetation along an altitudinal gradient (from below the treeline at 500 m to the mid-alpine region at 900 m a.s.l.) in subarctic tundra. To explain patterns in abundance, species diversity and assemblage composition of testate amoebae, a data set of microclimate and soil chemical characteristics was collected. Both elevation and vegetation influenced the assemblage composition of testate amoebae. The variation was regulated by interactive effects of summer soil moisture, winter soil temperature, soil pH and nitrate ion concentrations. Besides, soil moisture regulated non-linear patterns in species richness across the gradient. This is the first study showing the effects of winter soil temperatures on species composition of soil protozoa. The effects could be explained by specific adaptations of testate amoebae such as frost-resistant cysts allowing them to survive low winter temperatures. We conclude that the microclimate and soil chemical characteristics are the main drivers of changes in protozoan assemblage composition in response to elevation and vegetation. Copyright © 2012 Elsevier GmbH. All rights reserved.

  4. The influences of selected soil properties on Pb availability and its transfer to wheat (Triticum aestivum L.) in a polluted calcareous soil.

    Science.gov (United States)

    Safari, Yaser; Delavar, Mohammad-Amir; Zhang, Chaosheng; Esfandiarpour-Boroujeni, Isa; Owliaie, Hamid-Reza

    2015-12-01

    Accumulated anthropogenic heavy metals in the surface layer of agricultural soils may be transferred through the food chain via plant uptake processes. The objectives of this study were to assess the spatial distribution of lead (Pb) in the soils and wheat plants and to determine the soil properties which may affect the Pb transferring from soil to wheat plants in Zanjan Zinc Town area, northwestern Iran. A total of 110 topsoil samples (0-20 cm) were systematically collected from an agricultural area near a large metallurgical factory for the analyses of physico-chemical properties and total and bioavailable Pb concentrations. Furthermore, a total of 65 wheat samples collected at the same soil sampling locations were analyzed for Pb concentration in different plant parts. The results showed that elevated Pb concentrations were mostly found in soils located surrounding the industrial source of pollution. The bioavailable Pb concentration in the studied soils was up to 128.4 mg kg(-1), which was relatively high considering the observed soil alkalinity. 24.6% of the wheat grain samples exceeded the FAO/WHO maximum permitted concentration of Pb in wheat grain (0.2 mg kg(-1)). Correlation analyses revealed that soil organic matter, soil pH, and clay content showed insignificant correlation with Pb concentration in the soil and wheat grains, whereas calcium carbonate content showed significantly negative correlations with both total and bioavailable Pb in the soil, and Pb content in wheat grains, demonstrating the strong influences of calcium carbonate on Pb bioavailability in the polluted calcareous soils.

  5. Influence of different fertilization on the dissolved organic carbon, nitrogen and phosphorus accumulation in acid and limed soils

    Directory of Open Access Journals (Sweden)

    Ieva Jokubauskaite

    2015-04-01

    Full Text Available Soil quality has become an important issue in soil science. Dissolved organic carbon (DOC is believed to play an important role in soil processes and in the C, N and P balances, their supplies to plants in all types of soils. It is much more sensitive to soil management than is soil organic matter as a whole, and can be used as a key indicator of soil natural functions. This study aimed to assess the influence of different organic fertilizers on DOC and N, P accumulation. The study was carried out on a moraine loam soil at the Vezaiciai Branch of Lithuanian Research Centre for Agriculture and Forestry in 2012. Farmyard manure (FYM (60 t ha -1 and alternative organic fertilizers (wheat straw, rape residues, roots, stubble, perennial grasses were applied on two soil backgrounds - acid and limed. DOC was analysed using an ion chromatograph SKALAR. Application of organic amendments resulted in a significant increase of soil organic carbon (SOC content, which demonstrates a positive role of organic fertilizers in SOC conservation. The combination of different organic fertilizers and liming had a significant positive effect on DOC concentration in the soil. The highest DOC content (0.241 g kg-1 was established in the limed soil fertilized with farmyard manure. The most unfavourable status of DOC was determined in the unlimed, unfertilized soil. The limed and FYM-applied soil had the highest nitrogen (1.47 g kg-1 and phosphorus (0.84 g kg-1 content compared to the other treatments. Organic fertilizers gave a significant positive effect on SOC and DOC content increase in the topsoil. This immediate increase is generally attributed to the presence of soluble materials in the amendments. Application of organic fertilizers in acid and limed soil increased the nutrient stocks and ensured soil chemical indicators at the optimal level for plant growth and thus may provide a mechanism as well as prediction opportunities for soil fertility, conservation

  6. Ubiquitous net volatilization of polycyclic aromatic hydrocarbons from soils and parameters influencing their soil-air partitioning.

    Science.gov (United States)

    Cabrerizo, Ana; Dachs, Jordi; Moeckel, Claudia; Ojeda, María-José; Caballero, Gemma; Barceló, Damià; Jones, Kevin C

    2011-06-01

    Soils are a major reservoir of organic pollutants, and soil-air partitioning and exchange are key processes controlling the regional fate of pollutants. Here, we report and discuss the soil concentrations of polycyclic aromatic hydrocarbons (PAHs), their soil fugacities, the soil-air partition coefficients (K(SA)) and soil-air gradients for rural and semirural soils, in background areas of N-NE Spain and N-NW England. Different sampling campaigns were carried out to assess seasonal variability and differences between sampling sites. K(SA) values were dependent on soil temperature and soil organic quantity and type. Soil fugacities of phenanthrene and its alkyl homologues were 1-2 orders of magnitude higher than their ambient air fugacities for all sampling sites and periods. The soil to air fugacity ratio was correlated with soil temperature and soil redox potential. Similar trends for other PAHs were found but with lower fugacity ratios. The ubiquitous source of PAHs from background soils to the atmosphere found in all temperate regions in different seasons provides an indirect evidence of potential in situ generation of two to four ring PAHs and their alkyl homologues in the surface soil. We discuss this hypothetical biogenic source and other potential processes that could drive the high soil to air fugacity ratios of some PAHs.

  7. Influence of plant roots on electrical resistivity measurements of cultivated soil columns

    Science.gov (United States)

    Maloteau, Sophie; Blanchy, Guillaume; Javaux, Mathieu; Garré, Sarah

    2016-04-01

    Electrical resistivity methods have been widely used for the last 40 years in many fields: groundwater investigation, soil and water pollution, engineering application for subsurface surveys, etc. Many factors can influence the electrical resistivity of a media, and thus influence the ERT measurements. Among those factors, it is known that plant roots affect bulk electrical resistivity. However, this impact is not yet well understood. The goals of this experiment are to quantify the effect of plant roots on electrical resistivity of the soil subsurface and to map a plant roots system in space and time with ERT technique in a soil column. For this research, it is assumed that roots system affect the electrical properties of the rhizosphere. Indeed the root activity (by transporting ions, releasing exudates, changing the soil structure,…) will modify the rhizosphere electrical conductivity (Lobet G. et al, 2013). This experiment is included in a bigger research project about the influence of roots system on geophysics measurements. Measurements are made on cylinders of 45 cm high and a diameter of 20 cm, filled with saturated loam on which seeds of Brachypodium distachyon (L.) Beauv. are sowed. Columns are equipped with electrodes, TDR probes and temperature sensors. Experiments are conducted at Gembloux Agro-Bio Tech, in a growing chamber with controlled conditions: temperature of the air is fixed to 20° C, photoperiod is equal to 14 hours, photosynthetically active radiation is equal to 200 μmol m-2s-1, and air relative humidity is fixed to 80 %. Columns are fully saturated the first day of the measurements duration then no more irrigation is done till the end of the experiment. The poster will report the first results analysis of the electrical resistivity distribution in the soil columns through space and time. These results will be discussed according to the plant development and other controlled factors. Water content of the soil will also be detailed

  8. Soil influence on Carignane wine quality in the AOC Priorat, Northeast Spain

    Science.gov (United States)

    Nadal, Montserrat; Sanchez Ortiz, Antoni; Biel, Carme

    2014-05-01

    The impact of global warming obviously varies according to the type of wine produced and the geographical location. The importance of understanding climate variability and soil water holding capacity is especially important in vineyards growing in steep slopes. Texture and soil depth are factors that influence the accumulation of water and, therefore, its influence on grapes ripening. The study was carried out during 2009 and 2010 vintages in two regions El Molar (EM) and Porrera (PO). 5 different parcels located in the AOC Priorat, selected by having different soil texture, facing slope orientation and altitude: EMDA, EMBA, POMO, POME and PODA. Weather stations located in each vineyard recorded climate data (temperature, humidity, rainfall, radiation, wind speed and direction). Tukey test was applied for post-hocanalysis (SPSS statistical package, version 17.0) between plots. Climatic data revealed 2009 as a warmer vintage comparing with the temperate 2010. Porrera region resulted in lower Temperature, VPD and GDD. Soil analysis revealed EMDA as a parcel having the finest texture. In Porrera the highest and steepest vineyard (PODA) show the higher amount of gravels and stones; whilst POMO has a balance between fine elements and stones. Topsoil and subsoil layers are notably different in the POME parcel. The two plots PODA and EMDA are those with major differences between berry weights within the two years of study, indicating a greater variability. EMDA has the largest grape production, regardless of the vintage probably due to the fine soil texture. At the end of the maturation period, the ratio SFT / kg was higher in EMDA and PODA, corresponding with a greater leaf area in EMDA. In general the two plots are more irregular, with greater differences over the years with higher rainfall (2010) compared to dry years (2009), where the ratios do not show much difference. Concerning Ravaz-Index, the most unbalanced vigour corresponds to EMDA (this explains major

  9. The Influence of Rotation, Tillage and Row Spacing on Near-Surface Soil Temperature for Winter Wheat in Southern Alberta

    Energy Technology Data Exchange (ETDEWEB)

    Larney, F. J.; Ren, Tennis L.; McGinn, Sean M.; Lindwall, C W.; Izaurralde, R Cesar C.

    2003-02-01

    The influence of rotation, tillage and row spacing on near-surface soil temperature for winter wheat in southern Alberta. Rotation, tillage and row spacing and their effects on surface residue levels can modify soil temperature. Our study investigated the effect of rotation, tillage and row spacing on near-surface (0.025 m) soil temperature under winter wheat (Triticum aestivum L.) in 1993-94 and 1994-95.

  10. Diversity and Abundance of Soil Animals as Influenced by Long-Term Fertilization in Grey Desert Soil, China

    OpenAIRE

    Maibo Jiang; Xihe Wang; Yunhao Liusui; Xueqing Sun; Chengyi Zhao; Hua Liu

    2015-01-01

    The relationship between soil fauna and different fertilizer management practices is of growing concern. The aim of this research was to investigate the response of soil fauna to fertilization regimes, to explore the relationships among the community of soil animals, soil moisture and crop yields. The application of organic fertilizers (i.e., sheep manure or crop residues) increased crop yields and promoted the number of individuals and species of soil fauna owing to the exogenous organic mat...

  11. [Multi-scale correlation analysis of soil organic carbon with its influence factors using wavelet transform].

    Science.gov (United States)

    Jiang, Chun; Qian, Le-Xiang; Wu, Zhi-Feng; Wen, Ya; Deng, Nan-Rong

    2013-12-01

    Based on GIS, this paper chose the soil organic carbon (SOC) density in soil surface layer (0-20 cm) and its influence factors (NDVI, elevation, slope and aspect) as research objects, one-dimensional discrete wavelet transform (DWT) was used as the multi-scale decomposition tool to quantitatively revealed the multi-scale correlation relationships among SOC density and its influence factors on the grid scale along 4 transects of the mountainous area of Guangdong Province. The results showed that the correlation among SOC density and its influence factors was scale-dependent with varying degree. The influence of NDVI was strongest at the scales of 2, 8 and 16 km, while elevation showed its greatest influence at the scales of 8 and 16 km. The control action of slope was rather weak, with a less significant correlation depending on scale. The negative effect of aspect became stronger with increasing scale at > 2 km scale. The SOC density of the different transects was affected by various factors, of which NDVI and elevation were the main factors, and slope and aspect only reacted with individual transects at larger scales.

  12. Influence of soil parameters on the linearity of the soil-to-plant transfer process of {sup 238}U and {sup 226}Ra

    Energy Technology Data Exchange (ETDEWEB)

    Blanco Rodriguez, P.; Vera Tome, F. [Natural Radioactivity Group. Universidad de Extremadura, 06071 Badajoz (Spain); Lozano, J.C. [Laboratorio de Radiactividad Ambiental. Universidad de Salamanca, 37008 Salamanca (Spain)

    2014-07-01

    Transfer from soil to plant is an important input of radionuclides into the food chain. Also, the mobility of radionuclides in soils is enhanced through their passage into the plant compartment. Thus, the soil-to-plant transfer of radionuclides raises the potential human dose. In radiological risk assessment models, this process is usually considered to be an equilibrium process such that the activity concentration in plants is linearly related to the soil concentration through a constant transfer factor (TF). However, the large variability present by measured TF values leads to major uncertainties in the assessment of risks. One possible way to reduce this variability in TF values is to parametrize their determination. This paper presents correlations of TF with the major element concentrations in soils. The findings confirm the major influence of the chemical environment of a soil on the assimilation process. The variability of TF might be greatly reduced if only the labile fraction were considered. Experiments performed with plants (Helianthus annuus L.) growing in a hydroponic medium appear to confirm this suggestion, showing a linear correlation between the plant and the soil solution activity concentrations. Extracting the labile fraction of a real soil is no trivial task, however. A possible operationally definable method is to consider the water-soluble together with the exchangeable fractions of the soil. Studies performed in granitic soils showed that the labile concentration of uranium and radium strongly depended on the soil's textural characteristics. In this sense, a parametrization is proposed of the labile uranium and radium concentration as a function of the soil's granulometric parameters. (authors)

  13. Juvenile Southern Pine Response to Fertilization Is Influenced by Soil Drainage and Texture

    Directory of Open Access Journals (Sweden)

    Timothy J. Albaugh

    2015-08-01

    Full Text Available We examined three hypotheses in a nutrient dose and application frequency study installed in juvenile (aged 2–6 years old Pinus stands at 22 sites in the southeastern United States. At each site, eight or nine treatments were installed where nitrogen was applied at different rates (0, 67, 134, 268 kg ha−1 and frequencies (0, 1, 2, 4 and 6 years in two or four replications. Phosphorus was applied at 0.1 times the nitrogen rate and other elements were added as needed based on foliar nutrient analysis to insure that nutrient imbalances were not induced with treatment. Eight years after treatment initiation, the site responses were grouped based on texture and drainage characteristics: soil group 1 consisted of poorly drained soils with a clayey subsoil, group 2 consisted of poorly to excessively drained spodic soils or soils without a clay subsoil, and group 3 consisted of well-drained soils with a clayey subsoil. We accepted the first hypothesis that site would be a significant factor explaining growth responses. Soil group was also a significant factor explaining growth response. We accepted our second hypothesis that the volume growth-cumulative dose response function was not linear. Volume growth reached an asymptote in soil groups 1 and 3 between cumulative nitrogen doses of 300–400 kg ha−1. Volume growth responses continued to increase up to 800 kg ha−1 of cumulatively applied nitrogen for soil group 2. We accepted our third hypothesis that application rate and frequency did not influence the growth response when the cumulative nitrogen dose was equivalent. There was no difference in the growth response for comparisons where a cumulative nitrogen dose of 568 kg ha−1 was applied as 134 kg ha−1 every two years or as 269 kg ha−1 every four years, or where 269 kg ha−1 of nitrogen was applied as four applications of 67 kg ha−1 every two years or as two applications of 134 kg ha−1 every four years. Clearly, the sites examined

  14. Acidification processes and soil leaching influenced by agricultural practices revealed by strontium isotopic ratios

    Science.gov (United States)

    Pierson-Wickmann, Anne-Catherine; Aquilina, Luc; Weyer, Christina; Molénat, Jérôme; Lischeid, Gunnar

    2009-08-01

    In natural river systems, the chemical and isotopic composition of stream- and ground waters are mainly controlled by the geology and water-rock interactions. The leaching of major cations from soils has been recognized as a possible consequence of acidic deposition from atmosphere for over 30 years. Moreover, in agricultural areas, the application of physiological acid fertilizers and nitrogen fertilizers in the ammonia form may enhance the cation leaching through the soil profile into ground- and surface waters. This origin of leached cations has been studied on two small and adjacent agricultural catchments in Brittany, western France. The study catchments are drained by two first-order streams, and mainly covered with cambisoils, issued from the alteration and weathering of a granodiorite basement. Precipitations, soil water- and NH 4 acetate-leachates, separated minerals, and stream waters have been investigated. Chemical element ratios, such as Ba/Sr, Na/Sr and Ca/Sr ratios, as well as Sr isotopic ratios are used to constrain the relative contribution from potential sources of stream water elements. Based on Sr isotopic ratio and element concentration, soil water- and NH 4 acetate leaching indicates (1) a dominant manure/slurry contribution in the top soil, representing a cation concentrated pool, with low 87Sr/ 86Sr ratios; (2) in subsoils, mineral dissolution is enhanced by fertilizer application, becoming the unique source of cations in the saprolite. The relatively high weathering rates encountered implies significant sources of cations which are not accessory minerals, but rather plagioclase and biotite dissolution. Stream water has a very different isotopic and chemical composition compared to soil water leaching suggesting that stream water chemistry is dominated by elements issued from mineral and rock weathering. Agriculture, by applications of chemical and organic fertilizers, can influence the export of major base cations, such as Na +. Plagioclase

  15. INFLUENCES OF SOIL AND GENOTYPES ON MICRONUTRIENTS STATUS IN MAIZE PLANTS

    Directory of Open Access Journals (Sweden)

    Manda Antunović

    2003-06-01

    Full Text Available Ten corn hybrids were grown on two soil types of Drava Valley in Slatina area (alluvial soil and pseudogley during two growing seasons (1998 and 1999. The ear-leaf at the beginning of silking stage was taken for chemical analysis. Micronutrient concentrations in corn leave samples were measured by ICP-AES after their microwave digestion using concentrated HNO3+H2O2. Mobile fraction of these elements in soils was also determined by ICP-AES after their extraction by ammonium acetate-EDTA. In both year of the testing, corn yields on acid soil were about 25% lower in comparison with alluvial soil. Mean concentrations of tested elements in corn leaves found in our investigations (mg kg-1 were 30.4 (Zn, 129.4 (Mn and 190.0 (Fe, respectively. In general, significant influences of growing season, soil type and genotype on Zn, Mn and Fe status in corn were found. For example, in the first year of testing higher Zn and Mn were found, as well as lower Fe concentrations in comparison with the second year. Corn growing on alluvial soil occurred due to lower Zn and Mn as well as higher Fe concentrations in plants compared to growing on pseudogley. However, these findings are not in coincidence with status of mobile fractions of Zn and Mn in the experimental plots. We presume that pH value near to neutral on alluvial soil could be responsible factor because low availability of Zn and Mn for plants occured under these conditions. An important role of heredity factors on Zn, Mn and Fe status in corn was found in our study because differences among the hybrids (mean values for two growing seasons and two soil types under identical environmental conditions were in ranges (mg kg-1 from 26.8 to 36.0 (Zn, from 98.6 to 150.4 (Mn and from 168.2 to 222.4 (Fe, respectively. It is very indicative that the first-ranged hybrid concerning grain yield (OsSK458exp: 12.34 t ha-1 is in the group characterizing low concentrations of Zn, Mn and Fe in leaves.

  16. Spatially explicit analysis of metal transfer to biota: influence of soil contamination and landscape.

    Directory of Open Access Journals (Sweden)

    Clémentine Fritsch

    Full Text Available Concepts and developments for a new field in ecotoxicology, referred to as "landscape ecotoxicology," were proposed in the 1990s; however, to date, few studies have been developed in this emergent field. In fact, there is a strong interest in developing this area, both for renewing the concepts and tools used in ecotoxicology as well as for responding to practical issues, such as risk assessment. The aim of this study was to investigate the spatial heterogeneity of metal bioaccumulation in animals in order to identify the role of spatially explicit factors, such as landscape as well as total and extractable metal concentrations in soils. Over a smelter-impacted area, we studied the accumulation of trace metals (TMs: Cd, Pb and Zn in invertebrates (the grove snail Cepaea sp and the glass snail Oxychilus draparnaudi and vertebrates (the bank vole Myodes glareolus and the greater white-toothed shrew Crocidura russula. Total and CaCl(2-extractable concentrations of TMs were measured in soils from woody patches where the animals were captured. TM concentrations in animals exhibited a high spatial heterogeneity. They increased with soil pollution and were better explained by total rather than CaCl(2-extractable TM concentrations, except in Cepaea sp. TM levels in animals and their variations along the pollution gradient were modulated by the landscape, and this influence was species and metal specific. Median soil metal concentrations (predicted by universal kriging were calculated in buffers of increasing size and were related to bioaccumulation. The spatial scale at which TM concentrations in animals and soils showed the strongest correlations varied between metals, species and landscapes. The potential underlying mechanisms of landscape influence (community functioning, behaviour, etc. are discussed. Present results highlight the need for the further development of landscape ecotoxicology and multi-scale approaches, which would enhance our

  17. Plant species richness, identity and productivity differentially influence key groups of microbes in grassland soils of contrasting fertility.

    NARCIS (Netherlands)

    Deyn, de G.B.; Quirk, H.; Bardgett, R.D.

    2011-01-01

    The abundance of microbes in soil is thought to be strongly influenced by plant productivity rather than by plant species richness per se. However, whether this holds true for different microbial groups and under different soil conditions is unresolved. We tested how plant species richness, identity

  18. Plant species richness, identity and productivity differentially influence key groups of microbes in grassland soils of contrasting fertility

    NARCIS (Netherlands)

    De Deyn, G.B.; Quirk, H.; Bardgett, R.D.

    2011-01-01

    The abundance of microbes in soil is thought to be strongly influenced by plant productivity rather than by plant species richness per se. However, whether this holds true for different microbial groups and under different soil conditions is unresolved. We tested how plant species richness, identity

  19. Decadal-scale changes in forest soil carbon and nitrogen storage are influenced by organic matter removal during timber harvest

    Science.gov (United States)

    Ryan M. Mushinski; Thomas W. Boutton; D. Andrew Scott

    2017-01-01

    This study investigates whether different intensities of organic matter removal associated with timber harvest influence decadal-scale storage of soil organic carbon (SOC) and total nitrogen (TN) in the top 1 m of mineral soil 18 years postharvest in a Pinus taeda L. forest in the Gulf Coastal Plain. We quantified forest harvest-related changes in...

  20. Impacts of land use conversion on soil properties and soil erodibility.

    Science.gov (United States)

    Korkanc, Selma Yasar; Ozyuvaci, Necdet; Hizal, Ahmet

    2008-05-01

    Land use conversion can affect natural ecological processes such as surface runoff and erosion. Therefore, it has potential to change soil stability To investigate this process in depth, Iskalan creek catchment in the Black sea region, where excessive land use applications and erosion events have often occured, was selected as the study area. The objective was to determine the effects of land use conversion on soil properties, soil erodibility and the relationships among soil properties and some erodibility indices. Duplicate topsoil samples were taken by using steel cylinders at 100 different sampling points from three different land use types; 34 of them are in farmlands, 34 in rangelands and 32 in forestlands. Soil particle size distribution, loss of ignition, pH, electrical conductivity skeleton percentage and three erodibility indices were determined. Data were analysed by using Pearson correlation analysis (at 95% and 99% significance level), ANOVA and Tukey's test at 95 % significance level. According to study results, land use conversion affects some properties of soils significantly Loss of ignition of soils in forests was significantly higher than soils in farmlands and rangelands. Soil skeleton percentage in rangelands and farmlands were significantly different. The study results showed that there was significant difference between pH of soils in forests and farmlands (p properties such as clay and sand fraction of soils (p Topsoils of the study area were sensitive to erosion according to all three erodibility indices. The most sensitive soils were in farmlands.

  1. Cattle-rangeland management practices and perceptions of pastoralists towards rangeland degradation in the Borana zone of southern Ethiopia.

    Science.gov (United States)

    Solomon, T B; Snyman, H A; Smit, G N

    2007-03-01

    A survey was conducted in the Borana pastoral areas of southern Ethiopia to assess current livestock production systems, rangeland management practices and the perceptions of the pastoralists towards rangeland degradation. This information is considered vital to future pastoral development planning and interventions. Data were collected from a total of 20 villages that were identified from 5 peasant associations, namely Did Yabello, Moyatte, Did Harra, Dubuluk and Melbana. The average household size in the study area was 7.23. The majority of the pastoralists relied on both livestock and crop farming. The average livestock holding per household was 14 cattle, 10 goats, 6 sheep and 2 camels. Livestock holdings, with the exception of camels, has shown a declining trend over time. The two most important traditional rangeland management strategies adopted by the pastoralists included burning and mobility, but since 1974/75 burning has no longer been practised. With regard to mobility, the livestock herding falls in two categories, namely: home based and satellite herding. The former involves the herding of milking cows, calves and immature animals (2 years) further away from the encampments. Based on the pastoralists' perceptions, the major constraints on livestock production in descending order, were recurrent drought, feed and water scarcity, animal diseases, predators and communal land ownership. All the respondents considered the condition of the rangelands to have declined dramatically over time. In the past most development policies were based on equilibrium theories that opposed the communal use of the rangelands and traditional range management practices. The way in which the pastoral system affects the rangeland ecosystem functioning is contentious to this theory and the 'tragedy of the commons'. There was also a perceived problem of bush encroachment and the ban on traditional burning practices and recurrent droughts were seen as aggravating factors to this

  2. The influence of crop residues in vertical soil mobility of potassium

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    Osmar Rodrigues Brito

    2014-12-01

    Full Text Available This study has been developed to evaluate the influence of applying different types and doses of crop residues on potassium (K mobility in soil columns. Rhodic Haplustox samples were collected at depths of 0.0-0.10, 0.10-0.20 and 0.20-0.30 m and used to create such soil columns, keeping the same profile distribution. The experimental design was randomized with three replications and the treatments resulted in a 4x4 factorial design, 4 types of crop residues (brachiaria+sunflower; Mix (cultivated radish+oat+winter vetch; cultivated radish and wheat and 4 doses of residues (0, 10, 15, and 20 Mg ha-1. The grinded and dried residues were applied to the surface of the columns, which were then irrigated with distilled water and incubated for 10 days to stabilize the reactions. After incubation, the soil columns were disassembled and separated into 0.05 m layers (0.0-0.05, 0.05-0.10, 0.10-0.15, 0.15-0.20, 0.20-0.25 and 0.25-0.30 m. The samples of each layer were dried, sieved and analyzed to determine the amount of exchangeable K. The results obtained indicated that surface application of crop residues alters soil levels of exchangeable potassium, especially in the 0.0-0.05 m layer. Increases in residue doses may cause a significant and linear increase in exchangeable K content in the 0.0-0.05, 0.05-0.10 and 0.10-0.15 m soil layers. Superficial application of residues of cultivated radish and Mix produced the largest increases in levels of exchangeable K, reaching depths of 0.30 m. Increases in potassium adsorption in the soil surface layers reduces the need for potassium fertilization and can reduce production costs and environmental pollution.

  3. Influences of calcium availability and tree species on Ca isotope fractionation in soil and vegetation

    Science.gov (United States)

    Page, B.D.; Bullen, T.D.; Mitchell, M.J.

    2008-01-01

    The calcium (Ca) isotope system is potentially of great use for understanding biogeochemical processes at multiple scales in forest ecosystems, yet remains largely unexplored for this purpose. In order to further our understanding of Ca behavior in forests, we examined two nearly adjacent hardwood-dominated catchments with differing soil Ca concentrations, developed from crystalline bedrock, to determine the variability of 44Ca/ 40Ca ratios (expressed as ??44Ca) within soil and vegetation pools. For both sugar maple and American beech, the Ca isotope compositions of the measured roots and calculated bulk trees were considerably lighter than those of soil pools at these sites, suggesting that the trees were able to preferentially take up light Ca at the root-soil interface. The Ca isotope compositions of three of four root samples were among the lightest values yet reported for terrestrial materials (??44Ca ???-3.95???). Our results further indicate that Ca isotopes were fractionated along the transpiration streams of both tree species with roots having the least ??44Ca values and leaf litter the greatest. An approximately 2??? difference in ??44Ca values between roots and leaf litter of both tree species suggests a persistent fractionation mechanism along the transpiration stream, likely related to Ca binding in wood tissue coupled with internal ion exchange. Finally, our data indicate that differing tree species demand for Ca and soil Ca concentrations together may influence Ca isotope distribution within the trees. Inter-catchment differences in Ca isotope distributions in soils and trees were minor, indicating that the results of our study may have broad transferability to studies of forest ecosystems in catchments developed on crystalline substrates elsewhere. ?? 2008 Springer Science+Business Media B.V.

  4. Characterization and nutrient release from silicate rocks and influence on chemical changes in soil

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    Douglas Ramos Guelfi Silva

    2012-06-01

    Full Text Available The expansion of Brazilian agriculture has led to a heavy dependence on imported fertilizers to ensure the supply of the growing food demand. This fact has contributed to a growing interest in alternative nutrient sources, such as ground silicate rocks. It is necessary, however, to know the potential of nutrient release and changes these materials can cause in soils. The purpose of this study was to characterize six silicate rocks and evaluate their effects on the chemical properties of treated soil, assessed by chemical extractants after greenhouse incubation. The experimental design consisted of completely randomized plots, in a 3 x 6 factorial scheme, with four replications. The factors were potassium levels (0-control: without silicate rock application; 200; 400; 600 kg ha-1 of K2O, supplied as six silicate rock types (breccia, biotite schist, ultramafic rock, phlogopite schist and two types of mining waste. The chemical, physical and mineralogical properties of the alternative rock fertilizers were characterized. Treatments were applied to a dystrophic Red-Yellow Oxisol (Ferralsol, which was incubated for 100 days, at 70 % (w/w moisture in 3.7 kg/pots. The soil was evaluated for pH; calcium and magnesium were extracted with KCl 1 mol L-1; potassium, phosphorus and sodium by Mehlich 1; nickel, copper and zinc with DTPA; and the saturation of the cation exchange capacity was calculated for aluminum, calcium, magnesium, potassium, and sodium, and overall base saturation. The alternative fertilizers affected soil chemical properties. Ultramafic rock and Chapada mining byproduct (CMB were the silicate rocks that most influenced soil pH, while the mining byproduct (MB led to high K levels. Zinc availability was highest in the treatments with mining byproduct and Cu in soil fertilized with Chapada and mining byproduct.

  5. Removal of a mixture of pesticides by a Streptomyces consortium: Influence of different soil systems.

    Science.gov (United States)

    Fuentes, María S; Raimondo, Enzo E; Amoroso, María J; Benimeli, Claudia S

    2017-04-01

    Although the use of organochlorine pesticides (OPs) is restricted or banned in most countries, they continue posing environmental and health concerns, so it is imperative to develop methods for removing them from the environment. This work is aimed to investigate the simultaneous removal of three OPs (lindane, chlordane and methoxychlor) from diverse types of systems by employing a native Streptomyces consortium. In liquid systems, a satisfactory microbial growth was observed accompanied by removal of lindane (40.4%), methoxychlor (99.5%) and chlordane (99.8%). In sterile soil microcosms, the consortium was able to grow without significant differences in the different textured soils (clay silty loam, sandy and loam), both contaminated or not contaminated with the OPs-mixture. The Streptomyces consortium was able to remove all the OPs in sterile soil microcosm (removal order: clay silty loam > loam > sandy). So, clay silty loam soil (CSLS) was selected for next assays. In non-sterile CSLS microcosms, chlordane removal was only about 5%, nonetheless, higher rates was observed for lindane (11%) and methoxychlor (20%). In CSLS slurries, the consortium exhibited similar growth levels, in the presence of or in the absence of the OPs-mixture. Not all pesticides were removed in the same way; the order of pesticide dissipation was: methoxychlor (26%)>lindane (12.5%)>chlordane (10%). The outlines of microbial growth and pesticides removal provide information about using actinobacteria consortium as strategies for bioremediation of OPs-mixture in diverse soil systems. Texture of soils and assay conditions (sterility, slurry formulation) were determining factors influencing the removal of each pesticide of the mixture. Copyright © 2017 Elsevier Ltd. All rights reserved.

  6. The influence of defoamer on removal of PAHs in soil washing.

    Science.gov (United States)

    Shi, Zhentian; Chen, Jiajun

    2013-01-01

    The use of surfactants during soil washing process can create massive foam, which has a negative impact on the effective use of equipment. A series of tests was conducted to evaluate the defoaming performance of three defoamers and to investigate the influence on removal of polycyclic aromatic hydrocarbons (PAHs) during enhanced soil washing by the addition of the defoamer. Results showed that polydimethylsiloxane oil, which is the most common biomaterial used in commercial antifoaming and defoaming agents, has the best defoaming performance. With the addition of 0.1% polydimethylsiloxane oil, the removal ratios of total 16 PAHs (SigmaPAHs) increased up to 53.48% and 75.92% when washing time was 5 min and 30 min, respectively, compared with the removal ratios of 44.12% and 67.28% with Triton X-100 solution only. This indicated that the proper selection of defoamer not only solves massive foaming problem but also brings out a positive influence on PAH removal during the soil washing process. Three kinds of defoamers (kieselguhr, dodecanol, and polydimethylsiloxane oil) were collected to destroy the foam produced by Triton X-100. Among those defoamers, the polydimethylsiloxane (PDMS) oil has the best defoaming performances. The surface tension of the Triton X-100 solution with the addition of PDMS was lower. The addition of PDMS could improve the removal ratio of SigmaPAHs during soil washing. That may be attributed to the addition of the nonionic surfactant Tergitol NP-10 as the emulsifier in the defoamer. After all, the results do not provide any indication of the influence on the solubilization micelles. It is thus questionable whether other components of PDMS oil could improve the PAH solubilization.

  7. The role of soil biogeochemistry in wine taste: Soil factors influencing grape elemental composition, photosynthetic biomarkers and Cu/Zn isotopic signature of Vitis vinifera

    Science.gov (United States)

    Blotevogel, Simon; Oliva, Priscia; Darrozes, José; Viers, Jérôme; Audry, Stéphane; Courjault-Radé, Pierre; Orgogozo, Laurent; Le Guedard, Marina; Schreck, Eva

    2015-04-01

    Understanding the influence of soil composition in wine taste is of great economic and environmental interest in France and around the world. Nevertheless the impact of soil composition on wine taste is still controversially discussed. Since inorganic soil components do not have a proper taste and do not enter the plant anyway, their influence needs to be induced by nutrient absorption and its impact on plant functioning and grape composition. Indeed recent development of geological tracers of origin proof the existence of soil chemical and isotopic signatures in wine. However, type and scale of the impact of soil composition on wine taste are not well understood yet, and little experimental evidence exists due to the complexity of mechanisms involved. Thus, to provide evidence for the impact of soil composition on grape composition and potentially wine taste, we studied soil and plant material from two relevant vineyards (Soave, Italia). On those two directly adjacent vineyards, two different wines are produced with the same plant material and cultivation techniques. The vineyards only differ by their underlying bedrock - limestone versus basaltic rock - and thus present suitable conditions for investigating the impact of soil composition on grapes and wine. Pedological and mineralogical parameters were analyzed for the two vineyards whereas chemical extractions (citrate, CaCl2) were performed to determine nutrient bioavailability in both soils. Elemental compositions were determined by ICP-MS analyses in different compartments (soils, vine leaves and grapes). Isotopic fractionation of Cu and Zn was investigated in various samples as source tracers and in order to better understand fractionation mechanisms involved. Finally, plant health was studied using the Omega-3 biomarker which determines the fatty acid composition in vine leaves, directly involved in photosynthetic processes. Results show that the vineyards are characterized by two different soil types due

  8. Influence of Magnesium Perchlorate on the Pyrolysis of Organic Compounds in Martian Soil Analogs

    Science.gov (United States)

    Steininger, Harald; Goesmann, Fred

    2010-05-01

    Detection and identification of organic molecules derived from present or past life is the goal of the Martian Organic Molecule Analyser of the 2018 ExoMars mission of ESA. One part of the instrument is a pyrolysis gas chromatograph mass spectrometer pyr-GC-MS while the other is a laser desorption mass spectrometer. In the pyr-GC-MS a soil sample of app. 200 mg and then heated to a temperature of 900°C. [1] During this process the organic molecules desorb from the surface and are separated on the column of the GC and identified in the MS. The direct pyrolysis of soil samples without previous extraction is an uncommon way of sample preparation. In addition to the parameters of the pyrolysis of pure samples, for example temperatures and the soil composition influences the measurements in several ways. To evaluate the influence of the relative large surface of the soil on the pyrolysis and derivatization several tests have been conducted with simple organic molecules. The Phoenix mission discovered considerable amounts of magnesium perchlorate in the soil at the landing site. Perchlorates are oxidizing components and therefore might interact with the expected organics within the soil, especially if the soil is heated within the pyrolysis ovens. The end-product of this oxidation would be carbon dioxide which is indistinguishable from the atmospheric carbon dioxide. For the test several organic compounds have been used, for example phenylalanine and benzoic acid. Carboxylic acids are stable intermediates in the oxidation of aromatic compounds and therefore the simplest aromatic carboxylic acid, benzoic acid has been considered to be present on Mars. [2] Along with oxidation of the used compounds also chlorination of the aromatic rings was observed. This reaction leads to a large variety of chlorinated aromatics which would be easy to detect in the GC-MS. A further investigation on the concentration dependency of this reaction is planned. References [1] Geffroy

  9. Plant host and soil origin influence fungal and bacterial assemblages in the roots of woody plants.

    Science.gov (United States)

    Bonito, Gregory; Reynolds, Hannah; Robeson, Michael S; Nelson, Jessica; Hodkinson, Brendan P; Tuskan, Gerald; Schadt, Christopher W; Vilgalys, Rytas

    2014-07-01

    Microbial communities in plant roots provide critical links between above- and belowground processes in terrestrial ecosystems. Variation in root communities has been attributed to plant host effects and microbial host preferences, as well as to factors pertaining to soil conditions, microbial biogeography and the presence of viable microbial propagules. To address hypotheses regarding the influence of plant host and soil biogeography on root fungal and bacterial communities, we designed a trap-plant bioassay experiment. Replicate Populus, Quercus and Pinus plants were grown in three soils originating from alternate field sites. Fungal and bacterial community profiles in the root of each replicate were assessed through multiplex 454 amplicon sequencing of four loci (i.e., 16S, SSU, ITS, LSU rDNA). Soil origin had a larger effect on fungal community composition than did host species, but the opposite was true for bacterial communities. Populus hosted the highest diversity of rhizospheric fungi and bacteria. Root communities on Quercus and Pinus were more similar to each other than to Populus. Overall, fungal root symbionts appear to be more constrained by dispersal and biogeography than by host availability. © 2014 John Wiley & Sons Ltd.

  10. Soil Influences Colonization of Root-Associated Fungal Endophyte Communities of Maize, Wheat, and Their Progenitors

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    Deepak Bokati

    2016-01-01

    Full Text Available Root-associated fungal endophytes are vital component of root microbiome as some mitigate their host’s abiotic and biotic stress. We characterized root-associated fungal endophytes in cereal grains and their progenitors grown on two different soil-types. We aimed at determining how clay and desert soil affects the colonization of root fungal community. Both culture-dependent and culture-independent methods were employed to identify endophytes that successfully colonized greenhouse-grown host plants. The Internal Transcriber Spacer region of fungal ribosomal DNA was utilized for identification purposes. This study revealed soil as a prominent factor influencing the composition of microfungal communities inhabiting the roots of maize (Zea mays subsp. mays and its conspecific progenitor, teosinte (Zea mays subsp. parviglumis. Similar results were found in wheat (Triticum aestivum subsp. aestivum and its progenitor (Triticum monococcum subsp. monococcum. The multidimensional comparisons of Morisita-Horn similarity values of fungal colonists of various host plant taxa indicated that soil plays a primary role in shaping the root fungal community; a secondary effect was plant host identity, even when the plant host is a conspecific. Future studies focused on characterizing root endophytes in other cereal grains, and studying the effect of edaphic factors on fungal colonization, can ultimately contribute to crop productivity.

  11. The influence of biocalcification on soil-cement interlocking block compressive strength

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    Yoosathaporn, S.

    2015-01-01

    Full Text Available Description of the subject. Soil-cement interlocking block is used as the building block for many civil structures in Thailand. The addition of many alternative materials into interlocking block in order to improve compressive strength has been reported. However, there is currently no report on the influence of application of biocalcification or microbiologically induced calcite precipitation (MICP on interlocking block compressive strength. Objectives. This study aimed to investigate the effect of biocalcification on compressive strength of soil-cement interlocking block. Method. Soil bacterium, Bacillus pasteurii KCTC 3558, and Effective Microorganisms (EM were added into interlocking block before molding as the replacement of mixing water. The change of compressive strength in interlocking block at 3, 7, 14 and 28 days of incubation was determined. Results. At 28 days, the compressive strength of interlocking block supplemented with B. pasteurii KCTC 3558 and 5% EM were 7.38% and 9.79% significantly higher than control. Calcium carbonate crystals were also observed under scanning electron microscope which suggested that an increased compressive strength of interlocking block was caused by biocalcification. Conclusions. Our results showed that microbiologically induced calcite precipitation could help increasing the compressive strength of soil-cement interlocking block.

  12. Influence of soil characteristics on the diversity of bacteria in the Southern Brazilian Atlantic Forest.

    Science.gov (United States)

    Faoro, H; Alves, A C; Souza, E M; Rigo, L U; Cruz, L M; Al-Janabi, S M; Monteiro, R A; Baura, V A; Pedrosa, F O

    2010-07-01

    The Brazilian Atlantic Forest is one of the 25 biodiversity hot spots in the world. Although the diversity of its fauna and flora has been studied fairly well, little is known of its microbial communities. In this work, we analyzed the Atlantic Forest ecosystem to determine its bacterial biodiversity, using 16S rRNA gene sequencing, and correlated changes in deduced taxonomic profiles with the physicochemical characteristics of the soil. DNAs were purified from soil samples, and the 16S rRNA gene was amplified to construct libraries. Comparison of 754 independent 16S rRNA gene sequences from 10 soil samples collected along a transect in an altitude gradient showed the prevalence of Acidobacteria (63%), followed by Proteobacteria (25.2%), Gemmatimonadetes (1.6%), Actinobacteria (1.2%), Bacteroidetes (1%), Chloroflexi (0.66%), Nitrospira (0.4%), Planctomycetes (0.4%), Firmicutes (0.26%), and OP10 (0.13%). Forty-eight sequences (6.5%) represented unidentified bacteria. The Shannon diversity indices of the samples varied from 4.12 to 3.57, indicating that the soils have a high level of diversity. Statistical analysis showed that the bacterial diversity is influenced by factors such as altitude, Ca(2+)/Mg(2+) ratio, and Al(3+) and phosphorus content, which also affected the diversity within the same lineage. In the samples analyzed, pH had no significant impact on diversity.

  13. Organic matter and soil water content influence on BRS 188 castor bean growth

    Energy Technology Data Exchange (ETDEWEB)

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

    2008-07-01

    The castor bean culture has been highlighted due to the several applications of its oil, which constitutes one of the best row materials for biodiesel manufacturing, and the base for several other industrial products. The objective of the present work was to study the effect of different soil water and soil organic matter on the castor bean growth. The experiment was conducted from April to August 2006 under greenhouse conditions using a randomized block 2x4 factorial design with two soil organic mater content (5.0 g.kg{sup -1} e 25.0 g.kg{sup -1}), four levels of available water (100, 90, 80 e 70% ) and three replicates. For this, 24 plastic containers, 75 kg capacity, were used on which was grown one plant 120 days after the seedling. At regular intervals the plant height was measured and the results analyzed statistically. For the qualitative treatments (with and without organic matter) the treatment means were compared through the Tukey test. For the quantitative ones (water levels) were used regressions. The castor bean cultivar height was significantly influenced by the organic matter content only after 80 days. Castor bean height increased significantly with the soil water content after 40 days of growing. (author)

  14. Distribution of Soil Organic Carbon and the Influencing Factors in An Oasis Farmland Area

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    WANG Ze

    2014-08-01

    Full Text Available The soil organic carbon(SOC of a typical oasis farmland in middle part of Manasi county of Xinjiang was used as the research ob原 ject. Using remote sensing and lab analysis techniques, influences of soil texture, terrain, land uses, and crop types on SOC content of farmland were studied. Results showed that the SOC distribution in farmland of Manasi was mainly determined by comprehensive natural environmental factors. The SOC content decreased along with the increasing soil depth. For soil textures, the SOC content from high to low was clay loam>powder loam>silty loam. Slope direction had significantly positive correlations with SOC contents at 0~30 cm and 30~60 cm, while altitude and SOC content at 60~100 cm were significantly positive correlation. The SOC content of orchard was the highest, and the uncultivated land was the lowest under different land-use patterns. For different crop planting systems, the order of SOC content was corn field >wine grapes field>cotton field, and the difference was significant.

  15. Diversity and Abundance of Soil Animals as Influenced by Long-Term Fertilization in Grey Desert Soil, China

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    Maibo Jiang

    2015-08-01

    Full Text Available The relationship between soil fauna and different fertilizer management practices is of growing concern. The aim of this research was to investigate the response of soil fauna to fertilization regimes, to explore the relationships among the community of soil animals, soil moisture and crop yields. The application of organic fertilizers (i.e., sheep manure or crop residues increased crop yields and promoted the number of individuals and species of soil fauna owing to the exogenous organic matter that fertilizers provided for the survival and development of soil fauna. Furthermore, the treatments that applied sheep manure (i.e., sheep manure only or nitrogen, phosphorus, potassium and sheep manure plus were significantly beneficial for increasing crop yields and diversity of soil fauna compared to treatments with crop residues returned (i.e., crop residues returned only or nitrogen, phosphorus, potassium and crop residues returned to the field (p < 0.05 due to the response of soil fauna to diverse exogenous nutrients and the effect of soil fertility. Therefore, the finding that soil fauna abundance is significantly positively correlated with soil moisture and crop yield may mean the effects of fertilizer applications on soil animals were partly masked by the soil moisture and crop yield.

  16. Influence of organic amendments on copper distribution among particle-size and density fractions in Champagne vineyard soils.

    Science.gov (United States)

    Besnard, E; Chenu, C; Robert, M

    2001-01-01

    The intensive use for over 100 years of copper sulfate (Bordeaux mixture) to fight against mildew in vineyard soils has led to an important, widespread accumulation of Cu (100 to 1500 mg Cu kg-1 soil). In Champagne vineyards, organic amendments are used currently to increase soil fertility and to limit soil erosion. Organic amendments may have a direct effect on the retention of Cu in the soil. To assess the influence of the organic management on the fate of Cu in calcareous Champagne vineyard soils, we studied Cu distribution (1) in the soil profile and (2) among primary soil particles, in vineyard parcels with different amendments. Amendments were oak-bark, vine-shoots and urban compost. The results were compared with the amount and the distribution of Cu in an unamended calcareous soil. Physical soil fractionations were carried out to separate soil primary particles according to their size and density. Cu has a heterogeneous distribution among soil particle fractions. Two fractions were mainly responsible for Cu retention in soils: the organic debris larger than 50 microns or coarse particulate organic matter (POM) issued from the organic amendments, and the clay-sized fraction < 2 microns. The POM contained up to 2000 mg Cu kg-1 fraction and the clay fraction contained up to 500 mg Cu kg-1 fraction. The clay-sized fraction was responsible for almost 40% of the total amount of Cu in the four parcels. POM was predominantly responsible for the differences in Cu contents between the unamended and the three amended parcels. Our results attested that methods of soil particle-size fractionation can be successfully used to assess the distribution of metal elements in soils.

  17. Ptaquiloside in Pteridium aquilinum subsp. aquilinum and corresponding soils from the South of Italy: influence of physical and chemical features of soils on its occurrence.

    Science.gov (United States)

    Zaccone, Claudio; Cavoski, Ivana; Costi, Roberta; Sarais, Giorgia; Caboni, Pierluigi; Traversa, Andreina; Miano, Teodoro M

    2014-10-15

    The bracken fern Pteridium aquilinum (L.) Kuhn, one of the most common plant species on Earth, produces a wide range of secondary metabolites including the norsesquiterpene glucoside ptaquiloside (PTA). Several studies are present in literature about eco-toxicological aspects related to PTA, whereas results about the effect of growth conditions and soil properties on the production and mobility of PTA are sometimes conflicting and further investigations are needed. The aim of the present work is to investigate the occurrence and possible fate of PTA in soils showing different physical and chemical features, and collected in several areas of the South of Italy. The PTA content was determined in both soil and fern samples by GC-MS; both the extraction protocol and recovery were previously tested through incubation studies. Soils samples were also characterized from the physical and chemical points of view in order to correlate the possible influence of soil parameters on PTA production and occurrence. PTA concentration in P. aquilinum fern seemed to be significantly affected by the availability of nutrients (mainly P) and soil pH. At the same time, PTA concentration in soil samples was always undetectable, independent of the PTA concentration in the corresponding Pteridium samples and pedo-climatic conditions. This seems to suggest the degradation of the PTA by indigenous soil microbial community, whereas incubation studies underlined a certain affinity of PTA for both organic colloids and clay/silt particles. Copyright © 2014 Elsevier B.V. All rights reserved.

  18. Influence of soil texture on the distribution and availability of {sup 238}U, {sup 230}Th, and {sup 226}Ra in soils

    Energy Technology Data Exchange (ETDEWEB)

    Blanco Rodriguez, P. [Departamento de Fisica, Facultad de Ciencias, Universidad de Extremadura, Avd. Elvas s/n, 06071 Badajoz (Spain); Vera Tome, F. [Departamento de Fisica Aplicada, Facultad de Ciencias, Universidad de Extremadura, Avd. Elvas s/n, 06071 Badajoz (Spain)], E-mail: fvt@unex.es; Lozano, J.C. [Laboratorio de Radiactividad Ambiental, Facultad de Ciencias, Universidad de Salamanca, 37008 Salamanca (Spain); Perez-Fernandez, M.A. [Area de Ecologia, Universidad Pablo Olavide, Carretera de Utrera km. 1, 41013 Sevilla (Spain)

    2008-08-15

    The influence of soil texture on the distribution and availability of {sup 238}U, {sup 230}Th, and {sup 226}Ra in soils was studied in soil samples collected at a rehabilitated uranium mine located in the Extremadura region in south-west Spain. The activity concentration (Bq kg{sup -1}) in the soils ranged from 60 to 750 for {sup 238}U, from 60 to 260 for {sup 230}Th, and from 70 to 330 for {sup 226}Ra. The radionuclide distribution was determined in three soil fractions: coarse sand (0.5-2 mm), medium-fine sand (0.067-0.5 mm), and silt and clay (<0.067 mm). The relative mobility of the natural radionuclides in the different fractions was studied by comparison of the activity ratios between radionuclides belonging to the same radioactive series. The lability of these radionuclides in each fraction was also studied through selective extraction from the soils using a one-step sequential extraction scheme. Significant correlations were found for {sup 238}U, {sup 230}Th, and {sup 226}Ra between the activity concentration per fraction and the total activity concentration in the bulk soil. Thus, from the determination of the activity concentration in the bulk soil, one could estimate the activity concentration in each fraction. Correlations were also found for {sup 238}U and {sup 226}Ra between the labile activity concentration in each fraction and the total activity concentration in bulk soil. Assuming that there is some particle-size fraction that predominates in the process of soil-to-plant transfer, the parameters obtained in this study should be used as correction factors for the transfer factors determined from the bulk soil in previous studies.

  19. Characterization on the rhizoremediation of petroleum contaminated soil as affected by different influencing factors

    Science.gov (United States)

    Tang, J.; Wang, R.; Niu, X.; Wang, M.; Zhou, Q.

    2010-06-01

    In this paper, pilot experiments were conducted to analyze the effect of different environmental factors on the rhizoremediation of petroleum contaminated soil. Different plant species (cotton, ryegrass, tall fescue, and alfalfa), addition of fertilizer, different concentration of TPH in soil, bioaugmentation with effective microbial agent (EMA) and PGPR, and remediation time were tested as influencing factors during bioremediation process of Total Petroleum Hydrocarbon (TPH). The result shows that the remediation process can be enhanced by different plants species with the following order: tall fescue > ryegrass > alfalfa > cotton. The degradation rate of TPH increased with increased fertilizer addition and moderate level of 20 g/m2 urea is best for both plant growth and TPH remediation. High TPH content is toxic to plant growth and inhibits the degradation of petroleum hydrocarbon with 5% TPH content showing the best degradation result in soil planted with ryegrass. Bioaugmentation with different bacteria and plant growth promoting rhizobacteria (PGPR) showed the following results for TPH degradation: cotton + EMA + PGPR > cotton + EMA > cotton + PGPR > cotton > control. Rapid degradation of TPH was found at the initial period of remediation caused by the activity of microorganisms, continuous increase was found from 30-90 d period and slow increase was found from 90 to 150 d. The result suggests that rhizoremediation can be enhanced with the proper control of different influencing factors that affect both plant growth and microbial activity in the rhizosphere environment.

  20. Influence of snow cover distribution on soil temperature and nutrient dynamics in alpine pedoenvironments

    Directory of Open Access Journals (Sweden)

    Ermanno Zanini

    Full Text Available In Alpine sites snow is present on the ground from six to eight months per year in relation to elevation and exposure. Water is therefore immobilized into the solid state for the greater part of the winter season and released to the ground in a short period during spring snowmelt. In these areas, snow distribution exercises a fundamental role in influencing soil temperature and nutrient dynamics, in particular of nitrogen, with great consequences on plant nutrition. The dormant vegetation period, the low temperatures and the persistent snow cover suggest that soil biological activity is only concentrated during summer. As a matter of fact, soils covered with a consistent snow cover are isolated from the air temperature and can not freeze during winter. A snowpack of sufficient thickness, accumulated early in winter, insulates the ground from the surrounding atmosphere maintaining soil temperature closed to 0 °C during the whole winter season. The elevation of the snow line and the shorter permanence of snow on the ground, as a result of global warming (IPCC, 1996, 2001, might reduce the insulation effect of the snowpack, exposing soils of the mountain belt to lower temperatures and to a greater frequency of freeze/thaw cycles, which might alter organic matter dynamics and soil nutrient availability. Such thermal stresses may determine the lysis of microbial cells and the consequent increase of nitrogen and carbon mineralization by the survived microorganisms. Moreover, the freeze/thaw cycles can determine the exposure of exchange surfaces not available before, with release of organic matter of non-microbial origin, which may become available to surviving microorganisms for respiration. The reduced or absent microbial immobilization may cause the accumulation of remarkable amounts of inorganic nitrogen in soil, potentially leachable during spring snowmelt, when plants have not still started the growing season. Changes of snow distribution in

  1. Influence of snow cover distribution on soil temperature and nutrient dynamics in alpine pedoenvironments

    Directory of Open Access Journals (Sweden)

    Michele Freppaz

    2011-02-01

    Full Text Available In Alpine sites snow is present on the ground from six to eight months per year in relation to elevation and exposure. Water is therefore immobilized into the solid state for the greater part of the winter season and released to the ground in a short period during spring snowmelt. In these areas, snow distribution exercises a fundamental role in influencing soil temperature and nutrient dynamics, in particular of nitrogen, with great consequences on plant nutrition. The dormant vegetation period, the low temperatures and the persistent snow cover suggest that soil biological activity is only concentrated during summer. As a matter of fact, soils covered with a consistent snow cover are isolated from the air temperature and can not freeze during winter. A snowpack of sufficient thickness, accumulated early in winter, insulates the ground from the surrounding atmosphere maintaining soil temperature closed to 0 °C during the whole winter season. The elevation of the snow line and the shorter permanence of snow on the ground, as a result of global warming (IPCC, 1996, 2001, might reduce the insulation effect of the snowpack, exposing soils of the mountain belt to lower temperatures and to a greater frequency of freeze/thaw cycles, which might alter organic matter dynamics and soil nutrient availability. Such thermal stresses may determine the lysis of microbial cells and the consequent increase of nitrogen and carbon mineralization by the survived microorganisms. Moreover, the freeze/thaw cycles can determine the exposure of exchange surfaces not available before, with release of organic matter of non-microbial origin, which may become available to surviving microorganisms for respiration. The reduced or absent microbial immobilization may cause the accumulation of remarkable amounts of inorganic nitrogen in soil, potentially leachable during spring snowmelt, when plants have not still started the growing season. Changes of snow distribution in

  2. Response of soil microflora to impact of heavy metals in zones of influence of railway transport

    Directory of Open Access Journals (Sweden)

    N. Bobryk

    2016-03-01

    Full Text Available Monitoring research on the areas intensively and continuously affected by technogenic loading has remained topical until nowadays. The soil as a basic component of many ecosystems, including the structure of its microbial cenoses, remains an informative index of a system’s overall stability. The areas affected by railway transport have been scarcely studied. Due to the above, the aim of this work has been to establish the transformation regularities of soil microbial cenoses of territories close to railways and to establish the groups of microorganisms that are a sensitive criterion of technogenic vehicular influence. For the purpose of microbiological research, soil samples were taken at different distances from the railway track (0, 25, 50, 100 and250 m within five monitoring sections of the Tchop – Uzhhorod – Sambor railway (in the territory of Zakarpatska oblast. The number of ecological trophic groups was identified by means of inoculation on nutrient media using the method of serial dilution of soil suspensions. The research showed that in all types of soils that were adjacent to railway tracks, the number of ammonifiers and spore microbiota was high due to the high content of heavy metals (beyond the background levels. Besides, the bacterial microflora on beef-extract agar was characterized by homogeneity with domination of enteric bacteria and spore bacteria. Simultaneously, the numbers of nitrogen-fixing microorganisms, micromycetes, oligonitrophils, amylolytic and pedotrophic microflorae were shown to be low compared to the control. Farther from the railway track, pigmental species of bacteria appeared in the soil samples, attesting to the activity of self-purification processes. Correlation analysis of the data showed that the soil microbiota of the railway-side areas was undergoing changes as affected by heightened contents of heavy metals. Existence of medium and close connections was established between the number of

  3. Program of Research for Forests and Associated Rangelands

    Science.gov (United States)

    Nelson S. Loftus; Joseph G. Massey; [Compilers

    1978-01-01

    This research plan for the Southern Region is a companion publication to the National Program of Research for Forests and Associated Rangelands. While the national program reflects both regional and national priorities, this plan provides details on forestry research matters concerning the South. For the reader's convenience, background information on development...

  4. Ecology and utilization of desert shrub rangelands in Iraq

    NARCIS (Netherlands)

    Thalen, Derk Catharinus Peter

    1979-01-01

    When grazing is the accepted land use, vegetation is the key resource. The present study deals with the desert shrub rangelands of lraq, which contain the major characteristics of such an area, having been under grazing for many centuries. Emphasis is given to the ecology and utilization of the

  5. Parameterization of erodibility in the Rangeland Hydrology and Erosion Model

    Science.gov (United States)

    The magnitude of erosion from a hillslope is governed by the availability of sediment and connectivity of runoff and erosion processes. For undisturbed rangelands, sediment is primarily detached and transported by rainsplash and sheetflow (splash-sheet) processes in isolated bare batches, but sedime...

  6. 75 FR 8036 - Monitor-Hot Creek Rangeland Project

    Science.gov (United States)

    2010-02-23

    ... Forest Service Monitor-Hot Creek Rangeland Project AGENCY: Forest Service, USDA. ACTION: Notice of intent...-Toiyabe National Forest will prepare an environmental impact statement (EIS) on a proposal to authorize..., Little Fish Lake, Monitor Complex, Saulsbury and Stone Cabin allotments have active term grazing permits...

  7. Session A6 Rangelands as dynamic systems — Fragmentation of ...

    African Journals Online (AJOL)

    In this symposium, we consider the effects of fragmentation of rangelands and ensuing loss of biological complexity for a variety of processes including behaviour and performance of large herbivores, responses of plant communities to herbivory, and functioning of human social and economic systems. We invite posters that ...

  8. Rangeland Ecosystem Services: Nature's Supply and Humans' Demand

    Science.gov (United States)

    Ecosystem services are the benefits that society receives from nature and they include the regulation of climate, the pollination of crops, the provisioning of intellectual inspiration and recreational environment, as well as many essential goods such as food, fiber, and wood. Rangeland ecosystem se...

  9. Scale, heterogeneity and secondary production in tropical rangelands

    African Journals Online (AJOL)

    This paper will review our current understanding of scale-related effects on livestock production in tropical rangelands and herbivore-plant interactions at patch to landscape scales. We use published information and results from recent empirical studies in northern Australia and elsewhere to elucidate scale-related effects ...

  10. Vulnerability of amphibians to climate change: implications for rangeland management

    Science.gov (United States)

    Karen E. Bagne; Deborah M. Finch; Megan M. Friggens

    2011-01-01

    Many amphibian populations have declined drastically in recent years due to a large number of factors including the emerging threat of climate change (Wake 2007). Rangelands provide important habitat for amphibians. In addition to natural wetlands, stock tanks and other artificial water catchments provide habitat for many amphibian species (Euliss et al. 2004).

  11. Livestock versus Wildlife Ranching in Kenyan Rangelands: A Case ...

    African Journals Online (AJOL)

    Livestock versus Wildlife Ranching in Kenyan Rangelands: A Case Study of Laikipia District Ranches. ... The results reveal a web of interactive factors involving land tenur, livestock development, disease control, marketing and environmental conservation that need to be considered if the newly emerging mixed -livestock ...

  12. Post-wildfire regeneration of rangeland productivity and functionality ...

    African Journals Online (AJOL)

    Wildfires can have significant impacts on rangeland productivity and functionality causing substantial economic losses to affected farmers. In August 2011, such wildfires swept through the North West province of South Africa, destroying large areas of grazing and farm infrastructure. There is little information available on ...

  13. Botanical Criteria of Baharkish Rangeland in Quchan, Khorasan ...

    African Journals Online (AJOL)

    ADOWIE PERE

    resolution of ecological problems such as biological conservation and natural ... agriculture, biology and pharmacy, this study set out to evaluate ..... Ghahreman, A (1979-1992).Colorful flora of Iran. Research Institute of Forests and Rangelands,. Tehran (In Persian). Ghahreman, A (1994). Plant systematics: cormophytes of ...

  14. Session A4 Rangelands as dynamic systems Desertification ...

    African Journals Online (AJOL)

    Session A4 Rangelands as dynamic systems Desertification: patterns and processes in Africa. M Timm Hoffman, Michael Darkoh. Abstract. The United Nations Convention to Combat Desertification (UNCCD) makes special mention of the desertification problem in Africa. This session will provide an up to date overview of ...

  15. Yield Response of Mediterranean Rangelands under a Changing Climate

    NARCIS (Netherlands)

    Daliakopoulos, Ioannis N.; Panagea, Ioanna S.; Tsanis, Ioannis K.; Grillakis, Manolis G.; Koutroulis, Aristeidis G.; Hessel, Rudi; Mayor, Angeles G.; Ritsema, Coen J.

    2017-01-01

    Understanding the Mediterranean rangelands degradation trends is a key element of mitigating their vulnerability and enhancing their resilience. Climate change and its inherent effects on mean temperature and the precipitation variability can regulate the magnitude, frequency and duration of

  16. Ecology and Conservation of Acacia senegal in the Rangelands ...

    African Journals Online (AJOL)

    Ecology and conservation status of Acacia senegal in the rangelands of Luwero and Nakasongola Districts were assessed between November 2002 and February 2003. Sixty plots measuring 50 x 50 m were laid at 50 m intervals along six 1,000 m transects, and the diameter at breast height (DBH), of Acacia .fellegal trees ...

  17. Monitoring Insect and Disease Impacts on Rangeland Oaks in California

    Science.gov (United States)

    Tedmund J. Swiecki; Elizabeth A. Bernhardt; Arnold Richard A.

    1991-01-01

    We developed methods to assess the impacts of diseases and arthropods on sapling and mature rangeland oaks, and applied these methods at 18 sample plot locations in northern California. The impact of arthropod damage was generally rated as minor. Leafy mistletoe (Phoradendron villosum) was found on 5 percent of the rated trees. There was a slight...

  18. A review of climate change effects on terrestrial rangeland birds

    Science.gov (United States)

    D. M. Finch; K. E. Bagne; M. M. Friggens; D. M. Smith; K. M. Brodhead

    2011-01-01

    We evaluated existing literature on predicted and known climate change effects on terrestrial rangeland birds. We asked the following questions: 1) How does climate change affect birds? 2) How will birds respond to climate change? 3) Are species already responding? 4) How will habitats be impacted?

  19. The challenge of integrated rangeland monitoring: synthesis address

    African Journals Online (AJOL)

    The utility of monitoring and its guiding principles will only work effectively where good environmental governance is practiced by users and producers affecting rangeland ecosystems. Keywords: adaptive management, complex, environmental governance, human impacts, multi-scale, socio-ecological. African Journal of ...

  20. Reshaping women's land rights on communal rangeland | Kleinbooi ...

    African Journals Online (AJOL)

    This paper aims to contribute to the debates on communal rangelands and analyses the gendered dimension of land rights and land access in the rural areas of Namaqualand. The actual gender relations within rural communities and the emergence of strategies that are being pursued in communal land processes are ...