نتایج جستجو برای: soil physical quality index

تعداد نتایج: 1841178  

Different land uses have various effects on the changes of soil properties. The purpose of this study was to evaluate the effects of natural forest, needle-leaved plantation and rangelands of central Alborz on new indices of soil quality (i.e. organic matter stratification, carbon management index and soil biological activities). For this purpose, eight samples from organic layer (litter) and m...

2007
Alexandre Marco da Silva Lilian Casatti Clayton Alcarde Alvares Aline Maria Leite Luiz Antonio Martinelli Steven F. Durrant

Soil loss expectation and possible relationships among soil erosion, riparian vegetation and water quality were studied in the São José dos Dourados River basin, State of São Paulo, Brazil. Through Geographic Information System (GIS) resources and technology, Soil Loss Expectation (SLE) data obtained using the Universal Soil Loss Equation (USLE) model were analyzed. For the whole catchment area...

Journal: :مهندسی عمران فردوسی 0

compressibility characteristics of fine-grained soils are often the most important parameters for settlement evaluation of the founded layers. the compression index which is the slope of virgin curve is usually for determination of settlement potential of fine grained soils. in this research, the effects of different physical and index properties of soil samples were investigated on compression...

2008
Carmen Trasar-Cepeda María Carmen Leirós Fernando Gil-Sotres

Human activity is one of the main causes of the physical, chemical and biological degradation of soils. This degradation implies a change in soil quality as it involves both a decrease in productivity and changes in the ecological functions of the soil. The objective of the present study was to investigate the effect of soil use on soil biochemical properties, with the aim of providing data tha...

2014
Wei Zhou Teng-Fei Lv Yong Chen Anthony P Westby Wan-Jun Ren

Paddy-upland rotation is an unavoidable cropping system for Asia to meet the increasing demand for food. The reduction in grain yields has increased the research interest on the soil properties of rice-based cropping systems. Paddy-upland rotation fields are unique from other wetland or upland soils, because they are associated with frequent cycling between wetting and drying under anaerobic an...

Journal: :Ecotoxicology 2014
Xuelian Bao Qi Li Jianfeng Hua Tianhong Zhao Wenju Liang

Ultraviolet-B (UV-B) radiation and elevated tropospheric ozone may cause reductions in the productivity and quality of important agricultural crops. However, research regarding their interactive effect is still scarce, especially on the belowground processes. Using the open top chambers experimental setup, we monitored the response of soil nematodes to the elevated O3 and UV-B radiation individ...

2003
Douglas L. Karlen Craig A. Ditzler Susan S. Andrews

The soil quality concept evolved throughout the 1990s in response to increased global emphasis on sustainable land use and with a holistic focus emphasizing that sustainable soil management requires more than soil erosion control. The concept includes two areas of emphasis—education and assessment—both based soundly on principles of soil science. Soil quality test kits, farmer-based scorecards,...

2009
Guilherme M. Chaer David D. Myrold Peter J. Bottomley

Recent studies have suggested that the organic matter contents of undisturbed soils (under natural vegetation) are in equilibrium with biological and biochemical properties. Accordingly, we hypothesised that such equilibria should be disrupted when soils are subjected to disturbance or stress, and that measurement of this disruption can be expressed mathematically and used as a soil quality ind...

Journal: :پژوهش های خاک 0
جلیـل کاکه دانش آموخته کارشناسی ارشد گروه مهندسی علوم خاک دانشگاه تهران علی اصغر ذوالفقاری استادیار گروه مناطق خشک دانشکده کویر شناسی دانشگاه سمنان منوچهر گرجی دانشیار گروه مهندسی علوم خاک- پردیس کشاورزی و منابع طبیعی دانشگاه تهران

soil particle-size distribution (psd) is one of the most important physical attributes due to its great influence on soil physical, chemical, and biological properties. water infiltration rate, land-use change, soil erosion, and biological soil crusts (bscs) may influence psd in a soil. the multifractal measures were useful tools in characterization of psd in soils. the objective of the current...

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