[1] Application of time domain reflectometry (TDR) in soil hydrology often involves the conversion of TDR-measured dielectric permittivity to water content using universal calibration equations (empirical or physically based). Deviations of soil-specific calibrations from the universal calibrations have been noted and are usually attributed to peculiar composition of soil constituents, such as ...

Soil depth is an important input parameter in hydrological and ecological modeling. Presently, the soil depth data available in national soil databases (STATSGO, SSURGO) is provided as averages within generalized land units. Spatial uncertainty within these units limits their applicability for spatially distributed modeling. This work reports a statistical model for prediction of soil depth in ...

in this study, the process-based watershed model, soil and water assessment tool (swat), was used for simulating hydrology and sediment transport in the gharesou watershed and for identifying critical areas of soil erosion and water pollution. after model calibration and uncertainty analysis using sufi-2 (sequential uncertainty fitting, ver. 2) method, the outputs of the calibrated model were u...

The objective of the research was to model water quality using the Soil and Water Assessment Tool (SWAT) interfaced with ArcView GIS. SWAT requires the integration of a range of GIS data layers; digital elevation model, soil types, land use, stream networks, water quality monitoring sites, point pollution sources and climatic observations. Prior to modeling water quality with SWAT, ArcView was ...

Soil apparent electrical conductivity (ECa) has been used as a surrogate measure for such soil properties as salinity, moisture content, topsoil depth (TD), and clay content. Measurements of ECa can be accomplished with commercially available sensors and can be used to efficiently and inexpensively develop the dense datasets desirable for describing within-field spatial variability in precision...

soil water content is one of the most important parameters for estimating irrigation frequency and providing the plant’s water requirement. since measurement of soil water content is both expensive and time consuming, water movement models are used to estimate these values. in this study, leachw model was used to estimate soil water content for two “dry” (20-29 aug) and “wet” (1-6 jul) periods ...

In this study, the process-based watershed model, Soil and Water Assessment Tool (SWAT), was used for simulating hydrology and sediment transport in the Gharesou watershed and for identifying critical areas of soil erosion and water pollution. After model calibration and uncertainty analysis using SUFI-2 (Sequential Uncertainty Fitting, ver. 2) method, the outputs of the calibrated model were u...

Traditional methods of measuring soil organic carbon (SOC) are not adequate for accurate evaluation of C sequestration nor to meet environmental safety requirements. Methods that permit accurate assessment of SOC, which are environmentally healthy, and yet feasible for use in developing countries are needed. Initial and ignition temperatures were adjusted so that loss on ignition (LOI) measures...