Experimental Study On Soil Hydro-physical Characteristics And Spatial Variability Of Sloping Farmland In Semi-arid Of West Heilongjiang

Soil is an extremely important component in the natural ecological environment, and is closely related to human life and production. However, soil is not a homogeneous body, but rather a continuous space-time variant, with a high degree of spatial variability, both in large scale or small. Even in the area of same soil texture and the same time, the value of soil properties at different spatial locations also have significant differences, which makes the movement parameters of soil moisture spatial variability also different. Soil moisture movement parameters include water characteristic curve, diffusivity and hydraulic conductivity. It characterized the nature and characteristics of the soil itself, is essential information applying mathematical and physical methods to analyze soil moisture movement quantitatively, but also essential basis mathematical modeling of soil water movement. The study has sloping farmland of semi-arid area in west of Heilongjiang Province for example, selects the water content, saturated water content, bulk density, organic matter and mechanical composition as analysis indexes, based on lots of testing and analysis, studied space variation of soil hydro-physical properties preliminarily in the region.Based on experiments, through analyzing all commonly used models of water characteristic curve, diffusivity and hydraulic conductivity, it established single parameter models of soil moisture movement parameters, the models are simulated with high accuracy, and with only one parameter, only one point can be measured on the moisture movement curve, thus obtained the whole moisture movement curve by the model, through the verification, the model has relatively high accuracy, and can be applied to predict.Combined the method of classical statistics with geostatistics, analyze and compare the spatial variability of soil physical and chemical parameters (water content, saturated water content, bulk density, organic matter and mechanical composition)quantitatively. And with geographic information system, using software ARCGIS9.0, plotted the spatial distribution map of soil physical and chemical parameters, more visually displaying their spatial distribution pattern.