三峡库区不同水保措施下紫色土水分特征曲线特征及模型拟合

土壤水分特征曲线是反映土壤持水性、供水性及水分有效性等基本特性的重要曲线，是定量研究土壤水滞留与运移十分重要的土壤水动力学参数之一。通过分析比较等高绿篱农业系统和石坎梯田农业系统的紫色土水分特征曲线，探讨不同水保措施下紫色土水分特征曲线特征，将实测数据对国内外常见的几种土壤水分特征曲线模型分别进行拟合，并优选一种适合三峡库区紫色土的水分特征曲线模型。结果表明：不同处理紫色土水分特征曲线存在较大差异。同一土壤水吸力水平下，新银合欢处理土壤持水量最高，其次为石坎梯田处理，自然坡面处理土壤持水量最小。随土壤水吸力增大，各处理间差异越明显。Gardner模型和Van Genuchten模型均可用于描述三峡库区紫色土水分特征曲线，根据不同的需要选取不同的模型，Gardner模型适合简单快捷的田间土壤水分管理，Van Genuchten模型适合进一步土壤水力传导参数的推求应用.

ANALYSIS AND MODEL FITTING FOR PURPLE SOIL WATER RETENTION CURVE UNDER DIFFERENT MEASURES OF SOIL AND WATER CONSERVATION IN THE THREE GORGES RESERVOIR AREA

Soil water retention curve is one of the important soil hydrodynamics parameters in quantitative study of soil water retention and movement,which can reflect the basic properties of soil,such as water retention,water supply,and water availability,et al. In this thesis,characters of purple soil water retention curves under different measures of soil and water conservation were discussed,through analyzing soil water retention curves under contour hedgerow-intercroping system and rock ridge terrace-intercroping system. Then the measured datas were taken to fit four common soil water retention curve models respectively,in order to select the best model for the purple soil in the Three Gorges Reservoir Area. The results showed that the difference of purple soil water retention among different treatments could be observed easily. Based on the same soil water suction,soil water content was the highest for contour hedgerow treatment,secondly for rock ridge terrace treatment,and the lowest for the control. With the increase of soil water suction,the difference among treatments was more obvious. Both Gardner model and van Genuchten model were suitable for expressing purple soil water retention curve. According to practical needs,one of them could be selected. Generally, Gardner model was suitable for simple and quick field soil water management, and van Genuchten model was suitable for soil hydraulic properties estimation and application.