Research On Soil Moisture Characteristic Curve Based On Clay And Loam

Soil water characteristic curve is the relationship between the expression of soil water potential and soil water content curve of soil water characteristic curve is a function of a complex,measure the accurate and complete the function curve of the impact on many factors,so commonly used empirical formula to fitting out the moisture characteristic curve.Based on the root distribution of cereal crops,this paper mainly studies the soil moisture characteristic curves of clay and loam,and predicts the functional curve types of the four models.Between the roots of wheat,millet and other suction range and root distribution mainly in the 0-30cm,this article selects two germplasm in loam and clay soil,measured the 0-10cm soil layer,10-20cm soil layer,and 20-30cm soil layer of soil water characteristic curve.The measured values of soil water characteristic curve of two soil layers were measured by strain gauge method.With the help of Matlab software,the measured data was put into the Gardner model,the Van-Genuchten model,the Mckee-Bumb model and the Frdlund-Xing model.The conclusions are as follows:(1)Van Genuchten model and Frdlund-Xing model is suitable for describing the experience of the clay moisture characteristic curve model.(2)Van Genuchten model is applicable to describe loam soil water characteristic curve,0-10 cm soil layer Frdlund-Xing model applicable to describe loam 10-20cm soil layer soil water characteristic curve,Mckee-Bumb loam 20-30cm soil layer model of soil water characteristic curve.(3)Gardner model does not apply to describe clay and loam soil water characteristic curve,at the same time Mckee-Bumb model fitting clay water content of the saturated moisture content and residual income is bigger than the actual.(4)The Van-Genuchten model can better fit the residual moisture content of clay.This article also on Gardner model and Van Genuchten model,Mckee-Bumb model and Frdlund-Xing model 4 experience has carried on the simple mathematical function curve analysis.The conclusions are as follows:(1)Gardner model in soil near saturation fitting effect will be bad,suitable for water saturated with poor soil.(2)The Van Genuchten model and the Frdlund-Xing model function curve are similar to the inverted "S" type,which is suitable for the soil with the inverted "S" in the measured soil water characteristic curve.(3)The Mckee-Bumb model is suitable for soils with poor water retention.(4)The prediction of the model curve can accurately and effectively select the empirical model when the model is selected.