几种土壤密度随土壤含水量变化的模拟研究

Simulation of Bulk Density Changes with Soil Water Content for Several Soils

以湖北地区的黄棕壤、红壤、潮土、水稻土为供试土壤,研究了土壤密度随土壤含水量的变化,并进行了数值模拟,结果表明,所有供试土壤随着重量含水量的降低,土壤密度都会逐渐增大,土壤密度(B)随含水量(θg)变化的关系可用指数模型B=a e-bθg描述,且其精度较高。模型中不同土壤的a值和b值有所不同,一般土壤黏粒含量高,黏粒中膨胀型矿物多,有机质含量少,在原状土中的水稳性团聚体含量小,则会引起土壤收缩曲线模型的a值和b值大。不同土壤的a值和b值的大小,则由这些影响因素的综合影响效果决定。

Taking the yellow brown soil,red soil,chao soil,rice soil in Hubei area as studying soil,the soil bulk density change with soil water content of variable bulk density soils is studied and simulated.The results show that with the decrease of the weight water content（θg）,the soil bulk density（B）increases gradually for all the tested soils,the change relationship between soil bulk density and soil water content can be described with the exponential model B=a e-b θg for high precision.The a-value and b-value are different in model for different soils.For general soil,the clay content and the expandable minerals content is high,the organic matter content is small,the water-stable aggregate content is small in the undisturbed soil.This will lead to the bigger a-value and b-value in soil contraction curve.The size of a-value and b-value for different soils are decided by integrated influencing effects of these factors.