典型地块粉砂壤土水分扩散率测定

Determination of the Water Diffusivity in Silt Loam in Typical Area

以新疆石河子垦区最早实施滴灌棉田地块为研究对象,采用水平土柱法研究粉砂壤土水分扩散率。结果表明:Boltzmann参数随着土壤含水率的减少而增大,其中40~60 cm土层随着土壤含水率的减少Boltzmann参数变幅最为明显;相同含水率情况下,40~60 cm土层水分扩散率最高,其水分扩散率大小表现为:40~60 cm>0~20 cm>20~40 cm;并用RETC软件对参数进行拟合,由VGM模型和BCM模型的实测值与模拟值均方根误来分析,最终确定BCM模型拟合表达式作为粉砂壤土水分扩散率。

The first drip irrigation cotton fields in the Shihezi area of Xinjiang are studied. The water diffusivity at different depths of silt loam is studied by horizontal column infiltration in indoor laboratory. The resuhs show that： with the decrease of water content, Boltzmann parameters increase, and the phenomenon is mostly restricted at 40- 60 cm depth soft ; under the same water content, the highest level of soil water diffusivity can be found at 40~ 60 cm depth and there has no significant difference at other depths, and the order of soil water diffusivity from large to small is 40-60, 0 ~ 20, 20 ~ 40 cm. Furthermore, the parameters are fitted and verified with RETC software, and the root mean square error between simulation values and measured values of VGM model and BCM model is analyzed. The BCM model is selected as the expression formula for the soil moisture diffusivity at different depths of silt loam.