土壤质地对坡地土壤水分运动与转化特征的影响研究

Effects of Soil Texture on Soil Water Movement and Transport on Slope Land

通过室内模拟降雨试验,研究了杨凌塿土、安塞黄绵土和神木绵砂土的水分迁移特征。结果表明,随着土壤粘粒含量的增加,坡面产流开始时间提前,坡地平均径流系数、径流量和泥沙量呈增加趋势,入渗率和累计入渗水量呈减少趋势。3种土壤降雨入渗率均可用Kostiakov公式拟合,塿土、黄绵土和绵砂土坡地的平均入渗率分别为0.32、0.83和0.88 mm/min。湿润锋运移速度应该与土壤砂粒百分含量和土层含水量的增量呈正相关关系。为了提高雨水利用率,减少水土流失量,建议加强塿土坡地的保护性耕作措施。

The mechanism of soil water movement and transport is necessary for agricultural management with different soil textures. According to the results of simulation rainfall experiments, the transport traits of soil water on loess slope lands with different soil textures, Yangling sandy clay soil, Ansai loam, Shenmu silt loam, respectively, are investigated. It shows that the initiation runoff time, runoff and sediment also climb with the increase of soil clay particle percent, while the infiltration rate and the cumulate infiltration water reduce with that. The infiltration rate for those soils in the process of rainfall can be well simulated with the Kostiakov equation. The mean infiltration rate for Yangling sandy clay soil, Ansai loam, Shenmu silt loam is 0.32 mm/min, 0.83 mm/min and 0.88 mm/min, respectively. The velocity of wetting front decline should be positive relation to the soil sandy particle percent and the adding soil water. To promote the rare rainfall and lesson the water and soil loss, protective farming measures are suggested, especially for Yangling sandy clay soil.