前期土壤含水量对坡面产流产沙起始时间的影响

Effects of antecedent soil moisture content on initial time of runoff and sediment yield of slope surface

以水稻土为研究对象,采用室内降雨模拟试验方法,通过控制坡地不同的前期土壤含水量和坡面坡度,研究了3种降雨强度(I1≈0.6 mm/m in,I2≈1.2 mm/m in和I3≈3.0 mm/m in)下水稻土的前期土壤含水量对坡面产流产沙起始时间的影响。结果表明,水稻土的土壤饱和含水量不随坡面坡度的变化而改变,而是维持一个常量;坡面坡度越小,幂函数对于前期土壤含水量与坡面产流产沙起始时间拟合的相关性越显著;前期土壤含水量在36.49%～50.93%时的水稻土最早发生水力侵蚀。研究成果可为湿润半湿润地区的水土资源管理提供基础理论依据。

Taking the paddy soil as the research object,we studied the effects of antecedent soil moisture content on initial time of runoff and sediment yield of slope surface through the rainfall simulation experiment,by controlling the different antecedent soil moisture contents and the slope gradient of sloping land under 3 different rainfall intensity conditions of I1≈0.6 mm/min,I2≈1.2 mm/min and I3≈3.0 mm/min.The results show that the saturated moisture content of paddy soil does not vary with the slope gradient but keeping a constant.Correlation of the power function fitting is more significant for the smaller slope gradient.In addition,the water erosion occurs the earliest in the paddy soil if its antecedent soil moisture content is between 36.49%~50.93%.The result can provide a theoretical basis for water soil resources management in humid and sub-humid regions.