黄土丘陵区不同土地利用方式土壤入渗规律研究

在延安燕沟试验区建立不同下垫面(草地、刈割草地、翻耕草地、灌木地、刈割灌木地、翻耕灌木地)小区,分析了30场人工模拟降雨试验的入渗资料,结果表明,植被覆盖地平均入渗率是刈割地的1.2倍,是翻耕地的2.0倍;在地表坡度7°,草灌地土壤容重分别为1.27和0.99 g/cm3条件下,坡面平均入渗率与降雨强度具有极显著的抛物线函数关系.草地、刈割草地、灌木地、刈割灌木地雨强分别达到1.62,2.21,2.49和1.71 mm/mim时,平均入渗率具有最大值,分别为1. 17,0.97,1.67和1.51 mm/min;但翻耕草地、翻耕灌木地与此相反,雨强分别达到1.36和1.68 mm/min时,平均入渗率具有最小值,分别为0.379和0.382 mm/min;Horton入渗公式能较好地模拟不同土地利用方式下降雨的入渗过程.

Infiltration Characteristics Under Different Land Uses in the Loess Hilly Area

Six plots(grass slope,grass-cut slope,plowed grass slope,shrubby slope,shrub-cut slope,and plowed shrubby slope) in the Yan'gou watershed were constructed and infiltration data for thirty simulated rainfall events were analyzed.Results showed that the average infiltration rate on vegetable slope was 1.2 times greater than that on shrub-cut slope and 2.0 times greater than that on plowed slope.For the soil bulk density of 1.27 or 0.99 g/cm3 on grass slope or shrubby slope,the average infiltration rate varied with rainfall intensity as a parabolic function at a slope of 7 degree.When rainfall intensities for grass slope,grass-cut slope,shrubby slope,and shrub-cut slope were 1.62,2.21,2.49,and 1.71mm/mim,the maximum averaged infiltration rates were 1.17,0.97,1.67,and 1.51mm/min,respectively.In contrast,when rainfall intensities for plowed grass slope and plowed shrubby slope were 1.36 and 1.68mm/min,the minimum averaged infiltration rates were 0.379 and 0.382mm/min,respectively.In conclusion,the Horton's model better simulates the infiltration process under the condition of the different land uses.