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通过对沙坡头荒漠地区人工植被固沙区生物土壤结皮与固沙区外天然沙丘沙以及天然植被红砂、珍珠分布区砂粘土在不同初始含水率(θi)条件下土壤水平入渗过程的对比试验研究,探讨土壤质地以及θi对水平入渗系数(λf)、剖面平均含水率(θm)状况的影响。生物土壤结皮对降水入渗量的截持作用大于沙丘沙,因而将显著地改变降水入渗过程中土壤水分的再分配格局,减少降水对深层土壤(沙丘沙)的有效补给。通过对土壤剖面平均含水率θm与距离湿润锋前缘0～5cm、5～10cm处体积含水率θfA、θfB比较,生物土壤结皮的θm、θfA和θfB分别约为沙丘沙的1.5倍。
Through the comparison of soil infiltration process between biological soil crusts and natural sand dunes outside the sand fixation area and soil samples from the red sand and pearl distribution areas with different initial moisture content (θi) in artificial desertification area of Shapotou desertification area Experimental study was conducted to investigate the effects of soil texture and θi on the horizontal infiltration coefficient (λf) and the average sectional water cut (θm). The interception of biological soil crusts on infiltration capacity is greater than that of dune sand, which will significantly change the redistribution pattern of soil moisture during rainfall infiltration and reduce the effective recharge of deep soil (dune sand) by precipitation. By comparing the average water cut θm of the soil profile with the volumetric water cut θfA and θfB of 0 ~ 5cm and 5 ~ 10cm from the front of the wetting front, the θm, θfA and θfB of the biological soil crusts are respectively about 1.5 times that of the sand dunes.