毛乌素沙地流动沙丘不同深度土壤渗漏特征

沙地的土壤深漏是沙地水分循环及水量平衡中的重要环节,对这一分量的准确测算,能够增进对沙地降雨的分配、转移及运输过程规律的认识。利用土壤深层水量渗漏测试记录仪(YWB-01),对毛乌素沙地典型的流动沙丘50、100 cm和200 cm的3个层次的土壤渗漏水量进行定点实时监测,定量分析降雨条件下沙地土壤渗漏特征,得出以下结论:(1)在降雨条件下,2016年4—6月3个沙层的渗漏过程都不明显,从7月开始,渗漏过程与降雨过程的一致性随沙层的增加而逐渐减弱;(2)随沙层深度的增加,累计渗漏天数以及连续渗漏天数在增加,累计渗漏水量、最大日渗漏水量逐渐减小,渗漏水量的波动也逐渐减小;渗漏水量10 mm的天数和渗漏水量所占的比例明显减少;(3)对降雨量和各沙层渗漏水量日、周、半月、月累积量之间进行相关分析和线性拟合后发现,越往深处渗漏水量对降雨的响应越弱,月渗漏水量与月降雨量的关系更密切。

Analysis of the soil percolation characteristics at different depths of a mobile sand dune in the Mu Us sandy land

Soil percolation is an important part of the water cycle and water balance in sandy land. Accurately estimating this component could enhance understanding of the distribution, transfer, and transportation processes for rainfall in sandy land. In this study, the percolation at 50 cm, 100 cm, and 200 cm depth in a typical mobile sandy dune on the Mu Us sandy land was monitored in real time using a YWB-01 percolation recorder. The soil percolation characteristics in sandy land under rainfall conditions were analyzed, and the following conclusions were drawn: (1) under rainfall conditions, the percolation process between April and June, 2016 in the three layers was not obvious. From July, the consistency of the percolation and rainfall processes gradually weakened as depth increased. (2) The total percolation days and the continuous percolation days rose when depth increased, but the total percolation, daily percolation, and the daily percolation fluctuation gradually decreased. The proportion of the number of days of percolation > 10 mm and the percolation amounts on those days decreased. (3) The results showed the percolation response to rain weakened as depth increased, and that monthly percolation and monthly rainfall were the most closely related according to the correlation analysis and the linear fitting between rainfall and percolation by day, week, half-a-month, and month.