流动沙丘水分深层入渗量与降雨的关系

Relationship between rainfall and deep layer infiltration of mobile dunes in the Mu Us Sandy Land,China

为分析流动沙丘水分深层入渗与降雨的关系,采用YWB-01型水分深层渗漏记录仪,运用土壤水动力学原理,研究了毛乌素沙地流动沙丘降雨入渗水分传递过程及地表以下150 cm深度入渗补给特征。结果表明：流动沙丘深层土壤水分来源主要为降雨入渗,2010年入渗补给量为141.4 mm,2011年为355.8 mm,分别占同期降雨量的55.1%和68.2%。深层入渗主要补给期为5—11月,期间补给量占全年总量的95%。当土壤水分条件保持在田间持水量范围之内时,降雨过程对土壤150 cm深度的补给作用主要受降雨量和降雨强度的影响,入渗量与降雨量呈极显著正相关（P〈0.01）,降雨通常在30~48 h后渗透补给到150 cm深层土壤,入渗补给速率在前3~5 h呈快速上升趋势,3~8 h左右达到最大值,此后缓慢下降,整个入渗补给过程可以持续96 h以上。

In order to analyze the relationship between deep layer moisture infiltration and rainfall in mobile dunes,using YWB-01 deep layer moisture infiltration recorder and soil water dynamics theory,this study explains the rainfall infiltration moisture transfer process in Mu Us Sandy Land mobile dunes,as well as the infiltration recharge characteristics at the soil layer of 150 cm deep. The results showed that： the major source of deep layer soil moisture in mobile dunes was rainfall infiltration. The infiltration recharge amount was 141. 4 mm for 2010 and 355. 8 mm for 2011,counting for 55. 1% and 68. 2% of the total rainfall amount of that year. The major recharging season of deep layer infiltration lasted from May to November,and the recharge amount during these months counted for 95% of the total annual amount. When the soil moisture condition remained within the field moisture capacity,rainfall ＇s recharging effect on 150 cm deep soil layer was mainly influenced by rainfall amount and density,with a significant positive correlation（ P 0. 01） between infiltration and rainfall amount. Water usually infiltrated into the 150 cm deep soil layer at 30 to 48 hours after the start of rainfall. The infiltration recharging rate increased rapidly in the first 3 to 5 hours,reaching its maximum at 3 to 8 hours,before decreasing slowly afterwards. The entire infiltration recharging process could last for longer than 96 hours.