浑善达克沙地土壤水分深层渗漏的动态特征

Dynamic Characteristics of Deep Soil Water Leakage in Otindag Sandy Land

[目的]分析浑善达克沙地土壤水分深层渗漏的时空分布特征及饱和条件下的土壤水分入渗,为沙地水分循环、水量平衡、水资源评估提供理论依据。[方法]运用土壤深层渗漏水量记录仪对浑善达克流动沙地、小叶锦鸡儿(植被覆盖度20%~30%)半固定沙地和小叶锦鸡儿(植被覆盖度40%~50%)固定沙地200 cm以下深层渗漏情况进行连续监测。[结果]以小降雨事件为主的半干旱区浑善达克沙地流动、半固定、固定不同类型沙地的土壤水分深层渗漏特征与降雨特征均有一致性,但渗漏量存在时空分布差异。流动沙地渗漏量最大,饱和条件下的入渗率最快,持续时间最长,半固定沙地为次,固定沙地为后。流动沙地深层渗漏与月降雨量呈显著相关(p<0.05),而固定沙地深层渗漏与降雨量在时间上没有一致性,无明显集中渗漏补给期。[结论]半固定、固定沙地的植被影响了深层渗漏,植被覆盖度越高影响力度越大,流动沙地更能有效储存水分,并对地下水有补给作用。

[Objective]The temporal and spatial distribution characteristics of deep soil water leakage and infiltration under saturated conditions in Otindag sandy land were analyzed in order to provide a theoretical basis for the evaluation of the sandy land water cycle,water balance,and water resources.[Methods]Deep soil leakage in Otindag sandy land semi-fixed caragana microphylla(vegetation coverage 20%~30%)and fixed deep seep of Caragana microphylla(vegetation coverage 40%~50%)below 200 cm was continuously monitored by a recording apparatus.[Results]In the semi-arid,low-rainfall area of Otindag sandy land,the characteristics of deep soil water leakage in different types of sandy land were consistent with the characteristics of rainfall,but the spatiotemporal distribution of leakage was different.The leakage was largest and the infiltration rate was fastest under saturated conditions,while the duration was longest in the mobile sandy land.There was a significant correlation between deep leakage and monthly rainfall in the mobile sandy land(p<0.05),and the fixed sand had no correlation in time and there was no obvious concentrated recharge period of seepage.[Conclusion]The vegetation in the semi-fixed and fixed sandy land affected deep leakage,and the higher the vegetation coverage,the greater the impact.The mobile sandy land can store more water and replenish underground water.