中国沙漠(地)深层渗漏量及动态特征

Deep Soil Water Infiltration and Its Dynamic Characteristics in Chinese Deserts

土壤水分深层渗漏是沙区水循环的重要环节,深层渗漏的定量测定对沙区水资源评估及水量平衡研究具有重要意义。本文采用YWB-01型土壤深层水量渗漏测试记录仪对中国毛乌素沙地等六大沙漠(地)降雨入渗到深层土壤的渗漏水量进行实时动态监测。结果表明:流动沙丘降雨渗漏补给量存在明显的时空差异,与降雨时空变化特征具有相对一致性,降雨格局是影响深层渗漏过程的主要因素,随降雨增大渗漏补给量增加,半干旱区降雨量与渗漏量显著正相关(p<0.05),干旱区相关性不显著(p>0.05);观测期内正镶白旗、伊金霍洛旗、阜康流动沙丘土壤200cm以下渗漏量为48.5、146.8、1.0mm,分别占同期降雨的21.4%、33.3%、1.3%;乌审旗、磴口150cm以下渗漏量为1009.6、52.6mm,分别占同期降雨的55.7%、12.7%。不同气候区固定沙丘渗漏量基本没有差异,降雨格局不是影响水分深层渗漏的主导因素,而植被覆盖的影响占主要作用,且沙丘植被盖度>45%时深层渗漏量不超过同期降雨的2.0%。中国沙区深层土壤水分补给主要来自于强降雨或高频次小降雨事件,特别是干旱区降水少、频次低,其深层土壤水分补给更加依赖于强降水。

Deep soil water rainfall infiltration is an important part of the water cycle in desert areas.It has important significance for water resources assessment and water balance.The YWB-01 Deep Soil Infiltration Water Recorder was used to measure the quantity of rain infiltration into deep soil,in six locations in China:the Horqin,Hunshandake and Mu Us Sandy Land,Hobq,Ulan Buh and Gurbantonggut deserts over a long period.The results showed that deep soil infiltration had significant differences consistency with temporal and spatial characteristics of rainfall in shifting dunes,which rainfall patterns was the main factors affecting the deep infiltration,rainfall and the deep infiltration amount was significantly(p<0.05)positive correlation in semiarid areas,but the correlation was not significant(p>0.05)in the arid areas.The shifting dunes deep soil rainfall infiltration(200 cm),48.5 mm,146.8 mm and 1.0 mm in the observation period,composing21.4%,33.3% and 1.3% of the total precipitation in Baiqi,Yiqi and Fukang,respectively.In Wushen and Dengkou,deep soil rainfall infiltration(150 cm below)reached 1 009.6 and 52.6 mm mm in the total observation period,composing 55.7% and 12.7%,respectively,in shifting dunes.The deep infiltration had no significant differences in the fixed dunes,where the vegetation was the main factors affecting the deep infiltration rather than rainfall.Moreover,the deep infiltration was not more than 2% of the rainfall under the condition for vegetation cover more than45%.The deep infiltration recharge was mainly from heavy rainfall or high frequency small rainfall,especially,the less rainfall and the low frequency rain in arid areas,its deep soil water recharge more dependent on heavy rainfall.