【摘要】 以科尔沁沙地固定沙丘-丘间低地景观单元为研究对象,在植被生长旺盛期且长时间干旱条件下,对中等降雨(22.6 mm)前后不同微地形土壤水分分布特征和降雨补给情况进行分析。结果表明:水平方向上,降雨前后不同部位0~90 cm深度平均土壤水分有显著差异,雨前其大小顺序为丘间低地(10.30%)>沙丘下部(1.18%)>沙丘顶部>(0.98%)>沙丘上部(0.75%);雨后沙丘顶部、上部、下部和丘间低地土壤水分分别增加了2.33、3.50、1.77和0.34个百分点;垂直方向上,降雨前后土壤水分的深度分布与水平位置有关;雨前表层土壤水分均很小,沙丘顶部、上部分别在40~100、20~50和120~200 cm深度有较弱的高值区,沙丘下部和丘间低地土壤水分随深度增大,直至饱和含水量;雨后沙丘顶部、上部、下部、丘间低地土壤储水量增加的深度范围分别是0~110、0~110、0~50和0~90 cm,其储水量增量分别占降雨的12.4%、13.3%、9.7%和14.6%,其中丘间低地0~10 cm土层储水量增量显著高于沙丘顶部和上部,其他深度不同部位储水量增量差异不显著(P<0.05);在长时间无降雨条件下,沙丘顶部和上部土壤水分状况趋于恶化,有必要采取一定间伐措施,使土壤水分维持动态平衡,才有利于植被恢复和沙漠化逆转。更多还原

【Abstract】 In this paper,a typical landscape unit,dune- interdune in Horqin Sandy Land was selected as study object,and the characteristics of soil moisture distribution and rainfall recharge along terrain before and after a moderate rainfall event( 22. 6 mm) were analyzed. The results showed that,in the horizontal direction,there were significant differences among the mean soil moisture content( SMC) of 0- 90 cm depth at different locations. Before rainfall,the order of SMC at different locations was interdune( 10.30%),downslope( 1.18%),dune top( 0.98%)and upslope( 0.75%); after rainfall,the rate of SMC increment was 2.33% for dune top,3.50%for upslope,1.77% for downslope and 0.34% for interdune. In the vertical direction,soil moisture distribution with depth before and after rainfall was related with locations. Before rainfall,surface SMC was quite low and mean SMC was slightly higher at 40-100 cm depth of dune top,and at 20- 50 cm and 120- 200 cm depth of upslope. At downslope and interdune,SMC increased with depth up to saturated values. After rainfall,soil water storage increased at 0- 110 cm,0-110 cm,0-50 cm and 0-90 cm depth at dune top,upslope,downslope and interdune,which were 12.4%,13.3%,9.7% and 14.6% of rainfall,respectively. At 0- 10 cm layer,soil water storage increment at interdune was significantly higher than that of dune top and upslope,and there were no significant differences at other layers among different locations( P<0.05). During the period with no rain for long time,soil water at dune top and upslope was in deficit,and it is necessary to take measures to maintain a dynamic balance in soil water,which is good for vegetation restoration and desert reversal.更多还原