科尔沁沙地沙丘-丘间低地降雨前后土壤水分分布特征

发布时间：2019-04-13 08:11

【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(P0.05);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。
[Abstract]:Taking the fixed dune-hilly lowland landscape unit in Horqin Sandy Land as the research object, under the condition of high vegetation growth and long-term drought, The characteristics of soil moisture distribution and rainfall replenishment in different microtopography before and after moderate rainfall (22.6 mm) were analyzed. The results showed that, in the horizontal direction, there was a significant difference in the average soil moisture of 0 ~ 90 cm depth at different sites before and after rainfall. Before rain, the order of the order was lower (10.30%) in the lower part of the dune (1.18%) in the top (0.98%) in the top of the sand dune (0.75%) in the upper part of the sand dune; The soil moisture increased by 2.33, 3.50, 1.77 and 0.34 percentage points in the top, upper, lower and interhilly lowlands after rain, respectively, and in the vertical direction, the depth distribution of soil moisture before and after rainfall was related to the horizontal position. The surface soil moisture was very small before rain. The top of sand dune was at the top of the sand dunes, and the depths of the top were 40 ~ 100, 20 ~ 50 and 120 ~ 200 cm, respectively. The soil water content of the lower and lower dunes increased with the depth and reached the saturation water content. The increasing depth of soil water storage in the top, upper, lower and interhilly lowlands after rain is 0 / 110, 0 / 110, 0 / 50 and 0 / 90 cm, respectively, accounting for 12.4%, 13.3%, 9.7% and 14.6% of the rainfall, respectively, while the soil water storage increases in the upper, lower and interhilly lowlands are 12.4%, 13.3%, 9.7% and 14.6% of the rainfall, respectively. The increment of water storage in 0 / 10 cm soil layer was significantly higher than that in the top and upper part of the sand dunes, and there was no significant difference in the increment of water storage in different parts of other depths (P0.05). Under the condition of no rainfall for a long time, the soil water condition in the top and upper part of sand dunes tends to worsen. It is necessary to take certain thinning measures to maintain the dynamic balance of soil moisture, which is conducive to vegetation restoration and desertification reversal.
【作者单位】：中国科学院沈阳应用生态研究所;中国科学院大学;
【基金】：国家重点基础研究发展计划项目(2013CB429902) 国家科技支撑计划子课题(2015BAD07B050501)资助
【分类号】：S152.7

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