砒砂岩—黄土沟谷土壤含水量的时空变化

Spatiotemporal Variation of Soil Moisture Content in the Soft-rock Loess Gully

以晋、陕、蒙交界地区常见的砒砂岩—黄土丘陵沟谷为研究对象,分别于2005年7月和10月对沟谷不同部位土壤含水量进行了测定。结果表明,其时空变化特征明显。(1)沟谷不同部位土壤平均含水量大小为7月份:沟谷底部14.44%,阳坡顶部9.29%,阴坡顶部9.01%,阴坡中部8.25%,阳坡中部6.36%;10月份:沟谷底部9.96%,阴坡顶部9.81%,阳坡中部9.48%,阴坡中部9.09%,阳坡顶部8.06%。(2)砒砂岩平均含水量季节变幅小,属稳定型;黄土及有冲积层的黄土平均含水量季节变化较大,属波动型。(3)在砒砂岩剖面上,泥岩含水量显著大于砂岩,砒砂岩坡面平缓的地段贮水能力比陡的地段大。(4)在黄土剖面上,明显出现土壤干层现象,在夏季、秋季降雨较少的情况下,土壤水分会严重降低,土壤水分处于负补偿状态,土壤干层距地表更深。在半干旱地区的砒砂岩—黄土丘陵沟壑区,黄土剖面土壤干层的发生是一个自然现象,随降雨量的多寡,呈消长状态。

A special loess gully type,soft-rock loess gully,is distributed in the border area of Shanxi,Shaanxi,and Inner Mongolia,in which water loss and soil erosion are serious.In the study,soil moisture characteristics in the soft-rock loess gully were measured and analyzed.The main results are as follows:(1) In midsummer(July),the averaged soil moisture content of the various parts of the gully was obviously different.The order of landform units from high to low,in terms of soil moisture content,was the bottom of...