干热河谷阴坡和阳坡土壤水分动态研究

采用对比法,分析了干热河谷阴坡和阳坡土壤水分动态特征.结果表明：旱季干旱指数大、持续时间长是干旱河谷土壤水分严重亏损及植被恢复困难的直接原因;旱季阳坡水面蒸发总量较阴坡高18.04%;地表30cm土层的水分变化最剧烈,变异系数超过0.6,该层次的土壤水分含量阳坡和阴坡差异不明显;但随土层厚度的增加,两者差异逐渐增大,至60 cm土层达3.84%;在70 cm土层内,阳坡无水分调节层,而阴坡水分调节层厚度达30 cm.

Dynamic Comparison of Soil Water between Shady Slopes and Sunny Slopes in the Dry-hot Valley

By the contrastive analysis method researches were made on the dynamic characters of soil water on shady slopes and sunny slopes in the hot-dry river valleys of Pahzhihua. The results indicated that direct reasons for causing the severe shortage of soil water and the difficult restoration of vegetation were an enormous evaporating capacity and longterm drought in the dry season. The evaporating amount of water surface of the sunny slope was 18.04 % more than that of the shady slope in the dry season. In the 30 cm thick soil layer, the change of soil moisture was very severe, the variation coefficient was over 0.6,hut the difference of soil moisture between the shady and sunny slopes was not evident. Below the 30 cm thick soil layer, the difference of soil moisture between both slopes gradually enlarged with the increase of soil layer thickness, and up to 60 cm thick soil layer the differeace was 3.84%. In the 70 cm thick soil layer,there was no adjusting layer of water on the sunny slope, and yet the thickness of water-adjusting layer was up to 30 cm on the shady slope.