桂西北岩溶山区峰丛洼地土壤水分动态变化初探

Dynamic Change of Soil Water in Peak-Cluster Depression Areas of Karst Mountainous Region in Northwest Guangxi

土壤水分是岩溶山区植被恢复和生态环境建设的关键性限制因素。在桂西北岩溶山区峰从洼地，分析了不同利用方式坡面、洼地土壤水分的动态变化规律，结果表明：坡面土壤水分（0～20cm）为中等变异，不同利用方式间具有一定的差异，自然灌丛、撂荒地土壤含水量较高，但板栗、木豆林地土壤含水量较低，且易受外界条件的干扰，其栽种早期应注意采取一定的蓄水保墒措施；与坡地相比，洼地受外界条件的干扰相对较小，土壤剖面含水量为增长型，其变化主要发生在表层，为中等变异；土壤水分沿坡面的分布规律较为复杂，在植被类型相对一致的条件下，坡位的影响相对较小。

Soil water is the critical factors for vegetation rehabilitation and eco-environmental construction in karst mountainous region. The dynamic changes of soil water on hillslope and in depression areas under various land use types were analyzed in peak-cluster depression areas of karst mountainous region in northwest Guangxi. The results showed that soil water （0-20cm） on hillslope was moderate variation, and had some differences among various land use types. Natural shrub and abandoned lands had higher water contents and anti-disturbance abilities than those cultivated with chestnut and Cajanus cajan （L.） Millspaugh, so the latter needed some water-conserving measures during their early growth period. Sloping land was easier to be disturbed by environmental conditions than depression, where soil water increased with the increase of depth and its changes mostly took place at surface soil layers with moderate variation. Soil water movement on hillslope was complex and slope positions had small effects on its distribution along hillslope with the same vegetation type.