黄土高原区域尺度土壤干燥化的空间和季节分布特征

为掌握黄土高原土壤干燥化程度的空间分布特征，定量评价雨季前、后土壤干燥化程度，于2013年在黄土高原南北方向布设一条样带（N=86），获取雨季前、后0~5 m剖面土壤含水量。采用地统计学方法分析了土壤干燥化指数的空间分布规律及变异特征。结果表明:在黄土高原地区，土壤干燥化程度存在明显的纬度地带性，且雨季前土壤干燥化指数的空间变异程度高于雨季后；经过雨季降水的补给，土壤干层在一定程度上得到修复，且中部地区的修复效果明显优于南部及北部地区；土壤干燥化指数剖面分布特征在雨季前、后的差异主要表现在浅层0~2.3 m土层，这主要归因于降水对浅层土壤水分的补给。

Regional spatial and seasonal characteristics of soil desiccation on the Loess Plateau

This study was to understand the spatial distribution characteristics of soil desiccation and quantitatively evaluate the soil desiccation conditions within different seasons on the Chinese Loess Plateau. For this purpose, soil water contents of the 0—5 m profile were measured before and after the rainy season in 2013, respectively, along a regional transect (N=86) established from the south to the north. The spatial distribution and variation characteristics of soil desiccation index (I_SD) were analyzed using the geostatistical method. Results showed that the spatial pattern of soil desiccation had an obvious latitudinal zonality in the region. The spatial variability of I_SD before rainy season was higher than that after rainy season. Dried soil layers were recovered to some extent after supplementation of precipitation after the rainy season. The degree of the recovery was higher in the central part of the region than that of the south and north areas. Furthermore, the difference of I_SD distribution characteristics along the soil profiles mainly occurred in the top 0—2.3 m soil layers. This difference was mainly attributed to the limited recharge from rainfall in the shallow layers.