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.