Changes of surface soil relative moisture content in Hengduan Mountains, China, during 1992–2010

Abstract

The detection of soil moisture content is very valuable in the study of hydrological processes and environments. The purpose of this study was to characterize the spatial and temporal variations of soil moisture contents in 0–50 cm soil layer depths in the Hengduan Mountains, and to make inferences regarding the environmental factors that influence such variability. Soil moisture contents were measured with a drying method at ten day intervals. Based on soil relative moisture content data from 16 observation stations during 1992–2010, spatial and temporal changes of soil relative moisture content were analyzed using Kriging interpolation. Results indicated that the soil relative moisture content in the Hengduan Mountains has been increasing since 1992 with a rate of 0.51% y−1. The soil relative moisture contents were relatively high in the southwest and the northeast, and low in the southeast and the northwest. The value of soil moisture increases with increasing soil depth. For seasonal variation, the increasing trends of soil relative moisture content in spring and summer were greater than that in autumn and winter. The main meteorological factors which lead to the increasing of soil relative moisture content were the increase of precipitation and decrease of evaporation. In addition, local topography and vegetation cover were positive influencing factors in soil moisture variations in a specific region.