The meteorological data were collected at the desert-oasis ecotones to study rainfall characteristics and response of soil moisture to rainfall pulse in desert regions of the Heihe River basin. The results indicated that the rainfall pattern was characterized as rainfall pulse in arid regions. Soil moisture differed significantly before and after rainfall, and decreased gradually with increasing of the soil depth in desert regions. Soil moisture differed significantly for different rainfall volumes, soil depths, before and after rainfall, and the interactive effects (P<0.0001), which indicated that the response of soil moisture to rainfall pulse, was significant. Rainfall pulse led to a sharp increase of soil water content after rainfall, then decreased slowly under the conditions of evapotranspiration until rainfall supplement. The variation pattern of time series for soil moisture before and after rainfall can be fitted to semivariograms models. The structural ratios (C/(C0+C)) of soil water content were bigger than 0.910, and there was possibility that the spatial heterogeneity mainly resulted from structural reason since the stochastic variation is smaller than the structural variation, which can reflect that there was a quite strong autocorrelation pattern for soil moisture in time scales. Rainfall pulse decreased the difference of spatial structure for soil moisture, and it led to decrease of the spatial heterogeneity in time series.

Download Here