The research of soil moisture difference using the delaying effect of the precipitation on the vegetation

A new method to analyze the differences of soil moisture in an area is advanced. Soil moisture is related closely to vegetation growth. An experiment was conducted in the Yellow River Basin in China. The change of vegetation cover is the result of many factors. We postulate that soil moisture in the Yellow River Basin is mainly determined by the precipitation. The delaying effect of the precipitation on the vegetation cover was analyzed in the Yellow River Basin using the cross partial correlation index between precipitation and NDVI. The cross partial correlation index has already excluded the impact of temperature on vegetation cover. Different delaying effects represent different soil moisture. The delaying interval can be adapted to measure soil moisture difference at different levels. On the basis of the above result, the difference of soil moisture in the Yellow River Basin was analyzed, and the difference map of soil moisture in the Yellow River Basin was made.