Dynamics and response mechanism to precipitation of farmland soil moisture

Abstract

Soil moisture (SM) plays an important role in the eco-hydrological processes in the sandy land, and hence is a critical ecological limiting factor. We analyzed the farmland SM dynamics and its response to precipitation based on the 0∼160 cm SM and precipitation data from April 17 to September 15 in 2015, Horqin Sandy Land. The preliminary results shown that (1) During the experiment, the number of precipitation events was mainly <3.0 mm and accounting for 60.47% of the total precipitation events; And >15 mm occurred less and accounting for 4.65% of the total precipitation events, but its precipitation amount was relatively high (35.4 mm), accounting for 25.81% of the total precipitation. (2) With the increase of soil depth, SM firstly increased, then decrease, and finally increased again, and the SM of 40∼60 cm and 140∼160 cm soil layers were higher, while 0∼20 cm and 100∼120 cm were lower. (3) The SM was lower in April and September, and the seasonal variation of SM varies greatly depending on the soil depth. (4) After the different characteristic precipitation events, the SM of 0∼60 cm and 120∼160 cm continued to increase with the increase of soil depth, while the SM of 60∼120 cm varied with soil depth showed a more complicated trend.