Abstract:In order to explore the soil water recovery under deep ground cover in the loess hilly region, a simulated soil column with depth of 1000cm and diameter of 80cm was constructed in the hilly hills of northern Shaanxi, and there were six treatments of surface: the film mulching was provided with 16 small holes with an asymmetric diameter of about 2mm for rainwater to enter and regularly updated every year;the stone mulching was uniform graveled with diameter from 2cm to 5cm, covering a thickness of 10cm;the branch mulching was cut jujube branches, the length was about 10cm, evenly covered after drying, the thickness was 10cm;bare land without any covered;planting jujube with a diameter of 1cm and height of 50cm, without any other covering measures, regularly removed weeds;planting locust with a diameter of 1cm and a height of 50cm, without any other covering measures, regularly removed weeds. Soil moisture content of sloping farmland was taken as reference. Analysis of the positioning monitoring data for 2014—2017 showed that at the end of the trial period, taking the average water content of sloping farmland as the recovery target, the film mulching, stone mulching, branch mulching and bare soil moisture recovery depth was 1000cm, 1000cm, 700cm and 480cm;taking the actual soil water content of sloping farmland as the recovery target, the film mulching and stone mulching soil moisture recovery depth was 1000cm, the branch mulching recovery depth was 740cm, and the bare land recovery depth was 440cm. From the degree of recovery, the results were consistent. The water storage capacities of film mulching, stone mulching, branch mulching, bare land, jujube tree and locust were increased by 1211.4mm, 853.4mm, 662.5mm, 523.2mm, 17.8mm and -235.7mm, respectively. The precipitation storage efficiency were 63.4%, 42.4%, 29.4%, 23.0%, -8.5% and -20.3%, respectively. The water consumption area of four years old jujube was ranged from 0cm to 300cm, its annual average evapotranspiration was 586.4mm, locust consumed water up to 1000cm, and its annual average evapotranspiration was 666.5mm, which was 1.1 times of jujube. The research result had positive significance for the largearea dry soil restoration in the loess area and the rational selection of artificially planted plants.
