Background In order to explore the response mechanism of soil moisture to rainfall under different vegetation restoration measures in alpine sandy land, the optimum soil layer for sand-fixing plants to plant and better play its role in soil and water conservation.and its response to different rainfall events under three years' planting in Gonghe Basin, Qinghai province, including high vertical net cage sand barrier, wheat straw checkered sand barrier+Hedysarum scoparium, wheat straw checkered sand barrier+Caragana korshinskii, wheat straw checkered sand barrier+Artemisia desertorum, and wheat straw checked sand barrier+Helianthus tuberosus, so as to provide theoretical basis for scientific planting of soil depth of sand-fixing plants.

Methods Taking the three-year-old high net cage sand barrier, wheat straw checkered sand barrier+Hedysarum scoparium, wheat straw checkered sand barrier+Caragana korshinskii, wheat straw checkered sand barrier+Artemisia desertorum. and wheat straw checkered sand barrier+Helianthus tuberosus planting in Gonghe Basin, Qinghai Province as the research objects, the rainfall and sand barrier types of 0-140 cm(10, 20, 40, 60, 80, 100 cm) in the study area were measured by 2900ET weather station and ECH₂O respectively.

Results 1) From August 2020 to August 2021, the rainfall in the study area was mainly concentrated in April to September, with low-frequency light rain as the main event, and the rainfall event < 2 mm accounted for the highest of the total rainfall events (38.98%) and the lowest contribution rate (6.12%). The types of sand barriers can be divided into slow accumulation period (January-April), consumption period (May-June), accumulation period (July-September) and stable period (October-December) according to the monthly change of total soil water storage capacity, and all of them reach the peak in August, among which the soil water storage capacity of the vertical sand barrier is the highest (47 563.54 mm), and that of H. tuberosus sand barrier is the lowest (25 564.09 mm). 2) When the rainfall is less than 5 mm, the soil moisture of H. tuberosus sand barrier 0-10 cm, flower stick sand barrier and A. arenaria sand barrier 0-20 cm fluctuates. When the height is 5-18 mm, the vertical sand barrier is 0-10 cm, the Caragana sand barrier, A. arenaria sand barrier and H. tuberosus sand barrier are 0-20 cm, and the water content of the flower bar sand barrier is 0-100 cm. > 18 mm, the vertical sand barrier is 0-10 cm, Caragana sand barrier, A. arenaria sand barrier and H. tuberosus sand barrier are 0-60 cm, and the soil moisture of the flower bar sand barrier is 0-140 cm.

Conclusions Based on the response of soil moisture to rainfall and the characteristics of soil moisture replenishment in the process of desertification land control under different vegetation mapping measures in this area, it is suggested to repair it from May to June.