Process of Runoff and Sediment Yield and Nutrient Transport Characteristics in Desert Steppe

[Objective] The summer rainfall intensity in the desert steppe is strong and concentrated, and the harm of hydraulic erosion is serious. It is of great significance for soil and water conservation in this area to clarify the process of runoff and sediment yield, as well as the law of nutrient transport. [Methods] The experiment is based on natural rainfall observation data and artificial rainfall simulation methods, studying the runoff and sediment production processes, nutrient transport patterns in the desert steppe area, and investigating the impact of vegetation on runoff and sediment production through different vegetation treatments. [Results] (1) Different vegetation treatments had different effects on soil and water conservation. Among the three different treatments, the soil and water conservation effect of natural grassland the best, and the runoff reduction rate and sediment reduction rate were 11.37% and 49.67%, respectively. (2) The process of runoff and sediment production would change the material composition of surface soil, make the surface soil coarse-grained, and also affect soil nutrients. After rainfall, the sand content increased by 5.97%~15.71%, and the soil available N, P and organic matter decreased by 40.84%, 27.08%, 33.49%, respectively. (3) The runoff and sediment yield increased with the increase of slope and rainfall intensity, and the power function can better fit the relationship between rainfall duration and runoff and sediment yield. With the increase of rainfall intensity, the peak runoff yield increased by 6.70 L on average when the slope was 5°~25°. When the rainfall intensity is 0.6~2.0 mm/L, the inflection point of the sediment yield increase rate will appear between the slope of 15°~20°. [Conclusion] The research results can provide a theoretical reference for the comprehensive prevention and control of soil and water loss in desert steppe areas, which is helpful in improving the ecological environment of desert steppe regions and carrying out soil and water conservation efforts in this area.