Different Impacts of Rainfall Intensity on Surface Runoff and Sediment Loss between Huang-mian Soil and Brown Soil
Huang-mian soil and brown soil are typical soils in Loess Plateau and Yimeng mountainous area, respectively. The differences of surface runoff and sediment loss between the two soils are important to special environmental protection management in two areas. In order to study the impacts of rainfall intensity on surface runoff and sediment from Huang-mian soil and brown soil, four simulated rainfalls were applied on fields with different soils on a laboratory scale. Huang-mian soil under 60×10-3 m hr-1 had the shortest runoff occurrence time, while brown soil under 30×10-3 m hr-1 had the longest time; Huang-mian soil under 30×10-3 m hr-1 had the most sediments; Huang-mian soil has less loss of phosphorus (P) in concentration than brown soil, which explains why Loess Plateau has more soil and water loss but less eutrophication than the Yimeng mountainous area. Under the same rainfall intensity, Huang-mian soil had more runoff volume than brown soil; however, higher rainfall intensity decreased the difference. Increasing rainfall intensity had more impact on sediment content in brown soil than Huang-mian soil. It also had more impact on nitrate nitrogen (NO3--N) content in brown soil than ammonia nitrogen (NH4+-N) loss content in Huang-mian soil. Finally, suggestions were provided to reduce the harm of N and P loss in Huang-mian soil and brown soil regions.