Effects Of Coverage, Rainfall Intensity And Slope Degree On Soil Erosion Of Typical Urban Green Spaces

Urban green spaces is an important part of urban ecological environment construction, it is helpful to study the law of soil erosion of urban green spaces to prevent soil erosion in urban green spaces, which makes it of theoretical and practical importance. In this paper, the influence factors on the soil erosion of two typical urban green spaces were studied. Experiments were conducted in Jiufeng test base rainfall hall of Beijing Forestry University for 2 years. Two types of underlying surfaces (sandy soil planted with Tall Fescue, clay planted with Bermudagrass), three coverages (90%,60%,0%),3 slope degrees (5,10,20 degrees), fixed rainfall (90 mm) and three rainfall intensities (30,60,90 mm/h)were settled altogether to achieve the environment. The main conclusions of this paper are as follows:(1) 90%,60% coverage of Tall Fescue and Bermudagrass can delay the sediment time. The time of initial sediment yield was positively correlated with coverage, and was negatively correlated with rainfall intensity and slope degree. The initial sediment yield was linearly related to the coverage, rainfall intensity and slope degree of two kinds of grassland.(2) There appeared bare gully erosion on sandy loam under experimental conditions, and the development of gully slope was positively correlated with rainfall intensity and slope degree. With the increase of slope degree and rainfall intensity, the estate sand rates of two green land were increased accordingly.(3)60% coverage of Tall Fescue can effectively reduce the bare land sediment, reduction rate reaches more than 95%, the reduction rate of 60% coverage of Bermudagrass on bare land sediment was over 90%.(4) Coverage is the most influenced factors on two grass estate sediment and the correlation between the coverage and sediment yield is significant. Slope degree has a greater impact on the Tall Fescue sediment than rainfall intensity while the condition is on the contrary when it comes to Bermudagrass.(5)Two sediment yield models under the experimental conditions of grasslands were established, the predicted data was well correlated with measured values. The models was identified that they can be used to predict the sediment yield only in the same conditions.