| As an important grain production base in China,the thickness of the black soil layer in northeast China decreases year by year due to soil erosion,and even the phenomenon of "broken skin yellow" appears.Due to the slow process of soil formation,it takes hundreds of years to form 1 cm of black soil,making black soil almost a non-renewable resource.Hedgerows have the characteristics of low cost and can effectively improve soil properties and reduce soil erosion.Hedgerows are an important measure for slope farmland management in the black soil region of northeast China.However,the mechanism of sediment reduction on slope is not clear yet.Therefore,in the northeast black earth area as the research object,this study set three different configuration of plant hedge,using of sands contained stream flow to the scour simulation test,study of shrub and grass hedge hedge,cluster hedge three different herbs hedge configuration of slope runoff and sediment migration patterns,with the aid of ree tracer method analysis of erosion and sediment sources of slope,and then parse different configuration hedgerow corrosion mechanism.The study reached the following conclusions:(1)The three hedgerows with different configurations were all able to inhibit runoff outflow,and the dense hedgerows had the best effect,followed by the bushy hedgerows,and the last was the hedgerows.All hedgerows had good flow and sediment reduction benefits,among which the flow and sediment reduction benefits of grass hedgerows were 9.41% and73%,the flow and sediment reduction benefits of bushy herbaceous hedgerows were 6.24%and 64.77%,and the flow and sediment reduction benefits of hedgerows were 3.57% and49.20%.(2)Erosion sediment sources are different on different slopes.In the bare slope,erosion sediment mainly comes from 1 m in the middle and lower part of the slope,and erosion is the most serious in the position where the hedgerows are installed in the slope.On the dense hedgerow slope,the sediment mainly comes from the belt and is seriously eroded.The erosion sediment of herbaceous hedgerows and hedgerows mainly came from the belt and the belt.(3)The sediment intercepted by the three hedgerows was mainly large-diameter sediment,and the interception effect was the same as that of sediment reduction.The three hedgerows all had good soil conservation benefits in the belt,and compared with bare land,they all eroded the soil under the belt,especially the dense hedgerows.Alley cropping density on the surface of the slope is larger,the interception effect,the better,will bring the runoff and sediment in taking position in deposition and change slope surface micro topography,at this point,for a long time in the alley cropping exit can form,led to increasing down by soil runoff erosion,think in terms of the slope surface is not on slope surface protection of alley cropping density,the greater the effect is better.The innovation of this paper lies in the use of rare earth elements to mark the hedgerows slope,and the study of the effects of hedgerows on different positions of the slope belt,middle and lower belt.The mechanism of hedgerow erosion control was revealed by combining the benefits of sediment reduction,erosion process,sediment particle size distribution and sediment source tracing. |
