Influence Of Vegetation Distribution Pattern On Soil Erosion On Slope In The Loess Plateau

Water resources are the limiting factor of the Loess Plateau ecosystem.Seeking a slope vegetation pattern with higher soil and water conservation benefits within the range of water carrying capacity is helpful to control soil erosion and achieve sustainable development of regional vegetation construction.The vegetation in the runoff plot of Wangdonggou watershed at Changwu Loess Plateau Agricultural Ecological Experiment Station(Changwu Station)was treated in different ways,including control(no mowing,T1),upper and lower staggered uniform mowing(T2),Cut evenly from top to bottom(T3),cut evenly from bottom to top(T4),cut centrally from top to bottom(T5),and cut centrally from bottom to top(T6)),resulting in different slopes Vegetation pattern to quantify its impact on slope erosion and sediment yield,the following main results were obtained(1)The runoff,sediment yield and runoff velocity increased significantly with the decrease of vegetation coverage(P<0.05),while the initial runoff time decreased significantly with the decrease of vegetation coverage(P<0.05).The runoff,sediment yield and runoff velocity of bare land increased by 8.4,13.7 and 1.2 times,respectively,and the runoff time decreased by 56% when the vegetation coverage was 85.7%.(2)When the vegetation coverage was lower than 71.4%,the landscape trait index and spread of vegetation patches on the slope had a significant impact on the slope runoff(P<0.05);when the vegetation coverage was lower than 57.1%,the vegetation patch Fragmentation and spread had significant effects on runoff velocity(P<0.05).When the vegetation coverage was 28.6%,the runoff and runoff velocity decreased with the increase of the vegetation patch landscape trait index(LSI).(3)When the vegetation coverage is greater than or equal to 71.4%,keep the upper part of the slope intact,cut the vegetation on the lower part of the slope evenly,and no runoff on the slope;under the same vegetation coverage condition,keep the lower part of the slope intact and evenly cut the vegetation on the upper part of the slope,the slope is eroded to produce sand.When the vegetation coverage was higher than 28.6%,the runoff and runoff velocity increased with the increase of vegetation relative position(RP),and the runoff time decreased with the increase of RP.Studies have shown that vegetation pattern can significantly affect the process of slope erosion and sediment production.Runoff time,runoff and sediment yield were significantly correlated with vegetation coverage,vegetation distribution and vegetation location.Vegetation can effectively reduce the erosion and sediment production on the slope,especially the vegetation on the upper part of the slope has a better effect of preventing soil erosion.When using vegetation to control soil erosion on the slope,the vegetation coverage should be increased first,and then the vegetation on the upper part of the slope should be protected and constructed,and the vegetation should be distributed evenly on the slope as much as possible.