Study On The Sediment Yield And Runoff Under Different Combination Of Vegetation With Artificial Simulation Rainfall On Degraded Grassland

Vegetation is an important factor in affecting soil erosion, understanding the effect of Grassland Vegetation on runoff and sediment in Xilin Guole is the important content in investigating its water conservation benefits of vegetation. In this paper, selected Agropyron mongolicum, Bromus ineris, Melilotus suaveolens, Medicago sativa as the main objects of study, by way of artificial rainfall in field experiments to investigate runoff and sediment characteristics change in slope under different rainfall intensity, vegetation mixing ways and water retention agent, the main conclusions are as follows:(1) when vegetation combined with different gradient of water retention agent, water retention agent is administered with an initial increase in the amount of time followed by a delayed runoff, the delay time of runoff increased. When the rainfall intensity is 0.73mm/min, the initial runoff time was 7.4min in natural grass cell which was applying Og/m2 with water retention agent, when applying 50g/m2 of water retention agent, the delay time of rainfall is 15min; the same amount of application of water retention agent on time delay effect on vegetation initial runoff and runoff, performed that for the same amount of water retention agent initial runoff in artificial grassland was later than natural grassland, when applying 50g/m2 water retention agent and rainfall intensity is 1.03mm/min, the later initial runoff time of Bromus ineris and Melilotus suaveolens was 5.73min and 3.16min later than natural grassland. Same rainfall intensity, run off delay time under same amount of water retention agent application rate was not very different, about 0.5min or so.(2)After water retention agent was applied in different vegetation configurations, performed that with increased water retention agent, runoff was decreased. When rainfall intensity was 1.03mm/min, the production flow was 27.82L in Agropyron mongolicum and Melilotus suaveolens that applying Og/m2 with water retention agent, while it was 15.02L more than when applied with 50g/m2 water retention agent; the same gradient of water retention agent on vegetation producing flow performed a significant linear correlation between the runoff and the producing time (R2>0.85), comparing the simulated trend line indicated that the curve in natural grassland is greater than the artificial grassland.(3)After water retention agent was applied in different vegetation configurations,its surface sediment yield is largely influenced by amount of retaining agent application. sediment yield decreased with the increased of water retention agent application amount, the linear correlation between sediment yield and sediment yield time was very significant (R2>0.9), with the increasing of rainfall intensity, compared simulation trend line under different water retention agent found that the curve was significantly reduced with the increase amount of agent; impact of applying the same gradient aquasorb amount of vegetation and sediment yield, performed that by applying the same amount of water retention agent, the combination of Agropyron mongolicum and Melilotus suaveolens was more suitable to local prevention and control of soil erosion. When the rainfall intensity was 1.03mm/min, and applied 50g/m2 water retention agent, sediment yield in the combination of Agropyron mongolicum and Melilotus suaveolens was 737.15g which was 62% of it in natural grassland.