Research On Effect Of The Slope Planting Grass To Soil Erosion Process In The Granite Red Soil Slope

The red soil region in southern China is the area where soil erosion is second only to that of the Loess Plateau.Changting County,Fujian Province is a typical representative of the soil erosion areas in southern China.At present,the problem of soil erosion has severely constrained the ecological environment construction and the sustainable economic development in the region.The soil in this study was sampled from the granite red soil in the severely heavily eroded area in Changting County,and artificially simulated rainfall experiment method was used to find the effect of PasPalum wettseinii on the slope erosion process of granite red soil under the conditions of 15°slope and 4 rainfall intensity(0.5,1.0,1.5,2.0 mm/min)in three different growth stages(2 months,4 months,5 months).This study revealed the impact of different grass-planting measures on the erosion process of granite red soil slope in various growth stages to provide a theoretical basis for the soil maintenance work in granite red soil areas in southern China.The main conclusions obtained are as follows:(1)The effect of grass planting on the runoff process of granite red soil slope surface.The runoff process of granite red soil slope is as follows:the runoff volume gradually stabilized after the rapid increase of runoff in the early rainfall and high value.The slope planting grass can prolong the initial runoff time of the slope surface,reduce the peak run-off and total runoff,and the 3 measures can prolong the initial production time over 2min,and the total runoff is lower than the bare slope surface.(2)The effect of grass planting on the process of sand production in granite red soil slope.The regularity of sand production in granite red soil slope is as follows:In the early period of rainfall,the sediment yield decreased rapidly from high value,and then entered a relatively stable state.After planting grass on the slope,the sediment yield of the slope is reduced,the process of sediment production tends to be gentle and the fluctuation of sediment yield is reduced.Compared with nudity,the effect of sand-reducing on grass-planting slope can reach more than 90%,of which,3 measures on the slope surface are near to no sand production.(3)The effect of grass planting on slope erosion and sediment aggregates on granite red soil slope.The grain size composition of eroded sediment can be changed after planting grass on the slope,and the aggregate in the eroded sediment of grass-planting slope is mainly<0.25mm,and the mass ratio can reach more than 80%.(4)During the whole experiment,the erosion process of Masson pine Slope was similar to that of bare slope,when the slope was planted only young Masson pine and the surface was not covered by grass,it could not play an effective soil and water conservation effect in a short time.Soil erosion treatment under Pinus massoniana forest should increase the surface cover and make the stand structure more complete.(5)The efficiency of reducing sediment and reducing sediment is different,and the effect of grass-planting measures is obviously higher than that of reducing the flow.The effect of the grass-planting measures and the benefit of reducing sediment are increasing with the growth of the growing period.To the end of the test,the efficiency of grass-planting measures can reach 40%,and the efficiency of sand reduction can reach 90%,but the effect of reducing sediment and reducing flow in the whole test process of grass-planting measures is the most obvious.Compared with the whole growth process,the effect of 3 measures for reducing flow and sediment reduction in 3 grass planting measures was good,and the benefit of reducing sediment and reducing flow was also increasing.(6)The influence of rainfall intensity and coverage on the erosion process of granite red soil slope is different.The rainfall intensity was positively correlated with the erosion.However,the vegetation coverage was negatively correlated with the erosion.Therefore,the effective planting grass increases the coverage of the surface,which can reduce the amount of erosion.