The Study Of Erosion On Red Earth Formed From Quaternary Red Clay

Because China is a country with serious soil and water loss, and bear the greatpressure of population, so soil and water conservation work is responsible.2011is the startyear of "Eleven Five",and Ministry of Water Resources revised "Law of soil and waterconservation".soil and water conservation monitoring is a very important part in thenationwide full implementation of the Water and Soil Conservation Law.This study iscompleted in Tiger hillside surface runoff fields,Taihe County directly under JiangxiProvince.Then I analysis a whole year observation data to draw some soil erosion rules ofthe quaternary red earth formed from red clay.Local erosive rainfall standard11.6mm.Annual rainfall shows weakly bimodaldistribution. Monthly rainfall and monthly erosive rainfall showed the seasonaldistribution,and there is rainy season and dry season.IN March2012to February2013, theperiod of one year, rainfall of April, May, and June accounted for43.6%of annualrainfall,and erosive rainfall accounted for68%. Monthly rainfall and erosive rainfall hasstrong linear relationship.The formula is P0.791P16.111（r²mem0.903）.Few of heavyrain have a significant impact on rainfall kinetic energy and rainfall erosivity.Rainfall andrainfall erosivity was a strong power function relationship, and the formula isR_c=0.2249P_c^1.7721（r²=0.9342）.But power function equation can not explain the relationshipbetween erosive rainfall and rainfall erosivity well. Monthly rainfall erosivity distributionis uneven, and shows obvious double-peak type. The optimal equation form of monthlyrainfall and monthly rainfall erosivity is polynomial, then power. To simplify thecalculation, we use power formula R0.0147P^2.0426（r²m m0.7031）.Rainfall to runoff has the highest correlation coefficient.The best fitting equationtimes of rainfall to runoff is polynomial. Coefficient of determinationr2is between0.67and0.92. Formula coefficient determinationr2of time rainfall and rainfallintensity Q aPbIc dis better fitting than the time rainfall to runoff.The formula ofrainfall,rainfall intensity and vegetation coverage to runoff isA9.853105P^1.987I^0.532（V0.471）^-10.716,and the Coefficient determination is0.741.In this study, the soil erodibility value of quaternary red earth formed from red clayis0.0074t.h.MJ^-1.mm^-1.There is a strong negative correlation on vegetation coverage toerosion.Time rainfall erosivity is most relevant to erosion,then time rainfall and erosiverainfall.The product of rainfall （or erosive rainfall） and rainfall intensity is closely related toerosion.The product of average rainfall and rain intensity to erosion fitting polynomialequation,and valuer2is between0.78and0.88. Formula coefficient determination of time rainfall and rainfall intensity to erosion, A aPbIc d,is higher than0.8.The formula ofrainfall,rainfall intensity and vegetation coverage to erosionisA0.02P2.147I1.3731V4.1691.256,and the Coefficient determination is0.901.Therelationship between monthly rainfall to erosion is very weak,but the monthly erosiverainfall to erosion is good. the value of polynomial functionr2is between0.8to0.87.Through the comparison,we found that grasses grow faster，then it can quickly play abetter role in the early treatment of soil and water conservation.