Soil Erodibility Research And Application Of Low Hill And Mound Soil In Rocky Mountain Area Of Northern Huai River

One of the important factors that lead to the improvement or aggravation of soil erosion is the reasonable Soil erosion is the main cause of a series of ecological crisis,such us soil quality degradation,eutrophication of water body and so on.It is a major environmental problem facing the global terrestrial ecosystem.Ganyu district is the key administration areas of soil and water loss of northern Rocky Mountain area in Jiangsu Province.Soil erosion model can well reflect the process of soil erosion and quantitative evaluation of environmental effects in Ganyu district.Soil and water conservation measures can effectively mitigate soil erosion in Ganyu district based on soil erosion model.Soil erodibility factor K is an important parameter for soil erosion model,and accurate estimation of K value is the basis and prerequisite for establishing soil erosion model.It is also an important basis for quantitative evaluation of soil erosion.The study of soil erodibility and the accurate estimation of K value is of great significance for the quantitative evaluation of soil erosion,the establishment of soil erosion model and the prevention and control of soil erosion.In this paper,the typical low hilly area of Huaibei is selected as the study area.Based on measured data of soil erodibility K value in Heilin runoff plot,this study revised the EPIC formula with the help of ¹³⁷Cs isotope tracer technique,analyzed the spatial distribution of soil erodibility K value in Ganyu district and studied the correlation between soil erodibility K value and soil particle.At the same time,combined with meteorological,soil,terrain and remote sensing and other multi-source data in Ganyu district,this study quantitatively evaluated the spatial characteristics of soil erosion in Ganyu district in 2015 with soil erosion model.Finally,the relationship between soil erosion and different elevation,slope and land use types was revealed with GIS spatial analysis and statistical function.The main research results are as follows:（1）The measured and estimated values of soil erodibility K value:The K value of yellow sand soil（brown tide subspecies）measured by runoff plot was 0.035.The average value of K measured by ¹³⁷Cs isotope tracer technique and the EPIC formula in the same kind of soil were calculated.The average K value of loess（brown tide subspecies）were 0.036 and 0.041.The average K value of patina soil（brown earth subspecies）were 0.037 and 0.039.The average K value of Baijiang soil（brown earth subspecies）were 0.053 and 0.034.The average K value of sandy soil（coarse brown soil）were 0.046 and 0.045.According to the modified EPIC formula,the average K value of the soil in Ganyu area was estimated: 0.034 of the brown soil type was the same as that of the fluvo aquic soil,and that of the fluvo aquic soil was the same as that of the 0.037,and the black soil of the sandy soil was the same as that of the saline soil in the area,which was as follows: 0.039（2）Revision and verification of EPIC model:By means of correlation analysis and regression analysis of the measured value of ¹³⁷Cs and the estimated value of EPIC formula,the linear regression equation is established: y=0.701x+0.0089,R2=0.66。Modified EPIC formula:（3）Based on revised EPIC model,K value and characteristics of soil erodibility in Ganyu district were obtained:Correlation analysis between soil erodibility K value and surface soil particle characteristics were carried out.The results showed that there was a significant negative correlation between sand content and K value of soil erosion.There was a significant positive correlation between silt content and K value of soil erosion,and there was a negative correlation between soil organic carbon content and K value of soil erosion.（4）Spatial distribution characteristics of soil erosion in Ganyu District:The average erosion modulus of Ganyu district were 859.2 t/km²·a,mainly with micro and mild erosion.The area of mild erosion was 393.36km²,accounting for 10.17% of the total area.The area of moderate erosion was 74.4km²,accounting for 5.38% of the total area.The area of strong erosion was 28.03 km²,accounting for 2.03% of the total area.The area of extremely strong erosion was 23.95km²,accounting for 1.73% of the total area.The area of severe erosion was 14.26km²,accounting for 1.03% of the total area.The results showed that the 98% of soil erosion in Ganyu district was from farmland and garden plot by superposing soil erosion with land use types.Vertical pattern of soil erosion: Superposed soil erosion intensity distribution with elevation grade and slope grade,no matter in plain area,hilly area or low mountain area,micro erosion was always the main body.With the increase of elevation,the area of soil erosion intensity of the same grade decreased.The soil erosion intensity increased with the increase of slope.The soil erosion area decreased after the slope was greater than 25°.