Comparison And Majorization Of The Soil Erosion Estimation Methods For The National Key Area In Liaoning Province

Accurate estimation on the soil erosion condition in certain area is the basis for water and soil conservation in this area and the key of water and soil loss prevention.Presently,the quantity of water and soil loss in certain area cannot be directly measured which generally needs remote sensing,soil loss model,sampling survey,and etc.to be indirectly obtained.In order to improve the precision of soil erosion survey in certain area,the paper researches the representative counties in Liaoning national key controlled region and key prevention region.It individually extracts soil erosion factors and calculates soil erosion amounts under three factor model and six factor model?USLE?.Also,the paper carries out contrastive analysis on the different calculated results under different soil erosion models against the measured data in runoff plot.It optimizes the calculation by genetic algorithm to find out estimated method appropriate for soil erosion in Liaoning key prevention area.The main conclusions are as below:?1?In three factor model,from the result of land use factor,the land use type of Xi feng and Chao yang is mainly of forest land and Kuandian is forest land and grassland;from the result of vegetation coverage factor,large areas in Xi feng and Kuan dian are in high coverage and medium to high coverage while large areas in Chao yang are in high coverage,medium to high coverage and medium coverage;from the result of gradient factor,gradients in Xi feng and Chao yang are mainly below 25° and above 8° while Kuan dian are mainly above 15°.In USLE,the R factor in Xi feng and Chao yang is lower while that in Kuan dian is higher;the largest value of K factor in each county is mainly in forest land and dry land;the maximum values of LS factor in research area are mainly in forest land;the maximum values of C factor in research areas are mainly in other land and dry land;the maximum values of P factor is 1.?2?Calculated in three factor model,the soil erosion area in Xi feng county is 1051.71 km²,39.89%of Xi feng total area,which are mainly of mild erosion;the soil erosion area in Chao yang county is 1629.98km²,43.36%of Chao yang total area,which are mainly of medium and intense erosion;the soil erosion area in Kuan dian county is 1546.78 km²,25.29%of Kuan dian total area,which are mainly of mild and medium erosion.?3?Calculated in USLE,the soil erosion area in Xi feng county is 616.40km²,22.96%of Xi feng total area,which are mainly of mild and medium erosion;the soil erosion area in Chao yang county is 1875.76km²,50.99%of Chao yang total area,which are mainly of mild and medium erosion;the soil erosion area in Kuan dian county is 2685.69km²,43.92%of Kuan dian total area,which are mainly of mild and intense erosion.The average soil erosion modulus in Xi feng is 1469.93t/km².a,the average soil erosion modulus in Chao yang is 1496.84t/km²·a,the average soil erosion modulus in Kuan dian is 1667.29t/km²·a,mainly of medium erosion.?4?Compared the soil erosion intensity and modulus,the results calculated in six factor soil erosion model in controlled region?Chao yang and Xi feng?are more approached to the measured data which are mainly of mild and medium.While,the results calculated in three factor soil erosion model in prevention region?Kuan dian?are more approached to the measured data which are mainly of mild and medium.After comparison and analysis of the factor extraction and influence of each factor on model estimation to the measured data,USLE is more appropriate for controlled region while three factor model is more appropriate for prevention area.?5?Comparing the soil erosion estimated value?Xi feng and Chao yang?calculated in USLE with the measured data in runoff plot in research area,the paper builds difference function between model estimated value and measured data in Liaoning representative controlled region.Y=1×10^-4X₁+0.666 X₂ + 0.0896 X₃ + 0.0001 X₄-2.6864 Xs.The output value of optimization function shows that the factor of soil and water conservation measure has largest influence on the measured data and model estimated value.Meanwhile,the difference between measured data in research area and soil erosion estimated value calculated in USLE has been declined to 8.57%from 23.48%after optimizing on soil erosion model.