Application Of WEPP Model In Purple Soil Area And The Comparison Of WEPP Model With USLE Model

Soil erosion prediction model, as a kind of technology tools used for realizing soil erosion processprocess and intensity, controlling land resources development trends, guiding people to use the land resources resonably, has showed its importanceall over the world According to the means and method of building model, the erosion model can be divided into experience statistical model and physical model The experience statistical model is based on the statistical analysis of important factor of erosion process, define the factors of influencing the soil errosion by use of experiment data and statistical technique, the physical model is based on physical process in soil erosion, describe the soil erosion process accordig to the known condition by utilizing the basic principle of correlation branch, predict the erosion capacity in the limited time, which is more accurate than statistical model theoretically And according to the coverage of application of soil errosion model, the model can be divided into slope model and watershed model Now, our country is being in the stage from the experienced model to the physical model, and from slope model to watershed model. In the course of model development in our country and abroad, people got many achievements, but also find many limitations,,The WEPP model is a complex computer program so far and with remarkable superiority compared with the other erosion predication models, which describes the processes that lead to erosion., These processes include infiltration and runoff, soil detachment, transport, and deposition,and plant growth, senescence, and residue decomposition? The model daily calculates the soil water content in multiple layers and plant growth, decomposition. The effects of tillage processes and soil consolidation are also modeled Because the opertion interface of WEPP model is based on English, so it's difficult to popularize the model, the paper has carried on chinesization for 2002 edition on the WEPP model, and has drawn out respectively standard resources and non-standard resources to test, and finally packs to form the plat: WEPP model of chinesization edition.This paper is chiefly divided into four parts, the first study is the relevance of the soil erodibility factor between universal soil loss equation and WEPP model, by ways of application the algorithm of erodibility factor K in EPIC model and the algorithm of rill erodibility factor Kr, interrill erodibility factor Ki in WEPP model, with 35 kinds of soil types data of second general survey in Fujian province serving as the analysis object, discover through compafative analysis that Ki, Kr factor in WEPP model and the K factor in USLE almost have no correlation, for two soil studied layer, the correlation of K factor and Kr factor only is the 0.0154 and 0.0046, K factor and Ki factor only is 0.0107 and 0.0003 The second part is the research son the adaptability of climate generator in Suining purple soil, We utilizate CLIGEN model to imitate respectively the average precipitation monthly, the average highest temperature monthly and the average lowest temperature monthly by using three meteorological data of attaching station in WEPP model(CENTERVILLE, MADISONVILLE and CROCKETT) and replacing the corresponding data using Suining average meteorological data of 15 years, Results show, using the cligen model to imitate, the value and distribution of precipitation and temperature in a year is fitted with actual value, select the meaning absoluted error(MAE) and meaning absoluted percentage error(MAPE) as the index sign of most excellent selection station, finally select CENTERVILLE station as the most excellent station, the meaning absoluted percentage error(MAPE), which use the cligen model to imitate the average precipitation monthly, the average highest temperature monthly and the average lowest temperature monthly are only 7.15%, 7.03% and 6.17% respectivelyThird part is comparison resesrch of CLIGEN and BPCDG in WEPP model, By appling the climate parameters generated by CLIGEN and BPCDG, contrast the influences of two kinds of sub-model with predicted value, we finally find that the result imitated by BPCDG model is superior to the result imitated by CLIGEN, the regression coefficient about predicted and actual of sediment and the runoff by CLIGEN imitate are 0.7609 and 0.6917, and the regression coefficient about predicted and actual of sediment and the runoff by BPCDG imitate are 0.8367 and 0.8175..The fourth part resesrch is the application and comparison of the USLE and WEPP model in Suining group purple soil, the study is conducted in 20° slope plot in Suining soil and water...