Sichuan-chongqing Region Of Soil Erodibility Assessment

Evaluation on soil erodibility in Sichuan and Chongqing Hou Dabin (Sichuan Agriculture University, Yaan, Sichuan 625014) Abstract Based on the exploration of soil condition, its physical and chemical nature,its amount and distribution, by applying the erodiable K in USLE and WEPP of the U.S. with the aid of computer and EXCEL software,and by utilizing quantitive analysis and comparison analysis, in this paper the systematic research work is done on the soil erodibility about various types of soil in Sichuan and Chongqing, with the erodiable K calculated, soil erodibility evaluated, soil erodibility graded, and with regression equation of soil erodiable K to average soil and water loss erosion modulus established, and with soil erodibility causes and region characteristics analysed, at last with the effective measures to prevent the soil erosion in Sichuan and Chongqing put forward. The studies show, the soil erodiable K reflects the probability of the soil being eroded, and it is directedly related to the soil physical and chemical nature, to the envioronniental condition and human productive activities; in Sichuan and Chongqing, the soil erodiable K ranges from 0.268 to 0.345, the largest distributed purple soil has highest erodiable K; the erodiable K of the surface soil is lower than that of the inner soil, and the erodiable K of non- cultivated soil is lower than that of cultivated soil; erodibiity of soil with great many gravels in it is lower than that of the soil with a fewer gravels in it. The explored area consists of high eroded bill areas in the middle basin, medium-high eroded soil areas surounding the basin, medium-low eroded soil areas in west Sichuan plateau. The soil in Suining, Neijiang and Nanchong has a high erodibility, and the soil in Aba and Ganzhi has a medium-low erodibility, while the soil in other areas has a high-medium and medium erodibility. In the whole explored area, medium eroded and medium-low eroded soil covers 71.69%, and the high eroded area is larger than the medium-high eroded one. To prevent the soil erosion, measures are to be taken to protect surface soil, increase organic fertilizer, convert slopes fields into ladder fields, carry out the comprehensive soil management, lower or stabilize the erodiable K and reduce the soil and water loss.