Conservation management effects on soil erosion reduction in the Sichuan Basin, China

Water erosion is a serious production problem in the Sichuan province of so uthwest China. Landscapes are topographically complex with slope gradients up to 40% used for crop production. The present recommended procedure for c ontrolling soil erosion has been through terrace construction. However as s lope gradients become greater than 10%, construction rests become prohibiti ve. Prior research hac shown a reduction in water runoff and soil erosion u sing contour management. The objective of this study was to compare the eff ects of two contour management systems with the customary up and downslope tillage and planting (ST) on water runoff soil erosion, and crop production . Experimental sites were established at five locations in Sichuan province . The two contour systems evaluated were a ridge and furrow system establis hed every three years with a no-till planting on the ridge (CTN) for the su mmer crop and a ridge and furrow system established annually (CT) for the s ummer crop. The CTN treatment was more effective than CT in reducing water runoff (P = 0.05) at all locations but only significantly more effective in reducing soil erosion at three of the five rites. The contour management s ystems (CTN and CT) show a significant reduction in water runoff and soil e rosion when compared to ST. An estimated practice (P) factor of 0.31 and 0. 50 was calculated for the CTN and CT treatments. However, two of the five s ites were still experiencing a high rate of soil erosion with contour manag ement indicating that further erosion control measures may be required.