|Liu, Gangcia - INST OF MT HAZARDS & ENV|
|Zhang, Xianwan - INST OF MT HAZARDS & ENV|
Submitted to: Journal of Soil and Water Conservation Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 6, 2000
Publication Date: N/A
Interpretive Summary: Water runoff and soil erosion is a serious crop production problem in the Sichuan Province of southwest China. The present recommended technique for erosion control is terrace construction. However as slope gradients become steeper than 10%, the cost of terrace construction becomes prohibitive. It was the purpose of this study to evaluate the effectiveness of contour management systems on erosion control and crop production. Two contour systems were established at five locations in Sichuan Province. The two contour systems evaluated were a ridge and furrow system established every three years with a no-till planting for the summer crop and and an annually established ridge and furrow for the summer crop. Water runoff and soil erosion occurs mostly during the summer period. Results from this study showed that contour management reduced water runoff and soil erosion and increased crop yields with the no-till planting on established ridges being gmore effective than the annually established ridges. Both contour systems were better than the customary up and downslope tillage and planting. However, water runoff and soil erosion amounts were exceedingly high with the contour management systems at two of the five sites, indicating that additional research is required to develop adequate soil protection. These results present alternate methods for crop producers to control soil erosion and increase yields in topographically complex areas with steep slope gradients where investment funds for terrace development are limited.
Technical Abstract: Water erosion is a serious production problem in the Sichuan province of southwest China. Landscapes are topographically complex with slope gradients up to 40% being used for crop production. The present recommended procedure for controlling soil erosion has been through terrace construction. However as slope gradients become greater than 10%, construction cost becomes prohibitive. Prior research has shown a reductio in water runoff and soil erosion using contour management. The objective of this study was to compare the effects 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 established every three years with a no-till planting (CTN) for the summer crop, the prime erosion period, and dan annually established ridge and furrow (CT) for the summer crop. Results from these comparisons show that contour management significantly reduced water runoff and soil erosion. The CTN 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 one of the five site. The contour management systems (CTN and CT) show a significant reduction in water runoff and soil erosion 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 sites were still experiencing soil erosion at an unacceptably high level with contour management, indicating that further erosion control measures may be necessary to control soil erosion, depending on site characteristics.