Effects of contour hedgerows on water and soil conservation, crop productivity and nutrient budget for slope farmland in the Three Gorges Region (TGR) of China

Soil erosion has long been recognized as a major environmental problem in the Three Gorges Region (TGR) where slope farming is commonly practiced but the local topography is hilly. In consideration of the poor socioeconomic position of local farmers, low cost hedgerows had been introduced as a soil conservation measure to the TGR in the late 1980s. A collaborative research programme was initiated by the Chinese University of Hong Kong, the Chinese Academy of Science, the Huazhong Agricultural University, and the Bureau of Soil and Water Conservation of Zigui County to study the potential of adopting hedgerows in the TGR. Six experimental plots (10 m x 2 m, gradient = 25) were constructed at Zigui County, Hubei Province to study effects of hedgerows on erosion, nutrient loss and crop productivity. Results indicated that there were significant relationships between rainfall and runoff, and rainfall and soil loss, respectively. Conventional slope farming could not be considered a sustainable agricultural practice because it resulted in severe erosion and low crop yield. Hedgerows per se seemed not to be effective in reducing soil loss and boosting crop productivity, but performances could be greatly improved when they combined with the use of fertilizers. Current farming and fertilization practices, however, generally did not meet N demands of crops. Results and findings of this paper will contribute towards a technical reference for the promotion and adoption of hedgerows in the TGR.