Alley Cropping and Balanced Fertilizer - A New Conservation Technology on Sloping Lands

The effectiveness of combining balanced fertilizer use with alley cropping is being evaluated as a measure to improve farmers’ income by reducing water and soil loss on erosive farmlands in a hilly region of Sichuan province. The project was initiated in 1997 and is jointly managed with the International Board for Soil Research and Management (IBSRAM), but the system of alley cropping was only introduced in 1998. Results from 1999 show that although alley cropping alone reduced the main crop yields by 567 kg/ha, or 6.8 percent, it also reduced soil loss from 2069 to 1025 kg/ha even in a year with less than normal rainfall and increased net income by 145 US$/ha because of the value of one of the alley crops, the day lily.

Table 1 Effect of different treatments on crop yields and reduction of soil losses.




Integration of alley cropping with balanced fertilization applications of 60-120-150 kg N-P₂O₅-K₂O/ha for corn, 60-60-65 kg N-P₂O₅-K₂O/ha for sweet potato, and 150-75-120 kg N-P₂O₅-K₂O/ha for wheat and barley increased crop yields by 480 kg/ha over farmers' practice or 5.4 percent, and improved net income by 261 US$/ha while reducing soil loss by 54 percent. Demonstration fields showed cash crop hedgerows not only offset minor reductions in crop yield but also increased net income by an average of 340 US$/ha. Alley cropping along with balanced fertilization has drawn great interest by nearby farmers. The provincial and local governments have decided to extend this technology to all of Ziyang district and other parts of the province in the coming years. This project may become a national model for profitably reducing soil erosion - the major source of siltation in the Yangtze river that results in flooding and will shorten the life of the Three Gorges dam. This should give national prominence to the essentiality of using the cheaper system of balanced fertilizer and biological barriers rather than expensive mechanical terracing on sloping lands, which represent over 50 percent of China's cultivated land.

A typical alley crop of pear trees and day lily.