等高固氮植物篱技术在坡耕地可持续耕作中的应用

Contour Hedgerow Intercropping Technology and Its Application in the Sustainable Management of Sloping Agricultural Lands in the Mountains

等高固氮植物篱技术是利用固氮植物能够固氮、生长快和具多用途的特点 ,在坡耕地上建立高密度植物篱。通过枝叶还田及腐根和枯枝落叶 ,有效改善土壤肥力、团粒结构及水分渗透率 ,加上植物篱的机械阻挡 ,降低地表径流 5 0 %～ 70 % ,减少土壤侵蚀 97%～ 99% ,土壤全氮含量增加 6 5 %～ 10 3% ,有机质含量增加达 2 5 %～ 35 % ,农作物增产达 30 %～ 6 0 %。该技术具有投入低、操作简便、实用性强、效果显著、效益多样的特点。该技术综合地解决了山区坡耕地水土保持和土壤培肥的问题和用地、养地的矛盾 ,可实现坡耕地的可持续耕作利用 。

In the past five decades the ever growing human population and declining cropland in China have made the livelihood in the mountains more difficult and forced expansion of farming onto more steep land and clearing of forests and other types of vegetation, causing severe soil erosion. The severe soil erosion and its resultant effects have impeded sustainable development in China. The contour hedgerow intercropping technology is developed to respond to these problems on the basis of the unique features of nitrogen fixing plants, including the ability to fix nitrogen from the atmosphere, the ability to improve soil fertility, the capability of growing fast and the capability of providing multiple benefits. Perennial woody nitrogen fixing plants are planted very thickly along the contour lines on sloping farming land as hedgerows with an inter hedgerow distance of 3～6 meters. The thickly planted hedgerows of nitrogen fixing plants are pruned periodically to avoid shading companion crops and to provide materials to improve soil fertility, water infiltration rate, and soil structure. The properly established and managed contour hedgerows can reduce the surface runoff by 50～70 per cent, and soil loss by 97～99 per cent. Addition of the hedgerow prunnings together with decomposition of roots and litter can improve considerably soil fertility, water infiltration rate, and soil physical structure, leading to the increase in the content of nitrogen and organic matter by 65%～103% and 25%～35%, respectively. The improved soil fertility and soil moisture condition enhanced the crop yield by 30%～60%. The contour hedgerow intercropping technology is low in cost, easy to adopt, effective, and multipurpose, and makes sustainable development in the mountains possible. It should be diffused widely in the mountainous region of China and it is believed that the wide extension would contribute greatly to sustainable agricultural development and environmental protection in the mountains.