关键词: 狼尾草, 植物篱, 水土保持, 土壤养分流失, 坡耕地

Abstract: 【Objective】 The functions of contour grass hedges on sloping croplands were studied, and its cost benefits were analyzed in this research. It is hoped that the results could provide solutions for the serious problems of soil and water loss and agricultural non-point source pollution on sloping croplands in Northern China. 【Method】 The plots with Pennisetum alopecuroide (Pennisetum alopecuroides (Linn.) Spreng) grass hedges and no grass hedges were established. Then the relative parameters, including soil physical properties, soil water and nutrient content, loss of soil and water and soil nutrient, and crop yield, were continuously measured for the plots with grass hedges and no hedges during the period of 2006 to 2010. Finally, the effectiveness of the grass hedges was concluded from the comparative results of the treatments with grass hedges and no hedges. In addition, the cost benefit analysis of grass hedges was also conducted through its costs and effects on crop yield. 【Result】 The soil physical properties were significantly improved by the grass hedges. In the research, the soil bulk density was decreased by 7.0%, and the stable infiltration rate, total soil porosity, soil fine particles (＜0.01 mm) and surface soil water content were increased by 157.1%, 11.0%, 10.8% and 3.5%, respectively, by the grass hedges after 5 years. The soil nutrient content was also greatly increased by the grass hedges, especially for organic matter (12.7%) and available phosphate (24.5%). The grass hedges averagely decreased runoff by 63.2%, soil loss by 77.7%, total nitrogen by 69.4%, nitrate nitrogen by 72.7%, ammonium nitrogen by 57.3%, total phosphate by 54.2% and available phosphate by 62.3%. The grass hedges increased the yield of the crop near the hedges by 21.5%. However, the total crop yield of the plots with grass hedges was slightly decreased because that the grass hedges took up some land area which was originally available for crops. The cost of the grass hedges in this study was 2813 RMB per hectare, which is much cheaper than the other practices such as terrace. 【Conclusion】 Pennisetum grass hedges was proved to be very effective and efficient in reducing the loss of soil and water and agricultural non-point source pollution on sloping croplands. Due to its low cost and well performance, its application could be reasonably extended to the whole area of Northern China.