Analysis of Soil and Water Conservation Function and Economic Benefit of Composite Shrub-Grasslands

From 2005 to 2007,study on composite shrub-grass modes of establishment on the degraded mountain in Yongsheng county in Yunnan province in the Jinsha River hot-arid valley.The results showed that the net profit,economic production-invest ratio and land production relation is shrub+grass+vineshrub+shrub shrubgrass+vinegrass+grassgrassdegraded mountain in planting models.The best planting model is Cajanus cajan + Setaria sphacelata + Festuca arundinacea+ Macroptilium atropurpureum+ Trifolium repens+ Trifolium hybridum.Its net profit,economic production-invest ratio and land production relation are 5 749.8 yuan/(hm2·a),242.8% and 9 469.8 yuan/(hm2·a) respectively.It can improve the physical characteristics of soil,increase soil porosity and infiltration rate of soil,balance the rate capillary porosity and non-capillary porosity,reduce the soil bulk density,lessen soil erosion and control water and soil loss,change soil water utilized,increase soil stability.Therefore,the planting model of Cajanus cajan + Setaria sphacelata + Festuca arundinacea+ Macroptilium atropurpureum+ Trifolium repens+ Trifolium hybridum has great significance in ecological and economic benefits.It is science model of ecological restoration and reconstruction on the degraded mountain in the Jinsha River hot-arid valley.