农牧交错带种植模式与种养模式的能值评价

Emergy analysis was used to analyze two agricultural systems to compare and contrast resource use, environmental impact, and eco-economic benefits. The systems analyzed were traditional cropping system (mode I) and cropping-breeding coupled system (modeⅡ) practiced in Daliangwa Country, Huanxian County of Gansu Province. The results showed: Comparing to mode I,modeⅡhad less cost of production, the fertilizer inputted of modeⅡdecreased 50%,the proportion of nonrenewable industrial energy of modeⅡfell down 32%, the proportion to the organic energy of modeⅡincreased 31%, but the relative economic input of modeⅡhad reduced 30%; The net emergy yield ratio of modeⅡwas 12.65 times than that of mode Ⅰ, the environmental loading ratio of modeⅡdecreased 92%，so the efficiency of resource use was enhanced, environmental impact was dramatically decreased, and emergy sustainable index of modeⅡwas 31.25 times than that of modeⅠ.In this case study the article clarified the mechanism of operating secondary production of grassland agriculture ,which was introduced grass into arable land, can significantly enhance the eco-economic benefits compared to traditional agriculture, which takes the grain as the key link.