内蒙古草地畜牧业可持续发展的生物经济原则研究

草地畜牧业可持续发展的三大生物经济原则为草场不退化原则，最大生物学效率原则和风险，利润权衡原则：（1）草场不退化原则。在冷蒿小禾草退化草原上，暖季期间1．33－2．67羊／hm2的放牧率下可使其发生恢复演替，禾草的比例增大，植物多样性指数和均匀度指数均有所提高，从而达到利用式改良的目的；相反，若继续重牧或过牧，放牧绵羊喜食的植物种类将进一步减少，植物多样性指数也有所降低，最终将趋同于星毛委陵菜退化草原群落，且星毛委陵菜可能是草场沙化荒漠化的最后多年生植物屏障。（2）最大牧草利用效率原则，放牧绵羊的种群生闻，羯头应当年羔育肥出栏，其牧草利用效率不仅提高了4．6倍，且肉用性能可提高2．5倍，同时，应尽量控制羯羊越冬的数量，提高畜群中母羊的处理利润最高（1993年价格），虽然5．33羊／hm2的公顷增重最大，但风险也大，且利润较低。故在综合考虑以上3个原则的基础上，可以通过提高生物学利用效率，即使降低放牧率也不会太大的影响牧民的利益，同时又减轻了生产风险，保护了生态环境，只有这样，才得以使草地畜牧持续发展。

The biological-economical principle on sustainable development of grassland livestock in Inner Mongolia Steppe

With a study of plant community succession on 5 stocking rates,herbage utilizational efficiency and risk\|benefit balance,it is suggested the sustainable development should follow:(1)no degradational principle of rangeland,(2)the maximum herbage utilizational efficiency,(3)the risk\|benefit balance,When stocking rate was no more than 2.67 sheep/hm 2 ,the proportion of grasses and plant biodiversity index and evenness were increased based on Artemisia frigida and short\|grass rangeland.The herbage utilizational efficiency of lamb and total liveweight gain were increased by 4.6 and 2.5 times in comparison with 4.5 year old adult wether.The average liveweight gain per hectare was maximum in the stocking rate of 5.33 sheep/hm 2 ,but its benefit per hectare was less than that of the stocking of 4.00 sheep/hm 2 and risk was larger under 6.0 RMB/kg of buying and selling price in 1993. Overall,he grassland livestock can only develop sustainably based on no degradation of rangeland.And farmer can have more income and lower risk through increase herbage utilizational efficiency and improving management.