中文摘要：

针对新疆伊犁河谷春秋草场严重退化的现状，通过对退化草场、围栏封育并实施灌溉的草场、单纯围栏的草场和灌溉但不封牧草场样方的对比调查，从地表植物的生物量、植物种类、优质牧草所占比例和草地植物多样性指数等的变化规律和特征方面，探讨了伊犁河谷地区春秋草场退化的原因和恢复措施。结果表明：适当灌溉后草地生物量为1540．5g·m^-2，远高于不灌溉的草地（生物量为188．13g·m^-2），表明干旱是本区草地植被生长一个重要制约因素；而仅改变草地的水分条件，在超载率达123％的大环境下，草场中优质牧草的比例由封育的62．38％下降到未封育的2．08％。因此，适度放牧并辅以灌溉措施是本区天然草场恢复的2个必要条件。

英文摘要：

Aimed at the severe degradation of spring- and autumn pastures in Yili River valley, an investigation was made on these pastures under different managements （fencing, irrigating, and fencing and irrigating ）, and their degradation causes and restoration strategies were dis, cussed from the aspects of plant biomass, species composition, biodiversity, and proportion of high quality grass. The results showed that the plant biomass on the pastures under proper irrigation was 1 540. 5 g · m^-2, while that without irrigation was 188. 13 g · m^-2, indicating that drought was an important factor limiting the vegetation growth. However, it was not enough to only improve the water condition of the pastures under over-grazing. With an overloading rate of 123%, the proportion of high quality grass on the pastures under irrigation decreased from 62. 38% with fencing to 2.08% without fencing. Therefore, moderate grazing supplemented with irrigation could be the prerequisite for the effective restoration of natural pasture in Yili River valley.