中文摘要：

在青藏高原高寒地区选取高寒草甸常见禾本科牧草垂穗披碱草、中华羊茅和羊茅建植多年生人工草地进行试验.试验设计为施肥和对照,共4个密度,7种播种组合,连续3年调查人工草地的地上生物量以及杂草丰富度和杂草生物量,分析施肥对草地生产力和稳定性的影响.结果表明：施肥可以有效补充土壤对植物的养分供给,使牧草获得较高的生物量,提高草地生产力.施肥使人工草地生产力连续2年增加,第3年的增加幅度变小.随着草地建植时间的增加,施肥能有效抑制杂草的入侵和生长,降低人工草地的杂草丰富度和杂草生物量,维护人工草地的生产力和稳定性,有利于青藏高原高寒地区的经济发展和生态环境建设.

英文摘要：

The experiment was carried out in cultivated grassland on three kinds of perennial grasses：Elymus nutans,Festuca sinensis,and Festuca ovina which are distributed widely in the east Qinghai-Tibetan plateau. There were four densities and seven sow combinations in the experiment to study the effects of fertilization on biomass,weed abundance and weed biomass of cultivated grassland along three growing seasons.The results showed that fertilization could replenish nutrient supply and increase cultivated grassland productivity in two years after the cultivated grassland was established.However,the increased extent of productivity in cultivated grassland decreased in the third year.Fertilization could resist weed invasion and reduce weed biomass and weed abundance in the cultivated grassland.Fertilization not only increased productivity but also the resistance to weed growth,thus making itself a good choice to improve rangeland,which will benefit both local economic development and environmental protection.