Abstract: The degradation of grasslands leads to the decline in soil fertility,the reduction in forage yield,and impacts the ecosystem services of grasslands. This study systematically evaluated the effects of fertilization on productivity and community structure of degraded Leymus chinensis and Stipa grandis grasslands. Seven types of fertilizers (urea,microbial agent,vermicompost,se-rich foliar fertilizer,sheep manure fertilizer,Selenium-rich organic fertilizer,humic acid organic fertilizer) and four fertilization levels (control,low level,medium level,high level) were applied. The results indicated that both organic and foliar fertilizers significantly improved above-ground and below-ground biomass of grassland (P<0.05),with no significant impact on species diversity. Although urea application significantly increased grassland biomass (P<0.05),it reduced species diversity (P<0.05). Comprehensive evaluation based on principal component analysis revealed that se-rich foliar fertilizer had the best ameliorative effect on degraded Leymus chinensis grasslands,and the optimal fertilizer concentration was medium. This study provided a theoretical basis for the restoration of moderately degraded grassland by fertilization.

Key words: Degraded grassland, Organic fertilizer, Foliar fertilizer, Fertilizer type, Comprehensive assessment

摘要： 草地退化可降低土壤肥力，减少牧草产量，从而影响草地的生态系统服务功能。本研究对羊草(Leymus chinensis)+大针茅(Stipa grandis)中度退化草地进行7种肥料种类(尿素、微生物菌剂、蚯蚓叶面肥、富硒叶面肥、羊粪发酵有机肥、富硒有机肥、腐殖酸有机肥)和4种施肥水平(对照、低浓度、中浓度、高浓度)的施肥研究，系统评价了施肥对退化草地植被生产力和群落结构的影响，发现有机肥和叶面肥均可以显著改善草地的地上和地下生物量(P<0.05)，对群落的物种多样性无显著影响。施用尿素虽然可以显著提高草地生物量(P<0.05)，但降低了物种多样性(P<0.05)。基于主成分分析的综合评价表明，富硒叶面肥对中度退化草地的改良效果最好，最佳施肥浓度为中等浓度水平。本研究为中度退化草地施肥恢复提供了一定的理论依据。

关键词: 退化草地, 有机肥, 叶面肥, 肥料类型, 综合评价