Abstract: In order to understand the plant community species diversity and plant above-ground biomass in response to bio-organic fertilizer in natural degraded grasslands (slightly,severely degraded),we carried out this study in northwest plateau,Sichuan province. In a completely randomized trial,we determined the effects of bio-organic fertilizer on natural degradation of grassland plant community species;plant height,coverage and frequency,the ground biomass and forage quality;plant community and its production performance. The results showed that organic fertilizereffectively improved plant height and coverage,promoted the number of species in grassland plant community,also improved the diversity and stability of grassland plant community structure. Bio-organic fertilizer increased the herbage yield of light degraded grassland by 2.05 times (P < 0.01),increased crude protein content and total phosphorus content by 46.32% and 69.89% respectively. Moreover,bio-organic fertilizer increased the grass yield,crude protein and crude fat contents of severely degraded grassland (desertification land) by 1.83 times (P < 0.01),63.23% and 22.73%,respectively,and significantly reduced the content of NDF and ADF (P < 0.05),and improved the forage palatability,and digestibility.

Key words: Biological organic fertilizer, Degraded grassland management, Biodiversity, Forage yield, Herbage quality

摘要： 为了解天然退化草地植物群落物种多样性和地上生物量对生物有机肥的响应，本试验以川西北天然退化草地（轻度退化、重度退化）为研究对象，采用完全随机试验设计，通过测定植物群落物种数、植株高度、盖度和频度以及地上生物量和牧草品质，探究生物有机肥对退化草地物种多样性及其生产性能的影响。结果表明：生物有机肥可以提高植株高度、盖度，增加草地植物群落中物种数量，改善草地植物群落结构和提高群落稳定性；有机肥使轻度退化草地牧草产量提高了2.05倍（P<0.01）、粗蛋白含量和总磷含量比对照分别增加46.32%和69.89%；使重度退化草地（沙化地）牧草产量提高1.83倍（P<0.01），粗蛋白含量和粗脂肪含量分别比对照提高63.23%和22.73%，且在两种退化草地中均显著降低了中性洗涤纤维和酸性洗涤纤维的含量（P<0.05），提高了牧草的适口性和消化率。

关键词: 生物有机肥, 退化草地治理, 生物多样性, 牧草产量, 牧草品质