中文摘要：

以内蒙古呼伦贝尔的克氏针茅（ Stipa krylovii）典型草原作为研究对象，研究轻、中、重三种放牧强度对草地土壤养分和土壤酶活性的影响和相互作用，旨在为克氏针茅草原生态系统的保护、恢复及重建提供科学依据。结果表明：土壤养分含量显著降低（P〈0.01）；随着放牧强度的增加，过氧化氢酶和蔗糖酶均显著降低（P〈0.05），而对脱氢酶和磷酸酶无显著差异（P〉0.05）。相关分析表明，土壤酶活性与土壤养分含量密切相关，放牧干扰条件下土壤中有效磷与土壤脲酶、过氧化氢酶、蔗糖酶和磷酸酶粒脲酶活性呈显著相关（P〈0.05）。

英文摘要：

Taking Stipa krylovii typical steppe in Hulunbuir of Inner Mongolia as test objects, the effects of different grazing intensities on soil enzyme activities and chemical properties were stud-ied, aiming to provide scientific basis for protection, restoration and reconstruction of Stipa kry-lovii. The results showed the soil nutrients reduced significantly （P〈0. 01） along with the in-creasing of grazing intensity. The activities of soil catalase and sucrase enzymes all reduced sig-nificantly （P〈0. 05）with the increasing of grazing intensity, but there was no significant differ-ence between soil phosphatase and dehydrogenase enzyme activities （ P〉0 . 05 ） . The results of correlation analysis showed that soil enzyme activities was closely related to soil nutrient con-tents, and soil available phosphorus content and soil urease, catalase, sucrase and phosphatase activities in grazing disturbance conditions were significantly correlated （ P 〈0 . 05 ） .