放牧对植物群落特征和土壤微生物及酶活性的影响

目的]探讨放牧对羊草群落和贝加尔针茅群落的影响,为草原土壤的保护和草原自然保护区建设提供科学依据。方法]以呼伦贝尔草甸草原为样地,采用野外调查和实验室分析相结合的方法。结果]在放牧干扰下,以羊草为建群种的群落所受的影响比贝加尔针茅群落小,植物群落盖度、高度和Simpson指数明显高于贝加尔针茅群,物种多样性更丰富,生长情况相对更好。羊草草原土壤全氮、全磷和有机质含量高于贝加尔针茅草原土壤。各放牧区土壤微生物数量均表现为:细菌放线菌真菌;垂直分布为0—10cm10—20cm;土壤脲酶、过氧化氢酶、转化酶活性、全N,全P和有机质等0—10cm土层的均高于10—20cm。相关分析表明,植物群落α多样性与土壤微生物数量、土壤酶活性、全N,全P和有机质等呈显著正相关。结论]适度放牧有助于提高草甸草原羊草群落和贝加尔针茅群落α多样性、土壤微生物数量和土壤酶活性。两个群落相比较,羊草群落更适合放牧。

Influences of Grazing on Plant Community Characteristics, Soil Microorganism and Soil Enzyme Activity

Objective] The objective of this study is to explore the effects of grazing on the Leymus chinensis and Stipa baicalensis communities under the grazing disturbance in Hulunbeier meadow steppe ,in order to provide the scientific basis for the protection of grassland soil and construction of grassland nature reserve . Methods] Taking the Hulunbuir meadow steppe as sample plot ,the field investigation was conducted and laboratory analysis was used .Results] The influences of grazing on L .chinensis communities were less than that on Stipa baicalensis communities .Under the disturbance of grazing ,coverage ,height and the Simpson index of plant community was significantly higher ,the species diversity was greater and the growth situation was relatively better in L .chinensis communities .The soil total nitrogen ,soil total phosphorus and soil organic matter contents in L .chinensis was higher than that in S .baicalensis .The amount of microor‐ganisms in two grazing areas showed the same changing trend as :bacteria>actinomyces>fungi .The number of microbes in 0—10 cm soil layer was higher than that in 10—20 cm soil layer .Similarly ,soil urease ,cata‐lase ,invertase in 0—10 cm was greater than that in 10—20 cm soil layer .Correlation analysis indicated that theα diversity of plant community were positively related to soil microorganisms ,soil enzyme activities ,soil total nitrogen ,soil total phosphorus and soil organic matter .Conclusion] Moderate grazing could improve community α diversity ,soil microbial quantity and soil enzyme activity of L . chinensis and S . baicalensis communities .For two communities ,L .chinensis is more suitable for grazing than S .baicalensis .