放牧与围封对呼伦贝尔针茅草原土壤酶活性及理化性质的影响

Effects of Grazing and Fencing on Soil Enzyme Activity and Soil Physicochemical Properties in Stipa Steppe in Hulunbeier,Inner Mongolia

以呼伦贝尔地带性植被贝加尔针茅草原、大针茅草原和克氏针茅草原为研究对象,研究了放牧和围封对不同类型针茅草原土壤酶活性和理化性质的影响。结果表明,围栏内外草原土壤理化性质差异显著。放牧压力下,土壤容重、pH值均显著升高,土壤含水量、有机质含量显著降低,大针茅草原和克氏针茅草原土壤全氮、全磷含量亦显著下降。各植被类型草原土壤碱性磷酸酶和转化酶放牧样地较围封样地呈现活性增加的趋势,脲酶和过氧化氢酶的活性变化因植被类型不同而各有差异。土壤酶活性与土壤有机质、全氮、速效磷之间具有显著的相关性,可以用来指示草原退化与恢复状况。

Effects of grazing and fencing on soil enzyme activity and physicochemical properties were studied in Stipa baicalensis meadow steppe,Stipa grandis typical steppe,and Stipa krylovii typical steppe in Hulunbeier.The results showed that there were significant differences in soil physicochemical properties inside and outside fence.Under grazing pressure,the soil bulk density and pH value increased markedly,but the content of soil water and soil organic matter decreased significantly,total soil nitrogen content and total phosphorus content were also decreased significantly in S.grandis steppe and S.krylovii steppe.Activity of soil alkaline phosphatase and invertase were higher in the grazing plots than that in the fencing plots,the soil urease and catalase activity varied with different vegetation types.It also showed that there was a significant correlation between soil enzyme activity and soil main fertility factors（organic matter content,total nitrogen,available phosphorus）,and it could be the indicators of the condition of grassland degradation and restoration.