中文摘要：

以呼伦贝尔5种不同草地类型（线叶菊草原、贝加尔针茅草原、羊草草原、大针茅草原、克氏针茅草原）为研究对象,分析了不同草地类型土壤理化性状、土壤微生物数量、土壤微生物量、土壤酶活性的变化特征及其相互关系。研究表明,各类菌群数量分布在5种草地中均为细菌〉放线菌〉真菌,但不同菌群数量及区系组成在各草地类型间均存在显著差异（P〈0.05）。细菌数量在5种草地中依次为：羊草〉贝加尔针茅〉克氏针茅〉线叶菊〉大针茅,真菌数量依次为：线叶菊〉克氏针茅〉羊草〉贝加尔针茅〉大针茅,放线菌数量依次为：克氏针茅〉羊草〉线叶菊〉贝加尔针茅〉大针茅。土壤微生物量碳、氮（SMBC、SMBN）在不同草地类型间差异显著（P〈0.05）,线叶菊草原土壤微生物量碳、氮均显著高于其他草地类型（P〈0.05）,其中大针茅草原、羊草草原土壤微生物量碳、氮均较低。研究还表明,各草地类型土壤酶活性的垂直分布均表现为表层土壤（0～10cm）酶活性大于下层土壤（10～20cm）酶活性,不同草地类型间土壤酶活性亦存在显著差异（P〈0.05）,线叶菊草原土壤过氧化氢酶和转化酶活性均显著高于贝加尔针茅草原和大针茅草原;土壤脲酶活性以克氏针茅草原最高,且与线叶菊草原、贝加尔针茅草原和大针茅草原差异显著;而土壤磷酸酶活性则为羊草草原显著高于其他样地。相关分析结果表明,不同草地类型土壤微生物数量、土壤微生物量、土壤酶活性、土壤理化性状之间均存在相关性,从回归分析得出的2个方程可知,土壤微生物量碳随着土壤含水量、细菌数量的增加而增加,随着土壤磷酸酶活性的增加而降低;土壤微生物量氮则随着土壤过氧化氢酶活性的增加而增加,而随着土壤磷酸酶活性与土壤容重的增加而降低。

英文摘要：

In this study,5different types of grassland（Filifolium sibiricumsteppe,Stipa baicalensis steppe,Leymus chinensis steppe,Stipagrandis steppe,Stipa kryrowi steppe）in Hulunbeier were selected as the research object to analyze the variation of the soil physicochemical characteristics,soil microorganism,soil microbial biomass,soil enzyme activity and the inter-relationship among them.The results showed that the number of microorganisms in different types of grassland were in the same changing trends：bacteria〉actinomycetes〉 fungi,but the number of each microorganism and composition reduced significantly（P〈0.05）.The bacteria number in 5different types of glasslands was 〉L.chinensis steppe〉S.baicalensis steppeS.kryrowi steppe F.sibiricumsteppe〉S.grandis steppe,the fungi number was〉 S.kryrowi steppe〉L.chinensis steppe F.sibiricumsteppe〉S.baicalensis steppe〉S.grandis steppe,the actinomycetes number was F.sibiricum steppe〉S.kryrowi steppe〉L.chinensis steppe〉S.baicalensis steppe〉S.grandis steppe.Soil microbial biomass C,N（SMBC,SMBN）reduced significantly（P〈0.05）in different grasslands.The microbial biomass carbon and nitrogen in F.sibiricumsteppe soil were significantly higher than others（P〈0.05）,soil microbial biomass C and N in S.grandis steppe and L.chinensis steppe were lower.Results also showed that soil activitiey reduced significantly（P〈0.05）in different grasslands with 0-10cm higher than 0-20cm in the vertical distribution.Soil activitoes of catalase and invertase activities of F.sibiricumsteppe were significantliy higher than S.grandis steppe,S.baicalensis steppe;Soil urease activity of S.kryrowi steppe was the highest and significantly different fromS.grandis steppe,F.sibiricumsteppe,soil phosphatase activity in L.chinensis steppe was the highest and significantly different from others.Correlation analysis indicated that soil microbe quantity,soil microbial biomass,soil enzyme activity and soil physicochemical characteristics in different grasslands had dif