石羊河下游绿洲边缘次生草地自然恢复过程及微生物特性的研究

Studuyingon vegetation restoration and soil microbial characteristics on secondary grassland in the downstream of Shiyang River

采用时空替代法,对石羊河流域下游绿洲边缘1~31年退耕区次生草地自然恢复过程中的群落类型及土壤微生物特性（土壤细菌、真菌、放线菌数量及土壤微生物量碳、氮、磷）进行调查、测定及分析。结果表明：石羊河下游绿洲边缘次生草地31年的植被恢复过程中,9个样地的所有样方框共出现植物34种,且随着恢复年限的延长,植物种类逐渐减少,土壤微生物量碳与微生物量磷呈波动下降的趋势,土壤微生物量氮呈先波动式下降后波动式上升最后趋于稳定的趋势;不同年限退耕区次生草地土壤3大类微生物数量均为细菌最高,放线菌次之,真菌最低;植被演替速度比较缓慢;随着恢复年限的延长,物种丰富度指数与多样性指数逐渐减小,均匀度指数逐渐增大,并最终趋于稳定状态;土壤微生物特性总的变化规律与物种丰富度和多样性指数变化规律相一致;土壤微生物量与3大类微生物数量之间存在不同程度的相关性。

The paper studied the vegetation community types and soil microbial characteristics in term of the number of microorganisms and soil microbial biomass C,N,P during the natural recovery process on secondary grassland,which was abandoned cultivated lands in 1~31years in the downstream of Shiyang river.The results indicated that 34 species of plant can be found in the 9investigated samples after abandoned 31 years.Plant speciees number decreased with the vegetation recovery prolong.The soil microbial biomass of C and P trended to be decline.However,the soil microbial biomass of N decreased firstly and then increased,finnaly,it tended to be stabilization.In the abandoned cultivated lands,the number of bacteria was the highest,followed by actinomycetes,fungi number was lowest.Overall,the speed of vegetation succession was relatively slow.The species richness and diversity index decreased with extended abandoned years,while evenness index increased with extended abandoned years and it finally trended to be stable.The general trend of soil microbial declined in a fluctuant way same as that of species richness and diversity index.The correlation result showed that there was a significant positive correlation between the number of microorganisms and soil microbial biomass.