垂穗披碱草群落退化演替的植被特性及其与土壤性状的相关性研究

Study on the characteristics of degradation succession of Elymus nutans community and its correlation to soil properties

对垂穗披碱草(Elymus nutans)群落退化演替的植被特性及其与土壤性状的相关性进行了研究。结果表明:在垂穗披碱草群落退化演替过程中,垂穗披碱草的优势度显著下降,物种丰富度和多样性指数显著上升;禾草功能群逐渐衰落,莎草、杂类草功能群渐趋兴盛;演替后期,群落性状趋于稳定。土壤特征主要表现为有机质、全氮、全磷、铵态氮、硝态氮、水分和容重逐渐回升,其中土壤全氮、有机质和铵态氮回升速率尤为显著。垂穗披碱草优势地位的维持主要依赖于种间竞争的最小化和土壤肥力水平的持续稳定,其中氮素水平起主导性作用。补充氮素的最佳时机是垂穗披碱草优势度的峰值期或峰值前期。

The characteristics of degradation succession of Elymus nutans community and its correlation to soil properties were studied.The results showed that with the degradation succession of E.nutans community,the dominance of E.nutans decreased significantly,species richness and species diversities index increased significantly;grass functional group gradually declined,sedges and forbs functional group gradually increased.In late succession stage,the community tended to stable.The main features of the soil properties showed that all indicators gradually showed an increasing trend in addition to soil moisture and total phosphate,and particularly in the late succession stage,the contents of soil organic matter,total N,NH4^＋-N,NO3^-——N,moisture bulky density significantly increased.The dominance persistence of E.nutans depended on the minimization of interspecific competition and sustained soil fertility level,and N played a leading role.The best time to supply N was in peak period or pre-peak period of E.nutans dominance.