【摘要】 为了明确黄土丘陵沟壑区浅层滑坡堆积体植被演替特征及其对土壤养分的影响,本文选取了6个演替年限依次增加的植物群落(猪毛蒿+茭蒿、野菊花+早熟禾、杠柳+猪毛蒿、铁杆蒿+达乌里胡枝子+早熟禾、铁杆蒿+早熟禾和铁杆蒿+达乌里胡枝子),以立地条件类似且未发生滑坡坡面上铁杆蒿群落为对照,通过野外调查和室内试验,研究了物种多样性、植被盖度、地上地下生物量、枯落物蓄积量及土壤养分指标有机质、全氮、全磷含量的变化特征,并对植被特征和土壤养分指标进行相关性分析。结果表明:(1)随着演替年限的增加,Simpson优势度指数D和Margalef丰富度指数M_a呈减小-增加-减小的趋势,Shannon-wiener多样性指数H’和Pielou均匀度指数J_p呈增大-减小-增大的趋势;植被盖度、地上地下生物量、枯落物蓄积量、土壤有机质和全氮含量均呈增加趋势;(2)与对照组相比,演替初期植被盖度差异显著(P <0.05),地上生物量和枯落物蓄积量无明显差异(P> 0.05),地下生物量差异极其显著(P <0.001);(3)表层土壤全氮、有机质含量与植物盖度、地上地下生物量和枯落物蓄积量均呈正相关,全磷含量仅与枯落物蓄积量呈正相关。研究结果深化了黄土丘陵沟壑区植被演替规律及土壤养分对植被恢复响应的认识,为该区浅层滑坡堆积体的治理与生态恢复提供理论指导。更多还原

【Abstract】 In order to demonstrate the vegetation succession characteristics and its effects on soil nutrients,six vegetation communities with different succession ages were selected as research subjects,which were Artemisia scoparia + Artemisia giraldii, mother chrysanthemum + Poa annua, Periploca sepium Bunge + Artemisia scoparia,Artemisia vestita + Lespedeza daurica + Poa annua,Artemisia vestita + Poa annua,and Artemisia vestita+ Lespedeza daurica.As control group,the Artemisia vestita community with similar site conditions located on nearby hillslope without landslides was selected.The variations of vegetation diversity,coverage,aboveground and underground biomass,litter accumulation amount and soil nutrient indices such as organic matter,total nitrogen and phosphorus contents were measured through field investigation and laboratory tests.The correlations between vegetation characteristics and soil nutrient indices were also analyzed.The results showed:(1) Simpson’s D and Margalef’s M_a decreased,then increased,and finally decreased with vegetation succession age.However,Shannonwiener’s H’ and Pielou ’s J_p changed oppositely with succession age.The vegetation coverage,aboveground and underground biomass,litter accumulation amount,soil organic matter and total nitrogen content of different communities increased with succession age.(2) Compared to control group,significant differences were detected in vegetation coverage(P < 0.05) and underground biomass(P < 0.001) at the early succession stage,while no significant difference was found in aboveground biomass and litter accumulation amount.(3) Total nitrogen and organic matter content of top-soil layer(0～10 cm) were positively correlated to vegetation coverage,aboveground and underground biomass,and litter accumulation amount.Total phosphorus was only positively correlated to litter accumulation amount.The results of this study are helpful to understand the properties of vegetation succession and the corresponding soil nutrients response on shallow landslide deposits in Loess Hilly and Gully region,and give theoretical guidance for the management and ecological restoration of shallow landslide deposits in this region.更多还原