黄土丘陵区铁杆蒿群落植被特性及土壤养分特征研究

Study on vegetation and soil nutrient characters of Artemisia sacrorum communities in hilly-gully region of the loess plateau

对黄土丘陵区森林草原带铁杆蒿种群演替变化中不同恢复年限的群落植被特征和土壤养分进行分析，结果表明，随着植被恢复年限增加，群落物种组成不断变化，群落总盖度、地上与地下生物量逐渐增加，群落多样性指数先增加后减小再趋于稳定，丰富度指数缓慢升高但变幅不大，而均匀度指数与多样性、丰富度指数变化趋势相反；土壤有机碳、全氮、全磷、碱解氮和速效钾增加且上层土壤养分恢复较下层块。群落植被因子与表层土壤养分相关分析表明，植物群落总盖度、铁杆蒿盖度、群落物种多样性指数、群落地上与地下生物量与表层土壤（0～20cm）养分间均呈现正相关关系，铁杆蒿盖度与群落总盖度、表层土壤有机碳、碱解氮间呈显著正相关，与群落地下生物量和丰富度指数（Ma）间的相关性达到极显著水平。群落地上与地下生物量、有机碳和碱解氮间存在显著正相关。群落地下生物量与Ma间存在显著正相关，与土壤有机质、碱解氮达到极显著水平。这说明群落生物量可以在土壤养分因素的作用下得以显著恢复，土地生产力的提高又促进演替的进行。

This study analyzed the sacrorum communities, which cha cession stages m and underground the bio vege nged tation characteristics, species biodiversity and soil nutrients of Artemisia from components to the dominants of communities during different suc loess-hilly region. There was a significant difference in community coverage, aboveground mass in the succession series. The index of community biodiversity changed from high to low then became stable. The index of richness increased gradually with succession time. However, the even ness index decreased with th time and the upper layer soil e restoration years. In general, soil nutrient contents increased with restoration nutrients improved faster than those lations in total coverage of the communities, coverage of A. of the lower layer. There were positive corresacrorum, community ＇ biodiversity indices, aboveground biomass, underground biomass and upper layer （0-20 cm） soil nutrients. There were significant positive correlations between coverage of A. sacrorum communities, total coverage, upper layer soil organic carbon, and available nitrogen. Extremely significant positive correlations occurred in A. sacrorum communities, underground biomass and richness index （Ma）. There were significant positive correlations between underground biomass and Ma, also extremely significant positive correlations between underground biomass, soil organic carbon and available nitrogen. The results suggest that community biomass can be recovered under better soil nutrients conditions and enhanced soil production could promote vegetation succession. The natural restoration of vegetation is an important approach to ecological restoration.