子午岭植被自然演替中植物多样性变化及其与土壤理化性质的关系

Plant Species Diversity and the Relation with Soil Properties in Natural Succession Process in Ziwuling Area

在野外样方调查和室内实验分析的基础上，采用相关性分析和多元逐步回归方法，分析了黄土高原子午岭地区不同演替阶段群落物种多样性、土壤理化特性以及二者的相互关系。结果表明：群落物种多样性随演替进展呈增长趋势，但其增长并非完全线性，主要表现为草本群落演替阶段物种多样性指数高于灌木演替阶段。0～20cm和20-40cm土层土壤的全氮、有效氮和有机质等土壤养分指标随着植被演替不断增大。在演替过程中，土壤含水量变化虽有波动，但总体上升，土壤容重波动下降，说明演替过程中土壤环境在不断得到改善。40～60cm土层土壤理化性质变化未表现出一定规律，说明其与植被演替没有必然联系。物种多样性指数与土壤因子的相关性分析表明，群落演替过程中物种多样性变化与土壤因子存在一定相关性，其中0～20cm土层土壤的全氮和有机质与物种的多样性指数呈显著正相关。随着土层加深，物种多样性对土壤理化性质影响表现出减弱趋势。

Base on the survey of community plots and laboratory analysis, we studied the plant species diversity, soil properties and their relationship in different successional stages with correlation analysis and multiple regression methods in Ziwuling area on Loess Plateau. The results showed that the trend of the species diversity with succession is not completely linear, because the species diversity index is higher in herbaceous successional stage than that of the shrub＇ s. Soil total nitrogen, available nitrogen and soil organic matter of the 0-20 cm and 20-40 cm layers increase with the vegetation succession. The soil water content is increasing with a little fluctuation and the soil bulk density declined with some fluctuation. It indicated that the soil environment is improved with the vegetation succession. The changes of 40 - 60 cm soil layers are not followed with some rules,which showed there is no causal links with the succession of vegetation. The correlation analysis between species diversity and soil factors showed that there are certain correlations between them in the process of evolution,and the soil nitrogen and soil organic matter of 0-20 cm layer are positive significantly correlated with the species diversity index. The effects of species diversity on the soil properties are weakening with the increasing soil depth.