呼伦贝尔草原土壤养分与植物群落数量特征的空间异质性

在内蒙古呼伦贝尔克鲁伦河流域的中温型典型草原区,以杭乌拉、额日根、满洲里南、哈克牧场为控制研究样点,分析了典型草原群落在不同土壤水分梯度下土壤养分空间异质性和植物群落的数量变化特征.包括样地优势种盖度、植物种数、地上部现存量和枯枝落叶层现存量等4个群落学量化指标;以及土壤剖面特征、全氮、速效磷和全钾等4个指标作为土壤养分状况的评价参数.结果表明,群落盖度、物种数、地上部现存量、枯枝落叶层现存量与土壤水分梯度表现出一致的变化趋势;不同的草原群落类型,由于维持土壤养分或植被空间格局的匀质化条件的差异,土壤养分的空间异质性呈不同程度的变化趋势,随机性因素所占比例增加,其中土壤全氮、有效磷二者之间表现出明显的正的相关性;种群生物量与植株体积呈现出显著的正的线性相关关系;土壤全N和有效P对群落的地上部现存量起着联合限制作用,枯枝落叶层的现存量与N、P、K含量呈显著正相关.

The Research on the Spatial Heterogeneity of the Soil Nutrient and the Quantitative Properties of Plant Communities in Hulunbeier Steppe

The spatial heterogeneity of the soil nutrients and the quantitative properties of plant communities in the different degraded communities in Hulunbeier steppe were investigate by dominant species in each investigation sample site and typical components in the soil.The results showed that steppe community cover-degree, species number, ground biomass, litter amount and soil moisture had similar trends;there were positive maelative relations between the total N and available P in soil;there were positive linear correlative relations between the species biomass and cubage;the compositive effects of the total N and available P in soil affected the ground biomass of plant communities, and there were positive correlative relations between the litter amount and the contents of N, P and K in soil.