高山嵩草草甸初级生产力、多样性与土壤因子的关系

摘要

为了揭示高寒草甸初级生产力与土壤因子及多样性指数的关系，本文选择青藏高原三江源区具有代表性的高山嵩草矮嵩草草地型、高山嵩草杂类草草地型和高山嵩草圆穗蓼草地型，进行植物多样性、生产力及土壤养分的分析研究。结果表明：不同类型高山嵩草草甸生物量、群落多样性、土壤理化性质都存在显著差异（P ＜0．05），其中高山嵩草圆穗蓼草地生产力最高，物种数最多，土壤营养成分含量最高。相关性分析表明：地上生物量及优良牧草生物量与土壤理化性质呈显著相关（P ＜0．05），优良牧草生物量与土壤有机质呈极显著正相关（P ＜0．01）。物种数的多寡与土壤养分呈显著相关（P ＜0．05），而群落结构的均匀度及多样性是与植物都需要的大量元素钾呈正相关的（P ＜0．01）。优势物种的竞争能力是通过土壤的有限养分（速效磷）体现的，两者呈显著正相关（P ＜0．05），因而地上生物量及优良牧草生物量与速效磷呈极显著正相关（P ＜0．01）。而矿物氮（包含碱解氮）对丰富度指数、初级生产力有不可替代的作用。%The relationships among primary productivity,soil factors and plant diversity in alpine meadows were investigated by analyzing plant community diversity,productivity and soil nutrients of three grassland types in the Three Rivers District,Kobresia pygmaea +Kobresia humilis ,Kobresia pygmaea +forbs and Ko-bresia pygmaeaPolygonum macrophyllum meadow.The biomass,community diversity and soil physical and chemical properties of the different alpine meadows types differed significantly (P <0.05).The Kobresia pyg-maea +P .macrophyllum meadow had the highest productivity,number of species and soil nutrient content. Correlation analysis showed that forage biomass and soil physical-chemical properties (P <0.05)and soil or-ganic matter (P <0.01)were significantly positively correlated.The number of plant species present was also correlated with soil nutrients (P <0.01),while uniformity and diversity of community structure were positive-ly correlated (P <0.01)with soil potassium content.The competitive advantage of dominant species was asso-ciated with tolerance of low fertility(P <0.05),particularly phosphorus.Aboveground biomass and forage bio-mass and available phosphorus were significantly positively correlated (P <0.01 ).Nitrogen was associated with species richness and productivity.