松嫩盐碱草地西部的植物群落特征与土壤因子动态关系分析

应用逐步回归法，分析了5~9月松嫩盐碱草地植物群落的生物量、丰富度、多样性和均匀度与同月土壤因子间的关系。松嫩盐碱草地植物群落特征受若干土壤因子的共同影响，不同月份影响因子的变化较复杂。5~7月土壤盐分和养分共同影响着松嫩盐碱草地植物群落生物量，但是土壤盐分因子与群落生物量的相关性更明显（5月的Ca²⁺质量分数，6月和7月的Mg²⁺质量分数）。土壤盐分因子在整个生长季内对松嫩盐碱草地植物群落生物量的直接作用都大于土壤养分因子的。6月时影响松嫩盐碱草地植物群落丰富度、Simpson指数和Shannon指数的土壤养分因子增加，其中土壤全氮质量分数的直接作用是所有土壤因子中最大的。8月植物群落生物量、Simpson指数和Shannon指数仅受土壤盐分因子影响，其中生物量与土壤pH值以及Simpson指数与土壤碱化度都是极显著负相关，Shannon指数与土壤含盐量显著负相关。6~9月的松嫩盐碱草地植物群落均匀度也同时受土壤养分和盐分因子的作用，其中6月和9月时土壤盐分因子对群落均匀度的直接作用更突出。生长末期（9月）松嫩盐碱草地植物群落生物量与土壤因子间的关系以及生长初期（5月）植物群落均匀度与土壤因子间的关系都不明显。

Analysis on the Dynamic Relationships between Plant Community Characteristicsand Soil Factors in Western Songnen Saline-alkaline Grassland

By stepwise regression analysis, the relationships between soil factors and plant community characteristics, such as biomass richness, diversity and evenness, in western Songnen saline-alkaline grassland were studied during May and September. These plant community characteristics were simultaneously influenced by several soil factors, which changed complexly in different months. Soil salt and nutrition factors all influenced plant community biomass from May to July. However, soil salt factors had more relationship with plant community biomass, such as Ca²⁺ content in May, Mg²⁺ content in July. In the whole growth time, direct effects on plant community biomass from soil salt factors were more than those from soil nutrition factors. In June, the number of soil nutrition factors became more, which influenced plant community richness, Simpson index and Shannon index. Among those soil nutrition factors, the effect of content of total N was the largest. In August, plant community biomass, Simpson index and Shannon index were only influenced by soil salt factors, of which the relationships between biomass and soil pH and between Simpson index and soil ESP were both highly significantly negative correlation, the relationship between Shannon index and soil salt content was significantly negative correlation. Plant community evenness during June to September was also influenced by soil salt and nutrition factors, and soil salt factors had more direct effect in June and September. Plant community biomass had no obvious relationship with soil factors in the end of growth time (in September). No obvious relationship either existed between plant community evenness and soil factors in the beginning of growth time (in May).