The saline-sodic soil has the largest distribution in the west of Songnen plain of China,its surface vegetation often has plaque distribution,and salinization degrees under different vegetations are different.To analyze salinization degree by soil indicators for classification has the advantages of being accurate,fast and direct,but the relationship between soil indicators and vegetation types must be established first.The differences of soil salinity,nutrients and microbes were studied by field sampling,and scientificity of degree classification of soil salinization by correlation analysis and clustering analysis was explained.The results showed that soil nutrients,number of microbes and enzyme activity have significant differences in different types of salinized grassland (P＜0.05),salinity of Leymus chinensis grassland soil is the lowest,but soil nutrients,number of microbes and enzyme activity of it are the highest;salinity of bare saline-sodic soil is the highest,but soil nutrients,number of microbes and enzyme activity of it are the lowest.Correlation analysis showed that soil salinization degree,soil nutrients and number of microbes are correlated with grassland types (P＜0.05).Clustering analysis of comprehensive soil indicators such as soil salinity,nutrients and number of microbes showed that Leymus chinensis is slight saline and alkaline land,Phragmites australis and Chloris virgata are middle saline and alkaline land,Saueda glauca,Puccinellia chinampoensis and bare saline-sodic soil are heavy saline and alkaline land.%松嫩平原西部是我国苏打盐碱化草地的主要分布区,地表植被常呈斑块化分布,不同植被下土壤盐碱化程度迥异.通过植被进行土壤盐碱化诊断分级具有快速、直观的优点,但首先必须建立植被与土壤指标间的量化关系.采用田间取样调查的方法分析了不同草地类型下土壤盐分、养分及微生物的差异,并利用相关分析和聚类分析等统计方法阐明了采用植被进行土壤盐碱化分级的科学性.结果表明:不同盐碱化草地土壤盐分、养分、微生物数量及酶活性存在显著差异(P＜0.05),羊草草地土壤盐分最低,养分、土壤微生物数量及酶活性最高;盐碱裸地土壤盐分最高,养分、土壤微生物数量及酶活性最低;聚类分析结果显示,羊草草地属于轻度盐碱化,芦苇和虎尾草草地为中度盐碱化,碱茅、碱蓬草地和盐碱裸地为重度盐碱化.
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