松嫩草原不同时间火烧后环境因子变化分析

松嫩草原火烧后，土壤表层硬度增加，早烧地硬度异质性程度增高，晚烧地降低。晚烧地土壤０￣５ｃｍ范围内窝重降低，早烧地与未烧地比无差异。火烧地土壤０￣３０ｃｍ范围内含水率降低，早烧地更低，表面差别最大，火烧地土壤含水率在春季严重亏缺。火烧地土壤温度在生长季内恒高于未烧地，平均温度亦高。群落平均温度低于未烧地，但白天火烧地群落温度高于未烧地，夜间群落温度低于未烧地，土壤表层温度波动幅度较大，火烧与未烧边

Change of Enviromental Factors after Burning in Songnen Grassland

In grassland burned in Songnen plain, the hardness of soil surface increased, the heterogeneity of hardness in early burned plot was increased, but in later burned plot reduced, Metri weight of soil in later burned plot was lower than that in early burned plot and unburned plot. Soil water content decreased in burned plot vs unburned plot, the content in early burned plot was less than later burned plot. Soil temperature inclinned in burned plot, bue the community temperature declinned in burned plot, even community temperature in burned plot in day was higher than that in unburned plot, in night conversly. The scale of edge effects between burned plot and unburned plot was 20 cm from bondary separatly. Transmission of sunlight to communite increased in burned plot. Finally, a hypothesis of fire effects by different burning time was discussed. Optimum burning time should be nearest to starting of organism regrowth, but latter burning from the starting also could satisfied some purpose including economics and ecology, meaning that some best effect could be produced.