艾比湖地区冻融作用对土壤微生物数量和群落结构的影响

Effects of Freezing-Thawing on Soil Microbial Quantity and Community Structure Around the Ebinur Lake

通过对艾比湖地区冻融阶段7个典型样地野外采样和室内分析,研究了冻融作用条件下土壤微生物数量与土壤性质的关系、土壤微生物数量变化特征和土壤微生物群落结构的变化特征.结果表明：不同冻融阶段,不同种类微生物数量受到不同土壤理化因子的制约.1月,细菌数量与土壤有机质含量呈显著正相关（P〈0.05）,真菌数量与土壤含水量和土壤有机质含量呈极显著正相关（P〈0.01）,与土壤全氮和土壤孔隙度呈显著正相关（P〈0.05）;3月,只有真菌数量与土壤含水量呈极显著正相关（P〈0.01）;4月,放线菌数量与土壤有机碳和全氮含量呈显著正相关（P〈0.05）,然而与土壤pH值呈显著负相关（P〈0.05）.总体来讲,冻结期土壤微生物数量较低,冻融后期（4月）达到峰值,其中,7 a撂荒地的微生物数量最高,3 a撂荒地最低.在研究区寒冷季节,微生物类群中放线菌占主导地位（81.9%）;融化阶段,则是细菌占主要地位（52.1%~53.9%）.

The relationship between soil microbial quantity and soil property,variation characteristics of soil microbial quantity and soil microbial community structure in seven typical plots during freezing-thawing in Ebinur Lake area were studied. The results show that：（ 1） different types of soil microbial quantity are dependent on physico-chemical factors at different stages of freezing-thawing. In January,bacteria quantity and soil organic matter content are significant positive correlation（ P 0. 05）,fungi quantity has extremely significant positive correlation with soil water content and soil organic matter content（ P 0. 01）,also has significant positive correlation with soil total N and soil porosity（ P 0. 05）; in March,only fungi quantity has extremely significant positive correlation with soil water content（ P 0. 01）; in April,actinomycetes quantity has significant positive correlation with soil organic carbon and total N（ P 0. 05）,but has significant negative correlation with soil pH value（ P 0. 05）;（ 2） soil microbial quantity is lower during frozen period in the study area（ 92 275367 250 CFU · g1）,and reaches a peak in the late freezing and thawing period（ 170 738704 300 CFU·g1in April）; 7-year abandoned land has the highest microbial quantity（ 434 625 CFU · g1）,while 3-year abandoned land has the lowest one（ 177 435 CFU·g1）;（ 3） in cold season,actinomycetes are dominant in the study area（ 81. 9%）; in thawing stage,bacterial is dominant（ 52. 1%53. 9%）. On the whole,soil microbial growth is limited by nitrogen source in this study area.