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通过对大兴安岭重度火烧迹地不同坡度和坡向的土壤微生物群落进行调查研究,旨在揭示重度火烧迹地过火6a后森林恢复过程土壤微生物群落的变化规律与影响因素。研究结果表明:平地土壤微生物生物量碳含量(MBC)和土壤微生物生物量碳氮比(MBC/MBN)均高于坡地,其中MBC/MBN达到差异极显著水平。平地土壤微生物的代谢活性AWCD值、对31种4类碳源(糖类、脂类、氨基酸、代谢物)的利用能力和Shannon-Winner多样性指数(H’)均极显著低于坡地。西坡土壤微生物AWCD值和H’高于南坡,但AWCD和H’与土壤养分、pH值、EC无显著相关关系,说明坡向可能与土壤微生物代谢活性和多样性的关系并不密切,反映了两坡向土壤微生物群落结构的相似性。坡度由于影响了土壤养分和水分条件,进而影响了土壤微生物的生物量、群落结构、物种多样性和碳源利用能力。火烧迹地恢复初期平地土壤微生物量碳高于坡地,西坡高于南坡;恢复6a后,土壤微生物量碳的差异已不显著,但土壤微生物群落结构、物种多样性以及代谢特性仍具有显著差异,这可能与地形坡度仍然显著影响土壤水分含量的因素有关。
Through the investigation on the soil microbial communities with different slopes and slopes in the heavy fire burned area of the Greater Hinggan Mountains, this paper aims to reveal the variation regularities and influencing factors of soil microbial communities in the process of forest restoration after heavy fire burned over 6a. The results showed that both MBC and MBC / MBN in the plain were higher than those in the slope, MBC / MBN reached the extremely significant difference. The AWCD value of soil active metabolite of flat soil was significantly lower than that of the slope on the utilization ability of 31 kinds of carbon sources (carbohydrates, lipids, amino acids and metabolites) and Shannon-Winner diversity index (H ’). AWCD and H ’of the western slope were higher than those of the southern slope, but there was no significant correlation between AWCD and H’ and soil nutrient, pH and EC, which indicated that the relationship between slope aspect and soil microbial metabolic activity and diversity was not close, It reflects the similarity of soil microbial community structure between two slopes. The slope affected soil nutrient and water conditions, thus affecting soil microbial biomass, community structure, species diversity and carbon source utilization ability. In the early stage of restoration, the soil microbial biomass carbon was higher than the slope, and the west slope was higher than that on the southern slope. After the restoration of 6a, the difference of soil microbial biomass carbon was insignificant, but the soil microbial community structure, species diversity and metabolic characteristics were still significantly different , Which may be related to the fact that the topographic gradient still significantly affects the soil moisture content.