科尔沁沙地和浑善达克沙地流动沙丘中土壤微生物学特征比较

通过对科尔沁沙地和浑善达克沙地流动沙丘中0～10 cm和>10～20 cm层土壤中微生物数量和生物量碳的比较表明:土壤微生物三大类群(细菌、放线菌和真菌)数量和微生物生物量碳均表现为浑善达克沙地 > 科尔沁沙地，其中两大沙地真菌数量差异显著，细菌和放线菌数量差异不显著，微生物生物量碳差异显著；两大沙地土壤微生物数量和生物量碳在不同土壤层次均表现为>10～20 cm 层高于 0～10 cm层，其中微生物三大类群数量差异均不显著，微生物生物量碳差异显著. 土壤性质的差异导致两大沙地流动沙丘中微生物数量和生物量碳略有不同. 细菌和真菌数量与土壤有机碳和土壤全氮呈显著正相关，与土壤水分含量和pH呈显著负相关，微生物生物量碳与土壤有机碳和土壤全氮呈显著正相关. 两大沙地土壤微生物与土壤养分的层化比率均小于1，科尔沁沙地中微生物数量、生物量碳和土壤养分的层化比率均大于浑善达克沙地，可以推断两大沙地的流动沙丘处于退化状态，而且浑善达克沙地退化速度更快. 

Comparison of Soil Microbial Features in Mobile Dunes from Horqin and Otindag Sands in Northern China

Typical mobile dunes in Horqin Sands and Otindag Sands were chosen to investigate the soil microbial population and biomass carbon in the 0-10 cm and >10-20 cm soil layers. Results showed that soil microbial population and biomass carbon in Otindag Sands were greater than those in Horqin Sands. The difference of fungal population between Horqin and Otindag was significant, while the differences of bacterial and actinomycetic population were both statistically insignificant. Their biomass carbon also showed significant differences. Microbial population and biomass carbon at the two layers showed that the >10-20 cm was greater than the 0-10 cm layer in both the Otindag and Horqin Sands. The difference of microbial population between the two layers was not significant, while microbial biomass carbon was significantly different. The differences of soil properties resulted in the differences of microbial population and biomass carbon between the Horqin and Otindag Sands. Correlations were remarkably positive among bacterial and fungal population, soil organic carbon content and soil total nitrogen content, but negative among bacterial and fungal population, soil water content and pH value. Microbial biomass carbon displayed a significantly positive correlation with soil organic carbon content and soil total nitrogen content. Soil microbial and organic matter stratification ratios were below 1 in both Horqin and Otindag Sands. Microbial population, biomass carbon and organic matter stratification ratios in Horqin Sands were higher than those in Otindag Sands, which indicated that the mobile dunes in both Horqin and Otindag Sands were in a state of degradation. The degradation rate was greater in Otindag than in Horqin Sands.