岷江干旱河谷造林对土壤微生物群落结构的影响

Effects of afforestation on soil microbial community structure in the arid valley of Minjiang River

为了探讨不同造林时间和立地条件对土壤微生物群落结构的影响,采用磷脂脂肪酸(PLFAs)法测定了岷江干旱河谷地区不同造林时间(2002、2006和2011年)及不同立地条件(退耕地和宜林荒山地)营建的岷江柏人工林土壤微生物生物量及群落结构的变化情况。结果表明:由于造林时间较短,不同造林时间的人工林间土壤化学性质没有差异,但土壤微生物生物量和各菌群生物量差异显著,且随着造林时间的增加而增加。不同立地条件下则表现为退耕还林地土壤微生物生物量和各菌群生物量较高。说明土壤微生物对外界因素变化的反映更灵敏。相关性分析结果显示土壤全氮含量与土壤微生物生物量及各菌群生物量显著相关,是影响土壤微生物群落结构的关键因素。

In order to explore the effects of afforestation on soil microbial community structures in the arid valley of Minjiang River, we selected different plantations with different cultivation years and site conditions to investigate soil microbial biomass and community structures by phospholipid fatty acids （PLFAs） method. The results showed that soil chemical properties were different among the types but not significant due to their short plantation time, while the soil microbial biomass increased significantly with the plantation time. For plantations with different site conditions, soil microbial biomass was higher in the plantation returned from farmland. The findings of above indicate that the response of microbial to environmental changes is more sensitive than that of soil chemical properties. Soil microbial biomass had significant correlation with soil total nitrogen content. It suggests that soil total nitrogen content is the key factor affects the soil microbial community structures in these plantations.