不同添加量凋落物及生物质炭对土壤微生物群落结构的影响

以亚热带杉木人工林土壤为研究对象,采用培养试验,研究了杉木凋落物及其生物质炭(Biochar,BC)在不同添加量条件下(0、1%、2%、3%、4%、5%土壤质量分数)对土壤微生物群落结构的影响.结果表明:凋落物处理的土壤微生物总磷脂脂肪酸(PLFA)、细菌、真菌含量均随添加量的增加而增加,而丛枝菌根真菌(AMF)和放线菌(ACT)含量在不同添加量处理间则无显著差异.对于BC处理,在3%添加量下土壤微生物总PLFA、革兰氏阳性细菌(GP)、革兰氏阴性细菌(GN)、真菌、AMF和ACT含量均达到最大,表明BC对土壤微生物活性的促进作用与凋落物截然不同.此外,凋落物添加对真菌的影响较大,但对ACT的影响则显著低于BC处理.主成分分析表明,凋落物和BC添加均显著改变了土壤微生物群落结构,且前者的影响更为明显,而添加量对其影响则较小.冗余分析发现,土壤全氮与C/N比值分别为影响凋落物与BC处理中微生物群落结构变化的主要因子.

Effects of Chinese fir litter and its biochar amendment on soil microbial community structure

An incubation experiment was conducted to investigate the effects of the Chinese fir litter and its biochar (BC) with the different addition rates (0, 1%, 2%, 3%, 4% and 5% of soil mass) on the soil microbial community structure. Results indicate that soil total phospholipid fatty acids (PLFAs), bacterial and fungal PLFAs content increased with litter addition rate, while the PLFAs contents of arbuscular mycorrhizal fungi (AMF) and actinomycetes (ACT) with all addition rates were not significant. However, 3% BC treatment obtained the highest soil total PLFAs, gram positive bacteria (GP), gram negative bacteria (GN), AMF, ACT and fungal PLFAs content, suggesting that BC treatment effects on soil microbial activity was different from litter treatment. In addition, litter had a greater effect on fungi, but litter treatment effect on ACT were significantly lower than that of BC treatment with the same addition rate. Furthermore, results of principal component analysis show that soil microbial community structure significantly changed due to litter or BC addition and litter treatment was more significant, while the effect of addition rate on soil microbial community structure was relatively smaller. Redundancy analysis indicates that the soil total nitrogen content and C/N ratio were the main factors affecting the change of microbial community structure in litter and BC treatments, respectively.