木霉菌肥对土壤团聚体微生物群落的影响

Effects of Trichoderma fertilizer on soil microbial community of soil aggregates

[目的]探究木霉菌肥对不同粒级团聚体微生物群落结构和多样性的影响,为提升土壤质量提供科学依据。[方法]以典型潮土为研究对象,设置单施化肥(CK)、木霉菌肥氮替代10%化肥氮(T1)、20%化肥氮(T2)、30%化肥氮(T3)和40%化肥氮(T4)处理。测定土壤基本理化性质、团聚体组成和稳定性,并用磷脂脂肪酸法分析团聚体微生物群落结构和相对丰度。[结果]随木霉菌肥施用量的增加土壤有机碳、全氮和矿质氮含量增加,土壤容重和pH值则呈现出逐渐降低的趋势。与CK相比,木霉菌肥显著增加>2 mm团聚体含量,且T3处理增幅最大为28.9%,T1和T4处理<0.25 mm团聚体含量显著增加。与CK相比,随木霉菌肥施用量的增加,团聚体稳定性先增加后降低,T3处理平均重量直径增幅最大为21.9%,而T1和T4处理平均重量直径无显著差异。木霉菌肥显著增加各粒级团聚体微生物总磷脂脂肪酸(PLFA)、真菌PLFA、细菌PLFA和放线菌PLFA,增加真菌/细菌比值,增加土壤生态系统的稳定性。T3处理各粒级团聚体真菌PLFA/细菌PLFA比值增幅最大。木霉菌肥施用降低1~2、0.5~1和0.25~0.5 mm团聚体G+PLFA/G-PLFA比值,改善土壤营养状况。由相关性分析可知,土壤团聚体碳氮与团聚体微生物群落显著正相关,pH与真菌PLFA/细菌PLFA的比值显著负相关(R=-0.113,P<0.05)。[结论]木霉菌肥通过改变土壤有机碳、全氮和pH,增加土壤团聚体稳定性并改善团聚体微生物群落结构,适量施用木霉菌肥可以改善土壤微环境,提升土壤质量。

[Objective]The purpose of the current research was to explore the effects of Trichoderma fertilizer on microbial community structure and the diversity of soil aggregates at different particle sizes,and to provide a scientific basis for improving soil quality. [Methods]The typical fluvo-aquic soil fields were selected and five application treatments including chemical fertilizer(CK),Trichoderma fertilizer substitute at 10%(T1),20%(T2),30%(T3)and 40%(T4)were conducted. The basic soil physicochemical properties,aggregate composition and stability were determined;the microbial community structure and the relevance abundance in different aggregate fractions were detected by phospholipid fatty acid(PLFA)method. [Results]Soil organic carbon,total nitrogen and mineral nitrogen were increased with the increase of Trichoderma fertilizer application rates,while soil bulk density and pH tended to be decreased. Compared with CK,Trichoderma fertilizer significantly increased the content of aggregates >2 mm,and the maximum increase was 28. 9% in T3 treatment,and the content of aggregates <0. 25 mm in T1 and T4 treatments were increased significantly(p<0. 05). Compared with CK,the stability of aggregates was first increased and then decreased. The highest increase of the average weight diameter was observed with T3 treatment at21. 9%,while no significant difference was observed in T1 and T4 treatments. The total PLFA content,fungal PLFA,bacterial PLFA,actinomycete PLFA,and the ratio of fungi/bacteria were all increased by Trichoderma fertilizer application,which enhanced the stability of soil ecosystem. The greatest increases of the ratio of fungal PLFA/bacterial PLFA in the aggregates of each particle size was observed in T3 treatment with the application of Trichoderma fertilizer,while the ratio of G+PLFA/G-PLFA was significantly decreased in aggregates of 1~2,0. 5~1 and 0. 25~0. 5 mm,and the nutrient status of soil was improved. The correlation analysis showed that organic carbon and total nitrogen content were significantly and positively correlated with the aggregate microbial community,and pH was negative correlated with the ratio of fungal PLFA/bacterial PLFA(R=-0. 113,P< 0. 05). [Conclusion]The current study revealed that Trichoderma fertilizer improved soil aggregate stability and microbial community structure by changing the content of soil organic carbon,total nitrogen and pH value.Appropriate application rate of Trichoderma fertilizer can improve soil micro-environment and improve the soil quality.