粤北喀斯特地区不同年龄油茶林土壤细菌群落动态变化特征

Dynamic Characteristics of Soil Bacterial Community Under Camellia oleifera Plantation with Different Ages in Karst Area of Northern Guangdong Province

[目的]明确油茶种植年限对喀斯特地区土壤微生物群落的影响。[方法]以乐昌市富树山油茶种植基地分别种植了2、3和7年的油茶林土壤为研究对象,利用高通量测序技术和分子生态网络的分析方法对土壤细菌群落进行研究。[结果]油茶种植年限的增加会导致土壤中铵态氮和总氮的积累,虽然不会显著改变土壤中细菌群落的生物多样性,但会导致土壤细菌群落结构的改变。同时发现土壤水分是影响2、3年龄油茶林土壤细菌群落的关键环境因子,而种植7年油茶林的土壤细菌群落主要受pH的影响。此外,相比种植2~3年的油茶林,种植7年的油茶林土壤细菌类群之间的联系更为紧密,但同时出现了细菌网络模块化的缺失和关键物种的演变的现象。[结论]本研究揭示了粤北石漠化地区不同种植年限油茶纯林的土壤细菌群落动态变化特征,为维持油茶林土壤生态系统功能的实践管理提供了理论依据。

[Objective]The large-scale plantation of Camellia oleifera forestry is a typical mode for the comprehensive management of rocky desertification in northern Guangdong with good economic benefits.However,the effects of planting years of Camellia oleifera forestry on soil microbial communities in karst areas are still unclear.[Method]Based on soils with planting years of 2,3,and 7 of Camellia oleifera plantation from Fushushan planting base in Lechang City of Guangdong Province,high-throughput sequencing and molecular ecological network analysis methods were used to analyze the soil bacterial community dynamic.[Result]The increase in planting years of Camellia oleifera could promote the accumulation of soil ammonium and total nitrogen contents.Although the community diversity of soil bacteria did not change significantly with the increase of planting years,significant variation was observed on bacterial community composition.Moreover,soil moisture content was the key environmental factor affecting soil bacterial community under Camellia oleifera forestry with 2 and 3 years,while soil bacterial community under Camellia oleifera forestry with plantation of 7 year was mainly affected by pH.In addition,compared with Camellia oleifera forest planted for 2 and 3 years,the soil bacterial taxa in the camellia oleifera forest planted for 7 years were more closely connected,but at the same time,there was a lack of modularity of the bacterial network and the evolution of key species.[Conclusion]This study reveals the dynamic characteristics of soil bacterial community with different planting years of Camellia oleifera in rocky desertification area of northern Guangdong,which provides a theoretical basis for the practical management in maintaining the soil ecosystem function of Camellia oleifera forestry.