Effects of continuous chemical fertilizer combined with organic manure on soil bacterial community structure and functional groups in tea gardens
To evaluate the effects of combined application of organic and chemical fertilizers on the structure and diversity of soil bacterial communities,we conducted a six-year field plot experiment on a tea garden in acid red soils in the subtropical zones of hilly areas of eastern Fujian.The five treatments included no fertilizer(CK),100% chemical fertilizers(CF),100% chemical fertilizer+clean-cultivated(CFC),organic manure combined with chemical fertilizer(OF),and organic manure combined with chemical fertilizer+green manure(OFM).The effects of different fertilization practices on bacterial community diversity,community structure,functional groups,and co-occurrence network structure in acid tea garden soils were analyzed with Illumina Novaseq PE 300 high-throughput sequencing technology.The results showed that:compared with CK treatment,CF treatment decreased soil pH,but significantly increased soil alkaline nitrogen and total phosphorus.Compared with CK treatment,OF and OFM treatments increased available nutrients and soil organic matter content while increasing soil pH.Compared with CK treatment,CF and CFC treatments decreased the alpha diversity index of the soil bacterial community,while Sobs,Ace,Chao1,and Shannon indices(P<0.05).Non-metric Multidimensional Scaling and analysis of similarities analysis both showed a significant difference in soil bacterial community structure between the soils under different fertilization measures(R2=0.442 1,P=0.001),such that OF treatment enriched species that were beneficial to soil carbon and nitrogen cycling and inhibited pathogens.FAPROTAX function prediction showed that the chemoheterotrophy,aerobic chemoheterotrophy,nitrogen fixation,cellulolysis,and nitrate reduction was mainly an ecological function of tea garden soil bacteria.Compared with CK treatment,the abundance of functional groups of predatory or exoparasitic,photoheterotrophy,phototrophy,anoxygenic photoautotrophy S oxidizing,anoxygenic photoautotrophy,and nitrogen-cycling functional genes were improved in OF treatment.The treatments of fertilization increased the numbers of network edges,average connective degree,and average number of neighbors in the soil bacterial co-occurrence networks,indicating that the soil bacterial co-occurrence network was complex under all fertilizing treatments.The bacterial co-occurrence networks were dominated by positive interactions(58.03%-77.78% ),and the competition between species was strengthened after the implementation of the different fertilization measures.The fertilization measures increased the average path length and reduced the average clustering coefficient.This means that the response rate of bacterial action was slowed and the stability of the community structure was improved.Additionally,the stability of bacterial community structure treated by organic fertilizer combined with chemical fertilizer was better than that treated by chemical fertilizer alone.The results of the redundancy analysis and Mantel test showed that available phosphorus and pH were the main factors affecting the abundance and diversity of the soil bacterial community.In conclusion,organic manure combined with chemical fertilizer changes the community structure and the functional groups of soil bacteria,promotes soil bacteria carbon and nitrogen cycle metabolism,enriches beneficial bacteria,and increases the bacterial co-occurrence network scale,interaction,and stability,and thus is beneficial for building a healthy and stable bacterial community.
tea garden soilorganic manure combined with chemical fertilizerbacterial diversitysoil bacterial community structurebacterial functional group
万方数据
维普
