Microbial Community Structure Characteristics at the Water-Soil Interface in Rice-Crab Co-Culture System
[Objective]The rice-crab co-culture is a predominant three-dimensional ecological cultivation model in northern Chinese rice fields.The water-soil interface is a key area for material cycling within this system.In this paper,studying the diversity and structure of microbial communities at this interface aimed to understand its evolution and support research on the ecological health of water and soil in rice-crab co-culture systems.[Method]Eight long-term rice monoculture systems and eight long-term rice-crab co-culture systems(＞20 years)were selected in a typical rice-crab co-cultivation area in Panjin,Liaoning province.Based on measurements of physicochemical indicators of rice field water and soil,as well as high-throughput sequencing technology of the 16S rRNA gene,the study compared the effects of two rice cultivation systems on the properties and bacterial community structures of the water-soil interface in paddy fields.[Result](1)The introduction of crabs significantly reduced the unique microbial communities at the water-soil interface.Specifically,the number of unique operational taxonomic units(OTUs)in surface water and interfacial soil decreased by 27.0%and 71.2%,respectively.However,the introduction of crabs had no significant effect on alpha diversity in surface water,but it reduced the richness of bacterial communities in interfacial soil.(2)The introduction of crabs significantly altered the structure and composition of the water-soil interface bacterial community.The introduction of crabs significantly increased the relative abundance of Proteobacteria(30.4%)and decreased the relative abundance of Acidobacteria(39.9%)in surface water.Simultaneously,it increased the relative abundance of Planctomycetes(21.1%)and decreased the relative abundance of Ignavibacteriae(15.1%)and Nitrospirae(21.7%)in interfacial soil.(3)Proteobacteria and Bacteroidetes were not only core species at the water-soil interface of rice field systems,but also key species in co-occurrence networks,playing important roles in stabilizing ecological networks.(4)The introduction of crabs into rice fields increased the complexity and stability of the bacterial co-occurrence network in the interface soil,but decreased it in the paddy field water.(5)Linear regression analysis showed that NO3--N concentration in surface water and interface soil pH were the main driving factors influencing the diversity and stability of their respective bacterial community structures.[Conclusion]The introduction of crabs significantly altered the microbial community structure and diversity at the water-soil interface in rice fields.The increase in nutrient salts in the water posed a risk of reducing the stability of the aquatic microbial community.However,the rice-crab co-culture shaped a more stable bacterial community in the interface soil,which facilitated nutrient cycling and enhanced crop nutrient utilization efficiency.
rice-crab co-culturesurface water bacteriainterface soil bacteriaco-occurrence networkphysicochemical properties
国家科技期刊平台
NSTL
万方数据
