间作作物种间相互作用对土壤细菌群落的影响

为揭示作物种植模式对土壤细菌群落组成及功能的影响机制，利用田间定位试验，基于宏基因测序方法，开展连续单作马铃薯（P）、单作玉米（M）、间作马铃薯（IP）、间作玉米（IM）根际土壤细菌群落组成和功能差异研究，分析土壤细菌群落结构、功能与土壤理化性状、间作作物产量间的相互关系。结果表明：与对应单作处理相比，玉米、马铃薯间作整体上具有产量优势。土壤变形菌门、放线菌门和浮霉菌门为不同处理下细菌群落的优势菌群；属分类水平上链霉菌属、慢生根瘤菌属、鞘脂单胞菌属、伍氏束缚菌属、伯克氏菌属、藤黄色杆菌属为优势菌属。马铃薯单作及间作处理下根际土壤鞘脂单胞菌属相对丰度均极显著高于玉米处理 （P<0.01）。通过KEGG数据库不同功能层的功能预测表明，不同处理得到455个三级功能类别和9 636个四级类别，其中参与C、N循环的通路数最多。相关性分析表明，土壤含水量（SOW）、土壤呼吸强度（RI）和速效磷（AP）对根际土壤细菌群落组成及功能代谢具有积极影响；SOW、RI和AP与功能类别中K01990和K06147均有显著或极显著相关性。连续6 a马铃薯、玉米间作及单作下作物根际土壤细菌群落组成和功能的变化是由作物种间关系变化驱动土壤养分、土壤微生物功能代谢差异影响的。

Effects of Intercropping Crop Interactions on Soil Bacterial Community Structure and Function

This study aimed to investigate the effects of the differential mechanisms of crop planting patterns on the soil bacterial community composition and function.Long-term fixed experiment treatments of monoculture potato (P),monoculture maize (M),and intercropped potato (IP) with maize (IM) were selected,and the rhizosphere soil bacterial communities structure and function differences were studied using metagenome sequencing.The study also examined the relationship among soil bacterial community structure,function ,soil physicochemical properties and the crop yields.The results showed that intercropping maize with potato had a significant advantage in crop yields compared with the monoculture.Proteobacteria,Actinobacteria and Planctomycetes were the dominant phylum under the different treatments,while the Streptomyces,Bradyrhizobium,Sphingomonas,Conexibacter,Burkholderiales and Koserellawere the dominant genus.The relative abundance of Sphingolipidium in patato rhizosphere was significantly higher than maize under the reatment of monculture and intercropping (P<0.01).The functional prediction between different category levels using KEGG database showed that 455 third-level functional level and 9 636 fourth-level functional category were classified,and the metabolic pathways involved in the carbon and nitrogen cycles was the most.Correlation analysis revealed that soil moisture content (SOW),soil respiration intensity (RI) and available phosphorus (AP) positively influenced bacterial community composition and functional metabolism in rhizosphere soil.Positive or negative correlationship with significant or extremely significant difference were observed between the metabolic patharys of K01990 and K06147 in the functional level category and SOW,RI,and AP.This study concluded that bacterial community composition and function in the rhizosphere of intercropped potatoe and maize,and nonoculture maize and potato were drived by differences in soil nutrient and soil microbial function.