粉垄耕作对耕地土壤细菌群落多样性及微生物网络结构的影响

Effect of Deep Vertical Rotary Tillage on Soil Bacterial Community Diversity and Microbial Network Structure in Cultivated Land

为了解粉垄耕作对耕地土壤细菌群落多样性和结构分布的影响,以及微生物生态分子网络结构和物种之间的相互作用关系.以宁夏引黄灌区不同耕作方式下耕地土壤为研究对象,设置粉垄耕作(DVRT)和传统耕作(CT)这2种处理,采用Illumina MiSeq技术对不同处理的耕地土壤细菌群落进行了分子生态网络分析.结果表明,0~20 cm土层中,DVRT比CT处理显著提升了总有机碳(TOC)、总氮(TN)、碱解氮(AN)、总磷(TP)、有效磷(AP)和总钾(TK)的含量;20~40 cm土层中,DVRT比CT处理显著提升了TOC、 TN、 TP、 AP、 TK和有效钾(AK)的含量.DVRT处理的含水量(WC)显著提高了8.13%~13.30%,pH和电导率(EC)分别降低了4.51%~5.85%和12.5%~13.33%.玉米不同生育期和土层中,DVRT处理的Shannon和Ace指数均增加.优势细菌门为:放线菌门、变形菌门、绿弯菌门、酸杆菌门和芽单胞菌门.细菌群落β多样性结果显示,DVRT和CT处理的土壤细菌群落结构差异明显.冗余分析和偏曼特尔检验结果表明,pH、 EC和TP是影响细菌群落结构多样性的关键环境因子.分子生态网络分析表明,DVRT处理的微生物网络由更多功能相关的微生物模块组成,关键微生物的拓扑作用与CT处理不同.综上,粉垄耕作可以提升不同土层的土壤养分和WC,降低pH和EC,改善耕地土壤细菌群落多样性和微生物网络结构并增强耕地土壤中潜在的生态系统功能.

The aim of this study was to understand the effect of deep vertical rotary tillage on the diversity and structural distribution of a soil bacterial community in cultivated land,as well as the interactions between microbial ecological molecular network and species.In this study,the cultivated soil under different tillage methods in the Yellow River diversion irrigation area in Ningxia was selected as the research object,and two treatments were set up,namely,deep vertical rotary tillage(DVRT) and conventional tillage(CT).Then,Illumina MiSeq technology was used to analyze the molecular ecological network of soil bacterial community under different tillage methods in the Ningxia Yellow River irrigation area.The results showed that DVRT significantly increased the contents of total organic carbon(TOC),total nitrogen(TN),alkali-hydrolyzed nitrogen(AN),total phosphorus(TP),available phosphorus(AP),and total potassium(TK) in the 0-20 cm soil layer compared with those in the CT treatment.Compared with those in the CT treatment,DVRT significantly increased the contents of TOC,TN,TP,AP,TK,and available potassium(AK) in the 20-40 cm soil layer.DVRT treatment significantly increased water content(WC) by 8.13%-13.30% and decreased pH and electrical conductivity(EC) by 4.51%-5.85% and 12.5%-13.33%,respectively.In different growth stages and soil layers of maize,the Shannon and Ace indices were increased in the DVRT treatments.The dominant bacterial phyla were:Actinobacteria,Proteobacteria,Chloroflexi,Acidobacteriota,and Gemmatimonadota.The results of bacterial community β diversity showed that DVRT and CT had significant differences in bacterial community structure.The redundancy analysis and Partial Mantel test results showed that pH,EC,and TP were the key environmental factors affecting the structural diversity of bacterial communities.Molecular ecological network analysis revealed that DVRT treatment microbial networks consisted of more functionally related microbial modules,and the topological roles of key microorganisms were different from those in the CT treatment.In conclusion,DVRT can enhance soil nutrients and WC in different soil layers,reduce pH and EC,improve soil bacterial community diversity and microbial network structure,and also enhance the potential ecosystem functions in cultivated soil.