马铃薯-棉花轮作体系下耕作方式与秸秆还田对棉花生长及根际微生物群落的影响OA

[Objective]This study aims to investigate the effects of different tillage practices combined with straw returning on cotton growth,yield,and rhizosphere soil bacterial communities in a potato-cotton rotation system,so as to provide a scientific basis for optimizing farmland management and improving soil microecological health in this system.[Methods]The cotton cultivar Xiang X1107 was used as material.Four treatments were designed:no-tillage(NT),no-tillage with straw returning(NTS),rotary tillage(T),and rotary tillage with straw returning(TS).Growth-related traits and biomass of cotton plant at key growth stages,as well as yield and its components were measured.High-throughput sequencing of the 16S rRNA gene was used to analyze the diversity and composition of rhizosphere soil bacterial communities at the boll-opening stage of cotton,and functional prediction was performed using the Functional Annotation of Prokaryotic Taxa(FAPROTAX).[Results]Straw returning and tillage practice had no significant effect on cotton emergence rate.Compared with no-tillage treatments(NT and NTS),rotary tillage treatments(T and TS)significantly increased plant height,stem diameter,and biomass at the seedling stage,and significantly increased boll weight.Whereas no significant differences in seed cotton yield and boll number were detected among all treatments.Straw returning treatments(NTS and TS)significantly elevated the Shannon Wiener's diversity index,Chaol index,and evenness index of rhizosphere bacterial communities,with NTS showing the highest values for all indices except the Shannon Wiener's diversity index.Principal coordinates analysis(PCoA)revealed that tillage practice was the primary factor driving the differentiation of bacterial community structure.Proteobacteria was the dominant phylum across all treatments.Straw returning(NTS and TS)significantly decreased the relative abundance of Proteobacteria,while significantly increased the relative abundances of Acidobacteriota and Actinobacteriota.At the genus level,no-tillage treatments(NTS and TS)enriched nitrogen-fixing-related genera including Burkholderia_Caballeronia_Paraburkholderia,Klebsiella,Bradyrhizobium,and Allorhizobium_Neorhizobium_Pararhizobium_Rhizobium complex,and FAPROTAX prediction confirmed a significant enhancement of nitrogen fixation function.Treatment enriched Pantoea and Pseudomonas,and increased the abundances of chemoheterotrophy and human pathogen all related functional groups,whereas TS treatment effectively reduced the risk of pathogenic bacteria.[Conclusion]NTS is conducive to maintaining soil microbial diversity,enhancing nitrogen fixation function,and reducing pathogenic bacteria risk,and is thus the recommended tillage mode in the potato-cotton rotation system.TS can serve as an alternative to promote early-stage growth and regulate microbial functions.Appropriate combination modes can be selected according to local soil conditions,ecological and economic objectives in agricultural production.