Alfalfa is a perennial herbaceous forage legume that is remarkably and negatively affected by monocropping.However,the contribution of the changes in bacterial communities to soil sickness in alfalfa have not been elu...Alfalfa is a perennial herbaceous forage legume that is remarkably and negatively affected by monocropping.However,the contribution of the changes in bacterial communities to soil sickness in alfalfa have not been elucidated.Therefore,we investigated bacterial community structures in response to monocropped alfalfa along the chronosequence.Continuous cropping remarkably reduced bacterial alpha diversity and altered community structures,and soil pH,total P and available P were strongly associated with the changes of bacterial diversity and community structures.Intriguingly,10 years of monocropped alfalfa might be a demarcation point separating soil bacterial community structures into two obvious groups that containing soil samples collected in less and more than 10 years.The relative abundances of copiotrophic bacteria of Actinobacteria and Gammaproteobacteria significantly increased with the extension of continuous cropping years,while the oligotrophic bacteria of Armatimonadetes,Chloroflexi,Firmicutes and Gemmatimonadetes showed the opposite changing patterns.Among those altered phyla,Actinobacteria,Chloroflexi,Alphaproteobacteria and Acidobacteria were the most important bacteria which contributed 50.86%of the community variations. Additionally, the relative abundances of nitrogen fixation bacteria ofBradyrhizobium and Mesorhizobium obviously increased with continuous cropping years, while theabundances of Arthrobacter, Bacillus, Burkholderiaceae and Microbacterium with potential functionsof solubilizing phosphorus and potassium remarkably decreased after long-term continuouscropping. Furthermore, bacterial cooccurrence patterns were significantly influenced by continuouscropping years, with long-term monocropped alfalfa simplifying the complexity of the cooccurrencenetworks. These findings enhanced our understandings and provided references for forecasting howsoil bacterial communities responds to monocropped alfalfa.展开更多
基金This work was supported by grants from National Key Research and Development Program of China(2017YFD0200604)Key Research Program of Frontier Sciences,CAS(ZDBS-LYDQC017)+5 种基金the National Natural Science Foundation of China(41671251)Earmarked Fund for China Agriculture Research System(CR34)Heilongjiang Provincial Natural Science Foundation of China(D2018009)the Grass-field Rotation Scientist Studio of Heilongjiang Province(202004)Outstanding Youth Fund of Heilongjiang Academy of Agricultural Sciences(2020JCQN003)Youth Innovation Promotion Association,CAS(2017276).
文摘Alfalfa is a perennial herbaceous forage legume that is remarkably and negatively affected by monocropping.However,the contribution of the changes in bacterial communities to soil sickness in alfalfa have not been elucidated.Therefore,we investigated bacterial community structures in response to monocropped alfalfa along the chronosequence.Continuous cropping remarkably reduced bacterial alpha diversity and altered community structures,and soil pH,total P and available P were strongly associated with the changes of bacterial diversity and community structures.Intriguingly,10 years of monocropped alfalfa might be a demarcation point separating soil bacterial community structures into two obvious groups that containing soil samples collected in less and more than 10 years.The relative abundances of copiotrophic bacteria of Actinobacteria and Gammaproteobacteria significantly increased with the extension of continuous cropping years,while the oligotrophic bacteria of Armatimonadetes,Chloroflexi,Firmicutes and Gemmatimonadetes showed the opposite changing patterns.Among those altered phyla,Actinobacteria,Chloroflexi,Alphaproteobacteria and Acidobacteria were the most important bacteria which contributed 50.86%of the community variations. Additionally, the relative abundances of nitrogen fixation bacteria ofBradyrhizobium and Mesorhizobium obviously increased with continuous cropping years, while theabundances of Arthrobacter, Bacillus, Burkholderiaceae and Microbacterium with potential functionsof solubilizing phosphorus and potassium remarkably decreased after long-term continuouscropping. Furthermore, bacterial cooccurrence patterns were significantly influenced by continuouscropping years, with long-term monocropped alfalfa simplifying the complexity of the cooccurrencenetworks. These findings enhanced our understandings and provided references for forecasting howsoil bacterial communities responds to monocropped alfalfa.
