施肥影响根际丝足虫群落结构及其对作物产量的调控OA

[Objective]Cercozoa,as an important group of rhizosphere soil protists,are key participants driving microbial inter-actions and nutrient cycling processes.Elucidating the effects of long-term fertilization management practices on Cercozoan community composition and its regulatory effects on crop yield would help refine the role of Cercozoan in agricultural production and provide theoretical support for sustainable fertilization strategies based on soil biological regulation.[Methods]Five treat-ments were set up in a 13-year different fertilization positioning experiment:no fertilization(CK),chemical fertilizer alone(CF),chemical fertilizer combined with organic fertilizer(CFM),chemical fertilizer combined with organic fertilizer and straw incorporation(CFMS),and organic fertilizer combined with straw incorporation(MS).Based on this long-term positioning ex-periment,the rhizosphere soil Cercozoan community composition and its relationship with soil properties were investigated at different growth stages(jointing,heading,grain-filling,and maturity stages)of sorghum.Furthermore,the relationships among Cercozoan community structure,rhizosphere soil pathogenic fungi abundance,and crop yield were analyzed.[Results]Cercozoa were a dominant group of rhizosphere protists,with a relative abundance ranging from 13.69%to 45.85%.Different fertilization measures significantly affected the Cercozoa community structure,and Cercozoa abundance progressively increased as the growth stages advanced.Compared with the CK treatment,the CFM,CFMS,and MS treatments increased the abun-dance of the Cercozoan community and reduced the relative abundance of rhizosphere soil pathogenic fungi.Combined organic and inorganic fertilization significantly increased soil organic matter and total nitrogen content.Correlation analysis showed that rhizosphere soil organic matter and total nitrogen content were positively correlated with Cercozoa abundance and negatively cor-related with the relative abundance of pathogenic fungi.Cercozoan richness was negatively correlated with the relative abun-dance of pathogenic fungi,and significantly positively correlated with crop yield.Structural equation modeling indicated that fer-tilization may promote rhizosphere soil Cercozoa abundance and inhibit pathogenic fungi by improving soil properties,thereby increasing crop yield.[Conclusion]Long-term application of organic materials may increase Cercozoa species abundance,sup-press pathogenic fungi,and promote crop yield enhancement by enhancing soil organic matter and total nitrogen content.The results of this study provided a scientific basis for the biological control of soil pathogens in agricultural fields based on protist regulation and the formulation of sustainable fertilization strategies.