等高反坡阶对滇西北高山峡谷区坡耕地玉米生长、土壤养分及微生物的影响OA

[Objective]The effects of contour reverse-slope terrace(CRT)on the growth,soil nutrients and microbial community of maize(Zea mays L.)in the alpine canyon area of northwestern Yunnan were investigated to provide a theoretical basis for the sustainable management of farmland ecosystem and res-toration of degraded habitats in this area.[Method]Using the maize cultivar"Yunrui 668"as the test material,high-throughput sequencing was employed to analyze the diversity and community composition of rhizosphere soil microorganisms at the seedling,tasseling,and maturity stages.Concurrently,maize growth indicators,yield,and soil nutrient contents were measured.[Result]① CRT significantly in-creased plant height,stem diameter,and biomass at different growth stages,with a yield increase of 12.67%.② Except for total nitrogen,CRT significantly increased soil nutrient contents at various growth stages while reducing soil pH.③ CRT significantly enhanced soil microbial diversity and richness.④CRT significantly increased the abundance of Actinobacteria at maturity,Basidiomycota at the seedling stage,and Mortierellomycota at the tasseling stage,while significantly decreasing the abundance of Asco-mycota and unclassified_k_fungi at the seedling stage.⑤ Correlation analysis revealed that soil microbial diversity was strongly correlated with maize growth indicators and soil nutrients.Redundancy analysis(RDA)further indicated that the main environmental factors affecting soil bacterial community structure were soil available potassium,ammonium nitrogen,organic matter,and total potassium,whereas the key factors influencing soil fungal community structure were total potassium,available potassium,and ammonium nitrogen.Partial least squares path modeling(PLS-PM)showed that soil bacterial and fungal diversity exerted positive and negative effects,respectively,on maize yield through their influence on soil physicochemical properties,though neither effect was significant.In contrast,soil physicochemical properties had a significant direct positive effect on maize yield.[Conclusion]CRT significantly im-proved soil physicochemical properties throughout the entire maize growth period,thereby enhancing soil microbial diversity and the abundance of dominant phyla at different growth stages.This,in turn,pro-moted maize growth and development and ultimately led to a significant increase in maize yield.