Effects Of Green Manure Incorporation On Soil Nutrients,Bacterial Community Structure And Maize N And P Use Efficiency In Yellow Soil Of Guizhou

The available nutrients of yellow soil are lacking in Guizhou,green manure is a kind of bio-organic fertilizer source,which has a positive effect on soil fertilizer and crop production.In this study,a typical yellow soil maize field in Guizhou was planted with green manure in winter,and five treatments were set: winter fallow +no fertilizer,winter fallow + traditional chemical fertilizer（WF）,alfalfa + traditional chemical fertilizer（AL）,common vetch（Vicia sativa L.）+ traditional chemical fertilizer（VS）,rape + traditional chemical fertilizer（RA）.The effects of different green manure types on N and P nutrient use efficiency of maize and soil nutrients were studied,in order to find out the key influencing factors of green manure on crop nutrient use efficiency,and to provide theoretical basis for green manure planting and incorporating to the yellow soil idle winter fields in Karst mountainous areas of Guizhou Province.The main results are as follows:（1）In 2020 and 2021,the N and P content and uptake of maize grains,stalks and leaves were increased by incorporating alfalfa and common vetch green manure.Compared with WF,N and P agronomic efficiency,N and P uptake efficiency and N and P use efficiency of maize were increased by two legume green manure,while rape green manure were decreased.Compared with WF,the agricultural efficiency,uptake and use efficiency of N increased by 80.69%,62.49% and 23.19%,respectively,and that of P increased by 48.50%,35.33% and 7.73%,respectively.（2）Compared with WF,Soil p H decreased,soil organic matter,total nitrogen,ammonium nitrogen,total phosphorus and available phosphorus content increased,and the activities of soil catalase,urease,sucrase and acid phosphatase increased by3.46%～21.13%,5.77%～42.31% and 0.67%～23.44% and 19.25%～38.45%,respectively.Soil bacteria Shannon index and Ace index were higher than CK.Compared with WF treatment,the abundance of Actinobacteriota was decreased and Proteobacteria was increased in green manure treatment,but the difference was not significant（P>0.05）.（3）N use efficiency was significantly positively correlated with soil bacterial Shannon index,Ace index,Chao index,bacterial coverage,total nitrogen,available phosphorus and microbial biomass carbon,and significantly negatively correlated with soil organic matter and acid phosphatase（P<0.05）.P use efficiency was significantly positively correlated with ammonium nitrogen,nitrate nitrogen,N use efficiency,catalase,urease and sucrase activities（P<0.05）.Green manure explained 32% of soil properties and 70% of soil bacterial diversity,50% of N use efficiency and 67% of P use efficiency,respectively.In conclusion,incorporating legume green manure,especially alfalfa green manure,to the winter fallow field can effectively improve the yellow soil nutrients and soil enzyme activities,and then improve N and P nutrient use efficiency of maize.