Study On The Nutrient Release Of Straw Returning To The Field And Its Regulation Effect On Soil Microecological Characteristics And Maize Growth And Development Characteristics

In this study,straw decomposition rate,nutrient(P,N,C)release rate,main soil microorganisms,enzyme activity in rhizosphere soil and physiological characteristics of maize were studied under different ways of returning corn straw to the field.The main conclusions are as follows:1)The decomposition rate and nutrient release rate of corn straw can be improved by deep burying and returning.After decomposing for 150 days,the release rate of organic carbon was the highest among nitrogen,phosphorus and carbon.The nutrient release rate of corn straw was69.9%-77.9%(C),37.6%-45.7%(N)and 63.7%-65.2%(P)for mulching and deep burying,respectively.2)The quantity of bacteria,actinomycetes and major microbial physiological groups(nitrogen fixing bacteria,nitrifying bacteria and ammoniating bacteria)in rhizosphere soil and the enzyme activity in rhizosphere soil will be increased,but the quantity of fungi will be reduced.The diversity and relative abundance of bacteria in the field of deep burying and returning straw were higher than those in the field of straw mulching,among which the relative abundance of Sphingomonas,Marseilles,Nocardia,oxyphilia,lysobacteria and blastomonas in the field of deep burying and surface covering was higher than that in the control;the diversity and relative abundance of fungi in the field of deep burying straw could be increased more than that in the field of straw mulching The relative abundances of Pythium,Mortierella,Chaetomium,Gibberella and Chaetomium were all higher than those of the control.The deep burying of straw could enhance the plant resistance,plant height and dry weight.The number of soil functional microbial community was increased by deep burying and surface covering of corn straw.3)Under the two ways of returning to the field,the deep burying of corn straw could significantly enhance the activity of root system and the activities of protective enzymes(catalase,peroxidase and superoxide dismutase)of root,stem and leaf.There was no significant effect of different straw returning methods on MDA content of rhizome and leaf.4)The root dry weight and dry matter accumulation of deep burying corn straw were greater than that of mulching at all stages of corn growth.Compared with straw mulching,straw deep burying can significantly increase the leaf area index of maize.5)The photosynthetic gas exchange parameters(Pn,Tr,Gs)and the maximum photochemical efficiency(Fv / Fm)of the leaves at the ear position were higher than those of the mulching.The content of Chl in leaves was significantly increased when straw was deeply buried.