Effect Of No-tillage Mulching Organic Fertilizer Application On Crop Yield And Soil Microbial Community Composition

As an important conservation tillage measure in farmland management,no-tillage not only can store water and protect the soil,optimize the soil environment,but also play an important role in maintaining the composition and diversity of soil microbial community structure.Terefore,in this paper,farmland soil ecosvstem is taken as the research object.Four soil treatments were selected including no-tillage and straw mulching without organic fertilizer application(NC).no-tillage and straw mulching with organic fertilizer application(NF),traditional tillage and no-mulching without organic fertilizer application(TC)and traditional tillage and no-mulching with organic fertilizer application(TF):By using Illumina Miseq high-throughput sequencing platform and phospholipid fatty acids(PLFAs)analysis methods.Soil microbial biomass and bacterial 16S rRNA gene and fungal ITS region sene Nere determined respectively to study the changes of soil physicochemical and biological characters,microbial community structure,fungi and bacterial diversity in different treatments.The main results are as follows:(1)C ompared with TC treatment,NF treatment can significantly reduce soil pH,increase soil total nitrogen,and affect soil carbon nitrogen ratio.Soil microbial biomass carbon will be significantly affected when the two factors of cultivation and ferilization interact.(2)According to the three-years experiment of no-tillage mulching and organic fertilizer application,different tillage measures have different effects on crop yield.In the first year of no-tillage(2016),there was no significant difference in crop yield between treatments,while in the second year and the third year(2017 and 2018).the crop yield under TF treatment reached the highest under TF treatment,followed by TC.Above.TF treatment was more conducive to promoting the increase of crop vield.(3)A fter 3 years of no-tillage application of organic fertilizer,the biomass of soil microbial community changed significantly.Compared with NF treatment.TF treatment significantly increased the biomass of soil fungi,bacteria,actinoniycetes and gram-positive(G+)(P<0.05).soil AM fungi biomas ratios of 16:1?5c neutral lipid(NLFA)to 16:1?5c phospholipid lipid(PLFA)significantly increased(P<0.05).(4)A total of 27 phylum bacteria and 9 phylum fungi were obtained from soil samples of winter wheat.Among them,the dominant bacteria were Actinobacteria,Chlorobacteria and Proteobacteria,accounting for 82.40%of the total relative abundance,while the dominant fungi were Ascomycota,Zygomycota and Basidiomycota.accounting for 90.23%of the total relative abundance.(5)The results of multivariate analysis showed that the content of soil phosphorus directly affected the relative abundance of Actinomycetes and Chlorobacteria.while available potassium and Carbon nitrogen ration(C/N)were the main factors affecting the relative abundance of Proteobacteria and Acidophilus.The soil microbial biomass carbon was significantly positively correlated with Basidiomycetes and Zygomycetes.The soil organic carbon content was the main factor driving the distribution of Ascomycota community.