Effects Of Continuous Application Of Biochar-based Fertilizer On Nitrification And Ammonia-oxidizing Microorganism

The research is depend on the experimental field in Shenyang Agricultural University Peanut Biochar-based Experiment,using the soil and plants of peanut growth period in 2018 and using field test,indoor culture test,high-throughput sequencing and other different test methods.Explore the effect of application of biochar-based fertilizer of peanut?hereinafter referred to as"biochar-based fertilizer"?on soil nitrification intensity,nitrification potential,plant nitrogen uptake,abundance and community structure of AOA,AOB through the treatments:control?CK?;low biochar?C15?;high biochar?C50?;chemical fertilizer?NPK?and biochar-based fertilizer?BBF?.Therefore,it provides theoretical basis for improving soil,weakening soil nitrification,reducing nitrogen loss and increasing peanut yield.After testing,the following conclusions are drawn in this paper:?1?During the growth of peanut,the peak of NH₄⁺-N appeared in the seedling stage,while the peak of NO₃^--N appeared in the flowering stage.Treatments under different amount of fertilizer showed different NH₄⁺-N concentrations in the same growth period,wherein the N concentration under NPK treatment was significantly higher than that under other treatments in each growth period of peanut,and the N concentration in surface soil at the pod setting stage was 2.3 times higher than that under CK treatment.The application of bichar-based fertilizer will increase the NH₄⁺-N content in soil,increase the accumulation of NH₄⁺-N in soil,slow down the NO₃^--N leaching in deep soil,reduce the nitrification potential of soil,and reduce the accumulation and loss of a large amount of NH₄⁺-N caused by nitrification,thus reducing the loss of soil N.?2?Continuous application of biochar and biochar-based fertilizer can significantly increase the C content of soil microbial biomass,as well as the N content of deeper soil microbial biomass.The application of biochar and biochar-based fertilizer can lead soil microbial biomass C/N ratio increasing.The activity of soil urease was significantly correlated with soil microbial biomass C/N ratio.?3?Under the conditions of this experiment,the abundance of amo A genes in AOA and AOB was in range of 1.28×10⁶?6.16×10⁶ and 2.73×10⁴?1.39×10⁵copies·g^-1dry soil.Among them,the number of amo A genes in AOA is 1?2 orders of magnitude higher than AOB.The BBF treatment's copy number of amo A gene from AOA was 1.28×10⁶,which was significantly higher than other treatments.Continuous application of biochar and biochar based fertilizer had significant effects on the gene copy numbers of ammonia-oxidizing microorganisms.The amo A gene copy number of AOA and AOB and AOA/AOB ratio were significantly increased with the increase of biochar input.Biochar-based fertilizer can significantly increased the copy number of AOA amo A gene,but had no significant effect on the abundance of AOB gene,and could relatively reduce the copy number of AOA amo A gene.?4?Thaumarchaeota and Crenarchaerota were the predominant AOA phyla and Proteobacteria was the main AOB phyla which accounted for 53.21%and 78.08%of the total AOA and AOB amo A gene reads,respectively.The dominant bacteria of AOB were verified by Nitrosospira.Treatment using NPK as unic fertilizer can increase the relative abundance of Nitrosospira in soil.Venn diagram indicated that manure fertilization rate had a stronger effect on the OTU number of AOB amo A gene than that of AOA in different treatments,but it slightly altered the proportion of shared AOA and AOB amo A gene reads.Soil physical and chemical properties have effects on AOA and AOB community structure,among which ammonium nitrogen content and the activity of soil U?SE have significant effects on soil ammonia-oxidizing microbial community structure.Biochar basal plowing can improve soil microbial nitrification of ammonia oxidation in the relative abundance of the dominant fungi in the process,but relative to the application of chemical fertilizer NPK treatment showed obvious difference,can further readjustment of ammonia oxidation on the nitrification inhibition effect.?5?The N fixation and N accumulation of peanut root nodule were significantly increased by applying biochar and biochar-based fertilizer.The accumulation of N increaced follow the application of biochar.The dry matter accumulation in different treatments was as follows:BBF>C50>NPK>C15>CK.Continuous application of biochar-based fertilizer can highup the accumulation of dry matter in each growth period of peanut,thus significantly increasing the yield of peanut.