Subsequent Effects Of Slag And Biochar Application On Soil Carbon Pools And Soil Microorganisms In Paddy Fields

Paddy fields are important food production bases,and their productivity has an important impact on human survival.Soil organic matter is the core of soil fertility and the basis for the sustainable production of rice.The research group used the paddy field in Fuzhou Plain as the experimental area.In the previous research,it was found that the application of biochar and slag in rice fields has certain carbon sequestration and emission reduction effects.In order to further understand the subsequent effects of the application treatment,in this study,biochar,slag,biochar+slag?mixed application?treatment was applied to rice fields in 2015,and no treatment was applied as a control.Two years later?2017?,soil carbon pool composition,physicochemical properties,microbial population,microbial diversity and community composition were measured,and Pearson correlation was used to analyze environmental factors and activated carbon components and microbial population.The relationship between carbon components,environmental factors and flora was analyzed by CCA.The subsequent effects of applied treatment on the microbial community composition in paddy soil and the mechanism of soil carbon sequestration and organic matter maintenance,improve the agricultural production management model in China,clarify the effective time of waste application,and achieve carbon sequestration in paddy soil.The row has important practical significance.The main findings are as follows:1.After 2 years of application of slag and biochar,the emission flux of CO₂ and CH₄can still be reduced.The application treatment increases the N₂O emission of early rice soil and reduces the N₂O emission of late rice soil.The application treatment has significantly reduced the global warming potential of greenhouse gases.CO₂ was significantly positively correlated with soil bulk density and soil temperature conductivity,and significantly negatively correlated with pH and conductivity.CH₄ is significantly positively correlated with soil temperature and conductivity.N₂O was significantly positively correlated with pH and significantly negatively correlated with soil temperature and bulk density.2.The contents of SOC,EOC,DOC and MBC in different applied treatments were ranged from 15.36-16.80 g·kg^-1,22.75-37.16 mg·kg^-1,4.40-4.86 g·kg^-1,289.04-327.66mg·kg^-1.After 2 years of application and mixing of slag and biochar,the SOC content of the treatment group was significantly higher than that of the control group.The DOC,EOC and MBC levels were not significantly different from the control group.3.The application treatment has different effects on the number of bacteria and the number of fungi in paddy soils in different rice seasons and different growing seasons.From the average of the number of bacteria in the early and late rice jointing and maturity stages,the number of bacteria treated by slag,biochar and mixed application was higher than that of the control group,but the number of fungi was not significantly different from the control group.4.Different application treatments reduced the bacterial diversity of early rice soil and increased the bacterial diversity of late rice soil.The diversity of bacteria.The soil bacteria in paddy fields were mainly Proteobacteria,Bacteroidetes,Firmicutes,Acidobacteria,and Actinobacteria.The dominant genus of early paddy was Sphingomonas and Massilia.The dominant genus of late paddy was Sphingomonas and Clostridium_sensu_stricto₁.5.Different application treatments reduced the fungal diversity of early rice soil and increased the fungal diversity of late rice soil.Paddy soil fungi are mainly Ascomycota and Chytridiomycota Basidiomycota.The dominant genus of early paddy was Paranamyces,Emericellopsis,and Fusarium.The dominant genus of late paddy was Emericellopsis and Fusarium.6.In the early paddy growing season,slag and biochar application treatment reduced the number of methane producing bacteria,and the mixed application increased the number of methane producing bacteria.In the late paddy growing season,each applied treatment increased the number of methane producing bacteria.7.Both early and late rice application treatment increased the relative abundance of Candidatus methanoperedens.The relative abundance of Methanosarcina in early rice soil was higher than that in late rice soil.The relative abundance of Methanosaeta was less than that.Late rice soil.The relative abundance of Methanobacterium was significantly positively correlated with soil pH of paddy field?P<0.01?.The relative abundance of Methanobacterium and Methanoculleus was significantly negatively correlated with soil temperature?P<0.01?.