| Red soil in the subtropical dryland of southern China is seriously degraded due to subtropical monsoon climate and human factors,low soil fertility,reduced biodiversity and gradually acidified.In response to this phenomenon,organic livestock manure(organic fertilizer)in dryland red soil can effectively solve these problems.However,the application of organic fertilizers will increase the CH4 and N2 O emissions of the soil,add biochar to the organic fertilizer(animal manure)compost,and apply this biochar-organic compost mixture to the soil to increase crop yield and reduce CH4 and N2 O emissions have important practical value and application prospects.In view of the relatively large influence of materials on biochar,the greenhouse gas emission characteristics of red soil in dryland under the influence of different materials bio-carbon-organic compost are discussed.This study was carried out in the form of indoor culture to investigate the greenhouse gas emission characteristics of red soil in dryland under the influence of biomass-carbon fertilizer composting with different materials.The experimental treatment design is as follows: Experiment 1: Experiment 1:(1)Control,denoted as CK.(2)Biochar charcoal(9.53 g·kg-1)made of rice straw was applied to the soil and recorded as R.(3)Biochar charcoal(9.67 g·kg-1)made of corn straw was applied to the soil and recorded as C.(4)Biochar charcoal(9.67 g·kg-1)made of wheat straw was applied to the soil and recorded as W.Experiment 2:(1)Applying pig manure compost(100.67 g·kg-1)to the soil,recorded as M.(2)applying rice straw into biomass charcoal-pig manure compost(125.33 g·kg-1)Soil,recorded as RM.(3),corn stalks made into biomass charcoal-pig manure compost(136.67 g · kg-1)applied to the soil,recorded as CM.(4)wheat straw into biomass charcoal-pig manure compost(135.33 g·kg-1)was applied to the soil and recorded as WM.The main findings are as follows:1.Adding biomass carbon significantly reduces soil greenhouse gas emissions.Compared with CK,the cumulative emission fluxes of N2 O,CH4 and CO2 in R,C and W treatments decreased by 51.4%~59.8%,34.8%~78.8% and 12.6%~27.3%,respectively.The soils under C and W treatment had the lowest GWP,and the best effect on greenhouse gas emission reduction in red soil in dryland,but there was no significant difference between the two.Adding biomass carbon-organic fertilizer compost significantly reduces soilN2O and CO2 emissions.Compared with M,the cumulative emission fluxes of N2 O and CO2 in soil treated by RM,CM and WM decreased by 56.5%~72.3% and 31.3%~40%,respectively.CM treatment of dryland red soil has the lowest GWP,and the best effect on greenhouse gas emission reduction in dryland red soil.2.Biomass carbon significantly increases soil catalase activity and dehydrogenase activity.Compared with CK,it increased by 15.7%~25.8% and 12.7%~34.7%,respectively.Among them,W treatment had the most improvement of soil catalase activity,and R treatment had the most improvement of soil dehydrogenase activity.C and W treatment significantly increased soil urease activity,but there was no significant difference between the two,and the effect of R treatment on urease was not obvious.R treatment significantly increased soil sucrase activity,which was 6.1% higher than CK,while C and W treatment had no significant effect on sucrase.Biomass carbon-organic fertilizer compost significantly reduced soil urease activity,which was 22.4%~47.3% lower than M treatment;RM treatment increased soil sucrase activity,while CM and WM treatment reduced soil sucrase activity;RM and CM significantly increased soil dehydrogenase activity,which was 12.7% and 15.7% higher than that of M,while WM treatment decreased soil dehydrogenase activity,which was 16.3% lower than M.RM,CM,and WM treatments increased soil catalase activity by 17.1% to 22.4% compared to M.3.Biomass carbon increases soil pH,DOC,organic carbon,total nitrogen and C/N ratio,reducing soil DON,nitrate nitrogen and inorganic nitrogen R treatment significantly increased soil MBC and ammonium nitrogen content,W treatment significantly increased soil MBC content,significantly reduced soil MBN content.Biomass carbon-organic fertilizer composting reduced soil MBC content and increased soil DON,nitrate nitrogen,inorganic nitrogen,p H,total organic carbon and C/N ratio.There was no significant difference between MBN,DOC,ammonium nitrogen and total nitrogen in soil treated with biochar-organic fertilizer composting and organic fertilizer composting.4.Biomass charcoal increased soil total PLFAs content by 6.3%~7.9% compared with CK,but biomass charcoal had no effect on the relative abundance of characteristic microbiota.Compared with M,biomass carbon-organic compost reduced the total PLFAs content of soil by 10.2%~23.3%,reduced the relative abundance of soil fungi and increased the relative abundance of soil bacteria.In conclusion,biomass charcoal,when applied to upland red soil,affects soil physical and chemical properties,enzyme activities and microorganisms,and significantly reduces soil greenhouse gas emission flux.Compared with organic compost,biomass carbon-organic compost has a significant effect on greenhouse gas emission reduction after being applied into soil,among which biomass carbon-organic compost made from corn has the best effect on greenhouse gas emission reduction in upland red soil. |
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