为有效控制沼液贮存过程中的温室效应，以锯末为覆盖材料，探究在沼液贮存过程中不同覆盖厚度(2、4 cm和6cm)对氨气(NH3)和温室气体[氧化亚氮(N2O)和甲烷(CH4)]排放、微生物群落结构的影响，以综合温室效应为评价指标，筛选出经济有效的降低温室效应的覆盖厚度。结果表明:锯末2、4 cm和6cm覆盖对NH3减排率分别为37。5%、19。4%和24。2%;对N2O减排率分别为-84。7%、41。9%和44。6%;对CH4减排率分别为-18。7%、16。3%和23。7%。从微生物群落结构来看，各覆盖处理均降低了与碳、氮循环相关的微生物丰度，减弱了沼液内部有机质的分解和温室气体的产生。然而，随着覆盖厚度的增加，锯末材料沉降腐解增强，对碳、氮循环功能削弱效果逐渐降低，但是对气体逸出的吸附和阻碍作用仍然随着覆盖厚度的增加而增强，沼液产生的总CO2当量也逐渐减小。综合各种温室效应贡献气体排放情况，不覆盖处理和锯末2、4、6 cm覆盖处理的单位体积沼液35d产生的总CO2当量分别为10。2、13。0、7。9、7。3 g CO2e·L-1，因此，采用4cm厚的锯末覆盖沼液是较为经济有效的覆盖方案。
Effects of sawdust covering thickness on greenhouse effect during biogas slurry storage
To effectively control the greenhouse effect in the storage process of biogas slurry,we used sawdust as the covering material and explored the effects of different covering thicknesses(2,4 cm,and 6 cm)on emissions of ammonia(NH3)and greenhouse gases[nitrous oxide(N2O)and methane(CH4)]and microbial community structure in the storage process of biogas slurry produced by fermentation of black membrane biogas digester in dairy farms.Using the comprehensive greenhouse effect as an evaluation index,appropriate covering thickness was determined.The results demonstrated that the NH3 emission reduction rates of 2,4 cm,and 6 cm sawdust covering treatments were 37.5%,19.4%,and 24.2%,respectively.The emission reduction rates of N2O were-84.7%,41.9%,and 44.6%,respectively.The emission reduction rates of CH4 were-18.7%,16.3%,and 23.7%,respectively.From the microbial community structure perspective,all mulch treatments reduced the abundance of microorganisms related to carbon and nitrogen cycles and weakened the organic matter decomposition and the greenhouse gas production in biogas slurry.However,with the increase of the covering thickness,the sedimentation and decomposition of sawdust materials were enhanced,and the weakening effects of carbon and nitrogen cycling were gradually reduced.However,the adsorption and hindering effects of gas escaping were still enhanced with the increase of covering thickness,and the total CO2 equivalent produced by biogas slurry was gradually reduced.Taking into account all the greenhouse gas emissions,The total CO2 equivalences produced by a unit volume of biogas slurry in 35 d were 10.2,13.0,7.9 g CO2e·L-1,and 7.3 g CO2e·L-1,respectively,in the untreated treatment,2,4 cm,and 6 cm sawdust covering treatment.Therefore,it is more economical and effective to use sawdust with a 4 cm covering thickness to cover biogas slurry.
sawdustbiogas slurrycovering thicknessesgreenhouse effectmicrobial community structure
万方数据
维普
