牛粪不同堆肥模式对温室气体排放的影响

采用静态箱-气相色谱法研究了自然状态下牛粪(C)、牛粪+秸秆(CSt)、牛粪+土(CSo)、牛粪+秸秆+土(CSt So)4种堆肥模式对温室气体排放的影响,以期为温室气体减排和堆肥模式优化提供参考。结果表明:堆肥期间堆温和温室内气温随时间推进均呈升—降—升的趋势,同一观测时间点气温高于堆温,总体上CSt、CSt So处理的堆温略高于C、CSo处理,表明加入秸秆具有提高堆温的效果。随时间推进,C处理的CO_2、CH_4和N_2O排放通量总体均呈增加的趋势,第6~7周排放通量较大;CSt、CSo、CSt So处理的3种温室气体排放通量总体均呈先升后降的趋势,CO_2和CH_4排放通量最大值总体出现在第2周,N_2O排放通量在第5~6周时较大。CO_2平均排放通量表现为CStCSt SoCSoC,除C处理与CSo处理无显著差异外,其他处理间差异显著;CH_4平均排放通量表现为CCStCSt SoCSo,C处理与CSt、CSo、CSt So处理之间及CSt、CSo处理之间差异显著;N_2O平均排放通量表现为CSoCStCSt SoC,CSo处理与C处理差异显著。CSt、CSo、CSt So处理的全球增温潜势(GWP)分别是C处理的3.25、2.61、2.59倍,主要是由于CSt、CSo、CSt So处理的CO_2和N_2O排放总量显著高于C处理,其对GWP的贡献率均高达97%以上。综合考虑广大农村堆料实际组分及温室气体减排,建议采用CSt So堆肥模式,但应适当增加牛粪和土的用量。

Effect of Different Composting Models of Cattle Manure on Greenhouse Gases Emission

The effect of four composting treatments,such as cattle manure (C),cattle manure and straw (CSt),cattle manure and soil(CSo),cattle manure,straw and soil(CStSo) on greenhouse gases(GHGs) emission were studied by using the static chamber-gas chromatograph techniques,so as to provide a reference for GHGs emission reduction and composting model optimization.The results showed compost temperature and air temperature in greenhouse both took on rising-descending-rising trend during composting period.But the air temperature was higher than compost temperature at the same observation time.Overall,the compost temperature of CSt,CStSo treatments were higher than those of C,CSo treatments,indicating that adding wheat straw could increase the compost temperature.The emission flux of carbon dioxide (CO2),methane(CH4),and nitrous oxide(N2O) under C treatment increased with the time going on,and the maximum value appeared between the sixth and seventh week.The trend of GHGs emission flux of CSt,CSo,and CStSo treatments first increased and then declined,the maximum emission flux of CO2 and CH4 appeared on the second week,the maximum emission flux of N2O was observed during the fifth and sixth week.The order of average CO2 emission flux was CSt ＞ CStSo ＞ CSo ＞ C,among which all treatments were significantly different except C and CSo treatments.The order of average CH4emission flux was C ＞ CSt ＞ CStSo ＞ CSo,among which CSt,CSo,CStSo treatments were significantly different with C treatment,and CSt treatment was also significantly different with CSo treatment.The order of average N2O emission flux was CSo ＞ CSt ＞ CStSo ＞ C,among which C and CSo treatments were significantly different.The global warming potential(GWP) of CSt,CSo,and CStSo treatments were 3.25,2.61,and 2.59 times of C treatment respectively,which showed that cattle manure compost gave out the lowest amount of GHGs.Based on the GHGs emission amount and realistic compost constituent,CStSo treatment was recommended to apply after increasing the ratio of cattle manure and soil.