为探究草鱼混养与单养两种养殖模式的温室气体昼夜变化特征与影响因素,采用静态暗箱-气相色谱 仪法对2个草鱼养殖池塘的水-气界面CO2 、甲烷(CH4 )和氧化亚氮(N2 O)通量进行了24h观测。 结果显 示:草鱼混养和单养CO2 通量的昼夜变化范围分别为(-119.03±76.25)~(59.79±52.19)和(-199. 88± 163. 25) ~(186. 64±48. 06)mg/ (m2·h),CH4 通量范围分别为(1. 81±2. 07) ~(7. 25±7. 06)和(-11. 75± 14. 38) ~(17. 77±14. 84)mg/ (m2·h),N2 O 通量范围分别为(24.4±16.4)~(77. 4±34. 7)和(43. 8±12. 8)~ (165. 7±122. 2)μg/ (m2·h)。 草鱼混养的 CO2 、CH4 和 N2 O 日平均排放量均低于单养模式,其中,N2 O的排 放达到了极显著水平,混养模式使草鱼养殖的CO2 、CH4 和N2 O平均排放通量分别下降了56.60%、5.03%和 46. 96%。 整体上两种养殖模式均为温室气体排放源;三种温室气体排放均具有昼低夜高的特征,两种模式 的CO2 通量昼夜差异均达到极显著水平,草鱼单养CH4 排放的昼夜差异达到显著水平,两种养殖模式N2 O 排放的昼夜差异均不显著;驱动混养模式温室气体排放的主要环境因子为氧化还原电位(Eh)、化学需氧量 (COD)、总有机碳(TOC)和气压,单养模式的主要驱动因素为风速、气压和泥温;混养能降低草鱼池塘养殖 的温室气体排放,具有显著的碳减排效益。

To explore the diurnal variation characteristics and influencing factors of greenhouse gases in grass carp polyculture and monoculture ponds,24-hour monitoring was carried out to measure the CO2 ,(Methane) CH4 ,and (Nitrous oxide)N2 O fluxes at the water-air interface of two grass carp culture ponds using static chamber-GC method.The study indicated that the diurnal variation range of CO2 fluxes were (-119.03± 76.25)-(59.79±52.19) mg/(m2·h) in the polyculture and (-199.88±163.25)-(186.64±48.06) mg/(m2·h) in the monoculture.The range of CH4 fluxes were (1.81±2.07)-(7.25±7.06) and (-11.75± 14.38)-(17.77±14.84)mg/(m2·h).The range of N2 O fluxes were(24.4±16.4)-(77.4±34.7) and (43.8±12.8)-(165.7±122.2)μg/(m2·h).The average daily emission fluxes in the polyculture of CO2 , CH4 and N2 O were lower than those in the monoculture.Among them,N2 O emission reached an extremely significant level.The polyculture led to reductions in the average emission fluxes of CO2 ,CH4 and N2 O from grass carp ponds by 56.60%,5.03%,and 46.96%.The two farming modes were both greenhouse gas emission sources.The emissions of the three greenhouse gases were lower during the day and higher at night.The diurnal difference in CO2 flux between the two modes reached an extremely significant level.The diurnal difference in CH4 emission from monoculture reached a significant level.There was no significant difference between the two modes of N2 O emission.The major environmental influencing factors of greenhouse gas emissions in polyculture were (Oxidation-reduction Potential)Eh,(Chemical Oxygen Demand)COD,(Total Organic Carbon)TOC,and air pressure,while those in the monoculture were wind speed,air pressure,and mud temperature.The polyculture can reduce greenhouse gas emissions from grass carp ponds,which has a significant carbon emission reduction effect.