沼液施用对土壤温室气体排放的影响

采用静态箱-气相色谱法，于2010年7月（夏季）、2011年3月（冬季）进行了不同沼液施用量对土壤二氧化碳（CO2），甲烷（CH4）和氧化亚氮（N2O）气体排放影响的研究。试验期间，沼液施用设为大量施沼液（夏季为28.36 gm-2，冬季为1.94 gm-2），正常施沼液（夏季为9.45 gm-2，冬季为0.65 gm-2）和不施沼液等3个水平。结果表明:①夏季或冬季，处理对土壤二氧化碳排放影响均不显著。②夏季沼液施用8 h内，处理间对土壤甲烷排放具极显著差异（P＜0.001)，其中大量施沼液时通量最大为3.98 mgm－2h－1；正常施沼液时通量最大为1.25 mgm－2h－1，8 h后处理间无显著差异（P＞0.05）。冬季在大量施沼液时，初期土壤甲烷排放通量明显高于正常施沼液及不施沼液，最大为0.28 mgm－2h－1；随后处理间土壤甲烷排放通量无显著差异。③夏季沼液施用20 h内，处理间对土壤氧化亚氮排放具极显著差异（P＜0.001），最大值达1 641 gm－2h－1；处理间呈显著差异（P＜0.05），大量施沼液、正常施沼液和不施沼液时土壤氧化亚氮排放通量分别为224～349，70～137，33～57 gm－2h－1；冬季则处理间土壤氧化亚氮排放无显著差异。图3参19

Biogas slurry application with greenhouse gas emissions in agricultural soils

To determine the effects of biogas slurry application on greenhouse gas emissions （GGE），including CO₂，CH₄，and N₂O，in agricultural soil，a closed-chamber，gas chromatography-based system were used in July 2010 （summer） and March 2011 （winter）. Three treatments with 3 replications were carried out：no （ck），normal （9.45 g·m^－2 in summer，and 0.65 g·m^－2 in winter），and heavy （28.36 g·m^－2 in summer，and 1.94 g·m^－2 in winter） biogas slurry applications. Two-way ANOVA analysis was used to test the significance. Results showed （1） no significant differences in CO₂ emissions among treatments. （2）For CH₄ emissions in summer within the first 8 h of biogas slurry application, the heavy application treatment was significantly greater （P＜0.001) than the other two treatments with a maximum emission flux of 3.98 mg·m^-2·h^-1 in the heavy, 1.25 mg·m^-2·h^-1 in the normal，and 0.28 mg·m^－2·h^－1 in ck；however，after 8 h there were no significant differences. （3） N₂O emissions in summer within the first 20 h after biogas slurry application, revealed significant differences （P＜0.001） with a maximum emission flux of 1 641 μg·m^－2·h^－1 in the heavy application treatment；after 20 h，significant differences （P＜0.05） between the treatments continued with the N₂O emission fluxes of 224－349 μg·m^－2·h^－1 for heavy，70－137 μg·m^－2·h^－1 for normal，and 33.81－57.06 μg·m^－2·h^－1 for ck. No significant differences in N₂O emissions were found between the treatments in winter. These results could provide helpful information for environmental risk assessments with biogas slurry application, especially with effects on GGE. ［Ch，3 fig. 19 ref.］