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污染控制技术及原理

The effects of chlorothalonil on nitrous oxide and methane emissions from soils under anaerobic conditions

摘要：在密闭、淹水、充N₂的严格厌氧条件下对土壤进行了14d的培养试验,研究了杀菌剂百菌清在添加水平为田间施用量(FR)(5.5mg·kg^-1),20倍(20FR)和40倍田间施用量(40FR)时对强酸性、酸性、中性和碱性土壤N₂O和CH₄排放的影响.结果表明,20FR和40FR的百菌清能够显著促进N₂O向N₂的还原,降低N₂O排放,在酸性、中性和碱性土壤中培养14d后,对照处理的N₂O排放量为0.076～0.46mg·kg^-1,而20FR和40FR处理的N₂O排放量为0.004～0.06mg·kg^-1,降低了1个数量级.反硝化作用和有机氮矿化作用强的土壤中,百菌清减少N₂O排放作用更明显.反硝化底物NO₃^-的存在对CH₄的产生与排放具有显著的抑制作用.在加入百菌清未对NO₃^-浓度产生显著影响的土壤中,百菌清对CH₄排放量没有明显影响,在对NO₃^-浓度产生显著影响的土壤中,CH₄排放量随着NO₃^-的增加而减少,说明百菌清可能通过影响反硝化过程中NO₃^-的消耗而影响CH₄排放.

Abstract：The effects of the fungicide chlorothalonil on nitrous oxide and methane emissions from strongly acidic,acidic,neutral and alkaline soils were investigated in laboratory anaerobic incubation tests. The tests were performed at 25℃ with addition rates of 5.5 mg·kg^-1 A. I. (field rate,FR),20 (20FR) and 40 times (40FR) field rate. The results indicated that chlorothalonil at levels of 20FR and 40FR promoted the reduction of N₂O to N₂,thus decreasing N₂O emission significantly with the strongest effect in acidic,neutral and alkaline soils. N₂O production ranged from 0.076～0.46 mg·kg^-1 in the control soils and 0.004～0.06 mg·kg^-1 in 20FR and 40FR treatments at the end of incubation. The stronger the denitrification activities and organic nitrogen mineralization in soils,the more chlorothalonil mitigated N₂O emission. For the soils in which denitrification was not significantly affected by chlorothalonil,no significant differences in CH₄ emissions were observed at different chlorothalonil addition rates. However,CH₄ emissions decreased at higher rates of chlorothalonil addition in the soils in which denitrification was significantly affected by chlorothalonil. Because the substrate NO₃^- of denitrification inhibited CH₄ production and emission significantly,the inhibition effect of chlorothalonil on CH₄ emission probably resulted from its inhibition of NO₃^- denitrification.