摘要
选取湖南典型红壤双季稻田为研究对象,采用静态箱—气相色谱法对不施肥对照(CK)、常规施化肥(NPK)、新鲜稻草与化肥配施(RS+NPK1)、菌渣与化肥配施(MR+NPK1)、新鲜牛粪与化肥配施(CD+NPK2)和沼渣与化肥配施(BD+NPK2)等6个处理的CH4和N2O排放通量进行为期一年的观测(早稻、晚稻和休闲期),研究排放特征与驱动因素。结果表明,不同处理的CH4排放均表现出"早稻生长期少,晚稻生长期多,休闲期弱"的特点,而N2O排放主要发生在水稻生长期内(78%以上),休闲期内排放较少。NPK的CH4排放比CK增加了35%,差异不显著(P>0.05,P是拒绝原假设的犯错概率)。有机无机配施处理中,RS+NPK1和CD+NPK2的CH4全年累计排放量分别是MR+NPK1和BD+NPK2的2.44和2.45倍(P<0.05),但后者的N2O全年累计排放量分别比前者提高了59%和102%(P>0.05)。与单施化肥相比,有机无机配施使稻田氮肥N2O-N直接排放系数降低45%~80%。相关环境因素分析表明,水、热变化是驱动稻田CH4排放季节变化的主要因素。本研究未发现水分变化与N2O排放通量之间存在直接联系,而且CH4和N2O在排放时间上不存在消长关系。CH4和N2O的整体温室效应表明,CH4是当地双季稻田的主要温室气体。采用腐熟后的菌渣和沼渣代替新鲜的稻草和牛粪还田可以使稻田CH4排放量降低约60%,CH4和N2O的整体温室效应降低约50%,而稻谷产量保持不变。
Annual CH4 and N2O emission fluxes were measured from double rice cropping systems under six fertilization treatments by using the method of static chamber-gas chromatograph techniques.The different treatments including non-fertilizer(CK),conventional chemical fertilizers(NPK),fresh rice straw with chemical fertilizers(RS+NPK1),mushroom residue with chemical fertilizers(MR+NPK1),fresh cow dung with chemical fertilizers(CD+NPK2),and biogas digestion with chemical fertilizers(BD+NPK2) were dedicated to this experiment in order to study the characteristics of CH4 and N2O emissions and the relationship between gas emission fluxes and related environmental factors.The results showed that,seasonal variation of CH4 emission fluxes under different treatments displayed the same trend,which can be described as "lower in early rice growing period,higher in late rice growing stage,and negligible in the fallow season ".The majority of N2O emissions(more than 78%) occurred in rice growing periods,and small amounts of N2O emission occurred in the fallow season.Although the annual accumulated CH4 emission amount for NPK was increased by 35% compared with CK,the difference between them was not significant at 0.05 level.Among different treatments of organic and mineral fertilizers,the annual accumulated CH4 emission amount for RS+NPK1 was 2.44 times more than that for MR+NPK1(P0.05,P is the significance level),while the annual N2O emission amount for the latter was 59% higher than that for the former(P0.05).The annual accumulated CH4 emission amount for CD+NPK2 was 2.45 times more than that for BD+NPK2(P0.05),but the annual N2O emission amount for the latter increased by 102% compared with CD+NPK2(P0.05).The fertilizer-induced direct N2O emission factor(E) was reduced by 45%-80% under the treatments of combined application of chemical and organic fertilizers in paddy fields compared to NPK.In this analysis,water status and temperature were main driving factors which affected the seasonal variation of CH4 emission fluxes.However,N2O emission fluxes did not have direct relation with water status in double rice paddies and a temporal trade-off relationship between the two gas emission fluxes was not observed in this study.CH4 was the dominant greenhouse gas which contributed more than 75% to the integrated global warming potential of CH4 and N2O emissions in local double rice fields.By using composted mushroom residue and biogas digestion to substitute for fresh rice straw and cow dung for returning fields,CH4 emission and integrated global warming potential of CH4 and N2O emissions reduced by approximately 60% and 50%,respectively,and the grain yield will not be affected.
出处
《大气科学》
CSCD
北大核心
2011年第4期707-720,共14页
Chinese Journal of Atmospheric Sciences
基金
国家科技支撑计划课题2008BAD95B13
2008BAD95B02
国家973计划项目2010CB951302
"十一五"支撑计划项目2007BAD89B11
关键词
稻田
CH4
N2O
施肥
rice field
CH4
N2O
fertilization