采用静态暗箱-气相色谱法对太湖地区水稻生态系统甲烷(CH4)排放进行田间原位观测,共设置无氮(NN)、常规(FP)、增产增效(YE)(增产10%~15%,氮肥利用率(NUE)提高20%~30%)、再增产(HY)(增产30%~40%)、再增效(HE)(NUE提高30%~50%)和保产增效(IE)(产量不变,NUE提高20%~30%)六种不同的栽培模式。结果表明,稻田CH4排放具有明显的季节变化,在水稻生长期间先升高后降低,从水稻移栽至抽穗期CH4排放通量占全生育期的93%~98%。不同栽培模式间CH。累积排放量差异屁著(P〈0.05),HY处理高达258.8kghm-2,显著高于未施有机肥各处理;单位稻谷产量CH4排放量差异不显著,平均为CO2 0.60kgkg-1,提高稻谷产量的模式不会显著影响CH4排放;其中YE处理单位稻谷产量CH4排放量最低,为CO2,0.49kgkg-1,可以同时实现增产、增效和减排,值得推广。
Methane fluxes from rice fields in the Taihu Lake Region were studied using static-chamber/gas chromatography. In-situ observation was carried out in paddy fields different in treatment or cultivation pattern, separately, i. e. Treatments NN (no N control), FP (farmer's practice), YE (10%- 15% higher in yield and 20%-30% higher in N use efficiency), HY (30%-40% higher in yield), HE (30%-50% higher in N use efficiency), and IE (currently integrated management for the same as FP in yield and 20% - 30% higher in NUE). It was found that distinctive seasonal variation existed of methane emission from rice fields. Methane fluxes increased after transplanting peaking at the vegetative growth stage early or late depending on treatments and then declined rapidly after mid-season drainage. The cumulative methane emission observed during the period from transplanting to the heading stage accounted for 93%-98% of the seasonal total. Methane fluxes differed among different treatments. Treatment HY with organic manure emitted as high as 258.8 kg hm-2, obviously higher than Treatments NN, FP, YE, and IE without organic manure. However, CH4 emission per unit grain yield did not differ much among treatments, averaging CO2 0.60 kg kg-1, which indicates that cultivation patterns with higher rice production would not substantially enhance CH4 emission. Treatment YE was the lowest in CH4 emission per unit grain yield, being CO2 0.49 kg kg-1, thus deserving wide extension due to increased grain yield, improved N use efficiency and decreased global warming potential simultaneously.