中文摘要：

2007～2008年采用3种追肥时间（雨前追肥、雨时追肥和雨后追肥）进行田间试验,观测小麦拔节-成熟期N2O排放,以探讨追肥时间对麦季N2O排放的影响。结果表明,与雨前追肥和雨时追肥相比,雨后追肥小麦拔节-成熟期N2O排放量分别减少37%～67%和22%～46%。各处理小麦产量无显著差异（p〉0.05）。土壤水分含量是影响小麦拔节-成熟期N2O排放的关键因素。雨后趁墒追肥能显著减少小麦拔节-成熟期N2O排放且不影响小麦产量,是较为合理的追肥方式。

英文摘要：

To study effect of timing of topdressing on N2O emission from wheat fields during the period from the jointing stage till the maturing stage of wheat,a field experiment was conducted to have three topdressing schedules（topdressing before rain,topdressing during rain and topdressing after rain） in jointing-maturing stage of wheat from 2007 to 2008.Results show that N2O emission was 37%~67% and 22%~46% less in fields topdressed after rain,than in fields topdressed before rain and during rain,respectively.No significant difference was observed between the treatments in wheat grain yield（p0.05）.Soil water content was the key factor affecting N2O emission during that wheat growing season.Topdressing after rain when soil was wet is an appropriate topdressing method,which may decrease N2O emission significantly in the wheat-growing season with no adverse effect on wheat yield.