氮肥管理措施对黑土玉米田温室气体排放的影响

采用静态箱-气相色谱法研究了不同氮肥管理措施(农民常规施肥、减氮20%、添加硝化抑制剂、施用控释肥)对黑土玉米田温室气体排放的影响.结果表明:黑土玉米田施肥(基肥和追肥)后1~3d出现N2O排放峰,施肥后16d内N2O排放量占生育期总排放量的28.8%~41.9%.减施氮肥20%显著降低土壤N2O排放,生育期内的N2O累积排放量减少了17.6%~46.1%,综合温室效应降低30.7%~67.8%,温室气体排放强度降低29.1%~67.0%.等氮量投入时,添加吡啶抑制剂土壤N2O排放量、综合温室效应和温室气体排放强度最低.玉米拔节~乳熟期出现了较强的土壤CO2排放,黑土玉米田是大气中CH4的一个较弱的“汇”,施氮和添加硝化抑制剂对黑土玉米田CO2排放和CH4吸收没有显著影响.添加硝化抑制剂和施用控释肥不影响玉米产量.在本试验条件下,减氮20%并添加吡啶抑制剂在保证玉米产量的同时, 减排增收效果优于其他施肥措施,适宜在黑土区玉米种植中推广使用.

Effects of nitrogen fertilizer management on greenhouse gas emissions from maize field in black soil

Greenhouse gas (GHG) emission from agricultural production is an important source of atmospheric GHG. It is crucial to explore corresponding measures and their effect on mitigating GHG emissions. To gain high crop yield without increasing GHG emissions, it is necessary to propose new nitrogen (N) fertilizer management strategies. This study was conducted to determine the effects of different nitrogen fertilizer management (conventional fertilization, decreasing within 20% of the conventional N application rate, nitrification inhibitor and controlled release fertilizer) on greenhouse gases emissions from spring maize field in black soil using the static chamber-gas chromatograph method. The results showed that: the peak of N2O emission flux occurred within 1~3days after basal fertilization and top-dressing from maize field in black soil. 28.8%~41.9% of total N2O emissions during maize growth period were emitted within the first 16days after basal fertilization and top-dressing. Decreasing within 20% of the conventional N application rate significantly decreased the total N2O emissions. Compared with the conventional fertilization with higher rates of N fertilizer (185kg N/ha), the total N2O emissions and annual global warming potential (GWP) were decreased by 17.6%~46.1% and 30.7%~67.8% respectively under improved N management practices, whereas greenhouse gas intensity (GHGI) were decreased by 29.1%~67.0%. Nitrification inhibitor addition showed the lowest total N2O emissions, GWP and GHGI compared with other treatments. Higher CO2emission fluxes occurred from elongating to milky-riping stage. The maize field was a weak sink of atmospheric CH4 in black soil. The emission fluxes of CO2 and CH4 were not affected by N application rate (148~185kg N/hm2) and nitrification inhibitor, respectively. Nitrification inhibitor and controlled release fertilizer had no significant influence on the yield of maize. Under the conditions of our experiment, decreasing N rate by 20% at the basic level of 185kg N/hm2 combined with nitrification inhibitor can maintain the stable yield of maize, therefore could be served as an appropriate practice for mitigating GHG emissions with reduction of cost in black soil area.