施氮方式与添加脲酶/硝化抑制剂对稻季NH3挥发和N2O排放的影响

【目的】分析施肥方式及添加脲酶/硝化抑制剂对稻田NH₃挥发和N₂O排放的影响，基于稻田NH₃和N₂O减排的效果评价优化施肥措施的可行性。【方法】在太湖地区开展为期两年的稻季田间小区试验，供试脲酶抑制剂为N-丁基硫代磷酰三胺(NBPT)，硝化抑制剂为对羟基苯丙酸甲酯(MHPP)，用量为施氮量的1%。设置6个处理：1)不施氮肥对照(CK);2)表施尿素N 300 kg/hm² (当地常规施肥，CN);3)表施尿素N 225 kg/hm²(RNB);4)尿素N 225 kg/hm²,50%表施，50%深施(RND);5)表施尿素N 225 kg/hm²+NBPT+MHPP(RNB+DI);6)尿素N 225 kg/hm²+NBPT+MHPP,50%表施，50%深施(RND+DI)。每次施肥后两周内，用密闭式抽气法监测稻田NH₃挥发，在水稻生育期内用静态箱—气相色谱法监测稻田N...

Effects of nitrogen application methods combined with urease/nitrification inhibitor on decreasing NH3 volatilization and N2O emission in rice season

  【Objectives】  NH₃ volatilization and N₂O emission from paddy fields were determined under different fertilization methods and urease/nitrification inhibitor addition, to optimize fertilization measures.   【Methods】  A two-year paddy field experiment was conducted in the Taihu Lake region. The urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT) and nitrification inhibitor methyl 3-(4-hydroxyphenyl) propionate (MHPP) were applied at 1% urea-N. The six treatments include no N application (CK), broadcasted urea N at 300 kg/hm2 (conventional fertilization, CN), broadcasted urea N at 225 kg/hm2 (RNB), 50% in deep urea N application at 225 kg/hm2 (RND), broadcasted urea N application at 225 kg/hm2+NBPT+MHPP (RNB+DI), and 50% in deep urea N placement at 225 kg/hm2+NBPT+MHPP (RND+DI). The dynamic chamber technique was used to monitor NH₃ volatilization flux from the paddy field within two weeks after fertilization. The static chamber-gas chromatography method was used to monitor N₂O emission flux from paddy field across the rice season.   【Results】  1) The NH₃ volatilization lasted for 7 days after fertilization. The total NH₃ volatilization after broadcasting basal and tillering fertilizer accounted for 86.63%–91.76% of the total NH₃ volatilization. The N₂O emission flux peaks appeared after fertilization and halfway through aeration. 2) Compared with the CN, RNB decreased total NH₃ volatilization and N₂O emission by 29.69%–39.41% and 13.43%–23.37%, respectively. 3) Compared with the broadcasted urea application (RNB), deep placement of urea (RND) decreased total NH₃ volatilization and N₂O emission by 53.50%–72.05% and 16.66%–23.43%, respectively (P<0.05). 4) Compared with RNB, RNB+DI decreased total NH₃ volatilization and N₂O emission by 9.57%–22.27% and 8.77%–15.67%. 5) Compared with CN, RND+DI (P<0.05) decreased total NH₃ volatilization and N₂O emission by 76.89%–82.29% and 37.98%–48.71%.   【Conclusions】  NH₃ volatilization and N₂O emission can be decreased by reducing the N application rate, N-fertilizer deep placement and adding inhibitors in urea, which had a better effect on NH₃ volatilization reduction. The combination of these optimized N fertilization measures can achieve optimum NH₃ and N₂O emissions reduction effects. The comprehensive integration measure is feasible in practice and provides technical support for promoting rice production.