Effects of Combined Biochemical Inhibitors and Fertilization Models on CH₄ and N₂O Emission From Yellow Clayey Field During Rice Growth Season

The addition of urease/nitrification inhibitors is an important measure to reduce greenhouse gas emissions in paddy fields. The interaction effects of biochemical inhibitor combinationsN-(n-butyl)thiophosphoric triamide (NBPT), N-(n-propyl)thiophosphoric triamide (NPPT) and 2-chloro-6-(trichloromethyl)pyridine (CP) and fertilization models (one-off and three-time fertilizations) on greenhouse gases (CH₄ and N₂O) emission flux were investigated from yellow clayey field during rice (Oryza sativa) growth season using two factors randomized block design, and calculated global warming potentials (GWPs) and greenhouse gas intensity (GHGI). The results show that CH₄ and N₂O emission flux had obvious seasonal variation under different fertilization treatments. The three-time urea fertilization treatment significantly reduced CH₄ and N₂O emissions, GWPs and GHGI during rice growth season than those of one-off urea fertilization treatment by 13.5%, 20.7%, 14.4% and 25.0%, respectively. Nitrification inhibitor CP treatment significantly reduced the peak of N₂O emission flux, as well as CH₄ and N₂O emissions during rice growth season under different fertilization models. On the other hand, urease inhibitor NBPT/NPPT combined with CP treatment could more effectively reduce CH₄ and N₂O emissions, as well as GWPs and GHGI during rice growth season. Application of a new urease inhibitor NPPT alone or combined with CP had the similar greenhouse gas emission laws with NBPT during rice growth season. In conclusion, combined biochemical inhibitors and appropriate managements can guarantee the production of rice and effectively reduce greenhouse gas emissions from paddy field, therefore, it is a feasible fertilization practice for low carbon emission and higher yield of rice.