Greenhouse gas emission patterns and global warming potential as a result of establishment techniques and nutrient managements in rainfed rice

Rice paddies are a significant source of greenhouse gases (GHG), especially methane (CH₄)_.As 52% of rice growing area in India is rainfed, it is necessary to quantify GHG emissions to study their effect on climate change. This knowledge can help develop climate change mitigation and adaptation strategies. By studying GHG emissions from rainfed rice, we can develop productive sustainable farming practices which minimize adverse environmental impacts. With this objective, a field experiment was conducted in 2021 and 2022 at experimental field of College of Agriculture, CAU to study impact of establishment techniques and nutrient managements on emission patterns of CH₄, CO₂ and N₂O. Global warming potential (GWP), greenhouse gas intensity (GHGI), carbon equivalent emissions (CEE) and grain yield were also estimated. Treatments comprised of direct seeded (broadcasting) (E₁), direct seeded (line sowing) (E₂), Transplanting (random) (E₃), Transplanting (line) (E₄) in establishment techniques and Chemical@60:40:30 kg NPK ha⁻¹ (N₁), Organic@10t ha⁻¹ FYM (N₂) and Integrated nutrient management @30:20:15 kg NPK ha⁻¹ + 5t ha⁻¹ FYM (N₃) in nutrient management. Evaluating pooled data from both years revealed that significantly lower CH₄ and CO₂ flux was recorded in E₂ and E₃, respectively. N₂O emission was lowest in E₄. Also, N₁ recorded significantly lower CH₄ and CO₂ emissions and N₂ the lowest N₂O emission. E₂ and N₁ produced significantly lower GWP, CEE and GHGI. Grain yield was significantly higher in E₄ and N_3. This implies that direct seeded method and integrated nutrient management with application of 30:20:15 kg NPK ha⁻¹ with 5t ha⁻¹ FYM may be employed to successfully mitigate the GWP of GHGs emitted from rained rice systems without compromising yield.