Enhancing Rice Yield and Mitigating Greenhouse Gas Emissions Through the Integration of Alternate Wetting and Drying With γ‐Polyglutamic Acid

Background and Aim To address the dual challenges of water scarcity and climate change in rice production, a 2‐year field study was conducted to assess the combined effects of water management practices and γ‐polyglutamic acid (γ‐PGA) application on greenhouse gas (GHG) emissions, water productivity, and economic benefits. Methods Three water regimes—conventional flooding (C), alternate wetting and drying (A), and drought management (D)—were tested with and without the addition of 25 kg of γ‐PGA per hectare. Results Compared to the conventional flooding (C) regime, the water‐saving regimes (A and D) significantly reduced methane (CH 4 ) emissions while increasing nitrous oxide (N 2 O) emissions. γ‐PGA application reduced CH 4 and N 2 O emissions across all water treatments, improving soil aggregation and redox potential. The AAP treatment (alternate wetting and drying irrigation combined with γ‐PGA application) achieved the highest rice yield and crop water productivity, along with the lowest GHG intensity and carbon footprint. Consequently, the net economic benefit to the ecosystem was maximized under the AAP treatment, demonstrating a synergistic effect integrating water conservation, yield enhancement, emission reduction, and economic return. Conclusion These findings suggest that integrating A irrigation with γ‐PGA amendment is a sustainable approach to balancing productivity and environmental sustainability in rice cultivation. Further research should focus on elucidating the underlying microbial mechanisms and assessing the long‐term adaptability of this approach in different agroecological regions.