Paddy ecosystems constitute a major source of greenhouse gases (GHG), dominated by methane (CH4) and nitrous oxide (N2O), across the South Asian region. Typical water-logged conditions favour simultaneous production of CH4 and N2O in paddy fields, while their transport and subsequent emission across the soil-plant-atmosphere continuum are primarily diffusion-controlled. A wide range of atmospheric (e.g., temperature) and subsurface (e.g., soil type, soil organic carbon, soil redox status) variables play a vital role in the production and diffusive transport of the gases, although the exact controlling mechanisms are not well understood. This study hypothesis the presence of “critical windows of water and gas diffusivity” in paddy soils, as also observed in other ecosystems (e.g., grazed pasture), which enables excessive emission of CH4 and N2O from rice fields. Since the critical windows are regulated by soil and atmospheric controls and country-
specific water management practices in the region, collaborative research efforts are essential to understand the controlling factors and develop mechanisms to constrain the windows. The proposed project forms a regional research initiative to distinguish the critical water and gas diffusivity windows for paddy soils and understand the impact of soil and environmental factors and water management strategies. The study will propose the best management practices the region can adopt to avoid the critical windows and minimize GHG emissions.