Alternate Wetting and Drying (AWD) Increase Rice Yield, and Water-Use Efficiency while Mitigating Methane Emissions from Synchronized Rice Systems

Abstract

A field experiment was conducted at a synchronized cropping area on a farmer's field in Nokla, Sherpur, Bangladesh using Boro rice (SL8H Super Hybrid), to identify effective water management practices for water saving, methane emission reduction, and sustainable yield. The experiment followed a Randomized Complete Block Design with two treatments and four replications. The treatments were as follows: T₁ = Irrigation with alternate wetting and drying (AWD), and T₂ = Non-AWD, which involved normal irrigation (farmer's practice) with continuous standing water in the field. The results showed that the AWD plot had a higher grain yield (6.61 t ha⁻¹) compared to the Non-AWD plot (5.83 t ha⁻¹), with a 13.4% increase in yield and a 16% reduction in irrigation water use. Moreover, cumulative methane (CH₄) emissions were higher under the Non-AWD treatment compared to the AWD treatment throughout the season. The AWD irrigation system reduced CH₄ emissions by 35%, likely due to intermittent aeration that makes the soil oxic, promoting the oxidation of CH₄ by methanotrophic microbes. This leads to a decrease in methane emissions. Thus, the implementation of alternate wetting and drying (AWD) in Boro rice cultivation proves to be an effective management strategy for reducing CH₄ production and emissions, contributing to more sustainable rice production.