10th U6+ Consortium of African Universities International Conference

This paper examines Alternate Wetting and Drying (AWD), as a water saving strategy and an adaptation measure to impact of climate change in rice growing. This is because of the declining per capita water resources and the buildup of greenhouse gases (GHGs) such as methane gas due to paddy system and anaerobic respiration. The AWD which involves periodic draining and re-flooding of rice fields, has emerged as a promising climate change adaptation strategy because it reduces irrigation water use, improves rice yield, enhances water productivity, and lowers methane emissions. However, its effectiveness varies across environments and management practices, highlighting the need for evidence based systematic synthesis. In this paper, meta-analysis aimed at synthesizing information across scales on the effectiveness of AWD as a a water saving and climate change adaptation strategy in rice production field. The information analyzed include rice grain yield, irrigation water use and its productivity, greenhouse gas emissions, and the economic attributes of production. Comparative analysis between AWD and conventional flood irrigation was done based on information gathered between the years 2000 and 2026. The data considered field experiments, multi-location trials, long-term studies, and on-farm evaluations. The estimated effective sizes using log response ratios and pooling of the results using random-effects models, were used to explore how results varied across climate zones, rice ecosystems, AWD implementation methods, and geographic regions. The results of this review revealed that AWD consistently reduced irrigation water use, increased water productivity and lowered methane emissions corresponding to 27–37%, 32–50%, and 29–47% respectively. Additionally, the review revealed that the magnitude of these benefits varied across climatic zones, rice ecosystems, and management practices. These parameters constitute the next level of investigation in order to realize the absolute benefits of AWD as an alternative to flood irrigated rice production.