Impacts of alternate wetting and drying on rice farmers’ profits and life cycle greenhouse gas emissions in An Giang Province in Vietnam

Abstract

Few studies have simultaneously evaluated the impact of alternate wetting and drying (AWD) on profit and life cycle greenhouse gas (LC-GHG) emissions based on a farm survey for all rice (Oryza sativa L.)-cropping seasons in a year. This study explores whether AWD allows farmers to increase profits and reduce LC-GHG emissions compared with conventional water management. To achieve this objective, survey data were collected by a structured interview from two groups of farmers in An Giang Province in Vietnam: one group was defined as AWD farmers who attended a training course and answered that they conducted AWD, and the other was defined as non-AWD farmers who did not attend the course and answered that they did not conduct AWD. The survey data were analysed by a regression approach and cradle-to-farm gate life cycle assessment. The results showed that the impact of AWD on profit varied depending on the season. The impact of AWD on profit was significant and positive for the early wet season (p < 0.05) and throughout the year (p < 0.1), but the impact was not significant for the dry and late wet seasons. In contrast, LC-GHG emissions by AWD farmers were significantly lower for all seasons when compared to non-AWD farmers. Although few studies have analysed the impacts of AWD on profits in the early wet season, AWD farmers may obtain higher profits than non-AWD farmers due to water from precipitation, which may reduce severe water stress and alleviate some of the adoption constraints. Based on these results, this study recommends implementing AWD throughout the year in An Giang Province if irrigation and drainage systems are available. The results on seasonal variations in impacts and the overall annual impact of AWD on profits and LC-GHG emissions will help farmers make decisions and help to achieve mitigation targets in the nationally determined contribution under the Paris Agreement.