Effects of three different alternate wetting and drying regimes in rice cultivation on yield, water use, and water use efficiency in a clay soil during a wet year.
Water available for irrigation is declining in many rice-growing regions around the world. Global populations continue to rise, increasing crop production demand. Rice production systems must face the dilemma of maintaining or increasing yields with less water available to irrigate. Alternate wetting and drying (AWD) has shown to be an effective tool for water conservation in irrigated rice systems. Research on AWD practices is lacking and more information is needed to verify the success of AWD across varying soil types. More work is needed to develop clear recommendations for AWD irrigation practices in Arkansas. In this study we compared the effects of three different AWD regimes and a continuous flood management on rice yields and water-use efficiency (WUE) from a conventional, pure-line cultivar (Roy J) and a hybrid (XL753). The study was located in the northeast corner of the Mississippi delta rice-growing region in Arkansas and results were complicated by a high rainfall pattern in 2015, and unknown factors contributing to low yields even in the conventionally flooded treatments. Even with these complications, the trends in the data indicated that AWD is a feasible water management practice for rice in Arkansas. For both cultivars, all AWD regimes tested in this experiment were associated with a loss in yield, the hybrid cultivar had a higher yield than the conventional cultivar in all treatments. Water-use efficiency for the wettest AWD treatment was higher than the conventional flood treatments and the dryer AWD treatments. Difference in WUE between cultivars was significant and suggests that the hybrid may have a higher WUE than the conventional.