Comparative study of different water management practices on element content in rice grain, yield, and yield components

Abstract

Rice (Oryza sativa L.) is a critical crop for global food security; however, under certain conditions, rice grains can accumulate elevated levels of arsenic (As) and cadmium (Cd). Research has shown that alternate wetting and drying (AWD) of rice fields, rather than maintaining a continuous flood (FLD), can lower concentrations of both total As (tAs) and the more toxic inorganic As (iAs) in milled rice. Unfortunately, irrigation management that oxidizes the soil can potentially result in higher Cd concentrations. This 2-year study tested the hypothesis that AWD with two short drains is better than a single mid-summer drain (MSD) or flood (FLD) on rice yield, element content, and various starch quality attributes. The results revealed that AWD did not reduce yield compared to MSD and FLD and that AWD and MSD resulted in a negligible milling quality penalty compared with FLD. AWD had the added benefit of significantly reducing tAs and iAs in grains compared with FLD and MSD. AWD did not increase grain Cd in brown rice when compared with FLD and caused either no consequential change or a desirable increase in 10 other elements. Protein concentration was reduced by only half a percentage point, and starch quality attributes were minimally impacted as well. This study highlights the importance of water management practices in minimizing accumulation of hazardous elements such as As and Cd in rice grains while enabling sustainable rice production with conventional yields and cooking quality attributes.