Impacts of variable soil drying in alternate wetting and drying rice systems on yields, grain arsenic concentration and soil moisture dynamics
Continuously flooded rice systems are a major contributor to global rice production and food security. Allowing the soil to dry periodically during the growing season (such as with alternate wetting and drying irrigation - AWD) has been shown to decrease methane emissions, water usage, and heavy metal accumulation in rice grain. However, the effects of AWD on rice yields are variable and not well understood. A two-year study was established to quantify the impacts of a range of treatments differing in AWD severity (degree of soil drying between flooding events) on yield (as well as factors that may affect yields), soil hydrology in the soil profile, and grain arsenic (As) concentrations relative to a continuously flooded control (CF).