Using sowing date management to promote micronutrient quality and alleviate cadmium accumulation in rice grains

Rice micronutrients and toxic metal levels are important quality issues impacting “hidden hunger” and food safety. The aim of this study was to evaluate the effects of sowing date (SD) on element accumulations in rice grains. We conducted a rice SD experiment every 7 days from May 10 to June 21 in 2017 and 2018 using 2 japonica ( Oryza sativa L.) cultivars. The rice yields were determined, and 19 element contents in the grains were measured via inductively coupled plasma mass spectrometry. Analysis of variance indicated that early SD significantly promoted the rice yields and the micronutrient (i.e., Cu, Fe, Mn, Ni, and Zn) levels in grains. However, early SD also significantly increased Cr and Pb contents but significantly limited Cd accumulations in rice grains. Anyway, the element contents of all determined samples satisfied the requirements of maximum permissible concentrations (GB2762–2012) in this uncontaminated area. Redundancy analysis indicated that temperature and precipitation were the main meteorological drivers of element accumulations. Meanwhile, Cd accumulation was simultaneously affected by the antagonism of Fe/Zn. Thus, we concluded that SD management could be a feasible strategy for promoting micronutrient quality of rice grains and further alleviating Cd accumulations when aiming at high yields.