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.

中文翻译：

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利用播期管理提高微量营养素质量并缓解稻谷镉积累

大米微量营养素和有毒金属含量是影响“隐性饥饿”和食品安全的重要质量问题。本研究的目的是评估播种日期（SD）对水稻籽粒中元素积累的影响。我们在 2017 年和 2018 年的 5 月 10 日至 6 月 21 日期间每 7 天使用 2 个粳稻 (Oryza sativa L.) 品种进行了一次水稻 SD 试验。测定水稻产量，采用电感耦合等离子体质谱法测定稻谷中19种元素的含量。方差分析表明，早期SD显着提高了水稻产量和籽粒中微量营养素（即Cu、Fe、Mn、Ni和Zn）水平。然而，早期SD也显着增加了水稻籽粒中Cr和Pb的含量，但显着限制了Cd的积累。反正，所有测定样品的元素含量均满足该未污染区最高允许浓度（GB2762-2012）的要求。冗余分析表明，温度和降水是元素积累的主要气象驱动因素。同时，Cd 的积累同时受到 Fe/Zn 拮抗作用的影响。因此，我们得出结论，在以高产为目标时，SD 管理可能是提高水稻微量营养素质量和进一步减轻 Cd 积累的可行策略。