Agronomic biofortification of Zinc (Zn) and iron (Fe) in cereal grains is a critical strategy to address human deficiencies in these micronutrients. Our study examined the effects of crop rotation and farming system on Zn and Fe bioavailability in wheat grains, using data from 2011 to 2020 from the Glenlea Long-term Crop Rotation Study, Canada’s longest running study on organic farming. Two crop rotations, continuous annual (spring wheat, flax, oat, soybean) and annual-perennial (spring wheat, flax, alfalfa, alfalfa), managed both organically and conventionally, were fully phased. Compared to conventional farming, organic farming significantly increased grain Zn concentration in six out of ten years, with no significant effect on grain Fe. Additionally, grain Zn was also significantly higher in the annual-perennial rotation compared to the annual rotation in seven of the ten years. A significant interactive effect was observed for grain phytate, which was approximately 35 % lower in the annual-perennial rotation under organic farming than in other treatments. Consequently, the diversified rotation under organic farming significantly reduced the phytate/Zn and phytate/Fe molar ratios, indicating enhanced micronutrient bioavailability for human consumption. However, these effects were strongly associated with reduced phosphorus (P) availability in organic systems, particularly following alfalfa, which limited grain yields. Livestock manure-based compost application improved grain yield and nutrient uptake, but reduced Zn/Fe bioavailability due to increased phytate accumulation. This study demonstrates that diversified crop rotation and organic farming could improve micronutrient bioavailability, but at a cost of lower grain production tied to reduced P availability.

中文翻译：

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通过作物轮作和有机农业提高锌和铁的生物利用度：来自长期研究的见解


谷物中锌 （Zn） 和铁 （Fe） 的农艺生物强化是解决人类缺乏这些微量营养素的关键策略。我们的研究使用 2011 年至 2020 年来自 Glenlea 长期作物轮作研究的数据，检查了作物轮作和耕作系统对小麦谷物中 Zn 和 Fe 生物利用度的影响，Glenlea 长期轮作研究是加拿大运行时间最长的有机农业研究。两种作物轮作，连续一年生作物（春小麦、亚麻、燕麦、大豆）和一年生-多年生作物（春小麦、亚麻、苜蓿、紫花苜蓿），以有机和常规方式进行全面分期进行。与传统农业相比，有机农业在 10 年中有 6 年显著提高了谷物锌浓度，而对谷物铁没有显着影响。此外，与十年中有 7 年的年度轮作相比，谷物 Zn 在年-多年轮作中也显著升高。观察到谷物植酸的交互效应，在有机农业下，谷物植酸在年-多年生轮作中比其他处理低约 35%。因此，有机农业下的多样化轮作显著降低了植酸盐/锌和植酸盐/铁的摩尔比，表明人类食用的微量营养素生物利用度更高。然而，这些影响与有机系统中磷 （P） 可用性的降低密切相关，尤其是在紫花苜蓿之后，这限制了谷物产量。基于畜禽粪便的堆肥施用提高了谷物产量和养分吸收，但由于植酸盐积累增加，Zn/Fe 的生物利用度降低。这项研究表明，多样化的作物轮作和有机农业可以提高微量营养素的生物利用度，但代价是降低粮食产量与降低磷的可用性有关。