Nano-enabled agriculture is a vibrant research area; nonetheless, reports on effective nanofertilizers are rather scant. Hence, we evolved novel, easy, and scalable synthetic routes for environmentally benign Fe-oxalate capped metal oxide (Fe–Mn and Fe–Cu) nanomaterials (OCIMn_ox and OCICu_ox) for agricultural use (Patent no. 343590). The materials were systematically characterized through PXRD, FT-IR, HR-SEM, HR-TEM, and XPS analyses, which induced the least toxicity to plants, soil microbes, and earthworms. These materials corrected soil acidity by maintaining the soil pH above 6. Their application increased the surface area by ∼1.5–1.7 fold, water holding capacity by ∼1.4–1.5 fold, and organic C by ∼1.3–1.4 fold in soil as compared to non-nanoscale fertilizers (sulphates and EDTAs of Fe/Mn/Cu). The 10 ppm dose of OCICu_ox and OCIMn_ox remarkably enhanced the availability of N (383–385 ppm) and P (75–79 ppm) in soil compared with their non-nanoscale counterparts. Their application in nutrient-fatigued soil could efficiently alleviate Fe, Mn, and Cu deficiency, enhance soil bacterial growth by ∼4–9 fold, and augment siderophore-producing bacteria. Furthermore, oxidative stress factors were minimized in earthworms and plants cultivated in nano-exposed soil. Focused experimentations showed that OCICu_ox and OCIMn_ox stabilized soil pH, probably by adjusting the H⁺ abundance, and optimized nutrient availability by increasing the net-negative charge in soil. Eventually, plant productivity was stimulated through greater N uptake (>6%), 3–10 fold greater up-regulation of expression of vital genes [glutamine synthetase-2 (GS2), glutamate synthase (GOGAT), and nitrate reductase (NR)], and a higher rate of photosynthesis than FeSO₄. In conclusion, the innovatively synthesized OCIMn_ox and OCICu_ox showed great promise as micronutrient nanofertilizers for future applications.

中文翻译：

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纳米土壤改良剂消除微量营养素缺乏症：土壤理化特性和植物分子反应

纳米农业是一个充满活力的研究领域。尽管如此，关于有效纳米肥料的报道却相当少。因此，我们为环境友好的草酸铁封端金属氧化物（Fe-Mn 和 Fe-Cu）纳米材料（OCIMn _ox和 OCICu _ox）开发了新颖、简单且可扩展的合成路线。) 农业用途（专利号 343590）。通过 PXRD、FT-IR、HR-SEM、HR-TEM 和 XPS 分析系统地表征了这些材料，它们对植物、土壤微生物和蚯蚓的毒性最小。这些材料通过将土壤 pH 值保持在 6 以上来纠正土壤酸度。与它们相比，它们的施用使土壤中的表面积增加了约 1.5-1.7 倍，持水能力增加了约 1.4-1.5 倍，有机碳增加了约 1.3-1.4 倍。非纳米级肥料（Fe/Mn/Cu 的硫酸盐和 EDTA）。OCICu _ox和 OCIMn _ox的 10 ppm 剂量与非纳米级对应物相比，显着提高了土壤中 N (383-385 ppm) 和 P (75-79 ppm) 的可用性。它们在养分疲劳土壤中的应用可以有效缓解 Fe、Mn 和 Cu 的缺乏，使土壤细菌生长增加约 4-9 倍，并增加产生铁载体的细菌。此外，在纳米暴露土壤中培养的蚯蚓和植物中的氧化应激因素被最小化。重点实验表明 OCICu _ox和 OCIMn _ox稳定了土壤 pH 值，可能是通过调节 H ⁺丰度，并通过增加土壤中的净负电荷来优化养分利用率。最终，通过更高的氮吸收 (>6%)、3-10 倍的重要基因 [谷氨酰胺合成酶-2 ( GS2 )、谷氨酸合成酶 ( GOGAT)和硝酸还原酶 ( NR )表达的更大上调刺激植物生产力]，以及比 FeSO ₄更高的光合作用速率。总之，创新合成的 OCIMn _ox和 OCICu _ox作为微量营养素纳米肥料在未来的应用中显示出巨大的潜力。