Zinc (Zn) oxide nanoparticles (ZnO NPs) have been increasingly utilized in agriculture as an innovative Zn fertilizer, prompting numerous studies to assess their impact on plant growth. However, research on the optimal application methods and dosages of ZnO NPs in rice remains limited. In this study, various basal application dosages (0, 3.75, 7.5, 15, 30 and 60 kg hm⁻²) of ZnO NPs on rice yield, rice quality, and Zn content and distribution in grains were investigated using field experiments in the rice growing seasons of 2022 and 2023. Control experiments were also conducted, including treatments without Zn application and those with ZnSO₄ applied at the same Zn dosage. Results showed that ZnO NP and ZnSO₄ applications led to an increase in rice grain yields in the range of 0.34–0.50 t hm⁻² and 0.06–0.40 t hm⁻², respectively, over the two-year experiment compared to the treatment without Zn application. Furthermore, ZnO NPs improved rice quality by enhancing the head rice rate, reducing chalky grain percentage, and improving taste value and rice breakdown. The application of ZnO NPs significantly elevated Zn content in both milled and brown rice compared with the control. In 2022, Zn content in milled rice increased from 20.79% to 41.67% and in brown rice from 25.20% to 47.31%. In 2023, the increase ranged from 12.18% to 32.18% in milled rice and from 17.68% to 38.66% in brown rice. However, the utilization efficiency of ZnO NPs decreased from 7.02% to 1.26% as the application dosage increased from 3.75 kg hm⁻² to 60 kg hm⁻². Despite this decrease, the utilization efficiency of ZnO NPs remained higher than that of ZnSO₄ at the same Zn dosages. Considering yield, rice quality, Zn fertilizer utilization, and Zn accumulation, a basal application dosage of 7.5–30 kg hm⁻² of ZnO NPs is optimal for improving rice yield, rice quality, and Zn accumulation. This study effectively demonstrated that ZnO NPs could serve as a highly efficient fertilizer for synergistically enhancing rice yield, rice quality, and Zn content in the edible grain fraction.

中文翻译：

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优化 ZnO 纳米颗粒的基础施用剂量以提高水稻产量、水稻品质和锌含量


锌 （Zn） 氧化物纳米颗粒 （ZnO NPs） 在农业中越来越多地用作创新的锌肥料，促使大量研究评估它们对植物生长的影响。然而，关于 ZnO NPs 在水稻中的最佳施用方法和剂量的研究仍然有限。在本研究中，在 2022 年和 2023 年水稻生长季节，使用田间试验研究了 ZnO NPs 的各种基础施用剂量（0、3.75、7.5、15、30 和 60 kg ^hm-2）对水稻产量、水稻品质以及谷物中 Zn 含量和分布的影响。还进行了对照实验，包括不施用 Zn 的处理和以相同 Zn 剂量施用 ZnSO₄ 的处理。结果表明，与未施用锌的处理相比，在为期两年的试验中，施用 ZnO NP 和 ZnSO₄ 导致水稻籽粒产量分别增加了 0.34-0.50 t ^hm-2 和 0.06-0.40 t ^hm-2。此外，ZnO NPs 通过提高整精米率、降低垩白粒百分比、提高味道值和米分谱来改善米质。与对照相比，ZnO NPs 的应用显著提高了精米和糙米中的 Zn 含量。2022 年，精米中的锌含量从 20.79% 增加到 41.67%，糙米中的锌含量从 25.20% 增加到 47.31%。2023 年，精米的增幅从 12.18% 到 32.18% 不等，糙米的增幅从 17.68% 到 38.66% 不等。然而，随着施用量从 3.75 kg ^hm-2 增加到 60 kg ^hm-2，ZnO NPs 的利用效率从 7.02% 下降到 1.26%。 尽管有所降低，但在相同 Zn 用量下，ZnO NPs 的利用效率仍然高于 ZnSO₄。考虑到产量、水稻质量、锌肥利用率和锌积累，7.5-30 kg ^hm-2 的 ZnO NPs 基础施用量对于提高水稻产量、水稻品质和锌积累是最佳选择。这项研究有效地证明了 ZnO NPs 可以作为一种高效肥料，协同提高水稻产量、稻米品质和食用籽粒中 Zn 含量。