Appropriate Micronutrient Fertilization through Soil or Drone-based Foliar Spraying Can Simultaneously Improve Yield and Micronutrient Nutritional Quality of Maize Grains

• DOI: 10.20944/preprints202504.0694.v1
• Publication Date: 2025-04-10T00:46:11Z
• Authors: Qiang Zhao; Feifei Wan; Xinrui Zhang; Zhaoqian Jia; Lei Ma; Yinghua Zhu; Haiyong Xia

To fully reveal impacts of agronomic managements on yield-nutrition relationships in maize kernels for micronutrient biofortification while enhancing yields simultaneously, effects of various soil fertilization and drone-based foliar spraying measures were studied. Maize yields and grain Zn concentrations were simultaneously increased by 12.4%-23.0% and 41.4%-110.1%, respectively, in the soil experiment. Soil improvements by the extra-addition of humic acid (HA), bio-organic (BO) and/or Ca-Mg-S-Si fertilizers into the calcareous soil tested increased maize grain Zn concentrations more than Zn alone, with an average increase of 4.7 mg/kg. The combination of soil amendments (HA, HA+BO, HA+BO+Ca-Mg-S-Si) and Zn not only improved maize grain Zn concentrations but also enhanced concentrations of other micro- and macronutrients, mainly including Fe, Mn, Cu, Ca and Na, and even P, K, Mg and B, achieving a co-biofortification of multi-nutritional elements, i.e., “killing many birds with one stone”. Maize grain yields were positively correlated with concentrations of Zn, Fe, Mn, Ca and Mg in the soil experiment. Foliar spraying of Zn, Fe and Se alone or a mixture of them increased maize yields and grain micronutrient concentrations simultaneously. Notably, the drone-based foliar spraying of a mixture of Zn, Fe and Se simultaneously enhanced maize grain yields from 11.5 to 13.9 t/ha by 20.9%, and concentrations of Zn from 18.2 to 28.9 mg/kg by 58.8%, of Fe from 20.4 to 27.5 mg/kg by 34.8% and of Se from 93.7 to 468.1 ug/kg (> the target biofortification value of 150 µg/kg), achieving a co-biofortification of multiple micronutrients. Therefore, a dual-benefit in maize grain yields and micronutrient nutrition could be effectively achieved by appropriate soil micronutrient fertilization and the drone-based foliar micronutrient spraying. These results provide a better understanding on the yield-nutrition relationship of maize and feasible manipulations to achieve a double-win in yield and nutrition rather than the dilution effect.