Zinc (Zn) deficiency constitutes a significant global human health challenge. Application of Zn fertilizers to crops, such as oats, offers a rapid solution to the problem. The purpose of this study was to evaluate the feasibility of oat biofortification through Zn fertilization, without causing Zn phytotoxicity to the crop. A field experiment was performed in Valdivia, southern Chile, in which oat (Avena sativa L.) grown in a Duric Hapludand soil was fertilized with zinc sulfate (ZnSO4 · 7H2O) with the following application rates: 0, 14, 43, and 85 kg Zn ha-1, equivalent to 0, 8, 24, and 47 mg Zn kg-1. The application of Zn at treatment rates had no significant effect on grain yield. The application of Zn at the study rates increased DTPA-Zn concentration considerably from 1.3 to 29 mg kg-1 and Zn concentration in oat grain from 22 to 45 mg kg-1. This study suggests that Andisols can be fertilized with Zn at the rate of up to 85 kg ha-1 without a risk of causing Zn phytotoxicity to agricultural crops. This study has practical agronomical implications by demonstrating that DTPA-Zn content of about 20 mg kg-1 is the optimal for increasing grain Zn content in oats grown in Andisols. To the best of our knowledge, this is the first study demonstrating the feasibility to biofortify with Zn crops grown in Andisols and one of few studies on Zn biofortification of Zn in oat.
