Reviewing Manganese and Zinc Foliar Fertilization Approaches and Results through a Quantitative Metadata Analysis

Abstract

Manganese (Mn) and zinc (Zn) are essential elements for plants. However, deficiencies of these elements are common, reducing crop yields globally. In this context, foliar application of Mn and Zn fertilizers has gained attention due to its precision and efficiency compared to conventional soil fertilization methods. Herein, we aimed to establish an overview of the foliar fertilization with Zn and Mn through a quantitative metadata analysis from 162 peer-reviewed papers published between 2012 and 2023. The study revealed that the most widely employed sources of Zn and Mn were sulfate salts and commercial formulations, respectively. The experimental conditions varied greatly among the studies; most of them were conducted under field conditions. Relative air humidity, an important factor influencing foliar nutrient absorption, was inconsistently reported across the studies. Notably, although crop yield evaluations were scarce, the majority of studies reported positive effects of Mn and Zn foliar applications on plant parameters, underscoring the potential for enhancing agricultural productivity. Further research is warranted to elucidate optimal application strategies and address the limitations in current methodologies.