A Meta-Analysis of the Impact of Foliar Feeding of Micronutrients on Productivity and Revenue Generation of Forage Crops

ABSTRACT: Food security assurance to meet the demands of increased population growth requires a proportional increase in milk and meat production which, in turn, depends on animal nutrition. Assessing foliar application of micronutrients for production of substantive quantities of good quality forage must be a goal of modern, profit-oriented, sustainable agriculture and plants with better competitive ability as compared to weeds. This meta-analysis made a quantitative and qualitative analysis of the impact of foliar feeding of micronutrients (iron, zinc, copper, sulfur and boron) on forage crops under varying pedo-climatic conditions. Weighted and unweighted meta-analyses were performed on 139 studies to evaluate 19 independent variables (9 qualitative, 5 qualitative, 5 economic) in comparison to no spray of micronutrients. Foliar feeding through application of one, two or more micronutrients with single or multiple sprays positively influenced agronomic and physiological traits, which led to significantly higher green forage (7-19%) and dry matter biomass. Nutritional quality, particularly crude protein (1.9-11.0%) and digestibility (8-17%), was improved by foliar spraying of micronutrients. Economic outputs were also increased as additional benefits rendered by foliar applied micronutrients surpassed their expenditures. For this data set, it is concluded that foliar feeding of micronutrients has the potential to boost forage yield, nutritional quality and revenue of cereals, legumes and non-conventional forage crops (quinoa and medick) depending on soil fertility status, concentration of applied micronutrients, number of foliar sprays, crop growth stage for foliar feeding and specific agro-environmental conditions.