GENOTYPIC VARIATION IN TERMS OF BIOMASS YIELD AND MICRONUTRIENTS’ ACCUMULATION IN RESPONSE TO ZINC AND IRON APPLICATION IN ALFALFA

With enhanced sustainability in food and feed production systems, agronomic biofortification is a key strategy to alleviate micronutrient deficiencies in animal diets, with indirect benefits for human nutrition through improved quality of animal-derived foods. A field experiment, carried out using a randomized complete block design with a split-plot arrangement, included two levels each of zinc (Zn, 0 and 2 kg ha⁻¹) and iron (Fe, 0 and 2 kg ha⁻¹) and their integrated application (2 kg Zn ha⁻¹ + 2 kg Fe ha⁻¹) in alfalfa (Medicago sativa L.). The Zn and Fe foliar application enhanced the concentration of both micronutrients in alfalfa without compromising its yield and quality. Alfalfa cultivars responded differently to biofortification treatments, and the cultivar California 55 showed the highest recovery efficiency (RE) of Zn (119.4%) and Fe (68.0%) at the fifth harvest. An RE value above 100% indicates the applied nutrient both contributed directly to uptake and enhanced the mobilization or utilization of native soil reserves, leading to greater total accumulation than the amount applied. The results highlighted that foliar biofortification is an effective and sustainable approach to improve the nutritional quality of forage crops, thereby contributing to livestock health, food security, and agricultural resilience.