Zinc biofortification strategies in food-type soybean cultivars

Abstract

Reducing the risk of Zn-deficiency in humans by diversifying human diet and through agricultural interventions, such as agronomic biofortification, is still a major challenge. This greenhouse study used a number of biofortification strategies to investigate the effect of Zn fertilization on soybean grain cultivars intended for human consumption. A completely randomized 5×3 factorial design with four replications was used. The design included five different Zn application strategies as the main plot. These were (1) soil application; (2) foliar application at the vegetative growth stage 4 (V4) growth stage; (3) foliar application at vegetative growth stage 8 (V8); (4) foliar application at reproductive growth stage 4 (R4); and (5) a control (without Zn). Three soybean cultivars (BRS 213, BRSMG 790A, and BRS Favorita RR® ) were assigned as sub-plots. Zinc foliar fertilization at stage R4 was found to be the most efficient method for soybean cultivation when Zn availability in the soil was low. The cultivars had different Zn accumulation responses, and the cultivar BRSMG showed the highest Zn increase. Zinc fertilization increased the protein content in soybean grain, plant height, and the number of grains per plant.