Agronomic biofortification of crops to fight hidden hunger in sub-Saharan Africa

Micronutrient deficiencies or ‘hidden hunger’ resulting from unbalanced diets based on starchy staple crops are prevalent among the population of sub-Saharan Africa. This review discusses the effectiveness of agronomic biofortification - the application of mineral micronutrient fertilizers to soils or plant leaves to increase micronutrient contents in edible parts of crops – and it's potential to fight hidden hunger. There is evidence that agronomic biofortification can increase yields and the nutritional quality of staple crops, but there is a lack of direct evidence that this leads to improved human health. Micronutrient fertilization is most effective in combination with NPK, organic fertilizers and improved crop varieties, highlighting the importance of integrated soil fertility management. Agronomic biofortification provides an immediate and effective route to enhancing micronutrient concentrations in edible crop products, although genetic biofortification may be more cost effective in the long run. •Micronutrient deficiencies are prevalent in crops and people in sub-Saharan Africa.•Agronomic biofortification can increase yields and micronutrient contents of crops.•There is a lack of direct evidence on the effectiveness to improve human health.•Sustainable agronomic biofortification requires integrated soil fertility management.•Implementation in sub-Saharan Africa is hampered by lack of knowledge and access to inputs.