Agronomic Biofortification of Food Crops with Micronutrients.

Agronomic biofortification of food crops, where fertilizers are used to increase micronutrients in edible crop parts, can be an effective component of a food system approach to reduce micronutrient malnutrition in human populations.  Selenium (as selenate) is the most suitable micronutrient for this strategy, as demonstrated by the whole-country biofortification program conducted in Finland since 1984.  Within two years of the program’s commencement, population selenium status had approximately doubled. Zinc, especially with two strategic foliar applications of zinc sulphate, including one together with urea, can also be an effective agronomic biofortification candidate.  Iodine, when applied to the soil as either iodide or iodate, can be effective in biofortifying leafy vegetables.  Selenium and zinc added to standard fertilizers for maize and other food crops have the potential to improve population health (selenium) and crop yields (zinc) in countries like Malawi, where both micronutrients are deficient in most soils.  Challenges include improving application efficiency and residual effect and, in the absence of mandated centralized addition to fertilizers, provision of farmer incentives.