Zinc and iron application in conjunction with nitrogen for agronomic biofortification of field crops – a review

Abstract

Context Maintaining food and nutritional security for the ever increasing population of the world is a great chllenge. Zinc and iron are important micronutrients for both human health and plant growth. Insufficient intake of these micronutrients leads to their deficiency in human body which causes morbidity and mortality in different age groups of poor populations in developing countries. Aims Therefore, agronomic biofortification is considered the most promising approach to alleviate zinc and iron malnutrition in developing countries. Methods The studies reviewed in this article clearly show that the combined application of zinc and nitrogen, iron and nitrogen, and zinc, iron and nitrogen to the soil or to the foliage during the reproductive phase leads to enhanced nutrient (zinc and iron) content in edible parts of crop plants. This happens as the remobilisation and translocation of zinc, iron and urea are governed by the same genetic pathways inside the plant. Key results The soil/foliar application of micronutrients (zinc and iron) along with nitrogen (mainly through urea) improves not only the micronutrient (zinc and iron) content in edible parts of the crop plants but also the crop productivity, and thus, is a win–win situation for growers as well as consumers. Conclusions Foliar application of urea at 1–2% along with zinc or iron or both during the reproductive phase has been found more effective for biofortification point of view. Implications This article reviews the effects of zinc and iron application in combination with nitrogen on agronomic biofortification in important field crops.