Optimizing zinc fertilization technology in wheat for its sustainable production and improved human nutrition

Zinc (Zn) deficiency in soil is a serious constraint affecting the yield and nutritional quality of wheat and, in turn, human health. Zn fertilization for enhancing its density in grains is a prominent technological solution for the problem. Accordingly, the present study (pot experiment) was undertaken to (i) assess the impacts of different Zn fertilization technologies on yield, concentrations of Zn, phytic acid (PA), iron (Fe) and also the bioavailability of Zn in grains and (ii) determine the optimised Zn fertilization technology that balances all the above attributes. To achieve this, six Zn fertilization technologies, namely, soil fertilization alone, combined soil and foliar fertilization at maximum tillering, jointing, flowering, dough stages and also foliar fertilization alone were tested and compared with control (no Zn) in forty different soil series representing two distinct soil orders, Inceptisols and Alfisols. Results showed that relative effectiveness of different Zn fertilization technologies varied for the crop attributes studied. Soil + foliar fertilization was superior in increasing grain yield (10-13% over the control). Moreover, for an optimum balance among all the tested attributes including bioavailability of Zn to human, foliar Zn fertilization at later crop growth stage (i.e. dough) combined with soil fertilization was the best. It was found that biofortified wheat grains obtained through Zn fertilization, on an average, could supply about 1.5 times more bioavailable Zn than the normal grains. Therefore, the outcomes of this study can provide a guideline for sustainable and quality wheat production, which will help address the malnutrition challenge.