Agronomy biofortification of wheat grain in a saline and calcareous soil

Agronomy biofortification is an important crop management strategy to enhance concentrations of micronutrients in edible portions. The availability of micronutrients for plant uptake is reduced by the high salinity, pH, and lime of soils. Hence, this study aimed to determine the most appropriate time and the best ratio of zinc (Zn) and iron (Fe) consumption during the wheat growth stages in a saline and calcareous soil. The experiment consisted of two factors with four levels; 0, 30, 60, and 120 kg Zn ha(-1) as Zn0, Zn1, Zn2, and Zn3 respectively, and 0, 2.5, 5, and 7.5 kg Fe ha(-1) as Fe0, Fe1, Fe2, and Fe3 respectively, in a randomized complete block design with four replications. The results showed that the interaction effects of Fe and Zn fertilizers application were significant on the wheat yield indices and concentration of Fe and Zn in wheat shoots and grain. The simultaneous application of 120 kg Zn ha(-1) and 5 kg Fe ha(-1) caused significant improvement (p < 0.05) in thousand kernel weight (9.1%) and subsequently grain yield (23.4%) compared to the control treatment. The Zn concentration in the wheat shoot during tillering (37.0-58.2 mg Zn kg(-1)) was higher than the other two growth stages (elongation (29.2-40.8 mg Zn kg(-1)) and booting (20.0-31.0 mg Zn kg(-1))). While the highest Fe concentration in wheat shoots was observed at the stem elongation stage (98.5-268.8 mg Fe kg(-1)), then the booting stage (91.0-150.8 mg Fe kg(-1)) and finally the least absorption was at the tillering (80.0-120.0 mg Fe kg(-1)). Because of the high calcium carbonate, salinity and Zn- deficient soil of the experimental site, the Zn concentration in wheat grain was obtained in a range of 3 to 19 mg kg(-1). The results clarified that the fertilizer application of 30 kg Zn ha(-1) and 2.5 kg Fe ha(-1) can be proportionally and simultaneously increased the concentration of Fe and Zn in wheat grain by 100%. Therefore, the soil application of 30 kg Zn and 2.5 kg Fe per hectare proposed for improvement in quantitative (619 kg ha(-1) increase in wheat grain yield) and qualities (100% increase in grain Zn and Fe concentration and 8% increase in thousand kernel weight) indices of wheat yield in calcareous and saline soils.