Effect of Soil Organic Treatments on Zinc Biofortification of Wheat Grain Cv. Rakhshan

Agronomic biofortification is one of the approaches to alleviate zinc deficiency in wheat. In this approach by changing the status of zinc, it could be available to plant. The application of organic fertilizers can stimulate physicochemical properties of soil and nutrition cycling which enhances zinc bioavailability. This study was conducted to evaluate the application of some organic compounds on grain zinc concentration and phytic acid to zinc ratio in wheat grain, biological yield, and grain yield of Rakhshan cultivar. The study was set as a completely randomized design with three replications during 2017-2018 in a greenhouse. The treatments were: control, hard wood biochar, and rice husk biochar with three levels: 0.5, 1, 2.5% (w/w), compost at 2% (w/w), and integrated treatments including compost + hard wood biochar, compost + rice husk biochar, with 1% (w/w) of each one. Results showed a significant effect (p < 0.05) of treatments on grain yield, phytic acid to zinc ratio (p < 0.01), biological yield, and grain zinc concentration. The biological yield and protein content of wheat grain were not significantly different between control and the studied treatments. The phytic acid to zinc ratio of wheat grain was less than 25 for control, as well as for 1% and 2.5% of hard wood biochar, compost, and integrated treatments. Therefore, depending on their availability, the applications of 2.5% hard wood biochar, 2.5% rice husk biochar, 2% compost, or hard wood biochar+compost are recommended as organic fertilizers.