Agronomic biofortification is a new strategy for fighting zinc (Zn) deficiency in human. Biofortification can improve Zn uptake by plants by changing Zn status in soil. Crop residues can influence nutrient cycle and soils physical and chemical properties it can use as powerful tool in agronomic biofortification. This study was conducted to evaluating effects of crop residues on Zn concentration in wheat grain and evaluating the possibility of using hyperaccumulator plant residues as Zn source in agricultural lands. In the first part, five crop residues (sunflower, clover, sorghum, safflower, bean) were used. Two wheat cultivars including Kavir (as a zn inefficient cultivar) and backcross Rushan (as a zn efficient cultivar) were planted in the in the residue treatments. Wheat yield, Zn concentration and Zn total content in root, shoot and grain and phytic acid concentration and grain protein were measured. In the second part of the study, Thlaspi caerulescens and Amaranthus retlofelexus a Zn hyperaccumulator were planted in high and low Zn concentrationsoils. After plant harvest Zn concentration in the roots and shoots were measured. Results show that bean residuses had highest effect on Zn concentration in soil. Roots, shoot and grain yields were higher in kavir than backcross rushan. All crop residues significantly increased wheat shoot yield but did not significantly affect wheat grain yield. Zinc concentration in backcross roshan grains as Zn efficient cultivar was higher than kavir grain. The phytic acid to Zn molar ratio was greater than 15 in both wheat cultivars indicating low Zn bioavailability. In addition, crop residues caused significant increase in Zn grains compared to the control treatment. Sorghum and sunflower treatments had the greatest effects and bean and clover treatments had the lowest effect on Zn concentration. The phytic acid to Zn molar ratio decreased in both cultivar as result of residues treatments. Sorghum, sunflower and safflower had the highest effect on grain Zn concentration but phytic acid to Zn molar ratio was highest in these treatments too. Grain protein concentration was higher in backcross rushan than kavir cultivar and Bean and clover residuse inceased grain protein concentration significantly due to adding more nitrogen to the soil The results in the seconds part of the study showed that Zn concentration in Thlaspi caerulescens and Amaranthus retlofelexus roots and shoots were higher than nonaccumulator plants. Thlaspi caerulescens shoot that grown in the high Zn concentration soil can potentially adding 10 mg Zn in to one kilogram of soil that is around 78 kg zinc sulfate. Thus Thlaspi caerulescens is a good
