Effect of Applying Sunflower Residues as a Green Manure on Increasing Zn Concentration of Two Iranian Wheat Cultivars in a Pb and Cd Polluted Soil

This research was investigated to evaluate effect of applying sunflower residues as a green manure on increasing zinc (Zn) concentration of two Iranian wheat cultivars in a Pb and cadmium (Cd) polluted soil. Treatments included the application of sunflower residuals grown in a Zn-polluted soil  at two levels of 0 and 8 t/ha, two wheat cultivars  in a soil contaminated with Pb (0, 400 and 800 mg Pb/kg soil) and Cd (0, 5 and 10 mg Cd/kg soil). After 7 months of the experiment. Plant Pb, Zn and Cd concentrations were measured using atomic absorption spectroscopy.  The highest root and shoot Zn concentration of wheat plant was belonged to the      Back cross cultivar. Addition of 8 t/ha sunflower residues in soil without Pb and Cd pollution increased the root Zn concentration of Back Cross and Kavir  cultivars by 12 and 16%, respectively. The highest and lowest Zn translocation factor of wheat plants was belonged to Back Cross and Kavir cultivars, respectively. Applying sunflower residues has a significant effect on increasing plant Zn concentration and can be useful as a suitable way to increase Zn concentration of wheat grown in Zn deficient and heavy metal polluted soils.