Study of the Chemical Behavior of Zinc from Different Sources in Calcareous Soils

A study of the effect of adding three different zinc sources on the kinetics of zinc release and adsorption in soil. A laboratory experiment was conducted using three soils of different texture . The soils were incubated with zinc added at three concentrations (0, 10 and 20) mg Zn2+ L−1 in the forms chelated zinc Zn-EDTA, organic zinc Zn-HA, and mineral zinc ZnSO4·7H2O. To calculate the amount of releasable and dissolved. An adsorption experiment was also performed on soil samples by taking 5 gm of soil and adding zinc at concentrations 0, 5, 10, 15, 20 and 25 mg Zn2+ L−1. Results also showed that the lowest values of maximum adsorption and binding energy were for the chelated zinc Zn-EDTA treatment compared with organic zinc Zn-HA and mineral zinc ZnSO4·7H2O . Results also showed the superiority of the chelated zinc Zn-EDTA source compared with the other sources organic zinc Zn-HA and mineral zinc ZnSO4·7H2O, the rate of zinc release increased for both added concentrations (10 and 20) mg Zn2+ L-1 .The percentage of increase for the chelated zinc Zn-EDTA treatment reached 39.748, 47.144 and 46.617% compared with the organic zinc Zn-HA treatment, and reached 88.439, 107.028 and 109.997% compared with the mineral zinc ZnSO4·7H2O treatment at the concentration of 10 mg Zn2+ L−1 treatment for all study soils (S1, S2 and S3) respectively.