Effects of Growing Corn Plant and Some Fertilizers on Zinc Fractions in a Calcareous Soil.
Adil Reyhani Tabar, Mohamad Ardalan, Najaf Ali Karimian, and Gholam Reza Savaghebi. Univ of Tehran, Karaj, Iran
A factorial experiment and CRD design with two replicates was carried out to examine the influence of 3 levels of vermicompost(0,5 and 20 gm.Kg-1), 3 levels of N(0,60 and 120 mg.Kg-1 as urea) and 3 levels of Zn( 0,5 and 10 mg.Kg-1 as ZnSO4.7H2O) with and without corn plant(ZeaMays cv. SingleCross704 )on the various fractions of soluble plus exchangeable (ZnEX2), Carbonate adsorbed (ZnCar), Organic matter Complexed (ZnOm) Manganese Oxide bound (ZnMnox), Amorphous iron Oxide bound (ZnAFeOX). Crystalline oxide associated (ZnCFeOX), and residual (ZnRES) Zinc in a Calcareous Soil (Termic Calciorthids). Application of Urea without corn plant had no significant effect on Zinc fractions, but with plant urea significantly increased ZnOm, ZnMnox, ZnAFeox and ZnCFeOX and non significantly decreased ZnRES. Urea significantly caused an increase in dry weight, zinc concentration and total zinc uptake by corn plant. Application of ZnSO4, while significantly increased the Concentration of all forms of Zn, had a pronounced effect on Zn-RES with and without growing plant. ZnSO4 application had no significant effect on dry weight of corn, but significantly increased zinc concentration and uptake in plant. Vermicompost increased the ZnEx2 and ZnOm without plant and increased ZnCar, ZnOm, ZnAFeox, ZnCFeox with plant and dry weight, zinc concentration and uptake in plant. Growing corn while increased ZnOm, cause a significant decrease in other zinc fraction except Zn-RES. Overall conclusion was that 43- 50% of the applied ZnSO4 was converted to residual form with and without plant. It was also concluded that conversion of applied ZnSO4 to residual form was mainly responsible for retention of this fertilizer in calcareous soil. Significant positive correlations between zinc forms indicated that they are possibly in dynamic equilibrium with each other the chemical forms of an element in soil. Keywords: Zinc forms, Sequential extraction, calcareous soil, Corn, Zinc Sulfate, Urea, Vermicompost.