Effect of Water Regimes and Organic Matter on the Transformation of Applied Zinc in Soils

A laboratory incubation experiment was conducted with two rice growing soils (Aquic Ustochrept and Typic Natrustalf) to study the influence of water regimes and organic matter on the recovery of applied Zn. The recovery of zinc in various fractions was always higher in the Aquic Ustochrept than in the Typic Natrustalf. The magnitu.de of transformation of applied zinc to organically, amorphous Fe-oxide and Mn-oxide bound fractions was relatively higher under the continuously than under the alternately submerged conditions and the results were reverse in respect of water soluble plus exchan,geable and crystalline Fe-oxide bound fractions. Application of organic matter enhanced the transformation of applied. Zn to Mn-oxide, organically and amorphous Fe-oxide boundforms but it discouraged such transformations to the water soluble plus exchangeable and crystalline Fe-oxide fractions. At the end of 48 days of incubation study, higher amounts of Zn were recovered in Mn-oxide. organically and amorphous Fe-oxide boundfractions in 5 mg Zn kg⁻¹ than in 10 mg Zn kg⁻¹) treatment but the reverse was true in respect of the other two Zn fractions.