Effect of Organic Matter on Different Forms of Manganese, Iron and Cobalt in Soils

Abstract

Manganese moved from insoluble forms ( CO₃ , CFeOX, residual, MnOX) to more plant-available forms (exchangeable and organic). Manganese as percentage of total soil Mn in different fractions was in the order residual > MnOX > AFeOX > CFeOX > OM > Ex+W > CO3. Increasing organic matter moved iron fmm CFeOX and  C0₃ fraction to residual fraction and less &luble and intermediately fractions. More than 50% of total Fe was associated in the mineral fraction (residual fraction) in all the soils. The results showed that native and added Co was mainly retauied in soluble and intermediately soluble fraction of MnOX and AFeOX. Cobalt in various Gactions was in the order: Residual > Ex+W > AFeOX > MnOX > OM > CO₃ > CFeOX.