Concentration and distribution of iron and manganese fractions in alabama ultisols
2004
Tazisong, I.A. | Senwo, Z.N. | Taylor, R.W. | Mbila, M.O. | Wang, Y.
Information on metal forms and contributions of soil properties on metal distribution in Alabama soils is either limited or meager. This study chemically partitioned and evaluated soil Fe and Mn distributions and applied stepwise multiple regressions to identify the soil properties influencing their distributions in some Alabama Ultisols. Iron and Mn distributions among metal fractions were generally dependent on total metal content, soil properties, and degree of chemical weathering. Distributions among metal fractions showed that Fe was mainly in the residual fraction (> 85%), whereas Mn was predominantly oxide-bound and in the residual fraction (> 90%). The proportion of Fe fractions in the soils was in the order: residual > oxides (crystalline FeO, amorphous FeO, MnO) > organic > exchangeable, whereas Mn was in the order: oxide-bound (MnO, amorphous FeO, crystalline FeO,) > residual > exchangeable > organic fraction. Stepwise multiple regression analysis showed that pH accounted for 33% of the total variability in exchangeable Fe, whereas SOM accounted for 47.1% of the total variability in exchangeable Mn. Clay and sand contents accounted for 42.2 and 52.3%, respectively, of the total variability in the residual Fe fraction, whereas silt accounted for 19.7% of the total variability in residual Mn distribution in these soils.
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