DISTRIBUTION OF VARIOUS FORMS OF ALUMINUM, IRON AND MANGANESE IN THE ORTHIC GRAY WOODED, GLEYED ORTHIC GRAY WOODED AND RELATED GLEYSOLIC SOILS IN MANITOBA

Soil color and other morphological features have definite limitations in differentiating Gleyed Gray Wooded from related Gleysolic soils of similar morphology. Iron and manganese data could provide guides for their separation. Oxalate-extractable to dithionite-extractable iron ratios differed considerably in or below the B horizon. The ratios for the BC horizons were 0.09 for an Orthic Gray Wooded, 0.29 to 0.45 for three Gleyed Orthic Gray Wooded and 0.55 to 0.93 for three Gleysolic soils. Dithionite-extractable iron to clay ratios were relatively constant in the Orthic Gray Wooded, a slight minimum occurred in the Bt horizons of the Gleyed Orthic Gray Wooded soils, and a maximum occurred in AB or B horizons of the Humic Eluviated Gleysols and the Fera Humic Gleysol. Total manganese distribution could aid in the separation of these soils; the maximum accumulation of manganese occurred in the Ae and Bt horizons of the Orthic Gray Wooded, in the Bt horizons of the Gleyed Orthic Gray Wooded, and in the C horizons of the associated Gleysolic soils. Aluminum distribution (dithionite- and oxalate-extractable) did not differ among these soils, indicating that it was not affected by differences in drainage regime.