Distribution of iron and manganese in meadow forest - non-calcic brown and gray-brown podzolic soils of the himachal pradesh (India)

Abstract

Different forms of iron (total, free, reducible, extractable and exchangeable) and manganese (total, free, active, and exchangeable) have been fractionated from seven profiles of: (a) meadow forest; (b) non-calcic brown and (c) gray-brown podzolic soils of the Himachal Pradesh (India). Total and free Fe and total, free and active Mn generally show a pattern of distribution related both to the clay content, and to each other. This suggests that they are functions of the same pedological factors in these soils. The differences in the contents of total Fe and total Mn between the soil groups are due to the different proportions of these elements in the parent-materials. The abrupt increase of free Fe, and in some profiles of free Mn in illuvial horizons, is possibly a result of excess of mobilizing agent available just above these horizons. Reducible Fe does not show any definite pattern of distribution. Exchangeable Fe forms 17.6% of the extractable Fe. Exchangeable Fe 2+ forms a major portion (90%) of the total exchangeable Fe, but extractable Fe 2+ forms only 49% of the total extractable Fe. Significant correlations are found between exchangeable Fe and pH ( r = − 0.8759), and between exchangeable and extractable Fe ( r = + 0.7822). Exchangeable and extractable Fe are comparatively low in these soils. The proportions of free and active Mn oxides are related to total Mn whereas exchangeable Mn is related to soil organic matter.