Correlation of Nature of Soil Acidity with Different Forms of Iron and Aluminium intwo Alfisols and an Inceptisol of Nagaland

摘要

Fifteen acid soils of Nagaland representing selected soil series were studied to characterize the natureof acidity in relation to different forms of iron and aluminium. The mean contents of iron and aluminium were extracted by various extracting reagents and were found to be in the descending order as followed : dithionite > oxalate > pyrophosphate > ammonium acetate > KC1. The electrostatically bonded EB-H+ and EB-A1~(3+) acidity constituted 13 and 87 per cent of exchangeable acidity while EB-H+, EB-Al~(3+), exchangeable and pH-dependent acidities comprised 2, 12, 14 and 87 per cent of total potential acidity. Forms of acidity showed significant correlation with pH and different forms of Fe and Al in soils. Among the soil properties, pH and different forms of Fe and Al caused most of the variations in different forms of soil acidity but the effect of different forms of Fe are more active and directly participate in the formation of different forms of acidity.