Abstract

Changes in surface reactivity produced by different types of liming in a Chilean Andisol were determined. Barros Aranas soil with 53% aluminum (A1) saturation and 4.8 pH was incubated with different amounts of calcitic and dolomitic lime. Each cmol of calcitic or dolomitic lime applied per kg of soil increased the pH with 0.13 and 0.16 units, respectively. Consequently, the decrease in A1 saturation was higher with dolomitic than with calcitic liming material. The zero point of charge (ZPC) increased from 4.2 in unlimed soil to 4.6 and 4.8 in limed soil, while the point of zero salt effect (PZSE) decreased from 4.5 to 4.0 and 3.5 with calcitic and dolomitic lime, indicating an increase in negative charge. But, isoelectric point (IEP) values measured by electrophoretic migration suggested that the external charge only changed by treatment with calcitic liming materials. In both treatments, the acidity constant decreased, and consequently phosphorus (P) adsorption capacity also decreased.