Laboratory and greenhouse studies were undertaken to determine the usefulness of K Quantity, Intensity and Capacity
factors in evaluating K supply capacities and in predicting K uptake by maize in 14 representative soils of South
Western Nigeria. The results showed that the activity ratio was a poor index of the available K and was incapable
of correct prediction of K uptake during prolonged cropping. The potential Buffer Capacity was higher in the soils
on basement complex than in soils derived from sedimentary origin, indicating that depletion of K on cropping will
be faster in soils derived from sedimentary rocks than those on the basement complex. The results also showed that the
'fixed K' Quantity factor and the Potential Buffer Capacity could provide useful information in characterising the
differential Buffer behaviour of soils
