Abstract
Data for CEC, clay and organic carbon contents were collected for 30 profiles in Jos plateau, northern Nigeria. Multiple regression analyses were used to examine the relationships between CEC and clay and organic carbon, to estimate the CEC of clay and organic carbon, and the contributions of clay and organic carbon to the total CEC of soils. The data were partitioned by soil horizons, parent materials, slope positions, and the FAO soil map of the world sub-units to test for distinct relationships within groups. The multiple regression analysis indicated that about 58% of the variations in CEC of Jos plateau soils could be attributed to the variations in both the clay and organic carbon contents, with the clay having a CEC of 12 and the organic carbon 179 mEq 100 g-1. Grouping the soils by parent materials and soil map of the world sub-units gives better results than grouping by horizon or slope position in estimating CEC. Slope position is best used to define soils of different CEC characteristics when the landscape is resolved into two main components the valley and lower slopes, and the middle and upper slopes. Using these two main categories of slope position gives better estimates than grouping by parent material or soil sub-unit.
