A clear understanding of soil characteristics and their appropriate classification are essential for efficient land use and increased productivity. The present study was carried out to obtain the fertility capability classification (FCC) of the soils overlying the basement complex in a toposequence in north eastern Nigeria and to serve as baseline data for soil management. Soils on four topographic positions identified on porphyritic granite (PG), pegmatite (PT) and granite-gneiss (GG) of the basement complex in Taraba State of Nigeria were assessed. Twelve pedons were studied in all, four along the toposequence on PG, PT, and GG. At the type and substrata type, sandy and loamy group dominated. Ustic soil moisture regime, exchange acidity (fixing available phosphorus) and low organic carbon limited the entire soils across the basement complexes restricting rainfed crop production to one season per annum except with irrigation practice. Poor drainage was a limitation across the soils on pegmatite. The FCC rated PG and GG soils as SLdeam (sand over loam and limited by moisture, effective cation exchange capacity, aluminium toxicity and organic carbon) and Ldam (loam type and substrata characteristics limited by moisture, aluminium toxicity and organic carbon), and PT and PT soils as Sdamg (sandy type and substrata type restricted by moisture, aluminium toxicity, organic carbon, drainage). Ridge construction, organic and mineral fertilizer applications are essential management practices required for sustainable use of these soils.

The properties of soils in an area are defined by the interaction between lithology and other factors of soil formation. Of the five factors of soil formation, climate is most important in the control of the distribution of crops in Nigeria, and oil palm is not an exception. The study was carried out to evaluate the suitability of land in Cross River State for oil palm production, and make appropriate soil management recommendations for improved production. Eight slope transitions were identified and two soil profile pits were sunk in each transition. Sixteen profile pits were used for the study. Currently, the well-drained high elevation soils are moderately suitable (S2) for oil palm cultivation; however, most of the well-drained soils in the higher elevation ranges in the southern agricultural zone are potentially highly suitable (S1). The central and southern agricultural zones are more suitable for oil palm cultivation. The poorly drained and low elevation areas in the three zones are not economical for the cultivation of oil palm and should be put to the cultivation of sugar cane and paddy rice.