The characteristics and suitability of the soils of some major cocoa growing areas of Nigeria: Tung lga of Cross River

Abstract

The soils of the major cocoa growing district of Etung Local Government Area of Cross River State were surveyed using a flexible grid method to assess the  suitability of these soils for cocoa production. This study  was carried out as part of efforts to revitalize cocoa production in Nigeria. Both the linear and square root  parametric models of suitability assessment were used for the evaluation exercise. From the computed values of the current index productivity (1.80 12.75), all the mapping units delineated from the exercise were currently not suitable (N2) for cocoa production. The limiting factors identified include high rainfall (> 2500 mm annually) and relative humidity (65.5% - 85%), low fertility (N, P, K, Ca, Mg) resulting from nutrient leaching, low pH (3.45 4.90 in KCl) and cation exchange  capacity (1.67 10.75 cmol kg^-1), and low to toxic  concentrations of Fe, Mn, Cu and B in the soils. However, the values of potential productivity index (13.41 - 45) suggested that most of the mapping units will be marginally suitable (S3) for cocoa production with adequate application of appropriate fertilizers and suitable soil management practices. This will require a carefully designed fertilizer trial to ascertain the optima fertilizer level, fertilizer types and application methods.

Key words: Land suitability, Cocoa production, Soil fertility, Soil management and Etung LGA.