Characterization and P Fixation of Soil on Mt.Cameroon Slopes

Phosphorus (P) is cited as one of the six major plant nutrients alongside Nitrogen (N), Potassium (K), Sulphur (S), Calcium (Ca) and Magnesium (Mg) but it is generally believed that tropical soils fix most of the applied P into forms unavailable to plants. Evaluation of P fixing capacity of the highly agricultural soils around Mount Cameroon, was done and so contributed to the prediction of P additions as indicated in this book. Molyko soil series is a young volcanic soil, made up of five horizons in the profile 200 cm deep. The soil is moderately acidic with pH ranging from 5.7 to 6.1, moderately organic (1.0 to 4.0 % organic carbon), silt loam textured, with silt content between 50 and 60 % and low clay content (between 16.7 and 25.3 %). Bray-2 available P is very high in the upper horizons (0-100 cm), more than 100 mg/kg and very low in lower horizons (100-200 cm), less than 12 mg/kg. Total nitrogen (0.08-0.27 %), exchangeable calcium (4.87-12.83 cmol/kg), sodium (0.09-0.27 cmol/kg) and potassium (0.19-2.77 cmol/kg) all decreased with depth.