Abstract

In this study, soil samples were collected from 0 to 15 cm and 15 to 45 cm of secondary forest, mixed plantation, natural fallow and sole plantation. Soil samples were chemically analyzed using standard methods for organic matter, nitrate-nitrogen, pH, bulk density and available phosphorus. The results were statistically analyzed and index of deterioration was also calculated for the soil properties. Mixed plantation appeared to resemble the secondary forest in soil properties except available phosphorus. There is significant degradation of available phosphorus in mixed plantation which was probably due to the high uptake of nutrients for production of pods, nuts and beans of cocoa and kola trees that co-exists to form the mixed plantation. The results suggested that establishment of sole plantation was not a viable ecological approach to soil management and conservation but mixture of trees proved advantageous to soil. Natural fallow in the absence of incessant bush fire also appears to be a sound land-use technique in conserving soil properties.

Key words: Index of deterioration, soil productivity, organic matter, litterfall, natural fallow, mixed plantation.