Influence of Parent Materials and Land Use on Exchangeable Cations in a Tropical Environment

Present research was undertaken to examine the influence of parent materials and land use on exchangeable cations in Edo state, Nigeria. This investigation was carried out with the following objectives (i) to examine the status of exchangeable cations in the soils (ii) to determine the difference in the exchangeable cations of soils amongst the different land use types in Okodobo Village. Eighteen soil samples (0-15 cm and 15-30 cm depths) were collected from three study sites viz., Secondary forest (control site) and Plantain and Oil palm (treatment sites) plantations. Exchangeable cations were analyzed using standardized methods and analyzed employing soil quality index and student t -test. The analytical results confirmed that the status of Ca++, Mg++ and Na+ were deficient, K+ was however not lacking. Student t-test revealed that there was significant difference of exchangeable cations between secondary forest and plantain land uses. Similarly, significant difference existed between plantain and oil palm land uses. Further, t-test revealed that there was no significant difference of exchangeable cations between secondary forest and oil palm land uses. Exchangeable cations decreased from surface to subsurface soils in secondary forest and oil palm land uses but increased down the soil profile in plantain land use. This research reveals the intense impact of parent materials and land use on exchangeable cations in the study area. Keeping in view the high acidic levels and low status of Ca++, Mg++ and Na+ in the soils, organic matter and agricultural lime applications are recommended respectively.