ABSTRACT

A study was carried out to compare the effect of some forest tree species (Gmeelia arhorea, Pinus cariheae, Pentacletihra macrophylla, Anthonota macrophylla, Irvingia womboIu and Tectona grandis) on the soil exchangeable cations. Surface (0- I 5cm) soil samples were collected from plantations in the Forestry Research Institute of Nigeria, Ahiaeke. Soil exchangeable Ca beneath (J,neli,,a arborea was significantly higher than the rest. There were negligible differences among the species apart from Gmelima arborea in quantity of the exchangeable Ca. soils under Pinus caribeae and (Gmelina arborea showed significantly higher exchangeable K than in the other treatments. Exchangeable Mg under Gmelima arborea was higher than under Anthonola macrophlla and Pinuis caribeae. Exchangeable acidity was highest in Irvingia wombolu and Peniaclethra inacrophylla and significantly different form the control. Gmelina arboreae showed significant improvement in ECEC while percentage base saturation was not significantly different for pinus carbeae and the control. The observed differences in the soil exchangeable cations under these trees implies that some can improve the nutrients and can be used to rehabilitate areas deficient in these nutrients.