Soil Factors and Grassland Type Relationships in the Subhumid Zone of Northern Benin

Soil samples collected under different grassland vegetations were studied. Mineral components were closely related to organic matter (OM) level, which was significantly correlated with cation exchange capacity (CBC). OM had an estimated average CEC of 1.8 me./100 g soil. Total exchangeable bases depended on both organic and mineral components and pH. Exchangeable K and Na depended mostly on clay and silt fractions, Cluster and principal component analysis enabled recognition of 5 clusters each grouping different grassland vegetation types. This confirms that soil factor analysis supports the field descriptions of the study soils but is inadequate to discriminate floristic composition at local level.