SANDSTONE-DERIVED SOILS OF A CATENA AT IPERU, NIGERIA |
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| Authors: | J A OGUNWALE T I ASHAYE |
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| Institution: | Department of Agronomy, University of Ibadan, Ibadan, Nigeria.;Acting Director, Institute of Agriculture Research and Training, University of Ife, Moor Plantation, Ibadan, Nigeria. |
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| Abstract: | Chemical and mineralogical properties of five soil profiles of a catena in Iperu, Western State of Nigeria, are reported. The pH values of the subsoils are extremely acid. Acidity decreases with improved drainage in the subsoils (pH 4.0–5.8). The cation exchange capacity (C.E.C.) of the soils range from 3.0 to 16.2 me/100g of soil. The silt: silt+clay ratio, calcium: magnesium ratio and Fe2O3:Al2O3 ratio are used as weathering indices. The low values of the silt: silt + clay index indicate that the soils must have undergone advanced weathering. The magnitude of the Ca: Mg ratio indicates that more calcium than magnesium is available in the soils. The values for sodium and potassium are extremely low. More iron than aluminium was extracted from the soils by the dithionite-citrate method. Kaolinite is the most abundant clay mineral. Halloysite, interstratified clay materials, vermiculite, quartz, and mica are present in considerable amounts. The silt fraction in which quartz is the most abundant mineral, also contain some kaolinite and mica. |
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