Morphogenesis and classification of the yellowish-brown soil at Agbarho, Bendel State, Nigeria
Keywords:
Morphogenesis, yellowish-brown soil, sand texture, mineral, rainfall.Abstract
Two profiles of Agbarho soil were analysed chemically, physically and mineralogically. The soil is located in the heavy rainfall, thick vegetation zone of Nigeria (average annual rainfall 2500mm).
The soil has a yellowish-brown colour, sandy loam to loamy sand texture with low silt content. The heavy rainfall has effectively contributed to the leaching of the basic cations from the soil. Calcium is the dominant exchangeable cation with values ranging from 0.1 to 1.8 m. eq/100g soil.
Kaolinite is the dominant clay mineral. Considerable quantities of mica, vermiculite, quartz and interstratified materials are present in the clay fraction of the soil. The silt fraction is dominated by quartz with some feldspars.
It is probable that the parent sediment of Agbarho soil was arkosic, and that the weathering of this parent sediment resulted in the formation of the minerals present in the clay and silt fractions.
Agbarho soil would classify as Etinan series following Vine's description; as Sols Ferrallitiques Lessives of the French classification system; as Oxisol of the Soil Taxonomy; and as Xanthic Ferralsol of the FAO/UNESCO mapping legend.
