Soil Mineralogical Characterization of Selected Carmine Alfisols and Plinthic Inceptisols of Funtua, Nigeria

This study aimed to characterize the mineralogical properties of soils formed over a basement complex parent material in the Northern Guinea Savanna agro-ecology of Nigeria. The selected study site was in Funtua, Funtua Local Government Area of Katsina State, Nigeria. Soil boundaries were delineated, and three soil individuals were identified, namely, Soil-map-unit-red-deep (SMURD) which covered extensive part of the study area occupying 1755.17 ha (66.50 %), soil-map-unit-plinthic-shallow-1 (SMUPS1) occupying 708.70 ha (26.85 %), and soil-map-unit-plinthic-shallow-2 (SMUPS2) occupying 175.60 ha (6.65 %). On each soil individual, a pedon was sited, described, and sampled from genetic horizons. Soil samples collected were prepared and subjected to laboratory mineralogical analysis with the employment of x-ray diffractometer to determine the dominant clay-sized minerals present in the soils. Evaluation of the soil individuals indicate SMURD as very deep (>150 cm) and well-drained, SMUPS1 was shallow (25 - 50 cm) well-drained, and SMUPS2 was well-drained and had a moderate depth of soil materials (71 - 80 cm). It was observed that the soil individuals had mixed mineralogy, which was associated with different rock types and minerals constituting the Basement Complex. The soils were formed under uniform climatic conditions and expected to have undergone a similar rate of weathering. The wide variation in mineral composition of the soils as was attributed to the basement complex characteristics however gave two dominant clay-sized minerals: Kaolinites (and its polymorphs - dickite, clinochrysotile, greenalite) and zeolites.