The soils of the lower Niger floodplain at Ogbaru are intensively cultivated, as it is a major food basket of the State and surrounding regions. The soils were studied using profiles along the slope. Profiles were dug along the upper-slope, middle-slope and toe-slope at Atani. Soil samples collected from the pedogenetic horizons of the three profiles were characterized and classified. The soils developed on the alluvial deposits and are deep, yellowish brown, mottled and loamy. Total sand dominated the upper-slope and toe-slope while clay increased with depth at the toe-slope, silt dominated the soils at the middle-slope. Soil pH values range from 4.8-6.2 and increase slightly with increase in profile depth. Exchangeable bases were generally high while organic carbon and total nitrogen were low. Available phosphorus was very low to high ranging from 0.93-31.71 mg kg-1 while base saturation of the soils was high. Soil classification was made using USDA Soil Taxanomy and correlated with FAO/IUSS World Reference Base. The soils were classified as Entisols and Inceptisols. In FAO/IUSS World Reference Base Gleysols, and Anthrosols were identified. Soils at the upper-slope (ATA1) were classified as Aquic Quartzipsamments (Endoarenic Gleysols). Soils of the middle-slope (ATA2) were classified as Typic Plagganthrepts (Hypereutric Anthrosols) while soils of the toe-slope (ATA3) were classified as Fluventic Endoaquepts (Hypereutric Gleysols).
Keywords: Characterization, classification, agricultural potential, floodplain.