Characterization and classification of some soils formed from coastal plain sands origin in Edo State, Nigeria

The aim of this research was to map and classify some soils of coastal plain sands origin in Edo State, Nigeria. The study covered two areas, including Site A (4 hectares) and Site B (12 hectares). The methodology used was a systematic soil survey using a rigid grid at detailed scales (1:5000 for Site A and 1:10,000 for Site B), with two mapping units delineated at each site. A representative pedon was excavated in each mapping unit, described, and sampled for analysis. Soil samples were analyzed using standard laboratory methods, and the data were processed with descriptive statistics. Soil classification followed USDA soil taxonomy, the World Reference Base for Soil Resources, and local systems. The morphological properties showed reddish soil colors when moist, with structures varying from single grain crumb to sub-angular blocky, and textures from sand to sandy clay loam. The content of sand, silt, and clay ranged from ≥742.0 to ≤886.00 g/kg, from ≥15.00 to ≤26.00 g/kg, and from ≥88.00 to ≤190.00 g/kg, respectively. Meanwhile, pH, organic carbon, cation exchange capacity, and base saturation ranged from ≥5.24 to ≤5.58, from ≥4.80 to ≤13.70, from ≥6.71 to ≤11.90 cmol/kg, and from ≥9.80 to ≤21.60 cmol/kg, consecutively. Pedons 2A and 2B were classified as Rhodic kandiudults by USDA, Rhodic Nudiargic Acrisols (Arenic, Vetic) by WRB, and locally as the Orlu series. Pedon 1A was classified as Typic Udipsamments by USDA, Eutric Rhodic Arenosols (Transportic) by WRB, and locally as the Ahiara series. Pedon 1B was classified as Typic Eutrudepts by USDA, Eutric Rhodic Cambisols (Arenic, Ochric) by WRB, and locally as the Kulfo series.