Evaluation of soils on a toposequence formed from the coastal plain sands of the Imo river basin, Southeastern Niger

Abstract

Due to the increasing land degradation in southeastern Nigeria – with particular reference to the ubiquitous gully network in the region – selected soils formed from the Coastal Plain Sands of the Imo River Basin were evaluated and characterized to determine their potentials and capabilities. , Three profile pits were consequently dug on the upper slope (Umuariam), -mid-slope (Umulogho), and foot slope (Umungwa) of three towns on the Imo River Basin underlain by the coastal plain sands. The soil color ranged from greyish brown (5 YR 5/2) to dull brown (7.5 YR 5/3) in the topsoil and from dull orange (5 YR 6/4) to orange (5 YR 6/7) in the subsoil. The soils had sandy topsoil and relatively more clayey subsoil. The pH (in KCl) ranged from very strongly acidic (4.5 – 5.0) to moderately acidic (5.1 – 6.0). They had low organic matter, low total nitrogen, low ECEC, low Al saturation, and moderate base saturation. The soils of Umuariam (Upper Slope) and Umulogho (Mid Slope) were classified as Typic Hapludults (Chromic Acrisols), while that of Umungwa (Foot Slope) was classified as Typic Udipsamments (Rubic Arenosols). Umuariam had a USDA land capability class of IIes and a USBR land capability class of 2v/C. Umulogho and Umungwa both had a USDA and USBR capability class of IVs and 3v/C respectively. Though moderately to marginally irrigable, the soils can still produce increased and sustainable agricultural yield if the appropriate land use and husbandry practices are adopted, with particular reference to erosion control, organic manure, lime, and fertilizer application.