Quantitative and Qualitative Soil Water Resources Potentials and Soil Assessment of River Onyongo Drainage Basin for Agricultural Use-Oju Local Government Area - Benue State, Nigeria

To assess the quality of River Onyongo catchment area for agricultural purposes. Field and laboratory assessment was carried out.

Water resources potential assessment was carried out in part of River Onyongo catchments area. The topographical map was used to carve out the study area. Geological mapping of the study was carried out by compass. Field permeameter pits were established in four locations within the study area to determine the coefficient of permeability of sub-surface soils/lithology by Darcy Law. Depth to water table was measured in some selected hand-dug wells. Discharge measurement of River Onyongo rainy season was 199,888.12 litres/second and 2,770.62 litres/second in dry seasons while River Ichow (bridge) had 354.3 litres/second in the rainy season and 195.43 litres/second at the upstream; there was no flow during the dry season. Water samples were collected in the various locations in the study area and analysed in the laboratory. The relief of the study ranges from 100 m to 223 m above mean sea level. The Sodium Absorption Ratio (SAR) of the water sample ranged from 0 – 10 mg/l indicating that water can be used on all crops and all soils. The coefficient permeability/lithology of the study area ranged from 0.36 – 29.5 m/day corresponding to fine-grained sand to medium-grained sand – coarse-grained sand. Recommendations for the use of water for optimal agricultural purposes and production in the study areas were made.