Assessment of Selected Chemical Properties of Soils of the Sokoto-Rima Floodplains at Sokoto, Nigeria

The levels of soil chemical properties largely determine the suitability of soils for agriculture. This study examined selected chemical properties of soils in the Sokoto-Rima floodplains in Sokoto, Nigeria. Two locations were selected for the study (Kwalkwalawa and Nasarawa), both within the Sokoto-Rima floodplains. Soil samples were collected from the genetic horizons of profile pits dug in the two locations and analyzed for physical and chemical properties using standard laboratory procedures. Texturally, the soil varied from sandy loam to loam sand and silt clay loam. The values of sand, silt, and clay contents were significantly (p < 0.05) different between the two locations. Soil pH values ranged from moderately acidic to strongly alkaline (5.5 - 8.7) and were significantly (p < 0.05) different between the two locations. Soils in both floodplains were rated low in organic carbon (< 10 g/kg) and total nitrogen (< 1.5 g/kg), while available phosphorus was rated low to high. Soils in Nasarawa floodplains had significantly (p < 0.01) higher exchangeable potassium (K) and sodium (Na) levels than soils in Kwalkwalawa floodplains. Soils in Kwalkwalawa floodplains were rated low to high in exchangeable K and medium to high in sodium (Na), magnesium (Mg), and calcium (Ca). However, soils in Nasarawa were rated low to high in K, Na, Ca, and Mg. Exchangeable acidity values were rated low in both locations (< 1.0 cmol/kg). Cation exchange capacity (CEC) was significantly (p < 0.05) different between the two locations, with values rated low to high (< 6 to > 12) in both locations. Generally, soils in Nasarawa floodplains were more fertile than those in Kwalkwalawa floodplains. The low fertility in terms of organic carbon and exchangeable bases will require the adoption of proper management practices, including organic and inorganic fertilizer application, to sustain soil fertility.