A Case of Fertility Status Evaluation and Classification of Floodplain Soils at Onumirikwa River, Ulakwo, Imo State Southeastern Nigeria
One major challenge of intensive crop production practice in riverine arears is low crop yield due to chemically infertile soils, attributed to poor soil fertility management. This study provides information on fertility status and morphology of floodplain soils using Onumirikwa Ulakwo River, Owerri, Nigeria. In three geomorphic units: (i) crest (ii) terrace and (iii) back-swamp soil was sampled from horizons of three profile pits and analyzed for physico-chemical and morphological properties. Systemic soil categorization was carried out according to USDA classification system. Results showed that Onummirikwa Ulakwo floodplain soil is characterized with sandy loam soil < 1.5 km from the water body. Soil pH, organic carbon content, available phosphorus, and cation exchange capacity were relatively low. Apart from the soil organic carbon content most of the evaluated chemical properties marginally varied in all geomorphic units. Soil aluminum content was relatively high in the back-swamp. These characteristics indicate the soil of this site is chemically infertile for crop production. Soil morphological features show that the floodplain has argillic and kandic horizons within profiles. It is freely drained with no sombric horizons and possesses progressively decreasing SOC content with depth; a clear indication of Kandiudults sub-group of soil. Based on reference soil group of the World Reference Base, the soil of this floodplain is Acrisols. Organic fertilization programmes to local farmers, who use this floodplain for crop production are recommended.