Characteristics and Constraints of Some River Flood Plains Soils to Crop Production in Southeastern Nigeria

Characteristics of some river flood plain soils in Southeastern Nigeria were assessed for their potentials and constraints to crop production. Soil texture varied remarkably from loamy sand in Imo (IMR) and Cross River (CRR) through sandy loam in Igwu (IGR) to sandy clay loam in Qua Iboe (QIR) river flood plains. Soil reaction ranged from strong to moderate with pH values averaged 4.9-5.2. Organic matter contents varied from moderate (16.9 g kg-1), to high (28.1 g kg-1). Total N (0.4 – 0.7 g kg-1), exchangeable Ca (1.15-1.76 cmol kg-1), K (0.07-0.8 cmol kg-1) and CEC (1.72-2.83 cmol kg-1) values were low and less than their critical levels in the soil. In contrast, exchangeable Mg level was high while, available P and percent base saturation levels varied from low to moderate: 7.28-39.79 mg kg-1 for P and 43.3-59.7% for base saturation. The main constraints of these flood plains to sustainable crop production are therefore, the low chemical fertility (moderate to high acidity, low Ca, K, CEC and total N concentrations). However, short season crops (vegetables) can be grown at the present level of subsistent farming. Ordinarily, fertilizer and lime would be recommended as measures to increase yield of crops, but these inputs are both unaffordable and unavailable at critical periods. Therefore, the farmers are encouraged to harness cheap resources found on the farms such as mulch and biofertilizers, to improve soil chemical fertility rather than rely on inputs that are normally not accessible.