Review of the Fertility Status of the Wetlands of the Lower Anambra River Basin for Sustainable Crop Production.

The Wetlands of the Lower Anambra River Basin have been subjected to continuous crop production for a long time without adequate fertility restoration strategies. There was therefore the need to re-evaluate the soils health for sustainable crop production. Soil samples were collected from the different zones of the study area and used to evaluate the soils texture, and physico- chemical properties. The results revealed that bulk density ranged from 1.3gcm-3 to 1.74gcm-3 with a mean value of 1.50gcm-1, while the hydraulic conductivity values ranged from 48.0 to 120.0 cm/hr with a mean value of 72.7cm/hr. The moisture content of the soils was as high as 47.72 to 59.11%. The soils were generally strongly acidic, ranging from pH 3.39 to 4.94. The organic matter status was generally low, ranging from 0.7 to 2.53 %. The Cation exchange capacity (CEC) was also generally low. The soils suffer multi-nutrient deficiencies. Total N was generally low in all the zones <0.15%, with a range of 0.042 to 0.14%. The available phosphorus in most of the soils were low (<15.0mg kg ), the exchangeable K had a range of 0.077 to 0.246 Cmol/kg. The exchangeable Ca had a range of 1.60 to 5.20 Cmol/kg, low to medium level, while Mg and Na had ranges of 0.80 to 3.20 Cmol/kg and 0.044 to 0.139 Cmol/kg respectively. It was concluded that the soils require conventional to minimum tillage, use of organic manures, judicious use of organic residues, liming, Bio-fertilizers and NPK fertilizers in other to sustain the soil for intensive crop production. Keywords: Soil fertility; Wetlands; Anambra river basin; Crop production