Fertility Evaluation of Some Soils in Adamawa State, Nigeria

Surface (0-25) and sub-surface (25-80) soil samples were collected from Hong, in Hong Local Government and Chouchi plains, Yola South Local Government with the aim of evaluating their fertility status. The soils were evaluated both in the field and laboratory. Results of the analyses showed that sandy loam soils dominated the upper layers, sandy clay loam to clay loam in the lower horizons in Hong while silt loam dominated the soils of Chouchi both in upper and lower horizons. Soil reaction ranged from slightly acidic to alkaline in both sites (7.5-9.5). Organic carbon content does not have a definite trend in the horizons of Hong soils but higher at the lower horizons in Chouchi plains. Total nitrogen (TN) was generally moderately low to medium while available phosphorus (AVP) ranged from low to medium. Exchangeable bases were generally low except sodium content that was very high in Hong soils. The effective cation exchange capacity (ECEC) and percent base saturation (PBS) of the soils ranged from low to medium. SAR values were generally low in both sites although comparatively higher in Hong soils. Except for total nitrogen (TN) and ESP, the coefficient of variability within the profiles of Chouchi soils were not significant while significant variability was observed in relation to EC, TN and AVP in Hong soils. Organic carbon negatively and significantly correlated with total nitrogen (TN), available phosphorus (AVP), percent base saturation (PBS) and exchangeable sodium percentage (ESP). A highly significant correlation was however observed between TN, AVP, ESP and PBS. This suggests that sustainable productivity of the soils requires careful management of nitrogen fertilizers and salts in Chouchi. Nitrogen, phosphorus and salts need to be monitored and properly managed if the productivity of Hong soils is to be sustained.