ASSESSMENT OF SOIL CHEMICAL DEGRADATION UNDER KOLANUT PRODUCTION IN IMOTA LAGOS STATE

ABSTRACT

One of the most serious problems currently affecting agricultural production in developing countries especially Nigeria is land degradation. The adverse effect of land degradation on soil production, soil health and food security is an important current global issue. Hence, this study assessed the chemical degradation of soils under kolanut production with the view of optimizing its production through appropriate management practices that is environmentally friendly and sustainable. Surface (0-15 cm) and sub-surface (15-30 cm) soil samples were taken at an equidistant point of 100 m interval across ten hectares of land using grid survey method. The collected samples were subjected to chemical analysis following standard procedures. The extent of soil degradation was assessed using direct approach of FAO (1979). The results showed that all the soils were highly degraded with respect to base saturation. About 52.5% of the soils were none to slightly degraded, 27.5% moderately degraded, 12.5% highly degraded and 7.5% very highly degraded with respect to nitrogen. In terms of potassium, 90% of the soils were none to slightly degraded, 2.5% moderately degraded, 5% highly degraded and 2.5% very highly degraded. In the case of phosphorus, 62.5% of the soils were none to slightly degraded, 27.5% moderately degraded and 10% highly degraded. Only about 25% were none to slightly degraded and the remaining 75% were moderately degraded with respect to exchangeable sodium percentage (ESP). The study concluded that prevention and remediation of soil degradation can be mitigated by stabilizing soil aggregates, improving soil structure, enhancing air and water exchange capacities, increasing nutrient cycling, and promoting greater soil biological activity.