Soil Characteristics Around Lake Opi In Eastern Nigeria And Land Use Recommendations

Abstract

In most developing countries including Nigeria basic data on soils and landscape features for proper land use planning are often lacking or scanty. In this study, variations in the properties of soils as well as landscape features around Lake Opi in eastern Nigeria were assessed. The objectives were to characterize the soils, ascertain any effects of the lake on the soils and make recommendations for the sustainable use of the soils and the lake itself. The soils around the lake (@500-m radius) were sampled at 10-m intervals at approximately three concentric transects around the lake for preliminary information on consistence, texture and colour using auger samples. Based on the information obtained, 5 representative profiles were dug, 3 at @7 m from the lake and 2 at @ 200 m from the lake. The profiles were fully described and samples were collected from the pedogenic horizons for the determination of the relative proportions of particle sizes, pH, soil organic matter (SOM), total N, exchangeable bases and acidity, cation exchange capacity and available P. Comparatively the major differences in the soils that were attributed to the influence of the lake were the thickness of Ap, E/AB, and Bt/BC horizons as well as the contents of clay, SOM, available P, total exchangeable bases and effective cation exchange capacity in these horizons. All, except the thickness of Ap horizon, were relatively higher in the soils 200 m from the lake than in soils proximate to the lakeshore when comparing the mean values obtained from the Ap horizons. Thus, based on the fertility indices in the A horizon, the soils 200 m from the lake were more fertile than those closer to the lake. Again the soils 200 m from the lake appeared to be less variable (lower coefficients of variation) in soil physicochemical properties than those closer to the lake. Thus, the soils 200 m from the lake were generally more developed and were classified as Haplustalfs (Lixisols) using the Soil Taxonomy and FAO/UNESCO systems. Those proximate to the lake were classified as Haplustept (Alisol) and Ustorthent/Ustifluvent (Fluvisols). Based on the soil characteristics and landscape features, an integrated agricultural production system involving vegetable, poultry and fish farming were recommended for the area.


Agro-Science Vol.2(1) 2001: 76-89