Fertility status of selected soils developed on shale and sandstone parent materials in Odukpani Local Government Area, Cross River State, Nigeria

Abstract

The study evaluated the fertility status of soils developed on shale and sandstone parent materials in Odukpani LGA of Cross River State as a critical determinant of their proper management and utilization. Four pedons were sunk- two on each parent material and a total of sixteen soil samples were collected from different horizons of the profiles, processed and taken to the laboratory for analysis. Particle size analysis revealed that the texture of the soils of the two-parent materials varied from sandy clay, silty clay,sandy loam to sandy clay. The pH showed that soil of shale parent material was very strongly acidic with surface and subsurface means of 4.25 and 4.36 while that of sandstone was strongly acidic with mean values of 5.0in both top and subsoils. Except for pH, all other chemical properties were higher in shale parent material than in sandstone parent material. Organic carbon had surface and subsurface means of 2.82 g/kg and 0.91 g/kg, 1.71 g/kg and 0.37 g/kg, while total N had surface and subsurface, means 0.13 % and 0.08 %, 0.13 % and 0.03 % in soils of shale and sandstone parent materials respectively. Available P had surface and subsurface means of 19.7 mg/kg and 8.04mg/kg in shale parent material, 11.4 mg/kg and 7.44 mg/kg in sandstone parent materials. Exchangeable Al3+ was higher than H+ in both soils meaning that Al3+ was the primary cause of acidity. ECEC was low in both soils with surface and subsurface means of 10.72cmol/kg and 5.94cmol/kg in shale, 7.23 cmol/kg and 4.56 cmol/kg in sandstone while BS was high with mean values 84.04 % and 76.9 % in shale, 77.02 % and 72.07 % in sandstone representing surface and subsurface soils accordingly. The study revealed that soil developed on shale stone is more fertile than that of sandstone and as such more agronomic inputs and management practices will be required to enhance sustainable production in soils developed on sandstone than their shale stone counterpart.