FORMS OF SOME MICRONUTRIENTS IN COASTAL PLAIN SAND PARENT MATERIAL IN IKPOBA-OKHA LOCAL GOVERNMENT AREA OF EDO STATE

ABSTRACT

The study was carried out to determine the forms of micronutrients in coastal plain sand parent materials in Ikpoba Okha local government area of Edo state, Nigeria. Locations used were Ohonsa, WAEC road, Iyanomon and Ukihri areas. Soil auger was used in making boring points at soil depths of 0-15cm, 15-30cm, 30-45cm, and 45-60cm. Forms of micronutrients studied include water soluble, exchangeable, residual, carbonated, organically bound forms of micronutrients. Results from the experiment show that pH of soils in the studied areas ranges between 5.7-6.6  and 5.4-5.4(acidic). Organic carbon content across the lower soil depth was less than 20, but soil depth of 0-15cm had above 20g/kg organic carbon. Exchangeable bases decreased across soil depth (0.79-0.74, 0.39-0.31,0.39-0.21, 0.25-0.13) probably due to leaching of basic nutrients. Residual forms of copper, zinc and manganese had the highest values across all locations and soil depths, (15.29-15.18) (14.03-19.43).Water soluble forms had significant difference across all locations of the studied areas (0.57-0.49) (0.35-0.29). In terms of increased contents in the coastal plain sand parent materials, it follows this order: Total >  residual > carbonate> organically bound> exchangeable> adsorbed> water soluble forms of micronutrients.