Characterization and classification of soils in Okitipupa Local Government Area, Ondo State, Nigeria.

摘要

A semi-detailed soil survey of the Okitipupa Local Government Area in Ondo State, Nigeria was carried out with the aid of Landsat-ETM satellite imagery at a scale of 1:50,000. Three soil mapping units designated as Okitipupa series, Omotosho series and Ode Erinje Fadama series were delineated and presented in a soil map. Okitipupa series occupies 41,623 ha or 52%, the Omotosho series covers 17,318 ha or 21.64% and the Ode Erinje Fadama series occupies 21,099 ha or 26.38% of the Local Government Area. All the soils have extremely to very strongly acid reaction and are nutrient impoverished. The soils also have rather sandy surface textures with sandy loam to sandy clay subsoils and are susceptible to severe surficial erosion hazard. In relative terms, the Okitipupa soil series which occur on nearly level landforms and are very deep may be considered as the prime agricultural lands, while the Omotosho series are marginal lands because they occur on strongly undulating landforms, are gravelly and shallow to bedrock or plinthic materials. The Ode Erinje Fadama series are seasonally flooded and are considered suitable for dry season vegetable farming and swamp rice production. According to the criteria of the USDA Soil Taxonomy System, the Okitipupa series is classified as Typic Paleudults, Omotosho series as Typic Plinthohumults and Ode Erinje Fadama series as Humaquentic Endoaquents at the subgroup level. These classifications correlate closely as Dystric Acrisols, Orthi-plinthic Acrisols and Arenic Gleysols for Okitipupa, Omotosho and Ode Erinje Fadama series respectively under FAO World Reference Base for Soil Resources.