14. Classification, Characterization, and Suitability Evaluation of the Savanna Soils of Oyo North of Nigeria

A detailed soil survey of about 100 ha of Savanna ecoclimatic region of Oyo North of Nigeria was carried out to characterize and classify the soils and to assess the potential of the area for agricultural suitability. During this study, five soil mapping units were identified and delineated. Selected physical and chemical characteristics were determined to support soil taxonomy, FAO–UNESCO legend, and land fertility capability classification. Five soil pedons were classified according to USDA soil taxonomy as Arenic Kandiudults, Arenic Kanhapludults, Typic Kandiudults, Arenic Kandiudalfs, and Gross Arenic Kandiudalfs and according to FAO–UNESCO system as Ferric Lixisols, Stagnic Lixisols, and Haplic Lixisols, respectively. The studied pedons are assessed for fertility capability classification (FCC), and their FCC (Buol classification) is recognized as sandy topsoil (S), low CEC (e), and K deficient (k) and presented as pedon 1 and 2 as Sek (>35% gravels), pedon 3 as Sek (2–4% slope and >35% gravels), pedon 4 as Sek (4–7% slope and >35% gravels), and pedon 5 as Lek (>7% slope and >35% gravels). Sand-sized particles dominate in the entire profiles. The exchangeable bases are generally low, and the exchange sites are dominated by calcium. Total N and organic matter contents are also low. The soils are marginally suitable for commonly grown crops such as cassava, maize, and oil palm. Limitations to agricultural production include soil fertility (CEC), organic matter, poor texture, and climate (rainfall and length of dry season).