Soils of the Degraded Derived Savanna Land in Southwest Nigeria: Distribution, Morphology and Sustainable Climate–smart Land Use Plan

Southwest Nigeria belongs to the humid tropical climate with a Wet/Dry Forest and a Derived savanna. The studied site is under the latter ecosystem (located around Ilero, 08.05N/03.22E in Kajola Local Government Area of Oyo State) and was a former mechanized farm with low-intensity land use pattern with seasonal uncontrolled burning/grazing with a subsequently degraded landscape. And to encourage the habits of sustainable land-use management, the objectives of this study were: [1] to produce a detailed soil map of an approximate 1,293ha [12.93 sq. km] land mass at the soil series level and [2] to use the soil/landform properties to formulate a land use plan suitable for a sustainable climate-smart watershed management plan. The degraded landscape is characterized by: induced drainage channels at upper physiographic positions and equally devoid of vegetation attributed to cattle grazing, surface gravels/stones/cobbles typical at the middle slope positions, iron coated surface soils on the seepage areas, and common, massive exposure of iron pans on upper slope positions. Ten mapping units identified at Soil Series level [and classified into Soil Taxonomy/World Reference Base] include Shabe (2.6%), Ogboro (9.3%), Iwaji (2.2%), Amodu (1.9%), Tede (2.7%), Iwo (18.1%), Dejo (7.0%), Gambari ( 9.6%), Shante/ Apomu soil complex ( 34.3%) and Adio soil (12.3%). Potential common limiting factors for sustainable land use/management are soil erosion, effective soil depth, stoniness, and wetness/drainage. Mixed cropping and agro-forestry are suggested viable land use options for sustainable land use/management that are a conditional factor for climate-smart agriculture and sustainable ecosystem services.