LAND SUITABILITY ASSESSMENT FOR RAINFED CASSAVA (Manihot esculenta Crantz) PRODUCTION IN FARM SETTLEMENT (PAPA ABEDE), OGBOMOSO, OYO STATE, NIGERIA

Reliable land suitability information strengthens site-specific management decisions for cassava (Manihot spp.), a crop of major economic and food-security importance in Nigeria, yet such site-level assessment has received little attention in the derived savanna zone around Ogbomoso. This study assessed the suitability of soils for rainfed cassava production in twelve soil observation points at Farm Settlement (Papa Abede), Ogbomoso, Oyo State, Nigeria. Surface soil samples were collected at a depth of 0-30 cm using the rigid grid method along transverses cut at 100 m intervals, and analysed for physical and chemical properties following standard laboratory procedures; soil morphology (profile depth and drainage) was additionally assessed from representative profile pits described using standard soil survey procedures. The soils were sandy loam in texture, with sand, silt and clay contents averaging 78.3%, 11.2% and 10.5% respectively. Soil pH (H2O) ranged from 5.04 to 6.12 (slightly to moderately acidic). Organic carbon (1.35-3.76%) and total nitrogen (0.18-0.49%) were generally low, while available phosphorus (0.08-14.76 mg/kg) and exchangeable potassium (0.04-0.21 cmol/kg) were also low at several soil observation points. A significant positive correlation was found between organic carbon and available phosphorus (r = 0.68, p = 0.015), suggesting organic matter management as a practical lever for improving both properties. Using the FAO parametric land-matching system with the square-root method for combining individual land quality ratings, climate, slope and pH were rated highly suitable (S1) with no limitation across all soil observation points, while total nitrogen, though generally low, is not part of the cassava-specific suitability criteria used here (Sys et al., 1993) and available phosphorus and exchangeable potassium showed very severe, permanent-class limitations (N2) at about half of the soil observation points; profile depth was found to be adequate (S1) at representative sampling points, while drainage was seasonally poor (S3) at these points. Overall suitability, by observation point, ranged from marginally suitable, S3dk (Lu2, Lu7, Lu9, Lu11, Lu12), through currently not suitable but correctable, N1dk/N1dp (Lu1, Lu6, Lu8, Lu10), to not suitable, N2pk (Lu3, Lu4, Lu5), driven mainly by drainage, phosphorus and potassium rather than nitrogen. The findings indicate that the soils of Papa Abede farm settlement are currently constrained mainly by nutrient status and drainage rather than physical land qualities overall, and can become suitable for cassava cultivation with targeted phosphorus and potassium management together with drainage improvement, guided by the site-specific variability identified in this study.