Suitability assessment of soils derived from fine-grained biotite gneiss and schist in rainforest region of southwestern Nigeria for pepper (Capsicum Sp. L.) production

Soils derived from fine-grained biotite gneiss and schist are extensive in southwestern Nigeria and are reportedly suitable for both arable and tree crops. Pepper is an indispensable part of the daily diet of millions of Nigerians. However, its productivity in southwestern Nigeria is low compared with its’ demand. This study assessed the suitability of soils formed in fine-grained biotite gneiss and schist in rainforest area of southwestern Nigeria for pepper production. The selected toposequence was delineated into four physiographic units and soil profile pits were established, described and sampled at each unit. The soil samples collected were analyzed for particle size distribution, pH, salinity and organic carbon. Land characteristics obtained were matched with the crop requirements for pepper to obtain the soils’ suitability classes using parametric method. Results show that the soils were currently marginally suitable (S3) to not suitable (N) for pepper production. The major agronomic constraints of the soils in order of severity were climate (too high rainfall), fertility (high soil acidity) and topography (slope greater than 3%). It was therefore recommended that planting in areas with less amount of rainfall (750-900 mm) and effective agronomic practices will ensure sustainable pepper production.