Spatial Variability of Soil Physico-Chemical Properties and its Influence on Irish Potato Production in Bokkos and Mangu Local Government Areas, Plateau State, Nigeria

Irish potato (Solanum tuberosum L.) production in Nigeria faces significant yield constraints despite favourable climatic conditions on the Jos Plateau. This study investigates the spatial variability of soil physico-chemical properties affecting Irish potato cultivation in Bokkos and Mangu Local Government Areas of Plateau State. Using geospatial techniques and inverse distance weighting (IDW) interpolation, 240 composite soil samples were collected from randomly selected potato farms at 0-30 cm depth across a 3,329.41 km2 study area. Key soil parameters analyzed included texture, pH, organic matter, total nitrogen, available phosphorus, and potassium. Results revealed predominantly sandy clay loam soils (75% in Mangu, 60% in Bokkos) with significant spatial heterogeneity in chemical properties. Soil pH ranged from 4.0-7.0, with 77% of soils classified as moderately to very strongly acidic (pH < 5.36), potentially limiting nutrient availability. Organic matter content was predominantly low to very low across 67.6% of the study area (0.2-1.19%), indicating poor soil fertility status. Total nitrogen levels were critically deficient, with 83.2% of soils showing very low to low concentrations (0.01-0.084%). Available phosphorus ranged from 3.68-23.24 mg/kg, with 55.6% of soils exhibiting very low to low levels. Potassium availability was more favourable, with 51.5% of soils showing moderate to very high concentrations (0.278-0.749 cmol/kg). The spatial analysis identified central areas of both LGAs, particularly around Kerang, Ampang, Kwatas, and Daffo, as having improved soil fertility status due to volcanic ash deposits and basaltic parent materials. These findings indicate that 45-55% of the study area possesses adequate soil conditions for potato production, while the other areas requires targeted soil amendment strategies including liming, organic matter incorporation, and balanced fertilization to optimize yields.