Augmenting sustainable potato growth and mineral uptake under integrated organic and inorganic soil amendments

Potato (Solanum tuberosum L.) productivity in highlands dominated by acidic soils is frequently repressed by nutrient imbalance and poor canopy development. This study assessed the effects of sole and integrated organic–inorganic nutrient amendments on canopy growth, tissue nutrient uptake, and tuber yield in acidic Nitisols of Nakuru County, Kenya, over two successive cropping seasons (short rains of 2024 and long rains of 2025). Nine treatments, including mineral fertilizers (NPK, DAP), farmyard manure (OM), lime, and their combinations, were arranged (in triplicate) in a randomized complete block design. Integrated treatments significantly enhanced vegetative growth, physiological traits, and yield compared with the control and sole inputs (p < 0.001). Across seasons, OM + NPK produced the highest leaf area index (4.76), chlorophyll content (50.20 SPAD), and tuber yield (59.40 t ha−1), followed by OM + DAP (48.88 t ha−1), whereas the control recorded 0.72 t ha−1. Potassium uptake showed a positive association with canopy development (r = 0.52 with LAI), while micronutrient concentrations (Fe, Cu, Mn) were negatively associated with growth parameters, likely reflecting dilution effects under high biomass production. The results demonstrate that integrating organic and mineral nutrient sources improves canopy development and yield under acidic soil conditions. Because total nutrient inputs differed among treatments, comparisons reflect field-rate integrated management performance rather than nutrient-equivalent dose responses. Integrated nutrient management offers a practical strategy for enhancing potato productivity in smallholder systems on acidic Nitisols.