Integrated nano-granular fertilization enhances soil–plant functional plasticity and maize productivity under conventional tillage

Abstract Nutrient depletion and low fertilizer use efficiency remain major constraints to sustainable maize production in sub-Saharan Africa. Although conventional NPK fertilizers are widely used, their high cost, bulkiness, and susceptibility to nutrient losses limit productivity and profitability among smallholder farmers. Nano-fertilizers have recently emerged as promising alternatives due to their enhanced nutrient delivery efficiency and reduced environmental losses. This field study evaluated the effects of conventional NPK, Nano fertilizers in the form of nano diammonium phosphate (Nano-DAP) and nano urea, and their combinations on soil nutrient dynamics, maize productivity, and economic returns under conventional tillage system in Ghana. Five treatments comprising: control (T1), recommended NPK (T2), single nano application (T3), split nano application (T4), and integrated NPK + nano fertilization (T5) were arranged in a randomized complete block design with three replications. Integrated fertilization (T5) consistently enhanced mineral nitrogen availability, particularly nitrate-N, while maintaining favorable soil chemical conditions. Plant height increased by 36.5%, 30.7%, 30.3%, and 29.9% under T5, T2, T4, and T3, respectively, relative to the control. Similarly, T5 produced the greatest leaf number, cob length, grain number, and grain yield in both seasons. Economic analysis showed contrasting optimisation patterns, with T5 generating highest net returns, whereas split nano application (T4) achieved the greatest benefit-cost ratio (2.86), reflecting superior input-use efficiency. Overall, integrating conventional NPK and nano-fertilizers improved nutrient synchrony, enhanced maize productivity, and increased farmer profitability, while split nano-fertilization (T4) provided a cost-efficient alternative for resource-constrained farming systems. We therefore recommended T4 as a climate smart and cost effective fertilizer alternative for resource-constrained farmers in Ghana.