Impacts of climate variability and multiple fertilization strategies on rainfed maize production in Sub-Saharan Africa

Maize (Zea mays L.) production in Sub-Saharan Africa (SSA) is highly sensitive to climatic variability and declining soil fertility. This study used the DSSAT-CERES-Maize model to simulate the impact of climate variability (1984–2023) on rainfed maize performance under four fertilization treatments (control, organic, inorganic, and combination) across five representative sites: Béréba (BF; Burkina Faso), Nabdam (GH; Ghana), Bumula (KE; Kenya), Bombali (SL; Sierra Leone), and Monduli (TZ; Tanzania). Temperature increase consistently accelerates maize development. For each 1 °C rise in seasonal mean temperature, time to anthesis and maturity shortened by 3–7% and 3.7–6.4%, respectively, with the strongest responses observed in Bumula (KE) and Bombali (SL). These phenological shifts indicated shorter growing cycles under warming conditions. Yield responses to fertilization varied markedly across sites. Significant yield gains were achieved only in Bumula (KE) and Nabdam (GH), primarily under inorganic and combined fertilization treatments. No yield improvements were recorded in Béréba (BF), Bombali (SL), or Monduli (TZ), showing that fertilizer effectiveness depended on local rainfall and soil conditions. Rainfall was a major driver of yield variability. In Nabdam (GH) and Bombali (SL), excessive rainfall correlated negatively with yields, while in Bumula (KE), both rainfall and fertilization significantly affected outcomes. Inorganic fertilizer produced the highest and most stable yields across rainfall gradients, while integrated nutrient management moderately buffered yield losses compared to organic or unfertilized systems. These findings highlight the importance of site-specific nutrient and climate adaptation strategies to enhance maize productivity and resilience across diverse agroecological zones in SSA.