Impact of biochar and inorganic fertilizers rates on yield and yield components of maize at Bako western Ethiopia

Soil acidity is a major constraint to maize production in western Ethiopia, where maize is used as a major staple crop. This problem severely limits yield, threatening food security and farmers’ livelihoods. To manage soil acidity and enhance maize productivity, this study was initiated to evaluate the effect of combined application of biochar and inorganic fertilizers. A two-year field experiment (2023/24 and 2024/25) was conducted at Bako, western Ethiopia, using a randomized complete block design (RCBD) arranged in a factorial with three replications. Treatments included three rates of biochar (0, 5, and 10 t ha−1), nitrogen (0, 46, and 92 kgha−1), and phosphorus (0, 34.5, and 69 kgha−1 P2O5). Major agronomic parameters were measured to assess treatment effects. The results showed that combined application of biochar and inorganic fertilizers significantly increased maize leaf area index (P > 0.01) and grain yield, and significantly (P > 0.05) increased biomass, grain number, and grain weight. The highest grain yield obtained with 5 or 10 t ha−1 biochar combined with 92 kgha−1 N and 69 kgha−1 P2O5. Economically, 5 t ha−1 biochar with the same N and P rates was optimal for acid-prone soils. This treatment increased grain yield by 24.1 % over recommended inorganic fertilizer alone and improved biomass, grain number per ear, and grain weight by 33.9 %, 23.2 %, and 12.2 %, respectively. The combined application reduced soil acidity, improved soil properties, and enhanced maize productivity. As the study covered only two seasons, long-term experiments are required to verify the persistent effects of biochar.