Biochar Effects on Soil Properties and Yield of Maize in Northern Region, Ghana

Soil degradation and declining crop productivity are persistent challenges in global agriculture, particularly in sub-Saharan Africa. While biochar application has gained recognition as a sustainable soil amendment, this study systematically evaluates the effects of different biochar feedstocks and application rates on soil fertility and maize productivity in Ghana. Three agricultural waste materials (rice husk, groundnut husk and sawdust) produced as biochar were evaluated under 5 application rates for improved grain yield, yield components and soil characteristics during the 2022 and 2023 cropping seasons under field experimental conditions. The treatment consisted of 2 factors: three biochar and five levels of biochar application rates (0, 2, 4, 6, and 8 t ha-1). Soil chemical properties, including pH, organic matter, and nutrient availability, were analysed alongside maize yield parameters. The study demonstrates that groundnut husk biochar is the most effective at enhancing soil fertility and boosting maize yields, with the highest application rate (8 t ha⁻¹) leading to remarkable grain yield increases—up to 218.2% in 2022 and 106.3% in 2023. Soil organic matter content increased significantly, ranging from 89.6–343.4%, while nitrogen availability peaked at 220% in 2022 and 70% in 2023. Maize yield showed a strong positive correlation with soil fertility parameters, except for the harvest index. These findings provide critical insights into optimising biochar use for sustainable maize production in similar conditions worldwide, demonstrating its potential to enhance soil health and long-term agricultural productivity.