Biochar-based amendments reduce yield variability and enhance economic benefits in maize and cotton under smallholder farming in northern Benin

Abstract

In sub-Saharan Africa, maize and cotton are essential for food security and economic development, yet their productivity remains constrained by poor soil fertility and climate variability. This study assessed the effects of biochar-based amendments on yield variability, stability, and profitability of maize and cotton under smallholder farming conditions in northern Benin. Demonstration trials were conducted in 2020 and 2021 in two agroecological zones (Ina Gando and Padé) using a randomized block design consisting of seven treatments: control; biochar (234 kg ha −1 for maize and 271 kg ha −1 for cotton); compost (1,325.5 kg ha −1 for maize and 1,536 kg ha −1 for cotton); recommended mineral fertilizer (150 kg ha −1 NPK + 50 kg ha −1 urea for maize and 200 kg ha −1 NPK + 50 kg ha −1 urea for cotton); biochar + fertilizer (BF); biochar + compost (BC); and biochar + compost + fertilizer (BCF). Biochar-based treatments significantly increased maize grain yield by 95.5–227.0% and seed cotton yield by 109–190% compared with the control. Higher maize straw yield and 1,000-grain weight were observed in Ina Gando during the wetter year (1,505 mm rainfall) compared with Padé during the drier year (950 mm rainfall). Economic analysis showed that fertilizer (F) and BF treatments generated the highest net profit and benefit-cost ratio. Biochar-based treatments also exhibited lower yield variability (CV < 10%) and greater yield stability. Overall, integrating biochar with mineral fertilizer or compost appears to be a promising strategy for improving productivity, profitability, and resilience in the Sudano-Savanna region of West Africa.