Is mechanized conservation agriculture a promising solution for smallholder farmers? Evaluating its short-term agronomic and economic performance in Ethiopia

Mechanization can play a key role in addressing farm power limitations and driving an agricultural transformation in Sub Saharan Africa (SSA), but conventional mechanized tillage can lead to land degradation. Mechanized conservation agriculture (CA) could help to address this concern, but little is known about its agronomic and economic performance in SSA. We explore mechanized CA performance in two contrasting agro-ecological conditions in Ethiopia – specifically a maize-haricot bean system in sandy loam soils in semi-arid Melkassa, and a wheat-faba bean system with heavy clay soils in sub-humid Kulumsa. We employed a Randomized Complete Block Design experiment with three treatments and three replications; (1) conventional disc and harrow tillage (CT), (2) reduced tillage – ripper (RIPT), (3) no-tillage– no-till seeder (NT). The results indicated that in Melkassa, where improved soil moisture availability was attained, RIPT enabled significantly (p < 0.05) higher maize yields (2595 kg ha⁻¹ and 5831 kg ha⁻¹, in 2022 and 2023 respectively) compared to CT (1751 kg ha⁻¹ and 3246 kg ha⁻¹) and higher gross margins (825 US$ ha⁻¹ and 2624 US$ ha⁻¹) obtained for maize compared to CT (261 US$ ha⁻¹ and 1126 US$ ha⁻¹). In Kulumsa, no significant yield difference was obtained between CT and CA (RIPT and NT) treatments for wheat in both seasons, however, wheat was the most profitable crop under RIPT due to a 13 % reduction in total variable cost. The promotion of rippers appears to be a useful first step to replace conventional tillage with mechanized CA practices in Ethiopia, potentially using rental services.