Conventional to Agroecological Vegetable Production: Five-Year Evidence on Productivity, Profitability, Variability and Whitefly Management under Smallholder Conditions in Southwest Ethiopia

Abstract Smallholder vegetable production in Ethiopia often relies on synthetic inputs, while multi-year on-farm evidence on agroecological alternatives remains scarce. We evaluated a five-year (2021–2025) transition from conventional management (2021) to an agroecological package (2022–2025) on a multi-plot vegetable farm at the Eladale research site of Jimma University, southwest Ethiopia. From 2022 onward, synthetic fertilizers and insecticides were replaced with animal manure and garlic maceration, alongside crop diversification, rotation, and marigold companion planting in pepper and tomato plots. All eight crops showed significantly higher annual revenue under agroecological management than at baseline, whereas mean harvest increased in 30 of 32 comparisons (p < 0.0001). All crops profit margins increased, by up to about 18.5 percentage points. Since implied unit prices rose approximately three to five fold, these economic gains are nominal and partly price-driven. Monte Carlo simulation (1,000 iterations per crop) indicated wider revenue variability for pepper, carrot and garlic, than for beetroot and onion. Carrot had the highest fertilizer-use productivity (14.2 kg/kg), whereas garlic and pepper had the highest prices (170 and 85 ETB/kg). A composite stress index for conventional management was highest for tomato (0.62 units/kg) and pepper (0.37) and lowest for carrot (0.16). Whitefly was recorded in pepper and tomato in 2021, in 2022 only in tomato, and not in 2023–2025. The findings suggest association, rather than causation, as the agroecological practices were applied jointly without replication or untreated controls. The agroecological transition appears productive and viable, with crop selection weigh returns, risk and input efficiency.