Design and optimization of a single-row potato harvester for smallholder farmers

Abstract

Mechanisation remains vital for increasing productivity and reducing labour demands in small-scale agriculture. In Kenya, many smallholder potato farmers still depend on inefficient manual harvesting methods, which raise labour costs, post-harvest losses, and lower farm profitability. This study details the design, construction, and optimisation of an affordable single-row potato harvester tailored for the agro-ecological and socio-economic conditions of smallholder farms. The prototype combines a digging blade, soil-sifting unit, and tuber collection system powered by a compact petrol engine to ensure affordability, simplicity, and ease of adaptation. Field trials were carried out in representative potato-growing regions with soils ranging from sandy to loamy, and from wet to dry. Performance was evaluated based on harvesting efficiency, tuber damage rate, labour input, and soil contamination. The harvester achieved a 70-75% reduction in labour time (4.5–5 hours/ha vs. 15–20 hours/ha manual) and demonstrated tuber damage rates below 1% in favorable conditions, substantially mitigating the typical >20% post-harvest losses associated with manual methods. These findings demonstrate that locally designed mechanisation can significantly improve harvesting efficiency and profitability for smallholder farmers. The study recommends increasing production, providing farmer training, and further optimising the harvester to enhance performance in challenging soil conditions. Overall, the work supports sustainable mechanisation practices that strengthen rural livelihoods and food security in regions where potatoes are grown.