Productivity, Technical Efficiency, and Sustainability of Mechanized Potato Production: A Case Study of Tillage Service Users in Kenya

Abstract Potato ( Solanum tuberosum ) has a considerable potential to contribute to income generation and food security for smallholder farmers in Africa, but sustainable farming practices are required to exploit this potential. Kenya is an interesting example, as it is a leading potato producer in sub-Saharan Africa, but productivity has been declining in recent years. While past studies on potential reasons have focused on the use of seed, fertilizer, and pesticide use, mechanized land preparation has received limited attention, even though mechanization plays an increasing role in potato farming. To address this knowledge gap, we analyzed data from 156 smallholder farmers in Nakuru County, Kenya, who use mechanized tillage services for potato production. To determine their technical efficiency, we applied a stochastic frontier trans-log production function. The technical efficiency scores ranged from widely 11% to 93%, with a mean value of 63, suggesting that there is ample potential to raise potato production without bringing new land into cultivation. The use of pesticides and use of labor had a significant positive effect on the potato output. Unexpectedly, a negative response of potato output to fertilizer was found. The reason is likely that only farmers who already experienced soil fertility problems started to use fertilizer and that they applied inadequate amounts. The study also revealed other problems that affect soil fertility and yields, especially a lack of practicing crop rotation. Farm-specific advice by private extension providers was found to be more effective in improving technical efficiency than generalized training.