Gross margin comparison between different growth media for potato minituber production

Potato (Solanum tuberosum L.) is the second most consumed food crop in Kenya. Due to numerous production challenges, its yield remains low at 8.6 tonnes/ha compared to global productivity of 40-45 tonnes/ha. This gap in productivity is associated with the use of uncertified seeds or minitubers, unsuitable growth media for minituber production, rapid decline in soil fertility, pest and diseases amongst others. The use of unsuitable growth medium affects the quality and quantity of the minitubers and consequently potato production. An experiment was therefore set up to evaluate the effects of different growth media namely untreated cocopeat, treated cocopeat, and soil for the production of certified potato minitubers. A pot experiment arranged in a randomized complete block design (CRD) with three replicates was conducted at the Climate and Water Smart Agriculture Centre of Egerton University, Kenya. Data were collected on tuber yield, number of tubers, and cost of inputs used per treatment and analyzed for the productivity, percentage gross profit margin, and an operating expense ratio. The results showed that the highest yield (20.67 tonnes/ha), number of tubers (22 per plant), and percentage gross profit of 75.01% were obtained in the treated cocopeat (T2). The untreated cocopeat had the second highest yield, number of minitubers, and percentage gross profit of 46.42% followed by the soil treatment (T3) with a percent gross profit of 8.82%. The results suggest that for minituber production under greenhouse condition, the use of treated cocopeat was 28.59% and 66.19% more profitable as compared to the untreated cocopeat and soil, respectively. Therefore, treated cocopeat should be used for the production of potato minitubers because of its high productivity and profitability. Key words: Cocopeat, gross profit margin, minituber, potato