beta-Carotene rich orange-fleshed sweet potatoes are increasingly used in community-based interventions aimed at addressing vitamin A deficiency, but are often cultivated in marginal soils and with sub-optimal agricultural inputs. The aim of the study was to determine (i) beta-carotene content, beta-carotene yield and water productivity at increments of water application, and, (ii) beta-carotene content and beta-carotene yield at increments of chemical fertilizer application for orange-fleshed sweet potato in separate field trials. beta-Carotene content at the low irrigation treatment was between 15 and 34% higher than at optimal irrigation treatment. Increased water application brought about a two-fold increase in beta-carotene yield per unit area. The best combination of beta-carotene yield and water productivity (g beta-carotene ha -1 mm -1 water applied) was achieved at the intermediate (60%) irrigation treatment. Calculations showed that 1 ha of orange-fleshed sweet potato produced at the intermediate water application at yield level of 24.6-28.4 t ha -1, can potentially provide 452-730 households (of six persons) with an adequate amount of vitamin A over a period of 180 days. beta-Carotene content was 14% higher for both intermediate (50%) and high (100%) fertilizer treatments, compared to the 0% fertilizer treatment. beta-Carotene yield increased two-fold at the intermediate and four-fold at the high fertilization treatment. This paper provides novel information on the effect of irrigation on beta-carotene yield, as well as beta-carotene water productivity in orange-fleshed sweet potato. Follow-up research on a range of varieties is suggested toward obtaining recommendations for broad application in vitamin A crop-based interventions to optimize the beta-carotene yield in orange-fleshed sweet potato.
