Parameterizing the FAO AquaCrop Model for Rainfed and Irrigated Field-Grown Sweet Potato

Crop production in the Caribbean is dominated by small open field holdings that are almost totally reliant on rainfall. Sweet potato (Ipomoea batatas L. Lam. [Convolvulaceae]) has been identified as an important commodity to attain food and nutrition security goals of the region, particularly in light of a changing climate. The crop has high nutritional value, innate drought-tolerant properties, and can be grown with relatively low inputs. The routine use of crop models for yield optimization is largely absent in the Caribbean. In this study, an attempt was made to parameterize the FAO AquaCrop model for sweet potato for the first time. AquaCrop is a simulation model for crop water productivity, designed primarily for use in irrigation management. Parameters were developed using data from three sweet potato cultivars grown in two agroecological zones in Jamaica under rainfed and irrigated conditions. Digital photography was combined with an automated canopy estimator to track canopy development, and sample harvesting was done throughout the crop season. The overall simulation of biomass was good, with deviations of <28% for four out of six simulations, and season-long performance of the model was commendable. The simulation of yield presented more challenges, especially given the nonlinear rate of tuber development. The results, however, indicate that AquaCrop could be a useful tool for Caribbean agriculture in predicting the productivity of sweet potato under varying water availability.