DIRECTION: a Model-aided Irrigation Tool for Cassava Plantation

Cassava farming in Southeast Asia, including Thailand, the major cassava producer in the world market, will soon face severe water shortages as a result of the worsening global warming crisis. The recent loss of cassava production from the worst drought circumstances has highlighted the need for more effective water management, which allows farmers to optimize crop yield production with water use efficiency. Here, DIRECTION model was developed as a model-based decision support tool for cassava field irrigation. The model was simply developed by combining (i) the water balance model, which takes into account air weather data and soil moisture conditions, and (ii) the crop growth model, which simulates the growth response of cassava crop plants to the exposed water condition. The DIRECTION model gives information that is necessary for managing irrigation, including the amount of water required by plants at a certain moment and the estimated final yield on the day of harvest. The model was calibrated using Kasetsart 50 (KU50) and Rayong 9 (R9) cassava cultivars, in the provinces of Burirum and Khon Kaen in northeastern Thailand. Finally, the model was deployed to a cassava farmer, and the approach could increase cassava root production by twice with comparatively less water usage than usual practice. The DIRECTION approach is currently being applied to the cassava field in Vietnam, which is the first step in the pathway towards the regional impact of cassava production in Southeast Asia.