Recently, corn farmers in Abuan Watershed and Isabela Province are experiencing declining crop yields caused by an insufficient amount of rainfall. To increase crop yields and reduce production risks, research on better use of available rainfall and a better understanding of the effects of climate variability, and soil and field management on crop production is imperative. Simulation models, driven by daily climatic data, can be used to predict the impact of long-term climate variability on the probability of success of a range of crops, and water and soil management strategies. Calibration of the model was based on field data from Cagayan Valley Research Center at Ilagan, Isabela during two growing seasons in 2013-2015. Model validation of phenology, yield, and biomass was undertaken on-station and at farmer fields. Results showed acceptable accuracy between actual and simulated data. Specifically, the model yields high efficiency of 0.86 in predicting the yield of participating farmers. It also demonstrated the possibility of simulating the production of other hybrid varieties. Projected yield as affected by temperature and rainfall changes indicated a sharp reduction by up to 44% in 2020 and 35% in 2050. The model can be used as an important input in developing a decision support system by the Department of Agriculture and local government units.
