Assessment of climate change impacts on sweet corn (Zea mays L.) production in the province of Laguna, Philippines using DSSAT Ceres-Maize model / Joie Durban Cataytay.

Dissertation (Doctor of Philosophy (Agricultural Engineering)) -- University of the Philippines Los Baños, December 2019.

CHED Funded Research.

INTRODUCTION -- REVIEW OF LITERATURE -- MATERIALS AND METHOD S-- RESULTS AND DISCUSSION -- SUMMARY AND CONCLUSION -- RECOMMENDATIONS -- LITERATURE CITED -- APPENDICES.

The study aimed to evaluate the climate change impacts on sweet corn production using the DSSAT CERES-Maize model. Field experiments were conducted to serve as the basis for calibrating and validating the model. The effect of irrigating near and above field capacity (PC) on sweet corn production was determined through field experiments laid in a randomized complete block design (RCBD) with four treatments replicated three times. Results showed that maximum crop yield can be obtained under the irrigation treatment with allowable depletion of 20% PC during the wet season and under irrigation up to saturation during the dry season at 1 1 tons/ha and 13 tons/ha, respectively. The model performed well during calibration and validation with R^2 of 0.78 to 0.99, RMSE of 348.2 kg/ha to 1,023.8 kg/ha, 515 to 1,140 kg/ha and 0.27 to 0.39 for yield, biomass and leaf area index (LAI), respectively. Computed d-stat ranged from 0.94 to 0.99, RMSEn of 6.79 % to 15.61%, and NSE of 0.75 to 0.95. Model simulations were performed to predict the impact of climate change on sweet corn production based on Climate Information Risk Analysis Matrix (CLIRAM) tool for climate change projections. Results showed that sweet corn production is viable for future climate change scenarios under rainfed conditions with proper timing of planting date. The optimum planting window under rainfed condition is within the third week of January and the second week of May for the dry and wet season, respectively. Recommended planting dates for irrigated growing are on January 1 1, March 28, June 27 and October 26 for optimum yield. Also, the provision of drip irrigation proved to be economically feasible with a benefit-cost ratio of 4.37 to 5.09. Net economic benefits for irrigated production are higher by about 69% to 79% in RCP 4.5 and 59% to 69% in RCP 8.5 scenarios compared to rainfed. Irrigated corn production can generate an additional profit of more than 59% relative to rainfed production. The results of this study can be used as the basis for maximizing the potential benefits of corn production in the province of Laguna in view of climate change.