Received: 22 August 2018 / Accepted: 09 September 2019/ Published online: 14 November 2019
The AquaCrop simulations show 5%–30% yield increases by 2050.
Irrigation access can increase yield by 17%, or from 60 t/ha to 71 t/ha, by 2050.
Shifting the planting dates from May to March can increase yield by 13%.
December to March rainfall explains 82% of variability in the simulated yields.
Guidelines for upscaling point models to larger areas show potential for Philippine application.
The Philippines is a major exporter of sugarcane, ranking 9th in global production. By 2024, the government aims to increase the country’s sugar productivity by 27% (from 60 t/ha to 75 t/ha) by consolidating rainfed farms and investing in irrigation. Although it is generally known that climate change affects crop production and food security, there is little understanding of how climate change and El Niño-Southern Oscillation (ENSO) events will impact production targets and future irrigation requirements. Crop models are cost-effective tools that can help policy makers and food planners to adapt to the changing weather and rising CO2 emissions; however, the methods used in crop modeling need to give robust, reproducible, and transparent estimates before they are used with confidence by food authorities. This study simulated the crop responses of sugar-growing farms in Negros Occidental, Philippines to ENSO events and mid-century climate using the AquaCrop model. The point model was extrapolated and converted into provincial scale to help agricultural planners in their decision making. The upscaled model was validated using yield data from 2005 to 2017. The climate change projections show that cane yield would increase from 5% to 30% by 2050 due to wetter summers. Rainfall from December to March explains 82% of the variability in the simulated annual yields, indicating higher irrigation returns. This study demonstrated the utility of crop models and upscaling methods, which can guide future climate change assessments at larger scales.