Analysis of the Potato Production Under Climate Change through Crop Modeling.

Potato is the most important non-grain crop worldwide and the impact of climate change on potato production will be critical for global food security. Crop models can be robust means to assess the impacts of climate change and potential adaptations if models are well tested and proven to reproduce field-based experiments. Many models have been used in climate change impact assessments, but they often lack comprehensive field-testing. SUBSTOR-potato model is widely used to assess the impact of climate change on potato crop; nevertheless, the model lacks of field-testing for high levels of atmospheric CO₂ and heat stress conditions. In this study, we analyzed the performance of the SUBSTOR-potato with field experiments across the world including treatments under high temperature environments and elevated atmospheric CO₂ concentrations. The SUBSTOR-potato model simulated well tuber growth and yields over a wide range of current growing conditions and crop management practices across many geographic regions. However, the model response under elevated atmospheric CO₂ and high temperature environments were poorly simulated. Model routines were improved and implemented to capture the impact of high temperatures and high levels of atmospheric CO₂ on crop development. When using the improved model across 0.5x0.5 degree grid cells over all potato growing regions in the world, the simulated aggregated country tuber dry yields reproduced nationally-reported potato yields with a RRMSE of 56%. Applying future climate change scenarios to current potato cropping systems indicated small global tuber yield reductions by 2055 (-2 to -6 %), but larger declines by 2085 (-2 to -26%), depending on the Representative Climate Pathway (RCP). Uncertainty due to different climate models became larger than year-to-year variability by the end of the century. Therefore, adapting potato cultivars and cropping systems to climate change needs be explored to ensure future food security, particularly in high population growth regions.