Assessment and mapping of climate change impacts on spring wheat yield in Southern Saskatchewan using DSSAT and high-resolution RCM projections

Climate change presents both potential benefits and drawbacks for crop production in Canada. An assessment and mapping of future climate change impacts on spring wheat yield in Saskatchewan is crucial because the province largely accounts for Canada's share of the global wheat market. We applied ten climate change scenarios (high-resolution (0.22°) regional simulations) to the CERES-Wheat module of the Decision Support System for Agro-technology Transfer (DSSAT) model using a historical baseline period (1975-2004) and three 30-year future periods: near (2010-2039), middle (2040-2069), and far (2070-2099). The model showed high accuracy with d-values always higher than 0.75 for the calibration (d-value = 0.84) and the validation (d-value = 0.82) periods. Furthermore, the model showed a remarkable similarity between the observed and simulated spring wheat yields. Results indicate a median yield increase of 16.1% in the near future, 27.5% in the middle future, and 10.9% in the far future. While there is a general rise in the annual wheat yield under future climate conditions and elevated CO₂, yield in the far future exhibits a notable decline, particularly in the extreme southern and southwestern areas of Saskatchewan which is exposed to increased aridity under higher temperatures. Conversely, the northern regions are expected to experience significantly higher yields, primarily due to a shift towards wetter conditions and longer growing season. Whereas DSSAT is a commonly used model, the current research is novel by extending the analysis at high-resolution over a large area representing more than 40% of Canada's crop land.