Assessing the impacts of shifting planting dates on crop yields and irrigation demand under warming scenarios in Alberta, Canada

Understanding the impacts of climate change on crop production and irrigation water demand is crucial for adapting to global warming. This study evaluated the effects of shifting planting dates on irrigated and rainfed crop yields and irrigation water demand under the latest Shared Socio-economic Pathways (SSPs) climate scenarios using the AquaCrop-OS model in Alberta, Canada. The results indicate: (1) climate change generally benefits irrigated crop yields while reducing rainfed yields under low mitigation scenarios (SSP585 and SSP370). (2) The impacts of planting date shifts on crop yields vary spatially and temporally across different SSPs. Early planting improves both rainfed and irrigated crop yields and reduces irrigation water demand under SSP585 in the latter half of the 21st Century, suggesting it is a viable strategy for mitigating heat and water stress in agricultural systems. However, this strategy does not guarantee yield increases under other SSPs. (3) The irrigated yields of spring wheat and canola are expected to increase under all scenarios, while rainfed yields decline under SSP585 and SSP370, with only marginal increases under SSP126. Annual irrigation demand will increase in the future, with the monthly irrigation peak occurring earlier. The most irrigation demand is under SSP585, followed by SSP370 and SSP126. (4) Early planting results in reduced irrigation water demand.