Non-stationary response of rain-fed spring wheat yield to future climate change in northern latitudes

Pouya Khalili; Badrul Masud; Budong Qian; Symon Mezbahuddin; Miles Dyck; Monireh Faramarzi

doi:10.1016/j.scitotenv.2021.145474

Non-stationary response of rain-fed spring wheat yield to future climate change in northern latitudes

Sci Total Environ. 2021 Jun 10:772:145474. doi: 10.1016/j.scitotenv.2021.145474. Epub 2021 Jan 30.

Authors

Pouya Khalili¹, Badrul Masud¹, Budong Qian², Symon Mezbahuddin³, Miles Dyck⁴, Monireh Faramarzi⁵

Affiliations

¹ Watershed Science and Modeling Laboratory, Department of Earth and Atmospheric Sciences, Faculty of Science, University of Alberta, Edmonton, AB T6G 2R3, Canada.
² Ottawa Research and Development Centre, Agriculture and Agri-Food Canada, Ottawa, ON K1A 0C6, Canada.
³ Natural Resource Management Branch, Alberta Agriculture and Forestry, Edmonton, AB, Canada; Department of Renewable Resources, Faculty of Agricultural Life and Environmental Sciences, University of Alberta, Edmonton, AB T6G 2R3, Canada.
⁴ Department of Renewable Resources, Faculty of Agricultural Life and Environmental Sciences, University of Alberta, Edmonton, AB T6G 2R3, Canada.
⁵ Watershed Science and Modeling Laboratory, Department of Earth and Atmospheric Sciences, Faculty of Science, University of Alberta, Edmonton, AB T6G 2R3, Canada. Electronic address: faramarz@ualberta.ca.

PMID: 33770871
DOI: 10.1016/j.scitotenv.2021.145474

Abstract

The non-stationary response of crop growth to changes in hydro-climatic variables makes yield projection uncertain and the design and implementation of adaptation strategies debatable. This study simulated the time-varying behavior of the underlying cause-and-effect mechanisms affecting spring wheat yield (SWY) under various climate change and nitrogen (N) application scenarios in the Red Deer River basin in agricultural lands of the western Canadian Prairies. A calibrated and validated Soil and Water Assessment Tool and Analysis of Variance decomposition methods were utilized to assess the contribution of crop growth parameters, Global Climate Models, Representative Concentration Pathways, and downscaling techniques to the total SWY variance for the 2040-2064 period. The results showed that the cause-and-effect mechanisms, driving crop yield, shifted from water stress (W-stress) dominated (27 days of W-stress days) during the historical period to nitrogen stress (N-stress) dominated (27 to 35 N-stress days) in the future period. It was shown that while higher precipitation, warmer weather, and early snowmelts, along with elevated CO₂ may favor SWY in cold regions in the future (up to 50% more yields in some sub-basins), the yield potentials may be limited by N-stress (only up to 0.7% yield increase in some sub-basins). The N-stress might be partially related to the N deficiency in the soil, which can be compensated by N fertilizer application. However, inadequate N uptake due to limited evapotranspiration under elevated atmospheric CO₂ might pose restrictions to SWY potentials even in the least N deficient regions. This study uncovers important information on the understanding of spatiotemporal variability of hydrogeochemical processes driving crop yields and the non-stationary response of yields to changing climate. The results also underscore spatiotemporal variability of N-stress due to N deficiency in the soil or N uptake by crops, both of which may restrain SWY by changes in atmospheric CO₂ concentrations in the future.

Keywords: Hydrologic processes; Nitrogen stress; Temperature stress; Variance decomposition; Water stress.