. 2015. Upscaling modelled crop yields to regional scale: A case study using DSSAT for spring wheat on the Canadian prairies. Can. J. Soil Sci. 95: 49Á61. Dynamic crop models are often operated at the plot or field scale. Upscaling is necessary when the process-based crop models are used for regional applications, such as forecasting regional crop yields and assessing climate change impacts on regional crop productivity. Dynamic crop models often require detailed input data for climate, soil and crop management; thus, their reliability may decrease at the regional scale as the uncertainty of simulation results might increase due to uncertainties in the input data. In this study, we modelled spring wheat yields at the level of numerous individual soils using the CERESÁWheat model in the Decision Support System for Agrotechnology Transfer (DSSAT) and then aggregated the simulated yields from individual soils to regions where crop yields were reported. A comparison between the aggregated and the reported yields was performed to examine the potential of using dynamic crop models with individual soils in a region for the simulation of regional crop yields. The regionally aggregated simulated yields demonstrated reasonable agreement with the reported data, with a correlation coefficient of 0.71 and a root-mean-square error of 266 kg ha(1 (i.e., 15% of the average yield) over 40 regions on the Canadian prairies. Our conclusion is that aggregating simulated crop yields on individual soils with a crop model can be reliable for the estimation of regional crop yields. This demonstrated its potential as a useful approach for using crop models to assess climate change impacts on regional crop productivity.Key words: CERES-Wheat crop model, spring wheat, yield aggregation, regional application (Canada) Huffman, T., Qian, B., De Jong, R., Liu, J., Wang, H., McConkey, B., Brierley, T. et Yang, J. 2015. Mise a`l'e´chelle re´gionale des mode`les du rendement des cultures : e´tude de cas avec le DSSAT pour le ble´de printemps cultive´dans les Prairies canadiennes. Can. J. Soil Sci. 95: 49Á61. On recourt souvent aux mode`les agricoles dynamiques a`l'e´chelle de la parcelle ou du champ. Toutefois, une mise a`l'e´chelle s'impose quand on utilise les mode`les articule´s sur les processus pour des applications re´gionales comme la pre´vision du rendement des cultures ou l'e´valuation de l'impact du changement climatique sur la productivite´des cultures dans une re´gion. Les mode`les agricoles dynamiques ont souvent besoin de donne´es de´taille´es sur le climat, le sol et les pratiques agronomiques. C'est pourquoi leur fiabilite´diminue a`l'e´chelon re´gional, l'incertitude des re´sultats de la simulation pouvant s'accroıˆtre avec les incertitudes associe´es aux donne´es saisies. Dans le cadre de cette e´tude, les auteurs ont mode´lise´le rendement du ble´de printemps au niveau de nombreux sols individuels en recourant au mode`le CERES du ble´dans le syste`me d'aide a`la prise de de´cisions pour le transfert des technologies agricoles (...