Assessing the Options to Improve Regional Wheat Yield in Eastern Canada Using the CSM-CERES-Wheat Model.

Wheat (Triticum aestivum L.) yield is relatively low in eastern Canada. This study aimed to assess fertilizer N management options to improve the regional yield of wheat using the CSM- CERES-Wheat model. The model was adapted to simulate winter wheat by replacing air temperatures wiThestimated temperatures under snow cover, and then the model was evaluated for simulating winter wheat using experimental data collected at two sites and spring wheat at three sites in eastern Canada. Across all the experimental years and sites, the normalized root mean squared error (nRMSE) between simulated and measured yields was 14%. Regional yield under rainfed conditions in the Eastern Ontario Region (a Census of Agriculture unit as a case study) was simulated wiTh0, 1, 1.5, and 2 times the recommended N rate (around 50 kg N ha^-1) and unlimited N for the calibrated cultivars of spring wheat from 1981 to 1999. The simulated average regional yield (in dry matter) wiThthe recommended N rate ranged from 2180 kg ha^-1 for cultivar Hoffman to 2502 kg ha^-1 for AC Brio. BoThwere close to the reported yield of 2440 kg ha^-1, wiThnRMSE values ranging between 20.3 and 16.6%. The simulated regional yields wiThunlimited N were two times that wiThthe recommended N rate, showing a considerable yield gap. Our simulations indicate that regional yield could increase to 3600 kg ha^-1 in the Eastern Ontario Region if the N rate was increased to around 100 kg N ha^-1, although a slight decrease in N use efficiency would occur. In addition, wiThsuch increases in the N fertilization rate, other abiotic factors such as lodging should be evaluated. [ABSTRACT FROM AUTHOR]