Abstract Canada is one of the top wheat grain exporters, with a share of more than 10% in the world wheat market. The majority of Canadian wheat production takes place in the Prairies where 6.2 million ha of the area is seeded to spring wheat. The climate is semiarid with an estimated precipitation deficit of about 300 mm during the crop growing season, indicating that water is the primary limiting factor for crop production. In this study, three DSSAT-Wheat models (CSM-CERES, -CROPSIM, -NWHEAT) were used to quantify the impacts of water management practices on crop water stress and wheat yields. The models were evaluated individually and as an ensemble against observed wheat performance using three field experiments conducted to investigate irrigation, rainfed, and summer fallow impacts on wheat yields. The results showed that all three wheat models well simulated grain yield gains with irrigation and summer fallow that conserved additional soil water. Statistically, the multimodel ensemble improved the accuracy in simulating grain yields and biomass of spring wheat under both irrigated and rainfed conditions. The improvements could not be linked to eco-physiological processes in crop systems, and the increased simulation accuracy was likely due to the offsetting effects of simulation bias and errors from the individual models. Water input (precipitation + irrigation) of 400 mm was sufficient to reach the highest yield of spring wheat cultivars in the Canadian Prairies. Irrigation of 200 mm was able to alleviate most of the crop water stress in the study region. Further simulation scenarios showed that irrigating spring wheat when soil moisture was below 50% of available water capacity (AWC) for plants led to high yield, low irrigation rates, and reduced evaporation for different soil textures. Combined with improved drought tolerance varieties, this irrigation regime provides good prospects for increasing wheat yield and water use efficiency.

中文翻译：

---

使用 DSSAT 小麦模型评估水管理对加拿大大草原春小麦产量的影响

摘要 加拿大是最大的小麦谷物出口国之一，在世界小麦市场上的份额超过 10%。加拿大小麦的大部分生产发生在大草原地区，该地区有 620 万公顷的土地种植春小麦。气候是半干旱的，在作物生长季节估计降水不足约 300 毫米，表明水是作物生产的主要限制因素。在本研究中，三个 DSSAT-Wheat 模型（CSM-CERES、-CROPSIM、-NWHEAT）用于量化水资源管理实践对作物水分胁迫和小麦产量的影响。使用三个田间试验对这些模型进行单独评估，并作为一个整体与观察到的小麦性能进行评估，以研究灌溉、雨育和夏季休耕对小麦产量的影响。结果表明，所有三种小麦模型都很好地模拟了灌溉和夏季休耕保存额外土壤水分的谷物产量增加。从统计上看，多模型集合提高了在灌溉和雨育条件下模拟春小麦粮食产量和生物量的准确性。这些改进与作物系统中的生态生理过程无关，模拟精度的提高可能是由于模拟偏差和来自各个模型的错误的抵消效应。400 毫米的水输入（降水+灌溉）足以达到加拿大大草原春小麦品种的最高产量。200 毫米的灌溉能够缓解研究区域的大部分作物水分胁迫。进一步的模拟情景表明，当土壤水分低于植物可用水容量 (AWC) 的 50% 时，灌溉春小麦会导致高产、低灌溉率和不同土壤质地的蒸发量减少。结合改良的耐旱品种，这种灌溉制度为提高小麦产量和水资源利用效率提供了良好的前景。