Sorghum is an important food and feed crop in the dry lowland areas of Ethiopia. Farmers grow both early-sown long-duration landraces and late-sown short-duration improved varieties. Because timing and intensity of drought stress can vary in space and time, an understanding of major traits (G), environments (E), management (M), and their interactions (G×E×M) is needed to optimize grain and forage yield given the limited available resources. Crop simulation modeling can provide insights into these complex G×E×M interactions and be used to identify possible avenues for adaptation to prevalent drought patterns in Ethiopia. In a previous study predictive phenology models were developed for a range of Ethiopian germplasm. In this study, the aims were to (1) further parameterize and validate the APSIM-sorghum model for crop growth and yield of Ethiopian germplasm, and (2) quantify by simulation the productivity-risk trade-offs associated with early vs late sowing strategies in the dry lowlands of Ethiopia. Field experiments involving Ethiopian germplasm with contrasting phenology and height were conducted under well-watered (Melkassa) and water-limited (Miesso) conditions and crop development, growth and yield measured. Soil characterization and weather records at the experimental sites, combined with model parameterization, enabled testing of the APSIM-sorghum model, which showed good correspondence between simulated and observed data. The simulated productivity for the Ethiopian dry lowlands environments showed trade-offs between biomass and grain yield for early and late sowing strategies. The late sowing strategy tended to produce less biomass except in poor seasons, whereas it tended to produce greater grain yield except in very good seasons. This study exemplified the systems approach to identifying traits and management options needed to quantify the production-risk trade-offs associated with crop adaptation in the Ethiopian dry lowlands and further exemplifies the general robustness of the sorghum model in APSIM for this task.

高粱是埃塞俄比亚干旱低地地区的重要粮食和饲料作物。农民既种植早播的长寿命地方品种，也种植晚播的短寿命改良品种。由于干旱胁迫的时间和强度会因空间和时间而异，因此需要了解主要性状 (G)、环境 (E)、管理 (M) 及其相互作用 (G×E×M) 以优化谷物和饲料产量有限的可用资源。作物模拟建模可以深入了解这些复杂的 G×E×M 相互作用，并用于确定适应埃塞俄比亚普遍干旱模式的可能途径。在之前的一项研究中，针对一系列埃塞俄比亚种质开发了预测物候模型。在这项研究中，目的是 (1) 进一步参数化和验证埃塞俄比亚种质作物生长和产量的 APSIM-高粱模型，以及 (2) 通过模拟量化干旱低地早播和晚播策略相关的生产力风险权衡埃塞俄比亚。在灌溉良好 (Melkassa) 和限水 (Miesso) 条件下进行了涉及具有对比物候和高度的埃塞俄比亚种质的田间试验，并测量了作物发育、生长和产量。实验地点的土壤特性和天气记录，结合模型参数化，使 APSIM-高粱模型的测试成为可能，结果显示模拟数据与观测数据之间具有良好的对应关系。埃塞俄比亚干旱低地环境的模拟生产力表明，早晚播种策略的生物量和谷物产量之间存在权衡。晚播策略往往会产生较少的生物量，除了在糟糕的季节，而它往往会产生更高的谷物产量，除非在非常好的季节。本研究举例说明了系统方法来识别性状和管理选项，以量化与埃塞俄比亚干旱低地作物适应相关的生产风险权衡，并进一步举例说明了 APSIM 中高粱模型对该任务的一般稳健性。