Prediction of crop yield, evapotranspiration, and crop water productivity are essential aspects for water management and the sustainable intensification of agriculture. The goal of this study was to evaluate the Cropping System Model (CSM)-CROPGRO-Soybean model for simulating evapotranspiration and crop water productivity of soybean grown in a tropical environment. Energy balance evapotranspiration was measured daily using a Bowen Ratio Energy Balance (BREB) system for irrigated experiments that were conducted in Piracicaba, SP, Brazil, during the 2016-2017 and 2017-2018 growing seasons. Evapotranspiration was simulated with the CROPGRO-Soybean model using either the Priestley–Taylor or the FAO-56 Penman–Monteith method for potential ET combined with either the Ritchie-Two-Stage or the Suleiman–Ritchie soil water evaporation methods. The model provided good predictions of daily (D-statistic > 0.7) and cumulative evapotranspiration (RMSE ranged from 8 to 64 mm). FAO-56 Penman–Monteith with the Ritchie-Two-Stage method provided a better fit than the Priestley–Taylor with Suleiman–Ritchie when compared with measured data. Simulated crop water productivity agreed well with observed, but with a systematic underprediction (variation between simulated and measured ranged from -2.2 to -16.8 %). Simulation of long-term scenarios was conducted for different tropical environments, i.e., Piracicaba and Teresina, with soil tillage and water management practices. The results demonstrated that the implementation of no-tillage can increase 0.1 kg/m³ (11%) crop water productivity for grain. This study also showed that when irrigation was triggered at more than 60% of available soil water, irrigation did not result in an increase in yield despite an increase in water supply.

作物产量、蒸散量和作物水分生产力的预测是水资源管理和农业可持续集约化的重要方面。本研究的目的是评估种植系统模型 (CSM)-CROPGRO-Soybean 模型，用于模拟热带环境中生长的大豆的蒸散和作物水分生产力。在 2016-2017 年和 2017-2018 年生长季节期间，使用鲍文比能量平衡 (BREB) 系统在巴西皮拉西卡巴进行的灌溉实验每天测量能量平衡蒸散量。使用 Priestley-Taylor 或 FAO-56 Penman-Monteith 方法结合 Ritchie-Two-Stage 或 Suleiman-Ritchie 土壤水分蒸发法，使用 CROPGRO-Soybean 模型模拟蒸散。该模型对每日（D 统计量 > 0.7）和累积蒸散量（RMSE 范围从 8 到 64 毫米）提供了良好的预测。与实测数据相比，采用 Ritchie-Two-Stage 方法的 FAO-56 Penman-Monteith 提供了比采用 Suleiman-Ritchie 的 Priestley-Taylor 更好的拟合度。模拟的作物水分生产率与观察结果一致，但系统预测不足（模拟和测量之间的变化范围为 -2.2 至 -16.8 %）。针对不同的热带环境进行了长期情景模拟，模拟的作物水分生产率与观察结果一致，但系统预测不足（模拟和测量之间的变化范围为 -2.2 至 -16.8 %）。针对不同的热带环境进行了长期情景模拟，模拟的作物水分生产率与观察结果一致，但系统预测不足（模拟和测量之间的变化范围为 -2.2 至 -16.8 %）。针对不同的热带环境进行了长期情景模拟，即，Piracicaba 和 Teresina，采用土壤耕作和水资源管理实践。结果表明，实施免耕可提高0.1 kg/m ³ (11%)作物对粮食的水分生产力。这项研究还表明，当灌溉在超过 60% 的可用土壤水分时触发时，尽管供水增加，但灌溉并没有导致产量增加。