Soya bean's growing area has increased in Hungary since the 2000s, yet few direct field‐based evapotranspiration measurements are available. Compensation evapotranspirometer was used to control two watering levels (unlimited and water stress limited to flowering) at Hungary (45°N), in a three‐season study (2017–2019). Two soya bean varieties with different water demands, Sinara and Sigalia, were analysed. During these vegetation periods, the total evapotranspiration in unlimited water level (both varieties) was above 600 mm, while water stress during flowering reduced it to about half. Water losses in the wet 2018 were slightly lower than during the dry 2017 and 2019. Correlation coefficient values between evapotranspiration and weather variables implied that water losses were controlled by available energy and relative humidity in dry and wet seasons, respectively. Using easily accessible meteorological variables, the air temperature was found to be the best estimator of evapotranspiration. Due to water stress under flowering, the seasonal mean yields varied irregularly in both varieties. Irrespective to season, the water productivity for grain showed a trend to lower values in unlimited watering compared to water stress conditions. Crop‐water response in both soya bean varieties would offer valuable information for breeders and seed distributors in identifying better varieties under mild continental climate.

中文翻译：

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受天气影响的无限制和水分胁迫条件下的大豆（Glycine max L.）蒸散

自2000年代以来，匈牙利的大豆种植面积有所增加，但是很少有基于田间直接蒸散的直接测量方法。在一项为期三季的研究（2017-2019年）中，使用了补偿蒸发蒸散仪来控制匈牙利（45°N）的两个浇水水平（无限，水分胁迫仅限于开花）。锡纳拉（Sinara）和锡加利亚（Sigalia）这两种水分需求不同的大豆品种被分析。在这些植被时期，无限水位（两个品种）的总蒸散量都在600毫米以上，而开花期间的水分胁迫将其减少到一半左右。2018年潮湿季节的水损失略低于2017年干旱年份和2019年的水损失。蒸散量与天气变量之间的相关系数值表明，水分损失分别受干旱和潮湿季节的可用能量和相对湿度控制。使用容易获得的气象变量，发现气温是蒸散量的最佳估计值。由于开花期间的水分胁迫，两个品种的季节性平均产量无规律地变化。与季节无关，与水分胁迫条件相比，无限制浇水时谷物的水分生产率呈现降低的趋势。