In order to contribute knowledge on the method used to calculate the actual crop evapotranspiration, soil, crop, atmosphere, and water spatial structure were integrated into a complete system. Based on the energy balance equation and aerodynamic equation, the meteorological data was reduced and the crop physiological parameter was increased, then the crop evapotranspiration calculation model under natural conditions was derived. The crop evapotranspiration calculation model was verified by the water balance formula using data generated from corn, potato, and flue-cured tobacco grown under field conditions for three consecutive years from 2017 to 2019. The results showed that: from 2017 to 2019, the average root mean square error for measured and calculated evapotranspiration of corn, potato, and flue-cured tobacco at different growth times were 0.5948, 0.4753, and 0.3326, respectively, the mean deviation, mean absolute error, and mean relative error were small, and the coefficient of determination and consistency index were both greater than 0.9100. The measured and calculated crop evapotranspiration of the selected crops increased at first and then decreased gradually as the crops matured, and finally decreased to harvest evapotranspiration, showing a parabolic trend. The crop evapotranspiration calculation model not only reflects the actual evapotranspiration of crops at different growth time but also reflects the change law of actual crop evapotranspiration. The model does not need the correction of soil moisture content, irrigation method, and crop coefficient and can directly calculate the actual crop evapotranspiration. It has the characteristics of consistency between the calculated value and the measured value, strong applicability, simple calculation process, and high accuracy and has the best effect on monitoring soil moisture and crop water shortage sensitivity. The model is significance in that it guides for monitoring soil moisture, determining actual crop evapotranspiration, crop water shortage index, and high yield and efficiency under water-saving conditions.

中文翻译：

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作物蒸散计算模型的建立及验证

为了贡献用于计算实际作物蒸散的方法的知识，将土壤、作物、大气和水空间结构整合到一个完整的系统中。基于能量平衡方程和空气动力学方程，减少气象数据，增加作物生理参数，推导出自然条件下作物蒸散计算模型。利用2017-2019年连续三年大田条件下种植的玉米、马铃薯和烤烟数据，通过水分平衡公式对作物蒸散计算模型进行验证。结果表明：2017-2019年平均玉米、马铃薯、烤烟不同生长时期蒸散量的实测和计算均方根误差均为0。分别为5948、0.4753和0.3326，平均偏差、平均绝对误差和平均相对误差较小，决定系数和一致性指数均大于0.9100。实测计算的所选作物蒸散量随作物成熟先增加后逐渐降低，最后下降至收获蒸散量，呈抛物线趋势。作物蒸散量计算模型不仅反映了作物在不同生长时期的实际蒸散量，而且反映了实际作物蒸散量的变化规律。该模型不需要对土壤含水量、灌溉方式、作物系数进行修正，可以直接计算出实际作物蒸散量。具有计算值与实测值一致、适用性强、计算过程简单、精度高等特点，在监测土壤水分和作物缺水敏感性方面效果最好。该模型对监测土壤水分、确定作物实际蒸散量、作物缺水指数、节水条件下的高产高效具有指导意义。