Understanding the contributions of soil water evaporation (E) and crop transpiration (T) to evapotranspiration (ET) is essential for irrigation management and improving crop water use efficiency. Current methods for partitioning ET are subject to uncertainties, due in part to the scale differences in determining E, T, and ET. In this study, ET of a lysimeter planted with maize (Zea mays L.) was partitioned into E and T using sensors that had compatible measurement scales: E was measured with heat pulse sensors (following the sensible heat balance (SHB) and modified sensible heat balance (MSHB) approaches), and T was measured with sap flow gauges (following the heat-balance sap-flow (HBSF) method). The accuracy of the measurements was evaluated by comparing the sum of E and T values (E + T) to weighing lysimeter ET data. During the study period, E, T, and ET had average values of 0.9, 4.0, and 4.8 mm d⁻¹, respectively, and the fractions of E and T were 19% and 81% of E + T, respectively. In general, the E + T values agreed well with the lysimeter ET data, but slight overestimations and underestimations were observed at relatively small and relatively large ET rates, respectively. By combining the SHB and MSHB approaches and the HBSF method, it is possible to partition ET into E and T with satisfactory accuracy.

了解土壤水分蒸发（E）和作物蒸腾作用（T）对蒸散量（ET）的贡献对于灌溉管理和提高作物水分利用效率至关重要。当前用于划分ET的方法存在不确定性，部分原因是确定E，T和ET时的规模差异。在这项研究中，ET种植了玉米的蒸渗仪（玉蜀黍L.）隔成Ë和Ť使用具有兼容测量尺度传感器：È使用热脉冲传感器（遵循显热平衡（SHB）和改进的显热平衡（MSHB）方法）进行测量，并使用树液流量计测量T（遵循热平衡树液流动（HBSF）方法）。通过将E和T值的总和（E  +  T）与称重溶渗仪ET数据进行比较，可以评估测量的准确性。在研究期间，E，T和ET的平均值分别为0.9、4.0和4.8 mm d ^-1，E和T的分数分别为E  +的 19％和81％T分别。通常，E  +  T值与溶血仪ET数据非常吻合，但是在相对较小和相对较大的ET速率下分别观察到轻微的高估和低估。通过结合SHB和MSHB方法以及HBSF方法，可以以令人满意的精度将ET分为E和T。