A greater understanding of Moringa (Moringa oleifera Lam.) transpiration (T) can assist in the development of accurate irrigation management tools. This study aimed at quantifying Moringa T by measuring and modelling the sap flow (SF) of intact stems using an improved heat balance technique. The study was conducted during two consecutive seasons (2021–2022 (Season 1) and 2022–2023 (Season 2)) at the Roodeplaat Experimental Farm of the Agricultural Research Council in South Africa. EXO-Skin sap flow sensors were used. Transpiration-related drivers such as weather and plant physiological parameters were measured simultaneously. The measured SF data in Seasons 1 and 2 were used to respectively parameterize and validate a canopy conductance T model. There was a positive correlation between the measured SF and its drivers, evidenced through coefficients of determination (R2) of 0.82, 0.99 and 0.92 for the relationships between SF and short-grass reference evapotranspiration (ETo), stem area and stomatal conductance, respectively. The measured and simulated SF varied from 0.82–1.29 and 0.71–1.19 mm tree−1 day−1 (model parameterization), as well as from 0.77–3.54 and 1.10–3.10 mm tree−1 day−1 (model validation). Despite the slight discrepancies between measured and predicted SF values during model performance evaluation, an acceptable agreement was achieved through root mean square errors (RMSEs) of 0.32 and 0.37 mm day−1 and model efficiencies (Efs) of 0.93 and 0.88, for model parameterization and validation, respectively. The current study showed that the canopy conductance T model has the potential to accurately predict Moringa T and contribute to optimizing irrigation water management.

中文翻译：

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辣木蒸腾的测量和建模以改善灌溉管理


对辣木 （Moringa oleifera Lam.） 蒸腾 （T） 的更深入了解有助于开发准确的灌溉管理工具。本研究旨在通过使用改进的热平衡技术测量和建模完整茎的汁液流 （SF） 来量化辣木 T。该研究在南非农业研究委员会的 Roodeplaat 实验农场连续两个季节（2021-2022 年（第 1 季）和 2022-2023 年（第 2 季））进行。使用了 EXO-Skin 汁液流量传感器。同时测量与蒸腾相关的驱动因素，例如天气和植物生理参数。使用第 1 季和第 2 季实测的 SF 数据分别用于参数化和验证冠层导度 T 模型。测得的 SF 与其驱动因素之间存在正相关，SF 与短草参考蒸散 （ETo）、茎面积和气孔导度之间的关系的决定系数 （R2） 分别为 0.82、0.99 和 0.92。测量和模拟的 SF 在 0.82-1.29 和 0.71-1.19 毫米树-1 天-1（模型参数化）以及 0.77-3.54 和 1.10-3.10 毫米树-1 天-1（模型验证）之间变化。尽管在模型性能评估期间测量和预测的 SF 值之间存在细微差异，但通过模型参数化和验证的均方根误差 （RMSE） 分别为 0.32 和 0.37 mm day-1 和模型效率 （Efs） 和 0.93 和 0.88，实现了可接受的一致性。目前的研究表明，冠层导度 T 模型有可能准确预测辣木 T 并有助于优化灌溉水管理。