Comparison of the transpiration part of two sources evapotranspiration model and the measurements of sap flow in the estimation of the transpiration of sweet cherry orchards

• We examine the water demand in high density sweet cherry orchard.
• Sap flow measurement system (heat balance method) was used in the investigation.
• Analysis was made comparing the transpiration part to the measured sap flow data.
• The daily model evaluation depending on the weather condition ranged from 0.2 to 0.6 mm.
• Deviation of input data less than 20% did not do significant difference in output.

The transpiration part of the coupled Shuttleworth–Wallace model was compared to the data measured using the heat balance sap flow method on sweet cherry trees planted in Hungary. The model was validated under various weather conditions. Appropriate consistency was found between the transpiration part of two source, the output of the Shuttleworh–Wallace evapotranspiration model and the measured sap flow data. Although the model underestimates transpiration on cloudy and rainy days as well as on high vapour pressure deficit days, it is suitable for quantifying the water loss of intensive sweet cherry orchards.In our experience, the model evaluation is reliable, but it is necessary to be aware of a 0.5 mm (10%) daily sum difference depending on weather conditions, as well as of a 10–30 min shift in favour of the modelled values. Investigation of the sensitivity of the model by changing the input data for the leaf area index and minimal stomatal resistance showed that a 20% decrease or increase in the above mentioned input data did not lead to any significant deviation, although wider fluctuation produced a notable variance in the result. Our investigation provides data on high density sweet cherry orchards under continental climatic conditions for which little information has been published.