Articles
Drivers of apple tree transpiration rates assessed by sap flow sensors
Article number
1373_4
Pages
19 – 24
Language
English
Abstract
A precise assessment of tree transpiration (T) rates occurring under different environmental conditions is of pivotal importance to improve water management strategies in horticulture.
In this study, we continuously measured, by means of the heat balance ratio method (SFM1, ICT International), the sap flow velocity of field grown apple trees (Nicoter on M9) under differential soil water availability.
The objectives were to analyse the sap-flow derived T fluxes (Tsap) as affected by the changes of tree leaf area, climatic conditions and soil water content.
Soon after budburst, T fluxes increased sharply according to leaf area development, accounting for 35% at blooming and 80% at fruit set of the maximum tree transpiration rate, reached at the end of May (fruit erect phenological stage). During the summer, daily Tsap was mainly affected by PAR and VPD. No change in the diurnal pattern of sap flow rates was observed under field conditions when soil water potential ranged from 0 to -60 kPa, suggesting that, up to this threshold, no physiological limitations related to the soil water status are occurring.
Sensors appeared very effective and consistent among all monitored trees, in measuring the typical diurnal pattern of sap-flow velocity, as well as in capturing its variation occurring whenever a sudden change of weather conditions was happening within the same day.
They, however, need to be calibrated on every single tree to provide a quantitative estimate of total tree transpiration.
In this study, we continuously measured, by means of the heat balance ratio method (SFM1, ICT International), the sap flow velocity of field grown apple trees (Nicoter on M9) under differential soil water availability.
The objectives were to analyse the sap-flow derived T fluxes (Tsap) as affected by the changes of tree leaf area, climatic conditions and soil water content.
Soon after budburst, T fluxes increased sharply according to leaf area development, accounting for 35% at blooming and 80% at fruit set of the maximum tree transpiration rate, reached at the end of May (fruit erect phenological stage). During the summer, daily Tsap was mainly affected by PAR and VPD. No change in the diurnal pattern of sap flow rates was observed under field conditions when soil water potential ranged from 0 to -60 kPa, suggesting that, up to this threshold, no physiological limitations related to the soil water status are occurring.
Sensors appeared very effective and consistent among all monitored trees, in measuring the typical diurnal pattern of sap-flow velocity, as well as in capturing its variation occurring whenever a sudden change of weather conditions was happening within the same day.
They, however, need to be calibrated on every single tree to provide a quantitative estimate of total tree transpiration.
Authors
D. Zanotelli, A. Ben Abdelkader, M. Thalheimer, A. Brignach, N. Giuliani, D. Asensio, C. Andreotti, M. Tagliavini
Keywords
sap-flow, heat ratio method, transpiration, deficit irrigation, climatic variables, phenology
Groups involved
- Division Plant-Environment Interactions in Field Systems
- Division Temperate Tree Fruits
- Division Temperate Tree Nuts
- Division Precision Horticulture and Engineering
- Division Vegetables, Roots and Tubers
- Division Ornamental Plants
- Division Tropical and Subtropical Fruit and Nuts
- Division Vine and Berry Fruits
- Division Greenhouse and Indoor Production Horticulture
- Division Landscape and Urban Horticulture
- Commission Agroecology and Organic Farming Systems
Online Articles (30)