Water Regime Monitoring of the Royal Walnut (Juglans regia L.) Using Sap Flow and Dendrometric Measurements

Changes in the distribution of annual rainfall totals, together with the increase in temperature over the last 40 years, are causing more frequent periods of drought, and plants are more often exposed to water stress. The aim of this study was to monitor the effect of different water regimes (irrigated and non-irrigated) of individuals of walnut tree (Juglans regia L.) in a private orchard located in the West of Slovakia. Our research was focused on dendrometric and sap flow measurements in the period from 28 March to 2 June 2019. The results showed differences in the sap flow of walnut trees during the budbreak period: when trees were irrigated, sap flow in the diurnal cycle was around 130 g·h−1 (20.48%), higher than in the non-irrigated treatment. Dendrometric differences between the irrigated and non-irrigated treatments were not significant. The sap flow data in the flowering period of the irrigated variant were slightly higher at 150 g·h−1 (35.62%) than non-irrigated. Dendrometric differences were more significant when the difference between the variants was more than 1.5 mm. Continuation of this research and analysis of the data obtained in the coming years will allow us to evaluate the effects of the environment on fruit trees in the long term.

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Relationships between canopy transpiration, atmospheric conditions and soil water availability—Analyses of long-term sap-flow measurements in an old Norway spruce forest at the Ore Mountains/Germany

Agricultural and Forest Meteorology ◽

10.1016/j.agrformet.2011.04.007 ◽

2011 ◽

Vol 151 (8) ◽

pp. 1023-1034 ◽

Cited By ~ 43

Author(s):

Falko Clausnitzer ◽

Barbara Köstner ◽

Kai Schwärzel ◽

Christian Bernhofer

Keyword(s):

Soil Water ◽

Norway Spruce ◽

Water Availability ◽

Sap Flow ◽

Spruce Forest ◽

Atmospheric Conditions ◽

Flow Measurements ◽

Sap Flow Measurements ◽

Norway Spruce Forest

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SAP FLOW MEASUREMENTS IN FRUIT TREES - ADVANTAGES AND SHORTFALLS OF CURRENTLY USED SYSTEMS

Acta Horticulturae ◽

10.17660/actahortic.1997.449.38 ◽

1997 ◽

pp. 267-272 ◽

Cited By ~ 6

Author(s):

P. Braun

Keyword(s):

Sap Flow ◽

Fruit Trees ◽

Flow Measurements ◽

Sap Flow Measurements

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Technical note: Long-term probe misalignment and proposed quality control using the heat pulse method for transpiration estimations

Hydrology and Earth System Sciences ◽

10.5194/hess-24-2755-2020 ◽

2020 ◽

Vol 24 (5) ◽

pp. 2755-2767 ◽

Cited By ~ 1

Author(s):

Elisabeth K. Larsen ◽

Jose Luis Palau ◽

Jose Antonio Valiente ◽

Esteban Chirino ◽

Juan Bellot

Keyword(s):

Quality Control ◽

Sap Flow ◽

Hydrological Cycle ◽

Individual Performance ◽

Ratio Method ◽

High Temporal Resolution ◽

Flow Measurements ◽

Relative Standard ◽

Sap Flow Measurements

Abstract. Transpiration is a crucial component in the hydrological cycle and a key parameter in many disciplines like agriculture, forestry, ecology and hydrology. Sap flow measurements are one of the most widely used approaches to estimate whole-plant transpiration in woody species; this is due to their applicability in different environments and in a variety of species as well as the fact that continuous high temporal resolution measurements of this parameter are possible. Several techniques have been developed and tested under different climatic conditions and using different wood properties. However, the scientific literature also identifies considerable sources of error when using sap flow measurements that need to be accounted for, including probe misalignment, wounding, thermal diffusivity and stem water content. This study aims to explore probe misalignment as a function of time in order to improve measurements during long-term field campaigns (>3 months). The heat ratio method (HRM) was chosen because it can assess low and reverse flows. Sensors were installed in four Pinus halepensis trees for 20 months. The pines were located in a coastal valley in south-eastern Spain (39∘57′45′′ N 1∘8′31′′ W) that is characterised by a Mediterranean climate. We conclude that even small geometrical misalignments in the probe placement can create a significant error in sap flow estimations. Additionally, we propose that new statistical information should be recorded during the measurement period which can subsequently be used as a quality control of the sensor output. The relative standard deviation and slope against time of the averaged v1v2 were used as quality indicators. We conclude that no general time limit can be set regarding the longevity of the sensors, and this threshold should rather be determined from individual performance over time.

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