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פותח על ידי קלירמאש פתרונות בע"מ -
Estimating sap flux densities in date palm trees using the heat dissipation method and weighing lysimeters
Year:
2012
Authors :
כהן, שבתאי
;
.
Volume :
32
Co-Authors:
Sperling, O., Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Ben-Gurion University of the Negev, Sede Boqer 84990, Israel
Shapira, O., Northern R and D, Migal, Kiryat shmona 11016, Israel
Cohen, S., Institute of Soil Water, and Environmental Sciences, ARO Volcani Center, Bet-Dagan, Israel
Tripler, E., Department of Soil and Water Sciences, Faculty of Agricultural, Food and Environmental Sciences, Hebrew University of Jerusalem, Rehovot 76100, Israel
Schwartz, A., Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel
Lazarovitch, N., Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Ben-Gurion University of the Negev, Sede Boqer 84990, Israel
Facilitators :
From page:
1171
To page:
1178
(
Total pages:
8
)
Abstract:
In a world of diminishing water reservoirs and a rising demand for food, the practice and development of water stress indicators and sensors are in rapid progress. The heat dissipation method, originally established by Granier, is herein applied and modified to enable sap flow measurements in date palm trees in the southern Arava desert of Israel. A long and tough sensor was constructed to withstand insertion into the date palm's hard exterior stem. This stem is wide and fibrous, surrounded by an even tougher external non-conducting layer of dead leaf bases. Furthermore, being a monocot species, water flow does not necessarily occur through the outer part of the palm's stem, as in most trees. Therefore, it is highly important to investigate the variations of the sap flux densities and determine the preferable location for sap flow sensing within the stem. Once installed into fully grown date palm trees stationed on weighing lysimeters, sap flow as measured by the modified sensors was compared with the actual transpiration. Sap flow was found to be well correlated with transpiration, especially when using a recent calibration equation rather than the original Granier equation. Furthermore, inducing the axial variability of the sap flux densities was found to be highly important for accurate assessments of transpiration by sap flow measurements. The sensors indicated no transpiration at night, a high increase of transpiration from 06:00 to 09:00, maximum transpiration at 12:00, followed by a moderate reduction until 08:00; when transpiration ceased. These results were reinforced by the lysimeters' output. Reduced sap flux densities were detected at the stem's mantle when compared with its center. These results were reinforced by mechanistic measurements of the stem's specific hydraulic conductivity. Variance on the vertical axis was also observed, indicating an accelerated flow towards the upper parts of the tree and raising a hypothesis concerning dehydrating mechanisms of the date palm tree. Finally, the sensors indicated reduction in flow almost immediately after irrigation of field-grown trees was withheld, at a time when no climatic or phenological conditions could have led to reduction in transpiration. © 2012 The Author.
Note:
Related Files :
evapotranspiration
irrigation (agriculture)
Israel
lysimeter
Phoenix dactylifera
transpiration
trees
water
water stress
עוד תגיות
תוכן קשור
More details
DOI :
10.1093/treephys/tps070
Article number:
Affiliations:
Database:
סקופוס
Publication Type:
מאמר
;
.
Language:
אנגלית
Editors' remarks:
ID:
18540
Last updated date:
02/03/2022 17:27
Creation date:
16/04/2018 23:22
Scientific Publication
Estimating sap flux densities in date palm trees using the heat dissipation method and weighing lysimeters
32
Sperling, O., Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Ben-Gurion University of the Negev, Sede Boqer 84990, Israel
Shapira, O., Northern R and D, Migal, Kiryat shmona 11016, Israel
Cohen, S., Institute of Soil Water, and Environmental Sciences, ARO Volcani Center, Bet-Dagan, Israel
Tripler, E., Department of Soil and Water Sciences, Faculty of Agricultural, Food and Environmental Sciences, Hebrew University of Jerusalem, Rehovot 76100, Israel
Schwartz, A., Robert H. Smith Institute of Plant Sciences and Genetics in Agriculture, Faculty of Agriculture, Hebrew University of Jerusalem, Rehovot 76100, Israel
Lazarovitch, N., Wyler Department of Dryland Agriculture, French Associates Institute for Agriculture and Biotechnology of Drylands, Ben-Gurion University of the Negev, Sede Boqer 84990, Israel
Estimating sap flux densities in date palm trees using the heat dissipation method and weighing lysimeters
In a world of diminishing water reservoirs and a rising demand for food, the practice and development of water stress indicators and sensors are in rapid progress. The heat dissipation method, originally established by Granier, is herein applied and modified to enable sap flow measurements in date palm trees in the southern Arava desert of Israel. A long and tough sensor was constructed to withstand insertion into the date palm's hard exterior stem. This stem is wide and fibrous, surrounded by an even tougher external non-conducting layer of dead leaf bases. Furthermore, being a monocot species, water flow does not necessarily occur through the outer part of the palm's stem, as in most trees. Therefore, it is highly important to investigate the variations of the sap flux densities and determine the preferable location for sap flow sensing within the stem. Once installed into fully grown date palm trees stationed on weighing lysimeters, sap flow as measured by the modified sensors was compared with the actual transpiration. Sap flow was found to be well correlated with transpiration, especially when using a recent calibration equation rather than the original Granier equation. Furthermore, inducing the axial variability of the sap flux densities was found to be highly important for accurate assessments of transpiration by sap flow measurements. The sensors indicated no transpiration at night, a high increase of transpiration from 06:00 to 09:00, maximum transpiration at 12:00, followed by a moderate reduction until 08:00; when transpiration ceased. These results were reinforced by the lysimeters' output. Reduced sap flux densities were detected at the stem's mantle when compared with its center. These results were reinforced by mechanistic measurements of the stem's specific hydraulic conductivity. Variance on the vertical axis was also observed, indicating an accelerated flow towards the upper parts of the tree and raising a hypothesis concerning dehydrating mechanisms of the date palm tree. Finally, the sensors indicated reduction in flow almost immediately after irrigation of field-grown trees was withheld, at a time when no climatic or phenological conditions could have led to reduction in transpiration. © 2012 The Author.
Scientific Publication
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