Sap flow of pecan trees in a US Southeastern orchard

Sap flow methods are widely used to estimate water use through transpiration in orchards. This study reports for the first time on pecan tree sap flow properties observed in a micro-irrigated orchard in the southeastern US in 2022 and 2023. This new information regarding sap flow properties of South...

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Main Authors: Gengsheng Zhang, Monique Y. Leclerc, Lenny Wells
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-01-01
Series:Frontiers in Agronomy
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Online Access:https://www.frontiersin.org/articles/10.3389/fagro.2024.1513025/full
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author Gengsheng Zhang
Monique Y. Leclerc
Lenny Wells
author_facet Gengsheng Zhang
Monique Y. Leclerc
Lenny Wells
author_sort Gengsheng Zhang
collection DOAJ
description Sap flow methods are widely used to estimate water use through transpiration in orchards. This study reports for the first time on pecan tree sap flow properties observed in a micro-irrigated orchard in the southeastern US in 2022 and 2023. This new information regarding sap flow properties of Southeastern pecan trees sheds some insight on how pecan water use responds to environmental conditions. The daily peak in the sap flow density occurs either before or after the peak in diurnal solar radiation. The latter peaks before that of air temperature and vapor pressure deficit while the peaks of air temperature and vapor pressure deficit occur later than that of solar radiation. Seasonally, the largest sap flow density occurred during both the growth stage of early nut sizing in May-July and the growth stage of nut sizing and early kernel filling in July-August. The sap flow density in 2022 was higher than that in 2023 mainly due to higher vapor pressure deficit that year. While a single anticlockwise loop of hysteresis occurred in the sap flow diurnally varying with solar radiation in 2023, a twin loop of hysteresis of sap flow to solar radiation was observed in 2022. The twin loop happened since the sap flow peak occurred earlier than that of solar radiation, possibly attributed to high morning vapor pressure deficit that year. A single clockwise loop hysteresis was present in both years in the response of sap flow to air temperature and vapor pressure deficit. The hysteretic strength of the sub-diurnal sap flow density against the vapor pressure deficit for the Southeastern pecan is quantified using a hysteresis index. The index is correlated positively with vapor pressure deficit. This suggests that the drier the air, the greater difference for pecan tree sap flow (or transpiration) in the afternoon to be smaller than that in the morning at the same vapor pressure deficit.
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spelling doaj-art-d62974c5e5d64e3ba1e0c0c0fc88746b2025-01-17T11:35:58ZengFrontiers Media S.A.Frontiers in Agronomy2673-32182025-01-01610.3389/fagro.2024.15130251513025Sap flow of pecan trees in a US Southeastern orchardGengsheng Zhang0Monique Y. Leclerc1Lenny Wells2Atmospheric Biometeorology Group, Department of Crop and Soil Sciences, College of Agricultural and Environmental Sciences, The University of Georgia, Griffin, GA, United StatesAtmospheric Biometeorology Group, Department of Crop and Soil Sciences, College of Agricultural and Environmental Sciences, The University of Georgia, Griffin, GA, United StatesDepartment of Horticulture, College of Agricultural and Environmental Sciences, The University of Georgia, Tifton, GA, United StatesSap flow methods are widely used to estimate water use through transpiration in orchards. This study reports for the first time on pecan tree sap flow properties observed in a micro-irrigated orchard in the southeastern US in 2022 and 2023. This new information regarding sap flow properties of Southeastern pecan trees sheds some insight on how pecan water use responds to environmental conditions. The daily peak in the sap flow density occurs either before or after the peak in diurnal solar radiation. The latter peaks before that of air temperature and vapor pressure deficit while the peaks of air temperature and vapor pressure deficit occur later than that of solar radiation. Seasonally, the largest sap flow density occurred during both the growth stage of early nut sizing in May-July and the growth stage of nut sizing and early kernel filling in July-August. The sap flow density in 2022 was higher than that in 2023 mainly due to higher vapor pressure deficit that year. While a single anticlockwise loop of hysteresis occurred in the sap flow diurnally varying with solar radiation in 2023, a twin loop of hysteresis of sap flow to solar radiation was observed in 2022. The twin loop happened since the sap flow peak occurred earlier than that of solar radiation, possibly attributed to high morning vapor pressure deficit that year. A single clockwise loop hysteresis was present in both years in the response of sap flow to air temperature and vapor pressure deficit. The hysteretic strength of the sub-diurnal sap flow density against the vapor pressure deficit for the Southeastern pecan is quantified using a hysteresis index. The index is correlated positively with vapor pressure deficit. This suggests that the drier the air, the greater difference for pecan tree sap flow (or transpiration) in the afternoon to be smaller than that in the morning at the same vapor pressure deficit.https://www.frontiersin.org/articles/10.3389/fagro.2024.1513025/fullpecansap flowdiurnal and seasonal variabilityhysteresishysteresis index
spellingShingle Gengsheng Zhang
Monique Y. Leclerc
Lenny Wells
Sap flow of pecan trees in a US Southeastern orchard
Frontiers in Agronomy
pecan
sap flow
diurnal and seasonal variability
hysteresis
hysteresis index
title Sap flow of pecan trees in a US Southeastern orchard
title_full Sap flow of pecan trees in a US Southeastern orchard
title_fullStr Sap flow of pecan trees in a US Southeastern orchard
title_full_unstemmed Sap flow of pecan trees in a US Southeastern orchard
title_short Sap flow of pecan trees in a US Southeastern orchard
title_sort sap flow of pecan trees in a us southeastern orchard
topic pecan
sap flow
diurnal and seasonal variability
hysteresis
hysteresis index
url https://www.frontiersin.org/articles/10.3389/fagro.2024.1513025/full
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