Sap flow index as an indicator of plant water status

Nadezhdina, N.

doi:10.1093/treephys/19.14.960

Cited by 13 publications

(19 citation statements)

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“…Briefly, the method is based on the observed changes of artificial heat field around the linear heater in stems depending on the sap flow rate and xylem tissue properties (Nadezhdina and Cermák, 1999). The heat field is almost circular around a linear heater inserted in the xylem along stem radius under zero flow, but is getting asymmetrical (prolonged in axial direction and shortened in tangential direction) under conditions of usual flow rates as verified in situ using the network of miniature thermometers (Nadezhdina, 1999) and the infra-red camera (Nadezhdina et al, 2000). The main points of the heat field were characterised by temperature differences, measured by a series of thermocouples inserted in the stem at the axial direction (up and down the heater, dT sym ) and at the tangential direction (on the sides of the heater, dT asym ).…”

Section: Measurement Of Sap Flow Ratesmentioning

confidence: 97%

Water flux estimates from a Belgian Scots pine stand: a comparison of different approaches

Meiresonne

Sampson

Kowalski

et al. 2003

Journal of Hydrology

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Four distinct approaches, that vary markedly in the spatial and temporal resolution of their measurement and process-level outputs, are used to investigate the daily and seasonal water vapour exchange in a 70-year-old Belgian Scots pine forest. Transpiration, canopy interception, soil evaporation and evapotranspiration are simulated, using a stand-level process model (SECRETS) and a soil water balance model (WAVE). Simulated transpiration was compared with up-scaled sap flow measurements and simulated evapotranspiration to eddy covariance measurements.Reasonable agreement in the temporal trends and in the annual water balance between the two models was observed, however daily and weekly predictions often diverged. Most notably, WAVE estimated very low, to no transpiration during late autumn, winter and early spring when incident radiation fell below ,50 W m 22 while SECRETS simulated low (0.1-0.4 mm day 21 ) fluxes during the same period. Both models exhibited similar daily trends in simulated transpiration when compared with sap flow estimates, although simulations from SECRETS were more closely aligned. In contrast, WAVE over-estimated transpiration during periods of no rainfall and under-estimated transpiration during rainfall. Yearly, total evapotranspiration simulated by the models were similar, i.e. 658 mm (1997) and 632 mm (1998) for WAVE and 567 mm (1997) and 619 mm (1998) for SECRETS.Maximum weekly-average evapotranspiration for WAVE exceeded 5 mm day 21 , while SECRETS never exceeded 4 mm day 21 . Both models, in general, simulated higher evapotranspiration than that measured with the eddy covariance technique. An impact of the soil water content in the direct relationship between the models and the eddy covariance measurements was found.The results suggest that: (1) differentmodel formulations can reproduce similar results dependingon the scale at which outputs are resolved, (2) SECRETS estimates of transpiration were well correlated with the empirical measurements, and (3) neither model fitted favourably to the eddy covariance technique. q

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Section: Measurement Of Sap Flow Ratesmentioning

confidence: 97%

Water flux estimates from a Belgian Scots pine stand: a comparison of different approaches

Meiresonne

Sampson

Kowalski

et al. 2003

Journal of Hydrology

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“…For the correct use of terms, units and symbols related to sap flow, the papers by Edwards et al [91] and Lemeur et al [92] are recommended. Sap flow-related measurements are widely used in research for in situ determinations of plant water consumption and transpiration dynamics (Figure 7), and their potential for irrigation scheduling has been assessed by Nadezhdina [93], Fernández et al [94,95] and Jones [30], among others. Devices to schedule irrigation automatically from sap flow measurements have been designed and tested in fruit tree orchards [96,97], and comparisons with other methods to monitor plant water stress and to schedule irrigation have been made for a variety of crops, including apple [93], grapes [98], lemon [99], plum [100] and olive [101,102], among other species.…”

Section: Sap Flowmentioning

confidence: 99%

“…This explains the use of alternative water stress indicators derived from sap flow-related measurements. Nadezhdina and Čermák [96] used what they called the Sap Flow Index (see Nadezhdina [93] for details) to control irrigation in fruit tree orchards. Both Fernández et al [94] and Nadezhdina et al [105] suggested the possibility of using the ratio of sap flow in the inner/outer xylem regions as a trigger for when to Sap flow sensors are robust and reliable enough for operation in the field over extended periods of time, and they are easily automated and implemented with data transmission systems.…”

Section: Sap Flowmentioning

confidence: 99%

Plant-Based Methods for Irrigation Scheduling of Woody Crops

Fernández

2017

Horticulturae

139

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Abstract:The increasing world population and expected climate scenarios impel the agricultural sector towards a more efficient use of water. The scientific community is responding to that challenge by developing a variety of methods and technologies to increase crop water productivity. Precision irrigation is intended to achieve that purpose, through the wise choice of the irrigation system, the irrigation strategy, the method to schedule irrigation, and the production target. In this review, the relevance of precision irrigation for a rational use of water in agriculture, and methods related to the use of plant-based measurements for both the assessment of plant water stress and irrigation scheduling, are considered. These include non-automated, conventional methods based on manual records of plant water status and gas exchange, and automated methods where the related variable is recorded continuously and automatically. Thus, the use of methodologies based on the Scholander chamber and portable gas analysers, as well as those of systems for measuring sap flow, stem diameter variation and leaf turgor pressure, are reviewed. Other methods less used but with a potential to improve irrigation are also considered. These include those based on measurements related to the stem and leaf water content, and to changes in electrical potential within the plant. The use of measurements related to canopy temperature, both for direct assessment of water stress and for defining zones with different irrigation requirements, is also addressed. Finally, the importance of choosing the production target wisely, and the need for economic analyses to obtain maximum benefit of the technology related to precision irrigation, are outlined.

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“…This technique is precise and adaptable enough to follow the variation at a daily to seasonal scale. Many sap flow studies have been undertaken for forest trees [4,10,11], ring-porous trees such as oak [20], coniferous trees such as pine and spruce [5,20] and for orchards [1,19]. However, very few authors focused on diffuse-ring trees in wetland environments.…”

Section: Introductionmentioning

confidence: 99%

Sap flow and water transfer in the Garonne River riparian woodland, France: first results on poplar and willow

Lambs¹,

Muller²

2002

Ann. For. Sci.

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-This work is the first attempt at using Granier sap sensors on Populus nigra, Populus x euramericana cv I45/51 and Salix alba for the monitoring of sap flows in an active floodplain over two consecutive years. The main characteristic of these diffuse porous trees is their capacity to use several tree rings for xylem sap transfer. Results showed that the sap flux densities remained homogeneous on the external 4 cm of the trunk, then decreased with depth. For young trees, the active sapwood can represent half of the trunk. Results indicated that in the same environment and at the same age, daily differences existed between the two major native riparian tree species, the black poplar and the white willow. Their maximal sap flux density (2.6-3.6 dm 3 dm -2 h -1 ) was similar to other fast growing trees. The influence of age was the third important screened factor. Sap flow measurements over several months indicated that water uptake was variable throughout the season, depending on water availability, and was more pronounced for older trees. The sap flux densities for the planted poplar (I45/51) ranged from 2.2-2.6 dm 3 dm -2 h -1 (about 90 dm 3 day -1 ) in the wetter spring conditions and dropped to 1.6-1.7 dm 3 dm -2 h -1 (about 60 dm 3 day -1 ) in less favourable conditions. Under the worst conditions, e.g., the especially long drought in the summer of 1998, these values dropped to 1.0-1.2 (about 40 dm 3 day -1 ), and even to 0.35 dm 3 dm -2 h -1 (about 12 dm 3 day -1 ) for a few days. Complementary long-term studies are needed to better understand the complex sap flow changes and to be able to relate them to significant environmental factors. Priority should be given to the long-term monitoring of sap flows at different depths for a correct estimation of actual daily water uptakes by riparian softwood trees. sap flow / riparian forest / water cycle / poplar / willow Résumé -Mesure des flux de sève et des transferts hydriques dans les ripisylves le long de la Garonne ; premiers résultats pour les peupliers et les saules. Ce travail est le premier essai d'utilisation des capteurs de sève de type Granier sur du Populus nigra, du Populus x euramericana cv I45/51 et du Salix alba pour la mesure de flux de sève dans une plaine inondable sur deux années consécutives. La caractéristique principale de ces bois tendres est leur capacité d'utiliser plusieurs cernes annuels pour le transfert de la sève brute. Les résultats montrent que les densités de flux de sève restent homogènes sur les quatre premiers centimètres du tronc, puis décroissent avec la profondeur. Pour les jeunes arbres, la partie active de bois d'aubier peut représenter la moitié du tronc. Les données montrent que pour un même environnement et pour le même âge, des différences journalières existent entre les deux espèces majeures des ripisylves, le peuplier noir et le saule blanc. Leurs valeurs de densité de flux de sève maximale (de 2,6 à 3,6 dm 3 dm -2 h -1 ) sont similaires à d'autres arbres à croissance rapide. L'influence de l'âge a été le tro...

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Sap flow index as an indicator of plant water status

Cited by 13 publications

References 0 publications

Water flux estimates from a Belgian Scots pine stand: a comparison of different approaches

Water flux estimates from a Belgian Scots pine stand: a comparison of different approaches

Plant-Based Methods for Irrigation Scheduling of Woody Crops

Sap flow and water transfer in the Garonne River riparian woodland, France: first results on poplar and willow

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