Improved heat balance method for determining sap flow rate

Ishida, Tomoyasu; Campbell, Gaylon S.; Calissendorff, C.

doi:10.1016/0168-1923(91)90103-w

Cited by 53 publications

(40 citation statements)

References 14 publications

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“…Root water uptake of the maize plants was represented by xylem sap flow, which was measured using heat balance method (Campbell 1991;Ishida et al 1991;Jara et al 1998), with the gauges (Dyanmax, SGB25) installed on the base of the plant stems. A Thermodac EF data logger (Model 20520A) was used to record signals every minute for subsequent calculation of sap flow rate.…”

Section: Site Description and Soil Propertiesmentioning

confidence: 99%

Root water uptake and profile soil water as affected by vertical root distribution

et al. 2006

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Water uptake by plant roots is a main process controlling water balance in field profiles and vital for agro-ecosystem management. Based on the sap flow measurements for maize plants (Zea mays L.) in a field under natural wet-and dry-soil conditions, we studied the effect of vertical root distribution on root water uptake and the resulted changes of profile soil water. The observations indicate that depth of the most densely rooted soil layer was more important than the maximum rooting depth for increasing the ability of plants to cope with the shortage of water. Occurrence of the most densely rooted layer at or below 30-cm soil depth was very conducive to maintaining plant water supply under the drysoil conditions. In the soil layers colonized most densely by roots, daytime effective soil water saturation (S e ) always dropped dramatically due to the high-efficient local water depletion. Restriction of the rooting depth markedly increased the difference of S e between the individual soil layers particularly under the dry-soil conditions due likely to the physical non-equilibrium of water flow between the layers. This study highlights the importance of root distribution and pattern in regulating soil water use and thereby improving endurance of plants to seasonal droughts for sustainable agricultural productivity.

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Section: Site Description and Soil Propertiesmentioning

confidence: 99%

Root water uptake and profile soil water as affected by vertical root distribution

et al. 2006

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“…In this experiment, we examined oak seedlings with mean transpiration rates ranging from 2 to 43 g h −1 during the day-time and 100 to 610 g over 48-hour periods. In previous evaluations of the accuracy of sap flow measurements using stem heat balance methods the transpiration rates in the examined material have sometimes been considerably higher (e.g., Dugas et al, 1993;Grime et al, 1995;Ishida et al, 1991;Valangogne and Nasr, 1993). When comparing the variation in the same ranges of transpiration speed during day time, we have approximately the same magnitude of variation compared to other studies (Dugas et al, 1993;Grime et al, 1995aGrime et al, , 1995bKjelgaard et al, 1997;Weibel and de Vos, 1994).…”

Section: Discussionmentioning

confidence: 99%

“…In another method, which is technically more advanced, variable power inputs are used to maintain a constant temperature difference between a heated point and a reference point in the stem (Grime et al, 1995;Ishida et al, 1991). The advantage of this approach is that less power is supplied to the stem during periods with low sap flow rates than during periods with high rates, thereby reducing the overall power input and the likelihood of overheating causing physiological damage.…”

Section: Introductionmentioning

confidence: 99%

Estimation du flux de sève à partir du bilan thermique de la tige de plants de Quercus robur L. en relation avec l’intensité de la lumière : comparaison de deux méthodes au cours de la phase d’installation

Löf¹,

Welander²

2009

Ann. For. Sci.

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Abstract• Knowledge of whole tree seedling water fluxes is important in ecological and forestry research, especially under conditions with low transpiration, but no standard method has yet been established that provides reliable in situ measurements.• The aims were: (1) to assess the performance of two methods for estimating sap-flows in oak seedlings following planting by correlating the data they provided with natural light intensities over a three-week period, and (2) to compare the estimates with transpiration data obtained by weighing pots.• Estimates of sap flows obtained from data provided by constant power (Dayau-type) heat balance gauges under low light conditions (100-450 μmol m −2 s −1 ) were less variable than estimates from variable power (EMS-type) heat balance gauges. The EMS-type system yielded data with little between-gauge variation, but consistently underestimated transpiration on a daily basis, a systematic error that should be corrected by other methods. The Dayau-type gauges yielded data with substantial variations, and several gauges are probably needed in research to cover these variations. Further, both systems provide rather uncertain estimates of short-time (hour) transpiration rates.• However, provided that these considerations are taken into account, we conclude that it should be possible to use either system in various research contexts. Mots-clés :racines / flux de sève / transpiration / bilan hydrique / relations hydriques Résumé -Estimation du flux de sève à partir du bilan thermique de la tige de plants de Quercus robur L. en relation avec l'intensité de la lumière : comparaison de deux méthodes au cours de la phase d'installation.• La connaissance des flux d'eau de l'arbre entier est importante dans la recherche en écologie et en foresterie, en particulier dans des conditions de faible transpiration, mais jusqu'à présent, aucune méthode standard ne procure des mesures fiables in situ.• Les objectifs étaient : (1) d'évaluer la performance de deux méthodes d'estimation des flux de sève en suivant une plantation de semis de chêne et en corrélant les données fournies par ces dernières avec les intensités de lumière naturelle sur une période de trois semaines, et (2) de comparer les estimations de transpiration avec des données obtenues par pesée des pots.• Les estimations de flux de sève obtenues à partir des données fournies par une alimentation constante (Dayau-type) des jauges de bilan thermique sous des conditions de faible luminosité (100-450 μmol m −2 s −1 ) sont moins variables que les estimations des jauges de bilan thermique à puissance variable (EMS-type). Le système EMS-type a fourni des données avec peu de variation entre les jauges, mais a toujours sous-estimé la transpiration sur une base quotidienne, une erreur systéma-tique qui doit être corrigé par d'autres méthodes. Les jauges de type Dayau ont fourni des données avec des variations importantes, et plusieurs jauges sont probablement nécessaires pour la compré-hension de ces variations. En outre, les deux systèmes ...

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“…Heat balance gauges (Ishida et al, 1991;Khan and Ong, 1995) were used to measure sap flux in grevillea trees before and after removing the soil within the crop rooting zone to a depth of 60 cm from around the base of the trees to prevent any water uptake except from beneath this zone. Sap flux was also measured before and after pruning grevillea trees to establish whether water uptake was demand or supply-limited.…”

Section: Leucaena Leucocephalamentioning

confidence: 99%

Using sap flow gauges to quantify water uptake by tree roots from beneath the crop rooting zone in agroforestry systems

et al. 1996

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Abstract. Grevillea (GreviUea robusta A. Cunn.; Proteaceae) is used in agroforestry in many areas of the highlands of East and Central Africa, and is reported to be mainly deep rooted, with few shallow roots and correspondingly low levels of competition with associated crops for water and nutrients. To examine the extent of below-ground complementarity in water use between grevillea and cowpea (Vigna unguiculata L.; Leguminosae), experiments were carried out at the International Centre for Research in Agroforestry (ICRAF) Field Centre at Machakos, Kenya. Sap flux was measured using heat balance gauges attached to the stems of young grevillea trees (10-18 months old), both before and after excavating the crop rooting zone (upper 60 cm of soil) around the stem base, in order to establish the capacity of the grevillea to extract water from below this zone. After excavation, the trees maintained sap fluxes of up to 85% of the unexcavated values, suggesting a high degree of below-ground complementarity.

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Improved heat balance method for determining sap flow rate

Cited by 53 publications

References 14 publications

Root water uptake and profile soil water as affected by vertical root distribution

Root water uptake and profile soil water as affected by vertical root distribution

Estimation du flux de sève à partir du bilan thermique de la tige de plants de Quercus robur L. en relation avec l’intensité de la lumière : comparaison de deux méthodes au cours de la phase d’installation

Using sap flow gauges to quantify water uptake by tree roots from beneath the crop rooting zone in agroforestry systems

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