Evaluating the potential of a novel dual heat-pulse sensor to measure volumetric water use in grapevines under a range of flow conditions

2014 ◽  
Vol 41 (8) ◽  
pp. 874 ◽  
Author(s):  
Kyle R. Pearsall ◽  
Larry E. Williams ◽  
Sean Castorani ◽  
Tim M. Bleby ◽  
Andrew J. McElrone
Keyword(s):  
Water Use ◽  
Sap Flow ◽  
Heat Pulse ◽  
Low Flow ◽  
Ratio Method ◽  
Flow Conditions ◽  
Thompson Seedless ◽  
Flow Measurements ◽  
Highly Correlated ◽  
Weighing Lysimeter

The aim of this study was to validate a novel, dual sap-flow sensor that combines two heat-pulse techniques in a single set of sensor probes to measure volumetric water use over the full range of sap flows found in grapevines. The heat ratio method (HRM), which works well at measuring low and reverse flows, was combined with the compensation heat-pulse method (CHPM) that captures moderate to high flows. Sap-flow measurements were performed on Vitis vinifera L. (cvv. Thompson seedless, Chardonnay and Cabernet Sauvignon) grapevines growing in a greenhouse and in three different vineyards, one of which contained a field weighing lysimeter. The combined heat-pulse techniques closely tracked diurnal grapevine water use determined through lysimetry in two growing seasons, and this was true even at very high flow rates (>6 L vine–1 h–1 for Thompson seedless vines in the weighing lysimeter). Measurements made with the HRM technique under low flow conditions were highly correlated (R2 ~ 0.90) with those calculated using the compensated average gradient method that is used to resolve low flow with the CHPM method. Volumetric water use determined with the dual heat-pulse sensors was highly correlated with hourly lysimeter water use in both years (R2 = 0.92 and 0.94 in 2008 and 2009 respectively), but the nature of the relationship was inconsistent among replicate sensors. Similar results were obtained when comparing grapevine water use determined from sap-flow sensors to miniaturised weighing lysimetry of 2-year-old potted vines and to meteorological estimates for field-grown vines in two additional vineyards. The robust nature of all of the correlations demonstrates that the dual heat-pulse sensors can be used to effectively track relative changes in plant water use, but variability of flow around stems makes it difficult to accurately convert to sap-flow volumes.

scholarly journals The Dual Method Approach (DMA) Resolves Measurement Range Limitations of Heat Pulse Velocity Sap Flow Sensors

Forests ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 46 ◽  
Author(s):  
Michael Forster
Keyword(s):  
Sap Flow ◽  
Entire Range ◽  
Full Range ◽  
Heat Pulse ◽  
Pulse Velocity ◽  
Dual Method ◽  
Ratio Method ◽  
Sap Flux Density ◽  
Flow Measurements ◽  
Method Approach

Sap flow, the movement of fluid in the xylem of plants, is commonly measured with the heat pulse velocity (Vh) family of methods. The observable range of Vh in plants is ~−10 to ~+270 cm/h. However, most Vh methods only measure a limited portion of this range, which restricts their utility. Previous research attempted to extend the range of Vh methods, yet these approaches were analytically intensive or impractical to implement. The Dual Method Approach (DMA), which is derived from the optimal measurement ranges of two Vh methods, the Tmax and the heat ratio method (HRM), also known as the “slow rates of flow” method (SRFM), is proposed to measure the full range of sap flow observable in plants. The DMA adopts an algorithm to dynamically choose the optimal Vh measurement via the Tmax or HRM/SRFM. The DMA was tested by measuring sap flux density (Js) on Tecoma capensis (Thunb.) Lindl., stems and comparing the results against Js measured gravimetrically. The DMA successfully measured the entire range of Vh observed in the experiment from 0.020 to 168.578 cm/h, whereas the HRM/SRFM range was between 0.020 and 45.063 cm/h, and the Tmax range was between 2.049 cm/h and 168.578 cm/h. A linear regression of DMA Js against gravimetric Js found an R2 of 0.918 and error of 1.2%, whereas the HRM had an R2 of 0.458 and an error of 49.1%, and the Tmax had an R2 of 0.826 and an error of 0.5%. Different methods to calculate sapwood thermal diffusivity (k) were also compared with the kVand method showing better accuracy. This study demonstrates that the DMA can measure the entire range of Vh in plants and improve the accuracy of sap flow measurements.

Can heat-pulse sap flow measurements be used as continuous water stress indicators of citrus trees?

2012 ◽  
Vol 31 (5) ◽  
pp. 1053-1063 ◽  
Author(s):  
C. Ballester ◽  
J. Castel ◽  
L. Testi ◽  
D. S. Intrigliolo ◽  
J. R. Castel
Keyword(s):  
Water Stress ◽  
Sap Flow ◽  
Heat Pulse ◽  
Flow Measurements ◽  
Stress Indicators ◽  
Sap Flow Measurements ◽  
Citrus Trees

scholarly journals Water-use dynamics of an alien-invaded riparian forest within the Mediterranean climate zone of the Western Cape, South Africa

2017 ◽  
Vol 21 (9) ◽  
pp. 4551-4562 ◽  
Author(s):  
Bruce C. Scott-Shaw ◽  
Colin S. Everson ◽  
Alistair D. Clulow
Keyword(s):  
South Africa ◽  
Water Use ◽  
Sap Flow ◽  
Riparian Forest ◽  
Riparian Forests ◽  
Ratio Method ◽  
Natural State ◽  
Indigenous Species ◽  
Western Cape ◽  
Selection Of

Abstract. In South Africa, the invasion of riparian forests by alien trees has the potential to affect the country's limited water resources. Tree water-use measurements have therefore become an important component of recent hydrological studies. It is difficult for South African government initiatives, such as the Working for Water (WfW) alien clearing program, to justify alien tree removal and implement rehabilitation unless hydrological benefits are known. Consequently, water use within a riparian forest along the Buffeljags River in the Western Cape of South Africa was monitored over a 3-year period. The site consisted of an indigenous stand of Western Cape afrotemperate forest adjacent to a large stand of introduced Acacia mearnsii. The heat ratio method of the heat pulse velocity sap flow technique was used to measure the sap flow of a selection of indigenous species in the indigenous stand, a selection of A. mearnsii trees in the alien stand and two clusters of indigenous species within the alien stand. The indigenous trees in the alien stand at Buffeljags River showed significant intraspecific differences in the daily sap flow rates varying from 15 to 32 L day−1 in summer (sap flow being directly proportional to tree size). In winter (June), this was reduced to only 7 L day−1 when limited energy was available to drive the transpiration process. The water use in the A. mearnsii trees showed peaks in transpiration during the months of March 2012, September 2012 and February 2013. These periods had high average temperatures, rainfall and high daily vapor pressure deficits (VPDs – average of 1.26 kPa). The average daily sap flow ranged from 25 to 35 L in summer and approximately 10 L in the winter. The combined accumulated daily sap flow per year for the three Vepris lanceolata and three A. mearnsii trees was 5700 and 9200 L, respectively, clearly demonstrating the higher water use of the introduced Acacia trees during the winter months. After spatially upscaling the findings, it was concluded that, annually, the alien stand used nearly 6 times more water per unit area than the indigenous stand (585 mm a−1 compared to 101 mm a−1). This finding indicates that there would be a gain in groundwater recharge and/or streamflow if the alien species are removed from riparian forests and rehabilitated back to their natural state.

scholarly journals Drought Superimposes the Positive Effect of Silver Fir on Water Relations of European Beech in Mature Forest Stands

Forests ◽  
2019 ◽  
Vol 10 (10) ◽  
pp. 897 ◽  
Author(s):  
Magh ◽  
Bonn ◽  
Grote ◽  
Burzlaff ◽  
Pfautsch ◽  
...  
Keyword(s):  
Water Use ◽  
Water Relations ◽  
Sap Flow ◽  
Mixed Stand ◽  
Ratio Method ◽  
Silver Fir ◽  
Pure Stand ◽  
Mixed Stands ◽  
Flow Rates ◽  
Beech Stand

Research Highlights: Investigations of evapotranspiration in a mature mixed beech-fir forest stand do not indicate higher resilience towards intensified drying-wetting cycles as compared with pure beech stands. Background and Objectives: Forest management seeks to implement adaptive measures, for example, the introduction of more drought resistant species into prevailing monospecific stands to minimize forest mortality and monetary losses. In Central Europe this includes the introduction of native silver fir (Abies alba) into monospecific beech (Fagus sylvatica) stands. In order to determine, if the introduction of fir would improve the resilience against drier conditions, this study investigates water relations of a mature pure beech and a mature mixed beech-fir stand under natural as well as reduced water availability. Materials and Methods: Sap flow rates and densities were measured in two consecutive years using the heat ratio method and scaled using stand inventory data and modeling. Results: Transpiration rates estimated from sap flow were significantly higher for beech trees as compared with silver fir which was attributed to the more anisohydric water-use strategy of the beech trees. We estimate that stand evapotranspiration was slightly higher for mixed stands due to higher interception losses from the mixed stand during times of above average water supply. When precipitation was restricted, beech was not able to support its transpiration demands, and therefore there was reduced sap flow rates in the mixed, as well as in the pure stand, whereas transpiration of fir was largely unaffected, likely due to its more isohydric behavior toward water use and access to moister soil layers. Thus, we found the rates of evapotranspiration in the mixed beech-fir stand to be smaller during times with no precipitation as compared with the pure beech stand, which was accountable to the severely reduced transpiration of beech in the mixed stand. Conclusions: We conclude that smaller evapotranspiration rates in the mixed beech-fir stand might not be the result of increased water use efficiency but rather caused by restricted hydraulic conductivity of the root system of beech, making mixed beech-fir stands at this site less resilient towards drought.

THE IMPORTANCE OF SAP FLOW MEASUREMENTS TO ESTIMATE ACTUAL WATER USE OF MESKI OLIVE TREES UNDER DIFFERENT IRRIGATION REGIMES IN TUNISIA

2012 ◽  
Vol 61 (5) ◽  
pp. 645-656 ◽  
Author(s):  
Maurits W. Vandegehuchte ◽  
Mohamed Braham ◽  
Raoul Lemeur ◽  
Kathy Steppe
Keyword(s):  
Water Use ◽  
Sap Flow ◽  
Flow Measurements ◽  
Irrigation Regimes ◽  
Olive Trees ◽  
Sap Flow Measurements

scholarly journals Influence of Tree Age and Variety on Allometric Characteristics and Water Use of Mangifera indica L. Growing in Plantation

2011 ◽  
Vol 2011 ◽  
pp. 1-8 ◽  
Author(s):  
Philip G. Oguntunde ◽  
Johnson T. Fasinmirin ◽  
Nick van de Giesen
Keyword(s):  
West Africa ◽  
Water Use ◽  
Sap Flow ◽  
Growth Parameters ◽  
Mangifera Indica ◽  
Xylem Sap ◽  
Tree Age ◽  
Area Index ◽  
Highly Correlated ◽  
Old Trees

Data on water relations and growth characteristics of mango trees needed for productive plantation management are currently lacking in West Africa. Relationships between allometric properties and water use in mango trees were examined. In addition, the effects on allometric characteristics and xylem sap flow were investigated in a mixed varieties plantation. Tree age explained more than 92% of the variation in stem diameter, over 96% of the variation in height, over 92% of the variation in crown diameter, and more than 97% of the variation in leaf area index of the 60 mango trees sampled. Water use increased from 1.01 kg d-1 to 156.7 kg d-1 from the 2- to the 33-year-old trees for a typical bright day. Sap flow was highly correlated with age under different sky conditions. A power function relating daily sap flow to age yielded an r2 of 0.98 for bright days and 0.87 when combined with rainy day data. The water use and growth parameters of the three cultivars were generally not significantly different. This paper has implications for mango productivity and for orchard water management in potentially dry areas of West Africa.

ARE SAP FLOW MEASUREMENTS USEFUL FOR DETERMINING WATER USE OF FRUIT ORCHARDS, WHEN ABSOLUTE VALUES ARE IMPORTANT?

2013 ◽  
pp. 77-83 ◽  
Author(s):  
N.J. Taylor ◽  
N.A. Ibraimo ◽  
J.G. Annandale ◽  
C.S. Everson ◽  
J.T. Vahrmeijer ◽  
...  
Keyword(s):  
Water Use ◽  
Sap Flow ◽  
Flow Measurements ◽  
Fruit Orchards ◽  
Sap Flow Measurements

scholarly journals Hydrogeology of an alpine rockfall aquifer system and its role in flood attenuation and maintaining baseflow

2014 ◽  
Vol 11 (6) ◽  
pp. 6805-6841 ◽  
Author(s):  
U. Lauber ◽  
P. Kotyla ◽  
D. Morche ◽  
N. Goldscheider
Keyword(s):  
Tracer Tests ◽  
Low Flow ◽  
Flow Conditions ◽  
Flow Measurements ◽  
Aquifer System ◽  
Alpine Regions ◽  
Lag Times ◽  
Alpine Catchments ◽  
Underground Flow ◽  
Flood Attenuation

Abstract. The frequency and intensity of extreme hydrological events in alpine regions is projected to increase with climate change. The goal of this study was to better understand the functioning of aquifers composed of complex alluvial and rockfall deposits in alpine valleys and to quantify the role of these natural storage spaces in flood attenuation and baseflow maintenance. Geomorphological and hydrogeological mapping, tracer tests, and continuous flow measurements were conducted in the Reintal valley (German Alps), where runoff from a karst spring infiltrates into a series of postglacial alluvial/rockfall aquifers. During high-flow conditions, groundwater velocities of 30 m h−1 were determined along 500 m; hydrograph analyses revealed short lag times (5 h) between discharge peaks upstream and downstream from the aquifer series; the maximum discharge ratio downstream (22) and the peak recession coefficient (0.196 d−1) are low compared with other alpine catchments. During low-flow conditions, the underground flow path length increased to 2 km and groundwater velocities decreased to 13 m h−1. Downstream hydrographs revealed a delayed discharge response after 101 h and peaks dampened by a factor of 1.5. These results indicate that alluvial/rockfall aquifers might play an important role in the flow regime and attenuation of floods in alpine regions.

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