Automated measurement of canopy stomatal conductance based on infrared temperature

Blonquist, J. M.; Norman, John M.; Bugbee, Bruce

doi:10.1016/j.agrformet.2009.10.003

Cited by 72 publications

(76 citation statements)

References 70 publications

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“…The stomata controls evaporative cooling of the leaves based on soil water status and prevailing environmental conditions. It closes due to increased water deficits and a reduction in plant transpiration causing an increase in plant canopy temperature [91]. The measurement of the crop canopy temperature by infrared thermometry which is then normalized using an index such as the crop water stress index (CWSI) can be used in determining the plant water status and its response to water deficits [79].…”

Section: Thermal Sensingmentioning

confidence: 99%

Advanced Monitoring and Management Systems for Improving Sustainability in Precision Irrigation

et al. 2017

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Globally, the irrigation of crops is the largest consumptive user of fresh water. Water scarcity is increasing worldwide, resulting in tighter regulation of its use for agriculture. This necessitates the development of irrigation practices that are more efficient in the use of water but do not compromise crop quality and yield. Precision irrigation already achieves this goal, in part. The goal of precision irrigation is to accurately supply the crop water need in a timely manner and as spatially uniformly as possible. However, to maximize the benefits of precision irrigation, additional technologies need to be enabled and incorporated into agriculture. This paper discusses how incorporating adaptive decision support systems into precision irrigation management will enable significant advances in increasing the efficiency of current irrigation approaches. From the literature review, it is found that precision irrigation can be applied in achieving the environmental goals related to sustainability. The demonstrated economic benefits of precision irrigation in field-scale crop production is however minimal. It is argued that a proper combination of soil, plant and weather sensors providing real-time data to an adaptive decision support system provides an innovative platform for improving sustainability in irrigated agriculture. The review also shows that adaptive decision support systems based on model predictive control are able to adequately account for the time-varying nature of the soil-plant-atmosphere system while considering operational limitations and agronomic objectives in arriving at optimal irrigation decisions. It is concluded that significant improvements in crop yield and water savings can be achieved by incorporating model predictive control into precision irrigation decision support tools. Further improvements in water savings can also be realized by including deficit irrigation as part of the overall irrigation management strategy. Nevertheless, future research is needed for identifying crop response to regulated water deficits, developing improved soil moisture and plant sensors, and developing self-learning crop simulation frameworks that can be applied to evaluate adaptive decision support strategies related to irrigation.

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Section: Thermal Sensingmentioning

confidence: 99%

Advanced Monitoring and Management Systems for Improving Sustainability in Precision Irrigation

et al. 2017

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“…That is, below this value the crop transpiration was being limited by a water shortage or worse weather conditions, and the canopy cooling capacity would be limited. Thus, decreased water uptake closes stomata, lowering transpiration and raising leaf temperatures [15,16,40].…”

Section: Relating Thermal Canopy Temperature To Other Physiological Pmentioning

confidence: 99%

“…In crop transpiration, latent heat is given off as evaporation, decreasing the canopy temperature (T C ) with respect to air temperature (T air ) [14]. When the crop is subjected to water stress the transpiration level declines, increasing the T C with regard to T air , which is linked with lower crop evapotranspiration and stomatal conductance [15,16].…”

Section: Introductionmentioning

confidence: 99%

Approach to assess infrared thermal imaging of almond trees under water-stress conditions

García-Tejero¹,

Durán-Zuazo²,

Arriaga³

et al. 2012

Fruits

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-Introduction. Optimising agricultural water use implies the combination of physiological, technological and engineering techniques, especially those for continuously monitoring the water status of plants subjected to deficit irrigation. A methodology to estimate water stress of young almond trees from thermal images was developed based on assessing the physiological status of almond crops under limited water-supply conditions. Materials and methods. Two irrigation treatments were tested during the maximum evapotranspirative demand period (214th to the 243rd day of the year) in an experimental almond [Prunus dulcis (Mill) D.A. Webb, cv. Guara] orchard: a low-frequency deficit irrigation (LFDI) treatment, irrigated according to the plant-water status, and a fully irrigated treatment (C 100 ) at 100% of crop evapotranspiration. Daily canopy temperature at midday (T C ) was measured with an infrared camera, together with standard measurements of stem-water potential (Ψ Stem ) and stomatal conductance (g S ). The time course of these parameters and their relationships were analysed. Results and discussion. The time course of the parameters studied showed highly significant correlations among the differentials of canopy-air temperature (ΔT), Ψ Stem and g S . The methodological protocol for analysing thermal images allowed a time saving in processing information and additionally offered the possibility of estimating the Ψ Stem and g S values. Conclusion. Our results confirm that infrared thermography is a suitable technique for assessing the crop-water status and can be used as an important step towards automated plant-water stress management in almond orchards.Spain / Prunus dulcis / canopy / temperature / infrared thermography / water requirements / soil water deficit Approche pour évaluer l'imagerie thermique infrarouge d'amandiers en conditions de stress hydrique.Résumé -Introduction. Optimiser l'utilisation de l'eau en agriculture implique de combiner des techniques physiologiques, technologiques et d'ingénierie, en particulier celles qui permettent de surveiller en permanence l'état hydrique de plantes soumises à un déficit d'irrigation. Une méthodologie pour estimer le stress hydrique de jeunes amandiers à partir d'images thermiques a été développée sur la base de l'évaluation de l'état physiologique d'arbres placés en conditions d'alimentation en eau limitée. Matériel et méthodes. Deux traitements d'irrigation ont été testés au cours de la période de demande evapotranspirative maximale (214e au 243e jour de l'année) dans un dispositif expérimental en verger d'amandiers [Prunus dulcis (Mill.) D.A. Webb., cv. Guara] : un traitement avec une irrigation déficitaire à basse fré-quence (LFDI), irrigué en fonction du statut hydrique des plants, et un traitement irrigué à 100 % de l'éva-potranspiration des cultures (C 100 ). La température quotidienne du couvert à midi (T C ) a été mesurée à l'aide d'une caméra infrarouge, ainsi que des mesures standards du potentiel hydrique de la tige (Ψ Stem ) et de la con...

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“…Canopy temperature based irrigation strategies such as the Time Temperature Threshold [16] [19] or the Biologically-Identified Optimal Thermal Interactive Console systems [20] that were developed and tested in semi-arid environments suffer from the drawback that ambient air temperature, humidity, and solar radiation also influence canopy temperature. High humidity has been both theoretically and empirically shown to be a confounding factor; when humidity is high, such systems tend to overestimate crop stress [19]- [22]. This limits attempts to extend such schemes to humid field environments or greenhouse production settings.…”

Section: Introductionmentioning

confidence: 99%

Relating Xylem Cavitation to Gas Exchange in Cotton

Gitz¹,

Baker²,

Lascano³

2015

AJPS

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Acoustic emissions (AEs) from xylem cavitation events are characteristic of transpiration processes. Though a body of work exists describing AEs and limited stem hydraulic conductivity under water stress, there is limited information about the effects of AEs on stomatal aperture and limitation on carbon assimilation. The objective of this work was to relate AEs to drought stress in cotton. Cotton was grown in mini-lysimeters in the greenhouse and instrumented with a portable photosynthesis system and ultrasonic transducers connected to a digital signal-processing unit. Whole plant transpiration, leaf level gas exchange and ultrasonic AEs were measured. Xylem cavitation events temporally associated with the onset of drought stress. The results are consistent with stomatal closure in response to reduced hydraulic conductance from xylem cavitation events. Clear direct empirical evidence of a reduction in carbon assimilation associated with xylem cavitation resulting from water stress is presented.

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Automated measurement of canopy stomatal conductance based on infrared temperature

Cited by 72 publications

References 70 publications

Advanced Monitoring and Management Systems for Improving Sustainability in Precision Irrigation

Advanced Monitoring and Management Systems for Improving Sustainability in Precision Irrigation

Approach to assess infrared thermal imaging of almond trees under water-stress conditions

Relating Xylem Cavitation to Gas Exchange in Cotton

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