Influence of leaf water potential on diurnal changes in CO2 and water vapour fluxes

Yu, Qiang; Xu, Shouhua; Wang, Jing; Lee, Xuhui

doi:10.1007/s10546-007-9164-y

Cited by 11 publications

(8 citation statements)

References 52 publications

(67 reference statements)

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“…In the SHAW-Pn model, plant respiration was related to air temperature, and soil respiration was expressed as a function of soil temperature at 5 cm beneath the surface. The values of Q were adopted from Yu et al (2007).…”

Section: Stomatal Modelsmentioning

confidence: 99%

“…Soil heat flux was measured with a heat flux sensor (HFPO1, Hukseflux, Netherlands) installed 0.05 in below soil surface. Data from the site had good energy balance closure during periods of weak advection (Lee and Yu, 2004;Yu et al, 2007) and were used for model comparison.…”

Section: Flux Measurementmentioning

confidence: 99%

“…Finally, net radiation, water, sensible heat, and CO. fluxes over the crop field were simulated by the coupled SHAW-Pn model. Soil physical and plant physiological parameters used in the simulations were adapted from Yu of al. (2007).…”

Section: Model Tests and Validationmentioning

confidence: 99%

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Extending the Simultaneous Heat and Water (SHAW) Model to Simulate Carbon Dioxide and Water Fluxes over Wheat Canopy

Flerchinger

2015

Response of Crops to Limited Water

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Energy, water, and CO 2 fluxes at the soil-atmosphere interface are of key interest among ecosystem researchers. The Simultaneous Heat and Water (SHAW) Model describes radiation energy balance, heat transfer, and water movement within the soil-plant-atmosphere continuum but has no plant growth or carbon assimilation modules. This study coupled the components of solar radiation and water transfer within a plant canopy in SHAW with a leaf-level biochemical photosynthesis model. The SHAW model provides leaf water potential to the photosynthesis model to calculate intercellular CO 2 (C) through stomatal control in each layer within the canopy, and solar radiation, air temperature and humidity to calculate photosynthetic rate (Pa) within each canopy layer. Stomatal conductance (g) was calculated by a revised Ball-Berry model, which describes the relationship between g and P and was a feedback from the photosynthesis model to SHAW to calculate energy and water transfer and in turn the leaf water potential. The photosynthesis model was run iteratively with the SHAW leaf energy balance within each canopy layer to reach convergence in leaf temperature. After including the relationship between stomatal conductance and photosynthetic rate, computed stomatal conductance in the extended SHAW (SHAW-Pn) model was able to respond to the variation of CO2 concentration. Validation of the photosynthesis model showed adequate simulations of responses of photosynthesis, transpiration, stomatal conductance, and C, at leaf level to changes in light and CO 2. The SHAW-Pn performed excellently in simulating net radiation, sensible and latent heat, and CO 2 fluxes over a winter wheat field in the North China Plain (36°57'N, 11636'E, 28 m above sea level). The root mean square error (RMSE) of the simulation for net radiation, latent, and sensible heat fluxes was 36.1, 31.0, and 25.8 W m 2, respectively. The RMSE of CO 2 flux simulation was 0.18 mg rn s'. SHAW-Pn describes the biophysico-chemical processes and water and carbon cycles in the ecosystem, which can be a framework of vegetation response to atmospheric CO 2 changes but needs incorporation of a detailed plant growth module.

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Section: Stomatal Modelsmentioning

confidence: 99%

Section: Flux Measurementmentioning

confidence: 99%

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Extending the Simultaneous Heat and Water (SHAW) Model to Simulate Carbon Dioxide and Water Fluxes over Wheat Canopy

Flerchinger

2015

Response of Crops to Limited Water

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“…Detailed descriptions of parameters and validation of the equation were given by Yu et al (2007). The main input data of the model included air temperature, water vapour pressure, wind speed, net radiation, soil heat flux, surface soil water content, averaged soil temperature at 0Á10 cm depth, leaf area index and crop height.…”

Section: Coupled Photosynthesis and Transpiration Modelmentioning

confidence: 99%

Measurement and simulation of diurnal variations in water use efficiency and radiation use efficiency in an irrigated wheat-maize field in the North China Plain

Wang

Zhao

Wang

et al. 2010

New Zealand Journal of Crop and Horticultural Science

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Quantifying diurnal patterns of water use efficiency (WUE) and radiation use efficiency (RUE) for wheat and maize is important for assessing water use by plants and crop productivity. Water and carbon dioxide fluxes from an irrigated wheat-maize double-crop field from November 2002 to October 2003 were measured using the Eddy Covariance method. Evident differences were observed between the diurnal patterns of WUE for wheat and maize. The WUE values of wheat peaked near 9, 15 and 12 mg CO 2 g H 2 O in the morning, and then decreased linearly with time and recovered in the late afternoon (4:00pm) before sunset in March, April and May, respectively. The WUE of maize increased after sunrise and retained stable values of 6, 14 and 12 mg CO 2 g H 2 O from mid-morning to mid-afternoon (10:00am Á2:00pm) and then decreased slowly with time until sunset in July, August and September, respectively. Similar patterns were observed in the RUE of wheat and maize. Over the three months of the study, averaged RUE was 1.76 g C MJ(1 for the wheat crop and 1.87 g C MJ (1 for the maize crop. A coupled photosynthesis and transpiration model was used to simulate the diurnal variations in WUE under variable climate conditions. Measurement results and sensitivity analysis show that the difference in the diurnal variation pattern in WUE between wheat and maize resulted from the different carbon fixing mechanisms of wheat and maize.

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“…Collatz et al (1991), Leuning (1995) and Yu et al (2002) calculated stomatal conductance by coupling transpiration and photosynthesis. More recently, Tuzet et al (2003) and Yu et al (2007), among many others, also take the effect of leaf water potential into account. These stomatal conductance models at leaf scale can be used to determine canopy resistance by up-scaling based on appropriate approaches (De Pury and Faquhar, 1997;Cox et al, 1998).…”

Section: Introductionmentioning

confidence: 99%

A simple method using climatic variables to estimate canopy temperature, sensible and latent heat fluxes in a winter wheat field on the North China Plain

Su³

et al. 2008

Hydrological Processes

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Abstract:Estimation of evapotranspiration from a crop field is of great importance for detecting crop water status and proper irrigation scheduling. The Penman-Monteith equation is widely viewed as the best method to estimate evapotranspiration but it requires canopy resistance, which is very difficult to determine in practice. This paper presents a simple method simplified from the Penman-Monteith equation for estimating canopy temperature (T c ). The proposed method is a biophysically-sound extended version of that proposed by Todorovic. The estimated canopy temperature is used to calculate sensible heat flux, and then latent heat flux is calculated as the residual of the surface energy balance. An eddy covariance (EC) system and an infrared thermometer (IRT) were installed in an irrigated winter wheat field on the North China Plain in 2004 and 2005, to measure T c , and sensible and latent heat fluxes were used to test the modified Todorovic model (MTD). The results indicate that the original Todorovic model (TD) severely underestimates T c and sensible heat flux, and hence severely overestimates the latent heat flux. However, the MTD model has good capability for estimating T c , and gives acceptable results for latent heat flux at both half-hourly and daily scales. The MTD model results also agreed well with the evapotranspiration calculated from the measured T c .

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Influence of leaf water potential on diurnal changes in CO2 and water vapour fluxes

Cited by 11 publications

References 52 publications

Extending the Simultaneous Heat and Water (SHAW) Model to Simulate Carbon Dioxide and Water Fluxes over Wheat Canopy

Extending the Simultaneous Heat and Water (SHAW) Model to Simulate Carbon Dioxide and Water Fluxes over Wheat Canopy

Measurement and simulation of diurnal variations in water use efficiency and radiation use efficiency in an irrigated wheat-maize field in the North China Plain

A simple method using climatic variables to estimate canopy temperature, sensible and latent heat fluxes in a winter wheat field on the North China Plain

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