Free-air CO2 enrichment effects on the energy balance and evapotranspiration of sorghum

Triggs, J.; Kimball, Bruce A.; Pinter, P. J.; Wall, Gerard W.; Conley, Matthew M.; Brooks, T. J.; LaMorte, R. L.; Adam, Neal R.; Ottman, Michael J.; Matthias, A. D.; Leavitt, Steven W.; Cerveny, Randall S.

doi:10.1016/j.agrformet.2004.01.005

Cited by 79 publications

(76 citation statements)

References 42 publications

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“…In another study, Li et al (2004) reported that the CO 2 enrichment-induced decrease in transpiration almost compensated for the increase in transpiration brought by the higher leaf area. Similar findings were reported in a number of studies (Mauney et al, 1994, Kimbal et al, 1999, 2002Triggs et al, (2004)) stating that crops with large growth responses to elevated CO 2 had near zero water savings while crops with modest growth responses had a water savings of about 7%. This has energy consequences as well.…”

Section: Resultssupporting

confidence: 75%

Simulated Effects of Various Environmental Management Practices on Energy Consumption in Open and Confined Greenhouse Systems

Yildiz¹,

Stombaugh²

2008

Acta Hortic.

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The objective of this study was to evaluate the effects of relative humidity, light management levels, minimum ventilation rates, CO 2 enrichment and canopy size on energy consumption in three different greenhouse systems (conventional, open-loop heat pump, and confined heat pump) in winter, spring, and summer months. No difference was observed in energy consumption with relative humidity set point levels in winter due to the already low relative humidity levels. Some differences were observed in spring and summer due to extra dehumidification required to maintain the inside relative humidity at lower levels. Energy consumption in summer was reduced up to 25.5% by using an 80% relative humidity set point instead of 70% in the open heat pump system. Using a 250 W/m 2 light management level instead of 350 W/m 2 resulted in a 5% reduction in energy consumption in summer, but the energy used for ventilation and heating did not change in summer. The only change was observed in the energy required for cooling. However, the energy consumption was significantly affected by the minimum ventilation rate. A 50% reduction (using 0.005 m 3 /s.m 2 instead of 0.01 m 3 /s.m 2 ) in the minimum ventilation rate resulted in 26%, 21%, and 1.5% decreases in total energy consumptions in winter, spring, and summer, respectively. Using a CO 2 enrichment level of 1000 ppm compared to an enrichment level of 350 ppm resulted in a slight decrease in leaf temperatures during the day. This decrease caused a decrease in the air temperature resulting in slightly higher energy consumption for heating the greenhouse. This small increase in the energy consumption was about 1.7%. The partial canopy (0.4 m) systems had more energy consumption than the full canopy (2.0 m) greenhouse systems. INTRODUCTIONTo provide economically optimal micro-environments for plant growth, producers can use or control the number of glazing layers, insulation curtains or screens to reduce long-wave radiation losses at night, reduced ventilation rates, evaporative coolers, and shading devices to control incoming solar radiation. In addition, a Rankine cycle heat pump that was developed by Yildiz (1993), andYildiz et al. (1993) holds promise for reducing winter heating requirements and warm weather cooling loads. These systems involve complex tradeoffs between initial and operating costs for cooling and heating, plant responses to various environmental factors and the strategies used to regulate temperature, humidity and CO 2 levels in the crop canopy. Special attention must also be given to the operational strategies associated with the use of heat pumps, especially in maintaining acceptable relative humidity levels within greenhouses.A dynamic simulation model was developed and validated to provide an accurate prediction of greenhouse energy and moisture exchanges as a function of dynamic environmental factors (Yildiz and Stombaugh, 2006). This model was used to predict heating and cooling loads, and to evaluate the operational strategies associated with heatin...

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Section: Resultssupporting

confidence: 75%

Simulated Effects of Various Environmental Management Practices on Energy Consumption in Open and Confined Greenhouse Systems

Yildiz¹,

Stombaugh²

2008

Acta Hortic.

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“…During the dry-down, C i /C a steadily decreased, so that A T /E T increased, which is consistent with published studies where non-stomatal limitations to carbon uptake are minimal (Brodribb, 1996). Midday leaf water potential ( L ) decreased steadily, as typically observed (Sperry, 2000), and leaf temperature increased as a result of lower stomatal conductance in dry soil (Jones, 1992;Triggs et al, 2004). Finally, the depth of root water uptake gradually shifted to deeper layers (cf.…”

Section: Understanding Controls On the C A × Drought Interactionsupporting

confidence: 88%

MAESPA: a model to study interactions between water limitation, environmental drivers and vegetation function at tree and stand levels, with an example application to [CO<sub>2</sub>] × drought interactions

2012

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Abstract.Process-based models (PBMs) of vegetation function can be used to interpret and integrate experimental results. Water limitation to plant carbon uptake is a highly uncertain process in the context of environmental change, and many experiments have been carried out that study drought limitations to vegetation function at spatial scales from seedlings to entire canopies. What is lacking in the synthesis of these experiments is a quantitative tool incorporating a detailed mechanistic representation of the water balance that can be used to integrate and analyse experimental results at scales of both the whole-plant and the forest canopy. To fill this gap, we developed an individual treebased model (MAESPA), largely based on combining the well-known MAESTRA and SPA ecosystem models. The model includes a hydraulically-based model of stomatal conductance, root water uptake routines, drainage, infiltration, runoff and canopy interception, as well as detailed radiation interception and leaf physiology routines from the MAES-TRA model. The model can be applied both to single plants of arbitrary size and shape, as well as stands of trees. The utility of this model is demonstrated by studying the interaction between elevated [CO 2 ] (eC a ) and drought. Based on theory, this interaction is generally expected to be positive, so that plants growing in eC a should be less susceptible to drought. Experimental results, however, are varied. We apply the model to a previously published experiment on droughted cherry, and show that changes in plant parameters due to long-term growth at eC a (acclimation) may strongly affect the outcome of C a × drought experiments. We discuss potential applications of MAESPA and some of the key uncertainties in process representation.

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“…Numerous previous studies have used the REB method for maize and sorghum agroecosystems (Kimball et al, 1994;Triggs et al, 2004;Hickman et al, 2010;Hussain et al, 2013). Previous studies (Kimball et al, 1994;Triggs et al, 2004;Bernacchi et al, 2007;VanLoocke et al, 2012a) have demonstrated that the REB method is appropriate for plots of relatively small fetch, since the implementation of radiometric temperature in aerodynamic resistance equations reduces fetch requirements compared to other micrometeorological methods (Kimball et al, 1994). In the REB method, net flux divergence due to advection, photosynthesis, respiration, and canopy storage are assumed to be negligible (Meyers & Hollinger, 2004).…”

Section: Micrometeorologymentioning

confidence: 99%

Biomass sorghum and maize have similar water-use-efficiency under non-drought conditions in the rain-fed Midwest U.S.

Roby

Fernandez

Heaton

et al. 2017

Agricultural and Forest Meteorology

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Free-air CO2 enrichment effects on the energy balance and evapotranspiration of sorghum

Cited by 79 publications

References 42 publications

Simulated Effects of Various Environmental Management Practices on Energy Consumption in Open and Confined Greenhouse Systems

Simulated Effects of Various Environmental Management Practices on Energy Consumption in Open and Confined Greenhouse Systems

MAESPA: a model to study interactions between water limitation, environmental drivers and vegetation function at tree and stand levels, with an example application to [CO<sub>2</sub>] × drought interactions

Biomass sorghum and maize have similar water-use-efficiency under non-drought conditions in the rain-fed Midwest U.S.

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Free-air CO2 enrichment effects on the energy balance and evapotranspiration of sorghum

Cited by 79 publications

References 42 publications

Simulated Effects of Various Environmental Management Practices on Energy Consumption in Open and Confined Greenhouse Systems

Simulated Effects of Various Environmental Management Practices on Energy Consumption in Open and Confined Greenhouse Systems

MAESPA: a model to study interactions between water limitation, environmental drivers and vegetation function at tree and stand levels, with an example application to [CO&lt;sub&gt;2&lt;/sub&gt;] × drought interactions

Biomass sorghum and maize have similar water-use-efficiency under non-drought conditions in the rain-fed Midwest U.S.

Contact Info

Product

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MAESPA: a model to study interactions between water limitation, environmental drivers and vegetation function at tree and stand levels, with an example application to [CO<sub>2</sub>] × drought interactions