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Transpiration of greenhouse crops : an aid to climate management
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In this paper, physical aspects of greenhouse climate are analyzed to show the direct interrelation between microclimate and crop transpiration, and it is shown that defining the transpiration rate as the criterion for the control of air humidity within a greenhouse would deliver a quantitative framework for that control.Abstract:
In this book some physical aspects of greenhouse climate are analyzed to show the direct interrelation between microclimate and crop transpiration. The energy balance of a greenhouse crop is shown to provide a sound physical framework to quantify the impact of microclimate on transpiration and to identify the constraints set on climate management by the termodynamic behaviour of the canopy. Before the relationship among microclimate, canopy temperature and transpiration is rendered in mathematical terms, a good deal of experimental work is necessary to establish sub-models for the heat transfer of the foliage, for the radiative transfer within the canopy and for the canopy resistance to vapour transfer. The sub-models are merged in a combination-type equation to obtain the temperature of a greenhouse crop and its transpiration. The resulting estimates are shown to reproduce accurately the temperature and transpiration of a greenhouse tomato crop, as measured at time intervals of a few minutes. To illustrate the practical application of the model thus developed a number of examples are presented. In particular, it is shown that defining the transpiration rate as the criterion for the control of air humidity within a greenhouse would deliver a quantitative framework for that control. That would largely enhance the efficiency of the (expensive) procedures applied at present for the control of humidity in greenhouses.read more
Citations
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The Theory of Hydrodynamic Stability
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Development and dry matter distribution in glasshouse tomato : a quantitative approach
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References
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Simulation of the Temperature, Humidity and Evaporation Profiles in a Leaf Canopy
TL;DR: In this paper, a model was proposed to synthesize profiles of temperature, humidity and evaporation in a canopy of leaves from meteorological conditions at canopy top, from the temperature and humidity at the soil surface, from a leaf dimension, from vertical distribution of leaf area and stomatal resistance, and from observations or extinction coefficients for ventilation and radiation within the canopy under steady-state conditions.
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The exchange of momentum, mass, and heat between an artificial leaf and the airflow in a wind-tunnel
TL;DR: In this paper, the authors investigated the relationship between the skin friction part of the drag on a natural surface and a simultaneous transfer of mass or heat, and measured the dimensionless transfer coefficients Cd, Cv and Ch for the exchange of (streamwise) momentum, mass, and heat, between a single artificial leaf and the airflow in a wind-tunnel.
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Convective Cooling at Low Airspeeds and the Shapes of Broad Leaves
TL;DR: In this article, surface temperature distributions of flat copper plates were matched to those of real leaves in a very low-speed wind tunnel, and they were measured at wind velocities of < 1, 10, and 30 cm s_1 from below and laterally with horizontal and vertical plate orientations.
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The measurement and control of stomatal resistance in the field
TL;DR: Measurements in a field of barley support the hypothesis that rs is the diffusion resistance of the complete crop canopy, and the increase of rs calculated from the decrease of transpiration rate was consistent with the change of rp.
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The influence of light on stomatal density in the tomato
TL;DR: Stomatal initiation and stomatal density both decreased from then until leaf expansion ceased, and fully-expanded leaves of plants grown continuously in the same environment had similar Stomatal densities irrespective of their position on the plant.