Articles
Dynamic analysis of leaf and air temperatures in a greenhouse canopy: which measurement to use for greenhouse climate control?
Article number
1426_9
Pages
59 – 66
Language
English
Abstract
Currently, in medium tech passive tunnel and multi-span greenhouses, the measurements used in the greenhouse to manage the climate are generally taken at 1.5 m above ground level.
However, if the ventilation of the shelter of the sensors is insufficient, the measured temperature can differ greatly from the actual temperature, especially during the day in summer.
In addition, the climatic conditions at 1.50 m can be very different from those at the level of the canopy.
From a physiological point of view, it is the temperature of the leaves that plays a major role in the development of the plant.
Having an air temperature close to the leaf temperature and easy to measure would thus be relevant to better control the climate in medium tech greenhouse.
The proposed study is based on the comparison of leaf with air temperature measurements carried out at several levels in and above the canopy, in ventilated or unventilated shelters, or even with unsheltered sensors.
The experiment was carried out in tunnel greenhouses at the ASTREDHOR station in Brindas, France.
Results reveal that the air temperature measurements closest to those of the leaves are those measured with unsheltered sensors positioned inside the canopy, under the leaves and protected from direct solar radiation.
Typically for a Chrysanthemum production, during a sunny day with 600 W m‑2 radiation, the average difference between the leaf temperature and air temperatures inside the canopy is 1.6°C. It reaches 4.1°C when compared with the air temperature measured inside a ventilated box at 1.50 m.
This measurement could be integrated in algorithms of climate control of greenhouses, which would allow to bring a high tech climate control to medium tech greenhouses.
However, if the ventilation of the shelter of the sensors is insufficient, the measured temperature can differ greatly from the actual temperature, especially during the day in summer.
In addition, the climatic conditions at 1.50 m can be very different from those at the level of the canopy.
From a physiological point of view, it is the temperature of the leaves that plays a major role in the development of the plant.
Having an air temperature close to the leaf temperature and easy to measure would thus be relevant to better control the climate in medium tech greenhouse.
The proposed study is based on the comparison of leaf with air temperature measurements carried out at several levels in and above the canopy, in ventilated or unventilated shelters, or even with unsheltered sensors.
The experiment was carried out in tunnel greenhouses at the ASTREDHOR station in Brindas, France.
Results reveal that the air temperature measurements closest to those of the leaves are those measured with unsheltered sensors positioned inside the canopy, under the leaves and protected from direct solar radiation.
Typically for a Chrysanthemum production, during a sunny day with 600 W m‑2 radiation, the average difference between the leaf temperature and air temperatures inside the canopy is 1.6°C. It reaches 4.1°C when compared with the air temperature measured inside a ventilated box at 1.50 m.
This measurement could be integrated in algorithms of climate control of greenhouses, which would allow to bring a high tech climate control to medium tech greenhouses.
Publication
Authors
V. Stauffer, D. Vuillermet, E. Chantoiseau, C. Ducourouble, P.E. Bournet
Keywords
microclimate, sensor, ornamental crop, climate heterogeneity
Groups involved
- Division Precision Horticulture and Engineering
- Division Greenhouse and Indoor Production Horticulture
- Working Group Nettings in Horticulture (subgroup of Protected Cultivation in Mild Winter Climates)
- Working Group Light in Horticulture
- Working Group Organic Greenhouse Horticulture
- Working Group Vegetable Grafting
- Working Group Modelling Plant Growth, Environmental Control, Greenhouse Environment
- Working Group Protected Cultivation, Nettings and Screens for Mild Climates
- Working Group Computational Fluid Dynamics in Agriculture
- Working Group Design and Automation in Integrated Indoor Production Systems
- Working Group Mechanization, Digitization, Sensing and Robotics
- Working Group Greenhouse Environment and Climate Control
- Division Landscape and Urban Horticulture
- Commission Agroecology and Organic Farming Systems
- Division Vegetables, Roots and Tubers
- Working Group Vertical Farming
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