Articles
Measurement of the CO2 exchange of a tomato canopy inside an Almería type naturally ventilated greenhouse
Article number
1296_9
Pages
65 – 72
Language
English
Abstract
This work analyses the whole-canopy gas exchange of CO2 inside a naturally ventilated greenhouse.
The objective of this work was to estimate the photosynthesis of a tomato crop.
The experiments were carried out in a five-span Almería-type greenhouse with a structure raspa y amagado with a floor area of 1922 m2, equipped with three roof vents and side openings.
Experimental data were recorded on four non-consecutive days of May 2018. Air velocity in all vents was measured using 8 wind sonic 2D anemometers (located in the middle of the vents) and two 3D sonic anemometers (moving at four locations along the side openings). Additionally, an IRGASON systems (integrating an open-path analyser and a 3D sonic anemometer) was used to measure simultaneously air velocity and CO2 mass density in the roof openings.
The volumetric flow rate through the greenhouse was calculated from the perpendicular component of the air velocity to the opening plane.
CO2 flux in the greenhouse was obtained multiplying the volumetric flow by the differences in CO2 concentration between air exiting and entering through the openings.
These values were compared to the uptake of CO2 of a tomato crop estimated from photosynthetic activity measured at leaves with a portable sensor.
Ventilation flow rate per unit floor area ranged from 0.008 to 0.041 m3 s‑1 m‑2, in function of the wind direction and speed (from 2.8 to 10.1 m s‑1). Differences between CO2 concentration of air entering and exiting the greenhouse through the openings varied with the wind speed, from 8.5 to 54.8 mg CO2 m‑3. The CO2 uptake by the crop calculated from photosynthetic activity measured at leaves ranged between 2.9 and 5.4 kg ha‑1 h‑1. Estimation from ventilation flow (7.6 and 19.8 kg ha‑1 h‑1) overestimate largely these values.
The objective of this work was to estimate the photosynthesis of a tomato crop.
The experiments were carried out in a five-span Almería-type greenhouse with a structure raspa y amagado with a floor area of 1922 m2, equipped with three roof vents and side openings.
Experimental data were recorded on four non-consecutive days of May 2018. Air velocity in all vents was measured using 8 wind sonic 2D anemometers (located in the middle of the vents) and two 3D sonic anemometers (moving at four locations along the side openings). Additionally, an IRGASON systems (integrating an open-path analyser and a 3D sonic anemometer) was used to measure simultaneously air velocity and CO2 mass density in the roof openings.
The volumetric flow rate through the greenhouse was calculated from the perpendicular component of the air velocity to the opening plane.
CO2 flux in the greenhouse was obtained multiplying the volumetric flow by the differences in CO2 concentration between air exiting and entering through the openings.
These values were compared to the uptake of CO2 of a tomato crop estimated from photosynthetic activity measured at leaves with a portable sensor.
Ventilation flow rate per unit floor area ranged from 0.008 to 0.041 m3 s‑1 m‑2, in function of the wind direction and speed (from 2.8 to 10.1 m s‑1). Differences between CO2 concentration of air entering and exiting the greenhouse through the openings varied with the wind speed, from 8.5 to 54.8 mg CO2 m‑3. The CO2 uptake by the crop calculated from photosynthetic activity measured at leaves ranged between 2.9 and 5.4 kg ha‑1 h‑1. Estimation from ventilation flow (7.6 and 19.8 kg ha‑1 h‑1) overestimate largely these values.
Publication
Authors
F.D. Molina-Aiz, A. López, D.L. Valera, T. Zormati, H. Najjari, Y. Boussoffara
Keywords
greenhouse, ventilation, airflow, photosynthesis, sonic anemometry
Groups involved
- Division Precision Horticulture and Engineering
- Division Greenhouse and Indoor Production Horticulture
- Working Group Organic Greenhouse Horticulture
- Working Group Protected Cultivation, Nettings and Screens for Mild Climates
- Working Group Light in Horticulture
- Working Group Vegetable Grafting
- Working Group Computational Fluid Dynamics in Agriculture
- Working Group Mechanization, Digitization, Sensing and Robotics
- Working Group Modelling Plant Growth, Environmental Control, Greenhouse Environment
- Working Group Greenhouse Environment and Climate Control
- Working Group Design and Automation in Integrated Indoor Production Systems
- Commission Agroecology and Organic Farming Systems
- Division Landscape and Urban Horticulture
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