Articles
Evaluation of plant light usage efficiency in controlled environment agriculture (CEA)
Article number
1425_51
Pages
397 – 402
Language
English
Abstract
Light is the one of the driving forces of photosynthesis and an important necessity for optimal plant growth in controlled environment agriculture (CEA). Since light emitting diodes (LED) were introduced for horticultural illumination, research was focused on light spectrum manipulation.
However, for practical application, light intensity, expressed as photosynthetic photon flux density (PPFD) is of topical importance, as it determines the main electricity expenses.
Therefore, our objective was to empirically evaluate photon use efficiency in different light PPFD treatments and explore number-based recommendations of optimal PAR selection for different plant species.
In this study, leafy vegetables: lettuce, purslane, perilla, amaranth and ice plant were cultivated in deep water culture hydroponics systems in walk-in controlled environment growth chamber (maintaining 21/17°C night/day temperature, 16-h photoperiod, 1000 ppm CO2 and 55% RH) at PPFDs of 150, 200, 250 and 300 µmol m‑2 s‑1 (daily light integral of DLI = 8.6, 11.5, 14.4 and 17.3 mol m‑2 day‑1, respectively), while equal light spectrum proportions (deep red 61%, blue 20%, white 15% and far red 4%) were maintained.
At maturity stage, plant biomass and photosynthetic productivity were evaluated.
A derivative parameter, calculated as the ratio of Δ fresh mass (%) and Δ DLI (%) is proposed to model and compare light usage efficiency for biomass accumulation between different PPFD treatments in leafy vegetables of different morphology.
Holistic view is introduced for the synergy of research knowledge for practical applications in CEA.
However, for practical application, light intensity, expressed as photosynthetic photon flux density (PPFD) is of topical importance, as it determines the main electricity expenses.
Therefore, our objective was to empirically evaluate photon use efficiency in different light PPFD treatments and explore number-based recommendations of optimal PAR selection for different plant species.
In this study, leafy vegetables: lettuce, purslane, perilla, amaranth and ice plant were cultivated in deep water culture hydroponics systems in walk-in controlled environment growth chamber (maintaining 21/17°C night/day temperature, 16-h photoperiod, 1000 ppm CO2 and 55% RH) at PPFDs of 150, 200, 250 and 300 µmol m‑2 s‑1 (daily light integral of DLI = 8.6, 11.5, 14.4 and 17.3 mol m‑2 day‑1, respectively), while equal light spectrum proportions (deep red 61%, blue 20%, white 15% and far red 4%) were maintained.
At maturity stage, plant biomass and photosynthetic productivity were evaluated.
A derivative parameter, calculated as the ratio of Δ fresh mass (%) and Δ DLI (%) is proposed to model and compare light usage efficiency for biomass accumulation between different PPFD treatments in leafy vegetables of different morphology.
Holistic view is introduced for the synergy of research knowledge for practical applications in CEA.
Authors
G. Kudirka, A. Virilė, K. Lauikė, G. Samuolienė
Keywords
hydroponics, protected crops, light emitting diodes, photosynthetic photon flux density, leafy vegetables
Groups involved
- Division Plant-Environment Interactions in Field Systems
- Division Precision Horticulture and Engineering
- Working Group Modelling in Fruit Research and Orchard Management
- Working Group Modelling Plant Growth, Environmental Control, Greenhouse Environment
- Division Greenhouse and Indoor Production Horticulture
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