Articles
Management of far-red fraction to improve lettuce yield and light use efficiency in vertical farm cultivation
Article number
1441_5
Pages
35 – 42
Language
English
Abstract
In vertical farms and indoor farming systems, precise light management represents an opportunity to enhance growth and light use efficiency (LUE) while controlling plant morphology and quality.
Red (R; 600-700 nm) and blue (B; 400-500 nm) are among the most used spectral regions in controlled environment agriculture.
However, providing plants with far-red radiation (FR; 700-750 nm), in combination with shorter wavelengths (400-700 nm), triggers a series of morphological and physiological responses that could be beneficial for crop growth.
The aim of this study was to construct dose-response curves with different intensities of FR radiation, in order to accurately analyse the response in terms of yield, morphology and light use efficiency for lettuce cultivation.
Lettuce plants (Lactuca sativa ‘Canasta’) were grown in an ebb-and-flow system for 29 days.
During the cycle, plants were subjected to 5 different light treatments, including a control treatment composed of an optimized R and B spectrum (ratio of R and B of 3, RB3), with a photosynthetic photon flux density (PPFD) of 200 µmol m‑2 s‑1, and four treatments in which 12, 35, 66 and 100 µmol m‑2 s‑1 of FR radiation have been added to RB3 (namely RB3+12, RB3+35, RB3+66 and RB3+100, respectively). In all light treatments, the PPFD and photoperiod were kept constant.
At final harvest, plants grown with RB3+35, RB3+66 and RB3+100 had the highest leaf fresh and dry weights (LFW and LDW, respectively), as well as the greatest leaf area.
While no differences were found in terms of lighting energy use efficiency (L-EUE, expressed as g LFW kWh‑1) between the treatments, RB3+100 decreased light use efficiency (LUE, considered as the ratio between LDW and the moles of light in the spectrum range 400-750 nm), compared to RB3+35. The adoption of the lighting treatments enriched with 35 to 66 µmol m‑2 s‑1 of FR radiation is therefore a valid strategy to increase yield and LUE for lettuce cultivation in a vertical farm.
Red (R; 600-700 nm) and blue (B; 400-500 nm) are among the most used spectral regions in controlled environment agriculture.
However, providing plants with far-red radiation (FR; 700-750 nm), in combination with shorter wavelengths (400-700 nm), triggers a series of morphological and physiological responses that could be beneficial for crop growth.
The aim of this study was to construct dose-response curves with different intensities of FR radiation, in order to accurately analyse the response in terms of yield, morphology and light use efficiency for lettuce cultivation.
Lettuce plants (Lactuca sativa ‘Canasta’) were grown in an ebb-and-flow system for 29 days.
During the cycle, plants were subjected to 5 different light treatments, including a control treatment composed of an optimized R and B spectrum (ratio of R and B of 3, RB3), with a photosynthetic photon flux density (PPFD) of 200 µmol m‑2 s‑1, and four treatments in which 12, 35, 66 and 100 µmol m‑2 s‑1 of FR radiation have been added to RB3 (namely RB3+12, RB3+35, RB3+66 and RB3+100, respectively). In all light treatments, the PPFD and photoperiod were kept constant.
At final harvest, plants grown with RB3+35, RB3+66 and RB3+100 had the highest leaf fresh and dry weights (LFW and LDW, respectively), as well as the greatest leaf area.
While no differences were found in terms of lighting energy use efficiency (L-EUE, expressed as g LFW kWh‑1) between the treatments, RB3+100 decreased light use efficiency (LUE, considered as the ratio between LDW and the moles of light in the spectrum range 400-750 nm), compared to RB3+35. The adoption of the lighting treatments enriched with 35 to 66 µmol m‑2 s‑1 of FR radiation is therefore a valid strategy to increase yield and LUE for lettuce cultivation in a vertical farm.
Publication
Authors
L. Carotti, I. Zauli, A. Pistillo, G. Gianquinto, G. Pennisi, F. Orsini
Keywords
LED lighting, plant factories with artificial lighting (PFALs), far-red radiation, ebb and flow
Groups involved
- Division Landscape and Urban Horticulture
- Division Greenhouse and Indoor Production Horticulture
- Division Precision Horticulture and Engineering
- Division Plant-Environment Interactions in Field Systems
- Division Horticulture for Human Health
- Division Vegetables, Roots and Tubers
- Working Group Vertical Farming
- Working Group Urban Horticulture
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