Articles
Supplemental light quality, control, and CO2 strategies impact strawberry yield and quality
Article number
1423_38
Pages
301 – 308
Language
English
Abstract
Horticultural light-emitting diodes (LEDs) enable improved energy efficiency and control relative to conventional high-pressure sodium (HPS) lighting.
Carbon dioxide (CO2) enrichment also increases plant biomass and yield for several high-value horticultural crops.
This study evaluated greenhouse strawberries using a Cornell University-developed lighting control algorithm, light and shade system implementation (LASSI), which controls light and shade curtains to target a consistent daily light integral (DLI). The first experiment compared supplemental LED lighting with near real-time dimming (10-min intervals) to a target PPFD (RT-LASSI) to conventional HPS lighting treatments with on/off control (LASSI) without CO2 supplementation.
The second experiment compared strawberry yield and quality using LED lighting with RT-LASSI combined with CO2 enrichment (CO2-RT-LASSI) to a conventional HPS lighting treatment with on/off control (LASSI). In the first experiment, strawberry cultivars ‘Albion’ and ‘Cabrillo’ were grown in a climate-controlled glass greenhouse with a target DLI of 20 mol m‑2 d‑1. Both the LED and HPS treatments were successful in reaching the target DLI, but the LED treatment received approximately 0.32 mol m‑2 s‑1 or 2% less PAR relative to the HPS treatment.
The LED RT-LASSI ‘Albion’ treatment resulted in statistically similar marketable fresh fruit biomass with generally equal fruit quality (Brix and titratable acidity) compared to the control ‘Albion’ treatment (LASSI). The LED RT-LASSI ‘Cabrillo’ treatment also had statistically similar but a numerically 5% greater fresh fruit biomass with generally equal fruit quality compared to the control ‘Cabrillo’ treatment.
The second experiment only used ‘Albion’ and added CO2 enrichment to the RT-LASSI treatment to achieve the same target virtual DLI as the HPS control.
Because the experiment was conducted in late spring, the average CO2 concentration in the CO2-RT-LASSI treatment was 555 µmol mol‑1. CO2-RT-LASSI treatment had 29% greater fruit yield plant‑1, even with an 11% lower DLI than their HPS LASSI counterparts.
However, HPS LASSI resulted in a 9% Brix content increase, suggesting a potential trade-off between fruit yield and sweetness.
CO2-RT-LASSI provided about 41% energy savings (33% from LED energy efficiency and 8% based on reduced lighting needs from CO2 enrichment). More research is required to replicate findings and better understand the impact of the light spectrum and control strategy on strawberry yield and quality.
Carbon dioxide (CO2) enrichment also increases plant biomass and yield for several high-value horticultural crops.
This study evaluated greenhouse strawberries using a Cornell University-developed lighting control algorithm, light and shade system implementation (LASSI), which controls light and shade curtains to target a consistent daily light integral (DLI). The first experiment compared supplemental LED lighting with near real-time dimming (10-min intervals) to a target PPFD (RT-LASSI) to conventional HPS lighting treatments with on/off control (LASSI) without CO2 supplementation.
The second experiment compared strawberry yield and quality using LED lighting with RT-LASSI combined with CO2 enrichment (CO2-RT-LASSI) to a conventional HPS lighting treatment with on/off control (LASSI). In the first experiment, strawberry cultivars ‘Albion’ and ‘Cabrillo’ were grown in a climate-controlled glass greenhouse with a target DLI of 20 mol m‑2 d‑1. Both the LED and HPS treatments were successful in reaching the target DLI, but the LED treatment received approximately 0.32 mol m‑2 s‑1 or 2% less PAR relative to the HPS treatment.
The LED RT-LASSI ‘Albion’ treatment resulted in statistically similar marketable fresh fruit biomass with generally equal fruit quality (Brix and titratable acidity) compared to the control ‘Albion’ treatment (LASSI). The LED RT-LASSI ‘Cabrillo’ treatment also had statistically similar but a numerically 5% greater fresh fruit biomass with generally equal fruit quality compared to the control ‘Cabrillo’ treatment.
The second experiment only used ‘Albion’ and added CO2 enrichment to the RT-LASSI treatment to achieve the same target virtual DLI as the HPS control.
Because the experiment was conducted in late spring, the average CO2 concentration in the CO2-RT-LASSI treatment was 555 µmol mol‑1. CO2-RT-LASSI treatment had 29% greater fruit yield plant‑1, even with an 11% lower DLI than their HPS LASSI counterparts.
However, HPS LASSI resulted in a 9% Brix content increase, suggesting a potential trade-off between fruit yield and sweetness.
CO2-RT-LASSI provided about 41% energy savings (33% from LED energy efficiency and 8% based on reduced lighting needs from CO2 enrichment). More research is required to replicate findings and better understand the impact of the light spectrum and control strategy on strawberry yield and quality.
Authors
C.P. Levine, N. Kaczmar, N.S. Mattson
Keywords
supplemental lighting, sunlight prediction, controlled environment agriculture, strawberries, dimmable lighting
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