Vine crops, specifically tomatoes, are one of the most heavily produced and consumed crops in the world. As such, tomato cultivation also represents one of the largest market segments for greenhouse growing. Since greenhouses are one of the most resource, labor, energy and yield efficient ways growers have found to cultivate crops, greenhouses also represent a key area of research for the future of horticulture.
Since the 19th century, many factors of greenhouse cultivation have been solved in The Netherlands, due in part to the leadership of Wageningen, the #1 agricultural sciences university and research center in the world. Which is why scientists at Fluence by OSRAM are collaborating with Wageningen to explore the use of full-spectrum LEDs as supplemental lighting in greenhouses. Legacy HID technologies have been used to much commercial success for decades but have also equated into high operational expenditure costs. The relatively recent introduction of narrow-band LEDs into horticulture has introduced efficiencies into the industry, and the effects of each band of spectrum are being researched and leveraged commercially, but a solid base of foundational research around the effects of a full compilation of spectra is still lacking in scientific literature.
Results from a two-factor experiment, comparing the influence of light quality and temperate on two common tomato cultivars (Tomagino and Merlice) analyzed at Wageningen, in collaboration with Fluence and Vortus bv (a leading greenhouse consulting firm), has produced promising results which prove the viability of full spectrum LEDs in greenhouses (see figure 1). The experiment, which considered temperature, light quality of PhysioSpec Greenhouse (table 1), HPS and an experimental spectrum, has produced data which shows a difference in yield.
|Species, cultivar: Merlice, Tomagino|
|Compartment #1||Compartment #2|
|Temperature||Day: 20-21 C |
Night: 16 C
|Day: 20-21 C
Night: 16 C
|Relative Humidity||57% ± 1.5%||57% ± 1.5%|
|[CO2] Setpoint||1000 ppm||1000 ppm|
|Fertigation Strategy||Standard Tomato Solution||Standard Tomato Solution|
|Supplemental Canopy Level PFD; 400-800nm||200µmol m-2 s-1||200µmol m-2 s-1|
|Light Spectra||1) 600 W HPS |
2) PhysioSpec Greenhouse
|1) PhysioSpec Greenhouse
2) PhysioSpec Greenhouse Far Red
The preliminary data comparing tomato yield under PhysioSpec Greenhouse to HPS shows Tomagino crops under PhysioSpec Greenhouse yielded more fresh fruit. Increasing the temperature for PhysioSpec Greenhouse treated plants by 1 degree Celsius made the yield difference even more pronounced, increasing the difference from an average 3% greater versus HPS, to an average of 11%, (figure 2a). The data for Merlice also showed promising results, yielding comparable amounts of fresh fruit between treatments, further proving full spectrum LEDs as viable replacement for HPS in greenhouse tomato production.
Yield Increase under PhysioSpec Greenhouse 11% vs. HPS
The research at Wageningen shows promise for the viability of LEDs in terms of yield, with the added benefit of being more energy efficient than legacy lighting solutions common to greenhouse production today. “The initial results of this trial show growers can cultivate tomatoes as effectively with PhysioSpec Greenhouse as you can under HPS, possibly with a better yield, and with shorter stems,” said Dr. Ep Heuvelink, associate professor, WUR.
Additionally, the director of Vortus, Barend Löbker, said ““Current practices use HPS technology as the sole source for supplemental lighting in greenhouses and the WUR trial proves this should not be the case. Growers have been reluctant to transition to LEDs because they are uncertain if LEDs can be as effective for cultivation and the WUR trial eliminates any doubts around the capabilities of full spectrum LEDs.”
Fluence plans to continue to work with Wageningen to compare ongoing research with this trial and conduct more research around full spectrum and narrow band LEDs, as well as additional types of crops. Our senior photobiologist, Haris Ouzounis, will oversee these studies with Wageningen and has stated, “Upcoming studies from Fluence into the influences of light quality, distribution, and intensity, as well as optimizations to the rest of the environment should demonstrate improvements in productivity compared to legacy production practices.”
Research is of paramount importance at Fluence as it helps direct what technologies will have the most impact on how cultivation solutions should be deployed in the industry. Fluence is proud to have joined the Wageningen Club of 100 to further research with the esteemed university, in addition to the other global initiatives we have in place with other organizations such as the Foundation for Food and Agricultural Research, University of Florida, University of Utah, and many other private businesses and public organizations around the world.
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