of supplemental LED vegetable propagationleds.hrt.msu.edu/assets/Uploads/PowerPoints/LEDs-in-veg-prop.pdf · Applications of supplemental LED lighting in vegetable propagation ...

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Applications of supplemental LED pp pplighting in vegetable propagation

Chieri Kubota and Ricardo Hernández

The University of Arizona

SCRI LED Stakeholders Meeting (6/24/2014)

UA LED Research Objectives

1. To conduct research necessary for vegetable propagators to adopt LED lighting technologypropagators to adopt LED lighting technology– Light quality requirement for LED lighting

– Side‐by‐side comparison with the conventional HID lighting

– Testing new fixture designs and application methods

2. To explore new LED applications beneficial to p ppvegetable propagators– Low intensity applications of red and far‐red LEDs for controlling plant morphology

– Pulsed lighting

University of Arizona 2014, Not for Publication

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Phase I: Supplemental LED B:R photon flux ratios for vegetable transplants

• ObjectiveT t diff t l t l LED Bl R d h t– Test different supplemental LED Blue:Red photon flux ratios for growth and development of vegetable transplants.

• Hypothesis

– Vegetable seedlings respond different to B:R PF ratios under different solar DLI conditions.

Phase I: Materials & Methods

Testing different RED:BLUE ratios providing 55 μmol m‐2 s‐1 for 18 hours = 3.54 molm‐2 d‐1 of supplemental LED light.

100%

4%

96%

16%

84%

N

NO SUPPLEMENTAL

LIGHT

treatment treatment treatment control

Blue = 455 nm, Red = 661 nm

96% 84%

Tested under different DLIs• Controlling sun radiation by deploying different shade

cloths.


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Phase I: Materials & Methods

DRY MASS RESPONSE

Effects of supplemental LED light

Phase I: Results

Similar results for

0.45 0.5

0.55 0.6 0.65 0.7

ry m

ass (g)

DRY MASS RESPONSE

control LED supplement

P < 0.000126%

increase

P < 0.0001

48%

Similar results for Tomato ‘Komeett’, and Pepper ‘Fascinato’

0.2 0.25 0.3 0.35 0.4

High DLI Low DLI

Shoot dr

SOLAR DAILY LIGHT INTEGRAL

48% increase

Hernández, R., Kubota, C. (2014)


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CUCUMBER LEAF AREA RESPONSE High DLI

Effects of LED B:R PF ratios

Phase I: Results

Leaf area reduction 13%

0.017

0.018

0.019

0.02

0.021

0.022

area/plant (m

2 )

CUCUMBER LEAF AREA RESPONSE High DLI

Low DLI

P = 0.2138

reduction: 13%

Dry mass reduction: 12%

0.014

0.015

0.016

0 2 4 6 8 10 12 14 16 18

Leaf

Percent of blue light

P = 0.0163

Hernández, R., Kubota, C. (2014)

Conclusion Phase I

• LED supplemental lighting increased plant growth even under high DLI conditions.under high DLI conditions.

• 100% red supplemental LED lighting is preferred at the current LED efficiencies.

• Responses to LED light quality vary under different solar DLI.

• Responses to LED light quality are species specific.


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Phase II

• Objective

– Quantify plant responses of vegetable transplants grown side‐by‐side under LED and HPS supplemental lighting

– Compared electrical efficiencies between HPS and LED supplemental lighting

Materials & methods: treatments

Testing different lighting technologies providing 60 μmol m‐2 s‐1

for 18 hours = 3.9 molm‐2 d‐1 of supplemental light.pp g

100% 100%100%

TreatmentRed‐LED

TreatmentBlue‐LED

Treatment 600W HPS

53%42%

5%

Blue = 443 nm peakRed = 632 nm peak

42%


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Phase III: Materials & methods

Phase III: Results

Cucumber ‘Cumlaude’

P < 0.0001

22% 22%

Similar results for tomato

A

BB

for tomato‘Komeett’

Hernández, R., Kubota, C. In press


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Phase III Results: morphology

P < 0.0001

38%

100% blue HPS 100% red

Hernández, R., Kubota, C. In press

Phase III: Discussion

Tomato and cucumber plants had higher dry mass under the HPS treatment than the LED treatments.under the HPS treatment than the LED treatments.

Air T measured directly under the leaf was 1 ºC higher in

Higher leaf T in HPS than LED

Air T measured directly under the leaf was 1 C higher in the HPS treatment


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Phase III: energy consumption

66 % more66 % more

Greenhouse Engineering R. Aldrich

Aeral Power Consumption (W m‐2) Fixture Growing Efficiency (g kWh‐1)

Phase III: energy consumption

Lamp type and ballast

Input power (W)

Fixture efficiency (µmol·J-1)

Fixture photon emission rate (PER,

µmol·s-1)

UF MF Effective photons (EP,

µmol·s-1)

Number of fixtures per

hectare

Areal power consumption

(W·m-2)

Fixture growing

efficiency (g·kWh-1)

Blue-LEDs 43x 1.9 y 81.2z 1.00u 0.85u 69 8258 35 3.3 600W HPS 656 1.6 w 1075z 0.90v 0.90v 871 655 43 3.5 Red-LEDs 22x 1.7 y 37z 1.00u 0.85u 31 18124 39 3.0

z Values provided by the manufacturer. y Values provided by Nelson and Bugbee (2013) for red-LED (655 nm) and blue-LED (455 nm).

Fixture Growing Efficiency (g kWh )

p y g ( ) ( ) ( )x Calculated using fixture photon emission rate and fixture efficiency. Input power does not include fixture controller and cooling system. w Calculated using fixture photon emission rate and measured input power. v Reported for HPS lamps by Aldrich and Bartok (1994). u UF is a high value due to the directional nature of the emitted light, MF is 0.85 since LED lamp life is defined as the time to reach 70% of initial output and LED light output almost linearly declines over time (EERE, 2009).

Hernández, R., Kubota, C. unpublished (a)


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Phase II: Energy Consumption Conclusion

• At the current technology state, supplemental HPS lighting is more efficient than supplemental LED lighting as over‐head lighting for the production of tomato and vegetable transplants.

Phase II: Leaf Curling Index in bell peppers


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Greenhouse pepper varieties

Phase II: Leaf Curling Index

• Viper• PP0710• Orangela• Fascinato

Phase II: Leaf Curling Index

Supplemental Blue Supplemental HPS Supplemental red

Hernández, R., Kubota, C. unpublished (b)


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Phase III: R:B photon flux ratio sole‐source LEDs

ObjectivesObjectivesEvaluate LED technology for the production of vegetable transplants.

Find the optimal B:R Photon flux ratio for theFind the optimal B:R Photon flux ratio for the production of vegetable transplants using LEDs.

Phase III: Materials & Methods

Testing different RED:BLUE ratios providing 100 μmol m‐2 s‐1 for 18 hours = 6.48 molm‐2 d‐1 DLI.

• 0B‐100R• 10B‐90R• 20B‐28G‐52R

• 30B‐70R• 50B‐50R• 75B‐25R• 100B‐0R

Growing temperature: 25 ˚CCO2 concentration: Maintained at ambientRH: 40‐70%


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Phase III: Materials & Methods

Phase III: Cucumber R:B ratio Results

Percent blue


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P<0.0001

Hernández, R., Kubota, C. unpublished (c)


P<0.0001



14


P<0.0001


Phase III: Tomato R:B ratio Results

P<0.0001

Hernández, R., Kubota, C. unpublished (d)


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Si l l f

Chlorophylls

(McCree, 1972; Sager et al.,1988)

Single leaf

Si l l f

Canopy (LAI =3)

Chloroplast

http://en.wikipedia.org

Single leaf

(Paradiso et al., 2011)

Light quality effect on plant growth can be photosynthetic or

photomorphogenic.

Plant growth rate = Leaf photosynthetic ratep y

x Leaf area


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AcknowledgementsAcknowledgements

• Mark Kroggel (UA, CEAC)

• CCS, Inc. (Kyoto, Japan)

ORBITEC (WI USA)CEAC)

• Alex Dragotakes

• Neal Barto (UA, CEAC)

• Jose Pablo Santana

• ORBITEC (WI, USA)

• Bevo Farms

• USDA SCRI

Greensys 2011, Greece


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