LED it be: controlling plant production by LED Light Prof Dr Leo Marcelis Chair group Horticulture & Product Physiology Wageningen University, Netherlands. Leo.Marcelis@wur.nl
Area (ha) Power (W/m 2 ) Greenhouse horticulture: more light High pressure sodium lamps are still the standard 3000 60 2000 40 1000 20 0 1996 2001 2006 2011 2016 Year 0 1996 2001 2006 2011 2016 Year Data from the Netherlands From: -Van der Knijff et al., 2006 -Van der Velden & Smit 2013-2016: Preliminary estimate Van der Velden, Wageningen Economic Research (LEI)
Many new possibilities with LED Energy efficient: HPS: 1.8 mmol/j LED: up to ±3 mmol/j Spectrum Direction (position) Timing little heat radiation; no NIR High investment cost
LEDs opens opportunities for vertical farming Full control production process Limited area Anywhere Independent of environment Sustainable, but needs lot of electricity Guarantee on quantity and quality 2-3 times higher costs
Annual energy use (MJ m -2 ) Energy usage in greenhouse tomato Present situation Target 3500 3000 2500 Heating System (20%) Heating + Humidity Next Generation Cultivation Insulation Humidity Temperature 35% reduction 2000 1500 1000 500 Combined HPS Lamps (80%) Light Additional saving if LED reduces transpiration LED reduces fungal diseases higher humidity 60% reduction by LED 0 Energy Input Energy Usage Less light energy 100-150 MJ m -2 extra heating Acknowledgement: Frank Kempkes
Annual energy use (MJ m -2 ) Annual energy use (MJ m -2 ) Energy usage in greenhouse tomato 3500 Present situation 3500 Target 3000 2500 2000 Heating System (20%) Heating + Humidity Combined 3000 2500 2000 1500 1000 HPS Lamps (80%) Light 1500 1000 Heating System 500 500 LED Lamps 0 Energy Input Energy Usage 0 Energy Input Acknowledgement: Frank Kempkes
Target of LED it be 50% programme Overall: 50% energy saving in greenhouses. Savings by smart use of LEDs: 60% less electricity for lamps (=48% energy) 30% efficiency lamp [already 40-60%) 30% efficiency light use by plant 5-6% energy saving by control of air humidity
30% higher light use efficiency (aim of LED-it-be programme with 8 PhD candidates and 3 Postdocs) 15% better light absorption (plant architecture, lamp position, spectrum) 10% higher photosynthesis 5% assimilate partitioning Humidity control: stomatal regulation, disease resistance
15% improvement light absorption Open crop architecture (long internodes & petioles) +10% crop photosynthesis Compact structure Open structure Sarlikioti, de Visser, Marcelis, 2011, Ann. Bot.
15% improvement light absorption Benefits of inter lighting: 1. Less light loss due to reflection to roof 2. Better vertical light distribution Interlighting Picture from Dueck et al.
15% improvement light absorption Inter lighting Promising, but further improvements needed: 1. Horizontal light distribution? 2. Changed leaf orientation? 3. Light on lower side of leaf? Trouwborst, van Ieperen et al
Net photosynthesis (mmol CO 2 m -2 s -1 ) Interlighting: How efficient is light on lower (abaxial) side of leaf? 14 10 6 2 Adaxial Abaxial -2 0 500 1000 1500 Incident PPFD (mmol m -2 s -1 ) Paradiso, Marcelis et al University of Naples Federico II
Effect of adding Far red to Red+Blue LEDs 0 50 112 150 End of Day mmol m -2 s -1 Far red Kalaitzoglou et al., unpublished
Effect of adding Far red to Red+Blue LEDs 0 50 112 150 End of Day mmol m -2 s -1 Far red Kalaitzoglou et al., unpublished
Better light absorption by changing morphology? Example of blue light effects on morphology Solar spectrum (plasma lamp) in climate chamber Total intensity (100 mmol m -2 s -1 ) Blue LED 0-50% and 100-50% solar spectrum High blue fraction low light interception high leaf photosynthesis rate 0% Blue 5% Blue 30% Blue 50% Blue Kalaitzoglou et al., unpublished
Photosynthesis efficiency Relative qu 10% 0.6 improvement photosynthesis Spectral effects 0.4 Spectrale effecten hangen af van bladkleur Rood 100% blad: anthocyaan absorbeert groen licht, maar draagt niet bij aan fotosynthese 80% 0.2 60% real sunlight artificial sunlight artificial shadelight Red leaf Green leaf 40% 20% 0.0 Absorbed light 0% 400 500 600 700 800 400 450 500 550 600 650 700 750 Wave length (nm) Wavelength (nm) Paradiso et al., 2011
Relative quantum yield Relative quantum 0.8 10% improvement photosynthesis Spectral effects smaller at canopy level 0.6 1.2 0.4 1.0 0.8 0.6 0.2 0.4 Crop (modelled) real sunlight artificial sunlight artificial shadelight Single leaf (observed) 0.2 0.0 0.0 Incident light 400 450 500 550 600 650 700 750 Wavelength (nm) 400 450 500 550 600 650 700 750 Wavelength (nm) Paradiso et al., 2011
Dynamic photosynthesis Response when lights are turned on. Faster at high CO 2 Kaiser et al., Ann. Bot (2016)
10% improvement photosynthesis Lighting at moments of high efficiency continuous monitoring photosynthesis
Photosynthesis (mmol / m 2 leaf / s) Photosynthesis (mmol / m 2 floor / s) Plant sensors are available now. Models used for upscaling sensor info of a leaf to whole crop (Photosynthesis leaf is not equal to crop) leaf crop 40 40 20 20 0 0 400 800 1200 0 0 400 800 1200 PAR (mmol m -2 s -1 ) PAR (mmol m -2 s -1 )
Dry mass (%) 5% improvement by better assimilate partitioning More fruits? Less leaves? 100 80 25 38 60 40 20 22 53 27 35 Fruit Stem Leaf 0 Red Blue Red Blue Farred Yongran Ji et al., unpublished
Comparing 40 tomato genotypes under different light environments
Light spectrum affects growth and morphology (pictures from 1 genotype) Control 100%R 88R/12B 100%B Control Extra FR Ouzounis et al, unpublished
Total biomass (g) Total biomass Response of some genotypes 1 2 3 Genotypes From: Ouzounis et al., Wageningen Univ.
Lesion area (mm 2 ) Ratio red to far red light may affect susceptibility for botrytis (tomato) 80 60 40 20 a b 0 WL RB WL+FR RB+FR(30)RB+FR(50) 0 Treatment 30 50 Far red light (mmol m -2 s -1 ) From: Courbier et al., Unpublished, Utrecht Univ.
L-Ascorbate (mg/100 g FW) Light on tomato fruit more vitamin C 48 36 24 12 0 Dark Light Light (300 mmol m -2 s -1 ) compared to darkness higher vitamin C in five cultivars From: Ntagkas et al, unpublished Ntagkas et al. 2016 acta Hort. 1134: 351-356
Post-harvest lighting Cut lettuce, after 5 days In darkness In light From: Ernst Woltering
Conclusions Light has many aspects Intensity Direction Spectrum Heat (energy) All plant processes in control Photosynthesis, growth, development Quality Disease Health related compounds Light should be in balance with other growth conditions
Thank you for your attention! Course on lighting: 7-9 Feb 2018 12-14 Feb 2018 Student Challenge Design the Ultimate Urban Greenhouse WWW.HPP.WUR.NL