Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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Vervolgonderzoek emissiearme Lisianthus
Raaphorst, Marcel ; Eveleens, Barbara ; Burg, Rick van der; Schuddebeurs, Lisanne - \ 2017
Bleiswijk : Wageningen UR Glastuinbouw (Rapport GTB 1440) - 30
kasgewassen - kassen - glastuinbouw - snijbloemen - emissiereductie - voedingsstoffen - gewasbescherming - kooldioxide - substraten - cultuur zonder grond - fusarium - bodemschimmels - kunstmatige verlichting - kunstlicht - greenhouse crops - greenhouses - greenhouse horticulture - cut flowers - emission reduction - nutrients - plant protection - carbon dioxide - substrates - soilless culture - soil fungi - artificial lighting - artificial light
Lisianthus growers look for methods to minimise the emission of nutrients, crop protection chemicals and CO2. In 2014 and 2015, nine crops with Lisianthus have been tested at the Delphy Improvement Centre. This report describes the four trials that have been carried out in the extended research in 2016. With this extension, a distinction was made between different substrates and intensities of assimilation lighting. In addition to knowledge about light use efficiency, water use, heat use, substrate differences and growth development, these extra crop cycles have brought to light that growing Lisianthus on substrate gives a less resilient plant against soil fungi than was experienced during the first crop cycles.
Energiebesparing met LED belichting in gerbera : resultaten van 1ste jaar LED onderzoek
García, Nieves ; Weerheim, Kees ; Helm, Frank van der; Kempkes, Frank ; Visser, Pieter de; Groot, Marco - \ 2016
Bleiswijk : Wageningen UR Glastuinbouw (Report GTB 1389) - 66
gerbera - glastuinbouw - kasgewassen - kassen - kastechniek - teelt onder bescherming - energiebesparing - led lampen - kunstlicht - kunstmatige verlichting - licht - verlichting - greenhouse horticulture - greenhouse crops - greenhouses - greenhouse technology - protected cultivation - energy saving - led lamps - artificial light - artificial lighting - light - lighting
In the winter 2013-2014 Wageningen UR Greenhouse Horticulture conducted studies on energy saving opportunities in the cultivation of gerbera, CV Kimsey. The research was funded by the program Greenhouse as Energy Source from the Ministry of Economic Affairs and LTO Glaskracht. The contribution of LED lighting, LED interlighting, a lower intensity of the light installation, and light integration was investigated. An electricity savings of 45% was the target. By using LED lighting a 20% electricity savings are possible in exchange for a small production loss (2.3%) and some additional heat demand (9%). By installing 80 instead of 100 μmol light gerbera growers can save another 20% energy costing only 3.9% production without sacrificing quality. The targeted PAR sum for light integration was too high to contribute to electricity savings. The use of 20 μmol LED interlighting in combination with 60 μmol top light (LED or SON-T) resulted in significantly less production (9%) and lower flower quality: shorter and lighter, smaller diameter and a lower % of dry matter) than 80 μmol top light.
Duurzaamheid als leidraad voor roos : vervolg onderzoek Perfecte Roos: energiezuinig geteeld
Gelder, Arie de; Warmenhoven, Mary ; Knaap, Edwin van der; Burg, Rick van der - \ 2016
Bleiswijk : Wageningen UR Glastuinbouw (Rapport GTB 1412) - 50
rozen - teelt onder bescherming - kasgewassen - glastuinbouw - duurzame landbouw - energiebesparing - elektriciteit - assimilatie - kunstlicht - kunstmatige verlichting - verlichting - koelen - meeldauw - geïntegreerde bestrijding - geïntegreerde plagenbestrijding - roses - protected cultivation - greenhouse crops - greenhouse horticulture - sustainable agriculture - energy saving - electricity - assimilation - artificial light - artificial lighting - lighting - cooling - mildews - integrated control - integrated pest management
The project Sustainable rose cultivation aimed to achieve a sustainable and energy efficient rose cultivation by a controlled use of assimilation lighting, an optimum use of the cooling and an integrated control strategy for mildew. The production came to 320 stems.m-2 average weight 54 grams. The branch length and bud size varied through the season. There was no saving on electricity. There was a significant saving on heat. The improvement of the energy efficiency was totally determined by the reduction of the heat consumption. The light utilization efficiency was 2:44 g.mol-¹ and increased compared to the previous year. Cooling and forced ventilation had a positive effect on the stem elongation in the autumn. The installation with forced ventilation from above combined with the screen had a favourable effect on the climate, especially in the humidity control under a largely (95-98%) closed screen. The payback period of the investment in airconditioning is within 3 years.
Plantmonitoring op basis van fotosynthese sensoren : ontwikkelen en testen van sensoren
Dieleman, Anja ; Bontsema, Jan ; Jalink, Henk ; Snel, Jan ; Kempkes, Frank ; Voogt, Jan ; Pot, Sander ; Elings, Anne ; Jalink, Vincent ; Meinen, Esther - \ 2016
Bleiswijk : Wageningen UR Glastuinbouw (Rapport GTB 1405) - 86
teelt onder bescherming - glastuinbouw - kastechniek - sensors - fotosynthese - kooldioxide - energie - energiebesparing - verlichting - kunstlicht - kunstmatige verlichting - ventilatie - kunstmatige ventilatie - fluorescentie - tomaten - solanum lycopersicum - protected cultivation - greenhouse horticulture - greenhouse technology - photosynthesis - carbon dioxide - energy - energy saving - lighting - artificial light - artificial lighting - ventilation - artificial ventilation - fluorescence - tomatoes
The basic process for crop growth and production is photosynthesis. Measuring crop photosynthesis is therefore important to monitor the status of the crop and whether the greenhouse climate is set to the needs of the crop. In this project, two monitoring systems for crop photosynthesis were developed and tested. (1) The crop photosynthesis monitor is a soft sensor that can calculate the CO2 uptake of an entire crop. The basis for these calculations are the balance between CO2 supply and CO2 loss via ventilation and crop photosynthesis. By measuring the CO2 concentration and humidity inside and outside the greenhouse, the crop photosynthesis can be calculated. (2) The CropObserver is a fluorescence sensor that measures the light use efficiency of photosynthesis of a large crop area (3 x 3 m2). The crop receives light pulses from a laser in the top of the greenhouse, the sensor measures the fluorescence signal of the crop. Both sensors were tested in a tomato crop in 2014 with promising results. The sensors functioned without problems and delivered patterns of daily photosynthesis which matched the reference measurements reasonably well up to well.
Microalgae production in a biofilm photobioreactor
Blanken, Ward - \ 2016
University. Promotor(en): Rene Wijffels, co-promotor(en): Marcel Janssen. - Wageningen : Wageningen University - ISBN 9789462578425 - 234
algae - algae culture - biofilms - bioreactors - growth - production costs - biomass - artificial lighting - photosynthesis - carbon dioxide - algen - algenteelt - bioreactoren - groei - productiekosten - biomassa - kunstmatige verlichting - fotosynthese - kooldioxide

Microalgae can be used to produce high-value compounds, such as pigments or high value fatty acids, or as a feedstock for lower value products such as food and feed compounds, biochemicals, and biofuels. In order to produce these bulk products competitively, it is required to lower microalgae production cost. Production costs could be reduced by employing microalgae biofilms as a production platform. The main advantages of microalgae biofilms are a direct harvest of concentrated microalgae paste, and the uncoupling of the hydraulic retention time from the microalgal retention time. The latter allows to decrease the liquid volume or to employ dilute waste streams. To successfully employ biofilms, however, it is required that microalgal biofilms can be cultivated at high productivity and high photosynthetic efficiency. The aim of this thesis was to optimize the productivity of microalgal biofilms.

Light energy drives microalgal growth. Sunlight is free and abundant, but sunlight intensity varies over the day and the seasons. This makes it impossible to maintain optimal production conditions throughout the day. These fluctuations in irradiance can be prevented by applying artificial lighting. Although, artificial lighting will supply a constant light intensity and thus increase productivity and simplify process control, it will also increase microalgae production cost. A quantitative evaluation of lighting costs and energy requirement was still missing and this was the topic of Chapter 2. The costs related to artificial lighting were identified as 25.3 $ per kilogram of dry-weight biomass, with only 4% to 6% of the electrical energy required to power the lamps eventually stored as chemical energy in microalgal biomass. Energy loss and increased production cost may be acceptable for the production of high value products, but in general they should be avoided.

In Chapter 3, a photobioreactor design based on a rotating biological contactor (RBC) was introduced and used as a production platform for microalgal biomass cultivated in a biofilm. In the photobioreactor, referred to as the Algadisk, microalgae grow in biofilm on vertical rotating disks partially submerged in water with dissolved nutrients. The objective was to evaluate the potential of the Algadisk photobioreactor, and identify the window of operation of the process with respect to the effects of disk roughness, disk rotation speed and CO2 concentration. These parameters were evaluated in relation to biomass productivity, photosynthetic efficiency, and the long-term cultivation stability of the production process.

The mesophilic green microalga Chlorella sorokiniana was used as a model organism. In the lab-scale Algadisk reactor, a productivity of 20.1 ±0.7 gram per m2 disk surface per day and a biomass yield on light of 0.9 ±0.04 gram dry weight biomass per mol photons were obtained. This productivity could be retained over 21 weeks without re-inoculation. To obtain maximal and stable productivity it was important that the disk surface provides a structure that allows biomass retention on the disk after harvest. The retained biomass acts as inoculum for the new biofilm and is therefore essential for quick biofilm regrowth. Most important process parameters were CO2­ supply, temperature, and pH. Although deviations of these parameters from the optimal conditions resulted in productivity loss, the system quickly recovered when optimal conditions were restored. These results exhibit an apparent opportunity to employ the Algadisk photobioreactor and biofilm systems in general at large scale for microalgae biomass production provided CO2 supply is adequate.

In order to better understand the process conditions inside the biofilm a model was developed in the further chapters. These mathematical models were calibrated and validated with dedicated experiments. In Chapter 4 first a general applicable kinetic model was developed able to predict light limited microalgal growth. This model combines a mathematical description for photoautotrophic sugar production with a description for aerobic chemoheterotrophic biomass growth. The model is based on five measurable biological parameters which were obtained from literature for the purpose of this study. The model was validated on experiments described in literature for both Chlorella sorokiniana and Chlamydomonas reinhardtii. The specific growth rate was initially predicted with a low accuracy, which was most likely caused by simplifications in the light model and inaccurate parameter estimations. When optimizing the light model and input parameters the model accuracy was improved and validated. With this model a reliable engineering tool became available to predict microalgal growth in photobioreactors. This microalgal growth model was included in the biofilm growth models introduced in Chapters 5 and 6.

In Chapter 5 microalgal biofilms of Chlorella sorokiniana were grown under simulated day-night cycles at high productivity and high photosynthetic efficiency. The experimental data under day/night cycles were used to validate a microalgal biofilm growth model. For this purpose the light limited microalgal growth model from Chapter 4 was extended to include diurnal carbon-partitioning and maintenance under prolonged dark conditions. This new biofilm growth model was then calibrated and validated experimentally. Based on these experiments and model simulations no differences in the light utilization efficiency between diurnal and continuous light conditions were identified. Indirectly this shows that biomass lost overnight represents sugar consumption for synthesis of new functional biomass and maintenance related respiration. This is advantageous, as this result shows that it is possible to cultivate microalgae at high photosynthetic efficiencies on sunlight and that the night does not negatively impact overall daily productivity. Long periods of darkness resulted in reduced maintenance related respiration.

Based on simulations with the validated biofilm growth model it could be determined that the photosynthetic efficiency of biofilm growth is higher than that of suspension growth. This is related to the fact that the maintenance rate in the dark zones of the biofilm is lower compared to that in the dark zones of suspension cultures, which are continuously mixed with the photic zone.

In Chapter 3 it was identified that concentrated CO2 streams are required to obtain high productivities. However, over-supplying CO2 results into loss of CO2 to the environment and is undesirable for both environmental and economic reasons. In Chapter 6 the phototrophic biofilm growth model from Chapter 5 was extended to include CO2 and O2 consumption, production, and diffusion. The extended model was validated in growth experiments with CO2 as limiting substrate. Based on the validated model the CO2 utilization and productivity in biofilm photobioreactors were optimized by changing the gas flow rate, the number of biofilm reactors in series, and the gas composition. This resulted in a maximum CO2 utilization efficiency of 96% by employing flue gas, while the productivity only dropped 2% compared to non-CO2 limited growth. In order to achieve this 25 biofilm reactors units, or more, must be operated in series. Based on these results we conclude that concentrated CO2 streams and plug flow behaviour of the gaseous phase over the biofilm surface are essential for high CO2 utilization efficiencies and high biofilm productivity.

In Chapter 7 the implications of these studies for the further development of biofilm photobioreactors was discussed in the light of current biofilm photobioreactor designs. Design elements of state of the art biofilm photobioreactors, were combined into a new conceptual biofilm photobioreactor design. This new design combines all advantages of phototrophic biofilms minimizing the amount of material required. Further improvements by means of process control strategies were suggested that aim for maximal productivity and maximal nutrient utilization efficiency. These strategies include: control of the biofilm thickness, control of the temperature, and optimized nutrient supply strategies.

Effect straatverlichting op paddentrek
Grunsven, R.H.A. van; Joosten, K. ; Creemers, R. - \ 2015
RAVON 17 (2015)3. - p. 56 - 58.
padden - migratie - habitats - habitatfragmentatie - habitatverbindingszones - verlichting - kunstmatige verlichting - wildbescherming - toads - migration - habitat fragmentation - habitat corridors - lighting - artificial lighting - wildlife conservation
Al duizenden jaren gaan padden in het vroege voorjaar ’s nachts op pad naar voortplantingswateren om daar te paren en eieren af te zetten. De wereld om hen heen is in al die jaren sterk veranderd. Wegen doorkruisen hun leefgebied en straatverlichting langs de wegen is eerder regel dan uitzondering. En dat heeft effect op de paddentrek, zo blijkt uit een lichtonderzoek.
Efficiënt omgaan met elektriciteit bij chrysant : opties voor besparing
Raaphorst, M.G.M. ; Dueck, T.A. ; Kempkes, F.L.K. ; Veld, P. de; Corsten, R. - \ 2015
Bleiswijk : Wageningen UR Glastuinbouw (Rapport GTB 1370) - 32
chrysanthemum - teelt onder bescherming - kasgewassen - sierteelt - elektriciteit - kunstlicht - kunstmatige verlichting - energiebesparing - led lampen - afdeklagen - reflectie - diffuus glas - snijbloemen - glastuinbouw - protected cultivation - greenhouse crops - ornamental horticulture - electricity - artificial light - artificial lighting - energy saving - led lamps - coatings - reflection - diffused glass - cut flowers - greenhouse horticulture
Trials have demonstrated that that the heat use for Chrysanthemum can be considerably reduced if the right measures are taken. If these reduction can also be realised with lighting, then we are well on the way to climateneutral Chrysanthemum cultivation. In order to identify energy saving measures with lighting, Wageningen UR Greenhouse Horticulture along with growers and DLV-Plant have calculated energy savings for the most promising measures. The most important measures also appear to entail a large investment, such as ARcoatings, diffused glass, LED lighting or a super-reflecting greenhouse structure. More accessible measures, such as soil reflection (for example, styromull), can also lead to a 5% lower electricity costs. In addition, there are many small measures that are expected to increase the energy efficiency. Examples are the stage-dependent lighting regime or an extended propagation. However, it is not yet known how large the effects of these measures are and if they are also economically viable
Stuurlicht in de Glastuinbouw : 1. Kansen voor energiebesparing?
Dueck, T.A. ; Hogewoning, S. ; Pot, S. ; Meinen, E. ; Trouwborst, G. ; Kempkes, F.L.K. - \ 2015
Bleiswijk : Wageningen UR Glastuinbouw (Rapport GTB 1349) - 56
teelt onder bescherming - gewasproductie - gewasopbrengst - gewaskwaliteit - gewasfysiologie - kunstlicht - kunstmatige verlichting - plantenfysiologie - aanvullend licht - blauw licht - verrood licht - rood licht - phalaenopsis - kalanchoe - chrysanten - protected cultivation - crop production - crop yield - crop quality - crop physiology - artificial light - artificial lighting - plant physiology - supplementary light - blue light - far red light - red light - chrysanthemums
This report focusses on energy efficient steering light applications by energy efficient lighting systems, but especially with new possibilities to influence crop growth and production with the light spectrum. After an introduction of the physiological background and application of steering light, new applications for steering light in the future are described with respect to energy saving opportunities. Possible scenario’s for steering light are presented for phalaenopsis, chrysanthemum and kalanchoë.
Richtinggevende beelden voor klimaat neutrale glastuinbouw
Poot, E.H. ; Garcia Victoria, N. ; Gelder, A. de; Kempkes, F.L.K. ; Marcelis, L.F.M. ; Raaphorst, M.G.M. ; Weel, P.A. van; Zwart, H.F. de - \ 2015
Bleiswijk : Wageningen UR Glastuinbouw (Rapport GTB 1365) - 50
glastuinbouw - duurzame landbouw - energiebesparing - klimaatregeling - kastechniek - belichting - kunstmatige verlichting - teeltsystemen - tomaten - rozen - snijbloemen - greenhouse horticulture - sustainable agriculture - energy saving - air conditioning - greenhouse technology - illumination - artificial lighting - cropping systems - tomatoes - roses - cut flowers
With financial support of the Dutch ministry of EZ and Dutch horticulture product board PT, Wageningen UR Greenhouse Horticulture designed and simulated concepts with savings of 70% on thermal energy in the greenhouse cultivation of tomatoes, and 50% on electricity for artificial light in the greenhouse cultivation of roses. The tomato concept is based on prototypes “VenLow Energy Greenhouse” and “Next Generation Semiclosed Greenhouse”, and is able to produce tomatoes with 12 m3*m-2*year-1 of natural gas equivalents. Options for energy savings on electricity for assimilation lighting for roses cv. ‘Red Naomi!’ were developed regarding a roadmap with five steps. With significantly less hours of artificial lighting, more solar radiation by using less screens during day time, 3-day light integration and application of diffuse glass with AR coating and LED lights, 50% saving on energy for lighting seems possible without concessions to production. However this system seems not economic feasible yet.
Meerlagenteelt van stek vooral in de winter voordelig
Dalfsen, P. van; Even, S. - \ 2013
De Boomkwekerij 26 (2013)20. - ISSN 0923-2443 - p. 14 - 15.
teeltsystemen - sierplanten - vermeerderingsmateriaal - meerlagenteelt - belichting - kunstmatige verlichting - lichtgevende dioden - innovaties - proeven - winter - led lampen - cropping systems - ornamental plants - propagation materials - multi-layer cultivation - illumination - artificial lighting - light emitting diodes - innovations - trials - led lamps
Een meerlagensysteem biedt bij de teelt van stek vooral in de winter grote voordelen. De wortelvorming komt sneller op gang waardoor meer rondes per jaar kunnen worden gemaakt. Dat blijkt uit proeven bij Boereboom stekcultures in Eindhoven. Het onderzoek zet een belangrijke stap naar het stekbedrijf van de toekomst
Kwaliteit roos bij telen volgens licht emissie regels
Garcia Victoria, N. ; Gelder, A. de; Speetjens, S.L. - \ 2012
Bleiswijk : Wageningen UR Glastuinbouw (Rapporten WUR GTB 1176) - 82
kunstmatige verlichting - emissie - glastuinbouw - milieueffect - wetgeving - landbouwkundig onderzoek - Nederland - artificial lighting - emission - greenhouse horticulture - environmental impact - legislation - agricultural research - Netherlands
In het besluit Glastuinbouw van 21 februari 2002 zijn regels vastgelegd voor lichtemissie door bedrijven met assimilatie belichting. Deze regels voor lichtemissie zijn onderwerp van gesprek. In overleg van LTO Noord Glaskracht met gemeenten en door een aangenomen motie van 30 juni 2011 in de Tweede Kamer is afgesproken om in overleg en na onderzoek te komen tot hanteerbare en werkbare regels. Op verzoek van LTO-Noord Glaskracht en de Landelijke Gewas Commissie roos is met Financiering van het Productschap Tuinbouw een onderzoek uitgevoerd bij Wageningen UR Glastuinbouw in Bleiswijk om na te gaan wat de invloed op de kwaliteit is bij telen volgens de nu geldende lichtemissie regels en bij telen volgens nieuwe regels zoals die nu onderwerp van gesprek zijn. Het onderzoek heeft bestaan uit twee onderdelen: een experiment (teeltproef) en een modelstudie.
Book of Abstracts 7th International Symposium on Light in Horticultural Systems ISHS Lightsym2012
Hemming, S. ; Heuvelink, E. - \ 2012
Leuven : ISHS - 214
kunstlicht - kunstmatige verlichting - lichtgevende dioden - aanvullend licht - glastuinbouw - led lampen - artificial light - artificial lighting - light emitting diodes - supplementary light - greenhouse horticulture - led lamps
Energieplan Greenportkas II: Verkenning van de besparingsmogelijkheden van het kasconcept
Kempkes, F.L.K. ; Verkerke, W. ; Poot, E.H. - \ 2012
Wageningen : Wageningen UR Glastuinbouw (Rapporten GTB 1141) - 32
kastechniek - energiebesparing - lichtgevende dioden - kunstmatige verlichting - gecoat glas - ontvochtiging - binnenklimaat - tomaten - teelt onder bescherming - nederland - greenhouse technology - energy saving - light emitting diodes - artificial lighting - coated glass - dehumidification - indoor climate - tomatoes - protected cultivation - netherlands
Op basis van de meest actuele stand van zaken in het onderzoek aan energiezuinige tomatenteelt in kassen en de plannen van de ondernemer, is een concept kassysteem Greenportkas II opgesteld. Het Greenportkas II concept is vergeleken met verschillende energiebesparingsprojecten bij tomaat. Onderling vergelijk van deze projecten is bijzonder lastig omdat de uitgangspunten soms zeer sterk verschillen. In dit rapport is geprobeerd de uitgangspunten en resultaten van deze projecten, waaronder ook Greenportkas I, onderling wel vergelijkbaar te maken, door alles terug te rekenen tot inzet van primaire energie.
PlantLab claimt enorme productieverhoging: Ei van Columbus of verkooppraatjes? (interview met o.a. Leo Marcelis)
Sleegers, J. ; Marcelis, L.F.M. - \ 2011
Vakblad voor de Bloemisterij 66 (2011)31. - ISSN 0042-2223 - p. 32 - 34.
sierteelt - sierplanten - kassen - glastuinbouw - kunstmatige verlichting - kunstlicht - belichting - temperatuur - bedrijfsvoering - ornamental horticulture - ornamental plants - greenhouses - greenhouse horticulture - artificial lighting - artificial light - illumination - temperature - management
Tot drie keer meer productie claimt PlantLab in Den Bosch te halen met zijn Plant Production Units. Belichten met led en de plant centraal stellen staan aan de basis van dat succes. Andere wetenschappers staan te popelen om de resultaten te onderzoeken.
Gedrag van schieraal rond een viswering met stroboscooplampen bij gemaal IJmuiden. DIDSON metingen
Keeken, O.A. van; Burggraaf, D. ; Winter, H.V. - \ 2011
IJmuiden : IMARES (Rapport / IMARES Wageningen UR C072.11) - 45
vismigratie - pompstations - european eels - palingen - anguilla - sluizen - mortaliteit - diergedrag - kunstmatige verlichting - noord-holland - fish migration - pumping stations - eels - sluices - mortality - animal behaviour - artificial lighting
Om de sterfte van uittrekkende schieraal in het gemaal van IJmuiden in het Noordzeekanaal te verminderen heeft Rijkswaterstaat Noord-Holland een meerjarig en multidisciplinair onderzoek uitgezet om effectieve maatregelen te kunnen nemen en te testen op effectiviteit.
Onderzoek bolblad chrysant: Resultaten praktijkonderzoek op bedrijven in De Lier en Hoek van Holland
Maaswinkel, R.H.M. ; Ieperen, W. van; Kersten, M. - \ 2011
Bleiswijk : Wageningen UR Glastuinbouw (Rapporten GTB 1079) - 32
chrysanthemum - bladeren - afwijkingen, planten - symptomen - daglicht - kunstmatige verlichting - verrood licht - aanvullend licht - schijnbaar positieve resultaten - glastuinbouw - nederland - leaves - plant disorders - symptoms - daylight - artificial lighting - far red light - supplementary light - false positive results - greenhouse horticulture - netherlands
During the growing season 2010-2011, on two nurseries, research was done on bulbous leaf by chrysanthemum. The amount of daylight is limited during the winter. It is common that the chrysanthemum-plants are lighted by SON-T lamps. The spectrum of these lamps (550 – 620 nanometres) is not corresponding to the daylight. Especially the far-red part of the spectrum is during the winter scarcely present. It supposed that caused by the shortage of far-red light the conversion of starch does not expired optimum at night for varieties which are sensitive for bulbous leaf. The natural shortage of far-red light in the spectrum can be supplemented by lightning with bulbs. On both nurseries standard cultivation is compared with cultivation in which, after a dark period of one hour light is given with bulbs during one hour. On both nurseries there were limited problems with bulbous leaf. Only one time (with the variety Anastasia Pink Star) it was possible to prevent bulbous leaf with given light by bulbs. Further on it appears that delaying of the bud formation was occurred by lighting with bulbs during the dark period.
On the photosynthetic responses of crops to intracanopy lighting with light emitting diodes
Trouwborst, G. - \ 2011
University. Promotor(en): Olaf van Kooten, co-promotor(en): Wim van Ieperen; Jeremy Harbinson. - [S.l.] : S.n. - ISBN 9789085858621 - 154
kasgewassen - fotosynthese - fotosynthese van het kroondak - kunstmatige verlichting - lichtgevende dioden - lichtpenetratie - glastuinbouw - lichtverdeling - greenhouse crops - photosynthesis - canopy photosynthesis - artificial lighting - light emitting diodes - light penetration - greenhouse horticulture - light distribution

Key words: Cucumis sativus, intracanopy lighting, light-emitting diodes (LEDs), light distribution, light interception, light quality, photosynthesis, photosynthetic acclimation

Assimilation lighting is a production factor of increasing importance in Dutch greenhouse horticulture. Assimilation lighting increases production levels, improves product quality and opens possibilities for year round production. As a drawback, this use of assimilation lighting increases energy inputs and CO2-emission.
Intracanopy lighting (with LEDs) is a technique to enhance the light use efficiency by changing the position of (a part of ) the lamps from above to within the canopy of greenhouse grown crops. Intracanopy lighting (IL) firstly reduces reflection and transmission losses of the supplemental lighting on crop level. These losses are high in traditional top-lighting systems, hence IL yields a higher light absorption on crop level. Secondly, IL creates a more homogenous vertical light distribution which can result in higher light use efficiencies. The aim of present study was to obtain insights in photosynthetic acclimation in response to irradiance level and spectrum in the framework of the applicability of LEDs as light source for intracanopy lighting in indeterminate growing vegetable crops. Intracanopy lighting may vary in (1) position within the crop, in (2) irradiance level and in (3) spectrum.
Leaves deeper in the canopy are older. If leaf age negatively affects the photosynthetic capacity (Amax), then potential positions of IL-lamps reduce. By growing tomato plants horizontally so that irradiance was similar for all leaves from 0-70 days old, it is concluded that during the normal life-span of tomato leaves in cultivation, irradiance and not ageing is the most important factor affecting Amax.
In winter, natural irradiances are low so that new developing leaves acclimate to low irradiances. Later on in their life time these leaves could be exposed to higher irradiances owing to IL. The question arose if cucumber leaves which develop under low irradiance can acclimate to a moderate irradiance. Acclimation of photosynthesis occurred within 7 days but photosynthesis at moderate irradiance and Amax did not reach to that of leaves developed under moderate irradiance. This reveals the importance of photosynthetic acclimation during the leaf developmental phase for crop productivity in scenarios with realistic, moderate fluctuations in irradiance that leaves can be exposed to.
By growing plants under seven different combinations of red and blue light, blue light is shown to have both a qualitative and a quantitative effect on leaf development. Only leaves developed under red light (0% blue) displayed a dysfunctional photosynthetic operation (“red light syndrome”), which was largely alleviated by only 7% blue. Quantitatively, leaf responses to an increasing blue light percentage resembled responses associated with an increase in irradiance.
Leaves developed under red light exposed to a mixture of red and blue (RB) completely recovered within 4 days after exposure to RB-light but remained limited in other leaf parameters, showing limitations in plasticity due to constraints arising from the prior leaf development. Leaves developed under RB also revealed the “red light syndrome” within 7 days of red illumination.
Lastly, the effects of intracanopy lighting with LEDs on the production and development of a cucumber crop was investigated in winter. In the IL-treatment, LEDs supplied 38% of the supplemental irradiance within the canopy; the remaining 62% was supplied as top lighting by High-Pressure Sodium (HPS) lamps. The control was 100% top lighting (HPS lamps). Intracanopy lighting resulted in a greater Amax for leaves at deeper canopy layers but did not increase total biomass or fruit production. This was partly due to a reduced light interception caused by extreme leaf curling, which counteracted the expected higher light absorption by the crop, and partly to a lower dry matter partitioning to the fruits, and thus a greater dry matter partitioning to the leaves compared to the control. The effect of these factors on fruit yield was quantified using a explanatory crop model. Model calculations revealed a large negative effect on the fruit yield due to the greater partitioning to the leaves, whereas the negative effect of leaf curling was small. The effect of a greater Amax at deeper canopy layers was slightly positive. The last however might have indirectly caused the greater partitioning to the leaves as the greater Amax was associated with a preserved leaf mass per area.

Maatregelen ter vermindering van fijnstofemissie uit de pluimveehouderij : verkenning effecten alternatieve lichtschema's op fijnstofemissie bij leghennen = Measures to reduce fine dust from poultry houses : investigation of the effects of light regimes on fine dust in layer houses
Emous, R.A. van; Ogink, N. - \ 2010
Lelystad : Wageningen UR Livestock Research (Rapport / Wageningen UR Livestock Research 347) - 11
dierenwelzijn - luchtkwaliteit - pluimveehouderij - hennen - fijn stof - emissie - licht - kunstmatige verlichting - animal welfare - air quality - poultry farming - hens - particulate matter - emission - light - artificial lighting
Light intensity has a large effect on the activity of laying hens. A lower intensity gives less activity and thus less emission of fine dust. The effect on the welfare of hens is difficult to estimate.
LED ligt gevoelig (Confrontatie Nico van der Houwen en Tom Dueck)
Petit, R. ; Dueck, T.A. - \ 2010
Groenten en Fruit Magazine 2010 (2010)7/8. - ISSN 1879-7318 - p. 34 - 35.
tuinbouw - kunstmatige verlichting - kunstlicht - energie - duurzaamheid (durability) - glastuinbouw - energiebesparing - horticulture - artificial lighting - artificial light - energy - durability - greenhouse horticulture - energy saving
De led-lamp beroerde een gevoelige snaar bij glastuinders in Nederland. Een duurzame lamp, energiezuinig, minder lichtuitstoot. Maar ook al wil iedereen dat het een succes wordt, daarmee ben je er nog niet. Tegenvallers hebben de tuinbouw nu led-moe gemaakt.
Efficiëntie van Led-belichting bij roos
Sterk, F. ; Marcelis, L.F.M. ; Swinkels, G.L.A.M. ; Warmenhoven, M.G. ; Steenhuizen, J.W. ; Zuurbier, R. ; Dueck, T.A. - \ 2009
Bleiswijk : Wageningen UR Glastuinbouw (Rapport / Wageningen UR Glastuinbouw 304)
rosa - verlichting - kunstmatige verlichting - tuinbouw - lichtsterkte - fotosynthese - glastuinbouw - kastechniek - lighting - artificial lighting - horticulture - light intensity - photosynthesis - greenhouse horticulture - greenhouse technology
Teelt onder LED en SON-T boven- en tussenbelichting zijn met elkaar vergeleken. Lichtintensiteit van de LED bovenbelichting leverde tussen januari en maart een hogere productie per mol PAR op, zowel in aantal takken, als in het totaal gewicht van de takken. Het verschil werd kleiner naarmate het natuurlijk licht toenam. Het indivuduele takgewicht (gewicht per tak) was verhoogd onder SON-T-boven met LED-tussenbelichting. Loosvorming kwam minder voor onder LED-belichting.
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