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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    Bringing eggs and bones to light : affecting leg bone development in broiler chickens through perinatal lighting schedules
    Pol, Carla W. van der - \ 2017
    Wageningen University. Promotor(en): B. Kemp, co-promotor(en): H. van den Brand; I.A.M. Roovert-Reijrink. - Wageningen : Wageningen University - ISBN 9789463431422 - 214
    broilers - limb bones - biological development - embryonic development - eggs - light regime - incubation - hatching - circadian rhythm - animal pathology - animal health - poultry farming - vleeskuikens - beenderen van ledematen - biologische ontwikkeling - embryonale ontwikkeling - eieren - lichtregiem - broeden - uitbroeden - circadiaan ritme - dierpathologie - diergezondheid - pluimveehouderij

    Leg bone pathologies are a common problem in broiler chickens, and they can lead to decreased welfare and poor production performance. It can be speculated that the ae­tiology of some leg bone pathologies lies, to some extent, in suboptimal early life bone development. One factor that can be speculated to affect bone development, and conse­quently leg health, in broiler chickens is application of light. Light has several properties, such as light intensity, color, duration, and schedule. The present thesis focuses on ligh­ting schedules. Aim was to investigate how lighting schedules applied during incubation and in the early post hatch period (the brooding period) affected leg bone development throughout a broiler’s life and leg health at slaughter age.

    In 4 studies, effects of eggshell temperature (EST) and lighting schedule during incuba­tion and in the brooding period on leg bone development, leg health, and production parameters were explored. The first study found that an EST of 39.4°C led to lower bone dimensions at hatch than an EST between 37.8 and 38.6°C. It was then decided that incubation experiments on bone development would best be performed at a constant EST of 37.8°C, as this is also an EST that leads to good hatchability and chick quality. In two studies, the effects of circadian lighting schedules during incubation on leg bone development and leg health were investigated. Staining of the embryonic leg bones sho­wed that applying a circadian lighting schedule of 12 hours of light, followed by 12 hours of darkness (12L:12D) resulted in an earlier onset of embryonic ossification of the tibia than continuous light (24L). Compared to 24L, 12L:12D furthermore resulted in higher tibia weight and length, and higher tibial cortical area, cortical thickness, and second moment of area around the minor axis at hatch as revealed by MicroCT scanning. It was furthermore found that 12L:12D resulted in a lower incidence of the leg pathology tibial dyschondroplasia. Continuous darkness (24D) was mostly intermediate. On the other hand, a circadian lighting schedule of 16 hours of light, followed by 8 hours of darkness (16L:8D) did not show the same stimulatory effect on leg bone development, as no dif­ferences in gene expression markers involved in embryonic ossification were found, leg bone dimensions at hatch were not increased, and bone mineral content as determined by DXA scanning was not higher for 16L:8D. It can therefore be speculated that the dark period should exceed 8 hours per day during incubation for increased bone dimensions and ossification. However, incidence and severity of the leg bone pathologies in the form of bacterial chondronecrosis with osteomyelitis and epiphyseal plate abnormalities were lowest for broilers exposed to 16L:8D during incubation, and tibial dyschondroplasia tended to be lower for 16L:8D than for 24D. Interactions between incubation and mat­ching or mismatching post hatch lighting schedules were not found. It was speculated that the endocrine factors (pineal) melatonin, growth hormone, corticosterone, and IGF- 1 were a pathway through which light affected leg bone development, but no evidence was found to support this hypothesis. Production performance was not greatly influen­ced by incubation lighting schedule, but 24L was found to result in higher body weights at slaughter age than 16L:8D and 24D. In the final experiment, lighting schedules were applied during the brooding period from day 0 to 4 after hatching and leg bone develop­ment was measured at day 4 post hatch. 24L led to increased leg bone dimensions, but lower developmental stability of the leg bones than a lighting schedule with 1 or 6 hours of darkness after every 2 hours of light.

    The overall findings of this thesis suggest that continuous light during incubation and in the brooding period had a detrimental effect on embryonic and early post hatch leg bone development and health. The involvement of endocrine factors was not clarified from the current results. Applying a light-dark rhythm during incubation may improve embryonic leg bone development and leg health at slaughter age compared to continuous light and continuous darkness, without affecting post hatch production performance, but it appears that the dark period should last longer than 8 hours per day for optimal leg bone development.

    Recente trends in de vogelstand nabij de Eerste Bathpolder en mogelijke effecten van verlengde assimilatiebelichting
    Tamis, J.E. ; Jongbloed, R.H. ; Ysebaert, T. - \ 2016
    Den Helder : Wageningen Marine Research (Wageningen Marine Research rapport C128/16) - 59
    vogels - lichtregiem - licht - glastuinbouw - natura 2000 - zeeland - birds - light regime - light - greenhouse horticulture - natura 2000 - zeeland
    In de Eerste Bathpolder in de provincie Zeeland (gemeente Reimerswaal, nabij Rilland en grenzend aan het Natura 2000-gebied Oosterschelde) is sinds 2000 een aantal kassen gevestigd in een glastuinbouwgebied. Voor elk Natura 2000-gebied gelden instandhoudingsdoelen, die aangeven welke leefgebieden en welke soorten (plant en dier) behouden of hersteld moeten worden. Eén van de mogelijke effecten van de glastuinbouwbedrijven op de nabije omgeving is effecten van zogenaamd groeilicht (assimilatiebelichting) op de buitendijkse natuur van de Oosterschelde (met name op vogels). In 2009 heeft IMARES een deskstudie, veldonderzoek en analyse van vogeltellingen uitgevoerd, op basis waarvan geen duidelijke effecten van assimilatiebelichting op de beschermde vogelsoorten zijn aangetoond (Ysebaert et al., 2009). Onlangs hebben de glastuinbouwbedrijven nieuwe belichtingsstrategieën ontwikkeld wat een reductie van de lichtuitstoot bewerkstelligt van maximaal 34% t.o.v. de bestaande situatie, gebaseerd op de totale lichtbelasting gedurende een jaar. Het voorgestelde lichtregime veroorzaakt echter in de avond (van zonsondergang tot 20.00 uur) wel een tijdelijke verhoging van de lichtbelasting, vooral in de wintermaanden. Daarom is aan Wageningen Marine Research (voorheen IMARES) gevraagd opnieuw onderzoek te doen naar de recente trends in de vogelstand en de mogelijke effecten van langer belichten op de kwalificerende (Natura 2000-) natuurwaarden nabij de Eerste Bathpolder. Dit rapport beschrijft de resultaten van dit onderzoek.
    Licht op licht: licht en verlichting in de pluimveehouderij in relatie tot beschadigend pikgedrag
    Niekerk, T.G.C.M. van; Ellen, H.H. ; Winkel, A. - \ 2015
    Livestock Research Wageningen UR (Livestock Research rapport 922) - 33
    pluimvee - licht - lichtregiem - gezichtsvermogen - verenpikken - pluimveehouderij - dierenwelzijn - dierlijke productie - hennen - huisvesting, dieren - diergezondheid - diergedrag - poultry - light - light regime - vision - feather pecking - poultry farming - animal welfare - animal production - hens - animal housing - animal health - animal behaviour
    In this report an overview is given of the technical knowledge with regards to light. light sources and the vision of poultry. Recent developments in lighting of poultry houses are mainly focused on new light sources, specifically LED, and the presence of daylight. Daylight comprises UV, which for poultry is a visual part of the spectrum. Chickens also see better in the red and green-blue spectrum. Technically it is possible to make lamps in the desired spectrum, but there is insufficient knowledge of the demands of the bird to be able to tune the lamps to their needs.
    LED light improves strawberry flavour, quality and production
    Hanenberg, M.A.A. ; Janse, J. ; Labrie, C.W. ; Verkerke, W. - \ 2015
    glastuinbouw - aardbeien - fruitteelt - belichting - led lampen - proeven op proefstations - lichtregiem - kwaliteit na de oogst - smaakonderzoek - greenhouse horticulture - strawberries - fruit growing - illumination - led lamps - station tests - light regime - postharvest quality - taste research
    Various quality parameters of strawberries can be improved by the application of extra LED lighting on the plants and fruits during cultivation. This is the finding of the demonstration of IDC Flavour in Bleiswijk in the autumn of 2014. The demonstration was performed with two common cultivars, Elsanta and Sonata. Three different illumination treatments were applied during cultivation.
    Circadian rhythms in microalgae production
    Winter, L. de - \ 2015
    Wageningen University. Promotor(en): Rene Wijffels, co-promotor(en): Maria Barbosa; Dirk Martens. - Wageningen : Wageningen University - ISBN 9789462573420 - 166
    algen - circadiaan ritme - celdeling - lichtregiem - milieufactoren - biomassa productie - procesoptimalisatie - algae - circadian rhythm - cell division - light regime - environmental factors - biomass production - process optimization

    Abstract Thesis: Circadian rhythms in microalgae production

    Lenneke de Winter

    The sun imposes a daily cycle of light and dark on nearly all organisms. The circadian clock evolved to help organisms program their activities at an appropriate time during this daily cycle. For example, UV sensitive processes, like DNA replication, can be scheduled to occur during the night (Nikaido and Johnson, 2000). In this way, the circadian clock causes rhythms in metabolic, physiological and/or behavioural events (Mittag et al., 2005). These circadian rhythms continue for some period of time following exposure to continuous light (Harding Jr et al., 1981) and have a duration of approximately 24 hours. In microalgae, circadian rhythms were observed in many processes, like nitrogen fixation, chemotaxis, photosynthesis and the cell division cycle (Mittag, 2001), which might affect the production of microalgae. Microalgae biomass can be used as source for potential biofuels, chemicals, materials, foods, feeds and high-value bioactives (Chisti, 2007; Hu et al., 2008; Wijffels and Barbosa, 2010). However, the current production process of microalgae needs to be optimized in order to become economically feasible (Norsker et al., 2011). Researchers focussed on optimizing PBR design (Molina et al., 2001; Morweiser et al., 2010; Sierra et al., 2008), operating strategies (Cuaresma et al., 2011; Morweiser et al., 2010; Olivieri et al., 2014) and microalgae metabolism (Guschina and Harwood, 2006; Klok et al., 2013a), but as of yet did not consider the possible influence of circadian rhythms on microalgae production.

    Biomass growth rate, biomass yield on light, and the biochemical composition of algal biomass are important factors in the production of microalgae. These factors are likely to be influenced by the day/night cycle and the circadian clock. Therefore, the aim of the work presented in this thesis was to obtain more insight in circadian rhythms in microalgae grown in photobioreactors.

    In chapter 2 it is described how the green microalgae Neochloris oleoabundans was grown in a photobioreactor operated as a turbidostat under continuous red LED light. Cell division in N. oleoabundans was shown to be under control of the circadian clock, and took place by multiple fission during the natural night. Due to the synchronized cell division, oscillations in biomass yield and composition were observed, despite the continuous red LED light. Synchronization disappeared under continuous white LED light, and therefore it was concluded that a blue light receptor might be involved in triggering synchronous cell division of N. oleoabundans.

    As biomass composition is also dependent on other culture conditions, the same set-up was used in chapter 3, only this time the culture was grown nitrogen-limited, as this is the most commonly used method for the production of storage components. In this way, it was shown that under nitrogen limitation the circadian clock was still timing cell division to the natural night. However, because of the lower growth rate, two subpopulations were observed which divided alternately every other day. Again, oscillations in biomass composition were observed. Neutral lipids were built up during the day, especially in cells that were arrested in their cell cycle.

    After having studied the circadian clock under continuous light conditions, a step was made to day/night cycles. Chapter 4 describes a comparison of biomass yield and composition between a synchronized culture under day/night cycles and a randomly dividing culture under continuous white LED light. In this way it was shown that circadian rhythms had a small influence on biomass yield, with biomass yield on light being 10-15% higher in synchronized cultures. Also biomass composition was influenced, as in continuous light starch never had to be spend for respiration during a dark period and therefore starch content remained higher. For the experiments with a day/night cycle, no difference was found between light supplied at constant intensity (block) or light supplied in a more natural way (sine). Therefore, providing light in a block showed to be a good and easy to operate alternative to using sinuses when working with day/night cycles in the laboratory.

    Chapter 5 takes a closer look at the multiple fission cell cycle of N. oleaobundans. Day/night cycles of different lengths and intensities were studied, as algae are exposed to different day lengths over the course of a year. Maximum growth rate and start of starch synthesis seemed to be regulated by the circadian clock and were scheduled after approximately 6-7 hours from sunrise. Therefore, they were not influenced by day length. However, day length did have an influence on biomass composition. In longer days, more starch was accumulated. The changes in biomass composition could also be correlated to the cell cycle of N. oleoabundans, and therefore knowledge about the timing of cell division showed to be important for the production of biomass with a desired concentration of protein, lipids, carbohydrates or pigments.

    In chapter 6 the implications of the overall results of this thesis for current research protocols and microalgae processes are discussed. First the occurrence of circadian rhythms in different species of microalgae is discussed, in order to establish the general nature of these rhythms. Based on the findings for N. oleoabundans, it is concluded that more research should be done using day/night cycles, as experiments under constant light are not representative for outdoor microalgae production. Still more knowledge is required on circadian rhythms in microalgae production and therefore some opportunities for future research are presented. Finally, it is discussed how manipulation of circadian rhythms might help to improve future microalgae production.

    Sturen op balans source en sink ingewikkelde zaak : temperatuur aanpassen aan de beschikbare straling
    Elings, A. ; Heuvelink, E. ; Kierkels, T. - \ 2015
    Onder Glas 2015 (2015)4. - p. 36 - 37.
    glastuinbouw - cultuurmethoden - teelt onder bescherming - lichtregiem - assimilatie - temperatuur - groenten - snijbloemen - plantenontwikkeling - energiebesparing - greenhouse horticulture - cultural methods - protected cultivation - light regime - assimilation - temperature - vegetables - cut flowers - plant development - energy saving
    ‘Met het licht meetelen’ is een bekend principe binnen Het Nieuwe Telen. Het betekent dat je de temperatuur aanpast aan het beschikbare licht. De insteek daarbij is vaak energiebesparing, maar ook vanuit plantkundig oogpunt is dat verstandig. Zo breng je source en sink meer in balans.
    Minder verbruik elektriciteit, meer licht voor de plant
    Hemming, S. - \ 2015
    Kas techniek 2015 (2015)januari. - p. 12 - 13.
    glastuinbouw - kastechniek - energie - energiebesparing - elektriciteit - lichtregiem - led lampen - kassen - snijbloemen - temperatuur - greenhouse horticulture - greenhouse technology - energy - energy saving - electricity - light regime - led lamps - greenhouses - cut flowers - temperature
    Terwijl de laatste jaren het energieverbruik voor warmte in de glastuinbouw flink is gedaald, stijgt het elektriciteitsverbruik. Volgens de LEI energiemonitor was deze in 2005 4.6 miljard kWh en in 2013 7.6 miljard kWh. Aanleiding om in het onderzoeksprogramma Kas als Energiebron een halvering van het elektriciteitsverbruik voor groeilicht bij gelijkblijvende opbrengsten als één van de belangrijke doelstellingen te formuleren.
    In search of compact pot plants without chemicals : control possible by manipulating DIF and DROP
    Heuvelink, E. ; Kierkels, T. - \ 2015
    In Greenhouses : the international magazine for greenhouse growers 4 (2015)1. - ISSN 2215-0633 - p. 40 - 41.
    glastuinbouw - potplanten - teelt - cultuurmethoden - cultivars - plantenontwikkeling - groeivertraging - groeiremmers - plantengroeiregulatoren - temperatuur - lichtregiem - greenhouse horticulture - pot plants - cultivation - cultural methods - cultivars - plant development - growth retardation - growth inhibitors - plant growth regulators - temperature - light regime
    Alternatives to growth inhibitors for pot plants are welcome. Scientific research points to cultivation practises that can inhibit growth. These offer possibilities where breeding fails to provide a solution.
    Branching determined by light level, light colour and CO2
    Heuvelink, E. - \ 2014
    In Greenhouses : the international magazine for greenhouse growers 3 (2014)3. - ISSN 2215-0633 - p. 46 - 47.
    glastuinbouw - kassen - lichtregiem - kooldioxide - vertakking - groenten - potplanten - cultuurmethoden - greenhouse horticulture - greenhouses - light regime - carbon dioxide - branching - vegetables - pot plants - cultural methods
    Growers of bushy pot plants want their plants to branch well. For tomato growers, however, this brings the arduous task of pinching out. Branching is partly determined by nature but is can be steered by the growing conditions.
    Continuous light on tomato : from gene to yield
    Velez Ramirez, A.I. - \ 2014
    Wageningen University. Promotor(en): Harro Bouwmeester, co-promotor(en): Wim van Ieperen; Dick Vreugdenhil. - Wageningen : Wageningen University - ISBN 9789462570788 - 214
    solanum lycopersicum - tomaten - licht - gewasproductie - gewasopbrengst - genen - tolerantie - lichtregiem - beschadigingen - plantenfysiologie - solanum lycopersicum - tomatoes - light - crop production - crop yield - genes - tolerance - light regime - injuries - plant physiology

    Light essentially sustains all life on planet earth surface. Plants transform light energy into chemical energy through photosynthesis. Hence, it can be anticipated that extending the daily photoperiod, using artificial light, results in increased plant productivity. Although this premise is true for many plant species, a limit exists. For instance, the seminal work of Arthur et al. (1930) showed that tomato plants develop leaf injuries if exposed to continuous light (CL). Many studies have investigated the physiological mechanism inducing such CL-induced injury. Although important and valuable discoveries were done over the decades, by the time the present project started, a detailed and proven physiological explanation of this disorder was still missing. Here, I present the results of a 5-year effort to better understand the physiological basis of the CL-induced injury in tomato and develop the tools (genetic and conceptual) to cultivate tomatoes under CL.

    After an exhaustive literature search, it was found that Daskaloff and Ognjanova (1965) reported that wild tomato species are tolerant to CL. Unfortunately, this important finding was ignored by numerous studies done after its publication. Here, we used the CL-tolerance found in wild tomatoes as a fundamental resource. Hence, the specific objectives of this thesis were to (i) better understand the physiological basis of the CL-induced injuries in tomato, (ii) identify the gene(s) responsible for CL-tolerance in wild tomato species, (iii) breed a CL-tolerant tomato line and (iv) use it to cultivate a greenhouse tomato crop under CL.

    Chapter 1 describes how innovation efforts encountered the unsolved scientific enigma of the injuries that tomato plants develop when exposed to CL. The term CL-induced injury is defined, and a detailed description of the symptoms observed in this disorder is shown. Additionally, an overview of the most important studies, influencing the hypotheses postulated and/or tested in this dissertation, is presented. Finally, a description and motivation of the main questions that this dissertation pursued to answer is presented alongside a short description of the strategy chosen to answer them.

    Chapter 2 reviews the literature, published over the last 80 years, on CL-induced injury using modern knowledge of plant physiology. By doing so, new hypotheses aiming to explain this disorder are postulated in addition to the ones collected from literature. Additionally, we highlight that CL is an essential tool for understanding the plant circadian clock, but using CL in research has its challenges. For instance, most of the circadian-clock-oriented experiments are performed under CL; consequently, interactions between the circadian clock and the light signalling pathway are overlooked. This chapter is published here.

    Chapter 3 explores the benefits and challenges of cultivating CL-tolerant tomato under CL. Considering that current commercial tomato varieties need six hours of darkness per day for optimal growth, photosynthesis does not take place during a quarter of the day. Hence, if tomatoes could be grown under CL, a substantial increase in production is anticipated. A simulation study is presented, which shows that if an ideal continuous-light-tolerant tomato genotype is used and no crop adaptations to CL are assumed, greenhouse tomato production could be 26% higher when supplementing light to 24 h day-1 in comparison with a photoperiod (including supplementary lighting) of only 18 h day-1. In addition, the expected changes in greenhouse energy budgets and alterations in crop physiological responses that might arise from cultivating tomatoes under continuous light are discussed. This chapter is published here.

    Chapter 4 maps the locus conferring CL-tolerance in wild tomatoes to chromosome seven, and shows that its introgression into modern tomato cultivars enhances yield by 20%, when grown under CL. In addition, genetic evidence, RNAseq data, silencing experiments and sequence analysis all point to the type III Light-Harvesting Chlorophyll a/b Binding protein 13 (CAB-13) gene as a major factor responsible for the tolerance. In Arabidopsis thaliana this protein is thought to have a regulatory role in balancing light harvesting by photosystems I and II. The likely mechanisms that link CAB-13 with CL-tolerance are discussed. This chapter is published here.

    Chapter 5 investigates from which part of the plant CL-tolerance originates and whether this trait acts systemically. By exposing grafted plants bearing both tolerant and sensitive shoots to CL, the trait was functionally located to the shoot rather than the roots. Additionally, an increase in continuous-light tolerance was observed in sensitive plants when a continuous-light-tolerant shoot was grafted on it. Our results show that in order to increase yield in greenhouse tomato production by using CL, the trait should be bred into scion rather than rootstock lines.

    Chapter 6 discusses the factors that differ between injurious and non-injurious light regimes. Each of these factors may potentially be responsible for triggering the injury in CL-grown tomato and was experimentally tested here. In short, these factors include (i) differences in the light spectral distribution between sunlight and artificial light, (ii) continuous signalling to the photoreceptors, (iii) constant supply of light for photosynthesis, (iv) constant photo-oxidative pressure, and (v) circadian asynchrony — a mismatch between the internal circadian clock frequency and the external light/dark cycles. The evidence presented here suggests that the continuous-light-induced injury does not result from the unnatural spectral distribution of artificial light or the continuity of the light per se. Instead, circadian asynchrony seems to be the factor inducing the injury. As the discovered diurnal fluctuations in photoinhibition sensitivity of tomato seedlings are not under circadian control, it seems that circadian asynchrony does not directly induce injury via photoinhibition as it has been proposed.

    Chapter 7 investigates a possible role for phytochromes (PHY) in CL-induced injury in tomato. Mutant and transgenic tomato plants lacking or over-expressing phytochromes were exposed to CL, with and without far-red light enrichment, to test the role of individual phytochromes on the induction and/or prevention of injury. PHYA over-expression confers complete tolerance to CL regardless the light spectrum. Under CL with low far-red content, PHYB1 and PHYB2 diminished and enhanced the injury, respectively, yet the effects were small. These results confirm that phytochrome signaling networks are involved in the injury induction under CL. The link between CAB-13 and PHYA is discussed.

    Chapter 8 investigates the role of carbohydrate accumulation in the induction of CL-induced injury in tomato by using untargeted metabolomics and transcriptomics data. These data reveal a clear effect of CL on sugar metabolism and photosynthesis. A strong negative correlation between sucrose and starch with the maximum quantum efficiency of photosystem II (Fv /Fm) was found across several abnormal light/dark cycles, supporting the hypothesis that carbohydrates play an important role in CL-induced injury. I suggest that CL-induced injury in tomato is caused by a photosynthetic down-regulation showing characteristics of both cytokinin-regulated senescence and light-modulated retrograde signaling. Molecular mechanisms linking carbohydrate accumulation with photosynthetic down-regulation are discussed.

    Chapter 9 provides a synthesis of the most important findings and proposes a generic model of CL-induced injury in tomato. I propose that CL-induced injury in tomato arises from retrograde signals that counteract signals derived from the cellular developmental program that promote chloroplast development, such that chloroplast development cannot be completed, resulting in the chlorotic phenotype. Finally, perspectives on what future directions to take to further elucidate the physiological basis of this trait and successfully implement it in greenhouses are presented.

    Meer licht toelaten in potplanten : wie durft? Proefresultaten uitdaging aan de praktijk
    Kierkels, T. ; Noort, F.R. van; Marcelis, L.F.M. - \ 2014
    Onder Glas 11 (2014)8. - p. 46 - 47.
    glastuinbouw - potplanten - belichting - lichtregiem - schaduwplanten - gewasmonitoring - instrumenten (meters) - cultuurmethoden - greenhouse horticulture - pot plants - illumination - light regime - shade plants - crop monitoring - instruments - cultural methods
    Bij de teelt van schaduwminnende potplanten gaat veel licht, en dus productie, verloren. Het project Grip op Licht heeft de grenzen opgerekt. De planten blijken, onder voorwaarden, veel meer licht aan te kunnen. Daarbij hoort wel een betere manier van monitoren.
    Guidance proposal for using available DegT50 values for estimation of degradation rates of plant protection products in Dutch surface water and sediment
    Boesten, J.J.T.I. ; Adriaanse, P.I. ; Horst, M.M.S. ter; Tiktak, A. ; Linden, A.M.A. van der - \ 2014
    Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-werkdocument 284) - 42
    oppervlaktewaterkwaliteit - pesticiden - degradatie - chemische afbraak - verontreinigde sedimenten - lichtregiem - hydrolyse - fotolyse - algen - waterplanten - waterverontreiniging - surface water quality - pesticides - degradation - chemical degradation - contaminated sediments - light regime - hydrolysis - photolysis - algae - aquatic plants - water pollution
    The degradation rate of plant protection products and their transformation products in surface water and sediment may influence their concentrations in Dutch surface water. Therefore the estimation of these rates may be an important part of the assessment of the exposure of aquatic organisms. We propose a stepped sequence of studies for estimating the rate in water going from simple and conservative to more sophisticated and more realistic studies. The sequence includes: - studies on hydrolysis and photolysis; - studies with fresh surface water in the dark; - water-sediment studies in the dark or in light; - studies with algae and macrophytes; - outdoor studies in realistic surface water systems. The usefulness of these studies for the exposure assessment in Dutch surface water is discussed.
    2SaveEnergy® kasconcept: van design naar realisatie
    Kempkes, F.L.K. ; Deursen, A. van - \ 2014
    glastuinbouw - kassen - constructie - innovaties - energiebesparing - lichtregiem - lichtdoorlating - economische analyse - greenhouse horticulture - greenhouses - construction - innovations - energy saving - light regime - light transmission - economic analysis
    De doelstelling van dit onderzoek is de ontwikkeling en realisatie van een kasconcept dat een potentieel hoge energie besparing kan bereiken zonder dat dit ten koste gaat van de productie en of productkwaliteit bij een beperkt investeringsniveau.
    Grip op Licht: Plantmonitoring bij phalaenopsis
    Snel, J.F.H. ; Noort, F.R. van; Marcelis, L.F.M. - \ 2014
    phalaenopsis - cultuurmethoden - lichtregiem - belichting - temperatuur - gewasmonitoring - glastuinbouw - energiebesparing - phalaenopsis - cultural methods - light regime - illumination - temperature - crop monitoring - greenhouse horticulture - energy saving
    Het Nieuwe Telen bespaart energie door meer licht toe te laten, de temperatuur overdag hoger op te laten lopen en ’s nachts verder te laten zakken. Bij potplanten zorgt het risico op lichtschade ervoor dat de tuinder de grenzen niet kan/durft op te zoeken en minder energie bespaart. De doelstelling van dit onderzoek is het realiseren van 50% energiebesparing (16 i.p.v. 32 m3/m2 gas) bij gelijke kwaliteit en teeltduur door: energie besparen door HNT en minder belichten, en het verhogen van de productie door meer diffuus licht toe te laten.
    Efficiënt gebruik van elektriciteit in belichte tomaat
    Dieleman, J.A. ; Janse, J. - \ 2014
    glastuinbouw - solanum lycopersicum - tomaten - belichting - led lampen - lichtregiem - cultuurmethoden - energiebesparing - efficiëntie - greenhouse horticulture - solanum lycopersicum - tomatoes - illumination - led lamps - light regime - cultural methods - energy saving - efficiency
    In de afgelopen jaren zijn door Wageningen UR Glastuinbouw proeven gedaan waarin een vergelijking werd gemaakt tussen LEDs en SON-T belichting, met en zonder tussenbelichting met LEDs. Uit deze proeven bleek dat het prima mogelijk is met alleen LED licht te telen, als extra warmte wordt ingebracht om de planttemperatuur op peil te houden. De doelstelling van dit onderzoek is het verlagen van het elektriciteitsgebruik in de belichte tomatenteelt en kennis en begrip van plantprocessen op het gebied van efficiënt gebruik van licht door de plant.
    Grip op licht – Energiebesparing en diffuus licht bij potplanten
    Noort, F.R. van; Marcelis, L.F.M. ; Kempkes, F.L.K. ; Snel, J.F.H. - \ 2014
    glastuinbouw - cultuurmethoden - phalaenopsis - natuurlijk licht - lichtregiem - lichtsterkte - energiebesparing - schermen - temperatuur - monitoring - greenhouse horticulture - cultural methods - phalaenopsis - natural light - light regime - light intensity - energy saving - blinds - temperature - monitoring
    Natuurlijk licht heeft potentie voor energiebesparing en teeltverbetering. Meer licht in de kas geeft extra groei en bespaart energie en om te voorkomen dat meer licht tot lichtschade leidt, ontwikkelen we ook plantmonitoring. De doelstelling van dit onderzoek is energie besparing, door meer natuurlijk licht, verneveling en aangepaste regeling van temperatuur en scherm.
    Belichtingsapplicatie; een tussenstand
    Gelder, A. de - \ 2014
    glastuinbouw - kasgewassen - belichting - assimilatie - zonne-instraling - lichtregiem - bedrijfsapplicaties - software-ontwikkeling - behoeftenbepaling - greenhouse horticulture - greenhouse crops - illumination - assimilation - insolation - light regime - business software - software engineering - needs assessment
    Assimilatiebelichting op basis van stralingsverwachting en behoefte van het gewas maakt de teler meer bewust van de belichtingsstrategie. Het doel van dit project is de bouw van een applicatie voor advies over belichtingsduur afgestemd op de assimilatenvraag van een gewas en besparing op energie vraag van 10 % voor belichting bij gebruik van de applicatie.
    Stuurlicht Freesia
    Kromwijk, J.A.M. ; Helm, F.P.M. van der - \ 2014
    glastuinbouw - freesia - cultuurmethoden - energiebesparing - lichtregiem - lichtsterkte - gewaskwaliteit - temperatuur - greenhouse horticulture - freesia - cultural methods - energy saving - light regime - light intensity - crop quality - temperature
    Door lage intensiteit stuurlicht in de nacht te combineren met een lagere intensiteit groeilicht overdag dan normaal kan mogelijk dezelfde productie en kwaliteit worden behaald als bij een normaal gangbare hoge intensiteit groeilicht zonder stuurlicht. De doelstelling van dit onderzoek is energiebesparing op elektraverbruik van belichting met behoud van productie en kwaliteit.
    Stuurlicht Sneeuwbal
    Kromwijk, J.A.M. ; Helm, F.P.M. van der - \ 2014
    viburnum - cultuurmethoden - forceren van planten - belichting - led lampen - lichtregiem - gewaskwaliteit - glastuinbouw - viburnum - cultural methods - forcing - illumination - led lamps - light regime - crop quality - greenhouse horticulture
    Bij de vroege trek van sneeuwbal blijft de kwaliteit achter doordat een deel van de bloemknoppen niet of ongelijk uitloopt en de bladkleur lichter is. Doelstelling van dit onderzoek is een uniformere en betere knopuitloop bij vroege trek en kwaliteitsverbetering (betere bladkleur, meer bloemtrossen /tak).
    Marcelis: 'Met lichtintegratie en lagere temperatuur veel te besparen' (interview met Leo Marcelis)
    Arkesteijn, M. ; Marcelis, L.F.M. - \ 2013
    Onder Glas 10 (2013)11. - p. 42 - 43.
    glastuinbouw - potplanten - cultuurmethoden - belichting - temperatuur - lichtregiem - lichtdoorlating - energiebesparing - proeven - greenhouse horticulture - pot plants - cultural methods - illumination - temperature - light regime - light transmission - energy saving - trials
    Binnen het project ‘Grip op licht’ is bij de proef met anthurium en bromelia in het eerste halfjaar gekeken naar het effect van meer licht toelaten als het licht diffuus is. In het tweede halfjaar lag de nadruk bij beide gewassen op de mogelijkheid om ‘s winters energie te besparen door lichtintegratie toe te passen en de teelttemperatuur te verlagen.
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