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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Tomaten telen in een Chinese muurkas, in Nederland en in China
Zwart, Feije de - \ 2018
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport WPR 778) - 26
Gloablly, the largest area of protected cultivation consists of small scale greenhouses growing crops at a low technology level. The Chinese Solar Greenhouse is a good example of such greenhouses. Also in this market, Dutch horticultural and technological knowledge can contribute substantially to an improvement of the cropping result and resource efficiency.This report describes the monitoring of the performance of a tomato crop in a Chinese Solar Greenhouse in the Shandong Province and a comparison with a similar crop in a similar greenhouse in Bleiswijk, the Netherlands. The project is carried out by a consortium consisting of Ludvig Svensson, Ridder–Hortimax, Hoogendoorn, Delphy and Wageningen University & Research, Business unit Glastuinbouw. The project was funded by the Rijksdienst Voor Ondernemend Nederland (RVO) and the Metropole region Rotterdam Den Haag (MRDH).The project has shown that also for simple greenhouses like the Chinese Solar Greenhouse the growth of the crop can be planned as a function of light availability. This analyses showed that the production is likely to be increased by 50% if the growth at the start of the cycle is accelerated. This can be achieved by earlier sowing and using white soil covering foil.
Prei op water : overzicht resultaten 2013 - 2017
Os, E.A. van; Verhoeven, J. ; Wilms, J. - \ 2018
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport Wageningen Plant Research, Business unit Glastuinbouw WPR-764) - 42
Within the 2nd programme Cultivation-out-of-the-soil for field crops (2014-2017) research f°Cussed onoptimisation of the cultivation, sowing on water, the use of a protective tunnel and upscaling. The robustnessof the growing system could be improved by these experiments. Economically the cost of traditional open fieldcropping is almost comparable with the cultivation on water (deep flow technique). In the plant raising stage adecrease in the growing period can be achieved to 60 instead of 84 days. Uniformity is important for a once overharvesting crop but still variation is big, grading of young plants helps a little. Oxygenation of larger ponds isimportant.
De perfecte chrysant teelt 1-4 : energiezuinige demonstratieteelten bij Delphy Improvement Centre
Raaphorst, M. ; Zwart, Feije de; Schuddebeurs, L. ; Veld, Paul de - \ 2018
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport Wageningen Plant Research, Business unit Glastuinbouw WPR-752) - 46
With funding from ‘Kas als Energiebron’, ChrIP and suppliers, four chrysanthemums crops have been carried outat the Delphy Improvement Centre in 2017. These crops had the following targets:• A heat use up to 475 MJ/m2.yr.• This heat must be extracted from harvesting heat (cooling).• A CO2-use of 25 kg/m2.yr.• A yearly electricity usage for lighting of 121 kWh/m2.yr.• 5% more production than professional growers.The most important means to achieve this objective are hybrid lighting, diffuse glass with 2 AR-coatings, anextra energy screen, 8 air handling units, well pumps and a heat pump. The crops are run under the name ‘ThePerfect Chrysanthemum’ (DPC). The realised use of CO2 and heat turn out to be lower than the target. Theamount of heat (cooling) harvested is much higher and the amount of lighting is almost equal to the target.It is concluded that an investment in air handling units, heat pump and source pumps, an extra screen andLED lighting makes it technically possible to grow chrysanthemums without gas, if an alternative is found fordisinfection by steaming.
Lichtmetingen op komkommerbedrijven met LED-tussenbelichting : begeleiden en monitoren van energie-innovaties in de praktijk
Janse, Jan ; Weerheim, Kees ; Dieleman, Anja - \ 2018
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport / Wageningen University & Research, BU Glastuinbouw : WPR-763) - 25
Light interception was measured by Wageningen University & Research Greenhouse Horticulture at two nurseries with cucumbers in a high wire system and a different orientation of the LED-interlighting. The canopy density appeared to be very important for the light interception and up and down light loss. The total light loss to the greenhouse cover and floor was 17 en 34% on both nurseries, respectively. In the middle of the path between crop rows, 17 and 34% of the LED light was still measured, respectively. However, this light will largely be captured by plants of the neighbouring row. The measured interception of the sunlight by the plants, was on both nurseries respectively 96 and 87%. Per 1% additional LED light, a production increase of 0.8% was realised. The project was funded by Kas als Energiebron.
Vergelijking klimaat Paprika : Analyse van Het Nieuwe Telen Paprika bij Delphy Improvement Centre in vergelijking met een praktijkbedrijf
Raaphorst, Marcel - \ 2018
Wageningen : Wageningen University & Research, BU Glastuinbouw (Rapport WPR 747) - 34
The indoor climate, the heat use and the production of a demonstration trial with sweet pepper are compared with a commercial grower. With intensive use of the screens a 59% lower use of heat is achieved. The intensive use of screens has decreased the amount of light with 4% in comparison to the commercial grower. The biggest difference was during the first three (winter) months of cultivation. The roof also showed 4% less light transmission. By dosing 64% less CO2, a lower CO2 concentration was obtained, which should have led to 4% less photosynthesis according to the CO2-rule of thumb. Despite the lower light intensity and lower CO2 concentration, the production was just 10% lower than at the commercial grower. This indicates that CO2 and light have been a little less restrictive than what would be expected from the rules of thumb.
Fytosanitaire na-oogst behandel- en detectietechnieken voor plaagorganismen in tuinbouw
Qiu, Y. ; Hogeveen-van Echtelt, Esther ; Verschoor, J.A. ; Rozen, K. van; Ruizendaal, J.L. ; Helsen, H.H.M. ; Booij, C.J.H. ; Dam, M.F.N. van; Sluis, A.A. van der; Pekkeriet, E.J. ; Vreeburg, P.J.M. ; Vijn, M.P. ; Spoorenberg, P.M. - \ 2018
Wageningen University & Research (Rapport WPR 751) - 81 p.
Klimaat, energieverbruik en bloem temperatuur bij twee Gerbera telers : als onderdeel van het monitoringsproject
Vanthoor, B.H.E. ; Tsafaras, I. - \ 2018
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport / Wageningen University & Research, BU Glastuinbouw WPR-741) - 38
This report provides an overview of the Gerbera companies -Holstein Flowers and Zuijderwijk Witzier. Both growers have a blackout screen, energy screen and an illumination system. Holstein Flowers dehumidifies the greenhouse air by means of blowing in heated outside air (using air ducts) and Zuijderwijk Witzier uses a Ventilation Jet system. Both growers screen a lot using a screen gap and they close very rare the screens for 100%. At Holstein Flowers the calculated energy consumption is 22.7 m3/m2/year and at Zuijderwijk 23.8 m3/ m2/year. With a thermal camera, the crop and flower temperatures were measured and they were rarely below the dew point. By carrying out plant sap analyses at 4 growers, a statistical relationship between the plant sap composition and the chance of rot heads (‘rotkoppen’) has been demonstrated. However, it is unknown whether this relationship is also a causal relationship, other factors could also have caused the rot heads. If the mechanism behind the development of Botrytis/rot heads were known, then a grower could - depending on the plant balance, evaporation and the chance of getting Botrytis/rot heads –grow with lower moisture deficits, which could then lead to energy savings
Vergelijking tomatenteelten met een Ventilation Jet systeem : als onderdeel van het monitoringsproject
Vanthoor, B.H.E. ; Tsafaras, I. - \ 2018
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport / Wageningen University & Research, BU Glastuinbouw WPR-744) - 26
De belichte tomatenbedrijven Greenco en Gardener’s Pride telen een kleine tomaat en zijn uitgerust met een: Ventilation Jet (VJ) systeem, SON-T belichting systeem, verduisteringsscherm en een energiescherm. Het berekende energieverbruik wat via de buizen bij Gardener’s Pride de kas in was gebracht was tussen 1 december 2016– 1 december 2017 37.8 m3/m2/jaar en bij Greenco 25.4 m3/m2/jaar. Het hogere energieverbruik bij Gardener’s Pride kon verklaard worden doordat: (1) Sunstream een ras is dat generatief gestuurd wordt; (2) Gardener’s Pride niet zo’n hoge relatieve vochtigheden durfde aan te houden door het ontbreken van het werkende VJ systeem en (3) Gardener’s Pride minder heeft geschermd. Met de Ventilation Jets waren de tuinders goed in staat om het verduisteringsdoek (bijna) 100% gesloten te houden op momenten dat er belicht werd. Gedurende bepaalde periodes hebben beide tuinders besloten om het Ventilation Jet systeem minder te gebruiken. De telers hebben het vermoeden dat de luchtbeweging die veroorzaakt wordt door de recirculatieventilator soms zorgt voor een te generatieve gewasreactie. Bij Gardener’s Pride bleek dat nog geen 3% van de lucht die ingeblazen wordt door de VJ, de kas verlaat via de kier op het middenpad. Onder deze omstandigheden kan dus geconcludeerd worden dat deze kier niet nodig is---The tomato companies Greenco and Gardener’s Pride grow a small tomato and are equipped with a: Ventilation Jet (VJ) system, SON-T lighting system, blackout screen and an energy screen. The energy consumption that was brought into the greenhouse by the heating pipes at Gardener’s Pride was 37.8 m3/m2/year between 1 December 2016 and 1 December 2017 and 25.4 m3/m2/year at Greenco. The higher energy consumption at Gardener’s Pride could be explained by: (1) Sunstream is a variety that is grown very generative; (2) Gardener’s Pride did not dare to hold high relative humidity levels due to the lack of a working VJ system and (3) Gardener’s Pride had fewer screening hours. Thanks to the Ventilation Jets, the growers were able to keep the blackout screen (almost) 100% closed at times when the lighting system was on. During certain periods both growers have decided to use the Ventilation Jet system less. The growers suspect that the air movement caused by the recirculation fan ensures sometimes undesired extra generativity. At Gardener’s Pride, it turned out that less than 3% of the air blown in by the VJ leaves the greenhouse through the gap at the central path. It can therefore be concluded that under these circumstances this gap is not necessary
Ervaringen met het Ventilation Jet systeem bij Dekker Chrysanten : als onderdeel van het monitoringsproject
Vanthoor, B.H.E. ; Tsafaras, I. - \ 2018
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport / Wageningen University & Research, BU Glastuinbouw WPR-743) - 22
The purpose of the Ventilation Jet (VJ) system at Dekker Chrysanten is to reduce the temperature of the grow pipe in order to save energy. Dekker Chrysanten encountered problems with circles in the crop in the VJ compartment in many cultivation rounds in 2016 and 2017. Early flowering took place at these circles, which occasionally resulted in poorer quality and shorter stems. Due to these cultivation problems, Dekker Chrysanten did not want to reduce yet the minimum grow pipe in the Ventilation Jet compartment. Due to the efforts of the growers and the monitoring project, potential causes have been identified and solved such as (1) the prevention of dry spots in the soil by: switching off the VJ when there is irrigation, switching on the VJ later in the short day period and by irrigating more (this is done companywide); (2) lowering the relative humidity setpoint in the VJ compartment at night so that a higher night evaporation is achieved; (3) improving the air flow profile of the bottom fan and (4) adjusting the climate computer software, resulting in a much more stable temperature and RH in the VJ compartment. The above learning experiences are now applied which has resulted in a good quality chrysanthemum in the past cultivation period (harvest January 2018).
Perchloraat in kasgrond Bioteelt : Resultaat uitspoelproef voor vermindering perchloraat concentratie in de biologische kasteelt
Voogt, Wim ; Winkel, Aat van - \ 2018
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport WPR 765) - 22
certain fertilisers. This ion can be taken up by plants quite easily and will be transported partly into fruits, hence the norms for ClO4 - will be exceeded easily. Experiments have been carried out to leach out the soil by flushing. It appeared that ClO4 - can be leached out quite easily, but it requires a lot of water and the strategy has to be adapted to the soil type.
Precisietechnologie Tuinbouw: PPS Autonoom onkruid verwijderen : D2.4 Literatuurstudie spectrale reflectie-eigenschappen van planten en onkruiden; D2.5 Lab en veldexperimenten spectrale reflectie-eigenschappen van planten en onkruiden
Blok, Pieter ; Hemming, Jochen ; Holterman, Henk-Jan ; Michielsen, Jean-Marie ; Ruizendaal, Jos - \ 2018
Bleiswijk : Wageningen Plant Research, Business unit Glastuinbouw (Rapport WPR 751) - 118
This report contains the two deliverables of the research project “autonomous weed removal” that deal with the topic hyper- and multispectral weed detection. In the literature of the past 10 to 15 years, there are sufficient indications that a good distinction on the basis of spectral characteristics can be made between various plant species. For the hyperspectral lab measurements, various crops and weeds have been cultivated. The reflection spectrum of all plants was measured between 400 and 1000 nm and between 900 and 1700 nm on different growing stages in the laboratory. In particular the reflection in the chlorophyll range (650-670 nm) and in the green range (around 550 nm), red-edge (700 nm) and near-infrared (800 nm) show a distinctive power between the crops and weeds studied. With field measurements it was investigated whether it is possible to detect green weeds in a green lettuce crop using hyperspectral camera images. The accuracy of a correct classification on both measurement days was 6.9% and 9.9%, respectively, below the previously set target value of 90%. In order to exclude the effect of the use of different cameras on the test result, a comparative follow-up study is recommended.
Precisietechnologie Tuinbouw: PPS Autonoom onkruid verwijderen : Eindrapportage
Hemming, Jochen ; Blok, Pieter ; Ruizendaal, Jos - \ 2018
Bleiswijk : Wageningen Plant Research, Business unit Glastuinbouw (Rapport WPR 750) - 42
Work package 2 of the Precision Technology Horticulture program focuses on autonomous weed removal. This final report contains four deliverables: D2.1 Module for recognition of red lettuce, D2.2 Vision based crop row guidance module, D2.3 Machine for hoeing more than 8 crop rows simultaneously, and D2.6 Actuator for controlling weeds in full field crops. D2.1 reports on the software for an extra colour segmentation algorithm that has been added to the Steketee IC-cultivator. With this algorithm it is possible to adequately detect and distinguish non green plants, such as red lettuce, from weeds. For D2.2 a standalone module for crop row guidance for hoeing between the row has been developed. D2.3 describes is the extension in hardware and software that makes it possible to hoe up to 24 crop rows simultaneously. For D2.6, research has been conducted into different robotic arms to move the end effector to the right spot for weed control in full field crops. Different arms are compared and the maximum possible driving speed was be calculated. A test device for full field weed control was build based on a x-z position unit. The chapter publications and media provides an overview of the dissemination of the project results throughout the duration of the project.
Voorkomen en bestrijden emissies kasteelten : Fase I: 2017
Beerling, Ellen ; Blok, Chris ; Cornelissen, Emile ; Eveleens-Clark, Barbara ; Gozales, Jorge ; Harmsen, Danny ; Koeman, Nienke ; Leyh, Romain ; Os, Eric van; Palmen, Luc ; Roest, Els van der; Ruijven, Jim van; Stijger, Ineke ; Voogt, Wim - \ 2018
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport WPR 748) - 46
In this project, solutions are developed to minimise leaching of nutrients and pesticides from greenhouses to the environment (esp. surface water), in order to comply with legislation and societal demands. In 2017 the following questions have been addressed: To prevent emission, drain solutions are reused or purified. Other water flows may deviate in compositionand possibilities for reuse or purification. The option for reuse or purification for these water flows has been investigated, and a working methodology for the end of a cultivation (e.g. cleaning) has been developed. Applications of Forward Osmosis in horticulture have been investigated. Water extracted from the discharge flow with Forward Osmosis using the concentrated nutrient solution holds prospects, but extracting irrigation water from brackish groundwater seems less feasible. In a long-term experiment, sodium (Na) standards for sweet pepper have been reinterpreted. It was shown that an increase in the Na standard up to 8-10 mmol/l causes no damage or loss in pepper production. Inaddition, it was shown that the split-root system can be used for uptake of extra Na without growth hampering. Furthermore, applying humate can prevent negative sodium effects at high sodium levels (Chinese cabbage). Finally, insight was gained into the risks associated with the use of chlorinated cleaning products in zero-discharge cultivations.
Programmeringsstudie Meeldauw : Invloed van bestaande en nieuwe interventies op geïnduceerde weerbaarheid tegen biotrofe schimmel
Hofland-Zijlstra, J.D. ; Breeuwsma, S. ; Noordam, M. ; Stevens, L. - \ 2018
Bleiswijk : Wageningen University & Research, Business unit Glastuinbouw, (Wageningen Plant Research rapport WPR-749) - 46
Purpose of this TKI project Programming study powdery mildew is to generate new knowledge about existingand new interventions aimed at prevention of mildew development in horticultural crops. This research isconducted by Wageningen University & Research greenhouse horticulture business unit. The project is supportedby LTO Glaskracht Nederland. To test the impact of existing interventions on the natural defenses of a plant testsin climate chamber were carried out with total daylight sum, CO2 and relative humidity. After three weeks theinfluence on the production of pathogen related proteins, which is a measure for induced resistance, was veryminor. However, it is confirmed that relative humidity and the daily light sum influence the mildew developmentdirectly and to a higher extent than the CO2. In addition, changes in nutritional composition of plants may be oneof the first indicators for enhanced disease risk (e.g. sodium).
Het winterlicht gewas : proof off principle met komkommer
Kempkes, Frank ; Meinen, Esther ; Janse, Jan ; Elings, Anne ; Visser, Pieter de; Raaphorst, Marcel ; Vukadinovic, Danijela - \ 2018
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Wageningen University & Research, BU Glastuinbouw rapport WPR-725) - 58
In de winter is licht in Nederland voor vrijwel alle gewassen de limiterende factor voor de productie. In de zoektocht naar het maximaal gebruik maken van het beperkte licht in de wintermaanden is het belangrijk het licht zo optimaal mogelijk om te zetten in gewasproductie. Om de mogelijkheden beter in kaart te brengen, is in aansluiting op de opgedane kennis in het project ‘Verbetering lichtinval winterlicht’, waar de lichttoetreding door het kasdek is geoptimaliseerd voor de wintermaanden. In dit project is de gewaskant aan bod gekomen. Het werk in dit project is gefinancierd door het onderzoeksprogramma Kas Als Energiebron. Dit onderzoeksprogramma is een samenwerkingsverband tussen het ministerie van Landbouw, Natuur en Voedselkwaliteit en LTO-Glaskracht Nederland. Voor maximalisatie van de lichtonderschepping is een oost-west pad richting de eerste stap. De raseigenschappen van het gekozen komkommer ras vragen door de variatie in bladafmeting tijdens de teelt van groot naar klein een adaptatie van het gewasmanagement aan de veranderende plantvorm in de tijd. Een smalle gootafstand om hier eenvoudig op in te spelen blijkt te veel gewasbeschadiging op te leveren. De beste resultaten kwamen naar voren bij de grootste gootafstand
Luchtzuivering door kamerplanten : een literatuurstudie
Visser, Pieter de - \ 2018
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Wageningen University & Research, BU Glastuinbouw rapport WPR-695) - 26
Within the project ‘Plant champion air purification’, a public-private cooperation within Topsector Horticulture and Starting materials, a literate survey was carried out by WUR Greenhouse Horticulture to explore recent findings on the possibilities of plants to purify indoor contaminated air. Literature was searched in academic journals, on the internet and within reports recently carried out for the horticultural sector. Here this knowledge is shortly described. Plants generally have the capacity to assimilate hydrophilic Volatile Organic Compounds (VOCs) like formaldehyde without harm. Lipophilic VOCs are less well assimilated and follow different uptake pathways. Differences between plant species can sometimes be related to amount of leaves, wax layer composition, stomatal conductance or hairs. Apart from the green plant parts, the roots, the micro-organisms and rooting medium have a role in air purification. The research in plant chambers mainly generated knowledge on short term uptake of volatiles, but the uptake mechanisms and the long-term performances of plants are only partly understood. The research on upscaling of lab results to air purification in rooms within buildings is currently rapidly evolving. A few good studies have been done and show promising results. More research is needed to extrapolate the findings from lab research to practice in a reliable way
Feasibility study thin glasses for greenhouse roof designs
Hemming, Silke ; Mohammadkhani, Vida ; Kempkes, Frank ; Peters, Anton ; Lieffrig, Vincent ; Harada, Keitaro ; Spronsen, Michiel van; Werff, Tjibbe van der; Louter, Christian - \ 2018
Bleiswijk : Wageningen University & Research, BU Greenhouse Horticulture (Wageningen University & Research, BU Greenhouse Horticulture report WPR-732) - 50
In this study, the feasibility of the application of flexible thin glass in greenhouses was investigated. With the development of thin but very strong glass plates like for mobile phones, new possibilities are being created for new greenhouse roof designs, the usage in multi-layered glass roof give possibilities for high-insulation greenhouse coverings. Flexible thin glass is a tempered glass. While standard tempered glass goes through a thermal process, this is a chemical process, which makes the glass five times stronger, creating the possibility of thickness reduction and bending. By adding nanocoatings the reflection can be reduced and the light transmission can be increased. Multi-layered greenhouse roofs can be created, resulting in a higher light transmission than currently available multilayer polycarbonate (PC) sheets, but also a higher transmission than today’s insulating double glass. The study shows that such glass combinations lead to an additional 20% energy savings based on heat demand for Phalaenopsis. Thin glasses are particularly strong and can also be used in curved form. This makes new greenhouse roof designs with these glasses possible. Especially the low weight offers advantages here. Important mechanical aspects and bottlenecks for the use in greenhouses have been mapped out. Due to limitations in today’s available dimensions and high prices, the use of thin glass in greenhouses will be further away in the future
Integrated pest management component of the Ethio-Dutch Program for Horticulture Development : contribution of Wageningen University and Research - final report
Elings, Anne ; Messelink, Gerben ; Kruidhof, Marjolein ; Leman, Ada ; Cuesta Arenas, Yaite ; Wurff, Andre van der - \ 2018
Bleiswijk : Wageningen University & Research, BU Greenhouse Horticulture (Wageningen University & Research, BU Greenhouse Horticulture report WPR-711) - 114
The Ethiopian Horticulture Producer Exporters Association (EHPEA) is responsible for the Ethio-Dutch Program for Horticulture Development (EDPHD). One of the components of this program is the Integrated Pest Management (IPM) which has been executed by Wageningen University and Research, Business Unit Greenhouse Horticulture in collaboration with Ethiopian research organizations and EHPEA. This final report of the WUR team reports on the following project activities: 1) Technical advice on formulation of the best microbial bca’s obtained from the conducted research, 2) Survey, collection and commercialization of indigenous natural enemies for the management of major horticultural pests, 3) Support and advice on the study of the biology of identified potential indigenous natural enemies, 4) Support and advice on small-scale mass production for evaluation trials and methods to establish persistent populations in crops, 5) Technical advice on the efficacy trials under laboratory and field conditions on the identified predators and parasitoids, 6) Review of IPM course delivered at Jimma University, 7) Sharing information with growers and companies, 8) Train the trainer, and 9) All collection and other missions
Natriumgevoeligheid en recirculatie bij Cymbidium in 3 teeltjaren : Behoud plantgezondheid en voorkomen groeiremming bij hergebruik drainwater
Kromwijk, Arca ; Voogt, Wim ; Steenhuizen, Johan ; Winkel, Aat van; Mourik, Nico van - \ 2017
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport WPR 735) - 54
In the Netherlands, the government and horticultural industry have agreed to lower the emission of nutrients to the environment. Until recently no drain water was reused in the cultivation of Cymbidium orchids as growers were allowed to discharge the drain water when a sodium level of more than 0 mmol/l was reached. As reusing drain water is a new phenomenon for Cymbidium, growers were faced with a lack of knowledge on the effects of drain water reuse. Therefore a trial was started to investigate the effect of sodium accumulation on crop growth and flowering in two varieties of Cymbidium. Different sodium concentrations are given while maintaining the EC at 0.8. These sodium treatments have a lower “nutritional EC” than the control treatment without sodium. In the first year of cultivation unusual symptoms in the leaves emerged at the two highest levels of sodium resulting in dead leaf tips / leaves. This is potassium deficiency, induced by the lower potassium concentration in the nutritional solution and by inhibition of the potassium uptake by a high sodium concentration. In the first year of cultivation, sodium accumulation had no effect on production as the flower stalks were already induced before or just after the start of the treatments. In the second and third year of cultivation, sodium accumulation reduced production and quality of Cymbidium. This research is funded by the Cymbidium growers in the Netherlands, Product Board for Horticulture, Top Sector Horticulture & Propagation Materials and Foundation Program Fund Greenhouse Horticulture.
Vermindering emissie van meststoffen met controlled released fertilizers (CRF) bij potorchidee (Phalaenopsis)
Kromwijk, Arca ; Haaster, Bram van; Steenhuizen, Johan - \ 2017
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport WPR 703) - 46
In the Netherlands, the government and horticultural industry have agreed to lower the emission of nutrients to the environment. Previous research in pot orchid cultivation research showed that the reuse of drain water can lower the emission of nutrients significantly and had no adverse effects on plant growth or disease incidence. For further reduction of the emission of nutrients research into the effects of controlled released fertilizers (CRF) and reusing drain water (recirculation) in Phalaenopsis was conducted at Wageningen University & Research, Business Unit Greenhouse Horticulture in Bleiswijk. Two treatments with CRF were compared with a treatment without CRF with reusing drain water. The EC in the drain water of the treatments with CRF was 30% to 60% lower and the total amount of N in the drain water was 40 to 75% lower than in the treatment without CRF. This research is funded by the Phalaenopsis growers in the Netherlands, ICL Specialty Fertilizers, Top Sector Horticulture & Propagation Materials and Foundation Program Fund Greenhouse Horticulture.
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