Records 1 - 20 / 2899
Mobiele waterzuivering glastuinbouw
Ruijven, Jim van; Os, Erik van; Vermeulen, Peter - \ 2017
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport GTB 1424) - 54
kassen - glastuinbouw - afvalwaterbehandeling - afvalwater - waterverontreiniging - afvoer - zuiveren - waterzuivering - oppervlaktewater - oppervlaktewaterkwaliteit - gewasbescherming - pesticiden - substraten - cultuur zonder grond - mobiele uitrusting - greenhouses - greenhouse horticulture - waste water treatment - waste water - water pollution - discharge - purification - water treatment - surface water - surface water quality - plant protection - pesticides - substrates - soilless culture - mobile equipment
Application of a mobile unit for discharge water purification is one of four options to apply to the purification obligation per 1-1-2018. Depending on the amount of discharge, future water strategy and investment options, mobile purification can be an interesting option. The amount of discharge water varies with crop, irrigation strategy and quality of the irrigation water and is between 122 and 3.340 m3/ha/year for surveyed companies. About 65% of greenhouse companies discharges
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 - fusarium - 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 door lokale verwarming : test op teelttafels bij Elstgeest Potplanten
Raaphorst, Marcel ; Noort, Filip van - \ 2017
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport GTB 1439) - 18
kasgewassen - glastuinbouw - kassen - dieffenbachia - potplanten - sierplanten - verwarming - verwarmingssystemen - energiebesparing - greenhouse crops - greenhouse horticulture - greenhouses - dieffenbachia - pot plants - ornamental plants - heating - heating systems - energy saving
On a pot plant nursery three cultivation tables are heated directly with mat heating and one cultivation table is heated indirectly with tube heating. At these four tables the effect is measured on the air temperature below the table, the pot temperature, the energy use and the crop growth of Dieffenbachia. The conclusion is, that with mat heating a lower air temperature can be held under cultivation table to achieve a certain pot temperature. It is estimated that with this lower air temperature 10-30% of heat is saved because less heat disappears to the soil. For Dieffenbachia, the greenhouse air temperature above the pot is more determining for crop development than the pot temperature is. It is expected, that the energy-saving effect of mat heating is larger for plants with a low growth point, for which the pot temperature has more effect on growth.
Systeemstap naar minimaal energieverbruik Alstroemeria : metingen op praktijkbedrijven en een energiezuinige teeltconcept
Garcia Victoria, N. ; Zwart, Feije de; Weel, Peter van; Steenhuizen, Johan ; Groot, Marco de - \ 2017
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport GTB 1372) - 66
kasgewassen - glastuinbouw - kastechniek - kassen - alstroemeria - energiebehoeften - energiebesparing - verwarming - aanvullend licht - kunstlicht - simulatiemodellen - isolatie (insulation) - evaporatie - greenhouse crops - greenhouse horticulture - greenhouse technology - greenhouses - alstroemeria - energy requirements - energy saving - heating - supplementary light - artificial light - simulation models - insulation - evaporation
Alstroemeria cultivation in The Netherlands requires energy for heating, supplementary light and root cooling. For the program “Greenhouse as Source of Energy” we calculated to which extent the energy demand for growing this crop can be reduced with existing energy saving innovations. Some innovations were tested in practice, others were calculated by means of the greenhouse climate simulation model Kaspro. Results showed that it is possible to save up to 34% energy for heating compared to the reference situation. 40% energy can be saved on electricity for supplementary light and root cooling. However, this strategy leads to a reduced amount of PAR-light in the winter, and 4% less flowers in comparison with the reference. The greatest impact can be achieved by increasing the insulation of the greenhouse by using double screens, reducing the evaporation from the soil, improving the crop hygiene to avoid extra evaporation from crop debris and reduce pest pressure, and implementing controlled dehumidification of the greenhouse air.
Ontwikkeling teeltstrategie voor weerbare planten tegen bovengrondse ziekten
Hofland-Zijlstra, J.D. ; Breeuwsma, S. ; Noordam, M. - \ 2017
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport GTB 1442) - 58
kasgewassen - glastuinbouw - geïntegreerde plagenbestrijding - gewasbescherming - schimmels - schimmelziekten - botrytis - schimmelelicitoren - elicitoren - greenhouse crops - greenhouse horticulture - integrated pest management - plant protection - fungi - fungal diseases - botrytis - fungal elicitors - elicitors
Within a project Sustainable control strategies Wageningen University & Research Greenhouse Horticulture literature screening to develop an integrated pest management strategy to control airborne fungi. This project was funded by the former Dutch Horticultural Production Board and accompanied by the Dutch growers association, LTO Glaskracht Nederland. In 2016 two greenhouse trials were performed with pot tomato, Petunia and pot gerbera. Additionally, a greenhouse test was performed at a commercial greenhouse with pot gerbera. Goal was to test the side effects of synthetic elicitors which stimulate systemic acquired resistance against biotrophic fungi on disease resistance against nectrotrophic fungi like Botrytis. A commercially available synthetic elicitor, Fado (Nufarm) was able to reduce the Botrytis infection in pot tomato and in flowers of pot gerbera. Effectivity was supported by a combined treatment with Jiffy mineral (soil addition) and Serenade. Two experimental products of BASF and Nufarm were effective in reducing Botrytis in pot gerbera. Botrytis infection was not only related to light and relative humidity, but was also correlated with nutrients and chlorophyll content. Based on this knowledge, prediction models for Botrytis can be improved.
Crop growth and development in closed and semi-closed greenhouses
Qian, Tian - \ 2017
Wageningen University. Promotor(en): L.F.M. Marcelis, co-promotor(en): J.A. Dieleman; A. Elings. - Wageningen : Wageningen University - ISBN 9789463430708 - 112
crops - crop production - growth - greenhouse crops - greenhouse horticulture - climate - semi-closed greenhouses - photosynthesis - temperature - gewassen - gewasproductie - groei - kasgewassen - glastuinbouw - klimaat - semi-gesloten kassen - fotosynthese - temperatuur
(Semi-)closed greenhouses have been developed over the last decades to conserve energy. In a closed greenhouse, window ventilation is fully replaced by mechanical cooling while solar heat is temporarily stored in an aquifer. A semi-closed greenhouse has a smaller cooling capacity than a closed greenhouse and, in which mechanical cooling is combined with window ventilation. (Semi-)closed greenhouses create new climate conditions: high CO2 concentrations irrespective of the outdoor climate, and vertical gradients in temperature and vapour pressure deficit throughout the canopy. This thesis focuses on the crop physiology in (semi-)closed greenhouses, and investigates the effects of the new climate conditions on crop growth, development and underlying processes.
Cumulative production in (semi) closed greenhouses increased by 6-14% compared to the open greenhouse, depending on the cooling capacity. The production increase in the (semi-)closed greenhouses was explained by the higher CO2 concentrations. In many species, feedback inhibition of photosynthesis occurs when plants are grown at high CO2. The results, however, suggest that high CO2 concentrations do not cause feedback inhibition in high producing crops, because the plants have sufficient sink organs (fruits) to utilise all assimilates. Pruning experiments showed that photosynthetic acclimation to elevated CO2 concentration only occurred when the number of fruits was considerably reduced.
Cooling below the canopy induced vertical temperature and vapour pressure deficit gradients. These gradients correlated with outside radiation and outside temperature. Despite the occurrence of vertical temperature gradients, plant growth and fruit yield were mostly unaffected. Leaf and truss initiation rates did not differ in the presence or absence of a vertical temperature gradients, since air temperatures at the top of the canopy were kept comparable. The only observed response of plants to the vertical temperature gradient was the reduced rate of fruit development in the lower part of the canopy. This resulted in a longer period between anthesis and fruit harvest and an increase in the average fruit weight in summer. However, total fruit production over the whole season was not affected.
The effects of the climate factors light, CO2 concentration, temperature, and humidity on leaf photosynthesis were investigated. The photosynthesis model of Farquhar, von Caemmerer and Berry (FvCB) was modified by adding a sub-model for Ribulose-1,5-bisphosphate carboxylase (Rubisco) activation. The photosynthetic parameters: the maximum carboxylation capacity (Vcmax) and the maximum electron transport rate (Jmax), α (the efficiency of light energy conversion), θ (the curvature of light response of electron transport), and Rd (the non-photorespiratory CO2 release) were estimated based on measurements under a wide range of environmental conditions in the semi-closed greenhouse. The simultaneous estimation method and the nonlinear mixed effects model were applied to ensure the accuracy of the parameter estimation. Observations and predictions matched well (R2=0.94).
The yield increase in a closed greenhouse, compared to that in an open greenhouse was analyzed based on physiological and developmental processes. The yield increase in the (semi-)closed greenhouses was the result of an increase of net leaf photosynthesis. The (semi-)closed greenhouses have been applied commercially first in the Netherlands, and later in other countries. The knowledge obtained from (semi-)closed greenhouses is applied in conventional open greenhouse as well, which is called the next generation greenhouse cultivation. A number of innovations are being developed for greenhouse industry to reduce energy consumption while improving production and quality.
Paprikateelt in de hooggeïsoleerde VenLow Energy kas
Zwart, H.F. de; Gelder, A. de; Hofland-Zijlstra, J. ; Noordam, M. - \ 2017
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport GTB 1435) - 34
paprika's - capsicum annuum - kassen - kasgewassen - glasgroenten - glastuinbouw - energiebesparing - energiegebruik - isolatie (insulation) - broeikasgassen - kooldioxide - sweet peppers - capsicum annuum - greenhouses - greenhouse crops - greenhouse vegetables - greenhouse horticulture - energy saving - energy consumption - insulation - greenhouse gases - carbon dioxide
In order to realise a horticultural sector that operates without the combustion of fossil fuel, the first step is to reduce the demand for heating by improving the insultation of greenhouses. This holds especially for crops that are grown at high temperatures, like sweet pepper. The Venlow Energy greenhouse with its double glass cladding and energy screen is a good example of such a highly insulated greenhouse. This report presents the results of a one year cultivation and serves as a bench mark for the state of the art in energy conserving production of Sweet Pepper in the Netherlands. It shows the greenhouse climate conditions required, and the possibilities to meet these requirements with a low energy consumption and options to realise this from sustainable sources. The application of sustainable energy sources was not tested in practice, but since the exact resources (heat and CO2) required from hour to hour were measured, it is easy to do the math on the amounts and capacities needed. The application of pure CO2 or CO2 from another sustainable source is essential when aiming at a fossil energy free horticulture. Without external CO2 the production will drop substantially, especially because an energy conserving greenhouse has typically a strongly reduced air exchange. But, for the same reason, the amount of CO2 needed to increase the CO2 concentration is quite limited, 25 kg/m² per year in this experiment. With a production of 32.5 kg class I of red Sweet Pepper per m², the experiment has shown that halving the energy consumption compared to the general practice did’nt reduced the production.
Teelt Gerbera in Balans : de invloed van lichtsom, etmaaltemperatuur en daglengte op productie, energiegebruik en plantbalans
Garcia Victoria, Nieves ; Gelder, Arie de; Kempkes, Frank ; Dings, Eugenie - \ 2017
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport GTB 1417) - 102
glastuinbouw - kasgewassen - kassen - gerbera - energiegebruik - kooldioxide - kunstlicht - gewaskwaliteit - productie - greenhouse horticulture - greenhouse crops - greenhouses - gerbera - energy consumption - carbon dioxide - artificial light - crop quality - production
“Gerbera: Growing in Balance” was a research project to support the reduction of energy and CO2 consumption in the cultivation of Gerbera. The varieties Pre-Semmy, Rich, Whisper and Suri were grown in three glasshouses with different treatments: “Cool Cultivation” (15°C temperature; 90 μmol light, day length 13 hour in winter); “Practice” (temperature depending on day light integral, 100 μmol/m2s light, day length 11.5 hours) and “Light Dependent” (temperature depending sharply on day light integral, 90 μmol/m2s light, day length 13 hours in winter). The day light integral was kept equal in all treatments, regardless the difference in light intensity and day length in the winter. For flower quality and energy use “Cool Cultivation” was the best treatment, but required the most kg / m² of CO2. Whisper and Suri produced more flowers / m2 in the treatment “Light Dependent” but flower weights were low. Pre-Semmy and Rich gave more flowers in the treatment “Practice”, but spalkes were weak in May and June. The 13 hour day length in winter was not detrimental to production or quality. Light sum, day length and daily temperature are the three buttons to control the plant balance for optimum production and quality. The project was Funded by the Program “Greenhouse as Energy Source” (Ministry of Economic Affairs and LTO Glaskracht) and the Knowledge Cooperative Gerbera.
Overzichtsdocument: 7 jaar Chrysant op water
Vermeulen, Tycho ; Blok, Chris ; Eveleens, Barbara - \ 2017
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport GTB 1430) - 22
greenhouse crops - greenhouse horticulture - greenhouses - chrysanthemum - hydroponics - water systems - microbial contamination - inoculation - kasgewassen - glastuinbouw - kassen - chrysanthemum - hydrocultuur - watersystemen - microbiële besmetting - inoculatie
Over a period of seven years (2009-2016) hydroponic chyrsanthemum cultivation has been developed and
tested in practice. Where the system delivered up to 25% higher yields at smaller scale, the larger systems of
250-300 m2 turned out very sensitive to root infection. Research then focussed to understanding the key factors
that caused the plants to become sensitive. However, where the larger system showed much disease incidence
every summer for three years in a row, at smaller scale the symptoms could not be induced despite application
of extreme cultivation measures.
The studies were the first to apply next generation sequencing to microbial populations in cultivation systems.
The results gave evidence for shifting population dynamics due to inoculation and water temperature. Also the
inoculation with beneficial microbes was found to have a positive effect on recovery of the roots upon infection.
This effect, however, was only found in the research-facility. At larger scale potential beneficial effect could not
prevent significant yield loss.
Nieuwe methoden in plantversterking tegen ondergrondse ziekten en plagen : gebruik van lokaal aanwezige antagonisten uit groeisubstraat en plant
Wurff, Andre van der; Streminska, M.A. ; Boer, F.A. de; Bruyant, Ewen ; Cuesta Arenas, Y. - \ 2016
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport GTB 1427) - 42
kasgewassen - kassen - glastuinbouw - gewasbescherming - plantenziekteverwekkers - antagonisten - bacteriën - verdediging - verdedigingsmechanismen - endofyten - pythium ultimum - meloidogyne - rhizobium rhizogenes - fusarium oxysporum - fusarium - micro-organismen - proteïnaseremmers - bèta-glucanase - chitinase - greenhouse crops - greenhouses - greenhouse horticulture - plant protection - plant pathogens - antagonists - bacteria - defence - defence mechanisms - endophytes - pythium ultimum - meloidogyne - rhizobium rhizogenes - fusarium oxysporum - fusarium - microorganisms - proteinase inhibitors - beta-glucanase - chitinase
Within this project, two new methods of the control of pathogens were investigated. New methods are: a. use of local bacteria that are isolated from soils or growing substrates; and b. bacteria that are present within the plant. By using local antagonists, already present in growing substrates or within plants in the greenhouse, the chance is higher that antagonist can be successfully used against local pathogens. Bacteria that were isolated from soil of growers were assessed on their antagonistic potential in lab trials against Pythium ultimum, Meloidogyne spp. and Rhizobium rhizogenes and Fusarium solani and F. oxysporum. Finally, the effect of antagonists against Pythium and Meloidogyne was evaluated in pot trials in the greenhouse. All antagonists diminished brown colourization symptoms in stems caused by Pythium. Alcaligenues sp., Bacillus sp. en two unidentified species diminished root damage and Alcaligenues sp. as well as Bacillus also reduced also the number of offspring of Meloidogyne spp. within the roots. The use of local microorganisms offers a sustainable-, new solution to control pathogens. In this study, it was shown that Proteinase inhibitor 2 (PINII), Glucanase (LeGluB) and Chitinase (LeChi3) can be used in tomato to investigate the influence of antagonists or endophytes on the plant defence.
Ruijven, J. van; Os, E. van; Beerling, E. ; Staaij, M. van der - \ 2016
Bleiswijk : Wageningen UR Glastuinbouw (Rapport GTB 1419) - 42
kasgewassen - kassen - glastuinbouw - afvoer - zuiveren - gewasbescherming - ozon - greenhouse crops - greenhouses - greenhouse horticulture - discharge - purification - plant protection - ozone
To apply to the Dutch generic obligation to purify discharge water, each horticultural company needs to treat it’s discharge water with a technology that removes 95% of plant protection products. This report shows the process that growers need to go through to make a good choice for a purification technology: mapping of water flows, decrease the amount of discharge water, determine the strategy to apply to the generic obligation and make a choice for a purification technology. For a cucumber production company and a company that combines vegetable plant propagation and growth of potted plants this process is followed. A design for a purification system is developed and built for a semi-practice scale cucumber and sweet pepper production system. In the semi-practice scale and the cucumber production company, an ozone installation (Agrozone) is chosen, either to disinfect drain water and eventually purify discharge water. At the propagation company, an Opticlear Diamond (WaterIQ) is chosen to disinfect the drain water and eventually purify discharge water. For both installations the purification efficacy is measured. In the second part of the project the practical format for the generic obligation for discharge water purification is elaborated.
Optimale assimilatie eerste vereiste voor goede bloemkleuren : kleur afhankelijk van pigmenten en celstructuur
Heuvelink, E. ; Kierkels, T. - \ 2016
Onder Glas 13 (2016)11. - p. 14 - 15.
bloemen - bloementeelt - glastuinbouw - plantkunde - kleur - pigmenten - flowers - floriculture - greenhouse horticulture - botany - colour - pigments
Oorspronkelijk zijn bloemkleuren vooral van belang om bestuivers te lokken, maar in de bloemisterij is dat juist niet gewenst. Daar staat de aantrekkelijkheid voor de koper voorop. Er is voortdurend behoefte aan nieuwe spannende kleuren. Bloemkleur is daarmee een economische factor van belang. Veredelaar maar ook teler kunnen het verschil maken.
Geïntegreerde bestrijding van plagen in de sierteelt onder glas : een systeembenadering met preventieve biologische bestrijding als basis
Messelink, G.J. ; Leman, A. ; Ghasemzadeh Dizaji, Somaiyeh ; Bloemhard, C.M.J. ; Holstein, R. van; Vijverberg, Roland ; Muñoz-Cárdenos, Karen - \ 2016
Bleiswijk : WageningenUR Glastuinbouw (Rapport GTB 1420) - 98
siergewassen - glastuinbouw - kasgewassen - rozen - chrysanten - alstroemeria - biologische bestrijding - organismen ingezet bij biologische bestrijding - geïntegreerde bestrijding - geïntegreerde plagenbestrijding - thrips - neoseiulus cucumeris - trialeurodes vaporariorum - aleyrodes - bemisia tabaci - amblyseius swirskii - euseius - iphiseius - roofmijten - orius - cryptolaemus montrouzieri - anagyrus pseudococci - planococcus citri - ornamental crops - greenhouse horticulture - greenhouse crops - roses - chrysanthemums - alstroemeria - biological control - biological control agents - integrated control - integrated pest management - thrips - neoseiulus cucumeris - trialeurodes vaporariorum - aleyrodes - bemisia tabaci - amblyseius swirskii - euseius - iphiseius - predatory mites - orius - cryptolaemus montrouzieri - anagyrus pseudococci - planococcus citri
The control of greenhouse pests in ornamental crops is getting more difficult because of the decreasing number of available pesticides. Alternative methods of pest control, based on biopesticides and natural enemies is promising, but not yet robust and reliable enough. In this project we developed and evaluated several methods to enhance the biological control of western flower thrips, Echinothrips americanus, whiteflies and mealybugs. Most studies were focused on preventive control measures that promote the establishment and efficacy of natural enemies by using top layers, alternative food, artificial domatia and a banker plant system. Furthermore we studied the interaction between parasitoids and predatory beetles for curative control of mealybugs. Finally, a number of (bio)pesticides was evaluated for their potential use as a correction tool against western flower thrips.
CO2 uit buitenlucht
Weel, P.A. van; Vanthoor, B.H.E. - \ 2016
Wageningen UR Glastuinbouw (Rapport GTB 1423) - 32
glastuinbouw - kooldioxide - ventilatie - freesia - tomaten - greenhouse horticulture - carbon dioxide - ventilation - freesia - tomatoes
The supply of additional CO2 in a greenhouse will be restricted in the future. The concentration in outside air has risen above 400 ppm. This may open the possibility to blow this air through the canopy to increase growth. In this project, the vertical CO2 concentration was measured in a vertical plane within to the canopy under different combinations of window opening, the activation of vertical fans and with or without dosing of additional CO2. For a Freesia and a tomato crop the result was that without CO2 dosing it was possible to maintain a concentration of over 350 ppm in the canopy at 5-10 cm distance from the leaf surface when the ventilation windows were open. Since, this is below outside concentration, additional supply of outside air may be an advantage. When extra CO2 was supplied, a reduction in window opening and the use of a screen increased the concentration between the canopy. The vertical distribution of CO2 within the canopy was never a problem. It can be concluded that the crop resistance to take up CO2 for a tomato and freesia crop is small and with respect to the other CO2 resistances, the crop resistance can be neglected. A positive effect of the use of vertical fans or the use of high pressure misting in the tomato greenhouse was not found, due to the strategy to keep the ventilation windows wide open. The concentration at 5-10 cm distance from the leaf is not necessarily the same concentration around the stomata because of boundary layer resistance. The effect of the boundary layer resitance on CO2 uptake is described in the report of Plant Dynamics called “Effecten van grenslaagweerstand op de fotosynthese bij tomaat en Freesia”.
Vochtbeheersing in kassen en terugwinning van latente energie : Een verkenning naar vochtbeheersing in kassen en de mogelijkheden van het terugwinnen van de energie die opgesloten zit in de gewasverdamping
Weel, P.A. van; Zwart, H.F. de; Voogt, J.O. - \ 2016
Wageningen UR Gastuinbouw (Rapport GTB 1421) - 76
kassen - kastechniek - tomaten - glastuinbouw - ontvochtiging - energiegebruik - energiebesparing - ventilatie - greenhouses - greenhouse technology - tomatoes - greenhouse horticulture - dehumidification - energy consumption - energy saving - ventilation
Dehumidification of a greenhouse by ventilation increases the energy input with 8-10 m3/m2.year of natural gas to compensate the heat losses. This study shows different methods to reduce those energy losses. A 25% reduction in ventilation is obtained by using heat exchangers connected to plastic distribution ducts or by using the Ventilationjet system. The sensible heat from the exhaust air can be used to heat the incoming outside air to greenhouse temperature. Heat exchangers with 100% efficiency to do that are available. The latent heat included in the water vapour leaving the greenhouse can be recovered by means of a condensating wall. A good working priciple is the Dewpoint Heat Exchanger in which outside air is wettened to reach the lowest possible temperature and then used to cool down the greenhouse air far below the temperature where condensation begins. The recovered latent heat must be stored in a water tank to use it in the heating pipes. Another approach is to skip ventilation and use a set of a cold and warm heat exchanger connected to a heat pump or to use a salt water absorber. The absorber opens the possibility to use solar or wind energy to dehumidify the greenhouse and collect 100% of the sensible and latent heat.
Plant reageert op korte en lange termijn verschillend op lichtkleur : onderscheid effecten fotosynthese en fotomorfogenese
Ieperen, W. van; Heuvelink, E. ; Kierkels, T. - \ 2016
Onder Glas 13 (2016)10. - p. 15 - 17.
kunstlicht - fotosynthese - plantenontwikkeling - fotomorfogenese - proefopzet - fotosynthetische actieve straling - belichting - glastuinbouw - artificial light - photosynthesis - plant development - photomorphogenesis - experimental design - photosynthetically active radiation - illumination - greenhouse horticulture
De inzichten in het effect van lichtkleuren op fotosynthese, vorm en ontwikkeling groeien gestaag. Je zou dan graag willen dat het om simpele relaties gaat, bijvoorbeeld ‘blauw licht opent huidmondjes’. Zo ligt het echter vaak niet. Effecten op korte en lange termijn zijn vaak verschillend en het gaat altijd om de mix van kleuren.
Hygiëne en bewustwording kan beter bij bloembollen en vaste planten : protocol valt of staat met naleven gedragsregels
Staalduinen, Jan van; Dam, M.F.N. van - \ 2016
Onder Glas 13 (2016)10. - p. 48 - 49.
bedrijfshygiëne - bloembollen - glastuinbouw - agrarische bedrijfsvoering - tuinbouwbedrijven - industrial hygiene - ornamental bulbs - greenhouse horticulture - farm management - market gardens
Bedrijven in de deelsectoren bloembollen en vaste planten kunnen met betere hygiënemaatregelen problemen voorkomen, menen deskundigen van onderzoeksinstellingen en kwaliteitsdiensten. “Ook met simpele oplossingen is de verspreiding van ziekten al te beperken”, stelt Marco van Dalen van Naktuinbouw. “Tijdens een workshop van één dagdeel helpen we telers graag op de goede weg.”
Less at the top, more gain at the bottom : better light penetration leads to higher production
Heuvelink, E. ; Kierkels, T. - \ 2016
In Greenhouses : the international magazine for greenhouse growers 5 (2016)4. - ISSN 2215-0633 - p. 18 - 19.
greenhouse horticulture - greenhouses - light penetration - crop production - farm management - diffused glass - glastuinbouw - kassen - lichtpenetratie - gewasproductie - agrarische bedrijfsvoering - diffuus glas
If light penetrates the crop better, it results in higher production. This is because the leaves that are deeper in the crop are a long way from their light saturation point. Diffuse glass or coatings and the distribution of the crop are the most applicable ways to achieve better light penetration. Other methods are usually beyond the reach of the grower
Potassium, the major organiser in numerous plant processes : involved in almost everything the plant turns into plant
Heuvelink, E. ; Kierkels, T. - \ 2016
In Greenhouses : the international magazine for greenhouse growers 5 (2016)4. - ISSN 2215-0633 - p. 46 - 47.
greenhouse horticulture - crop production - crop quality - potassium - plant development - nutrient requirements - glastuinbouw - gewasproductie - gewaskwaliteit - kalium - plantenontwikkeling - voedingsstoffenbehoeften
No potassium no plant: A huge number of processes are dependent on this element. Luckily, hardly any problems occur because the plant is good at looking after itself in this respect.
Stikstof blijkt behalve essentieel voedingselement ook signaalstof : aansturing van processen, zoals een hormoon
Heuvelink, E. ; Kierkels, T. - \ 2016
Onder Glas 13 (2016)9. - p. 20 - 21.
glastuinbouw - voedingsstoffenbehoeften - stikstof - plantenontwikkeling - greenhouse horticulture - nutrient requirements - nitrogen - plant development
Er is geen voedingselement waarvan de plant zoveel nodig heeft als stikstof. Het gehalte kan wel 5% van de drogestof uitmaken. Behalve als essentieel onderdeel van veel plantonderdelen en inhoudsstoffen, wordt ook steeds meer duidelijk dat stikstof een signaalstof is, die processen aanstuurt, bijna zoals een hormoon.