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.

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Humic substances interfere with phosphate removal by lanthanum modified clay in controlling eutrophication
Lurling, M.F.L.L.W. ; Waaijenberg, G.W.A.M. ; Oosterhout, J.F.X. - \ 2014
Water Research 54 (2014). - ISSN 0043-1354 - p. 78 - 88.
waterbodems - fosfaten - eutrofiëring - bioremediëring - laboratoriumproeven - water bottoms - phosphates - eutrophication - bioremediation - laboratory tests - rare-earth-elements - phosphorus-binding clay - organic-matter removal - modified bentonite clay - natural-waters - cyanobacterial toxins - polyaluminum chloride - cation binding - ion-binding - fresh-water
The lanthanum (La) modified bentonite Phoslock® has been proposed as dephosphatisation technique aiming at removing Filterable Reactive Phosphorus (FRP) from the water and blocking the release of FRP from the sediment. In the modified clay La is expected the active ingredient. We conducted controlled laboratory experiments to measure the FRP removal by Phoslock® in the presence and absence of humic substances, as La complexation with humic substances might lower the effectiveness of La (Phoslock®) to bind FRP. The results of our study support the hypothesis that the presence of humic substances can interfere with the FRP removal by the La-modified bentonite. Both a short-term (1 d) and long-term (42 d) experiment were in agreement with predictions derived from chemical equilibrium modelling and showed lower FRP removal in presence of humic substances. This implies that in DOC-rich inland waters the applicability of exclusively Phoslock® as FRP binder should be met critically. In addition, we observed a strong increase of filterable La in presence of humic substances reaching in a week more than 270 µg La l-1 that would infer a violation of the Dutch La standard for surface water, which is 10.1 µg La l-1. Hence, humic substances are an important factor that should be given attention when considering chemical FRP inactivation as they might play a substantial role in lowering the efficacy of metal-based FRP-sorbents, which makes measurements of humic substances (DOC) as well as controlled experiments vital.
Eutrophic urban ponds suffer from cyanobacterial blooms: Dutch examples
Waaijenberg, G.W.A.M. ; Faassen, E.J. ; Lurling, M. - \ 2014
Environmental Science and Pollution Research 21 (2014)16. - ISSN 0944-1344 - p. 9983 - 9994.
shallow lakes - water bodies - toxic cyanobacteria - northern poland - phosphorus flux - microcystins - fresh - phytoplankton - netherlands - health
Ponds play an important role in urban areas. However, cyanobacterial blooms counteract the societal need for a good water quality and pose serious health risks for citizens and pets. To provide insight into the extent and possible causes of cyanobacterial problems in urban ponds, we conducted a survey on cyanobacterial blooms and studied three ponds in detail. Among 3,500 urban ponds in the urbanized Dutch province of North Brabant, 125 showed cyanobacterial blooms in the period 2009-2012. This covered 79 % of all locations registered for cyanobacterial blooms, despite the fact that urban ponds comprise only 11 % of the area of surface water in North Brabant. Dominant bloom-forming genera in urban ponds were Microcystis, Anabaena and Planktothrix. In the three ponds selected for further study, the microcystin concentration of the water peaked at 77 µg l-1 and in scums at 64,000 µg l-1, which is considered highly toxic. Microcystin-RR and microcystin-LR were the most prevalent variants in these waters and in scums. Cyanobacterial chlorophyll-a peaked in August with concentrations up to 962 µg l-1 outside of scums. The ponds were highly eutrophic with mean total phosphorus concentrations between 0.16 and 0.44 mg l-1, and the sediments were rich in potential releasable phosphorus. High fish stocks dominated by carp lead to bioturbation, which also favours blooms. As urban ponds in North Brabant, and likely in other regions, regularly suffer from cyanobacterial blooms and citizens may easily have contact with the water and may ingest cyanobacterial material during recreational activities, particularly swimming, control of health risk is of importance. Monitoring of cyanobacteria and cyanobacterial toxins in urban ponds is a first step to control health risks. Mitigation strategies should focus on external sources of eutrophication and consider the effect of sediment P release and bioturbation by fish.
Plastic nets in agriculture ; a general review of types and applications
Castellano, S. ; Scarascia Mugnozza, G. ; Russo, G. ; Briassoulis, D. ; Mistriotis, A. ; Hemming, S. ; Waaijenberg, D. - \ 2008
Applied Engineering in Agriculture 24 (2008)6. - ISSN 0883-8542 - p. 799 - 808.
colored shade nets - radiometric properties - mechanical-behavior - greenhouse - screens - windbreak - virus - films - transmission - resistance
At the moment, there are a large number of agricultural net types on the market characterized by different structural features such as type of material, type and dimensions of threads, texture, mesh size, porosity / solidity and weight; by radiometric properties like color, transmissivity/reflectivity/shading factor; by physical properties like air permeability and several mechanical characteristics such as tensile stress, strength, elongation at break, and durability. Protection from hail, wind, snow, or strong rainfall in fruit-farming and ornamentals, shading nets for greenhouses and nets moderately modifying the microenvironment for a crop are the most common applications. A systematic review of the current state-of-the-art of structural parameters, standard and regulations, most common agricultural net applications, and their supporting structures has been developed by means of a literature study, technical investigations, concerning characteristics and use of nets. As a result, the survey highlighted that in many cases different, not even similar, net types were adopted for the same application and the same cultivations by various growers. Results show that neither growers nor net producers have clear ideas about the relationship between the net typology optimization for a specific application and the construction parameters of the net. The choice often depends on empirical or economic criteria and not on scientific considerations. Moreover, it appears that scientifically justified technical requirements for nets used in specific agricultural applications have not been established yet.
Development of a greenhouse system for tropical lowland in Indonesia
Hemming, S. ; Waaijenberg, D. ; Campen, J.B. ; Bot, G.P.A. ; Impron, I. - \ 2006
Wageningen UR - A&F (former IMAG) developed together with Plant Research International (PRI) and the Dutch industries Rovero Systems B.V. and Plasthill B.V. and the Indonesian company PT East West Seed Indonesia a new greenhouse system for the production of high quality horticultural products in the tropics. In this study plastic-covered greenhouses are designed which are particularly adapted to the regional circumstances of tropical lowland in Indonesia. The greenhouse design has enough resistance against local wind loads, has high natural ventilation, but is at the same time mainly closed for insects by using insect nets. The airflow and the temperatures in the greenhouse are simulated by CFD software during design stage to optimize greenhouse size, shape and the ventilation openings. A new plastic film covering is developed. The new covering consists of a 200 µm polyethylene film with a lifetime of about 3 years in Indonesia. The film contains a UV-block pigment and has highly light diffusing properties. Additionally film prototypes are developed, which selectively reflect near infrared radiation (NIR) with the objective to reach a cooling effect inside the greenhouse. Six identical greenhouse prototypes are produced in The Netherlands and built in the isle of Java in Indonesia in spring 2003. In the greenhouses tomatoes are cultivated and observed. Additionally climate measurements are carried out to evaluate the new designed greenhouses.
Design, construction and maintenance of greenhouse structures
Waaijenberg, D. - \ 2006
Acta Horticulturae 710 (2006). - ISSN 0567-7572 - p. 31 - 42.
In this paper a review is given about the effects of different parts of the solar radiation and its importance for plant growth in greenhouses. Besides the most important visible part of the light (PAR), ultraviolet (UV), near infrared (NIR) and far infrared (FIR) are discussed. The strength of the greenhouse structure can be calculated following the new European Standard for Greenhouses EN 13031-1. The orientation and the roof inclination at the greenhouse have limited influence on the light transmittance. The most important material properties of greenhouse cladding materials are presented for glass, plastic sheets (PMMA and PC) and plastic films (PE, PVC and ETFE). These properties can be modified in the different materials, which leads to improvements of the materials with respect to light transmission, heat transfer, condensation behaviour, etc. Some recent results of research of greenhouse cladding materials and structures are described, like `floating greenhouses¿, `closed greenhouses¿, ETFE membrane, a greenhouse for tropical lowland, zigzag-shape double PC-sheet and microstructural coated glass.
Haalbaarheid optimale foliekassen voor energie-extensieve teelten : Deelrapport: Inventarisatie mogelijke foliekasconstructies
Waaijenberg, D. ; Hemming, S. - \ 2006
Wageningen : Plant Research International (Nota / Plant Research International 381) - 27
teelt onder bescherming - polyethyleenfilm - kassen - geraamten - thermische schermen - nederland - glastuinbouw - protected cultivation - polyethylene film - greenhouses - frames - thermal screens - netherlands - greenhouse horticulture
In een haalbaarheidsstudie wordt nagegaan of door het op groter schaal inzetten van foliekassen het Nederlandse marktaandeel in de extensieve teelten mogelijk behouden kan blijven. In dit deelrapport worden aspecten rond om de constructie van foliekassen geinventariseerd
Greenhouse development for protected cultivation in the tropics
Hemming, S. ; Waaijenberg, D. - \ 2005
Fruit & Veg tech 4 (2005)7. - ISSN 1569-2930 - p. 26 - 27.
Einsatz von Netzen (aktuelles EU-projekt)
Waaijenberg, D. - \ 2005
Folie versus glas
Hemming, S. ; Waaijenberg, D. - \ 2005
De Boomkwekerij 18 (2005)51/52. - ISSN 0923-2443 - p. 26 - 28.
kassen - tunnels - teelt onder bescherming - kunststofweefsel - kunststoftunnels - glas - folie - lichtdoorlating - ultraviolette straling - luchttemperatuur - materialen - boomkwekerijen - glastuinbouw - uv-lampen - greenhouses - protected cultivation - plastic fabric - plastic tunnels - glass - foil - light transmission - ultraviolet radiation - air temperature - materials - forest nurseries - greenhouse horticulture - uv lamps
Bij het bouwen van een nieuwe kas, staat de boomkweker voor de keuze: glas of folie? De keus kan hij baseren op talrijke beoordelingscriteria. Wageningen UR zet de balangrijkste op een rij.
The solar greenhouse : a highly insulated greenhouse design with an inflated roof system with PVDF or ETFE membranes
Waaijenberg, D. ; Hemming, S. ; Campen, J.B. - \ 2005
Acta Horticulturae 691 (2005). - ISSN 0567-7572 - p. 561 - 568.
In a co-operation project of Wageningen University (Wageningen UR), Agrotechnology & Food Innovations B.V. (A&F), Priva Hortimation B.V. and Hyplast N.V. (Belgium) a greenhouse for the future has been developed. The project has four lines, namely 1. lowering the energy demand, 2. using solar energy for heating (greenhouse as solar collector), 3. modifying climate control and dehumidification and 4. developing of the highly insulated greenhouse. This paper deals with the development of the so-called Solar Greenhouse, the structure and cladding material and the (natural) ventilation openings. The aspects that play an important role in the process of development of the greenhouse are the strength of the structure, the light transmittance, the material consumption and the expected greenhouse climate. The high demands for energy savings lead to a greenhouse covering with a high insulation value and at the same time a high light transmittance. Advanced materials like fluor polymer films in double or more layers with the space in between inflated have these qualities. The most perspective greenhouse geometry is a saw-tooth roof structure with roof inclinations of 200 and 300, a span width of 10m and a vertical opening of 2 m for natural ventilation. The module for the greenhouse is repeatable in both directions to a big area. Caused by the asymmetric geometry of the greenhouse (openings oriented on one side) the influence of the wind and wind direction is extensive
Light and insulating properties a variable factor
Hemming, S. ; Waaijenberg, D. - \ 2005
FlowerTECH 8 (2005)1. - ISSN 1388-8439 - p. 20 - 23.
kassen - licht - doorschijnendheid - kunststoffen - siergewassen - chrysanten - gewasproductie - opbrengst - kosten-batenanalyse - bouwmaterialen - greenhouses - light - translucence - plastics - ornamental crops - chrysanthemums - crop production - outturn - cost benefit analysis - building materials
Kennis van licht en warmte doorlatende eigenschappen van kasmaterialen biedt telers de mogelijkheid de beste keuze te maken voor hun productie. Een vergelijking tussen glastypen en plastics
Greenhouse development for protected cutivation in the tropics
Hemming-Hoffmann, S. ; Waaijenberg, D. - \ 2004
Niet alleen door glas valt licht in de kas
Waaijenberg, D. ; Marissen, N. ; Hemming-Hoffmann, S. - \ 2004
Groenten en Fruit. Algemeen 2004 (2004)37. - ISSN 0925-9694 - p. 28 - 29.
licht - kassen - natuurlijk licht - daglicht - lichtdoorlating - bouwmaterialen - kosten - light - greenhouses - natural light - daylight - light transmission - building materials - costs
Zoveel mogelijk licht in de kas wordt bereikt met verlichting en door zonlicht optimaal te gebruiken. Er speelt echter nòg een factor mee. Het materiaal waarmee een kas is opgebouwd, levert eveneens een belangrijke bijdrage aan de hoeveelheid en het soort licht dat die kas binnenkomt. Gegevens in bijgaande tabel: Lichtdoorlatendheid, levensduur en prijsindicatie kasomhullingsmaterialen
Kassen en tunnels : het ene kasdekmateriaal is het andere niet
Waaijenberg, D. ; Marissen, N. ; Hemming-Hoffmann, S. - \ 2004
De Boomkwekerij 17 (2004)38. - ISSN 0923-2443 - p. 10 - 11.
kassen - lichtdoorlating - natuurlijk licht - kunststoffen - glas - diffuus glas - gecoat glas - folie - greenhouses - light transmission - natural light - plastics - glass - diffused glass - coated glass - foil
Voor een optimale gewasgroei moet het kasdek zo veel mogelijk het juiste licht doorlaten. Het kasdek kan bestaan uit glas, kunststofplaten of folie. Wat zijn de verschillen? En welke ontwikkelingen zijn er per materiaal te bespeuren? Gegevens in bijgaande tabel: Belangrijke eigenschappen van glas, hunststofplaten en folies ten aanzien van PAR direct, PAR diffuus, K-waarde (warmteweerstand van het materiaal), levensduur en prijsindicatie
Alles om te weten bij de keuze van het kasdekmateriaal
Waaijenberg, D. ; Marissen, N. ; Hemming-Hoffmann, S. - \ 2004
Vakblad voor de Bloemisterij 59 (2004)35. - ISSN 0042-2223 - p. 36 - 37.
sierplanten - kassen - bekleding, bouw - kunststofbekleding - constructie - natuurlijk licht - energiebehoud - glastuinbouw - ornamental plants - greenhouses - cladding - plastic cladding - construction - natural light - energy conservation - greenhouse horticulture
Agrotechnology & Food Innovations (het voormalige IMAG), Plant Research International en PPO hebben in opdracht van LNV en Productschap Tuinbouw in het kader van het energieonderzoek een uitgebreide studie gemaakt over 'Optimaal gebruik van natuurlijk licht in de glastuinbouw'. In een reeks van vier artikelen, waarvan dit het tweede is, doet het Vakblad daar verslag van. Gegevens in bijgaande tabellen over materiaaleigenschappen van glas, kunststofplaten en folies en foliemateriaal
Optimaal gebruik van natuurlijk licht in de glastuinbouw
Hemming, S. ; Waaijenberg, D. ; Bot, G. ; Sonneveld, P. ; Zwart, F. de; Dueck, T.A. ; Dijk, C.J. van; Dieleman, J.A. ; Marissen, N. ; Rijssel, E. van; Houter, G. - \ 2004
Wageningen : Agrotechnology & Food Innovations (Rapport / Agrotechnology & Food Innovations nr. 100) - ISBN 9067547670 - 155
licht - natuurlijk licht - fotoperiode - fotoperiodiciteit - fotosynthese - kasgewassen - isolatiematerialen - energiebehoud - kassen - glastuinbouw - light - natural light - photoperiod - photoperiodism - photosynthesis - greenhouse crops - insulating materials - energy conservation - greenhouses - greenhouse horticulture
Natuurlijk licht is een van de belangrijkste factoren met betrekking tot de groei en ontwikkeling van planten. Door het proces van fotosynthese maakt de plant bouwstoffen aan voor de groei vanuit de onderdelen licht, water en CO2. In dit rapport wordt enerzijds de lichtbehoefte van gewassen besproken en anderzijds de technische mogelijkheden van omhullingsmaterialen en schermen om het licht in de kas te beïnvloeden. Het rapport beperkt zich tot het natuurlijke licht en laat dus het kunstlicht hier buiten beschouwing. Na een inleiding in hoofdstuk 1 volgt in hoofdstuk 2 de beschrijving wat licht en globale straling is, wat de hoeveelheid straling is in verschillende seizoenen, uit welke lichtkleuren de globale straling is samengesteld en hoe de daglengte in Nederland varieert. In hoofdstuk 3 is beschreven wat de lichtbehoefte van planten voor de fotosynthese en de morfogenese is. Tevens is de lichtbehoefte van gewassen tijdens de opkweek van het uitgangsmateriaal en tijdens de productiefase onderzocht. Per gewasgroep (vruchtgroenten, bladgroenten, snijbloemen, potplanten) wordt aangegeven welke lichtintensiteit en welk spectrum nodig is, om een optimale gewasproductie te realiseren. In hoofdstuk 4 wordt geïnventariseerd, welke kasomhullings- en schermmaterialen er zijn, welke optische eigenschappen relevant zijn om natuurlijk licht in de kas door te laten dringen en welke technische mogelijkheden er zijn om deze materiaaleigenschappen aan te passen. In dit hoofdstuk wordt gekeken hoe een bepaalde lichtbehoefte voor een gewasgroep gerealiseerd of geoptimaliseerd zou kunnen worden en wat daarvan de gevolgen voor het gewas zijn. Aangezien natuurlijk licht tevens invloed heeft op de warmtebalans in een kas wordt ook het effect van de verschillende lichtbestanddelen op de energiehuishouding van de kas besproken. De kernresultaten zijn in hoofdstuk 5, de synthese samengevat, onderverdeeld naar de behoeften van gewasgroepen.
The application of F-clean membrane as greenhouse covering material
Hemming, S. ; Waaijenberg, D. - \ 2003
Wageningen : IMAG (IMAGnota V2003-03) - 33 p.
Greenhouse design for the future with a cladding material combining high insulation capacity with high light transmittance
Waaijenberg, D. ; Sonneveld, P.J. - \ 2003
Acta Horticulturae (2003)633. - ISSN 0567-7572 - p. 137 - 143.
For the world exhibition Floriade 2002 in The Netherlands a greenhouse design is developed by IMAG together with General Electric Plastics, Bergen op Zoom with polycarbonate double-web sheets with a zigzag-shaped surface. Intensive research was completed to develop the special zigzag shape of the plastic sheets resulting in an enhanced light transmittance and energy saving of approximately 20% over the whole year. The optimal dimensions for the sheets with respect to light transmittance, strength and insulation is a pattern of 50 mm for the zigzag shape, a thickness of 25 mm and the inclination of the pattern is 50°. The transmittance for diffuse light of the entire greenhouse with the double-web sheets is 78.8%.
Measurement of optical properties of greenhouse cladding materials : harmonisation and standardisation
Waaijenberg, D. ; Gbiorczyk, K. ; Feuillloley, P. ; Verlodt, I. ; Bonora, M. - \ 2003
Acta Horticulturae (2003)633. - ISSN 0567-7572 - p. 107 - 113.
The aim of this European SMT (Standards, Measurements and Testing) project was the development of testing methods for measuring the ageing and the condensation behaviour of plastic films. For the ageing task, the degradation rates of the most important physical, optical and mechanical properties of the film were measured. Amongst others, harmonisation had to be achieved on measuring the optical properties of plastic films. For this purpose identical samples of four different co-polymer films and also special antifog films were measured by the partners. Measured were the direct and diffusive light transmittance, haze, the UV- transmittance and the IR-transmittance (longwave). Harmonisation has been achieved on the terminology, methods, set-up, repetitions, wavelength bands, etc. of the optical properties of greenhouse plastic films.
Mission report 2, PROCULT Protected Cultivation in Tropical Lowland
Bot, G.P.A. ; Waaijenberg, D. - \ 2003
onbekend : Agrotechnology & Food Sciences Group - 20 p.
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