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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Kennisdossier winterbescherming
Dalfsen, P. van - \ 2012
Boskoop : Greenport Regio Boskoop Kennis & Innovatie Impuls
boomkwekerijen - vorst - winter - vorstwering - cultuurmethoden - klimaatverandering - kennisoverdracht - risicofactoren - forest nurseries - frost - frost protection - cultural methods - climatic change - knowledge transfer - risk factors
Het risico op vorstschade in de boomkwekerij kan zich uiten in complete uitval van de plant of kwaliteitsverlies (bijv. dode scheuten). Dit kennisdossier zet op een rij hoe vorstschade ontstaat en wat je er tegen kunt doen.
'Vrijloopstallen in de vorst' februari 2012
Animal Sciences Group (ASG), - \ 2012
[S.l.] : Verantwoorde veehouderij
loopstallen - rundveehouderij - stalinrichting - compost - dierenwelzijn - vloerbedekking - vorst - dierlijke productie - huisvesting, dieren - melkvee - loose housing - cattle husbandry - animal housing design - composts - animal welfare - floor coverings - frost - animal production - animal housing - dairy cattle
Gesproken werd met enkele veehouders in februari 2012, toen het al anderhalve week onafgebroken (streng) had gevroren. Meindert Wiersma werkt met een composteringsbodem (warmteontwikkeling) met houtsnippers en zowel Marc Havermans als Jeroen Groenewegen werken met compost. In dit document staan hun ervaringen en hun verschil in aanpak.
Modeling and Forecasting the Onset and Duration of Severe Radiation Fog under Frost Conditions
Velde, I.R. van der; Steeneveld, G.J. ; Wichers Schreur, B.G.J. ; Holtslag, A.A.M. - \ 2010
Monthly Weather Review 138 (2010). - ISSN 0027-0644 - p. 4237 - 4253.
meteorologie - weersvoorspelling - vorst - mist - modellen - meteorology - weather forecasting - frost - fog - models - nocturnal boundary-layer - land-surface - parameterization schemes - bulk parameterization - numerical prediction - contrasting nights - mesoscale - clouds - simulation - resolution
A case of a severe radiation fog during frost conditions is analyzed as a benchmark for the development of a very high resolution NWP model. Results by the Weather Research and Forecasting model (WRF) and the High resolution limited area model (HIRLAM) are evaluated against detailed observations to determine the state of the art in fog forecasting and to derive requirements for further research and development. For this particular difficult case, WRF is unable to correctly simulate the fog for none of the parameterizations and model configurations utilized. Contrary, HIRLAM does model the onset of fog, but is unable to represent it beyond the lowest model layer, which leads to an early dispersal of fog in the morning transition. The sensitivity of fog forecasts to model formulation is further analyzed with a high resolution single column version of HIRLAM, and with the Duynkerke (1991) single column model as a reference. The single column results are found to be sensitive to the proper specification of the external forcings. It is reconfirmed that high vertical resolution is essential for modeling the fog formation, the growth of the fog layer and when the fog lifts for the maintenance of a stratus deck. The properly configured column models are able to accurately model the onset of fog and its maturation, but fail in the simulation of fog persistence and subsequent dispersal. Details of the turbulence parameterization appear to be important in this process. It is concluded that, despite of all advances in numerical weather prediction, fog forecasting is still a major challenge
Mogelijkheden van een brede weersverzekering
Meulen, H.A.B. van der; Asseldonk, Marcel van; Buurma, J.S. ; Nienhuis, J.K. - \ 2006
Den Haag : LEI (Rapport / LEI : Domein 6, Beleid ) - ISBN 9086151019 - 47
verzekering - weer - landbouwsector - risico - hagel - sneeuw - vorst - droogte - stormen - landbouwverzekering - verzekering tegen hagel - nederland - insurance - weather - agricultural sector - risk - hail - snow - frost - drought - storms - agricultural insurance - hail insurance - netherlands
Dit onderzoek, een coproductie van het LEI en IRMA, beschrijft de mogelijkheden van een brede weersverzekering in de agrarische sector. In een brede weersverzekering dienen zoveel mogelijk weerrisico's te worden meegenomen, zoals storm, hagel, regen, sneeuw, vorst en droogte. Er is enerzijds aandacht voor de theoretische aspecten die het mogelijk maken om al dan niet tot een brede weersverzekering te komen. Anderzijds is er een stakeholderanalyse uitgevoerd onder sectorvertegenwoordigers en verzekeraars. Hierbij draait het om de vraag welke visies, belangen, wensen en ambities een rol spelen bij de opzet van een brede weersverzekering in de praktijk. This study, carried out jointly by LEI and IRMA, describes the options for broad weather insurance within the agricultural sector. As many weather-related risks as possible must be considered within broad weather insurance, such as gales, hail, rain, snow, frost and drought. On the one hand, attention is devoted to the theoretical aspects that may or may not make it possible to put together a broad weather insurance scheme. On the other hand, a stakeholder analysis has been carried out among sector representatives and insurance companies. The core issues here are which visions, interests, wishes and ambitions play a role in setting up a broad weather insurance scheme in practice.
Vermindering nachtvorstschade in zetmeelaardappelen
Wijnholds, K.H. - \ 2005
Kennisakker.nl 2005 (2005)15 okt.
aardappelen - solanum tuberosum - beschadigingen door vorst - vorst - gewasbescherming - bevochtigen - vorstwering - zout - fabrieksaardappelen - akkerbouw - potatoes - frost injury - frost - plant protection - wetting - frost protection - salt - starch potatoes - arable farming
In het voorjaar kan op venige perceelsgedeelten veel schade aan aardappelen (en bieten) ontstaan door nachtvorst. Vanuit de fruitteelt is bekend dat beregening tijdens nachtvorst bevriezing kan voorkomen. Voortbouwend op dit idee is in 2003 een pottenproef in een vriescel uitgevoerd door het HLB. Geprobeerd is om met een gewasbespuiting met een zoutoplossing de vorstgevoeligheid te verminderen. Uit dit onderzoek bleek echter dat, bij alleen bevochtigen kort voor de nachtvorst, de aardappelplant juist gevoeliger werd voor het optreden van vorstschade. Het toevoegen van zout resulteerde in een vermindering van de schade. De schade was echter nog steeds groter dan bij een droog gewas. De nachtvorst is in het onderzoek nagebootst in een vriescel. In een vriescel worden de aardappelplanten niet nat door dauw. De verwachting is dat onder natuurlijke omstandigheden het gewas wel nat wordt door dauw kort voor het optreden van nachtvorst. Via een bureaustudie met gegevens van het weer voor en tijdens nachtvorst is nagegaan of voor het optreden van nachtvorst de bladeren vochtig zijn.
Environmental stress in German forests; assessment of critical deposition levels and their exceedances and meteorological stress for crown condition monitoring sites in Germany
Klap, J.M. ; Reinds, G.J. ; Bleeker, A. ; Vries, W. de - \ 2000
Wageningen : Alterra (Alterra-rapport 134) - 73
bossen - bosschade - monitoring - kou - verzuring - vorst - stikstof - zure depositie - stressfactoren - droogte - modellen - luchtverontreiniging - duitsland - forests - forest damage - cold - acidification - frost - nitrogen - acid deposition - stress factors - drought - models - air pollution - germany
Site-specific estimations of meteorological stress and atmospheric deposition were made for the systematic 8 x 8 km2 forest condition monitoring network in Germany for the years 1987-1995. Winter cold and late frost were important temperature stress variables and relative transpiration was a good indicator of drought stress. All variables showed considerable temporal and spatial variation. Present loads of nitrogen and acidity were modelled with an adapted version of the EDACS model and combined withcritical loads and critical deposition levels based on the SMB model. Both present loads and the extents of exceeding showed considerable spatial variation and a clear decrease in time.
Invloed vernalisatie op groei en ontwikkeling bij Gypsophila paniculata 'Perfecta'
Nijssen, H.M.C. ; Mourik, N.M. van - \ 1997
Aalsmeer : Proefstation voor Bloemisterij en Glasgroente (Rapport / Proefstation voor Bloemisterij en Glasgroente 123) - 18
sierplanten - kou - vorst - groei - plantenontwikkeling - rapporten - gypsophila paniculata - ornamental plants - cold - frost - growth - plant development - reports
Effect van vorst op de kwaliteit van zand - bentoniet - afdichtingen
Weitz, A.M. ; Boels, D. - \ 1993
Wageningen : DLO-Staring Centrum (Rapport / DLO-Staring Centrum 301) - 36
vorst - stortterreinen - huisvuilverwijdering - vuilnisbelten - verzegelen - bodembescherming - afvalverwijdering - afvalstortplaatsen - bekledingen - frost - landfills - municipal refuse disposal - refuse tips - sealing - soil conservation - waste disposal - waste disposal sites - linings
Heat and mass transfer in frozen porous media
Loon, W. van - \ 1991
Agricultural University. Promotor(en): J. Schenk; I.A. van Haneghem. - S.l. : Van Loon - 204
vibratie - geluidsleer - reflectie - resonantie - thermodynamica - warmte - warmteoverdracht - thermische geleiding - transmissie - hydrodynamica - vloeistoffen (liquids) - vloeistoffen (fluids) - stroming - poreus medium - vorst - bodem - dampdruk - tensiometers - effecten - temperatuur - kou - meting - elektrische eigenschappen - vibration - acoustics - reflection - resonance - thermodynamics - heat - heat transfer - thermal conductivity - transmission - hydrodynamics - liquids - fluids - flow - porous media - frost - soil - vapour pressure - effects - temperature - cold - measurement - electrical properties
<p><TT>In this thesis processes and parameters associated with heat and mass transfer in frozen porous media both on a theoretical and empirical basis are studied. To obtain the required measurements some existing measuring methods needed to be improved.</TT><p><TT>Firstly, an improved model has been developed for the measurement of thermal conductivity with use of the nonsteady-state probe method. The measurements of thermal conductivity indicate four separate effects caused by the freezing process.</TT><p><TT>The second improved measuring method is the measurement of bulk electrical conductivity with use of time-domain reflectometry.</TT><p><TT>And the third improvement is the use of the dispersion theory in the description of relations between water content and bulk electrical conductivity or dielectric constant.</TT><p><TT>This thesis shows that time-domain reflectometry can be used to measure the unfrozen water content and bulk electrical conductivity simultaneously under frozen conditions and that from the latter parameter solute redistribution can be monitored.</TT><p><TT>From the measured heat flows a time delay in the forming of pore ice can be concluded. From the measured moisture transport (resulting in frost heave) a relation with some soil properties could be established. For some of the materials studied a minimum temperature gradient has been observed at</TT>which<TT>heave starts. From this and other results an effort was made to come to a synthesis of the rigid ice concept and the segregation potential concept.</TT><p><TT>The thesis finishes with some recommandations in connection with the improvement of soil structure by freezing, frost heave and artificial ground freezing.</TT>
The effects of low temperature on seedling growth of maize genotypes
Miedema, P. ; Post, J. ; Groot, P.J. - \ 1987
Wageningen : Pudoc (Agricultural research reports no. 926) - 124
groeistadia - gewassen, groeifasen - zea mays - maïs - kou - vorst - growth stages - crop growth stage - maize - cold - frost
Onderzoek naar vorstverschijnselen in grond
Ketelaars, P.H.J.M. - \ 1987
Agricultural University. Promotor(en): L. Wartena; I.A. van Haneghem. - S.l. : Ketelaars - 135
engineering - vorst - beschadigingen door vorst - permafrost - onderzoek - bodem - frost - frost injury - research - soil
After the winter of 1962-1963 the frost damage in the Netherlands to road constructions was enormous. The "Studie Centrum Wegenbouw" made inquiries on road constructors about this damage. A special commision was brought together to look after these inquiries. It proved that many physical aspects about frost penetration were unknown. One of the activities therefore had to be a study on frost penetration into soils. For this reason a new freezing model is derived. With this model values for frost depths and heave can be calculated with it. The new model differs from known models because of different assumptions. Two important conditions are the original temperature distribution and the original water distribution. Both are assumed to be linear functions of place. The interpretation of masstransport and frozen fringe differs from Jones and Miller. The transport is in agreement with Darcy's law. However, the quantity of transported mass is not only depending on the waterpotentialgradient itself, but also on the location of this gradient and on time. The importance of the factor time follows from the heatfluxes at the freezingfront.

Model values are compared with experimental results. Three different types of setups are used. A closed system (no free water) was used to investigate the influence of watercontent on frost penetration. Moisted silversand was applied. The volumemetric watercontent, changed to 6%. By the so called T.R.R.L. method an opensystem (free water available) was copied. Moistured morainesand was used. Measured frostdepths and heaves are compared with calculated values. A frost-tube, developed by the "Heidemaatschappij" was used to measure frostdepths in the field.Several tubes were placed at different locations into the soil. Airtemperatures and frostdepths were measured during winterperiods. The measurements of the winter 1979 are used here. Unfortunately there was no knowledge about several thermal parameters. The missing values were replaced by the numbers of morainesand.

A simple numerical program is developed and used to find the calculated values for frostdepths and heaves.

Influence of external factors on growth and development of sugar-beet (Beta vulgaris L.)
Smit, A.L. - \ 1983
Landbouwhogeschool Wageningen. Promotor(en): L.J.P. Kupers, co-promotor(en): G.J. Vervelde. - Wageningen : Pudoc - 109
beta vulgaris - kou - vorst - zaden - stratificatie (zaden) - suikerbieten - cold - frost - seeds - stratification - sugarbeet
Several trials on the quantitative influence of photophase, chilling (vernalization) and high temperature (devernalization) on bolting of sugar-beet were analysed on the basis of a simple physiological model, in which bolting is considered as the final event of dynamic, momentary and quantitative processes in the plant. Trials in the field and in growth chambers examined factors in chilling and in light response. The inhibitory effect on bolting of high temperatures and the role of photophase in this process was investigated for several periods after vernalization.<p/>Growth and bolting seem to be correlated, as plants with just visible bolting were usually heavier.<p/>A possible relation between bolting resistance and vigour was investigated. Also the influence of photophase and cold treatment on growth was measured in a trial.<p/>Some ways are shown of using a climatic factor like temperature to predict bolting in the field. Finally some recommendations for sugar-beet breeders are drawn up.
Pedogenic and sedimentary characteristics of a date Glacial Holocene solifluction deposit at Hjerupsgyde, Funen, Denmark
Schwan, J. ; Miedema, R. ; Cleveringa, P. - \ 1982
Catena 9 (1982). - ISSN 0341-8162 - p. 109 - 138.
denemarken - vorst - permafrost - bodemvorming - glaciale perioden - denmark - frost - soil formation - glacial periods
Effects of vernalization and daylength in cultivated dicotyledones : literature 1970 - 1974
Anonymous, - \ 1974
Wageningen : [s.n.] (Literatuurlijst / Centrum voor landbouwpublikaties en landbouwdocumentatie no. 3636)
bibliografieën - kou - cultuurmethoden - bloei - vorst - plantenfysiologie - bibliographies - cold - cultural methods - flowering - frost - plant physiology
Nachtvorst en microklimaat : in het bijzonder in jonge bosaanplant
Schneider, T. - \ 1967
University. Promotor(en): W.R. van Wijk; D.A. de Vries. - Wageningen : Veenman - 82
vorst - microklimaat - bodem - landschap - weer - modificatie - oogstschade - beschadigingen door vorst - plantenfysiologie - bosschade - beschadigingen door koude - kou - frost - microclimate - soil - landscape - weather - modification - crop damage - frost injury - plant physiology - forest damage - cold injury - cold
In forestry frost may cause considerable damage. A purpose of this publication was to consider whether any of the many methods of preventing frost were suitable for forestry. Much of the research was devoted to a description of the microclimate and the relation between the physical phenomena occurring in the lowest air layers during inversion conditions.

The different terms of energy balance were estimated or calculated with special attention to net long-wave radiation, the soil heat flux and the heat flux in the air. After an introduction on turbulence and convection, the turbulent transfer in neutral and thermally stratified conditions was discussed. The thermal stability indices and the transport coefficients for heat and momentum proved to be important parameters. Measured and calculated windspeeds and air temperatures were compared for different weather conditions.

After a short review of recent literature on frost damage and frost resistance in plants, different methods of preventing frost were presented and explained. An application of passive methods was demonstrated by the measurements at different sites in the Netherlands and Tunisia.

Vernalization in Cheiranthus allionii Hort.
Barendse, G.W.M. - \ 1964
University. Promotor(en): S.J. Wellensiek. - Wageningen : Veenman - 64
brassicaceae - sierplanten - cultuur zonder grond - plantenfysiologie - kou - vorst - ornamental plants - soilless culture - plant physiology - cold - frost
The effect of vernalization in Cheiranthus allionii, a qualitative winter annual requiring cold, was studied in relation to external conditions, particularly temperature and day length. Both seed and plant vernalization may lead to flower formation. However, the vernalizability varied with the plant's age. There was a close relation between age, duration of vernalization and daylength after vernalization. In long days after vernalization seeds and older plants were most sensitive to vernalization, young plants being less sensitive. Short days after vernalization of either seeds or young plants diminished the effectiveness of vernalization but this disadvantageous effect was partly overcome by vernalizing for longer. Mature plants were day neutral after vernalization. Warmth (35°C) immediately after vernalization caused devernalization. However, warmth immediately before vernalization antagonized vernalization.

Only vernalized growing points and those derived from vernalized tissue attained a vernalized state.

The mechanism of vernalization was discussed in the light of the results with Cheiranthus allionii and the different published theories. It was concluded that the immediate product of vernalization was immobile.

Cold requirements of witloof Chicory varieties (Chichorium intybus L.) as a yield-determining factor
Huyskes, J.A. - \ 1962
Wageningen : I.V.T. (Mededeling / Instituut voor de Veredeling van Tuinbouwgewassen 180)
cichorei - cichorium intybus - kou - cultivars - vorst - rassen (taxonomisch) - rassen (planten) - chicory - cold - frost - races - varieties
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