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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    Development of a lactic acid production process using lignocellulosic biomass as feedstock
    Pol, E.C. van der - \ 2016
    Wageningen University. Promotor(en): Gerrit Eggink, co-promotor(en): Ruud Weusthuis. - Wageningen : s.n. - ISBN 9789462576735 - 167
    lignocellulose - biomass - biobased chemicals - sugarcane bagasse - lactic acid - sugars - byproducts - inhibitors - pretreatment - bacillus coagulans - furfural - saccharification - fermentation - quantitative techniques - production processes - lignocellulose - biomassa - chemicaliën uit biologische grondstoffen - suikerrietbagasse - melkzuur - suikers - bijproducten - remmers - voorbehandeling - bacillus coagulans - furfural - versuikering - fermentatie - kwantitatieve technieken - productieprocessen

    The availability of crude oil is finite. Therefore, an alternative feedstock has to be found for the production of fuels and plastics. Lignocellulose is such an alternative feedstock. It is present in large quantities in agricultural waste material such as sugarcane bagasse.

    In this PhD thesis, lignocellulose is chemically and enzymatically pretreated to depolymerise sugars present in this structure. The released sugar monomers are fermented by micro-organisms to lactic acid, which is a precursor for the bioplastic PLA. In this thesis, it is shown that it is possible to produce lactic acid from lignocellulosic biomass with high yields and high productivities.

    Monitoring gesloten teelt - komkommer
    Bonants, P.J.M. ; Hofland-Zijlstra, J.D. ; Weerdt, M. de; Hoof, R.A. van; Schoen, C.D. - \ 2009
    teelt onder bescherming - gesloten systemen - komkommers - cucumis sativus - pathogenen - monitoring - kwantitatieve technieken - detectie - bestrijdingsmethoden - glastuinbouw - protected cultivation - closed systems - cucumbers - cucumis sativus - pathogens - monitoring - quantitative techniques - detection - control methods - greenhouse horticulture
    Nieuwe moleculaire detectietechnieken kunnen snel en specifiek ziekteverwekkers in het teeltsysteem aantonen. Op basis van deze moleculaire technieken bieden een aantal bedrijven onderzoekspakketten aan voor gebruik in de Nederlandse glastuinbouw om meerdere ziekteverwekkers in een monster te monitoren. Waar en wanneer moet bemonsterd worden in het systeem? Posterpresentatie
    OSPAR-OIC Intercalibration Study on metals in produced water samples: a QUASIMEME Laboratory performance Study
    Velzeboer, I. ; Crum, S.J.H. ; Karman, C.C. - \ 2009
    IJmuiden : IMARES (Final report / Wageningen IMARES C014/09) - 23
    mariene constructies - offshore - marien milieu - zware metalen - kalibratie - kwantitatieve technieken - instrumenten (meters) - monitoring - bemonsteren - kwaliteitsnormen - verontreinigd water - marine structures - offshore - marine environment - heavy metals - calibration - quantitative techniques - instruments - monitoring - sampling - quality standards - polluted water
    The Offshore Industry Committee (OIC) of OSPAR discussed in its 2008 meeting the reporting of inputs of metals from offshore installations. INPUT is currently compiling data and information on discharges and emissions to the OSPAR maritime area to be used in the Quality Status Report (QSR). This includes an assessment of the inputs of cadmium, lead, and mercury in produced water. Initial estimates were considered by OIC to be unrepresentative, since many of the analyses recorded values below the analytical detection limits of the techniques used. Given the urgency of producing reliable information that could be used to prepare estimates of inputs of cadmium, lead, and mercury for the QSR, OIC agreed to conduct a further study, using the assistance of Quasimeme, to ensure quality assurance from sampling to measurement and reporting. This report focuses on the intercalibration exercise.
    'Nnumerieke verdroging'
    Gaast, J.W.J. van der; Massop, H.T.L. ; Vroon, H.R.J. - \ 2008
    H2O : tijdschrift voor watervoorziening en afvalwaterbehandeling 41 (2008)11. - ISSN 0166-8439 - p. 14 - 16.
    waterbeheer - grondwaterstand - kwantitatieve technieken - meting - verdroging - watertekort - grondwater - water management - groundwater level - quantitative techniques - measurement - desiccation - water deficit - groundwater
    In H2O nummer 5 van 2008 stond een Platform-artikel van de hand van de heren Van der Gaast, Vroon en Massop over 'numerieke verdroging'. Hierop is in dit nummer een tweetal reacties geplaatst. Dit eerste artikel is een reactie op een reeks van artikelen van Van der Gaast et al over numerieke verdroging. Ondergetekenden zijn het eens met hun oordeel ‘Meten is weten, mits we weten wat we meten’ en achten hun onderzoek waardevol, aangezien het inzicht verschaft in het vaststellen van het freatisch grondwaterniveau en de methodische problemen die daarbij komen kijken. Wel hebben we moeite met welke boodschap de onderzoeksresultaten naar buiten zijn gebracht en hoe daarbij het begrip verdroging is gebruikt. De lezer zou op basis van deze artikelen de indruk kunnen krijgen dat de verdrogingsproblematiek zodanig is overschat en dat we er in termen van hydrologisch herstel, voor wat betreft de grondwaterstand, al bijna zijn. Inclusief weerwoord van Van der Gaast, Massop en Vroon
    Opsporing verzocht...
    Bonants, P.J.M. ; Doorn, R. van; Hoof, R.A. van; Mendes, O. ; Schoen, C.D. - \ 2008
    gewasbescherming - kwantitatieve technieken - dna - testen - moleculaire diagnostiek - plant protection - quantitative techniques - dna - testing - molecular diagnostics
    Plant Research International ontwikkelt multiplex kwantitatieve testen. Deze testen kunnen meerdere gewasbelagers tegelijkertijd aantonen, maar ook precies vertellen hoeveel er van die gewasbelager aanwezig is. Zo kan er gericht en adequaat worden ingegrepen. Ook wordt er in de nieuw ontwikkelde testen veel gebruik gemaakt van moleculaire DNA-technieken
    Monitoring gesloten teelt - komkommer
    Bonants, P.J.M. ; Hofland-Zijlstra, J.D. ; Weerdt, M. de; Hoof, R.A. van; Schoen, C.D. - \ 2007
    gewasbescherming - gesloten systemen - komkommers - pathogenen - bestrijdingsmethoden - monitoring - kwantitatieve technieken - detectie - monsters - glasgroenten - plant protection - closed systems - cucumbers - pathogens - control methods - monitoring - quantitative techniques - detection - samples - greenhouse vegetables
    In de teelt van komkommer kunnen talloze plantenpathogenen voorkomen. Momenteel worden door diverse laboratoria testen aangeboden voor individuele pathogenen (kwantitatief) of meerdere (kwalitatief). Detectie van meerdere pathogenen of antagonisten kwantitatief zou een toegevoegde waarde vormen. Onderzoek wordt daarom verricht met o.a. als doel de ontwikkeling van probes voor kwantitatieve multiplex detectie op praktijkmonsters
    Aanzet tot een betrouwbare populatiedichtheid bepaling van wratziekte (Synchytrium endobioticum)
    Been, T.H. ; Lamers, J.G. - \ 2007
    Wageningen : Plant Research International (Rapport / Plant Research International 162) - 8
    populatiedichtheid - synchytrium endobioticum - kwantitatieve technieken - micro-organismen - analytische methoden - bodempathogenen - population density - synchytrium endobioticum - quantitative techniques - microorganisms - analytical methods - soilborne pathogens
    Bij de bepaling van de populatiedichtheid van een bodemgebonden organisme hangt de betrouwbaarheid van de uiteindelijk aangebonden aantallen af van twee belangrijke foutenbronnen, namelijk, het verzamelen van het te onderzoeken monster van het perceel en de verwerking van het monster in het laboratorium. Momenteel is er niets of weinig bekend van de verdeling in het veld van de veroorzaker van wratziekte behalve dat er indicaties zijn dat ook dit organisme in het veld opduikt met patronen die op hotspots lijken. Ook wat betreft de betrouwbaarheid van de gehanteerde opspoeltechniek is nog te weinig bekend. Het onderzoek in onderhavig project spitst zich dan ook toe op twee onderdelen: 1- Aanzet tot bepaling van de laboratoriumfout; 2- Een eerste aanzet voor bepaling van de kleinschalige verdeling
    Decision Science : theory and applications
    Claassen, G.D.H. ; Hendriks, T.H.B. ; Hendrix, E.M.T. - \ 2007
    Wageningen, The Netherlands : Wageningen Academic Publishers (Mansholt publication series vol. 2) - ISBN 9789086860012 - 450
    besluitvorming - kwantitatieve technieken - optimalisatiemethoden - lineair programmeren - integer programmeren - dynamisch programmeren - simulatie - operationeel onderzoek - kwantitatieve methoden - beslissingsondersteunende systemen - niet-lineair programmeren - decision making - quantitative techniques - optimization methods - linear programming - integer programming - dynamic programming - simulation - operations research - quantitative methods - decision support systems - nonlinear programming
    Decision science is the discipline that is concerned with the development and applications of quantitative methods and techniques to support decision making processes. This extensively revised edition of two former versions of the book discusses the general principles and often used optimisation techniques such as linear programming, integer programming, dynamic programming, non-linear programming, network theory, simulation and stochastic programming. This book aims to fill in the gap between theory and practice. It discusses the theoretical background of important quantitative methods and techniques as well as how they can be applied to practical decision making problems. Therefore, the modeling process is illustrated with examples of firms, consumers, governments and other non-profit organisations in agriculture related sectors. The authors have used their vast didactical experience to find a proper balance between mathematical exactness, knowledge and readability on the one hand and offer understanding, insights and applicability of the subjects on the other hand. The book is therefore an essential asset in introductory courses on decision science in undergraduate, postgraduate and research programmes.
    Alternatief voor Biologische Monitoring microverontreiniging in rode aal
    Kotterman, M.J.J. ; Jongbloed, R.H. ; Hoek-van Nieuwenhuizen, M. van - \ 2007
    IJmuiden : IMARES (Rapport / Wageningen IMARES nr. C090/07) - 53
    palingen - verontreinigende stoffen - kwantitatieve technieken - bemonsteren - bioaccumulatie - biologische monitoring - eels - pollutants - quantitative techniques - sampling - bioaccumulation - biomonitoring
    Quantitative detection of Salmonella enterica and the specific interaction with Lactuca sativa
    Klerks, M.M. - \ 2007
    Wageningen University. Promotor(en): Ariena van Bruggen, co-promotor(en): Carolien Zijlstra. - [S.l.] : S.n. - ISBN 9789085046745 - 184
    lactuca sativa - slasoorten - salmonella - gastheer parasiet relaties - detectie - kwantitatieve technieken - polymerase-kettingreactie - methodologie - escherichia coli - pathogenen - uitbraken (ziekten) - gezondheid - lactuca sativa - lettuces - salmonella - host parasite relationships - detection - quantitative techniques - polymerase chain reaction - methodology - escherichia coli - pathogens - outbreaks - health
    Salmonella is among the most commonly known bacterial pathogens to cause human illness. Often Salmonellosis is associated with the consumption of contaminated foods like meat, eggs or egg products. However, during the last decades an increase of outbreaks is recognized to be caused by human pathogenic bacteria in association with fresh produce. The use of manure for production of vegetables, e.g. lettuce, contributes significantly to the risk of contamination of fresh produce. Enteric pathogens like Salmonella associated with manure can come in close contact with plants like lettuce, and a better understanding of the interaction between lettuce and Salmonella serovars during cultivation is necessary to be able to take preventive actions to reduce the risk for human health.

    This thesis describes the development of detection methods of Salmonellaenterica and Escherichia coli O157:H7 for routine diagnostic screening in the food production chain. Next to that, it describes the physiological and molecular interaction between Salmonella serovars and lettuce. Background information concerning Salmonella serovars in association with lettuce, like history of produce-associated outbreaks, approaches to detect the pathogen in food samples, pathogenesis, plant responses and the molecular interaction between plants and human pathogens, is discussed in Chapter one.

    Chapter two concerns the comparison of different molecular methods to detect S. enterica ( invA -gene) or E.coli O157:H7 ( stx -1, stx- 2 and eae -gene) with respect to sensitivity, precision and accuracy. Two basic methods were selected, both based on real-time Taqman PCR, a method that generates fluorescence upon specific DNA amplification. The increase in fluorescence during PCR is directly correlated to the amount of target DNA present after each amplification cycle. The detection and quantification methods were improved by the addition of a general internal amplification control (IAC), viz. comprised of DNA coding forgreenfluorescent protein ( gfp ), that allowed the identification of false negative results. The IAC provided insight in amplification efficiency and enabled a more accurate quantification. Implementation of the IAC did not affect the precision of the methods, although the sensitivity was reduced 10-fold. At least 1 pg of target DNA (equal to 200 CFU) was detected and quantified with high precision and accuracy. Qualitative detection was feasible even down to 10fgof target DNA (equal to 2 CFU) per reaction using both methods in which the IAC was incorporated. The methods enable a reduction in assay time to two days to test food samples, compared to five days required for the standardized procedures.

    To improve molecular methods to detect the pathogen in environmental substrates, five commercially available DNA extraction methods were evaluated in Chapter three with respect to DNA extraction efficiency of S. Enteriditis from soil, manure and compost. An internal procedural control (GIPC) for DNA extraction and amplification was developed. The GIPC was based on the same control DNA as used for the IAC in Chapter 1, incorporating gfp containing bacterial cells ( E. coli harboring a gfp-plasmid) in the sample prior to DNA extraction. Inclusion of the GIPC permitted a more accurate quantification of S. Enteriditis after DNA extraction and amplification and reduced the possibility of false-negatives. Using this protocol, the optimal extraction method differed forsoil (Mobio soil DNA extraction kit), manure (Bio101 soil DNA extraction kit) and compost (Mobio fecal DNA extraction kit).With each method, at least 2000 CFU of added S. Enteriditis/100 mg substrate could be detected bydirect DNA extraction and subsequent S. enterica specific Taqman PCR. After bacterial enrichment, as little as 1 CFU/100 mg of original substrate was detected. Using this approach a more reliable quantification was obtained for S. enterica initially present in environmental substrates.

    In Chapter four the physiological and molecular interactions between the human pathogenicS. Dublinand the commercially available mini Roman lettucecvTamburo are described. Investigation of the localization of S.Dublinon/in lettuce plants revealed the presence of significant populations on the surface and inside the plants. The latter was evidenced from significant residual concentrations after highly efficient surface disinfection (99.81%) and fluorescence microscopy ofS.Dublinin cross-sections of lettuce at the root-shoot transition region. A reduction in biomass was observed upon colonization of lettuce plants withS.Dublincompared to water-inoculated plants. Next to this physiological response, there were clear differential gene expression profiles between non-colonized and colonized lettuce plants based on transcriptome analysis by cDNA-AFLP. To confirm the results, generally and differentially expressed genes were selected, identified by sequence analysis and analyzed by RT-PCR to present the specific gene expression profiles in time. Functional grouping of the expressed genes indicated a correlation between colonization of the plants and an increase in expressed pathogenicity-related genes. From these results it was evident that lettuce plants respond to the presence ofS.Dublinat a physiological and molecular level. In addition, it was confirmed thatSalmonella serovars can colonize the interior of lettuce plants, thus potentially imposing a human health risk when contaminated lettuce is processed and consumed.

    The fact that the lettuce plants responded to the colonization by Salmonella serovars suggested that differences in susceptibility between cultivars or differences in colonization efficiency between Salmonella serovars might be present. In Chapter five, the differential interaction of S. Typhimurium, S. Enteritidis, S . Dublin, S. Newport and S. Montevideo with lettuce cultivars Cancan, Nelly and Tamburo is presented, in terms of prevalence and degree of endophytic colonization of lettuce by the Salmonella serovars. Besides a significant interaction, significant differences among serovars, but not among lettuce cultivars, were obtained when lettuce was grown under axenic conditions. When grown on soil, all three evaluated serovars S. Typhimurium, S. Enteritidis andS . Dublinwere able to colonize lettuce epiphytically, but to a lower extent than on axenically grown plants. OnlyS. Dublinwas able to colonize the plants endophytically when these were grown on contaminated soil. Species richness and diversity of the endophytic microbial community, determined from DGGE gels with DNA from Salmonella -colonized lettuce Cancan and Nelly, were negatively correlated with the number of Salmonella CFU / gram of lettuce. No correlation was observed for cultivar Tamburo. Thus, the microflora of lettuce cultivars Cancan and Nelly appeared more antagonistic to Salmonella serovars than that of cultivar Tamburo.

    Besides plant-associated colonization, also the active movement of Salmonella serovars towards lettuce roots was assessed. Movement was visualized using a metabolism marker (tetrazolium) for chemotaxis. Reduction of this marker suggested the presence of an organic compound in the lettuce root exudates that was used as carbon source by the Salmonella serovars. Subsequent micro-array analyses with DNA extracted from a broth culture of Salmonella with or without exudates identified genes of S. Typhimurium that were induced by root exudates. These genes, trehalose-6-phosphate synthase ( Ots A; utilizes glucose-6-phosphate as substrate), hexose phosphate utilization protein ( Uhp C; sensor for external glucose-6-phosphate), putative effector protein ( Ssa H; regulator of secretion of the type III secretion system),and putative anti-silencer RNA( Drs A; regulator of transcription to express rcs A promoter, responsible for capsular polysaccharide synthesis), imply a relation with a sugar-like carbon source and thus suggest an association with chemotaxis. The results described in Chapter 5 reveal different plant and microbial factors that influence the colonization efficiency of Salmonella serovars. The serovar and cultivar, but indirectly also the rhizosphere and the endophytic microflora of lettuce were most influential with respect to the risk of colonization and thus the risk for human health.

    Finally, an extensive discussion concerning the research of Chapters two to five is described in Chapter six, including future perspectives of risk for human health, route of infection and risk reduction in the production chain of Salmonella -associated lettuce.
    Met NIRS productieproces en productkwaliteit bewaken : snelle kwaliteitscontrole voor vlees op de werkvloer
    Schreutelkamp, F. ; Vedder, H.W. - \ 2002
    Vleesindustrie 2002 (2002)8. - ISSN 1385-7312 - p. 26 - 27,29.
    kwantitatieve analyse - kwantitatieve technieken - infraroodspectroscopie - vee- en vleesindustrie - vlees - statistiek - productieprocessen - kwaliteitszorg - quantitative analysis - quantitative techniques - infrared spectroscopy - meat and livestock industry - meat - statistics - production processes - quality management
    Het werken met Nabij InfraRood Spectroscopie vereist professionele kennis en praktische ervaring met deze techniek. Statistische procescontrôle in combinatie met snelle sensoren leidt tot meer inzicht in en grip op het productieproces
    Ontwikkeling van een methode voor de scheiding van fosfaatpools uit zand-, klei- en veengronden
    Lepelaar, P. ; Schoumans, O.F. - \ 1999
    Wageningen : Staring Centrum (Rapport / DLO-Staring Centrum 575) - 73
    grondanalyse - kwantitatieve technieken - fosfor - adsorptie - soil analysis - quantitative techniques - phosphorus - adsorption
    Om vast te stellen in welke vormen het fosfaat in verschillende grondsoorten wordt opgehoopt, is nagegaan welke extractiemethodiek in de praktijk goed hanteerbaar blijkt te zijn en daarnaast ook goed aansluit bij de huidige visie omtrent fosfaatvastlegging in de bodem. Met behulp van vier verschillende extracties (infinite-sink methode, oxalaatextractie, zoutzuurdestructie met en zonder oxydatie) worden de belangrijkste fosfaatvormen op relatief eenvoudige wijze uit de bodem geëxtraheerd. De geëxtraheerde bodemfosfaten vertegenwoordigen: makkelijk desorbeerbaar fosfaat, gesorbeerd fosfaat, mineraal fosfaat en totaal fosfaat (mineraal fosfaat + organisch gebonden fosfaat).Vergelijking van het gebruik van een sequentiële methodiek met die van een parallelle methodiek toont aan dat de parallelle methodiek nauwkeuriger en betrouwbaarder is.
    Extractie- en opwerkingsmethoden voor bestrijdingsmiddelen in water, grond en waterbodem : voorstudie voor normalisatie van meetmethoden
    Harmsen, J. ; Berg, H. van den - \ 1997
    Wageningen : DLO-Staring Centrum (Rapport / DLO-Staring Centrum 530) - 51
    chemische analyse - analytische methoden - water - bepaling - verontreinigende stoffen - pesticiden - pesticidenresiduen - persistentie - grondanalyse - kwantitatieve technieken - kwaliteitsnormen - waterbodems - chemical analysis - analytical methods - water - determination - pollutants - pesticides - pesticide residues - persistence - soil analysis - quantitative techniques - quality standards - water bottoms
    De relatie tussen de bodemvruchtbaarheidsparameters Pw- en P-AL-getal, en fosfaatverzadiging bij zandgronden
    Schoumans, O.F. ; Breeuwsma, A. ; Bachrioui - Louwerse, A. El - \ 1991
    Wageningen : DLO-Staring Centrum (Rapport / DLO-Staring Centrum 112) - 67
    nederland - fosfor - kwantitatieve technieken - zandgronden - bodem - grondanalyse - bodemoplossing - netherlands - phosphorus - quantitative techniques - sandy soils - soil - soil analysis - soil solution
    De invloed van verschillende bepalingsmethoden op de CEC van zandgronden
    Heijnen, M.M.T. - \ 1991
    Wageningen : DLO-Staring Centrum (Rapport / DLO-Staring Centrum 139) - 57
    kationenuitwisselingcapaciteit - kwantitatieve technieken - zandgronden - grondanalyse - bodemkunde - bodemoplossing - cation exchange capacity - quantitative techniques - sandy soils - soil analysis - soil science - soil solution
    Rapid column experiments to study replacement of exchangeable cations in soil samples.
    El-Guindy, S. ; Harmsen, J. - \ 1989
    Netherlands Journal of Agricultural Science 37 (1989)3. - ISSN 0028-2928 - p. 213 - 225.
    cation exchange capacity - quantitative techniques - soil analysis - soil science - soil solution
    Impact of acid atmospheric deposition on soils : quantification of chemical and hydrologic processes
    Grinsven, J.J.M. van - \ 1988
    Agricultural University. Promotor(en): N. van Breemen; F.A.M. de Haan. - S.l. : Van Grinsven - 213
    neerslag - chemische eigenschappen - zuurgraad - zure regen - bosbouw - verzuring - bodem ph - bodemaciditeit - zure depositie - grondanalyse - bodemoplossing - kwantitatieve technieken - computersimulatie - simulatie - simulatiemodellen - precipitation - chemical properties - acidity - acid rain - forestry - acidification - soil ph - soil acidity - acid deposition - soil analysis - soil solution - quantitative techniques - computer simulation - simulation - simulation models

    Atmospheric deposition of SO x , NOx and NHx will cause major changes in the chemical composition of solutions in acid soils, which may affect the biological functions of the soil. This thesis deals with quantification of soil acidification by means of chemical budgets, kinetics of mineral weathering of aluminum and base cations, and simulation of soil acidification. Most results apply to an acid forest soil on the Hackfort estate, for which monitoring data were available from 1981 to 1987.

    Spatial variability of soil solution composition was found to be the dominant source of uncertainty in determining chemical budgets. Uncertainty in annual chemical budgets due to simulation of unsaturated soil water fluxes generally does not exceed 10%. A new method was developed for in situ measurement of unsaturated soil water fluxes at a similar accuracy as obtained by numerical simulation.

    Weathering of Al is the dominant process for proton buffering in acid soils. In dutch acid soils, the most reactive pool for Al is present in hydrated oxides, often in association with organic matter. On average the weathering rate of Al increases nearly proportional with (H +), and decrease strongly with increasing depletion of reactive Al. Total exhaustion of the reactive pool of hydrated oxides may become a problem in the coming century.

    A new column percolation technique was developed to measure weathering rates at controlled pH in absence of mechanical disturbance. In all cases base cation weathering rates from laboratory experiments were considerably higher than estimated ' from field mass balance studies. A yet unconsidered effect for explanation of this discrepancy, is the increase of weathering rate with (by approximation the square root of) the percolation rate. Moreover, evidence was found that assumed patchy coatings of secondary Al may be protective against weathering of Ca from plagioclases.

    The ILWAS model was adapted for simulation of soil acidification. The model proved to be appropriate to simulate annual budgets and seasonal variation of concentrations for all major components. Concentration peaks near the end of summer appeared to be overestimated, but also scarce field observations may be biased. The model seemed somewhat too crude to predict N-dynamics. The model was used to analyze the response of the soil system to 50% reduction of deposition, fertilization, and removal of forest vegetation. Scenario analyses, demonstrated that pH is not a sensitive indicator for changes in soil chemistry. Simple models, using large time steps, may be adequate to evaluate average annual changes of soil solution characteristics over periods of several decades.

    Establishment of fertilizer recommendations on the basis of soil tests
    Smilde, K.W. - \ 1985
    Haren (Gr.) : I.B. (Rapport / Instituut voor Bodemvruchtbaarheid no. 17-85) - 24
    toedieningshoeveelheden - mestbehoeftebepaling - kunstmeststoffen - kwantitatieve technieken - grondanalyse - bodemoplossing - application rates - fertilizer requirement determination - fertilizers - quantitative techniques - soil analysis - soil solution
    De aspecten die samenhangen met het oordeelkundig toedienen van kunstmest zijn uiteengezet. In veel landen ontbreekt een gezonde basis voor kunstmesttoediening welke ondermeer gebaseerd moet zijn op bodemonderzoek en plantanalyse
    Vergelijking van de fosfaat-schudmethode met de fosfato-statmethode
    Schoumans, O.F. ; Koning, R.A. - \ 1985
    Wageningen : STIBOKA (Rapport / Stichting voor Bodemkartering nr. 1867) - 32
    bodem - fosfor - absorptie - adsorptie - grondanalyse - bodemoplossing - kwantitatieve technieken - soil - phosphorus - absorption - adsorption - soil analysis - soil solution - quantitative techniques
    Een veldmethode voor de bepaling van het potentiele en aktuele zuurgehalte van de grond ten behoeve van bodemkartering en landevaluatie in gebieden met potentiele en aktuele sulfaat-zure gronden
    Konsten, C.J.M. - \ 1984
    Wageningen : STIBOKA (Interne mededeling / Stichting voor Bodemkartering no. 67) - 51
    grondanalyse - bodemoplossing - kwantitatieve technieken - bodemkarteringen - kaarten - zure gronden - kattekleigronden - soil analysis - soil solution - quantitative techniques - soil surveys - maps - acid soils - acid sulfate soils
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