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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    Evidence for an unidentified non-photochemical ground-level source of formaldehyde in the Po Valley with potential implications for ozone production
    Kaiser, J. ; Wolfe, G.M. ; Bohn, B. ; Ganzeveld, L.N. - \ 2015
    Atmospheric Chemistry and Physics 15 (2015). - ISSN 1680-7316 - p. 1289 - 1298.
    volatile organic-compounds - exchange cafe model - total oh reactivity - tropospheric degradation - chemical mechanism - gas-phase - part - atmosphere - forest - hydrocarbons
    Ozone concentrations in the Po Valley of northern Italy often exceed international regulations. As both a source of radicals and an intermediate in the oxidation of most volatile organic compounds (VOCs), formaldehyde (HCHO) is a useful tracer for the oxidative processing of hydrocarbons that leads to ozone production. We investigate the sources of HCHO in the Po Valley using vertical profile measurements acquired from the airship Zeppelin NT over an agricultural region during the PEGASOS 2012 campaign. Using a 1-D model, the total VOC oxidation rate is examined and discussed in the context of formaldehyde and ozone production in the early morning. While model and measurement discrepancies in OH reactivity are small (on average 3.4 ± 13%), HCHO concentrations are underestimated by as much as 1.5 ppb (45%) in the convective mixed layer. A similar underestimate in HCHO was seen in the 2002–2003 FORMAT Po Valley measurements, though the additional source of HCHO was not identified. Oxidation of unmeasured VOC precursors cannot explain the missing HCHO source, as measured OH reactivity is explained by measured VOCs and their calculated oxidation products. We conclude that local direct emissions from agricultural land are the most likely source of missing HCHO. Model calculations demonstrate that radicals from degradation of this non-photochemical HCHO source increase model ozone production rates by as much as 0.6 ppb h-1 (12%) before noon.
    Constraints and potentials of future irrigation water availability on agricultural production under climate change
    Elliott, J. ; Deryng, D. ; Muller, C. ; Frieler, K. ; Konzmann, M. ; Gerten, D. ; Glotter, M. ; Florke, M.F. ; Wada, Y. ; Ludwig, F. - \ 2014
    Proceedings of the National Academy of Sciences of the United States of America 111 (2014)9. - ISSN 0027-8424 - p. 3239 - 3244.
    model description - requirements - food - scarcity - impacts - part
    We compare ensembles of water supply and demand projections from 10 global hydrological models and six global gridded crop models. These are produced as part of the Inter-Sectoral Impacts Model Intercomparison Project, with coordination from the Agricultural Model Intercomparison and Improvement Project, and driven by outputs of general circulation models run under representative concentration pathway 8.5 as part of the Fifth Coupled Model Intercomparison Project. Models project that direct climate impacts to maize, soybean, wheat, and rice involve losses of 400–1,400 Pcal (8–24% of present-day total) when CO2 fertilization effects are accounted for or 1,400–2,600 Pcal (24–43%) otherwise. Freshwater limitations in some irrigated regions (western United States; China; and West, South, and Central Asia) could necessitate the reversion of 20–60 Mha of cropland from irrigated to rainfed management by end-of-century, and a further loss of 600–2,900 Pcal of food production. In other regions (northern/eastern United States, parts of South America, much of Europe, and South East Asia) surplus water supply could in principle support a net increase in irrigation, although substantial investments in irrigation infrastructure would be required.
    The policy-relevancy of impact assessment tools: Evaluating nine years of European research funding
    Podhora, A. ; Helming, K. ; Adenauer, L. ; Heckelei, T. ; Kautto, P. ; Reidsma, P. ; Rennings, K. ; Turnpenny, J. ; Jansen, J.M.L. - \ 2013
    Environmental Science & Policy 31 (2013). - ISSN 1462-9011 - p. 85 - 95.
    affecting land-use - of-the-art - integrated assessment - sustainable development - agricultural systems - analytical framework - union - part
    Since 2002, the European Commission has employed the instrument of ex-ante impact assessments (IA) to help focus its policy-making process on implementing sustainable development. Scientific tools should play an essential role of providing the evidence base to assess the impacts of alternative policy options. To identify the contribution of research funding for IA tool development, this paper analysed the variety of IA tools designed in projects funded by European Framework Programmes (FPs) 6 and 7. The paper is based on project information available on the European Cordis website, individual project websites and a verification of the results by the project coordinators. We analysed the projects from the interests of IA practitioners as tool users (European policy and impact areas addressed by the tools, jurisdictional application levels and tool categories). Out of the 7.781 projects funded in FP6 and FP7, 203 could be identified that designed tools for the IA process. Nearly half of them applied to environmental, agricultural and transport policy areas. Within these areas, the tools primarily addressed environmental impact areas, less economic and least social impact areas. The IA tools focused on European policies. Models represented the largest tool category, whereas approximately half of the tools could not be clearly categorized. Concerning our analysis criteria, the tool descriptions available on the internet were often unclear and thus may limit the application potential of the tools because of a mismatch of technical terms and categorisation criteria between tool providers and tool users. Future IA tools require a joint political and scientific typology and a narrowing of the gaps, e.g., with view to multi-jurisdictional application and a clear reference to the steps of the IA process.
    Landscape Scenarios and Multifunctionality: Making Land Use Impact Assessment Operational
    Helming, K. ; Perez-Soba, M. - \ 2011
    Ecology and Society 16 (2011)1. - ISSN 1708-3087
    analytical framework - policies - stakeholders - tools - part
    Ex ante impact assessment can help in structuring the analysis of human-environment interactions thereby supporting land use decision making for sustainable development. The contributions to this special feature focus on some of the challenges of making land use impact assessment operational for policy making. A total of nine papers deal with the needs and uses of assessment tools for policy making at the European level, with the value-based influence in scenario development, and with ex ante impact assessment studies in different contexts, spatial systems, and for different purposes and user groups. The concept of landscape multifunctionality was implicitly or explicitly employed as an integrating entity between socioeconomic and biogeophysical features of a spatial system. Three major aspects were revealed that could improve the relevance of the policy of land use impact assessment: the involvement of decision makers early on in the design of the impact assessment study; the integration of quantitative analysis with participatory valuation methods; and the robust and transparent design of the analytical methods.
    Mapping soil clay contents in Dutch marine districts using gamma-ray spectrometry
    Klooster, E. van der; Egmond, F.M. van; Sonneveld, M.P.W. - \ 2011
    European Journal of Soil Science 62 (2011)5. - ISSN 1351-0754 - p. 743 - 753.
    plant-available potassium - radiometric data - water-content - topsoil - netherlands - sediments - spectra - models - part
    Conventional soil sampling methods to obtain high-resolution soil data are labour intensive and costly. Recently, gamma ray spectrometry has emerged as a promising technique to overcome these obstacles. The objective of our study was to investigate the prediction of soil clay contents using gamma-ray spectrometry in three marine clay districts in the Netherlands: the southwestern marine district (SMD), the IJsselmeerpolder district (IJPD) and the northern marine district (NMD). The performance of linear regression models was investigated at field (1000 km2) scales and for all the Dutch marine districts together. For this study, a database was available with 1371 gamma-ray spectra measured on arable fields in marine clay districts during the period 2005–2008 and these were all linked to laboratory analyses of clay contents. At the field scale, linear regression models based on 40K, 232Th, or a combination of these revealed much smaller root mean squared error (RMSE) values (2–3%) compared with a model based on the field mean (8–10%). At the district scale, the regression models for the SMD and IJPD, which have comparable sediments, performed better than for the NMD. This indicates that the prediction of clay contents in late Holocene marine sediments may be made with gamma-ray spectrometry provided that the origin of the parent material results in a unique fingerprint. Because of the heterogeneous parent material of all marine districts taken together, our study shows that no unique and precise fingerprint exists, and the RMSE of 6% between clay contents and gamma-ray spectra is not much different from the RMSE of 7% when using the overall mean as a predictor.
    Bio-reduction of pyrite investigated in a gas lift loop reactor
    Hol, A. ; Weijden, R.D. van der; Weert, G. van; Kondos, P. ; Buisman, C.J.N. - \ 2010
    International Journal of Mineral Processing 94 (2010)3-4. - ISSN 0301-7516 - p. 140 - 146.
    bearing arsenian pyrite - gold - oxidation - bioreactor - minerals - progress - part
    To liberate gold from refractory pyrite, oxidative destruction techniques that consume lots of energy and generate acidic waste streams are custom. As an alternative the “bio-reduction” of pyrite is proposed and investigated in this study. Bio-reduction is an anaerobic process based on sulfate/sulfur reducing bacteria which are thought to be able to use pyrite-sulfur as a possible electron acceptor. The conversion of pyrite-sulfur into hydrogen sulfide is advantageous because energy is saved and the generation of an acidic waste stream is prevented. In addition, the generated H2S can be used to produce elemental sulfur, or even gold lixiviants such as thiosulfate or bisulfide. Batch experiments under anaerobic conditions showed that two effects can inhibit bio-reduction; methane formation and sulfide accumulation. In a gas lift loop reactor operated at pH 5, temperature of 35 °C, and with continuous sulfide removal no evidence of pyrite bio-reduction was found. Though the sulfate reducing bacteria survived, they did not utilize pyrite-sulfur as an electron acceptor under the chosen conditions.
    Synthesis of semantic modelling and risk analysis methodology applied to animal welfare
    Bracke, M.B.M. ; Edwards, S.A. ; Metz, J.H.M. ; Noordhuizen, J.P.T.M. ; Algers, B. - \ 2008
    Animal 2 (2008)7. - ISSN 1751-7311 - p. 1061 - 1072.
    decision-support-system - environmental enrichment - pigs - part - behavior - criteria - calves
    Decision-making on animal welfare issues requires a synthesis of information. For the assessment of farm animal welfare based on scientific information collected in a database, a methodology called `semantic modelling¿ has been developed. To date, however, this methodology has not been generally applied. Recently, a qualitative Risk Assessment approach has been published by the European Food Safety Authority (EFSA) for the first time, concerning the welfare of intensively reared calves. This paper reports on a critical analysis of this Risk Assessment (RA) approach from a semantic-modelling (SM) perspective, emphasizing the importance of several seemingly self-evident principles, including the definition of concepts, application of explicit methodological procedures and specification of how underlying values and scientific information lead to the RA output. In addition, the need to include positive aspects of welfare and overall welfare assessments are emphasized. The analysis shows that the RA approach for animal welfare could benefit from SM methodology to support transparent and science-based decision-making.
    Animal based parameters are no panacea for on-farm monitoring of animal welfare
    Bracke, M.B.M. - \ 2007
    Animal Welfare 16 (2007)2. - ISSN 0962-7286 - p. 229 - 231.
    decision-support-system - housing systems - semantic model - part - needs - risk - pigs
    On-farm monitoring of animal welfare is an important, present-day objective in animal welfare science. Scientists tend to focus exclusively on animal-based parameters, possibly because using environment-based parameters could be begging the question why welfare has been affected and because animal-based parameters would be better indicators of welfare. However, selection of even the best animal-based parameters that have conventionally been used in experiments could have unacceptable consequences. Systems that are generally considered to be poor welfare systems may generate unacceptably high welfare scores. The monitoring systems could fail to match basic intuitions in society and the scientific community. In order to avoid this problem, available knowledge, eg about animal motivation derived from consumer demand studies and knowledge about the natural behaviour of the animals, should be used explicitly in welfare assessment. This requires making welfare inferences from knowledge about the relationships between environment-based and animal-based parameters using standard operating procedures. The on-farm measurement of animal-based parameters may be regarded as the measurement of critical control points, which must be compared and reconciled with predictions based on available scientific knowledge. For this purpose the formalisation of welfare assessment should be developed further.
    Comparison of techniques for estimating herbage intake by grazing dairy cows
    Smit, H.J. ; Taweel, H.Z. ; Tas, B.M. ; Tamminga, S. ; Elgersma, A. - \ 2005
    Journal of Dairy Science 88 (2005)5. - ISSN 0022-0302 - p. 1827 - 1836.
    n-alkane concentrations - cuticular wax - pasture plants - forage intake - markers - herbivores - ruminants - nutrition - sheep - part
    For estimating herbage intake during grazing, the traditional sward cutting technique was compared in grazing experiments in 2002 and 2003 with the recently developed n-alkanes technique and with the net energy method. The first method estimates herbage intake by the difference between the herbage mass before and after grazing and the regrowth between the 2 points in time. The second technique estimates herbage intake by the ratio of a dosed even-chain synthetic n-alkane (C32) and a naturally occurring odd-chain n-alkane (C31 or C33) in the herbage and feces. The third technique calculated the intake from the animal's energy requirements for milk production and maintenance. The sward cutting technique estimated herbage intake with the highest coefficient of variation and had different results in the 2 experimental years. The n-alkanes method yielded less variable results, whereas the net energy method gave the least variable results. In 2002, the estimates of the alkane ratio C32:C33 were best related with estimations of the net energy method. In 2003, the estimates of the alkane ratio C32:C31 were best related. The estimate based on the alkane ratio C32:C33 had a lower coefficient of variation than the one based on the alkane ratio C32:C31. Therefore, the C32:C33 alkane method was considered to be a better direct estimator for herbage intake by grazing lactating dairy cows
    Correlation between late blight resistance and foliage maturity type in potato
    Visker, M.H.P.W. ; Raaij, H.M.G. van; Keizer, L.C.P. ; Struik, P.C. ; Colon, L.T. - \ 2004
    Euphytica 137 (2004)3. - ISSN 0014-2336 - p. 311 - 323.
    tuberosum breeding program - phytophthora-infestans - solanum-tuberosum - field-resistance - general resistance - progeny tests - inheritance - parents - markers - part
    The genetics of race-non-specific foliage resistance against Phytophthora infestans, of foliage maturity type, and of their association in potato (Solanum tuberosum) were studied. Six progenies were derived from a half-diallel set of crosses between diploid potato clones that represented a broad pool within the genus Solanum and were free of any of the 11 known R genes for late blight resistance. The progenies were evaluated for resistance to late blight and for foliage maturity type, and five of them showed a significant correlation between the two traits. The correlation did not account for all variation that was present for both traits, as reflected in the analysis in which the relative AUDPC values were adjusted for foliage maturity type. The present study adds to previous results: resistance against P. infestans always coincides with late foliage maturity. However, the results also indicate that some selection for late blight resistance without affecting the foliage maturity type should be possible.
    Effect of sucrose on adventitious root regeneration in apple
    Calamar, A. ; Klerk, G.J.M. de - \ 2002
    Plant Cell, Tissue and Organ Culture: an international journal on in vitro culture of higher plants 70 (2002)2. - ISSN 0167-6857 - p. 207 - 212.
    forming tobacco callus - somatic embryogenesis - developing cotyledons - starch accumulation - auxin - part
    We have examined the effect of sucrose on adventitious root formation in apple microcuttings and in 1-mm stem slices cut from apple microcuttings. The sucrose concentration influenced the number of adventitious roots, but at a broad range of sucrose concentrations (1¿9%) the effect was small. In addition, there was an interaction between sucrose and auxin: increasing the sucrose concentration shifted the dose¿response curve of auxin to the right. When slices were cultured on medium without sucrose for the initial period (0¿48 h), rooting was reduced whereas 48-h culture without application of sucrose had hardly any effect or even a slight promotive effect in a later period (48¿120 h). The results show that during adventitious root formation, applied sucrose is used as a source of energy and building blocks but they are also in accordance with a possible regulatory role of sucrose
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