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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Bioturbation and erosion rates along the soil-hillslope conveyor belt, part 2: Quantification using an analytical solution of the diffusion–advection equation
Román-Sánchez, Andrea ; Laguna, Ana ; Reimann, Tony ; Giráldez, Juan Vicente ; Peña, Adolfo ; Vanwalleghem, Tom - \ 2019
Earth Surface Processes and Landforms 44 (2019)10. - ISSN 0197-9337 - p. 2066 - 2080.
bioturbation - critical zone - deposition - diffusivity - erosion - feldspar luminescence dating - sensitivity and uncertainty - soil formation

Particles on soil-mantled hillslopes are subject to downslope transport by erosion processes and vertical mixing by bioturbation. Both are key processes for understanding landscape evolution and soil formation, and affect the functioning of the critical zone. We show here how the depth–age information, derived from feldspar-based single grain post-infrared infrared stimulated luminescence (pIRIR), can be used to simultaneously quantify erosion and bioturbation processes along a hillslope. In this study, we propose, for the first time, an analytical solution for the diffusion–advection equation to calculate the diffusivity constant and erosion–deposition rates. We have fitted this model to age–depth data derived from 15 soil samples from four soil profiles along a catena located under natural grassland in the Santa Clotilde Critical Zone Observatory, in the south of Spain. A global sensitivity analysis was used to assess the relative importance of each model parameter in the output. Finally, the posterior probability density functions were calculated to evaluate the uncertainty in the model parameter estimates. The results show that the diffusivity constant at the surface varies from 11.4 to 81.9 mm2 a-1 for the hilltop and hill-base profile, respectively, and between 7.4 and 64.8 mm2 a-1 at 50 cm depth. The uncertainty in the estimation of the erosion–deposition rates was found to be too high to make a reliable estimate, probably because erosion–deposition processes are much slower than bioturbation processes in this environment. This is confirmed by a global sensitivity analysis that shows how the most important parameters controlling the age–depth structure in this environment are the diffusivity constant and regolith depth. Finally, we have found a good agreement between the soil reworking rates proposed by earlier studies, considering only particle age and depth, and the estimated diffusivity constants. The soil reworking rates are effective rates, corrected for the proportion of particles actually participating in the process.

Voortgang realisatie nationaal natuurbeleid : technische achtergronden van een aantal indicatoren uit de digitale Balans van de Leefomgeving 2016
Sanders, M.E. ; Wamelink, G.W.W. ; Wegman, R.M.A. ; Clement, J. - \ 2016
Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-technical report 79) - 74
ecologische hoofdstructuur - ecologie - ecosystemen - verdroging (milieu) - verzuring - depositie - natuurbeleid - ecological network - ecology - ecosystems - groundwater depletion - acidification - deposition - nature conservation policy
The Dutch government is, together with its partners, taking measures to create a coherent network ofprotected nature areas and to improve environmental conditions. This in order to halt the decline in the areaof natural habitat and biodiversity and to improve their conservation status. The Government wants to stayinformed on the progress of this policy. The Netherlands Environmental Assessment Agency (PBL) has selectedindicators that should provide answers to the question: ‘What is the progress of the policy measures taken,especially for realising the nature network, improving the nature quality and the environmental conditions aswell?’ The selected indicators have been updated and analysed in order to assess this progress. This reportdescribes the results of the policy measures taken on the basis of the indicators, the technical setting of thedata and methods used to bring these indicators up to date and the reliability and acceptability of it
30 vragen en antwoorden over zwavel
Schils, René - \ 2016
Wageningen : Alterra, Wageningen-UR - 68
zwavel - zwavelmeststoffen - bemesting - uitspoelen - depositie - sulfur - sulfur fertilizers - fertilizer application - leaching - deposition
Het Ministerie van Economische Zaken heeft de Commissie van Deskundigen Meststoffenwet gevraagd de belangrijkste vragen en antwoorden over zwavel op toegankelijke wijze te beschrijven. Deze publicatie brengt het onderwerp zwavel voor het voetlicht.
Functionele diversiteit mycorrhizaschimmels onder druk door stikstofdepositie
Ozinga, W.A. ; Kuijper, Thomas - \ 2015
Vakblad Natuur Bos Landschap 12 (2015)117. - ISSN 1572-7610 - p. 20 - 22.
mycorrhizaschimmels - functionele biodiversiteit - stikstof - stikstofkringloop - depositie - ecosystemen - bosgebieden - mycorrhizal fungi - functional biodiversity - nitrogen - nitrogen cycle - deposition - ecosystems - woodlands
Bosbodems kunnen veel verschillende ectomycorrhiza-vormende schimmels herbergen. In de herfst is een glimp van deze ondergrondse rijkdom te zien via de vorming van vruchtlichamen (‘paddenstoelen’). De ectomycorrhizaschimmels spelen een belangrijke rol bij onder andere de nutriëntenkringloop, de vastlegging van koolstof en de natuurlijke regeneratie van bomen. Hoge stikstofgehaltes in de bodem leiden echter tot een sterke afname van de abundantie en diversiteit aan mycorrhizaschimmels en dit kan doorwerken in het hele ecosysteem.
Effecten van landschapselementen op de ammoniakdepositie in Natura 2000- gebieden
Kros, J. ; Gies, T.J.A. ; Voogd, J.C.H. ; Vries, Wilco de; Aben, Jan ; Pul, Addo - \ 2015
Alterra, Wageningen-UR (Alterra-rapport 2689) - 37 p.
landschapselementen - landschap - ammoniak - depositie - overijssel - landscape elements - landscape - ammonia - deposition
Om het mogelijke effect van het aanbrengen van landschapselementen op de NHx (NH3 + NH4 +) depositie op Natura 2000-gebieden in te schatten, is door Alterra een aantal indicatieve berekeningen uitgevoerd voor de gehele provincie Overijssel. De berekeningen zijn uitgevoerd met het OPS-model van het RIVM. Het aanbrengen van een landschapselement van 50m breed rondom bedrijven, lijkt van de doorgerekende scenario’s het meestbelovend.
Effect of protein provision via milk replacer or solid feed on protein metabolism in veal calves
Berends, H. ; Borne, J.J.G.C. van den; Røjen, B.A. ; Hendriks, W.H. ; Gerrits, W.J.J. - \ 2015
Journal of Dairy Science 98 (2015)2. - ISSN 0022-0302 - p. 1119 - 1126.
heavy preruminant calves - amino-acids - energy-metabolism - rumen development - dairy-cattle - nitrogen - urea - growth - performance - deposition
The current study evaluated the effects of protein provision to calves fed a combination of solid feed (SF) and milk replacer (MR) at equal total N intake on urea recycling and N retention. Nitrogen balance traits and [15N2]urea kinetics were measured in 30 calves (23 wk of age, 180 ± 3.7 kg of body weight), after being exposed to the following experimental treatments for 11 wk: a low level of SF with a low N content (SF providing 12% of total N intake), a high level of SF with a low N content (SF providing 22% of total N intake), or a high level of SF with a high N content (SF providing 36% of total N intake). The SF mixture consisted of 50% concentrates, 25% corn silage, and 25% straw on a dry matter basis. Total N intake was equalized to 1.8 g of N·kg of BW-0.75·d-1 by adjusting N intake via MR. All calves were housed individually on metabolic cages to allow for quantification of a N balance of calves for 5 d, and for the assessment of urea recycling from [15N2]urea kinetics. Increasing low-N SF intake at equal total N intake resulted in a shift from urinary to fecal N excretion but did not affect protein retention (0.71 g of N·kg of BW-0.75·d-1). Increasing low-N SF intake increased urea recycling but urea reused for anabolism remained unaffected. Total-tract neutral detergent fiber digestibility decreased (-9%) with increasing low-N SF intake, indicating reduced rumen fermentation. Increasing the N content of SF at equal total N intake resulted in decreased urea production, excretion, and return to ornithine cycle, and increased protein retention by 17%. This increase was likely related to an effect of energy availability on protein retention due to an increase in total-tract neutral detergent fiber digestion (>10%) and due to an increased energy supply via the MR. In conclusion, increasing low-N SF intake at the expense of N intake from MR, did not affect protein retention efficiency in calves. Increasing the N content of SF at equal total N intake decreased urea production, increased protein retention, and coincided with improved fiber degradation. Therefore, results suggest that low N availability in the rumen limits microbial growth and rumen fermentation in calves fed low-N SF (93 g of CP/kg of DM), and this effect cannot be compensated for by recycling of urea originating from MR.
Influence of adjuvants on the deposition of mancozeb
Schepers, H.T.A.M. ; Evenhuis, A. ; Topper, C.G. - \ 2014
Wageningen : Wageningen UR (vegIMPACT report 5) - 14
solanum tuberosum - aardappelen - plantenziekten - oömycota - phytophthora infestans - fungiciden - mancozeb - hulpstoffen - depositie - indonesië - potproeven - nederland - potatoes - plant diseases - oomycota - fungicides - adjuvants - deposition - indonesia - pot experimentation - netherlands
Soil inorganic carbon stock under different soil types and land uses on the Loess Plateau region of China
Tan, W.F. ; Zhang, R. ; Cao, H. ; Huang, C.Q. ; Yang, Q.K. ; Wang, M.K. ; Koopal, L.K. - \ 2014
Catena 121 (2014). - ISSN 0341-8162 - p. 22 - 30.
organic-carbon - storage - sequestration - grasslands - deposition - dynamics - patterns - nitrogen - climate - caliche
The soil carbon reservoir is the largest carbon reservoir in terrestrial ecosystems and consists of soil organic and inorganic carbon stocks. Previous studies have mainly focused on the soil organic carbon (SOC) stock, and limited information is available about the soil inorganic carbon (SIC) stock. The Chinese Loess Plateau (CLP), which is located in the arid and semi-arid region of China, is an important inorganic carbon reservoir, with a thick soil layer that is rich in calcium carbonate. However, there are few reports on the SIC stock and its spatial distribution in this region. In the current study, the SIC densities and stocks for various soil types and land use patterns were evaluated based on 495 profiles with 2470 soil samples across the CLP, which were collected from the Chinese Second National Soil Survey. The results showed that in the top 1 m of soil across the CLP, the average SIC density is 17.04 kg/m(2), and the total SIC stock is approximately 10.20 Pg C (1 Pg = 10(15) g). The SIC stock of the CLP accounts for approximately 18.4% of the total SIC stock throughout China. The average values of the SIC stock in the 0-20, 20-50 and 50-100 cm depths of the CLP are 2.39, 2.92 and 4.89 Pg, respectively. Under different land use patterns, the order of the average SIC density is farmland approximate to grassland > forest in all soil layers. For the various soil types, the SIC density in the 0-100 cm layer is the highest in alkaline soil and lowest in subalpine meadow soil, whereas the SIC stock is highest in loessial soil, eolian sandy soil and sierozem, and the lowest in subalpine meadow soil. These differences are largely a result of the area occupied by each soil type and the climate conditions. The results of this study provide basic information about carbon reservoir in China and contribute to our understanding of the SIC stock on the CLP as it relates to the carbon balance of terrestrial ecosystems. (C) 2014 Elsevier B.V. All rights reserved.
Anti-browning and barrier properties of edible coatings prepared with electrospraying
Khan, M.K.I. ; Cakmak, I. ; Tavman, S. ; Schutyser, M.A.I. ; Schroen, C.G.P.H. - \ 2014
Innovative Food Science and Emerging Technologies 25 (2014). - ISSN 1466-8564 - p. 9 - 13.
shelf-life - fresh - deposition - improve
Electrospraying is a novel technique for the application of coating to foods. In this study, thin lipid-based coatings were prepared by electrospraying on model surface and evaluated for their moisture barrier functionality. Sunflower oil and chocolate based coating materials were electrosprayed at elevated temperature (60 °C) using a multiple nozzle system. Sunflower oil coated the sides and top surface of the target surfaces, while chocolate based material deposited primarily on the top surface. In chocolate based coatings, larger droplet size and related lower charge to mass ratio explained the limited “wrap-around effect”. Sunflower oil based coating penetrated into the target surfaces, which could be reduced by the addition of stearic acid (up to 0.15 g/g). However, this addition resulted in crystallization and crack formation during storage, and ultimately reduced barrier functionality. Conversely, chocolate-based material produced thicker coatings (up to 0.3 mm), which were more stable during storage and exhibited enhanced barrier properties. Industrial relevance: Electrospraying is an efficient coating technique which can reduce the processing costs for industrial processes. This technique has been successfully applied to increase the shelf life of a minimally processed food. The results found in this study can be used at industry to obtain food products with desiredsensory attributes along with prolonged shelf life.
Utilization of geometrci light trapping in thin film silicon solar cells: simulations and experiments
Jong, M.M. de; Sonneveld, P.J. ; Baggerman, J. ; Rijn, C.J.M. van; Rath, J.K. ; Schropp, R.E.I. - \ 2014
Progress in Photovoltaics 22 (2014)5. - ISSN 1062-7995 - p. 540 - 547.
microcrystalline silicon - amorphous polymers - temperature - deposition - substrate - growth
In this study, we present a new light absorption enhancement method for p-i-n thin film silicon solar cells using pyramidal surface structures, larger than the wavelength of visible light. Calculations show a maximum possible current enhancement of 45% compared with cells on a flat substrate. We deposited amorphous silicon (a-Si) thin film solar cells directly onto periodically pyramidal-structured polycarbonate (PC) substrates, which show a significant increase (30%) in short-circuit current over reference cells deposited on flat glass substrates. The current of the cells on our pyramidal structures on PC is only slightly lower than that of cells on Asahi U-type TCO glass (Asahi Glass Co., Tokyo, Japan), but suffer from a somewhat lower open circuit voltage and fill factor. Because the used substrates have a locally flat surface area due to the fabrication process, we believe that the current enhancement in the cells on structured PC can be increased using larger or more closely spaced pyramids, which can have a smaller flat surface area.
Verbetering spuittechniek in de teelt van potgrond : proof of principle toepassing Electrospray in de Glastuinbouw
Agostinho, L.L. ; Os, E.A. van; Riemersma, T. ; Nederlof, M. ; Staaij, M. van der - \ 2014
Wageningen : Wageningen UR Glastuinbouw (Rapport / Wageningen UR Glastuinbouw 1322) - 34
glastuinbouw - gewasbescherming - groeiremmers - methodologie - spuiten - bestrijdingsmethoden - depositie - proeven - druppelstudies - dosering - effecten - greenhouse horticulture - plant protection - growth inhibitors - methodology - spraying - control methods - deposition - trials - droplet studies - dosage - effects
ElectroHydroDynamische Atomisatie (EHDA) wordt ook wel “electrospraying” genoemd. Atomisatie is het proces van het uit elkaar vallen van een vloeistof in kleine druppeltjes. Een elektrisch veld wordt toegepast om het proces van druppelvorming (grootte van de druppels) te beïnvloeden en de druppeltjes een elektrisch lading mee te geven. De geladen druppeltjes stoten elkaar af waardoor een nevel ontstaat. Deze wordt aangetrokken door het gewas. Drie methoden van toepassen van gewasbeschermingsmiddelen zijn met elkaar vergeleken met behulp van een fluorescerende stof (Tinopal) op de bladeren van potplanten en chrysantenstek en bloemknoppen van roos: EHDA, conventioneel en een pulverisateur (rugketel). De verdeling van druppeltjes over de bladeren bij toepassing van EHDA is goed zowel bij de rozen als bij de potplanten en chrysantenstekken. Op de onderkant van de bladeren zijn echter geen druppletjes terecht gekomen. Dit heeft te maken met de grootte van de druppels, 200 micron. Deze zijn te zwaar om af te buigen naar de onderkant van de bladeren. Onderzoek in het verleden heeft aangetoond dat druppels met een kleinere diameter wel op de onderkant van de bladeren terecht komen. Bloemknoppen zijn opengemaakt om te kijken in hoeverre de druppeltjes in de knoppen zijn doorgedrongen. Bij toepassing van EHDA blijkt dit dieper te zijn dan bij de andere methoden.
Farm and management characteristics associated with boar taint
Wagenberg, C.P.A. van; Snoek, H.M. ; Fels, J.B. van der; Peet-Schwering, C.M.C. van der; Vermeer, H.M. ; Heres, L. - \ 2013
Animal 7 (2013)11. - ISSN 1751-7311 - p. 1841 - 1848.
entire male pigs - subcutaneous fat - skatole - androstenone - behavior - performance - deposition - economy - weight - system
Pig farms in the Netherlands producing boars have different levels of boar taint prevalence, as assessed by sensory evaluation with the human nose at the slaughter line. With a questionnaire to 152 Dutch pig producers (response rate 59%), farm and management characteristics were identified that are potentially associated with farm-level boar taint prevalence. Lower farm-level boar taint prevalence was associated with a smaller group size, a smaller pen surface per boar, newer housing equipment, not practicing restricted feeding in the last period before delivery, a longer fasting period before slaughter, a higher stocking weight and a lower fraction of boars from purebred dam line sows or from Pietrain terminal boars. These characteristics can be used to develop farm-level intervention strategies to control boar taint. More research effort is needed to establish causal relationships.
Differential Effects of Oxidised and Reduced Nitrogen on Vegetation and Soil Chemistry of Species-Rich Acidic Grasslands
Dorland, E. ; Stevens, C.J. ; Gaudnik, C. ; Corcket, E. ; Rotthier, S.L.F. ; Wotherspoon, K. ; Jokerud, M. ; Vandvik, V. ; Soons, M.B. ; Hefting, M.M. ; Aarrestad, P.A. ; Alard, D. ; Diekmann, M. ; Dupre, C. ; Dise, N.B. ; Gowing, D.J.G. ; Bobbink, R. - \ 2013
Water Air and Soil Pollution 224 (2013)9. - ISSN 0049-6979
biological nitrification inhibition - terrestrial ecosystems - seminatural grasslands - heathland vegetation - deposition - plant - acidification - biodiversity - diversity - eutrophication
Emissions and deposition of ammonia and nitrogen oxides have strongly increased since the 1950s. This has led to significant changes in the nitrogen (N) cycle, vegetation composition and plant diversity in many ecosystems of high conservation value in Europe. As a consequence of different regional pollution levels and of the increased importance of reduced N in the near future, determining the effect of different forms of N is an important task for understanding the consequences of atmospheric N inputs. We have initiated three replicated N addition experiments in species-rich, acidic grasslands spanning a climatic gradient in the Atlantic biogeographic region of Europe in Norway, Wales and France at sites with low levels of pollution. N was added in two doses (0 and 70 kg N ha(-1) year(-1) above background) and in three forms (oxidised N, reduced N and a 50-50 combination). After 2.5 years of N additions, the effects of these treatments on plant biomass, plant nutritional status, soil pH and soil nutrient availability were determined. Impacts of the N additions were observed within the 2.5-year research period. In some cases, the first signs of differential effects of N form could also be demonstrated. In the French site, for example, grass biomass was significantly increased by the oxidised N treatments but decreased by the reduced N treatments. In the Norwegian site, the reduced N treatments significantly reduced soil pH, whereas oxidised N did not. Effects on nutrient availability were also observed. These experiments will be continued to elucidate the longer term impacts of N deposition on these grasslands.
Hoe stikstof de vlinders laat stikken
Wallis de Vries, M.F. - \ 2013
Entomologische Berichten 73 (2013)4. - ISSN 0013-8827 - p. 158 - 163.
lepidoptera - habitats - depositie - stikstof - natuurgebieden - terrestrische ecologie - milieufactoren - deposition - nitrogen - natural areas - terrestrial ecology - environmental factors
De verstoring van de stikstofkringloop door de mens, via de productie van kunstmest en via industrie en verkeer, wordt als één van de grootste bedreigingen beschouwd voor de ecologische stabiliteit van de aarde. De atmosferische depositie van stikstof dringt tot ver in de natuurgebieden door. De effecten op de biodiversiteit zijn voor planten al goed onderzocht, maar de doorwerking op de dierenwereld is nog goeddeels onbekend. Dit artikel belicht de invloed op dagvlinders. De meeste soorten daarvan komen in stikstofarme milieus voor. Bij deze groep overheerst de neerwaartse trend, in tegenstelling tot soorten van stikstofrijkere milieus. Ook de afname in aantallen vlinders blijkt sterker te zijn met toenemende stikstofdepositie. Drie mechanismen lijken daarbij een rol te spelen: afname van voedselplanten, afname van voedselkwaliteit en afkoeling van het microklimaat in het voorjaar.
Electrospraying of water in oil emulsions for thin film coating
Khan, M.K.I. ; Maan, A.A. ; Schutyser, M.A.I. ; Schroën, C.G.P.H. ; Boom, R.M. - \ 2013
Journal of Food Engineering 119 (2013)4. - ISSN 0260-8774 - p. 776 - 780.
barrier properties - protein - atomization - deposition
Electrospraying of water-in-oil emulsions was investigated to produce thin edible barriers. A reproducible model surface was used, namely cellulose membranes of which permeability is well-established. PGPR-based emulsions were stable during electrospraying and produced a fine stable jet spray; emulsions prepared with lecithin and span80 produced unstable jets and only sporadic sprays. The droplet size decreased to 50 ± 10 µm by the addition of water droplets till 3% but remained constant at higher water volume fractions. On the other hand, the addition of protein and salt influenced the droplet size and radius values up to 200 µm were found. The addition of whey protein isolate (10% w/w) resulted in films with water vapour barrier properties that were at least 70% better than lipid only, therewith showing that addition of protein enhances the integrity of the films.
Assessing planetary and regional nitrogen boundaries related to food security and adverse environmental impacts
Vries, W. de; Kros, J. ; Kroeze, C. ; Seitzinger, S.P. - \ 2013
Current Opinion in Environmental Sustainability 5 (2013)3-4. - ISSN 1877-3435 - p. 392 - 402.
critical loads - climate-change - forest ecosystems - reactive nitrogen - global assessment - european forests - deposition - nutrient - world - consequences
This paper first describes the concept of, governance interest in, and criticism on planetary boundaries, specifically with respect to the nitrogen (N) cycle. These criticisms are then systematically evaluated. We argue that planetary N boundaries should include both the benefits and adverse impacts of reactive N (Nr) and the spatial variability of Nr impacts. We revise the planetary N boundary by considering the need to: first, avoid adverse impacts of elevated Nr emissions to water, air and soils, and second, feed the world population in an adequate way. The derivation of a planetary N boundary, in terms of anthropogenic fixation of di-nitrogen (N2) is illustrated by first, identification of multiple threat N indicators and setting limits for them; second, back calculating N losses from critical limits for N indicators, while accounting for the spatial variability of these indicators and their exceedance; and third, back calculating N fixation rates from critical N losses. The derivation of the needed planetary N fixation is assessed from the global population, the recommended dietary N consumption per capita and the N use efficiency in the complete chain from N fixation to N consumption. The example applications show that the previously suggested planetary N boundary of 35 Tg N yr-1 is too low in view of needed N fixation and also unnecessary low in view of most environmental impacts.
Nitrogen Addition and Warming Independently Influence the Belowground Micro-Food Web in a Temperate Steppe
Li, Q. ; Bai, H. ; Liang, W. ; Xia, J. ; Wan, S. ; Putten, W.H. van der - \ 2013
PLoS ONE 8 (2013)3. - ISSN 1932-6203
climate-change manipulations - species composition - community structure - plant-communities - organic-matter - northern china - soil nematodes - global change - elevated co2 - deposition
Climate warming and atmospheric nitrogen (N) deposition are known to influence ecosystem structure and functioning. However, our understanding of the interactive effect of these global changes on ecosystem functioning is relatively limited, especially when it concerns the responses of soils and soil organisms. We conducted a field experiment to study the interactive effects of warming and N addition on soil food web. The experiment was established in 2006 in a temperate steppe in northern China. After three to four years (2009–2010), we found that N addition positively affected microbial biomass and negatively influenced trophic group and ecological indices of soil nematodes. However, the warming effects were less obvious, only fungal PLFA showed a decreasing trend under warming. Interestingly, the influence of N addition did not depend on warming. Structural equation modeling analysis suggested that the direct pathway between N addition and soil food web components were more important than the indirect connections through alterations in soil abiotic characters or plant growth. Nitrogen enrichment also affected the soil nematode community indirectly through changes in soil pH and PLFA. We conclude that experimental warming influenced soil food web components of the temperate steppe less than N addition, and there was little influence of warming on N addition effects under these experimental conditions.
Kosten en baten van terrestrische natuur: methoden en resultaten : achtergronddocument bij Natuurverkenning 2010-2040
Leneman, H. ; Verburg, R.W. ; Heide, C.M. van der; Schouten, A.D. - \ 2013
Wageningen : Wettelijke Onderzoekstaken Natuur & Milieu (WOt-werkdocument 278) - 76
natuurbeheer - natuurgebieden - milieubeleid - depositie - kosten-batenanalyse - verdroging - koolstofvastlegging - biomassa productie - nature management - natural areas - environmental policy - deposition - cost benefit analysis - desiccation - carbon sequestration - biomass production
Dit werkdocument gaat in op de methoden en resultaten van de kosten en baten uit de atuurverkenning 2010- 2040, die met terrestrische natuur samenhangen. De kosten- en batenberekeningen worden getoond voor de vier kijkrichtingen uit de Natuurverkenning. De kostenberekeningen omvatten aankoop en inrichting, beheer en maatregelen om de verdroging en de depositie tegen te gaan. De effecten op houtproductie, biomassaproductie en koolstofvastlegging vormen de batenberekeningen. Ook zijn de secundaire kosten en baten van de kijkrichtingen voor de land- en tuinbouw geschat.
Separation process for very concentrated emulsions and suspensions in the food industry
Dinther, A.M.C. van; Schroën, C.G.P.H. ; Boom, R.M. - \ 2013
Innovative Food Science and Emerging Technologies 18 (2013). - ISSN 1466-8564 - p. 177 - 182.
induced particle migration - cross-flow microfiltration - shear-induced diffusion - flux decline - couette-flow - ultrafiltration - filtration - deposition
Separation of concentrated food suspensions and emulsions by e.g. microfiltration is currently not possible and therefore preceded by dilution, wasting energy and water. A new approach is shown, with sieves having pores much larger than the micron-sized droplets, low cross-flow velocities and a non-porous channel before the sieve. The complex behavior of concentrated emulsions under laminar flow in a non-porous channel causes depletion of large droplets and higher concentrations of small droplets near the wall. When the liquid flow through the pores relative to the channel flow is below a certain value, the liquid from the pores is completely devoid of larger droplets and has higher concentrations of small droplets than in the channel. This effect was caused by a combination of shear-induced migration in the channel and the interaction of droplets with the pores. Industrial separation processes can operate at high concentrations under mild conditions, potentially saving water and energy. Industrial relevance: Separation of suspensions, essential in processing any harvested agricultural material, is usually done by membrane separation or centrifugation, which is based on size exclusion by a membrane or a difference in density between particles and fluid, and this places intrinsic boundaries on the concentrations that can be processed, typically b5%. The sieve filtration process for micron-sized particles introduced here operates best at very high volume fractions and much lower cross-flow velocities than currently used. Industrial application of our finding could therefore have major benefits: no water is needed for dilution and waste is minimized. Besides energy used for dehydration and the separation process is reduced.
Efficiency of agricultural measures to reduce nitrogen deposition in Natura 2000 sites
Kros, J. ; Gies, T.J.A. ; Voogd, J.C.H. ; Vries, W. de - \ 2013
Environmental Science & Policy 32 (2013). - ISSN 1462-9011 - p. 68 - 79.
stikstof - depositie - ammoniak - emissiereductie - landbouw - natura 2000 - overijssel - nitrogen - deposition - ammonia - emission reduction - agriculture - atmospheric ammonia - netherlands - woodland - farms
This paper quantifies the efficiency of emission control measures in agriculture at landscape scale on the N deposition and critical N load exceedances in Natura 2000 sites. The model INITIATOR2 was run with spatially explicit farm data to predict atmospheric emissions of ammonia. These emissions were input of an atmospheric transport model to assess the N deposition in the Natura 2000 sites. Using the Dutch province of Overijssel as a case study, calculations for the year 2006 show that only 35% of the N deposition in the Natura 2000 sites were caused by agricultural NH3 emissions within the province. Comparatively most cost-efficient measures were low-emission application, followed by measures to reduce the protein content in feed. Relocating farms out of the Natura 2000 sites was very cost inefficient. Since critical N depositions of the Natura 2000 sites in Overijssel are largely exceeded in more than 90% of the area, the evaluated abatement measures were, however, not effective to reduce the area exceeding critical loads when only applied within the province Overijssel. Reductions of N deposition to a level below critical loads can only be achieved with the support of national and international emission reductions.
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