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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Boi-energy retains it's mitigration potential under elevated CO2
Liberloo, M. ; Luyssaert, S. ; Hoosbeek, M.R. - \ 2010
PLoS ONE 5 (2010)7. - ISSN 1932-6203 - 11 p.
rotation poplar plantation - carbon sequestration - coniferous forests - biomass production - greenhouse gases - enrichment - biofuels - soil - productivity - increases
Background - If biofuels are to be a viable substitute for fossil fuels, it is essential that they retain their potential to mitigate climate change under future atmospheric conditions. Elevated atmospheric CO2 concentration [CO2] stimulates plant biomass production; however, the beneficial effects of increased production may be offset by higher energy costs in crop management. Methodology/Main Findings - We maintained full size poplar short rotation coppice (SRC) systems under both current ambient and future elevated [CO2] (550 ppm) and estimated their net energy and greenhouse gas balance. We show that a poplar SRC system is energy efficient and produces more energy than required for coppice management. Even more, elevated [CO2] will increase the net energy production and greenhouse gas balance of a SRC system with 18%. Managing the trees in shorter rotation cycles (i.e., 2 year cycles instead of 3 year cycles) will further enhance the benefits from elevated [CO2] on both the net energy and greenhouse gas balance. Conclusions/Significance - Adapting coppice management to the future atmospheric [CO2] is necessary to fully benefit from the climate mitigation potential of bio-energy systems. Further, a future increase in potential biomass production due to elevated [CO2] outweighs the increased production costs resulting in a northward extension of the area where SRC is greenhouse gas neutral. Currently, the main part of the European terrestrial carbon sink is found in forest biomass and attributed to harvesting less than the annual growth in wood. Because SRC is intensively managed, with a higher turnover in wood production than conventional forest, northward expansion of SRC is likely to erode the European terrestrial carbon sink
Rope test may indicate efficacy of tail-biting treatments in growing pigs
Bracke, M.B.M. - \ 2009
Animal Welfare 18 (2009)3. - ISSN 0962-7286 - p. 263 - 266.
attraction - blood - enrichment - models
Tail biting is a most serious welfare problem in pigs raised for slaughter. In instances of an outbreak of tail biting, scientists have recommended that farmers take measures such as removal of affected animals, provision of enrichment materials and application of repellents to the pigs' tails. However, no scientific study has ever confirmed the efficacy of any of these suggestions in counteracting an ongoing outbreak. Here, the efficacy of two repellent ointments, Dippel's oil and Stockholm tar, were examined in a tail-chew test. For this, a novel piece of nylon rope was used as a tail model to measure biting behaviour semi-automatically in 24 single-sex groups of growing pigs (total 264 pigs). Repeated measures analysis showed no effect of time, gender or unit (12 pens per unit), but a highly significant effect of treatment, in that both Stockholm tar and Dippel's oil significantly reduced rope manipulation compared to controls. These results suggest that Stockholm tar and Dippel's oil may be effective in reducing tail biting. The approach taken may be valuable in further testing of strategies to reduce tail biting and improving pig welfare
The impact of long-term elevated CO2 on C and N retention in stable SOM pools
Graaff, M.A. de; Kessel, C. van; Six, J. - \ 2008
Plant and Soil 303 (2008)1-feb. - ISSN 0032-079X - p. 311 - 321.
trifolium-repens l - atmospheric co2 - carbon-dioxide - nitrogen mineralization - soil - grassland - enrichment - responses - ecosystem - dynamics
Elevated atmospheric CO2 frequently increases plant production and concomitant soil C inputs, which may cause additional soil C sequestration. However, whether the increase in plant production and additional soil C sequestration under elevated CO2 can be sustained in the long-term is unclear. One approach to study C-N interactions under elevated CO2 is provided by a theoretical framework that centers on the concept of progressive nitrogen limitation (PNL). The PNL concept hinges on the idea that N becomes less available with time under elevated CO2. One possible mechanism underlying this reduction in N availability is that N is retained in long-lived soil organic matter (SOM), thereby limiting plant production and the potential for soil C sequestration. The long-term nature of the PNL concept necessitates the testing of mechanisms in field experiments exposed to elevated CO2 over long periods of time. The impact of elevated CO2 and N-15 fertilization on L. perenne and T. repens monocultures has been studied in the Swiss FACE experiment for ten consecutive years. We applied a biological fractionation technique using long-term incubations with repetitive leaching to determine how elevated CO2 affects the accumulation of N and C into more stable SOM pools. Elevated CO2 significantly stimulated retention of fertilizer-N in the stable pools of the soils covered with L. perenne receiving low and high N fertilization rates by 18 and 22%, respectively, and by 45% in the soils covered by T. repens receiving the low N fertilization rate. However, elevated CO2 did not significantly increase stable soil C formation. The increase in N retention under elevated CO2 provides direct evidence that elevated CO2 increases stable N formation as proposed by the PNL concept. In the Swiss FACE experiment, however, plant production increased under elevated CO2, indicating that the additional N supply through fertilization prohibited PNL for plant production at this site. Therefore, it remains unresolved why elevated CO2 did not increase labile and stable C accumulation in these systems.
Microbial enrichment of torrefied grass fibers : a novel ingredient of potting soil
Trifonova, R.D. - \ 2008
University of Groningen. Promotor(en): J.D. van Elsas, co-promotor(en): Joeke Postma. - [S.l.] : S.n. - ISBN 9789036736695 - 146
groeimedia - vezels - hooi - grassen - microbiële flora - verrijking - verbeteraars - fytotoxiciteit - growing media - fibres - hay - grasses - microbial flora - enrichment - amendments - phytotoxicity
Transcriptome and proteonome profiling of colon mucosa from quercetin fed F344 rats point to tumor preventive mechanisms, increased mitochondrial fatty acid degradation and decreased glycolysis
Dihal, A.A. ; Hendriksen, P.J.M. ; Charif, H. ; Dekker, L.J. ; IJsselstijn, L. ; Boer, V.C.J. de; Alink, G.M. ; Rietjens, I.M.C.M. ; Woutersen, R.A. ; Stierum, R.H. - \ 2008
Proteomics 8 (2008)1. - ISSN 1615-9853 - p. 45 - 61.
gene-expression - colorectal-cancer - suppresses growth - messenger-rna - cell-line - identification - antioxidant - enrichment - pathway - targets
Quercetin has been shown to act as an anticarcinogen in experimental colorectal cancer (CRC). The aim of the present study was to characterize transcriptome and proteome changes occurring in the distal colon mucosa of rats supplemented with 10 g quercetin/kg diet for 11 wk. Transcriptome data analyzed with Gene Set Enrichment Analysis showed that quercetin significantly downregulated the potentially oncogenic mitogen-activated protein kinase (Mapk) pathway. In addition, quercetin enhanced expression of tumor suppressor genes, including Pten, Tp53, and Msh2, and of cell cycle inhibitors, including Mutyh. Furthermore, dietary quercetin enhanced genes involved in phase I and II metabolism, including Fmo5, Ephx1, Ephx2, and Gpx2. Quercetin increased PPAR target genes, and concomitantly enhanced expression of genes involved in mitochondrial fatty acid (FA) degradation. Proteomics performed in the same samples revealed 33 affected proteins, of which four glycolysis enzymes and three heat shock proteins were decreased. A proteome-transcriptome comparison showed a low correlation, but both pointed out toward altered energy metabolism. In conclusion, transcriptomics combined with proteomics showed that dietary quercetin evoked changes contrary to those found in colorectal carcinogenesis. These tumor-protective mechanisms were associated with a shift in energy production pathways, pointing at decreased cytoplasmic glycolysis and toward increased mitochondrial FA degradation.
Combined carbon and hydrogen isotope fractionation investigations for elucidating benzene biodegradation pathways
Fischer, A. ; Herklotz, I. ; Herrmann, S. ; Thullner, M. ; Weelink, S.A.B. ; Stams, A.J.M. ; Richnow, H.H. ; Vogt, C. - \ 2008
Environmental Science and Technology 42 (2008)12. - ISSN 0013-936X - p. 4356 - 4363.
aromatic hydroxylation - anaerobic biodegradation - toluene 4-monooxygenase - aerobic biodegradation - pseudomonas-putida - stable carbon - degradation - transformation - enrichment - mechanism
Recently, combined carbon and hydrogen isotope fractionation investigations have emerged as a powerful tool for the characterization of reaction mechanisms relevant for the removal of organic pollutants. Here, we applied this approach in order to differentiate benzene biodegradation pathways under oxic and anoxic conditions in laboratory experiments. Carbon and hydrogen isotope fractionation of benzene was studied with four different aerobic strains using a monooxygenase or a dioxygenase for the initial benzene attack, a facultative anaerobic chlorate-reducing strain as well as a sulfate-reducing mixed culture. Carbon and hydrogen enrichment factors (epsilon(C), epsilon(H)) varied for the specific pathways and degradation conditions, respectively, so that from the individual enrichment factors only limited information could be obtained for the identification of benzene biodegradation pathways. However, using the slope derived from hydrogen vs carbon isotope discriminations or the ratio of hydrogen to carbon enrichment factors (lambda = deltaH/ deltaC approximately epsilon(H)/epsilon(C)), benzene degradation mechanisms could be distinguished. Although experimentally determined lambda values partially overlapped, ranges could be determined for different benzene biodegradation pathways. Specific lambda values were <2 for dihydroxylation, between 7 and 9 for monohydroxylation, and > 17 for anaerobic degradation. Moreover, variations in lambda values suggest that more than one reaction mechanism exists for monohydroxylation as well as for anaerobic benzene degradation under nitrate-reducing, sulfate-reducing, or methanogenic conditions. Our results show that the combined carbon and hydrogen isotope fractionation approach has potential to elucidate biodegradation pathways of pollutants in field and laboratory microcosm studies
Interactions between plant growth and soil nutrient cycling under elevated CO2: a meta-analysis
Graaff, M.A. de; Groenigen, K.J. van; Six, J. ; Hungate, B. ; Kessel, C. van - \ 2006
Global Change Biology 12 (2006)11. - ISSN 1354-1013 - p. 2077 - 2091.
atmospheric carbon-dioxide - nitrogen-fixation - organic-matter - microbial biomass - tallgrass prairie - responses - enrichment - dynamics - forest - respiration
free air carbon dioxide enrichment (FACE) and open top chamber (OTC) studies are valuable tools for evaluating the impact of elevated atmospheric CO2 on nutrient cycling in terrestrial ecosystems. Using meta-analytic techniques, we summarized the results of 117 studies on plant biomass production, soil organic matter dynamics and biological N-2 fixation in FACE and OTC experiments. The objective of the analysis was to determine whether elevated CO2 alters nutrient cycling between plants and soil and if so, what the implications are for soil carbon (C) sequestration. Elevated CO2 stimulated gross N immobilization by 22%, whereas gross and net N mineralization rates remained unaffected. In addition, the soil C : N ratio and microbial N contents increased under elevated CO2 by 3.8% and 5.8%, respectively. Microbial C contents and soil respiration increased by 7.1% and 17.7%, respectively. Despite the stimulation of microbial activity, soil C input still caused soil C contents to increase by 1.2% yr(-1). Namely, elevated CO2 stimulated overall above- and belowground plant biomass by 21.5% and 28.3%, respectively, thereby outweighing the increase in CO2 respiration. In addition, when comparing experiments under both low and high N availability, soil C contents (+2.2% yr(-1)) and above- and belowground plant growth (+20.1% and+33.7%) only increased under elevated CO2 in experiments receiving the high N treatments. Under low N availability, above- and belowground plant growth increased by only 8.8% and 14.6%, and soil C contents did not increase. Nitrogen fixation was stimulated by elevated CO2 only when additional nutrients were supplied. These results suggest that the main driver of soil C sequestration is soil C input through plant growth, which is strongly controlled by nutrient availability. In unfertilized ecosystems, microbial N immobilization enhances acclimation of plant growth to elevated CO2 in the long-term. Therefore, increased soil C input and soil C sequestration under elevated CO2 can only be sustained in the long-term when additional nutrients are supplied.
Roles of metal ion complexation and membrane permeability in the metal flux through lipophilic membranes. Labile complexes at permeation liquid membranes
Zhang, Z. ; Buffle, J. ; Leeuwen, H.P. van; Wojciechowski, K. - \ 2006
Analytical Chemistry 78 (2006)16. - ISSN 0003-2700 - p. 5693 - 5703.
copper speciation - natural-waters - trace-metals - fatty-acid - separation - voltammetry - system - enrichment - transport - as(iii)
The various physicochemical factors that influence the flux of carrier-transported metal ions through permeation liquid membranes (PLM) are studied systematically. Understanding PLM behavior is important (i) to optimize the application of PLM as metal speciation sensors in environmental media and (ii) because PLM may serve as bioanalogical devices that help to elucidate the environmental physicochemical processes occurring at the surface of biological membranes. Diffusion of free and complexed metal ions in solution, as well as diffusion of the metal carrier complex in the membrane, is considered. The respective roles of diffusion layer thickness, ligand concentration, complex stability, carrier concentration, and membrane thickness are studied experimentally in detail and compared with theory, using various labile complexes, namely, Pb(II)-diglycolate, Cu(II)-diglycolate, and Cu(II)-N-(2-carboxyphenyl)glycine. Conditions where either membrane diffusion or solution diffusion is rate limiting are clearly discriminated. It is shown in particular, that, by tuning the carrier concentration or membrane thickness, either the free metal ion concentration or the total labile metal species are measured. PLM can thus be used to determine whether models based on the free ion activity in solution (such as BLM or FIAM models) are applicable to metal uptake by microorganisms in a real natural medium
Effects of rearing and housing environment on behaviour and performance of pigs with different coping characteristics
Bolhuis, J.E. ; Schouten, W.G.P. ; Schrama, J.W. ; Wiegant, V.M. - \ 2006
Applied Animal Behaviour Science 101 (2006)1-2. - ISSN 0168-1591 - p. 68 - 85.
growing pigs - disintegration method - agonistic behavior - weaned pigs - pen size - enrichment - welfare - straw - productivity - provision
The availability of a rooting substrate may profoundly affect behaviour and welfare of pigs. Apart from their actual housing environment, also the conditions present in early life and individual characteristics may influence the behaviour of pigs. The present study investigated the relative importance of the housing environment during rearing and the actual housing environment on behaviour during the finishing phase, pathological lesions of the heart and stomach wall and weight gain in pigs with diverging coping characteristics. Pigs were reared either without a rooting substrate (barren, B) or in identical pens enriched with straw bedding (enriched, E). During the suckling period piglets were subjected to the Backtest. The Backtest classification of pigs is, to a certain extent, predictive of their coping style. Each piglet was restrained in supine position for 1 min and its resistance (i.e. the number of escape attempts) was scored. Sixty high-resisting (HR) and 60 low-resisting (LR) pigs were selected. Half of these pigs were from barren and the other half from enriched rearing environments. Pigs were housed in groups of six (three HR and three LR) after weaning. At 10 weeks of age, environmental conditions (B or E) were switched for half of the pens. Behaviour patterns of pigs during the finishing phase were largely determined by the actual presence or absence of straw bedding. Pigs that changed from enriched to barren pens (EB pigs), however, showed an increased inactivity beyond the inactivity levels of pigs with a barren rearing history (BB pigs). The impact of rearing history on chewing, manipulative and play behaviour in later life was larger for LR than for HR pigs. The availability of straw reduced the occurrence of gastric lesions in LR, but not in HR pigs. Feed intake tended to be lower in EB pens than in EE pens, but this was reflected in the growth rate of HR pigs only. HR-EE pigs showed a higher weight gain than HR-EB pigs. In conclusion, behaviour patterns of pigs were largely influenced by the actual (in)availability of straw. The influence of rearing history on behaviour, occurrence of gastric lesions and weight gain was smaller, and depended to some extent on coping characteristics (LR or HR) of the pigs under study
Mycorrhizal hyphal turnover as a dominant process for carbon input into soil organic matter
Godbold, D. ; Hoosbeek, M.R. ; Lukac, M. ; Francesca Cotrufo, M. ; Janssens, I.A. ; Ceulemans, R. ; Polle, A. ; Velthorst, E.J. ; Scarascia-Mugnozza, G. ; Angelis, P. de; Miglietta, F. ; Peressotti, A. - \ 2006
Plant and Soil 281 (2006)1-2. - ISSN 0032-079X - p. 15 - 24.
elevated atmospheric co2 - douglas-fir ecosystem - 1st growing-season - ectomycorrhizal fungi - forest ecosystems - external mycelium - root turnover - enrichment - nitrogen - patterns
The atmospheric concentration of CO2 is predicted to reach double current levels by 2075. Detritus from aboveground and belowground plant parts constitutes the primary source of C for soil organic matter (SOM), and accumulation of SOM in forests may provide a significant mechanism to mitigate increasing atmospheric CO2 concentrations. In a poplar (three species) plantation exposed to ambient (380 ppm) and elevated (580 ppm) atmospheric CO2 concentrations using a Free Air Carbon Dioxide Enrichment (FACE) system, the relative importance of leaf litter decomposition, fine root and fungal turnover for C incorporation into SOM was investigated. A technique using cores of soil in which a C-4 crop has been grown (delta C-13 -18.1 parts per thousand) inserted into the plantation and detritus from C-3 trees (delta C-13 -27 to -30 parts per thousand) was used to distinguish between old (native soil) and new (tree derived) soil C. In-growth cores using a fine mesh (39 mu m) to prevent in-growth of roots, but allow in-growth of fungal hyphae were used to assess contribution of fine roots and the mycorrhizal external mycelium to soil C during a period of three growing seasons (1999-2001). Across all species and treatments, the mycorrhizal external mycelium was the dominant pathway (62%) through which carbon entered the SOM pool, exceeding the input via leaf litter and fine root turnover. The input via the mycorrhizal external mycelium was not influenced by elevated CO2, but elevated atmospheric CO2 enhanced soil C inputs via fine root turnover. The turnover of the mycorrhizal external mycelium may be a fundamental mechanism for the transfer of root-derived C to SOM.
Long-term effects of elevated atmospheric CO2 on species composition and productivity of a southern African C4 dominated grassland in the vicinity of a CO2 exhalation.
Stock, W.D. ; Ludwig, F. ; Morrow, C. ; Midgley, G.F. ; Wand, S.J.E. ; Allsopp, N. ; Bell, T.L. - \ 2005
Plant Ecology 178 (2005)2. - ISSN 1385-0237 - p. 211 - 224.
tallgrass prairie ecosystem - soil carbon - biomass production - plant-communities - water relations - gas-exchange - growth - enrichment - responses - dynamics
We describe the long-term effects of a CO2 exhalation, created more than 70 years ago, on a natural C4 dominated sub-tropical grassland in terms of ecosystem structure and functioning. We tested whether long-term CO2 enrichment changes the competitive balance between plants with C3 and C4 photosynthetic pathways and how CO2 enrichment has affected species composition, plant growth responses, leaf properties and soil nutrient, carbon and water dynamics. Long-term effects of elevated CO2 on plant community composition and system processes in this sub-tropical grassland indicate very subtle changes in ecosystem functioning and no changes in species composition and dominance which could be ascribed to elevated CO2 alone. Species compositional data and soil ¿13C isotopic evidence suggest no detectable effect of CO2 enrichment on C3:C4 plant mixtures and individual species dominance. Contrary to many general predictions C3 grasses did not become more abundant and C3 shrubs and trees did not invade the site. No season length stimulation of plant growth was found even after 5 years of exposure to CO2 concentrations averaging 610 ¿mol mol-1. Leaf properties such as total N decreased in the C 3 but not C4 grass under elevated CO2 while total non-structural carbohydrate accumulation was not affected. Elevated CO2 possibly lead to increased end-of-season soil water contents and this result agrees with earlier studies despite the topographic water gradient being a confounding problem at our research site. Long-term CO2 enrichment also had little effect on soil carbon storage with no detectable changes in soil organic matter found. There were indications that potential soil respiration and N mineralization rates could be higher in soils close to the CO2 source. The conservative response of this grassland suggests that many of the reported effects of elevated CO2 on similar ecosystems could be short duration experimental artefacts that disappear under long-term elevated CO2 conditions
Effecten van brand op bodem en vegetatie in dennenbossen van voedselarme zandgronden bij Kootwijk
Kemmers, R.H. ; Dirkse, G.M. ; Hille, M.G. ; Mekkink, P. - \ 2005
Wageningen : Alterra (Alterra-rapport 1028) - 57
naaldbossen - bossen - verbranden - bodem - vegetatie - zandgronden - bosbranden - stikstof - verrijking - natuurgebieden - veluwe - gelderland - coniferous forests - forests - burning - soil - vegetation - sandy soils - forest fires - nitrogen - enrichment - natural areas
Door atmosferische stikstofdepositie zijn veel bossen van de arme zandgronden vermest en in hun verdere successie verstoord. In een voedselarm dennenbos op zandgrond is onderzocht of door brand de overmaat aan stikstof die in de strooisellaag ligt opgeslagen kan worden teruggedrongen en de bosontwikkeling kan worden teruggezet naar een voedselarme pionierfase. Het onderzoek werd uitgevoerd bij Kootwijk waar in 1995 een bosbrand woedde. De vegetatie- en bodemkundige toestand van voor de brand, één en negen jaar na de brand werd geanalyseerd. Een belangrijke conclusie is dat brand eerder tot een verrijking van de bodem leidt dan tot een verschraling. Door brand vindt een verplaatsing van elementen van ectorganische naar endorganische horizonten plaats. Weliswaar verdwijnt er in zijn totaliteit stikstof, maar direct na de brand is de bodem sterk verrijkt met kalium, ammonium en fosfaat en in zuurgraad gedaald. Bovendien wordt het beschikbaar gekomen ammonium door micro-organismen vastgelegd in organische stof wat daardoor een rijk karakter krijgt. Dit effect is negen jaar na de brand nog steeds aanwezig. Het laten staan van de necromassa na de brand, zoals in Kootwijk plaatsvond, draagt niet bij aan het terugzetten van de vegetatiesuccessie naar een initieel schraal stadium, maar wel aan de diversiteit van bodemeigenschappen
Personalities in pigs: Individual characteristics and coping with environmental challenges
Bolhuis, J.E. - \ 2004
Wageningen University. Promotor(en): V.M. Wiegant, co-promotor(en): W.G.P. Schouten; Johan Schrama. - [S.l.] : S.n. - ISBN 9085040620 - 176
varkens - persoonlijkheid - karakterisering - individuele kenmerken - stress - stressreactie - varkensstallen - adaptatie - diergedrag - dierenwelzijn - milieu - verrijking - immuniteitsreactie - dierfysiologie - pigs - personality - characterization - individual characteristics - stress response - pig housing - adaptation - animal behaviour - animal welfare - environment - enrichment - immune response - animal physiology
There are indications that pigs may have difficulty in adapting to the constraints of intensive housing conditions. Pigs show a wide variation in adaptive responses when exposed to the same stressful situation. Aim of this thesis was to investigate whether the behavioural coping responses of young piglets reflect and predict more general profiles of reactivity to challenges, often referred to as coping styles, under different rearing and housing conditions. For this purpose, pigs were characterized early in life as `high-resisting` (HR) or `low-resisting` (LR) on the basis of their resistance response in a so-called Backtest, in which they were manually restrained in supine position. The major part of the thesis focused on the interaction between these individual coping characteristics of pigs and their housing environment, which was either barren or enriched with straw bedding. The experiments described in this thesis show that HR pigs are more aggressive than LR pigs and less flexible in adapting their behaviour to environmental changes. As the two types of pig differed in response to the dopamine-agonist apomorphine, some initial evidence is provided for a neurochemical background of these behavioural differences. In addition, individual coping or personality characteristics of pigs were reflected in immune reactivity and in their home pen behaviour in barren and enriched environments. HR and LR pigs adapted differently to barren housing conditions. Moreover, individual characteristics modulated the effects of rearing and housing conditions on the behavioural response to novelty, immune reactivity, prevalence of gastric lesions and behavioural development. Remarkably, for almost all of the variables that were affected by housing environment, the impact was much larger for LR than for HR pigs. Thus, individual characteristics of pigs affect their performance in different environments and should be taken into account when studying the impact of housing on their behaviour and welfare. The knowledge of individual coping or personality characteristics could be extended and used for finding the optimal match between pigs and their social and physical environment in pig husbandry.
Nutrient limitation and nutrient-driven shifts in plant species composition in a species-rich fen meadow
Hoek, D. van der; Mierlo, A.J.E.M. van; Groenendael, J.M. van - \ 2004
Journal of Vegetation Science 15 (2004). - ISSN 1100-9233 - p. 389 - 396.
soortendiversiteit - plantenecologie - biomassa - inundatie - eutrofiëring - veengronden - stikstof - natuurreservaten - laagveengebieden - nederland - gelderland - species diversity - plant ecology - biomass - flooding - eutrophication - peat soils - nitrogen - nature reserves - fens - netherlands - mineral-nutrition - wild plants - vegetation - availability - enrichment - phosphorus - community - diversity - tundra
Question: We studied the development and persistence of the effects of nutrient pulses on biomass production and species composition in a fen meadow. Location: Nature reserve, central Netherlands, 5 m a.s.l. Methods: Single pulse fertilization with N and P in a factorial design on an undrained central and a drained margin site in a species-rich fen meadow (Cirsio dissecti-Molinietum). Biomass production and species composition were monitored during four years. Results: At the central site, N addition boosted biomass production, but only during one year. The species composition was not changed. P fertilization increased the biomass production and changed the species composition from a vegetation dominated by Carex panicea to a grassland community with abundant Holcus lanatus, but not before the second year. At the margin site, P fertilization changed the species composition in a similar way, but biomass production was not increased. N fertilization had no effect. At both sites the P induced shift in species composition persisted for four years although the P effect declined during the experiment. Conclusions: The biomass responses show that N was limiting in the central site. Another nutrient, besides N and P (probably K) must have been limiting in the marginal site. The fast decline of the N effect on biomass is ascribed to increased denitrification and biomass removal. The delay in the P effect on biomass and species composition and the persistence of the P effect on species composition are ascribed to fast immobilisation and subsequent slow release of fertilizer P in the peat soil. Recurrence of the P pulses is expected to cause permanent changes in species composition
Colony formation in Scenedesmus: a literature overview and further steps towards the chemical characterisation of the Daphnia kairomone
Holthoon, F.L. van; Beek, T.A. van; Lürling, M.F.L.L.W. ; Donk, E. van; Groot, Æ. de - \ 2003
Hydrobiologia 491 (2003)1-3. - ISSN 0018-8158 - p. 241 - 254.
diel vertical migration - morphological-changes - ecological role - fish - zooplankton - trimethylamine - induction - growth - enrichment - pheromone
Semiochemicals play an important role in interactions between living organisms in aquatic environments. Although the presence of chemical cues is confirmed in more and more systems, the chemical structures remain predominantly elusive. To create more accurate prey¿predator interaction models and to advance the research on chemical communication, it is essential to identify these compounds. A literature overview of cues involving Daphnia (either as producer or receiver) is given and the progress towards their isolation and structure elucidation is described. Most of the research so far has concentrated on the elucidation of kairomones produced by predators of Daphnia (especially Chaoborus and several species of fish). Although some progress has been made, these cues have not been isolated and identified yet. Additionally new results on the isolation and identification of the kairomone responsible for the colony formation in Scenedesmus using differential diagnosis and bioassay-directed fractionation of Daphnia exudates are presented. The importance of suitable and well performing bioassays herein cannot be underestimated. Some preliminary results with solid-phase extraction with C18 proved to be reproducible for extracting the active compound from Daphnia water, although it was not possible to get the biological activity into a single fraction. The cue was not extractable with an anion exchanger (SAX). Subjecting the extract to HPLC led to one active fraction
Verrijkte kooien voor leghennen in al zijn onderdelen
Fiks, T.G.C.M. ; Reuvekamp, B.F.J. ; Emous, R.A. van - \ 2003
Lelystad : Praktijkonderzoek Veehouderij (Praktijkboek / Animal Sciences Group 31) - 62
hennen - pluimveehouderij - pluimveehokken - kooien - verrijking - dierenwelzijn - hens - poultry farming - poultry housing - cages - enrichment - animal welfare
Het merendeel van de leghennen in de wereld wordt gehouden in batterijhuisvesting. Dit systeem heeft zich ontwikkeld vanuit een aantal wensen die aan de houderij van leghennen gesteld werd. Deze eisen lagen vooral op het gebied van economie, management, milieu, diergezondheid en productkwaliteit. Op deze punten scoort de legbatterij dan ook ruim voldoende. In de periode van de opkomst van de legbatterij als houderijsysteem was welzijn van dieren nog geen issue. Inmiddels wordt het welzijn van landbouwhuisdieren echter door diverse wetten en regels gewaarborgd. : :De in de EU-richtlijn van 1999 (EU, 1999a) genoemde verrijkte kooi werd ontwikkeld met het idee het goede van de batterij te behouden en de slechte kanten te verbeteren. In deze kooi zijn verschillende elementen ingebouwd, die het dier in staat stelt tot het vertonen van soortspecifiek gedrag. Hoewel de kostprijs van een ei uit de verrijkte kooi hoger is dan uit de batterij, biedt het systeem goede perspectieven met betrekking tot milieu, management, diergezondheid en productveiligheid. Voor het welzijn van het dier is het systeem een compromis tussen wat het dier verlangt en wat de pluimveehouder nodig heeft. In deze uitgave belichten we alle aspecten van verrijkte kooien, zowel vanuit de dierkant als vanuit de pluimveehouder. Het doel van deze uitgave is meerledig: : :1) Het geven van een samenvatting over al het verrichte onderzoek heen. : :2) Het op een toegankelijke wijze presenteren van alle aspecten, die van belang zijn bij verrijkte kooien. : :3) Het geven van tips waarop men moet letten bij de aanschaf en voor het management van verrijkte kooien.
Verrijkte kooien
Emous, R.A. van; Fiks, T.G.C.M. ; Reuvekamp, B.F.J. - \ 2003
Lelystad : Praktijkonderzoek Veehouderij (PraktijkRapport / Animal Sciences Group, Praktijkonderzoek : Pluimvee ) - 77
hennen - pluimveehokken - kooien - verrijking - snavelkappen - zitstokken (vogels) - legresultaten - verenpikken - kannibalisme - belichting - dierenwelzijn - hens - poultry housing - cages - enrichment - debeaking - perches - laying performance - feather pecking - cannibalism - illumination - animal welfare
Ruim 75 % van de leghennen in Nederland wordt in batterijkooien gehouden. Deze kooi werd vele jaren gezien als het ideale houderijsysteem voor leghennen. Vanuit ethologisch gezichtspunt is het houden van legkippen in batterijsystemen echter een flinke beperking voor de dieren. Om deze reden is de batterij in een kwaad daglicht komen te staan en is vanuit de maatschappij de roep om welzijnsvriendelijkere huisvestingssystemen steeds sterker geworden. Men houdt steeds meer leghennen in alternatieve systemen als scharrel en volière, waar de dieren de beschikking hebben over een ruime hoeveelheid strooisel. Verder zijn er legnesten en zitstokken in de systemen ingebouwd. Volière en scharrel zijn voor de kleinere bedrijven goede alternatieven. Voor grote bedrijven zijn ze minder aantrekkelijk, omdat ze minder voorspelbaar in arbeid zijn, storingsgevoeliger in productie, hogere milieubelasting (NH3 en stof) hebben en een hogere kostprijs van de eieren. Tot eind jaren 90 verliep de omschakeling naar dit soort systemen erg langzaam, maar nadat de EU-richtlijn voor het houden van leghennen in 1999 van kracht werd, is in Nederland veel geïnvesteerd in alternatieve systemen. De ontwikkelingen naar welzijnsvriendelijke houderij van leghennen is geen Nederlandse aangelegenheid. Dit bleek uit de wijziging in de Europese regelgeving, die in 1999 is doorgevoerd. Deze legt de huisvesting van leghennen in kooien aan banden en verbiedt het huidige batterijsysteem per 1 januari 2012. Vanaf die datum is alleen de huisvesting in alternatieven (scharrel/volière) of in verrijkte kooisystemen toegestaan. Het Nederlandse bedrijfsleven heeft de roep naar welzijnsvriendelijkere huisvestingssystemen voor leghennen onder anderen vertaald naar een opdracht voor het Praktijkonderzoek om de verrijkte kooisystemen te onderzoeken en te ontwikkelen. Als uitgangspunt voor de systemen gold dat ze gebaseerd moesten zijn op het kooiprincipe en minimaal moesten voldoen aan de eisen zoals die in de EU-richtlijn van juli 1999 zijn geformuleerd. Dit onderzoek heeft vorm gekregen in het Project Verrijkte kooien voor leghennen, ook wel kortweg bekend onder de naam Project 1030 (het aanvankelijke interne projectnummer). Gezien de korte termijn waarop bedrijfsleven en politiek informatie moesten hebben over verrijkte kooisystemen, is gekozen voor een proefopzet, waarbij veel verschillende systemen zijn getest. Het Ingrepenbesluit bepaalt dat in nieuwe houderijsystemen die men na 1 september 2001 in gebruik neemt geen dieren mogen worden opgezet die een snavelbehandeling hebben ondergaan. Voor alternatieve houderijsystemen is echter een uitstel van 5 jaar verleend. Dit geldt niet voor kooisystemen (dus ook verrijkte kooien), omdat de kleinere groepsgrootte verenpikkerij en kannibalisme daar beter beheersbaar maakt. Hoewel de groepen dieren in kooien kleiner zijn dan in alternatieve houderijsystemen moet men echter wel rekening houden met dit potentiële pikkerijprobleem. Dit gegeven was aanleiding om extra aandacht te besteden aan het houden van ongekapte hennen en het voorkómen van verenpikkerij en kannibalisme. Het toepassen van verschillende verlichtingssystemen is daarom onderwerp van onderzoek geweest. Het eerste en belangrijkste doel van het onderzoek aan verrijkte kooisystemen was het testen ervan en het opdoen van ervaringen met verschillende ontwerpen. Ook binnen elk kooisysteem zijn diverse varianten getest om te zien welke het beste functioneert. Daarbij is ervaring opgedaan die breder gaat dan alleen dat bewuste systeem, zodat ook algemenere conclusies mogelijk zijn. De hoofdvraag van het onderzoek was telkens: hoe functioneert een systeem. De punten waarnaar we keken zijn: Wat zijn de productieresultaten? Hoe is de eikwaliteit? Wat is de uitval en in het bijzonder de uitval door pikkerij? Hoe functioneren het legnest, de strooiselruimte, de zitstokken en het nagelgarnituur? Hoe gedragen de dieren zich: gebruiken ze het strooisel, het legnest en d
Effect van verrijking omgeving en beperking weidegang op wroetschade door zeugen
Mheen, H. van der; Spoolder, H.A.M. - \ 2003
Lelystad : Praktijkonderzoek Veehouderij (PraktijkRapport / Praktijkonderzoek Veehouderij : Varkens ) - 21
zeugen - varkenshouderij - rantsoenbeweiding - weiden - schade - verrijking - mineralen - stikstof - diergedrag - biologische landbouw - sows - pig farming - controlled grazing - pastures - damage - enrichment - minerals - nitrogen - animal behaviour - organic farming
Veel biologische varkenshouders weiden hun drachtige en guste zeugen. Het in stand houden van de graszode is door het wroeten van varkens echter niet vanzelfsprekend, maar wel gewenst. Zonder gras valt er weinig meer te grazen en valt het voordeel vanextra voeropname weg. Daarnaast is de uitspoeling van mineralen op kale grond veel groter dan op grasland.
Model simulation of effects of changes in climate and atmospheric CO2 and O3 on tuber yield potential of potato (cv Bintje) in the European Union
Wolf, J. ; Oijen, M. van - \ 2003
Agriculture, Ecosystems and Environment 94 (2003). - ISSN 0167-8809 - p. 141 - 157.
triticum-aestivum l - open-top chambers - elevated co2 - spring wheat - photosynthetic apparatus - ozone - growth - acclimation - enrichment - responses
A simple simulation model for potato growth was improved on the basis of the experimental results from the EU-project CHIP. To test if the model works well for the different CO2 and O3 treatments under a range of environmental conditions in the EU, the experimental results from all treatments at the sites within this project were compared with the simulated results. A detailed analysis was done first for Rapolano, Italy and Tervuren, Belgium. This showed that in general the time courses of the observed CO2 and O3 effects on tuber yields at Tervuren and of the CO2 effect at Rapolano were simulated well. Next, crop variables as observed at the final harvest in all experiments within this project were compared with the simulated results. This showed that the total radiation interception was simulated well. Radiation use efficiency (RUE), however, was simulated well for only half of the sites. As a consequence, total biomass and tuber yields could only be simulated well for all sites, if photosynthetic parameters in the model were calibrated separately for half of the sites. These and other difficulties in the development and testing of the potato model on the basis of the CHIP experimental data set were discussed.
Huisvesting en verzorging van vleeskuikenouderdieren zonder ingrepen
Haar, J.W. van der; Voorst, A. van; Middelkoop, J.H. van; Lourens, A. - \ 2002
Lelystad : Praktijkonderzoek Veehouderij (PraktijkRapport. Pluimvee 3) - 23
vleeskuikens - pluimveehokken - dierenwelzijn - milieu - verrijking - vleeskuikenouderdieren - broilers - poultry housing - animal welfare - environment - enrichment - broiler breeders
Door het Ingrepenbesluit zijn ingrepen bij vleeskuikenouderdieren op termijn verboden. Praktijkonderzoek Veehouderij (voorheen Praktijkonderzoek Pluimveehouderij) onderzoekt daarom sinds 1998 het effect van het achterwege laten van ingrepen bij vleeskuikenouderdieren in relatie tot huisvesting en verzorging. Dit rapport beschrijft de resultaten van de laatste (derde) proef. Al eerder verschenen de bevindingen over de effecten van weglaten van ingrepen bij vleeskuikenouderdieren op gedrag, veer- en huidbeschadigingen, uitval en technische resultaten.
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