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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Purifying manure effluents with duckweed
Timmerman, M. ; Hoving, I.E. - \ 2016
Wageningen UR Livestock Research (Livestock Research rapport 942) - 27 p.
animal manures - effluents - lemna - aquatic weeds - feeds - nutrients - ingredients - animal feeding - animal nutrition - waste water - biogas - biomass production - cultivation - biobased economy - dierlijke meststoffen - afvoerwater - schadelijke waterplanten - voer - voedingsstoffen - ingrediënten - diervoedering - diervoeding - afvalwater - biomassa productie - teelt
The objective of this study was to perform a short literature survey to provide information about purifying manure effluents with duckweed with regard to varieties, cultivation, harvesting methods, utilization and valorisation of duckweed. The results of the study show that duckweed can be used to recuperate nutrients from manure effluents and that the concerning duckweed can be utilized as a source of feed, energy and ingredients
Project Kleinschalige bioraffinage : Inventarisatie innovatieve digestaatverwerking in combinatie met teelt aquatische biomassa - Beschrijving teeltsystemen en monitoringsplan
Dijk, W. van; Hoeksma, P. ; Weide, R.Y. van der - \ 2014
Lelystad : PPO AGV (Deliverables D5.7) - 16
teeltsystemen - algenteelt - lemna - digestaat - mineralen - plantenvoeding - melkveehouderij - geïntegreerde bedrijfssystemen - voer - biomassa productie - biobased economy - aquatische biomassa - cropping systems - algae culture - digestate - minerals - plant nutrition - dairy farming - integrated farming systems - feeds - biomass production - aquatic biomass
Aquatische teelten (o.a. algen, eendenkroos) staan op dit moment volop in de belangstelling. Eén van de factoren voor een voldoende groei is de nutriëntenvoorziening. Uit oogpunt van duurzaamheid en het sluiten van kringlopen is er een voorkeur voor mest(producten) of afvalwater als nutriëntenbron. Naast technische beperkingen (o.a. troebelheid) zijn er ook wettelijke aspecten die de aandacht behoeven bij toepassing van deze nutriëntenbronnen. Dit betreft zowel de mestwetgeving als toelatingseisen voor gebruik als veevoer. Binnen het werkpakket aquatische biomassa van de TKI kleinschalige bioraffinage is nagegaan welke oplossingen mogelijk zijn en welke informatie hiervoor nodig is. Dit doen we aan de hand van twee lopende pilots: algenteelt bij bedrijf Kelstein en eendenkroosteelt bij bedrijf Algaecom. In dit rapport worden de productiesystemen en de monitoringsplannen beschreven.
Inkuilen van eendenkroos als veevoer met verschillende additieven = Ensiling Duckweed for feed with different additives
Hoving, I.E. ; Schooten, H.A. van; Holshof, G. ; Houwelingen, K.M. van; Geest, W. van de - \ 2011
Lelystad : Wageningen UR Livestock Research (Rapport / Wageningen UR Livestock Research 528) - 30
waterplanten - lemna - vochtgehalte - droging - kuilvoerbereiding - voedertoevoegingen - kuilvoerfermentatie - aquatic plants - moisture content - drieration - silage making - feed additives - silage fermentation
Ferment duckweed as silage is a cheap and sustainable alternative for drying. Without an additive, no satisfying preservation result was reached. Molasses gave a good preservation result and is relatively cheap and practical. Common methods of forage ensilaging are not suitable for duckweed as they have too little product structure to facilitate wrapping. The use of an airtight container or silo may lead to good preservation results, and prevent losses.
Eendekroos nu ook voor de koe
Holshof, G. - \ 2008
V-focus 5 (2008)3. - ISSN 1574-1575 - p. 30 - 33.
rundveehouderij - rundveevoeding - krachtvoeding - lemna - lemnaceae - plantaardig eiwit - vervangmiddelen - waterplanten - cattle husbandry - cattle feeding - force feeding - plant protein - substitutes - aquatic plants
Eendenkroos is geschikt als eiwitgrondstof voor krachtvoer en is bij de productie van mengvoer goed uitwisselbaar met gangbare grondstoffen als soja. Voor de veehouderij zijn vanwege de hoge prijzen alternatieve eiwitbronnen welkom; daarbij staat het gebruik van soja maatschappelijk ter discussie. In een pilot is kroos verwerkt tot 3 verschillende krachtvoerproducten. Oogsten van Spakenburg en Stolwijk zijn bemonsterd op zware metalen en voederwaarden. De eerste resultaten wijzen op een perspectiefvolle nieuwe grondstof voor veevoeders
Eendenkroos als veevoer : kijken met een ander oog naar kroos
Hoving, Idse - \ 2007
livestock farming - fodder - lemna - feed industry - fodder plants - applied research - dairy cattle nutrition
A simple equation for describing the temperature dependent growth of free-floating macrophytes
Heide, Tj. van; Roijackers, R.M.M. ; Nes, E.H. van; Peeters, E.T.H.M. - \ 2006
Aquatic Botany 84 (2006)2. - ISSN 0304-3770 - p. 171 - 175.
salvinia-molesta - water macrophytes - climate-change - azolla - responses - nitrogen - ditches - lemna - model
Temperature is one of the most important factors determining growth rates of free-floating macrophytes in the field. To analyse and predict temperature dependent growth rates of these pleustophytes, modelling may play an important role. Several equations have been published for describing temperature responses of macrophytes and algae. But they are often complex or are only applicable in a limited range of temperatures. In this paper, we present a simple three-parameter equation for describing the temperature dependent growth rates of pleustophytes. The equation that we developed is tested using results from laboratory growth experiments conducted with three different species of pleustophytes (Lemna minor, Salvinia molesta and Azolla filiculoides). The equation is simple and demonstrates reliable fits (adjusted R2 reaching from 0.89 to 0.95). Additionally, our equation primarily uses parameters of biological significance, resulting in estimates of useful cardinal temperatures (minimum and maximum)
Experiments with duckweed-moth systems suggest global warming may reduce rather than promote herbivory
Heide, Tj. van; Roijackers, R.M.M. ; Peeters, E.T.H.M. ; Nes, E.H. van - \ 2006
Freshwater Biology 51 (2006)1. - ISSN 0046-5070 - p. 110 - 116.
biological-control - south-africa - temperature - ditches - lemna
1. Wilf & Labandeira (1999)suggested that increased temperatures because of global warming will cause an increase in herbivory by insects. This conclusion was based on the supposed effect of temperature on herbivores but did not consider an effect of temperature on plant growth. 2. We studied the effect of temperature on grazing pressure by the small China-mark moth (Cataclysta lemnata L.) on Lemna minor L. in laboratory experiments. 3. Between temperatures of 15 and 24 degrees C we found a sigmoidal increase in C. lemnata grazing rates, and an approximately linear increase in L. minor growth rates. Therefore, an increase in temperature did not always result in higher grazing pressure by this insect as the regrowth of Lemna changes also. 4. At temperatures below 18.7 degrees C, Lemna benefited more than Cataclysta from an increase in temperature, causing a decrease in grazing pressure. 5. In the context of global warming, we conclude that rising temperatures will not necessarily increase grazing pressure by herbivorous insects.
The strength of limiting factors for duckweed during algal competition
Szabo, S. ; Roijackers, R.M.M. ; Scheffer, M. ; Borics, G. - \ 2005
Archiv für Hydrobiologie 164 (2005)1. - ISSN 0003-9136 - p. 127 - 140.
voedingsstoffen - verwijdering - lemna - algen - groeitempo - concurrentie tussen planten - eutrofiëring - waterkwaliteit - nutrients - removal - algae - growth rate - plant competition - eutrophication - water quality - waste-water treatment - common duckweed - lemna-gibba - performance - growth - ph - macrophytes - toxicity - nitrogen
Duckweed (Lemna gibba) growth was found to be strongly reduced by unicellular green algae (Scenedesmus conspicua, Chlorella sp., Chlamydomonas sp.) in indoor experiments. These algae reduced N, P, Fe and Mn concentrations of the medium drastically, moreover they increased the pH beyond 10. Subsequent additions of nutrients and pH neutralisation removed the growth inhibition of duckweed. This growth inhibition is, therefore, concluded to be due to pH increase and N, P and trace element (Fe, Mn) removal. Of the five factors significantly inhibiting duckweed growth, depletion of N was strongest, increase in pH was second, followed by reduction of P > Fe > Mn.
Nutrients valorisation via duckweed-based wastewater treatment and aquaculture
El-Shafai, S.A.A.M. - \ 2004
University. Promotor(en): H.J. Gijzen; F. El-Gohary, co-promotor(en): Johan Verreth; P. van der Steen. - [S.l.] : Balkema - ISBN 9058089568 - 174
afvalwaterbehandeling - aquacultuur - lemna - voedingsstoffen - egypte - waste water treatment - aquaculture - nutrients - egypt
Experimental analysis of the competition between algae and duckweed
Roijackers, R.M.M. ; Szabo, S. ; Scheffer, M. - \ 2004
Archiv für Hydrobiologie 160 (2004)3. - ISSN 0003-9136 - p. 401 - 412.
lemna - concurrentie tussen planten - eutrofiëring - algen - voedingsstoffen - beschaduwen - nederland - gelderland - plant competition - eutrophication - algae - nutrients - shading - netherlands - ditches - lake
We performed indoor competition experiments between algae and Lemna gibba L. in order to unravel mechanisms of competition. To separate effects of shading and physical interference from nutrient competition we grew the two groups physically separated while sharing the same water. A multifactorial design was used with five levels of initial nitrogen concentration (0.1- 50 mg N l-1) and four shade levels mimicking 0 -100 % duckweed shade on the algal compartment
We performed indoor competition experiments between algae and Lemna gibba L. in order to unravel mechanisms of competition. To separate effects of shading and physical interference from nutrient competition we grew the two groups physically separated while sharing the same water. A multifactorial design was used with five levels of initial nitrogen concentration (0.1-50mg N l(-1)) and four shade levels mimicking 0-100% duckweed shade on the algal compartment. In the experiments in which algae were not shaded, the growth rate of Lemna was reduced strongly (60-62%) at moderate initial nitrogen concentrations (0.1-1 mg N l(-1)). The impact of algae was less at high N-loading and if algae were shaded. The reduction in the chlorophyll content of the fronds was even more dramatic (72-80%). Analyses of nutrients and pH indicated that algae inhibited the growth of Lemna by the removal of N, P and Fe, but also by their photosynthetic effect on pH. When algae and duckweeds were grown together, floating algae occurring at high nutrient levels partly covered the duckweeds and reduced the growth further than in the absence of physical contact. Since under those conditions Lemna growth was still marked, it seems likely that on the long run Lemna will always expand sufficiently to outcompete the algae at high nutrient levels.
Nitrogen transformations and removal mechanisms in algal and duckweed stabilisation ponds
Zimmo, O. - \ 2003
University. Promotor(en): H.J. Gijzen, co-promotor(en): N.P. van der Steen. - S.l. : Balkema - ISBN 9058088111 - 143
afvalwaterbehandeling - stikstof - verwijdering - algen - lemna - bezinkingsvijvers - waste water treatment - nitrogen - removal - algae - stabilization ponds
Effects of light and phytochrome in heterotrophic growth of Lemna minor L.
Rombach, J. - \ 1976
Landbouwhogeschool Wageningen. Promotor(en): E.C. Wassink, co-promotor(en): C.J.P. Spruit. - Wageningen : Veenman - 115
lemnaceae - lemna - fotosynthese - groei - photosynthesis - growth
<p/>Axenic cultures of <em>Lemna minor</em> L. <em></em> were grown on a medium containing sugars and amino acids. In continuous darkness the growth rate was one-tenth of the maximum in continuous light. In darkness early death revealed a thiamine deficiency; this deficiency was counteracted, without increasing the multiplication rate, by feeding the plants thiamine or its thiazole component. The rate of cell division, the rate of frond expansion, and the frond multiplication rate were increased by illumination; at low intensities this increase was in the nature of a photostimulus effect. The increase in growth rate was accompanied by a decrease in dry weight. The sugar uptake from the medium per frond per day was constant, independent of the light intensity and multiplication rate. At intensities of above 100 μW cm <sup><font size="-1">-2</font></SUP>continuous red light, the multiplication rate increased in proportion to the rate of photosynthesis.<p/>Periodic brief illuminations yielded a stimulation of the frond multiplication rate of up to 4 times the dark value. Red illuminations of 2 minutes every 48 hours were sufficient to prevent thiamine deficiency; this effect of the red illuminations was reversible by far red. Stimulation of the multiplication rate was likewise reversible by far red; the effect of continuous low intensity red light was reduced by a simultaneous far red irradiation, while the effect of brief illuminations was reduced by far red following the red. From this it was concluded that phytochrome is a photoreceptor for these light effects. The results of experiments with different far red and red illumination schedules suggested that in plants with much phytochrome only a small part of it is active but that the Pfr level in this part decreases at a rate not very different from that of the bulk phytochrome as measured by the spectrophotometer.<p/>Part of the light effect was not reversible by far red. This part increased by increasing the length of the illumination periods, the light intensity, and the number of illuminations per day. In this increase blue light was much more effective than it was in the far red reversible part of the light effect. This indicates a photoreaction different from phytochrome photoconversion.<p/>Kinetin specially increased the far red non-reversible part of the photostimulation. Together with the intensity dependency of this part of the stimulation, this gave rise to the supposition that the non-reversible part of the light effect was limited by the supply of substrates in phytochrome controlled reactions during the light periods. Thus it would seem plausible to assume that the far red non-reversible part is built up during the red and the blue light periods, whereas the reversible part is developed during the intervening dark periods.
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