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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It depends: : effects of soil organic matter in aboveground-belowground interactions in agro-ecosystems
Gils, Stijn Herman van - \ 2017
University. Promotor(en): Wim van der Putten; David Kleijn. - Wageningen : Wageningen University - ISBN 9789463436526 - 176
soil organic matter - agroecosystems - aphidoidea - fertilizers - wheat - rape - crop yield - ecosystem services - nutrient availability - pest control - organic farming - organisch bodemmateriaal - agro-ecosystemen - kunstmeststoffen - tarwe - koolzaad - gewasopbrengst - ecosysteemdiensten - voedingsstoffenbeschikbaarheid - plagenbestrijding - biologische landbouw

Over the last decades agricultural production increased drastically due to the use of external inputs. However, the use of external inputs has high environmental costs and may negatively influence ecosystem processes such as pollination and pest control that underpin agricultural production. Soil organic matter has been proposed as a potential alternative to external inputs as it relates to multiple yield promoting ecosystem processes. The aim of my thesis is to assess whether and how soil organic matter content alters the effect of some ecosystem processes and external inputs on crop yield. I examined whether soil organic matter alters biomass of wheat and oilseed rape under fertilizer supply. Other biotic and abiotic factors that operate at different spatial and temporal scales are also included in some of these experiments. I found that under controlled conditions soil organic matter may reduce the positive effect of mineral fertilizer supply on crop biomass. The reduction changed with the presence or absence of a pathogenic root fungus, but not with drought stress. Moreover, soil organic matter enhances performance of aphids under controlled greenhouse conditions, but the enhancement was less than fertilizer supply. None of these controlled experiments, however, showed that soil organic matter can be an alternative to mineral fertilizer supply. Under field conditions soil organic matter did not strongly affect plant nutrient availability or performances of aphid and its natural enemies. The relation between soil organic matter and plant biomass in a greenhouse experiment did not change with organic management or the duration of it, neither did it change with pollinator visitation rate, an ecosystem process that is managed on the landscape scale. These results suggest that soil organic matter may relate to ecosystem services that influence crop yield, whereas these relations might not be significant under field conditions. Collectively, all these results suggest that the relation between soil organic matter content and ecosystem processes that benefit crop yield is highly context dependent. I propose future research may focus on (1) the quality of soil organic matter rather than the content per se and (2) the relation between soil organic matter content and crop yield under realistic conditions in a longer term.

Technical documentation of the soil model VSD+ : Status A
Mol-Dijkstra, J.P. ; Reinds, G.J. - \ 2017
Wageningen : Statutory Research Tasks Unit for Nature & the Environment (WOt-technical report 88) - 88
soil - soil acidity - models - nutrient availability - soil carbon sequestration - climatic change - precipitation - bodem - bodemaciditeit - modellen - voedingsstoffenbeschikbaarheid - koolstofvastlegging in de bodem - klimaatverandering - neerslag
VSD+ is een model om de gevolgen te berekenen van atmosferische depositie en klimaatverandering voorbodemverzuring, de beschikbaarheid van voedingsstoffen en het vastleggen van koolstof. Het model isontwikkeld ter onderbouwing van strategieën om de uitstoot van zwavel (S) en stikstof (N) in Europa teverminderen. Dit document biedt een samenvatting van de theorie waar het model op gestoeld is, detechnische documentatie hiervan alsmede een beschrijving van het testen, het valideren en de sensitiviteitsanalysevan het model. De processen zoals beschreven in het artikel over VSD+ zijn met goed gevolg getest.De gevoeligheidsanalyse gaf aan dat de constante voor het evenwicht tussen H+ en Al3+ in de bodemoplossingen de Ca-verweringssnelheid de parameters zijn, die voor een groot gedeelte de waarde van degesimuleerde pH bepalen. Voor basenverzadiging zijn de belangrijkste parameters de uitwisselingsconstantetussen H+ en basische kationen en de verwering van Ca. Voor de C/N ratio van bodemorganische stof zijn Cen N in het strooisel en de opname van N zeer bepalende factoren. De nitraatconcentratie hangt sterk samenmet het nerslagoverschot en de netto input van N---VSD+ is a model to calculate effects of atmospheric deposition and climate change on soil acidification,nutrient availability and carbon sequestration. The model has been developed to support emission abatementstrategies of sulphur (S) and nitrogen (N) in Europe. This document contains a summary of the modeltheory, technical documentation and descriptions of testing, validations and the sensitivity analysis of themodel. The processes described in the paper about VSD+ have been tested successfully. The sensitivityanalysis showed that the constant for the equilibrium between H+ and Al3+ in the soil solution and theweathering rate of Ca are the parameters that to a large extent determine the value of the simulated pH. Forbase saturation, most important parameters are the exchange constant between H+ and base cations andthe weathering of Ca. For the C/N ratio of soil organic matter, litterfall of C and N and the uptake of N areimportant influencing factors. The nitrate concentration strongly depends on the leaching flux and the net N input
Arme bossen verdienen beter : OBN Deskundigenteam Droog zandlandschap
Burg, A. Van den; Bijlsma, R.J. ; Bobbink, R. - \ 2015
VBNE, Vereniging van Bos- en Natuurterreineigenaren - 24 p.
bossen - bosbeheer - zandgronden - zure regen - voedingsstoffenbeschikbaarheid - biodiversiteit - verzuring - voedingsstoffenbalans - verstoorde bossen - bosecologie - forests - forest administration - sandy soils - acid rain - nutrient availability - biodiversity - acidification - nutrient balance - disturbed forests - forest ecology
Bossen van het droog zandlandschap van Noordwest- Europa staan bekend als ‘arme bossen’. Het landschap waarin ze voorkomen was tot in de 20ste eeuw overwegend een heidelandschap. Op de voedselarme heide- en stuifzandbodems zijn vanaf 1900 vooral naaldbossen geplant. Inmiddels zijn in deze voormalige plantages volop kenmerken aanwezig van oudere, meer natuurlijke bossen, zoals dikke levende en dode bomen, natuurlijke verjonging van inheemse loofbomen en een gevarieerd lichtklimaat. Veel soorten hebben sterk geprofiteerd van deze natuurlijke ontwikkeling die nog steeds doorzet. In de loop van 20ste eeuw zijn echter eerst zwaveldepositie (‘zure regen’) en later ook stikstofdepositie een grote negatieve invloed gaan uitoefenen op het landschap. Dit raakt niet alleen de biodiversiteit, maar ook de hout- en biomassaproductie en daarmee de duurzaamheid van het bosgebruik. We hebben directe gevolgen vastgesteld voor soorten en nutriëntenvoorraden in de bodem en indirecte effecten op concurrentieverhoudingen en voedselketens. Er zijn echter ook onzekerheden en belangrijke kennisleemten waar het gaat om de precieze mechanismen, het experimenteel vastleggen van oorzaak-gevolg relaties en mogelijke oplossingsrichtingen. De achtergronden van deze problematiek in droge bossen staan centraal in deze brochure.
Ky’osimba Onaanya: understanding productivity of East African Highland banana
Taulya, G. - \ 2015
University. Promotor(en): Ken Giller, co-promotor(en): Peter Leffelaar; P.J.A. van Asten. - Wageningen : Wageningen University - ISBN 9789462575615 - 167
bananen - musa - droogte - voedingsstoffenbeschikbaarheid - kalium - stikstof - kunstmeststoffen - afrika - uganda - gewasgroeimodellen - beslissingsmodellen - drogestofverdeling - groeianalyse - licht - fenotypische variatie - bananas - drought - nutrient availability - potassium - nitrogen - fertilizers - africa - crop growth models - decision models - dry matter distribution - growth analysis - light - phenotypic variation

Over 30 million people in East Africa depend on East African highland bananas for food and income. The bananas are grown with limited additions of nutrients and no irrigation, despite widespread poor soil fertility and regular dry seasons. This thesis describes the effect of increasing rainfall and application of potassium and nitrogen fertilizers on banana growth and yields. In areas that receive less than 1100 mm of rainfall per year, additional rainfall increases yields by 65%. Application of potassium increases yields by 88%, while nitrogen is not required. A framework for computing banana growth and yield in response to the amount of water stored in the soil is described. Where the soil water storage capacity is low, mulching increases yields by 10% but it has no effect in areas where the soil water storage is high. This framework is envisaged to guide improvements in banana management and productivity in East Africa.

Mineral nutrition of cocoa : a review
Vliet, J.A. van; Slingerland, M.A. ; Giller, K.E. - \ 2015
Wageningen : Wageningen UR - ISBN 9789462577053 - 57
cacao - mineralenvoeding - bevruchting - kunstmeststoffen - mestbehoeftebepaling - vruchtbaarheid - voedingsstoffenbehoeften - voedingsstoffenbeschikbaarheid - grondanalyse - voedingsstoffentekorten - kaliummeststoffen - stikstofmeststoffen - fosformeststoffen - agrarische productiesystemen - overzichten - cocoa - mineral nutrition - fertilization - fertilizers - fertilizer requirement determination - fertility - nutrient requirements - nutrient availability - soil analysis - nutrient deficiencies - potassium fertilizers - nitrogen fertilizers - phosphorus fertilizers - agricultural production systems - reviews
This literature review on mineral nutrition of cocoa was commissioned by the Scientific Committee of the Cocoa Fertiliser Initiative to address the following questions: What knowledge is currently available about mineral nutrition of cocoa? What are the current knowledge gaps? What are the key areas for further research?
Nitrogen: The most important nutritional element for the plant : complicated balance between vegetative and generative growth
Heuvelink, E. ; Kierkels, T. - \ 2015
In Greenhouses : the international magazine for greenhouse growers 4 (2015)2. - ISSN 2215-0633 - p. 44 - 45.
glastuinbouw - plantenvoeding - voedingsstoffen - voedingsstoffenbeschikbaarheid - opname (uptake) - plantenfysiologie - nitraten - ammonium - cultuurmethoden - greenhouse horticulture - plant nutrition - nutrients - nutrient availability - uptake - plant physiology - nitrates - cultural methods
Nitrogen is found in almost all parts of the plant. It’s one of the plant’s most essential nutritional element. There’s a tendency in greenhouse horticulture to over-fertilise. In most situations it’s difficult to get around this. However, more precise application offers more possibilities to control production.
Population densities of eastern black rhinoceros : unravelling the controls
Ouma, B.O. - \ 2014
University. Promotor(en): Herbert Prins, co-promotor(en): Ignas Heitkonig; Sip van Wieren. - Wageningen : Wageningen University - ISBN 9789461739599 - 158
rhinoceros - populatiedichtheid - populatie-ecologie - savannen - afgrazen - voedingsstoffenbeschikbaarheid - regen - temperatuur - kenya - population density - population ecology - savannas - browsing - nutrient availability - rain - temperature

Key words: black rhinoceros, browser, corticosterone, diet, density dependence, minerals, moisture, physiological stress, savanna, soil nutrients, woody cover.

Understanding the forces that cause variability in population sizes is a central theme in ecology. The limiting factor in populations of large mammals which are not controlled top‐down by predation is food, i.e., such populations are controlled by bottom‐up processes. However, there is little evidence of density dependence in large‐ to mega-herbivores. Yet, conservationists have managed Critically Endangered mega‐herbivores like rhinoceros as if their population growth were density dependent, i.e., following a logistic growth curve, focusing on large growth at population densities presumed to be at half‐carrying capacity (K/2). This would enable them to translocate animals at presumed half‐carrying capacity to retain local population densities and to create new populations in areas of suitable habitat, where animals are considered safe against poaching. This study focused on one such mega‐herbivore, the eastern black rhinoceros (Diceros bicornis michaeli) to re‐consider the density dependence population regulation in a mega‐herbivore and uses the findings to contribute to possible solutions towards conservation challenges facing this species. The expectations were that increases in population density would result in a decrease in reproductive performance, and that physiological stress levels in animals in populations of high density would be higher than in animals in populations of low densities. Nine populations of black rhinoceros across Kenya were studied, with variation in their respective densities, Plant Available Moisture (‘PAM’ i.e., ‘soil moisture’) and Plant Available Nutrients (‘PAN’ i.e., ‘soil fertility’). Data from available records (1993‐2010) were used to assess reproductive performance. Dietary quality and levels of corticosterone were estimated through faecal analysis from animals sampled in the field and from data on feeding trials of black rhinoceroses in zoos (dietary analysis only). Woody cover estimates were used to assess available browse for black rhinoceros. Two measures of density were used, i.e., absolute density (animals/km2) and relative density, i.e., absolute density as a ratio to the estimated maximum stocking density or ‘carrying capacity’. The effects of PAM and PAN, and subsets of PAM (rainfall and temperature) were incorporated and controlled in testing expectations. No evidence for density dependence was found. Reproductive performances tended to be better where PAM was high, PAN was low and woody cover was sparse. PAM was found to be directly correlated with quality of dietary browse. Black rhinoceros populations appeared controlled more by bottom‐up processes through key resources, even though their densities were perhaps too low to fully support this alternative view. It was apparent that the density dependence concept still requires more investigation. Deliberate efforts should be made to secure high PAM – low PAN – sparse woody cover areas for conservation of black rhinoceros. Conservation managers are advised to consider set percentage translocations, as opposed to the current translocation of black rhinoceros on the basis of an imaginary ‘carrying capacity’ and density dependence.

Oosterschelde geschikt als habitat voor bruinvis?
Jansen, O.E. ; Aarts, G.M. ; Reijnders, P.J.H. - \ 2013
Zoogdier 24 (2013)4. - ISSN 0925-1006 - p. 4 - 6.
phocoenidae - oosterschelde - habitats - habitatgeschiktheid - voedingsstoffenbeschikbaarheid - stormvloedkeringen - ecologische risicoschatting - wildbeheer - eastern scheldt - habitat suitability - nutrient availability - storm surge barriers - ecological risk assessment - wildlife management
Sinds tientallen jaren zijn er weer meer bruinvissen waargenomen in de Noordzee rond Nederland. De dieren drongen onlangs ook door in estuaria, zoals de Oosterschelde. Maar is het habitat in de Oosterschelde eigenlijk wel geschikt voor de bruinvis en is er voldoende voedselaanbod en rust? En welke impact heeft de stormvloedkering op deze kleine walvisachtige? Informatie die bijdraagt aan een antwoord op bovenstaande vragen kwam boven water gedurende het onderzoek van Okka Jansen, waarop zij begin 2013 promoveerde.
Eindrapportage organische meststoffen: samenstelling en werking
Haan, J.J. de; Geel, W.C.A. van; Paauw, J.G.M. ; Burgt, G.J.H.M. van der; Hospers-Brands, A.J.T.M. ; Venhuizen, A. ; Oonk, K. - \ 2013
Lelystad : Praktijkonderzoek Plant & Omgeving, Business Unit Akkerbouw, Groene Ruimte en Vollegrondsgroenten - 13
bemesting - akkerbouw - organische meststoffen - samenstelling - voedingsstoffenbeschikbaarheid - gebruikswaarde - mineralenboekhouding - modules - onderzoeksprojecten - fertilizer application - arable farming - organic fertilizers - composition - nutrient availability - use value - nutrient accounting system - research projects
De mest- en mineralen wetgeving is en wordt verder aangescherpt. Telers moeten daardoor steeds scherper het aanbod van meststoffen afstemmen op de gewasbehoefte. Bij gebruik van kunstmest is dat makkelijker dan bij gebruik van organische mestsoorten en composten. Deze beweging veroorzaakt dus een tendens naar verminderd gebruik van organische meststoffen. Dat is om diverse redenen een zorgelijke ontwikkeling, o.a. door een lagere organische stof aanvoer. Door beter gebruik te maken van de aanwezige kennis, zowel oude als recente, kan de onzekerheid over de werking van de meststoffen voor een deel weggenomen worden en kunnen ook betere keuzes gemaakt worden in de organische meststoffen die goed bij gewas en bedrijf passen. Daardoor kan het gebruik van organische meststoffen bevorderd worden en kan de mineralenbenutting uit die meststoffen verhoogd worden.
Strategies to reduce losses and improve utilisation of nitrogen from solid cattle manure
Shah, G.M. - \ 2013
University. Promotor(en): Oene Oenema, co-promotor(en): Egbert Lantinga; Jeroen Groot. - S.l. : s.n. - ISBN 9789461735188 - 156
stikstof - dierlijke meststoffen - ammoniakemissie - mineralisatie - stikstofverliezen - stikstofbalans - bodem - uitspoelen - rundveemest - opslag - voedingsstoffenbeschikbaarheid - nitrogen - animal manures - ammonia emission - mineralization - nitrogen losses - nitrogen balance - soil - leaching - cattle manure - storage - nutrient availability

Background and objectives

The number of domesticated cattle in the world has steadily increased during the last decades, and thereby also the amount of manure produced annually. The excrements of grazing cattle are dropped in pastures and left unmanaged, but that of confined and housed cattle are collected and managed. The collected manure is often a variable mixture of urine, faeces, bedding material and spoiled feed and (drinking) water. On most modern farms, excrements are usually collected in leak-tight storages and handled as slurry: a mixture of urine, faeces and spoiled water. However, on a significant fraction of farms, cattle excrements are ‘source-separated’ in a liquid fraction and a solid fraction. The solid cattle manure (SCM) is usually a mixture of faeces and bedding material with some absorbed urine. The production of SCM is increasing due to the renewed interest in straw-based housing systems for better animal health and welfare. It has been observed that a significant loss of N can occur, especially from the storage and application phases of the SCM management chain. This N loss pollutes the air, groundwater and surface waters, and also reduces its N fertiliser value. Thus the challenge is to develop an effective SCM management system that retains as much of the excreted N in the system as possible, and thereby improving on-farm N cycling through the cattle-manure-soil-crop continuum (Chapter 1). Themain objective of this PhD thesis research was to increase the understanding of the factors controlling N losses during storage and after field application, and to develop and test strategies to decrease N losses and improve crop utilisation of N from SCM. The specific objectives were:

To study the interactions between a number of animal manures and soil types on N mineralisation and plant N recovery (Chapter 2) To investigate the effects of storage conditions on (i) magnitude and pathways of C and N losses during storage of SCM, and (ii) crop apparent N recovery (ANR) and DM yield (Chapter 3) To examine manure disappearance rates, N release pattern and herbage ANR during the year of application and the year thereafter from surface applied SCM subjected to different storage conditions (Chapter 4), and To analyse the effect of various application strategies on NH3 emission and/or crop ANR from applied SCM to grassland and arable (maize) land (Chapters 3 and 5)

To pursue these objectives a pot experiment in a glasshouse (Chapter 2) and a number of field experiments (Chapters 3 to 5) were conducted on experimental facilities of Wageningen University, the Netherlands. The pot experiment dealt with net N mineralisation and herbage ANR from SCM, cattle slurry and poultry manure, all applied to peat, sandy and clay soils. The field experiments examined (i) total C and N losses from stockpiled, composted, covered and roofed SCM heaps, (ii) manure decomposition, N release and herbage ANR after surface application of fresh and stored SCM on grassland, and (iii) the effects of irrigation and soil incorporation after SCM application, and lava meal as an additive on NH3 emission and/or crop ANR by grassland herbage or arable maize.

Major findings of the thesis

Results of the pot experiment showed that net N mineralisation and herbage ANR varied as function of manure storage method and soil type. Irrespective of the manure types, net N mineralisation and herbage ANR were highest in peat soil, which was characterised by the greatest N delivering capacity. Between the clay and sandy soils, both having similar N delivering capacity, net N mineralisation and herbage ANR were lower in the clay soil than in the sandy soil, likely because of immobilisation and fixation of ammonium-N by its inherited higher clay content. On each soil type,ANR was lower from SCM than cattle slurry and poultry manure(Chapter 2). The N recovery fraction was low when SCM was stored traditionally (i.e. stockpiling or composting) due to (i) loss of the initial mineral N content and readily degradable organic N compounds, and (ii) conversion of part of the remaining N into more stable forms as compared to that originally present before storage. Up to 31% of the initial total N from the stockpiled and 46% from the composted SCM heaps were lost during a period of about four months. Covering and roofing of SCM heaps reduced the losses down to 6 and 12%, respectively. Of the total N losses from each storage method, only about one fourth could be traced back as NH3-N and N2O-N emissions, and/or N leaching. The remainder could not be accounted for and constituted, in all probability, of harmless N2 gas. Of the total measured gaseous and liquid N losses together, N leaching contributed the most. The leaching N losses were reduced by almost three times through protection of SCM heap against precipitation either by its covering or roofing when compared to its stockpiling or composting in the open air. Although stockpiling of SCM under a roof significantly reduced overall total N losses, NH3 and N2O emissions were much higher as compared to stockpiling of SCM in the open air. Composting of SCM resulted in higher gaseous N emissions as well as N leaching with respect to the other storage methods. In view of these finding I conclude that covering of SCM heaps with an impermeable sheet is the best option to reduce storage N losses (Chapters 3 and 4).

In addition, because of N conservation and slow mineralisation of the organically bound N during the covered storage, mineral N content of SCM increased at the end of the storage phase. This, together with high mineralisation activities after field application of covered SCM, led to greater crop ANR and DM yield especially when compared to composted SCM, both in the year of application and in the subsequent year. When N losses during storage was taken into account to arrive at the crop ANR of the collected manure from the barn, it turned out that the ANR value was about three times larger in case of covered storage compared to composting of SCM, both for grassland (21 vs. 7%; Chapter 4) and arable land (37 vs. 13%, Chapter 3). Interestingly, despite of some N losses during covered storage (~10% of the initial N), crop ANR and DM yield were significantly larger from covered than fresh SCM taken directly from the barn, again in both situations.

Irrigation immediately after SCM spreading and use of lava meal as an additive significantly (i) reduced NH3 emission and (ii) improved crop ANR as well as DM yield (Chapters 3 and 5).Irrigation at a level of 5 mm immediately after surface application of fresh and covered SCM to grassland reduced NH3 emission by 30 and 65%, respectively, whereas it was not effective in case of composted SCM, likely because of its greater DM content. Addition of lava meal before application at a rate of 80 g per kg of covered SCM resulted in an emission reduction of 46%. By combining it with 10 mm irrigation, an almost 100% reduction in NH3 emissions from covered SCM was realised, whereas herbage ANR increased from 18 to 26% of the applied N over a growing period of five months (Chapter 5). Incorporation of SCM just before sowing of maize resulted in an ANR value of 39% from covered SCM, whereas this fraction was 20, 29 and 31% in case of composted, stockpiled and roofed manure, respectively (Chapter 3).

Overall conclusions

The ANR from applied manure in harvested herbage depends on manure type and soil type, and varies widely. It is lower from SCM than from cattle slurry Total N losses during storage of SCM can be reduced remarkably by covering the heap with an impermeable sheet. Covering reduced two N loss pathways: (i) gaseous N emissions to air, and (ii) N leaching to surface waters and groundwater. Field application of SCM that was covered by a sheet during storage, decomposed faster and more N was available for plant uptake, both in the year of application and the subsequent year, when compared to SCM that was stored in traditional ways Emission of NH3 following land application of SCM can be reduced greatly by irrigation or incorporation immediately after SCM spreading, and using lava meal as an additive. Irrigation appeared to be more effective in reducing NH3 emission than the addition of lava meal. All these NH3 emission abatement measures substantially increased crop ANR and DM yield Overall, combining covered storage with either direct irrigation following application of SCM to vegetated soil or direct incorporation in the soil following application of SCM to arable land is the best practical option to reduce losses and improve utilisation of N from SCM management systems. Depending on the farm infrastructure, losses may be further reduced by the use of lava meal, preferably as a bedding additive in the barn

Implication for efficient manure management

In many industrialised countries, animal manure is a major source of environmental pollution. In contrast, in most of the developing countries animal manure is considered as a key nutrient source to maintain or improve crop productivity and therefore N losses from manure management are more seen as ‘loss of plant nutrient’ rather than ‘pollution problems’. In either case development of efficient SCM management systems is highly important. Based on the results of this thesis, I propose some key management actions to improve the agro-environmental value of SCM.

If economically attractive, apply lava meal to straw bedding in the barn (Chapter 5) Store the barn-produced SCM under impermeable sheet (Chapters 3 and 4) Crop and soil-specific SCM application rates must take into account the potential available N (Chapter 2) and degradability of organic N compounds (Chapter 4) Incorporate the SCM from covered storages directly into the soil when applied to arable land (Chapter 3) In situations where incorporation is not feasible, like on grassland, spread SCM just before a predicted rainfall event or apply irrigation otherwise (Chapter 5) Take into account the expected residual N contribution from earlier manure input when determining the manure application rate(Chapter 4)
Evaluation of the NDICEA model
Rietberg, P.I. ; Burgt, G.J.H.M. van der - \ 2012
Driebergen : Louis Bolk Institute (Publication 2012-026 LbP) - 39 p.
bemesting - modellen - beslissingsmodellen - stikstof - stikstofmeststoffen - stikstofkringloop - voedingsstoffenbeschikbaarheid - fertilizer application - models - decision models - nitrogen - nitrogen fertilizers - nitrogen cycle - nutrient availability
Within the N-Toolbox project the NDICEA nitrogen model, one of the key tools in the virtual Toolbox, has been improved and tested in England, Denmark and Spain. The model performance was evaluated on datasets from these three countries by means of visual observation, RMSE and RSR from the soil nitrogen dynamics. In England the scenarios with organic fertilizer performed better than those with artificial fertilizer, leading to the suggestion that the calculated nitrogen release out of fertilizer could be improved. Timing of the soil sampling on soil inorganic nitrogen is important to realize a good model evaluation; two samples only, before sowing and after harvest, is not enough. When soil mineral nitrogen samples were taken during crop growth, model calculation and measured values showed sometimes big differences. It is suggested to improve the plant nitrogen uptake sub-model.
Stikstofwerking van mest op bouwland : informatieblad 46
Schröder, J.J. - \ 2012
bouwland - bemesting - dierlijke meststoffen - nitraatuitspoeling - voedingsstoffenbeschikbaarheid - stikstof - veldproeven - ondergewassen - akkerbouw - arable land - fertilizer application - animal manures - nitrate leaching - nutrient availability - nitrogen - field tests - catch crops - arable farming
Informatieblad Mest, Milieu en Klimaat over een proef naar de stikstofwerking van dierlijke mest. De conclusie van deze proef is dat als aan dierlijke mest een juiste N-werking wordt toegekend, de uitspoeling van N uit mest op korte termijn niet hoger is dan bij gebruik van kunstmest-N. Voor zover uitspoeling dreigt op te treden, kunnen tijdig gezaaide vanggewassen de N-uitspoeling verlagen en de N-beschikbaarheid voor een volgteelt verhogen.
Telen bij lage fosfaatniveaus in de biologische landbouw; achtergronden en literatuurstudie : het gedrag van fosfaat in de bodem en de interactie met gewassen
Timmermans, B. ; Sukkel, W. ; Bokhorst, J. - \ 2012
Kennisakker.nl 2012 (2012)16 aug.
fosfaat - bodemchemie - bemesting - biologische landbouw - voedingsstoffenbeschikbaarheid - akkerbouw - phosphate - soil chemistry - fertilizer application - organic farming - nutrient availability - arable farming
Fosfaat is belangrijk in de biologische landbouw. Het opraken van fossiele voorraden en emissies naar het oppervlaktewater maken het noodzakelijk het gebruik van fosfaatmeststoffen te beperken en kringlopen na te streven. In de praktijk van de biologische landbouw is er al gauw een fosfaatoverschot op de mineralenbalans wanneer men niet oplet. Aan de andere kant blijkt dat er in de praktijk ook goed geteeld kan worden bij zeer lage fosfaatgehalten in de bodem. Redenen genoeg om een en ander nader te analyseren.
Telen bij lage fosfaatniveaus in de biologische landbouw; achtergronden en literatuurstudie
Timmermans, B.G.H. ; Sukkel, W. ; Bokhorst, J.G. - \ 2012
[Driebergen] : Louis Bolk Instituut (Publicatie / Louis Bolk Instituut nr. 2010-029 LbP) - 32
bemesting - fosfaat - fosformeststoffen - bodemvruchtbaarheid - voedingsstoffenbeschikbaarheid - bodemonderzoek - akkerbouw - biologische landbouw - fertilizer application - phosphate - phosphorus fertilizers - soil fertility - nutrient availability - soil testing - arable farming - organic farming
In de praktijk van de biologische landbouw is er al gauw een fosfaatoverschot op de mineralenbalans wanneer men niet oplet. Aan de andere kant blijkt dat er in de praktijk ook goed geteeld kan worden bij zeer lage fosfaatgehalten in de bodem. Redenen genoeg om een en ander nader te analyseren. Dit literatuuronderzoek zet kennis maar ook open vragen omtrent het gedrag van fosfaat in de bodem en de interactie met gewassen op een rij.
Zoeken naar mogelijkheden voor efficiënter N-gebruik op zand
Haan, J.J. de - \ 2012
Groenten en Fruit Actueel 2012 (2012)18. - ISSN 0925-9694 - p. 13 - 13.
bodemvruchtbaarheid - grondbewerking - minimale grondbewerking - bemesting - stikstof - zandgronden - voedingsstoffenbeschikbaarheid - akkerbouw - veldproeven - soil fertility - tillage - minimum tillage - fertilizer application - nitrogen - sandy soils - nutrient availability - arable farming - field tests
In het project 'Bodemkwaliteit op zandgrond' werkt PPO aan de ontwikkeling van een strategie voor niet-kerende grondbewerking en vergelijkt het diverse organische-stof-beheerstrategieën. Achterliggende reden is de zoektocht naar mogelijkheden om aan de nitraatnorm te voldoen.
Bemestingsadvies
Hoeks, P. ; Middelkoop, J.C. van; Philipsen, A.P. ; Talens, B. ; Bussink, D.W. ; Bos, A.J. ; Velthof, G.L. ; Schroder, J.J. ; Abbink, G. ; Eekeren, N.J.M. van; Dijk, W. van - \ 2012
Lelystad : Animal Sciences Group, Commissie Bemesting Grasland en Voedergewassen - 179
bemesting - graslandbeheer - voedergewassen - voedergranen - voederbieten - maïs - luzerne - bodemvruchtbaarheid - grondanalyse - voedingsstoffenbeschikbaarheid - consultancy - dierlijke meststoffen - richtlijnen (guidelines) - stikstofmeststoffen - veehouderij - fertilizer application - grassland management - fodder crops - feed grains - fodder beet - maize - lucerne - soil fertility - soil analysis - nutrient availability - animal manures - guidelines - nitrogen fertilizers - livestock farming
Deze uitgave geeft de meest actuele versie van de officiële bemestingsadviezen. De "Adviesbasis voor de bemesting van grasland en voedergewassen" is bedoeld voor laboratoria voor grondonderzoek ten behoeve van hun bemestingsadvisering, voorlichtingsdiensten, handel, industrie, onderwijs en onderzoek. Daarnaast is hij ook bedoeld voor de praktische boer die behoefte heeft aan meer achtergrondinformatie omtrent bemesting. De opgenomen bemestingsadviezen zijn vastgesteld door de Commissie Bemesting Grasland en Voedergewassen. Deze commissie is ingesteld door LTO-Nederland en bestaat uit vertegenwoordigers van onderzoek, voorlichting en bedrijfsleven.
Landbouwkundige en milieukundige perspectieven van mineralenconcentraten : deskstudie in het kader van de Pilot Mineralenconcentraten
Ehlert, P.A.I. ; Hoeksma, P. - \ 2011
Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2185) - 76
dierlijke meststoffen - mineralen - concentraten - kunstmeststoffen - stikstof - mestverwerking - voedingsstoffenbeschikbaarheid - animal manures - minerals - concentrates - fertilizers - nitrogen - manure treatment - nutrient availability
Mineralenconcentraten als kunstmestvervanger is één van de oplossingsrichtingen om de druk op de mestmarkt te verlichten. De Rijksoverheid ondersteunt pilots die mineralenconcentraten maken uit varkens- en runderdrijfmest door middel van omgekeerde osmose. De deskstudie onderzoekt de landbouwkundige en milieukundige perspectieven van mineralenconcentraten en de dikke fractie. Mineralenconcentraten zijn in hoofdzaak oplossingen van minerale stikstof en kalium. Literatuurgegevens wijzen uit dat de werkingscoëfficiënt van stikstof op grond van de samenstelling gelijk is aan die van reguliere minerale stikstofoplossingen maar er zijn onzekerheden bij de bepaling van de werkelijke effectiviteit omdat de mate van ammoniakvervluchtiging, nitrificatie, denitrificatie en immobilisatie na toediening van een mineralenconcentraat niet vast staan. Kalium zal volledige beschikbaar zijn voor het gewas. Het gebruik van de dikke fractie wordt bepaald door fosfor. Bij verantwoord landbouwkundig gebruik binnen het stelsel van gebruiksnormen zijn de vrachten aan cadmium, chroom, koper, kwik, nikkel, lood en zink verantwoord laag. Deze contaminanten vormen geen aandachtpunt.
Concurrentie tussen honingbijen en wilde bijen (2)
Cornelissen, B. ; Visser, A. - \ 2011
Bijenhouden 5 (2011)2. - ISSN 1877-9786 - p. 16 - 16.
wilde bijenvolken - honingbijen - concurrentie tussen dieren - voedingsstoffenbeschikbaarheid - populatiedichtheid - wild honey bee colonies - honey bees - animal competition - nutrient availability - population density
In de vorige editie van Bijenhouden hebben we een algemene inleiding gegeven over de vraag wat concurrentie eigenlijk is en welke factoren er invloed op hebben. In dit artikel willen we kijken in hoeverre concurrentie daadwerkelijk optreedt. Wat is er op dit gebied aan onderzoek gedaan en wat zijn de uitkomsten? Horen honingbijen wel in de Nederlandse natuur thuis en zo ja hoeveel?
Nutrients in an African Savanna: the consequences of supply heterogeneity for plants and animals
Waal, C. van der - \ 2010
University. Promotor(en): Herbert Prins; H. de Kroon, co-promotor(en): Ignas Heitkonig. - [S.l. : S.n. - ISBN 9789085856740 - 151
voedingsstoffen - bodemvruchtbaarheid - heterogeniteit - savannen - bomen - grassen - biologische mededinging - herbivoren - begrazing - afgrazen - foerageren - vegetatie - semi-aride klimaatzones - schaalverandering - voedingsstoffenbeschikbaarheid - zuid-afrika - nutrients - soil fertility - heterogeneity - savannas - trees - grasses - biological competition - herbivores - grazing - browsing - foraging - vegetation - semiarid zones - scaling - nutrient availability - south africa
In savannas, trees and grasses co-exist and share resources such as water and
nutrients. The ratio between the tree and grass components (i.e., vegetation structure)
importantly controls productivity, animal assemblages and earth-atmosphere
feedbacks. As the structure of savanna vegetation is inherently unstable and easily
disturbed, finding out how the vegetation structure is controlled is of great importance
for rangeland management and conservation. Currently four factors are believed to
control the vegetation structure in savannas; namely, water, nutrients, herbivory and
fire. While the water and fire factors have been intensely studied, the roles of nutrients
and herbivores as factors are less well known. Improving our understanding of the
role of nutrients in savannas is relevant, because it is increasingly realised that global
change also alter the availability of nutrients, e.g., increased nitrogen deposition. How
savanna systems respond to nutrient perturbations is uncertain. Changes in soil
nutrient availability are also likely to feed back to changes in forage quality, which
may influence large herbivore use and vegetation impact patterns, thus indirectly
influencing vegetation structure. Moreover, it is increasingly realised that not only
changes in the availability of nutrients influence plants and subsequently herbivores,
but also how nutrients become spatially available. In fact, new ideas suggest that
differences in the scale of spatial resource heterogeneity may control how resources
are partitioned between co-existing species differing in size, e.g., large trees coexisting
with small grasses in savanna systems. To test how changes in nutrient
availability and spatial configurations influence savanna systems, several field
experiments were conducted in a semi-arid savanna in South Africa.
In the study area we found that nutrient (N, P and K) availability negatively
affected tree (Colophospermum mopane) seedling establishment in fertilization
experiments. Also, trees failed to re-colonize nutrient-rich kraal sites that were
abandoned almost half a century ago. In dry savannas, it is currently believed that the
success of tree seedling establishment exercises large control over the relative
dominance of trees, thus an increase in nutrient availability may feed back to a
structurally more open vegetation state. Different explanations may account for
constrained tree seedling establishment under fertile soil conditions. We tested the
hypothesis that the intensification of grass competition reduces tree seedling
recruitment in fertile environments. In controlled competition experiments it was
shown that negative nutrient effects on tree seedlings only occur when seedlings were
competing with grasses in mixtures. Furthermore, we found that adding both water
and nutrients to tree seedling-grass plant mixtures cancelled the negative effects of
added nutrients on tree seedlings. Thus the suppressing effect of increased nutrient
availability on seedlings appears to operate indirectly through the pre-empting of soil
water resources by vigorous herbaceous growth under fertile conditions. Since woody
seedlings are vulnerable to water stress, increased nutrient-induced water stress
translates into higher mortality rates and suppressed growth of tree seedlings in fertile
areas. In support, transplanted tree seedling mortality increased during a mid-season
drought as local fertilizer concentration increased. In conclusion, intensified
herbaceous competition under fertile soil conditions appears to be a viable
mechanism explaining poor tree seedling recruitment under fertile soil conditions.
Savannas and nutrients
While establishing tree seedlings suffer under fertile conditions, our data
suggest that established (mature) tree growth benefitted from an increase in nutrient
availability, especially following an increase in N availability. With regards to
increased atmospheric N deposition, we predict that tree cover may initially expand
following nutrient enrichment in dry savannas, although tree cover responses may be
insensitive to current levels of N deposition. However, in the long-term tree cover is
expected to decline, because of constrained tree recruitment that appears to be more
sensitive to small increases in N availability.
The relative availability of nutrients such as N and P may also influence how
resources are partitioned between co-existing trees and grasses. In a field experiment
we found evidence that trees were relatively more limited by N than P availability. An
East African study has shown that grasses underneath trees are more P than N limited
and we found evidence that the competiveness of sub-canopy grasses in our study
increased when only P was supplied. The relative availability of N vs. P may therefore
offer an additional axis governing resource partitioning between trees (non N-fixing)
and grasses in savanna systems. This supports the idea that organisms with a high
growth potential, apparently grasses in savannas, have relatively high P requirements
to sustain rapid protein synthesis, while slower growing organisms such as trees are
more limited by the availability of N.
The availability of soil nutrients strongly mediated where large herbivores
concentrated their impact in the landscape. Both grazers and browsers responded
positively to fertilization, apparently via the control that soil nutrient availability has
on forage quality. Tree and grass leaf N and P concentrations increased and
condensed tannin concentrations in trees decreased following fertilization. Under high
local soil nutrient concentrations the vegetation biomass was in some instances
reduced below control biomass by herbivores, indicating that top-down herbivore
effects potentially override bottom-up nutrient effects under fertile conditions.
In ecology, it is increasingly realized that it is not only the availability of
nutrients, but also how nutrients become spatially available that matters. Data from a
large field experiment where a gradient in the scale of nutrient patchiness (i.e., patch
grains sizes 2 x 2 m, 10 x 10 m or 50 x 50 m) was created, suggested that the scale of
nutrient patchiness controlled the partitioning of resources between co-existing trees
and grasses. For the same local fertilizer concentration, tree leaf quality was
unresponsive to fertilization in small patches, but responded in the larger patches.
Grass leaf quality increased with local fertilizer concentration regardless of patch size.
The differential responses of trees and grasses to scale differences subsequently
modulated the responses of the browser and grazer guilds. For the same high local
fertilizer concentration, grazers responded to both fine and coarse scales of nutrient
patchiness, while browsers responded only to the coarse scale of nutrient patchiness.
In turn, the selective grazing in the fine scale of nutrient patchiness treatment,
apparently stimulated tree growth. In the coarser scale of patchiness treatment both
browsers and grazer impact intensified locally. Thus the scale of nutrient patchiness
controlled nutrient partitioning between trees and grasses, which was apparently
closely tracked by the large herbivore assemblage, resulting in differential local
impacts on the tree and grass layers. Apart from local effects, the scale of nutrient
patchiness may also regulate the use and quality of forage resources at larger (e.g.,
landscape) scales. In the large field fertilizer experiment, calculations suggest that the
total herbaceous off-take by grazers peaked where the same fertilizer amount (15 kg N
plot-1) was spread over the whole plot surface area rather than concentrated in 10 x 10
m patches. Thus, how nutrients are distributed in an area controls secondary
productivity and where herbivores concentrate their impact.
The scale related patterns observed in the large fertilizer experiment may have
been reinforced by plastic responses (e.g., fine root proliferation in nutrient-rich soil)
to heterogeneous nutrient supplies of trees in the coarse scale treatments and grasses
in the fine scale treatments, respectively. To test this, the same nutrient amount was
supplied at two different scales of patchiness to focal trees with their associated
grasses. Two years after fertilization, large-scale fertilized trees showed increased
shoot growth and increased leaf N concentrations compared to small-scale fertilized
trees receiving the same N amount. Conversely, trees in a small-scale configuration
fertilized with P showed negative responses compared to large-scale counterparts.
These results suggest that differences in the local scale of nutrient patchiness also
influence how nutrients are partitioned between co-existing trees and grasses.
Herbivores not only respond to nutrient heterogeneity, but may also create
spatial heterogeneity in nutrient availability, which, in turn, may influence the
vegetation structure of savannas. We studied the current soil nutrient status, tree and
grass biomass patterns and large herbivore use of nine former livestock holding pen
areas (kraals) in a semi-arid, nutrient poor savanna. These were contrasted with
nearby control sites located in the surrounding landscape. The kraals, formerly
enriched by livestock dung and urine, were abandoned around 1970 and since then
wildlife replaced livestock in these parts. We found that around 40 years later, kraal
soil had elevated concentrations of inorganic N, extractable P, K, Ca and Mg
compared to control sites, which resulted in high quality forage in kraal sites. Trees
also failed to invade these sites, thus kraals remained as structurally open patches in
the otherwise dense savanna. Evidently, wild large herbivores maintain the high
nutrient status of kraal sites, probably by importing nutrients into these sites and by
accelerating local nutrient cycling. In turn, the increased local nutrient availability
prevents tree seedlings from establishing under these fertile conditions.
Finally, this study provided evidence that changes in the availability of
nutrients influenced the success of woody seedling establishment, which may feed
back to changes in the relative proportions of trees and grasses in dry savannas.
Furthermore, this study supports the new idea that the scale of resource heterogeneity
influences how resources are partitioned between co-existing trees and grasses, which,
in turn, modulated browser vs. grazer use and impact patterns on the vegetation.
In conclusion, this study provides new information on nutrient-plant-herbivore
interactions in a dry savanna with potentially important implications for the
management of dry savannas in general.
Aquatic ecosystems in hot water : effects of climate on the functioning of shallow lakes
Kosten, S. - \ 2010
University. Promotor(en): Marten Scheffer, co-promotor(en): Egbert van Nes. - S.l. : s.n. - ISBN 9789085856016 - 160
aquatisch milieu - ecologie - meren - klimaatverandering - waterplanten - fytoplankton - biomassa - kooldioxide - voedingsstoffenbeschikbaarheid - klimaatfactoren - aquatische ecosystemen - aquatische ecologie - aquatic environment - ecology - lakes - climatic change - aquatic plants - phytoplankton - biomass - carbon dioxide - nutrient availability - climatic factors - aquatic ecosystems - aquatic ecology - cum laude
cum laude graduation (with distinction) There is concern that a warmer climate may boost carbon emissions from lakes and promote the chance that they lose their vegetation and become dominated by phytoplankton or cyanobacteria. However, these hypotheses have been difficult to evaluate due to the scarcity of relevant field data. To explore potential climate effects we sampled 83 lakes along a latitudinal gradient of more than 6000 km ranging from Rio Grande do Norte in Brazil to the South of Argentina (5-55 oS). The lakes were selected so as to be as similar as possible in morphology and altitude while varying as much as possible in trophic state within regions. All lakes were sampled once during summer (subtropical, temperate and tundra lakes) or during the dry season (tropical lakes) between November 2004 and March 2006 by the same team. In the first chapters I address the question how climate might affect the chances for shallow lakes to be dominated by submerged plants. It has been shown that temperate lakes tend to have two contrasting states over a range of conditions: a clear state dominated by aquatic vegetation or a turbid state. The turbid state is typically dominated by phytoplankton and often characterized by poorer water quality than the clear state. The backbone of the theory explaining this pattern is a supposed positive feedback of submerged vegetation on water clarity: vegetation enhances water clarity and clearer water, in turn, promotes vegetation growth. The theory furthermore asserts that submerged vegetation coverage diminishes when nutrient concentrations increase until a critical point at which the entire vegetation disappears due to light limitation. Both aspects of the alternative state theory have been well studied in temperate shallow lakes, but the validity of the theory for warmer lakes has been questioned. In chapter 2 a graphical model is used to show how climate effects on different mechanisms assumed in the theory may affect the general predictions. An analysis of our data presented in chapter 4 reveals that submerged vegetation has similar overall effects on water clarity across our climatic gradient. Nonetheless, the results hint at differences in the underlying mechanisms between climate zones. For example, the data suggest that the positive effect of vegetation on top-down control of phytoplankton by zooplankton is lost at high densities of fish that are often found in warmer regions. The main factor explaining differences in the water clearing effect of vegetation among lakes in our data set was the concentration of humic substances. In lakes with a high concentration of humic substances vegetation did not enhance the water clarity.
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