Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    '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.

    We have a manual that explains all the features 

Current refinement(s):

Records 1 - 20 / 92

  • help
  • print

    Print search results

  • export

    Export search results

  • alert
    We will mail you new results for this query: keywords==mineralisatie
Check title to add to marked list
Simulation nitrogen-limited crop growth with SWAP/WOFOST : process descriptions and user manual
Groenendijk, Piet ; Boogaard, Hendrik ; Heinen, Marius ; Kroes, J.G. ; Supit, Iwan ; Wit, Allard de - \ 2016
Wageningen : Wageningen Environmental Research (Wageningen Environmental Research rapport 2721) - 59
crops - growth - soil - nitrogen - organic matter - mineralization - leaching - simulation models - nitrates - gewassen - groei - bodem - stikstof - organische stof - mineralisatie - uitspoelen - simulatiemodellen - nitraten
This report describes a soil nitrogen module (Soil-N), which is combined with the agro-hydrological model, SWAP, and the crop growth model, WOFOST. The core of the Soil-N module is a description of the nitrogen cycle, which is coupled to the organic matter cycle based upon the RothC-26.3 model. Nitrogen can be supplied to the soil as different types of fertilizer applications and through mineralisation of organic nitrogen. Ammonium and nitrate balances are calculated including uptake by plant roots, de-nitrification and leaching of nitrate. Data exchange is on a daily base. The partitioning of nitrogen within crops and the nitrogen contents of crop residues are calculated by WOFOST and passed to the Soil-N module. SWAP generates the data for establishing the water balance of the soil compartment for which the Soil-N perform the simulations. Nitrogen uptake by the crop is calculated as the minimum of the demand by the crop and the availability of nitrogen in the soil. The crop production rate is reduced when the mineral nitrogen stock is limited. Nitrogen-fixation is based on a simple approach. An improved sub-model for phenological stages of soybean was implemented. Increasing atmospheric CO2 concentrations can be accounted for. The innovated integrated model was tested using data sets from The Netherlands, China and Argentina, for which examples are given. This new model can be used as a tool in studies, in which both water and nitrogen can be limited for crop growth.
Stikstofkringloop in kalkrijke en kalkarme duinbodems : en de implicaties daarvan voor de effectiviteit van plaggen
Kooijman, A.M. ; Bloem, J. ; Cerli, C. ; Jagers Op Akkerhuis, G.A.J.M. ; Kalbitz, K. ; Dimmers, W.J. ; Vos, A. ; Peest, A.K. ; Kemmers, R.H. - \ 2014
Driebergen : Vereniging van Bos- en Natuurterreineigenaren (OBN rapport 2014/OBN189-DK) - 87
duingebieden - bodemchemie - stikstof - mineralisatie - ecologisch herstel - plaggen steken - natura 2000 - duneland - soil chemistry - nitrogen - mineralization - ecological restoration - sod cutting
In dit rapport staat het Natura 2000 habitattype H2130, de Grijze duinen, centraal. In veel duingebieden is de hoge stikstof-depositie een probleem voor een gunstige staat van instandhouding van de Grijze duinen. In de herstelstrategie die binnen de Programmatische Aanpak Stikstof (PAS) is uitgewerkt voor dit habitattype, staat o.a. de maatregel plaggen genoemd. In deze rapportage wordt onderzocht of plaggen de Grijze duinen minder gevoelig maakt voor stikstofdepositie en daarmee of deze maatregel effectief is. Voor het beheer van grijze duinen is het belangrijk meer inzicht te krijgen in de betekenis van N-opslag in de bodem en de rol van het bodemleven daarbij. Het in dit rapport beschreven onderzoek geeft antwoord op de vraag in welke mate micro-organismen en mesofauna, en uiteindelijk de opslag van N in organische stof in de bodem, een rol speelt bij de gevoeligheid van duinen voor N-depositie.
Organische stofbalans Excel-applicatie : onderdeel van het project sturen van de N-mineralisatie met kennis over organische stof
Zwart, K.B. ; Kikkert, A. ; Wolfs, A. ; Termorshuizen, A. ; Burgt, A. van der - \ 2013
Kennisakker.nl 2013 (2013)17 juli.
organische stof - berekening - bodembeheer - stikstof - mineralisatie - bodemvruchtbaarheid - akkerbouw - organic matter - calculation - soil management - nitrogen - mineralization - soil fertility - arable farming
In opdracht van Productschap Akkerbouw is door het Louis Bolk Instituut, BLGG AgroXpertus, Alterra en HLB een applicatie ontwikkeld die snel en eenvoudig per teeltrotatie de OS-balans en stikstofmineralisatie in beeld brengt.
Sturen van de N-mineralisatie met kennis over organische stof
Zwart, K.B. ; Wolfs, A. ; Kikkert, A. ; Termorshuizen, A. ; Burgt, G.J.H.M. van der - \ 2013
Wijster : HLB - 11
organische stof - stikstof - mineralisatie - bodemvruchtbaarheid - berekening - bemesting - bodembeheer - akkerbouw - organic matter - nitrogen - mineralization - soil fertility - calculation - fertilizer application - soil management - arable farming
Stikstoflevering vanuit organische stof (OS) wordt belangrijker naarmate de bemestingsnormen strakker worden. Dit project kent drie fasen met de volgende doelen. Fase I: de bestaande kennis over organische stof en stikstofmineralisatie te ontsluiten voor zowel telers als voorlichters, Fase II: een functioneel ontwerp van een adviesmodule op te leveren waarmee de stikstofbenutting vanuit de bodem kan worden gekwantificeerd bij diverse managementmaatregelen rond organische stof. Gedurende het project is besloten om dit te wijzigen in een werkende module. Fase III: de opgeleverde adviesmodule te testen in de praktijk op een viertal locaties en te demonstreren op een 20-tal praktijkbedrijven.
De organische stof balans met de te verwachten stikstoflevering per teeltrotatie : opzet en gebruikswijze van een rekenmodule
Zwart, K.B. ; Wolfs, A. ; Kikkert, A. ; Termorshuizen, A. ; Burgt, G.J.H.M. van der - \ 2013
Wijster : HLB - 17
organische stof - stikstof - mineralisatie - berekening - bodembeheer - bodemvruchtbaarheid - akkerbouw - organic matter - nitrogen - mineralization - calculation - soil management - soil fertility - arable farming
Organische stof speelt een hoofdrol in de vruchtbaarheid van de bodem. In opdracht van Productschap Akkerbouw is door het Louis Bolk Instituut, BLGG AgroXpertus, Alterra en HLB een applicatie ontwikkeld die snel en eenvoudig per teeltrotatie de organische stofbalans en stikstofmineralisatie in beeld brengt. In dit rapport wordt de opzet en de gebruikswijze van de applicatie kort uiteengezet.
Sturen van de N-mineralisatie met kennis over organische stof
Zwart, K.B. ; Kikkert, A. ; Wolfs, A. ; Termorshuizen, A. ; Burgt, G.J.H.M. van der - \ 2013
Kennisakker.nl 2013 (2013)18 juli.
akkerbouw - bemesting - stikstof - mineralisatie - organische stof - arable farming - fertilizer application - nitrogen - mineralization - organic matter
Doordat gebruiksnormen de maximale bemesting met stikstof bepalen, wordt het steeds belangrijker om goed te kunnen voorspellen hoeveel stikstof de bodem levert. Wanneer de voorspelbaarheid hoog is, kan maximaal rekening worden gehouden met de levering van stikstof uit de bodem, wat kosten bespaart en uitspoeling van N reduceert.
Soil biota and nitrogen cycling in production grasslands with different fertilisation histories
Rashid, M.I. - \ 2013
University. Promotor(en): Lijbert Brussaard, co-promotor(en): Egbert Lantinga; Ron de Goede. - S.l. : s.n. - ISBN 9789461735485 - 192
stikstofkringloop - bodemfauna - mineralisatie - rundveemest - decompositie - bodeminvertebraten - bodem ph - aardwormen - graslanden - bodembiologie - nitrogen cycle - soil fauna - mineralization - cattle manure - decomposition - soil invertebrates - soil ph - earthworms - grasslands - soil biology
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)
Decomposition rate of organic fertilizers: effect on yield, nitrogen availability and nitrogen stock in the soil
Opheusden, A.H.M. van; Burgt, G.J.H.M. van der; Rietberg, P.I. - \ 2012
Driebergen : Louis Bolk Instituut (Publicatie / Louis Bolk Instituut 2012-033 LbP) - 40 p.
organische meststoffen - bodemchemie - akkerbouw - mineralisatie - biologische landbouw - stikstof - bodem-plant relaties - opbrengsten - oostelijk flevoland - bemesting - organic fertilizers - soil chemistry - arable farming - mineralization - organic farming - nitrogen - soil plant relationships - yields - fertilizer application
The nitrogen of organic fertilizers does not fully mineralize within a season, and hence will partly become available in later years. This effect is taken into account for the first year but generally not in later fertilizer applications. If it would be taken into account, fertilizer use could be more efficient. This study is an analysis of a 13-year field trial where crop yield was measured in 13 fertilizer treatments which differ in total N applied and decomposition rate. This is complemented with a model study in which mineralization and soil nitrogen content were calculated.
Hoe meet je bodemkwaliteit?
Thoden, T.C. ; Haan, J.J. de - \ 2012
PPO AGV
bodembiologie - bodemkwaliteit - mineralisatie - bodemweerbaarheid - monitoring - indicatoren - akkerbouw - soil biology - soil quality - mineralization - soil suppressiveness - indicators - arable farming
Poster met onderzoeksinformatie. In de veldproeven wordt gekeken welke bodemindicatoren goede inzichten geven in de bodemkwaliteit en in de effecten van maatregelen op de bodemkwaliteit. Zo proberen de onderzoekers tot een kleine effectieve set bodemindicatoren te komen die betaalbaar en in de praktijk toepasbaar is.
Stikstofwerking van mineralenconcentraten : stikstofwerkingscoëfficiënten en verliezen door denitrificatie en stikstofimmobilisatie bepaald onder gecontroleerde omstandigheden
Ehlert, P.A.I. ; Nelemans, J.A. ; Velthof, G.L. - \ 2012
Wageningen : Alterra (Alterra-rapport 2314) - 98
kunstmeststoffen - omgekeerde osmose - dierlijke meststoffen - experimenteel veldonderzoek - proefopzet - stikstof - mineralisatie - fertilizers - reverse osmosis - animal manures - field experimentation - experimental design - nitrogen - mineralization
Vervaardiging van mineralenconcentraten uit de dunne fractie van dierlijke mest met omgekeerde osmose biedt perspectief om stikstof uit mest beter te benutten. In veldonderzoek werd vastgesteld dat de stikstofwerkingscoëfficiënt van mineralenconcentraten lager is dan 100% ten opzichte van kalkammonsalpeter. Mogelijke oorzaken voor deze lagere werking werden onderzocht. Onder geconditioneerde omstandigheden van potproeven en incubatieproeven blijken mineralenconcentraten de werking van kalkammonsalpeter te kunnen benaderen; stikstofwerkingscoëfficiënten ten opzichte van kalkammonsalpeter van 78-98% werden vastgesteld met gras en snijbiet als testgewas. Mineralenconcentraten hebben een hogere stikstofwerkingscoëfficiënt dan onbewerkte varkensdrijfmest die ten opzichte van kalkammonsalpeter 64-77% werking vertoonde. Mineralenconcentraten bevatten naast ammoniumstikstof en kalium ook organische stof en organisch gebonden stikstof. De aanwezigheid van organische stof en organische stikstof verlaagt de stikstofwerking. Bij zandgrond werden hogere werkingscoëfficiënten vastgesteld dan op kleigrond. Gras benut stikstof uit mineralenconcentraten efficiënter dan snijbiet. Mineralenconcentraten blijken onder strikt anaerobe omstandigheden de denitrificatie sterk te verhogen. Stikstofimmobilisatie is geen duidelijk aanwijsbare oorzaak voor een lagere werkingscoëfficiënt. Denitrificatie en het aandeel organisch gebonden stikstof zijn belangrijke factoren die de stikstofwerkingscoëfficiënt bepalen.
Bioscorodite: biological crystallization of scorodite for arsenic removal
Gonzalez-Contreras, P.A. - \ 2012
University. Promotor(en): Cees Buisman, co-promotor(en): Jan Weijma. - S.l. : s.n. - ISBN 9789461732941 - 206
arsenaten - ferri-ionen - kristallisatie - mineralisatie - metallurgie - afvalverwerking - arsenates - ferric ions - crystallization - mineralization - metallurgy - waste treatment

The use of arsenic is banned for most applications, leading to its accumulation as arsenic trioxide and ferric arsenate sludge. The aim of this thesis was to develop a controlled process for biological crystallization of scorodite from metallurgical streams. In this thesis, the proof of principle, reactor selection and operational conditions of bioscorodite crystallization were studied. The results from this thesis resulted in the ARSENOTEQTM process, currently commercialized by Paques B.V. (Balk, The Netherlands).
The bioscorodite process in practice occurs in a continuous airlift reactor at pH < 2 and 70°C in a single step. Produced bioscorodite crystals resemble very well the scorodite mineral in their arsenic content and structural water content. The most stable crystals can be easily harvested by sedimentation from the bioreactor due to their larger sizes. Bioscorodite crystals were classified as non-hazardous material. This makes the bioscorodite sludge very suitable for long-term arsenic safe disposal.

Opbrengstvergelijking percelen Nutriënten Waterproof en praktijkpercelen
Geel, W.C.A. van; Verstegen, H.A.G. ; Haan, J.J. de - \ 2011
Lelystad : PPO AGV (PPO Projectrapport 428) - 36
akkerbouw - bemesting - emissie - oppervlaktewater - grondwater - mineralisatie - bodemchemie - zandgronden - midden-limburg - proefbedrijven - arable farming - fertilizer application - emission - surface water - groundwater - mineralization - soil chemistry - sandy soils - pilot farms
Van 2005 t/m 2008 is op de BSO-percelen het project Nutriënten Waterproof (NWP) uitgevoerd. Dit project richtte zich op het ontwikkelen van bedrijfssystemen met een minimale emissie van nutriënten naar het grond- en oppervlaktewater. In NWP zijn, naast een biologisch systeem, twee geïntegreerde bedrijfssystemen vergeleken: 1. GI-Hoog: voldoende aanvoer van organische stof naar de bodem, op peil houden van de bodemmineralisatie en fosfaatevenwichtsbemesting (fosfaataanvoer gelijk aan fosfaatafvoer); 2. GI-Laag: verlagen bodemmineralisatie door minimale aanvoer van organische stof en versnelde afname van de fosfaatvoorraad in de bodem door minder fosfaat aan te voeren dan er wordt afgevoerd.
Predicting soil nitrogen supply : relevance of extractable soil organic matter fractions
Ros, G.H. - \ 2011
University. Promotor(en): Willem van Riemsdijk, co-promotor(en): Erwin Temminghoff; Ellis Hoffland. - [S.l.] : S.n. - ISBN 9789085858829 - 243
mineralisatie - organische stikstof - bodem - organisch bodemmateriaal - bodemonderzoek - voorspelling - bodemtestwaarden - beoordeling - oogstresten - mineralization - organic nitrogen - soil - soil organic matter - soil testing - prediction - soil test values - assessment - crop residues

Predicting the potential of soils to supply N is of considerable importance to maximize agricultural N use efficiency and to minimize environmental losses. This research examines and evaluates the current soil testing approach, which uses extractable organic N (EON) fractions to predict soil N supply, using isotopic 15N tracing, multivariate statistics and meta-analytical techniques.
Almost all 20 EON fractions that have been developed during recent decades significantly reflect the potential of soils to supply N, in spite of the strong differences in size and composition of EON due to extraction methodology. The EON fractions have therefore been considered as highly bio-available N pools in soil. However, most of them performed either worse than or similarly to total N as predictor of soil N supply, and the uncertainty of the predicted soil N supply (even under controlled environmental conditions) is still too big for serious improvement of fertilizer management.
A micro-diffusion method is developed to estimate gross EON fluxes in order to investigate the biochemical basis for observed relationships between EON and soil N supply. The fate of EON fractions in N mineralization, in particular those fractions that are obtained with weak hydrolyzing salt solutions, is comparable to that of dissolved organic N (DON). Both DON and EON can be considered as (intermediate) decomposition waste products in an abiotic and biotic controlled equilibrium with total N.
Therefore, their relationship with soil N supply likely reflect that both DON, EON, and soil N supply are mutually dependent on total N.
The dependency of soil N supply on methodological and environmental issues strongly encourages more effort to be put into validation and up-scaling, particularly regarding the quantification of the differences between laboratory and field experiments. A combination of soil testing with simulation modeling is necessary to account for the numerous environmental factors controlling soil N supply. The exact EON fraction that can be used in such an approach is less important and practical considerations may be decisive to select one for routine application in soil analysis.
In conclusion, a holistic approach, which considers spatial and temporal variability of both soil N supply and crop N demand, may provide a successful approach to improving fertilizer management at the farm-scale.

Betere benutting van stikstof uit vanggewassen, thema: duurzame mineralen BO-12.03-002-002
Verhoeven, J.T.W. ; Geel, W.C.A. van; Schooten, H.A. van - \ 2011
S.n.
ondergewassen - zandgronden - veldproeven - stikstof - mineralisatie - catch crops - sandy soils - field tests - nitrogen - mineralization
Poster met onderzoeksinformatie. Doel van het onderzoek is om het juiste inwerkmoment in het voorjaar op zandgrond vast te stellen, om het vrijkomen van stikstof uit een winterhard vanggewas aan te laten sluiten bij het opnamepatroon van het volggewas snijmaïs.
Understanding the diverse roles of soil organic matter in the cereal - Striga hermontica interaction
Ayongwa, G.C. - \ 2011
University. Promotor(en): Thomas Kuijper, co-promotor(en): Tjeerd-Jan Stomph. - S.l. : s.n. - ISBN 9789085858430 - 131
striga hermonthica - sorghum bicolor - parasitaire onkruiden - organisch bodemmateriaal - bodemvruchtbaarheid - experimenteel veldonderzoek - stikstof - mineralisatie - beperkingen - gewasproductie - kameroen - nigeria - parasitic weeds - soil organic matter - soil fertility - field experimentation - nitrogen - mineralization - constraints - crop production - cameroon

Keywords: Striga hermonthica, Sorghum bicolor, soil fertility, organic matter, N-mineralisation, farmers’ priority, production constraints, intensification.


The problem of the parasitic weed striga (Striga hermonthica (Del.) Benth.) has worsened for African farmers, in conjunction with degrading soil fertility. An analysis of the striga problem showed that scientists, policy makers and farmers conceptualise striga differently. Whether striga is viewed as a weed or a symptom of degraded soils raises two questions: Should farmers control striga, even when the impact on yields would be negligible? Or should fertility enhancement, leading to higher yields, be their focus, even when not accompanied by an immediate reduction in striga? This study seeks to understand how organic matter inputs affect nutrient dynamics, sorghum (Sorghum bicolor [L.] Moench) production and striga abundance.
Surveys in northern Cameroon showed that striga infestation increased over the past two decades. Increased land pressure led to reduced fallow periods and enhanced cereal (mono-) cropping. Reduced access to fertiliser and manure hampered options to improve soil fertility. Yields from farmers’ fields did not correlate with striga incidence, confirming farmers’ prioritisation of soil fertility, weeds, and labour as production constraints, rather than striga. The entry point to tackle low yields and the worsening of the striga situation should follow farmers’ priority of alleviating low soil fertility.
Whether and how soil fertility improvement, through organic matter, enhances agricultural productivity and reduces striga, was investigated in field experiments. Organic matter amendments significantly depressed striga seed survival, with the strongest effect achieved at higher quality; presumably due to higher microbial activity. Organic matter enhanced soil water retention and soil temperature but without effects on striga seed survival. Organic matter did not affect soil ethylene concentrations. The effect of organic matter amendments was directly related to N mineralisation, both for better cereal growth and reduced striga survival. The organic matter amendments and use of fallow, as applied here, however, may not be practicable for the resource-poor farmer.
Increasing N-fertilisation increased sorghum root N mass concentration, which resulted in a lower striga seed germination. That relationship was linear up to a root N mass concentration of 19.5 mg g-1 where seed germination was close to but always still above 0%.
In a broader framework of the research findings, the ultimate solution for farm productivity for Africa is in sustainable farm intensification by investing in soil fertility. However, the prevailing land tenure system and limited access to fertiliser and organic matter need to be overcome. A new conceptual model is proposed, indicating how changes in both cereal yield and striga infestation over time co-vary with changes in soil fertility. The implication of this model is that recovery of soil fertility should be the priority. The challenge to agronomists remains to consider how to make farm intensification rewarding and attainable for resource-poor farmers. In areas where striga is an obstacle, an integrated scheme for the intensification of cereal cropping should start with integrated soil fertility management. Crop rotation and intercropping with selected non-host leguminous crops are essential ingredients.

Inwerktijdstip van winterharde vanggewassen : deskstudie
Geel, W.C.A. van; Schooten, H.A. van; Verhoeven, J.T.W. - \ 2010
Lelystad : PPO AGV - 31
groenbemesters - ondergewassen - mineralisatie - verhoudingen - koolstof - stikstof - green manures - catch crops - mineralization - ratios - carbon - nitrogen
Het telen van een onbemeste groenbemester als stikstofvanggewas na de hoofdteelt, is een na-oogst-maatregel die de nitraatuitspoeling kan verminderen. Het vanggewas neemt de reststikstof op uit de bodem, die is achtergelaten door het hoofdgewas en de stikstof die in de nazomer en herfst mineraliseert. Het optimale inwerktijdstip in het voorjaar hangt (naast weersinvloed) mede af van het N-gehalte in de droge stof c.q. de C/N-verhouding. Bij een hoog N-gehalte (lage C/N-verhouding) mineraliseert de stikstof na inwerken sneller dan bij een laag N-gehalte (hoge C/N-verhouding) en ligt het optimale inwerktijdstip waarschijnlijk later. Het verdient aanbeveling om de relatie tussen optimaal inwerktijdstip in het voorjaar en C/N-verhouding nader te bestuderen in het uit te voeren veldonderzoek
Laboratory experiments testing the effectiveness of the commercially available product PoCo in mitigating cyanobacterial blooms and decomposing organic matter
Lürling, M.F.L.L.W. ; Kosten, S. - \ 2009
Wageningen : Wageningen University (Aquatic Ecology Memo reports M349) - 17
waterverontreiniging - cyanobacteriën - meren - katalysatoren - tests - eutrofiëring - mineralisatie - daphnia - paraguay - waterzuivering - biokatalyse - ecologisch herstel - water pollution - cyanobacteria - lakes - catalysts - eutrophication - mineralization - water treatment - biocatalysis - ecological restoration
The Dutch company WiseUse International BV has proposed using a so-called bio stimulator “PoCo” (Pollution Control) in ecological restoration of Lake Ypacarai (Paraguay). In this study results of laboratory assays are reported testing the performance of PoCo regarding the alleged enhanced mineralization of organic matter in the water phase and sediment, the inhibition of cyanobacterial growth (as a clear measure counter acting the symptoms of eutrophication) and effects on survival of the waterflea Daphnia.
Soil biodiversity and nitrogen cycling under agricultural (de-)intensification
Postma-Blaauw, M.B. - \ 2008
University. Promotor(en): Lijbert Brussaard, co-promotor(en): Ron de Goede; Jaap Bloem; Jack Faber. - [S.l.] : S.n. - ISBN 9789085048909 - 198
bodemfauna - biodiversiteit - aardwormen - nematoda - stikstof - kringlopen - intensivering - mineralisatie - agrarische bedrijfsvoering - nederland - bodembiodiversiteit - agro-ecosystemen - agrobiodiversiteit - soil fauna - biodiversity - earthworms - nitrogen - cycling - intensification - mineralization - farm management - netherlands - soil biodiversity - agroecosystems - agro-biodiversity
Bodemorganismen spelen een sleutelrol in de recycling van nutriënten door hun bijdrage aan de afbraak van organisch materiaal (decompositie), het beschikbaar maken van voedingstoffen (mineralisatie) die benut kunnen worden voor plantengroei en bioturbatie van de bodem. In de intensieve landbouw wordt deze rol ten dele overgenomen door het gebruik van kunstmest en grondbewerking. Deze landbouwpraktijken hebben het nadelige gevolg dat onder andere de diversiteit aan bodemorganismen afneemt, en nutrientenverliezen, met name stikstof, naar het milieu toenemen. Daarom hebben wetenschappers zich recentelijk in toenemende mate gericht op het creëren en ondersteunen van vormen van landbouw die op de lange termijn duurzaam zijn. Een efficiëntere benutting van nutrienten in agro-ecosystemen kan wellicht bereikt worden wanneer de bodemgemeenschap een grotere rol in de nutriëntencyclus gaat spelen.
Mineralisatie van mest en organische stof in de bodem : een indicator op basis van (bio) chemische parameters
Zwart, K.B. - \ 2007
Wageningen : Alterra (Alterra-rapport 1504) - 49
bodemchemie - mineralisatie - dierlijke meststoffen - graslanden - organisch bodemmateriaal - indicatoren - nederland - bodemkwaliteit - soil chemistry - mineralization - animal manures - grasslands - soil organic matter - indicators - netherlands - soil quality
Van zes verschillende bemestingsregimes bij grasland is onderzocht wat het effect is op de bodemsamenstelling in de mineralisatie. Verder is voor uiteenlopende bodems van vijf verschillende bodemparameters de geschiktheid als mineralisatie indicator onderzocht. Na drie jaar was er geen verschil in het totaal C of totaal N gehalte tussen niet en wel bemeste veldjes
Check title to add to marked list
<< previous | next >>

Show 20 50 100 records per page

 
Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.