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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Prevalence of dental disorders in degus and evaluation of diagnostic methods to determine dental disease and its prognosis
Bolhuis, Hester van; Hoffen, Lotte van; Zijll Langhout, Martine van; Engeldorp Gastelaars, Heleen van; Hendriks, Wouter ; Lamberts, Marnix ; Kik, Marja - \ 2017
Veterinary Record 181 (2017)23. - ISSN 0042-4900
apical elongation - calcium - malocclusion - octodon degus - phosphorus - radiography
Degus (Octodon degus) are prone to develop dental disease with deleterious health effects. The two studies reported here aimed to determine the prevalence of dental disorders in degus and to identify and evaluate diagnostic tools for determination of prognosis of these disorders. In study A, health data from 225 degus at AAP, Rescue Center for Exotic Animals in the Netherlands, were collated and the prevalence of dental disorders and differences in sex and age at clinical onset of symptoms associated with dental disorders were described. The prevalence was 34.7 per cent and higher (P<0.01) in males than in females. The occurrence of cheek teeth malocclusion was highly positively (P<0.0001) correlated to mortality. In study B, 36 skulls were examined by macroscopic evaluation, radiography and histology. Additionally, the calcium:phosphorus (Ca:P) of mandibular bone in degus with and without dental disorders were determined. There was no significant (P=0.10) difference in Ca:P between the two groups. Quantifying mandibular apical cheek teeth elongation via macroscopic evaluation was highly correlated (P<0.01) to the results obtained via radiography. Examination for apical elongation by palpation and diagnostic imaging should be included in routine health monitoring of degus. Apical elongation appeared to develop before coronal elongation and when cheek teeth malocclusion occurred, prognosis for recovery of dental disease was poor.
Fosforbenutting bij biologisch gehouden vleesvarkens
Bikker, Paul ; Tije, Naomi ten; Tijkorte, Achim - \ 2017
Wageningen : Wageningen Livestock Research (Wageningen Livestock Research rapport 1069) - 22
varkenshouderij - biologische landbouw - fosfor - varkensvoeding - slachtdieren - proeven - proefopzet - pig farming - organic farming - phosphorus - pig feeding - meat animals - trials - experimental design
Dit rapport beschrijft een praktijkstudie naar de mogelijkheden om het verteerbaar fosfor (vP) gehalte in het rantsoen van biologisch gehouden vleesvarkens te verlagen. De verlaging van het berekend vP-gehalte met 0,4 g/kg (15% in startvoer, 20% in vleesvarkensvoer) had geen negatieve invloed op de gezondheid en groei van de varkens. Deze verlaging ten opzichte van het controlevoer draagt bij aan een hogere fosforbenutting. De gerealiseerde vP-gehalten, gebaseerd op analyse van voer en feces, waren echter aanzienlijk hoger dan vooraf berekend op basis van tabelwaarden. Hierdoor kan niet vastgesteld worden of een verlaging van het vP-gehalte ten opzichte van de norm voor regulier gehouden varkens mogelijk is zonder invloed op de dierprestaties.
Efficiency of phosphorus resource use in Africa as defined by soil chemistry and the impact on crop production
Magnone, Daniel ; Bouwman, Alexander F. ; Zee, Sjoerd E.A.T.M. Van Der; Sattari, Sheida Z. ; Beusen, Arthur H.W. ; Niasar, Vahid J. - \ 2017
Energy Procedia 123 (2017). - ISSN 1876-6102 - p. 97 - 104.
DPPS - modelling - phosphorus - soil - soil resources
By 2050 the global population will be 9.7 billion, placing an unprecedented burden on the world's soils to produce extremely high food yields. Phosphorus (P) is crucial to plant growth and mineral fertilizer is added to soil to maintain P concentrations, however this is a finite resource, thus efficient use is critical. Plants primarily uptake P from a labile (available) P pool and not from the stable solid phase; transfer between these pools limits bioavailability. Transfer is controlled by soil properties which vary between soil types. The dynamic phosphorus pool simulator (DPPS) quantifies crop production and soil P relationships by utilising the transfer. This approach effectively models crop uptake from soil inputs, but it does not quantify the efficiency use. This study incorporates geochemical techniques within DPPS to quantify the efficiency of fertilizer-P use based on soil chemistry.
Bepaling samenstelling van vaste mest met NIRS
Rietra, R.P.J.J. ; Oenema, O. - \ 2017
Wageningen : Wageningen Environmental Research (Wageningen Environmental Research rapport 2837) - 27
dierlijke meststoffen - stikstof - fosfor - nabij infrarood spectroscopie - referentienormen - analyse - betrouwbaarheid - analytische methoden - animal manures - nitrogen - phosphorus - near infrared spectroscopy - reference standards - analysis - reliability - analytical methods
From harmful to useful algae
Blaas, Harry - \ 2017
University. Promotor(en): Carolien Kroeze. - Wageningen : Wageningen University - ISBN 9789463430357 - 117
algae - algae culture - adverse effects - nitrogen - phosphorus - rivers - eutrophication - waste water treatment - europe - algen - algenteelt - nadelige gevolgen - stikstof - fosfor - rivieren - eutrofiëring - afvalwaterbehandeling - europa

Eutrophication of coastal waters is a worldwide phenomenon. This study focuses on eutrophication in the coastal waters of Europe. Eutrophication is mainly a result of the increased transport of nutrients from watersheds by rivers to the coastal waters. Nutrient losses from watersheds are generally from agriculture, sewage, atmospheric deposition and from natural sources. In case of an overload of nutrients in the coastal waters, algal blooms may develop which increase the risk of hypoxia, fish mortality, and loss of biodiversity.

Algae can also be useful. They are increasingly considered an interesting product. For instance, micro-algae can be grow on land to produce proteins, lipids and fatty acids. Some studies indicate that micro-algae can be an important feedstock in the future for, for instance, the production of biodiesel. Moreover, macro-algae can be produced in seawater in sea farms. Macro-algae can be edible, or be used as a feedstock. By yielding macro-algae, nutrients are removed from the water, reducing coastal eutrophication.

The objective of this study is to analyse past and future trends in nutrient export by rivers to European seas with a focus on the role of algae. Three types of algae will be distinguished: (1) harmful algal blooms in coastal seas, (2) cultivation of micro-algae on land for the production of proteins, lipids and fatty acids, and (3) cultivation of multi cellular algae in seaweed farms for human consumption or other products.

To meet the objective the following research questions are addressed:

RQ1 To what extent do N and P loads exceed levels that minimize the risk of harmful algal blooms, and what are the relative shares of sources of N and P in rivers of the European Union?

RQ2 What are the potential consequences of large-scale land-based production of biodiesel from cultivated micro-algae in Europe for coastal eutrophication?

RQ3 Would it possible to cultivate and process micro-algae in a factory, and what is the environmental performance?

RQ4 To what extent can seaweed farming in combination with nutrient management in agriculture and waste water treatment reduce the potential for coastal eutrophication?

These questions are answered through model analyses. The Global NEWS (Nutrient Export from WaterSheds) model simulates river export of nutrients as function of human activities on land. It includes more than 6000 rivers worldwide. It can be used to quantify nutrient flows from land to sea for the years 1970, 2000, 2030 and 2050. For future years four scenarios have been implemented. One of these scenarios is named Global Orchestration and mostly used as a reference in this thesis. This scenario assumes a globalised world, with a reactive approach towards environmental problems. The model was released in 2010, has been validated for the years 1970 and 2000. The nutrients considered in the model are nitrogen (N) and phosphorus (P). In this thesis Global NEWS is used to calculate transport of nutrients to the coastal waters of Europe. The model uses ICEP (Indicator for Coastal Eutrophication Potential) values at the river mouths as an indicator for potentially harmful effects of nutrient enrichment. These ICEP values reflect the ratio of nitrogen and phosphorus to silica in coastal seas. A positive ICEP value indicates that nitrogen or phosphorus levels are too high, favouring conditions for potentially harmful algae to bloom.

In chapter 2 Global NEWS is used to calculate the transport of nutrients and ICEP values for 48 European rivers for the years 2000 and 2050. The model calculates a positive ICEP for 38 rivers in the year 2000, and for 34 rivers in the year 2050. This indicates that current policies are not so effective in reducing the river transport of nutrients. For polluted rivers the anthropogenic sources of the nutrients are investigated. For most rivers the dominant polluting sources are agriculture or sewage. The results indicate that a basin-specific policy is needed to reduce the risks of coastal eutrophication.

In chapter 3 the focus is on useful algae: micro-algae cultivation on land for, for instance, biodiesel production. The consequences of large-scale production of biodiesel on nutrient export by rivers to the European coastal waters are investigated. A scenario is developed assuming that a production of 0.4 billion m3 diesel from cultivated micro-algae. The cultivation is assumed to be in the open air, for instance in ponds or in closed tube systems. Such production levels would need a land surface area as large as Portugal. The Global NEWS model is used to calculate the amount of waste water from micro-algae production that will be transported to the coastal waters in this scenario. The results indicate that large-scale cultivation of micro-algae on land can become a source of nutrient pollution in rivers. In the scenario with large-scale micro-algae cultivation the future transport of nitrogen and phosphorus is considerably higher than in the reference scenario. To ensure sustainable production of biodiesel from micro-algae it is important to develop cultivation systems with low nutrient losses to the environment.

Chapter 4 presents a design of a factory for the cultivation and processing of micro-algae in an environmentally sound way. The factory does not use fossil fuels and applies maximum recycling of water and nutrients. In this factory it is possible to produce lipids, carbohydrates, proteins and minerals. The factory can be built on any piece of land, so there is no need to use arable land. The factory is independent of weather and climate. Energy can be delivered by wind mills. In this chapter an example of producing diesel in the factory is shown. In the 12 stories factory with a cultivation area of 1 hectare, 810 ton micro-algae can be cultivated per year. This is enough for the production of 386 ton diesel per year.

Chapter 5 focuses on mitigation of eutrophication in European coastal waters. A scenario is presented assuming different types of measures. The scenario first assumes that nutrient use efficiencies in agriculture are higher than today, and that waste water treatment in sewage systems is improved. In addition, it assumes that all excess N and P in coastal waters is harvested in seaweed farms producing edible macro-algae. In our scenario for 2050 there is seaweed farming in the coastal waters of 34 rivers mouths in Europe .NEWS The areas needed to ensure that ICEP values remain below 0 (low potential for coastal eutrophication) range between 0 and 952 km2 per river mouth.

This thesis shows that algae can be both harmful and useful. River export of nutrients can lead to coastal eutrophication increasing the risks of harmful algal blooms. On the other hand, micro-algae can be produced without environmental harm on land, and macro-algae can be useful in reducing pollution levels in coastal seas. This thesis could serve as a basis for environmental policies to stimulate the production of these useful algae. The methods to mitigate algal blooms and to use algae in a sustainable way in this thesis are also useful for other parts of the world.

Bronnen van nutriënten in het oppervlaktewater in het beheergebied van Wetterskip Fryslân : studie naar de herkomst en beïnvloedbaarheid van stikstof en fosfor in het oppervlaktewater voor zes polders in het beheergebied van Wetterskip Fryslân
Boekel, E.M.P.M. van; Groenendijk, P. ; Renaud, L.V. - \ 2016
Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2727) - 50 p.
oppervlaktewater - voedingsstoffen - stikstof - fosfor - modellen - oppervlaktewaterkwaliteit - mestbeleid - friesland - surface water - nutrients - nitrogen - phosphorus - models - surface water quality - manure policy
Om inzicht te krijgen in de herkomst en beïnvloedbaarheid van stikstof en fosfor in het oppervlaktewater in het beheergebied van Wetterskip Fryslân zijn met de ECHO-methodiek stofbalansen opgesteld voor een zestal polders. De beïnvloedbaarheid van bronnen is afgeleid conform de werkwijze die wordt toegepast door de Nutriëntenwerkgroep Rijn-West. Daarnaast is het effect van het mestbeleid op de nutriëntenbelasting van het oppervlaktewater in beeld gebracht op basis van uit het landelijke STONE-model afgeleide resultaten voor de uitspoeling bij gebruiksnormen van het 5e Nitraat Actieprogramma (5e NAP). Uit de resultaten blijkt dat het grootste deel (46 −74%) van de stikstof- en fosforbelasting van het oppervlaktewater afkomstig is van beïnvloedbare bronnen (actuele bemesting en nalevering bodem) met een effect op de korte en lange termijn. Bronnen met een direct effect (voornamelijk inlaatwater) dragen voor 5 − 45% bij aan de totale nutriëntenbelasting. De stikstofbelasting van het oppervlaktewater is voor 7 − 22% afkomstig van niet of moeilijk te beïnvloeden bronnen, voor fosfor ligt dit tussen 1 en 12%. Het doorrekenen van het mestbeleid (5e NAP) resulteert in een reductie van de uit- en afspoeling tussen 1,9 en 9,1%. Voor de totale nutriëntenbelasting ligt de reductie als gevolg van de maatregelen in het 5e NAP tussen 1,1 en 7,7%.
Variation in phosphorus acquisition efficiency among maize varieties as related to mycorrhizal functioning
Wang, X.X. - \ 2016
University. Promotor(en): Thomas Kuijper; Ellis Hoffland, co-promotor(en): G. Feng. - Wageningen : Wageningen University - ISBN 9789462577985 - 168 p.
zea mays - mycorrhizas - maize - phosphorus - nutrient use efficiency - vesicular arbuscular mycorrhizas - nutrient uptake - varieties - mycorrhizae - maïs - fosfor - nutriëntengebruiksefficiëntie - vesiculair-arbusculaire mycorrhizae - voedingsstoffenopname (planten) - rassen (planten)

Phosphorus (P) is a main limiting factor for agricultural production, but overusing P fertilizer has brought serious environmental damages in China. Improving P acquisition efficiency of agricultural crops is an urgent topic. It has been proven repeatedly that arbuscular mycorrhizal fungi (AMF) and genetic diversity within one crop plant can play important roles in P uptake by crops. The main objective of this thesis was to understand the role of the arbuscular mycorrhizal symbiosis in P acquisition efficiency of different maize varieties. The specific objectives were to test: 1) how P uptake by maize varieties responds to colonization by the native AMF community in the field; and 2) whether AMF hyphae take up P for plants from phytate which is the most abundant organic P form in soil; 3) whether mixing maize cultivars can improve maize productivity and whether AMF can play a role in this system; and 4) how AMF species (or community) legacy affects successional maize growth. In this thesis, I combined field experiments and greenhouse experiments and made use of maize genetic diversity and (native) AMF to improve P (including inorganic and organic P) acquisition.

The effects of one single AMF species on maize growth and nutrient uptake have been well studied, but how maize varieties respond to the native AMF community has been insufficiently studied. In Chapter 2, I focused on how maize varieties responded to the native AMF community by using rotated cores in the field, to compare mycorrhizal responsiveness among 20 maize varieties and the difference of the AMF native community of four maize varieties (two old landraces and two modern hybrids). The results indicated that, 1) increased P fertilizer significantly reduced mycorrhizal responsiveness in the field; 2) a complicated relationship exists between mycorrhizal responsiveness in the field and pot experiment; 3) there was no significant difference between old and modern maize varieties in terms of mycorrhizal responsiveness and colonization; 4) there were only small differences in AMF community composition among the four maize varieties. By comparing mycorrhizal responsiveness of maize varieties between in the pot experiment and in the field experiment (with in-growth cores), I found mycorrhizal responsiveness of maize varieties in the pot experiment was significantly larger than that in the field experiment. Thus, mycorrhizal responsiveness of varieties within one cereal plant species tested classically in pots may not present their realistically mycorrhizal responsiveness in field.

Phytate is the most abundant form of organic P in soil. To explore the potential of phytate utilization by plants is agriculturally and environmentally essential. Increased P nutrition of mycorrhizal plants derived from phytate has been reported, indicating that phytate can be a potential P source. However, earlier studies assessed phytate use by using acid phosphatase rather than phytase, and did not consider that phytate adsorption could lead to phosphate release. Thus, I investigated the effect of mycorrhizal hyphae-mediated phytase activity on P uptake by maize in Chapter 3. I conducted a rhizobox experiment to explore phytate use by mycorrhizal hyphae for two maize varieties. The results showed that: 1) phytate addition increased phytase and acid phosphatase activity, and resulted in increased P uptake and plant biomass; 2) the increase in P uptake and biomass were correlated with the increase of phytase activity but not with the increase of acid phosphatase activity; 3) lower phytate addition rate increased, but higher addition rates decreased hyphal length density. I conclude that P from phytate can be used by mycorrhizal plants, but that the phytate contribution to plant nutrition is likely limited. Phytase activity is a more relevant indicator to assess phytate use. In addition, there was a significant interaction between maize varieties and AMF species in taking up P from phytate, which implies there is a possibility to combine different maize varieties to increase total yield using phytate. Besides, I used an empirical relationship to assess phosphate release due to phytate addition. My calculation implies that phosphate desorption cannot be ignored when assessing phytate use, particularly when a large amount of phytate is applied as a P source.

In multispecies natural ecosystems, AMF can play a key role in enhancing plant productivity. However, their role in enhancing crop productivity in mixed cropping systems is still poorly understood. In Chapter 4, I conducted both greenhouse and field experiments to investigate whether mixing maize varieties with different P acquisition strategies could lead to overyielding, and what roles AMF play in this system with two maize varieties. The results showed that mixing maize varieties resulted in overyielding, both in P uptake and shoot biomass, but only when plants were mycorrhizal. At the same time, I found higher hyphal length density and higher AMF diversity in mixtures compared to the monocultures in the field experiment, and higher colonization rate and higher hyphal length density in mixtures in the pot experiment. Thus, I propose that overyielding by mixing maize varieties might be due to increased mycorrhizal performance leading to more P uptake. I also used the partitioning formula to calculate the contribution through the selection effect and complementarity effect to overyielding. I found that the increase of the total yield and P uptake in mixtures was largely due to complementarity effect, implying that relative overyielding and enhanced P uptake were not due to enhanced competitive ability by the larger variety. The results of Chapter 4 suggest that mixing mycorrhizal maize varieties might be beneficial for enhancing productivity and P uptake efficiency.

Plant - soil feedback experiments have shown that AMF can play a crucial role in determining the direction and magnitude of that feedback. Most studies investigated plant - soil feedback dynamics between different plant species. However, it is unknown to what extent one variety of an agricultural crop can affect the performance of another variety of that same crop through plant - soil feedback. In Chapter 5, I carried out a two-phase experiment in a greenhouse, including conditioning phase and test phase to determine plant - soil feedbacks in the absence and presence of AMF species or community, to test the effects of AMF on feedback dynamics. The results in Chapter 5 showed that: 1) in the conditioning phase, both maize varieties were differentially influenced by different AMF species compared to non-mycorrhizal control; 2) in the feedback phase, non-mycorrhizal maize exhibited negative feedback dynamics for biomass and P-uptake; 3) on the feedback phase, mycorrhizal maize generally exhibited positive feedback dynamics for biomass and P-uptake. The interaction coefficient was largest with the mixture of three different AMF species. The interaction coefficient for shoot and P uptake were significantly correlated with the coefficient for mycorrhizal colonization. These results imply that different maize varieties are affected differently by different AMF species, thereby influencing the productivity of the subsequent maize variety. The results also raise questions how AMF influence rhizosphere biota and how maize varieties may select more beneficial AMF.

In Chapter 6, I integrate the results from previous chapters. I discuss possible relationships between (negative) plant - soil feedback effect (due to pathogen) and the mycorrhizal effect on overyielding and improved P uptake due to mixing maize varieties (compared to the monoculture). I also discuss the linkage between phosphorus acquisition efficiency and mycorrhizal responsiveness within one crop species, and the relationship between plant genetic diversity and plant - soil feedback effects, and try to come up with a conceptual model how mixing maize varieties in the presence of AMF could be beneficial.

Response of broilers on incremental dietary P content and consequences for P- requirements
Krimpen, M.M. van; Dekker, R.A. ; Emous, R.A. van; Bikker, P. ; Bruininx, E.M.A.M. ; Lee, A.G. - \ 2016
Wageningen UR Livestock Research (Livestock Research report 931) - 44 p.
broilers - phosphorus - nutrient requirements - poultry feeding - broiler performance - feeds - poultry farming - vleeskuikens - fosfor - voedingsstoffenbehoeften - pluimveevoeding - vleeskuikenresultaten - voer - pluimveehouderij
The aim of the current experiment was to determine the aP requirements in modern broilers by performing a dose-response experiment. This study showed that for realizing maximal performance, in phase 1 (d1-d10) 5.4 g aP per kg of feed was required, in phase 2 (d11-d21) 4.3 g aP per kg of feed, and in phase 4 (d31-d38) 2.6 g aP per kg of feed. In phase 3 (d22-d30), performance of the broilers was not affected by dietary aP content. For realizing maximal tibia ash content in phase 3, an aP-level of 3.8 g/kg was required.
Fosfaatbenutting met groenbemesters bij een lage P-toestand van twee gronden van verschillende herkomst
Wijk, Kees van - \ 2016
Wageningen : Stichting Dienst Landbouwkundig Onderzoek (DLO) (Rapport / PPO/PRI 683) - 36 p.
akkerbouw - tuinbouw - veldgewassen - fosfaatuitspoeling - fosformeststoffen - fosfor - gewasopbrengst - arable farming - horticulture - field crops - phosphate leaching - phosphorus fertilizers - phosphorus - crop yield
Vanwege de eindigheid van de wereldvoorraad makkelijk winbaar fossiel fosfor en om fosforemissies uit (overbemeste) landbouwgronden naar grond- en oppervlaktewater te verminderen, is het Nederlandse landbouwbeleid gericht op het verlagen van fosforbemesting. Het doel van dit beleid is om de P-toestand in bodems met een hoge fosfortoestand te laten dalen en relatief lage toestanden in bodems niet meer dan landbouwkundig noodzakelijk te verhogen. Op termijn speelt de vraag hoe bij lage fosforbemesting toch nog goed gewassen te telen zijn. Het wordt steeds belangrijker om het fosfor dat in de bodem aanwezig is, te benutten. Binnen project Verbetering benutting bodemvoorraad fosfaat wordt onderzocht hoe dit kan en of dit gekwantificeerd kan worden. Het project wordt uitgevoerd door het Louis Bolk Instituut en PPOAGV.
Phosphorus recycling from the waste sector
Ruijter, F.J. de; Dijk, W. Van; Curth-van Middelkoop, J.C. ; Reuler, H. van - \ 2015
Plant Research International, Wageningen UR (Rapport / Plant Research International 641) - 29 p.
phosphorus - waste water - composts - recycling - sewage sludge - sludges - fosfor - afvalwater - compost - rioolslib - slib
An efficient use of phosphorus (P) is necessary as phosphate rock is a finite resource and P is essential for crop production. From the waste sector in the Netherlands, 23 Mkg P is sequestered in landfill, incineration ashes and cement. Flows containing P are discussed, together with options to recover P and reduce P losses, and the interactions between these options.
Kalibratie van het Landelijk KRW-Verkenner Model 2.0
Mulder, H.M. ; Cleij, P. - \ 2015
Deltares - 41 p.
kaderrichtlijn water - kalibratie - modelleren - stikstofretentie - voedingsstoffenretentie - fosfor - water framework directive - calibration - modeling - nitrogen retention - nutrient retention - phosphorus
Bij de laatste validatie van het Landelijk KRW-Verkenner Model (Cleij et al. 2014) is gebleken dat de concentraties voor N-totaal en P-totaal vaak matig tot slecht voorspeld worden. Eén van de manieren om de voorspellende waarde van een model te verhogen is kalibratie. Het LKM is echter modelparameter-arm, en de enige 'knoppen', waaraan wat betreft modelparameters gedraaid kan worden zijn de parameters van het eerste-orde afbraak proces voor -totaal en -totaal de a raakconstante ij en de temperatuurco ici nt De tot nu toe gebruikte retentieparameters zijn afkomstig van een vertaling van de retentieparameters van het KRW-ECHO systeem naar de retentieparameters voor de KRWVerkenner (Roovaart et al. 2012). Het in dit rapport beschreven onderzoek is via kalibratie gezocht naar een nieuwe set retentieparameters voor N-totaal en P-totaal, uitgaande van de tot nu toe gehanteerde parameterwaarden met als doel het voorspellend vermogen van het LKM op dit punt te verbeteren.
Phosphorus Response and Fertilizer Recommendations for Wheat Grown on Nitisols in the Central Ethiopian Highlands
Agegnehu, Getachew ; Nelson, Paul N. ; Bird, Michael I. ; Beek, Christy van - \ 2015
Communications in Soil Science and Plant Analysis 46 (2015)19. - ISSN 0010-3624 - p. 2411 - 2424.
Critical P concentration - Nitisol - phosphorus - relative yield - wheat

The provision of farmers with proper and balanced fertilizer recommendations is becoming increasingly important, for reasons of crop productivity, food security, and sustainability. Phosphorus (P) response trials with wheat were conducted on Nitisols at 14 sites in the central Ethiopian highlands during the 2010 and 2011 cropping seasons. The treatments, comprising six levels of P fertilizer (0, 10, 20, 30, 40, and 50 kg P ha−1), were arranged in a randomized complete block design with three replicates. Based on a yield difference between the control and the P treatments, 90% of sites responded to P fertilizer. Application of P fertilizer increased wheat grain yield, up to 30% more than the control. Extractable soil P concentrations (Bray 2, 0–15 cm deep) 3 weeks after planting significantly responded to P fertilizer rate. The critical P concentration (for 90% relative yield) was 13.5 mg kg−1. Most sites tested had Bray 2 P values −1. In the absence of a soil test, a recommendation of 40 kg P ha−1, resulting in the best response overall, could be made for the first year of application. We also recommend that to prevent a potential loss of wheat yield, a maintenance application of at least 5–12 kg P ha−1 be applied every year, irrespective of the calculated recommended rate, in order to replace P exported from the field in produce. Further field trials are required to determine interactions between P response and the effects of climate, soil properties, and other management practices.

Dutch research on animal manure to ensure authenticity and quality
Pustjens, A.M. ; Derikx, P.J.L. - \ 2015
manures - fertilizers - agriculture and environment - phosphorus - nitrogen - environmental legislation - netherlands - mest - kunstmeststoffen - landbouw en milieu - fosfor - stikstof - milieuwetgeving - nederland
The Netherlands is known for its high livestock density. As a result there is a (local) surplus of animal manure. Legislation on the use of animal manure and other organic and inorganic fertilizers, is put into force to ensure environmental sound use of phosphorus and nitrogen.
Phosphorus metabolism in dairy cattle : literature study on recent developments and gaps in knowledge
Goselink, R.M.A. ; Klop, G. ; Dijkstra, J. ; Bannink, A. - \ 2015
Wageningen : Wageningen UR Livestock Research (Livestock Research rapport 910) - 36
dairy cattle - phosphorus - nutrient requirements - animal nutrition - metabolism - melkvee - fosfor - voedingsstoffenbehoeften - diervoeding - metabolisme
Goal of this literature study is to define the uncertainties related to P requirement models and ways to make them more precise and more reliable than current systems and to find biomarkers to monitor P balance in living animals. Milk P is an important factor in P balance, and concentration may vary between individual cows. Bone represents a large P reserve and can have a profound impact on cow P balance and plasma P regulation. Plasma P concentration is still the most commonly used diagnostic measurement available to judge the P status of an animal, with all restrictions for good interpretation; new biomarkers defining P status are needed. Further research into mechanisms and quantification of the is needed to improve our understanding of P metabolism.
Closing Domestic Nutrient Cycles Using Microalgae
Vasconcelos Fernandes, T. ; Shresthat, R. ; Suit, Y. ; Papini, G. ; Zeeman, G. ; Vet, L.E.M. ; Wijffels, R.H. ; Lamers, P.P. - \ 2015
Environmental Science and Technology 49 (2015)20. - ISSN 0013-936X - p. 12450 - 12456.
algen - afvalwater - afvalwaterbehandeling - stikstof - fosfor - biomassa productie - proefopzet - nieuwe sanitatie - algae - waste water - waste water treatment - nitrogen - phosphorus - biomass production - experimental design - new sanitation
This study demonstrates that microalgae can effectively recover all P and N from anaerobically treated black water (toilet wastewater). Thus, enabling the removal of nutrients from the black water and the generation of a valuable algae product in one step. Screening experiments with green microalgae and cyanobacteria showed that all tested green microalgae species successfully grew on anaerobically treated black water. In a subsequent controlled experiment in flat-panel photobioreactors, Chlorella sorokiniana was able to remove 100% of the phosphorus and nitrogen from the medium. Phosphorus was depleted within 4 days while nitrogen took 12 days to reach depletion. The phosphorus and nitrogen removal rates during the initial linear growth phase were 17 and 122 mg·L–1·d–1, respectively. After this initial phase, the phosphorus was depleted. The nitrogen removal rate continued to decrease in the second phase, resulting in an overall removal rate of 80 mg·L–1·d–1. The biomass concentration at the end of the experiment was 11.5 g·L–1, with a P content of approximately 1% and a N content of 7.6%. This high algal biomass concentration, together with a relatively short P recovery time, is a promising finding for future post-treatment of black water while gaining valuable algal biomass for further application.
Phosphorus mobilization and biocontrol of plant pathogens combined in one strain – results of a fungus and a bacterial inoculant
Postma, J. ; Nijhuis, E.H. - \ 2015
aardbeien - tomaten - potproeven - gewasbescherming - grondverbeteraars - compost - biochar - schimmelbestrijding - biologische bestrijding - glastuinbouw - mycorrhizae - fosfor - strawberries - tomatoes - pot experimentation - plant protection - soil amendments - composts - fungus control - biological control - greenhouse horticulture - mycorrhizas - phosphorus
How two important crops, strawberry and tomato grown in potting soil, benefit from microbial inoculants.
Achtergrondconcentraties in het oppervlaktewater van HHNK : Hoofdrapport: Analyse achtergrondconcentraties voor stikstof en fosfor op basis van water- en nutriëntenbalansen voor het beheergebied van HHNK
Boekel, E.M.P.M. van; Roelsma, J. ; Massop, H.T.L. ; Mulder, H.M. ; Jansen, P.C. ; Renaud, L.V. ; Hendriks, R.F.A. ; Schipper, P.N.M. - \ 2015
Wageningen : Alterra, Wageningen-UR (Alterra-rapport 2475) - 129
grondwater - grondwaterkwaliteit - stikstof - fosfor - waterbalans - kaderrichtlijn water - modellen - nederland - groundwater - groundwater quality - nitrogen - phosphorus - water balance - water framework directive - models - netherlands
In opdracht van Hoogheemraadschap Hollands Noorderkwartier zijn voor 42 deelgebieden theoretische achtergrondconcentraties afgeleid van stikstof en fosfor in het oppervlaktewater. De resultaten zijn per deelgebied in 42 achtergrondrapporten vastgelegd. In dit hoofdrapport wordt een overzicht gegeven van de toegepaste methodiek, wordt een samenvatting gegeven van de resultaten en wordt aandacht besteed aan de plausibiliteit van de nutriëntenbalansen. De theoretische achtergrondconcentraties zijn afgeleid op basis van water- en stofbalansen. De waterbalans is opgesteld op dagbasis met meetgegevens (neerslag, verdamping en lozingen) en modelresultaten (kwel en afvoer naar de RWZI) als balansposten. Het inlaatvolume is als ontbrekende balanspost ingeschat door de gemeten en berekende gebiedsafvoer te vergelijken. De nutriëntenbalans is opgesteld met behulp van het modelinstrumentarium ECHO, waarin beschikbare metingen, data en kennis zijn gecombineerd met regionale informatie (landgebruik, bodemtype, Gt-klasse). De herkomst van de nutriënten in het oppervlaktewater is in beeld gebracht en opgesplitst naar antropogeen (rioolwaterzuiveringsinrichtingen of RWZI’s, bemesting, etc.) of natuurlijk (kwel, veenoxidatie, etc.).
Soil carbon storage and stratification under different tillage/residue-management practices in double rice cropping system
Chen, Z. ; Zhang, H. ; dikgwatlhe, S.B. ; Xue, J. ; Qiu, K. ; Tang, H. ; Chen, F. - \ 2015
Journal of Integrative Agriculture 14 (2015)8. - ISSN 2095-3119 - p. 1551 - 1560.
no-tillage - organic-matter - conservation tillage - climate-change - sequestration - impacts - agriculture - phosphorus - nitrogen
The importance of soil organic carbon (SOC) sequestration in agricultural soils as climate-change-mitigating strategy has become an area of focus by the scientific community in relation to soil management. This study was conducted to determine the temporal effect of different tillage systems and residue management on distribution, storage and stratification of SOC, and the yield of rice under double rice (Oryza sativa L.) cropping system in the southern China. A tillage experiment was conducted in the southern China during 2005-2011, including plow tillage with residue removed (PT0), plow tillage with residue retention (PT), rotary tillage with residue retention (RT), and no-till with residue retention on the surface (NT). The soil samples were obtained at the harvesting of late rice in October of 2005, 2007 and 2011. Multiple-year residue return application significantly increased rice yields for the two rice-cropping systems; yields of early and late rice were higher under RT than those under other tillage systems in both years in 2011. Compared with PT0, SOC stocks were increased in soil under NT at 0-5, 5-10, 10-20, and 20-30 cm depths by 33.8, 4.1, 6.6, and 53.3%, respectively, in 2011. SOC stocks under RT were higher than these under other tillage treatments at 0-30 cm depth. SOC stocks in soil under PT were higher than those under PT0 in the 0-5 and 20-30 cm soil layers. Therefore, crop residues played an important role in SOC management, and improvement of soil quality. In the 0-20 cm layer, the stratification ratio (SR) of SOC followed the order NT>RT>PT>PT0; when the 0-30 cm layer was considered, NT also had the highest SR of SOC, but the SR of SOC under PT was higher than that under RT with a multiple-year tillage practice. Therefore, the notion that conservation tillage lead to higher SOC stocks and soil quality than plowed systems requires cautious scrutiny. Nevertheless, some benefits associated with RT system present a greater potential for its adoption in view of the multiple-year environmental sustainability under double rice cropping system in the southern China.
Impact of nitrogen deposition on larval habitats: the case of the Wall Brown butterfly Lasiommata megera
Klop, E. ; Omon, B. ; Wallis de Vries, M.F. - \ 2015
Journal of Insect Conservation 19 (2015)2. - ISSN 1366-638X - p. 393 - 402.
british butterflies - herbivorous insects - pararge-aegeria - limitation - climate - biodiversity - adaptation - phosphorus - landscape - trends
Nitrogen deposition is considered as one of the main threats to biodiversity and ecosystem functioning. Three mechanisms have been proposed to explain the detrimental effect of excess nitrogen on butterflies: loss of host plants, deterioration of food plant quality and microclimatic cooling in spring. Here, we investigated whether these mechanisms might explain the dramatic recent decline of the Wall Brown butterfly Lasiommata megera. Monitoring data from the Netherlands indeed show a greater decline at higher critical load exceedance of nitrogen deposition. Loss of host plants is not a likely explanation of the decline for this grass-feeding species. In a greenhouse experiment, we only found beneficial effects of nitrogen fertilization on larval performance, which seems to rule out a nutritional cause; application of a drought treatment did not result in significant effects. Microclimatic conditions at overwintering larval sites of L. megera and the related but increasing Pararge aegeria provided a possible clue. In comparison with larval sites of P. aegeria, those of L. megera showed higher temperatures at the mesoscale and less plant cover and more dead plant material at the microscale. L. megera caterpillars were also found closer to the shelter of vertical structures. The greater dependence on warm microclimates suggests that microclimatic cooling through excess nitrogen contributes to the recent decline of L. megera.
Nutriënten: bronnenanalyse en afleiding van achtergrondconcentraties als basis voor het bijstellen van KRW-doelen
Schipper, P.N.M. ; Boekel, E.M.P.M. van; Ee, G. ; Hermans, J. - \ 2015
H2O online (2015)10 aug..
oppervlaktewater - nutriëntenstromen - fosfor - stikstof - waterbalans - modellen - noord-holland - surface water - nutrient flows - phosphorus - nitrogen - water balance - models
In de helft van de regionale wateren blijven nutriënten een beperkende factor om KRW-doelen te bereiken. Is een groot deel daarvan misschien natuurlijk? Een belangrijke vraag, omdat de KRW de mogelijkheid geeft om achtergrondbelasting van nutriënten in de doelen te verrekenen. Uit het hieronder beschreven onderzoek weet HHNK nu per waterlichaam in zijn gebied waar de nutriënten vandaan komen en wat daarin het aandeel natuurlijke achtergrond is. Deze kennis is essentieel om KRW-doelen onderbouwd te kunnen bijstellen en om te kunnen bepalen waar welke maatregelen efficiënt zijn.
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