4th International Phosphorus Workshop


Critical evaluation of options for
reducing phosphorus loss from agriculture


August 16th - 19th, 2004


Wageningen International Conference Centre (WICC)
Lawickse Allee 9, 6701 AN Wageningen, The Netherlands

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Click here for information on the next International P Workshop: Denmark 2007

The workshop was sponsored by the Dutch Ministries of :
- Agriculture, Nature and Food Quality
- Spatial Planning, Housing and the Environment
- Transport, Public Works and Watermanagement

Last update (dd-mm-yr): 30-9-04. See "Updates web site" in left column.


Background and goals

The role of phosphorus in eutrophication of surface water has long been recognized. Negative effects of eutrophication include: reduced biodiversity of aquatic ecosystems and surface water quality, and algal blooms that restrict the use of surface waters for recreation and drinking water production. Algal toxic substances have caused fish kills and animal and human diseases in the past. Reduction of phosphorus input to surface waters is thus necessary, mostly starting with diminishing industrial losses, precipitating P in sewage water treatment plants and increasing the number of households that are connected with sewerage systems. Due to these reductions the relative contribution of agriculture to total P input to aquatic systems increases to 50 or even 90 % in many watersheds.

In Europe, the Water Framework Directive will force authorities of watersheds to improve the ecological status of the water. For many waterways this implicates a reduction of nutrient inputs. It is foreseen that this has especially a large impact for phosphorus.

The need for reducing P loss from agriculture is thus clear, and studies to find the main locations where P loss starts and on transfer routes to rivers and lakes have received much attention recently. Research on reducing P loss is also expanding, and many different options are proposed and tested (and sometimes rejected) under different soil, crop and environmental conditions. Thus, there is a strong need for a critical evaluation of these options, in order to reduce further research where little benefit is likely and to expand research on options that have proven to be successful.

In the past, International Phosphorus Workshops (1995 Wexford, 1998 Antrim, 2001 Plymouth) have greatly contributed to increase our knowledge about the relation between agriculture and P losses, and about transfer of P from soil to water. The 4th International Phosphorus Workshop was a platform for evaluating the effectiveness, under varying conditions, of different types of options for reducing P losses from fields, and the transport of P in, or effects of P on surface waters. Discussions included aspects like the effectiveness of options for different forms of P (inorganic, organic, and particulate), economic aspects, and interaction with the nitrogen cycle.

Source orientated options, like a (drastic) reduction of P input to agriculture, or prevention of P transport from agricultural fields, may be considered to be most effective for avoiding unwanted effects. However, when considerable amounts of P have accumulated in the soil in the past, a reduction in P loss may take (much) time. Therefore, also ("end-of-pipe") options for reducing P transport in surface water and for abating consequences of eutrophication in surface water were discussed.

Wim Chardon, workshop organiser

Tel +31 (0)317 47 46 02, Fax +31 (0)317 41 90 00


Post workshop information

The program started on Sunday evening (August 15th) with a welcome drink in the WICC building.

For the full program click
For the list of delegates click on list.
For the workshop proceedings click on pdf (840 K).
Note: some minor changes have taken place in both the program and the delegates list that are part of the proceedings; see update or the final versions mentioned above.
Click here for a report of the workshop. The final version of the report deviates only slightly from the draft version: the paragraphs on constructed wetlands and on human nutrition have changed, and evaluation of cost effectiveness was added as a specific research need.

Click on JEQ for a list of publications from the workshop.

Click on photo (zip-file of 18 MB!) for a photographic impression of the workshop. The photos were made by Lowie van Liere from the Netherlands.

In brief, the program was as follows:

Sunday evening

Registration, welcome drink (19.30-21.30)

Monday morning

Registration, plenary lectures

Monday afternoon

Plenary lectures; poster session

Tuesday morning

Plenary lectures

Tuesday afternoon

Excursion, conference dinner

Wednesday morning

Plenary lectures

Wednesday afternoon

Plenary lectures

Thursday morning

Plenary lectures, discussion, conclusions

Posters were presented during the workshop on Monday, Tuesday and Wednesday; a poster session was part of the program. There was no limitation on the total number of posters that could be presented; the deadline for submission of abstracts was 1 June 2004. The usable size of the poster boards is 115x115 cm.
A limited number of offered presentations can be selected for oral presentations, based on extended abstracts received before 24 April 2004. Click on template for the format to be used for the extended abstract. Upon submitting the abstract by email please indicate whether you wish to give an oral presentation or want to present a poster.
The length of oral presentations is 20 min. for offered contributions, including a few min. for technical questions. The length of invited papers is 30 min., including a few min. for technical questions.
Equipment for Power Point presentations, a slide projector and a overhead projector will be available.

Topics and speakers of invited presentations are summarized below:


Invited speaker
Alteration of phosphorus content in diets for livestock: Impact on animal performance and health, and the environment A. Jongbloed - H. Valk, The Netherlands
Phosphorus forms and mobility due to manipulating phosphorus in animal feed R. Maguire, North Carol. State Univ. USA
Immobilization of phosphorus in soil and manure using Al-based treatments and byproducts N. Basta / L. Dayton, Ohio State Univ. USA
Erosion and phosphorus mobility from agricultural catchments J. Cox, CSIRO Australia
A role for sedimentation ponds and constructed wetlands? B. Braskerud, Jordforsk Norway
Methods to abate eutrophication symptoms in lakes P. Boers - L. van Liere, The Netherlands
Importance of ‘incidental’ P losses on different scales P. Haygarth, North Wyke, UK
Interaction between nitrogen and phosphorus losses at watershed scales: Compromise or conflict? B. Foy, Dept Agric. N.Ireland
River basin management plans for the European Water Framework Directive B. Kronvang, Denmark
Risk assessment methodologies L. Heathwaite, Sheffield, UK
Cost effectiveness of options: withdrawn; a poster on this topic will be presented by Haygarth et al.

Organisation of the workshop



For a (provisional) list of options for reducing P loss from agriculture click on
options. The list will continuously be updated in an interactive process with persons interested in the subject and/or the workshop. Any contributions are thus highly appreciated. The list will also be used for discussing known experience (either positive or negative) with these options. References of publications in which this experiences are discribed will be collected (if provided by authors) under "References".



References of publications in which experiences with options is described, will be collected: click on
references for an overview. Contributions for extending this list are highly appreciated since this will be helpful for preparing the workshop.



Extended abstracts are published on the web site as soon as possible after receipt, and will be collected in a report that will be distributed at the beginnning of the workshop. A selection of the invited and voluntary papers will be offered for publication to the J. of Environmental Quality.


Time schedule of preparation of the workshop:

October 2003

circulation of first announcement

December 2003

second announcement

end of February 2004

third announcement with program details

23 April 2004

deadline for submitting extended abstracts for oral contributions

15 May 2004

registration costs increase from 175 to 225 Euro

1 June 2004

deadline for submitting extended abstracts for posters


Workshop Organising Team

Workshop Organiser:
Wim J. Chardon (Alterra, Wageningen UR, Soil Science Centre, Wageningen, Nl)

Workshop Secretary:
All correspondence relating to the workshop (extended abstracts, registration, enquiries) should be addressed to the workshop secretary:
Mrs. Linda van Kleef, (Alterra, Wageningen UR, Soil Science Centre, PO Box 47, 6700 AA Wageningen, Nl)
Tel + 31 317 474 481, Fax +31 317 419 000, email:

Web page: http://www.ipw4.alterra.nl/

Local Organising Committee:
G.F. Koopmans, O. Oenema, O.F. Schoumans (Alterra, Wageningen UR, Wageningen, Nl)

Scientific advisors:

P.C.M. Boers

Inst. for Inland Water Management and Waste Water Treatment (RIZA), Lelystad, Nl

P.M. Haygarth

Inst. of Grassland and Environmental Research, North Wyke Research Station, UK

L. van Liere

National Inst. for Public Health and the Environment, Bilthoven, Nl

A.N. Sharpley

United States Department of Agriculture, Pennsylvania, USA

J.T. Sims

Univ. of Delaware, Newark, USA

B. Ulén

Swedish Univ. Agric. Sciences, Uppsala, Sweden



The fee for the workshop amounts 175 Euro (incl. VAT) until May 15th, after this date the fee will be 225 Euro.
This includes access to the workshop, welcome drink, book with abstracts, coffee/tea, lunches, excursion, and workshop dinner. The fee must be paid upon registration.
Costs for the hotel accommodation have to be paid directly to the hotel upon leaving.



Hotel rooms are available on 3 locations; WICC is the conference building (rooms in WIR are larger than in WICC). In the 3 hotels a number of rooms are reserved for the workshop from August 14th or 15th until ultimately August 19th (leave). For these rooms and dates arrangements can be made via the registration form, other room types or dates outside this period must be arranged directly via the hotel (see websites below).
Click on
bookings for a list of rooms booked + arrival dates.

WICC (web)
* single room
* double room (2 separate beds)
WIR (5 min. walking from WICC) (web)
* single room
* double room (2 separate beds)
Hotel De Wageningse Berg (uphill,
2.5 km from WICC)
* double room (1 large bed, single use)
* twin room (2 beds, double use)

€ 66.50
€ 91.50

€ ..78.50
€ 108.00

€ 62.50
€ 97.50



* Prices include breakfast and VAT, but not local tax (€ 0.35 per person per night). In hotels, payment with major credit cards is possible (WICC and WIR do not accept Diners). All rooms have shower, toilet, tv, and telephone.


For registration click on


* payment with a credit card is possible, fill in a form and send it to the bureau, see registration page.

* those who pay by cheque or bankers draft: calculate fee in your currency using actual exchange rate.

* invited speakers: please fill in that you want to pay by cheque; this will, of course, be corrected.

* those who want to share a room: do not reserve both, only once per combination!



Wageningen International Conference Centre (WICC)
Lawickse Allee 9
6701 AN Wageningen
the Netherlands
T +31 (0)317 49 01 33
F +31 (0)317 42 62 43
E reception@wicc-wir.nl

click here for a map of the centre of Wageningen.



Airplane + train
From the main airport Schiphol near Amsterdam you travel by train to the railway station called Ede-Wageningen, which is about 7 km north of Wageningen. At Schiphol you buy a ticket on the ground floor, the train leaves one floor below from track 2 or 3. After 13 min from Schiphol you have to change trains at a station called Duivendrecht, and then you can either have a direct train to Ede-Wageningen (45 min.) or you have to change trains again in Utrecht, after about 20 min. You can plan your travel from Schiphol to Ede-Wageningen on:
http://www.ns.nl/domestic. Take a bus or taxi to Wageningen (see below).

From the east or north: travel to station Arnhem. Take a bus to Wageningen, bus lines 50, 86 or 251, stop 'Stadsbrink'. Walk to WICC (5 min.) or WIR (1 min.). For hotel "De Wageningse Berg" take line 86 that brings you close to the hotel (5 min. walk).
From the west or south: travel to station Ede-Wageningen via Utrecht.

Bus / taxi from railway station Ede-Wageningen to Wageningen
Take a bus to Wageningen, bus lines 83, 84 or 86, stop 'Stadsbrink'. Walk to WICC (5 min.) or WIR (1 min.); costs are ca. 2.50 Euro. For hotel "De Wageningse Berg" take line 86 that brings you close to the hotel (5 min. walk). Alternative: take a taxi, costs are 20-25 Euro. Unfortunately, a shared taxi ("treintaxi") is not available anymore.

By car
Visit the web site of the WICC, www.wicc-wir.nl, choose 'route', and you can prepare a route discription from the place where you depart.


List of updates of web site (dd-mm-yr).

10-11-05: list of publications in J. Environ. Qual. added (see post workshop info)
30-09-04: final version of workshop report added (see program)
13-09-04: draft version of workshop report added (see program)
13-09-04: photos added
09-08-04: updated list of delegates added
03-08-04: pdf-version of proceedings added
30-07-04: final program added (see program)
26-07-04: list of rooms booked + arrival dates added (see accommodation)
22-07-04: length of oral presentations added (see program)
22-07-04: program changed (discussions skipped, see program)
27-05-04: invited paper on Cost effectiveness of options withdrawn
13-05-04: number bank account corrected on registration form
19-04-04: effective size of posters boards added (115x115 cm)
19-04-04: deadline added for submitting abstracts for poster presentations
13-04-04: deadline changed for submitting abstracts for oral presentations
09-04-04: name of Journal added for publication of a selection of papers
09-04-04: invited speakers added for Manipulating phosphorus in animal feed
18-03-04: list of received abstracts added (see menu on left)
08-03-04: reformulation of Program section: no limits to number of posters
03-03-04: payment by credit card is now possible
26-02-04: list of updates added
26-02-04: list of invited speakers added (see Program)
26-02-04: registration form added (see Registration)
09-02-04: map of Wageningen added (see Location)