1. N and P balances in Denmark 1985-2005 on national and regional scale
Finn P. Vinther and Arne Kyllingsbæk
UNIVERSITY OF AARHUS
Faculty of Agricultural Sciences
Dept. of Agroecology and Environment
Blichers Allé 20, P.O. BOX 50
DK-8830 Tjele
Former; Danish Institute of Agricultural Sciences (DIAS)

2. Danish Institute of Agricultural Sciences
Foulum
Faculty of Agricultural Sciences
Flakkebjerg
Årslev

3. Inst. of Agroecology
and Environment

4. Methodology
The balances have been calculated according to methodologies described in the OECD/EUROSTAT handbooks on Gross Nitrogen Balances (Dec. 2003) and Phosphorus Balances (March 2004), respectively.

5. Input: Inorganic fertilisers: Directly from Statistics Denmark.
Organic fertilisers (excl. livestock manure): The amount of sewage sludge and industrial waste products is estimated based on data from Danish Environmental Protection Agency along with information on content of N and P.
Livestock manure: Number of animals in the OECD categories is provided by Statistics Denmark. Manure coefficients (ex animal) for each animal category [kg N and P/head/year] are each year updated by Inst. of Animal Health, Welfare and Nutrition, University of Aarhus.
N2 fixation by grass-clover and legumes: Area with leguminous crops is provided by Statistics Denmark and N2 fixation coefficients for a given crop [kg N/ha] are estimated using an empirical model Høgh-Jensen et al. (2003, 2004).
Atmospheric deposition: Based on annual estimates from NERI
Seeds: Amount from Statistics Denmark and concentrations of N and P are obtained from a ‘Feed stuff’ database providing this information for a large number of feed stuff and crops. The database is updated at regular intervals (latest 2005). Cereals are analysed for N and P content annually.

6. Output:
Harvested and fodder crops: Area and yield of various crops, such as cereals, oil seed crops and fodder crops are obtained from Statistics Denmark and concentrations of N and P are obtained from the ‘Feed stuff’ database; see above.

7. Balance: Field balance (National level) Field N surplus:
Volatilisation
Field balance
(National level)
Field N surplus:
- NH3 volatilisation
Standard coefficients
- Denitrification
An empirical model SIMDEN
= N leaching

8. Results

9. Results
Total
Dairy cows
Cattle
Pigs
Total
Fattening pigs

10. Nitrogen input Total Fertilisers Animal manure
N2 fixation, deposition and seed

11. Crop yields

12. Crop yields
- 0.8 kg N/ha/year

13. Nitrogen Use Efficiency
0.6 % per year

14. N surplus
- 4 kg N/ha/year

15. Improvements in NUE resulting in reduced
N surplus are primarily the result of legislations
concerning:
Maximum limits on application of fertilisers for individual crops
Statutory norms for the proportion of manure N assumed to be plant available, e.g. pig slurry 70%
Obligatory fertiliser plans

16. Phosphorus
Total
Animal manure
Fertilisers
Deposition and seed

17. Regional balances ?

20. Administrative units
Communes

21. Administrative units
Counties
Units at Statistics Denmark until 2007

22. Administrative units
Regions

23. Units at Statistics Denmark from 2007

24. Thank you for
your attention !!!

26. N2 fixation: N2 fixation (kg N/ha) =
Høgh-Jensen, H., Loges, R., Jensen, E.S., Jørgensen, F.V. & Vinther, F.P. (1998) Empirisk model til kvantificering af symbiotisk kvælstoffiksering i bælgplanter. I Kristensen, E.S. & Olesen, J.E. (eds.) Kvælstofudvaskning og -balancer i konventionelle og økologiske produktionssystemer. FØJO-rapport nr. 2,
Høgh-Jensen, H., Loges, R., Jørgensen, F.V., Jensen, E.S. and Vinther, F. P. (2004) An empirical model for quantification of symbiotic nitrogen fixation in grass-clover mixtures. Agricultural Systems 82,
N2 fixation (kg N/ha) =
Harvested legume DM (kg/ha) * N% * Pfix *
(1 + Proot+stuble + Ptrans-soil + Ptrans-animal + Pimmobil)

27. Denitrification & N2O emission:
Vinther, F. P. and Hansen, S. (2004) SIMDEN – a simple model for quantification of N2O emission and denitrification. DJF report 104, 1-47 (In Danish)
Input variables:
Amount of N applied
Clay content of the soil
SIMDEN

28. SimDen compared to measured values:
Danish measurements

29. Spain (Vallejo et al., 2004)

30. The Netherlands (Zwart et al., 2004)