1. Regional representativeness of nitrogen and phosphorus excretion factors
Task 4
Hans Kros
Alterra
Workshop ‘Excretion factors’
Eurostat, Luxemburg, 28 March 2014

2. Objective Task 4
Objective Task 4: To analyse the appropriateness of estimating regional excretion factors for animal categories

3. Outline
Need for regional differentiation of N and P excretion coefficients
Analysis of the practical feasibility of a regional differentiation of N and P excretion coefficients
An overall assessment of the feasibility of a regional differentiation of N and P excretion coefficients

4. Need for regional excretion coefficients
Regional differentiation of N and P balances and losses:
Relevant for NH3 emissions and NO3 and P leaching
Regional differentiation of policy measures:
Nitrate Vulnerable Zones (NO3)
Natura 2000 sites (NH3)

5. Regional differences in N losses in EU
De Vries et al., in: The European Nitrogen Assessment. Chapter 15, 2011.

6. Regional differences N excretion coefficients
=> a variation of ± 20%

7. Causes of regional differences
Excretion coefficients may differ regionally because of:
Animal breeds (e.g., large vs small; fast vs slow)
Production systems (e.g., organic vs common)
Production levels (e.g., high vs low)
Feed composition (e.g. differences in N and P contents)
Housing systems (free-range vs housed)

8. Assessment of regional differences
For pigs and poultry the feeding regimes show a relatively low variability within the EU
For cattle, differences in milk production, breeds and animal feed cause regional differences in excretion coefficients
In Flanders, N excretion by dairy cows (kg N per head) is function of the areas (ha) of grassland and maize land per LU:
Nexcretion = × Grass × Maize
R2 = 0.71  Wustenberghs et al. (2007)

9. Inventory of regional excretion coefficients
Countries
N excretion coefficients
P excretion coefficients
Belgium
Yes: Flanders, Walloon and Brussels
Denmark
No, but feasible through available farm statistics
Germany
Yes: per bündesland (NEC) -
Italy
Yes, some regions do have region-specific rates
Netherlands
Yes, feasible through available farm statistics
United Kingdom
Yes, separate values for N. Ireland and Scotland
Not available
See task 1, country report

10. Downscaling national data to regions
Needed information per region:
Animal number per animal category
Animal production per animal category
Intake and composition of the animal feed
Production levels and systems
Generally available at regional level:
Livestock numbers (at NUTS2)
Estimations of N balances in Nitrate Vulnerable Zones

11. Downscaling livestock numbers
For
Reasonable for grazing animals
Less good for pigs and poultry
Neumann et al., 2009, Landscape Ecol., 2009

12. Downscaling grassland production
Smit et al. Agricult. Sys., (2008)

13. Influencing factors: availability and uncertainty
Livestock category
Factor
Effect on excretion 1)
Data availability at regional scale 2)
Uncertainty 3)
Acquiring possibility 4) P N
Dairy cattle
Feed intake ++ +
Diet composition -
Grazing time
Milk production level
Live weight gain
N and P contents
Other cattle ?
Pigs
Feed composition
Phytase addition
Fattening period
Poultry
Amino acid addition
Egg yield
1) ++: Factor causing a large change; +: moderate change; 0: no or small effect; ? unknown
2) +: Available at regional scale; ±: only for some MS available at regional scale; 0: not available at regional scale; ? unknown
3) ++: Large uncertainty; +: moderately large uncertainty; 0: small uncertainty; ? unknown
4) Refers to whether available data can be used by third parties or that the use is restricted, e.g. due to privacy protection: +: Disclosable for regional applicability; -: undisclosable for regional applicability; ? unknown

14. Estimated costs of regional differentiation
One-off costs
Infrastructure: 2 fte, (coordination: 0.5 fte, protocol development: 0.5 fte, liaison and dbms: 1 fte)
Collection of regional data per MS: 0.5 fte per MS
16 fte => ~ 650 k€
Yearly costs
0.08 fte (2 wk) fte (1 wk)× 28 = 1.2 fte
=> ~ 50 k€ per year
1) based on mean loan EU of 40 k€ per year

15. Conclusions Regional excretion factors are needed for:
Regional GNB and GPB
Regional N and P losses
Some countries already use regional specific excretion coefficients (variation ± 20%)
Downscaling of excretion coefficients based on auxiliary data is promising for grazing animals, but less appropriate for pigs and poultry
Estimated costs needed for regional data collection:
650 k€ of one-off costs
50 k€ of yearly costs

16. Recommendations
To consider regional excretion coefficients especially for dairy and beef cattle
To use regional excretion coefficients if differences between regional means are:
>20%

17. Thank you

18. Downscaling Management data
SEAMLESS: Agri-environmental Zones (AEnZ): subdivision of the European landscape into 238 relatively homogeneous units in view of agronomy (Elbersen et al., 2006; Kempen et al., 2007)
Capri: down scaled farm management information for use at smaller spatial units. (Leip et al. Biogeosciences, 2008; Curr. Opin. Environ, 2011)