1. Nutrient balances
Anne Miek Kremer
07/

2. Content Response overview Planning Notes Format Coefficient revisions
Missing data
Dissemination
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3. Response overview: Data received: P national: CH, ES, HU, EE, UK, DE
N national: CH, ES, HU, PL, SI, EE, UK, DE
N regional: PL
Response to enquiry:
AT, NO, EL, IE
Deadline:
End of October
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4. Planning Evaluation of balances: Diredate recommendations
Define scope
Harmonisation of coefficients and data sources
Metadata
Methodological improvements
Diredate recommendations
Working Group March 2011
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5. Please note: P balance; unit = P (not P2O5).
Excretion coefficients should not exclude volatilisation of N.
Metadata (data source, type of data source, coefficients, coefficient revisions, notable trend breaks) .
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6. Please note:
MS are kindly asked to send updated data on crop statistics to Eurostat. (apro_cpp).
In future we will pre-fill balances: crop statistics, livestock statistics, land-use, fertiliser consumption.
MS would only need to send: fertilisers consumption (excl manure, mineral fertilisers), coefficient revisions, grassland production, crop residues, seeds an planting material, manure withdrawals.
Format.
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7. Example format
format industrial crops
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8. Coefficient revisions
They can reflect:
Real change
Change in methodology/data source etc
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9. Coefficient revisions – Real change
Example: N-coefficient fattening pigs 2000 is 15 kg N/tonne and in kg N per tonne.
Lineair regression: 2001 (14.8), 2002 (14.6), 2003 (14,4)….2009 (13.2).
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10. Coefficient revisions
Revision does not reflect real change
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11. Coefficient revisions
Revision does not reflect real change:
Recalculate previous years with new coefficients.
Detailed coefficients, detailed data on livestock/ crops previous years not available; assume constant distribution.
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12. Example
New coefficients available from 2000 on bovine animals <1 year (30 kg N/head), bovine animals 1-2 years (50 kg N per head), bovine animals >2 years (70 kg N/head).
Before 2000 data on animal numbers only available for the aggregate cattle.
Recalculate 1999:
-Cattle in 1999 = 1000 heads.
-Average % of bovine <1 year ( )=30%
Manure excretion bovine < 1 year in 1999 = 0.3*1000*30 = 9000 kg.
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13. Missing data
Imputation: for instance linear regression or using data of previous year, or three year average.
Please mark imputed data in blue.
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14. Dissemination
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15. Questions to MS Do members of the WG agree with:
a) Coefficient revisions:
In the case of a real change:
- to recalculate years between old an new coefficient with coefficients corrected by linear regression?
In case revision does not reflect real change:
to recalculate all previous years using the new coefficients?
If coefficients become available on a more detailed level, but data on livestock numbers/crop areas are not available in the same detail for previous years, to disaggregate the animal numbers using an estimate of the average distribution of animals within a group over time?
b) Imputing missing data?
c) Data to be disseminated in absolute quantities as shown in previous slide?
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