EUROSTAT
Directorate E: Agriculture and environment statistics; Statistical Cooperation
Unit E1: Agriculture statistics - methodology /
Luxembourg, 10-11 September 2007
Joint Eurostat, OECD, EEA and JRC
Workshop on methodological issues and Coordination meeting for TAPAS actions "CALCULATING REGIONAL GROSS NUTRIENT BALANCES”
Meeting of 10 and 11 September 2007 in Luxembourg
BECH Building, Room: Quetelet - Beginning 09:30 a.m.
Minutes of the meeting held on
1011 September 2007
Chairman: J. Selenius
Agenda: see annex I
Participants: see annex II
All meeting documents and presentations are available on the Circa-site: http://circa.europa.eu/Members/irc/dsis/agrienv/home
1. Adoption of the agenda and presentation of the objectives of the meeting
The agenda was adopted without changes (annex 1).
Nutrient balances are a key agri-environmental indicator. High surpluses highlight potentially excessive agricultural nutrient use and the potential for adverse effects upon water and air quality. Monitoring of a surplus over a period of years helps also in assessing the effectiveness of agri-environment policy measures. Because of these factors nutrient balances are included in many indicator lists in Eurostat, EEA and OECD.
Current nutrient balance methods are, however, subject to significant uncertainty. This uncertainty reduces the value of balances in highlighting nutrient surplus hotspots and clouds assessment of the impact of agri-environmental policies.
The key objectives of the meeting were:
· to identify the areas of weaknesses and uncertainty
· to identify ways in which to improve methodologies and data
· to find harmonised or consistent approaches so that estimates between countries and regions are comparable
· to evaluate different approaches
2. Latest developments on agri-environmental indicators and other indicator systems where nutrient balances are included
The Commission Communication (COM(2006)508)[1] was published in September 2006. Three key challenges for future work on EU agri-environmental indicators were identified:
· streamlining the IRENA indicator set, while strengthening its relevance for policy purposes;
· consolidating the selected set of indicators, extending the coverage to the new Member States and correcting existing weaknesses;
· setting up a permanent and stable arrangement needed for the long-term functioning of the indicator system.
The Council of Agriculture and Fisheries (19-21.12. 2006) stated that a coherent set of agri-environmental indicators is required in order to capture the regional diversity of agriculture and environmental conditions as well as their positive and negative influences. It also acknowledged the need of comparable data at appropriate geographical level. It decided that a long-term information system for monitoring environmental integration is to be set up, with the help of the Permanent Committee on Agricultural Statistics (CPSA).
Of the current 42 IRENA indicators and sub-indicators, 26 are proposed to be maintained, further developed and extended to the EU-25 (EU-27) and two more added. The indicators can be grouped in three categories according to their level of development.
A Memorandum of Understanding is being set up between Eurostat, DG AGRI, DG ENV, DG JRC and the EEA. A lead institution will be assigned for each indicator. All partners are collaborating in data collection and management, improving concepts and methodology and modelling.
3. EEA expectations; Gross Nutrient Balances and SOE (State of Environment) reporting
Nutrient balances are used to assess the effectiveness of AEI measures/policies and to indicate potential risk to water quality, but are strongly dependent upon area, time, data and method used. They are approximations. The cruder the spatial scale, the less value the balance has as an AEI. NUTS4/5 is a suitable resolution.
From the SOE perspective, surpluses from all sources are relevant, including areas of marginal land e.g. rough grazing that can be important regionally.
Harmonised and consistent approaches are needed, because it is often difficult to compare "like with like" with current estimates.
In the longer term, harmonisation should include an improved linkage between surpluses and water quality. This will require prediction of a range of factors – rainfall, soil type, topography – that together determine how much of the nutrient surplus is transferred to the nearest water body. Quantifying the relative proportion of the surplus that is "lost" to air and water would be of value from a policy perspective.
From the SOE perspective, balance calculations are ideally calculated at a river basin/hydrological scale. This, therefore, typically requires that information is re-aggregated from the administrative scale to the hydrological.
There are significant uncertainties in the concept of the surplus. The surplus is a relatively small difference between two very large values, the inputs and outputs of the balance. Inputs and outputs are often highly uncertain due to natural variability for example N in manure and imperfect data sources.
Potential methodological improvements:
- Better estimation of nutrient content of manure
- Quantifying N uptake in non-marketed fodder crops and grass
- Incorporation of gaseous losses (volatilisation and denitrification)
- Incorporation of the application of sewage sludge to land
- N content in irrigation water
- Balances of the marginal land (rough grazing etc.)
Comments:
- When it comes to hydrological scale, it would be easier and cheaper to measure N-contents from rivers and lakes than to calculate theoretical approximations of potential surplus.
- The need and quality of NUTS4/NUTS5 level information (and on a hydrological scale) was questioned by some of the countries. NUTS2 would be more realistic. On the other hand there are already methods to 1.) predict balances at a fine scale 2.) predict balances at a river basin scale and 3.) link balances with water quality (examples of all three were presented on day one of the workshop) and other attendees recognised a strong need for these approaches, as expressed following each of the presentations.
- The balance between what is feasible and what is needed should be found and the vision how to get there should be created.
4. Eurostat/OECD methodology for calculation GNB: background, development, principles,
Final results of the OECD N and P balances and technical problems encountered
OECD has developed a set of AEIs to describe, analyse and compare the current state and trends of environment in agriculture. The nutrient balances are one of the indicators, because they are politically relevant across the OECD countries. And they are also analytically sound (based on N & P cycles), measurable and relatively easy to interpret.
OECD calculates gross nutrient balances. Data is collected annually for all 30 OECD countries from national statistical agencies and in a few cases also Eurostat and FAO data is used. Coefficients are mainly national estimates and in few cases if there are no coefficients available, they are OECD estimates.
The methodology for the gross nutrient balances was chosen after a long process. It began with initial discussions between OECD and Eurostat experts in mid/late 1990s and proposal from Belgium. At this time a number of EU countries were already regularly calculating soil surface balances. A review of research literature reinforced the choice of the soil surface balance. After initial round of OECD balance estimates in Vol3 (2001), en expert peer review suggested OECD and Eurostat to move from "net" to "gross" balance calculations.
In the future OECD is going to develop networks and coordination with other member and non-member countries and international organisations, update balances regularly and seek greater use of balances in AEI modelling work.
OECD suggestions to improve the nutrient balances:
1. Extending national gross balance methodology to regional and river basin scale
2. Examining consistency in methods of nutrient coefficient calculations and improving coordination with other efforts, e.g. HELCOM (Baltic), OSPAR (North Sea), Gothenburg (ammonia), UNFCCC
3. Providing uncertainty estimates with balances
4. Including denitrification in balance
5. Examining how to reveal difference between dissolved and particulate P in soils in P balance
6. Ensuring data cover only agriculture (e.g. inorganic fertilisers)
7. Verifying that pig and poultry numbers reflect correctly annual production cycles
8. Checking for inconsistencies in agricultural land area data between different national and international sources
9. Checking the variation in coefficients across countries
10. Checking the volatilisation accuracy and double counting
11. Examining the uncertainty of nutrient uptake by harvested/grazed fodder crop and grass
12. Improve biological nitrogen fixation calculation in pasture
13. Cross-checking trends in balance results with trends in other indicators
14. Integrating balance results into models linking agric. and env. policies to nutrient balances and environmental outcomes
15. Establishing policy baselines, threshold levels and targets from which to monitor progress
16. Converting physical balances into monetary values, for national accounting and economic analysis
17. Examining potential for balance projections.
Comments:
- OECD suggestions to improve nutrient balances were considered very relevant. Especially the importance of harmonised and transparent methods of calculating coefficients and collecting the data were acknowledged as well as problems in estimating yields of grasslands and number of animals.
- Annual data for the balance calculations is collected from 1990-2004. The year 1990 is problematic for Eastern European countries if comparisons or time series are made, as the political changes of that time had an effect also on agriculture with production and use of inputs going down. However, the same base year is used because at that time the first environmental actions were started in other countries.
- An idea of "coefficient library" was established. The collection of different coefficients from different countries and regions would be very useful. The information of meta-data should also be included, so that methods of calculating coefficients were transparent.
5. JRC activities on Nitrogen Balances: methodological issues
a. Nitrogen Balances at NUTS II level: Combining Farm Gate and Soil Surface Approach
The study is part of the common work between JRC and University Bonn, with the purpose of linking of economic indicator calculators and bio-physical models for impact analysis of the CAP. Other area of cooperation between JRC and Bonn is a development of a spatial result layer (cropping shares, animal stocking densities, nutrient fate and CAP-pillar I subsidies) at 1x1 km grid resolution for EU-27.
Special attention is drawn to improvements of regional nitrogen balances, so the comparison of the data needs and calculation methods between farm gate and soil surface balances was made.
Comparison of data needs and surplus calculation of farm gate and soil surface balances:
Farm GateNational / Farm Gate
Regional / Soil Surface
National / Soil Surface
Regional
Surplus / imports
(mineral fertilizer, feed bought,
atmospheric deposition, bio. fixation)
– exports
(crop and animal products sold) / to soil
(mineral fertilizer, excrements,
atmospheric deposition, bio. fixation)
– from soil
(crop products removed)
Feed bought / X / X / ? / ?
Crop production
including fodder / - / - / X / X
Animal excretions / - / - / X / X
Crop products sold / X / X / - / -
Animal products sold / X / X / ? / ?
? = needed to define consistent excretions factors
Pros and cons of soil surface and farm gate balances and their combination:
Soil surface balances
+ provide information about manure applications, total nitrogen removals from soil,
and allow for estimates of ammonia emissions
+ don’t require data on animal products and feed use
- require nutrient excretion coefficients from animals and data on fodder yields, both
showing huge variations, are hard to measure and typically not available from
statistics and thus are possible error sources
Farm gate balances
+ provide a closed and consistent picture
+ are less dependent on assumptions (fodder yields, excretion coefficients)
- provide less information
- require data on feed imports, not found in statistics at regional level
Combination:
+ catches the advantages of both approaches
+ allows for additional analysis, e.g. about the efficiency of nitrogen use in feeding
- require data on fodder yields and feed imports
- require nutrient excretions defined as the difference between nitrogen input from
feed and nitrogen removals with animal products.
Challenges:
The main challenges at the regional level are the data gaps. Major input data of mineral fertiliser use (needed for both approaches), feed import (needed for farm gate balance) and fodder production (needed for soil surface balance) is not available.
The gaps have currently to be closed by making estimates or assumptions. Regional fodder yields are estimated from herd sizes of ruminants (energy needs of ruminants not covered by concentrates) in relation to fodder areas. Nutrient excretion factors per animal type are estimated as the difference between protein input from feed and protein removals with final and intermediate animal products. In the current study different data sources were used.
Time series of regional N-balances are derived for NUTS II regions based on readily available statistical information. In the calculations farm gate and soil surplus approaches were combined
b. Assessing nutrient pressure on water quality:
Spatialised European Nutrient Balance
The Fate project is a comprehensive approach to study the fate and impacts of nutrients on the European environment. It provides recommendations for policy support and develops methodologies to assess main processes responsible for nutrient pollution in waters.
Gross nutrient balances were calculated by using the OECD method and the data from Eurostat, EMEP, IFA and OECD. Balances and other information were combined with satellite pictures from Corinne Land Cover and FSS data. Comparison of the data from different sources was made during the study and some discrepancies were found, especially in the land use statistics.
Uncertainty in manure estimates was also noted. The coefficients depend on several factors which may vary from region to region, such as livestock breed, animal diet, housing system and farm type. Used coefficients were on national level. In addition, manure handling affects on its nutrient emissions and therefore should be taken account of.
6. Presentations of other nutrient balance approaches
a. Oene Oenema, Wageningen University (Alterra) – NL
"Calculating nutrient balances and nutrient losses at regional level
in EU-27 with MITERRA-EUROPE"
MITERRA-EUROPE is a simple and rapid tool for evaluation of N-emissions from agriculture at regional, country and EU-27 levels (N and P surpluses, ammonia, nitrous oxide, denitrification and methane emissions from animal housing, storage and soils, N leaching to water, interactions between N flows, N budget, soil organic matter and C sequestration).