Differences in Farm Nitrogen Indicators at Farm Level in European Case Studies

Nitrogen (N) budgets at farm gate level account for all N inputs and outputs in a particular farm. Indicators derived from the N budgets are crucial for characterising farm performance, due to the important role of N in food production and environmental sustainability. However, comparison among farm N indicators from different farms, farm types and regions requires conducting systematic monitoring of N budgets following a common and solid approach. Because of this, the EU N Expert Panel (EUNEP) developed a guidance document to estimate N inputs and outputs at the farm gate and calculate the N indicators.

M. Quemada1, L. Lassaletta1, L.S. Jensen6, O. Godinot5, F. Brentrup2, C. Buckley3, S. Foray4, S. K. Hvid7, J. Oenema8, K. G. Richards3, T. Haniotis9, O. Oenema8

1 Department Agricultural Production/CEIGRAM, Universidad Politécnica de Madrid, Spain.

2 Yara International, Research Centre Hanninghof, Dülmen, Germany.

3 Teagasc, Ireland.

4 Institut de l’élevage, département techniques d’élevage et environnement, F-35652 Le Rheu, France.

5 SAS, Agrocampus Ouest, INRA, F-35042 Rennes, France.

6 University of Copenhagen, Denmark.

7 SEGES, Denmark.

8 Wageningen University, PO Box 47, Wageningen, The Netherlands.

9 DG Agriculture, European Commission, Brussels.

28 pages, 12 figures, 1 table, 39 references.

In this study, the EUNEP approach was applied to 1,240 farms from various case studies in Europe, with the aim of increasing understanding of the factors that contribute to differences in N indicators at the farm level and to derive possible target values. Farm level data were collected from six countries located in five different environmental zones in Europe: Atlantic Central (France, Ireland, The Netherlands), Atlantic North (Denmark, Germany), Continental (Germany), Mediterranean North (Spain) and Mediterranean South (Spain). The N budgets were calculated for each farm, and the data were analysed to calculate three related indicators: Nitrogen use efficiency (NUE), N output and N surplus.

The results show remarkable variations in N indicators across Europe. Arable farms had the lowest mean N input and N surplus and the highest mean N output and NUE, whereas animal farms had the highest mean N input and N surplus, and the lowest mean N output and NUE. Median NUE was 61% for arable farms, 28% for dairy and 43% for pig farms. Externalisation had a large effect on animal farm N indicators, and the results highlight the need for introducing adjusting factors when calculating and interpreting the farm balance. After accounting for externalisation, median NUE decreased to 19% for dairy farms and 23% for pig farms.

Therefore, several options were proposed to better consider feed production and manure management in N indicators calculations. Overall, the differences in NUE between farms were mainly related to differences in farm type, management (production intensity and practices) and probably also soil and climate conditions. Nitrogen indicator targets for specific farm types and linkages with agricultural or environmental policy may contribute to optimising NUE and reducing N surplus at the farm level.