Keywords: Greenhouse gases, GHG, emission factors, nitrogen fertilisers, nitrous oxide, N2O, CO2, agriculture, food production, efficient energy use, EU targets, EFMA.
The use of mineral fertiliser is an essential component of sustainable agriculture. Mineral fertilisers are applied in order to balance the gap between the nutrients required for optimal crop development and the nutrients supplied by the soil and by available organic sources. On the other hand, the fertiliser industry is a consumer of energy and an emitter of carbon dioxide (CO2) and other greenhouse gases (GHG). However, the GHG emissions during the production of the fertilisers should not be evaluated without considering the benefits from fertilisers in agricultural production. This paper therefore investigates the climate change impacts of fertilisers including their production, transportation and use. The energy balance of crop production is positive, because it is the nature of crop production to convert solar energy into crop biomass. Appropriate use of mineral fertiliser further improves this positive energy balance. Depending on the crop, fertiliser application helps to fix 10 to 15 times more energy than the production, transportation and application of the fertiliser consumes. If the energy contained in the biomass produced is used as biofuel, it replaces fossil fuels and thereby mitigates CO2 emissions. The responsible production and use of mineral fertilisers in agriculture should be considered not only as an essential part of the global production of food, but also as part of the solution for climate change problems. The paper will address the impact of fertilisers on climate change and how new production technology and optimum fertiliser application lead to significant improvements in the GHG balance of crop production.
The paper presents life cycle assessment (LCA) calculations of the GHG emissions associated with the production and use of different fertiliser types and the primary energy consumption used in their production. These data, which are all from referenced sources, will contribute to the public EU database for LCA studies: http://lca.jrc.ec.europa.eu.
Frank Brentrup, Yara International ASA, Research Centre Hanninghof, Hanninghof 35, D-48249 Dülmen, Germany.
Christian Pallière, European Fertilizer Manufacturers Association (EFMA), Avenue E Van Nieuwenhuyse 6, B-1160, Brussels, Belgium.
25 pages, 14 figures, 4 tables, 20 references.