Urease and nitrification inhibitors for climate and environmental protection: opportunity or risk? / by Anne Biewald, Urs Dippon-Deißler, Sondra Klitzke, Lisa Noll (German Environment Agency, Dessau-Roßlau), Andreas Pacholski (Thünen Institute, Braunschweig) ; in collaboration with Gesa Amelung, Franziska Kaßner, Ivo Schliebner, Frauke Stock (German Environment Agency, Dessau-Roßlau) ; edited by: Section I 1.4 Economic and Social Environmental Issues, Socio-Ecological Structural Change, Sustainable Consumption - Anne Biewald

Abstract

Urease and nitrification inhibitors are increasingly being used in agriculture to reduce fertilization derived ammonia, nitrous oxide emissions and the leaching of nitrate. Their use is expected to become even more important after 2030, when the agricultural sector will be obliged to make a significant contribution to the ambitious European and national climate targets. Our estimates for extensive usage of inhibitors in the EU show that their use could reduce agricultural ammonia emissions by up to nine per cent and greenhouse gas emissions by up to five per cent. However, the potential risks of large-scale application of inhibitors to human health and the environment have not yet been sufficiently investigated and understood. The specific efficacy of different urease and nitrification inhibitors, for example at different sites or over longer periods of time, has also not yet been sufficiently clarified. In addition, the data on the fate of the substances in the environment is patchy and sometimes contradictory. These uncertainties have so far only been partially taken into account in the legal regulations at EU and national level. This can be seen, for example, by the fact that five of the eleven inhibitor compounds available on the German market would, due to their toxicity, very probably not be approvable under the EU Plant Protection Products Regulation. This points to a regulation gap, as the method of application in the open environment, the quantities used and, in some cases, the target effect are identical for inhibitors and plant protection products. In addition, the inhibitors can be approved for the market via two different and sometimes non-transparent legal regulations. This makes it difficult for the public to understand the risk of using inhibitors. Large-scale use of inhibitors can therefore by the German Environment Agency (UBA) only be recommended if a standardised European regulation on authorisation ensures that the protection of human health and the environment is ensured in the long run and that the precautionary principle specified in the Treaty on the Functioning of the European Union is thus fulfilled. An obvious solution would be the creation of an EU regulation with an authorisation and approval procedure similar to that of the EU Plant Protection Regulation or the integration of inhibitors into the EU Plant Protection Regulation.