Nitrogen management on Danish livestock frams and the related legislation

Abstract

The use of mineral nitrogen (N) fertilisers in Danish livestock production systems has increased considerably over this century. Nitrogen losses have increased as N inputs have increased and there has been a lowering of the efficiency with which N is utilized in livestock production. This has lead to an increase in atmospheric pollution by ammonia (NH3) and to aquatic pollution by nitrate (NO3). Leaching of NO3 may cause an enrichment of NO3 in aquifers, which is considered a serious environmental problem, because groundwater is used for drinking water without any pre-treatment. Deposition of NH3 is harmful to a number of natural ecosystems. Much of this pollution has arisen from animal manure because it is not used efficiently for plant production. The principle behind Danish legislation aims to reduce leaching losses of NO3 and volatilization of NH3 by improving the utilisation of N in manure. In this paper we describe trends in N use during this century and the legislation implemented to reduce its loss are described.