Author(s)

T. Dalgaard & A. Kyllingsbæk

Abstract

Developments in the nitrogen surplus and the fossil energy use in Danish agriculture during the 20" century T. Dalgaard & A. Kyllingsbak Danish Institute of Agricultural Sciences, Denmark Abstract This paper goes through the development in nitrogen imports, nitrogen exports, nitrogen surplus, and fossil energy use in Danish agriculture during the 20th century. The nitrogen export in the form of animal and vegetable products rose throughout the century. Until around 1950, atmospheric N derived by leguminous crops was the dominant nitrogen import, but then N fertilisers became dominant. Since 1983, the fertiliser import and the nitrogen surplus have dropped, and nitrogen imported in the form of concentrate fodders now equals the amount imported in the form of fertilisers. The fossil energy use generally follows the fertiliser use and, like the nitrogen surplus, has been in a continuous decline since the mid-eighties after an almost exponential growth period from 1945-1970. On the basis of the ni

Keywords