Effects of various nitrogen fertilisers on nitrous oxide emissions from arable soils

Abstract

The main cause for increased nitrous oxide (N 2 O) emission from agricultural soils is nitrogen fertilisation. In the present investigation the effect of the form of N fertilisers on N 2 O emission was studied. Emission of N 2 O was measured in a field experiment using the closed chamber method. 60 kg N ha −1 were applied on arable soil to oats (Avena sativa) in the form of calcium nitrate, ammonium sulphate, ammonium sulphate in combination with the nitrification inhibitor dicyandiamide and calcium ammonium nitrate. N 2 O emissions increased within two days after fertilisation. After 6 to 8 days, emissions decreased again to the levels before fertilisation. The rapid decrease of N 2 O emissions one week after fertilisation was associated with a decrease in the content of mineral N in the soil. Emissions were generally below 1% of the applied N, presumably because of the fast removal of mineral N from the soil by plant uptake and/or immobilisation. N 2 O emission was highest after fertilisation with calcium ammonium nitrate and was nearly prevented by fertilisation with ammonium sulphate in combination with nitrification inhibitor. The present results suggest that the amount of N fertiliser-induced N 2 O emission is strongly dependent on the form of N fertiliser and may be effectively reduced by fertilisation of ammonium-N in combination with a nitrification inhibitor.