Emissions of nitrous oxide and nitric oxide associated with the decomposition of arable crop residues on a sandy loam soil in Eastern England

Cumulative nitrous oxide emissions measured in a field experiment (g N2O-N.ha(-1), 19 August 1999-9 March 2000) for residues incorporated in the autumn on a sandy loam soil were significantly different: no residue (180) < barley (310) < peas (405); and, rotovate (248) < plough (349). For no residue and sugarbeet treatments incorporated in October, cumulative emissions were 713 and 268 g N2O-N.ha(-1), respectively, compared to 218 and 234 g N2O-N.ha(-1) for incorporation in January. The same trends were observed in 1998- 9, although emissions were greater (up to 1.9 kg N2O-N.ha(-1)). Emission factors for all the crop residues investigated were lower than the IPCC default value (1.25%). Emissions of NO, measured in 1999 2000 during the period immediately following cultivation were greater in August (0.99-1.55 g NO-N.ha(-1).d(-1)) compared to October (0.09-0.58) and January (0.10-0.22). Consistently lower NO emissions were obtained from ploughed compared to rotovated treatments.