Influence of slurry and mineral fertiliser application techniques on N2O and CH4 fluxes from a barley field in southern Finland

The application of livestock manure and mineral fertilisers is an important source of greenhouse gases in agriculture. Currently there is a lack of knowledge about the effects of different application techniques on nitrous oxide (N2O) and methane (CH4) fluxes from agricultural soils. In this study, the effects of different application techniques on emissions of these gases from a spring barley (Hordeum vulgare L.) field were compared. The study was conducted in Vihti, southern Finland. During a 5-month period, slurry injection combined with sowing produced the most N2O, with a cumulative N2O flux (+/- S.D.) of 1100 +/- 293 g N2O-N ha(-1). When slurry was injected and mineral fertiliser placed in combination with sowing, the cumulative N2O emissions were 660 +/- 122 g N2O-N ha(-1). Cumulative NO flux was 400 64 g N2O-N ha(-1) from slurry incorporated I h after band spreading followed by combined placement of mineral fertiliser and sowing. NO emissions were the lowest (290 +/- 47 g N2O-N ha(-1)) when mineral fertiliser without slurry was placed in combination with sowing. The proportion of applied N lost as N2O during the 5-month period was highest (0.7%) in the treatment where only slurry was injected, and lowest (0.3%) when mineral fertiliser was placed. Cumulative CH4 fluxes ranged from -290 to 50 g CH4-C ha(-1) in the treatments and no significant effect of the application technique was detected. The results suggest that separate emission factors should be developed for N2O emissions resulting from different application techniques. (c) 2006 Elsevier B.V. All rights reserved.