Difference in Soil Methane (CH4) and Nitrous Oxide (N2O) Fluxes from Bioenergy Crops SRC Willow and SRF Scots Pine Compared with Adjacent Arable and Fallow in a Temperate Climate

Abstract

Soil greenhouse gas (GHG) fluxes of methane (CH4) and nitrous oxide (N2O) were measured over a 2-year period from several land use systems on adjacent sites under the same soil and climatic conditions to assess the influence of the transition from arable agricultural (barley) and fallow to perennial bioenergy crops short rotation coppice (SRC) willow (Salix spp.) and short rotation forest (SRF) Scots pine (Pinus sylvestris). There were no significant differences between CH4 and N2O fluxes measured from the SRC, SRF and fallow, but the arable agricultural site showed an order of magnitude higher N2O emissions compared with the others. Fertiliser application to the arable crop was the major factor influencing N2O emissions, and both air and soil temperature showed no significant effects on fluxes between the different land use systems. Soil moisture was significantly different from the arable crop, showing a greater range than from SRF and SRC. Hence, these bioenergy crops might be viable options for water-stressed areas.