The effect of land use and different soil tillage systems on CH4 oxidation was tested in a laboratory incubation study. Intact soil cores were collected from the topsoil (0â??12â??cm) of a field site with ploughed, direct-drilled and set-aside treatments, and from an adjacent undisturbed forest site. CH4 oxidation rates were 4.5 to 11 times higher in the direct-drilled than in the continuously ploughed treatment, in the set-aside soil they were intermediate. The oxidation rates in the forest soil were 11 times the highest rate measured at the field site, pointing to a distinct land use effect. Vertical profiles of CH4 oxidation activity revealed a very clear zonation in all treatments. CH4 oxidation increased significantly below the plough layer (0â??25â??cm), and showed a subsurface maximum under direct-drilling (5â??15â??cm) and under forest (5â??10â??cm). The vertical zonation under set-aside was comparable to that under ploughing. Generally, the maximum CH4 oxidizing activity was in the zone nearest to the soil surface, unless various constraints prevented this.
