METHANE OXIDATION IN SOILS WITH DIFFERENT TEXTURES AND LAND-USE

Intact core samples from soils with different textures and land use we re tested for their capacity to oxidise methane. The soil cores were t aken from arable land, grassland and forest. It was found that coarse textured soils (6.74-16.38 mu g CH4 m(-2) h(-1)) showed a higher metha ne uptake rate than fine textured soils (4.66-5.34 mu g CH4 m(-2) h(-1 )). Increasing soil tortuosity was thought to reduce the methane oxida tion rate in fine textured soils. The oxidation rate of forest soils ( 16.32-16.38 mu g CH4 m(-2) h(-1)), even with a pH below 4.5, was very pronounced and higher than arable land (11.40-14.47 mu g CH4 m(-2) h(- 1)) and grassland (6.74-9.30 mu g CH4 m(-2) h(-1)). Within the same te xtural class arable land showed a faster methane uptake rate than gras sland. In grassland with a fine texture, even methane production was o bserved. Nitrogen availability and turnover in these land use systems were thought to cause the different oxidation rates. Decreasing the mo isture content slowed down the oxidation rate in all soils. This could be caused by an increased N turnover and a starvation of the methanot rophic bacteria.