Carbon monoxide, hydrogen, and methane uptake by soils in a temperate arable field and a forest

CO, H-2 and CH4 uptake by the soil of an arable field and a forest soil (360 m apart) was measured by a closed-chamber method in temperate Japan for about 1 year. CO production observed was exponentially dependent on top soil temperature. CO production was greater in the forest soil than in the soil of the arable field at the same soil temperature. 2 (Gross) CO, H-2 and CH4 deposition velocities ranged from 0 to 7X 10(-2), from 0 to 9X 10(-2) and from 0.05 to 0.1X 10(-2) cm s(-1) in the arable field and from 1.5 to 4.5X 10(-2), 5 to 8X 10(-2) and from 0.3 to 0.6X 10(-2) cm s(-1) in the forest, respectively. Variations in the deposition velocities were smaller in the forest than in the arable field and corresponded to variations in soil moisture in the top soil. Seasonal trends caused by the variation in temperature were observed only for CH4 deposition, reflecting the clear dependence on soil temperature. Application of dead plant material to the arable field led to acceleration of CO and H-2 deposition onto the soil, The deposition velocities of CO and H-2 were positively correlated (n=36, R-2* = 0.881, p<0.0001; R-2* is the coefficient of determination adjusted by, degrees of freedom) in the arable field and (n=37, R-2* = 0.308, p<0.0001) in the forest, suggesting diffusion control on their deposition velocities.