Carbon dioxide, methane, and nitrous oxide fluxes in soil catena across the right bank of the Oka River (Moscow oblast)

The flux rates of carbon dioxide, methane, and nitrous oxide in the soils on autonomous, transitional, transitional-accumulative, and accumulative positions of a catena on the Oka River’s right bank (Moscow oblast) were assessed using the chamber method. The lowest rate of C-CO 2 emission (18.8–29.8 mg/m 2 per hour) was found for the gray forest soil in the autonomous position, and the highest rate (52.4–66.1 mg/m 2 per hour) was found for the alluvial meadow soil of the accumulative landscape. In the summer, the uptake of methane from the atmosphere exceeded its release from the soil at all the points of the catena (9–38 μg/m 2 per hour). The highest rate of the C-CH 4 uptake was observed for the soil in the transitional position. In the fall, the soils in the autonomous, transitional, and transitional-accumulative positions served as a sink of C-CH 4 , and the soil of the accumulative position was a source of methane emission. The rate of the N-N 2 O emission from the catena soils increased when going from the autonomous position to the accumulative one (0.41–11.2 μg/m 2 per hour). The spatial variation of the C-CO 2 , C-CH 4 , and N-N 2 O fluxes within the catena was 33, 172, and 138%, respectively. The upper (0- to 10-cm) soil layer made the major contribution to the emission of carbon dioxide. This soil layer was characterized by its C-CH 4 uptake, and the emission of methane was typical for the deeper (0- to 20-cm) layer. The layers deeper than 10 and 20 cm emitted more N-N 2 O than the surface layer.