Abstract
The release of CO2 from the snow surface in winter and the soil surface in summer was directly or indirectly measured in three different soil types (peat, sand and clay) in agricultural ecosystems in Finland. The closed chamber (CC) method was used for the direct and Pick’s diffusion model (DM) method for the indirect measurements. The winter soil temperatures at 2-cm depth were between 0 and 1°C for each soil type. The concentration of CO2 within the snowpack increased linearly with snow depth. The average fluxes of CO2 calculated from the gradients of CO2 concentration in the snow using the DM method ranged from 10 to 27 mg CO2 m2h-1 and with the CC method from 18 to 27 mg CO2 m2h-1. These results suggest that the snow insulates the soil thermally, allowing CO2 production to continue at soil temperatures slightly above freezing in the winter. Carbon dioxide formed in the soil can move across the snowpack up to the atmosphere. The winter/summer ratio of CO2 evolution was estimated to exceed 4%. Therefore, the snow-covered crop soil served as a source of CO2 in winter, and CO2 evolution constitutes an important part of the annual CO2 budget in snowy regions.
Highlights
The release of C0 2 from the snow surface in winter and the soil surface in summer was directly or indirectly measured in three different soil types in agricultural ecosystems in Finland
These results suggest that the snow insulates the soil thermally, allowing C0 2 production to continue at soil temperatures slightly above freezing in the winter
Budgets assume that microorganisms and plant roots in snow-covered soils stop respiring and so there is no evolution of C02 from the snow surface when soil temperatures drop to around O°C
Summary
The release of C0 2 from the snow surface in winter and the soil surface in summer was directly or indirectly measured in three different soil types (peat, sand and clay) in agricultural ecosystems in Finland. The winter soil temperatures at 2-cm depth were between 0 and I°C for each soil type. Snow using the DM method ranged from 10 to 27 mg C0 2 nr 2 h and with the CC method from 18 to 27 mg C0 2 These results suggest that the snow insulates the soil thermally, allowing C0 2 production to continue at soil temperatures slightly above freezing in the winter. Budgets assume that microorganisms and plant roots in snow-covered soils stop respiring and so there is no evolution of C02 from the snow surface when soil temperatures drop to around O°C
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have