Annual emission of carbon dioxide from soils of the southern taiga zone ofRussia

Data on the dynamics Of CO2 emission from soddy weakly podzolic and gray fo rest soils of the southern taiga zone have been obtained in the course of y ear-round field observations for 26 months. A modified method of determinin g the CO2 efflux from soils in the winter period is suggested. It is shown than annual dynamics of the CO2 emission from soils depends on particular w eather conditions. The curves of emission may have either one peak or sever al peaks (a serrate type of the curve) in the summer period. In the winter period (from November to April), the rate of soil respiration does not exce ed 100 mg C/(m(2) h), but it is always higher than 0 mg C/m(2) per h. In th e summer period (from May to October), the rate of soil respiration is 3.5 to 4.5 times higher than in the winter period. Annual efflux of CO2 from th e soils of the southern taiga zone varies from 2.65 to 11.5 t C/ha dependin g on the weather conditions of the year and the particular types of soils a nd phytocenoses. The contribution of winter respiration to annual respirati on constitutes 21-27% in the soils under natural cenoses and 12-14% in the soils under agrocenoses. The most significant influence on the CO2 emission is exerted by the soil temperature. In particular, the respiration intensi ty of soddy-podzolic soils is very sensitive to temperature fluctuations.