CO sub(2) emission from the surface of dark gray forest soils of the forest steppe and sandy soddy-podzolic soils of the southern taiga

Studies performed on dark gray loamy forest soils in an oak forest in the southern forest steppe and on sandy soddy-podzolic soil in a pine forest in the southern taiga showed that the annual emission of CO sub(2) from the soil surface in the pine forest was 16.3 t CO sub(2)/ha, including 10.1 t CO sub(2)/ha due to root respiration and 6.2 t CO sub(2)/ha due to soil microbial respiration. In the southern forest steppe, the corresponding values were 17.8 t CO sub(2)/ha due to root respiration at the optimum water content (20%) and 28.3 t CO sub(2)/ha due to soil microbial respiration. With the insufficient soil water content (12.5%), 10.3 and 17.8 t CO sub(2)/ha were due to root respiration and soil microbial respiration, respectively. Under strong drought conditions (water content of 10%), the emission of CO sub(2) decreased to 8.2 and 16.3 t/ha due to root respiration and soil microbial respiration, respectively.