Soil Respiration and Carbon Sequestration: A Review

An increase in the concentration of carbon dioxide in the atmosphere is a trigger for the activation of all processes of the carbon cycle, including soil respiration (SR), because it causes not only the greenhouse effect of the atmosphere but also its fertilization. A consequence of fertilization is a tendency for the rise in the global net primary production (NPP) of photosynthesis and soil heterotrophic respiration (HR). An increase in the global terrestrial carbon sink has been accompanied by the rise in the CO2 concentration in the atmosphere. The global increase in HR is related to the global losses in soil organic carbon, which is confirmed by the models showing that the mean residence time (MRT) of organic carbon in soil pool has decreased by 4.4 years over the last century. To assess the level of C sequestration in soils, it is necessary to determine the balance between the soil HR and the amount of new soil C sink in the form of the net biome production (NBP) resistant to mineralization. The carbon sink into net ecosystem production (NEP) determines the short-term unsustainable carbon sequestration.