Abstract

Some results of monitoring (for the period from 1992 to 2005) related to transformations of carbon in agroecosystems of Baikal Siberia (Russia) characterized by unpolluted grey forest soils as well as the soils technogenically polluted with heavy metals are discussed with use the unique approach to integrated assessment of the agroecosystem’s functioning regime. The peculiarities of accumulation of carbon in soil microbial biomass and CO2 emission during the years differing in climate conditions are demonstrated. Analysis of formation of net-mineralized and (re)immobilized carbon is conducted, their ratio being used for the purpose of assessment of the level of influence upon the agroecosystem. The agroecosystems having technogenically polluted soils are characterized by processes of the soil microbial biomass reduction and by an obvious increase of CO2 emission into the atmosphere. Negative changes, which are bound up with carbon transformation, are intensified under unfavorable climate conditions. Intensification of processes of carbon net mineralization and, vice versa, lowering the intensity of processes related to carbon (re)immobilization (especially under the effect of soil pollution and climate changes) provoke instability of the agroecosystem and cause formation of a new regime of its functioning. eww141014dxn