SOIL RESPIRATION AND CARBON BALANCE OF GRAY FOREST SOILS AS AFFECTED BY LAND-USE

Soil respiration was measured by closed chamber and gradient methods i n soils under forest, sown meadow and crops. Annual total soil respira tion determined with the closed chamber method ranged from 180 to 642 g CO2-C m(-2) year(-1) and from 145 to 382 g CO2-C m(-2) year(-1) dete rmined with the CO2 profile method. Soil respiration increased in the order: cropland < sown meadow < forest. The C balance calculated as th e difference between net primary production (sink) and respiration of heterotrophs (source) suggested an equilibrium between the input and o utput of C in the cropland, and sequestration of 135 and 387 g CO2-C m (-2) year(-1) in the forest and meadow, respectively.