THE RESERVES AND LOSSES OF ORGANIC-CARBON IN THE SOILS OF SIBERIA

The organic carbon database for the soils of Siberia has been develope d. It includes data on humus content and bulk density determined in 58 50 and 2300 soil pits, respectively. On the basis of these data we cal culated the reserve of organic carbon in Siberian soils. It constitute s 199 x 10(9) t, or 13.1% of the total world pool. During the last cen tury, the total loss of organic carbon from the plowed soils in Wester n Siberia amounted to 11.2 x 10(8) t, or 29% of the initial content. T he losses induced by erosion and deflation reached 1.1 x 10(8) t, or 1 0% of the total loss. With the passage of time, the loss induced by mi neralization decreases, whereas the soil erosion loss increases. Bog e cosystems of Western Siberia serve as sinks for carbon dioxide owing t o the active accumulation of peat. Within the past century, the amount of carbon sequestered in peat deposits of Western Siberia has reached approximately 15 x 10(8) t, i.e., it is 1.5 times higher than the los s of organic carbon from the plowed soils within the same period.