02049naa a2200157 a 450000100080000000500110000800800410001910000140006024500730007426000090014752014570015665000110161365000190162465000240164377302240166721053612019-02-01       2005    bl uuuu     u00u1 u    #d1 aLANDI, A.  aConversion of organic to inorganic carbon in a cold semiarid region.  c2005  aThe pedosphere plays a significant role in influencing the gaseous composition of the atmosphere especially carbon dioxide. Soil organic carbon (SOC) and soil inorganic carbon (SIC) are the two major C pools in the pedosphere, and are closely linked to the biosphere and atmosphere. With respect to the C cycling in the soil, it is important to know how much atmospheric C02 is sequestered as pedogenic carbonate (PC) and how much SIC is derived from SOC during that process? Stable isotope geochemistry was used to determine the amount and accumulation rate of PC and organic C, together with I3CI 2C ratio of soil organic C, in a series of zonal soils representing gradients of environment and time in Saskatchewan, Canada. Results showed that the amount and rate of organic C to 1.2 m depth increased from south to north in prairie lands, in response to increasing precipitation. The amount and rate of PC accumulation also increased in the same direction. Using the net primary production (NPP) of carbon for above ground and belowground data and rate of carbon accumulation as organic C, it was calculated that about 0.32 % of NPP carbon can be accumulated as organic C and about 0.46 % as inorganic C. This shows that in the long term, PC can play an important role in carbon cycle, as it accounts for larger sequestration of carbon than organic matter. Taking organic and inorganic C together, less than 1 % NPP C can be accumulated in the soil.  aCarbon  aSemiarid soils  aSoil organic carbon  tIn: INTERNATIONAL CONFERENCE ON THE DEVELOPMENT OF DRYLANDS, 7., 2003, Tehran, Iran. Sustainable development and management of drylands in the twenty-first century; proceedings. Aleppo, Syria: ICARDA, c2005. p. 154-159.