Carbon isotope composition of soil and rangelands of Central Asia vegetation

Carbon isotope composition of plant and soil samples of Central Asia steppe rangelands (Buryatia, Mongolia, and Inner Mongolia, China) was studied. 8 I3C values of the investigated plant samples are low, ranging from -25.43 to -27.57%o, that indicates absolute predominance of plants with the C 3-type ofphotosynthesis in these communities. 8 I3C values of the soil organic matter in the upper horizons (0-20 cm) range from -27,867 to -I,24%. Down the soil horizon enrichment by I3C in I-2% is observed. 8 I3C isotopic composition of the investigated soils carbonate layers is presented by lower values (from -I4.53 to -7.85%) in comparison with organic matter. Variations of carbon isotopic composition of carbonates and organic matter are I6,I6-I7,89%, and they differ from the values, given in the literature - I,89-3,43%%.