The Stable Carbon Isotope Characteristics Of Plants, Soil, Faeces And Hairs Of Grazing Sheep And Cattle In Inner Mongolia Desert Steppe

The experiment was conducted to study the stable carbon isotope characteristics of plants,soils, the faeces and hairs of grazing livestocks (sheep and cattle) by applying the stable carbon isotope techniques in desert steppe of Inner Mongolia (Xilamuren and Siziwangqi) from 2014 to 2015. The results were shown as follows:1.There were 3 species belong to C4 plant in all 35 species measured, and others were C3 plant. The δ13C values of C4 plant were significantly higher than C3 plant. And the average δ13C values of C3 and C4 plant were-26.60‰ and-15.06%o,respectively. The 653C values of different organs in plants was ranked in this order:δ13Croot>513Cstem>δ13Cleaf, except for Stipa krylovi7.and Stipa breviflora.2.The long-term heavy grazing significantly decreased the δ13C values of 6 species of C3 plant and increased the δ13C value of Kochia prostrate, whereas did not affect the 813C values of Cleistogenes songorica, which indicated that effects of grazing on different types of photosynthetic pathway plants were different. Meanwhile, the δ13C values of soils(0-15cm) were in the grazed area was significantly higher than that in un-grazed area, especially in 0-5cm layer, which showed that grazing could greatly affect the organic matter decomposition of the soil surface.3.Although the δ13C values were different between the faeces and hairs in sheep and cattle and their diets, but we still can calculate the composition of diets though the relationship between the faeces and hairs of cattle and sheep and their diets, and get a better understanding on the diets of sheep and cattle.