Dynamics of soil carbon storage in Stipa breviflora desert steppe under different grazing systems

In the present study, the change characteristics of soil carbon storage under different grazing systems were studied to provide suggestion for grassland reasonable usage in carbon storage perspective because grazing system is the main artificial factor of soil carbon storage. The variations of organic carbon storage in the 0－30 cm soil layers were studied from May to October with three different grazing systems which were continuous grazing (CG), rotational grazing (RG) and non-grazing (NG) in Stipa breviflora desert steppe in Inner Mongolia. The soil organic carbon storage in 0 to 30 cm soil layers of CG were significantly lower than that of RG and NG (P0.05), however, there were no significant difference between RG and NG (P0.05). There were two carbon sources progresses and one carbon sink progress in 0 to 30 cm soil layers of CG in growing season, there were one carbon sources and one carbon sink progress in that of RG and there was one carbon sources progress in that of NG. The soils from all the sampling sites were identified as carbon source with net increase carbon storage. The carbon source of CG, RG and NG were -0.75, -0.45 and -0.32 kg·m-2, respectively. The comprehensive analysis suggested that the reasonable grazing system contributed to soil carbon accumulation and could reduce carbon emission and the order was NGRGCG.