Investigation of carbon sequestration content in astragalus rangelands in Gholestankoh of Khansar

In last decades، CO2 has become one of the most important glasshouse gases in which increased its concentrations in atmosphere and followed by global warming. The global warming may have negative impacts on the environment and natural ecosystems. Leniency of decreasing atmospheric carbon dioxide concentrations could be possible via carbon sequestration in biomass and soil organic matter of rangelands ecosystems in Iran and all around the world. Astragalus rangelands covering about 17 million hectare (10%) of Iran territory so could play much important role in carbon sequestration. In order to investigate the role and potential of Astragalus rangelands in carbon sequestration، a study was carried out in a key rangeland area covered by Astragalus brachycalex- Agropyron sp. in Gholestankoh of Khansar. The content of carbon in aboveground and underground biomass، litter carbon and soil organic carbon were determined. The results showed that the total carbon sequestration was 94. 90 ton/hectare and 94. 66 % of total carbon sequestration was soil organic carbon. The results of biomass carbon distribution showed that the carbon content in aerial biomass was higher than underground biomass. Correlation and stepwise regression analyses revealed that the content of carbon sequestration was positively related to Astragalus height and volume، aerial and underground biomass، total biomass، litter amount and soil organic carbon (SOC) content. It was concluded that the Astragalus rangelands have a tremendous potential to sequester carbon and the soil is the most important sink for organic carbon storage in Gholestankoh of Khansar rangeland.