Effect of simulated grazing on carbon storage of meadow grassland ecosystem in the north slope of Tianshan Mountain

In order to evaluate the potential effects of grazing intensity on organic carbon storage in the north slope of Tianshan Mountain meadow grassland, organic carbon storage in plant biomass, litter, root and soil were analysis in the steppes with four simulated grazing intensities (no grazing, light grazing, moderate grazing, heavy grazing) in 2012-2013. The results showed that the organic carbon storage in total, plant biomass and litter decreased with the increase of intensity. The carbon storage in root decreased in the following order: light grazing > no grazing > moderate grazing > heavy grazing and moderate grazing decreased by 42.25% and heavy grazing decreased by 72.41% compared with light grazing. The carbon storage in soil decreased in the following order: no grazing > moderate grazing > light grazing > heavy grazing. With the increase of soil depth, the carbon storage in roots gradually reduced and the changes of organic carbon density in soil varied which had an overall decline trend. The organic carbon storage in root and soil surfaced significantly. The carbon storage in the 0-20 cm soil layer account for 40% of the total carbon and the carbon storage decreased in the following order: soil > root > ground biomass. The organic carbon storage in soil was highest which account for more than 85% whereas the carbon storage in litter was the least.