Effects of drainage on soil organic carbon stock in the Zoige peatlands,eastern Qinghai-Tibetan Plateau

Peatlands play a significant role in the global carbon cycle. They have been considered an important sink of carbon and account for 25%-43% global soil organic carbon stocks. Drainage has led to large losses of soil organic carbon in peatlands. However,few studies have investigated the impacts of drainage on soil organic carbon stocks in Zoige peatlands on the Qinghai-Tibetan Plateau. To reveal the spatial distribution characteristics of soil organic carbon stocks under different drainage regimes,and to provide more reliable soil organic carbon stock estimations,we surveyed the soil organic carbon stocks along a distance gradient from the ditches in Zoige peatlands. Soil bulk density and soil organic carbon stocks at different soil depths were investigated in two un-drained sites and three drained sites 130 m( D130),200 m( D200),and 300 m( D300) away from the ditch. The soil organic carbon stocks ranged from 816.53-1030.88 t C /hm~2 in un-drained sites,with a mean of( 923.71+ or -107.18) t C / hm~2. The soil