Effects of managements on soil organic carbon of grassland in China

Based on the statistic data related to the grassland management and soil organic carbon in China Soil Series，Rangeland Resources of China， China periodical magazine website and database in foreign languages, the changing amount of soil organic carbon in surface layer of grassland under different managements was analyzed. The result indicated that the yearly change of the soil organic carbon in each type of grassland varied under the different grassland managements because of the different soil textures and climatic conditions. The range of variation was the largest under the different management in alpine meadow (-5.62 to 1.26 t/hm2) while the variation was the smallest in temperate desert steppe (-0.85 to 0.68 t/hm2). The variation ranges for other types of grassland were -3.74 to 0.68 t/hm2 in temperate meadow, -3.62 to 0.04 t/hm2 in alpine steppe, -2.4 to 1.07 t/hm2 in temperate steppe and -1.94 to 0.64 t/hm2 in shrubby grassland respectively. Meanwhile the Meta analysis method was used to estimate the yearly changing amount of soil carbon under different management patterns and the result indicated that the order of soil organic carbon amount was overgrazing (-2.34 t/hm2)heavy grazing (-1.52 t/hm2) light grazing (-0.54 t/hm2) medium grazing (-0.49 t/hm2), while the yearly increasing amount of soil organic carbon was the highest in the resowed grassland (0.90 t/hm2), followed by enclosure grassland (0.48 t/hm2) and grazing forbidden grassland (0.19 t/hm2). It could be concluded that the improper managements such as over grazing would negatively influence the accumulation of soil organic carbon while the resowing and enclosure would help the accumulation of soil organic carbon.