[Dynamics of carbon and nitrogen storages in plant-soil system during desertification process in Horqin sandy land]

Organic carbon and nitrogen storages in plant-soil system were measured at different desertification stages (potential, light, moderate, severe, and most-severe) in Horqin sandy land. From potential desertification to light, moderate, severe, and most-severe desertification, total biomass (aboveground and belowground) carbon storages decrease by 26.4%, 51.0%, 79.0%, and 91.0%, respectively, while total biomass nitrogen storages decrease by 33.6%, 66.9%, 87.4%, and 93.2%, soil organic carbon storages by 52.2%, 75.9%, 87.0% , and 90.1%, and soil nitrogen storages by 43.5%, 71.0%, 81.3%, and 82.7%, respectively. The carbon and nitrogen storages in plant-soil system are in the order: potential (C: 5 266 g x m(-2) and N: 534 g m(-2)) >light (C: 2619 g x m(-2) and N: 303 g x m(-2)) >moderate (C: 1368 g x m(-2) and N: 156 g x m(-2)) >severe (C: 715 g x m(-2) and N: 99 g x m(-2))>most severe (C: 517 g x x m(-2) and N: 91 g x m(-2)). The biomass carbon and nitrogen storages decline more rapidly at later desertification stage (from severe to most-severe) than initial stage (from potential to light), while soil carbon and nitrogen decline more rapidly at initial stage. There is a greater proportional decline in soil carbon than in nitrogen during desertification process. The biomass nitrogen storages decline more rapidly than carbon at initial stage, however, the case is reverse at later stage.