The impact of desertification on carbon and nitrogen storage in the desert steppe ecosystem

Desertification is one of the most severe types of land degradation. This study quantified the impact of five different desertification regimes (potential (PD), light (LD), moderate (MD), severe (SD), and very severe (VSD)) on a desert steppe ecosystem in northern China, and investigated the changes in carbon (C) and nitrogen (N) storage in relation to land desertification. The C and N content in different stages of desertification were significantly different, while there was no obvious variation of C and N in different plant components as desertification progressed. Changes in soil C and N were not in accordance with plant succession, with the soil being more sensitive to desertification than the ground vegetation. When the VSD stage was compared with the PD stage, desertification resulted in the total C and N storage in plants decreasing by 97.3% and 96.8%, respectively, and in the 0–40 cm soil layer decreasing by 58.5%, and 76.0%, respectively. The highest C and N storage levels in the desert steppe ecosystem were 1291.93 g m−2, and 142.10 g m−2 in the PD stage, and the lowest levels were 505.14 and 33.41 g m−2 in the VSD stage. C and N losses through desertification were 786.79 and 108.69 g m−2, respectively. Therefore, it was confirmed that desertification results in soil degradation and seriously decreases soil potential productivity.