An evaluation of topsoil carbon storage in Chinese deserts

Deserts are important components of the terrestrial ecosystem, and significantly affect the terrestrial carbon cycle. However, their carbon storage is poorly understood. To evaluate the topsoil carbon storage in Chinese deserts, we sys-tematically collected topsoil samples (to a depth of 10 cm) from 12 deserts in northern China and analyzed their or-ganic carbon storage. We used partial correlation and boosted regression tree (BRT) analysis to analyze the factors influencing the spatial distribution of soil organic carbon density based on climate, vegetation, soil grain-size distribu-tion, and element geochemistry. The total organic carbon pool of Chinese deserts was 4.83 x 108 t, the mean soil or-ganic carbon density was 1.37 +/- 0.18 kg C m-2, and the mean turnover time was 16.50 +/- 2.66 yr. With the largest area, the Taklimakan Desert had the highest topsoil organic carbon storage (1.77 x 108 t). The organic carbon density was high in the east and low in the west, whereas the turnover time showed the opposite trend. The soil organic carbon density was >2 kg C m-2 in the four sandy lands in the eastern region, and was greater than the values for the eight deserts (0.72 to 1.22 kg C m-2). Grain-size (i.e., the silt and clay contents) had the strongest influence on the organic carbon density in Chinese deserts, followed by element geochemistry. Precipitation was the main climatic factor that affected the distribution of organic carbon density in the deserts. Based on climate and vegetation cover trends during the past 20 years, Chinese deserts have a high potential for future organic carbon sequestration.

Automated summary

Through analyzing soil samples from 12 deserts in China, it was found that Chinese deserts have a significant amount of organic carbon storage, with the Taklimakan Desert having the highest storage. Soil grain-size and element geochemistry are the main factors influencing organic carbon density in Chinese deserts, while precipitation is the main climatic factor affecting its distribution. Based on climate and vegetation cover trends in the past 20 years, Chinese deserts have a high potential for future organic carbon sequestration.