Organic carbon stocks and erosion in the soils of Guangdong, South China.

Soil organic carbon (SOC) storage and erosion in South China at the regional scale in the past decades remains far from being understood. This paper calculated the SOC density, storage and erosion in 14 soil classes in Guangdong Province, South China, based on statistical data from the soil survey and soil erosion survey of Guangdong, which was performed in the 1990s. The purpose of this study is to understand the relationships between soil classes and SOC erosion at the regional scale. The results indicated that the SOC density in the soils of Guangdong varied from 12.7 to 144.9 Mg ha over the entire profile and from 12.6 to 68.4 Mg ha in the top 20-cm soil layer. The average area-weighted SOC density in the topsoil (0-20 cm) and the entire profile was 32 ± 3 and 86 ± 4 Mg ha, respectively. The total SOC storage was 1.27 ± 0.06 Pg, with 35.6 % (0.46 ± 0.04 Pg) located in the topsoil. The average area-weighted strength of the SOC erosion in the 1990s was 20.6 ± 0.8 Mg km year. The results indicated that SOC erosion was strongly related to soil class. [ABSTRACT FROM AUTHOR]