Rapid accumulation of carbon on severely eroded red soils through afforestation in subtropical China

Abstract

Recovery of carbon stocks after afforestation in degraded lands provides a management practice to mitigate rising atmospheric carbon dioxide concentrations, however carbon accumulation after afforestation of severely eroded lands is poorly understood. Large areas of the red soils in subtropical China suffer from severe erosion and have very low carbon density. We investigated above- and below-ground carbon pools in bare land on a severely eroded red soil (BL), a Pinus massoniana plantation that had been established on bare land in 1981(PM) and a nearby secondary forest (SF) in southeastern China. The ecosystem carbon pool in PM (130.1±7.2MgCha−1) was 10 times higher than in BL (13.0±1.3MgCha−1), and 22% lower than that in SF (166.7±7.0MgCha−1) (p<0.05). The above ground biomass carbon pool was 91.9±4.8MgCha−1 in PM, similar to 98.2±5.5MgCha−1 in SF. The soil organic carbon (SOC) pool (to 1m depth) in PM (38.2±3.4MgCha−1) was 2.9 times higher than that in BL (13.0±1.3Mg C ha–1), but was significantly lower than that in SF (68.5±2.5Mg C ha–1). About 70% of the organic C to 1m depth was stored in the top 40cm in the two forests. The storage of light fraction organic carbon (LFOC) at the 0–60cm depth in PM was significantly higher than that in BL, but not significantly different from that in SF. PM had significantly higher proportions of LFOC to SOC for all soil depths in comparison with BL and SF (p<0.05). The mean accumulation rates of ecosystem carbon pools, aboveground biomass carbon pools, and SOC pools in PM were 4.88±0.25, 3.83±0.16, and 1.05±0.09MgCha−1yr−1, respectively. Our results indicate that afforestation of severely eroded red soils with P. massoniana may be a successful forest management practice to achieve rapid carbon accumulation.