Abstract
Afforestation has been suggested as an ecosystem restoration approach for mitigating carbon loss after land-use changes. Understanding soil organic carbon (SOC) by conversion from abandoned aquaculture ponds to afforestation is crucial. We investigated soil organic carbon from a poplar (Populus spp., 19 years after planting, PS) plantation site with ditches and a pond cypress (Taxodium spp., 4 years after planting, TS) forest with non-ditches on abandoned aquaculture ponds in East China. Soils with three layers (0–10, 10–20, and 20–30 cm) were sampled. The results showed that there were no significant differences in SOC between soil layers for PS with 5.09 ± 2.27, 2.60 ± 0.59, and 6.94 ± 3.56 g kg−1, respectively; compared to TS with 4.16 ± 1.48, 3.31 ± 0.88, and 4.32 ± 1.41 g kg−1, respectively. However, significant differences of soil water contents (SWC) and bulk density (BD) were found between two sampling sites, and both BD and pH had significant negative relationships with SOC. It is suggested that low SWC resulting from the ditch could lead to a potential risk of SOC decomposition and offset the soil carbon sink by afforestation. Additionally, pond cypress might be a preferred species selection for ecosystem restoration in both soil carbon sink and landscape aesthetics.
•Soil organic carbon of 19-year poplar has no difference from 4-years pond cypress.•Low soil water contents at poplar site with ditch could offset soil carbon sequence.•Pond cypress might become preferred species selection for ecosystem restoration.
