The type of soil amendment during farming affects the restorability of peatlands

Peatlands have declined dramatically in the past century due to agricultural cultivation. The main goal of this study was to assess the impact of soil amendment during farming on the restorability of peatlands. We compared the soil seed banks between the natural peatland and farmed peatlands with two soil amendment types (sand-amended and silt-amended) in the Changbai Mountains, China. We found that the seed density and species richness in silt-amended peatland were higher than the natural peatland, and they were the lowest in the sand-amended peatland. Carex species are foundational species of these wetlands and these dominated both in standing vegetation and soil seed banks of the natural peatland. Carex spp. occurred in the seed banks of silt-amended peatland soils in low seed density, but were absent in the sand-amended peatland. The seed density of peatland species was highest in the surface 10 cm soil depth in the natural peatland, while it was highest in the 10–20 cm soil depth in the silt-amended peatland. Redundancy analysis identified that soil C:N, soil water content, and soil organic carbon explained most variance in seed bank composition. The result illustrates that soil amendment types affect soil, and change soil seed banks and revegetation potentials of peatlands. The silt-amended peatland had a higher revegetation potential than the sand-amended peatland. Removal of surface silt mineral soil is necessary to reduce the weed seeds and promote the recolonization of peatland species in the silt-amended peatland during restoration.