Recent studies suggested that dense dwarf bamboo (e.g. Sasa senanensis) plays an important role in carbon cycling at temperate deciduous broad-leaved forest. However, it is unclear whether Sasa effects a “positive priming” to temperate forest soil carbon sequestration. In this study, we focused on determining the soil organic carbon (SOC) concentration and dissolved organic carbon (DOC) flux in surface mineral horizon (0-20 cm) at Takayama site with and without an understory of Sasa, to clarify the potential of “positive priming” of Sasa to soil carbon sequestration.

SOC concentration in 0-5 cm at TSY (with Sasa plot) was significantly 20% higher than TSN (without Sasa plot), but in 5-10, 10-15, and 15-20 cm were insignificant. Annual C input from litter layer to mineral soil as DOC at TSY was 10% higher than TSY due to a presence of Sasa litter fall. Water dissolvable organic carbon (WDOC) concentration in 0-5 cm with rootlitter in TSY was significantly 42% higher than TSN, but it was insignificantly different without rootlitter. In addition, DOC sorption rate in 0-5cm was almost the same (ca. 90%) at both plots. These results strongly suggest that Sasa effects a “positive priming” to forest soil carbon sequestration, particularly in surface mineral horizons, by increasing DOC sorption process which was produced from litter in above-ground and below-ground at Takayama site.