[M-IS14] Biogeochemistry

[MIS14-04] Effect of the landslide occurrence on the soil carbon/nitrogen loss in the Southern Japanese Alps.

*Catur Putra Satgada¹, Fumitoshi Imaizumi¹, Tomohiro Egusa¹ (1.Shizuoka University)

Keywords:Soil carbon and nitrogen loss, landslides, forest ecosystem

Forest ecosystems are one of the world’s largest carbon sinks, storing enormous amounts of carbon and also nitrogen both above and below ground. Landslides are the major disturbances for forest ecosystems in mountainous areas, particularly in Japan. The objective of this study was to quantify the carbon and nitrogen loss from forest soil due to historical landslide events. We targeted the Ikawa University Forest, Southern Japanese Alps, and estimated the soil mass moved with landslides from 1948 to 2012 using aerial photographs and LiDAR DEM. Then, we obtained soil physical properties, and total carbon and nitrogen in the surface soil (< 55 cm). Finally, we calculated the carbon and nitrogen loss due to the landslide events. The results showed that the organic carbon and total nitrogen contents in shallow soil layers were higher than those in deeper soil layers. The amount of gravel in the forest floor has a geological impact on soil density, soil organic carbon, and total nitrogen. Furthermore, landslides in the Ikawa University Forest resulted in the loss of 481.4 kg.m^-2 of soil between 1948 and 2012. Over 64 years, this resulted in soil carbon and nitrogen losses, significantly.