Spatial variation in soil respiration rate is controlled by the content of particulate organic materials in the volcanic ash soil under a plantation

Abe, Yukiko*; Liang, N.*; Teramoto, Munemasa*; Koarashi, Jun   ; Atarashi-Andoh, Mariko  ; Hashimoto, Shoji*; Tange, Takeshi*

This study aimed to clarify the causes of spatial variation in soil respiration rate on volcanic ash soil. From January 2013 to August 2019, soil respiration rates were measured at 40 measuring points periodically at a 35-year-old plantation in Tokyo, Japan. In August 2019, the carbon content of the litter layer, total carbon content of soil organic matter (SOM), carbon content of the low-density fraction (LF-C) of SOM, fine root biomass, and bulk density of soil were measured at all measuring points. Results of the multiple regression analysis showed that the model with only the LF-C as an explanatory variable had the highest capability for predicting the respiration rate at a soil temperature of 20C, indicating that LF-C, which is considered to be readily available to soil microorganisms, can be the main factor responsible for the spatial variation in soil respiration rate.