Effects of soil properties in estimating soil respiration and methane absorption

Yamanuki, Hina*; Ichii, Kazuhito*; Yamamoto, Yuhei*; Teramoto, Munemasa*; Sun, L.*; Koarashi, Jun   ; Atarashi-Andoh, Mariko  ; Nagano, Hirohiko*; Hirano, Takashi*; Takagi, Kentaro*; Ishida, Sachinobu*; Takagi, Masahiro*; Kondo, Toshiaki*; Takahashi, Yoshiyuki*; Liang, N.*

Forest soils act as a CO source via emission through soil respiration and CH sink via absorption. However, due to insufficient observation and understanding, significant uncertainties remain in their spatio-temporal variations and their underlying mechanisms. In this study, we analyzed the effects of observed soil properties on explaining spatio-temporal variations in observed soil respiration and CH absorption. With the largest observation network across Asia developed and maintained by National Institute for Environmental Studies (NIES) and several observed soil properties such as C, organic matter properties, and mineral properties by Japan Atomic Energy Agency (JAEA), we estimated soil respiration and CH absorption across Japan based on random forest regression. Adding C data to the explanatory variables for CO estimation improved the accuracy of the estimation. The importance of mineral properties data as explanatory variables was greater than those of soil meteorological data such as temperature and soil moisture.