Can climate change stimulate organic matter decomposition in the volcanic ash soils under the two types of forest ecosystems?

気候変動は黒ぼく土の有機物動態を変えるのか?; 温度・水分変動に対する土壌微生物の有機物分解活性の応答

早川 智恵*; 小野 晴瑠*; 北村 里香*; 本間 咲子*; 彦坂 幸毅*; 後藤 晶子*; 目戸 綾乃*; 新井 宏受*; 小嵐 淳   ; 安藤 麻里子  ; 木庭 啓介*

Hayakawa, Chie*; Ono, Haru*; Kitamura, Rika*; Homma, Sakiko*; Hikosaka, Koki*; Goto, Akiko*; Medo, Ayano*; Arai, Hirotsugu*; Koarashi, Jun; Atarashi-Andoh, Mariko; Koba, Keisuke*

Andisols developed from volcanic ash accumulate a large amount of soil organic matter (SOM) due to high carbon storage capacity. However, Andisols can play both carbon sink and source, depending on environmental conditions and land management. Here, we investigated (1) the temperature and moisture sensitivities of the SOM decomposition rate by microorganisms and (2) the response of SOM decomposition enzyme activity of soil microorganisms to moisture fluctuations in Andisols from different forests (Nikko and Takayama). SOM decomposition rates were higher in Takayama soil than in Nikko soil. The SOM decomposition rates in Nikko soil tended to be more sensitive to moisture, while those in Takayama soil tended to be more sensitive to temperature. Analysis of metabolic functions of soil microorganisms indicated the microbial communities differ between the soils, suggesting the difference in the responses of SOM decomposition to changes in temperature and moisture is due to the difference in the microbial community.