The effect of warming and drought on fine root decomposition (FRD) was examined using a litterbag method. The study site contained 12 plots (2 temperature levels × 2 precipitation levels × 3 replicates). The warming treatment consisted of warmed plots (TW; +3.0℃) with infrared-heaters and temperature control plots (TC). Drought system consisted of decreased precipitation plots (PD; -30%) using transparent panel and precipitation control plots (PC). Litter bags containing fine root litter of 2-year-old Pinus koraiensis were retrieved after 3, 6, and 12 months. After 12 months, FRD rate significantly increased by only warming (TW*PC=35.9%, TW*PD=35.5%, TC*PC=31.1% and TC*PD=29.2%), while there were no significant differences across treatments until 6 months. This warming effect is supported by the positive relationship between soil temperature and FRD rate (p<0.001; r2=6835). However, drought had no effect on FRD rate during the study period. C/N ratio in TW was significantly lower than that in TC both after 6 months (TW=34.6% and TC=40.5%) and 12 months (TW=31.5% and TC=38.2%). It seemed that litter quality (C/N ratio) was first changed by warming, and it led to the changes of FRD.
This study was supported by Korea Ministry of Environment (2014001810002).