Premium
Increased night temperature reduces the stimulatory effect of elevated carbon dioxide concentration on methane emission from rice paddy soil
Author(s) -
CHENG WEIGUO,
SAKAI HIDEMITSU,
HARTLEY ANNE,
YAGI KAZUYUKI,
HASEGAWA TOSHIHIRO
Publication year - 2008
Publication title -
global change biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.146
H-Index - 255
eISSN - 1365-2486
pISSN - 1354-1013
DOI - 10.1111/j.1365-2486.2007.01532.x
Subject(s) - carbon dioxide , zoology , methane , paddy field , chemistry , horticulture , agronomy , biology , organic chemistry
To determine how elevated night temperature interacts with carbon dioxide concentration ([CO 2 ]) to affect methane (CH 4 ) emission from rice paddy soil, we conducted a pot experiment using four controlled‐environment chambers and imposed a combination of two [CO 2 ] levels (ambient: 380 ppm; elevated: 680 ppm) and two night temperatures (22 and 32 °C). The day temperature was maintained at 32 °C. Rice (cv. IR72) plants were grown outside until the early‐reproductive growth stage and then transferred to the chambers. After onset of the treatment, day and night CH 4 fluxes were measured every week. The CH 4 fluxes changed significantly with the growth stage, with the largest fluxes occurring around the heading stage in all treatments. The total CH 4 emission during the treatment period was significantly increased by both elevated [CO 2 ] ( P =0.03) and elevated night temperature ( P <0.01). Elevated [CO 2 ] increased CH 4 emission by 3.5% and 32.2% under high and low night temperature conditions, respectively. Elevated [CO 2 ] increased the net dry weight of rice plants by 12.7% and 38.4% under high and low night temperature conditions, respectively. These results imply that increasing night temperature reduces the stimulatory effect of elevated [CO 2 ] on both CH 4 emission and rice growth. The CH 4 emission during the day was larger than at night even under the high‐night‐temperature treatment (i.e. a constant temperature all day). This difference became larger after the heading stage. We observed significant correlations between the night respiration and daily CH 4 flux ( P <0.01). These results suggest that net plant photosynthesis contributes greatly to CH 4 emission and that increasing night temperature reduces the stimulatory effect of elevated [CO 2 ] on CH 4 emission from rice paddy soil.