Elevated Temperature Treatment Induced Rice Growth and Changes of Carbon Content in Paddy Water and Soil
2018
Hong, S.C., National Institute of Agricultural Sciences, Rural Development Administration, Wanju, Republic of Korea | Hur, S.O., National Institute of Agricultural Sciences, Rural Development Administration, Wanju, Republic of Korea | Choi, S.K., National Institute of Agricultural Sciences, Rural Development Administration, Wanju, Republic of Korea | Choi, D.H., National Institute of Agricultural Sciences, Rural Development Administration, Wanju, Republic of Korea | Jang, E.S., National Institute of Agricultural Sciences, Rural Development Administration, Wanju, Republic of Korea
BACKGROUND: The global mean surface temperature change for the period of 2016~2035 relative to 1986~2005 is similar for the four representative concentration pathway (RCP)'s and will likely be in the range of 0.3℃ to 0.7℃. Climate change inducing higher temperature could affect not only crop growth and yield, but also dynamics of carbon in paddy field. METHODS AND RESULTS: This study was conducted to evaluate the effect of elevated temperature on the carbon dynamics in paddy soil and rice growth. In order to control the elevated temperatures, the experiments were set up as the small scale rectangular open top chambers (OTCs) of 1 m (width)×1 m (depth)×1 m (height) (Type 1), 1 m (W)×1 m (D)×1.2 m (H) (Type 2), and 1 m (W)×1 m (D)×1.4 m (H) (Type 3). The average temperatures of Type 1, Type 2, and Type 3 from July 15 to October 30 were higher than the ambient temperatures at 0.4℃, 0.5℃, and 0.9℃, respectively. For the experiment, Wagner's pots (1/2,000 area) were placed inside chambers. The pots were filled with loamy soil, and chemical fertilizer and organic compost were applied as recommended after soil test. The pots were flooded with agricultural water and rice (Shindongjin-byeo) was planted. It was observed that TOC (total organic carbon) of the water increased by the elevated temperatures and the trend continued until the late growth stage of the rice. Soil TOC contents were reduced by the elevated temperatures. C/N ratios of the rice plant decreased by the elevated temperature treatments. Thus, it was assumed that the elevated temperatures induced to decompose soil organic matter. Elevated temperatures significantly increased the culm length (P less than 0.01) and culm weight (P less than 0.05) of rice, but the number and weight of rice panicle did not showed significant differences.
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