Simulations of Nitrogen Emission in Paddy Fields Under RCP 8.5 Scenario in Korea.

Under climate change, it is likely that rice yield would decrease due to elevated temperature conditions in Korea. For climate change adaptation, more fertilizer application could be recommended, which would result in increased loss of nitrogen in paddy fields. The objectives of this study was to simulate the potential loss of nitrogen in rice paddy fields under RCP 8.5 scenarios in Korea. Crop growth was simulated at 53 sites using weather data derived from RCP 8.5 scenario provided by the Korea Meteorological Administration (KMA). Under the assumption that soil characteristics in a paddy field would be similar to each other, representative soil input data were prepared using soil analysis data obtained from one of study site where long term crop yield has been recorded. In simulation, fertilizer was applied at the time of transplanting, tillering, and ear formation. In total, 110 kg/ha were applied in the simulation. Three cultivars including Hwasung, Chucheong, and Odae were used. Total Nitrate concentration and Mineralization rate in the soil tended to decrease under future climate conditions for all cultivars. In contrast, the rate of denitrification and volatilization differed by cultivars. For example, the amount of denitrification for Hwasung was about 6.5 times greater (3.39 kg/ha) than that of other cultivars (0.49 kg/ha and 0.52 kg/ha for Chucheng and Oade). Volatilization rate was greater in the order of Hwasung (97%), Chucheong (72%), and Odae (68%). These results indicated that varietal difference would exist for loss of nitrogen by soil temperature, soil water, and the amount of fertilizer, which merits further field studies to quantify nitrogen loss during crop growth by variety.