Estimation of nitrous oxide emissions from rice paddy fields using the DNDC model: a case study of South Korea

The Denitrification-Decomposition (DNDC)-Rice is a mechanistic model which is widely used for the simulation and estimation of greenhouse gas emissions [nitrous oxide (N₂O)] from soils under rice cultivation. N₂O emissions from paddy fields in South Korea are of high importance for their cumulative effect on climate. The objective of this study was to estimate the N₂O emissions and biogeochemical factors involved in N₂O emissions such as ammonium (NH₄⁺) and nitrate (NO₃^-) using the DNDC model in the rice-growing regions of South Korea. N₂O emission was observed at every application of fertilizer and during end-season drainage at different rice-growing regions in South Korea. Maximum NH₄⁺ and NO₃^- were observed at 0-10 cm depth of soil. NH₄⁺ increased at each fertilizer application and no change in NO₃^- was observed during flooding. NH₄⁺ decreased and NO₃^- increased simultaneously at end-season drainage. Minimum and maximum cumulative N₂O emissions were observed at Chungcheongbuk-do and Jeju-do regions of South Korea, respectively. The simulated average cumulative N₂O emission in rice paddies of South Korea was 1.37 kg N₂O-N ha^-1 season^-1. This study will help in calculating the total nitrogen emissions from agriculture land of South Korea and the World.