Field Validation of the DNDC-Rice Model for Methane and Nitrous Oxide Emissions from Double-Cropping Paddy Rice under Different Irrigation Practices in Tamil Nadu, India

Abstract

Two-year field experiments were conducted at Tamil Nadu Rice Research Institute, Aduthurai, Tamil Nadu, India, to evaluate the effect of continuous flooding (CF) and alternate wetting and drying (AWD) irrigation strategies on rice grain yield and greenhouse gas emissions from double-cropping paddy rice. Field observation results showed that AWD irrigation was found to reduce the total seasonal methane (CH4) emission by 22.3% to 56.2% compared with CF while maintaining rice yield. By using the observed two-year field data, validation of the DNDC-Rice model was conducted for CF and AWD practices. The model overestimated rice grain yield by 24% and 29% in CF and AWD, respectively, averaged over the rice-growing seasons compared to observed values. The simulated seasonal CH4 emissions for CF were 6.4% lower and 4.2% higher than observed values and for AWD were 9.3% and 12.7% lower in the summer and monsoon season, respectively. The relative deviation of simulated seasonal nitrous oxide (N2O) emissions from observed emissions in CF were 27% and −35% and in AWD were 267% and 234% in the summer and monsoon season, respectively. Although the DNDC-Rice model reasonably estimated the total CH4 emission in CF and reproduced the mitigation effect of AWD treatment on CH4 emissions well, the model did not adequately predict the total N2O emission under water-saving irrigation. In terms of global warming potential (GWP), nevertheless there was a good agreement between the simulated and observed values for both CF and AWD irrigations due to smaller contributions of N2O to the GWP compared with that of CH4. This study showed that the DNDC-Rice model could be used for the estimation of CH4 emissions, the primary source of GWP from double-cropping paddy rice under different water management conditions in the tropical regions.

Greenhouse Gas Mitigation Potential of Alternate Wetting and Drying for Rice Production at National Scale—A Modeling Case Study for the Philippines

“…(2006), DNDC‐Rice by Oo et al. (2020), and DAYCENT by Begum et al. (2019), all reporting near zero or reduced simulated N 2 O emissions in paddy rice fields under flooded conditions.…”

Simulating the Long-Term Effects of Fertilizer and Water Management on Grain Yield and Methane Emissions of Paddy Rice in Thailand

“…The current study also found that AWD irrigation increased the simulated grain yields of SPR 1, but slightly decreased the simulated grain yields of PTT 1 and CNT 1 when compared with CF. Similarly, Tian et al [43] reported that MD and AWD can maintain or improve predicted rice yields when compared to CF. Oo et al [46] found that simulated grain yields in the CF (7846-8420 kg ha −1 ) and AWD (7852-9557 kg ha −1 ) treatments did not show a significant difference.…”

“…They found that, from 2051 to 2060, the single (SD) and multiple (MD) aeration decreased CH 4 emissions by 21.9 to 22.9% and 53.5 to 55.2% compared to continuous flooding (CF), respectively [36]. Moreover, Tian et al [43] found that when compared to CF, AWD reduced CH 4 emissions by 60-71% in Northeast China sites and 34-65% in South China sites. Hwang et al [58] used the DNDC model to estimate CH 4 emissions from rice paddy fields in South Korea under the Representative Concentration Pathway 8.5 (RCP-8.5) climate change scenario.…”

Kỹ thuật canh tác lúa tiết kiệm nước, giảm phát thải khí nhà kính và thích ứng biến đổi khí hậu

“…Hơn nữa, thực hành quản lý nước là một trong những yếu tố chính ảnh hưởng đến phát thải khí nhà kính trong ruộng lúa, đặc biệt là khí CH 4 (Oo et al, 2020). AWD làm giảm phát thải CH 4 bằng cách tăng các quá trình hiếu khí trong đất trồng lúa trong giai đoạn khô (Yang et al, 2020).…”