Identification of greenhouse gas hot-spots and predicting district-wise GHG Intensities in rice based crop rotations in India using DNDC model

Monday, 15 December 2014
Jagadeesh Babu Yeluripati, James Hutton Institute, Aberdeen, AB15, United Kingdom, Steve E Frolking, Univ New Hampshire, Durham, NH, United States, Changsheng Li, University of New Hampshire, Durham, NH, United States, Dali Rani Nayak, University of Aberdeen, School of Biological Sciences, Aberdeen, United Kingdom and Tapan Kumar Adhya, KIIT university, School of Biotechnology, Bhubaneswar, India
Indian scientific research on rice cultivation has been targeted primarily at enhancing crop productivity for the wide range of soil and climate conditions across India. With the understanding that rice paddies are major source of atmospheric CH4 and N2O, there is a need for careful evaluation of the source strength of this ecosystem, and the influence of soil, water and crop management practices on both CH4 and N2O fluxes. A major challenge in meeting this objective lies in reducing the large uncertainties associated with regional and global level estimates of GHG emissions. Process-based biogeochemical models like DNDC (Denitrification and Decomposition model) can provide important insights into how agricultural management of rice paddies influences water resources, yields and greenhouse gas emissions. To quantify the CH4 and N2­O emissions from rice based crop rotations of India, DNDC model was modified, calibrated and evaluated at different sites across India. The observed N uptake, yields, CH4 and N2O emissions were in agreement with the values predicted by the model. To drive the model across India, a unique database was prepared combining soil/climate/landuse and management information. By linking the spatial database to DNDC, CH4 and N2O emissions from Indian rice based crop rotations for the rice growing season in the year 2000 were simulated on day-by-day basis. CH4 and N2O emissions from rice paddies in India from rice based-growing season were estimated to be 3.8 and 0.1 - 0.08 Tg (1 Tg = 1012 gm). Of the total CH4 emissions 30.6% (1.2 Tg) is emitted from single irrigated rice. 30.0% (1.1 Tg) and 14.46%(0.56 Tg) of total CH4 is emitted from double rice and single rainfed rice cropping system. 32.9% (33.16 Gg) of the total N2O emissions is emitted by upland rice followed by Single rainfed rice cropping system which emits about 19.9%(20.06 Gg) of total N2O . This paper presents a framework on GIS databases and a process-based biogeochemical model for estimation of greenhouse gas emissions from Indian based crop rotations.