A state-wise assessment of methane budget for Indian paddy fields for the year 1994 has found four 'hot spot' states in India — West Bengal, Bihar, Madhya Pradesh and Uttar Pradesh — that account for 53.9% of total methane emission 1 . The total methane budget for the year was found to be in the range of 4.09 ± 1.19 terragram per year1.
The rain-fed flood prone paddy water regimes were found to be the major contributor to these emissions. The national trend, calculated from 1979-2006 estimates was in the range of 3.62 ± 1 to 4.09 ± 1.19 terragram per year.
Methane emissions were found to be enhanced by parameters such as soil organic carbon (1.5 times), paddy cultivars (1.5 times), age of seedlings (1.4 times), and seasons (1.8 times in Kharif i.e. monsoon than in Rabi i.e winter season).
This study pointed out key gap areas in activity data for for irrigated intermittently flooded single aeration as well as multiple aeration paddy water regimes and for different parameters such as organic amendments and soil organic carbon.
It reiterated the need for an appropriate survey to further refine methane emission estimates from rice paddy fields in India.
The authors of this work are from: National Physical Laboratory, New Delhi, India; Regional Research Laboratory, Bhubaneswar, Orissa, India; Institute of Radio-Physics and Electronics, Kolkata University, West Bengal, India; Central Rice Research Institute, Cuttack, Orissa, India; International Rice Research Institute-India Office, NASC Complex, New Delhi, India; Institute of Ocean Management, Anna University, Chennai, Tamil Nadu, India; Tezpur University, Tezpur, Assam, India; National Remote Sensing Agency, Hyderabad, Andra Pradesh, India; Central Fuel Research Institute, Dhanbad, Jharkhand, India; Regional Research Laboratory, Trivandram, Kerala, India.