METHANE BUDGET FROM PADDY FIELDS IN INDIA

Abstract

Earlier measurements(1) of methane emission from rice paddy fields yielded a low methane budget of around 3 Tg/yr for India, and was reported at IPCC forums(2). This low budget was based on limited data. An extensive national methane measurement campaign from Indian paddy fields was launched in 1991, which involved a number of scientific institutions and universities with the National Physical Laboratory (NPL) at Delhi operating as a nodal agency. The results obtained during this campaign based on more than 2000 observations, covering the complete 1991 kharif(monsoon) season are reported here. The methane emission rates ranged between -0.20 and 66 mg m(-2) hr(-1). The irrigated fields (intermittently flooded) had the values between -0.20 and 3.6 mg m(-2) hr(-1) (seasonal integrated flux 0.05 to 2 g m(-2)), water logged (flooded) fields between 0.04 to 66 mg m(-2) hr(-1) (seasonal integrated flux 10-60 g m(-2)) and deep water regimes in the range between 1.10 and 23.3 mg m(-2) hr(-1) (seasonal integrated flux 14 to 24 g m(-2)). The methane budget from Indian paddies has been estimated to have an average value of 4.3 Tg yr(-1) and ranges between 2.7 and 6.4 Tg yr(-1).