METHANE EMISSION FROM INUNDATED SALINE PADDY FIELDS OF WEST-BENGAL

In view of the paucity of information regarding methane emission from saline paddy soils, experiments were carried out both in pot-culture a nd in farmers' plots in saline and non-saline conditions. On natural s aline soil at Kakdwip, near Bay of Bengal, the average methane flux at two places during the entire period of growth of the salt tolerant ri ce cultivar MW-10 and salt-sensitive cv IR-36 was 1.19 g m(-2), far be low the mean value for inland areas of West Bengal. The salt sensitive cv IR-36 produced 5.6 g of methane per square metre over the entire g rowth period in a non-saline area near Kalyani; methane emission was i nhibited by 41-71% when grown with NaCl in pot-culture depending on th e degree of salinity. Microbial production of methane in the soil was inhibited by 50% with 0.18 mol l(-1) NaCl within 48 h. The reduced met hane emission from saline soil is partly due to inhibition of microbia l methane production in soil and partly due to decreased plant biomass with increasing salinity. Annual methane emission from saline tract p addy fields is estimated to be 0.013 Tg (1Tg = 10(12)g) for West Benga l and 0.083 Tg for India.