This study was initiated to identify the best agricultural management practices (BMPs) with low Greenhouse GAS (GHG) emissions supporting climate change mitigation in salt affected paddy soils, as it would eventually help sustain the rice production in such areas of Sri Lanka.

The research was carried out in Madampe, Puttalam District and Umaneri, Mannar in Maha season (during north-east monsoon from September to March). The newly improved salinity tolerant variety BG 310 was planted in the salinity affected (i.e. Electrical conductivity of saturation extract (EC- Sat) in the range 2-4 dS/m) paddy fields to study the variations in GHG emissions under different combinations of the following management options; a) maintaining a 2-3 cm water level until milking, b) organic matter addition, c) broadcasting seeds and d) transplanting of rice seedlings. The above options were considered variably in 4-plots within each field along with a control. The closed chamber method was used to collect three replicates of gas samples from each plot. Collected gas samples were analyzed using gas chromatography. CH4, N2O and CO2 emissions were measured starting from the date of seeding (broadcasting or transplanting) onwards at weekly intervals. The weekly CH4 and CO2 fluxes ranged from 0.27 to 0.628 mg m-2 hr-1 and -115.05 to 549.78 mg m-2 hr-1, respectively in both sites. Emission of N2O was negligible. Organic matter addition seemed to reduce denitrification, though intermittent water supply (with dry and wet periods) seemed to induce it; but the N2O emissions were still too low. The lowest GHG emissions were observed when intermittent irrigation water supply, addition of organic matter, and transplanting method were applied as the combination of BMPs.