Rice Yield, Submergence and Climate Change : Evidence from Coastal Barisal, Bangladesh
In this paper, the effects of submergence due to heavy rainfall and river over flow on rice production in the coastal Barisal region of Bangladesh are investigated. Plot level data is used to compare rice yields of cultivars in high and low submergence prone areas and analyse variation in yield when high-yielding varieties (HYVs) versus local seeds are used. Results suggest that rice yields are on average some ten per cent lower in 'high submergence areas' relative to 'low submergence areas'. Both depth of submergence and duration have a negative effect on yield, with local varieties of rice seemingly better adapted to submergence. The widely down Aman variety of rice faced an average of nine days of submergence in 2010, with 31 per cent plots under 1-3 meters of water for 3-7 days. Aman yield is regressed on a number of variables including submergence factors and it is found that depth has significant negative effect than duration of submergence on Aman production. The findings suggest that an additional 13,564 hectares of Aman area in Barisal is likely to be inundated tor 3-7 days in 2050 due to sea level rise and increased storm surge events. Correspondingly, given current levels of technology, it can be predicted that a production loss of 10,856 tons of Aman will take place in the future. The study recommends the introduction of submergence tolerant rice cultivars, integrated farming of rice crop, vegetable, fish and poultry; vegetable gardening on floating bed; duck rearing in submerged area and low-cost water control technology as adaptation options against climate change.