Flood Event Impact On Rice Production And Relation To Climate Change (Precipitation) Over Bangladesh

Bangladesh is the tiny south-Asian country which lies under the tropic of cancer and at the foot of the highest mountain range in the world, the Himalayas. It is low-lying flat country with big inland water bodies, including some of the biggest rivers in the world. Agriculture is the single largest producing sector of the economy and it contributes about 20.24% to the total Gross Domestic Product and 48.1% of total labour force. Rice is the staple dietary item and covers about 77.07% of the total cropped area(BBS, 2013). Rice alone shares about 96% of the total cereal food supply. On the other hand Bangladesh is the most vulnerable county for natural disaster like flood. The floods had a devastating effect on agricultural crops like rice. Due to change of climate(precipitation) and related extreme events, like rainfall, patterns change and also changes the flood that directly affected the rice production in Bangladesh and make the county food insecure. Ensuring food security for today is one of the major challenges, at the same breath, production and availability of food grains by optimum utilization of the limited water resource base in order to meeting the demand is also a great challenge for Bangladesh.This study is conducted on the base of secondary data and to find out the effect of rainfall that is directly related to the flood, 10 indices have been calculated using the software Rclim Dex1.0. Mann-Kendall test was performed to detect the trend and XLSTAT(2015) software was used to perform the Mann-Kendall test.This study investigated the long-term variations of rice production and tried reveals the relationship between rice cultivation and the hydrological environment. During the severe flood years, the influence of the severe floods on rice production is apparent. Normally Aman rice production is highly damaged but Boro crops increased yield after the severe flood years. These studies also investigate variations in rainfall pattern over the growing period and water requirement that effect on rice yield. Aus rice nursery preparation already felt there were not enough rainfall and decreasing trend the entire region except north. During Aman rice yield formation and ripening stage rainfall amount is less than requirement and all regions are the decreasing trend. In Boro season all regions and stages rainfall are decreasing trend except vegetative stage at month of January at the region of north, north-west, east and south east, the rate was not so high, that indicate the dependency of Boro rice cultivation will increase on the artificial irrigation. In this study another attempt took to investigate the vulnerable rice growing region, it was found that for Aus, Aman, and Boro drought vulnerable region was North west & north, North-west andSouth-west respectively and flood vulnerable region for Aus & aman was South-east region and for Boro was East.Average country rainfall was decreasing trend of recent 30 years. Even a thresh value 2500 mm rainfall was also decreasing trend. Rainfall extremes are Rx1 day, Rx5 day, R(44~88) mm and R(88+)mm is flood producing event. Rx1 was increasing trend in central and south region; But Rx5 day increased all regions except east. On the other hand for the case of R(44~88) mm increased in the south east and south west and R(88+) mm increased all region except east and north. Among 4 events, 4 were not increasing any region but 3 were increasing central south and south-east and south-west that is indicated that flood extreme event increasing in coastal region. On the other hand 4 events were decreasing in the east region that means the flood severity will decrease in the east region, among four 3 events were also decreasing in the region north. The north region was suffered by drought will increase in near future.The study is the first step in long-term trend analysis of climatic parameters after analysis historical data we showed that there is a wide range future change in rainfall extreme events over Bangladesh. As the rainfall is an important factor of Bangladesh, although there has few limitations, nonetheless the findings of this study can also be useful in general beneficial to a number of stakeholders of Bangladesh, particularly agricultural organization, disaster management and development and planning organizations...