SOIL AND WATER SALINITY, THEIR MANAGEMENT IN RELATION TO CLIMATE CHANGES IN COASTAL AREAS OF BANGLADESH

Abstract

Climate change due to global warming and its negative consequence on environment and agro ecosystem is a serious concern of global community of current age. To assess the present soil and water salinity status in coastal areas a soil survey work following standard methods has been completed by Soil Resource Development Institute (SRDI) in 2009. It was observed that out of 2.86 million hectares of coastal and offshore lands about 1.056 million ha of arable lands are affected by varying degrees of salinity. A comparative study of the salt affected area between  1973  to 2009 showed that about 0.223 million ha (26.7%) new land was affected by various degree of salinity during last four  decades . It was also observed that about 0.035 million hectares of land (3.5%)  new land was affected by various degrees of salinity during last 9 years only (2000-2009). High amount of S and high pH may be the possible causes for P deficiency in coastal areas. Coastal soils are rich in micronutrient elements except Zn. In shrimp cultivated areas flooding with high saline water for a considerable time in each year causing higher soil salinity in all the horizons. A long term soil and water salinity monitoring data of SRDI shows that soil and water salinity between 1991 and 2008  has increased at least   2-10 times. Several common and location specific agricultural constraints have been identified in the field through field investigation/observation and farmer’s interview. Proper fertilizer management practices need to be addressed in coastal saline areas.