Dhaka, Bangladesh (BBN)-Increasing levels of salinity, due to rising sea levels, is posing a challenge for rice scientists in Bangladesh.
Researchers say increasing levels of salinity could ruin several hectares of arable coastal land in the country, reports oryza.com.
Scientists have been trying to develop newer varieties of rice that can tolerate higher salinity, but salinity levels in the coastal districts of the country have surpassed levels that new rice varieties can sustain.
Seven new salinity tolerant rice varieties developed by the Bangladesh Rice Research Institute (BRRI) and the Bangladesh Institute of Nuclear Agriculture (BINA) - Brri Dhan 40, Brri Dhan 41, Brri Dhan 53, Brri Dhan 54, Brri Dhan 47, Brri Dhan 61 and Bina Dhan 8 - have failed to sustain high salinity levels in some of the coastal districts, according to local sources.
While BRRI and BINA developed rice varieties that can withstand salinity levels up to 8 deci Siemens per meter (dS/M), the salinity levels in nearly five coastal districts - Khulna, Patuakhali, Satkhira, Bagerhat and Barguna – are ranging between 8 dS/M and 16 dS/M, according to the Soil Resource Development Institute (SRDI).
However, the Director General of BRRI says paddy cannot be made tolerant to salinity levels beyond 12 dS/M.
SRDI classifies salinity into four levels based on the degree of salinity per meter.
According to a study by SRDI, salinity affected land in 19 coastal districts of Bangladesh and totals around one million hectares, up about 22 percent from about 833,000 hectares in 1973.
Currently, Bangladesh rice farmers use high-yielding non-salinity-tolerant hybrid varieties which can withstand up to 0.7 dS/M.
The new varieties developed by BRRI and BINA also proved to be low-yielding and highly irrigation dependent, say experts.
They noted that rice farmers are reluctant to experiment with newer varieties giving lower yields, despite them being salinity-tolerant varieties.
The BRRI said rice farmers could opt for other crops such as soybean, maize, barley and sugarcane to avoid salinity induced losses from rice production.
The USDA estimates Bangladesh’s rice production at 35.6 million tons in MY 2013-14 (July 2013 – June 2014), up about 5 percent from an estimated 33.8 million tons in MY 2012-13.
However, due to rising consumption needs, the country is still expected to import about 300,000 tons of rice in 2014, up from about 213,000 tons in 2013.
BBN/SS/AS-14May15-2:30pm (BST)