Fog and cold put boro seedbeds at risk of cold injury in Sharsha, Jashore

In the first week of January 2025, cold and fog both deepened in Sharsha upazila and the Benapole area on the border of Jashore district. Fields lay under thick fog from evening until the next morning. Jagonews24 reported on 6 January that farmers' newly prepared boro rice seedbeds were at risk of cold injury, and that farmers were covering them with polythene to save the seedlings.

Sharsha is a border upazila of Jashore, with India's West Bengal to the west. It contains the town of Benapole, site of Bangladesh's largest land port.

Citing the weather office, the report said winter had arrived late in the region that season. Warm weather lingered until late November; temperatures began falling from the start of December, and by early January the cold had set in.

On Sunday, 5 January, an official at the weather office run by the Bir Shrestha Shahid Matiur Rahman air base in Jashore told Jagonews24 that temperatures in Jashore had been falling for a week, by one to two degrees a day.

Citing the upazila agriculture extension office, the report said boro seedbeds had been prepared on 1,175 hectares in Sharsha that season, and that many farmers were still preparing more.

Farmer Zahidul Islam told Jagonews24 that it was the peak season for boro seedbeds, but dense fog and severe cold at the very start threatened to destroy them, so farmers were buying polythene at the market to protect them. Another farmer, Abdul Mannan, said they had already made a loss that year because of a poor aman harvest; buying polythene at high prices was adding to their costs, and he feared boro farming would become expensive if the weather continued.

Sharsha upazila agriculture officer Dipak Kumar Saha told Jagonews24 that seedbeds are damaged by the cold and by water collecting on the tips of seedlings in cold, foggy weather, so farmers had been advised to cover entire seedbeds with polythene. He said many farmers had raised seedlings using the synchronised (somoloy) method that year.

Md Abu Talha, deputy director (training) at the Department of Agricultural Extension in Jashore, said there is no substitute for quality seedlings for a good boro yield. Drawing on experience, farmers were covering seedbeds with polythene at night and removing it in the day. He said that if temperatures fell further, farmers were also being advised to drain the cold water from seedbeds and irrigate more often.

Published guidance from the agronomy division of the Bangladesh Rice Research Institute (BRRI) runs along the same lines:

• During a cold wave, cover seedbeds with transparent polythene from 10 am until evening.
• If the cold wave lasts a long time, keep the seedlings covered with polythene day and night.
• In that case, leave the polythene partly open on both sides of the seedbed.

During the January 2024 cold spell, agriculturists quoted by New Age likewise advised keeping seedbeds covered with transparent polythene at night, irrigating them with groundwater every morning and clearing the dew from seedbeds and seedlings every day. Farmers should consult their upazila agriculture officer before applying any fungicide or fertiliser to damaged seedbeds.

Boro is Bangladesh's main rice season; New Age reported in January 2024 that it accounts for about 55 per cent of the country's rice production. Seedlings grow on seedbeds for about 45 days before they are planted out, and transplanting usually begins in mid-January and ends by mid-February. Moshiur Rahman, who teaches agronomy at Bangladesh Agricultural University, told New Age then that boro suffers stunting below 15 degrees Celsius, and that dense fog hinders photosynthesis by hiding the sun.

In the synchronised (somoloy) method that Dipak Kumar Saha mentioned, rice seed is sown by machine in plastic trays and the seedlings are planted with a rice transplanter at an even depth. According to a 2023 report in The Daily Star Bangla, farmers in a field plant the same variety at the same time, so the crop ripens together and can be harvested together.

Photo: Abuxyz bokor / Wikimedia Commons (CC BY-SA 4.0)

Sources: Jagonews24, Bangladesh Rice Research Institute (BRRI), New Age, The Daily Star Bangla, Wikipedia