AsianScientist (Nov. 17, 2025) – The Sundarbans — the mangrove forest area between India and Bangladesh — are known for their climate vulnerability, frequent cyclones, and the loss of lives and livelihoods. The mangroves in the region feature prominently in public discussions because they serve as a natural shield against climate disasters such as extreme cyclones, protecting not just the Sundarbans but also human settlements away from the coast. Agriculture is the primary source of livelihood in the region. However, Sundarban’s soil is highly saline, which makes agriculture difficult. A new study has taken scientists one step closer to using salt-tolerant bacteria as naturally available fertilizers, which could help counter high salinity.
The paper, published in PLOS One, was authored by researchers at the Indian Statistical Institute, Kolkata. They studied the distribution of salt-tolerant bacteria in the Indian Sundarbans, which could help climate-proof the crops grown in the region and offer an alternative way of thinking about farming.
Earlier this year, some members of the same present research team discovered several new species of salt-tolerant bacteria that they claimed can be used as biological fertilizers, or “biofertilizers,” to sustain agriculture on highly saline soil. These bacteria are native to the Sundarbans.
“We are trying to develop biofertilizers,” said Pabitra Banik, professor at the Agricultural and Ecological Research Unit, Biological Science Division, Indian Statistical Institute, Kolkata, and corresponding author of the papers. The team is conducting trials of these biofertilizers with various agricultural research partners, including the Ramakrishna Mission at Narendrapur, near Kolkata.
However, biofertilizers cannot be used directly, even if the trials are successful. There is no one-size-fits-all — farmers need to account for how soil characteristics vary across the region. Each cropping season, along with standard fertilizers, changes the soil’s chemical and biological characteristics. So, farmers need to adjust which crops to cultivate and which cropping patterns to practice, and for that, they need an accurate map of soil characteristics, which is currently unavailable.
That is exactly what the research team did. They created remote sensing maps of 19 sites spread across five blocks in the Sundarbans. Each block, on average, covers four villages. These maps showed where salt-tolerant bacteria are more abundant, and whether cropping patterns affect this. The team found that blocks closer to the Bay of Bengal and some villages on the Sagar Islands had the highest levels of salt-tolerant bacteria. This knowledge will help them plan future biofertilizer production.
The researchers collected 80 soil samples from 19 sites in the Indian Sundarbans and conducted detailed laboratory analyses at the Indian Statistical Institute, Kolkata. Then, they measured various soil parameters and concluded that cropping patterns, such as monocropping and mixed cropping (e.g., rice with vegetables), did not significantly affect the soil’s salinity. “The only variation is due to the proximity of the sea,” said Banik. This finding will help farmers adjust their cropping accordingly and help researchers determine the most effective use of the biofertilizers.
He also suggested that ‘Krishi Vigyan Kendras’ should inform farmers about the exact salinity levels affecting crops and advise them on the most effective use of biofertilizers when they are finally available.
In the meantime, the research team is also developing effective ways to monitor rainfall, sea water levels, sea water temperatures, and acidity levels, among others, which will further boost these initiatives. “It will give us a complete picture of the Sundarbans,” said Banik.
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Source: Indian Statistical Institute, Kolkata ; Image: S.Narongrit99/shutterstock
The study can be found at: The spatial distribution of salt tolerant bacteria and other soil parameters under different agricultural systems of the Indian Sundarbans