Rising salinity is reducing crop yields, degrading soil fertility, and making shrimp farming increasingly uncertain in coastal Khulna, threatening farmers’ livelihoods.
Sayed Morol, a farmer from Mahmudkathi in Paikgachha upazila, cultivates rice on one bigha of land. He spends Tk8,000–10,000 per season to produce around 16 maunds of rice, selling each maund for Tk1,000. Previously, the same plot yielded 18–20 maunds.
He said salinity had increased over the past decade after an embankment along the Kopotaksho River collapsed in 2015, allowing saline water to inundate the area.
Abdul Kader Morol, who owns a banana plantation, said his land once supported a variety of crops. However, rising salinity has stunted banana plants and prevented the fruits from developing properly.
Agriculture and fisheries in Khulna’s Dakop, Koyra, Paikgachha and Batiaghata upazilas are facing growing pressure from climate change, reduced upstream freshwater flows, erratic rainfall and cyclone-induced storm surges.
An analysis of soil and river water data from Khulna, Bagerhat and Satkhira between 2004 and 2022 found that salinity generally increases during the dry season and declines during the monsoon as rainfall and freshwater flows dilute salt concentrations. Embankment breaches during cyclones can further worsen the situation by allowing saline water to inundate farmland.
Although rice can be cultivated during the monsoon, freshwater shortages in winter and summer leave many fields uncultivated, limiting opportunities for a second crop and reducing farmers’ annual incomes.
Md Yunus Gazi, a farmer from Noakathi in Paikgachha, operates a 13-bigha shrimp enclosure, locally known as a gher, including eight bighas of his own land beside the Hariya River. The land remains submerged in saline water for seven to eight months a year, making conventional crop cultivation difficult.
Gazi said farmers had relied on black tiger shrimp farming for around three decades because persistent salinity had left them with few alternatives.
Shrimp farming costs Tk20,000–30,000 per bigha and generates around Tk30,000 in returns, leaving farmers with little profit. Excessive salinity can also cause shrimp stocks to die, increasing financial risks.
During the dry season, he attempts to cultivate Boro rice by draining saline water and bringing in freshwater. Managing water conditions costs an additional Tk10,000–12,000 per bigha, while yields reach around 25–30 maunds.
Thirty years ago, the same land supported two rice harvests at lower costs and with higher yields. Rising salinity and declining soil fertility have since made cultivation more expensive and less productive.
Gazi alleged that pressure from politically influential individuals and their associates often leads to sluice gates being opened, allowing saline water to enter farmland. Even farmers who keep saline water out of their fields cannot fully protect their land, as salt spreads from neighboring plots, he said.
Farmer Mizanur Rahman said rising salinity had made crop cultivation increasingly difficult while also affecting shrimp production.
“We want to grow rice and vegetables; we want a green environment filled with trees and plants—but salinity makes this impossible. Consequently, we are forced to convert our land into shrimp enclosures,” he said.
Kamrul Islam, a farmer from Noakathi who owns two bighas of land near the Hariya and Gonkhali rivers, said his land once supported a variety of crops. He now uses it for shrimp farming, but attempts to cultivate rice with freshwater during the dry season often prove unprofitable because of the additional costs.
Excessive salt accumulation also makes it harder for plant roots to absorb water, affecting seed germination, plant growth, and nutrient uptake. Low organic matter and imbalanced soil nutrients further reduce productivity. Research in the southwestern coastal region has highlighted low levels of organic matter and total nitrogen in some areas, alongside concerns about irrigation water quality.
Shrimp farming, once a major source of income in coastal Khulna, is also facing growing uncertainty. Higher salinity does not necessarily translate into higher production, as shrimp cultivation depends on suitable water quality, temperature, dissolved oxygen levels, and disease management. Fluctuating salinity, excessive temperatures, and pollution can reduce shrimp growth and survival.
Farmers must contend with both unsuitable and excessively high salinity, while limited access to modern water-quality monitoring leaves them vulnerable to sudden changes.
Nazrul Islam, deputy director of the Department of Agricultural Extension in Khulna, said waterlogging and salinity had severely affected agriculture in the region. The district’s coastal location and climatic conditions have made changes in land characteristics a major challenge.
Excessive sodium content damages the physical and chemical structure of soil, preventing plants from absorbing essential nutrients and water. High soil salinity also reduces seed germination and hampers seedling growth. As a result, yields of several rice varieties have declined, while cultivation of some varieties has been discontinued.
The intrusion of saline water and increasing salinity in water sources have also led to the conversion of large areas of paddy fields into saline-water shrimp farms. During the dry season, particularly from March to May, salinity in rivers, canals, and groundwater reaches extreme levels.
Excessive salinity also reduces the activity of beneficial soil microorganisms and earthworms, undermining natural soil fertility.
