Salinity has now become a major threat in Bangladesh, one of the world’s freshwater reservoirs. The problem of salinity in the southern part of the country is long standing. This problem has become more evident due to climate change. As a result, the health of millions of people in the region is at risk, land productivity is declining and many are losing their livelihoods. The total area of Bangladesh is about 2,48,677 sq km. Coastal areas cover about 20%. Coastal mortality is also higher than other parts of the country due to salinity, especially among children.
Due to salinity, food production is less than the requirement of 160 million people in the world every year. Not just salinity, but the problem of tiny plastic particles has been brought to the fore as a new threat to water around the world. At the same time, the issue of water pollution due to chemical fertilizers, pesticides and arsenic has come up. It has been said that these problems are poisoning the world’s freshwater sources.
The salinity levels of soil, groundwater and surface water in coastal Bangladesh have been increasing over the past few decades. Current salinity concentrations have already threatened crop production in coastal areas. The introduction of drip irrigation systems can go a long way in solving the problem of soil salinity. Farmers also need to be educated about the different salt tolerance levels of different crops so that they can choose the right crop for cultivation.
The development and adaptation of salt tolerant paddy and other crops and fish species seems to be a necessary step to address the salinity problem of coastal Bangladesh before sea level rises. According to a World Bank survey, 80 percent of the world’s drinking water, 81 percent of tap water and 93 percent of bottled water are contaminated by tiny plastic particles.
Figure 1: Causes of Salinity Intrusion in Coastal Belt of Bangladesh;
The same picture is seen in Bangladesh, the report said. 12 percent of people in Bangladesh still drink arsenic-contaminated water. On average, 3 percent of coastal children die of salinity. This rate is about 20 percent in the Barisal division.
The women of these areas collect fresh water from a distance of 20 km on average every day. This causes them various health problems. The human body needs a certain amount of salt and it comes from food and water. But the amount of salt in the water of coastal areas is many times higher. When this water enters the body, the health risk increases. It becomes even more dangerous, especially for pregnant women. Women who consume more saltwater during pregnancy experience convulsions and high blood pressure.
Due to this, the rate of child mortality in women is also higher, which has come up in the report of the World Bank. According to a study by the International Center for Diarrhea Research Bangladesh (ICDDRB), not only do coastal women suffer premature abortions due to salinity, but 3 percent of children also die.
In addition, high blood pressure is associated with high salt intake, which increases the risk of heart disease.
More than thirty percent of the country and net cultivable area. It extends up to 150 kilometers from the coast. Out of 2.6 million hectares of land in coastal and coastal areas, about 0.7 million hectares is cultivable land, which covers more than 30% of the total cultivable land of Bangladesh.
A part of the coastal region, the Sundarbans, is a reserve natural mangrove forest that covers about 4,500 km. The rest of the coastal region is used for agriculture. Cultivable areas in coastal districts are affected to varying degrees of soil salinity. Coastal and coastal areas of Bangladesh include tidal and river flood plains to the south, including the Bay of Bengal. Agricultural land use is very poor in these regions, with an average salinity of about 50% in the country creating unfavorable environment and hydroelectric conditions that limit the production of common crops.
According to experts, if people on the coast drink less salt water (such as rain
Figure 2: Increase in drinking water salinity in Bangladesh heightens risk of pregnancy complications; Source: Earth Journalism Network water), it is possible to lower their blood pressure.
In order to protect the people of the south from this health risk, it is necessary to provide fresh and sweet water. This can be done by digging large ponds and retaining rainwater. But the people of the area are so poor that it is not possible for them to dig ponds or hold rainwater for long.
Expansion of salt-affected areas as a cause of further infiltration of some areas and salt water, further restricting the production of common crops. Land use in this region is thought to be responsible for low use as well as crop intensity.
Salinity in the country received very little attention in the past. The increasing pressure of the growing population demands more food. So, it has become increasingly important to explore the possibilities of increasing the potential of this (saline) land to increase crop growth. It requires an assessment of the current state of land areas affected by salinity.
Therefore, it is necessary to make arrangements for digging ponds and retaining rain water on government initiative. As well as the measures to be taken:
1. Protective Dams: Land can be protected from saline water flow by installing dams of suitable size. The recommended size should be 1 m above the high tide level.
2. Provision of sluice gates in embankments: Sluice gates should be provided in the embankment system to remove excess water and prevent saline water from entering during high tide.
3. Ground leveling: A slight change in micro-relief increases the amount of salt in the raised spots.
The ground should be properly leveled to prevent waterlogging in low-lying containers, including shallow groundwater tables, and to facilitate uniform drainage of excess water.
4. Excess rain water conservation for irrigation: A portion of the excess water stored in the pond after meeting the requirements of kharif season can be used for rabi crops during the dry period.
5. Selection of Paddy Varieties: Although the coastal areas are relatively flat, there are differences in elevation in the regions where the standing water depth ranges from 1599 cm. Selection of rice varieties (BRRI rice 23, 30, 40 and 41), based on standing water and the amount of salinity in the field available in the country can largely overcome the situation.
6. Introduction of Crops in Winter Season: With the introduction of salt tolerant crops, crop density can be increased in about 0.596 million hectares of land by adopting proper soil and water management methods.
7. Covering the land in winter and summer months: Groundwater is present in saline and shallow depths (about 1.0 m). Excess soil moisture evaporates, which in turn increases salinity in the land.
Therefore, it is advisable to avoid land fall during Rabi season. Salt tolerant crops should be selected and grown. This will reduce salinity.
8. Crop Prohibition: Since common lands are fertile with low
Figure 3: Climate change-induced salinity affecting soil across coastal Bangladesh; Source: The Daily Star
organic matter content, suitable fertilizers need to be applied to increase crop yields. Potash fertilizer has an additional advantage under soil salinity.
9. Provision of sub-surface drainage: Salinity is very high in many parts of the coastal region. In order to grow crops successfully in those areas, salinity needs to be brought down with a pinch of salt. It is also necessary to lower the water table and maintain a deeper depth to prevent the effects of salt on the grown crop. To achieve the goal, a suitable sub-surface drainage should be placed to keep groundwater at least 1 m below the surface of the soil.
This technology is effective but somewhat expensive. Soil salinity is a global problem. Bangladesh is no exception.
In Bangladesh, salinity is one of the major natural hazards that disrupt crop production. The coastal region of Bangladesh is 20% of the country of which about 53% is affected by varying degrees of salinity. Agricultural land use is very poor in these areas. Concerns over food security issues in the country. The problem of salinity has received very little attention in the past. Nevertheless, the symptoms of such degradation of land with salinization are becoming more and more neglected in recent years. The increasing pressure of the growing population demands more food. In order to increase the growth of food crops, it has become necessary to explore the possibilities of increasing the potential of this (saline) land. Therefore, it is very important to tackle the problem of land salinization for food security in the country by adopting long term land management strategies.
Author is an Associate Editor at The Environment Review