Salinity has caused significant negative effects on agricultural production. This research is focused on the vulnerabilities of soil and water salinities on crop, fish, and livestock production across the Kalapara coastal belt of Bangladesh. Several parameters were measured as indicators of salinity. The electrical conductivity of water was found to be significant with TDS, F−, Cl−,
Salinity intrusion is one of the major environmental issues throughout the world [
The Kalapara coastal belt is one of the nearest areas to the Bay of Bengal in Bangladesh. This bay is one of the greatest sources of saline water. The electrical conductivity is an indicator of this saline water [
Agricultural production has contributed 21% of the national GDP of Bangladesh [
Surface water and groundwater are both connected to major rivers along the coastal belt through various estuaries and water inlets [
Due to increased salinity there is a shortage of grazing land and fodder crops for livestock production. Because of this, communities must utilize other natural resources to make up for the lack of protein from livestock. This shortage of milk and cattle in the coastal areas is also documented in other studies [
In addition, saline water has been increasing across the coastal belt due to the intensity of cyclones in Bangladesh. This saline water has many connections with fresh water bodies across the coastal belt. It leads to changes in the trophic structure and diversity of shallow fresh water bodies such as increased strength of trophic interactions. As a result, saline water fish are mixed with fresh water species. Because of this, the intrusion of saline water in different fresh water bodies has played a significant role in the disappearance of some fish species [
There are not currently any established guidelines for salinity levels in agricultural production systems in Bangladesh [
Kalapara Upazila is the most salinity prone area in the southwestern part of Bangladesh. It is adjacent to the Amtali Upazila of Barguna district on the north, the Bay of Bengal on the south, and Rabnabad channel and Galachipa Upazila on the east. The total area of Kalapara Upazila is 491 square kilometers and the population is 238,000 [
Geographical position for water and soil sampling study areas across the coastal belt.
Samples | Locations | Latitude | Longitude |
---|---|---|---|
Water | Ander manik river | 21°53.67933′ | 90°8.36508′ |
Shibbaria river | 21°51.26377′ | 90°7.52335′ | |
Badurtoli Canal | 21°54.66933′ | 90°8.36548′ | |
Char Gangamoti (beach area) | 21°48.24381′ | 90°12.23918′ | |
Kuakata beach (left) | 21°48.81624′ | 90°7.30991′ | |
Kuakata beach (right) | 21°48.81645′ | 90°7.30976′ | |
Char Gangamoti Mangrove | 21°49.24878′ | 90°12.7492′ | |
Sonatula River | 21°53.67948′ | 90°8.36345′ | |
ShantiBagh Canal | 21°53.3578′ | 90°8.4617′ | |
Paira river | 22°27.79685′ | 90°20.47599′ | |
Kalapara town pond | 21°53.3569′ | 90°8.8653′ | |
Kalapara town tube well water | 21°53.4689′ | 90°8.8952′ | |
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Soil | Mustafapur Nilgonj | 21°56.07547′ | 90°9.912′ |
Char Gangamoti (beach area) | 21°48.43599′ | 90°12.3969′ | |
Kuakata beach (left) | 21°48.81624′ | 90°7.30991′ | |
Kuakata beach (right) | 21°48.81645′ | 90°7.30976′ | |
Char Gangamoti Mangrove | 21°49.24878′ | 90°12.7492′ | |
Niamatpur | 21°57.92477′ | 90°11.97595′ |
Study area on a Bangladesh map.
Sampling locations in the study area.
An inception meeting was arranged at the Department of Agricultural Extension (DAE) in the Kalapara Upazila area of the coastal belt for 3 days. This meeting was conducted with government officials, fishermen, visitors, and farmers who have been living in the Kalapara Upazila area. This meeting was conducted to discuss the soil and water salinities and their possible effects on crops, fish, and livestock. During this meeting, participants contributed their unique perspectives regarding soil and water salinity and the possible impacts upon crops, livestock, and fish. Based on this meeting, we were able to identify the major areas affected by salinity at Kalapara coastal belt for the collection of soil and water samples.
Water samples were collected randomly with different salinities along the coastal belt at Kalapara Upazila for analysis of salinity indicators in 2016. Distance of each collected water sample for a location was 50 meters; three collected water samples were mixed together for making a sample for each location. Samples were collected in 100–500 ml polyethylene plastic bottles. Each bottle was cleaned thoroughly by rinsing with diluted HCl followed by washing with distilled water [
Soil samples were collected from different areas affected by salinity on the coastal belt at Kalapara Upazila for the analysis of chemical properties. Soil samples were collected by Auger from different locations randomly. Distance of each collected soil sample was about 15 meters for a location; four collected soil samples were mixed together for making a sample for each location. All collected samples were kept in polyethylene zip lock bags through proper marking. Then samples were carried into the Laboratory of Environmental Science at Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU) and Bangladesh Council of Scientific and Industrial Research (BCSIR) in Dhaka for analysis of chemical properties. All soil samples were preserved at room temperature in the laboratory before the analysis of the chemical parameters was completed.
Water pH was determined with a glass electrode pH meter (Model: Metrohm 906 Titrande) [
Anions like fluoride (F−), chloride (Cl−), nitrite (
Methods for the determination of salinity indicators in soil and water samples across the Kalapara coastal belt in Bangladesh.
Samples | Chemical properties | Methods/instrument for chemical analysis |
---|---|---|
Water | Salinity % | Salinity meter (Model: HACH SensION 156) |
Conductivity ( |
Conductivity meter (Model: HANNA HI-8633) | |
TDS, mg/l | TDS meter (Model: HACH SensION 156) | |
pH | Glass electrode pH meter (Model: Metrohm 906 Titrande) | |
Fluoride (F-), mg/l | Ion chromatography (Model: Dionex ICS-1600) | |
Chloride (Cl-), mg/l | Ion chromatography (Model: Dionex ICS-1600) | |
Nitrite ( |
Ion chromatography (Model: Dionex ICS-1600) | |
Bromide (Br-), mg/l | Ion chromatography (Model: Dionex ICS-1600) | |
Nitrate ( |
Ion chromatography (Model: Dionex ICS-1600) | |
Phosphate ( |
Ion chromatography (Model: Dionex ICS-1600) | |
Sulfate ( |
Ion chromatography (Model: Dionex ICS-1600) | |
Sodium (Na+), mg/l | Flame emission spectrophotometry (Model: Jenway, PFP7) | |
Potassium (K+), mg/l | Flame emission spectrophotometry (Model: Jenway, PFP7) | |
Calcium (Ca2+), mg/l | Atomic Absorption Spectrophotometer (AAS) (Model: AA-7000, Shimadzu) | |
Magnesium (Mg2+), mg/l | Atomic Absorption Spectrophotometer (AAS) (Model: AA-7000, Shimadzu) | |
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Soil | pH | Glass electrode pH meter |
TDS, g/kg | TDS meter | |
Conductivity (mS/cm) | Conductivity meter (Model: HACH SensION 156) | |
Salinity % | Salinity meter (Model: DDSJ-308A) | |
Fluoride (F-), mg/kg | Ion chromatography (Model: Dionex ICS-1600) | |
Chloride (Cl-), mg/kg | Ion chromatography (Model: Dionex ICS-1600) | |
Nitrite ( |
Ion chromatography (Model: Dionex ICS-1600) | |
Bromide (Br-), mg/kg | Ion chromatography (Model: Dionex ICS-1600) | |
Nitrate ( |
Ion chromatography (Model: Dionex ICS-1600) | |
Phosphate ( |
Vanadomolybdophosphoric yellow color method | |
Sulfate ( |
Turbidimetric method | |
Sodium (Na+), mg/kg | Flame emission spectrophotometer (Model: Jenway, PFP7) | |
Potassium (K+), mg/kg | Flame emission spectrophotometer (Model: Jenway, PFP7) | |
Calcium (Ca2+), mg/kg | Atomic Absorption Spectrophotometer (Model: AA-7000, Shimadzu) | |
Magnesium (mg2+), mg/kg | Atomic Absorption Spectrophotometer (Model: AA-7000, Shimadzu) |
Soil pH was analyzed with a glass electrode pH meter [
Quality control (QC) monitors reagent quality, apparatus cleaning, and accuracy and precision of methods and instrumentation and reliability were implemented daily in the laboratory. Under this QC, blank analysis, replication, internal standard, and certified reference materials were followed properly for each collected soil and water sample for the measurement of salinity indicators. During ion analysis, standard curve was prepared for each single anion at three points of concentration using certified reference material. For every five samples, a reference sample and spiked sample were included to ensure the QC. Ion chromatography, flame photometer, and atomic absorption spectrophotometer were calibrated for every six months and methods of analysis were validated by Bangladesh Accreditation Board (BAB) as per ISO/IEC 17025. All quality assurance was maintained according to the proposed guidelines of American Public Health Association (APHA) [
Description of quality control (QC) for the determination of salinity indicators in water samples across the Kalapara coastal belt in Bangladesh.
Salinity indicators in water | Container | Volume (ml) | Sampling and transport | Preservation | Maximum holding time | Storage | Remarks |
---|---|---|---|---|---|---|---|
Salinity % | Polyethylene plastic bottle | 500 ml | Filled bottle to exclude air | — | Determined on the sampling locations | Analyzed immediately | The meter was calibrated on the day of use |
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Conductivity ( |
Polyethylene plastic bottle | 500 ml | Filled bottle to exclude air | — | Determined on the sampling locations | Analyzed immediately | The meter was calibrated on the day of use |
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TDS, mg/l | Polyethylene plastic bottle | 500 ml | Transported under ice and filled container to exclude air | — | Held for 7 days before analysis | Stored in refrigerator at 4°C | Total dissolved solids (TDS) also known as “filterable residues” |
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pH | Polyethylene plastic bottle | 100 ml | Filled bottle to exclude air | — | Determined on the sampling locations | There was no storage in refrigerator | The meter was calibrated on the day of use |
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Fluoride (F−), mg/l | Polyethylene plastic bottle | 500 ml | Not maintained | — | 7 days | — | — |
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Chloride (Cl−), mg/l | Polyethylene plastic bottle | 500 ml | Transported under ice and filled container to exclude air | — | Analyzed on that day | Stored in ice box at 4°C | — |
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Nitrite ( |
Polyethylene plastic bottle | 200 ml | Transported under ice | — | 2 days | Stored in refrigerator at 4°C | — |
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Bromide (Br−), mg/l | Polyethylene plastic bottle | 500 ml | Transported under ice | — | Analyzed within 7 days | Stored in refrigerator at 4°C | — |
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Nitrate ( |
Polyethylene plastic bottle | 500 ml | Transported under ice | Acidified with HCl to pH < 2 | 7 days with acidification | Stored in refrigerator at 4°C | |
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Phosphate ( |
Polyethylene plastic bottle | 300 ml | Filled bottle to exclude air. Filtered on site (0.45 |
— | 2 days | Freezed ( |
— |
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Sulfate ( |
Polyethylene plastic bottle | 100 ml | Filled bottle to exclude air. Transported under ice | — | 7 days | Stored in refrigerator at 4°C | — |
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Sodium (Na+), mg/l | Polyethylene plastic bottle | 500 ml | Filled container completely to exclude air. Transported under ice | Acidified with nitric acid to pH < 2 | Analyzed within 1 month | Stored in refrigerator at 4°C | Acidified for the determination of other metals in the sample |
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Potassium (K+), mg/l | Polyethylene plastic bottle | 500 ml | Filled container completely to exclude air. Transported under ice | Acidified with nitric acid to pH < 2 | Analyzed within 1 month | Stored in refrigerator at 4°C | Acidified for the determination of other metals in the sample |
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Calcium (Ca2+), mg/l | Polyethylene plastic bottle | 500 ml | Filled container completely to exclude air. Transported under ice | Acidified with nitric acid to pH < 2 | Analyzed within 1 month | Stored in refrigerator at 4°C | Acidified for the determination of other metals in the sample |
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Magnesium (Mg2+), mg/l | Polyethylene plastic bottle | 500 ml | Filled container completely to exclude air. Transported under ice | Acidified with nitric acid to pH < 2 | Analyzed within 1 month | Stored in refrigerator at 4°C | Acidified |
Description of quality control (QC) for the determination of salinity indicators in soil samples across the Kalapara coastal belt in Bangladesh.
Chemical properties | Container | Sampling & transport | Maximum holding time | Storage | Comments |
---|---|---|---|---|---|
Salinity % |
Polyethylene zip lock bag | Transported under ice box | 7 days | Stored in refrigerator at 4°C | Field moist or air dried soil |
Based on the inception meeting, data on salinity affected cropping areas was collected from the Department of Agricultural Extension (DAE) at Kalapara Upazila. Information regarding salinity intrusion on cropping patterns was also gathered from these studies. This data was verified in the discussion with a group of 25 farmers from different cropping areas at Kalapara Upazila with the help of DAE personnel. On the other hand, data pertaining to salinity affected fodder crops for livestock production was collected from the Department of Livestock Services (DLS) at Kalapara Upazila. Similarly, this information was also justified by discussions with the affected livestock farmers from the coastal belt of Kalapara (Tables
Based on the inception meeting, information regarding the number of salinity affected fresh water bodies was noted from the Department of Fisheries (DOF) at Kalapara Upazila. Based on the primary information from DoF, we interviewed a group of people who have been living in the surrounding areas of each of the affected water bodies to get data regarding visible, threatened, endangered, and extinct fish species. We interviewed 50 people from each location; among these, an average of 10–12 were women and the rest were men. They were on average 40–60 years old. The interviewees were involved in diverse professions such as fishing, boating, farming, government officials, and researchers. All recorded information regarding the current status of biological diversity of fish is presented in Tables
Soil and water quality constituents were analyzed through Pearson correlation coefficient using “R” Software, version 3.2.2 (R Foundation for Statistical Computing, Vienna, Austria). Significant levels of correlation between soil and water quality parameters were analyzed for the validation of the data using “R” Software, version 3.2.2 (R Foundation for Statistical Computing, Vienna, Austria).
The percentage of salinity in water was significantly correlated with conductivity, total dissolved solid (TDS), chloride (Cl−), sulfate (
Correlation coefficient and level of significance between salinity indicators of water samples at Kalapara coastal belt.
Parameters | Salinity | Conductivity | TDS | pH | Fluoride (F−) | Chloride (Cl−) | Nitrite ( |
Bromide (Br−) | Nitrate ( |
Phosphate ( |
Sulfate ( |
Sodium (Na+) | Potassium (K+) | Calcium (Ca2+) | Magnesium (Mg2+) |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Salinity % | 1 | ||||||||||||||
Conductivity ( |
0.989 |
1 | |||||||||||||
TDS, mg/l | 0.988 |
0.999 |
1 | ||||||||||||
pH | −0.045 | −0.013 | −0.010 | 1 | |||||||||||
Fluoride (F−), mg/l | 0.282 | 0.262 |
0.251 |
−0.576 |
1 | ||||||||||
Chloride (Cl−), mg/l | 0.982 |
0.995 | 0.992 | −0.027 | 0.242 | 1 | |||||||||
Nitrite ( |
−0.181 | −0.256 |
−0.265 |
−0.311 | 0.392 | −0.257 | 1 | ||||||||
Bromide (Br−), mg/l | 0.524 |
0.524 | 0.515 | 0.385 | −0.025 | 0.509 |
−0.129 | 1 | |||||||
Nitrate ( |
0.052 | −0.047 | −0.034 | −0.286 | 0.275 | −0.084 | 0.490 | −0.097 | 1 | ||||||
Phosphate ( |
0.702 |
0.671 |
0.675 |
−0.245 | 0.380 | 0.665 |
0.401 | 0.330 | 0.306 | 1 | |||||
Sulfate ( |
0.977 |
0.988 |
0.983 |
−0.022 | 0.243 | 0.993 |
−0.307 | 0.535 |
−0.135 | 0.602 |
1 | ||||
Sodium (Na+), mg/l | 0.981 |
0.994 |
0.990 |
−0.044 | 0.252 | 0.999 |
−0.252 | 0.509 |
−0.088 | 0.658 |
0.994 |
1 | |||
Potassium (K+), mg/l | 0.931 |
0.947 |
0.949 |
0.022 | 0.127 | 0.958 |
−0.220 | 0.403 | 0.015 | 0.683 |
0.924 |
0.953 |
1 | ||
Calcium (Ca2+), mg/l | 0.899 |
0.905 |
0.906 |
0.161 | −0.032 | 0.921 |
−0.256 | 0.532 |
0.020 | 0.604 |
0.896 |
0.916 |
0.968 |
1 | |
Magnesium (Mg2+), mg/l | 0.827 |
0.820 |
0.808 |
0.214 | 0.002 | 0.847 |
−0.154 | 0.727 |
−0.085 | 0.584 |
0.843 |
0.843 |
0.830 |
0.909 |
1 |
The soil salinity was significantly correlated with conductivity, Cl−,
Correlation coefficient and level of significance between salinity indicators of soil samples at Kalapara coastal belt.
Parameters | Salinity | Conductivity | TDS | pH | Fluoride |
Chloride |
Nitrite |
Bromide |
Nitrate |
Phosphate |
Sulfate |
Sodium |
Potassium |
Calcium |
Magnesium |
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Salinity % | 1 | ||||||||||||||
Conductivity |
0.999 |
1 | |||||||||||||
TDS, g/kg | 0.999 |
0.999 |
1 | ||||||||||||
pH | 0.506 | 0.503 | 0.504 | 1 | |||||||||||
Fluoride (F−), mg/kg | 0.782 |
0.782 |
0.780 |
0.790 |
1 | ||||||||||
Chloride (Cl−), mg/kg | 0.993 |
0.992 |
0.994 |
0.490 | 0.732 |
1 | |||||||||
Nitrite |
0.738 |
0.735 |
0.735 |
0.495 | 0.497 | 0.775 |
1 | ||||||||
Bromide |
0.618 | 0.618 | 0.622 | 0.707 | 0.877 |
0.587 | 0.227 | 1 | |||||||
Nitrate |
0.752 |
0.754 |
0.753 |
0.616 | 0.914 |
0.691 | 0.226 | 0.883 |
1 | ||||||
Phosphate |
0.816 |
0.818 |
0.814 |
0.058 | 0.587 | 0.785 |
0.557 | 0.357 | 0.577 | 1 | |||||
Sulfate |
0.958 |
0.958 |
0.959 |
0.325 | 0.578 | 0.971 |
0.717 | 0.432 | 0.597 | 0.779 |
1 | ||||
Sodium |
0.988 |
0.988 |
0.990 |
0.436 | 0.695 | 0.996 |
0.733 |
0.566 | 0.688 | 0.7887 |
0.985 |
1 | |||
Potassium |
−0.136 | −0.14242 | −0.134 | 0.572 | 2.040 | −0.071 | 0.281 | 0.098 | −0.223 | −0.596 | −0.167 | −0.119 | 1 | ||
Calcium |
−0.287 | −0.288 | −0.295 | 0.507 | 0.279 | −0.354 | −0.148 | 0.128 | 0.120 | −0.343 | −0.501 | −0.412 | 0.284 | 1 | |
Magnesium |
0.547 | 0.547 | 0.556 | −0.047 | 0.115 | 0.591 | 0.155 | 0.309 | 0.345 | 0.3314 | 0.695 | 0.649 | −0.136 | −0.813 |
1 |
Existing and recommended values of salinity indicators in soil and water samples.
Samples | Chemical properties | Existing average values | Recommended values | ||
---|---|---|---|---|---|
DoE, 1997 [ |
USEPA, 1994 [ |
Horneck et al., 2007 [ | |||
Water | Salinity % | 1.88 | — | — | — |
Electrical conductivity (EC) ( |
322.9 | 300 | — | — | |
TDS, mg/l | 161.56 | 1000 | 500–1000 | — | |
pH | 7.89 | 6.5–8.5 | 6.5–8.5 | — | |
Fluoride (F−), mg/l | 3.65 | 1 | 2 | — | |
Chloride (Cl−), mg/l | 5307.60 | 150–600 | 250 | — | |
Nitrite ( |
0.85 | <1 | 1 | — | |
Bromide (Br−), mg/l | 12.94 | — | — | — | |
Nitrate ( |
4.17 | 10 | 10 | — | |
Phosphate ( |
1.05 | 6 | — | — | |
Sulfate ( |
557.34 | 400 | 250 | — | |
Sodium (Na+), mg/l | 5186.94 | 200 | — | — | |
Potassium (K+), mg/l | 78.89 | 12 | — | — | |
Calcium (Ca2+), mg/l | 49.45 | 75 | — | — | |
Magnesium (Mg2+), mg/l | 38.50 | 30–35 | — | — | |
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Soil | pH | 1.23 | — | — | 6.5–7.5 |
Electrical conductivity (EC) (mS/cm) | 6.688 | — | — | 0.75–4 |
Effects of salinity on crops, fisheries, and livestock at Kalapara coastal belt of Bangladesh.
Crops | Fisheries | Livestock |
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Total cropping areas are 39102 hectare (ha). During Aman season (June to September), 90% of areas are covered by rice. Salinity intrusion is highly visible during dry season (October–May). Cultivation of crops is at an extreme risk as a result of high salinity intrusion. | The number of fresh water bodies recorded at Kalapara coastal area is 18300 with total area of 857 ha. Out of these areas, 2-3% are converted into shrimp culture. Other areas are replaced by saline water fish. Several occurrences of adaptation are ongoing such as introduction of crab fish and Koral and salinity tolerance tilapia fish. | About 200 ha grazing/fodder crop areas have been affected each year due to salinity intrusion. For this reason, food shortage is one of the crucial issues for livestock production in this coastal region. Due to intake of salinity affected fodder crops by livestock, several diseases were found such as diarrhea, skin diseases, liver fluke, loss of body weight, and breakdown of immune system. |
Data were collected from the office of Department of Agriculture and Extension (DAE), Department of Fisheries (DOF), and Department of Livestock Office (DLO) at Kalapar Upazila.
Effect of soil and water salinity on cropping patterns at Kalapara coastal belt.
Description of cropping pattern | Total cultivable land (ha) | Net cultivated land in percentage (2014-15) | Causes |
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Fallow-fallow-T. Aman | 21310 | 54.5 | Soil and water salinity |
Felon-fallow-T. Aman | 6251 | 15.99 | Soil and water salinity |
Pulse-fallow-T. Aman | 5160 | 13.2 | Soil and water salinity |
Watermelon-fallow-T. Aman | 2300 | 5.88 | Soil and water salinity |
Vegetables-fallow-T. Aman | 1200 | 3.07 | Drought |
Pulse-fallow-T. Aman | 381 | 0.97 | Soil and water salinity |
Felon-Aus-T. Aman | 356 | 0.91 | Soil and water salinity |
Boro-fallow-T. Aman | 275 | 0.70 | Soil and water salinity |
Vegetable-vegetable-vegetable | 257 | 0.66 | Drought |
Watermelon-Aus-T. Aman | 200 | 0.51 | Soil and water salinity |
Almond-fallow-T. Aman | 150 | 0.38 | Soil and water salinity |
Green chili-T. Aus-T. Aman | 120 | 0.31 | Soil and water salinity |
Pulse-Aus-T. Aman | 100 | 0.26 | Soil and water salinity |
Wheat-fallow-T. Aman | 100 | 0.26 | Salinity and drought |
Maize-fallow-T. Aman | 100 | 0.26 | Soil and water salinity |
Sweet potato-fallow-T. Aman | 100 | 0.26 | Soil and water salinity |
Pulse-fallow-T. Aman | 90 | 0.23 | Soil and water salinity |
Sunflower-fallow-T. Aman | 80 | 0.20 | Soil and water salinity |
Green chili-Aus-T. Aman | 80 | 0.20 | Soil and water salinity |
Almond-T. Aus-T. Aman | 50 | 0.13 | Soil and water salinity |
Sweet potato-T. Aus-T. Aman | 50 | 0.13 | Soil and water salinity |
Pulse-T. Aus-T. Aman | 50 | 0.13 | Soil and water salinity |
Sesame-fallow-T. Aman | 50 | 0.13 | Soil and water salinity |
Sunflower-Bona Aus-T. Aman | 40 | 0.10 | Soil and water salinity |
Wheat-T. Aus-T. Aman | 35 | 0.09 | Soil and water salinity |
Pulse-T. Aus-T. Aman | 31 | 0.08 | Salinity and drought |
Sweet potato-T. Aus-T. Aman | 30 | 0.08 | Soil and water salinity |
Fresh potato-T. Aus-T. Aman | 30 | 0.08 | Soil and water salinity |
Sugarcane-sugarcane-sugarcane | 21 | 0.05 | Drought |
Garlic-T. Aus-T. Aman | 20 | 0.05 | Soil and water salinity |
Wheat-T. Aus-T. Aman | 20 | 0.05 | Soil and water salinity |
Maize-T. Aus-T. Aman | 18 | 0.04 | Soil and water salinity |
Garlic-T. Aus-T. Aman | 16 | 0.04 | Soil and water salinity |
Vegetable-T. Aus-T. Aman | 15 | 0.04 | Salinity and drought |
Pulse-T. Aus-T. Aman | 15 | 0.04 | Salinity and drought |
Cucumber-T. Aus-T. Aman | 11 | 0.03 | Soil and water salinity |
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Total number of cropping patterns is 36 | Total cropping area 39,102 ha | Total cultivated areas in percentages (100%) | 92% of areas are affected by salinity |
Recorded species of fish at Kalapara coastal belt.
Category | Local name | English name | Scientific name |
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Inland fishes | Bhetki/Koral | Barramundi/Seabass |
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Kalo bujuri | Tengra mystus |
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Tengra |
Striped dwarf catfish |
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Golsha tengra |
Gangetic tengra |
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Rui | Indian Major carp |
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Catla | Calta |
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Mrigal | Mrigal |
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Tara baim |
One-striped spiny eel |
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Baim/Guchi | Striped spiny eel |
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Bele | Tank goby |
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Magur | Air breathing catfish |
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Boal |
Freshwater shark |
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Pabda | Pabdah catfish |
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Koi | Climbing perch |
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Shol |
Banded snakehead |
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Gazar | Giant snakehead |
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Taki |
Spotted snakehead |
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Cheng | Asiatic snakehead |
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Bheda/Meni |
Mud perch |
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Aor |
Long-whiskered catfish |
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Foli |
Grey featherback |
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Chital | Humped featherback |
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Ilish |
Hilsha |
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Chandana ilish |
Toli Hilsha |
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Tit punti | Ticto barb |
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Jat punti |
Spotfin swamp barb |
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Sarpunti | Olive barb |
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Shing | Stinging cat fish |
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Chapila | Indian river shad |
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Khalisha |
Striprd gourami |
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Mola | Indian carplet |
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Dhela |
Cotio |
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Kalibaus | Black rohu |
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|
Darkina |
Rasbora |
|
|
Kakila | Needle fish |
|
|
Chanda | Elongate glass perch |
|
|
Pangus |
River pungus |
|
|
Ek thota |
Halfback |
|
|
Potka |
Gangaetic puffer fish |
|
|
Churi |
— |
|
|
Kuli |
Dusky sleeper |
|
|
Tapasi/muni | Paradise threadfin |
|
|
Lakhua | Indian threadfin |
|
|
Parsia |
Goldspot mullet |
|
|
Poa |
Pama |
|
|
Somudra koi |
Tripletail |
|
|
Rup chanda | Chinese pomfret |
|
|
Tular dandi | Gangetic sillago |
|
|
Kuicha | Gangetic mud eel |
|
|
Kani magur |
Canine catfish eel |
|
|
Rita |
Rita |
|
|
Bata |
Bata labeo |
|
|
Phasa |
Gangetic hairfin anchovy |
|
|
Choukka |
Indian pellona |
|
|
Kachki |
Ganga river sprat |
|
|
Bagha air |
Gangetic goonch |
|
|
Silong |
Silond catfish |
|
|
Salbaim |
Zig Zag eel |
|
|
Chaka | Squarehead catfish |
|
|
|
|||
Exotic fishes | Grass carp | Asian carp |
|
Common carp | European carp |
|
|
Silver carp | Asian carp |
|
|
Thai sarpunti/Raj puti | Firefine barb |
|
|
Tilapia |
Cichlid fish |
|
|
Thai pungus |
— |
|
|
Nilotica |
— |
|
|
Bighead carp | — |
|
|
Mirror carp | — |
|
|
Black carp | — |
|
|
|
|||
Marine fishes | Chitra/Bistara | Spotted butterfish |
|
Java | — |
|
|
Tular dandi |
Lady fish |
|
|
Med |
Gaint sea cat fish |
|
|
Lal poa/Vola | Silver jew |
|
|
Konkon |
— |
|
|
Churi | Ribbon fish |
|
|
Phasa |
Anchovies |
|
|
Datina/Sada datina |
Silver bream |
|
|
Kani magur |
Canine eeltail catfish |
|
|
Tular dandi | Gangetic sillago |
|
|
Kuicha | Gangetic mud eel |
|
|
Kani magur | Canine catfish eel |
|
|
Rup chanda | Chinese pomfret |
|
|
Cheowa |
Torpedo trevally |
|
|
Shaplapata/Haush | String ray |
|
|
Bhangan | Mullet |
|
|
Rekha |
Four barred finger fish |
|
|
Loitta | Bombay duck |
|
|
Foli chanda | Silver pomfret |
|
|
Rup chanda | Chinese pomfret |
|
|
Cheowa |
Torpedo trevally |
|
|
Maitya |
Jack and pompanos |
|
|
Lakhua | Indian salmon |
|
|
Sada poa | Silver jew |
|
|
Gongonia |
Grunting toadfish |
|
|
Amadi |
Pointed tail anchovy |
|
|
Kukurjiv |
Sole |
|
|
Kamot hangor | Requiem shark |
|
|
Bom maitta |
Tuna |
|
|
Bata |
— |
|
|
Ghagra bele |
— |
|
|
Ghagra | Gagora catfish |
|
|
Somudra koi | Tripletail |
|
|
Bhut bele |
— |
|
|
Somudra chela |
— |
|
|
Potka |
— |
|
|
Lambu/Bara poa |
Long jewfish |
|
|
Foton maach | King mackerel |
|
|
Ruppan |
Thread fun bream |
|
|
Moori | — |
|
|
Choukha |
Indian pellona |
|
|
Kawa |
Hard tail |
|
|
Shankhachil | Banded eagle ray |
|
|
Katabukha |
Beardless sea catfish |
|
|
Kuli |
Duckbill sleeper |
|
|
Kamila | Indian pike conger |
|
|
Haturi hangor | Hammerhead shark |
|
|
Tak chanda |
Common pony fish |
|
|
Dahuk |
Walking goby |
|
|
Ilish |
Hilsa shad |
|
|
Chandan ilish | Toli shad |
|
|
Tuna | Yellowfin tuna |
|
|
Ramchosh/Taposi |
Paradise threadfin |
|
|
Khorsula |
Corsula |
|
|
Bhetki/Koral |
Seabass |
|
|
Barguni |
Jarbua terapon |
|
|
Rupsha |
Skipjack tuna |
|
|
|
|||
Prawns | Golda chingri |
Fresh water prawn |
|
Chatka chingri | — |
|
|
Gura chingri | Spider prawn |
|
|
|
|||
Shrimps | Bagda chingri | Giant tiger shrimp |
|
Chaka chingri |
Indian white shrimp |
|
|
Chapra chingri | Oriental shrimp |
|
|
Horina chingri |
Brown shrimp |
|
|
Chali chingri | Yellow shrimp |
|
|
|
|||
Crabs | Shela kakra | Mud crab |
|
Zaji kakra |
Blue swimmer crab |
|
|
Sataru kakra | Swimmer crab |
|
|
Shela kakra | Mud crab |
|
Present status of recorded visible, threatened, endangered, and extinct fish species at Kalapara coastal belt.
Category | % visible | % threatened | % endangered | % extinct | Causes |
---|---|---|---|---|---|
Inland fishes (59) | 45 | 24 | 19 | 12 | Salinity |
Marine fishes (57) | 43 | 21 | 24 | 12 | Cyclone/salinity |
Exotic fishes (10) | 70 | 30 | — | — | — |
Prawns (3) | 67 | — | 33 | — | — |
Shrimps (4) | 50 | — | 25 | 25 | Cyclone/salinity |
Crabs (4) | 75 | — | 25 | — | — |
We know that farmers are reliant on crop and livestock production across the coastal belt of Kalapara Upazila. Through interviews with community members in the study areas we determined threats that included decreases in crop and livestock production. During Aman season (June to September), 100% of the areas are covered by crops. About 200 ha fodder crop areas are affected each year due to salinity. For this reason, food shortage is one of the crucial issues for livestock and other animals. Due to the high dependence on the salinity affected fodder crops, livestock are affected by many negative consequences such as diarrhea, skin diseases, liver fluke, loss of body weight, and breakdown of the immune system (Table
Out of 857 ha water bodies, 2-3% are occupied by shrimp culture which has contributed to the salinity of inland and fresh water bodies across the coastal belt. Other areas have also been replaced by saline water on the Kalapara coastal belt (Table
Different cations and anions are inconsistent in saline soil and water. The degree of salinity effects on crops, livestock, and water bodies in fish may not have the same level of effects on the environment [
Coastal agriculture is based on farmlands, which provide livelihood support for the community [
Salinity has been convenient for shrimp cultivation across the coastal belt, but it has accelerated negative effects on the diversity of fresh water fish. Some of the inland fresh water species have become extinct due to the connectivity with saline water [
An extreme scarcity of salinity free water was recorded in the coastal belt of Bangladesh because of natural disasters such as sea levels rising, cyclones, floods, and land erosion which brought saline water from the sea that mixed with surface and groundwater [
Not only crops and fish have been negatively affected due to the high salt in the coastal belt of Bangladesh (Tables
Array of sea is connected with the inland riverine body. It should have been isolated through an embankment between the bank of the river and the sea. This land could be protected from inundation of saline water through the establishment of an embankment of suitable size. The recommended size should be 5–10 meters higher than the high tide level. Brammer [
The sluice gate is a connection between inland and salt water bodies in the coastal region of Bangladesh. This sluice gate which is placed in the embankment systems is responsible for the control of excess water. This makes it possible to prevent intrusion of saline water during high tide in the coastal belt. This sluice gate across the embankment can remove excess saline water during high tide [
Slight variations in the land lead to salt accumulation in the crop fields. Land should be properly leveled to prevent accumulation of water in the low-lying patches with shallow groundwater tables and to facilitate a uniform drainage system for removing excess water. It will also help to apply irrigation water uniformly in the field during Rabi season (January–March), which will facilitate uniform germination of seeds and better growth of crops. Haque [
Tidal water is generally salty. This water is not useful for the production of crops in the coastal belt. During the rainy season excess rain water should be stored in ponds and canals. Later, this harvested rain water will be valuable for crop irrigation during the dry season. Climate change has caused rising sea levels along the coastal belt. This in turn has contributed to the rise in salinity intrusion in the region. One result of this is a severe scarcity of potable water at the south western coastal area of Bangladesh. This rainwater harvesting system is proposed solution to provide fresh water for crop cultivation and domestic uses during the rainy season across the coastal belt in Bangladesh [
Even though the coastal area is relatively flat, there exist some altitude differences in areas where depths of standing water can reach 10–100 cm. Varieties of cultivars should be selected on the basis of tolerance to standing water and the extent of salinity in the field to maximize productivity of the available land. Utilizing salt-tolerant crops is one of the most important strategies to solve the problem of salinity. Qualitative and quantitative protein synthesis in plants have been altered under these saline conditions. When a plant is subjected to abiotic stress, a number of genes are turned on, resulting in increased levels of several metabolites and proteins, some of which may be responsible for conferring a certain degree of protection from the salinity stress [
Cropping intensity should be modified in slightly saline areas by adopting proper soil and water management practices with the introduction of salt-tolerant crop varieties. During this dry season, salt-tolerant minor cereal crops such as lentil, mung bean, and pea and different vegetables might be cultivated through the proper management of drainage systems [
Groundwater is saline and present at a shallow depth (about 1.0 meter). Keeping lands fallow leads to high salinity in soil due to the evaporation of excessive soil moisture. Therefore, it is recommended to avoid fallowing of lands during Rabi season (winter season). Salt-tolerant crops should be chosen and grown. This can be done by reintroduction of deep rooted perennial plants that continue to grow and use water during the seasons that do not support annual crop plants. This may restore the balance between rainfall and water use, thus preventing rising water tables and the movement of salt to the soil surface [
Since soils in general are poor in fertility with low organic matter content, it is necessary to apply appropriate fertilizers to increase crop production. Potash fertilizer has an added advantage in saline soil. It lowers Na uptake by plants and increases K uptake. Thus K fertilization protects crops from harmful effects of Na. This crop nutrient management is one of the best options to increase the plant productivity in saline soils. For this, an application of potassium sulfate (K2SO4) can improve the plant productivity and nutrient uptake for food crops in a saline environment. It was observed that the uptake and accumulation of nutrients like calcium, magnesium, potassium, and phosphorus increase in plants subjected to K fertilizer application under saline environments [
In many parts of the coastal region, salinity is highly visible. To grow crops successfully in those areas, it is necessary to bring down the salinity by leeching the salts. It is also necessary to decrease the water table level and maintain it below the critical depth to prevent the salt from having an effect on crops. To achieve this objective, a proper subsurface drainage has to be installed to keep the groundwater at least 1.5 meters below the soil surface. Salinity is managed by a combination of vegetation and engineering strategies—designed to create the reduction of water in these areas. The planting of vegetation with high water usage can be utilized to reduce groundwater recharge and to intercept water as it moves through the soil [
Strengthening adaptation capacity requires blending individual skills and household capacity with external institutional supports for technological acceptance. The dynamic geomorphological nature in coastal areas along with spontaneous natural disasters often exceeds the knowledge of the local people and use of available resources to reduce the problems in the long run. Adaptation practice is mostly dependent upon institutional response for promotional activities and to managing observed risks in Bangladesh and less focusing on integrating other social constructions at the community level. Making long-term decisions for coastal adaptation depends on climate change and complexities and levels of stakeholder support [
Coastal adaptation can be reached through adjustment of ecological, social, or economic systems to actual or expected climatic impacts. Social, ecological, and institutional capacities are significantly important to the coastal communities to adapt themselves in an adverse situation. These communities of people need to adapt with the changing environmental conditions caused by salinity. They have been following traditional cropping patterns for crop cultivation across the coastal saline environment [
Introducing fast growing and improved varieties fish across the costal belt might be a way of supplying fresh water fish. Though coastal areas are dominated by groups of fishermen, with the changing environment and extreme events, most of the people are experiencing a decrease in the seasonal fish catch from the sea and rivers in the region. The channel system can secure additional or alternative sources of income through fish cultivation in two seasons of the year. By excavating a single ditch, a family can produce an estimated 200 kg of fish annually which secures their household protein and additional income after consumption. Harvesting of rain water in these ditches also supports regular water supply to plantations on the channel and increases fresh water security as it doubles as a reservoir.
The plantation of the correct varieties of vegetables can provide an immediate opportunity for household consumption in these communities. Different hanging vegetables including country bean, cucumber, bottle, bitter, and sweet gourds (cucurbitaceous vegetables) and other creeper vegetables may be cultivated widely across the coastal belt. This cultivation system will be helpful for supplying needed nutrients during adverse conditions of salinity intrusion across the coastal environment.
Agricultural practice is increasingly constrained with a high level of salinity ingress and frequent and severe impacts of natural disasters in coastal areas. Given the impacts of seasonal water logging and salinity on land and lack of irrigation in dry seasons, alternative cropping practices through use of climate resilient rice varieties have been a vital need for agricultural production in the area. The salt-tolerant rice variety (BR 47) has already been introduced in four coastal districts. Considering lower land productivity, this rice variety has been considered a potential crop in this coastal area. This BR 47 rice variety might be introduced due to its high yield in extreme saline conditions in this coastal region.
Weak water governance systems at the local level are another cause of the salinity increase. Salinity intrusion not only is a natural phenomenon but also is caused by human activities. Numerous human activities—such as untimely water use, unplanned shrimp culture, insufficient or poorly maintained infrastructure, and inadequate management systems—can contribute to salinity intrusion.
A total of 57 major rivers are located in the country of Bangladesh, of which 54 rivers enter from India and 3 rivers from Myanmar [
Local government reforms in Bangladesh have evolved very distinctly according to the needs of the ruling elites [
Bangladesh has a 5,017 km embankment protecting the polders in coastal areas of the Bay of Bengal. The primary goal of launching polderization in Bangladesh was to protect the coastal inhabitants from regular natural disasters and to boost the agricultural production [
Local government has connected with the federal government. Government personnel in the departments of extension, disasters, fisheries, livestock, engineering, and water development boards might have a lack of coordination to be able to implement any of the government policies together. On the contrary, researchers, nongovernment officers (NGOs), and international and national groups have been working without coordination with the national government. Due to the lack of integration between the organizations, proposed activities for the reduction of salinity across the coastal belt have not been substantially implemented throughout the country.
The coastal belt is at an extreme risk due to high soil and water salinity. This salinization in water and soil is the major natural hazard hampering crop and livestock production. This is also producing a negative impact on the diversity of fish across this costal belt. This coastal area in Bangladesh constitutes 20% of the country of which about 53% is affected by different degrees of salinity. In fact, declining land, fish, and livestock productivity with a shift toward negative nutrient balance is among the main concerns for food security problems in the country. Several cations and anions in water and soil such as conductivity, F−, Cl−,
This research is a national issue for Bangladesh. The authors are all working in the Government Institute of Bangladesh. Their job is to conduct research and teaching on the national issues in Bangladesh. For this reason, they do not need to receive approval for sample collection from any authority of Bangladesh. Sampling areas are not indicated as protected or endangered species areas in Bangladesh.
The authors declare that no conflicts of interest exist regarding the publication of this paper.
The authors would like to acknowledge the Laboratory of Environmental Science at Bangabandhu Sheikh Mujibur Rahman Agricultural University (BSMRAU) and Biological Research Division at Soil and Environment Section of Bangladesh Council of Scientific and Industrial Research (BCSIR). The authors are also thankful to the Department of Agricultural Extension (DAE), Department of Fisheries (DOF), and Department of Livestock Services (DLS) at Kalapara Upazila for their support to collect data on salinity issues across the coastal belt of Bangladesh. Finally, they are especially thankful to the Ministry of Science and Technology, Bangladesh, for their valuable funding.