Agricultural Research Management Information System

Home
Research Summary
Search
About Us
- ARMIS
- Brochure
Contact Us
Report
User Request
Data Input
Help
- Operation Manual
  - PDF
  - Video
- Program Area & Commodity
We have reached 37600 number of research entries at this moment.

- Logout

Research Detail

Home
Research
Detail

Effect of Combined Shrimp and Rice Farming on Water and Soil Quality in Bangladesh

Md. Arif Chowdhury
Khulna University, Khulna, Bangladesh

Yahya Khairun
Centre for Marine and Coastal Studies & School of Biological Sciences, Universiti Sains Malaysia, 11800 Pulau Pinang, Malaysia

Md. Salequzzaman
Environmental Science Discipline, Khulna University, Khulna, Bangladesh

Md. Mizanur Rahman
Department of Soil Science, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Salna, Gazipur 1706, Bangladesh

Abstract/ Executive Summary:

This study analyzed water and soil quality and environmental impacts of shrimp farming in the southwestern coastal region of Bangladesh. Shrimp farming in the region is very traditional in nature where two culture systems viz. shrimp–rice and shrimp only are being practiced, which are characterized by lower production, repeated stocking, irregular feeding, and fertilizing. Water quality in both farming systems was found suitable for optimum growth and survival of shrimp (Penaeus spp.). The level of 5-day biological oxygen demand (BOD₅) in both systems even in canal water was within the recommended level provided by the Government of Bangladesh which is less than 5 mg/l. Therefore, effluents of shrimp farms in the study area did not show any nutrient pollution on the surrounding environment. However, saltwater intrusion has caused many problems like loss of agricultural production, reduced availability of fodder for livestock, and fresh water for domestic uses in the coastal region. The findings of this study confirmed that shrimp farming using saline water have long-term effect of soil salinization. As a result, it poses a real threat toward sustainability of coastal shrimp farming as well as coastal development in Bangladesh.

Keywords: Shrimp farming, Effluents, Environmental impact, Salinization, Water and Soil quality

Location: Khulna region, Bangladesh

Start Date: 00-02-2008

End Date: 00-10-2008

Program Area: Farming System

Commodity: Shrimp

Objectives:

To analyze water and soil quality of shrimp farms and impacts of such farming on soil quality and surrounding environment in South-western coastal region of Bangladesh.

Methodology:

Study area: Three subdistricts (Rampal, Mongla, and Shayamnagar) under southwestern Khulna region of Bangladesh were selected for this study to get a good average. The area is situated in the southwestern coastal Bangladesh between 22⁰11' and 22⁰41' latitude and 89⁰0' and 89⁰84' longitudes. The area is under Ganges tidal floodplains agro-ecological zone where most of the lands are being used for shrimp–rice and shrimp-only farming. The world’s largest mangrove forest, the Sundarbans is situated in this region. Water samples collection and analysis For water quality analysis, 5 (five) shrimp–rice farms, 7 (seven) shrimp-only farms, and 4 (four) canals were selected for monthly water sample collection from February to October 2008. The canals were selected from the close vicinity of the shrimp ponds that were used for water source and effluent discharge of the farms. Water samples were collected monthly using a crescent-shaped hollow plastic tube to have water from surface to 30 cm depth from three points of each farm at the same time to make the sample average, and the samples were preserved in plastic black bottles at room temperature (25^oC) for laboratory analysis. Water depth was measured by using a centimeter marking scale. Water parameters such as temperature, transparency, salinity, and total dissolved solids (TDS) were measured immediately after sample collection in the field by using mercury-filled Celsius thermometer, Secchi disk, refractometer, and TDS meter (model no. HI 9635), respectively. Rest of the parameters like pH, dissolved oxygen (DO), and 5-day biological oxygen demands (BOD₅) were analyzed in the water quality laboratory of Environmental Science Discipline of Khulna University. The pH was measured by using the bench pH meter (model no. pH 211) in the laboratory on the day of collection at the earliest possible time. Winkler’s method was applied for analyzing DO and BOD₅. Soil samples collection and analysis: First batch soil samples were collected from 26 spots (13 spots for shrimp-only, 8 for shrimp–rice and 5 for rice-only) at the beginning of the culture period to compare with the soil data reported by Soil Resource Development Institute (SRDI), Bangladesh in 1991. Soil samples were collected by the assistance of SRDI technicians. Final soil samples were collected from the same ponds those were being used for water quality analysis (5 shrimp– rice and 7 shrimp-only) to compare soil quality between two culture systems. Soil samples were collected from the depth of 30 cm at three different locations from the same plot to get an average. Transparent polyethylene bags were used to preserve the samples with proper labeling. The soil samples were dried under shade at room temperature (25^oC) for 2 weeks and then ground and sieved using a 2-mm sieve to make sample suitable for laboratory analysis. After drying, samples were sent to the laboratory and kept at room temperature until completion of chemical analysis. Soil pH was measured using soil water ratio 1:2.5 and electric conductivity using conductivity meter. Organic matter (OM) andtotal nitrogen (TN) were determined by wet oxidation and Kjeldhal method, respectively. The soil phosphorus (P) was analyzed using Bray and Kurtz method for acid soils and lsen’s method for neutral/alkaline soil. Potassium (K) was analyzed using ammonium acetate extraction method. Data analysis: All the data were analyzed using SPSS statistical package version 11.0. Mean water and soil quality parameters were compared using analysis of variance (ANOVA) and least significance difference (LSD) test. Differences were considered significant when P?0.05. Correlations between different water parameters were found out using Pearson’s correlation coefficient (P?0.01). It ranges between 1 for highly positive correlation to -1 for highly negative correlation and 0 indicating a purely random relationship. Water and soil quality index values were also calculated by using Eq. 1 to compare between shrimp–rice and shrimp-only culture system.

Source of Information: Aquacult Int (2011) 19:1193–1206

Article Link (Online Journal):

Funding Source:

Total Budget (Tk.) :

Achievement/Findings:

Shrimp farming in Bangladesh is very extensive in nature utilizing less feed and fertilizers. As a result, discharged effluents from shrimp farms did not show any nutrient pollution in the surrounding environment of the coastal area of Bangladesh. The average BOD₅ was below 5 mg/l which is under the recommended level by the Government of Bangladesh. However, salinity intrusion was found as a major problem in the coastal area for agricultural crop production. Unplanned construction of shrimp farms, inflow of saline water in shrimp ponds, and discharge of farm effluents to surrounding areas changed the local hydrology and boosted up salinity intrusion. Prolonged retention of saline water leads to deposition of salt in soil and increases seepage of saline water into nearby ponds and paddy plots and other water bodies. Most importantly, once excavated and converted a land into shrimp ponds, the coastal environments can not be easily restored to their natural state or function. Though shrimp farming is a more profitable industry over agriculture in coastal areas of Bangladesh in present times, but disease outbreaks and presence of hazardous chemical in shrimp may make the industry unsustainable in the long run. Continued storage of saltwater in shrimp ponds alters the chemical properties of the soil which is unsuitable for agricultural production, and it might be a difficult task to switchback to traditional agriculture in future with these high saline soils resulted from shrimp farming.

Knowledge Management: Journal