Title page no. Table 2.1 Scenario of Shrimp Culture in Southwest Bangladesh 9 Table 2.2 Coverage of Shrimp Culture in Southwest Region of Bangladesh 10. Photo 4.1 Different Types of AWMPs in Kharnia and Sobhana Unions 43 Photo 4.2 Types of Shrimp in Sohana Cultivation Photoharnia4. b. Graded Golda after harvest in Kharnia and Sobhana Unions 47 Photo 4.4 Whitefish harvested in various AWMPs in pre-season 48 Photo 4.5 Operation of community managed sluice gates in Kharnia Union 49 Photo 4.6 Individual water source management in AWMP 50 of type 3.
INTRODUCTION
- Background of The Study
- Objectives of the Study and Possible Outcome The specific objectives of the study are as follows
- Limitations of the Study
- Organization of the Thesis
The exploitation of the salt water is simply controlled by the sluice gates built at the interface between the river and the canal. Two samples (R-1 and V-3) were excluded from multi-criteria analysis (MCA) of different AWMPs due to the above limitations.
CHAPTER TWO LITERATURE REVIEW
Shrimp Cultivation in South Western Coastal Region of Bangladesh
- Environmental impact
- Sustainability of shrimp cultivation
The amount of water required for shrimp culture depends on the nature of the culture system. All of these can have serious implications for the sustainability, not only of shrimp farming itself, but of the rural communities in the coastal areas of Bangladesh.
Present Agro-Water Management Practices and its Sustainability
Prior to RPG agriculture, the southwestern region experienced a period of severe environmental change during the 1960s and 1980s due to the construction of dams and polders that caused permanent waterlogging and increased saltwater intrusion, and farmers were unable to produce agricultural crops (Kendrick, 1994). Following this pattern, a crop of transplanted Aman is grown between September and November during the monsoon season when the water in the river becomes fresh and sweet. From February to August, a crop of shrimp is grown when the water in the surrounding rivers becomes salty.
Although the yield performance of local variety was less (1.9 ton/ha) than HYV (2.5 ton/ha) in Khulna region, farmers preferred to cultivate local varieties in Aman season due to its native characteristics, such as higher plant height, insects and diseases. , waterlogging and salt tolerance ability, tastier and lower production costs (Miah et al., 2004). The findings of the study indicate that more chemical fertilizers were used in MV Boro paddy production per hectare under YRMV paddy farming compared to RPG farming. Although an alternative rice-shrimp system is one of the more environmentally sustainable approaches to shrimp farming, shrimp production in the rice-shrimp system in Bangladesh is low, ranging from 29 to 277 kg/ha (Islam et al., 2004). threat of frequent shrimp crop failures due to disease outbreaks.
The relationship between economic returns from shrimp culture and international market demand could be established by analyzing the history of the development of the shrimp sector industry in Bangladesh. The sustainability of the shrimp sector depends mainly on two functional issues: how much the coastal environment would support shrimp culture.
CHAPTER THREE
MATERIALS AND METHODS
General Description of the Study Area
- Soil sampling
- Water sampling
The salinity of the soil is mainly due to shrimp cultivation with salt water of flood depth of 60-120 cm. The soil classification of the study area falls under the Ganges floodplain and the Ganges tidal floodplain which are medium-low lands. In the study area, it was found that most of the farmers were unable to grow crops throughout the year due to salinity.
The main Bhadra river flows from north to south along the western part of the study area. Due to the variation in rainfall patterns, the water chemistry of a tidal river and the area's surface water fluctuates significantly. The meteorological data for the study area is described in the following table 3.3 to show the climatic condition.
The samples were collected from the main land of the gher which was locally known as gher chatal. Twelve soil and twelve water samples were collected from each union in each of the two seasons.
Collection of Data on Agro-Water Management Practices
7 DO (Dissolve Oxygen) ppm Winkler se method (APHA, 1992) 8 Sodium (Na+) dpm Vlamfotometriese method (Vlam . photometer- modelle PEP 7/C) 9 Potassium (K+) dpm Vlamfotometriese method (Vlam . photometer- modelle PEP) 7/C) 10 Calcium (Ca2+) dpm Titrimetriese method.
Data Analysis
- Multicriteria analysis
The key informant interview was used to collect data from relevant persons from the Upazila Agriculture Bureau and Fisheries Bureau. First, for each farm type, the average value for each of the fourteen soil quality parameters and sixteen water quality parameters was calculated for both the pre-Boro season and the post-Boro season (12 plots). Secondly, the percentage change in the mean value of each soil property and water property during the pre- and post-Boro season of HYV Boro rice cultivation was calculated; and the percent change values of all fourteen soil properties were averaged to obtain the mean soil quality change indicator (MSQI), and the percent change values of all sixteen water properties were averaged to obtain the mean water quality change indicator (MWQI) for each agricultural type.
With the process of standardization, not all effects need to be translated into a common unit of value or meaning. All data in a standardized form was output before using the relative importance of different criteria to evaluate the best strategy. For the linear relationship between two variables x1 (management input) and y1 (rice yield), the Pearson correlation coefficient r was used.
The degree of weight was assigned to the criteria in order of significance level. For a higher degree of significant correlation the given weight was high (weight = 6) and for a lower degree of significant correlation the given weight was low (weight . = 1).
RESULTS AND DISCUSSIONS
Current Status of AWMPs in Dumuria Upazila
- Rice cultivation
- Crop cultivation in the Kharif season
- Management inputs in different AWMPs
In Type-3 AWMP, BRRI Dhan 28 and Hassan were found to have been grown in the Rabi season. In Type-2 and Type-4 AWMPs, golda was grown with bagda in mixed water (photo 4.2). However, in Type-2 AWMP, golda was dominant, and in Type-4 AWMP, bagda was dominant in the Kharif season (mid-May to mid-November).
High yield of whitefish (407 to 448 kg/ha) was also found along with bagda cultivation in Type-3 AWMP. The extensive shrimp culture system in Type 3 and Type 4 AWMPs lasted 3-4 months with occasional feeding. In Type-1 AWMP water was used from STW and in Type-2 AWMP water was used from canal connected to river Bhadra and STW in dry season.
The retained water from Muchikata canal and STW water was used for HYV Boro rice cultivation in Type-4 AWMP from January to mid-April in Jialtoli village of Sobhana Union. In Type-3 and Type-4 AWMPs, the frequency of water exchange was related to the number of low and high tides in the Bhadra River.
Environmental Parameters
- Soil quality
- Water quality
Compared to BARC (2005) it was found from Table 4.3 that a slight increase in soil EC values was shown for non-saline soil in AWMP Type-1 and slightly saline soil in AWMP Type-2, Type -3 and Type-4. Aman rice was grown from mid-July to mid-November before the cultivation of HYV Boro rice (January to mid-April) which may affect available soil N in type 3 and type 4 AWMPs. In the post-Boro season, the same trend of the pre-Boro season was observed, but the sodium content became higher starting from type-1, type-2 and type-3 AWMPs (Table 4.3).
During the postseason of HYV Boro rice cultivation, soil sulfur content was significantly higher (p < 0.15) in type 3 and type 2 than in type 1 AWMP. A similar scenario for soil sodium content was found in type 2 and type 3 agriculture .Sulfate concentration was associated with increased salinity from the pre-Bora season to the post-Bora season in type 2, type 3 and type 4 (Table 4.6).
Temperature, TOC and HCO3- were significantly (p < 0.15) high in post-Boro season in Type-2 due to mixed water of STW and canal water (stored during rainy season) and deposition of bagda shell. In Type-3 and Type-4, the volume of gher water was routinely exchanged every 4–6 days in each lunar cycle.
Evaluation of Different Agro-Water Management Practices
- Environmental consequences
- Multicriteria analysis to evaluate four types of AWMPs
Mean soil quality change indicator (MSQI) and mean water quality change indicator (MWQI) in gher of different AWMPs indicated (Table 4.5 and Table 4.8) the deterioration of environmental quality in the study area. MSQI and MWQI (Table 4.5 and Table 4.8, respectively) in the gher environment may play a key role in bringing mixed shrimp and whitefish into a stressful condition in the study area under HYV Boro rice cultivation. Correlation Table 4.11 shows that management inputs of Kharif season and HYV Boro rice season affected yield of rice in rice-shrimp and whitefish-gher.
But the significant (p < 0.10) correlation with rice yield was found with five management inputs out of eleven management inputs in different AWMPs (Table 4.12). Use of organic fertilizers (UFO) has the highest significant (P < 0.01) positive correlation with rice yield (Table 4.14). In Table 4.13, management criteria have been assigned different weights based on their significant level of correlation with rice yield.
From the evaluation of MCA of four types of AWMPs, Table 4.13 shows that the Type-2 AWMP (total score of 88) is the best practice for agro-water management among the various AWMPs in Dumuria Upazila. In Table 4.13, only the yield of HYV boro rice per pickle was taken as an economic criterion for evaluating AWMPs.
CONCLUSIONS
Conclusions
Multi-criteria analysis of environment (MSQI and MWQI), management (number of crops (NC), irrigation (Irri), water exchange (WEx), use of organic fertilizers (UOF), use of chemical pesticides (UCP), IPM, year of Boro cultivation (YBC), etc.) and economic (yields of HYV Boro rice, golda, bagda and white fish) parameters revealed that the common approach in water management for HYV Boro rice cultivation with a crop rotation by mixed golda, bagda and white fish fish is the best AWMP among four types of existing AWPMs in southwestern coastal region of Bangladesh.
Recommendations for Further Study
BCAS, 2001. The Coastal Shrimp Sector in Bangladesh: Review of the Literature with Annotated Bibliography, Bangladesh Center for Advanced Studies, Dhaka, Beverage, M., Phillips, M., 1993. Socio-economic consequences of shrimp farming in Bangladesh: a case study of Satkhira , Chakaria and Maheshkhali. A conceptual framework for the sustainability assessment procedures of the shrimp aquaculture industry in coastal Bangladesh.
Workshop on Economic, Social and Environmental Implications of Shrimp-Rice Integrated Farming System in Bangladesh. Management of land and water resources for higher productivity of the coastal salt rice fields of Bangladesh. Commissioned by the association of the World Bank, DANIDA, USAID, FAO, DFID with the cooperation of the Bangladesh Ministry of Fisheries and Livestock and the Department of Fisheries, Dhaka, pp.172.
Report prepared for CARE International in Bangladesh with support from the Bangladesh Aquaculture and Fisheries Resource Unit (BAFRU). 18th edition, APHA (American Public Health Association), AWWA (American Water Works Association), WPCF (Water Pollution Control Federation), New York, pp. 4.75-4.117.
ANNEXURE
ANNEX-I
Aungkur Traders-480gm Kloropiris Permanent Neem Tree Plantation on Gher Dykes V-1 Bipolar-25gm, Flaon15-50gm dhe.
