Floodplains Of Bangladesh Research Articles

Assessing the vulnerability of selected coastal informal settlements to floods in the Old Brahmaputra River floodplain, Bangladesh

Urban informal communities in floodplains are particularly vulnerable to flooding and are often overlooked in the disaster response and development strategy. Therefore, determining the vulnerability of such communities is crucial for enhancing resilience and facilitating effective disaster preparedness. This study assesses the vulnerability of three low-income informal urban settlements in the Old Brahmaputra River floodplains of Bangladesh. A total of 15 indicators against three major sub-components of vulnerability (social, physical, and economic) are selected to calculate the index using the analytical hierarchy process and simple average method. Findings revealed moderate vulnerability in all selected communities. ANOVA revealed a significant difference in vulnerability indices among these selected settlements. It was further observed that, unlike community characteristics, the vulnerability levels tend to be influenced by the choice of analytical approach. Based on the study findings, the concerned organizations can implement measures like improving means of risk communication, providing basic amenities, and promoting social capital, which can be utilized to enhance the adaptive capacities of informal settlements.

Performance of kharif maize under conservation tillage in silty clay loam soil

Maize is a major staple food as well as potential cash crop for millions of people, mostly grown in the winter season in Bangladesh under conventional tillage practice. But huge area of cultivable land remains fallow in kharif-1 season in Sylhet region as well as other parts of Bangladesh. Hence, we aimed to identify the best variety and tillage method to grow maize in silty clay loam soil in kharif season. An experiment was conducted to study the performance of six maize varieties in the Kharif-I season (summer) under three tillage methods in silty clay loam soil of Eastern Surma-Kushiyara floodplain (AEZ-20). The experiment was arranged in RCBD with three replications to observe yield contributing traits and yield performance of maize. Among the varieties, BARI Hybrid Maize-16 showed the highest yield attributes and grain yield followed by BARI Hybrid Maize-13 and BARI Hybrid Maize-9. Based on tillage, the maximum number of leaves per plant, cob length and diameter, kernel rows per cob, kernels per row, kernels per cob, highest grain yield, and stover yields were recorded in conventional tillage. Therefore, considering the yield and tillage methods, BARI Hybrid Maize-16 showed the best yield performance under conventional tillage in the kharif-I season in silty clay loam soil of Eastern Surma-Kushiyara floodplain of Bangladesh.

Three Decades of River Bank Erosion and Accretion Appraisal Along Bank Line Shifting Trend in A Transboundary River, Teesta Floodplain of BangladeshThree Decades of River Bank Erosion and Accretion Appraisal along Bank Line Shifting Trend in a Transbounda

As the world's largest delta, Bangladesh possesses distinctive geomorphology dominated by transboundary rivers, making it vulnerable to climatic hazards such as river erosion that causes severe loss of land and other resources. Using four Landsat imageries of 1991, 2001, 2011 and 2021 the current study analyzed the amount and trend of river erosion and accretion on the Teesta Floodplain of Bangladesh for three decades. Findings indicate that the Teesta River experiences severe bank erosion and accretion regularly, causing bank line shifting and thus significant affecting the land-use/land-cover (LULC) change of the area. Between 1991 and 2021, approximately 194 square kilometers of land were eroded, while an equivalent area of land was accreted. Approximately 1072 km2 of agricultural land was converted into other categories, with the settlement area gradually increasing. This trend of changes shows that agricultural land and water-bodies will reduce in the next two decades while barren land and settlement areas will increase. The agricultural lands and barren lands have a greater chance of being occupied by settlement areas. At the same time, crop production patterns will move to those crops that require less water due to the reduction of water-bodies. Reduced flow during the dry season and massive discharge during the monsoon from India's Gajoldoba barrage caused massive siltation and erosion. Comprehensive river management and restoration with an intergovernmental treaty or understanding between India and Bangladesh is required to resolve this crisis in the long run.

Livelihood Impact Due to Riverbank Erosion Among the Affected Households Along the River Jamuna of Bangladesh

The present study examines the impacts of riverbank erosion on locals' lives and livelihoods in a particular area of the Jamuna River floodplain of Bangladesh. Riverbank erosion causes thousands of people to be affected, resulting in damage and loss of crops, cattle, housing structures, and farmland. It also erodes public infrastructures and communication networks significantly. This study undertakes empirical methods (including the open-ended questionnaire with a total of 155 households) to demonstrate the study's findings. The lack of adequate measures is the major factor associated with riverbank erosion in the study area. Land property loss becomes one of the major threats among the surveyed families. Some mitigation measures, such as using Geo bags and concrete blocks to protect the banks and operation of dredging machines to divert the water flow, are observed in the study area to reduce erosion. However, these measures are not bringing any effective solution to the local people’s livelihoods due to the slow ongoing work processes. J. Asiat. Soc. Bangladesh, Sci. 49(2): 179-191, December 2023

Temporal variation, habitat heterogeneity and anthropogenic stressors influencing wildlife communities in an oxbow shaped wetland of lower Ganges floodplain, Bangladesh

Marjat baor is an Ecologically Critical Area located at the lower Ganges floodplain of Bangladesh. A yearlong study wildlife status, community structure and seasonal effect was made following direct field observation in the Marjat baor. A total of 186 vertebrate wildlife species (14 amphibians, 21 reptiles, 131 birds and 19 mammals) were recorded with 9402 individuals. Wetland habitat specialist species were abundant in the community where, Dendrocygna javanica was at the top (5.85%). Herpetofauna showed more uneven distribution than the other animal groups. Due to the richness of migratory birds, seasonal variation showed the highest number of unique species in winter season. A significant difference observed between the community structure of human-dominant and non-dominant landscapes in the ANOSIM test (R = 0.146, p <0.021) and NMDs plot. Floating plant and homestead forest around the baor held the maximum wildlife species. Species richness (F=11.334, p=0.0009) and abundance (F=68, p= 0.0021) differed significantly among the five microhabitats of the study area. The presence of eight threatened wildlife species was noticed in the study area. Anthropogenic stressors causes existential crisis for wildlife. It is revealed that, the community-based conservation may be helpful for conserving the wildlife species in the study area. This study may play a significant role in taking future conservation initiatives. Biodivers. Conserv. Bioresour. Manag. 2023, 9(2): 83-98

An Experimental Study of Fish Movement with Turbulent Kinetic Energy along the Pools of A Vertical Slot Fish Pass

Bangladesh is a land of river which is situated in the delta of the Ganges-Brahmaputra-Meghna (GBM) Rivers which are three of the largest rivers of the world. These rivers provide an arterial transportation network for fish movement. Fish migration depends on flow characteristic and surrounding flood plain connected to rivers. In recent time for flood control in monsoon and water storage in lean period a lot of structure has been built along and across the river [77]. As a result the natural sequence of flooding in floodplain of Bangladesh, food chain and life cycle of natural fish and other aquatic species has become under sever threat [64]. In this research an experimental approach has been carried out to understand the turbulence structures of the flow inside a laboratory flume with different local fish species. The structural set up consists of an adverse slope of 6% followed by a mild slope of 3.4%. The adverse slope is 2.54 m in length and the mild slope is 4.45 m in length. Total nine sets of experiments have been conducted. For each set of experiments, data points were distributed on a 10 cm (in the longitudinal direction) x 10 cm (in the transverse direction) grid at 0.6 hydraulic depth and 10 cm (in the longitudinal direction) x 20 cm (in the transverse direction) grid at 0.4 and 0.8 hydraulic depth. In this experimental setup turbulent kinetic energy and fish movement in all four pools will be observed. This experimental study consists of three types of fish species; Rui (Labeo rohita), Catla (Giberlion catla) and Mrigel (Cirrhinus mrigala) of fry size (1-2 cm body length), fingerline size (7-10 cm) and juvenile size (10-20 cm) have been selected for studying. The flow from slot travels through the center of the pool to the next slot with two recirculation region on either side of the jet. At the pool opening the flow appear almost in the form of a shooting jet. There are similarities with turbulence characteristics in each case. Fishes have avoided high turbulent kinetic energy area in the contour map. The comparison shoes the area with low turbulent kinetic energy was most suitable for fishes to pass the pools or taking rest inside the pools. The results may be useful insight on the turbulence characteristics of flow in the vertical slot fish pass and can be used to study fishes characteristic and also for guidance in the design of fish pass in the future.

Morphology and land use change analysis of lower Padma River floodplain of Bangladesh.

Bangladesh, the largest delta in the world, is situated over the flow of more than 700 rivers. The Ganges is a transboundary river, and it takes the Padma after meeting Jamuna near Aricha. The Padma River's morphology and hydraulic parameters are so dynamic that it erodes a large portion of land every year. However, the situation of erosion has been very threatening since 2014 which is almost the same period when the construction of the Padma Bridge started. Our Study on the erosion-accretion rate and bar dynamics of the selected reach of Padma River shows that the downstream right bank of this river lost around 134.85 sq. km of land between 2003 and 2021. The total bar area has also increased to 76.8%. Land use land classification (LULC) analysis was done for the years 2003, 2009, 2015, and 2021 to predict how the river might act in the future. For this prediction, artificial neural network (ANN) system has been used, and the predicted land use map was generated for 2027. The current kappa validation was 0.869, and the accuracy of the prediction was 87.05%. This study aims at analyzing the current morphological condition and its connection to the construction of the Padma Bridge and also predicts how the lower Padma River might act in near future. According to the study findings, in absence of prompt and appropriate measures, this country is highly susceptible to experiencing catastrophic consequences.

Response of Sulphur and Boron on Growth, Yield Traits and Yield of Boro Rice (BRRI dhan28) at High Ganges River Floodplain of Bangladesh

Response of Sulphur and Boron on Growth, Yield Traits and Yield of Boro Rice (BRRI dhan28) at High Ganges River Floodplain of Bangladesh

Integrated assessment of flood risk in Arial Khan floodplain of Bangladesh under changing climate and socioeconomic conditions

AbstractIn the assessment of flood risk, the future flood hazard due to climate change is often tied to the present socioeconomic conditions. This makes an implicit assumption that the drivers of risk, other than the hazard, remain constant with time. Therefore, such risk assessment does not provide a realistic outlook for devising plausible mitigation strategies and plans. In this study, flood risk was assessed from an integrated perspective by considering both physical hazard, and socioeconomic exposure and vulnerability—all changing with time. The flood hazard in the Arial Khan River floodplain in the southcentral Bangladesh was simulated with a two‐dimensional hydrodynamic model, and the exposure and vulnerability were projected using different statistical techniques. Principal component analysis was conducted to assign weights to the indicators of hazard, exposure, sensitivity, and adaptive capacity. The results show that the flood depth, duration, and extent would increase from the baseline to 2080s under regional concentration pathway (RCP) 2.6 and RCP 8.5 scenarios. The sensitivity and vulnerability would decrease, reflecting an improved adaptive capacity. The low‐risk areas could increase from 62% in the baseline to 85%–91% in 2080s depending on the RCPs. The approach followed can be applied elsewhere in developing countries, particularly in riverine floodplain settings.

Livelihood status of small-scale fishermen and determinants of their income: Insights from north-eastern floodplains of Bangladesh

The small-scale fishermen in the north-eastern floodplains are one of the most vulnerable communities of Bangladesh due to their limited income. This study assessed their livelihood status using a sustainable livelihood framework and employed a multiple regression model to evaluate factors influencing their earnings. Primary data were collected from fishermen’s households in Tanguar Haor and Hakaluki Haor through direct interviews. Results revealed that these households lacked human capital, had poor sanitation facilities and suffered from frequent diseases. Their income is very limited as they lack training on other socioeconomic activities to complement their livelihood grounded on fishing. Hence, their financial capital was very deficient and ranked lowest among other livelihood capitals. Fishermen’s major physical assets were the boats used for group and individual fishing. These small-scale fishermen had limited involvement with local administration, and around half of them were members of various NGOs. Women of these households had low participation in fishing or other income activities. The income of the fishermen was influenced by their age, fish catch per day, training and NGO membership. To increase the earnings and improve the livelihood status of small-scale fishers in the floodplain, this study suggests providing training on complementary income generating activities, improving sanitation facilities and providing additional government and non-government support.

Foliar fertilization of micronutrients on the performance of zucchini squash (Cucurbita pepo) under the Old Meghna Estuarine Floodplain of Bangladesh

Zucchini squash is a popular vegetable linked to many health benefits. Micronutrients although used in a small quantity, play a significant role for optimal plant growth and development however, little is known about foliar feedings of micronutrients on this crop. Therefore, the current research was conducted during 2020 to evaluate foliar micronutrient treatments viz., boron (B), zinc (Zn), silicon (Si), chlorine (Cl), and their combination on growth and yield-related attributes of ‘zucchini squash cv. Surma F:‘. The 12 micronutrient treatments were untreated control, 0.2% boron, 0.2% ZnSO4, 0.2% SiO2, 0.2% NaCl, 0.2% boron + 0.2% ZnSO4, 0.2% boron + 0.2% SiO2, 0.2% boron + 0.2% NaCl, 0.2% ZnSO4 + 0.2% SiO2, 0.2% ZnSO4 + 0.2% NaCl, 0.2% SiO2 + 0.2% NaCl, and mixture of 0.2% boron + 0.2% ZnSO4 + 0.2% SiO2 + 0.2% NaCl. Eight out of 16 parameters viz., stem length (38.94 cm), stem diameter (3 cm), number of leaves (25.64), length of the largest leaf (30.24 cm), length of plant canopy (133.65 cm), number of marketable fruits (6.54), yield plot−1 (18.76 kg) and total yield ha−1 (46.89 tons) was meaningfully influenced with the foliar spray of the treatments whereas the combination of 0.2% boron and 0.2% ZnSO4 was found to relatively be better regarding growth and yield-related attributes of zucchini squash. The results suggest that foliar spray of micronutrients might play significant role in zucchini production.

Predicting Current and Future Potential Distributions of Parthenium hysterophorus in Bangladesh Using Maximum Entropy Ecological Niche Modelling

Parthenium weed (Parthenium hysterophorus L.) is among the most noxious invasive alien plant species, which can pose a threat to agro- and native-ecosystems. Despite potential parthenium infestation risks at the south-western regions of the Ganges–Brahmaputra floodplains of Bangladesh, no studies exist that document parthenium infestation. Using field surveys and a maximum entropy (Maxent) modelling approach, the present study tries to address the problem in the concerned region comprised of five Districts: Jashore, Jhenaidah, Chuadanga, Meherpur, and Khustia. The results revealed high infestation in the Jashore, Jhenaidah, and Chuadanga Districts, mainly along roadsides, in grasslands, and in fallow and cropped fields. The greatest abundance of the weed (ca. 30 plants m−2) occurred at the Indian border area, suggesting cross-border spreading, possibly through the linking road systems. Furthermore, we found that under both low and high emissions scenarios (Representative Concentration Pathways 2.6 and 8.5), parthenium weed suitability areas were likely to expand, suggesting an increased threat to the agro-ecosystems of Bangladesh. The present study is the first attempt to survey and model potential parthenium weed distribution affecting one of the major hubs of agricultural production in Bangladesh. The findings of this study can help land managers to make judicious decisions towards the future management of these agro-ecosystems.

Efficacy and Economics of Different Weed Control Practices in boro Rice under High Ganges River Floodplain of Bangladesh

Weed management practices are crucial for controlling weeds as they reduce yield, increase the production cost as well as deteriorate the grain quality. So, an experiment was conducted at Monirampur, Jashore, Bangladesh during July 2020 to June 2021 to find out the appropriate weed management practices in boro rice. BRRI dhan29 was selected as planting material to see the effect of seven different weed management practices such as no weeding, pre-emergence, post-emergence, pre-emergence followed by (fb) hand weeding (HW) at 40 DAT, post-emergence fb HW at 40 DAT, pre-emergence fb post-emergence and two HW at 20 and 40 DAT following single factor randomized complete block design (RCBD) with three replications. The study revealed that Poaceae and Cyperaceae contributed more weeds among 15 different families. Monochoria vaginalis, Fimbristylis miliacea, Echinochloa crus-galli, Cyperus rotundus and Alternanthera sessilis were more abundant among 34 weed species. The highest weed density (98.22 m−2 ) and dry weight (51.36 g m−2 ) were found in no weeding condition but that of the lowest value (weed density: 9.93 m−2 and dry weight: 3.59 g m−2 ) was observed in pre-emergence fb one HW at 40 DAT. The highest grain yield (6.52 t ha-1 ), net income (91571 Tk ha-1 ) and B:C ratio (1.9) were recorded in pre-emergence fb HW at 40 DAT followed by pre-emergence fb post-emergence treatment. The lowest value of grain yield (3.29 t ha-1 ), net income (12290 TK ha-1 ) and B:C ratio (1.14) were found in no weeding treatment. As per results, it can be concluded that pre-emergence fb HW at 40 DAT has been revealed as the best weed management practice for BRRI dhan29.

An integrated flood risk assessment approach based on coupled hydrological-hydraulic modeling and bottom-up hazard vulnerability analysis

Accurately quantifying and assessing the flood risks is critical for flood hazard mitigation and prevention. This study proposed a new integrated flood risk assessment framework to map flood risk, hazard and vulnerability by coupling the HEC-HMS hydrological model, the HEC-RAS 1D and 2D hydraulic models, and a bottom-up hazard vulnerability analysis. The Old Brahmaputra River floodplain of Bangladesh, a flood-prone region, was chosen as a case study. The coupled hydrological-hydraulic model shows a comparable robust performance in both calibration and validation periods with Nash-Sutcliffe efficiency coefficient = 0.93 (0.81), coefficient of determination = 0.95 (0.89), and percent bias = −1.17% (2.40%) for the calibration (validation) period. Our results indicate that the assessed risk levels are roughly consistent with the overall property distribution and flood-hazard potential in the study area. The proposed framework and associated findings are valuable for developing adaptation strategies and early-warning systems to reduce flood impacts in the future.

Flood susceptibility mapping in Brahmaputra floodplain of Bangladesh using deep boost, deep learning neural network, and artificial neural network

Floods are considered one of the most destructive natural hydro-meteorological disasters across the world. The present study attempts to assess flood susceptibility of the Brahmaputra floodplain of Bangladesh using Deep Boost, Deep Learning Neural Network, and Artificial Neural Network. Primarily, flood inventory maps were prepared from fieldworks and satellite image classification. Consequently, the flood locations were segregated into 70% training and 30% validation samples randomly for running the models and validating the models, respectively. The complete procedure is designed to be considered 12 flood conditioning criteria under four relevant components. The efficiency assessment of DLNN, DB, and ANN models using validation data through the area under the curve (AUC) reveals that DB demonstrates higher accuracy (AUC= .917) than DLNN (AUC = .901) and ANN (AUC= .895) approaches. Therefore, proposed susceptibility mapping approaches are efficient in assessing flood susceptibility accurately and can be implemented in other flood-affected regions.

Climate change impact on the distribution of Tossa jute using maximum entropy and educational global climate modelling

AbstractTossa (Corchorus olitorius L.) is a significant cash crop, cultivated commercially in the lower flood plain of Bangladesh. The climatic regimes in Bangladesh are changing as well as the world does. However, this species is threatened by climate change. Occurrences of data on threatened and endangered species are frequently sparse which makes it difficult to analyse the species suitable habitat distribution using various modelling approaches. The current paper used maximum entropy (Maxent) and educational global climate model (EdGCM) modelling to predict and conserve the suitable habitat distributions for Tossa species in Bangladesh to the year 2100. Nine environmental variables, 239 occurrence data and two Representative Concentration Pathway scenarios (RCP4.5 and RCP8.5) were used for the Maxent modelling to project the impact of climate change on the Tossa distributions. Furthermore, the EdGCM was used to study the climatic space suitability for the Tossa species in the context of Bangladesh. Both of the climatic scenarios were used for the prediction to the year 2100. The Maxent model performed better than random for the Tossa species with a high AUC value of 0.86. Under the RCP scenarios, the Maxent model predicted habitat reduction for RCP4.5 is 2%, RCP8.5 is 9% and EdGCM is 10.2% from the current localities. The predictive modelling approach presented here is promising and can be applied to other important species for conservation planning, monitoring and management, especially those under the threat of extinction due to climate change.

Drought dynamics of Northwestern Teesta Floodplain of Bangladesh: a remote sensing approach to ascertain the cause and effect.

Drought is an affliction for a region that primarily depends on agriculture as economic activity. Commonly monitoring and characterizing of drought is performed by only analyzing the meteorological aspect, assuming precipitation as the primary source of water. However, in riverine Bangladesh, this can lead to an erroneous conclusion, as there is a multitude of available water sources. Consequently, in this study, vegetation condition (Standard Vegetation Index), soil moisture (Soil Moisture Index), and precipitation (Standard Precipitation Index) are separately investigated from 2003 to 2019, in the Northwestern Teesta floodplain. Subsequently, statistical regression analysis is performed to determine the relationships between different aspects of drought. In addition, information obtained from field visits and expert opinions has also been assimilated. Analysis of vegetation and soil moisture condition presents a progressively improving scenario. However, SPI shows an incessant decline in meteorological drought conditions, especially after 2007. Evidently, regression analysis does not provide any indication of an interrelationship between the studied agricultural and meteorological parameters. Presumably, this absence is instigated because the study area is highly irrigated as the groundwater table is suitably near the surface and the existence of nearby Teesta river allows for the utilization of surface water. Moreover, the cropping pattern is shifting toward crops that require much less water and to places where soil moisture is scarce. Thus, this study addresses the gap in knowledge regarding the nature of agricultural drought and the dynamics of different aspects of drought which will be invaluable for the water management and agricultural policy in the study area as well as other regions with a similar backdrop.

Observing the impacts of 1950s great Assam earthquake in the tectono-geomorphological deformations at the Young Meghna Estuarine Floodplain of Bangladesh: evidence from Noakhali Coastal Region

The 1950s great Assam earthquake (GAE) is considered the sixth largest earthquake of the twentieth century in South Asia caused by a collision of two continental plates. This earthquake affected the whole eastern half of the Indian subcontinent and significant tectono-geomorphological deformations were observed at the final course of the Ganges-Brahmaputra-Meghna (GBM) river processes. This is especially the case in the Young Meghna Estuarine Floodplain (YMEF) areas, which have rarely been investigated and documented. Thus, the present study examined the massive geomorphic changes and regarded the configuration changes of the YMEF area immediately after the event, along with its recent aspects. Several direct field surveys together with Focus Group Discussion (FGD), and Key Person Interview (KPI) were conducted within the study area from September 2018 to December 2019. The findings of these research initiatives were augmented by analyzing historical toposheets (1942 and 1964) and multi-temporal Landsat satellite imageries (1975–2019) of the region following appropriate research methodologies. Techniques of remote sensing (RS) and GIS integration were also implemented in a robust way to measure the sinuosity index (SI) of the Meghna River (MR) course that helped to identify the tectonic influences, geomorphic changes, and neotectonics of the study area. The study reveals that as a consequence of this devastating 1950s earthquake, the course of the mighty MR was severely distorted which resulted in a significant reduction of the water flow within its YMEF section. The findings of this study suggest massive configuration changes of the landmass and river course shifting due to this colossal earthquake event. The study also indicates the presence of considerable geomorphic instability along with extensive erosion, deposition, and bank line shifting of the river within the study area during the recent period.

Probiotic supplementation for enhanced growth of striped catfish (Pangasianodon hypophthalmus) in cages

At present, the application of probiotics in aquaculture is gaining wide acceptance for its beneficial effect on fish production. This study focused on evaluating the potency of a commercial multi-strain probiotic on mean growth, feed utilization parameters, yield and survival for profitable cage culture of striped catfish, Pangasianodon hypophthalmus at haor floodplain of Bangladesh. The present study was designed using five treatments (n = 3) in which the fishes were fed commercial pellet diets enriched with 0 % (Control – P0.00), 0.1 % (P0.10), 0.15 % (P0.15), 0.2 % (P0.20) and 0.25 % (P0.25) probiotic. kg−1 feed for 12 weeks. End of the culture period, the fish groups fed probiotic supplemented diets exhibited significant improvement in growth parameters. Weight gain, survival rate, relative growth rate, specific growth rate and protein efficiency ratio were significantly (P < 0.05) higher in P0.20 (808.44 ± 3.67 g, 96.71 ± 0.16 %, 1496.12 ± 2.69 %, 3.08 ± 0.01 % and 3.03 ± 0.01) compared to P0.00, P0.10 and P0.15. The feed conversion ratio significantly (P < 0.05) decreased in P0.20 (1.21 ± 0.01) than other treatments. Significantly (P < 0.05) higher production of P. hypophthalmus was attained in P0.20 (17.20 ± 0.05 kg.m−3), which ultimately boosted gross revenue. The highest benefit-cost ratio was obtained from P0.20 (1.54 ± 0.00). The growth and economic parameters did not exhibit any significant difference between P0.20 and P0.25. However, minimal probiotic inclusion is preferable for its reduced input cost. The overall results indicated that 0.2 % dietary probiotic supplementation hones the growth, yield and survival for profitable floodplain cage culture.

On-Farm Evaluation of Orange Fleshed Sweet Potato Varieties Under Acidic Soil of North-East Region in Bangladesh

An on-farm trial with four orange fleshed sweet potato varieties viz. BARI Mishti Alu-4, BARI Mishti Alu-8, BARI Mishti Alu-12, BARI Mishti Alu-13 including local check (Muli Alu) were evaluated at farming system research and development (FSRD) site, Jalalpur, Sylhet, Bangladesh during rabi season for two consecutive years (2016-2017 &amp; 2017-2018) under Surma‐Kushiyara Floodplain of Bangladesh. The experiment was laid out in a randomized complete block design (RCBD) with six dispersed replications. The results revealed that the genotypes varied considerably in tuber root yields and yield attributing characters. Considering the average tuber root yield performance orange fleshed sweet potato varieties performed better than local variety (Muli Alu). However, among the varieties under studied BARI Mishti Alu-12 produced higher roots yield (40.63 t ha-1) than the other tested varieties. Considering economic return, the highest gross margin (Tk. 5,65,110 ha-1) and benefit cost ratio (5.50:1.00) was also obtained from sweet potato var. BARI Mishti Alu-12 and the lowest returnfrom var. BARI Mishti Alu-4 with benefit cost ratio of 3.54. Though the local cultivar (Muli Alu) produced lower root yields but it provided considerable gross margin (Tk.3,76,240 )and BCR (3.99:1.00 ) which closed to BARI Mishti Alu-12. It is due to higher demand of local cultivar with high price in the local market. Therefore, the genotypes BARI Mishti Alu-12 and local cultivar (Muli Alu) were found suitable for their better growth and yield under the acidic soils&#x0D; Bangladesh Agron. J. 2018, 21(2): 59-65