Ben Tre Research Articles

Evaluation of machine learning models for mapping soil salinity in Ben Tre province, Vietnam

Evaluation of machine learning models for mapping soil salinity in Ben Tre province, Vietnam

When water policies derail livelihood aspirations: farmers’ agency in everyday politics in the Vietnamese Mekong Delta

ABSTRACT Development of water infrastructure is conventionally prioritised as a pre-emptive intervention policy to address water challenges. In the Vietnamese Mekong Delta, turning a river into a reservoir is touted as a ‘highly-modernist’ water management approach to secure the year-round supply of freshwater for agricultural production. This paper investigates how contested water-livelihood relations emerged from the building of the Ba Lai sluice scheme in Ben Tre Province, and how these processes demonstrate farmers’ agency in everyday politics in seeking solutions for livelihood sustainability. Drawing on a qualitative case study in Binh Dai District, we argue that, while the scheme successfully fulfils the state’s political intention in securing water supply for freshwater-based crop production in coastal zones, it generates contestation between the local government’s attempts to enforce freshwater policies and farmers’ agency in maintaining productive livelihoods. The findings suggest that power asymmetries are embedded within these water-livelihood relations. We find that seeking just solutions that have co-benefits for water management and livelihood sustainability should go beyond business-as-usual water politics by adequately recognising the agency of farmers in sustainable development. The case study offers lessons for navigating the sustainable future of water development projects in coastal deltas and beyond.

Nitrogen-Fixing Purple Nonsulfur Bacteria Originating from Acid Saline Soils of a Rice-Shrimp Farm

The study was conducted to (i) isolate, select, and identify strains of purple nonsulfur bacteria (PNSB), which can fix nitrogen (N), from soil and water in a rice-shrimp integrated system, (ii) to determine the capacity of the selected potent PNSB strains in producing plant growth promoting substances. The isolation resulted in 57 pure PNSB strains from 36 soil samples and 36 water samples of rice-shrimp paddy fields in Thanh Phu - Ben Tre. Among them, 49 strains survived under pH 5.0 conditions, 24 of which grew well under microaerobic light (ML) and aerobic dark (AD) conditions in a basic isolation medium (BIM) containing NaCl 5‰. Two strains (S01 and S06) with the greatest N fixation were identified by 16S rRNA techniques as Rhodobacter sphaeroides. Their N production was 16.9 mg L-1 under the ML condition and 32.1 mg L-1 under the AD condition. Moreover, two R. sphaeroides S01 and S06 strains performed P solubilization at 0.382-2.954 mg L-1 from Al-P, 3.81-4.28 mg L-1 from Fe-P, and 3.87-4.74 mg L-1 from Ca-P, and production of plant growth promoting substances, such as IAA (12.3-15.5 mg L-1), EPS (1.09-1.58 mg L-1), siderophores (10.7-53.6%) and ALA (1.68-2.82 mg L-1) under both the incubating conditions.

Loan accessibility for social housing in Vietnam's Mekong Delta: An empirical study

The purpose of this study is to examine how easily low-income workers can get loans for social housing projects under a Vietnamese government policy. This policy, outlined in Decision 388/QD-TTg by the Prime Minister on April 3, 2023, aims to build at least 1 million apartments for low-income individuals and industrial park workers from 2021 to 2030. The study focuses on four branches of the Vietnam Bank for Social Policy (VBSP) in the Mekong Delta region: Tra Vinh, Vinh Long, Ben Tre, and Soc Trang provinces. The research involved surveying 280 workers who applied for loans at these banks between May 2003 and September 2023. Half of these applicants met the loan criteria, while the other half did not. Using a Binary logistic regression model, the study identified several factors that influence the likelihood of obtaining a social housing loan from VBSP. These factors include the applicant's age, education level, number of dependents, marital status, total income, equity ratio, and the value of collateral. Among these, the total income, value of collateral, and equity ratio were found to have the most significant effect on loan accessibility. Based on the findings, the authors suggest policy recommendations to make it easier for low-income workers to access loans for social housing in the future, enhancing the effectiveness of the VBSP's lending program in the Mekong Delta.

The effect of breeds and rearing system on laying performance and egg quality of local chickens

The study was to identify the reproductive performance of Vietnamese local chickens, named Noi chickens from 36 - 46 weeks of age. The study aimed to determine the effect of breeds and rearing system on laying performance and egg quality of local chickens. The study was a factorial design with 2x2 factors and involved with 120 layers. The first factor was 2 rearing systems (experimental free-range farming system in Tra Vinh province and local free-range farming system in Ben Tre province). The second factor was 2 breeds (egg and broiler purpose). The results showed that egg production rate, laying egg per week were significantly different between breeds and rearing systems (P<0.05) while feed intake was not different. The highest egg production rate recorded at week 44 with 38.42%. For egg quality, yolk diameter, yolk color and yolk index were different breeds and rearing system. It can be recommended that rearing system in Ben Tre province and egg purpose breed was better for egg production and quality.

Deciphering the relationship between meteorological and hydrological drought in Ben Tre province, Vietnam

Deciphering the relationship between meteorological and hydrological drought in Ben Tre province, Vietnam

Application of heat pump drying technology to produce dried mango products from Tu Quy mango (Mangifera india L.), Vietnam, on a pilot scale

In this study, the heat pump drying technique was applied to develop the production process of dried mango from Tu Quy mango sources, Ben Tre province, Vietnam. The experiment was performed in three steps. First, mango slices were treated through the blanching process. Samples were pretreated with sizes from 6 to 12 mm at 80–95°C for 3–6 min, and then the mango slices were soaked in a syrup solution concentration range of 25–40°Bx, citric acid of 0.5–2%, and glycerol of 0.1–0.4% at 35–65°C for 90–180 min. Finally, the samples were dried using a pilot-scale heat pump dryer until the moisture content reached 14–16%. The results showed that the blanching and osmosis processes were carried out under optimal conditions to inactivate the Polyphenol oxidase (PPO) enzyme, obtain maximum polyphenol compounds, and conform to the product appearance. Additionally, the drying process was carried out at 30°C for 1,080 min with the polyphenol content retaining 11.71 mgGAE/gDW—This signifies a successful endeavor in developing production methodologies and expanding the range of mango-derived products. Employing innovative technological processes enhances both the quantity and quality of the products. Moreover, the manufacturing procedure was executed on a pilot device, streamlining the synchronization of large-scale production processes effortlessly. This advancement not only enhances economic value but also addresses the issue of congestion prevalent in the current state of the mango industry in Vietnam.

The reproductive biology of Ellochelon vaigiensis from the Vietnamese Mekong Delta.

The Squaretail mullet, Ellochelon vaigiensis, is a commercial fish species distributed throughout the Indo-Pacific region. This species tolerates wide variations in salinity, having been reported from both freshwater and marine habitats. Although economically significant, there is little information on its reproduction, especially in the Vietnamese Mekong Delta (VMD), where it is heavily extracted. Our study elucidates the breeding pattern, seasonality, first length at maturity, as well as potential and relative fecundity of this species. Fish specimens were collected by trawl nets from November 2020 to October 2021 at four estuarine sites within the VMD. We found this species to be a synchronous spawner, with peaks in reproductive activity from June to September. In the populations we surveyed, there was significant dominance of males (1.26:1.00) based on 942 fish samples (526 males and 416 females). The length at 50% maturity for females was significantly higher than for males at all sites and ranged from 10.6 to 19.3 cm. The diameter of the eggs examined for this species exhibited slight variation, from 0.43 to 0.54 mm. The potential fecundity ranged from 246,254 ± 35,878 to 411,970 ± 54,370 eggs, corresponding to female length and weight of 26.7-32.6 cm and 102.97-234.19 g, respectively. Relative fecundity values were highest at Thanh Phu, Ben Tre (6388 ± 605 eggs), and Dong Hai, Bac Lieu (6461 ± 637 eggs), followed by Tran De, Soc Trang (4729 ± 408), and were found to be lowest at Duyen Hai, Tra Vinh (3117 ± 223 eggs). Information on reproductive behavior in this species has far-reaching impacts on sustainable extractions, stock conservation, and aquaculture.

Extent of saltwater intrusion and freshwater exploitability in the coastal Vietnamese Mekong Delta assessed by gauging records and numerical simulations

Climate change-driven sea level rise has intensified salinity intrusion (SI) in deltas worldwide, posing significant threats to the exploitation of freshwater resources. In the Vietnamese Mekong Delta (VMD), the third largest delta globally, SI is a recurring challenge along the coastline, degrading freshwater resources for agricultural and domestic use and affecting socio-economic development. In this paper, we investigate the spatiotemporal extent of salinity intrusion in the Ben Tre Province, the hotspot of salinity disaster within the VMD. Long-term salinity monitoring data (25 years from 1996 to 2020) has been analyzed, and a 1D (Mike 11) coupled with 3D hydrodynamic model (Mike 3) was developed. Three scenarios were used to investigate the freshwater resources exploitation: (i) the year of investigation (2021), (ii) 2021 to 2030 climate change impacts, considering different annual exceedance probability of the upstream Mekong discharge (i.e., average flow, relatively low, low and very low), and (iii) extreme salinity intrusion (i.e., the 2016 condition). Our results indicated that salinity patterns are well-stratified at the beginning and end of the dry season but well-mixed during the middle period. Furthermore, over the last 25 years, SI has progressively increased and started earlier in the dry season. The modeling scenarios for SI have also revealed a growing complexity in the exploitation of freshwater resources, highlighting challenges related to timing, depth, and geographical location. The exceedance probability scenarios disclosed higher and deeper salinity intrusion along the channel in VMD, ranging from 50 % to 95 %. This poses significant limitations on the feasibility of freshwater exploitation throughout the Ben Tre Province. Under the current trajectory of climate change, the 2030 scenario anticipates salinity intrusion reaching further inland from the 2021 scenario. This is likely to exacerbate the existing challenges in freshwater resource exploitation, even with comprehensive water infrastructure. We, therefore, propose several management strategies to adapt to salinity intrusion: storing freshwater in main rivers, maintaining consistent operation of water infrastructure systems, and encouraging water-saving distribution and exploitation methods. Moreover, we also recommend supporting the development of new drought-tolerant crop patterns.

Ancient Houses in Ben Tre City: A Multifaceted Approach to Preserve Artistic Architectural Heritage and Boost Local Tourism

The ancient houses of Ben Tre city, dating back to the French colonial period, transcend their historical significance to become essential cultural landmarks with global connections. These houses play a pivotal role in safeguarding Ben Tre's artistic and architectural heritage, aligning seamlessly with the vision of a "Green Ben Tre" in contemporary tourism development. Their unique value lies in the harmonious synthesis of material and spiritual elements, fostering cultural exchange and connecting communities worldwide. This article not only presents initial research findings on the preservation and promotion of the rich values encapsulated within Ben Tre's ancient house system but also explores additional crucial technical solutions. Beyond the study of the effectiveness of the Cement-Stabilized Base (CSB) additive in enhancing soil load-bearing capacity, the paper introduces various technical strategies aimed at conserving the artistic architectural heritage. The focus extends to sustainable construction practices, ensuring the longevity of these historical structures. The study emphasizes the urgent need for conservation, acknowledging the imminent threat of demolition faced by some ancient houses in Ben Tre city. It underscores the importance of sustainable tourism development as a key factor in preserving these invaluable cultural assets for future generations.

Enhancing Soil Stabilization in Soft Soils Through The Addition of Sand to Soil-Cement Piles: a Comprehensive Study

Applying a soil-cement mixture to treat soft soil is an effective solution and is being widely applied in many countries around the world. In Vietnam, this method has also been used in many projects, especially in areas with weak soil such as riverside and coastal areas. The soil-cement mixture is made up of natural soil and cement. When cement is mixed with soil, the cement particles will react with water and minerals in the soil, forming a hard bond. The polymerization of this material is equivalent to the curing time of cement. This article focuses on researching the mixing of soil and cement materials to reinforce weak soil in Ben Tre province. Instead of just using cement for reinforcement, the article suggests adding sand and ECO-CSB or ECO-CSSB additives to the soil-cement mixture. Experimental results show that when sand and additives are added, the hardness and load-bearing capacity of the soft ground increase significantly. This method is especially suitable for treating soft soil contaminated with salinity in Ben Tre province. When adding ECO-CSB additives for non-saline soils and ECO-CSSB for saline soils, the amount of cement needed is reduced by 30% while still ensuring uniaxial compressive strength compared to when using only cement.

Characterization and molecular identification of the lumpy skin disease virus in cattle in the Mekong Delta of Vietnam.

Lumpy skin disease (LSD) is caused by a virus belonging to the genus Capripoxvirus, exhibiting clinical symptoms ranging from mild signs to the development of nodules. LSD emerged in Asia and Southeast Asia, including Vietnam, in October 2020 and has since spread throughout the region, resulting in productivity and economic losses. This study aimed to investigate the virus-causing papular dermatitis in cattle from the Mekong Delta region of Vietnam by analyzing its GPCR gene and assessing its evolutionary relationship with sequences in the GenBank database. Blood samples (n = 180) were collected from cattle farms in Ben Tre, Tien Giang, and Tra Vinh provinces. PCR targeting the P32 antigen gene was utilized to detect LSDV presence, and GPCR gene amplification was performed to assess genetic variability. LSDV was detected in 8.33% (15/180) of the samples using PCR targeting the P32 antigen gene. Each sample that tested positive for LSDV demonstrated complete amplification of the GPCR gene. Sequence alignments and phylogenetic analyses of the GPCR gene revealed that Mekong Delta LSDV isolates shared genetic similarities and possessed a 12-nucleotide insertion comparable to strains from China in 2019 and Northern Vietnam in 2020. This study provides preliminary insights into the molecular characteristics of LSDV in cattle from the Mekong Delta region of Vietnam. The observed genetic relatedness to other LSDV sequences from Asia and Southeast Asia underscores the importance of regional surveillance and control measures. These findings contribute to the development of effective strategies for LSDV control and prevention.

Explicating internet usage among farmer households: evidence from Ben Tre Province, Vietnam

Explicating internet usage among farmer households: evidence from Ben Tre Province, Vietnam

Evaluation of the efficiency of coconut dust extract as a corrosion inhibitor for steel reinforcement in concrete by mass spectrometry

Ethanol extraction was employed to isolate a range of compounds from waste products derived from coconut fiber production (coconut dust) in Ben Tre, Vietnam. Phytochemical screening confirmed the presence of flavonoids, tannins, polyphenols, saponins, alkaloids, flobatannins, and anthraquinones among the extracted substances. FT-IR spectroscopy analysis supported the identification of oxygen and nitrogen atoms within functional groups (e.g., O–H, N–H, C–O) and aromatic rings, characteristic of typical corrosion inhibitors. Mass spectrometry investigations indicated that when St3 steel was exposed to an alkaline solution lacking chlorides, a passive film composed of FeOOH formed on the surface. However, upon the addition of NaCl at a concentration of 1.00 mol/dm3, FeCl, FeCl2Cl–, and FeCl3Cl– compounds were detected across the analyzed surface, while peaks corresponding to FeOO– were absent. Remarkably, areas with the highest concentration of particles corresponded to regions exhibiting visible corrosion damage under magnification. The addition of 2.00 g/dm3 of coconut dust extract to the chloride solution prevents the formation of Fe and Cl compounds on the steel surface. Consequently, only peaks characteristic of FeOO– and organic fragments containing oxygen atoms from the extract were observed. Based on these results, it can be assumed that coconut dust extract has the potential to inhibit local (pitting) corrosion of low-carbon steel (St3) when exposed to aqueous alkaline solutions simulating concrete pore liquid containing chlorides. The addition of 2.00 g/dm3 of the extract has been shown to prevent pitting formation at a chloride concentration of 1.00 mol/dm3. Conversely, in the absence of the extract, visible local corrosion damage was observed upon magnification. These findings provide a basis for further exploration of the protective properties of coconut dust extract as an environment-friendly corrosion inhibitor for mild steel in concrete environments containing chlorides.

Hydrodistillation of essential oil from peels of orange (Citrus sinensis) in the Mekong Delta, Vietnam: process optimization and chemical profiling

In this study, essential oils were extracted from peels of orange (Citrus sinensis) by employing hydrodistillation. The materials were collected in Ben Tre Province, Vietnam and the process was optimized by varying some experimental parameters including temperature, water-to-material ratio, extraction time and material size. The obtained essential oil was analyzed by Gas Chromatography-Mass Spectrometry to determine chemical composition. The maximal essential oil yield was determined as approximately 4%, obtained at the following conditions: ratio of water and lemon peels of 3:1 (mL/g), 60 mins and130°C. GC-MS results revealed that Limonene (98.454%), β-Myrcene (0.997%), and α-Pinene (0.549%) are the major constituents in the essential oil.

Utilizing a settling pond-based constructed wetland for the treatment of shrimp aquaculture wastewater – From laboratory to field scale: A case study in Ben Tre Province, Vietnam

The shrimp aquaculture industry, while bringing high economic benefits, simultaneously presents many environmental challenges for many countries, including Vietnam. Our survey results regarding shrimp farming management in 30 representative rural households within Ben Tre province have revealed that 96.7% of wastewater does not meet the allowable standards. Although approximately 76.66% of which is crudely treated by settling ponds, the percentage of substandard wastewater is reduced only to 70%. Unfortunately, >93% of the wastewater is discharged directly into the environment. Faced with that situation, a proposed wastewater treatment option suitable for the rural areas is to utilize settling ponds and indigenous reeds (P.australis and P.vallatoria) to build constructed wetlands (CW). A lab-scale CW was designed to mimic a settling pond on the surveyed farm, which was scaled down to a ratio of 1:500, aiming to validate the efficacy of the CW approach. Accordingly, the P.vallatoria-planted CW with a density of 25 roots/m2 effectively treats the wastewater to meet the permissible standard within 4 weeks. The removal efficiencies of organics, nutrients, heavy metals, and total coliform could reach up to 80, 85, 91, and 41%, respectively. Upon transitioning to the field scale, these efficiencies increased up to 13.09, 18.79, 29.47, and 5%, respectively. More importantly, the treatment time could be shortened to 3 and 2 weeks, respectively, when the wastewater is diluted 1.5 and 3 times, thereby serving as a foundation to upgrade the current farming model from intensive to super-intensive.

Polyphenol Contents, Gas Chromatography-Mass Spectrometry (GC-MS) and Antibacterial Activity of Methanol Extract and Fractions of Sonneratia Caseolaris Fruits from Ben Tre Province in Vietnam.

Plants contain a large number of phytochemical components, many of which are known as bioactive compounds and responsible for the expression of various pharmacological activities. The extract of Sonneratia caseolaris fruit collected in Vietnam was investigated for its total phenolic and total flavonoid contents using methanol solvent and different fractions of S. caseolaris fruits (hexane, ethyl acetate, n-butanol, and aqueous). GC-MS analysis was conducted to identify the bioactive chemical constituents occurring in the active extract. Further, the antibacterial activity was tested in vitro on bacterial isolates, namely Escherichia coli, Staphylococcus aureus, and Bacillus subtilis, using the disc diffusion method on tryptic soya agar (TSA) medium. The methanol extract showed high total flavonoid (82.3 ± 0.41 mg QE/g extract) and phenolic (41.0 ± 0.34 mg GAE/g extract) content. GC-MS of the methanol extract and different fractions of S. caseolaris fruits detected 20 compounds, principally fatty alcohols, fatty acids, phenols, lipids, terpenes derivatives, and carboxylic acids derivatives. A 50 mg/ml concentration of methanol extract had the strongest antibacterial activity on E. coli, S. aureus, and B. subtilis. Furthermore, ethyl acetate, aqueous, and n-butanol fractions inhibited S. aureus and B. subtilis the most. The results of the present study suggested that the fruits of S. caseolaris are rich sources of phenolic compounds that can contribute to safe and cost-effective treatments.

Using Trichoderma asperellum to Antagonize Lasiodiplodia theobromae Causing Stem-End Rot Disease on Pomelo (Citrus maxima).

Stem-end rot disease has been causing damage to the production of pomelos in Vietnam. The cur-rent study aimed to (i) isolate fungal pathogens causing pomelo stem-end rot disease (PSERD) and (ii) discover Trichoderma spp. that had an antagonistic ability against pathogens under in vitro conditions. Fungi causing PSERD were isolated from pomelo fruits with symptoms of stem-end rot disease and collected from pomelo farms in Ben Tre province, Vietnam. Moreover, 50 fungal strains of Trichoderma spp. also originated from soils of these pomelo farms in Ben Tre province and were dual-tested with the fungal pathogen on the PDA medium. The results demonstrated that 11 pathogenic fungi causing PSERD were isolated from the fruit and showed mycelial growth of roughly 5.33-8.77 cm diameter at 72 h after inoculation. The two fungi that exhibited the fast-est growth, namely, S-P06 and S-P07, were selected. ITS sequencing of the S-P06 and S-P07 fungi resulted in Lasiodiplodia theobromae. All the 50 Trichoderma spp. strains were allowed to antago-nize against the S-P06 and S-P07 strains under in vitro conditions. The greatest antagonistic effi-ciency was found in Trichoderma spp. T-SP19 at 85.4-86.2% and T-SP32 at 84.7-85.4%. The two antagonists were identified as Trichoderma asperellum T-SP19 and T-SP32. The selected strains of Trichoderma asperellum were potent as a biological control for fruit plants.

Evaluation of the current status of wastewater management and treatment from super-intensive whiteleg (Penaeus vannamei) shrimp ponds in Ben Tre Province

Evaluation of the current status of wastewater management and treatment from super-intensive whiteleg (Penaeus vannamei) shrimp ponds in Ben Tre Province

Assessment of soil-water vulnerability to salinization in Ben Tre province using DRASTIC model

Soil water in the coastal zones is more vulnerable to salinization. Soil-water vulnerability assessment is an effective tool for soil-water management. This study used the DRASTIC model, which is based on seven factors viz: depth to soil water, recharge, soil-water bearing layer, soil media, topography, impact of root zone, and hydraulic conductivity to evaluate soil-water salinization potentiality of Ben Tre province. The obtained soil-water vulnerability map is divided into three vulnerable zones: low vulnerability zone with 348.59 km2 of total area, moderate vulnerability zone with 1898.77 km2, and high vulnerability zone having 147.64 km2. Moreover, the DRASTIC model was validated by Total dissolved solids (TDS) over the study area. Validation results showed the low vulnerability zone of the moderate saline (TDS = 1,500–7,000 mg/L), while the moderate vulnerability zone of the moderate, high, and very high saline (TDS = 1,500–35,000 mg/L). However, the high vulnerability zone has a very high saline (TDS = 15,000–35,000 mg/L). The study results are of considerable value to land use planning and soil researchers.