Science Journal of Agriculture and Environment)

STUDY ON THE MORPHOLOGICAL CHARACTERISTICS OF SHAN TUYET ANCIENT TEA TREES IN DONG PHUC COMMUNE, THAI NGUYEN PROVINCE

2026-01-06T16:10:33+07:00

Shan Tuyet ancient tea trees in Dong Phuc commune exhibit vigorous growth, large woody stems, and broad canopies. Branching occurs at heights ranging from 116.3 to 143.3 cm, with branch angles between 36.8° and 74.2°, and canopy forms varying from spreading to semi upright or upright. Stem circumference ranges from 67 to 117 cm, with medium branch density. Leaves measure 39.43 - 109.73 cm² in area, with rough lamina, shallow serrated margins, and green to light, medium or dark green coloration. Buds are light green, 8.6 - 13.4 cm in length, weighing 1.98 - 2.43 g, and covered with a moderate density of trichomes. Flowers bear 5 - 7 petals, white to pink in color, with diameters of 2.60 - 3.33 cm, and 67 - 108 stamens. Fruits are relatively small (1.82 - 2.49 cm), containing 2 - 4 seeds, with seed coats ranging from brown to dark brown and variable thickness. Several individuals (NB - 10, PP - 5, NB - 11) possess relatively larger leaves, suggesting higher photosynthetic potential. The observed morphological diversity among trees reflects underlying genetic variation and ecological adaptation, providing a valuable basis for conservation and sustainable utilization of Shan Tuyet genetic resources.

PATHOGENICITY OF FOUR SPECIES OF ENTOMOPATHOGENIC FUNGI TO Sitophilus oryzae (Linnaeus) ADULT IN THE LABORATORY CONDITION

2026-01-06T16:14:39+07:00

Study on pathogenicity of four species of entomopathogenic fungi, Cordyceps javanica, Beauveria bassiana, Beauveria amorpha and Metarhizium anisopliae, against Sitophilus oryzae adult of the stored-grain insect pests was evaluated under laboratory conditions. Bioassays were conducted by introducing 10 Sitophilus oryzae adult in plastic box (13 x 10 x 10cm) containing 50 g of rice and 2 g of entomopathogenic fungi at temperature of 25 ± 1^oC and humidity of 70 ± 2% RH. Mortality and mycelial extrusion was monitored at 5 day intervals until 35 days following treatments. Evaluate the pathogenicity of four species of entomopathogenic fungi on Sitophilus oryzae adult based on five parameters: Percent insect mortality, median lethal time, percent mycelial extrusion, fungal developmental cycle and spore production. Research results have been evaluated and selected Cordyceps javanica for potential application of biocontrol of Sitophilus oryzae: Percent insect mortality 86.67 ± 2.46%; median lethal time (LT₅₀) 12.15 ± 0.54 days; percent mycelial extrusion 69.23 ± 1.63%; developmental cycle duration 17.43 ± 0.87 days and spore production concentration 2.3 x 10⁷ (spores/insect).

CHARACTERISTICS OF SALINIZED ALLUVIAL SOIL FOR POMELO CULTIVATION IN GIONG TROM DISTRICT, BEN TRE PROVINCE

2026-01-06T16:18:23+07:00

The aims of the study was to determine the morphological and physiochemical characteristics of soil profiles for pomelo farming in Luong Hoa commune, Vinh Long province. The morphological description was done according to the Munsell color chart and the chemical analysis was conducted Can Tho University. The morphology of the pomelo soils belonged to deposited alluvial soil, with gley horizon and slight salinization and was classified as Hyposali Gleyic Fluvisols. The chemical features showed the pH_H2O and pH_KCl of 4.47 - 5.68 and 3.64 - 4.82 in the surface horizon, respectively. Simultaneously, the Al³⁺ toxicity was moderate with a mean of 2.41 - 7.96 meq/100 g. The available nitrogen and soluble P contents in the soil were 13.0 - 63.0 mg/kg and 39.2 - 547.8 mg/kg, respectively. However, the contents of Al-P, Fe-P and Ca-P were high in the surface horizon with corresponding values of 273.6 - 655.0, 63.4 - 541.5, 122.5 - 229.1 mg/kg. The organic matter content and cation exchange capacity in the soil ranged from extremely low to moderate. Ultimately, improvements should be made in pH, EC and organic matter in pomelo orchards.

ISOLATION AND IDENTIFICATION OF IAA (Indole–3-Acetic Acid) - PRODUCING Rhizobacteria FROM ORCHID NATIVE SPECIES

2026-01-06T16:21:34+07:00

In this study, 44 bacterial strains were isolated from the roots of seven native orchid species cultivated in Ho Chi Minh city and Lam Dong province. Among them, 10 strains were identified as indole-3-acetic acid (IAA)-producing bacteria using the colorimetric method with Salkowski reagent. The highest IAA concentration was recorded at 86.21 ± 1.72 mg/L, produced by strain 1306.5. In addition, the experiment evaluating the effect of IAA-producing bacteria on tissue-cultured Dendrobium sp. plantlets showed that all 10 strains significantly promoted root development within 30 days of observation compared to the untreated control. Among them, strain 1306.5 exhibited the most remarkable effectiveness and was identified as belonging to the genus Pseudomonas, showing the closest relationship to Pseudomonas putida based on molecular identification and biochemical characterization. This opens up a promising direction for applying these bacterial strains as bioagents to support sustainable orchid growth and development, contributing to improved cultivation efficiency and the conservation of valuable plant genetic resources.

INVESTIGATION OF FOAM-MAT DRYING CONDITIONS FOR Spirulina POWDER PRODUCTION

2026-01-06T16:24:00+07:00

This study aimed to develop a foam-mat drying process for producing high-quality Spirulina powder and to evaluate the effects of key processing parameters on the final product. The process consisted of two main stages: Foam formation from a fresh Spirulina slurry and foam-mat drying. The investigated factors included ultrasonic treatment time of the algae slurry (10, 20, 30, 40, 50 minutes), algae-to-solvent ratios (1: 10, 1: 15, 1: 20, 1: 25, 1: 30 w/v), concentrations of the foaming stabilizer carboxymethyl cellulose (CMC) at 0.25, 0.5, 0.75, 1%, whipping times of 1, 3, 5, 7, 9 minutes, foam layer thicknesses of 2, 3, 4, 5, 6 mm, and drying temperatures of 50, 60, 70, 80°C. Optimal foaming conditions were achieved at 30 minutes of ultrasonication, a Spirulina-to-water ratio of 1: 25 (w/v), 0.75% CMC (based on the biomass) and 3 minutes of whipping. In the drying stage, foam layers 3 - 4 mm thick dried at 70 °C required approximately 200 - 220 min and yielded powders with high solids recovery (~ 91%), good solubility, a protein content of about 66.6 g/100 g dry weight and a phycocyanin content of approximately 93.6 mg/g dry weight. Compared with vacuum drying at the same temperature, foam-mat drying markedly shortened the drying time and preserved phycocyanin to a significantly greater extent, while maintaining similar recovery yields. This highlights its potential as a suitable technology for producing Spirulina powders enriched in bioactive compounds. The foam‐mat drying process developed in this study satisfactorily met the research objectives. Optimization of whipping conditions and stabilizer ratios improved drying efficiency while preserving protein content and maintaining the final powder moisture below 5%. The results demonstrate that foam‐mat drying is a suitable method for processing Spirulina, enhancing drying rate, improving powder quality, and providing a foundation for future scale-up.

EVALUATION OF THE ENHANCEMENT IN ANTIBACTERIAL CAPABILITY OF HERBS AGAINST vibrio parahaemolyticus USING OPTIMIZED EXTRACTION PROCESS

2026-01-06T16:27:24+07:00

This study evaluated the antibacterial capability of three optimized herbal extracts against Vibrio parahaemolyticus, including Piper betle, Ocimum basilicum and Centella asiatica. The optimization was carried out on three extracting conditions: i) ethanol concentration (30, 50, 70, 95%); ii) soaking duration (3, 5, 7, 9 days); and iii) ratio of sample (g) & solvent (mL) (1:10, 1:20, 1:30, 1:40). Results identified the optimal procedure as follows: (i) ethanol concentration of 70%, soaking duration of 7 days, 1:30 ratio for Piper betle and Ocimum basilicum, 1:40 ratio forCentella asiatica. The optimized extracts were then compared with the unoptimized ones for zone diameter of inhibition (ZDI), minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), and the bacteriacidal capability on enumeration culture. Optimized extracts improved ZDI against V. parahaemolyticus by 1.5 times (P < 0,05), together with MIC and MBC by 2 times. Moreover, optimized extracts also reduced the bacterial number in enumeration culture by 10 times (P < 0,05) in comparison with the unoptimized ones. Therefore, this study indicated the enhancement in antibacterial capability of the optimized herbal extracts and also highlighted their potential use in V. parahaemolyticus treatment.

ANALYSING FINANCIAL EFICIENEY AND ESTIMATING ENERGY CONSUMPTION OF WHITELEG SHRIMP (litopenaeus vannamei) FARMING MODEL APPLYING THE ASC SHRIMP STANDARD

2026-01-06T16:29:54+07:00

This study was conducted on 39 whiteleg shrimp farming households, encompassing 75 ponds operating under two farming models: Earthen ponds (EPFM) and plastic-lined ponds (PPFM), within a cooperative in Dong Hai district, Bac Lieu province. The research compared financial and energy efficiency between EPFM and PPFM models based on the Aquaculture Stewardship Council standards in 2023. Data collected included production costs, revenues, profits, and energy consumption. Results indicated that PPFM consumed 29,396 ± 10,763 MJ per 1,000 m², equivalent to 6,904 ± 3,433 MJ per ton of shrimp at the farm gate, which was 4.42 and 1.48 times higher, respectively, than EPFM. Feed costs represented the highest proportion of total production costs in both models, accounting for 80.4% in PPFM (301,026,396 ± 118,027,958 VND/1,000 m²/crop) and 82.6% in EPFM (173,025,132 ± 58,520,839 VND/1,000 m²/crop). Although PPFM achieved 1.74 times higher revenue compared to EPFM, financial analysis revealed that EPFM generated higher profit per unit of investment. The differences in energy consumption and cost-efficiency between the two models were statistically significant. These findings offer essential insights for aquaculture investors and policymakers, highlighting the need to balance economic benefits with environmental impacts—particularly energy use—when selecting shrimp farming systems.

EFFECT OF NITROGEN AND PHOSPHORUS CONCENTRATIONS ON THE TREATMENT EFFICIENCY OF BIOGAS EFFLUENT OF GIANT SALVINIA (Salvinia molesta)

2026-01-06T16:33:02+07:00

The study was conducted to determine the potential of giant salvinia (Salvinia molesta) for treating biogas effluent. The experiment was conduted in a nethouse with 6 treatments, which were the dilution ratio of biogas effluent (NT) from pig farms with river water (NS), including of 5% NT + 95% NS (NT1), 10% NT + 90% NS (NT2), 20% NT + 80% NS (NT3), 30% NT + 70% NS (NT4), 40% NT + 60% NS (NT5) and 50% NT + 50% NS (NT6). The treatments were arranged in a completely randomized design with 3 replications. A plant weight of 158 g/tank (equivalent to 158 g for 0.15 m² of treatment area) was applied to treat wastewater with each tank volume of 35 L (25 cm). The hydraulic retention time in the system was set for 15 days and water samples were collected at each every 5 days. After 15 days of operation, the treated water quality parameters including pH, COD and TP were all within the allowable limits according to QCVN 62:2025/BTNMT (column B). The COD removal efficiency of the treatments NT1, NT2, NT3, NT4, NT5, NT6 were 77.2; 72.1; 79.4; 75.6; 82.8; 72.5%, respectively. Similarly, the total inorganic nitrogen (TIN) removal efficiency were 98.1; 98.4; 98.8; 99.0; 99.1; 98.6% and TP was removed with the respective efficiencies of 96.5; 86.6; 98.3; 96.3; 98.1; 90.3%. In which, the NT3, NT4, NT5 treatments simultaneously provided the highest COD, TIN, TP removal efficiency. This shows that the inlet concentrations of about 216.0 - 248.0 mg COD/L, 13.9 - 29.7 mg TIN/L, 5.2 - 8.3 mg TP/L of NT3, NT4, NT5 treatments are optimal for the absorption activity of giant salvinia as well as symbiotic microbial processes, helping the system operate stably and achieve outstanding treatment efficiency. Giant Salvinia fresh weight was increased 2.08 - 2.18 times after 15 days and the dilution ratios did not affect the plant growth. Using giant salvinia for wastewater treatment is an effective, low-cost biological solution, easy to apply for households in the Mekong delta in the VACB model.

ASSESSING THE IMPACT OF SERVICE QUALITY ON CUSTOMER SATISFACTION AT TRA NOC - O MON WATER SUPPLY JOINT STOCK COMPANY, CAN THO CITY

2026-01-06T16:36:25+07:00

This study was conducted to assess the impact of service quality factors on customer satisfaction with water supply services at Tra Noc - O Mon Water Supply Joint Stock Company. Given the company's existing limitations such as high water loss, unstable water pressure, complex procedures, and good customer service but limited professionalism, the study used a SERVQUAL model adjusted to suit the Vietnamese context. The research method combined qualitative and quantitative approaches, surveying 70 households using water supply services. Cronbach's Alpha test, exploratory factor analysis (EFA), and multiple linear regression were performed using XLSTAT software. The results showed that the model fits and explains 51.9% of the variation in satisfaction (adjusted R² = 0.519). Three factors positively impact satisfaction: tangible facilities, reliability and professionalism, and safety. The research results indicate that Tra Noc - O Mon Water Supply Joint Stock Company needs to focus on upgrading infrastructure, increasing professionalism, and ensuring water quality; while simultaneously simplifying processes and improving service attitudes to enhance customer satisfaction and achieve sustainable development in the future.

ASSESSMENT OF PERCEPTIONS AND BEHAVIORS REGARDING THE USE OF RARE FOREST SPECIES IN THE NIGHT AREA OF THANH SA - PHUONG HOANG NATURE RESERVE, THAI NGUYEN PROVINCE

2026-01-06T16:38:45+07:00

This study examines the relationship between socio-economic characteristics and awareness and behavior regarding the use of rare and valuable forest tree species among communities and management staff in the buffer zone of the Than Sa - Phuong Hoang Nature Reserve in Thai Nguyen province. Data were collected from 96 survey questionnaires and processed using SPSS 26.0, employing descriptive statistics, Pearson correlation and multiple linear regression. The results show that education level and occupation are important variables significantly influencing awareness and behavior regarding the use/level of use of rare and valuable forest tree species. Management staff scored higher in awareness and tended to use them more cautiously, while local people had a higher/more frequent harvesting frequency, especially for valuable timber and medicinal plants with economic value. The regression model indicates three significant variables: educational level (β = 0.372), occupation (β = 0.415) and target group (residents/officials) (β = –0.327), with an adjusted R² of 0.41, which represents the variability in awareness and usage behavior. The high level of exploitation of some species poses a risk of genetic resource depletion in the wild. The study proposes integrating communication and education, sustainable livelihood development, and co-management mechanisms between management agencies and local communities in strategies for the conservation and rational use of rare and valuable forest tree species in the buffer zone of the protected area.