Vietnam Journal of Agricultural Sciences

This study aimed to evaluate the effects of mulching methods (straw, plastic) and shading (25%, 50%) on the growth and yield of cultivar VT- ĐL2.1 of (Polyscias fruticosa (L.) Harms in Hanoi. The experiment was arranged in a randomized complete block design with three replications from 2020 to 2023. Observed parameters included plant height, number of branches, stem diameter, leaf number, SPAD index, dry matter accumulation, and medicinal material yield. The results showed that straw mulching significantly enhanced plant growth and root productivity. After three years, root yield reached 6.3 tons/ha, higher than by nilon mulching (5.2 tons/ha) and no mulching (5.7 tons/ha). Shading at 25% in the first year of planting was most suitable in terms of dry matter accumulation and 3 years after planting, the root dry weight and medicinal material yield obtained were 301.8 g/plant and 6.4 tons/ha, respectively.

The study aimed to complete an in vitro propagation protocol for Hippeastrum equestre (Aiton) Herb. The in vitro propagation experiments were carried out on MS media containing 30 g/l sucrose, 6 g/l agar, 0.5 g/l active charcoal with different concentrations of 6-Benzylaminopurine (BA), 2,4-dichlorophenoxyacetic (2,4-D), α-Napthaleneacetic Acid (α-NAA), and Indole-3-Acetic Acid (IAA). The results showed that plant material treated with Presept at 5 g/l for 50 minutes achieved the highest survival rate (90%). Shooting medium supplemented with 3 mg/l BA and 1.0 mg/l 2,4-D gained the highest shooting ability. Rooting medium supplemented with 1 mg/l α-NAA or 1.5 mg/l IAA was optimal for the highest rooting ability, with a rooting rate of 100% and number of roots/explant ranging from 3.33 to 4.00. In the nursery, coir : soil : organic fertilizer substrate with a ratio of 6:3:1 (v/v) yielded the highest survival rate (100%), leaf number (3.53 leaves/plant), and plant height (16.34 cm). The result could be utilized for large-scale propagation of Hippeastrum in Vietnam.

Amblyseius largoensis is a polyphagous predatory mite commonly found on citrus crops in northern Vietnam. This study evaluated its feeding capacity on the eggs, I mmature stages, and adult females of four prey mite species: Schizotetranychus hindustanicus, Tetranychus cinnabarinus, Panonychus citri, and Carpoglyphus lactis. Laboratory assays were conducted under two conditions: no-choice and choice tests. In the no-choice assays, A. largoensis consumed the highest number of C. lactis eggs, followed by T. cinnabarinus, whereas S. hindustanicus eggs were consumed the least. Conversely, the immature stages and adult females of S. hindustanicus were preyed upon in the greatest numbers. In the choice assays based on developmental stages of each prey species, A. largoensis preferentially consumed the eggs of P. citri, T. cinnabarinus, and C. lactis. For S. hindustanicus, the immature stage was the most heavily consumed. When prey species were offered simultaneously within the same developmental stage, C. lactis eggs showed the highest selection rate, while the immature and adult female stages of S. hindustanicus exhibited the highest selection rates among their respective categories. Overall, the results highlight the strong potential of A. largoensis as a biological control agent against pest mites on citrus. The findings also suggest that C. lactis could serve as an effective alternative prey for mass-rearing this predatory mite at a commercial scale.

This study was conducted to determine the biological characteristics, growth pattern, and mortality parameters of the southern rough shrimp Trachysalambria longipes (Paulson, 1875) in the coastal waters of Quang Ngai, serving as a basis for sustainable stock assessment and management. A total of 1,421 individuals were collected monthly from trawl catches between April 2021 and September 2022. Body length, body weight, and sex were recorded to analyze the length-weight relationship, estimate the von Bertalanffy Growth Function (VBGF), and determine mortality parameters. The length-weight regression for the population was W = 0.3535 × 10⁻⁴ × BL²·⁸¹ (R² = 0.90), indicating a negative allometric growth pattern, with body length increasing faster than weight. The VBGF growth parameters were BL∞ = 115mm, K = 1.4 year⁻¹, and Φ′ = 2.27. Females matured at 74 mm body length, spawned year-round with peaks in June and September, and dominated the population (male:female ratio 0.39:1.00). Estimated mortality parameters were M = 2.96 year⁻¹, F = 2.64 year⁻¹, and Z = 5.60 year⁻¹, with an exploitation rate E = 0.47 close to the optimum level (0.5), indicating a moderate fishing pressure and that the population has not yet been overexploited.

This study evaluated the antibacterial activity of essential oil from Vietnamese balm (Elsholtzia ciliata) against three pathogenic bacteria in freshwater cultured fish: Aeromonas hydrophila (Att1), Edwardsiella ictaluri (Ecd20), and Streptococcus agalactiae (Svb2). The essential oil was extracted using microwave-assisted steam distillation and its chemical composition was analyzed by GC-MS. Experiments with microwave treatment times of 2-8 minutes, 500W power, and oil concentrations of 5-15% showed that antibacterial efficacy increased with both concentration and treatment duration. Ecd20 was the most sensitive strain (31.7mm inhibition zone at 15% after 8 minutes), followed by Att1 (18mm), while Svb2 was less sensitive but still showed significant inhibition. The MIC values for Ecd20, Svb2, and Att1 were 0.39, 0.78, and 1.56 mg/ml, respectively. Chemical analysis identified Linoleic acid (26.64%), Oleic acid (16.97%), Citral (10.9%), beta-cis-Ocimene (7.38%), and beta-Caryophyllene (7.56%) as major constituents likely contributing to the bioactivity. The results confirmed that microwave treatment enhances the antibacterial effect, particularly evident at 8 minutes. This study provides scientific evidence linking chemical composition and biological activity, and suggests the potential application of E. ciliata essential oil as a natural alternative to antibiotics in aquaculture.

This study aimed to isolate and screen indigenous Bacillus strains capable of heterotrophic nitrification and aerobic denitrification from shrimp sediments. In this study, 17 out of 53 isolates were selected based on aerobic denitrification ability in BTB and DM1 media. Notably, the strain PT1.4 exhibited an outstanding efficiency of nitrogen removal (92.5%). Morphological and biochemical features of this strain were consistent with the genus Bacillus and the 16S rRNA gene sequencing revealed 99.6% similarity to Bacillus cereus. For aerobic denitrification, strain PT1.4 achieved removal efficiencies of 95.2% for N-NO2- concentration and 98.3% for N-NO3- concentration within 120 hours of incubation, whereas under heterotrophic nitrification, over 91.3% of N-NH4+ concentration was eliminated after 72 hours of cultivation. In contrast to the increasing OD600 values, the concentrations of organic matter (CODMn) decreased in parallel with the decreasing concentrations of the inorganic N sources. These findings indicate that strain PT1.4 is capable of removing both nitrogen sources and organic compounds via assimilation and heterotrophic nitrification - aerobic denitrification pathways. Hence, strain PT1.4 is considered as a promising probiotic candidate for enhancing water quality in intensive shrimp practices.

Probiotics are one of the most popular alternatives to antibiotics for disease prevention and growth promotion in livestock. Bacillus amyloliquefaciens (B. amyloliquefaciens) possesses several characteristics suitable for probiotics, including resistance to high temperatures, low pH, bile salts, and antagonism against pathogens. This study was conducted to isolate and select B. amyloliquefaciens strains antagonistic against Salmonella gallinarum (S. gallinarum), which causes Salmonellosis. The result showed that four B. amyloliquefaciens strains were isolated and identified from 100 fresh fecal samples of healthy chickens using the culture methods and Matrix-Assisted Laser Desorption/Ionization - Time-of-Flight (MALDI-TOF) technology. The isolates were not hemolytic on blood agar and exhibited high stability in adverse conditions (pH 3.0 and 0.3% bile salt), with a survival rate greater than 80%. The results of the antimicrobial susceptibility test revealed that all 4/4 (100%) of the B. amyloliquefaciens isolates were resistant to tetracycline and 3/4 (75%) were resistant to erythromycin. The isolates also exhibited strong antagonism against S. gallinarum in vitro, producing inhibition zones with diameters greater > 16 mm.

This study aimed to analyze consumer preferences and the factors influencing the purchase intention of fresh cherry tomatoes in Thai Binh city. Based on a survey of 100 consumers, logistic regression analysis was applied. The results indicate that knowledge about the health benefits of cherry tomatoes was still limited. Consumers preferred cherry tomatoes that are red in color (61.4%), round in shape (68.2%), and mildly sweet in taste (67.0%). Household income and expenditure on food were positively associated with purchase intention (β = 0.275; P <0.05 and β = 1.734; P <0.01). In addition, attention to freshness, safety, and traceability of origin also exerted a positive influence. Notably, general knowledge and knowledge about health benefits played a crucial role in promoting purchasing behavior (β = 1.345; P <0.1 and β = 0.685; P <0.05). Based on these findings, the study proposes policy recommendations on strengthening communication strategies, enhancing product quality, and expanding distribution channels that align with consumer preferences and behaviors.

Based on an overview of theoretical and practical issues, the article contributed to explaining and developing the theoretical basis for clothing disposal behavior in the context of practical issues in the world and in Vietnam. The article had synthesized and developed five ways of clothing disposal, including: direct reuse, indirect reuse, storage, collection point for recycling, and disposal as household waste. Based on the characteristics of the apparel products, the characteristics of the individual owning the products and other reasons, consumers can consider choosing among the five above options, so that their used clothing disposal behavior might be more meaningful. The extended of the theory of planned behavior model was used to develop a theoretical model of the clothing disposal behavior.

During the 2021-2025 period, the National Target Programs played a pivotal role in promoting socio-economic development, particularly in disadvantaged and remote areas of Vietnam. By concentrating financial, technical, and human resources, these Programs not only upgraded infrastructure, developed production and basic services, but also improved livelihoods, enhanced living standards, contributed to poverty reduction, and narrowing development gaps across regions. However, their implementation also revealed certain limitations and shortcomings, necessitating a comprehensive review and evaluation to guide the 2026-2030 period. Accordingly, this paper aimed to clarify the theoretical issues, synthesize and analyze international experiences in mainstreaming National Target Programs, identify achievements as well as challenges encountered during the 2021-2025 implementation phase, and propose solutions to enhance the effectiveness of program mainstreaming in the 2026-2030 period.

Aquaculture is the fastest-growing sector worldwide, contributing significant quantities to the supply of food for human consumption and have surpassed wild-capture amounts. The expansion and intensification of aquaculture models from inland to mariculture cause eutrophication, which is often accompanied by algal blooms because of aquatic nutrient loadings (mainly N:P ratio). Harmful algal blooms (HABs) are typically phytoplankton species including Chaetoceros spp., Heterosigma spp., Microcystis spp., Karenia spp., Alexandrium spp., Pyrodinium sp., Noctiluca sp., Dinophys sp., Trichodesmium sp., Prorocentrum sp., Pseudonitzhia sp., and Cochlodinium sp., that produce no or few toxins harmful to wild and farmed fish, shrimp, shellfish, and even humans, causing severe illnesses referred to as paralytic, diarrheic, and amnesic shellfish poisoning in humans who use them. This paper discusses the occurrence of HABs, the factors that generate and maintain HABs, and the negative impacts of HABs on aquaculture in the past, present, and future with the aim of improving the assessment of food poisoning risks to consumers.

This article provided an overview of ecological efficiency in livestock farming. It focused on the following contents: The concept of ecological efficiency; methods for evaluating ecological efficiency and research prospects on ecological efficiency in livestock farming in Vietnam. The results show that ecological efficiency assessment is very important in sustainable development and has received attention and research from the world. Although Vietnam has oriented towards sustainable livestock farming development, there is currently no specific research on ecological efficiency in livestock farming. This is a promising research direction in the coming time in Vietnam and is very necessary for the government to assess the level of sustainable development and make the right decisions on livestock farming development.

The development of macadamia cultivation has emerged as one of the key strategic orientations to diversify cropping systems and enhance economic value, particularly in the Northwest region of Vietnam. From the perspective of “developing agricultural commodity production,” this study systematized the theoretical foundations of macadamia production development, with core dimensions including: planning of production area, selection of suitable varieties, application of advanced technologies, strengthening linkages and cooperation, as well as improving outputs and economic efficiency. The paper further emphasized the significant influence of institutional and policy frameworks, natural conditions, infrastructure, production capacity, and market factors on the expansion of macadamia production. However, a number of barriers remain, such as inconsistent planning, shortage of high-quality varieties, weak technical infrastructure, limited organizational capacity, and unstable consumption markets, which pose considerable challenges to sustainable development. On this basis, the paper proposed several policy implications for Điện Biên province - a locality with substantial potential for macadamia cultivation-in order to gradually establish specialized production zones, organize production in accordance with value chains, and build a stable and sustainable macadamia brand.