Vol. 23 No. 6 (2025): Tạp chí Khoa học Nông nghiệp Việt Nam

Off-season cabbage production means growing cabbage during the summer months in Northern Vietnam. Therefore, this study aimed to select suitable off-season cabbage varieties and off-season planting date to take advantage of the favorable highland climate. A two-factor experiment was arranged in a split-plot design with main plot as three off-season planting date (March 25, 2023 (season 1), April 14, 2023 (season 2), May 7, 2023 (Season 3)), while subplots were three cabbage varieties Grand KKcross, Green Helmet and HMT34 with three replications. The results showed that both seasons 1 and 2 were suitable for the cabbage growth, physiology, yield and quality, with an actual yields of 22.48 tons ha-1 and 21.54 tons ha-1, respectively. Among the tested varieties, Grand KK cross cabbage was the most suitable for off-season cabbage production with the highest average head weight and actual yield (23.06 tons ha-1). The combination of Season 1 or 2 with the Grand KK cross proved the most optimal for the highland commune Van Son, as evidenced by superior growth characteristics, physiological performance, yield, and quality compared to other combinations, achieving actual yields of 26.67 tons ha-1 and 24.57 tons ha-1, respectively.

Dioscorea persimilis Prain et Burkill belongs to the genus Dioscorea and is a plant of significant economic and medicinal value. It is also a specialty of the Huong Pagoda area, closely associated with local culture and traditions. However, the cultivation of D. persimilis in this region remains small-scale and mainly reliant on wild harvesting, highlighting the need for research to develop its genetic resources, establish cultivated medicinal production zones, and create local products for tourism, thereby improving livelihoods. This study evaluated the agronomic traits, nutritional and medicinal quality, and genetic characteristics of D. persimilis in the Huong Pagoda area. The results identified key agro-biological features including stem, leaf, and tuber morphology, tuber weight, actual yield, and various nutritional and medicinal quality indicators. Genetic analysis using PCR and chloroplast gene sequencing revealed high similarity with D. persimilis reference sequences from GenBank and demonstrated close genetic relationships among samples, indicating strong and stable gene flow within the population. These findings contribute to the conservation of valuable genetic resources, support the development of branded specialty products from D. persimilis of Huong Pagoda, and play a role in promoting local economic development and biodiversity conservation.

Cnidoscolus aconitifolius is a high nutritional crop and newly introduced to Vietnam. However, the crop is difficult to propagate by true seeds. The present study was conducted to investigate asexual propagation of Cnidoscolus aconitifolius through cuttings using different concentrations of α-NAA, cutting position and growing medium. Three experiments were arranged in a randomized complete block design (RCBD) with three replications. The results showed that the tip or base cuttings of C. aconitifolius treated with α-NAA at concentration of 1,000ppm for 30 seconds and then plantedon growing medium conaining smoked rice husk : coconut fiber : sand with a ratio of 2:1:1 were optimal. The C. aconitifolius cuttings grew well, had a high rooting rate of 95 to 97%, large number of adventitious roots (15.17 roots/cutting), longest root length (6.62cm), largest shoot length (8.6 shoots/cutting) and an average leaf number of 9.76 leaves/cutting; green shoot leaves and SPAD, Fv/Fm index of leaves reached the highest values ​​of 40.21 and 0.87, respectively.

This study aimed to evaluate beneficial bacterial strains with the potential for environmental water treatment and resistance to the bacterium Flavobacterium columnare, which poses a threat to various species of freshwater fish. A total of 11 strains of Bacillus sp. and 8 strains of Lactobacillus sp. were successfully isolated from 15 sediment samples from cultured shrimp, fish and natural lakes. Assessment of the protein, cellulose, and starch degradation capabilities of Bacillus strains, along with the calcium carbonate dissolution activity of Lactobacillus strains, indicated that 4 out of the 19 strains exhibited significant degradation potential. Identification of these 4 strains through 16S rRNA sequencing revealed 2 strains of Bacillus subtilis, 1 strain of Bacillus amyloliquefaciens, and 1 strain of Lactobacillus plantarum. The evaluation of the antagonistic effects of these strains against 6 F. columnare strains isolated from freshwater fish demonstrated inhibition zone diameters ranging from 9.9 to 11.5 mm for B. subtilis, 13.1 to 14.9mm for B. amyloliquefaciens, and 24.8 to 28.4mm for L. plantarum. The results highlight the potential of these four isolated microbial strains for developing formulations aimed at environmental remediation and prevention disease related to F. columnare in freshwater aquaculture.

This study aimed to assess the composition and biodiversity of microalgae in freshwater fish ponds in Hong Duc Commune, Ninh Giang District, Hai Duong Province. Microalgal composition and density were analyzed in eight freshwater fish ponds, including five grow-out polyculture ponds, one co-cultured tilapia and grass carp fingerlings pond, one tilapia fingerling pond, and one red tilapia pond. Biodiversity indices including species diversity index (H’), dominance index (D) and Wilson-Shmida biodiversity were calculated for all ponds. A total of 173 microalgal species were identified with the following share: Chlorophyta 37%, Euglenophyta and Cyanobacteria each approximately 20-21%, Heterokontophyta 14%, Charophyta 6%, and Dinoflagellata 1%. A total of 10 classes, 23 orders, 35 families, and 57 genera belonging to six phyla were recorded in the studied ponds. The number of microalgal species per pond ranged from 72 to 92. The species diversity index (H’) varied between 2.6 and 4.2, with higher values observed in fingerling ponds compared to grow-out fish ponds. The dominance index (D) values in the ponds ranged from 0.02 to 0.22, suggesting the absence of any dominant phytoplankton species in these systems. Additionally, no significant differences were observed in the Wilson-Shmida biodiversity index among the ponds. The microalgal density in the sampled ponds ranged from 1 × 10⁵ to 4.5 × 10⁵ cells/ml.

Medicinal plants are increasingly being researched and widely utilized in aquaculture; however, certain herbs also possess inherent toxicity. The current study assessed the toxicity of extracts from Gnetum montanum and determined the concentration or dose causing 50% mortality (LC50/LD50) in striped catfish through immersion and oral administration. Striped catfish fingerlings (~10 g) were exposed to water containing various extract concentrations (800; 1,000; 1,200; 1,400, and 1,600 mg/l), while the oral gavage method involved doses of 350, 450, 550, 650, and 750 mg/kg fish. Mortality rates were observed at 24, 48, 72, and 96 hours. The results showed that Gam extract was toxic to striped catfish fingerlings. The LC50 after 24, 48, and 72/96h were 1,114.81; 1,100.56; and 1,046.62 mg/l, respectively; the LD50 was 562.83 mg/kg fish after 48h and 518.23 mg/kg fish after 72/96h. Safe concentrations were below 111.48, 110.06, and 104.66 mg/l after 24, 48, and 72/96h, respectively; safe doses were below 56.28 mg/kg fish after 48h and 51.82 mg/kg fish after 72/96h. Fish exhibiting signs of toxicity showed pronounced alterations in the morphology and coloration of internal organs such as the gallbladder, liver, spleen, kidney, and heart. Observed changes included congestion, discoloration, and deformation, indicating significant physiological impacts of the toxic compounds on internal organ function.

The study was conducted to evaluate hematological parameters, persistence of antibodies against African swine fever virus (ASFV), and growth performance of D × DLY crossbred pigs, from Duroc boars and Duroc × (Landrace × Yorkshire) survivor sows infected by ASFV. Ear tattoos and ear tags were applied to the piglets at birth and weaning, respectively. At 2, 3, 4, 5, 6, and 7 months of age, body weight of each animal was recorded, and blood samples were collected for hematological and immunological analyses. The results showed that antibody levels remained positively throughout the study period (from 2 to 7 months of age). Red blood cell counts ranged from 6.07 to 7.82 T/L, hemoglobin levels from 9.77 to 11.26 g/dL, platelet counts from 284.71 to 344.70 G/L, and white blood cell counts from 17.43 to 23.78 G/L. Most hematological parameters in pigs born from ASFV survivor sows were within the normal range, though they tended on the lower range of the reference intervals. Body weights at 2, 3, 4, 5, 6, and 7 months of age were 13.5, 30.88, 43.86, 65.33, 81.94, and 99.33 kg, respectively. The growth performance of D × DLY crossbred pigs was lower than normal animals.

Monkey head mushroom (Hericium erinaceus) is a medicinal mushroom with high therapeutic value; however, research on its cultivation and processing in Vietnam remains limited compared to other mushrooms such as lingzhi or wood ear mushroom. This study aimed to evaluate the effects of cultivation substrates and drying conditions on the yield and quality, respectively, of H. erinaceus. The results demonstrated that substrate composition significantly influenced mycelial growth and fruiting body formation. Notably, strain He-2 did not form fruiting body primordia on substrates lacking sawdust. The substrate formulation containing 89% sawdust, 10% rice bran, and 1% CaCO3 yielded the highest biological efficiency (51.80%), followed by the formulation with 20% cotton waste, 69% sawdust, 10% rice bran, and 1% CaCO3 (51.28%). Regarding drying conditions, the suitable condition was identified as drying at 35°C with 75% ventilation for the first 12 hours and 25% thereafter, which effectively preserved polysaccharide content and total amino acids. These findings contribute to the development of an improved cultivation and processing strategy for enhancing both productivity and medicinal quality of H. erinaceus

Night-time economy contributes significantly to the economic development of Hoan Kiem district, Hanoi city. The district government has focused on developing this type of economy by planning, diversifying types, increasing operating hours and optimizing the use of night-time economic infrastructure. However, the process of exploiting this type of economy still has many shortcomings and limitations. Based on the results of a survey of 120 consumers and 72 enterprises, combined with the application of descriptive statistics and comparative statistics, the study analyzed the current situation of solutions for night-time economic development and factors affecting night-time economic development in Hoan Kiem district, Hanoi city. Solutions to promote the night-time economy such as improving service quality, improving traffic infrastructure and promoting product promotion activities have been mentioned in the study.

The article focuses on discussing several theoretical issues related to public investment in agricultural infrastructure development. The study adopts a descriptive overview analysis method, integrating content and thematic analysis of 57 academic sources, to clarify the conceptual dimensions of public investment in agricultural infrastructure development. The literature review indicates that public investment in agricultural infrastructure has a positive impact on labor productivity, reduces production costs, enhances competitiveness, and generates spillover effects that attract private investment. The study reveals that the scope of public investment in agricultural infrastructure encompasses processes ranging from needs assessment, capital allocation and budgeting, procurement and contractor selection, project implementation, acceptance and commissioning, operation and maintenance, to monitoring, evaluation, and assessment of investment outcomes and effectiveness. Furthermore, the review highlights that policy mechanisms, the capacity of personnel and contractors, financial resources and local funding mobilization methods, as well as the nature of the projects themselves, are key factors influencing public investment in agricultural infrastructure development.

The article applies narrative review method, particularly synthesizing data and information from scientific articles, research reports, official websites and related documents with the aims of: (i) Making an overview of the experiences of some countries and regions in the world in developing multifunctional agriculture and (ii) Drawing some lessons for promoting the development of multifunctional agriculture in Vietnam in the current context. The overall research results indicate that the development of multifunctional agriculture in most countries in the world contributes to exploiting the multifaceted values ​​of agriculture, not only limited to providing food but also creating ecosystem services, conserving natural resources, and contributing to rural socio-economic development.

Ecotourism development plays an important role in the socio-economic development of Vietnam. The article, therefore, aims to systematize some theoretical issues and basic viewpoints on ecotourism development. From there, some suggested research contents on ecotourism development are: developing ecotourism markets and products; developing technical facilities in tourism; developing ecotourism routes; developing human resources; enhancing brand promotion; especially environmental protection and climate change response in ecotourism development. Some factors affecting ecotourism development are also pointed out such as: tourism development policy mechanisms; tourism development planning; tourism resources; social awareness and participation of local communities in tourism; tourism infrastructure; linking tourism development between localities; local socio-economic development; digital technology and international integration.

Rice (Oryza sativa L.) is an important crop, providing staple food for more than half of the world's population. However, conventional irrigated rice cultivation consumes large amounts of irrigation water and contributes significantly to greenhouse gas emissions, especially methane (CH4). In view of the impact of climate change and the goal of reducing global greenhouse gas emissions, the research and application of water-saving irrigation methods for rice are becoming increasingly important. This paper presents the mechanism of CH4 emissions in rice fields and the benefits of alternate wetting and drying (AWD) to promote the application of this technology in sustainable rice cultivation. The results show that AWD reduces water consumption and irrigation costs, while this technology stimulates rice plant growth, grain yield and quality, improves soil biological activity, and reduces pest infestation and pesticide use. In addition, AWD significantly reduces CH4 emissions in rice fields, which can be converted into carbon credits, potentially increasing farmers' income. Therefore, the adoption of AWD in rice cultivation can play a crucial role in achieving global climate goals, ensuring food security and promoting sustainable agricultural practises.