Vol 2 No 3 (2019): Vietnam Journal of Agricultural Sciences

Issue Information:

Starting in 2018, VJAS is set to launch a full English version of VJAS and publish quarterly both online and in print with the ISSN 2588-1299. Each issue will contain 5-10 articles, with each article being approximately 5000-8000 words. All submissions will be independently refereed by editorial board members and will undergo rigorous peer-review following international standards from at least two assigned peer reviewers (including one Vietnamese reviewer and one foreign reviewer) who come from universities and research institutes in Vietnam and other countries around the world. The aim of VJAS is to be indexed in ISI/Scopus lists within four to six years from its first published issue (September 2018).

The English version of VJAS is devoted to publishing papers, both scientific articles and reviews or mini-reviews, from all areas related to agriculture disciplines, especially those focusing on crop science, plant protection, animal science, veterinary medicine, aquaculture, agricultural mechanical and electrical engineering, soil science and plant nutrition, ecology and environment, biotechnology, food technology, economics and rural development, and information technology in agriculture, etc.

DOI: https://doi.org/10.31817/vjas.2019.2.3

Published: 2019-12-24

ANIMAL SCIENCE – VETERINARY MEDICINE – AQUACULTURE

The Effects of Short Freshwater Bath Treatments on the Susceptibility to Different Stages of Neobenedenia girellae Infecting Barramundi (Lates calcarifer)

Freshwater treatment for Neobenedenia girellae

by Truong Dinh Hoai, Trinh Thi Trang, Nguyen Thi Huong Giang
https://doi.org/10.31817/vjas.2019.2.3.01
Received: Jun 9, 2019 / Published: Dec 24, 2019
Abstract: Neobenedenia girellae is one of the most pathogenic parasites affecting marine fish in captivity conditions. The use of chemicals for parasite prevention and treatment have several benefits; however, they can cause various negative side-effects. In an effort to discover cost-effective and sustainable practices, our current study was aimed at investigating the efficiency of freshwater treatments on N. girellae. A challenge test was conducted to produce infected fish which became materials for
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the freshwater immersion experiments. The duration and reaction of the parasites at different development stages from eggs to adult parasites were examined. Our findings revealed that 100% of the adults and oncomiracidia of N. girellae were killed quickly in freshwater. The eggs of N. girellae, however, were highly resistant to freshwater with a hatching success rate of more than 95% in all the freshwater immersion treatments (2, 5, 10 and 30min). The eggs hatched mainly on day 7 and finished hatching on day 8. Thus, the freshwater immersion method can be applied to treat N. girellae at most stages excepted for the egg stage. The best practical treatment for this parasite is to perform a replicated immersion recommended 8 days following the first treatment.
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NATURAL RESOURCES AND ENVIRONMENT

Modeling of Infiltration Characteristics by the Modified Kostiakov Method: A Case Study in Thuong River Alluvial Soil in Vietnam

Modeling of Infiltration Characteristics by the Modified Kostiakov Method: A Case Study in Vietnam

by Nguyen Thi Giang, Ngo Thi Dung, Nguyen Van Dung
https://doi.org/10.31817/vjas.2019.2.3.02
Received: Apr 10, 2019 / Published: Dec 24, 2019
Abstract: The purpose of this study was to apply the modified Kostiakov method to determine the soil infiltration rate and permeated water amount of Thuong River alluvial soil for orange plantations in Lang Giang district, Bac Giang province, Vietnam. The soil particle size ranged from 0.02 to 2.00mm mainly found in the surface horizon (>77.7%). The soil was slightly acidic in the surface horizon, and highly acidic in the subsurface horizons (pHKCl from 3.42 to 4.79). The organic matter
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content of the surface horizon was mederate, while it was very low in the other horizons. The total nitrogen (N) content was low (0.15%) in the surface horizon and very low in the subsurface horizons (0.02-0.06%) while the available N was medium. The total phosphorus (P) content in the surface horizon was high (0.4%) and medium in the other horizons. Available P in the surface horizon was high (18.6mg per 100g soil) and decreased in lower depths to only 0.3mg per 100g soil in the deepest (5th) horizon. The total and available potassium measurements were very low. A filtration characteristic model was developed by using the modified Kostiakov method for alluvial soil. The constant values a, a, and b of the equation y = ata + b were 0.8035, 0.758, and 0.00346, respectively, which were smaller than 1. The average percentage difference between the actual and calculated values by the model was only 0.141%, indicating that the calculated values can accurately predict the actual data measurements in the field. 
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ENGINEERING AND TECHNOLOGY

Evaluation of the Physicochemical Properties and Sensory Attributes of Yoghurt Made from Mixtures of Goat’s and Cow’s Milks

Evaluation of the Physicochemical Properties and Sensory Attributes of Yoghurt Made

by Nguyen Duc Doan
https://doi.org/10.31817/vjas.2019.2.3.03
Received: Mar 6, 2019 / Published: Dec 24, 2019
Abstract: The objective of the study was to evaluate the effect of cow’s milk added to goat’s milk on physicochemical properties and sensory attributes of yoghurt. Yoghurts prepared from five different proportions of cow’s milk and goat’s milk were stored at 4-6ºC for 1, 7, and 14 days and then evaluated for their physicochemical (total solids, protein, pH, and acidity) and physical properties (viscosity and water holding capacity), and sensory characteristics (acceptability). The total solids
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of the evaluated yoghurts significantly increased, but the protein content decreased when the amount of cow’s milk increased in the mixtures of milk. The results showed that the pH value of the yoghurt made from only goat’s milk was higher, while the titratable acidity was lower than those of the yoghurts made from the mixtures of goat’s and cow’s milks. The yoghurt obtained from the mixture of milks containing 80% goat’s milk and 20% cow’s milk exhibited the highest viscosity and water holding capacity among the evaluated yoghurts. All the yoghurts received similar scores for color, odor, and texture after all periods of storage, while the highest score in terms of flavor was received for the yoghurt made from the mixture of milks containing 60% goat’s milk and 40% cow’s milk. Addition of cow’s milk to goat’s milk was shown to significantly contribute to the viscosity, water holding capacity, and flavor of the resulting yoghurts.
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REVIEW

The Framework of Ecosystem Services for Economic Valuation Purposes: A Review

The Framework of Ecosystem Services for Economic Valuation Purposes: A Review

by Nguyen Minh Duc
https://doi.org/10.31817/vjas.2019.2.3.04
Received: Dec 25, 2018 / Published: Dec 24, 2019
Abstract: Although humans need ecosystems and ecosystem services for their survival and well-being, most of the global ecosystems and the services that they provide have declined and/or degraded rapidly over the past few decades. In order to find the ways to sustainably use natural resources, substantial efforts have been made to measure and value the ecosystem services. The term ‘ecosystem service’ was interpreted in different ways in the literature. For making correct decisions in natural resource
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management, a consistent way of defining and classifying ecosystem services is needed for valuation purposes. This paper argued for the need to divide ecosystem services into intermediate and final services.
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