Vol. 16 No. 1 (2018)

The present study determined the nitrate contents in vegetables from 31 main vegetable growing localities in Bac Ninh province in the period2015-2016. Vegetable samples were collected in the fields and the nitrate contents were determinated according to Vietnam Standard TCVN 9016:2011 (Vietnam Ministry of Sciences and Technology, 2011). In comparison with the regulations promulgated by the decisions 46/2007/QĐ-BYT and 99/2008/QĐ-BNN, 29 greens mustard samples, 16 cabbage samples, 15 water spinach samples, 7 tomato samples, 9 kohlrabi samples, 2 lettuce samples, 9 coriander samples, and 15 green onion samples contained the nitrate content exceeding the standard, ranging from 1.06 to 12.21 folds, except wax gourd... These results indicate warning to farmers and policy makers of Bac Ninh province to take measures for controling nitrate-content in vegetables.

The current situation of food hygiene and safety in fresh pork as well as the causes of microbial contamination at 31 traditional markets in three representative districts of Lam Dong Province (Bao Loc city, Lam Ha and Duc Trong districts)were investigatedthrough interviewingbutchersand sample tests. The resultsshowed that the contamination rate by E. coliin pork was found at 11.11% and 66.67% at the centralized and residential markets, respectively. The contaminationrate of Salmonellain pork collectedfrom residential marketswas 27.27%whileno Salmonellawas found in the samples fromthe centralized market. Coliformscontamination in water was found at 77.27% and 81.48% with both types of markets, respectively. Tools (knives and cutting boards) usedin the butcher shop didnot meet the requirements forsanitation in terms oftotal aerobic bacteria and Enterobacteriaceaein both types of markets. However, the residues of chloramphenicol, tylosin, tetracycline, clenbuterol, and salbutamol were not found in the pork sold at both types of markets.

The present study was conducted to evaluate the extirpation effect of plant - derived Pyrethroid compound on dog and cattleticks. Boophilus microplusand Rhipicephalus sanguineusat different stages were immersed into Pyrethroid compound at different concentrations: 1, 3, 5, 6, 7, 8, 9, and 10%. The mortality rates of ticks were recorded after 24 hours and 48 hours treatment. The highest mortality rate ofBoophilus micropluswas 63.3% after 24 hours and reached to 70% after 48 hours when treated with Pyrethroid compound at 10%. At 1%, Pyrethroid compound did not show any extirpation effect after 24 hours, only 3,33 % dog sticks and 10 % cattle sticks were killed after 48 hours. All Boophilus microplus andRhipicephalus sanguineusat larva and nymph stages were extirpated by Perythroid compound regardless its concentration. To evaluate the extirpation effect of Perythroid compound on ticks parasited on cattle, 5% Perythroid compound solution was used as spray treatment. 100% Boophilus microplus andRhipicephalus sanguineuat larva and nymph stages were extirpated; 84.85% and 91.70% adult ticks were killed after 24 and 48 hours,respectively.

To develop immunochromatographic strips for direct detection of the Streptococcus suistype 2 (S. suis2) antigen,1,5x108CFU of inactivated S. suis2 mixed well with Freund’s adjuvant was injected to Swiss albino mice to produce polyclonal antibodies. Then, the S. suis 2 polyclonal antibody (360 µg/ml) was mixed with gold colloid solution (pH 8.0) to create colloidal gold probe. Results indicated that the optimal concentration of capture antibodies in test lane was 2 mg/ml. The Kit had high sensitivity and specificity and no cross-reaction with E. coli ATCC,P. aeruginosaATCC, S. aureus ATCCor other strains ofS. suis. The detection sensitivity was found to be as high as 5x105CFU. In conclusion, the Kit is easy for the use and highlyefficient forS. Suistype 2 detection.

This paper reported the results of investigation on the prevalence of CIAV in Hanoi and its vicinity. By PCR method, the virus was detected in 92.86% of sampling farms and 50.81% of tested samples. The analyses of capsid protein coding gene revealed two genetic groups (group 2 and 3) of CIAV circulating in investigated areas. It was also demonstrated that all field strains of CIAV differed from the vaccine strains (Cux-1, P4 and 3711).

The study aimed at investigating the effect of lime (CaO) application on the change ofsoil exchangeable calium and sodium and yields of 3 rice varieties in salineacid sulphatesoil at Long My district, Hau Giang province. The field experiment was arranged in 3x2 factorial designs: three rice varieties and two lime rates. Results showed that the application of CaO increased soil exchangeable Caandsoil EC buty reducedsoil exchangeable Na in the 0-20cm soil layer. Thissoil improvement brought about highergrain yield through increasedpanicle number/m2 and grain number/panicle. Under soilsalinitycondition at early crop season, grain yield of OM 5451 and OM 8017 washigher than that of OM 4900. The trial result showed damage from salinityinstrusion during wet season 2017 has been reducedandprofit obtained from the trial was higher than that of farmer practicewith VnD3,158,000 per ha. It is recommended to use OM 5451 or OM 8017 varieties and applyimg CaO at 1.0 t/ha for salt-affectedsoils inLong My,Hau Giang.

A study was conducted to analyze the current status of agricultural land utilization and find solutions for restructuring the agricultural sector in terms of agricultural land use change in Nam Sach District, Hai Duong Province. Secondary and primary data collection were collectedin the study. Multi-objective optimization model was used to determine the area of 31 actual land utilization types serving as basis for change in the land use towards higher value added. At present, there were 8 land use types (LUTs) and 31 land utilization types, in which the area of two rice crops was largest with 2,480.71 ha, accounting for 34.65% of the total agricultural land. Based on the results of multi-objective optimization model analysis, the evaluation of efficiency of current land use and agricultural development orientations of the district, the areas under two rice crops (1,180.71 ha), aquaculture (505.19 ha), and rice -non-rice crops (52.75 ha) are recommended to change to two rice - non-rice crops, integrated farms, and fruit production, respectively.

The aim of this study was to assess sustainable livelihood development of forest-dependent people in the highland areas of Bac Can province. Data were collected through direct interviews of265 households living near forests in the districts of Ba Be and Na Ri. Descriptive statistics, comparisonsusing student T-test, Chi-square and Likert scale were used. Results revealed ahigh degree of the househods’ forest-dependence, limited income and medium sustainable livelihood development. High level of forest dependence was evidenced withthe fact that the higher forest-dependent strategy the lower level of sustainable development of livelihood. To enforce the policy of sustainable livelihood development, the government should adopt measures to reduce reliance on the forest, improve income for the households, and maintain social relationships and ecological environment.

The study was conducted to analyze the level of market participation of Ho chicken farming households in Thuan Thanh district, Bac Ninh province. Censored regression model (Tobit model) was used to evaluate the factors affecting market participationlevelof 68 Ho chicken farminghouseholds. Results indicatedthat the subsistencehouseholds accounted for thehighest involvement percentage with 39.7%,followed by commercial households and transitionhouseholds with 35.3% and 25%,respectively. Experience of household head, family labor, farm size, Ho chickenherd sizeand households’ accesstoextension service hada positive influence on the level of market participation of the households whilethe age of household head and percentage of average annual non- farm income showeda negative influence on the level of market participation of the households.

Sustainable development of raw tea plays an important role in the economic development of Phu Tho province. The results of the survey conducted on 203 tea farmers and some raw teamanufacturing enterprises showed that safe tea production was not infull compliance with the regulations. Based on the analysis of the situation, the sustainability assessment as well as the analysis of the influencing factors,some major solutions for sustainable tea production in Phu Tho province next timewere proposed.