Vol. 15 No. 6 (2017)

The aim of this study was to determine the effect of exogenous application of salicylic acid (SA 0.25 mM) and calcium nitrate (Ca(NO3)250 mM), singly or in combination, on plant growth, photosynthetic capacity, and some stress markers of yardlong bean plants exposed to salt stress (0.3% NaCl). Application of 0.3% NaCl reduced plant growth, total chlorophylland carotenoid content, and chlorophyll fluorescent (Fv/Fm). Exogenous application of SA or Ca2+alone alleviated the level of proline content, saturation of water shortage, hydrogen peroxide (H2O2), ion leakeageandmalondialdehyde (MDA) in the presence of NaCl. Nevertheless, the best results in growth of stemsand leaves, photosynthetic pigment concentrations, and some stress markers were observedin response to the combined SA + Ca2+treatment, except accumulation of dry matterand ion leakeage. Our results suggestedthat Ca2+and SA may interact to reduce the stress experienced by the plantsin the presence of NaCl.

In order to determine an optimal N, P, K combination for improvingyield, quality and economic efficiency of sweet potato production, an experiment was conducted with 5 inorganic N, P, K combinations. Arandomized complete block design with 3 replications was carried out in spring and winter seasons in Thai Nguyen. The result showed that increased rate of N, P, K lengthened theduration of tuber formation and growth whilst reduced duration ofcanopycover. Increments of N, P, Kalso increased main vinelength, average tuber weight, top growthyield, and harvested root yield.. For spring and winter seasons,the optimum rate was recommended at 70 N + 70 P2O5+ 100 K2O because it gave the highest average tuber weight, harversted yield and profit (50.434.800 VND/ha in srping season and 40.301.200 VND/ha in winter season).

Identifying optimal fertilizer rate and frequency and timing of nitrogen and potassium split application presents one of the nutrient management measures for improvement of mungbean yield on sandy soil in general and on coastal sandy soil in Thanh Hoa province in particular. In the present study, the effect of three NPK rates (LL1, LL2, and LL3) and frequency and timing of NK split applications (TD1, TD2, and TD3) on plant growth, grain yield and economic efficiency of two mungbean varieties were studied. Mungbean cultivars ĐX208 and ĐX16 were grown on coastal sandy soils in the districts of Nga Son and Hoang Hoa and Tinh Gia, respectively, in 2012 and 2013 summer cropping seasons. Plant growth and yield were influenced by the level of fertilizer, timing and frequency of nitrogen and potassium top dress application. For cv. ĐX208, highest fertilizer rate (LL3) resulted in high yield although not significant compared with the control. Fertilizer rate LL3 with TD3 split application resulted in better growth and significantly higher yield as compared with the control (TD1). However, LL2 with TD2 split application brought about highest yield and economic return for ĐX 2008, while for shorter growth duration cv. ĐX16, LL2 with TD2 split applcation resulted in highest yield and economic return.

From March 2016 to April 2017, under the cooperation between Vietnam National University of Agriculture and Extention Centre of Hung Yen province, a demonstration model of Channel catfish (Ictalurus punctatus) pond culture was developed. The modelwas caried out in six householdpondslocated in Van Giang, Khoai Chau, Yen My and Phu Cu districts, Hung Yen province. The Channel catfish with initial body weight of about 31,29± 0,56g/fish were stocked at three densities of 1; 1.5 and 2 fish/m2. Fish were fed commercial pellet containing 30-35% crude protein produced by CJ Master company (label withF8002 and F8003). Fish were fed twice daily at 8:00 AM and 16:00 PM at afeeding rate of 3 - 5% of body weight/day. Results showed that Channel catfish exhibited good growth rate (6.15-7.0 g/fish/day)and high survival rate (94.3-96.4%) and no disease occurred during the experimental period. The Channel catfish stocked ata density of 1 fish/m2yielded better growth, higher survival rate and highereconomic efficiency (248.3-257.4 million VND/ha/year) than those stocked atdensities of 1.5 and 2 fish/m2.

An experiment was undertaken to assess the effects of housing system on welfare in gilts and gestation sows. The experiment was a factorial design with 20 F1 gilts (Landrace x Yorkshire) of similar body weight and age randomly allocated to two housing systems (group rearing vs. invidual rearing, 5 gilts per pen, two pens for each housing system). Welfare assessment was conducted at a fixed day every week in all 3 stages: gilt, from mating to 30 days, and from 31 to 100 gestation days according to recommendations of the Welfare quality® 2009 Protocol. The results showed that at the gilt stage, housing system significantly affected some criteria of animal welfare in gilts, suchs as percentage of feaces on the body, body wound, stereotypies, and exploratory behaviour. At the stage from mating to 30 days, howver, no influence of housing system on all parameters of animal welfare was observed. At the gestation stage from 31 to 100 days, housing system affected several parameters of animal welfare, including shoulder sores, lameness, percentage of feaces on the body, body wound, stereotypies, and exploratory behaviour. Raising sows under group rearing housing system helped to improve some parameters of animal welfare, health and behaviour. However, it was necessary to have solution to reduce aggressive behaviour among sows during initial days of grouping.

In this study, E. coli and Salmonella were isolated from 230 poultry eggs (115 egg shells and 115 egg contents) collected from retail markets located in Hanoi city to examine the prevalence of these bacteria. The results showed that, the egg samples were not contaminated by Salmonella. However, there were 20,0% of egg samples were contaminated with E. Coli. The E. coli contamination rate of the shells was always higher than that of the egg content (p < 0,05). The E. coli contamination rates were similar in duck’s eggs with 30.0% and 11,7% in the shell and egg content, respectively. The isolated E. coli strains resisted against Streptomycin (87.0%), Tetracyclin (78.3%), Trimethoprime (58.7%) and Cephalexin (58.7%). Other antibiotics were resisted by isolated E. coli strains in the range of 21.7% to 47.8%. Only one isolated E. coli strain was susceptible to all tested antibiotics. However, the resistance to the tested antibiotics was found in 30 out of 46 isolated strains. Notably, sevenand three isolated E. coli strains were resistantto 10 and 11 tested antimicrobials, respectively. The widespread resistance may have arisen from misuse or overuse of antimicrobial drugs during poultry husbandry in North Vietnam.

The study aims to evaluate rickets in the population of 856 dogs in some northern provinces including Hanoi, Lang Son, Hai Duong, Hung Yen, Thai Binh, Hai Phong, and Quang Ninh and to identify effective treatment regimens. The results showed that the disease rate varied among 4 different breed groups and 4 age ranges, higher in exotic dog populations in that Béc giêbreed had the highest rate (14.91%). Dogs in the age range from 2 to 4 months had highest prevalence (17.20%) followed by the age range of from 4 to 6, under 2, and above 6 months of age (13.30%; 6.49% and 4.16%, respectively). Intrevenous injection with calcium had high treatment effect (recovery rate 100% after 10 days of treatment). In addition, nursery and nutrition cares played an important role in recovery process.

The research was conducted tocollect semen of Dong Tao cocks, evaluatesemen quality, preserveand artificiallyinseminateDong Tao hens. A total of 62 cocksand420 hens with typical characteristics of Dong Tao breedrearing at households in Dong Tao, Khoai Chau, Hung Yen were selected for the study. The results showedthat the cocks had relatively slow ejaculation reflex. The semen volume, sperm activity and concentration were 0.46 ml, 76.04% and 3.26 billion/ml, respectively. The semen quality in summer was relatively low. The best semen collection interval was once a day. It was possible to use both buffer 1 and 2 to dilute semen, but buffer 1 beingmore appropriate, because after 9 hours of conservation at5oC, the sperm activity remained over50%. With the interval of 3 days between two artificial inseminationsata dose of 150 millionsperms per insemination, the rate of fertilized eggs reached over 84%. Insemination in the evening wasbetter than in the morning. The results suggestedthe applicabilityof artificial insemination for Dong Tao chickens.

This study was conducted to evaluate the effects of different stocking densities on growth and survival rate of black apple snail, Pila polita. There were 4 stocking densities and 3 replicates per treatment as follow: 50, 100, 150, 200 ind./m2. Snails with initial weight (1.6 g), shell height (20.7 mm) and shell width (14.3 mm) were reared in hapanetand fed 50% pellet (Proconco, 18% protein) + 50% vegetable (spinach, 3.4% protein). After 4 monthsof culture, at low stocking densities, the survival rate was higher than that of high density treatments (77.4, 75.6, 73.8 and 68.5% at density 50, 100, 150 and 200 ind./m2, respectively with) (p <0,05). Rearing at 50 ind./m2, snails reached highest body weight, shell height and shell width (31.09 g; 54.90 mm and 43.38 mm, respectively) compared to 100 ind./m2(30.65 g; 53.42 mm and 43.14 mm), 150 ind./m2(30.03 g; 53.61 mm and 42.32 mm) and 200 ind./m2(28.35 g; 53.09 mm và 41.41 mm). At the stocking density of 50 ind./m2snails also hadlowest FR (2.62). It was similar to the density of 100 ind./m2(2,80) and significantlydifferent(p <0.05) compared to 150 ind./m2(3.04) and 200 ind./m2(3.45). Snails raised at 50 ind./m2yieldedthe highest profit (19.535 VND/m2),followedby 100 ind./m2(18.122 VND/m2) and was significantlydifferent(p <0.05) compared to 150 or 200 ind./m2(10.487 - 14.280 VND/m2). The results from this study provide the basic information for further studies to develop culture techniques for Black apple snailculturein the Mekong Delta.

This study aimed to assess the properties of vegetable soil in three communes along the Red River in Thanh Tri district, Hanoi city to establish data base for safe and VietGAPvegetable cultivation. 72 soil samplesand15 vegetablesamples were collected to analyze the chemical, physical and biological properties of soil. Results showed that most of the samples weresandy soiland oflight bulk density. Almost samples haddensity less than 2.7. The data range hada low standard deviation with a confidence interval of ± 0.01 to ± 4.25 (= 0.05). The soilwasfrom lightly acidic to slightly alkaline, but most wasneutral.Total organic carbon and total nitrogen weremoderate,total phosphorus variedfrom medium to high, and total potassium from poor to high. Results of biological analysis indicated that the soil had a higher total number of aerobic bacteria than the total anaerobic bacteria.The earthworms distributed unevenly in the samples,ranging from 9 to 17 individuals. The heavy metal content (Cu, Pb, Zn) in the soil waslower than the allowable limits of heavy metals. Soil properties and content of heavy metals in the soil meet the conditions for safe vegetable cultivation in accordance with the current regulations of the Ministry of Agriculture and Rural Development as well as the standards of safe vegetables of the Ministry of Health.

Soil erosion is one of the main causesof soil degradation. Map of soil erosion risk provides information about location and erosionthreat, thus helpsus incontrolling the impact factors of soil erosion. The aim of this study was to apply spatial analysis methods in GIS to produce the map of soil erosion risk for agricultural land in Tam Nong district, Phu Tho province. Based on expert’s knowledge, followed by Analytic hierarchy process (AHP), we calculated the weight for 5 impact factors to soil erosion: precipitation (49.22%), slope (20.57%), soil types (10.30%), vegetation cover (13.48%) and land use type (6.44%). Spatial analysis techniques were used to over lay all thematic maps with corresponding weights to construct map of soil erosion risk. The results showed, there were 1 650.78 ha of agricultural land that hadhigh risk of erosion (accountingfor 15.16% of the total area)and3 074.07 (28.23%) ha hadmedium risk. The agricultural land with low and no risk of soil erosion accountedfor 40.58% and 16.03%,respectively. Verification in the field indicated that the map of soil erosion risk has high reliability, and reflects the reality of the soil erosion in the study area.

With natural advantages, the alluvıal soils along the Red river play an important role in the development of agriculture to ensure food security and livelihood of local people. Phu Tho province has a large area of alluvıal soils along the Red River (1,515.82 ha), which are mainly used for agricultural purpose with 5 land use types: vegetables, cash crop, sugarcane, fruittrees, and grass. However, the agricultural development on alluvıal soils along the Red River of Phu Tho province has not fully utilized thepotential of alluvial soil. The study was conducted to evaluate the quality of alluvıal soils along the RedRiver as a basis for effective agricultural land use in Phu Tho province. The alluvıal soils along the Red River in Phu Tho are ofsandy loam texture, light acidity with relatively high fertility: OM%: 2.04 to 4.91; N%: 0.11-0.29%, P2O5%: 0.08-0.15, available P2O5: 12.61-17.17 mg / 100g of soil.Total potassium, available potassium, and exchangeable magnesium weremoderate, but the content of exchangeable calcium was high. Soil had low water holding capacity due to its lighttextureleading towater deficit during dry season. Thesoil CEC was not high andthe ability to keep nutrition was limited. In order to improve the quality of the alluvıal soils along the Red River, it is necessary to apply more organicamendments, to limit the conversion of agricultural land to non-agricultural purposesandto increase the area of ​​vegetable cultivation, cash crops, and grassland from ineffective sugarcane areas.

The experiment was arranged in a completely randomized design with two factors, factor A consisted of 4 levels of phenylalanine (0, 50, 100 and 200 ppm), factor B consisted of5 times the phenylalanine treatment (90, 120 150, 180 and 210 days after planting - DAP), and3 replications with3 pots/replication. The results showed that phenylalanine did not affect the growth of turmeric such as number of tillers per clump, number of leaves per clump, number of leaves in main tiller, height of pseudostem, leaf length and leaf breadth. However, the difference in clump weight and content of curcumin was statistically significant at 1%. Treatment at120 DAP resulted inhighest clump weight and content of curcumin(198.7 g/clump and 11.23%,respectively). The clump weight and curcumin contents in the 100 ppm phenylalanine treatment were higher than other concentrations(211.5 g/clump and 12.26%, respectively). Phenylalanine application at120 DAP with the concentration of 100ppm yieldedthe highest clump weight and content of curcumin (279.6 g/clump and 12.4%, respectively) as compared with the remaining treatment groups.

This study was conducted to understand the current development situation of sericulturalproductionin Thai Binh provinceat aspects of economy, society and environment during period 2006 -2015.According to the interviews with 352 producer and statistical reports showed thatproduction size has reduced seriously: famer households reduced 67,2%, mulberry area reduced 65,1%. However, from profound angle, sericultural production developed considerably: mulberry yield increased 13,1%; cocoon yield increased 159%. Although mulberry area reduced a lot, cocoon productivity reduced 9,5% only. Based on analyzing achievements, constraintsand reasons in recent years, the paper proposedsome solutions such as: Local governmentplay leading role; Promotinginformation, training; Supporting establishment of young age silkworm bases; Applying late age silkworm rearing on the floor; Using guarantee high yield varieties; Attracting investment from factors; Enhancingcooperative in linkage of production and marketing; Connecting to traditional silk villages.

Clean water is essential for the livelihood of all people, especially for the poor in the rural areas. A case study using rapid rural appraisal in Tien Lang district showed that 48.2% of people have accessed to the standard 02/BYT clean water. However, there existed several problems in State management of rural clean water at Tien Lang district with regard to effectiveness, equality and sustainability. As a consequence, the proportion of tap water that meets the standard of clean water was still low (approximate 49.7%), the rate of poor people accessing to the standard clean water was only 38.9%, and the percentage of sustainable water supply systems was only 20%. It is, therefore, needed to take clean water supply into consideration towards the goal that 70% people can access to the standard clean water by 2020.

Pig production applying Vietnam Good Animal Husbandry Practices (VietGAHP) is a way for improving competitiveness and sustainable development of pig sector in Vietnam. The study was designed to evaluate the current situation of pig smallholder farms and provide key recommendations for VietGAHP pig production in Cam Giang district, Hai Duong province. The data was collected through survey of 60 pig farmers and descriptive and comparative statistics were employed. Results showed that pig farmers basically met requirements on feed management, water quality, hygene, preservation and use of vaccine, waste management and environmental protection. The main benefits from VietGAHP pig production were reduction of pig diseases and improvement of farmer’s income, especially in the context of rising consumers’ concern about food safety. However, pig farmers also faced difficulties in applying VietGAHP due to the complicated criteria, as well as indifference between VietGAHP and conventional pork prices in market. Key recommendations for VietGAHP pig production were proposed accordingly.

Determination of optimal harvest date for ‘Edor’ longan fruit is a difficult problem for bothgrowers and buyers in the production and trading. The study was conducted to determine the optimal harvest date for longan cv. ‘Edor’. The experiment design was completely randomized with two factors,namely the harvest season and maturitystage. Fruit was harvested from February to Junein the dry season andfrom July to Jamuary in the wet season at 105, 112, 119, 126, 133 and 140 days after fruit set. The results indicated that the ‘Edor’ longan fruit harvested in the wet seasonhad better quality retention than those harvested in the dry season. The fruitshad highest quality when harvested at 119 and 126 days after fruit set and maintained at 20°C for 4 days. The fruit skin color in this period changed from light brown to brown-yellow. The fruitsharvested at 105 and 112 days after fruit set had lower quality. Harvesting fruits at 133 days after fruit set dramatically affected post-harvest storability.