| 1. |
- Duy, Duong The, et al.
(författare)
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Assessing the effects of social capital on trade credit in shrimp farming in the Mekong Delta, Vietnam
- 2024
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Ingår i: Aquaculture Economics & Management. - 1365-7305 .- 1551-8663.
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Tidskriftsartikel (refereegranskat)abstract
- This study assesses and identify major factors of social capital that affect the use of trade credit among shrimp farmers and how these contribute to and affect the profits of households in coastal provinces of the Mekong Delta, Vietnam. Data was collected through observations, informal discussions, and interviews with 364 shrimp farmers from the Ca Mau, Bac Lieu, Ben Tre and Tra Vinh provinces. The Probit and Tobit regression models were applied to analyze and evaluate the effect of social capital on the use of trade credit and the amount of trade credit used by farmers. The results show that many social capital factors affect the use of trade credit by shrimp farmers in the investigated areas, including in descending order of importance: profit, wholesale agents, colleague-friend-family line-neighbor, and trust. Besides the factors above, other factors such as agricultural land value, households’ income, distance, experiences in shrimp production, households’ assets, savings, profits of the previous crop, and the average household income had also an effect on trade use and amount of trade credit used by shrimp farming households.
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| 2. |
- Thanh, Dang Trung, et al.
(författare)
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Effects of organic fertilizers produced from fish pond sediment on growth performances and yield of Malabar and Amaranthus vegetables
- 2023
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Ingår i: Frontiers in Sustainable Food Systems. - : Frontiers Media SA. - 2571-581X. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- The increasing intensification of aquaculture production requires the development of strategies to reduce its environmental impacts such as the pollution caused by the discharge of nutrient-rich sediments into local water bodies. This research was undertaken to investigate and evaluate the effect of using organic fertilizers produced from the pond sludge of freshwater snakehead fish (Channa striata) composted with organic amendments of peanut shells and coir fiber on growth performance indices and yields of Malabar spinach (Basella alba L.) and Amaranthus cruentus (Amaranthus L.) vegetables in the dry and wet seasons. An organic fertilizer quality experiment showed that the richest nutrient contents of the produced organic fertilizer were achieved when using 30% sludge mixed with 70% organic amendments (50% peanut shells + 50% coir fiber). This was selected and used for a vegetable cultivation experiment. For the reference treatment, only chemical fertilizer was applied, while in the other four treatments, 25, 50, 75, and 100% of the chemical fertilizer were substituted with the organic fertilizer. A 25–50% reduction in the chemical fertilizer application resulted in better growth performance indices and final yields than the other treatments, including the reference treatment, for both crops. The highest yields of Malabar spinach and Amaranthus cruentus vegetables were found in Treatment 3 (50% chemical fertilizer combined with 50% organic fertilizer), followed by Treatment 2 (25% organic fertilizer combined with 75% inorganic fertilizer) (P < 0.05). The results show that the reuse of sludge from snakehead fish ponds mixed with agricultural by-products as organic fertilizer for vegetables not only improves vegetable productivity but also reduces the costs of chemical fertilizer and decreases environmental pollution.
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| 3. |
- Berg, Håkan, et al.
(författare)
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An ecological economic comparison between integrated rice-fish farming and rice monocultures with low and high dikes in the Mekong Delta, Vietnam
- 2023
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Ingår i: Ambio. - 0044-7447 .- 1654-7209. ; 52:9, s. 1462-1474
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Tidskriftsartikel (refereegranskat)abstract
- This study makes an ecological economic comparison between three different rice farming strategies in the Mekong Delta. Interviews were made with 30 farmers with two crops of rice and low dikes (2RLd), 30 farmers with three crops of rice and high dikes (3RHd) and 18 farmers with two crops of rice and one crop of fish (2RF). 2RF farmers had the highest annual net income and benefit cost ratio, because of low production costs and high yields of rice and fish. 2RLd farmers had the lowest annual net income. 3RHd had the highest annual rice yield, but also used the highest amount of rice seeds and agrochemicals, generating the lowest benefit cost ratio. Most farmers (70%) preferred two crops because of a higher production efficiency. High dikes and frequent use of pesticides and fertilizers were seen to decrease the water and rice quality, connectivity and biodiversity in farms with three crops. It is concluded that rice farming with two crops, and especially if integrated with fish and applying IPM, provides a sustainable alternative to rice farming with three crops and high dikes, because it makes use of the high connectivity within the rice-field ecosystem for an efficient production of healthy food through increased recycling of nutrients and natural pest control mechanisms.
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| 4. |
- Berg, Håkan, et al.
(författare)
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Stakeholders assessment of status and trends of ecosystem services in the Mekong Delta for improved management of multifunctional wetlands
- 2023
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Ingår i: Journal of Environmental Management. - 0301-4797 .- 1095-8630. ; 338
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Tidskriftsartikel (refereegranskat)abstract
- Increased agriculture and aquaculture production in the Mekong Delta during the last two decades has improved farmers' income, national export earnings and reduced poverty, but has also impacted on the environment and ecosystem services (ES) of importance to peoples' livelihoods and well-being. Through group discussions, interviews and questionnaires, this study assesses stakeholders’ perceptions of the status and trends of ES in the Mekong Delta and how these have been influenced by agriculture development. 15 of 24 ES were assessed to be impacted negatively by agriculture intensification, and especially supporting and regulating ES (SRES). Only a few provisioning ES (PrES), related to farming, were assessed to be in a good and stable supply, because of human interventions to create favorable conditions for these ES. Among the ten highest ranked ES, eight belonged to PrES and two belonged to SRES. There was a positive correlation between rank and awareness of ES. The supply of most SRES was perceived to be in a low and declining status and assessed to be in a high need for improved management. Some ES, such as pest-control had been complemented with human-made substitutes, such as pesticides, which however sometimes weakened rather than strengthened the ES. Cultural ES (CES) were often ranked lower and of less management concern than the other groups of ES. It is concluded that future agriculture strategies need a more balanced management of ES for a long-term production of healthy food and increased resilience of the Mekong Delta to cope with future challenges, such as climate change and upstream dams.
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| 5. |
- Da, Chau Thi, et al.
(författare)
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Digestibility of dietary components and amino acids in animal and plant protein feed ingredients in striped catfish (Pangasianodon hypophthalmus) fingerlings
- 2013
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Ingår i: Aquaculture Nutrition. - : Hindawi Limited. - 1353-5773 .- 1365-2095. ; 19, s. 741-750
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Tidskriftsartikel (refereegranskat)abstract
- The apparent digestibility (AD) of dietary components, energy and essential amino acids (EAA) of selected locally available animal and plant protein feed ingredients in striped catfish (Pangasianodon hypophthalmus) fingerlings was studied. The AD of the test ingredients (ADi) differed (P<0.05) and ranged from 81.1% to 90.8%, for ADi(DM), from 84.0% to 95.0% for ADi(CP), from 78.4% to 86.9% for ADi(OM) and from 79.0% to 87.8% for ADi(GE). The highest ADi(DM), ADi(CP) and ADi(OM) in the test ingredients were found for shrimp head meal, catfish by-product meal, golden apple snail and groundnut cake, while the lowest values were obtained for earthworm meal and rice bran. The highest ADi(GE) was found in rice bran, followed by golden apple snail and catfish by-product meal, while there were no differences (P<0.05) between the other test ingredients, except for earthworm meal. The AD of total and individual EAA was high in catfish by-product meal and shrimp head meal, followed by decreasing AD in golden apple snail, groundnut cake, rice bran and earthworm meal ingredients (P<0.05). The low AD of earthworm meal may limit its potential to be used as replacement for fish meal in the feed.
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| 6. |
- Da, Chau Thi, et al.
(författare)
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Digestibility of dietary components and amino acids in plant protein feed ingredients in striped catfish (Pangasianodon hypophthalmus) fingerlings
- 2013
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Ingår i: Aquaculture Nutrition. - : Hindawi Limited. - 1353-5773 .- 1365-2095. ; 19, s. 619-628
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Tidskriftsartikel (refereegranskat)abstract
- The apparent digestibility (AD) of dietary components, energy and essential amino acids (EAA) of selected locally available plant protein feed ingredients in striped catfish (Pangasianodon hypophthalmus) fingerlings was studied. The AD of the test ingredients (ADi) differed (P < 0.05) and ranged from 66.2 to 89.6% for ADiDM, from 63.6 to 91.3% for ADiCP, from 65.4 to 85.3% for ADiOM and from 69.8 to 89.3% for ADiGE. The highest ADiDM, ADiOM and ADiGE in the test ingredients was obtained for broken rice, maize meal and soybean meal, while the lowest values were obtained for duckweed meal. Soybean meal and duckweed meal had the highest ADiCP, while there were no differences (P > 0.05) between the other test ingredients. The AD of total and individual EAA was higher in soybean meal, duckweed meal and broken rice than in the other test feed ingredients (P < 0.05). The lowest AD of individual EAA was found in maize meal, followed by cassava leaf meal and sweet potato leaf meal (P < 0.05). The low AD of individual plant feed ingredients may limit their potential to be used as replacement for fish meal in the feed.
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| 7. |
- Da, Chau Thi, et al.
(författare)
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Evaluation of local feed resources as alternatives to fish meal in terms of growth performance, feed utilisation and biological indices of striped catfish (Pangasianodon hypophthalmus) fingerlings
- 2012
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486 .- 1873-5622. ; 364-365, s. 150-156
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Tidskriftsartikel (refereegranskat)abstract
- A 16-week feeding experiment was conducted to evaluate growth performance, feed utilisation and body indices of striped catfish (Pangasianodon hypophthalmus) fed diets where fish meal protein was replaced with protein from local feed resources. The reference diet contained fish meal as the main crude protein (CP) source, whilst in the six test diets 20 to 100% of the fish meal CP was replaced with CP from local ingredients (soybean meal, cassava leaf meal, sweet potato leaf meal, groundnut cake, golden apple snail meal and shrimp head meal). Final body weight (BW) and total weight gain (WG) were lowest for the cassava leaf meal diet (P < 0.05), whilst there were no differences in BW and WG between the other diets. Final BW, WG and daily weight gain were numerically highest for the shrimp head meal diet. Fish survival rate, feed intake, feed utilisation and fish fillet proportion did not differ between the reference diet and the test diets (P > 0.05). The viscera-somatic, hepato-somatic, kidney and intra-peritoneal fat indices differed between treatments (P < 0.05). The results suggest that fish meal protein in feed for striped catfish fingerlings can be replaced with protein from locally available plant and animal ingredients without compromising growth performance, feed utilisation and carcass traits.
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| 8. |
- Da, Chau Thi
(författare)
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Evaluation of locally available feed resources for striped catfish (Pangasianodon hypophthalmus)
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis investigated and compared inputs and outputs, economic factors and current feed use in small-scale farming systems producing striped catfish (Pangasianodon hypophthalmus) in the Mekong Delta. The nutrient content of locally available natural feed resources for striped catfish was determined and growth performance, feed utilisation and body indices were analysed in pond-cultured striped catfish fed diets where fish meal protein was replaced with protein from local feed resources. A survey showed that around 15 feed ingredients are used in striped catfish pond culture in the region. The combination of feed ingredients used in farm-made feeds varied among fish farms. The cost of producing 1 kg of fish using farm-made feeds was usually 8˗10% lower than that of using commercial feeds. Digestibility trials on selected potential feedstuffs showed that the apparent digestibility (AD) of DM, CP, OM and energy was highest in soybean meal, groundnut cake, broken rice, shrimp head meal, golden apple snail and catfish by-product meal and earthworm meal, whilst the digestibility was in lower cassava leaf meal and sweet potato leaf meal. The average digestibility of most essential amino acids (EAA) in selected feed ingredients was high (range 70˗92%), indicating high protein quality of these feedstuffs. In general, the AD of individual EAA was high for all diets except those with cassava leaf meal, rice bran and earthworm meal, where the AD of EAA was reduced. Two different growth experiments with the same diet (20˗100% replacement of fish meal) were performed in an indoor and an outdoor culture system. A significant finding was that daily weight gain (DWG) was much higher (3.2˗ to 6˗fold) in outdoor culture conditions compared with indoor. Feed conversion rate and feed utilisation were also 0.2˗0.7 units (kg feed DM/kg weight gain) higher in the outdoor system. The results suggest that fish meal protein in feed for striped catfish fingerlings can be replaced with protein from locally available plant and animal ingredients without compromising growth performance, feed utilisation or carcass traits.
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| 9. |
- Da, Chau Thi, et al.
(författare)
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Growth performance, feed utilisation and biological indices of Tra catfish (Pangasianodon hypophthalmus) cultured in net cages in pond fed diets based on locally available feed resources
- 2016
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Ingår i: International Aquatic Research. - : Springer Science and Business Media LLC. - 2008-4935 .- 2008-6970. ; 8, s. 309–321-
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Tidskriftsartikel (refereegranskat)abstract
- The feeding experiment was conducted to evaluate the efficacy of locally available feed resources for Tra catfish (Pangasianodon hypophthalmus) cultured a series of 21 hapa net cages installed in the earthen pond during a 4-month period. The reference diet contained fish meal as the main crude protein (CP) source, whilst in the seven test diets 20-100 % of the fish meal CP was replaced with CP from local feed ingredients: groundnut cake (GNC), cassava leaf meal (CSLM), sweet potato leaf meal (SPLM), soybean meal (SBM), golden apple snail meal (GASM) and shrimp head meal. There were differences (p\0.05) among diets in final body weight, total weight gain, daily weight gain, specific growth rate, viscera-somatic weight (VSI%), hepato-somatic index (HIS%) and intra-peritoneal fat (IPF%). The respective values for the shrimp head meal diet were numerically highest, followed in descending order by the reference, GASM, GNC, SPLM, CSLM and SBM diet. Food conversion ratio, fish survival rate, total feed intake, feed utilisation, fish fillet and kidney proportions did not differ among the reference and test diets (p[0.05). However, the viscera-somatic, hepato-somatic, kidney and intra-peritoneal fat indices differed among treatments (p\0.05). These data show that fish meal protein can be replaced with protein from locally available plant and animal feed ingredient resources in feed cultured in net cages in pond for Tra catfish fingerlings in effectively compromising growth performance, feed utilisation or carcass traits of fish.
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| 10. |
- Da, Chau Thi, et al.
(författare)
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Recycled pangasius pond sediments as organic fertilizer for vegetables cultivation : strategies for sustainable food production
- 2023
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Ingår i: Clean Technologies and Environmental Policy. - : Springer Science and Business Media LLC. - 1618-954X .- 1618-9558. ; 25:2, s. 369-380
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Tidskriftsartikel (refereegranskat)abstract
- Intensive Pangasius aquaculture farming contributes to increased income and profits in Vietnam, but is also associated with many environmental problems, including pollution from nutrient-rich water and sediments that are released into the environment. This article investigates the feasibility of using Pangasius pond sediments (PPS) in combination with amendments of rice straw (RS) to fertilize cucumber (Cucumis sativus L.) and water spinach (Ipomoea aquatica Forssk) plant. The results showed that mixing a ratio of 30% PPS with 70% RS produced the highest nutrient concentrations. The study demonstrates that organic fertilizer produced from PPS in combination with chemical fertilizer can replace 2575% of the inorganic fertilizers used as a nutrient source for cucumber and water spinach, and also increase the vegetable production. The highest yields were found for treatment PPS-3 (a combination of 50% chemical fertilizer and 50% organic fertilizer used on cucumber), and for treatment PPSRS-4 (a combination of 25% chemical fertilizer and 75% organic fertilizer used on water spinach) in both the wet and dry season (P˂0.05). The lowest yields were found when growing cucumbers and water spinach either with 100% organic fertilizer (the treatment PPS-5) or with 100% chemical fertilizer (the control treatment PPS-1), respectively (P˂0.05). Overall, the results indicated that the recycling of PPS as organic fertilizer and chemical fertilizer in combination for vegetable cultivation is more environmentally friendly as compared to using only chemical fertilizers.
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