Staff Publications

Staff Publications

  • external user (warningwarning)
  • Log in as
  • language uk
  • About

    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

    We have a manual that explains all the features 

    Records 1 - 20 / 31

    • help
    • print

      Print search results

    • export

      Export search results

    Check title to add to marked list
    Comparative sustainability analysis of aquasilviculture and other shrimp farming types in the Mekong Delta, Vietnam
    Bosma, R.H. ; Hiep, Tong Quoc ; Jansen, Jan ; Tran Thi Phung, H. ; Dang Tri, Van Pham - \ 2019
    In: Book of abstracts of the 12th Asian Fisheries & Aquaculture Forum (AFAF). - - p. 198 - 198.
    In this study, we compared the sustainability of the Integrated Mangrove Shrimp
    Aquasilvi-culture (IMSA) with that of the Intensive (INT), Improved Extensive (IE)
    and the hybrid forms of farming shrimp in Tra Vinh, a coastal province in Mekong delta, Vietnam. To quantify sustainability, we identified 20 indicators representing one of the three fields of sustainability: ecological, financial and social. Our study did not quantify the ecosystems services because aside from aquatic products, the local IMSA provides only timber. We surveyed a total of 132 farms. Of these, 103 farms were non-hybrid consisting of 26 IMSA, 48 INT and 29 IE. The hybrids were either IE-INT (18), INT-IMSA (7), or IE-IMS (4). We also collected online the rating of 38 experts for the sustainability indicators. Furthermore, to fit all data in one graph on a scale of 1 to 100 (Zhang et al 2012), we transformed the original average values of the parameters.The expert panel rated highest the economic indicators, followed by social and ecological indicators. INT and IMSA farms were found to be significantly different in eight farm parameters; while IE and hybrid farms differed in five parameters. INT farms used more chemicals but frequency of disease outbreaks remained higher than in IE and IMSA. However INT farms scored higher for most economic indicators, while IMSA scored better for social and ecological indicators. Results of the study show that low cost start-up and operation, as well as the presence of mangroves, can reduce the social and ecological risks of shrimp farms located in fragile coasts of tropical deltas. Although shrimp aquasilviculture has a small contribution to the shrimp value chain, IMSA gives farmers an option to farm certified organic shrimp. More importantly, appropriate application of IMSA can also contribute to sustaining coastal livelihoods during sea level rise induced by climatic changes.
    Agent based modelling to support policies on shrimp farming and mangrove in the Vietnamese Mekkong Delta
    Hiep, Tong Quoc ; Pham Dang, Tri Van; Ligtenberg, A. ; Bosma, R.H. ; Tran Thi Phung, H. ; Bregt, A.K. - \ 2019
    In: Book of abstracts of the 12th Asian Fisheries & Aquaculture Forum (AFAF). - - p. 322 - 322.
    Coastal zones are vulnerable to changes in ecology due to industries and
    urbanization, and in upstream water sources and sea level. Designing policies
    considering all aspects is challenging. NGO's advocate balancing ecology and
    economy, while GO stimulates farmers to shift to intensive (INT) shrimp farming.
    Most farmers intensify only part of their improved-extensive (IE) or integrated
    mangrove shrimp (IMS) farms into so-called hybrid systems. Using an agent-based model a spatially explicit assessment of farmers' choices and local orientation was simulated for three areas and three scenarios. The baseline scenario, assuming the increase of INT due to GO policies, shows that planning fails due to a gap between the ambitions of local authorities and the outcomes for farmers. The Organic scenario confirmed the trend towards more INT while just maintaining IMS, despite financial support. In the Climate Change scenario, the income of shrimp farming decreased due to the increased risks.
    Comparative sustainability analysis of aquasilviculture and other shrimp farming types in the Mekong Delta, Vietnam
    Bosma, Roel ; Tong Quoc, Hiep ; Jansen, Jan ; Tran Thi Phung, Ha ; Dang Tri, Van Pham - \ 2019
    In this study, we compared the sustainability of the Integrated Mangrove Shrimp
    Aquasilvi-culture (IMSA) with that of the Intensive (INT), Improved Extensive (IE)
    and the hybrid forms of farming shrimp in Tra Vinh, a coastal province in Mekong
    delta, Vietnam. To quantify sustainability, we identified 20 indicators representing one of the three fields of sustainability: ecological, financial and social. Our study did not quantify the ecosystems services because aside from aquatic products, the local IMSA provides only timber. We surveyed a total of 132 farms. Of these, 103 farms were non-hybrid consisting of 26 IMSA, 48 INT and 29 IE. The hybrids were either IE-INT (18), INT-IMSA (7), or IE-IMS (4). We also collected online the rating of 38 experts for the sustainability indicators. Furthermore, to fit all data in one graph on a scale of 1 to 100 (Zhang et al 2012), we transformed the original average values of the parameters.The expert panel rated highest the economic indicators, followed by social and ecological indicators. INT and IMSA farms were found to be significantly different in eight farm parameters; while IE and hybrid farms differed in five parameters. INT farms used more chemicals but frequency of disease outbreaks remained higher than in IE and IMSA. However INT farms scored higher for most economic indicators, while IMSA scored better for social and ecological indicators. Results of the study show that low cost start-up and operation, as well as the presence of mangroves, can reduce the social and ecological risks of shrimp farms located in fragile coasts of tropical deltas. Although shrimp aquasilviculture has a small contribution to the shrimp value chain, IMSA gives farmers an option to farm certified organic shrimp. More importantly, appropriate application of IMSA can also contribute to sustaining coastal livelihoods during sea level rise induced by climatic changes.
    Agent based modelling to support policies on shrimp farming and mangrove in the Vietnamese Mekkong Delta
    Tong Quoc, Hiep ; Dang Tri, Van Pham ; Ligtenberg, Arend ; Bosma, Roel ; Tran Thi Phung, Ha ; Bregt, Arnold - \ 2019
    Coastal zones are vulnerable to changes in ecology due to industries and
    urbanization, and in upstream water sources and sea level. Designing policies
    considering all aspects is challenging. NGO's advocate balancing ecology and
    economy, while GO stimulates farmers to shift to intensive (INT) shrimp farming.
    Most farmers intensify only part of their improved-extensive (IE) or integrated
    mangrove shrimp (IMS) farms into so-called hybrid systems. Using an agent-based model a spatially explicit assessment of farmers' choices and local orientation was simulated for three areas and three scenarios. The baseline scenario, assuming the increase of INT due to GO policies, shows that planning fails due to a gap between the ambitions of local authorities and the outcomes for farmers. The Organic scenario confirmed the trend towards more INT while just maintaining IMS, despite financial support. In the Climate Change scenario, the income of shrimp farming decreased due to the increased risks.
    Drought and conflicts at the local level: Establishing a water sharing mechanism for the summer-autumn rice production in Central Vietnam
    Huynh, Chuong Van; Scheltinga, Catharien Terwisscha van; Pham, Ty Huu ; Duong, Non Quoc ; Tran, Phuong Thi ; Nguyen, Linh Hoang Khanh ; Pham, Tung Gia ; Nguyen, Ngoc Bich ; Timmerman, Jos - \ 2019
    International Soil and Water Conservation Research 7 (2019)4. - ISSN 2095-6339 - p. 362 - 375.
    Adaptation - Agriculture - Climate change - Governance - Rice production - Water sharing

    In recent years, water for agricultural production gradually became a significant challenge in the context of climate change in Vietnam. Sustainable solutions are required, which consider the use of resources for both human needs and ecology, and that account for the equitable distribution and the livelihood of the farmers now and in the future. In particular, the farmers in the province of Quang Nam facing water shortage in the cultivation of paddy in the summer-autumn season. Conflicts arise regarding the sharing of the water between the farmers, the drinking water company and the hydropower company. In the context of climate change, the water shortage is expected to increase in the future. The article presents the results of participatory action research (PAR) approach to develop a local level mechanism for water sharing, in which stakeholders actively participated. Water sharing mechanism was developed, envisioning a sustainable solution for inclusive water sharing. The mechanism was successfully implemented in two cases, one at commune level (Tho stream) and one at the district level (Mo stream). The participatory approach proved to be successful in setting up a broadly acceptable mechanism that will need to be further incorporated in the institutional set-up.

    Raising the Stakes: Cassava Seed Networks at Multiple Scales in Cambodia and Vietnam
    Delaquis, Erik ; Andersen, Kelsey F. ; Minato, Nami ; Cu, Thuy Thi Le ; Karssenberg, Maria Eleanor ; Sok, Sophearith ; Wyckhuys, Kris A.G. ; Newby, Jonathan C. ; Burra, Dharani Dhar ; Srean, Pao ; Phirun, Iv ; Le, Niem Duc ; Pham, Nhan Thi ; Garrett, Karen A. ; Almekinders, Conny J.M. ; Struik, Paul C. ; Haan, Stef de - \ 2018
    Frontiers in Sustainable Food Systems 2 (2018). - ISSN 2571-581X - 21 p.
    Cassava is one of the most important annual crops in Southeast Asia, and faces increasing seed borne pest and disease pressures. Despite this, cassava seed systems have received scant research attention. In a first analysis of Vietnamese and Cambodian cassava seed systems, we characterized existing cassava seed systems in 2016–2017 through a farmer survey based approach at both national and community scales, with particular focus on identifying seed system actors, planting material management, exchange mechanisms, geographies, and variety use, and performed a network analysis of detected seed movement at the provincial level. Despite their status as self-organized “informal” networks, the cassava seed systems used by farmers in Vietnam and Cambodia are complex, connected over multiple scales, and include links between geographically distant sites. Cassava planting material was exchanged through farmer seed systems, in which re-use of farm-saved supply and community-level exchanges dominated. At the national level, use of self-saved seed occurred in 47 and 64% of seed use cases in Cambodia and Vietnam, respectively. Movement within communes was prevalent, with 82 and 78% of seed provided to others being exchanged between family and acquaintances within the commune in Cambodia and Vietnam, respectively. Yet, meaningful proportions of seed flows, mediated mostly by traders, also formed inter-provincial and international exchange networks, with 20% of Cambodia's seed acquisitions imported from abroad, especially neighboring Vietnam and Thailand. Dedicated seed traders and local cassava collection points played important roles in the planting material distribution network at particular sites. Sales of planting material were important means of both acquiring and providing seed in both countries, and commercial sale was more prevalent in high-intensity than in low-intensity production sites. Considerable variability existed in local seed networks, depending on the intensity of production and integration with trader networks. Adapted innovations are needed to upgrade cassava seed systems in the face of emerging pests and diseases, taking into account and building on the strengths of the existing systems; including their social nature and ability to quickly and efficiently distribute planting materials at the regional level.
    Technical inefficiency of Vietnamese pangasius farming : A data envelopment analysis
    Anh Ngoc, Pham Thi ; Gaitán-Cremaschi, D. ; Meuwissen, Miranda P.M. ; Le, Tru Cong ; Bosma, Roel H. ; Verreth, Johan ; Lansink, Alfons Oude - \ 2018
    Aquaculture Economics & Management 22 (2018)2. - ISSN 1365-7305 - p. 229 - 243.
    Aquaculture - bootstrap truncated regression - data envelopment analysis - inefficiency - pangasius
    Vietnamese pangasius farming needs to produce efficiently to compete in world markets. This study investigates the input- and output-specific technical inefficiency of Vietnamese pangasius farmers. First, we used a Russell-type (input–output) directional distance function to estimate the input- and output-specific technical inefficiency. Second, we applied a bootstrap truncated regression to analyze the factors influencing these technical inefficiencies. Results show that the main challenges for enhancing the performance of Vietnamese pangasius production are inadequate use of capital assets (inefficiency of 42%) and improper methods to achieve higher fish yield (inefficiency of 30%). Input-specific technical inefficiency (pond area and feed) is negatively associated with the experience and education level of pangasius farmers. Location of the farm in a saltwater intrusion area is positively associated with the inefficiency of producing fish. Outcomes of this study are useful to identify successful strategies to minimize the use of inputs while simultaneously maximizing fish production.
    Price transmission along the Vietnamese pangasius export chain
    Pham, Thi Anh Ngoc ; Meuwissen, Miranda P.M. ; Le, Tru Cong ; Bosma, Roel H. ; Verreth, Johan ; Oude Lansink, Alfons - \ 2018
    Aquaculture 493 (2018). - ISSN 0044-8486 - p. 416 - 423.
    Price transmission in international supply chains is important to ensure that price premiums paid by consumers for environmental sustainability labels are transmitted upstream to farmers. This facilitates investment in sustainable aquaculture systems. This study analyzes the price transmission from the international retail stage to the Vietnamese farm, focusing on frozen pangasius fillets. We used monthly nominal prices at farm and export stages in Vietnam, and at wholesale and retail stages in Poland for the period from August 2010 to December 2014. Price signals at the Polish retail stage were found to transmit back to the wholesale, export, and farm stages. Moreover, price transmission from wholesale to export and from export to farm is characterized by both short- and long-run symmetries. In the short run, retailers tend to transmit only wholesale price increases to their customers and wholesalers transmit only retail price increases to exporters. A long-run relationship between retailers and wholesalers is absent, thereby reducing the ability of chain actors to respond to all market signals, including downward changes.

    Given the delay in price transmission in the short run, the introduction of business-to-business electronic trading or auction markets might reduce this delay along the retail, wholesale, export, and farm stages. To enhance the long-run price relationship in the wholesale-retail market, more retailers should enter the pangasius market. The transmission of price changes from Polish markets back to Vietnamese pangasius farmers is a positive signal for farmers to invest in sustainable production methods, as consumer price premiums likely flow back to the farm.
    Establishing a local water-sharing mechanism in Vietnam
    Chuong, Huynh Van; Ty, Pham Huu ; Terwisscha van Scheltinga, Catharien ; Non, Duong Quoc ; Linh, Nguyen Hoang Khanh ; Phuong, Tran Thi ; Ngoc, Nguyen Bich ; Tung, Pham Gia - \ 2016
    Tropicultura 34 (2016)Special issue. - ISSN 0771-3312 - p. 116 - 116.
    Climate change - Drought - Irrigated rice - Vietnam - Water conflict
    Economic analysis of technological innovations to improve sustainability of pangasius production in Vietnam
    Ngoc, Pham Thi Anh - \ 2016
    Wageningen University. Promotor(en): Alfons Oude Lansink; Johan Verreth, co-promotor(en): Miranda Meuwissen. - Wageningen : Wageningen University - ISBN 9789462579880 - 141
    fish production - fishes - innovations - economic analysis - sustainability - fish culture - vietnam - visproductie - vissen - innovaties - economische analyse - duurzaamheid (sustainability) - visteelt - vietnam

    In response to increasing concerns about sustainable production, a growing number of European customers expect seafood products to be certified, for example by the Aquaculture Stewardship Council (ASC) certification. Water purification technologies such as Recirculating Aquaculture Systems (RAS) could be a potential solution to reduce waste discharge and to improve water quality in fish ponds as a response to environmental regulations. In order to provide useful insights to consider investments in RAS, the overall objective of this thesis was to perform an economic analysis of technological innovations such as RAS to improve the sustainability of pangasius production in Vietnam.

    This thesis first uses Data Envelopment Analysis to measure input- and output-specific technical and scale inefficiency of pangasius farmers in the traditional system and uses a bootstrap truncated regression to assess the impact of farmers’ demographics and farm characteristics on these technical inefficiencies. Second, the economic feasibility of RAS in pangasius farming is analysed using a capital budgeting approach and stochastic simulation accounting for uncertainty in key parameters. Next, key determinants influencing the adoption of RAS by pangasius farmers are investigated using a choice experiment. Finally, price transmission along the international supply chain of pangasius, from the Vietnamese farm to the Polish retail stage is analysed using a vector autoregressive error correction model framework.

    The results show that inadequate management skills in using capital assets and improper methods for producing fish are the main challenges for enhancing the performance of Vietnamese pangasius production. Location of the farm in a saltwater intrusion area is positively associated with inefficiency of producing fish. The results suggest further that when shifting from the traditional system to RAS, the Net Present Value (NPV) of the investment in RAS is expected to substantially increase, for both medium (1-3 ha) and large (equal or greater than 3 ha) farms. Lack of trust in receiving a price premium, inadequate access to finance and uncertainty about the actual performance of RAS systems are constraints for the adoption of RAS. Finally, our study provides evidence that price signals at the Polish-Vietnamese retail stage were transmitted back to wholesale, export and Vietnamese pangasius farms stages.

    Colonization of Enteroaggregative Escherichia coli and Shiga toxin-producing Escherichia coli in chickens and humans in southern Vietnam
    Trung, Nguyen Vinh ; Nhung, Hoang Ngoc ; Carrique-Mas, Juan J. ; Mai, Ho Huynh ; Tuyen, Ha Thanh ; Campbell, James ; Nhung, Nguyen Thi ; Minh, Pham Van; Wagenaar, Jaap A. ; Mai, Nguyen Thi Nhu ; Hieu, Thai Quoc ; Schultsz, Constance ; Hoa, Ngo Thi - \ 2016
    BMC Microbiology 16 (2016)1. - ISSN 1471-2180
    Chicken - E. coli - EAEC - Humans - STEC - Vietnam

    Background: Enteroaggregative (EAEC) and Shiga-toxin producing Escherichia coli (STEC) are a major cause of diarrhea worldwide. E. coli carrying both virulence factors characteristic for EAEC and STEC and producing extended-spectrum beta-lactamase caused severe and protracted disease during an outbreak of E. coli O104:H4 in Europe in 2011. We assessed the opportunities for E. coli carrying the aggR and stx genes to emerge in 'backyard' farms in south-east Asia. Results: Faecal samples collected from 204 chicken farms; 204 farmers and 306 age- and gender-matched individuals not exposed to poultry farming were plated on MacConkey agar plates with and without antimicrobials being supplemented. Sweep samples obtained from MacConkey agar plates without supplemented antimicrobials were screened by multiplex PCR for the detection of the stx1, stx2 and aggR genes. One chicken farm sample each (0.5 %) contained the stx1 and the aggR gene. Eleven (2.4 %) human faecal samples contained the stx1 gene, 2 samples (0.4 %) contained stx2 gene, and 31 (6.8 %) contained the aggR gene. From 46 PCR-positive samples, 205 E. coli isolates were tested for the presence of stx1, stx2, aggR, wzx O104 and fliC H4 genes. None of the isolates simultaneously contained the four genetic markers associated with E. coli O104:H4 epidemic strain (aggR, stx2, wzx O104 and fliC H4 ). Of 34 EAEC, 64.7 % were resistant to 3rd-generation cephalosporins. Conclusion: These results indicate that in southern Vietnam, the human population is a more likely reservoir of aggR and stx gene carrying E. coli than the chicken population. However, conditions for transmission of isolates and/or genes between human and animal reservoirs resulting in the emergence of highly virulent E. coli strains are still favorable, given the nature of'backyard' farms in Vietnam.

    Apports des typologies d'exploitations aux démarches de conception en agriculture de conservation: Une étude de cas dans le nord du Vietnam
    Hauswirth, Damien ; Pham, Thi-Sen ; Wery, Jacques ; Tittonell, Pablo ; Jourdain, Damien ; Affholder, François - \ 2015
    Cahiers Agricultures 24 (2015)2. - ISSN 1166-7699 - p. 102 - 112.
    Cropping systems - Direct seeding - Farming systems - Mountain farming - Mulch - Sustainability

    Conservation agriculture (CA) is considered a possible option for reducing the environmental impact of tilled maize on sloping land in two mountainous districts of northern Vietnam. Within this context, our study aimed at building a regional farm typology that can support the design of CA cropping systems, suiting different farm types. 411 maize-producing farms were surveyed. Using multivariate analysis, we identified 5 farm types with contrasting resources and sustainability performances. We discuss the range of possible CA systems to be designed for each type, according to its specific constraints and opportunities. We especially consider diverse intensification levels and kinds of cover plants. We propose the development of farm models to further explore the economic attractiveness of the options selected for each type.

    Prevalence and risk factors for carriage of antimicrobial-resistant Escherichia coli on household and small-scale chicken farms in the Mekong Delta of Vietnam
    Nguyen, Vinh Trung ; Carrique-Mas, Juan J. ; Ngo, Thi Hoa ; Ho, Huynh Mai ; Ha, Thanh Tuyen ; Campbell, James I. ; Nguyen, Thi Nhung ; Hoang, Ngoc Nhung ; Pham, Van Minh ; Wagenaar, Jaap A. ; Hardon, Anita ; Thai, Quoc Hieu ; Schultsz, Constance - \ 2015
    Journal of Antimicrobial Chemotherapy 70 (2015)7. - ISSN 0305-7453 - p. 2144 - 2152.
    Antimicrobial resistance - Antimicrobial use - Poultry - Treatment incidence

    Objectives: To describe the prevalence of antimicrobial resistance among commensal Escherichia coli isolates on household and small-scale chicken farms, common in southern Vietnam, and to investigate the association of antimicrobial resistance with farming practices and antimicrobial usage. Methods: We collected data on farming and antimicrobial usage from 208 chicken farms. E. coli was isolated from boot swab samples using MacConkey agar (MA) and MA with ceftazidime, nalidixic acid or gentamicin. Isolates were tested for their susceptibility to 11 antimicrobials and for ESBL production. Risk factor analyses were carried out, using logistic regression, at both the bacterial population and farm levels. Results: E. coli resistant to gentamicin, ciprofloxacin and third-generation cephalosporins was detected on 201 (96.6%), 191 (91.8%) and 77 (37.0%) of the farms, respectively. Of the 895 E. coli isolates, resistance to gentamicin, ciprofloxacin and third-generation cephalosporins was detected in 178 (19.9%), 291 (32.5%) and 29 (3.2%) of the isolates, respectively. Ciprofloxacin resistance was significantly associated with quinolone usage (OR = 2.26) and tetracycline usage (OR = 1.70). ESBL-producing E. coli were associated with farms containing fish ponds (OR = 4.82). Conclusions: Household and small farms showed frequent antimicrobial usage associated with a high prevalence of resistance to the most commonly used antimicrobials. Given the weak biocontainment, the high prevalence of resistant E. coli could represent a risk to the environment and to humans.

    Spatial planning for sustainable coastal shrimp production
    Joffre, O.M. ; Tri, Pham Dang ; Tran Thi Phung, H. ; Bosma, R.H. - \ 2015
    Aquaculture Asia XX (2015)1. - ISSN 0859-600X - p. 11 - 15.
    Combining participatory approaches and an agent-based model for better planning shrimp aquaculture
    Joffre, O.M. ; Bosma, R.H. ; Ligtenberg, A. ; Pham Dang Tri, V. ; Thi Phung Ha, T. ; Bregt, A.K. - \ 2015
    Agricultural Systems 141 (2015). - ISSN 0308-521X - p. 149 - 159.
    In the Mekong Delta coastal zone, decision makers must weigh trade-offs between sustaining the shrimp sector and thus ensuring economic development, while also promoting sustainable, environmentally friendly practices and planning for climate change adaptation. This study investigates future scenarios for development of shrimp aquaculture using a spatially explicit, agent-based model (ABM) simulating farmers' production system choices. A role playing game (RPG) with farmers was used to calibrate and validate the model. Four scenarios, representing different visions of aquaculture in the next 15 years, were elaborated with decision makers before discussing the different outputs of the model. Iterative consultation with farmers helped to fine-tune the model and identify key parameters and drivers in farmers' decision-making. The recursive process allowed us to construct a model that validly represents reality. Participants stated that use of the RPG improved their insight for planning. Results of the scenarios indicate that (i) intensification of production is unsustainable, (ii) market-based incentives are too limited to stimulate development of an integrated mangrove–shrimp production system and (iii) climate change will cause rapid decline of production in the absence of adaptation measures. RPG appeared to be a valuable method for formalizing local farmers' knowledge and integrating it into the planning approaches used by decision makers. The ABM, thus, can also be considered a medium or communication tool facilitating knowledge-sharing between farmers and decision makers.
    Vegetable production after flooded rice improves soil properties in the Red River Delta, Vietnam
    Everaarts, A.P. ; Neeteson, J.J. ; Pham Thi Thu, H. ; Struik, P.C. - \ 2015
    Pedosphere 25 (2015)1. - ISSN 1002-0160 - p. 130 - 139.
    sandy loam soil - physical-properties - farming systems - puddling depth - tropical asia - wheat system - constraints - opportunities - management - lowland
    Vegetable production in South East Asia often is in rotation with °ooded rice. The puddling of the soil with flooded rice production may result in unfavourable soil conditions for the subsequent production of dry land crops. To establish whether permanent vegetable production results in favourable soil conditions for vegetables, the effects of five different permanent vegetable production systems and a system of vegetable production in rotation with flooded rice on soil properties after flooded rice were studied in a 2-year field experiment. Bulk density at 0.05{0.10 m depth layer decreased with permanent vegetable production and vegetable production in rotation with flooded rice. The decrease in bulk density was in°uenced by the application of organic manure and rice husks, and especially by the number of crops cultivated, suggesting that frequency of soil tillage had a major effect on bulk density. Ploughing with buffalo traction after flooded rice, in combination with construction of raised beds, could reduce or totally eliminate negative effects of puddling on soil structure. Bulk density at 0.15{0.20 m soil depth was not influenced. Soil acidity decreased significantly in all systems. Soil organic carbon increased in all systems, but significant increase was only found in two permanent vegetable production systems. Available phosphorus (P) significantly increased in two permanent vegetable production systems, with a positively correlation to the amount of P applied. The significant decrease in bulk density and increase in pH (H2O), after only 2 years, showed that soil conditions after flooded rice could be improved in a short time under intensive vegetable production.
    Effect of supplementation diets of slipery fish level fat on performance, milk yield and milk composition of F1 (Landrace X Yorkshire) sows
    Pham, K.T. ; Nghia, D.H. ; Duc, N.L. ; Huynh Thi Thanh Thuy, ; Verstegen, M.W.A. - \ 2014
    Global Advanced Research Journal of Food Science and Technology 3 (2014)5. - ISSN 2315-5098 - p. 125 - 134.
    Twenty five F1 (Landrace x Yorkshire) sows parity of 2- 4 were used to determine the effect of catfish fat to late-pregnant and lactating sows on sow and their piglets’ performance. Sows were fed trial diets from 107 d of gestation until 21 d of lactation. Diets were: control without fish fat; 2% fish fat supplementation; 4% fish fat meal supplementation; 6 % fish fat meal supplementation; and 8 % 4% fish fat meal supplementation. The sow’s diet was made from the major ingredients including rice bran, corn meal, cassava meal and soy bean meal. Sows were fed 1.7 kg per day during gestation and 0.25 kg per piglet per day during lactation. Sows were were fed twice a day in the gestation and lactation period with diets containing 14.5 and 17.50 % of CP respectively. Calculated DE concentration in the diets was 13.0 –13.5 MJ per kg. Milk samples were obtained on d 3 and 20 of lactation. Milk from sows fed catfish fat increased n-3 fatty acids on d 3 and 20 of lactation. Results demonstrated that feeding catfish lard has significant effects on sow's milk yield, fatty acid profile and number and weight of weaned piglets.
    Advancing smallholder vegetable production systems in Vietnam and Tanzania
    Everaarts, A.P. ; Neeteson, J.J. ; Huong, Pham Thi Thu ; Putter, H. de; Abang, M. ; Struik, P.C. - \ 2014
    In: The food puzzle : pathways to securing food for all / Achterbosch, T.J., van Dorp, M., van Driel, W.F., Groot, J.J., van der Lee, J., Verhagen, A., Bezlepkina, I., Wageningen : Wageningen UR - ISBN 9789462571921 - p. 58 - 60.
    PermVeg: A model to design crop sequences for permanent vegetable production systems in the Red River Delta, Vietnam
    Pham Thi Thu Huong, Huong ; Everaarts, A.P. ; Berg, W. van den; Neeteson, J.J. ; Struik, P.C. - \ 2014
    Journal of Agronomy and Crop Science 200 (2014)4. - ISSN 0931-2250 - p. 302 - 316.
    soil - constraints - rotations - lowland
    The constraints in current vegetable production systems in the Red River Delta, Vietnam, in which vegetables are rotated with flooded rice, called for the design of alternative systems of permanent vegetable production. The practical model, PermVeg, was developed to generate vegetable crop sequences for permanent vegetable production, as based on a set of rules and restrictions. Permanent vegetable production systems were designed based on the following five scenarios: (i) increased profit, (ii) reduced labour requirement, (iii) decreased costs of pesticide use, (iv) improved crop biodiversity and (v) selected crops with low-perishable products. PermVeg showed that theoretically all selected crop sequences in the different alternative systems increased farmers’ income compared to the traditional system. The system with the highest profitability increased profit per hectare per day by a factor of three as compared to the traditional system. Labour requirement in days per hectare per day in a crop sequence also increased in all systems. Except for the system with low costs of pesticide use, permanent vegetable production systems had higher pesticide costs than the traditional, vegetable – flooded rice crop sequence. Given the model outcomes, permanent vegetable production systems can be an option to improve farmers’ income, to provide labour opportunities, and, in the case of the high crop biodiversity system, to contribute to the development of sustainable production systems. The PermVeg model can act as a practical tool to rapidly explore crop sequence options and to help farmers’ decision-making.
    Designing and testing permanent vegetable production systems for the Red River Delta, Vietnam
    Pham Thi Thu Huong, Huong - \ 2014
    Wageningen University. Promotor(en): Paul Struik, co-promotor(en): Arij Everaarts; Jacques Neeteson. - Wageningen : Wageningen University - ISBN 9789461738936 - 170
    groenteteelt - groenten - teeltsystemen - gewasbescherming - chemische bestrijding - rentabiliteit - arbeidsvereisten - vietnam - vegetable growing - vegetables - cropping systems - plant protection - chemical control - profitability - labour requirements - vietnam
    Check title to add to marked list
    << previous | next >>

    Show 20 50 100 records per page

     
    Please log in to use this service. Login as Wageningen University & Research user or guest user in upper right hand corner of this page.