Staff Publications

Staff Publications

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    '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.

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Teelt Gerbera in Balans : de invloed van lichtsom, etmaaltemperatuur en daglengte op productie, energiegebruik en plantbalans
Garcia Victoria, Nieves ; Gelder, Arie de; Kempkes, Frank ; Dings, Eugenie - \ 2017
Bleiswijk : Wageningen University & Research, BU Glastuinbouw (Rapport GTB 1417) - 102
glastuinbouw - kasgewassen - kassen - gerbera - energiegebruik - kooldioxide - kunstlicht - gewaskwaliteit - productie - greenhouse horticulture - greenhouse crops - greenhouses - energy consumption - carbon dioxide - artificial light - crop quality - production
“Gerbera: Growing in Balance” was a research project to support the reduction of energy and CO2 consumption in the cultivation of Gerbera. The varieties Pre-Semmy, Rich, Whisper and Suri were grown in three glasshouses with different treatments: “Cool Cultivation” (15°C temperature; 90 μmol light, day length 13 hour in winter); “Practice” (temperature depending on day light integral, 100 μmol/m2s light, day length 11.5 hours) and “Light Dependent” (temperature depending sharply on day light integral, 90 μmol/m2s light, day length 13 hours in winter). The day light integral was kept equal in all treatments, regardless the difference in light intensity and day length in the winter. For flower quality and energy use “Cool Cultivation” was the best treatment, but required the most kg / m² of CO2. Whisper and Suri produced more flowers / m2 in the treatment “Light Dependent” but flower weights were low. Pre-Semmy and Rich gave more flowers in the treatment “Practice”, but spalkes were weak in May and June. The 13 hour day length in winter was not detrimental to production or quality. Light sum, day length and daily temperature are the three buttons to control the plant balance for optimum production and quality. The project was Funded by the Program “Greenhouse as Energy Source” (Ministry of Economic Affairs and LTO Glaskracht) and the Knowledge Cooperative Gerbera.
The fatter the better : selecting microalgae cells for outdoor lipid production
Dominguez Teles, I. - \ 2016
Wageningen University. Promotor(en): Rene Wijffels, co-promotor(en): Maria Barbosa; Dorinde Kleinegris. - Wageningen : Wageningen University - ISBN 9789462578821 - 164
algae - chlorococcum - lipids - lipogenesis - fat - production - phenotypes - inoculum - diameter - cells - sorting - algen - chlorococcum - lipiden - lipogenese - vet - productie - fenotypen - entstof - diameter - cellen - sorteren

In chapter 1 we introduce microalgae, photosynthetic microorganisms with potential to replace commodities (such as food, feed, chemicals and fuels). Production costs are still high, reason why microalgae are still only economically feasible for niche markets. We suggest to borrow the concept of plant domestication to select industrial microalgae cells. Two approaches can be successfully used to domesticate microalgae: adaptive laboratory evolution (ALE) and fluorescence assisted cell sorting (FACS). ALE takes advantage of the natural adaptability of microorganisms to different environments, while FACS actually select cells with specific phenotypes. This thesis aimed to select cells of Chlorococcum littorale with improved phenotypes, assuming that these cells could establish new populations with increased industrial performance.

In Chapter 2 we wanted to know what happened during time to biomass and lipid productivities of Chlorococcum littorale repeatedly subjected to N-starvation. We tested 2 different cycles of N-starvation, short (6 days) and long (12 days). Short cycles didn’t affect lipid productivity, highlighting the potential of C. littorale to be produced in semi-continuous cultivation. Repeated cycles of N-starvation could have caused adaptations of the strain. Hence, we also discussed the implications of using repeated N-starvation for adaptive laboratory evolution (ALE) experiments. Chapter 3 introduces a method to detect and to select microalgae cells with increased lipid content. The method requires only the fluorescence dye Bodipy505/515 dissolved in ethanol, and the method was designed to maintain cellular viability so the cells could be used to produce new inoculum. In chapter 4 we evaluated a question that emerged while deciding which criteria to use to sort lipid-rich cells: does cellular size affects lipid productivity of C. littorale? We hypothesized that cells with different diameters have different division rates, which could affect lipid productivity. Therefore, we assessed the influence of cell diameter, as a sorting parameter, on both biomass and lipid productivity of Chlorococcum littorale (comparing populations before and after sorting, based on different diameters). Results showed that the size of vegetative cells doesn’t affect the lipid productivity of C. littorale. In chapter 5 we present a strategy to sort cells of C. littorale with increased TAG productivity using the method developed at chapter 3. Both the original and the sorted population with the highest lipid productivity (namely, S5) were compared under simulated Dutch summer conditions. The results confirmed our data from experiments done under continuous light: S5 showed a double TAG productivity. Our results showed also that the selected phenotype was stable (1.5 year after sorting) and with potential to be used under industrial conditions. In chapter 6 we extrapolated our results (indoor and outdoor) to other climate conditions. We ran simulations changing the light conditions to four different locations worldwide (the Netherlands, Norway, Brazil and Spain) to estimate both biomass and TAG productivities. Results indicated that biomass yields were reduced at locations with higher light intensities (Brazil/Spain) when compared with locations with lower light intensities (Norway/Netherlands). Hence, the choice of location should not be based on light intensity, but on how stable irradiation is. Chapter 7 is the general discussion of the thesis, demonstrating that both ALE and FACS are effective approaches to select industrial microalgae cells. We also present our view on how ALE and FACS could further improve microalgae strains for industry.

Grondstofefficiëntie in de zuivel-, varkensvlees-, aardappel- en suikerketen
Baltussen, W.H.M. ; Dolman, M.A. ; Hoste, R. ; Janssens, S.R.M. ; Reijs, J.W. ; Smit, A.B. - \ 2016
LEI Wageningen UR (Nota / LEI Wageningen UR 2016-013) - 85 p.
agro-industriële ketens - efficiëntie - duurzaamheid (sustainability) - melk - varkensvlees - aardappelen - suiker - productie - nederland - agro-industrial chains - efficiency - sustainability - milk - pigmeat - potatoes - sugar - production - netherlands
In opdracht van het ministerie van Economische Zaken en Topsector Agri & Food heeft LEIWageningen UR de state-of-the-art in kaart gebracht op het gebied van de duurzaamheidsprestatiesvoor vier belangrijke grondstoffen van de aardappel-, suiker-, varkensvlees- en zuivelketen. De viergrondstoffen zijn: land, water, energie en fosfaat. De focus in dit rapport ligt op de kansen enuitdagingen die er zijn op het gebied van efficiënter grondstofgebruik.
Metabolic engineering of Escherichia coli for itaconate production
Vuoristo, K.S. - \ 2016
Wageningen University. Promotor(en): Gerrit Eggink; Johan Sanders, co-promotor(en): Ruud Weusthuis. - Wageningen : Wageningen University - ISBN 9789462576001 - 162
fermentation - escherichia coli - aspergillus niger - biobased chemistry - bioengineering - acids - organic acids - glutamates - tca - production - chemicals - fermentatie - escherichia coli - aspergillus niger - chemie op basis van biologische grondstoffen - bioengineering - zuren - organische zuren - glutamaten - tca - productie - chemicaliën

Interest in sustainable development together with limited amounts of fossil resources have increased the demand for production of chemicals and fuels from renewable resources. The market potential for bio-based products is growing and a transition from petrochemicals to biomass-based chemicals is ongoing. Itaconic acid is a C5-dicarboxylic acid which can be produced by microbial conversion processes. It can be easily polymerized and is an appealing building block for the chemical industry with many potential applications. However, biobased chemicals have to compete with their petrochemical counterparts, and yield and productivity of the microbial processes are therefore of the utmost importance. Traditionally itaconic acid is produced using the ascomycete Aspergillus terreus. This process is not competitive with petrochemical processes due to high production costs caused by low yields, and difficult and expensive product recovery. Maximizing product yield is important to lower production costs. This thesis looked at ways to reach theoretical maximum yield in a recombinant production host, Escherichia coli.

Chapter 2 describes the construction of an itaconate biosynthesis pathway in E. coli. The key enzyme of microbial itaconate production is cis-Aconitate decarboxylase (CadA) that converts the citric acid cycle intermediate cis-aconitate into itaconate. We focused on optimizing heterologous expression of cadA from Aspergillus terreus in E. coli. Initially this resulted in low CadA activities and production of trace amounts of itaconate. CadA was primarily present as inclusion bodies, explaining the low activity. The activity was significantly improved by using lower cultivation temperatures and mineral medium and this resulted in enhanced itaconate titres. The itaconate titre was further increased in aerobic bioreactor cultures by introducing citrate synthase and aconitase from Corynebacterium glutamicum and by deleting genes encoding phosphate acetyltransferase and lactate dehydrogenase. The maximum itaconate yield from glucose obtained in this study was only 0.09 mol/mol, due to high flux of carbon to by-products such as acetate and pyruvate. Pyruvate is a precursor molecule for itaconate biosynthesis and its accumulation suggested that the activity of CadA might be one of the rate limiting steps. It was concluded that further optimization of cadA expression, and reduction of acetate formation should be achieved to obtain higher itaconate yield.

As sufficient cis-aconitate decarboxylase activity is crucial for itaconate production, in chapter 3 ways to increase the activity of CadA were investigated. A recently characterized cis-aconitate decarboxylase of mammalian origin was therefore expressed in E.coli. The novel cis-aconitate decarboxylase from Mus musculus encoded by immunoresponsive gene 1 (irg1) produced comparable amounts of itaconate as CadA from A. terreus. In addition, the effects of codon optimization and harmonization on enzymatic activities of heterologously expressed cadA and irg1 were studied. Codon harmonization increased the activity of CadA in cell free extracts, but this did not result in higher itaconate production in bioreactor cultures. This suggests that other factors such as itaconate transport may limit the production.

In chapter 4, proof of principle for an anaerobic fermentation process for the production of itaconic acid was obtained by using the mixed acid fermentation pathway of E. coli. Itaconic acid production was redox balanced by co-producing succinate or ethanol with H2 and CO2. Expression of cadA together with citrate synthase (gltA) and aconitase (acnA) from Corynebacterium glutamicum resulted in 0.66 mM (1.2 % Cmol) itaconate under anaerobic conditions. Unexpectedly, strains started to produce significant amounts of glutamate when the itaconate pathway was introduced. As glutamate production depends on the availability of nitrogen in the medium, a nitrogen-limited medium was tested to diminish glutamate production. This enhanced the production of itaconate to up to 2.9 mM (5.4 % C mol %). Here, anaerobic production of itaconate from glucose was reported for the first time. The observed itaconate yields and productivities were still modest. Eliminating the pathways to major by-products like glutamate, succinate, and acetate, and enhancing the pathway between pyruvate and itaconate is crucial to obtain a cost-competitive anaerobic itaconic acid process production.

To investigate how itaconate production can be improved, the insights from the previous chapters together with existing scientific literature were combined with our pathway design proposals in chapter 5. The tricarboxylic acid (TCA) cycle is an important source of precursors for biobased chemicals. The opinion article takes a closer look at the metabolic engineering of TCA cycle for the production of chemicals high yield. For most TCA cycle products the maximum pathway yield is much lower than the theoretical maximum yield. For succinate, this was solved by creating two pathways to the product, using both branches of the TCA cycle, connected by the glyoxylate shunt. A similar solution cannot be applied directly for production of compounds from the oxidative branch of the TCA cycle because irreversible reactions are involved: the conversion of acetyl-CoA and glyoxylate to malate in the glyoxylate shunt and the conversion of 2-oxoglutarate into succinyl-CoA in the TCA cycle. This way, the pathway yield for products originating from the oxidative TCA cycle branch such as citrate, itaconate and L-glutamate becomes identical to the theoretical maximum. Future research should focus on implementing these solutions in suitable production hosts, and increasing the ATP yield of the production pathways. This will minimize the oxygen requirement of the process, or even allow for anaerobic operation, and should lead to reduced operational costs and maximal product yields.

In chapter 6 the implications of the overall results of this thesis for the current research status of itaconate production are presented. Solutions to optimize itaconate production strains and production process were proposed.

Logistics network design & control : managing product quality in a blooming sector
Keizer, M. de - \ 2015
Wageningen University. Promotor(en): Jack van der Vorst, co-promotor(en): Jacqueline Bloemhof-Ruwaard; Rene Haijema. - Wageningen : Wageningen University - ISBN 9789462576025 - 239
logistiek - netwerkanalyse - sierteelt - kwaliteitszorg - kwaliteit - productie - tuinbouw - verse producten - voedselproducten - simulatiemodellen - simulatie - logistics - network analysis - ornamental horticulture - quality management - quality - production - horticulture - fresh products - food products - simulation models - simulation
Lichtspectrum als middel voor energiezuinige rozenteelt : praktijkproef bij Van der Arend Roses
Garcia Victoria, N. ; Pot, S. - \ 2015
Bleiswijk : Wageningen UR Glastuinbouw (Rapport GTB 1368) - 68
teelt onder bescherming - glastuinbouw - rozen - kunstlicht - led lampen - lichtsterkte - productie - kwaliteit - energiebesparing - energy economics - protected cultivation - greenhouse horticulture - roses - artificial light - led lamps - light intensity - production - quality - energy saving
During the winter 2014-2015 a research was conducted at a commercial rose nursery to learn more about the influence of a special lamp light spectrum on the production and quality of the rose Avalanche. A “hybrid” lighting system was installed with 103 µmol /m2s PAR from High Pressure Sodium and from Valoya LED lamp G1 in two different intensities: 57 or 103 µmol /m2s PAR. Compared with the conventional installation of the company (191 micromol SON-T), the spectrum of the hybrid installation allowed, depending on the intensity of the added LED, a 7.2% to 9% higher light use efficiency (LUE) by the crop. This offers possibilities for energy saving, but therefore the energy efficiency of the lamps used (Valoya G1) needs to increase to an output of 1.7 µmol PAR per watt electric. Valoya is already working on this improvement. The performed plant measurements (SPAD, bud temperature, photosynthesis, leaf area, etc.) do not contribute to explain this positive effect. More research about the effects of light colour on the rose production is needed. Remaining questions are if other rose varieties react the same to the combined spectrum, if the crop can grow more compact in winter when there is more blue in the spectrum, and if a larger proportion of far-red light could make the flowers even heavier, with a larger flower bud. The research was funded by the program “Greenhouse as Energy Source” (Ministry of Economy and the Horticultural Product Board) and Valoya.
Assessment of strategies for value chains using an extended Structure-Conduct-Performance (SCP) framework: an application to the honey business in Brazil
Santana De Figueiredo Junior, H. - \ 2015
Wageningen University. Promotor(en): Alfons Oude Lansink, co-promotor(en): Miranda Meuwissen. - Wageningen : Wageningen University - ISBN 9789462575516 - 152
bedrijfseconomie - honing - productie - bedrijven - brazilië - business economics - honey - production - businesses - brazil

Keywords: Strategy evaluation, global networks, supply chains, policy Delphi, conjoint analysis, economic development, competitiveness, beekeeping, interventions, uncertainty, upgrading.

Competition for the end-customer nowadays takes place more among networks of firms than among individual firms. The analysis of competing firms, thus, has to go beyond the limits of each firm to incorporate the analysis of the entire chain(s) in which the firms participate. An approach is lacking to integrate the relations between strategy and structural issues, such as regulations, demand trends and concentration of clients/suppliers, and economic performance in terms of the contribution to local development. The general objective of this research was to make ex-post and ex-ante assessments of strategies for honey value chains in Brazil. The honey chain was chosen because of the importance of honey production and trade to Brazil, which was among the top ten world honey exporters in terms of volume. This thesis extended the Structure-Conduct-Performance (SCP) framework to value chains, identifying categories of structure, conduct and performance for value chain streams (segment of a value chain in a territory) and providing an integrated approach to explore possible interactions among those categories. The empirical applications of this research used this value chain SCP framework and focused on three honey value chain streams, located in the northeast of Brazil, all in top producing areas: two in Ceará State (Limoeiro do Norte and Santana do Cariri) and one in Piauí State (Picos). First, likely successful strategies of those value chain streams to their performance were identified for the 2007-2011 period, in a multi-case study. Then, the contributions of individual strategies of those streams to their performance were quantitatively assessed, also for the 2007-2011 period, using conjoint analysis. Finally, using adaptive conjoint analysis, promising strategies in terms of their contribution to chain competitiveness and local development were identified, under different scenarios. The results of this thesis reveal that the value chain SCP framework allows for ex-ante and ex-post integrated assessments of strategies for a segment of a value chain in a territory. The results also show that the relative importance of strategies to enhance performance of the studied honey value chain streams in Brazil depends on industry structure and varies among performance goals. In addition, the alignment of the value chain stream strategies towards a certain performance goal improves the likelihood of success of the implementation task. Moreover, the most commonly applied upgrading typologies do not cover all the strategy choices to value chain streams.

Certifications, child labour and livelihood strategies: an analysis of cocoa production in Ghana
Owusu-Amankwah, R. - \ 2015
Wageningen University. Promotor(en): Han Wiskerke; Guido Ruivenkamp, co-promotor(en): Joost Jongerden. - Wageningen : Wageningen University - ISBN 9789462574915 - 348
cacao - productie - landbouw bedrijven in het klein - gemeenschappen - kinderarbeid - strategieën voor levensonderhoud - certificering - agrarische productiesystemen - ghana - cocoa - production - peasant farming - communities - child labour - livelihood strategies - certification - agricultural production systems - ghana


There have been various innovative initiatives by global and local actors in response to pressure on cocoa value-chain actors to free cocoa production from child labour (CL) and especially the worst forms of child labour (WFCL) and also to improve the livelihoods of farm families. Analyses of the implementation, implications and the appropriateness of these initiatives in driving change in the cocoa supply chain and improving the labour and income conditions in cocoa farms are limited, however. This study examines initiatives being led by the key actors in the value chain – the governmental initiative of a community-based child labour monitoring (CCLM) system (CCLMS), that led by business actors of third party voluntary cocoa certification (TPVCC), and farmers’ own way of diversifying income – in order to understand current developments in the cocoa value-chain and analyse the dynamics between the local and global actors and the effect of these dynamics for the reorganisation of the cocoa production system in Ghana.

This thesis employs an interdisciplinary perspective and combines innovation theory with livelihood, social perspectives and other social science tools to empirically investigate the initiatives as they operate at micro-, meso- and macro-levels so as to ascertain their implications for farmers’ livelihoods and children’s social situations. It also reflects scholarly interest in understanding how global-level development interacts with and affects local-level development, and how globalisation shapes and mediates local influences within the cocoa production system.

Firstly, the CCLMS study (Chapter 3) reveals three kinds of benefits to children: an expanded social network, a reduction in their participation in hazardous work and an improvement in school attendance. The findings show that absenteeism on the part of the pupils in a community with a CCLM intervention is approximately half that of two communities without intervention. In addition, it is observed that although children are involved in hazardous and non-hazardous activities in all the three communities involved in the study, the extent of their involvement in hazardous activities is higher in the communities without intervention.

Secondly, third party certification (TPC) formulated by the business actors is a key innovation in the cocoa production system of Ghana. The study presented in Chapter 4 shows the potential of TPVCC to mobilise financial, human and social capitals to address gaps and

dysfunctions and create a win-win situation for all the actors of the value chain. However, sector-wide standards that address sector specific needs taking into consideration the views of chain actors, especially farmers and their socio-cultural context will enhance compliance. This is because global or international standards cannot be imposed but are analysed, contested and adapted by farmers to suit on-the-ground practices. The study also shows the potential of TPVCC to address CL and livelihood issues, but these will yield better results if it is implemented in enhanced socio-economic conditions. Regardless of these positives, the net benefit of certification is unclear due to the difficulty in conducting proper cost-benefit analyses in the absence of proper documentation of farmer-level costs and other factors.

Thirdly, the findings show that about 70% of farmers are diversifying into other (non-cocoa) farm and non-farm activities using largely indigenous resources, but on a small scale and at subsistence level. This condition means that the goal of farmers to supplement cocoa income and reduce risk is not achieved throughsuch a level of diversification. There is some indication of increasing importance of income and resources from non-farm activities, but income from cocoa continues to determine household income as well as the demand for non- farm goods and investment in the non-farm sector. This study also finds that children are involved in both farm and non-farm activities, which can be classified as hazardous and non- hazardous. Farmers, especially caretakers, producing at subsistence level are likely to use their children to supplement labour needs. Some policy recommendations are made in the areas of economic incentives and multi-stakeholder collaboration to stimulate the sector towards sustainability.

Greening production and consumption: the case of the appliance and dairy industries in Thailand
Thongplew, N. - \ 2015
Wageningen University. Promotor(en): Gert Spaargaren, co-promotor(en): Kris van Koppen. - Wageningen : Wageningen University - ISBN 9789462574397 - 176
duurzaamheid (sustainability) - consumptie - productie - consumenten - milieubeleid - zuivelindustrie - toestellen - computerwetenschappen - engineering - thailand - sustainability - consumption - production - consumers - environmental policy - dairy industry - appliances - computer sciences - engineering - thailand


Natapol Thongplew

Thesis title: Greening production and consumption: The case of the appliance and dairy industries in Thailand

This research looked into the greening of the appliance and dairy industries in globalizing Thailand from a product chain perspective. It studied roles and strategies of appliance and dairy companies in greening consumption with an explicit involvement of consumers. This research finds that appliance and diary have increasingly attempted to engage Thai consumers in buying and using more sustainable products. To do so, companies employ different consumer-oriented strategies, including providing environmental information; however, they do not yet have a full-fledged consumer-oriented strategy to activate and engage (silent green) consumers. The study summarizes that appliance and diary companies in Thailand can advance their consumer-oriented strategies for better engaging Thai consumers (with green products and green markets) by acknowledging the role of consumers as citizens, recognizing emerging sustainable practices and lifestyles of citizens, and organizing consumer groups.

Workshop gewasgezondheid en vruchtkwaliteit bij vochtig telen : kennisuitwisseling teeltadviseurs
Gelder, Arie de - \ 2015
horticulture - greenhouse horticulture - cucumis - rosa - crop quality - workshops (programs) - moisture content - mycosphaerella - radiation - evaporation - temperature - lighting - production
Juiste keuzes voor een maximale Vem-opbrengst : stappenplan maïsteelt deel 1
Groten, J.A.M. - \ 2015
Grondig : vakblad voor de cumelasector, specialisten in groen, grond en infra (2015)1. - ISSN 2210-3260 - p. 32 - 33.
akkerbouw - maïs - teeltsystemen - opbrengst - productie - productiefactoren - rassenkeuze (gewassen) - vroegheid - bemesting - drijfmest - kunstmeststoffen - arable farming - maize - cropping systems - outturn - production - factors of production - choice of varieties - earliness - fertilizer application - slurries - fertilizers
Vroeger was maïs telen vrij eenvoudig: (veel) mest uitrijden, ploegen met een vorenpakker, zaaien, onkruid bestrijden en oogsten. Anno 2015 is de maïsteelt een hele puzzel. Om dit jaar, maar ook in de toekomst een hoge Vem-opbrengst te kunnen realiseren, moeten de juiste keuzes worden gemaakt. In twee artikelen belichten we de juiste stappen voor een topopbrengst
Strategies to support the greenhouse horticulture sector in Ghana
Elings, A. ; Saavedra, Y. ; Nkansah, G.O. - \ 2015
Wageningen : Wageningen UR (Report GTB 1353) - 52
glastuinbouw - ghana - groenteteelt - agrarische bedrijfsvoering - productie - kwaliteit na de oogst - kastechniek - zonne-energie - mechanisatie - geografische rassen - rassen (planten) - geïntegreerde bestrijding - greenhouse horticulture - vegetable growing - farm management - production - postharvest quality - greenhouse technology - solar energy - mechanization - geographical races - varieties - integrated control
Protected cultivation in Ghana is relatively small, though public and private interest is rapidly increasing. This report presents a quick scan of the sector, with a focus on business opportunities. From a value chain perspective, inadequate access to inputs, low production levels, poor storage facilities and low product quality are the main limitations. Key factors to improve the situation are: a) a country-wide seed supply system that makes available high quality cultivars, b) the availability of biological control agents, c) a greenhouse design that is suitable for the local, hot climate, d) a healthy growing medium, and e) well-trained management and staff. Business opportunities are: a) greenhouses adapted to the local climate, greenhouse equipment, solar energy, sensors and data loggers, and a local industry fabricating and maintaining goods, b) variety trials and hybrid varieties, and c) integrated pest management and biological control.
DaglichtKas maakt duurzame ambities meer dan waar
Zwart, H.F. de - \ 2014
Kas techniek (2014)9. - p. 12 - 15.
glastuinbouw - kastechniek - kassen - beglazing - daglicht - energiegebruik - duurzame energie - productie - monitoring - greenhouse horticulture - greenhouse technology - greenhouses - glazing - daylight - energy consumption - sustainable energy - production
Vlak voor de zomer startte Ter Laak Orchids uit Wateringen met telen in de gloednieuwe DaglichtKas. Ruim een half jaar later blikken we terug op het ontstaan van dit duurzame kasconcept en kijken we naar de resultaten tot nu toe. Duidelijk is in ieder geval dat de eerste ervaringen de verwachting overtreffen.
Networking, social capital and gender roles in the cotton system in Benin
Maboudou Alidou, G. - \ 2014
Wageningen University. Promotor(en): Anke Niehof, co-promotor(en): Jarl Kampen. - Wageningen : Wageningen University - ISBN 9789462570634 - 187
katoen - productie - boeren - landbouwhuishoudens - boerenorganisaties - sociaal kapitaal - netwerken - geslacht (gender) - strategieën voor levensonderhoud - benin - cotton - production - farmers - agricultural households - farmers' associations - social capital - networks - gender - livelihood strategies - benin

Cotton production in Benin, West Africa, is intertwined with colonialism, which contributed to the trans­formation of the crop’s production system from traditional to modern. Through­out the years, the importance of the crop for the stakeholders varied. The last decades have witnessed a growing interest in cotton of farmers, businessmen, and the State. From having a marginal status during the seventies and the first half of the eighties, cotton grew in importance during the nineties, both in terms of area covered and income generated, averaging 37 percent of the total cultivated area in the country. Thus, cotton has a critical cash function and plays a key role in Benin’s economic growth, accounting for an important share in the State’s revenues and farm house­holds incomes. Indeed, the share of cotton exports represented 75 percent of the country’s total agricultural exports during the 2000s, and the crop provided up to 80 percent of rural households incomes in the North. Though cotton is grown throughout the country, its production was always concentrated in the North, where it is embedded in a farming system formerly dominated by food crops. Hence, cotton transformed subsistence farming into semi-subsistence farming.

The central position of the crop in the country’s economy, which loomed large at the beginning of the 1990s, led to agricultural and economic policies being greatly influenced by the crop for decades. The Structural Adjustment Program of the early 1990s prescribed the liberalisation of the cotton sector, which had huge effects on the sector. This resulted in an increased importance of cotton farmer organisations that elapsed into the first ever hierarchical network in the country, and the crop being put at the forefront of agricultural development programs. Enduring benefits for farmers, farming communities, private actors, and the State were derived from that evolution. This gained cotton the status of ‘white gold’. The institutional dynamics that followed in the wake of liberalisation and their corollary of actors’ interactions generated never-ending conflicts of various kinds, particularly within the cotton farmers’ networks. These resulted in atomised networks. As a consequence, the benefits attached to cotton then started to wane and cotton production became a dilemma for farmers, as reflected in a steep decline of cotton production.

This thesis aims at understanding the dynamic interactions between the economic activity of cotton production and the structure of social relations from community to household and individual level. It addresses the question of how farmers’ agency affected their organisations, the cotton system, and the collective action that evolved around the crop. The research was aligned along three main axes: the emergence of breakaway networks, the decline of social cohesion and the squeeze of collective action, and the livelihoods reconstruction after the demise of cotton production. The main theoretical perspectives underlying the conceptual framework were an actor-oriented approach, actor-network theory, livelihood theory, and a gender perspective.

The research is based on fieldwork carried out in four provinces in the North of Benin from January 2009 to April 2011. Benin is a country whose employment capacity and economic growth heavily rely on the agricultural sector, in which cotton is a dominant factor. This is still the case for rural areas in the North, where rural households have been heavily dependent on cotton as a critical cash crop for poverty alleviation. Northern Benin supplies more than 75 percent of the cotton yearly produced in the country, thanks to the favourable agro-ecological conditions prevailing there, and because there is less population pressure than in the southern part. The exploratory phase of the research covered four provinces: Borgou, Alibori, Atacora and Donga. Since the provinces of Borgou and Alibori host the heart of the cotton belt, subsequent data collection progressively focussed on these two provinces.

The research adopted a mixed-methods design, applying quantitative and qualitative methods of data collection. A survey was combined with focus-group discussions, in-depth interviews and the life history method, to unveil the dynamic interactions between social actors and their interactions with the material and technical elements of the cotton system. The life history method was used to document the experience of women leaders that had made them exceptions to the rule among women cotton farmers. Apart from cotton farmers and their leaders, other targets groups of the research, like inputs suppliers and executives of cotton bodies, often had to be found beyond the two provinces in other parts of the country. The research covered eight cotton networks in ten villages in the four provinces. Survey interviews and in-depth interviews were conducted with 148 heads of cotton farming households, men as well as women.

About 80 percent of the farmers in the sample were in their 40s or 50s, and more than half of them had no formal education. Educated women represented only 17 percent of their category, suggesting that male cotton farmers are significantly more educated than their female counterparts. The average household size was 16, with about 11 workers in male adult equivalents. While agriculture is the main occupation and often the only source of income in the area, women turned out to rely less on agricultural incomes than men.

With regard to networking, the process of atomisation resulted in about 20 percent of stayers in remnant networks, 51 percent of joiners of operating networks, and about 28 percent of creators of new networks. It was found that more than three quarters of cotton farmers broke away from their original network at least once during their cotton cropping career, and that creators of new networks were more likely to be leaders than stayers or joiners. The results further tell us that more than one in two cotton farmers (ever) had a leadership position. A significant association was found between these three categories of farmers and leadership status. Finally, a greater stock of social capital was correlated with the ability of leading cotton networks.

The research indicates that the liberalisation of an agricultural value-chain can be harmful rather than beneficial when the State fails to play a coherent role during the shift from State monopoly to private interest. Cotton proved to be the lifeline for farmer organisations, and drove collective action in rural areas from the important resources it generated. However, the decline of trust within the networks in conjunction with poor management of cotton resources led to a reversed dynamic that tore networks apart, which resulted in their atomisation. Social relations deteriorated when the financial stakes became higher. As attested by the way the process of network atomisation evolved, cooperation within large groups requires legal sanctions to be sustainable. The qualitative results showed that the process of atomisation was nurtured by ties of friendship, kinship, residence and ethnicity at the start, after which networks extended to include other areas and more general member­­ship. From the survey results it can be inferred that push and pull factors interacted to influence the process of cotton network atomisation. The most influential of these factors were, on the one hand, mismanagement of network resources and manipulation of farmers by outsiders, and, on the other hand, trust in board members, hope for board positions, the expectation of profit, and support from public officials and ethnic or religious connections.

The research further demonstrates that gender myths and stereotypes obstruct women's active involvement in managing organisations, in spite of their key position in the cotton production system at household level. Women were found 21 times less likely to be a leader than men in cotton organisations, and their presence on boards hardly empowered them because they spend their energy struggling to meet practical needs. Women’s admission to cotton boards appears to be instrumental for men and hides men's real motives, judging by the way male board members tend to restrict the power of their female colleagues. However, men are inclined to give more freedom to women when they find their activities benefitting themselves, as was revealed by the data on livelihood adaptation strategies.

The research clearly ascertains that farmers are more rational than often assumed and that they grow a crop as long as it is a source of livelihood and food security. Despite its current low to negative returns, cotton remains part of the livelihood diversification strategies of households because cotton production gives access to fertilisers which can then be used for food crops. However, relying on one source of income puts the livelihood system of rural households at risk. Faced with the cotton problems, households diversified their sources of income, first and primarily on-farm with food crops increasingly gaining a cash function. Additionally, they would deploy beyond-farm alter­native strategies, including migration of youth. It was also found that the decline of cotton production proved to result in more freedom for women. Because of their multiple extra-domestic activities, women are less vulnerable than men when it comes to coping with livelihood shortages. Their contribution to the provision for house­hold needs increased during the decline of cotton production and the ensuing income shortages compared to that of men. The livelihood adaptation strategies showed the decision making about income diversification to move from the centre of the household to its periphery.

Tussensegment voor varkens- en pluimveevlees : een krachtenveldanalyse in Duitsland en Europa
Oosterkamp, E.B. ; Wielen, P. van der; Vogelzang, T.A. - \ 2013
Den Haag : LEI, onderdeel van Wageningen UR (Rapport / LEI : Onderzoeksveld Sector & ondernemerschap ) - ISBN 9789086156412 - 53
varkensvlees - pluimveevlees - export - markten - productie - marketing - dierenwelzijn - houding van consumenten - vleeswaren - nederland - duitsland - pigmeat - poultry meat - exports - markets - production - animal welfare - consumer attitudes - meat products - netherlands - germany
Sinds 2011 zijn Duitse ngo's, kennisinstellingen en marktpartijen stevig in beweging gekomen om het tussensegmentvlees in de markt te zetten. Het gaat hierbij vooral om de productie en vermarkting van diervriendelijker geproduceerd vlees. Op dit moment zijn vooral varkensvlees en kippenvleesproducten in de markt geïntroduceerd. Er lijkt in Duitsland een toenemende vraag te zijn naar vleesproducten uit het tussensegment. Door een toenemend consumentenbewustzijn op het gebied van dierenwelzijn neemt de vraag naar diervriendelijker geproduceerd vlees in Duitsland toe. In potentie liggen er dus kansen voor de afzet van Nederlands tussensegmentvlees in Duitsland. Exporteurs naar de Duitse markt moeten zeker rekening houden met diergerelateerde welzijnsindicatoren. Exporteurs die elk afbreukrisico willen vermijden wordt aanbevolen aan te sluiten bij de nieuwe standaard en het label dat door de Deutscher Tierschutzbund is ontwikkeld.
Synthesis of galacto-oligosaccharides with ß-galactosidases
Warmerdam, A. - \ 2013
Wageningen University. Promotor(en): Remko Boom, co-promotor(en): Anja Janssen. - S.l. : s.n. - ISBN 9789461735621 - 171
oligosacchariden - bèta-galactosidase - productie - synthese - immobilisatie - bioreactoren - lactose - oligosaccharides - beta-galactosidase - production - synthesis - immobilization - bioreactors - lactose

Galacto-oligosaccharides (GOS) are generally enzymatically synthesized with β-galactosidases. GOS are of interest because of their prebiotic effects on human health. They are mainly applied in infant nutrition, because of their resemblance to human milk oligosaccharides, but they are also applied in e.g. dairy products and beverages.

β-Galactosidases synthesize GOS from lactose through transgalactosylation: instead of only using water as acceptor (as in hydrolysis), they can use carbohydrates as acceptor. In this way, GOS with a degree of polymerization up to ten can be formed. The ratio of hydrolysis over transgalactosylation depends on the substrate concentration, temperature, and the source of the enzyme.

A β-galactosidase preparation from Bacillus circulans, called Biolacta N5, is known to produce high GOS yields compared to enzymes from other sources. The aim of this thesis was to obtain more insight on the mechanism of GOS production with Biolacta N5 and to investigate how the GOS production process can be optimized.

Biolacta N5 consists of four β-galactosidase isoforms, β-gal-A, β-gal-B, β-gal-C, and β-gal-D, which were purified and characterized in chapter 2. At low substrate concentrations, these isoforms differ in hydrolysis and transgalactosylation activity. β-Gal-D seems the best isoform for GOS production, followed by β-gal-C and β-gal-B, and β-gal-A showed the least GOS formation. By studying the thermodynamics of lactose conversion with isothermal titration calorimetry (ITC), the differences in behavior were confirmed, although the interpretation of the results of ITC was quite difficult dealing with a complex mixture of reactions. In contrast to the selectivity at low substrate concentrations, the selectivity of the isoforms hardly differed at high lactose concentrations. These conditions are usually used for industrial GOS production. Only β-gal-A produced slightly more galactose. The initial GOS formation rates indicated that β-gal-A and β-gal-B are the best isoforms for GOS production.

In chapter 3, the effect of high concentrations was further studied on the behavior of the complete Biolacta N5 preparation. High concentrations of reacting and non-reacting carbohydrates were added to the oNPG activity assay with Biolacta N5. Small carbohydrates were found to act as acceptor in the reaction, which resulted in an increased reaction rate. The rate of the limiting step of the reaction, i.e. the binding of the galactose residue with the acceptor, is increased, and therewith the release of the product is faster. At the same time, the additives cause molecular crowding, which results in a higher affinity between the enzyme and the substrate.

In chapter 4, a kinetic model was developed to quantify the effects of lactose, glucose, galactose, and oligosaccharides on the oNPG converting activity of the β-galactosidases from B.circulans, Aspergillus oryzae and Kluyveromyces lactis. Using multiple substrates simultaneously yields more information than using only lactose or oNPG, because of the competition between the substrates. Three main differences were found that explain why Biolacta N5 produces higher GOS yields than other β-galactosidases: (i) it had a higher reaction rate constant of using lactose or oligosaccharides as substrate relative to water as acceptor (so it had a very low relative hydrolysis rate); and (ii) it also had a high reaction rate with galactose as acceptor, whereas (iii) the other two enzymes are strongly inhibited by galactose. The reaction rate constants indicate that β-gal-A is the most active isoforms in GOS production; however, also its hydrolysis rate is highest. Many of the rate constants increase with increasing molecular weight of the isoforms.

Chapter 5 reports on the stability of Biolacta N5 at various temperatures in buffer, and in systems with initially 5.0 and 30% (w/w) lactose. Samples were taken in time and analyzed for oNPG converting activity. The oNPG converting activity was corrected for the presence of lactose, glucose, galactose, and oligosaccharides with the mechanistic model from chapter 4. The stability, expressed with the half-life time, of the enzyme was found to strongly increase with initial lactose concentrations. At high substrate concentration, higher temperatures can be used for GOS production than was presumed feasible based on stability measurements in diluted solutions.

Biolacta N5 is still active after one batch run of GOS production, but in a batch process the enzyme is wasted after the reaction. For this reason, the use of immobilized enzyme in a continuous packed bed reactor (PBR) was investigated in terms of productivity in chapter 6. The carbohydrate composition of the product in both systems was comparable. The half-life time of the immobilized enzyme at a lactose concentration of 33% (w/w) and 50ºC was approximately 90 days. The enzymatic productivity using immobilized enzyme in a PBR may be six times higher than that using free enzyme in a batch reactor. When striving for an equal volumetric productivity of both systems, the volume of a PBR can be much smaller than that of a batch reactor, depending on the enzyme dosage and running time of the one batch.

Chapter 7 discusses various alternatives for process optimization. One option for a higher GOS productivity is to use an enzyme preparation that contains only β-gal-A and β-gal-B. A somewhat higher oligosaccharide yield can be obtained when initially using a mixture of lactose with a better acceptor molecule. This results in a changed oligosaccharide composition and less lactose in the final product. The sustainability of GOS production in a PBR with immobilized enzyme and 33% (w/w) lactose seems to be similar in terms of exergy to that in a batch reactor with free enzyme and 60% (w/w) lactose.

Economic and agronomic analysis of the seed potato supply chain in Ethiopia
Tufa, A.H. - \ 2013
Wageningen University. Promotor(en): Alfons Oude Lansink; Paul Struik, co-promotor(en): Miranda Meuwissen; Willemien Lommen. - S.l. : s.n. - ISBN 9789461735430 - 170
pootaardappelen - zaadkwaliteit - verbetering - voedselketens - ketenmanagement - houding van boeren - voedselzekerheid - productie - solanum tuberosum - aardappelen - economische analyse - prestatieniveau - ethiopië - seed potatoes - seed quality - improvement - food chains - supply chain management - farmers' attitudes - food security - production - solanum tuberosum - potatoes - economic analysis - performance - ethiopia
Production and productivity of potato in Ethiopia are very low because of poor quality seed tubers and unavailability of seed tubers of improved varieties. These poor quality seed tubers and unavailability of seed tubers of improved varieties are caused by economic and agronomic factors. This thesis deals with economic and agronomic aspects that affect quality and availability of seed potatoes in Ethiopia. It encompasses analysis of strengths and weaknesses of seed potato systems currently operating in Ethiopia, elicitation of farmers’ opinions on management attributes that they believed to affect yield and quality of potato, cost-effective seed potato production plans for farmers in Ethiopia, and analysis of performance of existing and potential seed potato supply chains. The results of this thesis indicate that seed quality and availability can be improved by improving economic and agronomic aspects of the seed systems in general and seed supply chains in particular.
Intellectual property rights, international trade and plant breeding
Eaton, D.J.F. - \ 2013
Wageningen University. Promotor(en): Erwin Bulte, co-promotor(en): J.E. Ligthart. - S.l. : s.n. - ISBN 9789461734693 - 186
vermeerderingsmateriaal - plantenveredeling - kwekersrecht - intellectuele eigendomsrechten - internationale handel - innovaties - beleid - landbouwsector - landbouwbedrijven - productie - wereld - ontwikkelingslanden - propagation materials - plant breeding - breeders' rights - intellectual property rights - international trade - innovations - policy - agricultural sector - farms - production - world - developing countries
Seed is the physical embodiment of the invention of the plant breeder. Plant varieties thus constitute a special form of innovation, and an assessment of intellectual property right (IPR) systems needs to take this into account. This thesis concentrates on IPRs but breeders do have a number of means by which they can capture part of the benefits from the cultivation of their new variety, rather than these falling into to public domain.
Analyzing efficiency of vegetable production in Benin
Singbo, A.G. - \ 2012
Wageningen University. Promotor(en): Alfons Oude Lansink, co-promotor(en): Grigorios Emvalomatis. - S.l. : s.n. - ISBN 9789461732774 - 128
groenten - productie - landbouwproductie - boerenmarkten - efficiëntie - analyse - benin - afrika ten zuiden van de sahara - vegetables - production - agricultural production - farmers' markets - efficiency - analysis - benin - africa south of sahara
The objective of this research is to investigate the production technology and efficiency of vegetable production and marketing at the farm level in Benin. Using recent advances in cross sectional efficiency analysis, we analyze two samples of vegetable producers following different perspectives. First, the empirical results show that farms’ inefficiency in lowland farming systems is the most diverse. Second, the results suggest that vegetable producers are more inefficient with respect to marketing than production and that marketing inefficiency is affected by the type of marketing arrangements. Third, the analysis shows that vegetable producers have an incentive for specialization and that the degree of specialization has a positive effect on technical efficiency. Finally, the results on pesticide use provide evidence that pesticides are overused while there is no evidence of technical interdependence between pesticides and productive inputs
Who cares about research?! : a study on the role of research in policy processes in competing claims contexts
Schut, M. - \ 2012
Wageningen University. Promotor(en): Cees Leeuwis, co-promotor(en): Annemarie van Paassen. - S.l. : s.n. - ISBN 9789461731487 - 280
natuurlijke hulpbronnen - nuttig gebruik - hulpbronnengebruik - onderzoek - invloeden - beleidsprocessen - waterbeheer - ruimtelijke ordening - polders - biesbosch - nederland - biobrandstoffen - productie - duurzaamheid (sustainability) - mozambique - natural resources - utilization - resource utilization - research - influences - policy processes - water management - physical planning - polders - biesbosch - netherlands - biofuels - production - sustainability - mozambique
A study on the role of research in policy processes in competing claims contexts
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