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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Ky’osimba Onaanya: understanding productivity of East African Highland banana
Taulya, G. - \ 2015
Wageningen University. Promotor(en): Ken Giller, co-promotor(en): Peter Leffelaar; P.J.A. van Asten. - Wageningen : Wageningen University - ISBN 9789462575615 - 167
bananen - musa - droogte - voedingsstoffenbeschikbaarheid - kalium - stikstof - kunstmeststoffen - afrika - uganda - gewasgroeimodellen - beslissingsmodellen - drogestofverdeling - groeianalyse - licht - fenotypische variatie - bananas - musa - drought - nutrient availability - potassium - nitrogen - fertilizers - africa - uganda - crop growth models - decision models - dry matter distribution - growth analysis - light - phenotypic variation

Over 30 million people in East Africa depend on East African highland bananas for food and income. The bananas are grown with limited additions of nutrients and no irrigation, despite widespread poor soil fertility and regular dry seasons. This thesis describes the effect of increasing rainfall and application of potassium and nitrogen fertilizers on banana growth and yields. In areas that receive less than 1100 mm of rainfall per year, additional rainfall increases yields by 65%. Application of potassium increases yields by 88%, while nitrogen is not required. A framework for computing banana growth and yield in response to the amount of water stored in the soil is described. Where the soil water storage capacity is low, mulching increases yields by 10% but it has no effect in areas where the soil water storage is high. This framework is envisaged to guide improvements in banana management and productivity in East Africa.

Institutional change and economic development : evidence from natural and artefactual field experiments in Ethiopia
Melesse, M.B. - \ 2015
Wageningen University. Promotor(en): Erwin Bulte. - Wageningen : Wageningen University - ISBN 9789462574137 - 193
ontwikkelingseconomie - plattelandsontwikkeling - landbouwontwikkeling - experimenteel veldonderzoek - landbouwproductie - man-vrouwrelaties - landgebruik - land - ethiopië - oost-afrika - afrika - instellingen - development economics - rural development - agricultural development - field experimentation - agricultural production - gender relations - land use - land - ethiopia - east africa - africa - institutions

Thesis title: Institutional Change and Economic Development: Evidence from Natural and Artefactual Field Experiments in Ethiopia

Mequanint Biset Melesse

Abstract

Institutions are the essential underpinning of economic development. A large volume of empirical literature has documented conclusive evidence supporting this hypothesis. Yet, our knowledge on how to bring about institutional change and improvement is still quite imperfect. Moreover, putting in place good institutions that have undergirded the growth of the developed world has not always produced desired results in developing countries. This thesis studies the complex relationship between institutional change and economic development. Its primary focus is on the endogenous formation of institutions and outcomes of institutional changes on the quality and sustainability of other institutions and the dynamics of economic development. It employs randomized field experiments, propensity score matching and instrumental variables approaches to tackle the problem of causal inference. The results indicate that an effective institutional development requires a good knowledge of the interaction between formal and informal institutions and the complex dynamics that such interaction entails. Customary institutions are malleable. Local institutions condition the success and effects of formal institutional changes in important ways. Institutional change is a nonlinear, complex and non-ergodic process, where multiple intended and unintended outcomes are possible. Overall, the results indicate that formal and informal institutions interact out of entrenched corners with both constructive and deleterious repercussions for economic development.

Perspectives for sustainable Prunus africana production and trade. Factsheets
Ingram, V.J. ; Loo, J. van; Dawson, I. ; Vinceti, B. ; Duminil, J. ; Muchugi, A. ; Awono, A. ; Asaah, E. - \ 2015
Wageningen : LEI Wageningen UR (LEI Factsheet 2015-102) - 10
prunus africana - tropische bossen - afrika - duurzaamheid (sustainability) - medicinale planten - internationale handel - overheidsbeleid - tropical forests - africa - sustainability - medicinal plants - international trade - government policy
This brief documents current knowledge about pygeum (Prunus africana). It aims to inform decision makers in governments in producing and consumer countries, international and civil society organisations and researchers, about sustainable (international) trade and governance of the species.
African rice (Oryza glaberrima) cultivation in the Togo Hills: ecological and socio-cultural cues in farmer seed selection and development
Teeken, B.W.E. - \ 2015
Wageningen University. Promotor(en): Paul Richards; Paul Struik, co-promotor(en): Harro Maat; Edwin Nuijten. - Wageningen : Wageningen University - ISBN 9789462574359 - 306
oryza glaberrima - rijst - familiebedrijven, landbouw - veredelde rassen - sociale gebruiken - voedselzekerheid - afrika - oryza glaberrima - rice - family farms - improved varieties - social customs - food security - africa
The African Greenhouse : a toolbox
Elings, A. ; Hemming, S. ; Os, E.A. van; Campen, J.B. ; Bakker, J.C. - \ 2015
Bleiswijk : Wageningen UR Glastuinbouw (Rapport GTB 1360) - 52
greenhouse horticulture - greenhouses - greenhouse crops - greenhouse technology - protected cultivation - decision models - crop growth models - simulation models - africa - glastuinbouw - kassen - kasgewassen - kastechniek - teelt onder bescherming - beslissingsmodellen - gewasgroeimodellen - simulatiemodellen - afrika
There is demand for a decision support tool to design greenhouse production systems in various climate zones and locations in Africa: the ‘Toolbox Adaptive Greenhouse Systems for Africa’. Selection of a limited number of climate zones that are representative for Africa limits the variation in designs to be evaluated and makes the approach more effective for the Netherlands supply industry. The toolbox will result in a number of greenhouse cultivation systems that are most suitable for a given location, weighing perspectives such as greenhouse type, greenhouse installation, climate, production and economic viability. The toolkit will follow the ‘adaptive greenhouse approach’ in which models for greenhouse, crop and finances are combined. This report provides a basis for the toolbox. An overview of African climates is given, followed by options for greenhouse design which are placed in the context of a number of production systems. The expected future developments and the transitions from current situations to likely future situations are briefly described. Anticipating likely future developments enables an analysis of the potential of a certain farm type, the requirements for further development, and the options for Netherlands involvement.
Unlocking resources in savannas: how goats and other mixed feeders overcome the negative effects of tannins
Mkhize, N.R. - \ 2015
Wageningen University. Promotor(en): Herbert Prins, co-promotor(en): Fred de Boer; Ignas Heitkonig. - Wageningen : Wageningen University - ISBN 9789462574274 - 110
geiten - tanninen - diervoeding - diervoedering - savannen - afgrazen - graasduur - begrazing - dierfysiologie - plantensamenstelling - afrika - goats - tannins - animal nutrition - animal feeding - savannas - browsing - grazing time - grazing - animal physiology - plant composition - africa

Abstract

This thesis contributes insights on how condensed tannins might mediate the interactions between woody plants and large herbivores in the African savannas. Current understanding in this regard is still based on data from short-term laboratory experiments, mostly with confined animals and a few correlative field studies that only explore relationships between tannin concentrations of plants with their intake. Although these experiments are a necessary first step in isolating and characterising the effects of condensed tannins, they oversimplify the complex interactions that occur between wild herbivores or livestock and plants. The challenge for research is to translate the roles of tannins in plant-herbivore interactions from controlled experiments to field conditions. The aims of this research were: to (1) investigate how condensed tannins influence foraging behaviour and growth performance of free-ranging ruminant herbivores, and (2) determine the effects of supplements on use of woody plants and intake rates of condensed tannins by free-ranging herbivores in a semi-arid savanna.

Field experiments were conducted and data collected on free-ranging goats as models for all mixed feeders that share similar characteristics with goats. Condensed tannin exposure levels to goats were experimentally increased in the field by orally dosing 15 goats with 20g condensed tannin powder extracted from a bark of tannin-rich species. To reduce tannin exposure, 15 goats were dosed with 20 g of PEG in an attempt to neutralize tannin effects, and another group of 15 goats was dosed only with water and served as a control group. Feeding behaviour of goats supplemented with a protein-rich source, an energy-rich source were compared with that of goats that were not supplemented.

The results indicated that mixed feeders exposed to high levels of condensed tannins spend more time grazing and less time browsing compared to animals with low tannin exposure. However, the findings did not support expectation for tannins to reduce overall foraging time. Therefore, it was concluded that condensed tannins do not necessarily suppress foraging, but only influence the amount of time animals spend foraging on either herbaceous or woody forage. These findings also supported hypothesis that herbivores forage in ways that minimize their intake rate of condensed tannins. Animals altered their foraging behaviour depending on the treatment groups they were allocated to, and compiled diets that indicated tannin minimization as a goal. Moreover, there was support for the notion that condensed tannins are digestibility reducers. It was clear that free-ranging animals are able to employ their behavioural adaptations to chemical defences in ways that mitigate the negative physiological effects on their presumed ultimate fitness. This thesis presents possible effects of nutrient-tannin/toxin interactions on herbivores in African savannas. In the supplementation experiment, proteins and energy equally increased browse consumption by herbivores, with a concomitant increase in tannin intake rates.

These results were explained in light of the ongoing bush encroachment in the African savannas. The expected increase in the availability of browse will probably impose a selection pressure for herbivores that can better utilise the encroaching woody plants known to be endowed with tannins and other carbon-based secondary metabolites. These results are used to generalise about the herbivore health, herbivore nutritional, and environmental benefits that are possible from managing our rangelands and herbivores in ways that increase utilization of chemically defended plants. For example, increased consumption of tannin-rich forage will not only improve nutrition, but it will also reduce internal parasite burden, and reduce bloating by ruminant herbivores while simultaneously reducing the methane emissions that lead to global warming.

Africa Agribusiness Academy (AAA) Year Report 2014
Nijhoff, G.H. ; Vugt, S.M. van - \ 2015
Centre for Development Innovation, Wageningen UR - 48
agribusiness - agricultural development - agriculture - policy - agricultural policy - farms - farming - east africa - africa - landbouwindustrie - landbouwontwikkeling - landbouw - beleid - landbouwbeleid - landbouwbedrijven - landbouw bedrijven - oost-afrika - afrika
The Africa Agribusiness Academy (AAA) supports African SME agrifood companies in growing their business. An AAA member companies can enhance knowledge, skills and expertise, and get support in accessing finance and markets. By the end of 2014, AAA had 200 members in five countries: Tanzania, Kenya, Uganda, Ethiopia and Rwanda. These members are in the business of sourcing from or supplying to farmers. AAA’s goal is that by stimulating business growth of the SMEs it indirectly supports business growth of the farmers that are linked to these companies.
Investigating the suitability of constructed wetlands for the treatment of water for fish farms
Heijden, P.G.M. van der; Dien, F. van; El-Beshbishi, D.A. - \ 2015
Wageningen : Centre for Development Innovation, Wageningen UR (Report / CDI 15-079) - 27
wetlands - artificial wetlands - fish farms - heavy metals - farming - pesticides - waste water - tilapia - development projects - egypt - north africa - africa - helofytenfilters - viskwekerijen - zware metalen - landbouw bedrijven - pesticiden - afvalwater - ontwikkelingsprojecten - egypte - noord-afrika - afrika
Many fish farms in Egypt rely on water of drainage canals to fill the fish ponds. There is a risk that this water is contaminated with pesticides and heavy metals. This report describes the results of a collaborative project that took place in 2012-2014 and that aimed to test the suitability of a constructed (engineered) wetland as treatment device for the removal of such pollutants from drainage canal water on a private fish farm in Egypt
Do not fear the supernatural! : the relevance of ritual plant use for traditional culture, nature conservation, and human health in western Africa
Quiroz, D. - \ 2015
Wageningen University. Promotor(en): Marc Sosef, co-promotor(en): T.R. van Andel. - Wageningen : Wageningen University - ISBN 9789462572607 - 250
traditionele geneeskunde - medicinale planten - etnobotanie - religie - geneeskrachtige kruiden - rituelen - afrika - traditional medicine - medicinal plants - ethnobotany - religion - herbal drugs - rituals - africa

Summary

Plants still play an overriding role in African traditional medicine, as large sectors of the continent’s population prefer or considerably rely on herbal treatments as their primary source of health care. Traditional medicine, which is defined as the sum of knowledge, skills, and practices used to prevent and treat diseases, often involves consultation with spiritual healers and diviners, who in turn consult supernatural entities to diagnose their patients. At the same time, these traditions and the rites that are related to their practice are categorised as “obscure” and considered unscientific by academia.

The overall aim of this thesis was to advance the understanding of the different dimensions of plant use in the context of traditional religions in two western African countries: Benin and Gabon. First, by documenting the use of plants by adepts of Vodoun in Benin and Bwiti in Gabon; and second, by exploring the associated knowledge that sustains these practices. Its purpose was to contribute to an improved plant resource management and, ultimately, the development of culturally appropriate interventions aimed at the conservation of useful plant species and their ecosystems, as well as the improvement of human health in settings similar to those of our countries of study.

Departing from the disciplinary perspective of ethnobotany, this work included theories and quantitative and qualitative methods of data collection and analysis drawn from botany, anthropology, ethnology, ecology, and pharmacology. Data were collected in a period of more than a year, which was divided in two fieldwork stays, each in Benin and Gabon.

This thesis was organised into six chapters. In Chapter One, I laid out the conceptual framework and introduced the study sites. Based on an assessment of the relevance of this study, I framed its overall objective and research questions.

Medicinal plants are not only acknowledged for their importance in satisfying the health needs of people in sub-Saharan Africa, but also for the role their commercialization plays as a source of income for vulnerable groups. In spite of this recognition, little is known about the implications of medicinal plant trade for the sustainability of the plant species involved, especially when data on the volume and diversity of species sold at the markets are not available. In Chapter Two, we addressed this gap by providing an estimation of the volume and economic value of the domestic market in herbal medicine in Benin. We also highlighted local health concerns reflected by the medicinal plant market and found that ritual plants were the largest use category for which vendors catered in the markets of Benin. Additionally, we suggested some species with possible sustainability issues.

In Chapter Three, we explored the potential link between two different social mechanisms that regulate the use of plant resources (taboos and sacrifices) and the scarcity of ritual plants in Benin and Gabon. The scholarly discussion around the origin and necessity of taboos has found these to exist either as a means to avoid potential diseases or to control the use of natural resources. Moreover, empirical data has shown that taboos reflect resource abundance. These studies, however, have primarily focussed on the use of wild animals as food. By providing quantitative data based on questionnaires with local informants, we found evidence that restrictions (such as taboos and sacrifices) were an indication of resource scarcity of ritual plants, thus advancing new explanations to the existence of these social mechanisms.

In Chapter Four, we revised two of the notions that are central to our study: ‘religion’ and ‘traditional religion’, this time as defined by the people who profess these faiths in Benin and Gabon. Plant use in the context of traditional religions has been commonly described from an outsider’s perspective. The same is true for religion and traditional religions. In this chapter, we learnt that plants played a central role in the religious traditions of Benin and Gabon, both for adepts and non-adepts of Vodoun and Bwiti.

In Western science, the effects of ritual plants on human health have been proposed to be a matter of belief. In Chapter Five, we discussed the potential pharmacological effect of culturally salient and economically important ritual plants on their users. We did that by contrasting their mode of application to proven pharmacological properties gathered from the literature. Additionally, we described folk categories of illness related to supernatural agents (e.g. evil spirits, ancestors, and sorcerers), as well as diseases recognised by biomedicine but that are attributed supernatural causes by people in Benin and Gabon. We discovered that in both countries an important proportion of the ritual applications of plants suggest a pharmacological effect on their users.

Finally, in Chapter Six, I addressed the research questions formulated in Chapter One and discussed our work’s methodological issues as well as its implications to other scientific disciplines. I also highlighted the possible applications of the research results in informing nature conservation and human development interventions, as well as some possibilities for future research. Moreover, I reached five conclusions about Bwiti and Vodoun in our countries of study: (1) Plants and other elements of the natural world play a central role in the religious traditions of Benin and Gabon, both for adepts and non-adepts of these traditions. (2) Social mechanisms such as taboos and sacrifices are a form of adaptive management of plant resources that respond to perceived scarcity of ritual plants by their users. (3) Ritual applications of plants used in our countries of study suggest a pharmacological effect on their users, as opposed to the previous assumption that their effectiveness is a matter of belief. (4) By being the backbone of the medinal plant trade in Benin and Gabon, ritual plants represent an important source of income for a substancial sector of the population of these two countries. (5) The Western notion of ‘ritual’ in the context of western African plant use is an important mechanism for the preservation and transmission of ecological, historical, and medicinal knowledge. These conclusions point to the need to question the assumptions upon which the study of plant use in the western African context has been typically approached. Finally, I concluded that as long as the exercise of agency by supernatural entities is acknowledged, considering these practices as ‘religious’ is justified from an etic perspective.

Supporting Local Seed Businesses : A Training Manual for ISSD Uganda
Mastenbroek, A. ; Chebet, A. ; Muwanika, C.T. ; Adong, C.J. ; Okot, F. ; Otim, G. ; Birungi, J. ; Kansiime, M. ; Oyee, P. ; Ninsiima, P. - \ 2015
Wageningen : Centre for Development Innovation, Wageningen UR - 273
seed production - seed development - seed quality - rural development - farming - markets - businesses - small businesses - regional development - training courses - training - agricultural development - uganda - west africa - africa - zaadproductie - zaadontwikkeling - zaadkwaliteit - plattelandsontwikkeling - landbouw bedrijven - markten - bedrijven - kleine bedrijven - regionale ontwikkeling - scholingscursussen - opleiding - landbouwontwikkeling - west-afrika - afrika
The training manual is developed in Uganda to train partner organisations in coaching farmer groups to become sustainable local seed businesses. It introduces the Integrated Seed Sector Development Programme in Uganda and the concept of local seed businesses (LSBs). The manual has 5 modules covering selection, monitoring and sustaining local seed businesses; technically equipping local seed businesses, professionally organising LSBs; orienting LSBs to the market and strategically linking them to service providers.
Unravelling the genetics of iron status in African populations : candidate gene association studies
Gichohi-Wainaina, W.N. - \ 2015
Wageningen University. Promotor(en): Michael Zimmermann; Edith Feskens, co-promotor(en): Alida Melse-Boonstra; G.W. Towers. - Wageningen : Wageningen University - ISBN 9789462572102 - 198
ijzergebrekanemie - voeding - genetische factoren - eiwitten - volksgezondheid - voeding en gezondheid - populaties - afrika - iron deficiency anaemia - nutrition - genetic factors - proteins - public health - nutrition and health - populations - africa

Abstract

Background: Investigating the manner in which genetic and environmental factors interact to increase susceptibility to iron deficiency, has the potential to impact on strategies to overcome iron deficiency as well as the development of biomarkers to monitor iron status in populations. Single nucleotide polymorphisms or genetic variants that may affect the composition and hence the functionality of proteins involved in iron metabolism have been the subject of recent genetic association studies. However, these investigations have not yet been carried out in African populations that differ genetically from populations of European ancestry and which bear the highest burden of iron deficiency. The overall aim of this thesis was to investigate the genetics of iron status in African populations using a candidate gene approach.

Methods: In order to evaluate the association between identified TMPRSS6 gene variants and iron status we conducted a systematic review with meta-analyses. We primarily searched the literature using the HuGE Navigator, Pubmed and Scopus databases for primarily genome wide association studies. Fixed effects meta-analysis was used to obtain summary estimates. Associations between reported variants and iron status as well as gene-gene and variant interactions that influence iron status were investigated in a female black South African cohort (n=686; range 32–86 years) which were part of the Prospective Urban and Rural Epidemiology (PURE) study. Concentrations of haemoglobin, serum ferritin, serum transferrin receptor and body iron stores were determined. Thirty SNPs were genotyped and passed all quality criteria. To investigate whether previously identified associations in populations of European ancestry are replicated in populations of African ancestry, we conducted candidate gene association studies. Twenty iron status-associated variants in 628 Kenyans, 609 Tanzanians, 608 South Africans and 228 African Americans were genotyped and associations investigated using haemoglobin and serum ferritin as outcome measures. Finally, we assessed the effect of TNF-α allele variants (TNF‒1031, TNF‒308) on malaria rates, the severity of malaria as indicated by haemoglobin concentrations at the time of presentation with febrile episodes and the association between Plasmodium infection and haemoglobin concentration in symptomless parasite carriers. We used data from a placebo-controlled trial which consisted of 612 Tanzanian children aged 6–60 months. Cox regression models were used in the primary analysis to account for multiple episodes per child.

Results: In our systematic review we included eleven studies on Caucasian populations, four on Asian populations and one study on an African-American population. Differences in minor allele frequencies (MAF) of 8 TMPRSS6 SNPs (rs855791, rs4820268, rs2111833, rs1421312, rs228921, rs228918, rs228919 and rs575620) across ethnic groups were observed; with the MAF of rs855791 being significantly higher in Asian populations than in Caucasians (0.55 vs 0.42). In the meta-analysis, the A allele of rs855791 was associated with lower haemoglobin and ferritin concentrations in all populations. This allele was also associated with increased serum transferrin receptor and transferrin concentrations. We observed similar associations for the G allele in rs4820268. In general, minor allele frequencies (MAF) from females in the PURE population were lower compared to those of males and females of European ancestry populations in the 1000 Genomes Project. In the TF gene, the SNP rs1799852 was associated with decreased serum ferritin (p=0.01) and body iron concentrations (p=0.03) and increased serum transferrin receptor (sTfR) concentrations (P=0.004), while rs3811647 was associated with transferrin receptor and body iron (both P=0.03) in a U-shaped manner. The chromosome 6 SNP allele combination (AAA) consisting of rs1799964 and rs1800629 both in TNF α and rs2071592 in NFKBIL1 was associated with higher odds for low serum ferritin concentrations (serum ferritin<15µg/L; OR:1.86 (95%-CI, 1.23-2.79)). The chromosome 22 SNP allele combination (GG) consisting of rs228918 and rs228921 in the TMPRSS6 gene was associated with lower odds for increased sTfR concentrations (sTfR>8.3mg/L; OR:0.79 (95%-CI,0.63-0.98). We successfully replicated reported significant associations with lowered haemoglobin concentrations for two loci in TMPRSS6 namely rs2413450 and rs4820268 and with increased haemoglobin concentrations for one locus in TF (rs3811658) when analysing the four populations of African ancestry. When ferritin was considered as an outcome measure, we replicated associations with increased ferritin concentrations in two loci namely, rs228918 in TMPRSS6 and rs1525892 in TF. No other significant associations were determined. Malaria rates were higher in Tanzanian children with the TNF‒1031CC genotype (rs1799964) compared to the AA genotype (crude hazard ratio (HR), 95%CI: 1.41 [1.01‒1.97], adjusted HR 1.31 [0.97‒1.76]y) but were lower in those with the TNF‒308AA genotype (rs1800629) (adjusted HR 0.13 [0.02‒0.63]) compared to those harbouring the wild type homozygous genotype.

Conclusions: This thesis demonstrates previously observed associations between TMPRSS6 gene variants and haemoglobin concentrations in European ancestry populations are replicated in African populations. Replication of results in other loci previously associated with iron status in European ancestry populations was not achieved. Additionally, minor allele frequencies of single nucleotide polymorphisms associated with iron status are generally higher in European ancestry cohorts compared to those of African ancestry populations. The lack of association of reported variants may indicate that novel loci are responsible for the heritability of iron status in African populations. We have additionally observed that TNF α variants increase malaria severity. Malaria is a major cause of iron deficiency in malaria endemic areas. Our finding emphasizes that to alleviate iron deficiency in malaria endemic areas prevention and treatment of malaria is necessary. This thesis highlights the need to conduct genetic association studies in African populations where iron deficiency is of utmost public health significance. In addition, investigations into the genetics of iron status are bound to contribute towards the development of biomarkers that are useful in the determination of iron status in areas of high inflammation burden.

The roles of exploration and exploitation in the export market integration of Beninese producers at the base of the pyramid
Adékambi, S.A. - \ 2015
Wageningen University. Promotor(en): Hans van Trijp, co-promotor(en): Paul Ingenbleek. - Wageningen : Wageningen University - ISBN 9789462572461 - 205
marketing - landbouwproducten - export - instellingen - armoede - sheaboter - ontwikkelingseconomie - economische groei - afrika - benin - west-afrika - marketing - agricultural products - exports - institutions - poverty - shea butter - development economics - economic growth - africa - benin - west africa

Keywords: Base of the pyramid, Bottom of the pyramid, Supply chains, Export market integration, Market learning, Developing and Emerging countries, Exploitation and Exploration, Institutional arrangements, Transaction cost economics, Livelihood performance, BoP producers

Abstract

Organizing supply chains that are based in producer groups that live in conditions of widespread poverty and weak institutional support (sometimes referred to as the Base of the Pyramid [BoP] producers) is challenging. These challenges have predominantly been studied in the development literature, while the marketing perspective has received less attention. Drawing on both transaction cost and market learning theories, the thesis integrates producers’ opportunity exploitation and exploration processes with the institutional framework adopted in the development literature to understand producers’ integration with export markets. Overall, the findings show that exploitation mediates between drivers investigated by development economists (quality of infrastructure, microcredit, and community culture) and integration with export markets. The results show that BoP producers’ export market integration also depends on the institutional arrangements that exporting companies offer. The results indicate that contrary to more-developed settings like those in Western Europe and Northern America, there is no need to develop both opportunity exploration and exploitation in environments characterized by scarce opportunities with relatively high purchasing powers. The findings imply that developing competencies that enable to produce the demanded quality are crucial in seizing export market integration opportunities.

Launching the Delta Alliance: business development report phase 3
Driel, W.F. van; Peters, R. ; Guchte, C. van de - \ 2014
Wageningen : Delta Alliance - 23
klimaatverandering - overstromingen - kustgebieden - delta's - azië - afrika - amerika - europa - climatic change - floods - coastal areas - deltas - asia - africa - america - europe
Delta Alliance is an international knowledge-driven network organisation. Its mission is to improve the resilience of deltas through more integrated and effective efforts, building on scientific research and knowledge exchange. It aims at disclosure of knowledge for application by a wide audience of end-users from the knowledge institutions, public partners and private sector, as well as to identification of upcoming research agendas
Global asessment of manure management policies and practices
Teenstra, E.D. ; Vellinga, Th.V. ; Aktasaeng, N. ; Amatayaku, W. ; Ndambi, A. ; Pelster, D. ; Germer, L. ; Jenet, A. ; Opio, C. ; Andeweg, K. - \ 2014
Wageningen : Wageningen UR Livestock Research (Livestock research report 844) - 33
mestbeleid - dierlijke meststoffen - veehouderij - best management practices - geïntegreerde bedrijfssystemen - azië - afrika - latijns-amerika - manure policy - animal manures - livestock farming - integrated farming systems - asia - africa - latin america
The Livestock and Manure Management Component (LMMC) of the CCAC Agriculture Initiative supports integrated manure management practices by increasing knowledge and awareness, removing barriers to action and enhancing practice change. This Global Assessment report provides an overview of manure policies and an in-depth assessment of on-farm manure management practices in three regions: Asia, Africa and Latin America.
Comparative assessment of the vulnerability and resilience of deltas : extended version with 14 deltas : synthesis report
Bucx, T. ; Driel, W.F. van; Boer, H. de; Graas, S. ; Langenberg, V. ; Marchand, M. ; Guchte, C. van de - \ 2014
Delft-Wageningen : Delta Alliance - ISBN 9789492100030 - 60
hoogwaterbeheersing - kustgebieden - delta's - landgebruik - klimaatverandering - afrika - azië - europa - amerika - flood control - coastal areas - deltas - land use - climatic change - africa - asia - europe - america
Worldwide, deltas host dense populations and are important centres of agricultural and industrial production, and economic activity. Many deltas are areas of great ecological importance as well, featuring wetlands of high and unique biodiversity. Deltas are vulnerable to changes by natural forces and human activities. Major drivers of change are population growth, economic development, climate change and subsidence.
Launching the Delta Alliance: Content report phase 3
Bosch, R. van den; Bucx, T. ; Klostermann, J.E.M. ; Wijsman, P. ; Driel, W.F. van; Guchte, C. van de - \ 2014
Wageningen : Delta Alliance - 23
klimaatverandering - overstromingen - kustgebieden - delta's - azië - afrika - amerika - europa - climatic change - floods - coastal areas - deltas - asia - africa - america - europe
Delta Alliance is an international knowledge-driven network organisation. Its mission is to improve the resilience of deltas through more integrated and effective efforts, building on scientific research and knowledge exchange. It aims at disclosure of knowledge for application by a wide audience of end-users from the knowledge institutions, public partners and private sector, as well as to identification of upcoming research agendas
Beter zaad voor Afrika
Boo, M. de; Thijssen, M.H. - \ 2014
WageningenWorld (2014)4. - ISSN 2210-7908 - p. 28 - 31.
kwaliteit - zaden - plantenvermeerdering - rassen (planten) - zaadproductie - zaadkwaliteit - overheid - afrika - tuinbouw - plantenveredeling - pootknollen - geografische rassen - quality - seeds - propagation - varieties - seed production - seed quality - public authorities - africa - horticulture - plant breeding - seed tubers - geographical races
Veel Afrikaanse boeren blijven verstoken van goed zaai- en pootgoed. Nationale overheden en bedrijven kunnen niet aan de vraag voldoen. Het Centre for Development Innovation in Wageningen werkt met boerengroepen om lokaal beter zaaizaad op de markt te brengen.
Vis langer houdbaar dankzij vriesdroger op zonne-energie
Bartels, P.V. - \ 2014
Wageningen UR
visproducten - vis - voedselbewaring - voedselverspilling - vriesdroging - droogmethoden - visverwerking - gedroogde vis - afrika - fish products - fish - food preservation - food wastage - freeze drying - drying methods - fish processing - dried fish - africa
In veel Afrikaanse landen gaat vis verloren omdat er geen koeling voorhanden is. Een vriesdroger die is ontwikkeld door de Wageningse onderzoeker Paul Bartels en Ebbens Engineering is veel verspilling te voorkomen. De gedroogde vis is ook zonder koeling lang houdbaar.
The impact of UTZ certification of cocoa in the Ivory Coast 2008 to 2013
Ingram, V.J. ; Waarts, Y.R. ; Vugt, S.M. van; Ge, L. ; Wegener, L. ; Puister-Jansen, L.F. - \ 2014
Wageningen : LEI Wageningen UR - 16
ivoorkust - afrika - certificering - cacao - theobroma cacao - cacaoproducten - duurzaamheid (sustainability) - cote d'ivoire - africa - certification - cocoa - cocoa products - sustainability
In 2008, various value chain partners in Ivory Coast adopted the UTZ Code of Conduct and became UTZ certified to enhance sustainability in the cocoa supply chain. As part of the certification programme, cooperatives and are receiving training on farm management organisational capacity building. This brochure paints a picture of the situation on farms by mid-2013. It provides information about how the UTZ Certified cocoa programme in Ivory Coast is helping farmers to increase their knowledge and use good agricultural practices (GAPs) in line with the UTZ Certified Code of Conduct. The lessons learned from these results will be used to improve the quality of the programme.
Effect of species richness on disease risk: dilution effect and underlying mechanisms
Huang, Z. - \ 2014
Wageningen University. Promotor(en): Herbert Prins, co-promotor(en): Fred de Boer; Frank van Langevelde. - Wageningen : Wageningen University - ISBN 9789462570894 - 73
dierziekten - bovidae - rundvee - risico - soortenrijkdom - ziektedistributie - pathogenen - ziekteoverdracht - modellen - afrika - animal diseases - bovidae - cattle - risk - species richness - disease distribution - pathogens - disease transmission - models - africa

Summary

any pathogens infect multiple host species which can differ in their reservoir competence. Consequently the species richness and composition of the host community can considerably influence the dynamics of disease transmission.

Recently, an increasing number of studies reported the existence of a dilution effect whereby high host species richness reduces the disease risk. However, the generality of the dilution effect and its mechanisms are still highly debated.

In this thesis, I tested the existence of a dilution effect in bovine tuberculosis (BTB) and investigated the underlying mechanisms of the dilution effect.

I detected a possible dilution effect in BTB, where higher mammal species richness reduced the probability of occurrence of BTB at a regional level in Africa, after correcting for cattle density (Chapter 2).

This dilution effect might be caused by encounter reduction, i.e. the presence of non-competent mammal species might act as barriers to herd movement of cattle and reduce encounter rates among herds, which leads to a decreased probability of BTB outbreaks.

Then I extended the study of the BTB dilution effect to the analysis of BTB persistence and recurrence (Chapter 3).

The results showed that mammal species richness was also negatively correlated with the BTB persistence and recurrence.

Besides, I demonstrated that the presence of African buffalo, as a maintenance host for

Mycobacterium bovis (the causative agent of BTB), had a positive identity effect and increased the risk of BTB persistence and recurrence, whereas greater kudu distribution was not correlated with BTB persistence or recurrence.

In addition, BTB persistence and recurrence were correlated with different sets of risk factors.

In Chapter 4, I showed that interspecific variation in species’ reservoir competence could be partly explained by life-history traits in three vector borne diseases, namely Lyme disease, West Nile Encephalitis (WNE) and Eastern Equine Encephalitis (EEE). Species with larger body mass (for hosts of Lyme disease and WNE) or smaller clutch size (for hosts of EEE) had a lower reservoir competence. Given that both larger body mass and smaller clutch size are linked to higher extinction risk of local populations, the results indicate that species with a higher reservoir competence are more likely to remain in the community when biodiversity declines, and thereby potentially increase the risk of transmitting these pathogens.

This might be a possible mechanism underlying the dilution effect.

Combing the results about the relationships between species’ reservoir competence and life-history traits, I constructed a compartmental model to investigate the effect of connectivity on the risk of directly transmitted diseases in metapopulations (Chapter 5).

I showed that different indicators of disease risk (infection prevalence and number of infected individuals) reacted differently to increasing connectivity.

Higher connectivity can not only decrease disease risk due to the dilution effect by increasing species richness, but can also increase disease risk through increasing contact rates among patches (facilitation effect).

The net impact of connectivity depends on the relative importance of the dilution versus facilitation effect.

These results may reconcile the current debate on the dilution effect, and contributes to a better understanding of the impacts of fragmentation on disease risks and the generality of the dilution effect.

M Finally, I combined these findings and reviewed the evidence and critiques on the dilution effect (Chapter 6).

Latest studies (also the BTB study in this thesis) tried to test species identity effects, caused by particular species in communities, and found that the identity effect and dilution effect can operate simultaneously in the host community.

I suggest that the identity effect could act as an additional mechanism explaining the effect of species richness on disease risk.

A weak correlation between host reservoir competence and local extinction risk can create inconsistent effects of host species richness on disease risk.

Moreover, different indicators of disease risk may react differently to the changes in species richness.

This could also be one of the reasons for the controversial results from previous studies that used different indicators (e.g., prevalence or number of infection) of disease risk.

In conclusion, this thesis presents both evidence and critique for the existence of the dilution effect.

Since factors may simultaneously influence community compostion and the characteristics of pathogen transmission (e.g., susceptibility, survival of pathogen etc.), future studies should also consider these factors, rather than only species richness, to better understand the effect of species richness on disease risk.

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