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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Ecology and biology of Rhamphicarpa fistulosa, a new parasitic weed of Rain-fed Rice (Oryza sativa) in sub-Saharan Africa
Kabiri, Stella - \ 2017
Wageningen University. Promotor(en): Niels Anten, co-promotor(en): Lammert Bastiaans; J. Rodenburg. - Wageningen : Wageningen University - ISBN 9789463436052 - 130
oryza sativa - parasitic weeds - crop ecology - orobanchaceae - weed control - africa south of sahara - parasitaire onkruiden - gewasecologie - onkruidbestrijding - afrika ten zuiden van de sahara

Rice is an important staple food crop in Africa. The increasing scarcity of agricultural land has driven rice growers to expand into marginal areas that have natural infestations of Rhamphicarpa fitulosa. In return, R. fistulosa has increasingly become a serious problem to rice production in sub-Saharan Africa. To date, the understanding of the ecology and biology of the species and its dependence and effects on a host, is rather limited. The discrepancy between the emergence of this weed problem and the virtual absence of knowledge on the weed species motivated the study presented in this thesis.

In a field survey in Tanzania, Striga asiatica was observed in higher lying and drier fields, while R. fistulosa was observed in the lower lying wetter fields. Experiments confirmed that S. asiatica is favoured by free-draining soils and R. fistulosa by water-logged soils. These results imply that changes in climate, specifically moisture regimes, will be crucial for the future prevalence of both parasitic weed species. In a second investigation, I found that daylight and completely saturated soil conditions were prerequisites for germination, demonstrating that R. fistulosa is a typical species of environments with fluctuating water levels. Neither root exudates collected from rice host plants, nor the synthetic germination stimulant GR24, triggered germination of R. fistulosa seeds. Host plant presence resulted in a 3.7 times higher seed production rate and a 15% larger average seed size. The absence of a host recognition mechanism at the germination stage suggests that either the regulation of germination through light and soil moisture is near optimal, or that for this parasitic plant species an opportunistic germination strategy is superior. In a third study, I observed that infection by R. fistulosa led to significant reductions in leaf photosynthetic rate, stomatal conductance, the quantum efficiency of PSII (ΦPSII) and chlorophyll content of rice. In addition, there was a 19-32% negative deviation of the linear relationship between quantum yield of CO2 assimilation (ΦCO2) and quantum efficiency of PSII (ΦPSII) of infected plants in comparison to un-infected plants. This indicated a parasite induced influence on the photochemical process of the host. Furthermore, there was a considerable time lag between the parasite’s gains in growth and the reduction of host photosynthesis. The reduction in host growth, coincided with suppression of host photosynthesis. This indicates that R. fistulosa affects host growth by first extracting assimilates and making considerable gains in growth, before it affects the host photosynthesis. In the final investigation, I examined how the interaction between host plant and parasite influenced growth and (re)production of R. fistulosa and rice. Infection by R. fistulosa increased root:shoot ratio and decreased plant height, leaf area and tiller number of rice. Reductions in light interception of the host were followed by reductions in light use efficiency, causing 22-71% losses in host plant biomass and 78-100% losses in host kernel production. Parasitism eventually caused a complete standstill of host plant growth, while the parasite managed to gradually increase its share of the total host plant-parasite biomass up to 50-82%. This implies that ultimately the host plant was producing solely for the sake of the parasite.

In a final chapter, I discuss the implications of my findings for the future expansion of this parasitic weed, specifically in light of climate change. I also discuss how the divergent ecology and biology of R. fistulosa is likely to influence the effectiveness of measures that are currently applied to manage Striga spp. I argue that more than the current attention needs to be paid to R. fistulosa, specifically for the problems it causes to the rice sector in sub-Saharan Africa.

Shocks, preferences, and institutions: experimental evidence from Sub-Saharan Africa
Cecchi, F. - \ 2015
Wageningen University. Promotor(en): Erwin Bulte. - Wageningen : Wageningen University - ISBN 9789462572621 - 198
ontwikkelingseconomie - afrika ten zuiden van de sahara - institutionele economie - experimenten - veldwerk - keuzegedrag - verandering - shock - conflict - economische analyse - development economics - africa south of sahara - institutional economics - experiments - field work - choice behaviour - change - economic analysis

Both preferences and institutions are central to economic theory. Insofar as they cannot be taken as given, it is important to understand how they are formed, and how they “respond” to shocks. This thesis investigates the endogenous formation of preferences and institutions. It presents field-experimental evidence from Sub-Saharan Africa – specifically Uganda, Sierra Leone, and Ethiopia – gradually zooming out through different levels of responses to shocks. It starts by looking at the formation of individual preferences in utero and during childhood. Next, it explores the endogeneity of rational choice among adults. Finally, it looks at the cumulative outcome of these responses in terms of changes in local norms and informal institutions. Shocks are thought of in their broadest possible definition. Conflict is a shock, but so is the introduction of exogenously planned and implemented institutions, or the penetration of statutory law into predominantly customary settings.

Chapter 2 investigates the fetal origins of preferences for cooperation. I study the effect of prenatal trauma on the cooperation of those born during the Lord’s Resistance Army insurgency in northern Uganda. I find that a rise in the relative length of the index finger with respect to the ring finger – a marker for prenatal hormonal shock – reduces the child’s probability of contribution to the public good. I interpret this as evidence that prenatal trauma may affect later-life individual preferences, and that the nine months in utero may be more important than previously thought.

Chapter 3 looks at the preferences for competition towards in- and out-groups, in relation to conflict exposure. I study aggressiveness and willingness to compete among youth in Sierra Leone, using the group dynamics generated by a local football tournament to separate in- and out-group behavior. I find that football players that experienced more intense exposure to violence are more likely to get a foul card during a game. Also, I isolate competitiveness from aggressiveness in the lab, and find that conflict exposure increases the willingness to compete towards the out-group—not the in-group. I conjecture that violent conflict is not only a destructive process, but that it may also trigger autonomous transformations in believes and preferences.

Chapter 4 explores the endogeneity of rational choice among adults. I study the relationship between market exposure and rationality in rural Ethiopia, through a laboratory experiment involving sesame brokers and farmers. Following a randomly assigned trading session in a competitive auction, I find that farmers and brokers selected for the treatment behave more rationally than their peers in the control group. Markets are thus not only neutral institutions; they change the way people make decisions. I speculate that, in the presence of endogenous rationality, a rapid market expansion may offer dynamic efficiency gains, but that it may also affect the distribution of rents and wealth at the local and regional levels.

Chapter 5 investigates the relationship between formal and informal institutions. I study the dynamics of social capital – proxied by contributions to a public goods game – in response to the introduction of a formal insurance scheme in southwestern Uganda. I find that formal insurance crowds-out social capital, but that it is not those adopting the formal insurance who reduce their contributions (as predicted by theory). Instead, social capital erodes because of the uninsured. I argue that this is consistent with “weapons of the weak” theories, emphasizing social embeddedness. Those who fear to lose from this inequality-increasing innovation respond with the only “weapons” at hand—by reducing cooperation in other domains.

Chapter 6 looks at how the penetration of formal law affects customary legal institutions. I study the effects of introducing a formal legal alternative on the arbitration decisions of real customary judges in Ethiopia. I find that introducing a legal fallback reduces arbitration biases and draws the decisions of customary judges significantly closer to the formal law. At the same time, agents disfavored by the custom do not take advantage of their increased bargaining power. I argue that most effects of increased competition between formal law and customary legal institutions may rise from changes in the latter, rather than from plaintiffs seeking justice under the rule of law.

While each chapter is envisioned as a self-standing contribution to economic literature, the crosscutting thread is equally crucial. Not always do endogenous responses to shocks fit existing economic theory. Rather, the evidence presented sometimes highlights unforeseen dynamics. It moreover strongly rejects the notion of passive acceptance of shocks; individuals and institutions “respond” to shifting circumstances through “rational” – although not necessarily conscious – behavioral changes. These findings contribute to the understanding of the micro-foundations of preferences and institutions, and emphasize the need to continuously underpin theoretical predictions with empirical evidence.

How small is beautiful? : food self-sufficiency and land gap analysis of smallholders in humid and semi-arid sub Saharan Africa
Hengsdijk, H. ; Franke, A.C. ; Wijk, M.T. van; Giller, K.E. - \ 2014
Wageningen : Plant Research International, Business Unit Agrosystems Research (Report / Plant Research 562) - 46
zelfvoorziening - kleine landbouwbedrijven - voedsel - landbouwhuishoudens - huishoudens - gewasproductie - humide klimaatzones - semi-aride klimaatzones - afrika ten zuiden van de sahara - self sufficiency - small farms - food - agricultural households - households - crop production - humid zones - semiarid zones - africa south of sahara
Socio-economic impacts and determinants of parasitic weed infestation in rainfed rice systems of sub-Saharan Africa
N'cho, A.S. - \ 2014
Wageningen University. Promotor(en): Alfons Oude Lansink, co-promotor(en): Monique Mourits; J. Rodenburg. - Wageningen : Wageningen University - ISBN 9789462571266 - 160
rijst - agrarische productiesystemen - gewasproductie - onkruiden - parasitaire onkruiden - striga hermonthica - striga asiatica - controle - onkruidbestrijding - regenafhankelijke landbouw - economische impact - sociale factoren - besluitvorming - boeren - afrika ten zuiden van de sahara - benin - ivoorkust - tanzania - rice - agricultural production systems - crop production - weeds - parasitic weeds - control - weed control - rainfed agriculture - economic impact - social factors - decision making - farmers - africa south of sahara - cote d'ivoire

Keywords: rice; weed; weed management practices, adoption, impact, parasitic weeds; Rhamphicarpa fistulosa; Striga asiatica; Striga hermonthica, double hurdle model; multivariate probit, productivity, stochastic frontier analysis, data envelopment analysis, directional distance function, sub-Saharan Africa, Benin, Cote d’Ivoire, Tanzania.

Socio-economic impacts and determinants of parasitic weed infestation in

rainfed rice systems of sub-Saharan Africa

Simon A. N’cho


Rice is an important strategic crop for food security in sub-Saharan Africa. However, its production is constrained by many biotic and abiotic stress. In rainfed rice systems, weeds and particularly parasitic weeds are among the most damaging constraints. The objective of this thesis was to identify factors affecting infestation of rice farms by parasitic weeds and to assess the economic and social impact of parasitic weeds on primary producers of rainfed rice systems in order to provide guidance for decision-making for rice farmers and policymakers aiming at developing strategies for coping with parasitic weeds. To achieve this objective, we first explored biophysical characters of the rice growing environment, farmers’ management practices, and socio-economic characteristics that affect the infestation of rice fields by parasitic weeds (PWs) and farmers’ ability to cope with the problem. A double hurdle model was used to analyses simultaneously the likelihood of occurrence and the severity of infestation of the PW. The findings suggest that farmers can cope with the PW as long as they are aware of the problem provided they have a good access and management capacity of production resources. Next, we examined weed management practices (WMPs) currently available to farmers and how PW infestation affect their choices for specific combinations of WMPs using a multivariate probit model. Findings indicate that farmers are more likely to adopt improved weed management practices or combined more WMPs when their fields are infested by PWs. Species-specific and country-specific approaches and technologies are require to address the PW problem. Then, we assessed the impact of parasitic weeds infestation on farmers’ productivity and examined how this problem and managerial factors prevent farmers from achieving optimal technical efficiency levels using a stochastic frontier analysis (SFA). PWs induce productivity losses ranging from 21% to 50%. Farmers seem to cope with PW through learning from experiencing PW problem. Finally, we estimated weeding labour inefficiencies using a Data Envelopment Analysis (DEA) with directional input distance function and a single truncated bootstrap regression to identify sources of inefficiencies. Results suggest that, farmers can save substantial (58% – 69%) weeding labour without reducing rice production. No evidence was found that the currently used manual weeding modalities were able to manage parasitic weeds efficiently. The main finding of this thesis is that in sub-Saharan Africa, PWs infestation has a negative impact on rainfed rice systems’ productivity and the use of production resources. However, these impacts can be reduced if farmers have a good access to production resources and manage them efficiently.

More food from fertile grounds: Integrating approaches in order to improve soil fertility
Beek, C.L. van; Duivenbooden, N. van; Noij, G.J. ; Heesmans, H.I.M. - \ 2014
Wageningen : Alterra
bodemvruchtbaarheid - teeltsystemen - bodemdegradatie - afrika ten zuiden van de sahara - mest - soil fertility - cropping systems - soil degradation - africa south of sahara - manures
Soils represent a major natural capital asset and have enormous potential to increase agricultural production while, at the same time, combating climate change and contributing to green economic growth. Yet, every year more than €3 thousand million is lost due to soil degradation. To unlock the potential of soils, nutrients need to be used more efficiently. This can be achieved by improving the recycling of nutrients, increasing organic matter content and applying fertilizers of the right type in the right amounts, at the right time and in the right place. There are several pathways of change that have been proposed to increase the productive capacity of soils. However, with current trends – globalization, urbanization, resource scarcity and climate change – new approaches are required. In our view, such approaches should be based on Integrated Soil Fertility Management (ISFM), which includes the application of both mineral fertilizers and organic manures. Subsequently, ISFM should be supplemented with site-specific interventions and a better match between supply and demand of (locally available) nutrients to make the best use of available resources, reduce environmental impacts and enhance green economic growth. The Fertile Grounds Initiative (FGI) was designed as an coordinated strategy of collaboration between actors in nutrient management at various spatial scales. It is based on eight subcomponents, which bring together the supply and demand of nutrients within a specific geographical area to make optimum use of site-specific interventions and available nutrients, supplemented with external imports. We expect the FGI to make a significant practical contribution to sustainable development in areas with limited soil fertility and nutrient availability, while at the same time resolving problems arising from nutrient excess in certain parts of the country and from (urban) waste streams, turning these into economic assets.
Is Inclusive Business for you? Managing and upsclaing an inclusive company : Lessons from the field
Blomne Sopov, M. ; Saavedra Gonzalez, Y.R. ; Sertse, Y. ; Vellema, W. ; Verjans, H. - \ 2014
Wageningen : Centre for Development Innovation, Wageningen UR - ISBN 9789462571938 - 147
ketenmanagement - agro-industriële ketens - contractlandbouw - bedrijfssystemen - agrarische economie - economische ontwikkeling - afrika - ethiopië - burundi - kenya - mozambique - zuid-afrika - afrika ten zuiden van de sahara - markten - supply chain management - agro-industrial chains - contract farming - farming systems - agricultural economics - economic development - africa - ethiopia - south africa - africa south of sahara - markets
Can agri-food companies do it all? Develop new markets, secure supply, protect reputations, ensure profits and reduce poverty, create jobs and guarantee food supplies? Company strategies now commonly refer to ‘creating shared value’ and ‘inclusive business’. But with growing pressure on resources, a billion hungry people and some four billion people at the base of the economic pyramid by 2050, are we making progress fast enough? What options are there with real promise? And, how can all stakeholders collaborate better to bring change at scale? This report gives the outcomes of the ‘From Islands of Success to Seas of Change’ initiative on scaling inclusive agri-food markets. It combines background research, interviews and case studies with the insights of 100 leaders from business, government, NGOs, research, and farmer organizations who attended the Seas of Change workshop in April 2012. The case for scaling inclusive agrifood markets is explained and ten key challenges are explored. This leads to lessons for key stakeholders and a follow-up agenda for improved targeting of inclusive investments.
Social capital, agricultural innovation and the evaluation of agricultural development initiatives
Rijn, F.C. van - \ 2014
Wageningen University. Promotor(en): Erwin Bulte, co-promotor(en): Marrit van den Berg. - Wageningen : Wageningen University - ISBN 9789461739094 - 185
ontwikkelingseconomie - sociaal kapitaal - landbouwontwikkeling - plattelandsontwikkeling - innovaties - afrika ten zuiden van de sahara - institutionele economie - rwanda - uganda - democratische republiek kongo - landbouw - sociale netwerken - economische ontwikkeling - development economics - social capital - agricultural development - rural development - innovations - africa south of sahara - institutional economics - congo democratic republic - agriculture - social networks - economic development

In this thesis, I show that social capital has an important role in the evaluation of development initiatives targeting agricultural innovation. Social capital and agricultural innovation are naturally linked from an innovation system perspective in which innovations result from the integration of knowledge from various actors and stakeholders. In chapter 1, I identify the three research questions upon which this thesis is based. First, how are social capital and agricultural innovation related? Second, can development initiatives increase agricultural innovation by building social capital? Third, does the initial level of social capital increase the success of these development initiatives in enhancing agricultural innovation? These question mainly relate to the increasing number of policies, programs and project that include beneficiaries in the design, management and decision making process.

In chapter 2, I elaborate on the main concepts underlying this thesis including social capital, how it relates to development initiatives in the agricultural sector, and how it can be measured. I broadly define social capital as the participation of individuals in formal and informal networks, the norms that define these networks and the trust these individuals have within and outside these networks. Participation in networks is structural social capital, whereas norms and trust within and between these networks is cognitive social capital. I distinguish four dimensions of social capital: structural bonding, structural bridging, cognitive bonding and cognitive bridging. In this thesis bonding and bridging social capital is akin to social capital inside and outside the village. Agricultural innovation is defined in terms of improved land and crop management practices, an important area of agricultural innovation for small scale producers.

In chapter 3 till 7, I empirically investigate the relationships between social capital, agricultural innovation and two types of development initiatives. The first initiative is the implementation of agricultural research through the Integrated Agricultural Research for Development (IAR4D) approach. IAR4D was adopted by the Sub Saharan African Challenge Program (SSA CP) and implemented in eight different countries. The core of this approach is the development of Innovation Platforms (IPs), which can be described as an informal coalition and alliance of conventional agricultural research and development actors. Using the semi experimental data collected in this context, I could investigate the important role of social capital in different contexts. The second type of initiative is implementation of sustainable certification schemes through group-based experimental learning approaches. I investigate four sustainable coffee projects in Vietnam, of which two adopted the interactive Farmer Field School training approach. The data of these four projects allow me to verify some of the conclusions in a different context and for a different development initiative.

In chapter 3, I use baseline data from the IAR4D initiative to explore the association between different forms of social capital and uptake of various agricultural innovations, for a sample of 2500 households in seven countries in SSA. I find that structural bridging social capital is associated with more extensive adoption of agricultural innovations. This result is true for the pooled model as well as for four of the seven country models. This form of social capital captures agriculture-related links creating access to knowledge and resources and is considered an important dimension of economic development. I find a negative association between cognitive bonding social capital and the innovation index. This finding could represent a potentially harmful side of social capital in terms of agricultural innovation.

In chapter 4, I investigate the impact of IAR4D on social capital. I narrow my focus on the border region between Rwanda, Uganda and the DRC. Because the SSA CP data set consist of randomized data of participating and non-participating villages, before and two years after implementation, I can investigate the impact of the program. Many participatory projects in rural Africa are efforts to enhance development indirectly by promoting cooperation in formal or informal networks, and by encouraging trust and norms of behaviour towards mutually beneficial action. But it remains unclear whether external interventions can actually influence social capital, especially in the short term. I show that IAR4D has had a positive impact on structural bridging social capital in DRC and Uganda. There was no impact on structural bridging social capital in Rwanda, or on the other dimensions of social capital. Finally, I showed that traditional agricultural extension has been less successful in increasing structural social capital than IAR4D.

In chapter 5, I use data from a survey I conducted among IP coordinators to measure the extent to which IPs were implemented according to the principles of IAR4D across the three sub regions. Linking these data to the main survey data, I find that the extent to which IPs were implemented according to IAR4D principles is associated with the success of IAR4D in increasing the level of household food security, although not through increased adoption of agricultural innovation or increased levels of social capital at household level. Looking at the sub-components of these principles, especially involvement of IP stakeholder is crucial. Tentative results suggest that this involvement is higher in communities with a higher level of education, a higher percentage of female headed households, and a higher level of village social capital.

In chapter 6, I analyse how different indicators used to represent social capital are related in the border region between Rwanda, Uganda and the DRC. I focus on the relationship between various indicators of trust, an important component of cognitive social capital, and group membership, an important component of structural social capital. The indicators used are based on questions I added to the follow up survey of the SSA CP in 2010. I find that different indicators of trust and group membership cannot be empirically captured by an overarching social capital factor, and are not even necessarily associated to each other.

In chapter 7, I present evidence that the relationship between social capital and agricultural innovation is not only evident for the IAR4D approach, but also for a different development initiative in a different context: sustainable coffee certification in Vietnam. I use data collected among 240 randomly selected project participants and 150 comparable farmers that did not participate in the projects. I focus on the role of bonding and bridging cognitive social capital, defined as trust. I find a significant positive relation between trust and the uptake of sustainable agricultural training practices. This relationship mostly results from high levels of bridging trust, and is even higher in combination with high levels of bonding trust. I also find tentative evidence that participation in the sustainable coffee projects positively influenced bonding trust in one project whereas it negatively influenced bridging trust in another project.

In chapter 8, I give an overview of the three main findings. First, social capital is associated with agricultural innovation. Second, development initiatives can influence social capital. Third, the existing level of social capital is associated with the success of development interventions. However, the effect was not necessarily positive and depends greatly on the dimension of social capital.

I also present several implications for policy. First, stimulating social capital, especially bridging social capital, may be a natural leverage point for policy makers to promote agricultural development. Second, increased levels of social capital can indeed be an outcome of development initiatives, either intentionally or not. At the same time, I show that this impact requires specific efforts and is not necessarily positive. The third implication is that social capital matters for the success of certain development initiatives, either as a source of heterogeneous implementation or impact. Fourth, it is vital to take into account the multi-dimensional nature of social capital and the fact that these dimensions might have different relations to agricultural innovation and development initiatives. Combined these implications mean that indicators of social capital should be included in the design and evaluation of agriculture-related development initiatives.

Finally, I give suggestion for future research. First, to further unravel the chains of causation between different dimensions of social capital, agricultural innovation, and development initiatives. Second, to validate the indicators and indices of social capital using experimental games, more advanced survey questions, or better embedding them in existing theories. A third area of future is to advance in the measurement of innovation as a truly interactive and participatory process. Fourth, to address whether the importance of social capital, as a catalyst for success or as an outcome variable, depends on the nature of the development initiatives or the context in which it is implemented. Finally, research yet has to address the long-run effect of development initiatives on social capital.

Tailoring agroforestry technologies to the diversity of Rwandan smallholder agriculture
Bucagu, C. - \ 2013
Wageningen University. Promotor(en): Ken Giller, co-promotor(en): Mark van Wijk; B. Vanlauwe. - Wageningen : Wageningen University - ISBN 9789461733658 - 252
agroforestry - voedselzekerheid - landbouw - kleine landbouwbedrijven - voedselproductie - bedrijfssystemen - kunstmeststoffen - afrika ten zuiden van de sahara - food security - agriculture - small farms - food production - farming systems - fertilizers - africa south of sahara

Keywords: food security, biophysical and socioeconomic conditions, farmer resource groups, productivity, economic evaluation, scenario analysis

Smallholder livelihoods in sub-Saharan Africa(SSA) are constrained by a number of factors that limit food production and thereby threaten food security. Soil fertility is one of the major factors explaining the decrease in per capita food production in SSA. Nutrient deficiencies in particular N and P severely limit agricultural production in many regions in the tropics. Supply of adequate amounts of nutrients throughfertiliserapplication is therefore a prerequisite to balance soil fertility budgets and to boost food production. However, mineral fertilisers are not accessible to the large majority of smallholder farmers. Farmyard manure, an important source of organic fertiliser for smallholder farmers, is available at limited quantities due to low livestock densities in many regions, for example Rwanda. Agroforestry, a low-input technology, was shown to contribute to the enhancement of food production while ensuring sustainability in sub-Saharan Africa.Agroforestry may contribute to soil fertility by increasing nutrient availability and providing other various benefits and services. However, to be successful agroforestry technologies need to match the characteristics of different smallholder farming systems, like for example soil fertility status, socioeconomic status and farmer management. These factors are rarely studied in an integrated manner.

This thesis aims to understand and characterise different farming systems, evaluate the potential for the most promising agroforestry practices and suggest the most suitable agroforestry recommendations for different farming systems in targeted agro-ecological zones of Rwanda. The approach combined characterization of farming systems, participatory tree testing, farmer’s evaluations of technologies, and scenario and trade-off analyses in two agro-ecological zones: Central Plateau (moderate altitude) and Buberuka (high altitude zone). Two locations, Simbi and Kageyo sectors were selected as representative study sites. Wealth ranking techniques allowed the identification of three farm resource groups (RGs). Though three farmer classes were identified in the two locations and referred as RG 1, RG 2 and RG 3 respectively, farmer classes were unique to each location. Averaged over sampled villages, 76% of all households belong to RG 1 class in Simbi versus 67% in Kageyo. This least resourced group with on average 0.20 ha of land and with 1 goat wasthe most vulnerable farmer groupin terms of food security (20 to 25% protein deficient).RG 2 (9 to 31%) was intermediate between RG 1 and RG 3. RG 3 (2 to 7 %) was the wealthiest (1 to 3 ha, 2 or more cattle) and food-secure for at least 10 months. Soil nutrient balances were negative in most farms due to small amounts of nutrients applied, which did not compensate for nutrient removal during harvest. From an agroforestry perspective, Simbi contrasted with Kageyo in tree diversity and density but tree niches and management were similar between the locations. The main agroforestry species may becategorisedinto three classes including timber, legume and fruit tree species based on the main functions. The results clearly indicated the need to improve soil fertility and food production using integrated soil fertility approaches that promote a combined use of agroforestry resources and other fertiliser sources to replenish the soil nutrients and improve the efficiency and cost effectiveness of inputs use at farm level.

Experiments evaluated the potential effects of agroforestry species on production within different farming systems. Tephrosia species were tested as a source of mulch in coffee plantations in the Central Plateau agro-ecological zone. Application of Tephrosia mulch resulted in higher biomass and better economic returns when established in coffee fields, particularly when Tephrosiamulch was combined with NPK. Application of prunings of Calliandra increased maize productivity, net returns and the ratio between gross margin and costs of inputs on all farms except the richest farms. This positive effect of Calliandra was larger in Kageyo than in Simbi. The effect was even more pronounced with P application. The results indicated that fields responded differently within farms, and significant differences between locations were present.

The assessment of fodder availability within different farming systems revealed that animal feeds are widely diversified, with Pennisetum being largely used in wealthier farms (RG 3), while RG 1 farmers use larger quantities of marshland-herbs and crop residues.There was a strong variation in seasonal feed availability. Napier and Calliandra were more available during the wet season, while banana pseudo-stems were used more in the dry seasons. Quantification of the year-round fodder availability showed that RG 1 farmers are unable to keep a cow, while RG 2 and RG 3 could keep local or improved cows under specific scenarios. Biophysical (rainfall, field type) and socio-economic conditions (wealth status) as well as farmer preferences were factors influencing the choice and performance of agroforestry technologies. The study recommends revisiting current agroforestry research policies and taking into account farmer’s preferences as priorities in the agroforestry research agenda.

Implementation of access and benefit sharing policies in Sub-Sahara Africa: inventory, analysis and proposals
Brink, M. - \ 2013
Ministerie van EL&I - 47
genetische bronnen van plantensoorten - wetgeving - regelingen - belemmeringen - germplasm uitwisseling - afrika ten zuiden van de sahara - Nederland - plant genetic resources - legislation - regulations - disincentives - germplasm exchange - africa south of sahara - Netherlands
Today, individuals, companies and institutes seeking access to genetic resources have to comply with rules and regulations set by national governments, based to a varying extent on the international agreements mentioned above. As each country is following its own interpretations and procedures, this has led to a complex situation, and sometimes even a feeling that in some countries it is not worth the effort anymore to seek access to genetic resources. Therefore, a project was initiated in 2012 to make an inventory of Access and Benefit-Sharing regulations and their implementation in selected countries in Sub-Sahara Africa, to analyse shortcomings and identify options for improvement, while at the same time establishing a discussion platform between and with policy makers in Sub-Sahara Africa and contributing to trust building between African countries and the Netherlands as the basis for substantial improvements in the exchange of germplasm and the fair and equitable benefit-sharing between the parties involved.
Seed systems and intellectual property rights: an inventory from five sub Saharan African Countries
Mahop, M.T. ; Jonge, B. de; Munyi, P. - \ 2013
Ministerie van EL&I - 79
kwekersrecht - intellectuele eigendomsrechten - genetische bronnen van plantensoorten - ontwikkelingslanden - wetgeving - afrika ten zuiden van de sahara - voedselzekerheid - Nederland - breeders' rights - intellectual property rights - plant genetic resources - developing countries - legislation - africa south of sahara - food security - Netherlands
Many developing countries are in the process of developing or updating their national Intellectual Property Rights (IPRs) systems in order to adhere to international agreements. With respect to the agricultural sector in developing countries, the importance of implementing a Plant Variety Protection (PVP) system that suits national and local needs and conditions is of utmost importance. The challenge for developing countries is to create an IPR system that suits both their commercial, national food security, and smallholder farmers’ interests. This report aims to assist in that endeavour by analysing the current status of IPR legislation and regulations regarding seed in five African countries: Burkina Faso, Kenya, Rwanda, Tanzania and Uganda; and the international and regional IPR organisations that encompass them: in particular OAPI and ARIPO. In addition, we investigate the possibilities for, and examples of, a PVP system that creates different levels of protection in order to fit the needs and characteristics of the various seed systems that exist in a given country.
Africa Soil Profiles Database, Version 1.1. A compilation of georeferenced and standardised legacy soil profile data for Sub-Saharan Africa (with dataset). Africa Soil Information Service (AfSIS) project.
Leenaars, J.G.B. - \ 2013
Wageningen : ISRIC - World Soil Information (ISRIC report 2013/03) - 160
bodemprofielen - databanken - bodem - bodemkarteringen - cartografie - georeferentie - afrika ten zuiden van de sahara - soil profiles - databases - soil - soil surveys - mapping - georeference - africa south of sahara
Sustainable agricultural intensification in Sub-Saharan Africa : design of an assessment tool
Verzandvoort, S.J.E. ; Beek, C.L. ; Conijn, J.G. ; Froebrich, J. ; Jansen, H.C. ; Noij, I.G.A.M. ; Roest, C.W.J. ; Vreke, J. ; Mansfeld, M.J.M. van - \ 2012
Wageningen : Alterra, Wageningen-UR (Alterra-report 2352) - 62
landbouwproductie - duurzame landbouw - duurzaam bodemgebruik - gewasopbrengst - waterbeheer - voedingsstoffenbehoeften - voedselzekerheid - afrika ten zuiden van de sahara - agricultural production - sustainable agriculture - sustainable land use - crop yield - water management - nutrient requirements - food security - africa south of sahara
The demand for agricultural products (food, feed, fibre, and biomass for other purposes) produced in Sub-Saharan Africa (SSA) will increase for the coming decades. In addition, the global climate change will largely impact on the agricultural sector in Sub-Saharan Africa. Major challenges for the agricultural sector in SSA are that agricultural production systems depend on resources that are for a large part non-renewable, and that the current agricultural practices in SSA are major contributors to environmental degradation. The Government of the Netherlands addresses food security and sustainable agricultural production in Sub-Saharan Africa. In order to support this process, the Ministry of EL&I has asked for ‘a concept’ to evaluate options for agricultural developments, which are aimed at increasing productivity and improving livelihoods, whilst safeguarding or improving ecosystems. This report presents analyses of yield gaps in Africa, nutrient use and requirements for crop land, and of fresh water production and crop evapotranspiration. The yield gap analysis was based on spatial databases and simulations of potential (irrigated) and water-limited maize yields with a crop growth model. The yield gap in Africa varies largely, ranging from 5 to 60%. The potential improvement for land productivity is large (up to 7 times the actual production levels), even without the help of irrigation. The analysis of nutrient use and requirements for cropland in Africa showed that closing the yield gap requires a higher N and P availability to crops. The analysis of the fresh water production per capita and evapotranspiration from cropland revealed that changes in cropland management, e.g. targeted to increase crop yields and evapotranspiration, can have a dramatic effect on fresh water production and may call for cropping systems that are efficient in water use. From a water use perspective the intensification of agriculture should be assessed at the regional (river basin) level, taking account of the spatial position of the country with respect to water-stressed basins. In the allocation of water resources, priority should be given to the areas where the highest return on water resources can be achieved in terms of types of water use or production systems. The report presents a tool to presented to evaluate strategic plans for the development of agriculture to increase food security in Sub-Saharan Africa. The tool can assist in identifying and evaluating alternative strategies for agricultural intensification in a participatory process. Apart from the Ministry of EL&I, other potential actors and stakeholders in such a process are the Dutch embassies in the pilot countries, governmental planning agencies, the private sector (local and foreign investors), NGOs (local and international NGOs), and knowledge institutes.
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 - 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
New Alliances for Tourism, Conservation and Development in Eastern and Southern Africa
Duim, R. van der; Meyer, D. ; Saarinen, J. ; Zellmer, K. - \ 2011
Delft : Eburon - ISBN 9789059725423 - 210
duurzaam tourisme - ontwikkeling van toerisme - toeristenindustrie - economische ontwikkeling - natuurbescherming - maatschappelijke betrokkenheid - afrika ten zuiden van de sahara - kenya - uganda - botswana - namibië - zuid-afrika - mozambique - zanzibar - sustainable tourism - tourism development - tourist industry - economic development - nature conservation - community involvement - africa south of sahara - namibia - south africa
This book introduces and discusses new alliances related to the growth of tourism in Sub-Saharan Africa. The private sector is increasingly involved in inter-sectoral alliances to both capitalise on the growing tourism industry and contribute to wider economic development in the destinations. The first three chapters of this book discuss representative cases of such alliances in Mozambique, Zanzibar and Uganda. The chapters that follow examine evidence of growth in partnerships between public, private and third-sector organisations in tourism, conservation and development. These illustrate the variety of emerging partnerships and some of their consequences, by means of case studies from Kenya, Uganda, Botswana, Namibia and South Africa.
Long-term effects of conservation soil management in Saria, Burkina Faso, West Africa
Zacharie, Z. - \ 2011
Wageningen University. Promotor(en): Leo Stroosnijder, co-promotor(en): A. Mando; B. Ouattara. - [S.l.] : S.n. - ISBN 9789085858362 - 142
bodembeheer - grondbewerking gericht op bodemconservering - bodemfauna - bodemeigenschappen - sorghum - rotaties - veldwaterbalans - afrika ten zuiden van de sahara - soil management - conservation tillage - soil fauna - soil properties - rotations - field water balance - africa south of sahara

The negative degradation spiral that currently leads to deteriorating soil properties in African drylands is a serious problem that limits food production and threatensthe livelihoods of the people. Nutrient depletion and water and wind erosion are the main factors in soil degradation in Africa. This thesis describes field research conducted from 2006 through 2008 to assess how changes in physical and hydrological soil properties, induced by differences in land management and macro-faunal biodiversity determine water and nitrogen use efficiencies in Burkina Faso. The methodology involved systematic soil sampling of selected treatments (including a fallow control) coupled with macro-fauna identification. Measurements were used to generate information on the effect of the long-term land management practices on soil properties and the different terms of the field water balance. Crop sampling (leaves, stem and grains) allowed determination of plant nutrient uptake and calculation of water and nitrogen use efficiency. Differences in soil properties between treatments were smaller than expected after so many years of applying the same soil management practice. Results indicate that long-term permanent cultivation result in a decrease in the quality of most soil properties when compared with the fallow. We also found that there are clear benefits from inclusion of cowpea in a rotation system due to its N fixation and deeper root system. Regarding soil fauna, long-term application of the same soil management practices resulted in specialization of the food type for the macro-fauna leading to less fauna diversity. Also, more diverse and abundant macro-fauna was discovered under superficially tilled plots compared to tractor plowed plots. The contribution of the soil fauna to aggregate building depends on the amount and type of organic material available to the fauna as well as the soil management regime. In spite of the amount of applied organic amendments used in our trials, the C-stock in the soil has decreased at a rate of 0.25 % per year, perhaps limiting macro-fauna activity. The 3-year average of the green water use efficiency (ratio T/P) was only 14% and the crop yield was also low due to less than optimal crop management. Results further suggest that systematic, rather than strategically timed, N applications (organic and/or mineral) are likely to lead to N losses. Synchronizing N fertilizer application with crop-N demand and accounting for residual Nitrogen will lead to higher N fertilizer use efficiency. Soil management practices, crop selection and fertilizer regime can have positive or negative impacts on water and nutrient use efficiency. Practices with positive impact should be encouraged in order to increase crop productivity and improve food security in Burkina Faso.

AIDS and Rural Livelihoods. Dynamics and Diversity in Sub-Saharan Africa
Niehof, Anke ; Rugalema, G. ; Gillespie, S. - \ 2010
London : Earthscan - ISBN 9781849711265 - 234
ontwikkelingsstudies - acquired immune deficiency syndrome - humane ziekten - hiv-infecties - volksgezondheid - platteland - plattelandsbevolking - sociale economie - rurale sociologie - economische aspecten - afrika ten zuiden van de sahara - landbouwhuishoudens - development studies - human diseases - hiv infections - public health - rural areas - rural population - socioeconomics - rural sociology - economic aspects - africa south of sahara - agricultural households
HIV and AIDS continue to devastate the livelihoods of millions of Africans and represent the major public health challenge in many countries. More people die of AIDS each day than from wars, famine and floods combined, while an orphaned generation of children must be provided for. Yet despite millions of dollars of aid and research, there has previously been little detailed on-the-ground analysis of the long-term impact on rural people. This book brings together recent evidence on HIV/AIDS impacts on rural households, livelihoods, and agricultural practice in sub-Saharan Africa. There is particular emphasis on the role of women in affected households. The book presents micro-level information collected by original empirical research in a range of African countries, and shows how well-grounded conclusions on trends and major problems can then be addressed by policies. It is shown that HIV/AIDS impacts are more diverse than we know (and not always negative) on the basis of cumulative evidence so far.
Co-managing complex social-ecological systems in Tanzania : the case of Lake Jipe wetland
Mahonge, C.P.I. - \ 2010
Wageningen University. Promotor(en): Arthur Mol, co-promotor(en): Simon Bush. - [S.l. : S.n. - ISBN 9789085856528 - 203
milieubeleid - ecologie - wetlands - hulpbronnenbeheer - natuurlijke hulpbronnen - sociale participatie - bedrijfsvoering - visserij - landbouwproductie - veehouderij - pastoralisme - tanzania - afrika ten zuiden van de sahara - bewonersparticipatie - environmental policy - ecology - resource management - natural resources - social participation - management - fisheries - agricultural production - livestock farming - pastoralism - africa south of sahara - community participation
It has been conventional among co-management scientists to view social-ecological systems and actors and institutions found in these systems monolithically. Such a view is simplistic and conceals the complex nature of social-ecological systems and associated institutions and actors. In essence, a social-ecological system is a complex system comprised of multiple, diverse and dynamic social-ecological units, players and rules. This thesis entitled Co-managing complex social-ecological systems unveils the aforementioned complexity in which Lake Jipe wetland in Tanzania is the central case. This case depicts intra-, inter- and cross-scale interactions among multiple and dynamic institutions, actors and ecological systems at different dimensions of space and time. While some candidates of actors and institutions play separate roles, others play interdependent and linking roles across the multiple sectoral social-ecological units. The thesis introduces the layering concept of institutions and actors in three sectoral arrangements at Lake Jipe. It argues that not only do the institutions and actors found in social-ecological systems operate next to one another but also they work interdependently. This concept extends the existing knowledge of co-management practitioners and scholars about the diversity and complexity of inter-linked human-environment systems that traverse the current monolithic view and conceptual boundaries. As such, the thesis avoids a simplistic monolithic approach that may end up in superficial treatment of complex environmental management problem and sheds light on how to study and approach intricate social-ecological systems using models that recognise the diversities of these intricate systems.
Single women, land and livelihood vulnerability in an communal area in Zimbabwe
Paradza, G.G. - \ 2010
Wageningen : Wageningen Academic Publishers (AWLAE series no. 9) - ISBN 9789086861460 - 295
ontwikkelingsstudies - vrouwen - plattelandsvrouwen - positie van de vrouw - huwelijk - gezinnen - gezinsstructuur - gezamenlijk eigendom - gemeenschappelijke weidegronden - eigendom - toegang - toegangsrecht - zimbabwe - afrika ten zuiden van de sahara - middelen van bestaan - strategieën voor levensonderhoud - alleenstaanden - burgerlijke staat - development studies - women - rural women - woman's status - marriage - families - family structure - coownership - common lands - ownership - access - right of access - africa south of sahara - livelihoods - livelihood strategies - single persons - civil status
Single women, land and livelihood vulnerability in an communal area in Zimbabwe
Paradza, G.G. - \ 2010
Wageningen University. Promotor(en): Han van Dijk, co-promotor(en): B. O'Laughlin; J. Stewart. - [S.l. : S.n. - ISBN 9789085854746 - 307
development studies - women - rural women - woman's status - marriage - families - family structure - coownership - common lands - ownership - common property resources - farming - rural areas - land ownership - access - right of access - zimbabwe - africa south of sahara - livelihoods - livelihood strategies - single persons - civil status - ontwikkelingsstudies - vrouwen - plattelandsvrouwen - positie van de vrouw - huwelijk - gezinnen - gezinsstructuur - gezamenlijk eigendom - gemeenschappelijke weidegronden - eigendom - gemeenschappelijk bezit - landbouw bedrijven - platteland - grondeigendom - toegang - toegangsrecht - afrika ten zuiden van de sahara - middelen van bestaan - strategieën voor levensonderhoud - alleenstaanden - burgerlijke staat
Soil macrofauna functional groups and their effects on soil structure, as related to agricultural management practices across agroecological zones of Sub-Saharan Africa
Ayuke, F.O. - \ 2010
Wageningen University. Promotor(en): Lijbert Brussaard, co-promotor(en): Mirjam Pulleman; B. Vanlauwe; J. Six. - [S.l. : S.n. - ISBN 9789085856870 - 202
agrarische bedrijfsvoering - gewasteelt - bodemstructuur - wormhoopjes - termietenheuvels - mierenhopen - agro-ecologische zones - isoptera - aardwormen - afrika ten zuiden van de sahara - kenya - macrofauna - farm management - crop management - soil structure - worm casts - termitaria - ant hills - agroecological zones - earthworms - africa south of sahara
This study aimed at understanding the effects of crop management practices on soil macrofauna and the links with soil aggregation and soil organic matter dynamics, which is key to the improvement of infertile or degrading soils in Sub-Sahara Africa. Soil macrofauna, especially earthworms and termites, are important components of the soil ecosystem and, as ecosystem engineers, they influence the formation and maintenance of soil structure and regulate soil processes, such as organic matter decomposition and nutrient dynamics. In comparison with natural systems, earthworm and termite diversity and abundance were low in fallow, high soil-carbon (C) and low soil-C arable treatments in 12 long-term trial fields across the sub-humid to semi-arid tropical zones in Eastern and Western Africa. Continuous crop production had significant negative effects on earthworm diversity, but little effect on termite diversity, as compared to long-term fallow. Agricultural management resulting in high soil C increased earthworm and termite diversity as compared to low-C soil.Long-term application of manure in combination with fertilizer resulted in higher earthworm diversity and biomass, associated with improved soil aggregation and enhanced C and N stabilization within this more stable soil structure. These practices therefore result in the dual benefits of improving soil physical and chemical properties. A micromorphological study of undisturbed soil thin sections showed that fallowing, conservation tillage plus residue application (in East Africa) and hand-hoeing plus manure (in West Africa) enhanced biogenic soil structure formation, resulting in a well developed soil structure and a continuous pore system characterized by many faunal channels. In contrast,intensive tillage and absence of organic inputs resulted in soil with less biogenic soil structural features. Farmers in Nyabeda, West-Kenya, were aware of the activities and nesting habits of termites, but 90% percent of the farmers perceived termites as pests.This study has shown that the soil macrofauna, especially earthworms, and, to a lesser extent termites, are important drivers of stable soil aggregation in Sub-Saharan agroecosystems, with beneficial effects on soil physical and chemical properties. However, their beneficial impact on soil aggregation is reduced with increasing management intensity and associated soil disturbance due to cultivation. This knowledge is important in designing agricultural management systems aimed at increasing long-term soil fertility in Sub-Saharan Africa.
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