{"id":11504,"date":"2026-04-13T11:21:12","date_gmt":"2026-04-13T11:21:12","guid":{"rendered":"https:\/\/www.proefschriftmaken.nl\/portfolio\/wilson-wilson\/"},"modified":"2026-04-22T14:41:50","modified_gmt":"2026-04-22T14:41:50","slug":"wilson-wilson","status":"publish","type":"us_portfolio","link":"https:\/\/www.proefschriftmaken.nl\/en\/portfolio\/wilson-wilson\/","title":{"rendered":"Wilson Wilson"},"content":{"rendered":"","protected":false},"excerpt":{"rendered":"","protected":false},"author":8,"featured_media":12050,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_acf_changed":false,"footnotes":""},"us_portfolio_category":[45],"class_list":["post-11504","us_portfolio","type-us_portfolio","status-publish","has-post-thumbnail","hentry","us_portfolio_category-new-template"],"acf":{"naam_van_het_proefschift":"The role of the integrated soybean-maize-chicken value chains in sustainable food systems in the Southern Highlands of Tanzania","samenvatting":"Er is geen Nederlandse samenvatting beschikbaar. De Engelse samenvatting vind je <a href=\"https:\/\/www.proefschriftmaken.nl\/en\/portfolio\/wilson-wilson\/\">hier<\/a>.","summary":"The increasing human population in sub-Saharan Africa (SSA) implies that the demand for major cereals will increase three-fold while that of animal-sourced food (ASF) will double by the year 2050. Although initiatives are taking place to achieve SDG2 (zero hunger), food insecurity and micronutrient deficiencies are still alarming in SSA. Tanzania is among the SSA countries experiencing food insecurity due to high rates of malnutrition in many forms, largely attributed to a lack of dietary diversity among disadvantaged urban and rural households. Tanzania is a typical example of SSA country facing such challenges where limited dietary diversity has been reported among disadvantaged urban and rural poor households. Surprisingly, the breadbasket regions important for food production in Tanzania have high rates of undernutrition and micronutrient deficiency, partly due to limited dietary diversity. This thesis focused on exploring the potential of soybean-maize-chicken value chains to support the sustainable production of diversified diets and identify important entry points for value chain integration in the Southern highland zone of Tanzania.\n\nThe work presented in this thesis was part of the N2Africa project implemented in the Southern highlands of Tanzania between 2014 and 2018, aimed to improve household nutrition and cash income and to enhance soil fertility. Building from the N2Africa project findings, further research findings presented in this thesis was part of the \u201cThe Missing Middle project: Food system transformation pathways to link actions at multiple levels to Sustainable Development Goals (SDGs) particularly the SDG 2, 12, 13 and 15 in Tanzania\u201d funded by NWO-WOTRO research program\u201d.\n\nIn Chapter 2, I employed fuzzy cognitive mapping (FCM) to understand the current soybean, maize, and chicken value chains, highlight stakeholder relationships, and identified entry points for value chain integration to support nutritious diets in three regions in the Southern highlands of Tanzania. The fuzzy cognitive maps were constructed based on information gathered during household interviews followed by a participatory workshop with stakeholders involved in the three value chains. The study revealed the importance of networks of integrated value chains in domestic markets, whereby soybean-maize-chicken value chains are interconnected particularly at smallholder farming systems and at processing facilities. Chicken feed was an important entry point for integrating the three value chains, as maize and soybean meal are chickens' main sources of energy and proteins. Unlike maize, the utilization of soybean in chicken feed was very low, mainly due to inadequate processing of soybean grain into meal. As a result, the soybean grain produced is primarily exported to neighbouring countries for further processing, and soybean meal is imported at relatively high prices. The findings in Chapter 2 proposed enhancing local sourcing and adequate processing of soybean coupled with strengthening the integration of smallholder farmers with other soybean-maize-chicken value chain actors to improve access to nutritious food for people.\n\nIn Chapter 3, I conducted a cross-sectional survey to understand chicken farming diversity and explore the intensification gradient in the production systems in urban and rural areas in the Iringa region. In the next step, I employed a problem tree analysis based on the survey data to classify the underlying constraints and their interrelations, and to identify common root causes, based on which we propose practical solutions to improve chicken production along the intensification gradient identified in urban and rural. This study is the first to explore the diversity of chicken farming and the underlying production constraints based on the subdivision of the production systems. The subdivision of poultry systems was refined by adding the size of the flocks to highlight variations in the scale of operations.\n\nThe findings in Chapter 3 show that the degree of intensification of chicken production systems in the Iringa region was increasing with the number of improved crossbred and exotic chickens raised under the medium-large scale intensive systems, that were fed with homemade and\/or commercial feeds in both urban and rural locations. Furthermore, about 30% of households had more than one breed and\/or rearing system combination. The subdivision in production systems and the problem tree analysis in Chapter 3 revealed different constraints limiting chicken production depending on the types which opens the door to propose relevant packages for improving the production of meat and eggs for households and other consumers. Despite a greater management input, more intensive systems reported more disease problems implying that there should be training on improved housing and veterinary measures, particularly for the farmers intensifying to the medium to large scale production systems. Apart from the existence of chicken diseases in all the systems, the development of the medium-large scale systems is highly constrained by a limited supply of one-day-old chicks and theft, while the intensification of small-scale systems is constrained by limited access to quality feeds, vaccines and medicines, capital, and reliable output market, partly associated with lack of farmer organization. There is therefore a need for institutional support to organize producers into groups and\/or cooperatives with an emphasis on training them on proper management, low-cost feed processing, group marketing and large-scale rearing of chickens. The enterprise development might be the most promising business model for the growth of smallholder chicken farming since farmers have more freedom in farm management and decision-making while they will be linked with the input suppliers and output markets to ensure a viable and profitable business.\n\nIn Chapter 4, I present the findings on feed gap analysis, where we explored the current feed gap and how the feed gap can be closed by comparing the actual feed quantity and quality supplied to dual-purpose chicken with the recommended standards. This study is the first to explore the actual production and feed quantity and quality (status quo) in the poultry industry in Tanzania unlike other studies conducted under a controlled experimental design. The findings presented in Chapter 4 highlight the need for a stronger focus on feeding strategies and ensuring the availability of suitable and safe feed formulations. The study was based on robust methods combining surveys, physical measurements of chicken and eggs, sampling of feed and laboratory analysis on micronutrient content and mycotoxin contamination. In line with the TLMP, the chapter revealed a large gap in current chicken production and highlighted the importance of closing feed gaps (both quantity and quality) to meet the increasing demand for chicken meat and eggs. The quality issues are not only related to low crude protein and essential amino acids in chicken feed rations but also to aflatoxin levels pointing at potential animal and human health risks.\n\nIn Chapter 5, I assessed land requirements to produce sufficient food of adequate nutritional quality for the current and the anticipated doubled population of the Iringa region by 2050 based on macro secondary data, and micro primary data collected in the region between 2018-2020. The actual and potential yield of the food crops grown in the region were extracted from the Yield Gap Atlas, a global open-access database. The findings of this Chapter revealed that with the actual yields for crops and poultry and a doubling in population size by the year 2050, the land requirement must increase more than two folds to produce sufficient food and feed. When only utilising suitable land with the actual yields leads to food-feed competition in most scenarios and with the increasing population, food export will be strongly reduced or no longer possible. To meet the increasing demand for food, the present study strongly recommends focusing on sustainable intensification options aiming to reduce the yield gaps in the region. Otherwise, with the current yield, producing sufficient food and feed will not be feasible without further expanding agricultural production in suitable and non-suitable land. Especially expanding in unsuitable land would require high investments in irrigation, energy use, labour, fertiliser etc.\n\nTo meet the increasing demand for nutritious food, the present study strongly recommends focusing on sustainable intensification options aiming to reduce the yield gaps in crop and poultry production. Otherwise, with the current yields, producing sufficient food and feed will not be feasible without further expanding agriculture on suitable and non-suitable land. Furthermore, access to poultry products alone will not allow consumers to have a micronutrient-sufficient diet thus more avenues need to be explored especially to increase Vitamin A and Calcium supply, which will also need land to be produced. I hope that the findings from this thesis will inform the decision-makers from regional to national levels to implement sustainable intensification options aiming to reduce yield gaps and further expansion of agricultural land to produce sufficient diverse food for the current and future population.","auteur":"Wilson Wilson","auteur_slug":"wilson-wilson","publicatiedatum":"14 juni 2023","taal":"EN","url_flipbook":"https:\/\/ebook.proefschriftmaken.nl\/ebook\/wilsonwilson?iframe=true","url_download_pdf":"","url_epub":"","ordernummer":"FTP-202604131118","isbn":"978-94-6447-644-6","doi_nummer":"","naam_universiteit":"Wageningen University","afbeeldingen":12050,"naam_student:":"","binnenwerk":"","universiteit":"Wageningen University","cover":"","afwerking":"","cover_afwerking":"","design":""},"_links":{"self":[{"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/us_portfolio\/11504","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/us_portfolio"}],"about":[{"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/types\/us_portfolio"}],"author":[{"embeddable":true,"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/users\/8"}],"replies":[{"embeddable":true,"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/comments?post=11504"}],"version-history":[{"count":1,"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/us_portfolio\/11504\/revisions"}],"predecessor-version":[{"id":11505,"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/us_portfolio\/11504\/revisions\/11505"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/media\/12050"}],"wp:attachment":[{"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/media?parent=11504"}],"wp:term":[{"taxonomy":"us_portfolio_category","embeddable":true,"href":"https:\/\/www.proefschriftmaken.nl\/en\/wp-json\/wp\/v2\/us_portfolio_category?post=11504"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}