Des mesures sur parcelles agroforestières (mélanges d'arbres et de cultures) expérimentales mettent en évidence des productivités exceptionnelles, avec des gains de plus de 30% par rapport à l'assolement de cultures pures. Nous avons mis au point et utilisé un modèle numérique dynamique en 3-D (Hi-sAFe) pour (1) tester si l'intégration spatio-temporelle du partage des ressources (lumière, eau, azote) entre espèces suffit à expliquer cette productivité et (2) évaluer l'impact de différents choix de conception ou de gestion sur cette productivité, à partir d'une compréhension des processus impliqués.Nous avons développé une méthode originale d'analyse des données simulées pour identifier et hiérarchiser les processus déterminant le rendement. Le modèle a été paramétré et calibré sur un système noyer hybride / blé dur situé sur le domaine de Restinclières (Hérault, France). Après une analyse détaillée du fonctionnement de ce système, nous avons exploré par expérimentation virtuelle sa réponse à des choix de conception: (1) traits phénologiques des espèces associées, et (2) densité et disposition des arbres sur la parcelle. Par la richesse de son comportement, Hi-sAFe permet un regard nouveau sur le fonctionnement des systèmes agroforestiers. Il éclaire la complexité du système réel. Nos résultats permettent de proposer une interprétation déterministe du rendement de chaque espèce et de la productivité totale de l'association (Land Equivalent Ratio). L'analyse des expérimentations virtuelles permet de proposer des pistes concrètes pour l'optimisation des systèmes agroforestiers. / Measurements on experimental silvoarable agroforestry plots (mixed tree-crop) showed exceptionally high productivity, with yields more than 30% higher compared to the separate crop and tree systems. We developed a 3-D process-based model (Hi-sAFe) and used it to (1) test if the spatiotemporal integration of resources sharing (light, water, nitrogen) between species could explain this productivity and (2) assess how agroforestry design or management may affect this productivity. We developed a novel method for the analysis of simulated data to identify and sort the processes determining yield by order of importance. The model was parameterized and calibrated on a hybrid walnut / durum wheat located on the Restinclières field (Hérault, France). After a detailed analysis of the functioning of this system, we explored by virtual experiments its response to design choices: (1) phenological traits of associated species, and (2) density and location of trees on the plot. The comprehensiveness of the Hi-sAFe model provides a new insight into the functioning of agroforestry systems. It clarifies the complexity of the real system. Our results put forward a deterministic interpretation of the performance of each species and of the total productivity of the crop-tree association (Land Equivalent Ratio). The analysis of virtual experiments offers practical ways for optimizing agroforestry systems.

La majorité des espèces cultivées en Europe (environ 84 %) nécessitent le service de pollinisation pour produire. Depuis plusieurs années, un important déclin des pollinisateurs est observé. Les populations d’abeilles domestiques, partie intégrante de l’agrobiodiversité, sont des bio-indicateurs sensibles de l’état de l’environnement agricole. Celles-ci sont aujourd’hui affectées par des mortalités importantes. Les interactions entre pesticides et pathogènes sont habituellement évoquées comme causes principales de ces mortalités. Cependant au sein de ces agropaysages, la perte de ressources trophiques en quantité et en diversité contribue également à l’affaiblissement des colonies. La qualité et les quantités de ressources trophiques disponibles dans le paysage influencent également leur activité de ponte et leur dynamique de développement. Au regard de ce contexte, cette thèse vise à analyser les interactions entre différents types de structures paysagères situées dans le département du Gers (32, France) et l’évolution des traits d’histoire de vie des colonies d’abeilles domestiques du genre Apis mellifera L. Elle questionne notamment le rôle de la composante ligneuse dans l’apport de ressources trophiques et ses repercussions sur l’évolution des traits d’histoire de vie. L’approche méthodologique développée consiste (i) en une analyse de l’organisation spatiale des six mosaïques paysagères différenciées par un gradient de présence de ligneux, (ii) en un suivi phénologique des ressources floristiques d’intérêt nectarifère et pollinifère, (iii) en un suivi de la dynamique de développement de 43 colonies observées durant deux ans (2010 et 2011) et (iv) en une analyse des strategies de butinage. Les résultats montrent la présence d’une grande diversité d’espèces floristiques d’intérêt nectarifère et pollinifère en contexte agricole gersois (200). Les ligneux constituent la seule sous-unité fonctionnelle permettant un apport conséquent et pérenne de ressources floristiques, tout au long de la saison en complément des cultures. La composante ligneuse et les surfaces cultivées (Brassica napus et Helianthus annuus) constituent les deux sous-unités les plus mobilisées pour la collecte de nectar. Les ligneux sont particulièrement recherchés au cours des périodes prévernale et vernale (première période) notamment au sein des structures paysagères fermées. La fluctuation des ressources floristiques disponibles impacte plus fortement le développement des colonies au sein des structures paysagères ouvertes que fermées. En effet, sur ces derniers, les ligneux permettent d’atténuer ces impacts notamment en période de disette, rendant les colonies plus résilientes. / Most of the cultivated plants in Europe (84% overall) need pollinators to produce. For several decades, a significant decline in pollinating insects is observed. Honeybees belong to associated agrobiodiversity and are sensitive bio-indicators in agricultural landscapes. They are particularly affected by these losses. Usually, interactions between pesticides and pathogens are seen as the main causes of pollinator populations’ collapse. However, the qualitative and quantitative depletion of food resources in such agricultural landscapes also contribute to the high mortality rates. The spawning activity of the colony’s queen and the metabolic balance of the colony are influenced by the quantity and the quality of plant resources in the landscape. This PhD thesis focuses on the interactions between landscapes structures and honeybees life traits’ evolution in the Gers agricultural department (France). It aims to assess the woody component’s role in supplying trophic resources and its repercussions on the evolution of life traits. The methodology consists (i) in a spatial organization analysis of six landscape mosaics, differentiated by an openess gradient based on the percentage of the woody component cover, (ii) a phenological monitoring of plant resources with pollen and nectar interests, (iii) a monitoring of 43 colonies’ life history traits during two years (2010 and 2011) and (iv) in an analysis of foraging strategies. Results reveal a wide diversity of plant species with nectar and pollen interest in the Gers agricultural context (200). Woody component is the only functional sub-unity which enables a significant and lasting supply of plant resources, during the all season, as additional resources to those of crops. Woody component and cultivated lands (Brassica napus and Helianthus annuus) are the most mobilized sub-unities for nectar gathering. Woody component is particularly looked for in prevernal and vernal periods (first period), above all in closed landscape structures. Variations of available plant resources impact colonies’ development more in open landscape structures than in closed ones. Indeed, in closed landscape structures, woody component enables to reduce consequences, especially in scarcity period, and make colonies more resilient.

Please read the abstract in the dissertation / Dissertation (MSc (Agric))--University of Pretoria, 2001. / Plant Production and Soil Science / unrestricted

The “2015 proceedings” document the contributions of the third and final annual Summer-School Workshop of the “Scientific Cooperation Network on Climate Change Adaptation”, a project within the DAAD program “Welcome to Africa”. The workshop took place on 17-31 May, 2015 at Tharandt campus of the Technische Universität Dresden and at selected locations in the region.:Climate Change Adaptation and Mitigation 1 Methodological Fundamentals of Socio-Economic Climate Change Adaptation Research at the Institute of International Forestry and Forest Products, TU Dresden 2 Climate Change Adaptation in Saxony 4 Historical Path of Forestry and the Role of ‘Ujamaa’ Ideology to Today’s Policy of Community Forest Management in Tanzania 19 Contribution of the National Adaptation Plan of Action Project to Sustainable Livelihoods in North Kordofan State, Sudan 31 Local People’s Perception of Climate Variability Including Their Mitigation and Adaptation Strategies in Mountainous Areas of Uganda 47 Role of Indigenous Knowledge in Traditional Farming System Management under Changing Climate, Sudan 54 Quarterly Climate Change Preparedness Workshop in Arsi Negelle, Ethiopia 63 Impact of Farmer Field Schools in Diffusion of Information about Climate Change in South Kordofan State, Sudan 74 Effects of Climate Change on Traditional Rain-fed Agriculture in Sheikan Locality, North Kordofan State, Sudan 81 Can Rain Water Harvesting Mitigate Flooding Associated with Climate Change in Urban Areas? A Case Study of Jinja Municipality, Uganda 91 Agroforestry, Reforestation, and Climate Change 97 Agroforestry in Reducing Emissions from Deforestation and Forest Degradation (REDD+): Africa, Where Are You? 98 Carbon Sequestration and Greenhouse Gas Emissions in Agroforestry: Summary of Global Data and Implications for Africa 113 Propagation Techniques for Ethiopian Highland Bamboo Yushania alpina in Amhara Region, Banja Districts, North-Western Ethiopia 121 The Performance of GAPAs on Enhancing the Production and Marketing of Gum Arabic Production in West and North Kordofan States, Sudan 131 CHAnces IN Sustainability – Promoting Product Chains of Natural Products in Eastern Africa 132 Biodiversity Conversation and Bioenergy 135 Land Use, Land Cover and Climate Change Impacts on the Bird Community in and around Lake Zeway, Ethiopia 136 African Baobab: Urgent Need for Assessments and Management Approaches for Sustainable Development in Sudan 137 Ecotourism as Alternative Mean of Biodiversity Conservation and Livelihood Improvement of the Local Community 145 The Role of Wood Fuel in Climate Change: A Case of Urban and Rural Areas in Uganda 159 Scientific Cooperation Network on Climate Change Adaptation 169 Network Contact Persons 169

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[pt] Nesse trabalho busca-se perceber a maneira como o movimento desigual do capital que se articula em uma escala global se realiza no e através do local. Para esse exercício a comunidade do Vale Encantado, Alto da Boa Vista – RJ nos seus últimos 10 anos, será o recorte espacial-temporal selecionado. Além de perceber e estudar o desenvolvimento desigual na comunidade, promovido, sobretudo, pela entrada da ONG Abaquar nesta, é parte do problema perceber quais as possibilidades de valorização da prática agroflorestal na produção do espaço da comunidade. Assim sendo, uma abordagem crítica do espaço da comunidade do Vale Encantado é necessária para que ocorra o desvelar das representações desse espaço. A prática da agrofloresta ganha força dentro de um contexto de ressignificação da relação entre sociedade e natureza. Sua prática oferece resistência ao padrão industrial e homogêneo de cultivo e ajuda a conceber outras práticas de cultivo do solo, como o plantio manual, diversificado e sucessional. / [en] This work seeks to understand how the uneven movement of capital which is articulated on a global scale takes place in and through the site. For this exercise the community of Vale Encantado, Alto da Boa Vista - RJ, in his last 10 years, will be the selected space-time frame. In addition to understand and study the uneven development in the community, promoted mainly by the entry of the NGO Abaquar, is part of the problem figure out the recovery possibilities of agroforestry practice in the production of community space. Therefore, a critical approach to the Vale Encantado community space is required to occur the uveiling of the representations of that space. The practice of agroforestry gains strength within a reinterpretation of the context of the relationship between society and nature. His practice offers resistance to industrial and homogeneous pattern of cultivation and helps devise other soil cultivation practices such as manual planting, diverse and succession.

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Les systèmes agroforestiers stockent du carbone dans la biomasse des arbres. Cependant leur intérêt ne se limite pas à ce carbone stocké sous forme de bois. En effet, les arbres produisent de grandes quantités de litières, et apportent également du carbone dans les horizons profonds du sol par la mortalité et l’exsudation racinaire. Or, les sols agricoles, ayant de très faibles teneurs en matière organique, ont un potentiel de stockage en carbone bien plus important que les sols forestiers. A ce jour, il n’existe pratiquement pas de travaux permettant d’avoir une estimation de l’impact des arbres agroforestiers sur le carbone du sol. La plupart des études sont en effet menées sur le stockage de carbone dans la biomasse aérienne des arbres. Une étude a ainsi estimé qu’en climat tempéré et pour des densités comprises entre 50 et 100 arbres/ha, le stockage de carbone serait compris entre 1.5 et 4 tC/ha/an, ce qui est très important comparé au potentiel de stockage d’autres systèmes de culture. On se propose donc dans ce travail de contribuer significativement à la connaissance sur les possibilités de stockage de C dans les sols en agroforesterie. Tout d’abord, nous quantifierons les stocks de C dans les parcelles agroforestières et les comparerons aux témoins agricoles. Nous étudierons également l’hétérogénéité spatiale de ces stocks, sous la ligne d’arbres ou sous la culture intercalaire, et ce à différentes profondeurs. Dans un deuxième temps, nous étudierons les entrées de carbone au sol, notamment via la mortalité racinaire des arbres. Puis, nous étudierons les processus liés à la stabilisation de ce carbone dans les horizons profonds du sol. Enfin, nous chercherons à savoir si l’apport de carbone frais dans les horizons du sol ne pourrait pas entraîner une minéralisation d’une partie du carbone stable du sol, phénomène connu sous le nom du priming effect, et qui pourrait jouer un rôle non négligeable dans le bilan de carbone de ces systèmes. La modélisation sera utilisée afin d’estimer le stockage de carbone sur le long terme. L’étude sera menée dans un contexte de système de culture méditerranéen, sur un site expérimental d’exception. L’analyse mécaniste fournira le cadre conceptuel pour la compréhension de la dynamique du C dans d’autres systèmes agroforestiers à l’avenir. / Agroforestry is a land use type where trees are associated with crops and/or animals within the same field. This agroecosystem could help mitigating climate change, and also contribute to its adaptation. The goal of this thesis was to evaluate the potential of soil organic carbon storage under agroforestry systems. This study was performped at the oldest experimental site in France, a trial supervised by INRA since 1995, but also at farmers' fields. Soil organic carbon stocks were compared between agroforestry and agricultural plots, down to 2 m soil depth. All organic inputs to the soil were quantified (tree roots, leaf litter, crop roots and residues). The stability of additionnal stored carbon was caracterised with soil organic matter fractionation, and soil incubations. A model of soil organic carbon dynamic was described in order to better undrestand this dynamic in agroforestry, especially in deep soil layers. This study revealed the interest and the potential of agroforestry systems in increasing soil organic carbon stocks, with accumulation rates of 0.09 to 0.46 t C ha -1 yr -1. It also reveals the role of tree rows in this storage, and the importance of carbon inputs from root mortality. However, it raises concerns about the stability of this storage.

Agroforestry (AF) or agroforestry innovation (AFI) production has long been and continues to be a component of the mixed farming system of Ethiopian and smallholder farmers worldwide. Interventions continue introducing new or improved management practices, species, and techniques to raise AFI's livelihood and natural resource management contributions. Despite considerable efforts, the adoption of these AFI continues to be limited, as proved by several adoption studies and development efforts. Formal and informal studies were conducted for decades to understand the problems for the low adoption of various AFI. Nevertheless, these studies generated redundant and marginally growing important information as it has weakly altered the course of development approaches and policy regulations. Learning from previous studies, researchers have been requesting more robust studies that help address existing knowledge gaps on adopting AFI. To respond to these calls, this PhD project examined the factors affecting the adoption of AFI by smallholders and Ethiopian farmers as a case study. The project builds upon previous studies to explore the diverse perspectives that influence the adoption of AFI. Literature assessment of recent studies indicated that several factors belonging to farmers and institutions influence the adoption of AFI. Simultaneously, we discovered that some issues were explored frequently (e.g., socioeconomic factors), whereas others (e.g., psychological factors) were largely ignored. Besides, researchers have followed the static assumption (i.e., adopt or non-adopt) and failed to learn the adoption process beyond a one-time decision. Additionally, the studies focused on discrete factors and activities and failed to comprehend the diverse perspectives and factors and their combined effect on eventual AFI adoption. Ultimately, learning from the larger adoption science and previous studies, we developed a comprehensive framework, 'AFI adoption framework' (chapter 4.1), that supports the meaningful assessment of adoption practices and comprehensively discovers factors influencing AFI adoption. The framework encompassed three compartmentalized and yet interlinked components that influence AFI adoption under smallholder contexts. The framework commended both distinct studies for exhaustive elaboration and simultaneously suggested holistic examination. Besides, it recommended minor and major modifications to the research approaches, such as proper treatment of variables in econometric models, incorporation of variables related to the psychological status, and employment of robust tools such as the real-options approach for profitability analysis. Based on this framework, we designed a project and conducted fieldwork in the Amhara region of Ethiopia, a typical smallholder context. We explored the household contexts (i.e., farm level and psychological), system level features, and innovation characteristics influencing smallholders' AFI adoption decisions. It employed mixed conventional and advanced analytical tools comprising content analysis, econometric models, principal component analysis, and financial discounting methods. Advanced methods comprehend process analysis and adoption dynamism. The results from discrete analysis indicated that socioeconomic factors, psychological constructs, system level features, and innovation attributes influence AFI adoption. Regarding innovation characteristics, the different attributes are foundations for undertaking AFI adoption decisions of smallholder farmers. Beyond adopt-non-adopt concepts, we found farmers continuously undertake follow-up adoptions of varying extents such as reduced, maintained, and increased. Based on our query and comparable to existing frameworks, the newly developed 'AFI adoption framework' is more reasonable to meaningfully investigate factors influencing AFI (and agricultural innovations) adoption under smallholder contexts. However, there is a need for precaution while employing the framework to more clearly discern the adoption process and reflect the integration among the factors and activities involved from the development to the adoption of AFI. This dissertation excluded empirical analysis of profitability and holistic assessment due to the voluminous nature of the dissertation.:PREFACE ii ACKNOWLEDGEMENTS iii SUMMARY iv ZUSAMMENFASSUNG vi LIST OF FIGURES ix LIST OF TABLES xi ACRONYMS xi 1. INTRODUCTION 1 1.1. Agroforestry in Ethiopia 1 1.2. Problem statement 4 1.3. Objectives and research questions 6 1.4. Scope of the study 7 1.5. Dissertation structure 8 2. CONCEPTUAL FRAMEWORK 11 2.1. The adoption concept 11 2.2. Theoretical frameworks on adoption 12 2.3. The critique and research context 16 2.4. The AFI adoption analytical framework 17 2.5. Description of links between objectives and research questions 19 3. RESEARCH METHODOLOGY 21 3.1. Description of the study area 21 3.2. Selection of innovations and farmers 22 3.3. Research methods 23 3.3.1. Data collection methods 23 3.3.2. Sampling technique and sample size 24 3.3.3. Data analysis 25 4. RESULTS 26 4.1. Agroforestry adoption as a systems concept: a review 27 4.2. Can a sequential analysis provide a more robust understanding of farmers’ adoption decisions? an example from an agroforestry adoption study in Ethiopia 58 4.3. Farmers’ intentions towards sustained agroforestry adoption: an application of the theory of planned behavior 88 4.4. Adoption under the influence of innovation attributes: the case of agroforestry innovations from Ethiopia 111 4.5. Influence of system level factors on adoption of agroforestry innovations 141 5. SYNTHESIS and CONCLUSION 170 5.1. Synthesis of key findings 170 5.1.1. State of AFI adoption research in SSA 170 5.1.2. Persistent calls for rigorous research 172 5.1.3. Critical factors affecting AFI adoption 173 5.1.4. Conceptualizing adoption as a complex decision process 175 5.2. Reflections on research method, theoretical framework, and generalization 177 5.2.1. Reflection on research methods and analytical generalization 177 5.2.2. Reflection on the theoretical framework and theoretical contribution 179 5.3. Outlook and suggestions 184 5.4.1. Recommendations for future research 185 5.4.2. Development and policy recommendations 186 5.5. Limitations of the study 186 REFERENCES 187 APPENDICES 192

The population in the high mountains of the northwest provinces of Vietnam belongs to the poorest population in the country. Among the reasons behind this are the high frequency of minority groups in the region and the infertile soils of the steep slopes. As a result of the diversified elevation in northwest Vietnam, farmers are forced to cultivate fields with a gradient of more than 25 %. Additionally, the heavy rainfall events in the region increase the runoff, which is the main mechanism in erosion. Erosion leads to loss of bulk soil, and large losses of plant nutrients. In addition to erosion, nutrient leakage also occurs especially where a surplus of nutrients is applied. This is often the case when fertilizers are not applied with care. Nutrients are a limiting factor within agriculture, and with better nutrient management, the yield, and thus the farmers' economy, increases.The overall aim of this study was to locate and quantify sources and sinks of nutrients within the ten chosen farms. To achieve this aim, two specific objectives were researched. The first objective was to quantify the farm gate balance to get an overall idea of nutrient surplus and deficit and environmental risks. The second objective was to quantify and map out the internal flows i.e the field balances and the nutrients lost during manure storage. This will help locate sources and sinks of nutrients within each farm. Additionally, it will show if the grass strips help absorb nutrients lost through erosion.The study was carried out in Mai Son District in Son La Province in northwest Vietnam. The data was mainly collected through interviews with farmers on ten farms in the study area, as well as observations made during the field visit. Five farms with cows were chosen, while five farms had no cows. The farms mainly grew maize, longan, mango, and forage grass. Additionally, analyses were made on the nitrogen, phosphorous and potassium concentration in the compost, and the nitrogen concentration of the Guinea grass (Panicum maximum Jacq) which made up the grass-strips in the sloping land. The analysis of Guinea leaves was made to calibrate the SPAD-meter used in the field to gather nitrogen-values of the grass strips in the fields.The calculated balances indicated that the elements N, P and K on each farm varied between 32 to 580 kg/ha/year for N, -680 (16) to 53 kg/ha/year for P and -130 to 220 kg/ha/year for K. It also showed that Guinea grass, when grown along the contour lines, did as anticipated; absorb excess nutrients from the soil. However, the result shows that the forage grass mines the soil from potassium. Finally, the result showed that the farmers seem to over fertilize the plants. When estimating the nutrient lost from manure storage, the calculation showed significant losses of both nitrogen, phosphorus, and potassium during storage.The result of the study shows that the handling of manure, choice of compost or mineral fertilizer and fodder and use of grass strips on the farms affects the nutrient loss within the farm. It also shows that a system with forage grass on the contour is, above all, effective when used on farms with grass eating animals as the farmers otherwise don’t harvest the grass.