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L'agroforesterie, association d'arbres à des cultures ou de l'élevage, se pose désormais en alternative à l'agriculture industrielle. Ses principaux atouts sont la protection du sol, de l'eau et de la biodiversité, tout en maintenant une production agricole, et son rôle pour atténuer le changement climatique ou s'y adapter, sans oublier les multiples productions des arbres (bois, fruits, fourrage, médicaments, etc.). Retours d'expérience et données scientifiques sont maintenant disponibles mais il n'existait pas à ce jour d'ouvrage synthétique en français sur ce sujet. Mettre cette information à la disposition d'un large public afin d'encourager cette pratique innovante et mal connue : tel est le but de ce livre, afin de susciter de nouvelles initiatives et d'aider au changement. D'une lecture facile et incluant beaucoup d'exemples, accompagné d'une riche iconographie, d'un index détaillé et de nombreuses références scientifiques, Le Livre de l'agroforesterie permettra à tous, agriculteurs, techniciens, étudiants, chercheurs ou tout simplement curieux, de découvrir cette pratique et d'approfondir leurs connaissances.

National audience

New programs promoting agroforestry have emerged since the 2000s claiming a contribution to farmers' resilience. The objective of this study is to analyse the evolution of the value chain governance and its implications in terms of farmers' vulnerability reduction. The results are based on a detailed analysis of some thirty programs implemented by the firms holding the majority of market shares in cocoa and coffee sectors, a dozen of semi-structured interviews conducted with these firms, and farm level field surveys in Peru and Nicaragua. Our results show that cocoa and coffee sectors are facing new challenges on both the demand and supply sides : (1) there is an increasing demand for better quality products ; (2) the security of supply is threatened. This changing context is redefining the governance of cocoa and coffee value chains : industries downstream are developing partnerships with actors upstream to increase their control over their supply leading to an increased vertical coordination. Firm's position on the market determines the choice of coordination and agroforestry model to implement. The more the firms are positioned in niche markets, the more the link with the producer is essential and the more agroforestry is a central element of the partnership developed. Two key results emerged : (1) traders are becoming a key factor for the success of sustainable partnerships and (2) contract farming is creating an opportunity for more created shared value at farmers' scale.

Insetting is a way for chocolate makers to compensate their carbon emissions by financing the plantation of trees in supplying cocoa farms. It appears as a new way to finance agroforestry but also to create a link with producers and secure cocoa supply. However, whether insetting contributes to reduce smallholders' vulnerability and increase their fidelity is an empirical question that has to be addressed. A survey has been conducted in Peru (100 producers, 3 focus groups) to assess the benefits of the insetting programs and the challenges that remain. Results show that the partnership developed through the insetting program contributes to alleviate some difficulties preventing farmers to adopt agroforestry practices. However the implementation can be tricky and complex. Since insetting programs are based on a tripartite model dissociating the wood and the cocoa component, the planting of trees alone does not increase farmers' loyalty. In addition, an inadequate implementation might not impact farmers' vulnerability and could therefore lead to a negative vision of agroforestry. Insetting can be a viable financing solution for agroforestry dissemination but cannot be dissociated from an holistic approach of the farm focusing on a joint management of the crops. Alleviating poverty in rural cocoa communities requires also to break out of the carbon paradigm and to turn towards bottom-up approaches favouring social considerations and midterm visions.

Modern agroforestry emerged in the 70's as an answer to the disappearance of tropical rainforests. To improve land management, it was felt necessary to combine crops, trees and animals and apply management practices compatible with the cultural patterns of the local population. Yet, today's agroforestry relies often on simplified associations of one crop and one tree species. Such associations ignore the “forest dimension” of agroforestry and fail to restore forest-like ecosystems and promote local cultural values. I argue that between the 2 extremes of “forest gardening” and a simplified two-plant association, there is a continuum of multilayer agroforestry options with environmental attributes close to natural ecosystems, management features compatible with existing practices and productive qualities comparable if not better than simplified associations. I provide examples from Indonesia (multistrata agroforests in Sumatra), Egypt (multilayer agriculture in the Nile Delta), Cameroon (cocoa agroforests near Yaoundé) and Bangladesh (agroforestry gardens near Rajsahi). They show that multilayer agroforestry has a range of sustainability attributes and performs well for soil carbon sequestration and climate change mitigation. If agroforestry is to play its role to address environmental and climate change challenges and diversify land-based commodities, it needs to learn from complex agroforestry associations and recommend them as viable alternatives to industrial agriculture.

This book has been published by Allenvi (French National Alliance for Environmental Research) to coincide with the 22nd Conference of Parties to the United Nations Framework Convention on Climate Change (COP22) in Marrakesh. It is the outcome of work by academic researchers on both sides of the Mediterranean and provides a remarkable scientific review of the mechanisms of climate change and its impacts on the environment, the economy, health and Mediterranean societies. It will also be valuable in developing responses that draw on “scientific evidence” to address the issues of adaptation, resource conservation, solutions and risk prevention. Reflecting the full complexity of the Mediterranean environment, the book is a major scientific contribution to the climate issue, where various scientific considerations converge to break down the boundaries between disciplines.

« Transformer les vies tout en préservant la planète », telle est l'ambition des 17 Objectifs de développement durable (ODD), cadre d'action à l'échelle planétaire adopté par tous les pays membres de l'ONU en septembre 2015. Universels, les ODD s'adressent autant aux pays du Nord qu'aux pays du Sud et concernent à la fois l'économie, le développement des sociétés et la protection de l'environnement. Lutte contre la pauvreté, égalité entre les sexes, accès de tous à une énergie propre et à une éducation de qualité, bonne santé et bien-être, villes durables, consommation et production responsables… c'est à un profond changement de modèle que nous invitent les ODD. Cette transformation passe par un dialogue renouvelé entre science, société et politique, et entraîne des mutations majeures dans les rapports Nord-Sud. Proposant une analyse critique de chacun des 17 Objectifs, de leurs interactions et des contradictions dont ils sont aussi porteurs, cet ouvrage réunit une soixantaine d'auteurs d'horizons divers : responsables d'institutions scientifiques, chercheurs, experts, acteurs du développement… Cette approche plurielle offre différentes clés de lecture et met en avant l'importance de la recherche pour comprendre les enjeux des ODD, mesurer l'avancement de leur mise en œuvre et concevoir, en lien avec la société, des solutions innovantes. Accessible à un large public, il apporte un éclairage inédit, à la fois critique et documenté, sur les grands défis de l'Agenda 2030 pour le développement durable.

Over the centuries, farmers from the countries bordering the Mediterranean have developed a variety of agricultural practices, providing a wide array of commodities that have made the Mediterranean diet world famous. However, climate change projections reveal that some of these practices are at risk because of the expected drier and hotter conditions coupled with soil and water constraints, as well as a higher fire frequency threat. Nevertheless, adapting to climate hazards has long been part of farming practice in this area. The growing of pulses or other drought-tolerant crops (olives, grapes, almonds, etc.), transhumance and the use of rangelands or tree fodder by livestock, as well as water harvesting techniques, are among some of the age-old solutions to erratic rainfall or hot summers. In this chapter, we highlight some of the challenges facing agriculture in the Mediterranean and provide a series of examples of how agricultural and livestock management can be better adapted to climate change. Reliable metrics are necessary to enable the impact of climate change to be assessed and targeted agricultural policies to be designed. Long-term environmental observatories are essential to improve land management in the context of global change. Modelling the projected effects of current climatic trends shows that regional agricultural import dependence will increase as the impacts of climate change become more severe. Small ruminants (sheep, goats) have a good adaptation potential and can play a food security net role under climate change with a view to responding to the local food demand that emerges with new life styles. Local small ruminant breeds are adapted to harsh environments but this unique genetic heritage is now endangered. Perennial forage grasses are an alternative to cereals due to lower input requirement, year-round soil cover and optimal use of water. Mediterranean fruit trees, although well adapted, face increases in temperature and soil salinity as well as decreases in water availability. They will require improvements such as selection of early flowering varieties (olive), assessment of best pollinating conditions (figs) and salt tolerant rootstock (citrus). Depuis des siècles, les agriculteurs de la zone méditerranéenne ont mis au point une large gamme de pratiques agricoles à l’origine de productions qui ont rendu le régime alimentaire méditerranéen célèbre dans le monde entier. Les projections climatiques montrent cependant que des risques de sécheresse et de température élevée, associés à des contraintes concernant le sol, l’eau et les dangers d’incendie, menacent certaines de ces pratiques. L’adaptation à l’aléa climatique est néanmoins une habitude ancienne dans cette zone. La culture de légumes secs ou d’autres cultures tolérantes à la sécheresse (olives, raisin, amandes, etc.), la transhumance, l’utilisation des terrains de parcours et du fourrage arboré par le bétail, ou encore les techniques de capture de l’eau, font partie de ces solutions ancestrales au problème de la pluviométrie irrégulière ou des étés caniculaires. Dans ce chapitre, nous présentons certains des défis auxquels l’agriculture méditerranéenne est confrontée et nous proposons quelques exemples illustrant l’adaptation de l’agriculture et de l’élevage au changement climatique. Pour évaluer l’impact du changement climatique et concevoir des politiques agricoles appropriées, des mesures fiables sont nécessaires. Pour améliorer la gestion des terres dans un contexte de changement climatique, des observatoires environnementaux à long terme sont indispensables. La modélisation des effets attendus du changement climatique montre que la région deviendra progressivement plus dépendante des importations agricoles. Les petits ruminants (moutons, chèvres) ont un fort potentiel d’adaptation et peuvent jouer un rôle de filet de sécurité alimentaire en accord avec les nouvelles exigences alimentaires liées à de nouveaux styles de vie. Les races locales de petits ruminants sont adaptées à des environnements contraignants mais ce patrimoine génétique est désormais menacé. Les graminées fourragères pérennes représentent une alternative aux céréales en raison de leurs exigences modestes en intrants, de leur capacité à couvrir le sol toute l’année et de leur utilisation optimale de l’eau. Bien qu’ils soient bien adaptés, les arbres fruitiers méditerranéens sont confrontés à l’augmentation de la température et de la salinité du sol ainsi qu’à une diminution des réserves en eau. Ils devront faire l’objet d’améliorations comme la sélection de variétés à floraison précoce (oliviers), la prise en compte des conditions de pollinisation (figuiers) ou le greffage sur des porte-greffes tolérants à la salinité (agrumes).

Après avoir été systématiquement arrachés pour aménager de grandes surfaces aisément cultivables, les arbres font leur réapparition en agriculture. Ils assument des rôles multiples : fixateur d'humidité, ombrage, brise-vent, anti-érosion.

The 4‰ Initiative launched by the French government at COP21 in Paris in December 2015 aspires to increase global soil organic carbon (SOC) stocks at a rate of 0.4% per year. We conducted a systematic literature review on SOC storage under agroforestry and conservation agriculture systems in sub-Saharan Africa, where we reported 66 and 33 cases for both systems, respectively. The results showed that SOC storage rates were significantly higher than 4‰ yr-1 in fallows and in multistrata agroforestry systems (p-value = 0.0001 and 0.0178, respectively), but not in alley cropping and parklands systems. For conservation agriculture, only SOC storage rates in the system with all three principles applied, i.e. no- or minimum tillage combined with crop residue retention and intercropping or rotation, were significantly higher than 4‰ yr-1 (p-value = 0.0438). The data showed very large variability in SOC storage rates as the result of various factors, including previous land-use history, experimental set up and approach used to determine SOC storage, depth of soil sampling, soil type, type of cropping/agroforestry system and management, and duration of the experiment. SOC storage rates significantly decreased with time in the agroforestry systems (p-value = 0.0328). Our review clearly highlighted the scarcity of good quality data on SOC stocks in sub-Saharan Africa. We argue that there is a potential for SOC storage in agricultural soils of sub-Saharan Africa given the large areas of SOC-depleted soils, as illustrated by soil fertility gradients observed on smallholder farms. Low SOC levels are to a great extent the result of limited resources of most smallholder farmers in sub-Saharan Africa. The 4‰ initiative has to be implemented on the grounds of the positive impact on crop productivity rather than on climate change mitigation. The efficiency in doing so will depend on the specific situations and will need economic support to smallholder farmers.