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Lignocellulosic biomasses have some characteristics that hinder their use as fuel. Further, the biodegradation processes that can occur during storage can affect their energy properties. Torrefaction can improve their energy properties while reducing the impacts of storage. Near-infrared (NIR) spectroscopy could be a promising tool to estimate changes to biomass properties during storage. A series of waste feedstocks, including: sugarcane bagasse, coffee husk, eucalyptus, and pine were torrefied at 290 °C in a screw reactor, over 5, 7.5, 10, 15, or 20 min. Then, raw and torrefied biomasses were submitted to leaching and to white and brown-rot fungi, to simulate storage conditions. The weight loss (WL) due to fungal degradation after 2, 4, 8, and 12 weeks was measured and the high heating value (HHV) of all biodegradation steps, including raw and torrefied samples after leaching, were determined. All the samples were analysed by NIR spectroscopy and chemometric models were then developed. Firstly, partial least squares for discriminant analysis (PLS-DA) models successfully classified the four different residual biomasses into raw and torrefied forms according to fungal decomposition. Secondly, partial least squares regression (PLSR) models showed potential utility in an industrial context as a standardized continuous method to predict the HHV during biomass storage steps. While, PLSR models did not present good accuracy when estimating WL resulting from fungal degradation, they can be useful for screening during decision making. Further studies are required to improve and develop more efficient models to predict the fungal degradation level of stored biomasses. For exemple, in considering the class of torrefied biomasses, the model could show better predictive capacity due to less variability in the data. These results highlight the potential of NIR spectroscopy as a simple, fast, and efficient tool to analyze the degradation process over time. Such a rapid and non-destructive characterization tool could be very useful in industry to assess biomass property changes during storage.

Sugarcane Bagasse (SCB) has some characteristics that hinder its direct use as fuel. Torrefaction pre-treatment could be considered to improve the SCB properties for an energy use and to reduce the impact of storage on the reduction of these energy properties. SCB were torrefied at 290 °C in a screw reactor, during 5, 7.5 and 10 min. Then, raw and torrefied SCB samples were exposed successively to water-leaching and to white and brown rot fungi, to emulate storage conditions. Mass loss after water-leaching process, moisture content and weight loss due to fungal deterioration after 2, 4, 8, 12, 16 weeks were recorded on each SCB samples. Finally, chemical composition and High Heating Value of the torrefied samples were measured to determine the alterations compared to raw SCB during their storage mimic. Increasing torrefaction duration improves the SCB decay resistance. According to the fungal exposure duration, loss of carbon was recorded, however, HHV remain higher for torrefied SCB than those of raw SCB. Carbon contents and HHV values of raw and torrefied SCB during Trametes versicolor exposure [55.20% > C > 44.55% and 21.260 MJ kg−1 > HHV >17.307 MJ kg−1, results from all tests combined.], and during exposure to Coniophora puteana [55.20% > C > 46.25% and 21.260 MJ kg−1 > HHV > 17.699 MJ kg−1] tend to decrease. Severe torrefaction is therefore a good way to improve SCB energy properties while limiting loss of their energy properties during storage.

Previous studies have quantified the efficiency of biomass torrefaction processes by proposing severity indexes to discuss the variability of thermally modified biomass properties. However, comparisons of the accuracy and applicability of those indexes are few in the literature. To fill that gap, this study sought to assess five indexes usually applied in some torrefaction studies: weight loss, index of torrefaction, torrefaction severity index, severity factor, and torrefaction severity factor. These indexes were compared to characterize torrefaction under different conditions, and their accuracy in evaluating, correlating and predicting the physical, chemical and energetical properties of torrefied eucalyptus. As a result, the five evaluated indexes presented R2 > 0.84 and p -values ≤ 0.05 when evaluating basic properties. For all five indexes, there was a statistical significance when evaluating energy performance and R2 > 0.81. The three yield property-based indexes were more effective in predicting torrefied product properties and energy performance parameters. The two operating condition-based indexes were more effective in analyzing solid product properties than devolatilization. This work provided insight into which index is more appropriate for research and industrial applications.

International audience; In the world, oil provides 96% of transport needs, which mobilize 65% of the oil consumed and contribute 20% to CO2 emissions. One of the alternatives to reduce the consumption of fossil resources is the use of "biofuels". These biofuels are classified into three successive generations. The first generation biofuels come from the food parts of field crops: bioethanol and biodiesel. Second generation "advanced" biofuels come from lignocellulosic resources (wood, agricultural residues, etc.) valued either as bioethanol or synthetic hydrocarbons. A third generation is based on the culture of micro-algae producing fatty acids transformed into biodiesel. The first generation biodiesels, like those of the second and third generations, are subject to certain criticisms in particular the LUC (Land-Use Change) and the food versus energy competition. The objective of this work is to examine the interest of two promising ways. Biodiesel based on dedicated crops lead to reduced environmental impacts but play a role in the problem of LUC. While those based on residues are not part of the problem and show levels of reduction of greenhouse gas emissions between 83 and 90% against 60 to 80% for a conventional biodiesel compared to a fossil diesel fuel. Butyl esters of used edible oils and animal fats are displayed as "greener" biodiesels and represent an opportunity for second generation biofuels and for a greener oleochemistry.; Dans le monde, le pétrole assure 96% des besoins des transports, lesquels mobilisent 65% dupétrole consommé et participent à hauteur de 20% aux émissions de CO2. Afin de réduire la consommationde ressources fossiles, une des alternatives est notamment l’utilisation de « biocarburants ». Cesbiocarburants sont classés en trois générations successives. Les biocarburants de première génération sontissus des parties alimentaires de plantes de grande culture : le bioéthanol et le biodiesel. Les biocarburantsdits « avancés » de seconde génération sont issus de ressources lignocellulosiques (bois, résidus agricoles...)valorisées soit en bioéthanol soit en hydrocarbures de synthèse. Une troisième génération repose sur la culture de micro-algues productrices d’acides gras transformés en biodiesel. Les biodiesels de première génération, tout comme ceux de deuxième et troisième générations, sont sujets à certaines critiques notamment le CAS (changement d’affectation des sols) et la compétition alimentaire/énergétique. L’objectif de ce travail est d’examiner l’intérêt de deux filières prometteuses. Les biodiesels basés sur des cultures dédiées conduisent à des impacts environnementaux plus réduits mais jouent un rôle dans la problématique des CAS. Alors que celles basées sur les résidus n’y entrent pas et montrent des niveaux de réduction des émissions de gaz à effet de serre entre 83 et 90% contre 60 à 80% pour un biodiesel classique par rapport à un carburant diesel fossile. Les esters butyliques d’huiles alimentaires usagées et de graisses animales s’affichent comme des biodiesels « plus verts » et représentent une opportunité pour les biocarburants de deuxième génération et pour une oléochimie « plus verte ».

Performance of wood gasification genset is sensitive to the moisture content in the feedstock and the electrical load (demand of users). This study investigates the influence of these process parameters on the electrical efficiency of the genset (ηglobal), the electrical engine efficiency (ηengine), the cold gas efficiency (CGE), and the syngas composition. Experimental tests were carried out by varying the moisture content from 11% to 23% and the electrical power from 4.7 kW to 12.8 kW on a commercial gasifier equipped with precise measuring tools. The increase of the performance when the electrical load is increased or when the moisture content in the wood chips is decreased is both quantified and discussed. Such behaviour was mainly explained by differences in engine filling rates and reactor temperatures.

The use and cost of energy in agriculture have increased, making it necessary to make current agricultural practices more energy efficient. To do this, the prevailing systems must be thoroughly analysed. Studies have focused on assessing the energy performance of individual crops, but notably few studies have investigated different cropping systems. This paper aims to assess the energy performance of the two most used cropping systems of the Indo-Gangetic plains in India, namely Paddy rice–Wheat (PW) and Paddy rice–Potato (PP). The PW system was more energy efficient with Energy Use Efficiency (EUE) of 6.87 ± 1.7 compared to 3.61 ± 0.58 for the PP system. Higher Energy Efficiency Ratio (EERM) (3.94 ± 1.30) and Specific Energy(4.39 ± 2.06) (SE) were reported for the PW system, compared to 2.62 ± 0.47 and 2.15 ± 0.35 respectively for the PP system. Fertiliser use accounted for the highest input energy consumption in both systems, accounting for 58% and 51% of the energy consumed in PW and PP systems respectively, followed by fuel, seeds and electricity. The net income from the PP system (2295.7 ± 457.4 USD.ha−1.yr−1) was higher than that from the PW system (1555.4 ± 856.6 USD.ha−1.yr−1). The higher return of PP system was attributed to higher yield and better market price for the potato produce. There were no significant differences reported for various energy and economic parameters within different farm sizes in the PP system. However, for PW system, small farms were energy efficient while larger farms were economically efficient. Keywords: Energy input–output analysis, Indo-Gangetic plains, Energy use efficiency, Cropping system, Paddy rice, Wheat and potato

O artigo discute os desafios das políticas públicas em promover a governança dos recursos naturais na região do Submédio rio São Francisco, em particular as interações por vezes conflituosas entre segurança hídrica, alimentar, energética, e socioambiental. A evolução dos processos de ocupação do território e de implementação de políticas públicas será apresentada numa primeira seção, com foco nos projetos energéticos e suas interações com a utilização de recursos hídricos e com questões produtivas e agrárias. A segunda seção apresenta os dados primários de investimento público na região, cujo alvo tem sido os projetos eólicos, e as interações interinstitucionais para a execução destes recursos. A terceira seção discute os riscos apresentados pelos projetos eólicos, no sentido de reproduzir os padrões desiguais de investimentos no território e aumentar a vulnerabilidade socioambiental, apesar do potencial destes projetos em promover a mitigação das mudanças climáticas.

Hydropower production is altering the Mekong River basin’s riverine ecosystems, which contain the world’s largest inland fishery and provide food security and livelihoods to millions of people. The basin’s hydropower reservoir storage, which may rise from ∼2% of its mean annual flow in 2008 to ∼20% in 2025, is attenuating seasonal flow variability downstream of many dams with integral powerhouses and large storage reservoirs. In addition, tributary diversions for off-stream energy production are reducing downstream flows and augmenting them in recipient tributaries. To help manage tradeoffs between dam benefits (hydropower, irrigation, flood control, domestic water supply, and navigation) and their consequences for livelihoods and ecosystems, we review observed and projected impacts on river flows along both the Mekong mainstream and its tributaries. We include the effects of diversions and inter-basin transfers, which prior reviews of flow alteration in the Mekong basin have largely neglected. We also discuss the extent to which concurrent changes in climate, water demand, and land use, may offset or exacerbate hydropower-induced flow alteration. Our major recommendations for assessing hydrological impacts in the Mekong and other basins undergoing rapid hydropower development include synchronizing and integrating observational and modeling studies, improving the accuracy of reservoir water balances, evaluating multi-objective reservoir operating rules, examining hydropeaking-induced flow alteration, conducting multi-dam safety assessments, evaluating flow indicators relevant to local ecosystems and livelihoods, and considering alternative energy sources and reservoir sedimentation in long-term projections. Finally, we strongly recommend that dam impact studies consider hydrological alteration in conjunction with fish passage barriers, geomorphic changes and other contemporaneous stressors.

International audience; Production of energy from lignocellulosic biomass using internal combustion engines (ICE) is desirable, provided that costs can be reduced. The recalcitrance of lignocellulosic biomass requires additional treatments for second-generation biofuel conversion processes, falling short of sustainability goals and profit margins. Rather than transforming solid biomass to liquid or gaseous fuels through multistep processes, this paper explores the direct use of biomass powder below 200 μm in an engine. Reducing biofuel production to a single milling process offers the chance to downscale biofuel production for implementation at the local level, through standalone or hybrid installations with other renewable energies. In scenarios using intermittent energies such as solar or wind, production of biomass powder can be operated during low demand periods to store surplus energy which can be later used for generating power on demand. To test the feasibility of this concept, four biomasses (rice husk, chestnut wood, pine bark, and wheat straw) were micronised to an average particle size of 20 μm and fuelled in an instrumented ICE. Our results confirm that an ICE can start and run with various biomass types at a wide range of operating regimes without any assistance. During these tests, efficiencies up to 17.5% were observed with powdered rice husk, using an intake temperature of 40 °C. Emissions (CO, NOx, and SO2) were found to be within acceptable operating limits of available aftertreatment technologies. This first assessment of the compared combustion behaviour of different biomass powders in ICE highlights the fact that the challenges associated with this alternative biofuel demand a cross-disciplinary approach from research domains such as dust explosion prevention, biomass combustion and engine technology.

Low carbon strategies recently focus on soil organic carbon (SOC) sequestration potentials from agriculture and forestry, while Life Cycle Assessment (LCA) increasingly becomes the framework of choice to estimate the environmental impacts of these activities. Classic LCA is limited to static carbon neutral approaches, disregarding dynamic SOC flows and their time-dependent GHG contributions. To overcome such limitation, the purpose of this study is to model SOC flows associated with agricultural land use (LU) and the provision of agricultural substrates to transport biofuels, thus generating dynamic inventories and comparatively assessing energy policy scenarios and their climate consequences in the context of dynamic LCA. The proposed framework allows computing SOC from annual and perennial species under specific management practices (e.g. residue removal rates, organic fertiliser use). The results associated with the implementation of three energy policies and two accounting philosophies (C-neutral and C-complete) show that shifting energy pathways towards advanced biofuels reduces overall resource consumption, LU and GHG emissions. The French 2015 Energy Transition for Green Growth Act (LTECV) leads towards higher mitigation targets compared with business-as-usual (BAU) and intermediate (15BIO) policy constraints. C-neutral results show reduced radiative forcing effects by 10% and 34% for 15BIO and LTECV respectively, with respect to BAU. C-complete (i.e. dynamic assessment of all biogenic- and fossil-sourced C flows) results reveal further mitigation potentials across policies, whereof 50%-65% can be attributed to temporal C sequestration in perennial rhizomes. A sensitivity analysis suggests important SOC variations due to temperature increase (+2°C) and changes in residue removal rates. Both parameters affect mitigation and the latter also LU, by a factor of −0.56 to + 5. This article highlights the importance of SOC modelling in the context of LU in LCA, which is usually disregarded, as SOC is considered only in the context of land use change (LUC).

Unravelling the dynamics of land-use change is key to assess the environmental and socioeconomic impacts of land-based strategies regarding climate or energy. In this prospect, this paper proposes an analytical decomposition of land-use change resulting from a shock in agricultural demand which takes into account indirect effects from price signals. This analytical equation is numerically estimated using a global model of land-use combining biophysics and economics. While being relatively simple, this model captures the main processes of land-use change: change in the intensive and extensive margins, international trade, change in intermediary demand and possible by-products. At the global scale, our results show that yield losses due to the conversion of marginal land amount approximately to half of yield gains due to fertiliser use. At the regional scale, patterns of yield and area responses are depicted by assessing the potentials for intensification (yield gaps) and extensification (areas of extensive pastures) given the future pathways of agricultural demand.

We analyse the threats of global environmental change, as they relate to food security. First, we review three discourses: (i) 'sustainable intensification', or the increase of food supplies without compromising food producing inputs, such as soils and water; (ii) the 'nexus' that seeks to understand links across food, energy, environment and water systems; and (iii) 'resilience thinking' that focuses on how to ensure the critical capacities of food, energy and water systems are maintained in the presence of uncertainties and threats. Second, we build on these discourses to present the causal, risks and options assessment for decision-making process to improve decision-making in the presence of risks. The process provides a structured, but flexible, approach that moves from problem diagnosis to better risk-based decision-making and outcomes by responding to causal risks within and across food, energy, environment and water systems.

Dans ce compte-rendu, je donnerai d'abord les grands traits de la présentation faite à la conférence (Paradigm shift in Agriculture : agro-ecological transition & ecological intensification, two case studies in Reunion Island and Senegal). Je dresserai ensuite une 'big picture' de la transition énergétique telle qu'elle ressort des contributions à la conférence, et conclurai enfin sur une mise en perspective de la transition énergétique et de la transition agro-écologique.

Esta obra tiene la ambición de problematizar la situación de la investigación realizada en el marco de las agriculturas familiares Esta obra tiene la ambición de establecer un estado de situación analítico sobre la investigación realizada en el marco de las agriculturas familiares. Se interroga sobre los métodos y los resultados de la investigación para el desarrollo en lo referente a las agriculturas familiares, así como su lugar y su papel frente a los desafíos del planeta. No se trata entonces de una defensa — algunos actores del desarrollo lo hacen por sí mismos y no necesitan al apoyo del mundo de la investigación — sino de un esfuerzo por señalar la problemática de la diversidad y de las especifcidades de esta forma de producción, bajo el enfoque de los retos del desarrollo agrícola y rural. A través de este análisis, el libro interroga de manera más general, tanto en el plano nacional como internacional, las decisiones tomadas desde el punto mde vista de sociedad y de trayectoria de desarrollo, así como el papel que en ello juega y deberá jugar la agricultura.

Au Maroc, le gaz butane est fortement subventionné pour son usage domestique, et est devenu depuis une dizaine d'années une des sources principales d'énergie utilisées pour le pompage de l'eau souterraine dans les exploitations agricoles. Du fait de son coût élevé pour les finances publiques, il est envisagé un arrêt de cette subvention, couplé à une éventuelle subvention à l'investissement en énergie solaire. La présente étude analyse l'impact de scénarios d'évolutions des politiques énergétiques nationales sur des exploitations irrigantes. Ces évolutions possibles de type d'énergie utilisé sont analysées à la fois en termes de rentabilité et selon le point de vue de l'exploitant lui-même. Un ensemble de 18 exploitations, utilisant 4 différents types d'énergie (gasoil, butane, électrique, photovoltaïque), ont été enquêtées dans la plaine du Saiss. Trois scénarios ont été établis : 1) un arrêt de la subvention au butane ; 2) un arrêt de la subvention couplé à une subvention à l'investissement dans l'énergie solaire ; et 3) un arrêt de la subvention butane couplé à une subvention à l'investissement dans l'énergie électrique. Les résultats montrent que, en cas d'arrêt de la subvention sur le butane, la moitié des exploitants utilisant le butane lors de l'étude envisagent de revenir au gasoil. En cas de subvention de 50% des coûts d'installation de l'énergie photovoltaïque, trois quarts des agriculteurs utilisant le butane ou le gasoil changeraient de système. Seule la moitié des exploitations en butane ou gasoil serait intéressée par un passage à l'électrique, même dans le cas d'une forte subvention à l'investissement. La transition vers le photovoltaïque, préférée par les agriculteurs utilisant le butane ou le gasoil, ne sera pas cependant qu'une question de taux de subvention, du fait notamment d'un fort besoin d'appui technique pour la conception d'un tel système au niveau des exploitations. Par ailleurs, elle devra être liée à la mise en oeuvre de mécanismes de régulation spécifiques de façon à ne pas contribuer à une augmentation de l'utilisation des ressources en eau souterraines.

La diversification du mix energetique vers les energies renouvelables est un objectif politique majeur au Burkina Faso. Pourtant, cet objectif donne lieu a des politiques, des strategies ou des programmes sectoriels elabores sans grandes concertation et coherence, avec un faible souci de leur mise en œuvre et isoles dans le jeu d’ensemble de l’action publique dans le domaine energetique.Classification JEL : H11, O11, Q28, Q48

In Morocco, irrigation has been a major component of the development policy pursued by the State in the last half century, to prevent climatic risks and to ensure minimum food security. Investments in irrigation led to the rapid growth of agriculture and improved the sector's contribution to the national economy. The recent strategy in the agricultural sector (PMV) reinforced this trend, particularly by providing substantial subsidies for the conversion of existing irrigation systems (sprinkler and gravity) to localized irrigation systems, which are assumed to be “water saving techniques”. These increased efforts led to intensification and resulted in an increase in energy consumption in the sector. The objective of this study was to assess the consumption and the multiplier effect of the use of energy and irrigation water for agriculture at a regional level in Morocco. Using a social accounting matrix (SAM), we identified the direct and indirect economic effects of subsidizing energy used by agriculture. The results show that the water saving policy in Morocco, targeting "water-saving" techniques, leads to an increased use of subsidized butane. Results also showed that indirect effects, through energy subsidies, exceed the direct effects of agricultural subsidies. (Texte intégral)

This study aims to evaluate the performance of groundwater-based tube well irrigation systems of Sarlahi District in Nepal considering a water–energy–food nexus approach. The deep tube well (DTW) irrigation systems showed better performance over shallow tube well (STW) irrigation systems in terms of water supply and agricultural output per unit of irrigated area. On the other hand, the STW-based irrigation systems showed better performance in terms of energy use, management operation and maintenance (MOM) cost and benefit–cost ratio compared to DTW-irrigated systems. The productivity of irrigation water and energy input to major crops showed the best performance for maize followed by rice and wheat. The simulated yields of cereal crops through the AquaCrop model showed significant scope for enhancing crop yields and associated benefits through judicious use of water and fertilizer.

Intertwined with agricultural issues and closely linked to the challenges of poverty discussed in Chap. 10, the production of and access to energy are major issues for the growth of the South and for the attainment of the Millennium Development Goals. They are among the foremost prerequisites for economic and human development (Sachs 2005). In the agricultural and agrifood domain, energy remains a key factor for improving the production, harvesting, storage, processing and marketing of agricultural products (FAO 2000). Access to energy in rural areas is, in general, synonymous with improving the conditions of life and the diversification of income generating activities.

Energy availability, heat conversion and transfer still represent an impediment to the food processing sector in developing countries. Optimisation of tubular heat exchangers remains a concern for equipment designers and manufacturers. This work assesses the performances of a turbulator in terms of heat transfer and fluid friction characteristics in a heat exchanger tube. The turbulator is designed based on an elliptic shape suited to be made locally. The geometric dispersions caused by this kind of manufacturing process were surveyed, and then considered in the study. Hence 26 turbulators, manufactured with or without geometric dispersions, and with 45° or 60° ellipses, were tested in three tubes of different diameters. To ensure the closest possible resemblance to actual applications, the tests were carried out using air as a working fluid, with a low range of Reynolds number (1700–8000 for heat transfer and 3000 to 16,000 for friction factor). The heat transfer rate in a tube fitted with a turbulator may be increased up to 900%, in turbulent flow and with a curve angle of 45°. On the flip side, there is a very big pressure drop. However, a surface-based dispersion of 30% which could be generated by local manufacturing leads to a 50% reduction in the friction factor, but only a 20% reduction in the Nusselt number. The models obtained will enable a multi-criteria analysis for heat exchanger optimisation in a context specific to developing countries.

Pendant la saison sèche en régions semi-arides, les animaux sont maintenus sur des fourrages de pauvre qualité, nécessitant certaines formes de complémentation protéique pour améliorer leur productivité. Dans cette étude, le Calopogonium mucunoides a été distribué à des ânes de trait pendant la saison sèche pour tester son appétibilité et ses valeurs nutritionnelles. Douze ânes adultes ont été répartis en trois groupes alimentés de la manière suivante: groupe A a reçu des tiges de maïs et 0,5 kg d'une provende domestique constituée d'un mélange de son de maïs et de tourteau de coton, groupe B a reçu du C. mucunoides et 0,25 kg de provende, et groupe C a reçu du C. mucunoides et 0,5 kg de provende. La consommation de fourrage, d'eau et le poids vif des animaux ont été enregistrés. Les résultats n'ont montré aucune différence significative dans la consommation des fourrages. Une différence très significative (P < 0,001) a été observée en matière de digestibilité avec la plus importante digestibilité dans les groupes alimentés avec du C. mucunoides. En dépit de sa faible appétibilité ou acceptabilité par d'autres espèces d'animaux d'élevage, le C. mucunoides, comme légumineuse fourragère, présente un taux élevé de matières azotées brutes et pourrait efficacement remplacer des compléments protéiques agro-industriels que les paysans ont de plus en plus de difficultés à se procurer.

Que sont les agricultures familiales ? Quels peuvent être leurs rôles face aux défis de la planète et leurs contributions à un développement durable et plus équitable ? Mode d'organisation dominant de l'agriculture, en particulier dans les pays du Sud, l'agriculture familiale est aussi une agriculture de demain. Les Nations unies, en décrétant 2014 " Année internationale de l'agriculture familiale ", placent cette forme de production au centre des débats sur le développement agricole. Ceux-ci sont souvent réduits à une opposition entre l'essor d'une agriculture de firme, soi-disant performante parce que relevant de processus industriels de production de masse destinée aux marchés, et le maintien d'une agriculture familiale fondée sur la proximité entre famille et exploitation. Les auteurs de cet ouvrage souhaitent enrichir ces débats pour dépasser les stéréotypes, souvent exprimés en termes de " agricultures de petite taille, de subsistance, paysanne... ". Les résultats de la recherche démontrent la formidable adaptabilité des agricultures familiales et leur capacité à répondre aux grands enjeux de demain, mais n'occultent pas pour autant leurs limites. Aux niveaux national et international, les auteurs interrogent les choix de société et de trajectoire de développement, ainsi que les rôles que l'agriculture devra y jouer. Ils plaident pour un réengagement des politiques publiques en faveur des agricultures familiales des pays du Sud et soulignent l'importance de prévoir des actions ciblées et adaptées aux spécificités du caractère familial des modèles agricoles. Mais ils insistent surtout sur le besoin de dépasser des logiques strictement sectorielles, en plaçant les agricultures familiales au coeur d'un projet économique et social plus large. Cet ouvrage, issu d'un travail collaboratif conduit par le Cirad, consacre trois décennies de recherches sur ce sujet. Il intéressera les chercheurs, enseignants et étudiants, et les acteurs des instances nationales et internationales liées au développement des pays du Sud. Sommaire : Préface (Ibrahim Assane Mayaki). Introduction générale (Jean-Michel Sourisseau). Partie I - Définir et comprendre les agricultures familiales (Coordination : Pierre-Marie Bosc, Laurent Parrot, Christian Corniaux). 1. Les agricultures familiales : au coeur de l'histoire des agricultures du monde (Bruno Losch). 2. Définir, caractériser et mesurer les agricultures familiales (Pierre-Marie Bosc, Jacques Marzin, Jean-François Bélières, Jean-Michel Sourisseau, Philippe Bonnal, Bruno Losch, Philippe Pédelahore, Laurent Parrot). 3. Les familles, le travail et l'exploitation agricole (Véronique Ancey, Sandrine Fréguin-Gresh). 4. Agricultures familiales et autres formes d'agriculture (Jacques Marzin, Benoît Daviron, Sylvain Rafflegeau). Partie II - Contribuer à nourrir le monde et à faire vivre les territoires (Coordination : François Affholder, Laurène Feintrenie, Bruno Losch). 5. Contribuer aux systèmes écologiques et sociaux (Laurène Feintrenie, François Affholder). 6. Contribuer aux dynamiques territoriales (Stéphanie Barral, Marc Piraux, Jean-Michel Sourisseau, Élodie Valette). 7. Contribuer à la production et aux marchés internationaux (Sylvain Rafflegeau, Bruno Losch, Benoît Daviron, Philippe Bastide, Pierre Charmetant, Thierry Lescot, Alexia Prades, Jérôme Sainte-Beuve). 8. Contribuer à l'innovation, aux politiques et à la démocratie locale (Pierre-Marie Bosc, Marc Piraux, Michel Dulcire). Partie III - Relever les défis du futur (Coordination : Philippe Bonnal, Ludovic Temple). 9. Défis de pauvreté, d'emploi et de sécurité alimentaire (Philippe Bonnal, Bruno Losch, Jacques Marzin, Laurent Parrot). 10. Les défis énergétiques : menaces ou opportunités ? (Marie-Hélène Dabat, Denis Gautier, Laurent Gazull, François Pinta). 11. Des défis sanitaires de plus en plus prégnants à l'échelle globale (Sophie Molia, Pascal Bonnet, Alain Ratnadass). 12. Défis de gestion et d'usage des ressources naturelles (Danièle Clavel

Hydropower and irrigation developments to address rising demand for food and energy are modifying the water balance of the Mekong Basin. Infrastructure investment decisions are also frequently made from a sub-catchment perspective. This paper compares river flows with irrigation development stages in the Nam Ngum sub-basin where the potential for irrigation and hydropower expansion is largely untapped. It shows that full hydropower development in this basin allows irrigation water use to triple, even as it reduces competition with environmental flow requirements. The implications for the wider Mekong are, however, unclear, particularly given uncertainty over parallel transformations elsewhere in the basin.