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International audience; Although Sierra Leone aims to improve the livelihoods of its rice-farming households, the effect of specific policy changes on diverse households remains an open question. This study presents a household model that simulates strategies of production and consumption for rice-farming households in Sierra Leone. It accounts for non-separability between household production and consumption decisions, accounts for resource constraints, and uses a risk-adjusted measure of welfare. The model simulated the effects of three policy scenarios seeking to improve food consumption and calculated production, consumption and socio-economic indicators. The scenarios included: 1) subsidizing rice seed costs, 2) subsidizing palm oil production costs, and 3) subsidizing the conversion of lowlands into land suitable for rice production. The model was applied to four representative rice-farming households in northern Sierra Leone that differed in their land resources and rice consumption. The four household types included: 1) Upland_intensive, 2) Lowland_intensive, 3) Upland_extensive, and 4) Lowland_extensive. Results show that extensive lowland-based households had the lowest rice consumption (54 kg capita−1 year-1) and caloric intake (843 Kcal capita−1 day−1) in comparison with the other household types. Subsidizing rice seed costs in the lowlands, compared to the baseline scenario, improved rice consumption across the households by 15–34%, and farm income by 12–57%. Regardless of the scenario, differences in caloric intake, in comparison to the baseline scenario, were less than differences in rice consumption, thus indicating substitution effects between the different foods (vegetables, cereals, oils, and sweet potatoes). A maximum caloric increase of 16% was achieved by subsidizing palm oil production costs. Subsidizing lowland conversion for rice cultivation improved rice consumption mainly through the subsidy’s positive effect on rice production, which in turn effected self-consumption. Depending on the scenario, the increase in household income was mainly because of an increase in upland rice area, an increase in rice sowing rates, an increase in cash, or a specialization in lowland rice combined with planting a cash crop.

International audience; This study considers a quantitative approach for assessing the performance of Tunisian farming systems to face climate change. It is based on the resilience concept and the calculation, with a modelling chain, of three indicators: land stock, labour stock, and income flux. Two system states, ‘‘base’’ and ‘‘climate change’’, and a time horizon of 2010–2025, are developed and compared for representative farming systems. The study shows that 55% of the farming systems were identified as being resilient to climate change. They are diversified and mostly grow cereals, vegetables, and forage crops combined with livestock, increasing their capability to mitigate climate change by reorganizing crop activities. 35% of the farms identified as being non-resilient are dominated by orchards, or cereals and orchards. They showed an important drop in farm income (-45%), mainly due to their inability to adapt their cropping systems to water stress and soil salinity. Finally, only 10% were identified as being poorly resilient farming systems. Those farms have mainly intensified cereal cropping systems based on a strategy of purchasing land to increase the surface area of profitable activities (forage and livestock). Overall, the methodology can be adapted for other dry land areas in the Mediterranean region and help experts and policy-makers to propose and test strategies for adapting to climate change.

Le present travail applique a la Tunisie, part d'un double constat relatif, d'une part, a la gravite de l'erosion et, d'autre part, a l'importance des depenses publiques en matiere de conservation des eaux et du sol visant a attenuer ce phenomene. La contradiction de ce double constat et la divergence des resultats obtenus par l'adoption de ces amenagements de conservation constituent le determinant principal pour la remise en cause de l'efficacite de cette intervention publique. L'evaluation quantitative de l'impact de ces amenagements sur le rendement, le systeme de production et par la sur la rentabilite des capitaux investis ainsi que sur l'erosion constituent, donc, l'objectif primordial de ce travail. L'approche bio-economique qui couple l'emploi d'un simulateur biophysique a un modele d'optimisation economique est avancee comme une meilleure methode pour juger cette efficacite.

Conference on Sustainable Diet and Food Security, 2013/05/28-29, Lille (France); International audience; The stark observation of the co-existence of undernourishment, nutrient deficiencies and overweight and obesity, the triple burden of malnutrition, is inviting us to reconsider health and nutrition as the primary goal and final endpoint of food systems. Agriculture and the food industry have made remarkable advances in the past decades. However, their development has not entirely fulfilled health and nutritional needs, and moreover, they have generated substantial collateral losses in agricultural biodiversity. Simultaneously, several regions are experiencing unprecedented weather events caused by climate change and habitat depletion, in turn putting at risk global food and nutrition security. This coincidence of food crises with increasing environmental degradation suggests an urgent need for novel analyses and new paradigms. The sustainable diets concept proposes a research and policy agenda that strives towards a sustainable use of human and natural resources for food and nutrition security, highlighting the preeminent role of consumers in defining sustainable options and the importance of biodiversity in nutrition. Food systems act as complex social–ecological systems, involving multiple interactions between human and natural components. Nutritional patterns and environment structure are interconnected in a mutual dynamic of changes. The systemic nature of these interactions calls for multidimensional approaches and integrated assessment and simulation tools to guide change. This paper proposes a review and conceptual modelling framework that articulate the synergies and tradeoffs between dietary diversity, widely recognised as key for healthy diets, and agricultural biodiversity and associated ecosystem functions, crucial resilience factors to climate and global changes.

Une« fonction de production d'ingenieur », qui fait appel a la fois a un simulateur de croissance de plantes et a de la programmation lineaire sous contrainte de risque, est utilisee pour analyser les consequences de la reforme « Me Sharry » sur les revenus et sur l'environnement, dans une grande variete de types d'exploitations de « grandes cultures » (dont certaines avec elevage), a travers toute la France. Le modele est dynamique et recursif au sens de Day. Malgre la grande diversite des situations, la reforme, dans l'ensemble, semble devoir atteindre les objectifs qui etaient les siens, avec une tendance a l'extensification et au reequilibrage entre les regions. Cependant, l'incertitude majeure, susceptible de remettre en cause ces resultats, reste la perception des risques encourus par les agriculteurs.

This report describes the generic template of a farm-household model for use in the context of developing countries in order to gain knowledge on food security and rural poverty alleviation under different economic conditions and agri-food policy options. This model, called FSSIM-Dev (Farming System Simulator for Developing Countries), is an extension of the FSSIM model developed within the SEAMLESS project. Contrary to most well-known household models which are econometric based, FSSIM-Dev is a non-linear optimization model which relies on both the general household's utility framework and the farm's production technical constraints, in a non-separable regime. It is referred to as a static Positive Mathematical Programming (PMP) which optimise at farm household level, with the opportunities to simulate the exchange of production factors among farm-households. FSSIM-Dev is designed to capture five key features of developing countries or/and rural areas: (i) non-separability of production and consumption decisions due to market imperfection; (ii) interaction among farm-households for market factors; (iii) heterogeneity of farm households with respect to their both consumption baskets (demand side) and resource endowments (supply side); (iv) inter-linkage between transaction costs and market participation decisions; and (v) the seasonality of farming activities and resource use. Model use is illustrated in this report with an analysis of the combined effects of rice support policy, namely fertiliser subsidy policy, and improved rice cropping managements (practices) on the livelihood of representative farm households in Sierra Leone. Results show that, first, the improvement of rice cropping managements is a key factor to boost significantly farm household income in the studied region. Second, the amount of N fertilizer required for, mainly, upland rice appears too high and costly and could not be applied by farm households without policy support (i.e. subsidies). Third, both the simulated rice policy and the improved crop managements would increase farm productivity and boost household income but they are not sufficient to fight poverty since most of the farm household types would continue to live below the extreme poverty line of 1 USD-equivalent per day.

Pour prevoir les changements dans les techniques de production engenderees par une modification de la structure de prix, la demarche micro-economique usuelle repose sur la construction de fonctions de production et leur estimation econometrique. Nous proposons une autre methode d analyse de ces changements, basee sur un modele economique couplea un simulateur agronomique de croissance des plantes, EPIC (Erosion Productivity Impact Calculator). Cet outil nous permet de simuler le comportement d‘optimisation du producteur dans son univers agronomique, et de deduire les consequences des choix techniques sur certain. Parametres d'environnement. Une application illustre les eff ets de la reforme de la Politique Agricole Commune (PAC) dans deux regions cerealieres, francaises : la region de Toulouse (Midi-Pyrenees) et la Beauce (Centre). Pour les deux premieres annees de la reforme, les previsions etablies sont proches des evolutions reelles. Dans les deux regions, la reforme aurait un impact sign-cattfsur le developpement des principales cultures etfavoriserait l’emploi de technique. moins intensives. In order to predict changes in production techniques generated by modifications in the price structure, the usual microeconomic approach is based on the construction of production, functions estimated by econometric methods. We propose a different way to analyze the effects of these policy change. based on an economic mode1 associated with an agronomic simulation model, EPIC (Erosion Productivity Impact Calculator). This tool allows us to simulate the optimizing behavior of the producer in his/her agronomical universe, predicting the consequences of technical choices on some environmental parameters such as nitrate pollution. We apply this methodology to predict the effects of the Common Agricultural Policy reform (CAP) in two grain-producing French regions : Toulouse agricultural plain (South West) and La Beauce (Centre). The mode1 predicts an evolution toward less intensive production techniques, and changes in the trop pattern. The real changes that took place in the first two years of the reform have been quite close to the mode1 predictions.

Groundwater in Spain, as in other arid and semiarid countries worldwide, has been widely used in the expansion of irrigated agriculture. In the Spanish Mancha Occidental aquifer, the excessive, and sometimes illegal, water abstraction for irrigation has promoted outstanding socioeconomic development in the area, but it has also resulted in exploitation of the aquifer and degradation of valuable wetlands. Water policies implemented in the region have not yet managed to restore the aquifer and face strong social opposition. This paper uses a multi-scale modeling approach to explore the environmental and socio-economic impacts of alternative water conservation measures at the farm and basin levels. It also analyzes their comparative cost-effectiveness to help policy makers identify the least costly policy option for achieving the goal of the Mancha Occidental aquifer's sustainability. To conduct this analysis, a Mathematical Programming Model has been developed to simulate: the closing-up and taxed-legalization of unlicensed wells, uniform volumetric and block-rate water prices, water quotas, and water markets. Aggregate results show that net social costs are not substantially different across policy option, so none of the considered policy options will be clearly more cost-effective than the others. However, there are significant differences between private and public costs (at the farm and sub-basin levels), which will be critical for determining the application in practice of these policies. Results show that controlling illegal water mining (through the legalization of unlicensed wells) is necessary, but is not sufficient to recover the aquifer. Rather, effective water management in this area will require the implementation of other water management policies as well. Among them, uniform volumetric and block-rate water pricing policies will entail the lowest net social cost, but will produce important income losses in the smallest and most water-intensive farms, which might put at risk the viability of these farms and the social acceptance of the policies. Further investigations on social costs, policy enforcement capacity and public participation in water management are highly recommended.

International audience; Soil erosion is one of the most important of today’s environmental externalities and a major threat to sustainability of agricultural system. It constitutes the most widespread forms of land degradation throughout the world. The aim of this paper is to estimate the amount of soil erosion generated by the current cropping systems in Tunisia and to assess the economic and ecological impacts of policy instruments designed to handle this problem. The analysed policy options are based on soil conservation practices and direct incentive farming anti-erosive measures. The selected measures are the reduction of tillage, the avoidance of bare fallow and the use of legume-based crop rotation. A bio-economic modelling framework coupling the biophysical model EPIC to a non-linear dynamic programming farm model was used for this impact analysis. It was performed in a set of representative farms belonging to a region in North-Eastern Tunisia (Zaghouan) strongly affected by this phenomenon. The main finding of this research is the non-convexity of the crop yield—soil erosion space. That is, the use of more intensive techniques to increase productivity (i.e. crop yield) may be accompanied by rough changes in soil erosion (damage) curves, manifested either by non-monotony or non-convexity. In term of policy options and because of giving up convexity assumptions, incentive anti-erosive measures appear more efficient than conventional environmental policies such as Pigouvian taxes or quota systems. The implementation of soil conservation practices would leads to a net decrease in soil erosion and an increase in farm income. However, with the current interest rate of 7% the possible rise in income is not enough to stimulate farmers to invest on these practices. A maximum rate of 4% would be necessary to make this policy option more effective.; L'érosion des sols est l'une des plus importantes externalités environnementales d’aujourd’hui et une grave menace pour la durabilité des systèmes agricoles. Elle constitue la forme la plus répandue de la dégradation des terres dans le monde entier. Le but de cet article est d'estimer le niveau d'érosion des sols générée par les systèmes de culture actuels en Tunisie et d'évaluer les impacts économiques et écologiques des instruments de politique conçus pour traiter ce problème. Les options politiques analysées sont basées sur les pratiques de conservation des sols et des mesures directes d’incitation antiérosives. Les mesures choisies sont la réduction du travail du sol, la suppression de la jachère nue et l'utilisation des rotations culturales à base de légumineuses. La modélisation bioéconomique couplant le modèle biophysique EPIC à un modèle de programmation non-linéaire de type multipériodique récursif a été utilisée pour cette analyse d'impact. Elle a été appliquée à un ensemble d’exploitations-types appartenant à une région du Nord-Est Tunisien (Zaghouan) fortement touchée par ce phénomène. La principale conclusion de cette recherche est la non-convexité de l'espace production-érosion des sols. Autrement dit, l'utilisation de techniques plus intensives pour accroître la productivité (rendement des cultures par exemple) peut être accompagnée par des changements bruts dans la courbe de l'érosion des sols (dommages), qui se manifestent soit par des non-monotonies ou des non-convexités. En termes d'options politiques et en raison de l'abandon de l’hypothèse de convexité, les mesures d'incitation antiérosives apparaissent plus efficaces que les instruments conventionnels tels que la taxe Pigouvienne ou les systèmes de quota. La mise en œuvre des pratiques de conservation des sols conduirait à une diminution nette de l'érosion des sols et une augmentation du revenu agricole. Toutefois, avec le taux d'intérêt actuel de 7% la hausse possible du revenu n'est pas suffisante pour inciter les agriculteurs à investir dans ces pratiques. Un taux maximal de 4% serait nécessaire pour rendre cette option plus efficace.

Chapitre 5; The aim of this chapter is to present a bio-economic modelling framework established to provide insight into the complex nature of agricultural systems and to assess the impacts of agricultural and environmental policies and technological innovations. This framework consists of a Farm System Simulator (FSSIM) using mathematical programming that can be linked to a cropping system model to estimate at field level the engineering production and environmental functions. FSSIM includes a module for agricultural management (FSSIM-AM) and a mathematical programming model (FSSIM-MP). FSSIM-AM aims to define current and alternative activities and to quantify their input output coefficients (both yields and environmental effects) using a cropping system model, such as APES (Agricultural Production and Externalities Simulator) and other sources (expert knowledge, surveys, etc.). FSSIM-MP seeks to describe the behaviour of the farmer given a set of biophysical, socio-economic and policy constraints and to predict its reactions under new technologies, policy and market changes. The communication between these different tools and models is based on explicit definitions of spatial scales and software for model integration. The bio-economic modelling framework was designed to be sufficiently generic and flexible in order to be applied for all relevant farming systems across the European Union, easily transferable between different geographic locations, and reusable for different applications.; L’objectif de ce chapitre est de présenter un cadre de modélisation bioéconomique pour offrir un aperçu de la nature complexe des systèmes agricoles et pour évaluer les impacts des politiques agricoles et environnementales et des innovations technologiques. Ce cadre consiste en un modèle économique de ferme (FSSIM) basé sur la programmation mathématique qui peut être relié à un modèle biophysique pour estimer, au niveau parcellaire, les fonctions de production et d’externalité. FSSIM comprend un module de gestion des données (FSSIM-AM) et un modèle de programmation mathématique (FSSIM-MP). FSSIM-AM a pour but de définir les activités actuelles et alternatives et de quantifier leurs coefficients inputs-outputs (à la fois les rendements et les effets sur l'environnement) en utilisant un modèle biophysique, comme APES (Agricultural Production and Externalities Simulator), ainsi que d'autres sources (expertise, enquêtes, etc.). FSSIM-MP cherche à décrire le comportement de l'agriculteur en tenant compte d’un ensemble de contraintes biophysiques, socio-économiques et politiques et de prévoir ses réactions face à des changements de politiques et du marché ainsi que de nouvelles technologies. La communication entre ces différents outils et modèles est basée sur une définition explicite des échelles spatiales et des logiciels d'intégration. Le cadre de modélisation bioéconomique a été conçu suffisamment générique et flexible pour être appliqué à tous les systèmes de production en Europe, facilement transférables entre les différentes implantations géographiques, et réutilisables pour différentes applications.

SEAMLESS integrated project aims at developing an integrated framework that allows exante assessment of agricultural and environmental policies and technological innovations. The framework will have multi-scale capabilities ranging from field and farm to the EU25 and globe; it will be generic, modular and open and using state-of-the art software. The project is carried out by a consortium of 30 partners, led by Wageningen University (NL). “This publication has been funded under the SEAMLESS integrated project, EU 6th Framework Programme for Research, Technological Development and Demonstration, Priority 1.1.6.3. Global Change and Ecosystems (European Commission, DG Research, contract no. 010036-2. Its content does not represent the official position of the European Commission and is entirely under the responsibility of the authors.” "The information in this document is provided as is and no guarantee or warranty is given that the information is fit for any particular purpose. The user thereof uses the information at its sole risk and liability."

National audience; Environmental externalities created by economic activities raise complex theoretical problems, especially in agriculture. It is crucial to master them before applying expensive corrective policies. To deal with these questions, economic theory has summoned up several approaches: the application of the standard microeconomic analysis (i.e. “Environmental Economics”), the integration of original methods and tools based on the agent’s revealed preferences into the conventional theoretical corpus (i.e. the so-called “London School”), or the exploration of new methodologies and knowledge stemming from other disciplines in particular from Natural Sciences (i.e. “Ecological Economics”). This paper presents the main specifications of these approaches, theirs contributions and theirs limits regarding agri-environmental policy instruments and design, and introduces a new methodology, namely the coupling of agro-economic models.; Les interdépendances hors marchés mobilisent de plus en plus les réflexions des économistes, mais aussi des politiques. Elles posent des problèmes théoriques très complexes, spécialement en agriculture, qu'il est important de bien maîtriser avant de mettre en œuvre des politiques correctives toujours très coûteuses en terme d'information et d’administration. Confrontée à cette question, l’analyse économique s’est fortement mobilisée soit par l’application de l’analyse microéconomique standard ("l’Economie de l’environnement"), soit par la recherche des méthodes et des outils originaux basés sur les préférences révélées des agents ("l’Ecole de Londres") ou par l’intégration des problématiques et des outils provenant d’autres disciplines notamment des sciences de la nature ("l’Economie Ecologique"). Cet article a pour objectif d’exposer la manière dont ces approches se sont développées et quels sont leurs apports et leurs limites en matière d’analyse comme en matière d’application possible à la politique agricole et ses instruments, et d’introduire une méthodologie plus spécifique celle du couplage des modèles agro-économiques, particulièrement adaptée à l'évolution actuelles des politiques agricoles, comme par exemple, la PAC avec les mesures agri-environnementales et l'éco-conditionnalité.

The interactions of water policies and agricultural policies are increasingly determinant for achieving an efficient management of water resources in many countries. In the EU, agricultural and environmental policies are seeking to converge progressively towards mutually compatible objectives and, in this context, the recently reformed Common agricultural Policy (Agenda 2000) and the EU Water Framework Directive constitute the policy framework in which irrigated agriculture and hence water use will evolve. In fact, one of the measures of the European Water Directive is to establish a water pricing policy for improving water use and attaining a more efficient water allocation. The aim of this research is to investigate the irrigators’ responses to these changing policy developments in a self-managed irrigation district in Southern Spain. For this purpose, we have developed a stochastic programming model that estimates the farmers’ responses to the application of water pricing policies in different agricultural policies scenarios when water availability is subject to varying climate conditions and water storage capacity in the district’s reservoir. Results show that irrigators are price-responsive but a similar water-pricing policy could have distinct effects on water use, farmers’ income and collected revenue by the water authority in different agricultural policy options. Water availability is a determinant factor and pricing policies are less effective for reducing water consumption in drought years. Thus, there is a need to integrate the objectives of Water Policies within the objectives of the CAP programs to avoid distortion effects and to seek a synergy between these two policies.

There is nothing new in the idea that the state is always present when capital accumulation takes place. Or that its presence is always decisive. What is more interesting is to identify the various ways in which state intervention has an influence on the economic process. In general terms, it can be said that the main role of the capitalist state is to create and guarantee the necessary conditions for the ‘normal’ development of capitalist accumulation and production.

The links relating intensification and efficiency are analysed using a model that shows how optimisation at the farm level and minimal unitary cost of production are not achieved necessarily by the same intensity of land use level. This methodological framework gives new instruments to study the effects of price policies on agricultural efficiency and to make international comparisons., L'analyse des relations entre l'intensification et l'efficacité en agriculture est abordée ici à l'aide d'un modèle permettant de montrer que l'optimum au niveau de l'exploitation et le coût unitaire de production minimal ne sont pas nécessairement obtenus au même niveau d'intensification dans l'utilisation de la terre. Ce cadre méthodologique permet de construire de nouveaux outils pour étudier les effets des politiques de prix sur l'efficacité de la production agricole et pour effectuer des comparaisons internationales., Jacquet Florence, Flichman Guillermo. Intensification et efficacité en agriculture. In: Économie rurale. N°183, 1988. pp. 49-54.

DAHBSIM is a dynamic, bio-economic model of agricultural households that was designed to be applied to a rural, developing country-setting, for the purpose of addressing questions around the biophysical constraints to on-farm agricultural productivity, and the whole-farm implications of alternative strategies to sustainable agricultural intensification. The model links socio-economic and biophysical aspects, in order to better illustrate the environmental and human welfare implications of different agricultural production practices, as they are influenced by policy-driven changes in prices of inputs or outputs, or by changes in the physical environment.

Argentine agriculture and world markets - After a long spell of stagnating agricultural exports, Argentine is gaining an important place on world markets. An analysis of the reasons for this come back., L'Argentine, après une longue période de stagnation de ses exportations agricoles est en train de reprendre une place très importante dans le marché mondial. Quelles ont été les raisons qui ont permis cette évolution ?, Flichman Guillermo. L'agriculture argentine dans le marché international. In: Économie rurale. N°162, 1984. p. 20.

En estas paginas se intenta consignar algunas experiencias de trabajo con datos censales acerca de la estructura y el desarrollo agrario, y ciertas reflexiones metodologicas sobre las implicaciones que tienen las distintas perspectivas de abordar el problema. Aunque pueda parecer excesivamente obvio, no esta de mas enfatizar la importancia de los estudios de la estructura agraria en relacion con la dinamica demografica. Sin embargo, tal como habria de surgir de la "evaluacion" de los trabajos realizados acerca del tema, es bastante poco lo que se ha producido en este sentido en America Latina. En buena medida esto puede atribuirse a los criterios teoricos que han orientado, Comenzaremos por delimitar cuales son los problemas especificos con que nos enfrentamos cuando deseamos abordar el tema de "lo agrario", para de alli plantear el marco teorico en el cual consideramos deben abordarse los estudios empiricos. de manera implicita o explicita, los trabajos realizados.

Chapitre n°1; Over the last years there has been a significant development of bio-economic models, especially those integrating biophysical (called also agronomic or cropping system models) models and economic mathematical programming models. This development was enhanced by the conjunction of several factors such as the multiplicity of objectives of new agricultural policies, the increase of demand for multi-disciplinary approaches for integrated assessment, the call for more dialogue and cooperation between scientists from diverse disciplines... However, this rich body of literature on empirical applications of bio-economic models was not followed by a clear definition of their conceptual and theoretical framework. Indeed, there is not enough literature regarding the relations between this kind of models and the economic theory, their main interest compared to conventional economic approaches, their specifications and contributions in strengthening collaboration and improving integration between different disciplines... The aim of this chapter is to develop some conceptual and theoretical issues related to the bio-economic models and to present the suitable way to use this type of approach for modelling the relations between agriculture and environment and more largely for the integrated assessment.; Au cours des dernières années il y a eu un développement important des modèles bioéconomiques, en particulier ceux intégrant des modèles biophysiques (appelés aussi agronomiques ou de croissance des plantes) et des modèles économiques de programmation mathématique. Ce développement a été soutenu par la conjonction de plusieurs facteurs tels que la multiplicité d’objectifs des nouvelles politiques agricoles, l'augmentation de la demande pour des approches multidisciplinaires d'évaluation intégrée, l'appel à davantage de dialogue et de coopération entre les scientifiques de diverses disciplines... Cependant, ce riche corpus de littérature sur les applications empiriques de modèles bioéconomiques n'a pas été suivi par une définition claire de leurs cadre conceptuel et théorique. En effet, il n’y a pas assez de littérature sur les relations entre ce type de modèles et la théorie économique, leur principal intérêt par rapport aux approches économiques conventionnelles, leurs spécifications et contributions dans le renforcement de la collaboration entre les différentes disciplines... Le but de ce chapitre est de développer quelques aspects conceptuels et théoriques liés aux modèles bioéconomiques et de présenter la manière la plus appropriée d'utiliser ce type d'approche pour la modélisation de la relation agriculture-environnement et plus largement pour l'évaluation intégrée.