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International audience; Nowadays, the sustainability of Greek dairy cattle farms is questionable due to low competitiveness and high GHG emissions. In this context, the BIOCIRCULAR project, funded by the EYDE ETAK, developed a series of alternative practices focusing on precision agriculture principles. However, the adoption of any practice from farmers is not a given, and depends on several determinants. Hence, the objective of this study is to examine farmers’ adoption decisions regarding precision-agricultural practices in Greek dairy production systems, as well as the economic and environmental impacts of this adoption. In order to achieve this, a bio-economic model was developed based on mathematical programming methods. The proposed model simulates a large number of dairy cattle farms with or without crop production, including different management strategies and their relevant costs, and provides an environmental assessment of the adopted practices based on GHG emissions. Moreover, in order to analyze farmers’ adoption decisions, different policy measures, linked to various environmental outcomes, were examined. The results highlighted that the adoption of precision-agricultural practices led to significantly better economic and environmental outcomes. Furthermore, it was found that different levels of incentives can be efficiently targeted to encourage the adoption of new feeds and, more broadly, to secure the sustainability of the sector.

En élevage laitier, la réforme est un outil complexe, du fait de la multiplicité des paramètres desquels elle dépend, qu’il est important de maîtriser. Elle a un impact sur les capacités zootechniques et économiques de l’élevage, mais aussi sur le bien-être animal du troupeau. En effet, elle dépend non seulement de critères globaux, tels que la prévalence des boiteries, ou des mammites dans l’élevage, mais aussi de critères individuels tels que la production laitière, la parité, le stade de gestation, et le stade de lactation d’un animal. Ainsi, le modèle d’optimisation bioéconomique DairyHealthSim® permet de déterminer à travers des compromis de temps, d’exposition aux antibiotiques et de longévité, les optimums économiques par le biais de la simulation de différents scénarios. Les résultats montrent que le principal axe de réforme ayant un impact sur les résultats bioéconomiques de l’atelier est celui de la production. Un compromis doit cependant être trouvé afin de concilier santé et longévité du troupeau.

This Ph.D. thesis studies crop-livestock complementarities enabled by legumes in the region of western France. Economic and environmental assessment of these complementarities is performed from the farm scale to the regional scale. The main contribution of this research is the development of the bio-economic model SYNERGY, which represents local exchanges of crops (including legumes) and manure between crop-oriented farms and livestock-oriented farms. This model represents the pre-crop effect of legumes and includes alternative rations with these high-protein crops. The main simulation results show that coupled subsidies to legumesincrease their production but do not lead to better valuation of technical complementarities. One way to increase the use of legumes in animal feed is to label GMO-free animal products. However, since the simulated local exchanges of legumes remain low, these crops are largely imported from outside the region. Thus, the economic and environmental results do not improve at the regional scale, and protein self-sufficiency decreases.Finally, at the scale of the agro-food chain, exchanges of legumes lead to high transaction costs, which current contracts reduce only slightly. Developing markets that value local resources could foster legume production.increase their production but do not lead to better valuation of technical complementarities. One way to increase the use of legumes in animal feed is to label GMO-free animal products. However, since the simulated local exchanges of legumes remain low, these crops are largely imported from, Cette thèse de doctorat porte sur les complémentarités culture-élevage permises par les légumineuses, dans la région de l'Ouest de la France. Une évaluation économique et environnementale de ces complémentarités est réalisée depuis l’échelle de l’exploitation agricole jusqu’à celle de la région.Le principal apport de cette thèse est l’élaboration d’un modèle bioéconomique SYNERGY qui modélise les échanges locaux de cultures (dont les légumineuses) et d’effluents entre des exploitations de grandes cultures et des exploitations d'élevage. Ce modèle prend en compte l’effet précédent des légumineuses et comprend des rations alternatives avec ces cultures riches en protéines. Les principaux résultats de simulation montrent que les aides couplées aux légumineuses accroissent leurproduction mais n’engendrent pas une meilleure valorisation des complémentarités techniques. Un moyen d’accroître l'utilisation de légumineuses en alimentation animale est de labelliser les produits animaux sans OGM. Cependant, les échanges locaux simulés restant faibles, les légumineuses sont en grande partie importées de l’extérieur de la région. Ainsi, les résultats économiques et environnementaux ne sont pas améliorés à l’échelle régionale et l'autonomie en protéines diminue. Enfin, à l’échelle des filières, nous montrons que les échanges de légumineuses engendrent des coûts de transaction élevés, peu réduits par les contrats existants. Le développement de marchés valorisant les ressources locales pourrait encourager la culture de légumineuses.

This Ph.D. thesis studies crop-livestock complementarities enabled by legumes in the region of western France. Economic and environmental assessment of these complementarities is performed from the farm scale to the regional scale. The main contribution of this research is the development of the bio-economic model SYNERGY, which represents local exchanges of crops (including legumes) and manure between crop-oriented farms and livestock-oriented farms. This model represents the pre-crop effect of legumes and includes alternative rations with these high-protein crops. The main simulation results show that coupled subsidies to legumes increase their production but do not lead to better valuation of technical complementarities. One way to increase the use of legumes in animal feed is to label GMO-free animal products. However, since the simulated local exchanges of legumes remain low, these crops are largely imported from outside the region. Thus, the economic and environmental results do not improve at the regional scale, and protein self-sufficiency decreases. Finally, at the scale of the agro-food chain, exchanges of legumes lead to high transaction costs, which current contracts reduce only slightly. Developing markets that value local resources could foster legume production., Cette thèse de doctorat porte sur les complémentarités culture-élevage permises par les légumineuses, dans la région de l'Ouest de la France. Une évaluation économique et environnementale de ces complémentarités est réalisée depuis l’échelle de l’exploitation agricole jusqu’à celle de la région. Le principal apport de cette thèse est l’élaboration d’un modèle bioéconomique SYNERGY qui modélise les échanges locaux de cultures (dont les légumineuses) et d’effluents entre des exploitations de grandes cultures et des exploitations d'élevage. Ce modèle prend en compte l’effet précédent des légumineuses et comprend des rations alternatives avec ces cultures riches en protéines. Les principaux résultats de simulation montrent que les aides couplées aux légumineuses accroissent leur production mais n’engendrent pas une meilleure valorisation des complémentarités techniques. Un moyen d’accroître l'utilisation de légumineuses en alimentation animale est de labelliser les produits animaux sans OGM. Cependant, les échanges locaux simulés restant faibles, les légumineuses sont en grande partie importées de l’extérieur de la région. Ainsi, les résultats économiques et environnementaux ne sont pas améliorés à l’échelle régionale et l'autonomie en protéines diminue. Enfin, à l’échelle des filières, nous montrons que les échanges de légumineuses engendrent des coûts de transaction élevés, peu réduits par les contrats existants. Le développement de marchés valorisant les ressources locales pourrait encourager la culture de légumineuses.

Les résultats économiques des élevages porcins dépendent des prix du porc et des matières premièresalimentaires, ainsi que des performances techniques des ateliers de production. Les coûts d'alimentation, ainsique le poids d'abattage et le taux de muscle des pièces de chaque porc interviennent dans la construction de lamarge brute. Les stratégies alimentaires et de gestion des abattages des porcs à l'engrais sont donc des facteurs clés des résultats économiques. Différents modèles et outils ont été précédemment développés pour prédire les effets des stratégies alimentaires sur les performances techniques et les résultats économiques (lnraPorc, MOGADOR ... ). Ils ont montré qu'il est nécessaire de prédire la trajectoire de croissance de chaque porc pour estimer correctement les résultats de l'atelier. Ils ne permettent cependant pas d'identifier la stratégied'alimentation optimale dans un contexte économique donné. L'objectif de ce travail était de développer un outilcapable de maximiser la rentabilité de l'atelier d'engraissement dans différents contextes économiques, enproposant le meilleur compromis entre coût d'alimentation et niveau de performance des animaux.L'outil associe un modèle bioéconomique de l'atelier d'engraissement et une procédure d'optimisation de lamarge brute moyenne par porc. Le modèle bioéconomique simule la croissance de chaque porc selon sonpotentiel d'ingestion et de croissance et selon la stratégie d'alimentation. Il calcule la marge brute moyenne parporc engraissé et les impacts environnementaux de la production (par Analyse de Cycle de Vie).La procédure d'optimisation maximise la marge brute moyenne par porc en trouvant le poids cible à l'abattage(PVa), la durée maximale d'engraissement (Dmax) et la meilleure stratégie d'alimentation biphase (BP) en termesde composition de la ration (pourcentages de deux aliments A et B formulés pour couvrir respectivement 110% et90% du besoin en lysine digestible du porc moyen à 30 kg et 120 kg de poids vif) et de poids vif moyen auchangement de phase. Cette procédure utilise un algorithme évolutionnaire adapté à la résolution de problèmesnon linéaires et discontinus (CMA-ES, Covariance Matrix Adaptation Evolution Strategy). Après une phase devalidation des conditions d'utilisation de l'outil, différents scénarios ont été explorés. Dans le contexte économique retenu pour les simulations, l'outil permet d'augmenter la marge brute de 1,33€/porc en cherchant la meilleure BP, en comparaison à un scénario de référence (SR) représenta nt les pratiques habituelles. En ajoutant PVa et Dmax aux variables de décision, l'outil propose une solution qui améliore la marge brute de 2,81 €/porc par rapport à SR. L'outil permet de maximiser le résultat économique de l'atelier d'engraissement en cherchant la meilleure séquence alimentaire biphase et la meilleure gestion des abattages. Les futurs travaux viseront à réaliser une optimisation économique et environnementale conjointe de l'atelier d'engraissement.

International audience

National audience

Les pressions actuelles exercées sur la ressource en eau et la menace potentielle du changement climatique devraient fortement influencer sa disponibilité et, de façon corrélative, la demande d’irrigation. Nous développons dans cet article une approche centrée sur l’eau comme facteur de production agricole et sur la demande française en eau d’irrigation. La méthode repose sur le couplage du modèle d’offre agricole AROPAj avec le modèle de culture STICS ainsi que sur l’obtention de cartes à haute résolution. Nous proposons d’illustrer la capacité du modèle à enrichir l’analyse spatiale de la demande d’irrigation et des disparités régionales. Focalisée sur les principales de cultures de vente, l’étude montre l’importance des cultures très consommatrices d’eau d’irrigation dans les zones fortement irriguées à l’ouest et au sud-est de la France. Elle montre également dans quelle mesure le modèle peut traiter de l’importance que peut prendre l’irrigation dans d’autres régions dans un contexte de changement climatique prononcé., Present pressures on the water resource and the potential threat of climate change should strongly impact water availability and, consequently, irrigation demand. In order to help public decision-makers, we develop an approach where water is modeled as an input, and assess water demand in France. The method combines the economic model AROPAj, the STICS crop model, and the generation of high-resolution maps. As an illustration of the possible outputs of our modeling approach, we propose an application based on the spatial analysis of irrigation demand and regional disparities. This study reveals highly irrigated areas in the west and south-east of France, explained by the establishment of water-intensive crops like maize and sunflower. More importantly, it highlights the model capacity to enlighten the complex linkage between climate change and the demand for irrigation water even in regions where crops are not strongly water-intensive.

À la fin du financement par l’AFD du programme de recherches qui a été dévolu au PNRC et dont la réalisation a fait appel aux scientifiques de l’IRD et aux armateurs du GAPCM, un bilan contrasté mais qui nous paraît globalement positif peut en être tiré. Tous les engagements d’études ont pratiquement été tenus, que ce soit en biologie, en dynamique des populations et évaluations des niveaux d’exploitation, en économie, même si dans certains cas on aurait pu espérer faire mieux au regard des e...

UMR SYSTEM : équipe AMPLUS; To improve agriculture faced with regional sustainability issues, agricultural landscapes providing a diversity and high level of ecosystem services are necessary. We have developed and tested the MOSAICA-f framework to build innovative multi-functional agricultural landscapes that can consider explicitly: 1) the performance of cropping systems at the field scale, 2) farmers' decision processes on the adoption of cropping systems, and 3) possible scenarios for innovations and policy changes at the regional scale. This framework is based on a scenario approach that encompasses normative, exploratory and optimized scenarios to assess the relevance of combinations of new agricultural policies, changes to the external context (market and regulations) and innovations in cropping systems. The impacts of these changes on sustainability issues are simulated using the regional bioeconomic model MOSAICA for farmers' decision processes regarding the adoption of cropping systems at the field scale throughout a region. Applied in Guadeloupe (French West Indies), the MOSAICA-f framework enabled the design of a scenario increasing agricultural added value, food and energy self-sufficiency, employment and the quality of water bodies and reducing greenhouse gas emissions. This sustainable scenario combines new cropping systems tuned to farm types with a reorientation of subsidies, an increased workforce and banning food crop production on polluted soils. It can be used to understand the potential contribution of agriculture to sustainability issues and to help local decision makers define policies that will account for the spatial diversities of farms and fields in a landscape. Beyond the design of such a win-win scenario, MOSAICA-f has revealed trade-offs in the provision of services by agriculture.

Objectives (1) To quantify the contribution of the French forest-wood product chain in terms of carbon sequestration and substitution when accounting for both the physical impacts (shifts in tree growth and mortality rates) and the market impacts (increased demand of harvested wood products (HWP)) of climate change (cc) and the subsequent forest managers adaptations; (2) To assess the uncertainty of the impacts on the above carbon balance and on forest allocation; and (3) To assess the role of managers’ expectations toward these future, uncertain but highly anticipated, impacts. Methodology We used a bio-economic model of the French Forest Sector (FFSM++) that is able to consider and integrate: (a) the effects of climate change over forest dynamics; (b) forest investment decisions (among groups of species) according to expected profitability; and (c) market effects in terms of regionalised supply, consumption and trade of HWP, depending on the forest resource stocks and international prices. By including both forest dynamics and forest products, we can evaluate the carbon balance taking the following elements into consideration: (a) carbon sequestered in live and dead biomass in the forest; (b) carbon sequestered in HWP; (c) carbon substituted when wood is used in place of fossil fuels or more energy-intensive materials; and (d) carbon released by forest operations. Results When the model is run at constant conditions for the next century, the average carbon potential of French forests is 66.2–125.3 Mt CO 2 y −1 , depending on whether we consider only inventoried wood resources, HWP pools and direct energy substitution, or if we also account for the carbon stored in tree branches and roots and if we consider the more indirect, but also largely more subjective, material substitution. These values correspond to 18.3% and 34.7%, respectively, of the French 2010 emissions (361 Mt CO 2 ). However, when we consider both the probable increment of coniferous mortality and changes in forest growth, plus the rise in HWP demand worldwide, the average sequestration rate of the French forest decreases by 6.6–5.8% to 61.8–118.0 Mt CO 2 y −1 . Running partial scenarios, we can assess the relative interplay of these two factors, where the price factor increases the HWP stock while decreasing the forest stocks (where the latter effect prevails), while the physical impact of climate change reduces both, but to a lesser extent. Considering short-sighted forest managers, whose behaviour is based uniquely on the observed conditions at the time decisions are made, we obtain a limited effect of the overall carbon balance but a relatively large impact on the area allocation of broadleaved vs. coniferous species.

Climate change, food security, water scarcity and environmental sustainability have all become major global challenges. As a consequence, improving resource use efficiency is an important aspect of increasing crop productivity. Crop models are increasingly being used as tools for supporting strategic and tactical decision making under varying agro-climatic and socioeconomic conditions. These tools can also support climate change assessment and the evaluation of adaptation strategies to limit the adverse impacts of climate change. In this paper, the authors report on a case study conducted to assess the potential impact of climate change on grain yield in sunflower under arid, semi-arid and subhumid conditions in the Punjab region of Pakistan. Experimental data obtained between 2008 and 2009 were used for model evaluation. The study focused on the impacts of incremental temperature change on sunflower production. The modelling suggests that grain yield could reduce by up to 15% by the 2020s with an average increase in temperature of +1°C, and by up to 25% if temperatures increased by up to 2°C for the 2050s. Adaptation strategies showed that, if the crop were sown between 14 days (for 2020) and 21 days (for 2050) earlier than the current date (last week in February), yield losses could potentially be reduced.

National audience

Accepté 01/09/2016JEL classification: C61; C63; Q10; Q11; Cet article expose une méthode de calcul des prix fictifs de biens entièrement recyclées sur l'exploitation agricole lorsque ces prix affectent la productivité elle-même, dans le cadre d'un modèle de programmation mathématique linéaire de l'exploitation agricole. Lorsqu'un produit (respectivement un facteur de production) est ré-utilisé sur l'exploitation, sa valeur économique est supérieure (respectivement inférieure) au prix de marché quand le marché existe. Que ce prix de marché existe ou non, cette valeur est nécessaire lorsque le modèle requiert de calculer la productivité marginale à partir d'un rapport de prix. Les auteurs montrent qu'une méthode numérique itérative simple peut être mise en oeuvre pour calculer les prix fictifs et plus généralement l'optimum économique sans qu'il soit nécessaire de modifier la structure linéaire du modèle.

T4. What’s new with bioeconomic models for the analysis and design of agricultural systems?; International audience; Many innovations at cropping system level impact the whole farm system by changing the flow of farm resources across farm activities. Using farm models has increasingly been proposed for assessing the feasibility of prototypes of cropping systems at farm level, and evaluating their impacts on household food production, farm income, and the environment. Such models are often called bio-economic model as a way to stress the mixing of knowledge about the biophysical and economic aspects of farming (Janssen & van Ittersum, 2007; Thornton & Herrero, 2001). A priori, one should not expect accurate predictions from these coupled bio-economic models, because of their complexity and the difficulty of measuring certain key input variables, such as labour availability for the different farm and off-farm activities, family income, and intra-farm consumption of agricultural products. This type of models can rather be used to explore ‘what if’ scenarios and to understand their outcomes including their inevitable uncertainty. In this paper, we review our experience with bio-economic farm models as virtual test benches for evaluating “cropping systems ideotypes” (CSI), i.e. idealized cropping systems proposed as alternatives to existing cropping systems, for increasing farm income and production or for reducing negative impacts of farming on the environment. Six published case studies are used. The objective is to examine to what extent the models developed fulfilled their purpose of evaluating prototypes of cropping systems for farming systems design.

National audience; Agricultural landscapes drive the provision of several ecosystem services. These landscapes are the partial results of farmer cropping system choices at the field and farm levels. Cropping system choice is driven by a range of parameters that act at the field, farm and regional scales such as biophysical parameters, farm structure and regional quotas. Bioeconomic models can assess ex ante the impacts of policies on landscapes resulting from the modification of farmer choices. They have scarcely been used for assessing new spatially-explicit agricultural landscapes with the integration of the field, farm and regional scales (Delmotte et al., 2013). To assess the effects of policies on the landscapes change and the regional sustainable development, we built a regional, spatially explicit, multi-scale bioeconomic model of farmer cropping system choices. The model is tested in Guadeloupe, a French archipelago in the Caribbean islands. The Multi-scale model of the crOpping Systems Arrangement and Its Contribution to sustAinable development MOSAICA produces new agricultural landscapes at the regional scale by optimising the allocation of cropping systems regionally at the field scale. It accounts for the constraints and opportunities at the field level (e.g. soil types), the farm level (e.g. the availability of production factors), and the regional level (e.g. the policies implemented). The inputs of MOSAICA are i) the geographic database of fields, ii) the database of activities that describe the cropping systems that can be allocated to fields and iii) a farm typology. The geographic database is composed of fields represented by polygons with relevant information for the cropping system allocation defined with geographical information systems, statistical data or farm surveys. The activities are cropping systems defined with technical coefficients and externalities derived from previously published papers, relevant documentation or expertise from local advisers. The farm typology is built with a classification tree that can help observe farming system changes across scenarios. For each farm type a risk aversion coefficient is allocated and used as the calibrating parameter of the model. The model optimizes the overall farmer's utilities, which includes the revenue and the risk aversion coefficient which is the calibrating parameter, similar for all the farms initially classified in the same type. The allocation of cropping systems is modelled through a set of equations that model the choice of cropping systems by farmers at different scales, namely the field, farm, sub-regional and regional scales. The prediction capacity of the model was assessed in Guadeloupe at field and regional scales by comparing the initial crop areas and the simulated ones and the initial and observed farm types at farm scale. The outputs of the model are the new agricultural landscape and the calculation of 19 sustainability indicators. These indicators assess the impact of agriculture on society and environment at a regional scale by accounting for cropping system externalities at plot scale and the location of these cropping systems throughout the region by using scale change methods. As an illustration of its possible interest, we used the model to assess the consequences of three scenarios accounting for expected future modifications of subsidies. In the “area reallocation” scenario, the subsidies are reallocated to each crop with an amount of 1768€.ha-1. The “workforce reallocation” is the reallocation of subsidies per unit of workforce with an amount of 15569€ per worker. The “decoupling” scenario is the decoupling of subsidies from production. Results from the evaluation were good at all the scale tested (similarity of 91% at regional scale, 80% at farm scale and 75% at field scale) which means that the model can be used for scenario analysis. The scenario modified the repartition of cropping systems in landscapes in a spatially explicit way. The results are summarized in this abstract at the regional scale.The general trends observed throughout the three scenarios demonstrate a sharp decrease in sugarcane and banana production over the island with their total disappearance in the "area reallocation" scenario and in the "decoupling" scenario only for banana farms. By contrast, the areas devoted to pasture and fallow fields increase and the area devoted to crop gardening and orchards increase more progressively, as well. The consequences of these new landscapes are assessed based on spatially explicit indicators at the regional scale. In terms of economic sustainability, these three developed scenarios were relevant because they performed better than the base year in terms of economic sustainability especially the “area reallocation” scenario with the increase of the agricultural added value to 138M€.yr-1 and the decrease of subsidies to 60M€.yr-1. For social sustainability, the scenarios performed better in terms of food self-sufficiency, especially scenario 3, with an increase of nearly 50% in food-self-sufficiency. In focusing on environmental sustainability, the pressure on biodiversity and water resources decreased over the three scenarios. The modelling of farmers cropping system choices and the creation of agricultural landscapes resulting from the modification of a set of rules at different spatial scales is useful for the prototyping of landscapes. This multi-scale modelling is especially important for addressing sustainability issues, such as food security or biodiversity preservation that require multi-scale strategies for resolution. Our set of indicators can even assess the trade-offs in the provision of services by displaying the direction of change in the indicator value between the base year and the scenarios. The bioeconomic model MOSAICA integrates the different scales involved in the decision-making process of farmers and policy makers, id est the plot, farm, sub-regional and regional scales. This integration of agricultural systems allows for the testing of the multi-scale policy and parameter changes that are involved in agricultural production and the assessment of these changes on the provision of ecosystem services with spatially explicit indicators. Our model could be relevant for testing spatially targeted policies aimed at improving the contribution of agriculture to sustainable development.

International audience; Farming system design needs to adopt a landscape perspective in order to better respond to sustainability issues at the regional scale. Thus, we built a method at the regional scale to design agricultural land systems accounting for field characteristics and farm diversity, current farming systems and cropping systems, and the ecological processes (e.g. pollution of water bodies) at the regional scale. This method encompasses the definition of a farm typology to approach farmer's decision processes in term of cropping system choice. This farm typology is integrated within a regional bioeconomic model that produces new agricultural land systems by simulating farmers' decision processes in term of cropping system choices at plot scale, within the entire region. These new agricultural land systems are assessed with a set of indicators to provide information on their response to sustainability issues. This model coupled to the indicators are used within a scenario route to provide information on the relevance of combination of agronomic, economic, social and environmental levers to improve the contribution of agriculture to sustainable development. The method is applied in Guadeloupe for prototyping agricultural land systems that improve the response of agriculture to economic, social and environmental challenges with levers such as "agro ecological crop-gardening cropping systems", "energy crop", "changes in crop subsidies" and "availability of experienced workforce in farms". This method could be used in the Caribbean islands to help decision-makers improve the response of agriculture to sustainability challenges such as reaching food self-sufficiency, increasing employment and decreasing environmental impacts of agriculture. Coupling this approach to land use change study could provide a way of designing future sustainable islands.

National audience; La demande globale en bois industriel est en expansion et continuera d’augmenter avec des accroissements annuels projetés de l’ordre de 1,3 à 1,8 % jusqu’à l’horizon 2030 en lien avec l’augmentation de la population, les dynamiques de croissance économique (Chine, Inde, Asie du Sud-Est, Amérique du Sud..), les besoins en biomasse pour les filières traditionnelles, pour l’énergie en Europe ou plus largement le développement des nouveaux marchés de la bio-économie. Compte tenu des risques climatiques à venir, des pressions démographiques et foncières, et de l’évolution des demandes sociétales en produits et services forestiers, les disponibilités futures des ressources forestières seront très variables selon les régions du globe et leur potentiel d’augmentation et de mobilisation pour faire face à des besoins industriels croissants en biomasse sera principalement limité aux zones à forte productivité dans le cadre de systèmes de gestion intensifiés.

In order to seek opportunities to mitigate emissions of greenhouse gases, increase carbon sequestration and build capacity of agricultural systems to adapt to climate change, innovative climate smart agricultural landscapes satisfying multiple sustainability goals have to be designed. Whereas several qualitative methods have been proposed to design new agricultural landscapes, we lack a holistic, quantitative, spatially explicit and integrated modelling framework to design new agricultural landscapes as a function of adaptation strategies. In this paper, we propose such a modeling framework, based on a scenario approach coupled to an optimization model which prototypes cropping system mosaics at the landscape scale. The finality of the modeling framework is to identify levers for building climate smart agricultural landscapes. To simulate the land use change, our modelling framework includes a bio-economic model that explicitly accounts for scenarios of 1) policies, markets and sustainability issues, 2) farmers’ decision process and 3) cropping system performances at the field scale, under heterogeneous socio-economic and biophysical farming situations. The modelling framework also includes a set of indicators aimed at assessing quantitatively the ability of the designed landscapes to be climate-smart. The implementation of the framework in Guadeloupe, a 1800km2 tropical island, proved to be relevant since we designed prototypes of climate-smart agricultural landscape satisfying the several sustainability goals targeted: climate change adaptation, sequestration of soil C, the increase in food and energy self-sufficiency and the decrease of the risk of pollution in water catchments. By providing quantitative information on the impacts of adaptation scenarios and on the trade-offs that have to be made, the framework can help policy makers to build a “triple win” climate-smart agriculture increasing food security, adaptation and mitigation.

National audience

Purpose – From the perspectives of the probable replacement of the national calamity funds by multi-peril grassland insurance, the purpose of this paper is to estimate demand for grassland production insurance. Design/methodology/approach – A discrete stochastic programming model with a three-year planning horizon was used to run simulations for farms raising suckler cows primarily with grasslands. In this model, the annual area insured and some production decisions are optimized under grasland yield uncertainty, with possible ex post production-system adjustments. The effects of insurance loading cost (14 levels), insurance coverage level (three levels), risk aversion (two levels) and stock levels (forage and animal stocks vary according to grassland yields and to farm management of the previous years) were analyzed. Findings – The results show that grassland insurance could be used as a flexible risk management tool, when farm becomes vulnerable to fodder shortfall. According to previous years’ grassland yields and to the subsequent states of hay stock and animal liveweight, the area insured could vary between nearly the none and full. Farmers with low-average stocking rate and important hay storage capacity have less incentive to buy grassland insurance. The author also demonstrates that for a given loading cost, more insurance is purchased at a coverage level of 70 percent of average yield than at higher coverage levels. The cost of self-insurance increases for important and rare losses while multi-peril grassland insurance premium decreases. Higher levels of risk aversion also raise the quantity of insurance subscribed. Eventually, insurance price is a key factor. Almost no insurance is bought for loading costs greater than 1.1 under low-risk aversion and for loading costs greater than 1.3 under moderate risk aversion. Research limitations/implications – The willingness to pay for insurance could have been overestimated for different reasons. First, basis risks have not been introduced in the simulation framework. Although the Forage Production Index performed quite well, basis risks are high enough to trigger inappropriate indemnifications in some cases. Consequences of these risks should be estimated in further research. Second, other self-insurance options and public emergency measures such as subsidized loan or reduction in social security contributions should also be considered to assess and reduce farmers vulnerability to risks. Practical implications – The launching of the multi-peril grassland insurance is likely to be successful thanks to the 65 percent of public subsidies on insurance premiuml. However, considering that the loading cost is likely to be high and that demand for grassland production insurance is rather low, multi-peril grassland production insurance may struggle to continue unsubsidized. Originality/value – This paper provides a framework that enables to estimate demand for grassland production insurance factoring in substitution with self-insurance and taking into account successive risks.

Species' interactions and the involvement of fishermen in several fisheries may not be properly accounted for by regulatory schemes,thus making regulation suboptimal. Being the only implementable instruments, the degree of ineffciency of three second-best instruments is assessed (by using a bioeconomic multispecies model) in terms of their ability to get close to socially optimal effort and stock levels. The type of regulation and the existing biological interaction are also shown to result in different impacts on effort re-allocation: a specific regulation does not necessarily increase the pressure on the unregulated species. Finally, we discuss how the choice of which second-best policy to implement is situation-specific.

International audience; Considering soil as an ecosystem, we build a simple bio-economic model with two interelated stocks. One is the soil organic matter, basis of several ecosystem services, and the other one is the stock of nutrients directly contributing to the plant's biomass elaboration. Humification process of the crops residues contributes to the SOM, while mineralisation process contributes to the stock of nutrients. The production function is a Linear Liebig with plateau. The economic part of the model relies on the long term profit maximisation in the context of private management. We retained two controls: the mineral fertilization adding to the stock of nutrients, and the rate of biomass given back to soil. By combining both controls, we identified management regimes and defined the set of stationaries states. Going beyong that standard step of analysis, we simulated optimal time path for differents initial conditions and different set of parameter values. We specifically focused on the role of the price of fertilizers relative to the price of the agricultural products. Results show that private management of soil natural capital drives to the quasi depeletion of SOM. As a consequence, there is a need for public incentives to promote ecosystems services non supported by market.

article présenté lors du colloque ‘Innovations Sylvicoles’ qui s’est tenu à Pierroton le 3 décembre 2014; French and European forests have been in expansion for nearly a century. Their productivity has increased and their woody biomass stock is steadily increasing. Wood harvests remain significantly below biological growth. This general statement certainly reflects a reality characterized by a great diversity of forests, their methods of management and use of the resource. The fact remains that this change is reflected in a significant increase in exploitable woody biomass. The climate, energy and environmental global challenges society faces lead to consider as a priority the setting out of the energy transition and the green economy. The development of the bio-economy, based on the use of renewable resources from living organisms, namely woody biomass is a major perspective in this direction. Significant technological innovations are expected for this sector. The objectives of intensification of forest production systems are at the convergence of the two dynamics described above. They can be achieved only if we succeed in designing and developing management methods that meet the criteria of sustainable and multifunctional management of systems, taking into account their diversity.; Les forêts françaises et européennes sont en expansion depuis près d’un siècle. Leur productivité s’est accrue et leur stock de biomasse ligneuse est en constante augmentation. Les prélèvements de bois restent nettement inférieurs à l’accroissement biologique. Ce constat global reflète certes une réalité caractérisée par une grande hétérogénéité des forêts, de leurs modes de gestion et de valorisation de la ressource. Il n’en demeure pas moins que cette évolution se traduit par un accroissement sensible de la biomasse ligneuse exploitable. Les défis planétaires climatique, énergétique et environnementaux auxquels la société est confrontée amènent à considérer de façon prioritaire la mise en en œuvre de la transition énergétique et de l’économie verte. Le développement de la bioéconomie, basée sur l’utilisation de ressources renouvelables issues du vivant, notamment la biomasse ligneuse, constitue une perspective majeure dans cette direction. Des innovations technologiques importantes sont attendues pour ce secteur. Les objectifs d’intensification des systèmes de production forestiers sont à la convergence des deux dynamiques décrites ci-dessus. Ils ne pourront être réalisés qu’à condition de concevoir et développer des modes de gestion respectant les critères de gestion durable et multifonctionnelle des systèmes, dans leur diversité.

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.

Compliance and enforcement in fisheries are important is- sues from an economic point of view since management measures are useless without a certain level of enforcement. These conclusions come from the well-established theoretical literature on compliance and enforcement prob- lems within fisheries and a common result is that, it is efficient to set fines as high as possible and monitoring as low as possible, when fines are cost- less and offenders are risk neutral. However, this result is sensitive to the assumption that fishermen cannot engage in avoidance activities, e.g., ac- tivities to reduce the likelihood of being detected when noncomplying. The paper presents a model of fisheries that allows the fishermen to engage in avoidance activities. The conclusions from the model are that, under certain circumstances, fines are costly transfers to society since they not only have a direct positive effect on the level of deterrence, but also an indirect negative effect in the form of increased avoidance activities to reduce the probability of detection. The paper contributes to the literature on avoidance activities by introducing the externality from the illegal behavior as an endogenous effect on other offenders. For an externality, that has an exogenous effect on other actors, Malik shows that fines are only costly transfers for conditional deterrence (when one actor is deterred while another actor is not). For fish- eries, we show that fines are also costly transfers under no deterrence (when no agents are deterred).

National audience; The French government and private companies are currently working on a scheme to insure grassland against unfavourable weather conditions. Objectives of this study are 1) to analyse how grassland yield insurance would substitute for self insurance in suckler cow farms, 2) to assess efficiency of these insurance options and 3) to test effects of public supports on insurance demand and profit distribution. To meet these objectives, simulations have been performed thanks to a bio-economic model applied to French suckler cow farms. Different scenarios enables to isolate effects of risk aversion and self insurance, of market insurance, of insurance premium subsidies and additional direct payments. Self insurance is defined as the reduction of animal stocking rate compared to the stocking rate of a risk neutral farmer. Self insurance alone enables to reduce profit variability by 55 % but sensitivity to extreme yield conditions remains high. Rather risk-averse farmers will use both self insurance and market insurance to secure their farm against risk. Profit variation is divided by 70 % and the lowest value of profit increased by 400 %. Market insurance can indeed cover farmers the lowest forage yield at a lower cost than self insurance. Market insurance demand varies from one year to the next according to the availability of extra forage stocks. Both subsidies on insurance premium and a raise of direct payments induce an increase of expected profit and reduce value of the lowest profit. Premium subsidies decrease also standard deviation in spite of a slight increase of animal stocking rate.

International audience

La maîtrise du mildiou et de l’oïdium de la vigne repose majoritairement sur l’utilisation systématique de fongicides. Une des voies pour limiter quantitativement le recours aux fongicides est de proposer des stratégies de décisions explicites et innovantes pour des traitements moins systématiques et appliqués aux moments les plus opportuns. Dans le cadre du projet SyDéRéT, un processus opérationnel de décision nommé Mildium® a été conçu et testé à l’échelle parcellaire durant plusieurs années dans le vignoble français. Son application permet une réduction de 30% à 50% de l’indice de fréquence de traitement contre ces deux maladies sans altérer les performances de la récolte dans plus de 90% des situations et sans entraîner un surcoût de mise en oeuvre. Des enquêtes menées auprès des viticulteurs au cours de ce projet montrent cependant que des freins techniques et économiques à l’adoption de ce type de processus existent dans les exploitations et que la diffusion de ces pratiques nécessite un accompagnement étroit des viticulteurs. Un travail de modélisation bioéconomique conduit durant ce projet, permet d'analyser l'impact potentiel en termes de risques de perte de récolte de stratégies de protection contre ces deux bio-agresseurs., In most cases, the protection of grapevine against powdery and downy mildews relies on systematic usage of fungicides. One mean to limit the amount of fungicides used is to design innovative and explicit decision strategies for treatments applied less systematically and at most opportune times. Within the SyDéRéT project, a decision workflow named Mildium® has been designed and implemented at the plot scale during several years in French vineyards. Mildium® made it possible to reduce by 30 to 50% the Treatment Frequency Index for these two diseases without altering, in more than 90% of the cases, the crop protection performance at harvest and without augmenting costs. Interviews of growers which were conducted during this project showed that technical and economical factors may hinder the adoption process for such decision tools and that technical support to growers is needed. A bio-economic model was developed during this project in order to investigate potential impacts of crop protection strategies against both diseases on crop and yield damage risks.

Scientific and Technical Research Reports: EUR 25962. Final report: FSSIM-AFRICA.; International audience; This report presents a farm household model for use in the context of developing countries 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 for impact assessment of agricultural and environmental policies on farm performances across Europe. FSSIM-Dev is conceived to be applied for family agriculture where farm household production, consumption and labour allocation decisions are non-separable due to market imperfections. Contrary to most well-known household models which are econometric-based, FSSIM-Dev is a non-linear optimization model which simultaneously solves a set of microeconomic models reproducing the behaviour of representative farm households. FSIM-Dev is designed to capture five key features of developing countries' agriculture: non-separability of production and consumption decisions; interaction among farm households for market factors; heterogeneity of farm households with respect to their both consumption baskets and resource endowments; inter-linkage between transaction costs and market participation decisions; and 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 and improved rice cropping management on the livelihood of representative farm households in Sierra Leone. Results show that both the rice support policy and the improved crop management would significantly increase rice 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.

Les quotas laitiers, instaurés en 1984, seront supprimés à horizon de 2015. A partir d’un modèle de type bioéconomique, cet article discute des principales implications productives et économiques de cette évolution importante de la Politique Agricole Commune (PAC). L’hypothèse est faite que, concomitamment à l’abandon des quotas laitiers, un système de contractualisation de type «double volume avec des prix différenciés» sera mis en oeuvre entre les producteurs et les industriels. Le modèle utilisé a pour objectif de maximiser le revenu de l’exploitation tout en tenant compte d'un ensemble de contraintes, qu’elles soient zootechniques, agronomiques, environnementales, structurelles et réglementaires. Ce modèle, qui permet d’intégrer le risque lié à la volatilité des prix, est appliqué à quatre types d'exploitations reflétant une partie de la diversité des systèmes de production localisés dans l’ouest de la France. D’après les résultats issus de cette modélisation, il apparaît que de nombreuses exploitations laitières de l’ouest disposent, moyennant une modification de leurs stratégies productives (intensification, spécialisation), d’un potentiel assez important d’augmentation de la production laitière, à structures constantes. La quantité de lait supplémentaire susceptible d’être produite dans cette région dépendra de l’évolution de la demande de produits laitiers, de la compétitivité des industries laitières et des normes environnementales. Pour une exploitation donnée, ces quantités supplémentaires sont également conditionnées au prix de vente du lait produit dans les deux volumes contractualisés et aux prix relatifs entre les produits agricoles (lait, viande bovine et céréales)., Milk quotas, introduced in France in 1984, will be ended by 2015. Based on a «bio-economic» model, this paper discusses the main productive and economic implications of this important change of the Common Agricultural Policy (CAP). We assumed that, with the abolishment of milk quotas, a contracting system of «double volume with different prices» will be implemented between producers and dairy processors. The model maximizes the farm income while taking into account a set of constraints: zootechnical, agronomical, environmental, structural and regulatory. This model, which integrates the risk of price volatility, is applied to four types of farms reflecting a part of the farms’ diversity located in West of France. According to the results of this modelling approach, it appears that many dairy farms located in this region have, thanks to changes in their production strategies (intensification, specialization), a large potential to increase milk production, with the same structure. The amount of extra milk which may be produced will depend on the evolution of demand for dairy products and the competitiveness of the dairy industries. For a given farm, these additional quantities depend on the price of milk produced in volume Aand B, the relative prices between agricultural products (milk, beef and cereals) and a possible strengthening of environmental constraints.

Agricultural systems are constantly evolving driven by technical and organizational innovations and changes in their socio-economical context. At regional scale local stakeholders can encourage and accompany foreseen changes if they can have clear visions of their potential impacts. The objective of the PhD thesis was to develop and test a framework to assist farmers and local stakeholders of a region in the building and assessment of scenarios related to agricultural systems. This framework is based on different modeling approaches for a participative, integrated, multi-scale and prospective assessment of agricultural systems. It was implemented in the Camargue region, South-East of France, with cereal farmers and local stakeholders involved in agricultural production and territorial management. Scenarios assessed were related to the reform of the common agricultural policy (CAP) of the European Union in 2012-2014, and to national objectives of reduction in pesticide use and extension of organic farming (OF). Several data and expert knowledge have been formalized and used in these simulations of scenarios. Two modeling tools have been used for scenario assessment with stakeholders: an agent-based model allowed interactive simulation sessions with farmers, and a bio-economic model was co-developed and used with local stakeholders such as the French Union of Rice Producer and Industry and the Regional Natural Park, both important stakeholders influencing local agricultural systems. Assessing scenarios related to the CAP reform showed the strong dependency of rice farms to EU subsidies. Farmers involved in the sessions tested several adaptation strategies for their farms in response to the disappearance of the rice coupled payment. These strategies often implied a diversification of production and/or the conversion to OF, but they did not allowed to compensate the economic loss due to the suppression of the rice coupled payment. At the regional level, these strategies would lead to an important decrease on the area cultivated with rice, and therefore have an impact on other related activities in the region. Diversification of production is also a key strategy in scenarios related to governmental objectives of reducing pesticide use and conversion to OF. Therefore, in Camargue, there is room for maneuver for conciliating environmental and economic objectives related to agricultural production. This thesis proposed and applied a framework for participatory integrated assessment of agricultural systems. This framework associates closely farmers and other stakeholders in all phases of scenario assessment (scenario definition, data gathering and analysis, the building and use of models). The way different modeling tools are used in this framework could contribute for collective assessment of future farming systems and support collective actions for sustainable agricultural development.; Les systèmes agricoles sont en constante évolution sous les effets conjugués d'innovations techniques et organisationnelles et de changements du contexte socio-économique. A l'échelle d'un territoire, des acteurs locaux peuvent encourager et accompagner des changements de ce type s'ils ont une vision claire de leurs impacts potentiels. L'objectif de cette thèse est d'élaborer et d'appliquer une démarche permettant d'assister agriculteurs et autres acteurs locaux d'un territoire dans la construction et l'évaluation de scénarios d'évolutions des systèmes agricoles. Une démarche basée sur des approches permettant une analyse prospective, multicritères, multi-échelles et participative d'évaluation des systèmes agricoles a été développée. Elle a été mise en oeuvre en Camargue (sud-est de la France), avec des exploitants céréaliers et des acteurs de la production agricole et de la gestion du territoire. Des scénarios portant sur la réforme de la politique agricole commune (PAC) en 2012-2014, ainsi que sur des objectifs nationaux de réduction de la consommation de pesticides et de développement de l'agriculture biologique ont été développés. Ces perspectives d'évolution des systèmes agricoles camarguais ont été évaluées, via la formalisation de nombreuses données et connaissances. Deux outils de modélisation ont été utilisés : un modèle multi-agent a permis la mise en place de séances de simulation interactives avec des agriculteurs, et un modèle bioéconomique a été développé et utilisé avec des acteurs locaux tels que le syndicat des riziculteurs et le parc naturel régional. Les scénarios portant sur la réforme de la PAC ont confirmé la dépendance des exploitations rizicoles aux subventions. Des agriculteurs ont testé différentes stratégies d'adaptation de leurs exploitations à la suppression de l'aide couplée à la production rizicole. Ces stratégies, souvent basées sur la diversification des activités ou sur la conversion à l'agriculture biologique, ne permettaient pas de compenser les pertes économiques liées à la disparition de l'aide couplée. A l'échelle du territoire, ces stratégies réduiraient fortement la surface cultivée en riz, avec des impacts importants sur d'autres activités en lien avec la production agricole. Cependant ces stratégies vont dans le sens des objectifs gouvernementaux de réduction des impacts de l'agriculture sur l'environnement. Des scénarios portant spécifiquement sur ces objectifs ont permis d'identifier des marges de manoeuvre importantes au niveau des exploitations céréalières camarguaises. Cette thèse propose un cadre pour la mise en oeuvre de démarches d'évaluation des systèmes agricoles dans un territoire, qui associe les agriculteurs et les acteurs locaux à différentes étapes, depuis leur engagement pour le choix des scénarios, l'acquisition et l'analyse des données, la construction des outils de simulation et l'évaluation de scénarios. La combinaison de différents outils de modélisation pour la réalisation de réflexions collectives, pourrait contribuer à la mise en place d'actions pour un développement durable de l'agriculture.

Part I. Chapter 1; International audience; In the last years there has been a significant development of bio-economic models, especially those integrating biophysical models and economic mathematical programming models. This development was enhanced by the conjunction of several factors such as the multiplicity of objectives in new agricultural policies, the increase of demand for multi-disciplinary approaches for integrated assessment, and the call for more dialogue and cooperation between scientists from various disciplines.

Global marine fisheries production has reached a maximum and may even be declining. Underlying this trend is a well-understood sequence of development, overexploitation, depletion and in some instances collapse of individual fish stocks, a pattern that can sequentially link geographically distant populations. Ineffective governance, economic considerations and climate impacts are often responsible for this sequence, although the relative contribution of each factor is contentious. In this paper we use a global bioeconomic model to explore the synergistic effects of climate variability, economic pressures and management measures in causing or avoiding this sequence. The model shows how a combination of climate-induced variability in the underlying fish population production, particular patterns of demand for fish products and inadequate management is capable of driving the world’s fisheries into development, overexploitation, collapse and recovery phases consistent with observations. Furthermore, it demonstrates how a sequential pattern of overexploitation can emerge as an endogenous property of the interaction between regional environmental fluctuations and a globalized trade system. This situation is avoidable through adaptive management measures that ensure the sustainability of regional production systems in the face of increasing global environmental change and markets. It is concluded that global management measures are needed to ensure that global food supply from marine products is optimized while protecting long-term ecosystem services across the world’s oceans. La producción pesquera mundial ha superado su máximo potencial y parece estar en declive. Esta tendencia es el resultado de una sucesión de desarrollo, sobreexplotación, agotamiento, y en algunos casos, colapso de los stocks pesqueros individuales. Este proceso conecta recursos distantes a nivel geográfico. Esta secuencia es a menudo atribuida al efecto combinado de una gestión deficiente, consideraciones económicas y efectos ambientales pero la influencia de cada uno de estos factores suele ser difícil de determinar. En el presente trabajo hemos utilizado un modelo bioeconómico global para explorar los efectos conjuntos de la variabilidad climática, presiones económicas y medidas de gestión para producir o evitar esta secuencia. El modelo muestra como una combinación de variabilidad de origen climático en los stocks, el aumento de la demanda de productos marinos y una gestión deficiente es capaz de dirigir las pesquerías mundiales a través de un proceso de desarrollo, sobreexplotación, colapso y recuperación similar a los patrones observados. Además, mostramos cómo el patrón secuencial de sobreexplotación puede emerger como una propiedad endógena de la interacción entre fluctuaciones regionales y un mercado globalizado. Esta situación es evitable con una gestión adaptativa de los recursos que asegure la sostenibilidad de los sistemas de producción regionales en un contexto de cambio y mercados globales. Se concluye con que una gestión global de los recursos es necesaria para garantizar la óptima producción de productos de origen marino y la conservación de los ecosistemas.

This book chapter discusses the productive and economic implications of several options for the future Common Agricultural Policy (CAP) focusing on French dairy farms (as France includes 16% of the EU milk quota). The options studied follow the proposals made by the European Commission in May 2008 for the “Health Check” of the CAP. We examine the cross effects, on the productive strategy of French dairy farms, of the phasing out of milk quotas and price variations. A bio-economic model is developed to measure the productive, economical and environmental impacts on French dairy farms of the milk quota abolition. While respecting the principle of agent rationality (maximization of profit), the model incorporates the economic risk related to the volatility of input and output prices. Thus, the model maximises the expected utility of income while taking into account a set of constraints: regulatory, structural, zootechnical, agronomic and environmental. The model is applied to four types of dairy farms to reflect the diversity of production systems in the west of France. Simulations show that French dairy farms have a strong production potential but this increase in milk volume results in an intensification of the production system and has negative effects on the environment., Ce chapitre d’ouvrage discute des implications économiques et productives de plusieurs options pour la future Politique agricole commune (PAC) en se concentrant sur les exploitations laitières françaises (la France réalise 16% du quota laitier de l'UE). Les options étudiées s’inscrivent dans la continuité des propositions faites par la Commission européenne en mai 2008 dans le cadre du bilan de santé de la PAC. Nous examinons les effets croisés, sur la stratégie productive des exploitations laitières françaises, de la suppression des quotas laitiers et des variations de prix. Un modèle bioéconomique est conçu pour évaluer les impacts productifs, économiques et environnementaux de l'abolition des quotas laitiers. Tout en respectant le principe de la rationalité des agents (maximisation du profit), le modèle intègre le risque économique lié à la volatilité des prix des intrants et des produits agricoles. Ainsi, le modèle maximise l'utilité attendue d'un revenu tout en tenant compte d'un ensemble de contraintes : réglementaires, structurelles, zootechniques, agronomiques et environnementales. Le modèle est appliqué à quatre types d'exploitations laitières afin de refléter la diversité des systèmes de production dans l'Ouest de la France. Les simulations montrent que les exploitations laitières françaises ont un fort potentiel de développement de la production, mais cette augmentation des volumes implique une intensification du système de production et peut induire des effets négatifs pour l'environnement.

The aim of this chapter is to assess the combined effects of 2003 CAP reform and nitrate directive on the sustainability of selected arable farming in Midi-Pyrénées. The nitrate directive is one of the earliest pieces of EU legislation aimed at controlling pollution and improving water quality across Europe. This impact analysis is performed through a bio-economic modelling framework coupling the crop model CropSyst and the farm-based model FSSIM. The 2003 CAP reform was compared first to the continuation of agenda 2000 regulations and then to a policy scenario combining the CAP reform with the application of the nitrate directive. The impact analysis shows that the potential 3% premium cut is not enough to compel farmers to adopt the nitrate directive and to substitute entirely the current activities by the alternative ones based on better N management. The farm income is marginally affected in spite of this premium cut thanks to the implementation of certain alternative activities which are more competitive. The impact on nitrate leaching is not always positive and swings between -6% to +5% depending on farm types. This implies that the partial adoption of better N management is not sufficient to ensure a reduction of leached nitrate. A sensitivity analysis shows that 17% of premium cut is required to enforce all arable farmers in the region to implement this directive., L’objectif de ce chapitre est d'évaluer les effets combinés de la réforme de la PAC de 2003 et de la directive nitrates sur la durabilité des cultures arables en Midi-Pyrénées. La réforme de la PAC de 2003 a été comparée d'abord à la poursuite de l'Agenda 2000 et ensuite à un scénario de politique combinant la réforme de la PAC de 2003 avec l'application de la directive nitrates. La modélisation bio-économique couplant le modèle de culture CropSyst et le modèle de ferme FSSIM a été mobilisée dans cette étude d’impact. Les résultats de l'analyse montrent qu’une pénalité de 3% n'est pas suffisante pour contraindre les agriculteurs à adopter la directive nitrates et pour substituer intégralement les activités courantes par des activités alternatives basées sur une meilleure gestion de l'azote. Le revenu agricole est peu affecté en dépit de cette pénalité grâce à l’adoption de certaines activités alternatives qui sont beaucoup plus rentables. L'impact sur le lessivage des nitrates n'est pas toujours positif et oscille entre -6% à 5% selon les types d'exploitation. Cela implique que l'application partielle de la directive n'est pas suffisante pour assurer une réduction des nitrates lessivés. Une analyse de sensibilité montre qu’un pourcentage de pénalité de 17% est nécessaire pour contraindre toutes les exploitations de grandes cultures de la région à adopter cette directive.

International audience; The bio-economic modeling approach presented in this book is a result of two distinct developments: by one side, the improvement of bio-physical simulation models applied to agricultural systems and by the other, the evolution of agricultural policies demanding a kind of assessment that conventional economic models are not able to provide. Some economists began to realize that biophysical models could be considered as detailed engineering production functions, allowing to represent in a consistent manner the joint products of agricultural activities. The perspectives that this vision provides allow dealing with environmental and natural resources issues with an economic perspective in an efficient manner. Representing environmental impacts of agricultural activities measured in physical units allows performing cost-efficiency calculations of alternative policies, potentially able to attain specified policy targets. This capability permitted in recent years the development of applied research related with institutional demands from national and international public institutions. But this approach requires a multidisciplinary approach, with positive and negative effects. The positive one is, both for economists and biophysical scientists, to enlarge their vision of the world. The negative effects are the greater difficulty to get recognized in their specific discipline, the obstacles to obtain the necessary information for properly use these models, and the longer time to perform the research activity. The “productivity” for producing papers is lower for economists applying this approach compared with economists applying econometric methods, using available published data. In spite of these negative effects, as the demands from the real world for the assessment these models are able to provide is increasing, it is quite possible that there is a future for bio-economic models applied to agricultural systems. The challenges of Climate Change, the increase care for the preservation of natural resources and the environment will require further developments of this kind of approach.

International audience; Bio-economic models can be used to assess the impact of policy and environmental measures through economic and environmental indicators. Focusing on agricultural systems, farmers’ decisions in terms of cropping systems and the associated crop management at field scale are essential in such studies. The objective of this paper is to present a study using a bio-economic model to assess the impact of the Nitrate Directive in the Midi-Pyrenees region (France) by analyzing, at the farm scale, farm income and three environmental indicators: nitrate leaching, erosion and water consumption. Two scenarios, the 2003 CAP reform (baseline scenario) and the Nitrate Directive (policy scenario), with a 2013 time horizon, were developed and compared for three representative arable farm types in the Midi-Pyrenees region. Different types of data characterizing the biophysical context in the region (soil, climate), the current cropping systems (rotation, crop management) and farm resources (irrigated land, labor) were collected to calibrate and run the models. Results showed that the implementation of the Nitrate Directive may not affect farm income. However, significant modifications to cropping systems and crop allocation to soil types were simulated. Contrary to expectations, nitrogen leaching at the farm scale did not change. Overall water consumption increased and soil erosion decreased due mainly to a modification in cropping patterns and management by soil type. This study provides an example of unanticipated effects of policy and trade-offs between environmental issues.

International audience; In the early 1980s cultivated land planted with grain legumes increased very rapidly in Europe due to specific EU policy to support protein production (premiums, funding of research and extension programs). But with the evolution of the CAP (decoupling and reduction of subsidies per ha) and international commitments (Blair House agreement with consequence of duty-free soybeans importing) the surface area set aside for grain legumes declined substantially by 78% from 1993 to 2008. Recently, several EU regions announced new premiums to boost grain legume crops. This paper presents a study using a bio-economic model to assess impacts of the economic incentive measures in the Midi-Pyrenees region (France) on legume introduction in cropping systems by analyzing, at farm level, the farm income and total energy consumption.

International audience; Decision-makers are often confronted with contradictory demands when it comes to developing projects to evaluate and foster suitable strategies for adapting to global warming. In fact, few quantitative methods for assessing the impact of climate change on resilience and adaptive capacity have been defined and used. Furthermore, the tendency has been to treat the impact of climate change as a stand-alone activity, whereas it should be integrated into development projects, plans, policies, and strategies, in order to reach a compromise solution, a trade-off between the costs and benefits of different criteria (economic, social, environmental etc.). This paper presents a study using a bio-economic model to assess, at farm level, the impact of climate change in northern Tunisia by analysing farm production systems behaviours as well as economic and environmental variables.

International audience; Organic agriculture offers an attractive framework for sustainable farming in terms of the environment, socio-economic and institutional aspects (Capitaine et al., 2009). In spite of the advantages, farmers are more often than not reluctant to convert fully to organic vineyard for they consider that, over and above any technical constraint, farm subsidies do not sufficiently compensate for the uncertain yields and market prices for their products. The purpose of this paper is to evaluate, at short-term and long-term, using a bio-economic approach, the farmer strategies in terms of production system (conventional or organic farming) given uncertainties related to prices, yields and subsidies granted to organic agriculture.

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.

Cahier du LEF ; 2010-04; The French Forest Sector Model (FFSM) jointly models the economic dynamic of the French forest sector and the biological dynamic of the French forest resource. To do so, two modules are interconnected. First, an economic module represents producers and consumers behaviors as well as the evolution of wood products prices in a partial equilibrium framework. It represents supply of primary wood products w, their conversion in final wood products p and the demand for final products p. Second a forest resource dynamics module represents forest stock in standing forest and its dynamics. The forest resource dynamics and the economic modules are linked in two. First, wood stock dynamics depend on harvesting rates which derive from the economic module. Second, in the economic module, supply functions depend on available wood stock. The FFSM is likely to become a powerful tool to assess climate policies implications for the forest sector. So far, the FFSM has been used (1) to model the impacts of fuelwood stimulating policies on the sector under uncertainty over the availability of the resource and (2) to compare the implications of two opposite policies: the payment for forest carbon sequestration and the stimulation of fuelwood demand.; Le Modèle de Secteur Forestier Français (MSFF) représente à la fois la dynamique économique du secteur forestier et la dynamique de la ressource forestière française. Pour cela il est construit sur la base de deux modules interconnectés. Tout d’abord, un module économique représente les comportements des consommateurs et des producteurs de produits bois dans un modèle en équilibre partiel. Ce module représente la demande de produits bruts w, leur transformation en produits transformés p et la demande pour ces produits transformés. Le module de dynamique de la ressource quant à lui représente le stock forestier en forêt et sa dynamique. Le module économique et le module de ressource sont doublement liés. Premièrement la dynamique biologique dépend des taux de récoltes donnés par le module économique. Deuxièmement, dans le module économique, les fonctions d’offre de bois brut dépendent de la quantité de bois disponible en forêt. Le MSFF est un outil de référence pour modéliser les implications des politiques climatiques sur le secteur forestier français. Jusqu’à présent il a été utilisé pour (1) modéliser les conséquences sur la filière de politiques stimulant la consommation de bois énergie dans un contexte d’incertitude sur la disponibilité de la ressource et (2) pour comparer les implications de deux politiques climatiques opposées : d’une part le paiement pour la séquestration du carbone en forêt et d’autre part la stimulation de la demande de bois énergie.