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Ce papier porte sur le changement d’affectation des sols indirect attribuable à la politique européenne du biodiesel. Deux études sponsorisées par la Commission Européenne trouvent des effets surfaces fort différents pour les huiles végétales utilisées dans la production de biodiesel. La première s’appuie sur une modélisation en équilibre général calculable prenant en compte les effets directs, indirects et induits. La seconde étude, plus récente, s’appuie sur un modèle biotechnique d’équilibre partiel caractérisé par une spécification détaillée des effets indirects passant par les secteurs de l’élevage. Nous développons un simulateur économique original pour comprendre ces différences de résultats et tester leur robustesse. Nous trouvons que les effets directs et indirects sur les marchés des huiles végétales expliquent une grande partie des différences. Les effets indirects sur les secteurs de l’élevage et les effets induits sont nettement plus limités. Tous les résultats sont très sensibles aux réponses des rendements aux variations de prix. Nous trouvons que le changement d’affectation des sols indirect calculé par la récente étude est surestimée d’un facteur 5. This paper deals with the controversial indirect land use changes of the European biodiesel policy. Two studies sponsored by the European Commission finds significant, but contrasted, land use effects for the different vegetable oils used for biodiesel production. The first study uses an aggregate computable general equilibrium model capturing direct, indirect and induced effects. The second recent study uses a biotechnical partial equilibrium model offering a detailed representation of the indirect effects occurring through the livestock sectors. We develop an original economic emulator to understand the diverging key results of these studies and test their sensitivity. We find that the direct and indirect effects on vegetable oil markets explain most of the differences. We also find that indirect effects on the livestock sector and the induced effects do not significantly influence the biodiesel results. However results are critically sensitive to crop yield responses that are considerably underestimated in both studies. The cropland displacement due to the biodiesel policy computed by the recent study is overestimated by a factor of 5.

The Middle East – North Africa region (MENA) is characterized by a particularly high level of dependence on agricultural imports: 40% of its needs for agricultural products are currently being met by imports, while its dependence on cereal imports is among the highest in the world. Over the course of the past several decades, a combination of demographic growth and changes in dietary habits has led to a marked increase in food requirements. Although agricultural production in the region has increased substantially over the same period, it has been unable to keep pace with the increase in demand, partly because of limitations in terms of soil and climate and partly because of limitations in terms of agricultural policy. Regional dependence on agricultural imports is likely to continue to escalate in the foreseeable future, both as a result of ongoing demographic expansion and changes in eating habits and as a result of climate change impacts in a region already recognized as a climate “hot spot.” As a global region, the MENA region is both geopolitically complex and highly strategic. Agricultural imports place a significant burden on state budgets, and agri-food policies in the region continue to struggle with urban and rural poverty. In this situation, it is important to understand which factors within the regional agri-food system are most likely to contribute to – or, on the contrary, might help mitigate – a continued increase in agricultural import dependence. It is for these reasons that Pluriagri has commissioned, and INRA has undertaken, the study summarised here. The project began by examining historic trends (from 1961 to 2011) with regard to the resource-use balance of the regional agri-food system. Next, it analysed several potential future scenarios for the region through the year 2050. To construct the scenarios, the study made use of simulation tools that take into account the anticipated effects of climate change as well as such factors as technical innovation, improved use of irrigation, contrasting patterns in eating habits, and differential changes in demographic and economic development. These simulations suggest that dependence on agricultural imports is likely to continue to increase in the region, especially if the effects of climate change are pronounced. Taken individually, none of the three mechanisms proposed for reducing agricultural import dependence (improved agricultural productivity, moderation of dietary habits, or a reduction in food waste) is capable of correcting this trend in the Maghreb, the Middle East, or the Near East. Such mechanisms may be effective in Egypt, however, and have the potential to strengthen Turkey’s role as a net agricultural exporter.

Rabbit farming has evolved largely since the 70's, passing from a family farming (includingaround the cities) to a professional farming, allover the world. Rabbit farming is easily adaptableto many environments: from intensive indoor farming to very extensive outdoor or semi-indoorsystems. Now, humanitarian organizations are aware of the several advantages of a rabbitproduction, that could improve the quality of life, particularly to offer meat of a high nutritionalquality. Rabbit farming has several advantages to be produced around the cities. As a smallherbivorous mammals, rabbit is easy to produce in a small area (garden), with very small moneyinvestments. Rabbit could be fed without competition with human food, by giving various typesof plants, cuts, household vegetable wastes, etc. Thus, rabbit farming is already developed inurban communities, either at a small scale (family: 3 to 20 breeding does) or to a medium scalelevel (20 to 100 breeding does).

Recent research has indicated that the leading perennial energy grasses, Miscanthus giganteus and switchgrass (Panicum virgatum) may be utilized for non-thermal energy conversion. The feedstock requirements for these conversion technologies would allow the crops to be harvested early, prior to senescence, to exploit the greater higher biomass yields that occur during the autumn. Miscanthus grown at three locations in Europe was continually harvested early and maintained its high peak yield when compared to the conventional spring post-senescence yield. At one site, where the crop was continually harvested for 6 years, the early harvest yield began to decline after four years although this yield decline did not occur when the crop was adequately supplied with additional nitrogen. The two ecoptypes of switchgrass grown at locations in Europe, responded very differently to an early harvest. Lowland switchgrass at two locations could not maintain the high peak yield even with a moderate application of nitrogen. Upland switchgrass examined at one location did sustain high peak yields for 5 years of continuous early harvest without the need for additional nitrogen. The results of this study have indicated that a continual early harvest of both miscanthus and switchgrass is possible but replacement plant nutrients must be applied to the crop to revent or limit the extent of any yield decline. Proceedings of the 23rd European Biomass Conference and Exhibition, 1-4 June 2015, Vienna, Austria, pp. 61-67

Agroforestry systems (AFS) are complex to model mainly due to the high spatial variability induced by the shade trees. Recently, the microclimate and lighf heterogeneity issue in AFS has been addressed using the 30 ecophysiological process-based model MAESPA (Charbonnier et al., 2013; Vezy et al., 2018). MAESPA surpassed the classical sun/shade dichotomy in AFS (Charbonnier et al., 2014) and provided continuous maps of e.g. available light, light-use~ fficiency and canopy temperature within Coffea Agroforestry Systems (GAS). A step further was to design a crop model for Coffea grown under agroforestry that would benefit from this continuum to estimate ecosystem services on the long term and under climate change scenarios. We designed DynA_Cof, a new process-based growth and yield model to compute plot-scale net and gross primary productivity, carbon allocation, growth, yield, energy, and water balance of GAS according to shade tree species and management, while accounting for fine-scale spatial effects using MAESPA metamodels (Figure 1). DynA_Cof satisfactorily simulated the daily plot-scale gross primary productivity (RMSE= 1.69 gc m-2 d-1 on 1562 days) and the energy and water balances (RMSE: AET = 0.63 mm d-1 , H= 1.27 MJ m-2 d-1, Rn= 1.98 MJ m-2 d-1) compared to measurements from an eddy-flux tower in Aquiares (Costa Rica) and also the NPP for above and below-ground organs, coffee bean yield and shade tree wood production compared to a comprehensive database from this site.

In the current context of climate change, sea-surface temperature variation, sea level rise and latitudinal shifts of currents and hydrological fronts are expected to affect marine biodiversity of the sub-Antarctic Islands, particularly in coastal waters. Characterising the impacts of climate change on marine communities requires recording environmental modifications through the establishment of long-term monitoring. PROTEKER aims at the establishment of a submarine observatory consisting of multi-disciplinary research: oceanography, habitat mapping and species inventories, genetic, eco-physiological and trophic analyses. It also aims to provide scientific standards for the management of the Kerguelen Marine Reserve. Eighteen sampling sites of previous programs were revisited by scuba diving among which eight were selected for monitoring and were progressively equipped. ROV observations and beam trawling have also been conducted for contextualisation. These sites (Morbihan Bay (4), North (2) and South (2) coast) are monitored using photo/video surveys, temperature and salinity sensors, and settlement plots. Sessile communities collected on settlement plots will be characterised yearly through morphological and DNA techniques. Phylogeographical studies of target taxa are being conducted to improve our knowledge of endemicity and connectivity levels among sub-Antarctic islands. {"references": ["F\u00e9ral (J.-P.), Poulin (E.), Gonz\u00e1lez-Wevar (C.A.), Am\u00e9ziane (N.), Guillaumot (C.), Develay (E.), Sauc\u00e8de (T.) 2019. Long-term monitoring of coastal benthic habitats in the Kerguelen Islands: a legacy of decades of marine biology research. In: Welsford, D., J. Dell and G. Duhamel (Eds). The Kerguelen Plateau: marine ecosystem and fisheries. Proceedings of the Second Symposium. Australian Antarctic Division, Kingston, Tasmania, Australia. ISBN: 978-1-876934-30-9, pp 383-402, doi : 10.5281/zenodo.3249143."]}

D'ici 2050, l'agriculture devra répondre à une augmentation de la demande alimentaire, due à une augmentation de la population qui devrait atteindre alors les 9 milliards. A l'échelle nationale, cela représente des enjeux de compétitivité et de croissance économique. Par ailleurs, afin d'assurer cette augmentation de la production, il y a deux solutions : augmenter la proportion des terres agricoles au détriment des écosystèmes naturels; et augmenter la productivité agricole. A travers une revue d'articles agronomiques et économiques, nous montrons l'importance de considérer la qualité du sol dans la productivité et la durabilité des exploitations agricoles. Cependant les pratiques agricoles préservant la qualité du sol ne sont pas largement adoptées, ce particulièrement en France. Une analyse économique de ces enjeux permet d'appréhender le processus de décision des agriculteurs, et de déterminer quelles sont les stratégies optimales permettant de répondre à ces enjeux. Nous proposons un modèle de contrôle optimal qui illustre les liens entre les pratiques agricoles et la qualité du sol, quand la qualité du sol est considérée comme un facteur de production endogène. L'intérêt et l'originalité de cet article est d'associer différentes disciplines pour étudier le rôle de la qualité du sol dans la durabilité et la rentabilité des exploitations. Agriculture is facing an expected increase in food production demand, caused by an increased global population of 9 billion people by the middle of this century. At national scale, competitiveness and economic growth issues are at stake. To insure this increase in production, there are two solutions: extend the proportion of agricultural lands at the expense of natural ecosystems; and increase agricultural productivity. Through a review of agronomic and economic articles, we show the importance of considering soil quality in the productivity and sustainability of farms. However, farming practices preserving soil quality are not widely adopted, particularly in France. An economic analysis of these issues provide an understanding of farmers' decision making process, and indicate what the optimal strategies can be to cope with these challenges. We propose an optimal control model that illustrates the links between farming practices and soil quality when soil quality is considered as an endogenous production factor. The interest and originality of this article is to associate different disciplines to investigate the role of soil quality in the sustainability and profitability of farms.