MOSAICA: A multi-scale bioeconomic model for the design and ex ante assessment of cropping system mosaics

International audienceTo understand the effects of policy changes on organisations and compositions of cropping systems at regional scale and their contribution to the sustainable development of regions, we built a regional, spatially explicit, multi-scale, bioeconomic model called MOSAICA. This model explicitly incorporates information at field, farm, sub-regional and regional scale to provide cropping system mosaics by way of regional optimisation of the sum of individual farmer's utilities under field, farm and territory biophysical and socio-economic constraints. Its generic structure means it can be used in different regions with geographic information on the location of the field and farm, data on cropping system performance, on location factors and on policy schemes. We used the model in Guadeloupe to test the impact of three scenarios of change on the agricultural subsidy regimes. The model produced three cropping system mosaics which reduced the area under banana and sugarcane, turned specialized banana and sugarcane farming systems into breeding systems while improving the overall contribution of agriculture to sustainable development. The spatially explicit results of changes in ecosystem services, and in farming systems with MOSAICA make it an appropriate decision-aid tool for regional planning

Formally verified optimizing compilation in ACG-based flight control software

International audienceThis work presents an evaluation of the CompCert formally specified and verified optimizing compiler for the development of DO-178 level A flight control software. First, some fundamental characteristics of flight control software are presented and the case study program is described. Then, the use of CompCert is justified: its main point is to allow optimized code generation by relying on the formal proof of correctness and additional compilation information instead of the current un-optimized generation required to produce predictable assembly code patterns. The evaluation of its performance (measured using WCET and code size) is presented and the results are compared to those obtained with the currently used compiler

How to Measure the Performance of Farms with Regard to Climate-Smart Agriculture Goals? A Set of Indicators and Its Application in Guadeloupe

Conceptualized by the Food and Agriculture Organization in 2010, climate-smart agriculture aims to simultaneously tackle three main objectives. These are increasing food security, building the resilience of agricultural systems for adaptation to climate change and mitigation of GHG. As much research focuses on one of these three objectives, our understanding of how agricultural systems address these three challenges simultaneously is limited by the lack of a comprehensive evaluation tool. In order to fill this gap, we have developed a generic evaluation framework that comprises 19 indicators that we measured in a sample of 12 representative farms of the North Basse-Terre region in Guadeloupe. The evaluation revealed clear differences in the performance of these farming systems. For example, nutritional performance varied from 0 to 13 people fed per hectare, the average potential impact of climatic conditions varied from 27% to 33% and the GHG emissions balance varied from +0.8 tCO(2eq)center dot ha(-1) to +3.6 tCO(2eq)center dot ha(-1). The results obtained can guide the design of innovative production systems that better meet the objectives of climate-smart agriculture for the study region. The evaluation framework is intended as a generic tool for a common evaluation basis across regions at a larger scale. Future prospects are its application and validation in different contexts

Evaluation ex ante de systèmes de culture innovants par modélisation agronomique et économique: de la conception à l'adoption. Cas des systèmes de culture bananiers de Guadeloupe.

Agricultural production is evolving towards systems able to provide multiple objectives in order tosatisfy the complex concerns related to sustainability, therefore leading agricultural research to bear growing interest in the development of methodologies to allow the design and assessment of innovative cropping and farming systems able to fulfil these constraints. Although the number and the diversity of tools and concepts are increasing, only few transdisciplinary research have been done, therefore limiting the development of methodologies for integrated assessment from the design to the adoption of innovations by farmers. The objective of this thesis is to propose a trandisciplinary method for ex ante assessment of innovative cropping systems in order to palliate this shortcoming in the current research. After a survey of available assessment methodologies, we propose an original method which is made of a four-step approach: i) modelling farm diversity and prototyping innovative cropping systems, ii) use of a crop model to simulate the biophysical impacts of innovations for the different farm types, iii) development of a bio-economic farm model for assessment of the impacts of the adoption of innovations at farm level, and iv) econometric modelling of adoption by farmers. The method was then applied to the design and assessment of innovative cropping systems for banana production in the French West Indies, that are currently facing severe economic and environmental crisis. The first step led to the identification of six contrasting farm types and sixteen cropping systems prototypes, invoving rotation of banana with cover crop, intercropping, and regulation of pesticide use. The second step showed that the performances of innovation may differ greatly among fram types, and some systems appear to be promising from both agronomic and environmental critera. However simulations made in step 3 and 4 showed that promising innovations at field level maight have negative impacts at farm level while some promising innovation have low probability of adoption. Results of econometric model and bio-economic simulations made possible to define a set of proposals for local research and development stakeholders in order to improve the likelihood of adoption of the innovations. In the last chapter we present a critical analysis of the advantages and shortcomings of our approach underling the genericity of the methodology, and the potential extension of its application to other context, for better matching the innovations with society and farmers demandsFace à la multiplication et la complexité croissante des objectifs assignées à l'agriculture, les méthodologies de conception et d'évaluation ex ante de systèmes de culture innovants font l'objet d'un effort de recherche très soutenu. Cependant malgré le foisonnement de recherches et de productions d'outils disciplinaires, peu de recherches d'interface ont été entreprises, ce qui limite les possibilités d'évaluations ex ante globales des systèmes innovants, de la conception à l'adoption par les agriculteurs. L'objectif de cette thèse est de contribuer à l'avancée de ces travaux, en proposant une méthode transdisciplinaire d'évaluation ex ante de systèmes de culture innovants basée sur la combinaison d'outils de modélisation issus de l'agronomie et de l'économie. A partir d'une analyse de la littérature actuelle et de ses forces et faiblesses, nous construisons une méthode originale qui se décompose en 4 étapes : i) modélisation de la diversité des exploitations et prototypage de systèmes innovants plus durables, ii) utilisation d'un modèle de culture pour simuler le fonctionnement biophysique des innovations dans les types d'exploitations, iii) évaluation des impacts de l'adoption sur le fonctionnement et les performances des types d'exploitation à l'aide d'un modèle bioéconomique d'exploitation, iv) modélisation ex ante de l'adoption par les planteurs à l'aide d'un modèle économétrique. La méthode est ensuite appliquée à la conception et à l'évaluation ex ante de prototypes de systèmes de cultures bananiers aux Antilles françaises, qui traversent actuellement une crise socio-économique et environnementale sévère. L'application de la première étape de la méthode a permis d'identifier 6 types d'exploitations très contrastés avec des problèmes de durabilité se déclinant différemment et de mettre au point 16 prototypes de systèmes innovants impliquant plante de couverture cultivées en association ou en rotation, nouvelles variétés de bananiers, et réduction de l'usage des intrants chimiques. La deuxième étape a montré que les performances agronomiques des prototypes peuvent varier considérablement d'un type d'exploitation à un autre, et que certains systèmes semblent très prometteurs sur le plan agronomique et environnemental. Cependant les modélisations réalisées en étape 3 et 4 montrent que d'une part, des innovations performantes à la parcelle peuvent poser des problèmes de trésorerie et de charge de travail à l'échelle de l'exploitation, et que d'autre part certaines innovations très prometteuses ont pourtant un taux d'adoption faible. Les résultats du modèle économétrique et des simulations réalisées en étapes 2 et 3 permettent alors de définir un ensemble de propositions d'action à destinations des acteurs de l'innovation et du développement en vue de maximiser les chances d'adoption de systèmes plus durables. Le dernier chapitre de cette thèse revient sur les forces et les faiblesses de la méthode et souligne sa généricité potentielle qui devrait donc permettre d'étendre son application à d'autres contextes afin d'assurer une meilleure adéquation entre les innovations produites par la recherche agronomique et les attentes des agriculteurs et de la société