L’organisation d’un territoire est le reflet de l’activité humaine qui y adapte la couverture du sol et son usage en fonction des contraintes ou opportunités techniques, économiques et sociétales. L’arrangement temporel et spatial des occupations du sol a une forte influence sur les risques environnementaux. Cet article présente une méthodologie à base de modèles stochastiques pour identifier, localiser et simuler les occupations temporelles des régions différenciées par leurs successions de culture dans la perspective de construction d’un modèle « neutre ». L’écart entre données simulées et observées permet de déceler des ruptures dans le processus de mise en valeur du territoire. Les données utilisées dans cette étude proviennent d’enquêtes effectuées sur l’impluvium de Vittel-Contrexéville concernant la qualité des eaux souterraines.

This paper presents a prototype of case-based reasoning, built for the agricultural domain. Its aim is to forecast the allocation of a new energy crop, the miscanthus. Interviews were conducted with french farmers in order to know how they make their decisions. Based on interview analysis, a case base and a rule base have been formalized, together with similarity and adaptation knowledge. Furthermore we have introduced variations in the reasoning modules, for allowing different uses. Tests have been conducted. Results showed that the model can be used in different ways, according to the aim of the user, and e.g. the economic conditions for miscanthus allocation.

Cet article presente un prototype de raisonnement a partir de cas developpe dans le cadre d’une application en agronomie, pour prevoir l’implantation dans les exploitations agri- coles d’une nouvelle culture energetique, le miscanthus. Des enquetes ont ete realisees pour ac- ceder au mode de decision des agriculteurs. Neanmoins, peu d’experiences etaient disponibles pour construire ce modele, ce qui nous a conduits a integrer des variantes dans le module de raisonnement, permettant ainsi des usages differents. Nous presentons quelques resultats experimentaux, puis discutons du modele et de ses usages.

Since the 50 last years, the rapid development of modern agriculture in industrialised countries has considerably affected the quality of water resources, up to the point to jeopardise the capacity of rural territories to produce drinking water. Hence, agronomy has been interested in the complex nitrate biogeochemical interactions for a long time.While agronomists are able to produce very accurate physical models of nitrate propagation at different scales, their tools have a limited relevance if the information regarding geology or agriculture is missing. Consequently, in many cases, it prevents the specialists of being affirmative about the prediction of their current actions on the water quality. By opposition, a system identification methodology is here presented to predict nitrate concentration in water. It has the advantage of being applicable even when very little knowledge is available. It will be shown how external variables such as rainfall and temperature can play an important role in modelling water pollution systems. The efficiency of the approach, both in terms of prediction and physical insight, is discussed on a real life dataset.

Porous cup samplers and drainage samplers are two of the broadly used techniques to monitor soil water for agronomical studies. This study provides further insight into the sample signification of these two sampling techniques. For that purpose, temporal variations of soil water δD and δ18O values collected by these two techniques have been monitored for an experimental field studied by INRA. The stable isotope data acquired provide further evidence that soil water samples collected by these two techniques are not equivalent and correspond to different water dynamics in soils: 1) quick infiltration along preferential flow paths for drainage (short residence time) and 2) water with longer residence time for porous cups. This implies that stable isotopic tools could be useful to provide additional information to “classical” monitoring of soil water. This could be of particular interest to estimate the residence time of soil water and could be relevant to follow the effectiveness of agricultural pressure reduction programs on natural water ecosystems.

Debut 2013, les auteurs de cet article ont ete conjointement sollicites par l’Etat pour donner un avis sur la methode de compensation des atteintes aux zones humides proposees pour le projet d’aeroport du Grand Ouest a Notre-Dame-des-Landes en Loire-Atlantique. Cet article fait etat des reflexions consecutives a ce travail qui, au-dela du cas aborde, portent sur les methodes a utiliser pour compenser les atteintes aux zones humides alterees, degradees ou detruites par un amenagement. Il presente tout d’abord le cadre juridique actuel de la compensation ; puis l’experience internationale acquise principalement aux Etats-Unis, peu de cas similaires existant en France. Enfin, il propose des recommandations sur les modalites d’evaluation du besoin et de la reponse de compensation des atteintes aux zones humides, en insistant notamment sur l’utilite d’y integrer le facteur temporel, le risque d’echec, l’ecologie du paysage et la valeur patrimoniale de ces milieux. En conclusion, l’attention est portee sur les questions que soulevent la disponibilite et l’usage des terres de compensation, l’incertitude associee aux methodes de genie ecologique et la difficulte de prevoir les trajectoires de ces ecosystemes restaures/recrees.

Buffer zones such as ponds and ditches are used to reduce field-scale losses of pesticides from subsurface drainage waters to surface waters. The objective of this study was to assess the efficiency of these buffer zones, in particular constructed wetlands, focusing specifically on sorption processes. We modelled the sorption processes of three herbicides [2-methyl-4-chlorophenoxyacetic acid (2,4-MCPA), isoproturon and napropamide] and three fungicides (boscalid, prochloraz and tebuconazole) on four substrates (two soils, sediment and straw) commonly found in a pond and ditch in Lorraine (France). A wide range of Freundlich coefficient (K fads) values was obtained, from 0.74 to 442.63 mg1 − n  L n  kg−1, and the corresponding K foc values ranged from 56 to 3,725 mg1 − n  L n  kg−1. Based on potential retention, the substrates may be classified as straw >> sediments > soils. These results show the importance of organic carbon content and nature in the process of sorption. Similarly, the studied pesticides could be classified according to their adsorption capacity as follows: prochloraz >> tebuconazole–boscalid > napropamide >> MCPA–isoproturon. This classification is strongly influenced by the physico-chemical properties of pesticides, especially solubility and K oc. Straw exhibited the largest quantity of non-desorbable pesticide residues, from 12.1 to 224.2 mg/L for all pesticides. The presence of plants could increase soil–sediment sorption capacity. Thus, establishment and maintenance of plants and straw filters should be promoted to optimise sorption processes and the efficiency of ponds and ditches in reducing surface water pollution.

The cultivation of miscanthus, a new agricultural crop used in the production of energy and biomaterial, is a potential competitor for agricultural land use. Modelling approaches are therefore needed to predict the spatial patterns of changing land use throughout a territory. Given the lack of information about how crop location is determined within the territory, a detailed understanding of farmers' choices is a prerequisite for the construction of such models. This paper presents the results of a study involving ten farmers; it shows the complexity of their decision-making processes and the diversity of practices in crop location.

Résumé L’insertion territoriale du miscanthus, nouvelle culture agricole utilisée pour la production d’énergie et de biomatériaux, peut présenter un risque de concurrence d’usage des sols. La modélisation de sa distribution spatiale est donc nécessaire pour anticiper les réorganisations du territoire. Compte tenu du manque de connaissances sur les facteurs déterminant sa localisation dans le territoire, une compréhension fine du choix des agriculteurs est un préalable nécessaire pour construire les modèles. Nous présentons les résultats d’une étude menée sur 10 agriculteurs qui montre la complexité de leur processus de décision et la diversité de pratiques de localisation du miscanthus.

La mise en évidence de l’interdépendance de certaines activités économiques vis-à-vis des services écologiques fournis par le bon état des milieux aquatiques a conduit à passer d’une gestion individualisée (où l’usager agit en fonction de ses propres objectifs et intérêts) à une gestion collective de la ressource en eau visant à la recherche d’un bénéfice global à travers la mise en œuvre de montages institutionnels concernant le maintien (ou la fourniture) d’un ou de plusieurs services écologiques. Le recours à des mécanismes de marché, comme le paiement pour services environnementaux (PSE), participe d’un enjeu visant à encourager des choix qui non seulement intègrent la valeur économique des services écologiques (ou le coût de leur perte), mais conduisent aussi à des formes de gouvernance adaptées aux enjeux environnementaux propres à chaque territoire concerné. Le PSE constitue un instrument financier d’incitation à un changement de comportement ou de pratique de la part de celui ou de ceux qui sont à l’origine de la dégradation environnementale. En France, une première expérience de PSE conduite par la Société des eaux minérales Vittel a permis de mettre en évidence les besoins et risques attachés à la mise en œuvre d’un tel mécanisme.

Nitrogen contamination of ground and surface water in the Seine, Somme and Scheldt watersheds, as well as in the receiving coastal marine zones, results in severe ecological problems. Previous modelling results showed that the implementation of classical management measures involving improvement of wastewater purification and "good agricultural practices" are not sufficient to obviate these problems. A more radical scenario was therefore established, consisting of a generalised shift to organic agriculture of all agricultural areas in the three basins, with the additional constraints that livestock is fed only on local fodder production. This scenario involves an increased livestock density in the Seine and Somme and a decrease in livestock in the Scheldt basin. It leads to a significant reduction of agricultural production that finally brings the three basins closer to autotrophy/heterotrophy equilibrium. Nitrate concentrations in most of the drainage network would drop below the threshold of 2.25 mgN/l in the most optimistic hypothesis. The excess of nitrogen over silica (with respect to the requirements of marine diatoms) delivered into the coastal zones would be decreased by a factor from 2 to 5, thus strongly reducing, but not entirely eliminating the potential for marine eutrophication.

Au regard des objectifs de développement de l’agriculture biologique (AB) affichés au niveau français, l’élevage est potentiellement un contributeur important. Le modèle de polyculture-élevage est un des fondamentaux de l’AB et a fait la preuve de sa robustesse. Mais aujourd’hui, on constate une diversité d’intégrations de l’élevage dans des unités de production, et des exigences nouvelles s’imposent à l’AB en termes de performances, du fait d’évolutions réglementaires ou de la situation des marchés. Quatre thématiques de recherche sont jugées prioritaires : i) concevoir des systèmes d’élevage plus autonomes et économes en intrants, en combinant expérimentations et suivis en ferme ; ii) évaluer l’état sanitaire des troupeaux et les outils thérapeutiques alternatifs, conformément aux attendus réglemen- taires en termes de santé et de bien-être des animaux ; iii) améliorer la maîtrise des qualités nutritionnelles, sensorielles et sanitaires des produits animaux ; iv) renforcer les interactions entre élevage biologique et environnement, en privilégiant ses impacts sur la biodiversité et sur les émissions de gaz à effet de serre, ainsi que les consommations énergétiques et les transferts de fertilité dans ou entre les unités de production. Les enseignements méthodologiques de projets de recherche sont précisés dans une dernière partie, en distinguant évaluation des performances et contributions au développement de l’AB.

The upper part of the Moselle river basin, northeastern France, shows contrasting lithology and topography: granitic formations upstream in the Vosges mountains and carbonate platform downstream on the Lorraine plateau. We measured concentration and isotopic composition of dissolved SO4 in the Moselle river and its main tributaries in order to identify the sources of sulfate. Rainwater, lichens, S-fertilizers and natural gypsum were also analyzed as potential sulfate sources. Along the Moselle river, dissolved SO4 concentrations and S–O isotopes display relationships which suggest two major sources of sulfates: 1) a low concentration and low delta values (δ34S of 6–9‰ and δ18O of 6–9‰) component upstream and 2) a high concentration and high delta values (δ34S of up to 17‰ and δ18O of up to 13‰). These are likely 1) atmospheric S input with some retention time in forest soils as carbon-bonded sulfur and 2) sulfates from the dissolution of evaporites from the Muschelkalk and Keuper formations of the Lorraine plateau.The Madon tributary drains a basin largely used for agriculture (>35% of the land surface) and formed by carbonate and evaporite rocks. Deviation from the general δ34S–δ18O trend for dissolved SO4 was found to be seasonal and related to land use and agricultural practices and are interpreted as a significant input of sulfates from fertilizers used in the area. Isotope mixing models indicate that between 1.1⁎107 and 1.9⁎107 mol of anthropogenic SO4 are annually exported through the Madon river. These values compared well with the expected annual fertilizer spreading rates in the area and demonstrate the powerful source tracing done by using S isotopes in dissolved sulfates. This implies that combining isotopic “fingerprinting" approach to knowledge of the catchment (i.e. land use, agricultural practices, river flow) would provide key information for decision makers in the context of river basin management.

Two sheep flocks were managed organically (for two years from conversion onwards) under different lambing strategies (1 lambing/year vs. 3 lambings every two years). The second system was tested as there was a producer’s interest in high productivity that is a guarantee of good economic results in conventional. Reproduction, feeding, lamb production, carcass quality, health (particularly internal parasitism), economic return of the flock, grass production, and pasture biodiversity were evaluated. The lambs were bred under low therapeutic input. The economical advantage of increasing lambing frequency was not demonstrated, whereas this strategy complexified management and resulted in higher internal parasitic infection of the lambs, and finally showed a lower stability. There were difficulties in establishing a very high feed self-sufficiency in both systems, especially the more intensive system (4 points lower), due to harsh climatic conditions; following this five-year experiment, we are changing our strategy to provide nitrogen in the systems.