Geographical downscaling of outputs provided by an economic farm model calibrated at the regional level

International audienceThere is a strong need for accurate and spatially referenced information regarding policy making and model linkage. This need has been expressed by land users, and policy and decision makers in order to estimate both spatially and locally the impacts of European policy (like the Common Agricultural Policy) and/or global changes on farm-groups. These entities are defined according to variables such as altitude, economic size and type of farming (referring to land uses). European farm-groups are provided through the Farm Accountancy Data Network (FADN) as statistical information delivered at regional level. The aim of the study is to map locally farm-group probabilities within each region. The mapping of the farm-groups is done in two steps: (1) by mapping locally the co-variables associated to the farm-groups, i.e. altitude and land uses; (2) by using regional FADN data as a priori knowledge for transforming land uses and altitude information into farm-groups location probabilities within each region. The downscaling process focuses on the land use mapping since land use data are originally point information located every 18 km. Interpolation of land use data is done at 100 m by using co-variables like land cover, altitude, climate and soil data which are continuous layers usually provided at fine resolution. Once the farm-groups are mapped, European Policy and global changes scenarios are run through an agro-economic model for assessing environmental impacts locally

Les valorisations énergétiques des biomasses, difficultés et promesses

[eng] Energetic valorization of biomass . Energetic uses of biomass are growing very slowly. To day, in 1983, about 3,5 on 4 Millions of tons (oil equivalent) of wood and by products from wood processing industries are valorized as solid fuels. Energetic supply of others by-products like ce real -straws, animal wastes, energetic crops are not yet significant. Monetary costs, for final user, are usually important, especially when the biomass needs to be collected. Biomass transportation amplifies the costs of energy because it generates différents rents among biomass producers. It's why on farm or on firm biomass uses often are the better economic ways. . Two hypothesis for biomass development may be suggested : . First, a low scenario; in this case, dry biomass only, wood and straw, should be burned to satisfy thermic needs, directly on production sites or after a transportation on short distances. . Secondly a high scenario which supposes technical improvements and an increase of the oil prices so that liquid fuels conversion for biomass should become realistic. . In the best conditions, the whole energetic supply should not probably exceed 5 or 6 Mtoe at the end of the century. Clearly this estimation is farm from official ones presuming very strong incentives and situated about 8 or 10 Mtoe in 1990. [fre] L'utilisation énergétique de la biomasse progresse très lentement. 3,5 à 4 Mtep de bois et de sous-produits de l'exploitation forestière sont actuellement valorisées comme combustibles. La contribution énergétique des autres sous-produits, pailles, déjections animales, cultures énergétiques est encore négligeable. Le coût de l'énergie finale, rendue utilisateur, est généralement important, surtout si les biomasses sont collectées. La collecte amplifie les coûts en faisant naître des rentes. C'est pourquoi l'utilisation sur place des biomasses est souvent préférable. . Deux hypothèses de développement sont proposées : un scénario bas où seules les biomasses sèches, essentiellement des sous-produits comme les bois et la paille, seront exploitées à des fins thermiques, surtout sur les lieux mêmes de production. Un scénario haut, supposant une hausse du prix du pétrole, où les enjeux concerneraient la production de carburants: méthanol, acétone butanol, éthanol. . Dans le meilleur des cas, la contribution totale énergétique ne devrait pasdépasser 5 à 6 Mtep vers la fin des années 90. Celle-ci est assez nettement en retrait par rapport aux évaluations officielles qui se situent autour de 8 à 10 Mtep dès 1990, dans une perspective plus volontariste.

Use of available information at a European level to construct crop nitrogen response curves for the regions of the EU

Nowadays European agriculture is evolving in a context where policy-making and environmental concerns play a key role. To better assess agro-environmental policies, the AROPAj agricultural supply model needs to take into account the technical characteristics of crop management for different farms. A method to build up specific relationships between yield and nitrogen fertilization that takes into account agronomic techniques is proposed in this paper. The nitrogen response curve is based on an exponential function that integrates economic properties consistently from an agronomic point of view. In AROPAj, individual production systems (farm types) do not have a given location within a specified region and in databases technical information is scarce. The method involves determining technical and physical characteristics, inputs that allow the STICS crop model to assess the yield response to nitrogen of each crop on every farm type. From this information, a nitrogen response curve can be drawn up for each crop of each one of the farms. It can take into account both nitrogen from purchased fertilizer and nitrogen from animal effluents produced on farm. The method was designed to be adaptable to any European region, and tests carried out on two French regions covering a wide range of situations (crops, soils, climates and techniques) showed it was able to cope with varying prices and environments. The agronomic consistency of STICS inputs and curve shapes was also checked. When incorporated into the AROPAj economic model, the response curves can be used to render farms more sensitive to agricultural policy scenarios, by allowing their optimal fertilization level to be adjusted.

Contribution a la lutte contre l'effet de serre Stocker du carbone dans les sols agricoles de France ?

Expertise scientifique collective - Rapport d'expertise realise par l'INRA a la demande du Ministere de l'Ecologie et du Developpement DurableSIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : RP 16445 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Les progrès de la modélisation intégrée

L'objectif d'une modélisation intégrée est de traiter les problématiques concernant la ressource en eau (en termes de quantité et de qualité) en combinant les différentes disciplines la caractérisant : météorologie, hydrologie, agronomie, biogéochimie, économie. En effet, la ressource en eau est affectée par l’anthropisation, qu’il s’agisse des modifications de l'occupation du sol et/ou les aménagements hydrologiques, ou des activités générant des pollutions ponctuelles ou diffuses qui vont être transférées dans l'hydrosystème en fonction en particulier des caractéristiques météorologiques. Les polluants sont sujet à des processus biogéochimiques qui les conduisent à se transformer en divers sous produits. Ainsi, les différents éléments de l'hydrosystème interagissent les uns avec les autres (Figure 1), ce qui incite les chercheurs à bâtir une modélisation plus intégrée de l'hydrosystème