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Résumé :
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A multi-criteria evaluation was carried out to evaluae the agro-environmental sustainability of the two low input diry faming systems, permanent measows system (SH) and mixed crops-meadows system (SPCE), of the experimental farm of INRA-Mirecourt. Twelve environmental indicators from differents methods (INDIGO, Peigné 2003, PLANETE) were calculated in order to evaluate the impact on abiotic resources : nitrate leaching, phosphorus losses, pesticides loss in surface and groundwater, pesticides loss in the air, ammonia volatilization, nitrous oxide, methane and carbon dioxide emission soil organic matter content, phophorus availability and non-renewable energy use. Indicator results were ranked on a scale from 0 to 10, where 7 is the tolerance value. Indicators were aggregated into four main criteria (water and air pollution risk, soil quality and energy consumption), weighted and attributes a qualitative ranking scale with the tool DEXI. Data were collected at plot and farme scale for the period 2007-2008. The first results of this evaluation showed that SH has a "very high" ans SPCE a "medium to high" agro-environmental sustainability. The impact on abiotic resources is "very low" for SH and "medium to low" for SPCE. However both systems had a medium to low impact on water pollution, soil quality and energy consumption. Air pollution obrained the worst result "medium to bad"impact), due to high emission for both systems. In fact the indicators of nitrous oxide, methane ande carbon dioxide emmission obrained respectively a score of 5.8, 2.9 and 7.5 for SH, and 6.8, 4.2 and 6.4 for SPCE These results correspond to an emission amount of 2 kg N20/ha, 105.7 kg CH4/ha and 0.2 t CO2/ha for SH, and 1.6 kg N20/ha, 74.1kgCH4/ha and 0.3 t CO2/ha for SPCE. These results underling the role of dairy farming on global GHG emission, especially of methane emission from enteric fermentation. All other indicators yielded a score above the tolerance value, excepted nitrate leaching (6.9) and ammonia volatilization (6.9) for SPCE. Further work should be carried out in order to validate the proposed indicators and aggregation.
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