A method is proposed for the evaluation of potential impacts of arable farming systems on the environment. The first step is the calculation of evaluation modules that estimate the impact of each agricultural technique on each environmental component. These modules are aggregated either to rank or classify cropping systems by means of multicriteria methods or to generate an agro-ecological indicator (AEI). Nine agro-ecological indicators have been tested: nitrogen fertilisation, phosphorus fertilisation, pesticides, irrigation, crop succession, cropping pattern,crop covering, organic matter, and ecological structures; two others are in development: energy and soil management. Together, the AEIs provide a 'control panel' for the farm. These agro-ecological indicators are calculated mostly at the field level and then averaged over the whole farm. As input, few parameters used in the calculation of these indicators are region-specific (e.g., reference of sowing dates, leaching periods). Since 1994, the indicators are established with data from a network of 17 arable farms in the Rhine plain (France and Germany) to characterise the degree to which the objectives of sustainable agriculture have been reached by these farms. (C) 2000 Elsevier Science Inc. All rights reserved.
