A participative network of organic and conventional crop farms in the Seine Basin (France) for evaluating nitrate leaching and yield performance

In the Seine Basin, characterized by intensive arable crops, most surface and groundwater is contaminated by nitrate (NO3−). A collaborative study was set up, involving a network of volunteer farmers, to investigate NO3− leaching with ceramic cups (90cm deep) on whole crop rotations of organic (OF) and conventional (CF) commercial farms in the Seine Basin. A total of eight CF and six OF systems were studied (63 fields) in five different soil and climate conditions, taking into account a wide diversity of practices (including low or no exogenous N inputs, systematic catch-crop implementation, and no tillage) and use of different exogenous organic matter (EOM) such as biogas residue; slurry; poultry manure; and cow and horse manure.