Apparent N Balance in Organic and Conventional Low Input Cropping Systems

The determination of nutrient surplus is one of the indicators of potential N losses from the agricultural system to the environment. An experiment was started in 1998 in Central Italy to evaluate the soil surface N balance of an organic and a conventional low input cropping system over a long term crop rotation. Results at the end of a 6-year crop rotation showed an estimated N surplus in organic system 1.3-2 times higher than in conventional system while N content in the top soil was not different in the two systems, so that organic system should have involved a higher N loss from that soil layer