Repeated surveys in Finland follow the changes of weed flora in spring cereal fields

Summary in the original language of the document

Typically, as observed in 1997-1999, the average weed species number was about 25 in organically farmed field and some 10 species less in conventionally farmed field. In this respect, organic farming clearly promotes biodiversity at the farm scale but not so much at the national scale as the field area of organic cropping is only about 6 % of the total Finnish field area.