The segetal vegetation of vineyards and crop fields of Friuli-Venezia Giulia (NE Italy) was studied. 165 phytosociological relevés were analyzed by numerical classification and compared with those of Central European isoecic coenoses. Four associations were detected: the coenoses of vineyards and of weeded summer cultures of the plain and the hill belts, corresponding to those already described from Central Europe (Geranio rotundifolii-Allietum vinealis R. Tx. ex von Rochow 1966 and Echinochloo-Setarietum pumilae Felföldy 1942 corr. Mucina
1993, respectively), and the coenoses of weeded cultures of the mountain belt and of winter crop fields, described as new associations (Galeopsido tetrahit-Galinsogetum ass. nova and Papaveretum apuli ass. nova, respectively). A new subassociation of the Echinochloo-Setarietum pumilae is proposed, and the ecological concept of agroform is introduced. The results of this study indicate that the standardization of agronomic techniques has drastically reduced the biodiversity of these associations.
