Occurence of common wild oat (Avena fatua L.) on cultivated fields in north-eastern Poland

The paper analyses the spatial distribution of common wild oat (Avena fatua L.) on cultivated fields in the Olsztyn and Suwałki Districts. Data are presented on the occurrence of this species in 1908-1909, based on works of a German scientist Z a d e (1912), and the present author's own data for two periods: 1966-1975 and 1976-1982. Analysis of the data points to the invasive character of Auena fatua in north-eastern Poland in the period 1976-1982. At present, the distribution of common wild oat is very similar to that at the beginning of the 20 century (1908-1909). In the area under study common wild oat (Avena fatua L.) seems to be most dangerous for spring cereals cultivated upon soils of good wheat complex. The data confirm suggestions by many authors that common wild oat belongs to calciphilous species