Zmiany w zbiorowiskach chwastów segetalnych wybranych roślin uprawnych na przestrzeni ostatnich 50 lat oraz prognozy na przyszłość

Abstract

Permanent human pressure on agricultural fields is a factor shaping and modifying the composition and structure of segetal commu¬nities. On arable fields, especially large-area ones, the phenomenon of impoverishment of species composition and the formation of fragmentary communities with a small number of species is observed. Communities appropriate for a given type of soil or crops are disappearing. In the communities, the total number of species is decreasing, but the number of troublesome species is increasing, which causes an increase in weed infestation of the stands. Weeds with wide adaptability, including ruderal species, which are starting to ap¬pear more and more often on agricultural fields, are becoming a problem. In recent years, an increase in the intensity of thermophilic species has also been observed. Among them, new taxa appear so far in southern Europe, such as common velvetleaf (Abutilon theo¬phrasti Medik.) or common ragweed (Ambrosia artemisiifolia L.). In the near future, we should expect problems from species that pose a significant threat to our southern neighbors, such as the Aleppo grass [Sorgum halepense (L.) Pers.], hairy cupgrass [Eriochloa villosa (Thunb.) Kunth.] or narrow-leaved ragwort (Senecio inequidens DC).