The research conducted in 2002-2008 at the Institute of Herbology and Cultivation Techniques IUNG – PIB in Wrocław, in the western region of Poland (51°07’ N; 17°02’ E), assessed the effect of the cropping system on species diversity in field weed communities of maize grown in the crop rotation and in the monoculture. Changes in weed infestation were evaluated on the basis of phytosociological records taken in two systems of soil tillage – traditional (ploughing plus cultivating measures) and non-ploughing – consisting of tillage with a cultivator and seedbed preparing with a combination tillage tools. After two phases of the crop rotation, the highest biodiversity of field flora was reported in maize grown according to the conventional method, with the use of ploughing, while the lowest weed infestation level occurred in monoculture with the use of reduced system. Both in growing in the crop rotation and monoculture, after introduction of reductions in cultivation there was observed the occurrence of perennial species of Elymus repens, Cirsium arvense and Equisetum arvense, as well as an increased amount of Artemisia vulgaris.

13-23