Effect of soil tillage systems and straw management on weeds in cereal stands

Ab s t r a c t. The experimental crop rotation was as follows: each crop was cultivated using two differ-ent variants of tillage, i.e. conventional tillage (CT) and minimum tillage (MT). Straw remaining on plots after the harvest of all crops was chopped and treated with four different fertilisers. In the first variant, the preparation Beta-liq was applied at the dose of 1 t ha-1 (A), in the second one, the dose of liquid fertiliser DAM 390 was 100 kg ha-1 (B), and in the third one the preparation Unifert was applied at the dose of 230 kg ha-1 (C). The fourth variant (D) was control, i.e. without fertilisers. In all experimental variants, the total dose of nitrogen was 30 kg ha-1. The Canonical Correspondence Analysis (CCA) revealed that in stands of spring barley with conventional tillage and application of Unifert (CT, C) numbers of the following weed species were increased: Fallopia convolvulus and Silene noctiflora. In the variant with Unifert (C) and in control (D) increased number of Amaranthus sp and Galium aparine plants were found, while Chenopodium album was more frequent in the variant with Beta-liq (A). Basing on results of CCA it is obvious that in winter wheat stands Cirsium arvense, Galium aparine and Lactuca serriola occurred above all in the variants with mini-mum tillage (MT) and with Unifert (C), and also in the control variant (D). Weed species Consolida orien-talis, Fallopia convolvulus, Silene noctiflora, and Veronica agrestis were more frequent in CT and A vari-ants, while in variant B increased numbers of Chenopodium album and Veronica polita were found. K e y wo r d s: weeds, straw management, soil tillage systems