EN
As a result of studied carried out in meliorated Kosarzewka river valley, 10 plant communities in phytosociological classes were distinguishcd: Phragmitetea (2 complex), Molinio-Arrhenatheretea of Molinietalia order (4 complex), of Arrhenatheretalia order (2 complex and 1 community), and Festuco-Brometea (1 complex). The largest area (about 90%) was covered by 3 communities of Molinio-Arrhenatheretea class of Arrhenatheretalia order, in which Alopecuretum pratensis yielded the best (7.4 t ha⁻¹) similarly as Arrhenatheretum medioeuropaeum complex (6.4 t ha⁻¹) and community with Poa pratensis + Festuca rubra (6.7 t ha⁻¹). Total hay yields from every communities selected in valley studied were defined as medium (6.7 t ha⁻¹). Communities contained 111 plant species.