Effect of different defoliation practices on weeds in an upland meadow

The effect of different defoliation management on the occurrence of weed species was studied in upland meadow in the Jizerske Mountains from 2000 to 2007. The following treatments were applied: cutting twice a year with biomass removal, mulching from 1 to 3 times a year and no management. The semi-natural grassland had been occasionally grazed or cut before the start of the experiment. During the experiment, tall dicotyledonous species such as Anthriscus sylvestris, Cirsium arvense and Urtica dioica as well as the grass weed Elytrigia repens were promoted by no management and mulching once a year. On the other hand, prostrate species, namely Taraxacum spp., responded positively to a higher frequency of defoliation and disappeared under no management. Aegopodium podagraria spread in plots mulched twice or three times a year. Plant species number increased in treatments consisting of cutting twice and mulching twice or three times; it decreased where no management was applied. Mulching performed at least twice a year is suitable for non-chemical restriction of undesirable weeds such as Cirsium arvense, Urtica dioica or Elytrigia repens, but supports an increase of Aegopodium podagraria.