In the years 2000 - 2010 (11 years) was conducted weed survey on the farms in conventional farming system. The aim was to detected the most harmful weeds, as important biotic, environmental stress factor, on the farms in the canopies of forage crops (alfalfa, clover) in maize, sugar beet and potato production region of the Slovak Republic. The actual weed infestation was evaluated by standard methods common used by a counting method per square. The four randomly established sample quadrants were situated minimally 20 m from field margin and apart each other, respectively. In the forage crops  23 weed species were detected, the most problematic were: perennial weed Cirsium arvense (L.) Scop., Elytrigia repens (L.)DESV, Taraxacum officinale Web. and annual weeds Chenopodium spp., Capsella bursa pastoris (L.) Med., Thlaspi arvense L., Plantago spp., Polygonum spp., Veronica spp. and Datura stramonium L.. Temporal dynamic of actual weed infestation depends on production region. In the last decade was detected the decrease of Rumex spp. in all production region. On the other side were Polygonum spp., Veronica spp. and Chenopodium spp. which increased their populations in the forage stands. The originality of result is in mapping the weed species in cultural crops.

temporal dynamics, actual weed infestation, mapping, forage crop, alfalfa

Presentation: oral