Tall fescue (Festuca arundinacea Schreb) is a perennial forage crop which can be used for grazing, or as hay, silage and a component in combination with leguminous crops. When seed production is considered, a special attention ought to be paid to weed control in the founding year. Grassy weeds represent a particular problem for spring tall fescue crops, because it is not recommendable to prevent weeds during the spring sowing. This study was aimed to identify weed species and number during the founding year of tall fescue crop. For that reason, a field trial was set at the experimental field of the Institute of Forage Crops in Kruševac, during 2007. The investigated cultivar of tall fescue was K-20. The applied herbicides in the trial were the following: Lentemul (2,4 D), Banvel (dicamba), Galbenon (bentazon) and Boss (clopyralid). The trial was set in random complete block design with four replications. Number of weed species was determined per square meter and herbicide efficiency degree was established according to Dodel. Results obtained in this study showed that in tall fescue crop were observed twenty weed species, as annual as perennial ones, with their average total number of 21.2 individuals/m 2 . Annual weed species were most abundant (13 individuals/m 2 ). The highest frequency of appearance showed Matricaria chamomilla (3.63 individuals//m 2 ), Cirsium arvense (3.52 individuals//m 2 ) and Chenopodium album (2.60 individuals/m 2 ). The greatest coefficient of efficiency (83.62) was reached by the herbicide Boss, and the lowest one (64.46) by the herbicide Lentemul. The best prevention effect on annual weed species was shown by the herbicide Boss (86.6), but the herbicide Banvel was the best in preventing perennial weeds (92.6). However, in order to reach higher forage yields and better forage quality, it is necessary to kill weeds in the year of tall fescue crop founding, and also during further exploitation of tall fescue crop. Results of this study point to a necessity of chemical protection measures for an efficient weed control in tall fescue crop.

tall fescue, weeds, herbicides, coefficient of efficiency

Presentation: oral