Physiological processes of plants can be modified by organic compounds called growth regulators. The aim of this study was to evaluate the effectiveness of selected growth regulators: Moddus 250 EC, Bercema CCC and Flordimex 420 SL on the compactness of mixed lawn turfs, where the modifying element was the percentage of perennial ryegrass (Lolium perenne L.) of the Inka cultivar. The study was conducted on the experimental plots of the University of Natural Sciences and Humanities in Siedlce (52°10’ N; 22°17’ E) in 2003-2005. Application of growth regulators had a significant effect on the compactness of the tested lawn grass mixtures. The upward tendency was visible in the case of application of Bercema CCC. This growth regulator had the highest beneficial effect in the case of mixtures with 20% and 40% proportion of perennial ryegrass. The lowest degree of lawn compactness was observed for the mixture with 20% of perennial ryegrass after application of Flordimex. The interaction between percentage proportion of perennial ryegrass in mixtures and applied growth regulators had a significant influence on degree of grass compactness of the studied lawn grass mixtures.

101-109