EFFECT OF GROWTH REGULATORS ON COMPACTNESS OF LAWN TURFS WITH VARIOUS PROPORTION OF PERENNIAL RYEGRASS

Acta Sci. Pol., Agricultura 10(3) 2011, 101-109 EFFECT OF GROWTH REGULATORS ON COMPACTNESS OF LAWN TURFS WITH VARIOUS PROPORTION OF PERENNIAL RYEGRASS Krzysztof Starczewski, Agnieszka Affek-Starczewska Siedlce University of Natural Sciences and Humanities 1 Abstract. 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. Key words: 2-chloroektyl trimethylamine chloride, etefon, Inka, lawn compactness, lawn grasses, Lolium perenne, trinexapac-ethyl INTRODUCTION Plant physiological processes can be modified by growth regulators. According to Jankiewicz [1997] the effects of using growth regulators are among others: hindering the elongation of cells in stalks (at higher concentrations also a reduction in cell divisions in the apical meristem occurs), thickening of the stalk, a delay of plant ageing, increased content of proteins, chlorophyll and mineral elements in the above-ground part. Growth regulators also participate in stimulating formation of generative organs [Jankiewicz 1997]. Experiments involving the application of dense sowing of retardants showed an increase in the total number of shoots [Szmigiel 1997]. Results of the Corresponding author Adres do korespondencji: dr inż. Krzysztof Starczewski, Department of Grassland Management and Shaping Green Areas of Siedlce University of Natural Sciences and Humanities, B. Prusa 14, 08-110 Siedlce, e-mail: kstarczewski@uph.edu.pl

102 K. Starczewski, A. Affek-Starczewska greenhouse experiments over the effect of trinexapac-ethyl on growth of lawn grasses indicate its effectiveness in limiting grass growth [Fagerness i Penner 1998]. The application of this compound had also an effect on an increase in tolerance to overshadowing of the grass Zoysia matrella L. parallel to the shortening of stalks by 73- -76% [Qian and Enegelke 1999]. Encouraging results of pot experiments by American authors induced to conduct field studies under Polish conditions. In the zone of temperate climate perennial ryegrass (Lolium perenne L.) is one of the species most often used for establishing lawns. Lawn cultivars of this species develop quickly after sowing, increase the turf density and are relatively resistant to treading [Domański and Golińska 2003]. Other desirable features of perennial ryegrass are: tolerance to lower cutting and smaller requirements concerning nitrogen fertilization [Broda et al. 2003]. In comparison with other lawn grasses, perennial ryegrass is characterized by the most balanced but low values of turf compactness throughout the growing period [Harkot and Czarnecki 1999]. This is a feature which can have an effect on limitations on the use of this species in lawn mixtures. This grass obtains good values of turf compactness in the case of frequent cutting (10-25 times in the growing period) [Jankowski et al. 1999, Czarnecki and Harkot 2002]. On the basis of results of the study carried out in cereal crops, satisfying values of turf compactness could be expected after the use of growth regulators on lawn turfs with a proportion of perennial ryegrass. Therefore, the aim of this study was to estimate the effect of selected growth regulators on the turf compactness of lawn turfs. MATERIAL AND METHODS The study was carried out in 2003-2005 on an experimental plots of the University of Natural Sciences and Humanities in Siedlce (52 10 N; 22 17 E), in the form of a field experiment established in the split-block design, in four replications. The experimental unit was a plot with an area of 1 m 2. Four lawn mixtures were observed, where the modifying element was the percentage of perennial ryegrass (Lolium perenne L.) of the cultivar Inka (Table 1). The experiment was established in May 2002 roku. From 2003 the following growth regulators were applied every year: Moddus 250 EC at the concentration 2% (the active substance: trinexapac-ethyl), Bercema CCC at the concentration 30% (the active substance: 2-chloroektyl trimethylamine chloride) and Flordimex 420 SL at the concentration 30% (the active substance: etefon (2-chloroethyl phosphoric acid) as spraying in the spring (May) and summer (August) periods, according to the recommendations of producers in an amount of 30 cm 3 m -2 of spray liquid. Supplementing essential nutrients for grasses used in the experiment was provided by a single application at the beginning of each growing season of the slow-release granulated mineral fertilizer Sierrablen in pellets from natural resin (Osmocote technology) (N 28%, P 5%, K 5%, Fe 0,5%) at a rate of 40 g m -1. The lawns were cut every 7-10 days at a height of 6cm. The time of cutting was dependent on the rate of plant regrowth, and here 12 cm was the critical height. In the course of the experiment (2003-2005), the turf compactness of grasses was assessed each year. The method by IHAR was accepted for the assessment [Prończuk 1993]. The 9-point quality scale was applied, according to which the value 1 meant bad turf compactness (lack of plants) 0%, 3 poor compactness (plants are at large Acta Sci. Pol.

Compactness of turf... 103 intervals) 20%, 5 sufficient compactness 60%, 7 good compactness (small patches of soil) 80%, 9 very good compactness (ideal carpet) 100% covering of the soil surface. This assessment was performed once a month (between 15-20 of each month) during the whole growing period, that is from May to October inclusive, by one person in the morning hours (9-11), at the sunny weather. Owing to the location of the tested area in the region without trees and buildings, the effect of overshadowing was not taken into account. The obtained results of the study were analysed statistically using the analysis of variance, and the means were compared with Tukey's test. Table 1. Composition of tested lawn mixtures (own project) Tabela 1. Skład materiału siewnego mieszanek trawnikowych (projekt własny) Mixture code Nazwa mieszanki M1 M2 M3 M4 Species Gatunek Cultivar Odmiana Share of weight Udział wagowy % życica trwała perennial ryegrass (Lolium perenne L.) Inka 20 kostrzewa czerwona red fescue (Festuca rubra L.) Adio 20 kostrzewa owcza sheep s fescue (Festuca ovina L.) Noni 20 kostrzewa różnolistna variousleaf fescue Sawa (Festuca heterophylla Lam.) 20 mietlica pospolita fine bent grass (Agrostis tenuis L.) Niwa 20 życica trwała perennial ryegrass (Lolium perenne L.) Inka 40 kostrzewa czerwona red fescue (Festuca rubra L.) Adio 15 kostrzewa owcza sheep s fescue (Festuca ovina L.) Noni 15 kostrzewa różnolistna variousleaf fescue Sawa (Festuca heterophylla Lam.) 15 mietlica pospolita fine bent grass (Agrostis tenuis L.) Niwa 15 życica trwała perennal ryegrass (Lolium perenne L.) Inka 60 kostrzewa czerwona red fescue (Festuca rubra L.) Adio 10 kostrzewa owcza sheep s fescue (Festuca ovina L.) Noni 10 kostrzewa różnolistna variousleaf fescue Sawa (Festuca heterophylla Lam.) 10 mietlica pospolita fine bent grass (Agrostis tenuis L.) Niwa 10 życica trwała perennial ryegrass (Lolium perenne L.) Inka 80 kostrzewa czerwona red fescue (Festuca rubra L.) Adio 5 kostrzewa owcza sheep s fescue (Festuca ovina L.) Noni 5 kostrzewa różnolistna variousleaf fescue Sawa (Festuca heterophylla Lam.) 5 mietlica pospolita fine bent grass (Agrostis tenuis L.) Niwa 5 The lawn experiments were carried out in soil classified according to the classification by Dobrzański and Zawadzki [1995] as the division of anthropogenic soils, the order of culture earth soils, the type of hortisols, formed from slightly loamy sand. The soil on which the experiment was established had alkaline reaction both in the solution of KCl and in H 2 O (Table 2). The soil was characterized by a very high content of phosphorus and magnesium, and a low content of potassium. Moreover, a relatively high abundance of copper and zinc and a moderate abundance of manganese was reported. Agricultura 10(3) 2011

104 K. Starczewski, A. Affek-Starczewska Table 2. Chemical properties of soil Tabela 2. Właściwości chemiczne gleby Content Zawartość % Content mg 100 g -1 DM Zawartość mg 100 g -1 s.m. Content of soil components Zawartość składników gleby mg 100 g -1 Content Zawartość mg dm -3 total N in w in w N-NO N-ogólny 3 N-NO 4 P 2O 5 K 2O Mg Ca KCl H 2O 0.29 21.13 40.80 90 5.5 11.4 2740 7.20 7.24 Content of components, mg kg -1 of soil Zawartość składników, mg kg -1 gleby Cu Zn Mn 28.7 150.7 162.0 The place where the experiment was carried out has typical conditions of the transitory climate between marine and continental climates. The annual mean air temperature ranges within 6,7-6,9 C, and in the summer period the mean daily air temperature amounts to 15 C. There are between 50 and 60 days with frost and from 110 to 138 days with ground frost. Annual precipitation is on the level 550-650 mm, and the rainfall is not frequent but heavy. The growing period starts between 1 st and 10 th of April and finishes between 20 th and 30 th October, thus it lasts 200-220 days. The time of snow cover lying ranges from 80-87 days [Kondracki 2002]. The mean temperatures from the years of the study, both annual and those in the growing season, were higher than the means from many-year period (Table 3), and total precipitations in the studied growing periods were lower than those from many-year period (Table 4). According to Kaczorowska [1962] these were conditions which allow regarding the tested years as dry. Table 3. Air temperatures in 2002-2005 in Siedlce Tabela 3. Temperatury powietrza w latach 2002-2005 w Siedlcach Mean monthly air temperature Średnia miesięczna temperatura powietrza, C month miesiąc 2002 2003 2004 2005 mean średnia 1960-2005 January Styczeń -1.7-3.7-5.6 0.7-3.5 February Luty 3.3-6.0-0.9-3.9-2.4 March Marzec 4.3 1.3 2.9-0.9 1.5 April Kwiecień 8.6 6.7 7.7 8.5 7.5 May Maj 16.7 15.3 11.5 12.9 13.3 June Czerwiec 16.9 16.9 15.2 15.4 16.2 July Lipiec 20.8 19.8 17.3 19.7 17.8 August Sierpień 20.1 18.3 18.5 16.9 17.2 September Wrzesień 12.8 13.2 13.0 14.6 12.7 October Październik 7.1 5.3 9.8 8.5 7.8 November Listopad 3.9 4.9 3.3 3.0 2.6 December Grudzień -7.4 0.8 1.5-0.8-1.5 Mean April October Średnia kwiecień październik 14.7 13.6 13.3 13.8 13.2 Annual mean Średnia roczna 8.8 7.7 7.9 7.9 7.4 ph Acta Sci. Pol.

Compactness of turf... 105 Table 4. Precipitation in Siedlce in 2002-2005 Tabela 4. Opady atmosferyczne w Siedlcach w latach 2002-2005 Total precipitation Suma opadów atmosferycznych, mm month miesiąc 2002 2003 2004 2005 mean średnia 1960-2005 January Styczeń 35.6 23.5 30.3 33.7 25.2 February Luty 58.0 10.5 43.2 37.9 22.6 March Marzec 32.1 16.4 62.6 32.5 26.4 April Kwiecień 10.8 26.1 36.4 8.9 36.1 May Maj 24.2 32.0 81.6 75.1 53.0 June Czerwiec 75.1 61.7 45.2 48.9 72.7 July Lipiec 58.6 44.5 53.5 94.1 69.6 August Sierpień 32.2 62.2 69.3 24.9 62.1 September Wrzesień 31.9 36.5 17.5 18.0 52.4 October Październik 59.2 44.0 32.2 2.0 37.7 November Listopad 32.9 25.5 46.8 23.4 38.4 December Grudzień 6.8 40.6 16.2 68.0 32.8 Mean April October Średnia kwiecień październik 292.0 307.0 335.7 271.9 383.6 Annual mean Średnia roczna 457.4 423.5 534.8 467.4 529.0 RESULTS AND DISCUSSION Turf compactness is one of the most important features determining the lawn quality. According to Prończuk [2002] this feature is of particular importance on sports and recreational lawns. According to many authors [Czarnecki and Harkot 2002, Prończuk 2002, Jankowski et al. 2003] dense and even turf compactness of the lawn has a large effect on its functional value. Their study proved that the turf quality is dependent on site conditions, the weather conditions in the growing period, that is the temperature, precipitation, the length of day, sun exposure [Prończuk and Prończuk 1994], as well on selection of species and cultivars of grasses for lawn sowing. The presented study (Tables 5-7) showed the significant effect of the weather conditions which occurred in individual years and months of the observations on the tested experimental factors. The composition of mixtures applied in the experiment had a considerable effect on lawn turf compactness. Consequently, it can be found that lawn turf compactness was dependent both on uncontrolled factors and the applied experimental factors (growth regulators, the composition of lawn mixtures). The best compactness of lawn turfs were recorded in 2003 and 2004 (Table 5). The mean of compactness for all the mixtures amounted to 7.09 and 6.82 points, respectively, whereas they were slightly worse in the last year of the study (2005) (5.96 points). Irrespective of the years of the study, the best compactness was obtained for the mixture with 80% proportion of perennial ryegrass (M4). In this case the mean of three years of the study was 6.83 points. The mixtures M1 with 20% proportion of perennial ryegrass and M2 with 40% proportion of perennial ryegrass had significantly worse turf compactness, amounting to 6.43 and 6.57 points, respectively. Agricultura 10(3) 2011

106 K. Starczewski, A. Affek-Starczewska Table 5. Lawn compactness depending on years of study and tested mixtures Tabela 5. Zadarnienie trawnika w zależności od lat badań i stosowanych mieszanek Lawn mixture Year Rok Mieszanka trawnikowa 2003 2004 2005 mean średnia M1 6.96 6.58 5.76 6.43 M2 6.88 6.81 6.03 6.57 M3 7.19 6.93 5.83 6.65 M4 7.33 6.94 6.22 6.83 Mean Średnia 7.09 6.82 5.96 6.62 LSD 0.05 NIR 0,05 for dla: years lat 0.45 mixtures mieszanek 0.23 interaction interakcji: year mixture rok mieszanka ns ni ns ni non-significant difference różnica nieistotna The growth regulators obtained (Table 6) significantly modified the turf compactness of the tested mixtures. The application of Flordimex (compactness around 70%) for all the tested mixtures turned out to be unfavourable, whereas the use of Bercema resulted in obtaining the best values for mixtures M1, M2 and M3. It is notable that in the case of mixture M4 a very good compactness was obtained on the control, whereas the applied growth regulators had a negative effect of lawn turf compactness. Table 6. Lawn turf compactness depending on growth regulators and tested mixtures Tabela 6. Zadarnienie trawnika w zależności od stosowanych regulatorów wzrostu i mieszanek Growth regulator Lawn mixture Mieszanka trawnikowa Regulator wzrostu M1 M2 M3 M4 mean średnia Control Kontrola 6.54 6.57 6.68 7.19 6.75 Moddus 6.47 6.50 6.75 6.71 6.61 Bercema 6.92 6.85 6.79 6.82 6.85 Flordimex 5.81 6.38 6.38 6.60 6.29 Mean Średnia 6.44 6.58 6.65 6.83 6.62 LSD 0.05 NIR 0,05 for dla: interaction interakcji: Growth regulator mixture regulator wzrostu mieszanka 0.45 Lawn compactness was similar in next months from May to August (Table 7), and its assessment remained in a small range of 6.34-6.45 points. Compactness improved in September (6,73 points) and October (7,45 points.), which means that the soil surface was covered in more than 80%. However, the course of weather conditions caused that in the first year of the study (2003) the best compactness was recorded in June and July, in the second year (2004) in October, and in the third year of the study (2005) from August to October (Fig. 1). Tendencies to an increase in lawn compactness in autumn was also observed by other authors [Grabowski et al. 1999, 2003, Jankowski et al. 1999]. Turf compactness in subsequent months of growth was also modified by the growth regulators applied, A certain tendency to turf compactness improvement occurred after applying Moddus and Bercema, whereas the application of Flordimex resulted in significant worsening of turf, particularly in the 3 year (2005) of the study (4.13 points). Acta Sci. Pol.

Compactness of turf... 107 Table 7. Lawn compactness depending on months, years of study and growth regulators Tabela 7. Zadarnienie trawnika w zależności od miesięcy, lat badań i stosowanych regulatorów wzrostu Growth regulator Regulator wzrostu May maj June czerwiec July lipiec Month Miesiąc August sierpień September wrzesień October październik mean średnia 2003 Control Kontrola 7.69 6.31 6.88 6.94 6.94 7.38 7.02 Moddus 7.63 6.63 7.19 7.06 6.81 7.63 7.16 Bercema 7.88 6.69 7.38 7.13 7.06 7.69 7.31 Flordimex 7.69 6.38 7.06 6.44 6.69 7.00 6.88 2004 Control Kontrola 5.88 7.19 6.81 6.44 6.56 8.25 6.86 Moddus 5.94 7.25 6.56 6.25 6.69 8.38 6.85 Bercema 6.06 7.31 6.69 6.56 6.94 8.25 6.97 Flordimex 5.94 7.13 6.50 5.00 6.75 8.25 6.60 2005 Control Kontrola 5.75 5.50 5.31 7.06 7.25 7.31 6.36 Moddus 5.69 5.50 5.31 6.50 6.00 5.94 5.82 Bercema 5.69 5.44 5.38 7.00 7.00 7.06 6.26 Flordimex 5.50 5.25 5.06 4.13 6.13 6.31 5.40 Mean Średnia 6.45 6.38 6.34 6.38 6.74 7.45 6.62 LSD 0.05 NIR 0,05 for dla: interaction interakcji: growth regulator month regulator wzrostu miesiąc 0.74 Fig. 1. Lawn compactness (points) depending on used mixtures of perennial ryegrass in each month of studied growing seasons Rys. 1. Zadarnienie trawnika (pkt.) w zależności od stosowanych mieszanek życicy trwałej w poszczególnych miesiącach badanych okresów wegetacyjnych Agricultura 10(3) 2011

108 K. Starczewski, A. Affek-Starczewska CONCLUSIONS 1. The results obtained indicated different responses of turfs to individual growth regulators. 2. The use of Bercema CCC (the active substance: 2-chloroektyl trimethylamine chloride) had a positive effect on the degree of turf compactness. This effect was clearly visible in the case of mixtures with 20% and 40% of perennial ryegrass. 3. The use of Flordimex (the active substance: etefon (2-chloroethyl phosphoric acid) significantly decreased the degree of turf compactness of mixture with 20% of perennial ryegrass. 4. A degree of lawn compactness of the tested lawn mixtures was significantly affected by interaction of percentage of perennial ryegrass in mixtures and the growth regulators applied. The best mean lawn compactness during the study was obtained for the mixture with the highest (80%) proportion of perennial ryegrass and after the application of Bercema CCC. REFERENCES Broda Z., Kozłowski S., Kaszuba J., 2003. Perspektywy hodowli Lolium perenne [Prospects for cultivation of Lolium perenne]. Łąkarstwo w Polsce 6, 29-36 [in Polish]. Czarnecki Z., Harkot W., 2002. Wpływ częstotliwości koszenia na zadarnianie powierzchni przez trawnikowe odmiany Lolium perenne [Effect of cutting frequency on surface sodding by lawn cultivars of Lollium perenne]. Łąkarstwo w Polsce 5, 43-48 [in Polish]. Dobrzański B., Zawadzki S., 1995. Gleboznawstwo [Soil science]. PWRiL Warszawa [in Polish]. Domański P.J., Golińska B., 2003. Perspektywy Lolium perenne w użytkowaniu trawnikowym i darniowym [Prospects for Lollium perenne in lawn and turf utilization]. Łąkarstwo w Polsce 6, 37-45 [in Polish]. Fagerness M.J., Penner D., 1998. Spray application parameters that influence the growth inhibiting effects of trinexapac ethyl. Crop Sci. 38, 1028-1035. Grabowski K., Grzegorczyk S., Benedycki S., Kwietniewski H., 1999. Ocena wartości użytkowej wybranych gatunków i odmian traw gazonowych do obsiewu nawierzchni trawiastych [Assessment of functional value of selected species and cultivars of lawn grasses for sowing of grass surfaces]. Fol. Univ. Agric. Stetin, Agricultura 75, 81-88 [in Polish]. Grabowski K., Grzegorczyk S., Kwietniewski H., 2003. Ocena przydatności gatunków i odmian traw gazonowych na trawniki rekreacyjne w warunkach Pojezierza Olsztyńskiego [Assessment of usefulness of species and cultivars of lawn grasses for recreational lawns in conditions of the Olsztyn Lake District]. Biul. IHAR 225, 295-302 [in Polish]. Harkot W., Czarnecki Z., 1999. Przydatność polskich odmian gazonowych do zadarniania powierzchni w trudnych warunkach glebowych [Usefulness of Polish lawn cultivars for surface sodding under difficult soil conditions]. Fol. Univ. Agric. Stetin., Agricultura 75, 117- -120 [in Polish]. Jankiewicz L.S., 1997. Retardanty i niektóre inne syntetyczne inhibitory wzrostu oraz wybrane substancje modyfikujące wzrost [Retardants and some other synthetic growth inhibitors and selected substances modifying growth]. [In:] Regulatory wzrostu i rozwoju roślin, ed. L.S. Jankiewicz, Wyd. Nauk. PWN, 108-123 [in Polish]. Jankowski K., Ciepiela G., Jodełka J., Kolczarek R., 1999. Analiza porównawcza mieszanek gazonowych uprawianych w warunkach Podlasia [Comparative analysis of lawn mixtures cultivated under conditions of Podlasie]. Fol. Univ. Agric. Stetin., Agricultura 75, 133-140 [in Polish]. Acta Sci. Pol.

Compactness of turf... 109 Jankowski K., Jodełka J., Ciepiela G., Kolczarek R., 2003. Ocena traw gazonowych w ekstensywnym użytkowaniu trawnika [Assessment of lawn grasses in extensive lawn utilization]. Biul. IHAR 225, 259-264 [in Polish]. Kaczorowska Z., 1962. Opady w Polsce w przekroju wieloletnim [Precipitation in Poland in many-year perspective]. Wydawnictwa geologiczne Warszawa [in Polish]. Kondracki J., 2002. Geografia regionalna Polski [Regional geography of Poland]. PWN Warszawa [in Polish]. Prończuk M., Prończuk S., 1994. Wstępna ocena odporności traw gazonowych na choroby w Polsce [Initial assessment of lawn grass resistance to diseases in Poland], Genet. Pol. 35A, 341-348 [in Polish]. Prończuk S., 1993. System oceny traw gazonowych [Lawn grasses evaluation system]. Biul. IHAR 186, 127-132 [in Polish]. Prończuk S., 2002. Uwarunkowania technologiczne w uprawie i ocenie trawników [Technological determinants in cultivation and assessment of lawns]. Prz. Nauk., Inżynieria i Kształtowanie Środowiska 1(24), 70-78 [in Polish]. Szmigiel A., 1997. Wpływ zagęszczonego siewu i retardantów na architekturę łanu pszenicy jarej i jęczmienia jarego [Effect of dense sowing and retardants on the canopy structure of spring wheat and spring barley]. Zesz. Nauk. AR w Krakowie, Sesja nauk. 48, 151-156 [in Polish]. Qian Y.L., Engelke M.C., 1999. Influence of Trinexapac Ethyl on Diamond Zoysiagrass in Shade Environment. Crop Sci. 39, 202-208. WPŁYW REGULATORÓW WZROSTU NA ZADARNIENIE MURAW TRAWNIKOWYCH O ZRÓŻNICOWANYM UDZIALE ŻYCICY TRWAŁEJ Streszczenie. Procesy fizjologiczne roślin mogą być modyfikowane przez związki organiczne zwane regulatorami wzrostu. Celem badań było określenie oddziaływania wybranych regulatorów wzrostu: Moddus 250 EC, Bercema CCC i Flordimex 420 SL na zadarnienie mieszankowych muraw trawnikowych, w których elementem modyfikującym był procentowy udział życicy trwałej (Lolium perenne L.) odmiany Inka. Badania prowadzono na polu doświadczalnym Uniwersytetu Przyrodniczo-Humanistycznego w Siedlcach (52 10 N; 22 17 E) w latach 2003-2005. Zastosowanie regulatorów wzrostu modyfikowało stan zadarnienia badanych mieszanek trawnikowych. Tendencja wzrostowa była widoczna w przypadku zastosowania Bercemy CCC. Na ten regulator wzrostu najsilniej reagowały mieszanki z 20% i 40% udziałem życicy trwałej. Najniższy stopień zadarnienia zanotowano dla mieszanki z 20% udziałem życicy trwałej po zastosowaniu Flordimexu. Na stopień zadarnienia badanych mieszanek trawnikowych istotny wpływ miała interakcja procentowego udział życicy trwałej w mieszankach i zastosowanych regulatorów wzrostu. Słowa kluczowe: chlorek 2-chloroektylotrójmetyloamoniowy, etefon, gazon, Inka, Lolium perenne, trawnik, trineksapak etylu Accepted for print Zaakceptowano do druku: 24.05.2011 Agricultura 10(3) 2011