COMPARISON OF FLORASULAM + 2,4-D APPLICATION EFFECT IN WHEAT, BARLEY AND OAT CULTIVATED IN MONOCROPS AND IN TWO-SPECIES MIXTURES*

Comparison of florasulam... 29 Acta Sci. Pol.,, 29-37 COMPARISON OF FLORASULAM + 2,4-D APPLICATION EFFECT IN WHEAT, BARLEY AND OAT CULTIVATED IN MONOCROPS AND IN TWO-SPECIES MIXTURES* Sylwia Kaczmarek, Kazimierz Adamczewski, Kinga Matysiak Institute of Plant Protection National Research Institute in Poznań 1 Abstract. The aim of this study was to compare the herbicidal efficiency of mixture florasulam + 2,4-D (Mustang 306 SE) in spring wheat cultivar Bryza, spring barley cultivar Antek and oat cultivar Cwał sown in monocrops and two-species mixtures. Field experiments were carried out in 2005-2007 at the Experimental Station in Winna Góra (52 o 12 N; 17 o 27 E), owned by the Institute of Plant Protection National Research Institute in Poznań. Herbicyd Mustang 306 SE was applied in a dose of 0.5 dm 3 ha -1 at 3-5 leaf stage of cereals using the knapsack sprayer Gloria. The analysis of weed infestation of cereal stand was made with the quantitative-weighing method twice in the growing period (3-4 weeks after the application and 7-8 weeks after the application). Efficiency of herbicide action in mixtures was compared with its effectiveness in monocrops of individual species. From the analyses made it follows that of the cereal mixtures, the barley-oat mixture was infested in the least degree, and the wheat-oat mixture in the most degree. Strongest effect of cultivation in mixtures on reduction of weed infestation was noticeable on the control treatments, where the herbicide was not applied, whereas the cereal cultivation system (pure or mixed sowing) not always differentiated the herbicide efficiency. Cereal grain yields in mixtures after the application of mixture florasulam + 2,4-D were significantly higher than yields of at least one of the component, and yields of mixtures harvested from the control treatments exceeded grain yields of both cereal species in monocrops. Keywords: florasulam + 2,4-D, spring cereal mixtures, mixture of herbicides, weed infestation of mixtures INTRODUCTION One of the causes of an increase in weed infestation of crops with segetal species is improperly conducted crop rotation. A growing number and weight of weeds per an Corresponding author Adres do korespondencji: dr Sylwia Kaczmarek, Department of Weed Science and Plant Protection Techniques of Institute of Plant Protection National Research Institute in Poznań, W. Węgorka 20, 60-318 Poznań, e-mail: s.kaczmarek@iorpib.poznan.pl * The research was conducted within the framework of research project N N210 0229 33

30 S. Kaczmarek, K. Adamczewski, K. Matysiak area unit may be caused first of all by cereal monoculture cultivation [Adamiak and Zawiślak 1990]. Interactions that occur between field crops and weeds are stronger in simplified crop rotations, as compared with traditional ones [Wesołowski and Woźniak 1999, Adamiak et al. 2000]. This results from a reduced species biodiversity, related to the quantitative domination of several of them, as well as to weed compensation [Szymankiewicz et al. 2003]. An alternative for a very high proportion of cereals in the cropping system (about 80%) may be their cultivation in the form of mixtures. Their increased yielding potential as compared with plants in monocrops is mentioned as the main advantage of cereal cultivation in mixtures [Taylor 1978, Rudnicki and Wasilewski 1993]. Mixtures are also characterized by better abilities to take up nutrients, the more effective use of fertilizers and water, smaller infestation by diseases and pests, as well as a considerable competition towards weeds [Budzyński and Szempliński 2003]. Plant cultivation in mixtures both inter-species and inter-varietal is considered as a natural, environmentally friendly way of regulating weed infestation, which can contribute to a reduction in costs incurred to protection, as well as reduce a risk of polluting the environment and food products with remains of active substances of herbicides. The working hypothesis assumed that thanks to using the competitive abilities of cereal mixtures towards weeds herbicide application will be more effective in those crops as compared with its action in monocrops of wheat, barley and oat. The aim of this study was to estimate the effectiveness of the mixture florasulam + 2,4-D in reducing weed infestation of spring cereals cultivated in monocrops and twospecies mixtures. MATERIAL AND METHODS A strict field experiment was carried out in 2005-2007 at the Field Eperimental Station in Winna Góra (52 o 12 N; 17 o 27 E), owned by the Institute of Plant Protection NRI in Poznań. Experimental plots with an area of 16.5 m 2 were distributed in the split-plot design in four replications, with two factors: I dose of herbicide (0 i 0.5 dm 3 ha -1 ), II cereal cultivation system (pure or mixed sowing). In 2005, the experiment was carried out on the gray-brown podzolic soil formed from light loamy sands, deposited on light loam, classified as the good rye complex and the quality class Iva. In the years 2006 and 2007 the experiments were carried out on a soil of the good wheat complex, quality class IIIa, on the gray-brown podzolic soil formed from heavy loamy sands, deposited on medium-heavy loam. The study assessed the effectiveness of applying the substance florasulam + 2,4-D (Mustang 306 SE 0.5 dm 3 ha -1 ) in spring cereal mixtures, as compared with monocrops of individual components. The effect of an action of this herbicide was also considered in comparison with the control treatments (without the herbicide). The subject of this study was the spring wheat cultivar Bryza, the spring barley cultivar Antek and the oat cultivar Cwał. Herbicide applications were carried out at the 3-5 leaf stage of spring cereals (13-15 according to the BBCH scale), with a knapsack sprayer Gloria with nozzles type Tee Jet XR11003, with a sprayer tank volume of 4 dm 3, at a pressure of 1.5 bar and a spray liquid expenditure of 200 dm 3 ha -1. The analysis of weed infestation was made with the quantitative and weight method, within the sample area of each plot determined with a frame of 25 x 50 cm, in two Acta Sci. Pol.

Comparison of florasulam... 31 randomly selected places. The analysis was carried out twice during the growing period of cereals after 3-4 weeks from the date of application (37-39 according to BBCH scale) and 7-8 weeks after the application (73-75 according to BBCH scale), and the results obtained were expressed per an area of 1 m 2. After harvesting, grain yield was determined at the standard grain moisture 14%. The results of the studies were analyzed statistically according to the experimental model, in the program FR ANALWAR 4.3, developed by Franciszek Rudnicki (University of Technology and Life Sciences in Bydgoszcz). Significance of differences was determined with Tukey's confidence half-interval, at the significance level P = 0.05. The course of the weather conditions was determined based on measurements made at a field meteorological station located on the premises of the Experimental Station in Winna Góra. Meteorological conditions in the years of the study were varied. The highest precipitation in the growing season of spring cereals was observed in 2007 378.0 mm, whereas the lowest in 2005 209.8 mm. The average daily air temperature for the whole growing season of cereals ranged from 15.9 o C (in 2005) to 16.5 o C (in 2006). In 2005, the highest precipitation was recorded in May (67.5 mm), in 2006 in August (115.2 mm), and in 2007 in July (136.3 mm). The most warm months in individual years of the experiments were: July in 2005 and 2006 (with the air temperature 20.7 and 23.9 o C, respectively) and June 2007 (18.7 o C). RESULTS AND DISCUSSION Many authors report that cereal cultivation in mixtures can bring a series of benefits [Rudnicki 1994, Sobkowicz 1999, Wasilewski 1999, Gacek et al. 2000, Michalski et al. 2000, Idziak et al. 2007]. They include for instance a better yield stability in relation to monocrops, smaller infestation by diseases and pets and a reduction in weed occurrence intensity. According to Parylak et al. [1999] and Sobkowicz [1999], plants cultivated in mixtures usually show more strong competitiveness towards weeds, as a result of a better use of site conditions and due to improved adaptation properties. In the years where the present study was conducted, from 9 to 14 species of weeds occurred in spring cereal cultivation. The species which dominated weed association was Chenopodium album L., although Galium aparine L. and Viola arvensis Murray also occurred in rather large numbers. Control treatments were most infested by weeds in 2005, and then in the years 2006 and 2007. The assessment of natural competitive abilities of cereals cultivated in mixtures in relation to weeds was possible in this part of the experiment where herbicides were not used. The results obtained clearly indicate that cereal mixtures limit weed infestation more than at least one of the components composing the mixture. Additionally, from both analyses of weed infestation it follows that the lowest intensity of weeds was found in the barley-oat mixture, and the highest in the wheat-oat mixture (Tables 1, 2).

32 S. Kaczmarek, K. Adamczewski, K. Matysiak Table 1. Number of weeds in cultivation of spring cereals, pcs m 2 Tabela 1. Liczba chwastów w uprawie zbóż jarych, szt. m -2 Treatment Obiekt Mustang 306 SE -1 dm 3 ha Year Rok Mean for years 2005 2006 2007 Średnia z lat I* II** I II I II I II Wheat pszenica (P) 0 652 419 454 340 195 230 434 330 Barley jęczmień (J) 0 383 304 394 293 179 193 318 263 Oat owies (O) 0 466 386 439 314 187 206 364 302 P + J 0 419 279 300 223 168 183 296 228 P + O 0 602 291 298 261 180 198 360 250 J + O 0 278 252 242 206 168 177 229 211 Wheat Pszenica (P) 0.5 173 34 183 37 39 38 132 36 Barley Jęczmień (J) 0.5 95 14 131 23 32 27 86 21 Oat Owies (O) 0.5 150 28 169 38 35 18 118 28 P + J 0.5 84 21 125 22 27 20 79 21 P + O 0.5 128 32 129 33 35 29 97 31 J + O 0.5 78 16 112 14 28 11 72 13 Mean for dose Średnia dla dawki (A) 0 0.5 467 118 322 24 355 142 Mean for cultivation system Średnia dla sposobu uprawy (B) wheat pszenica (P) barley jęczmień (J) oat owies (O) P + J P + O J + O LSD 0.05 NIR 0,05 A 1 LSD 0.05 NIR 0,05 B 2 LSD 0.05 NIR 0,05 A(B) 3 LSD 0.05 NIR 0,05 B(A) 4 413 239 308 252 365 178 14.0 36.0 34.2 50.8 227 159 207 150 162 134 6.3 16.2 15.4 22.9 319 263 304 213 214 177 5.8 15.0 14.2 21.1 273 28 189 158 176 123 147 110 4.8 12.2 11.6 17.3 180 33 117 106 111 98 108 98 2.3 6.0 5.7 8.5 198 24 134 110 112 102 114 94 2.7 6.8 6.5 9.7 334 97 283 202 241 188 229 151 5.1 13.2 12.5 18.6 264 25 183 142 165 125 141 112 2.3 6.0 5.7 8.5 * I weed infestation analysis made 3-4 weeks after application analiza zachwaszczenia wykonana 3-4 tygodnie po zabiegu ** II weed infestation analysis made 7-8 weeks after application analiza zachwaszczenia wykonana 7-8 tygodni po zabiegu 1 least significant difference for a dose of herbicide (A) najmniejsza istotna różnica dla dawki herbicydu (A) 2 least significant difference for cereal cultivation system (B) najmniejsza istotna różnica dla sposobu uprawy zbóż (B) 3 least significant difference for interaction between factors A and B, for constant B najmniejsza istotna różnica dla interakcji między czynnikami A i B, dla stałego B 4 least significant difference for interaction between factors A and B, for constant A najmniejsza istotna różnica dla interakcji między czynnikami A i B, dla stałego A Based on the average of the years of the study it can be stated that during the first analysis of weed infestation the number of weeds in mixtures with barley (wheat + barley and barley + oat) was significantly less in comparison with the number of weeds in monocrops of individual cereal species. The wheat-oat mixture, in turn, was characterized by smaller weed infestation as compared with oat sown in pure sowing (Table 1). In 2005 the count of weeds in the barley-oat mixture was definitely lower than in both species in monocrops, and in the wheat-barley mixture, as compared with wheat in pure sowing. No significant differences were found in the count of weeds Acta Sci. Pol.

Comparison of florasulam... 33 between the wheat-oat mixture and monocrops of both components. In 2006 the mixtures were characterized by a lower weed infestation than each of their components. The results obtained in 2007 did not differ from the average. Also significant effect of cereal mixtures on weed weight reduction on the control treatments was observed (Table 2). The average from the years of the study indicates that the fresh weight of weeds collected from the wheat-oat and barley-oat mixtures was lower than from individual species sown in monocrops. The wheat-barley mixture was characterized by lower weed infestation (fresh weed weight) than wheat in pure sowing. Only the results obtained in 2007 differed from the average of the years of the study. It was observed then that weight of weeds was less in the wheat-barley mixture than in monocrops of both species. Table 2. Fresh weight of weeds in cultivation of spring cereals, g m 2 Tabela 2. Świeża masa chwastów w uprawie zbóż jarych, g m -2 Treatment Obiekt Mustang 306 SE -1 dm 3 ha Year Rok 2005 2006 2007 Mean from years Średnia z lat I* II** I II I II I II Wheat pszenica (P) 0 1151.4 1673.3 253.3 191.3 169.6 400.7 524.7 755.1 Barley jęczmień (J) 0 724.0 906.6 231.7 156.0 143.0 221.3 366.2 428.0 Oat owies (O) 0 944.1 1107.6 243.7 166.9 158.0 282.6 448.6 519.0 P + J 0 704.7 770.7 225.4 131.3 127.3 217.5 352.5 373.2 P + O 0 842.4 733.2 224.8 138.2 143.8 235.9 403.7 369.1 J + O 0 577.1 670.7 210.9 123.5 123.5 184.2 303.9 326.2 Wheat pszenica (P) 0.5 70.9 30.5 69.0 14.9 11.1 9.3 50.3 18.2 Barley jęczmień (J) 0.5 35.4 13.2 53.5 6.2 6.5 4.2 31.8 7.9 Oat owies (O) 0.5 60.0 28.9 61.0 8.4 6.8 4.1 42.6 13.8 P + J 0.5 28.7 13.0 46.7 5.1 4.3 2.7 26.6 6.9 P + O 0.5 38.3 20.9 56.3 7.6 4.8 6.6 33.1 11.7 J + O 0.5 29.3 10.4 41.3 2.9 4.2 2.0 25.0 5.1 Mean for dose Średnia dla dawki (A) 0 0.5 824.0 43.8 977.0 19.5 231.6 54.6 Mean for cultivation system Średnia dla sposobu uprawy (B) wheat pszenica (P) 611.1 851.9 161.1 barley jęczmień (J) 379.7 459.9 142.6 oat owies (O) 502.1 568.3 152.4 P + J 366.7 391.8 136.0 P + O 440.4 377.1 140.5 J + O 303.2 340.6 126.1 LSD 0.05 NIR 0,05 A 1 LSD 0.05 NIR 0,05 B 2 LSD 0.05 NIR 0,05 A(B) 3 LSD 0.05 NIR 0,05 B(A) 4 17.85 45.95 43.74 64.99 15.39 39.59 37.69 55.99 2.95 7.60 7.24 10.75 for explanations, see Table 1 objaśnienia pod tabelą 1 151.2 7.5 103.1 81.1 87.6 68.2 72.9 63.2 2.51 6.45 6.14 9.12 144.2 6.3 90.3 74.8 82.4 65.8 74.3 63.9 1.81 4.66 4.43 6.59 257.0 4.8 205.0 112.7 143.3 110.1 121.3 93.1 4.54 11.68 11.12 16.52 399.9 34.9 287.5 199.6 245.6 189.5 218.4 164.4 6.19 15.93 15.16 22.52 461.8 10.6 386.7 217.9 266.4 190.1 190.4 165.6 5.23 13.45 12.80 19.02 During the next analysis of weed infestation (on average for years) a significant effect of cereal cultivation in mixtures on a reduction of the number and weight of weeds in relation to both components in monocrops was indicated (Tables 1, 2). Only in 2007 no significant differences were observed between the number of weeds in the

34 S. Kaczmarek, K. Adamczewski, K. Matysiak wheat-oat mixture and the number of weeds in pure sowing of oat and between the fresh weight of weeds in the wheat-barley mixture and the weight of weeds in pure sowing of barley. The effectiveness of action of the mixture of substances florasulam + 2,4-D, determined on the basis of the number and fresh weight of weeds, was usually higher in spring cereal mixtures than in monocrops of individual species (Tables 1, 2). Just as in the control treatments, the barley-oat mixture was the least infested, and the wheat-oat mixture the most. The analysis of weed infestation (on average of the years 2005-2007) made after 3-4 weeks after the application indicated that the herbicide applied in wheat and barley mixtures resulted in a stronger reduction in weed number than in wheat in monocrops. In the barley-oat mixture the number of weeds was smaller as compared with oat in monocrop. In the wheat-oat mixture, a smaller number of weeds was observed in relation to both components. In the years 2005 and 2007 such relations were not found in the case of mixtures with oat. Reduction in weed fresh weight in mixtures in relation to monocrops during the first assessment was confirmed statistically (on average for 2005-2007) only for the wheat-barley mixture in comparison with wheat in monocrop. Such an effect was not observed in 2005. In 2006, a significantly less weed weight was found in wheat-oat mixtures than in wheat in monocrop; and in the barley-oat mixture in relation to both components of the mixture. Analysis of weed infestation made after 7-8 weeks from the application proved the more effective action of the herbicide Mustang 306 SE in a dose of 0.5 dm 3 ha -1 on the wheat-barley mixture than on wheat in monocrop, and a more effective action on the barley-oat mixture in relation to oat in monocrop. The analysis of average weed weight from the years of the study did not confirmed a significant effect of the cereal cultivation system on the effectiveness of the herbicide Mustang 306 S. Only in 2006 a less weed weight was observed in the wheat-barley mixture than in wheat in pure sowing. Although the effect of cereal cultivation system on the herbicidal efficiency of the mixture florasulam + 2,4-D was not confirmed statistically in each case in the experiments, grain yields obtained from spring cereal mixtures were higher than the yields of at least one of the species composing the mixture (Table 3). The average of 2005-2007 showed that wheat-barley wheat-oat mixtures significantly exceeded wheat in pure sowing, whereas the barley-oat mixture gave definitely higher yields than both species in monocrops. This relation was not confirmed only in 2006 for yield of the wheat-oat mixture. In 2007, mixtures with wheat yielded higher in comparison with both their components. Strong effect of spring cereal cultivation in mixtures on yield was observed on the control treatments, where chemical protection against weeds was not applied (Table 3). On average from the years, all the mixtures yielded definitely better in comparison with the yield of both their components in monocrops. The differences were not proved only in 2005 for the wheat-oat mixture, which gave higher yields than wheat sown in pure sowing and in 2006 for the wheat-barley mixture, also characterizing by higher yields than wheat in pure sowing. In the experiments by Sobkowicz [2003] and Noworolnik [1994] the barley-oat mixture was characterized by significantly higher yields in relation to oat in monocrop. Michalski et al. [2000] after the application of herbicide Chwastox DF did not indicate significant differences in yield of a barley-oat mixture, as compared with monocrops of Acta Sci. Pol.

Comparison of florasulam... 35 both components. Different results, however, were obtained by Budzyński and Dubis [1994], who found that yields of a barley-oat mixture exceeded barley yields in monocrop. Table 3. Grain yield of spring cereals, t ha -1 Tabela 3. Plony ziarna zbóż jarych, t ha -1 Treatment Mustang 306 SE Year Rok Mean from years Obiekt dm 3 ha -1 2005 2006 2007 Średnia z lat Wheat Pszenica (P) 0 2.52 1.91 1.86 2.09 Barley Jęczmień (J) 0 3.12 3.07 3.30 3.16 Oat Owies (O) 0 3.00 2.21 2.68 2.63 P + J 0 3.39 2.74 3.64 3.26 P + O 0 3.07 2.42 2.98 2.82 J + O 0 3.39 3.10 3.46 3.32 Wheat Pszenica (P) 0.5 4.42 4.12 4.52 4.35 Barley Jęczmień (J) 0.5 5.10 4.73 5.21 5.02 Oat Owies (O) 0.5 4.74 4.55 4.93 4.74 P + J 0.5 4.97 4.60 5.49 5.02 P + O 0.5 4.69 4.23 5.10 4.67 J + O 0.5 5.30 5.13 5.63 5.35 Mean for dose (A) Średnia dla dawki (A) 0 0.5 3.08 4.87 2.58 4.56 Mean for cultivation system (B) Średnia dla sposobu uprawy (B) wheat pszenica (P) barley jęczmień (J) oat owies (O) P + J P + O J + O 3.47 4.11 3.87 4.18 3.88 4.35 3.02 3.90 3.38 3.67 3.33 4.12 LSD 0.05 NIR 0,05 A 1 0.053 LSD 0.05 NIR 0,05 B 2 0.136 LSD 0.05 NIR 0,05 A(B) 3 0.129 LSD 0.05 NIR 0,05 B(A) 4 0.129 for explanations, see Table 1 objaśnienia pod tabelą 1 0.053 0.136 0.129 0.129 2.99 5.15 3.19 4.26 3.81 4.57 4.04 4.55 0.041 0.106 0.101 0.150 2.88 4.86 3.22 4.09 3.69 4.14 3.75 4.34 0.027 0.037 0.066 0.074 CONCLUSIONS 1. Cultivation of cereals in mixtures on the treatments where chemical protection against weeds was not applied constituted a factor significantly reducing the number and fresh weight of weeds as compared with monocrops of individual components composing the mixtures. 2. The barley-oat mixture was characterized by the lowest weed infestation, whereas the wheat-oat by the highest. 3. It was not found explicitly that the application of mixture of the substance florasulam + 2,4-D against weeds is more effective in mixtures of spring cereals than in their monocrops. 4. Cereals cultivated in mixtures exceeded at least one of the mixture components in monocrops.

36 S. Kaczmarek, K. Adamczewski, K. Matysiak REFERENCES Adamiak E., Adamiak J., Stępień A., 2000. Wpływ następstwa roślin i stosowania herbicydów na zachwaszczenie jęczmienia jarego [Effect of crop sequence and herbicide application on weed infestation of spring barley]. Ann. Univ. Mariae Curie-Skłodowska, Sect. E, Agricultura 55, 9-15 [in Polish]. Adamiak E., Zawiślak K., 1990. Zmiany w zbiorowisku chwastów w monokulturowej uprawie podstawowych zbóż i kukurydzy [Changes in weed community in monoculture cultivation of basic cereals and maize] [In]: Ekologiczne procesy w monokulturowych uprawach zbóż. Wyd. Uniw. AM Poznań, 33-61 [in Polish]. Budzyński W., Szempliński W., 2003. Mieszanki i mieszaniny zbożowe [Cereal plant mixtures] [In:] Szczegółowa uprawa roślin, Z. Jasińska and A. Kotecki (eds.), Wyd. AR Wrocław, 257-264 [in Polish]. Budzyński W., Dubis B., 1994. Porównanie plonowania zbóż jarych w siewach czystych, międzygatunkowych i międzyodmianowych w świetle wieloletnich badań [Comparison of spring cereal yield in pure, interspecies and intervarietal sowings in the light of long-term research]. Mat. Konf. Stan i perspektywy uprawy mieszanek zbożowych, AR Poznań, 75-82 [in Polish]. Gacek E., Nadziak J., Biliński Z.R., 2000. Ograniczenie występowania chorób w zasiewach mieszanych zbóż [Limiting occurrence of diseases in mixed sowings of cereals]. Rocz. AR w Poznaniu, Rolnictwo 58, 31-38, 89-93 [in Polish]. Idziak R., Michalski T., Osiecka B., 2007. Zachwaszczenie i plonowanie mieszanek jęczmienia jarego z owsem w warunkach zróżnicowanej ochrony chemicznej [Weed infestation and yield of mixtures of spring barley with oat under conditions of differentiated chemical protection]. Zesz. Probl. Post. Nauk Rol. 516, 55-63 [in Polish]. Michalski T., Osiecka B., Kowalik I., 2000. Wpływ ochrony roślin na plony i wartość paszową jęczmienia i owsa oraz ich mieszanek [Effect of plant protection on yield and fodder value of barley and oat and their mixtures]. Rocz. AR w Poznaniu, Rolnictwo 58, 75-82 [in Polish]. Noworolnik K., 1994. Reakcja jarych mieszanek jęczmienia z owsem na gęstość siewu [Response of spring barley-oat mixtures on sowing density]. Mat. Konf. Stan i perspektywy uprawy mieszanek zbożowych, AR Poznań, 105-109 [in Polish]. Parylak D., Kordas L., Gacek E., 1999. Ocena zasiewów mieszanych zbóż jarych jako proekologicznej metody ograniczenia zachwaszczenia [Assessment of mixed sowing of spring cereals as a pro-ecological method for weed infestation limitation]. Zesz. Nauk. AR we Wrocławiu, Konferencje 22, 235-242 [in Polish]. Rudnicki F., 1994. Biologiczne aspekty uprawy zbóż w mieszankach [Biological aspects of cereal cultivation in mixtures]. Mat. Konf. Stan i perspektywy uprawy mieszanek zbożowych, AR Poznań, 7-15 [in Polish]. Rudnicki F., Wasilewski P., 1993. Badania nad uprawą jarych mieszanek zbożowych. II. Reakcja jęczmienia, owsa i pszenicy na uprawę w mieszankach [Study of spring cereal mixture cultivation. II. Response of barley, oat and wheat on cultivation in mixtures]. Rocz. AR w Poznaniu, Rolnictwo 41, 65-72 [in Polish]. Sobkowicz P., 1999. Ocena odchwaszczającego działania jarych mieszanek zbożowych [Assessment of weeding action of spring cereal mixtures]. Prog. Plant Protection/Post. Ochr. Rośl. 39(2), 687-689 [in Polish]. Sobkowicz P., 2003. Konkurencja międzygatunkowa w jarych mieszankach zbożowych [Interspecies competition in spring cereal mixtures]. Zesz. Nauk. AR we Wrocławiu, Rozprawy 194 [in Polish]. Szymankiewicz K., Jankowska D., Deryło S., 2003. Wpływ płodozmianu i monokultury oraz sposobu uprawy roli na bioróżnorodność flory zachwaszczającej pszenżyto ozime [Effect of crop rotation and monoculture and cropping system on biodiversity of flora infesting winter triticale]. Acta Agrophysica 1(4), 746-772 [in Polish]. Taylor B.R., 1978. Studies on a barley oats mixture. J. Agric. Sci. Camb. 91(3), 587-592. Acta Sci. Pol.

Comparison of florasulam... 37 Wasilewski P., 1999. Wpływ sposobów zwalczania chwastów na zachwaszczenie i plonowanie mieszanek zbożowych [Effect of weed control methods on weed infestation and yielding of cereal mixtures]. Mat. Konf. Przyrodnicze i produkcyjne aspekty uprawy roślin w mieszankach,, AR Poznań, 124-125 [in Polish]. Wesołowski M., Woźniak A., 1999. Zachwaszczenie aktualne i potencjalne zbóż jarych w różnych systemach następstwa roślin [Current and potential weed infestation of spring cereals in different systems of crop sequence]. Acta Agrobot. 5(1), 175-190 [in Polish]. PORÓWNANIE EFEKTU STOSOWANIA MIESZANINY SUBSTANCJI FLORASULAM + 2,4 D W PSZENICY, JĘCZMIENIU I OWSIE UPRAWIANYCH W SIEWACH CZYSTYCH ORAZ DWUGATUNKOWYCH MIESZANKACH Streszczenie. Celem badań było porównanie skuteczności chwastobójczej mieszaniny florasulam + 2,4-D (Mustang 306 SE) w pszenicy jarej odmiany Bryza, jęczmieniu jarym odmiany Antek oraz owsie odmiany Cwał, wysiewanych w siewach czystych i w dwugatunkowych mieszankach. Doświadczenia polowe przeprowadzono w latach 2005-2007 na terenie Stacji Doświadczalnej w Winnej Górze (52 o 12 N; 17 o 27 E), należącej do Instytutu Ochrony Roślin PIB w Poznaniu. Herbicyd Mustang 306 SE zastosowano w dawce 0,5 dm 3 ha -1 w fazie 3-5 liści zbóż z użyciem plecakowego opryskiwacza Gloria. Analizę zachwaszczenia łanu zbóż wykonywano metodą ilościowo-wagową, dwukrotnie w okresie wegetacji (3-4 tygodni po zabiegu oraz 7-8 tygodni po zabiegu). Skuteczność działania herbicydu w mieszankach porównywano z jego efektywnością w siewach czystych poszczególnych gatunków. Z przeprowadzonych analiz wynika, że spośród mieszanek zbożowych w najmniejszym stopniu zachwaszczona była mieszanka jęczmienia z owsem, a w największym pszenicy z owsem. Najsilniejszy wpływ uprawy mieszanek na redukcję zachwaszczenia uwidocznił się w obiektach kontrolnych, na których nie stosowano herbicydu, natomiast sposób uprawy zbóż (siew czysty lub mieszany) nie zawsze różnicował skuteczność chwastobójczą herbicydu. Plony ziarna zbóż w mieszankach po zastosowaniu mieszaniny florasulam + 2,4-D były istotnie wyższe od plonów przynajmniej jednego z komponentów, a plony mieszanek zebrane z obiektów kontrolnych przewyższały plony ziarna zbóż obu gatunków w siewach czystych. Słowa kluczowe: florasulam + 2,4-D, jare mieszanki zbożowe, mieszanina herbicydów, zachwaszczenie mieszanek Accepted for print Zaakceptowano do druku: 02.12.2010