Turk J Agric For30 (2006) 137-144 - PDF document

Turk J Agric For30 (2006) 137-144 use and ile (%ama ona yakÝn bir yabancÝ ot kontrolŸ saÛlamÝßtÝr. Pancar ve ßeker verimi bakÝmÝndan, Kontrol (67.9 ve 10.1 t ha kez Weed control in sugar beet is very important and themethods applied have been changing with therequirements of each time period. In previous times,weeds were controlled by hand, and then by hand hoeing(Schweizer and May, 1993). Coupled with decreases inthe labour force, mechanisation began to be introducedinto farming practices, which resulted in a replacement ofhand hoeing by herbicide spraying and tractor hoeing.The effectiveness of pre-emergence residualherbicides decreases with reductions in rainfall or soil wetcontent. Furthermore, they reduce the root yield of sugarbeet under heavy rainfall due to phytotoxic action on thesugar beet as a result of their high effectiveness(Campagna et al., 2000). As a consequence, theapplication of post-emergence herbicides has becomemore and more important. Considering the insufficienteffectiveness of one time high-dose herbicide applicationson weeds, a low-dose technique of post-emergence forweed control was adopted in the 1980s (Schweizer andMay, 1993; May, 1996; SchŠufele, 2000). Severalherbicide residues were found in soils (Eronen andMutanen, 2000) The usage of low-dose herbicide twiceor more not only increases their effectiveness on weedsbut also decreases the amounts of their residues in soils.On the other hand, methods of mechanical weed control,especially tractor hoes, were also developed. After severalnew types of tractor hoes were developed, trials werecarried out to make their usage widespread (Miller andFornstrom, 1989; Tugnoli et al., 2002).Efficient weed control in sugar beet could increaseyield by 25%-40% in Turkey, where weed control ismainly performed by hand (…zgŸr 1980; GŸrsoy, 1982).In 83% of the total sugar beet growing areas, weeds arecontrolled by implementing firstly hand hoeing betweenthe rows, secondly thinning with hand hoeing within therows and finally hand hoeing between the rows.Consequently, this method gives very good weed control.area. However, when tractor hoeing only is employed,weeds over rows remain and additional hand hoeing isthen needed (…zgŸr and Kaya, 2003).In sugar beet cultivation, research has been done onweed control not only through the application of low-dose post-emergence herbicides but also by tractor hoe(…zgŸr and Kaya, 2000; Buzluk and Acar, 2002). Relatively efficient weed control was achieved withlow-dose herbicide mixtures applied 3 times (…zgŸr andKaya, 2000). On the other hand, the results indicatedthat treatments with different tractor hoes also producedrelatively satisfactory weed control (Buzluk and Acar,2002). The disadvantage of using a low-dose herbicide isthat it is more expensive than hand hoeing. However, thecost of hand labour is getting higher and higher. Tractorhoeing is efficient for the control of inter-row weeds butnot within the rows, and this can be regarded as one ofits disadvantages.With the aim of obtaining satisfactory weed controland complete mechanisation in sugar beet, we tested theeffects of an alternative method involving tractor hoeingcombined with post-emergence reduced herbicidedosages on weed control, and on root yield and quality.Materials and MethodsThe study was carried out in Etimesgut trial field ofthe Sugar Institute during 2002-2004. The trials,including 54 plots, were established in an area of 3623m2in a randomised complete block design with 6replications. Plots were 2.25 m wide (5 rows) and 10 mlong. Harvesting plots were 1.35 m wide (3 rows) and7.4 m long.The cultivar Leila, obtained from KleinwanzlebenerSaatzucht A.G. Ð Einbeck (Germany), treated withfungicides (hymexazol and thiram) and an insecticide(imidacloprid), was used in this study. In the soilpreparation in autumn, stubble tillage was done at the tiltof shadow following the harvest of cereals. To allowvolunteer cereals and other weed seeds to germinate, thetrial sites were irrigated and then ploughed. After therecommended fertilisers were applied to the soil in aconventional way, the trial field was ploughed again. Forseed bed preparation in spring, the remaining part of thefertilisers was applied to the soil, and then the trial fieldwas drilled with Kombi-krŸm. The sowing was thenperformed by mechanical precision drilling machine with5 rows, in 45 cm row width and at 8 cm seed spacing.The other cultivation techniques were implemented in theconventional way.A hand hoe with a sharpened blade of 15 cm and ahandle of 140-150 cm was used in the control treatment.A tractor hoe having 6 rows, 2.5 cm working width, 6-goose foot, long-nosed 12 blades, 3-8 cm working depth,Integrated Weed Control in Sugar Beet through Combinations of Tractor Hoeing and Reduced Dosages of a Herbicide Mixture Betanal Progress OF [Phenmedipham (9.2%) +Betanal Progress OF [Phenmedipham (9.2%) +()-1], andLontrel 100 [Clopyralid (12.6%), 0.5 l h-1]. The herbicidemixes were applied post-emergence by a knapsacksprayer, which had flat fan nozzles with a distance of 45cm between nozzles (nozzle number 11002, 220 l h-1volume capacity).All sprays were applied at the cotyledon stage of theweeds. Other implementations were carried outaccording to the growth stage of the sugar beet plants(Table 1).After implementing all treatments, the weeds in alltrial plots were counted in the area of 1 m2by a tool withthe dimensions of 0.185 x 1.35 m (TKB, 1996). Theweed species were identified according to Davis (1965-88) and the identified weed species and density are givenin Table 2.Effectiveness of weed control was determined byAbbottÕs formula after calculating the angle values of theweed density per plot. The data were tabulated andevaluated through analyses of variance using a statisticspackage, Mstats-C Version 1.42. Then DuncanÕs test wasused to determine the differences among the means ofthe treatments. ResultsThe results of the trials, presented as means of theyears of 2002, 2003 and 2004, are shown in Figures 1-5. The treatments of hand hoeing twice plus thinning(control) and tractor hoeing twice plus thinning producedthe lowest weed densities. All other treatments producedhigher weed densities.In terms of effectiveness of weedsignificant. The others, compared with the control, Cotyledon 2-4 true leaves4-6 true leaves8-10 true leaves2. 2x HH + T (control)Hand hoeingThinning by hand hoeHand hoeing3. 2x TH + TTractor hoeingThinning by hand hoeTractor hoeing4. 2x HBPO+P+L mix BPO+P+L mix Thinning by hand5. 2x H + 1x THBPO+P+L mix BPO+P+L mix Thinning by handTractor hoeing6. 1x H + 1x THBPO+P+L mix Thinning by handTractor hoeing7. 1x H + T + 1x THBPO+P+L mix Thinning by hand hoeTractor hoeing8. 3x HBPO+P+L mix BPO+P+L mix BPO+P+L mix Thinning by hand9. 3x H + 1x THBPO+P+L mix BPO+P+L mix BPO+P+L mix Thinning by handTractor hoeing Integrated Weed Control in Sugar Beet through Combinations of Tractor Hoeing and Reduced Dosages of a Herbicide Mixture Table 2. Weed species and average density in the trial field in 2002-2004.200220032004AverageS.Wats.5.853.533.230.8L.-0.70.50.4Schkuhr--0.20.1L.4.59.78.87.7L.1.31.32.71.8L.1.70.80.20.9L.--1.30.4(L.) Webb ex Prantl-0.50.30.3(L.) P.Beauv.--0.30.1L.0.70.20.20.4sp.0.2-0.80.3Lam.--0.80.3L.3.01.56.73.7L.-0.30.70.3L.--0.20.1L.--0.20.1L.--0.20.1L.13.21.311.78.6(L.) Hill0.3-0.50.3Total30.769.869.556.7 13.78.4 -2)Effectiveness of weed control (%)* percentage reduction in the number of weeds vs. the untreated control set at 100HH: Hand hoeing, T: Thinning, TH: Tractor hoeing, H: Herbicide mix Figure 1. Mean effectiveness of weed control and weed density of the treatments in 2002-2004 (P ) results as the control and the differences among thetreatment means were not statistically significant.Although higher root yields were obtained withtractor hoeing twice plus thinning and herbicide 3 timestreatments, there was no significant difference whencompared to the other treatments, i.e. tractor hoeingtwice plus thinning (67 t ha-1), herbicide 3 times (67 t-1), herbicide once plus thinning plus tractor hoeingonce (65 t ha-1), herbicide 3 times plus tractor hoeingonce (64.3 t ha-1) and herbicide twice plus tractor hoeingonce (63.7 t ha-1) (Figure 2).The differences among the mean sugar yields of thesetreatments were statistically the same as the control(10.1 t ha-1): herbicide 3 times (10 t ha-1), tractor hoeingtwice plus thinning (10 t ha-1), herbicide twice plustractor hoeing once (9.7 t ha-1), herbicide 3 times plustractor hoeing once (9.7 t ha-1) and herbicide once plusthinning plus tractor hoeing once (9.6 t ha-1). While thehighest sugar yields were obtained with the treatmentsinvolving herbicide 3 times and tractor hoeing twice plusthinning, no treatment resulted in a loss of 46% rootyield and 48% sugar yield (Figures 2 and 3). There wereno differences among the treatments in terms of qualityparameters such as sugar content, extractable sugarcontent, and the contents of Na, K and a-amino N(Figures 4 and 5).Even though the effectiveness of weed control byherbicide treatment 3 times was lower than that in thecontrol and tractor hoeing twice plus thinning, the rootand sugar yields of herbicide 3 times were similar to theyields of these treatments. On the other hand, while theeffectiveness values of weed control by herbicide twiceplus tractor hoeing once, herbicide once plus thinning plustractor hoeing once, herbicide 3 times, and herbicide 3times plus tractor hoeing once were comparably low, theyproduced as satisfactory root and sugar yield as thecontrol treatment did.R. KAYA, Þ. BUZLUK AB67A65AB58C63.7ABC61BC67A67.9A36.5D0105060UntreatedHH+T+HH(control)TH+T+THH+HH+H+THH+THH+T+THH+H+HH+H+H+THRoot yield (t ha- 1 )HH: Hand hoeing, T: Thinning, TH: Tractor hoeing, H: Herbicide mix Figure 2. Mean root yields of the treatments in 2002-2004 (P ) Figure 3. Mean sugar yields of the treatments in 2002-2004 (P ) D10.1A10A9.3BC9.7AB8.8C9.6AB10A9.7AB02461012UntreatedHH+T+HH(control)TH+T+THH+HH+H+THH+THH+T+THH+H+HH+H+H+THSugar yield (t ha-1)HH: Hand hoeing, T: Thinning, TH: Tractor hoeing, H: Herbicide mix same way,their root and sugar yields were naturally not AAAAAAAAAAABABAABAABC A A A A A A A A A0.00.51.01.53.03.54.55.0UntreatedHH+T+HH(control)TH+T+THH+HH+H+THH+THH+T+THH+H+HH+H+H+THmeq/100 g sugar beeta-amino N AA Figure 4. Mean contents of Na, K and a-amino N of the treatments in 2002-2004 (P ) ABABABAAABABAB1011121315161819UntreatedHH+T+HH(control)TH+T+THH+HH+H+THH+THH+T+THH+H+HH+H+H+TH% HH: Hand hoeing, T: Thinning, TH: Tractor hoeing, H: Herbicide mix A A A A A A A A A Figure 5. Mean sugar and extractable sugar contents of the treatments in 2002-2004(P ) contrast, the low-dose post-emergence applications werefound to give a satisfactory result (Campagna et al.,Tugnoli et al. (2002) suggested that only mechanicalimplementations currently available do not appear to becapable of supplanting chemical methods entirely since acertain amount of manual work on the rows would beneeded to stay on top of the weeds. Ollson (1996) alsoreported that good weed control and good sugar yieldwere obtained from tractor hoeing twice with harrowingsplus herbicide twice. Considering these results, thinningwith a hand hoe plus tractor hoeing twice produced agood result. On the other hand, low-dose post-emergencesprayings twice in combination with tractor hoeing andlow dose spraying once plus thinning with a hand hoe incombination with tractor hoeing gave a satisfactoryLow-dose herbicide applied 3 times produced a goodresult again as suggested by …zgŸr and Kaya (2000).Scott et al. (1979) stated that weeds that emergeafter sugar beet plant have 8 or more leaves are lesslikely to affect yield, and sugar beet can tolerate thepresence of weeds. Schweizer (1981) suggested thatweed numbers were less well related to root yield losseswhen weeds had been treated with herbicides, and theirgrowth had been suppressed during the growing season.Brandes et al. (1998) also reported that a certaininfestation of weed could be tolerated. Likewise, theresults in this study showed that an infestation of 21%weeds did not result in a significant loss of root and sugarOur results indicated that no treatment gave a 54%loss of root yield compared to hand hoeing twice plusthinning. As Schweizer and Dexter (1987) had stated,competition from uncontrolled annual weeds can reduceroot yield by 26%-100%.In contrast to Brandes et al.Õs (1998) findings butconsistent with …zgŸr and Kaya (2000), 2 sprayings werenot efficient. In addition, our results suggested that onemore spraying was necessary for effective weed control.In line with our results, May (1996) reported that 3 low-dose sprayings were expedient.At the same time, our study showed that when weedswere not controlled at all, weed growth resulted in higherlosses by 46% for beet yield and 48% for sugar yieldthan the losses (24%-40%) stated by …zgŸr (1980) andGŸrsoy (1982). In terms of sugar content, extractablesugar content, and the contents of Na, K and a-amino N,our results are in line with those reported by Campagnaet al. (2000).R. KAYA, Þ. BUZLUK Brandes, A., W.R. SchŠufele and W. Benz. 1998. EinflussUnterschiedlicher Unkrautdeckungsgrade auf den Ertrag vonZuckkerrŸben, in: Proceedings of the 61stIIRB Congress,Brussels: pp. 419-421.Buzluk, Þ. and A.Ü. Acar. 2002. Þeker pancarõnda deÛißik apalamasistemleri ve yabancõ ot mŸcadelesinin verim ve kalite Ÿzerindekietkileri. Tarõm Bilimleri Dergisi, 8: 171-179.Campagna, G., M. Zavanella, P. Vecchi and F. Magri. 2000. Sugar beetweed control: Yield in relation with herbicide selectivity andaction, in: Proceedings of the 63rdIIRB Congress, Interlaken, pp.541-545.Davis, P.H. 1965-1988. Flora of Turkey and the East Aegean Islands,University of Edinburgh, Vol: 1, 2, 5, 6, 7, 9, 10, Edinburgh.Eronen, L. and R. Mutanen. 2000. Ethofumesate Residues inMonoculture Soils of Sugar Beet in Finland, in: Proceedings of therdIIRB Congress, February 2000, Interlaken: pp. 511-514.GŸrsoy, O.V. 1982. Yabancõ Ot KontrolŸnŸn Temel Esaslarõ ve ÞekerPancarõ Tarõmõndaki Tatbikatõ. T.Þ.F.A.Þ. Þeker EnstitŸsŸYayõnlarõ, Ankara.May, M. 1996. Low dose systems of weed control. British Sugar BeetRev. 64: 10-11. Miller, S.D. and K.J. Fornstrom. 1989. Weed control and labourrequirements in sugarbeet. J. Sugar Beet Res. 26: 1-9.Ollson, R. 1996. Some results from trials with mechanical weed controlin sugar beet in Sweden. IIRB Study Group on Weed Control,…zgŸr, O.E. 1980. TŸrkiye Þeker Pancarõ Tarõmõnda Optimum ‚apalamaSayõsõnõn Belirlenmesi. T.Þ.F.A.Þ. Þeker EnstitŸsŸ Yayõnlarõ‚alõßma YõllõÛõ, 1977-1980, No: 4: 26-28.…zgŸr, O.E. and R. Kaya. 2000. Þeker Pancarõnda Yabancõ Ot KontrolŸ.Þeker EnstitŸsŸ Raporu, Ankara.…zgŸr, O.E. and R. Kaya. 2003. 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