The effect of sowing date, stale seedbed, row width and mechanical weed control on weeds and yields of organic winter wheat

Weed Research ◽  
2004 ◽  
Vol 44 (1) ◽  
pp. 12-20 ◽  
Author(s):  
I A Rasmussen
2017 ◽  
Vol 63 (No. 2) ◽  
pp. 82-88 ◽  
Author(s):  
Sturm Dominic J ◽  
Kunz Christoph ◽  
Peteinatos Gerassimos ◽  
Gerhards Roland

The weed suppressive ability of oilseed radish (Raphanus sativus var. oleiformis Pers.) cover crop is attributed to high competitiveness for resources and biochemical effects on weeds. The oilseed radish cover crop was sown in five treatments plus an untreated control over a period of five weeks before and three weeks after winter wheat harvest. Additionally, fertilization effects on oilseed radish biomass and weed suppression were measured. The highest biomass of the cover crop was observed 12 weeks after harvest (WAH) when the oilseed radish was sown one week after harvest (1 WAH) (2015) and five weeks before harvest (5 WBH) (2016). No differences of fertilization were observed concerning oilseed radish and weed biomass in 2015, whereby increased biomass was found after fertilization in 2016. The highest weed control efficacy of up to 83% and 90% was achieved in treatments 1 WAH (2015) and 5 WBH (2016) at 12 WAH. The early sowing of oilseed radish in winter wheat resulted in low germination and biomass yield within the field, due to low precipitation in 2015. Nevertheless, there is a high potential of early sown oilseed radish for higher weed control efficacy, which was demonstrated in 2016.  


2017 ◽  
Vol 11 ◽  
Author(s):  
Euro Pannacci ◽  
Francesco Tei ◽  
Marcello Guiducci

Three field experiments were carried out in organic winter wheat in three consecutive years (exp. 1, 2005-06; exp. 2, 2006-07; exp. 3, 2007-08) in central Italy (42°57' N - 12°22' E, 165 m a.s.l.) in order to evaluate the efficacy against weeds and the effects on winter wheat of two main mechanical weed control strategies: 1) spring tine harrowing used at three different application times (1 passage at T1; 2 passages at the time T1; 1 passage at T1 followed by 1 passage at T1 + 14 days) in the crop sowed at narrow (traditional) row spacing (0.15 m) and 2) split-hoeing and finger-weeder, alone and combined at T1, in the crop sowed at wider row spacing (0.30 m). At the time T1 winter wheat was at tillering and weeds were at the cotyledons-2 true leaves growth stage. The experimental design was a split-plot with four replicates. Six weeks after mechanical treatments, weed ground cover (%) was rated visually using the Braun–Blanquet cover-abundance scale; weeds on three squares (0.6 x 0.5 m each one) per plot were collected, counted, weighed, dried in oven at 105 °C to determine weed density and weed above-ground dry biomass. At harvest, wheat ears density, grain yield, weight of 1000 seeds and hectolitre weight were recorded. Total weed flora was quite different in the three experiments. The main weed species were: <em>Polygonum aviculare</em> L. (exp. 1 and 2), <em>Fallopia convolvulus</em> (L.) Á. Löve (exp. 1 and 3), <em>Stachys annua</em> (L.) L. (exp. 1), <em>Anagallis arvensis</em> L. (exp. 2), <em>Papaver rhoeas</em> L. (exp.3), <em>Veronica hederifolia</em> L. (exp. 3). In the winter wheat sowed at narrow rows, 2 passages with spring-tine harrowing at the same time seems to be the best option in order to reconcile a good efficacy with the feasibility of treatment. In wider rows spacing the best weed control was obtained by splithoeing alone or combined with finger-weeder. The grain yield, on average 10% higher in narrow rows, the lower costs and the good selectivity of spring-tine harrowing treatments seems to suggest the adoption of narrow rows spacing in wheat in organic and low-input farming systems.


2021 ◽  
pp. 1-14
Author(s):  
Jodie A. Crose ◽  
Misha R. Manuchehri ◽  
Todd A. Baughman

Abstract Three herbicide premixes have recently been introduced for weed control in wheat. These include: halauxifen + florasulam, thifensulfuron + fluroxypyr, and bromoxynil + bicyclopyrone. The objective of this study was to evaluate these herbicides along with older products for their control of smallseed falseflax in winter wheat in Oklahoma. Studies took place during the 2017, 2018, and 2020 winter wheat growing seasons. Weed control was visually estimated every two weeks throughout the growing season and wheat yield was collected in all three years. Smallseed falseflax size was approximately six cm in diameter at time of application in all years. Control ranged from 96 to 99% following all treatments with the exception of bicyclopyrone + bromoxynil and dicamba alone, which controlled falseflax 90%. All treatments containing an acetolactate synthase (ALS)-inhibiting herbicide achieved adequate control; therefore, resistance is not suspected in this population. Halauxifen + florasulam and thifensulfuron + fluroxypyr effectively controlled smallseed falseflax similarly to other standards recommended for broadleaf weed control in wheat in Oklahoma. Rotational use of these products allows producers flexibility in controlling smallseed falseflax and reduces the potential for development of herbicide resistance in this species.


1996 ◽  
Vol 10 (3) ◽  
pp. 526-530
Author(s):  
Jeffrey A. Koscelny ◽  
Thomas F. Peeper

The efficacy of sulfonylurea herbicides impregnated on granular fertilizers applied PPI or POST was compared to broadcast spray applications for annual broadleaf weed control in winter wheat. Henbit and bushy wallflower were controlled by chlorsulfuron or triasulfuron impregnated onto diammonium phosphate granular fertilizer applied PPI. Efficacy of these herbicides for annual broadleaf weed control was reduced by applying them POST with granular urea fertilizer carrier instead of with water carrier.


2012 ◽  
Vol 63 (2) ◽  
pp. 179-188 ◽  
Author(s):  
Cezary Kwiatkowski

A field experiment involving the cultivation of common valerian was conducted on loess soil in Abramów (Lublin region) in the period 2007-2009. Qualitative parameters of herbal raw material obtained from this plant as well as in-crop weed infestation were evaluated depending on the protection method and forecrop. Hand-weeded plots, in which a hand hoe was used, were the control. In the other treatments, weeds were controlled using various herbicides and a mechanical implement (brush weeder). Potato and winter wheat + field pea cover crop were the forecrops for common valerian crops. A hypothesis was made that the use of a brush weeder and herbicides not registered for application in valerian crops would have a positive effect on this plant's productivity and weed infestation in its crops. It was also assumed that the introduction of a cover crop would allow the elimination of differences in the forecrop value of the crop stands in question. The best quantitative and qualitative parameters of common valerian raw material as well as the largest reduction of incrop weed infestation were recorded after the application of the herbicides which were not type approved. The use of the brush weeder in the interrows also had a beneficial effect on productivity of the plant in question, but secondary weed infestation at the end of the growing season of common valerian turned out to be its disadvantage. Traditional crop protection methods used in common valerian crops were less effective in weed infestation reduction and they resulted in lower plant productivity and raw material quality. Potato proved to be a better forecrop for common valerian than winter wheat + field pea; however, this positive effect was not confirmed statistically. The following annual weeds: <i>Chenopodium album</i>, <i>Galinsoga parviflora</i>, <i>Stellaria media</i>, were predominant in the common valerian crop. Traditional weed control methods resulted in the dominance of some dicotyledonous weeds, such as <i>Viola arvensis</i>, <i>Galium aparine</i>, <i>Capsella bursa-pastoris</i>.


1992 ◽  
Vol 117 (2) ◽  
pp. 255-259
Author(s):  
Brian A. Kahn ◽  
Raymond Joe Schatzer

The herbicides paraquat, trifluralin, and metolachlor were compared for efficacy of weed control in cowpea [Vigna unguiculata (L.) Walp.] with and without cultivation as a supplemental strategy. Herbicides also were compared against a no cultivation-no herbicide treatment (control) and against cultivation without an herbicide. Cultivation had no significant effect on seed yield, biological yield, or harvest index of cowpea. Paraquat, applied before seeding but after emergence of weeds, was ineffective for weed control and usually did not change cowpea yield from that obtained without an herbicide. Trifluralin and metolachlor more than tripled cowpea seed yield compared with that obtained without an herbicide in 1988, when potential weed pressure was 886 g·m-2 (dry weight). The main effects of trifluralin and metolachlor were not significant for cowpea seed yield in 1989, when potential weed pressure was 319 g·m-2 (dry weight). However, in 1989, these two herbicides still increased cowpea seed yield compared with that of the control and increased net farm income by more than $300/ha compared with the income obtained from the control. Chemical names used 1,1'-dimethyl-4,4' -bipyridlnium salts (paraquat); 2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl) benzenamine (trifluralin); 2-chloro-N-(2-ethyl-6 -methylphenyl)-N-(2-methoxy-l-methylethyl) acetamide (metolachlor).


2020 ◽  
Vol 34 (6) ◽  
pp. 857-862
Author(s):  
Jacob W. Fischer ◽  
Mark E. Thorne ◽  
Drew J. Lyon

AbstractRush skeletonweed is an aggressive perennial weed that establishes itself on land in the Conservation Reserve Program (CRP), and persists during cropping following contract expiration. It depletes critical soil moisture required for yield potential of winter wheat. In a winter wheat/fallow cropping system, weed control is maintained with glyphosate and tillage during conventional fallow, and with herbicides only in no-till fallow. Research was conducted for control of rush skeletonweed at two sites in eastern Washington, Lacrosse and Hay, to compare the effectiveness of a weed-sensing sprayer and broadcast applications of four herbicides (aminopyralid, chlorsulfuron + metsulfuron, clopyralid, and glyphosate). Experimental design was a split-plot with herbicide and application type as main and subplot factors, respectively. Herbicides were applied in the fall at either broadcast or spot-spraying rates depending on sprayer type. Rush skeletonweed density in May was reduced with use of aminopyralid (1.1 plants m−2), glyphosate (1.4 plants m−2), clopyralid (1.7 plants m−2), and chlorsulfuron + metsulfuron (1.8 plants m−2) compared with the nontreated check (2.6 plants m−2). No treatment differences were observed after May 2019. There was no interaction between herbicide and application system. Area covered using the weed-sensing sprayer was, on average, 52% (P < 0.001) less than the broadcast application at the Lacrosse location but only 20% (P = 0.01) at the Hay location. Spray reduction is dependent on foliar cover in relation to weed density and size. At Lacrosse, the weed-sensing sprayer reduced costs for all herbicide treatments except aminopyralid, with savings up to US$6.80 per hectare. At Hay, the weed-sensing sprayer resulted in economic loss for all products because of higher rush skeletonweed density. The weed-sensing sprayer is a viable fallow weed control tool when weed densities are low or patchy.


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