Effect of Seeding Rate and Weed Control on Glyphosate-Resistant Alfalfa Establishment

2011 ◽  
Vol 25 (2) ◽  
pp. 230-238 ◽  
Author(s):  
Calvin F. Glaspie ◽  
S. Ann McCordick ◽  
Timothy S. Dietz ◽  
James J. Kells ◽  
Richard H. Leep ◽  
...  
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Field Experiments ◽  
Plant Density ◽  
Forage Quality ◽  
Stand Density ◽  
Seeding Rate ◽  
Growing Seasons ◽  
Herbicide Treatment ◽  
Alfalfa Field

The introduction of glyphosate-resistant (GR) alfalfa offers a new weed management system for alfalfa establishment; however, alfalfa seeding rates are based on conventional cultivars. Determining optimum seeding rates allows forage producers to maximize yield, quality, and profitability with GR alfalfa. Field experiments were established in 2005 and 2006 to determine the effect of seeding rate and weed control on GR alfalfa yield, forage quality, and persistence up to 3 yr after establishment. Seeding rates of 4.5, 9.0, and 18 kg ha−1were evaluated. Weed control methods during the seeding year included no herbicide, glyphosate applied once before the first harvest, and glyphosate applied once before the first harvest and then 7 to 10 d following subsequent harvests. Alfalfa yield was greater at higher seeding rates and when weeds were removed with glyphosate. Season forage yields were the greatest with the 18 kg ha−1seeding rate and where no herbicide was applied. Weed biomass often was lower at the higher seeding rates and was 91 to 98% lower in the glyphosate treatments compared to the nontreated. Forage quality was not affected by seeding rate but varied by herbicide treatment depending on establishment year. Plant density increased with seeding rate and treatment effects persisted for three growing seasons. Herbicide treatment did not affect stand density as greatly as seeding rate and did not influence stand longevity.

Sugarbeet tolerance when dimethenamid-P follows soil-applied ethofumesate and S-metolachlor

2019 ◽  
Vol 33 (03) ◽  
pp. 431-440
Author(s):  
Thomas J. Peters ◽  
Andrew B. Lueck ◽  
Aaron L. Carlson
Keyword(s):  
Control System ◽  
Weed Control ◽  
Field Experiments ◽  
Plant Density ◽  
Stand Density ◽  
Sucrose Content ◽  
Root Yield ◽  
Visible Injury ◽  
Herbicide Treatments

AbstractSugarbeet growers only recently have combined ethofumesate, S-metolachlor, and dimethenamid-P in a weed control system for waterhemp control. Sugarbeet plant density, visible stature reduction, root yield, percent sucrose content, and recoverable sucrose were measured in field experiments at five environments between 2014 and 2016. Sugarbeet stand density and stature reduction occurred in some but not all environments. Stand density was reduced with PRE application of S-metolachlor at 1.60 kg ai ha–1 and S-metolachlor at 0.80 kg ha–1 + ethofumesate at 1.68 kg ai ha–1 alone or followed by POST applications of dimethenamid-P at 0.95 kg ai ha–1. Sugarbeet visible stature was reduced when dimethenamid-P followed PRE treatments. Stature reduction was greatest with ethofumesate at 1.68 or 4.37 kg ha–1 PRE and S-metolachlor at 0.80 kg ha–1 + ethofumesate at 1.68 kg ha–1 PRE followed by dimethenamid-P at 0.95 kg ha–1 POST. Stature reduction ranged from 0 to 32% 10 d after treatment (DAT), but sugarbeet recovered quickly and visible injury was negligible 23 DAT. Although root yield and recoverable sucrose were similar across herbicide treatments and environments, we caution against the use of S-metolachlor at 0.80 kg ha–1 + ethofumesate at 1.68 kg ai ha–1 PRE followed by dimethenamid-P at 0.95 kg ha–1 in sugarbeet.

Economics of integrated weed management in herbicide-resistant canola

Weed Science ◽  
2006 ◽  
Vol 54 (1) ◽  
pp. 138-147 ◽  
Author(s):  
Bharat M. Upadhyay ◽  
Elwin G. Smith ◽  
G. W. Clayton ◽  
K. N. Harker ◽  
R. E. Blackshaw
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Field Experiments ◽  
Production Systems ◽  
Statistical Significance ◽  
Integrated Weed Management ◽  
Seeding Rate ◽  
Herbicide Resistant ◽  
Leaf Stage ◽  
Weed Removal

Integrated weed management (IWM) decision strategies in herbicide-resistant canola-production systems were assessed for net returns and relative risk. Data from two field experiments conducted during 1998 to 2000 at two locations in Alberta, Canada, were evaluated. A herbicide-based experiment included combinations of herbicide system (glufosinate-, glyphosate-, and imazethapyr-resistant canola varieties), herbicide rate (50 and 100% of recommended dose), and time of weed removal (two-, four-, and six-leaf stages of canola). A seed-based experiment included canola variety (hybrid and open-pollinated), seeding rate (100, 150, and 200 seeds m−2), and time of weed removal (two-, four-, and six-leaf stages of canola). For the herbicide-based experiment, strategies with glyphosate were profitable at Lacombe, but both imazethapyr and glyphosate strategies were profitable at Lethbridge. Weed control at the four-leaf stage was at least as profitable as the two-leaf stage at both sites. For the seed-based experiment, the hybrid was more profitable than the open-pollinated cultivar, seed rates of 100 and 150 seeds m−2were more profitable than 200 seeds m−2, and weed control at the two- and four-leaf stages was more profitable than at the six-leaf stage. When risk of returns and statistical significance was considered, several strategies were included in the risk-efficient set for risk-averse and risk-neutral attitudes at each location. However, the glyphosate-resistant cultivar, the 50% herbicide rate, and weed control at four-leaf stage were more frequent in the risk-efficient IWM strategy set. The open-pollinated cultivar, 200 seeds m−2rate, and weed control at the six-leaf stage were less frequent in the set. The risk-efficient sets of IWM strategies were consistent across a range of canola prices.

Weed Management Programs with Pyroxasulfone in Field Corn (Zea mays)

2017 ◽  
Vol 31 (4) ◽  
pp. 496-502 ◽  
Author(s):  
Daniel O. Stephenson ◽  
Jason A. Bond ◽  
James L. Griffin ◽  
Randall L. Landry ◽  
Brandi C. Woolam ◽  
...  
Keyword(s):  
Zea Mays ◽  
Weed Control ◽  
Weed Management ◽  
Field Experiments ◽  
Management Program ◽  
Post Treatment ◽  
Palmer Amaranth ◽  
Corn Yield ◽  
Field Corn ◽  
Herbicide Treatment

Field experiments were conducted in Louisiana and Mississippi from 2011 through 2013 to evaluate crop injury, weed control, and yield in field corn following pyroxasulfone applied PRE and POST. Pyroxasulfone PRE or POST did not injure corn at any evaluation. Barnyardgrass control was not improved with the addition of any POST treatment to pyroxasulfone alone or atrazine plus pyroxasulfone PRE; however, all POST treatments increased barnyardgrass control to at least 95% at all evaluations following atrazine PRE. All treatments that contained a PRE followed by POST application controlled browntop millet ≥90% at all evaluations. All POST treatments increased ivyleaf morningglory control to ≥92% following atrazine or pyroxasulfone alone PRE. However, control with atrazine plus pyroxasulfone PRE was similar or greater 28 d after POST than all treatments that received a POST application. In the absence of a POST treatment, pyroxasulfone or atrazine plus pyroxasulfone PRE controlled Palmer amaranth 93 to 96% at all evaluations, but atrazine alone PRE provided 84, 82, and 66% control 7, 14, and 28 d after POST, respectively. All programs that contained a PRE followed by POST herbicide treatment controlled Palmer amaranth >90% at all evaluations. Corn yield following all treatments except atrazine alone PRE and the nontreated were similar and ranged from 10990 to 12330 kg ha−1. This research demonstrated that pyroxasulfone can be a valuable tool for weed management in a corn weed management program.

Glyphosate-Resistant Alfalfa Response to Harvest Frequency and Weed Management

2012 ◽  
Vol 26 (3) ◽  
pp. 399-404 ◽  
Author(s):  
Doo-Hong Min ◽  
Timothy S. Dietz ◽  
Wesley J. Everman ◽  
Andrew J. Chomas ◽  
James J. Kells ◽  
...  
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Forage Quality ◽  
Stand Density ◽  
Forage Yield ◽  
Moderate Intensity ◽  
Weed Invasion ◽  
Harvest Intensity ◽  
Harvest Frequency ◽  
Weed Removal

Glyphosate-resistant (GR) alfalfa offers growers new options for weed control in alfalfa. One potential benefit of using GR alfalfa is increased longevity of an alfalfa stand under frequent harvests. It was hypothesized that GR alfalfa would have a greater longevity because of removal of weed interference with minimal crop injury. To study GR alfalfa yield, weed invasion, alfalfa stand persistence, and relative forage quality (RFQ), a field experiment with three weed control methods (no herbicide, glyphosate, and hexazinone) under two harvest frequencies (high and moderate) was established in August 2003 at the Michigan State University Agronomy Farm in East Lansing, MI. Forage yield of established alfalfa was not adversely affected by herbicide treatments. There were no differences in weed biomass between alfalfa treated with glyphosate and that treated with hexazinone, except in 2007. Average GR alfalfa stand density decreased approximately 90% (from 236 to 27 plant m−2), and yield decreased approximately 30% (from 11.04 to 7.87 Mg ha−1) during the 7-yr period (2004 to 2010) of the experiment. Stand density of GR alfalfa showed natural thinning during the 7-yr period regardless of harvest intensity or herbicide treatment. In most production years (4 out of 5 yr), relative forage quality of GR alfalfa was higher under a high-intensity harvesting system (4 to 5 harvests yr−1) than it was with a moderate intensity harvesting system (3 to 4 harvests yr−1). Relative forage quality was not affected by weed removal with herbicides in most years. Weed removal and harvest intensity in established GR alfalfa had no effect on stand persistence.

Band sowing with hoeing in organic grains: II. Evidence of improved weed management in spring wheat, oats, field peas, and flax

Weed Science ◽  
2020 ◽  
Vol 68 (3) ◽  
pp. 294-300
Author(s):  
Margaret R. McCollough ◽  
Eric R. Gallandt ◽  
Thomas Molloy
Keyword(s):  
Weed Control ◽  
Spring Wheat ◽  
Weed Management ◽  
Field Experiments ◽  
Crop Yields ◽  
Spatial Arrangement ◽  
Band Width ◽  
Seeding Rate ◽  
Standard Practice ◽  
Field Peas

AbstractThe long-term success of weed management programs requires that all crops in a rotation receive satisfactory weed control. Band sowing with inter-band hoeing has been proposed as an innovative weed management strategy for grain crops. In the band-sowing system, crops are sown in a broadcast pattern within a band of some chosen width (here we selected 12.7 cm); weeds between bands are controlled with inter-band hoeing, with or without so-called “blind cultivation,” for example, tine harrowing. Alteration of the crop spatial arrangement from typical single-line rows to a more evenly distributed pattern aims to enhance interspecific competition while reducing intraspecific competition. Field experiments, conducted in Maine in 2016 and 2017, compared band sowing with inter-band hoeing to the region’s standard practice of planting in 16.5-cm rows and tine harrowing in four test crops: spring wheat (Triticum aestivum L. ‘Glenn’), oat (Avena sativa L. ‘Colt’), field pea (Pisum sativum L. ‘Jetset’), and flax (Linum usitatissimum L. ‘Prairie Thunder’). Band sowing improved weed control relative to the standard practice, especially in crops with greater competitive ability (wheat and oat). Despite improved weed control, in most cases, yields were unaffected by treatment. While band sowing with hoeing provided improved weed control in multiple crops, further study is warranted to optimize seeding rate, band width, and inter-band width to improve crop yields.

Bio-efficacy of post emergence herbicides in boro rice nursery as well as main field and their residual effects on non-target microorganisms

2020 ◽  
Vol 57 (3) ◽  
pp. 199-210
Author(s):  
Rajib Kundu ◽  
Mousumi Mondal ◽  
Sourav Garai ◽  
Ramyajit Mondal ◽  
Ratneswar Poddar
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Field Experiments ◽  
Block Design ◽  
Resistance Index ◽  
Residual Effects ◽  
Cost Ratio ◽  
Main Field ◽  
Weed Species ◽  
Similar Treatment

Field experiments were conducted at research farm of Bidhan Chandra Krishi Viswavidyalaya, Kalyani, West Bengal, India (22°97' N latitude and 88°44' E longitude, 9.75 m above mean sea level) under natural weed infestations in boro season rice (nursery bed as well as main field) during 2017-18 and 2018-19 to evaluate the herbicidal effects on weed floras, yield, non-target soil organisms to optimize the herbicide use for sustainable rice-production. Seven weed control treatments including three doses of bispyribac-sodium 10% SC (150,200, and 250 ml ha-1), two doses of fenoxaprop-p-ethyl 9.3% EC (500 and 625 ml ha-1), one weed free and weedy check were laid out in a randomized complete block design, replicated thrice. Among the tested herbicides, bispyribac-sodium with its highest dose (250 ml ha-1) resulted in maximum weed control efficiency, treatment efficiency index and crop resistance index irrespective of weed species and dates of observation in both nursery as well as main field. Similar treatment also revealed maximum grain yield (5.20 t ha-1), which was 38.38% higher than control, closely followed by Fenoxaprop-p-ethyl (625 ml ha-1) had high efficacy against grasses, sedge and broadleaf weed flora. Maximum net return (Rs. 48765 ha-1) and benefit cost ratio (1.72) were obtained from the treatment which received bispyribac-sodium @ 250 ml ha-1. Based on overall performance, the bispyribac-sodium (250 ml ha-1) may be considered as the best herbicide treatment for weed management in transplanted rice as well as nursery bed.

Impact of cultivars and herbicides on weed management in alfalfa

2006 ◽  
Vol 86 (3) ◽  
pp. 875-885 ◽  
Author(s):  
J. R. Moyer ◽  
S. N. Acharya
Keyword(s):  
British Columbia ◽  
Weed Control ◽  
Weed Management ◽  
Forage Quality ◽  
Western Canada ◽  
Downy Brome ◽  
Weed Species ◽  
Standard Type ◽  
Southern Alberta ◽  
Medicago Sativa L

Weeds, especially dandelion (Taraxacum officinale Weber in F.H. Wigg.), tend to infest a forage alfalfa (Medicago sativa L.) stand 2 to 4 yr after establishment. To develop better weed management systems, experiments were conducted at Lethbridge, Alberta, from 1995 to 2002 and Creston, British Columbia, from 1998 to 2001, which included the alfalfa cultivars Beaver (standard type) and AC Blue J (Flemish type) and annual applications of metribuzin and hexazinone. These herbicides are registered for weed control in irrigated alfalfa in Alberta and alfalfa grown for seed. In addition, two sulfonylurea herbicides, metsulfuron and sulfosulfuron, and glyphosate were included. All of the herbicides except glyphosate controlled or suppressed dandelion and mustard family weeds. Metsulfuron at 5 g a.i. ha-1 almost completely controlled dandelion at both locations. However, after metsulfuron application at Lethbridge, dandelion was replaced with an infestation of downy brome, which is unpalatable for cattle. None of the herbicides increased total forage (alfalfa + weed) yield, and in some instances herbicides reduced forage quality by causing a shift from a palatable to an unpalatable weed species. However, it was observed that AC Blue J consistently yielded more than Beaver, and weed biomass was consistently less in the higher-yielding cultivar. AC Blue J was developed primarily for the irrigated area in southern Alberta and for southern British Columbia. Therefore, additional experiments should be conducted to determine which alfalfa cultivars have the greatest ability to compete with weeds in other regions of western Canada. Key words: Alfalfa yield, dandelion, forage quality, weed control

Weed Management in Southeastern Peanut (Arachis hypogaea) with AC 263,222

1996 ◽  
Vol 10 (1) ◽  
pp. 145-152 ◽  
Author(s):  
John S. Richburg ◽  
John W. Wilcut ◽  
Daniel L. Colvin ◽  
Gerald R. Wiley
Keyword(s):  
Weed Control ◽  
Arachis Hypogaea ◽  
Weed Management ◽  
Field Experiments ◽  
Common Ragweed ◽  
Yellow Nutsedge ◽  
Application Rates ◽  
Ac 263,222

Field experiments conducted at four locations in Georgia and two locations in Florida during 1992 and 1993 evaluated AC 263,222 application rates and timings, systems, and mixtures for weed control, peanut injury, and yield. All rates of AC 263,222 applied early POST (EPOST) or POST controlledIpomoeamorningglories and smallflower morningglory at least 90%, and purple and yellow nutsedge at least 81%. Florida beggarweed and sicklepod control generally was highest when metolachlor was applied PPI followed by AC 263,222 applied EPOST at 71 g/ha, AC 263,222 at 27 or 36 g/ha plus bentazon plus paraquat applied POST, or with bentazon plus paraquat applied EPOST followed by AC 263,222 applied POST at 36 or 53 g/ha. Acifluorfen and acifluorfen plus bentazon reduced Florida beggarweed and sicklepod control at several locations when applied in mixture with AC 263,222. Common ragweed and hairy indigo control were 85 to 95% with bentazon plus paraquat applied EPOST followed by AC 263,222 applied POST at 36 or 53 g/ha. Highest peanut yields were obtained with treatments providing high levels of weed control.

scholarly journals The Critical Period for Weed Control (CPWC) in Potato (Solanum tuberosum L.)

2015 ◽  
Vol 43 (2) ◽  
pp. 355-360 ◽  
Author(s):  
Dogan ISIK ◽  
Adem AKCA ◽  
Emine KAYA ALTOP ◽  
Nihat TURSUN ◽  
Husrev MENNAN
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Critical Period ◽  
Field Experiments ◽  
Yield Loss ◽  
Cropping Systems ◽  
Control Period ◽  
Relative Yield ◽  
Yield Data ◽  
Weed Interference

Accurate assessment of crop-weed control period is an essential part for planning an effective weed management for cropping systems. Field experiments were conducted during the seasonal growing periods of potato in 2012 and 2013 in Kayseri, Turkey to assess critical period for weed control (CPWC) in potato. A four parameter log-logistic model was used to assist in monitoring and analysing two sets of related, relative crop yield. Data was obtained during the periods of increased weed interference and as a comparison, during weed-free periods. In both years, the relative yield of potato decreased with a longer period of weed-interference whereas increased with increasing length of weed free period. In 2012, the CPWC ranged from 112 to 1014 GDD (Growing Degree Days) which corresponded to 8 to 66 days after crop emergence (DAE) and between 135-958 GDD (10 to 63 DAE) in the following year based on a 5% acceptable yield loss. Weed-free conditions needed to be established as early as the first week after crop emergence and maintained as late as ten weeks after crop emergence to avoid more than 5% yield loss in the potato. The results suggest that CPWC could well assist potato producers to significantly reduce the expense of their weed management programs as well as improving its efficacy.

Annual weed management in isoxaflutole-resistant soybean using a two-pass weed control strategy

2019 ◽  
Vol 33 (03) ◽  
pp. 411-425
Author(s):  
Andrea Smith ◽  
Nader Soltani ◽  
Allan J. Kaastra ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
...  
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Field Experiments ◽  
High Rate ◽  
Grass Species ◽  
Annual Grass ◽  
Common Lambsquarters ◽  
Control Programs ◽  
The One ◽  
Herbicide Programs

AbstractTransgenic crops are being developed with herbicide resistance traits to expand innovative weed management solutions for crop producers. Soybean with traits that confer resistance to the hydroxyphenylpyruvate dioxygenase herbicide isoxaflutole is under development and will provide a novel herbicide mode of action for weed management in soybean. Ten field experiments were conducted over 2 years (2017 and 2018) on five soil textures with isoxaflutole-resistant soybean to evaluate annual weed control using one- and two-pass herbicide programs. The one-pass weed control programs included isoxaflutole plus metribuzin, applied PRE, at a low rate (52.5 + 210 g ai ha−1), medium rate (79 + 316 g ai ha−1), and high rate (105 + 420 g ai ha−1); and glyphosate applied early postemergence (EPOST) or late postemergence (LPOST). The two-pass weed control programs included isoxaflutole plus metribuzin, applied PRE, followed by glyphosate applied LPOST, and glyphosate applied EPOST followed by LPOST. At 4 weeks after the LPOST application, control of common lambsquarters, pigweed species, common ragweed, and velvetleaf was variable at 25% to 69%, 49% to 86%, and 71% to 95% at the low, medium, and high rates of isoxaflutole plus metribuzin, respectively. Isoxaflutole plus metribuzin at the low, medium, and high rates controlled grass species evaluated (i.e., barnyardgrass, foxtail, crabgrass, and witchgrass) 85% to 97%, 75% to 99%, and 86% to 100%, respectively. All two-pass weed management programs provided 98% to 100% control of all species. Weed control improved as the rate of isoxaflutole plus metribuzin increased. Two-pass programs provided excellent, full-season annual grass and broadleaf weed control in isoxaflutole-resistant soybean.

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