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1
Regehr, David L., and Keith A. Janssen. "Preplant Weed Control in a Ridge-Till Soybean (Glycine max) and Grain Sorghum (Sorghum bicolor) Rotation." Weed Technology 3, no. 4 (December 1989): 621–26. http://dx.doi.org/10.1017/s0890037x00032917.
Full textAbstract:
Research in Kansas from 1983 to 1986 evaluated early preplant (30 to 45 days) and late preplant (10 to 14 days) herbicide treatments for weed control before ridge-till planting in a soybean and sorghum rotation. Control of fall panicum and common lambsquarters at planting time averaged at least 95% for all early preplant and 92% for late preplant treatments. Where no preplant treatment was used, heavy weed growth in spring delayed soil dry-down, which resulted in poor ridge-till planting conditions and reduced plant stands, and ultimately reduced sorghum grain yields by 24% and soybean yields by 12%. Horsenettle population declined significantly, and honeyvine milkweed population increased. Smooth groundcherry populations fluctuated from year to year with no overall change.
2
Devlin, Daniel L., James H. Long, and Larry D. Maddux. "Using Reduced Rates of Postemergence Herbicides in Soybeans (Glycine max)." Weed Technology 5, no. 4 (December 1991): 834–40. http://dx.doi.org/10.1017/s0890037x00033947.
Full textAbstract:
Eight field studies were conducted in soybeans at seven locations in Kansas over a 3-yr period to examine the efficacy of using reduced rates of the herbicides acifluorfen, bentazon, chlorimuron, and tank mixes of acifluorfen and bentazon. POST applications of these herbicides at 1/2X rates at 2 wk after planting (WAP) resulted in broadleaf weed control similar to that obtained from standard treatments of 1X rates applied at 4 WAP at six of seven studies with acifluorfen, bentazon, and acifluorfen plus bentazon and at five of seven studies with chlorimuron. One-quarter rates applied 2 WAP were equivalent to standard treatments for broadleaf weed control in four of seven studies with acifluorfen and chlorimuron, five of seven studies with bentazon, and six of seven studies with acifluorfen plus bentazon. One cultivation at 4 WAP, increased the broadleaf weed control with all herbicide treatments.
3
Sbatella, Gustavo M., Albert T. Adjesiwor, Andrew R. Kniss, Phillip W. Stahlman, Phil Westra, Michael Moechnig, and Robert G. Wilson. "Herbicide options for glyphosate-resistant kochia (Bassia scoparia) management in the Great Plains." Weed Technology 33, no. 5 (June 20, 2019): 658–63. http://dx.doi.org/10.1017/wet.2019.48.
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AbstractKochia is one of the most problematic weeds in the United States. Field studies were conducted in five states (Wyoming, Colorado, Kansas, Nebraska, and South Dakota) over 2 yr (2010 and 2011) to evaluate kochia control with selected herbicides registered in five common crop scenarios: winter wheat, fallow, corn, soybean, and sugar beet to provide insight for diversifying kochia management in crop rotations. Kochia control varied by experimental site such that more variation in kochia control and biomass production was explained by experimental site than herbicide choice within a crop. Kochia control with herbicides currently labeled for use in sugar beet averaged 32% across locations. Kochia control was greatest and most consistent from corn herbicide programs (99%), followed by soybean (96%) and fallow (97%) herbicide programs. Kochia control from wheat herbicide programs was 93%. With respect to the availability of effective herbicide options, glyphosate-resistant kochia control was easiest in corn, soybean, and fallow, followed by wheat; and difficult to manage with herbicides in sugar beet.
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Yadav, Ramawatar, Vipan Kumar, and Prashant Jha. "Herbicide programs to manage glyphosate/dicamba-resistant kochia (Bassia scoparia) in glyphosate/dicamba-resistant soybean." Weed Technology 34, no. 4 (January 13, 2020): 568–74. http://dx.doi.org/10.1017/wet.2020.3.
Full textAbstract:
AbstractEvolution of kochia resistance to glyphosate and dicamba is a concern for growers in the US Great Plains. An increasing use of glyphosate and dicamba with the widespread adoption of glyphosate/dicamba-resistant (GDR) soybean in recent years may warrant greater attention. Long-term stewardship of this new stacked-trait technology will require the implementation of diverse weed control strategies, such as the use of soil-residual herbicides (PRE) aimed at effective control of GDR kochia. Field experiments were conducted in Huntley, MT, in 2017 and 2018, and Hays, KS, in 2018 to determine the effectiveness of various PRE herbicides applied alone or followed by (fb) a POST treatment of glyphosate plus dicamba for controlling GDR kochia in GDR soybean. Among PRE herbicides tested, sulfentrazone provided complete (100%), season-long control of GDR kochia at both sites. In addition, PRE fb POST programs tested in this study brought 71% to 100% control of GDR kochia throughout the season at both sites. Pyroxasulfone applied PRE resulted in 57% to 70% control across sites at 9 to 10 wk after PRE (WAPRE). However, mixing dicamba with pyroxasulfone improved control up to 25% at both sites. Kochia plants surviving pyroxasulfone applied PRE alone produced 2,530 seeds m−2 compared with pyroxasulfone + dicamba (230 seeds m−2) at the Montana site. No differences in soybean grain yields were observed with PRE alone or PRE fb POST treatments at the Montana site; however, dicamba, pyroxasulfone, and pendimethalin + dimethenamid-P applied PRE brought lower grain yield (1,150 kg ha−1) compared to all other tested programs at the Kansas site. In conclusion, effective PRE or PRE fb POST (two-pass) programs tested in this research should be proactively utilized by the growers to manage GDR kochia in GDR soybean.
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Chatham, Laura A., Kevin W. Bradley, Greg R. Kruger, James R. Martin, Micheal D. K. Owen, Dallas E. Peterson, Jugulam Mithila, and Patrick J. Tranel. "A Multistate Study of the Association Between Glyphosate Resistance and EPSPS Gene Amplification in Waterhemp (Amaranthus tuberculatus)." Weed Science 63, no. 3 (September 2015): 569–77. http://dx.doi.org/10.1614/ws-d-14-00149.1.
Full textAbstract:
Waterhemp is an increasingly problematic weed in the U.S. Midwest, having now evolved resistances to herbicides from six different site-of-action groups. Glyphosate-resistant waterhemp in the Midwest is especially concerning given the economic importance of glyphosate in corn and soybean production. Amplification of the target-site gene, 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS) was found to be the mechanism of glyphosate resistance in Palmer amaranth, a species closely related to waterhemp. Here, the relationship between glyphosate resistance and EPSPS gene amplification in waterhemp was investigated. Glyphosate dose response studies were performed at field sites with glyphosate-resistant waterhemp in Illinois, Kansas, Kentucky, Missouri, and Nebraska, and relative EPSPS copy number of survivors was determined via quantitative real-time polymerase chain reaction (qPCR). Waterhemp control increased with increasing glyphosate rate at all locations, but no population was completely controlled even at the highest rate (3,360 g ae ha−1). EPSPS gene amplification was present in plants from four of five locations (Illinois, Kansas, Missouri, and Nebraska) and the proportion of plants with elevated copy number was generally higher in survivors from glyphosate-treated plots than in plants from the untreated control plots. Copy number magnitude varied by site, but an overall trend of increasing copy number with increasing rate was observed in populations with gene amplification, suggesting that waterhemp plants with more EPSPS copies are more resistant. Survivors from the Kentucky population did not have elevated EPSPS copy number. Instead, resistance in this population was attributed to the EPSPS Pro106Ser mutation. Results herein show a quantitative relationship between glyphosate resistance and EPSPS gene amplification in some waterhemp populations, while highlighting that other mechanisms also confer glyphosate resistance in waterhemp.
6
Chhokar, Rajender Singh, and Rajender Singh Balyan. "Competition and control of weeds in soybean." Weed Science 47, no. 1 (February 1999): 107–11. http://dx.doi.org/10.1017/s004317450009072x.
Full textAbstract:
Two field experiments were carried out from 1993 to 1995 to evaluate the critical period of weed control and to develop suitable weed management practices for jungle rice, horse purslane, and cockscomb in soybean. Horse purslane was more competitive during early growth stages (up to 45 days after sowing [DAS]) and cockscomb was more competitive during later growth stages, whereas jungle rice was competitive throughout the growing season. The critical period of weed control was found to be 30 to 45 DAS. Weed-free maintenance up to 45 DAS resulted in a 74% increase in grain yield of soybean over the unweeded control. Keeping soybean weed free for 45 d or allowing weeds to remain in the crop for less than 30 d resulted in no significant yield loss. Sequential application of a reduced rate of soil-applied trifluralin 1.0 kg ha–1(0.67 ×) with postemergence fluazifop 0.75 kg ha–1(0.75 ×) or a reduced rate of soil-applied trifluralin or pendimethalin at 1.0 kg ha–1(0.67 ×) followed by hand hoeing 35 DAS provided better control of a broad spectrum of weeds than a single application of a postemergence herbicide applied at reduced or recommended rates. Integration of reduced rates of soil-applied herbicides with post-emergence herbicides or hand hoeing 35 DAS produced soybean yields similar to the hand-weeded treatment. Compared to the weed-free or integrated weed control, a single application of soil-applied or postemergence herbicide did not control a broad spectrum of weeds and reduced soybean yield.
7
Buhler, Douglas D., and Jeffery L. Gunsolus. "Effect of Date of Preplant Tillage and Planting on Weed Populations and Mechanical Weed Control in Soybean (Glycine max)." Weed Science 44, no. 2 (June 1996): 373–79. http://dx.doi.org/10.1017/s0043174500094029.
Full textAbstract:
Additional information on mechanical weed management systems is needed so producers can develop systems that meet their production and weed control goals without sacrificing profitability. Field research was conducted at Rosemount, MN, in 1989, 1990, and 1991 to determine the effect of preplant tillage and soybean planting date on weed populations and effectiveness of mechanical weed control operations. Delaying soybean planting from mid-May to early-June reduced weed densities and yield losses from weeds. Weed control with a herbicide treatment was not affected by planting date, but control with rotary hoeing and cultivation was often increased by delaying soybean planting. Early-planted soybean usually yielded better following herbicide treatment than mechanical weed control. However, when preplant tillage and planting were delayed, weed densities were reduced and mechanical weed control operations usually resulted in soybean yield similar to the herbicide treatment. While delaying soybean planting reduced weed densities and improved mechanical weed control, there is potential for reduced soybean yields with delayed planting.
8
Barnes, Jeff W., and Lawrence R. Oliver. "Preemergence Weed Control in Soybean with Cloransulam." Weed Technology 18, no. 4 (December 2004): 1077–90. http://dx.doi.org/10.1614/wt-03-254r1.
Full textAbstract:
Field experiments were conducted from 1999 to 2001 to evaluate preemergence (PRE) activity of cloransulam on broadleaf weed species and to determine the effectiveness of cloransulam as a PRE herbicide in glyphosate-resistant soybean weed management systems. Cloransulam PRE controlled prickly sida, velvetleaf, and morningglory species even at reduced rates (recommended rate 36 g ai/ha) but only suppressed growth of Palmer amaranth, hemp sesbania, and sicklepod. Cloransulam applied PRE provided initial control or suppression of most weeds, but late-season control declined appreciably. Adding metribuzin to cloransulam PRE generally improved control of hemp sesbania, Palmer amaranth, annual grasses, and morningglory species, leading to soybean yield increases. Control of weeds was greater on a silt loam soil compared with a silty clay soil. Delayed herbicide activation by rainfall or irrigation reduced control of hemp sesbania and prickly sida and affected efficacy more than soil texture. Single postemergence (POST) applications of glyphosate or fomesafen plus fluazifop-P provided 90% or less control of most weed species. When glyphosate POST or fomesafen plus fluazifop-P POST followed PRE applications of cloransulam or cloransulam plus metribuzin PRE, control of all weeds was generally greater than 85%. The highest soybean yields were recorded from treatments that contained sequential PRE followed by (fb) POST herbicide applications. Composition of weed flora determined the effect of herbicide program on soybean seed yield. No yield benefit was gained from the sequential program when the dominant species was Palmer amaranth, which was controlled by glyphosate. When hemp sesbania was the dominant species, PRE herbicides fb glyphosate POST increased yield compared with total POST glyphosate.
9
Swanton, Kevin Chandler, Anil Shrestha, and. "Weed seed return as influenced by the critical weed-free period and row spacing of no-till glyphosate-resistant soybean." Canadian Journal of Plant Science 81, no. 4 (October 1, 2001): 877–80. http://dx.doi.org/10.4141/p01-049.
Full textAbstract:
Seed return from later-emerging weeds is a concern in soybean management systems based on critical periods for weed control. This study in Ontario estimated the weed seed return to the soil surface as influenced by the duration of weed control in soybean and soybean row spacing. Weeds emerging after the 1- to 2-trifoliate stage of soybean development did not increase the weed seedbank population compared to the residual population in the weed-free control. Weed seed return was greater in 76 cm than in 38 cm or 19 cm (twin rows) soybean row spacings. Key words: Seedbank, weed population dynamics, integrated weed management, glyphosate-resistant soybean, [Glycine max (L.) Merr].
10
Belfry, Kimberly D., Kristen E. McNaughton, and Peter H. Sikkema. "Weed control in soybean using pyroxasulfone and sulfentrazone." Canadian Journal of Plant Science 95, no. 6 (November 2015): 1199–204. http://dx.doi.org/10.4141/cjps-2015-114.
Full textAbstract:
Belfry, K. D., McNaughton, K. E. and Sikkema, P. H. 2015. Weed control in soybean using pyroxasulfone and sulfentrazone. Can. J. Plant Sci. 95: 1199–1204. Pyroxasulfone and sulfentrazone are new herbicides currently being evaluated for weed control in soybean [Glycine max (L.) Merr.] in Ontario, Canada. Seven experiments were conducted over a 3-yr period (2011 to 2013) at Ridgetown and Exeter, Ontario, to evaluate weed management using pyroxasulfone, sulfentrazone and their tank-mixes relative to the industry standard, imazethapyr plus metribuzin. Tank-mixing pyroxasulfone and sulfentrazone provided up to 97, 46, 60, 100 and 71% control of common lambsquarters (Chenopodium album L.), common ragweed (Ambrosia artemisiifolia L.), green foxtail [Setaria viridis (L.) Beauv.], Powell amaranth [Amaranthus powellii (S.) Wats.] and velvetleaf (Abutilon theophrasti Medic.), respectively, at 2 wk after treatment. Control with pyroxasulfone and sulfentrazone was improved when tank-mixed, relative to application of each herbicide separately. Although control was variable across weed species, no difference in control was identified between pyroxasulfone plus sulfentrazone and imazethapyr plus metribuzin. Soybean yield was up to 2.7, 2.4 and 2.9 t ha−1 for pyroxasulfone, sulfentrazone and pyroxasulfone plus sulfentrazone application, yet imazethapyr plus metribuzin provided the highest yield (3.3 t ha−1). This research demonstrates that pyroxasulfone plus sulfentrazone may be used as a valuable weed control option in soybean; however, weed community composition may limit herbicidal utility.
11
Silvernail, Anthony, and Michael K. Bomford. "(157) Weed Control in Organic Edamame Soybean Production." HortScience 41, no. 4 (July 2006): 1031D—1031. http://dx.doi.org/10.21273/hortsci.41.4.1031d.
Full textAbstract:
Weed control is a major challenge confronting growers transitioning to organic vegetable production. Organic standards require that growers manage weeds without synthetic herbicides while maintaining or enhancing soil quality. In 2005, we evaluated the effects of two seedbed preparation methods and six weed management tactics, compatible with organic standards, on soil quality indicators, weed pressure, and yield of edamame soybean [Glycine max (L.) Merrill]. Seedbed preparation was conducted with either a moldboard plow and roto-tiller or a spading machine. Weeds were managed by a) regular hand weeding, b) pre-emergent flaming, c) post-emergent incorporation of 100 g of corn gluten meal/m2, or weekly passes from crop emergence until row closure with d) a spring-tine weeder, e) a rolling cultivator, or f) a between-row flame weeder. Dominant weeds were smooth pigweed [Amaranthus hybridus (L.)], goosegrass [Eleusine indica (L.) Gaertn.], and giant crabgrass [Digitaria sanguinalis (L.) Scop.]. Smooth pigweed dominated in the corn gluten meal and spring-tine weeder treatments; goosegrass and giant crabgrass dominated in the two flamed treatments. Weed pressure was lowest, and crop yield highest, in the hand-weeded control and rolling cultivator treatments. Relative to these, crop yield was severely depressed by weed pressure in other treatments. The labile carbon concentration and enzymatic activity of soils was tested midseason, and at harvest, showed no significant treatment effects. Results suggest that the rolling cultivator offered the best weed control among the tactics tested, without adversely affecting soil quality.
12
Peterson, Dallas E. "The Impact of Herbicide-Resistant Weeds on Kansas Agriculture." Weed Technology 13, no. 3 (September 1999): 632–35. http://dx.doi.org/10.1017/s0890037x00046315.
Full textAbstract:
Herbicides are important components of weed management programs for most Kansas farmers. Monocropping systems and repeated use of the same or similar herbicides in some areas of the state have resulted in the development of herbicide-resistant weeds. The development of herbicide-resistant weed populations can have an immediate and a long-term effect on the cost, implementation, and effectiveness of weed control programs. In Kansas, resistance to triazine herbicides has been confirmed in kochia (Kochia scoparia), redroot pigweed, common waterhemp (Amaranthus rudis), Palmer amaranth (Amaranthus palmeri), and downy brome (Bromus tectorum) populations, and resistance to acetolactate synthase (ALS)-inhibiting herbicides has been confirmed in kochia, Russian thistle (Salsola kali), common waterhemp, Palmer amaranth, common cocklebur (Xanthium strumarium), shattercane (Sorghum bicolor), and common sunflower (Helianthus annum). The frequency and distribution of herbicide resistance varies among species. Producers who experience herbicide resistance problems adjust their weed control program accordingly. Producers that have not encountered an herbicide resistance problem tend to continue with a successful herbicide program until it fails. The recommended management strategies for herbicide-resistant weed populations include an integrated system of crop rotation, rotation of herbicide modes of action, tank-mixes of herbicides with different modes of action, and cultivation. The greatest direct cost to the producer occurs during the first year of poor weed control. The first response to an herbicide failure often is to reapply the same herbicide that has worked well previously. By the time the producer realizes that the treatment is not going to work, it usually is too late for any other remedial action. Consequently, the farmer experiences reduced crop production from weed competition, high herbicide costs, and a tremendous increase in the seed bank. The increase in seed bank may cost the farmer the most in the long run because the increased weed pressure often requires an intensified control program for several years.
13
Belfry, Kimberly D., Michael J. Cowbrough, François J. Tardif, and Peter H. Sikkema. "Weed management options for conventional soybean." Canadian Journal of Plant Science 96, no. 5 (October 1, 2016): 743–47. http://dx.doi.org/10.1139/cjps-2015-0353.
Full textAbstract:
Various preemergence (PRE), PRE followed by postemergence (POST), and POST weed control options for conventional soybean were evaluated. More than 90% control of selected weed species were observed for most treatments. However, weed interference in plots treated with S-metolachlor + metribuzin or S-metolachlor + metribuzin + cloransulam-methyl resulted in reduced soybean yield.
14
Cantwell, John R., Rex A. Liebl, and Fred W. Slife. "Imazethapyr for Weed Control in Soybean (Glycine max)." Weed Technology 3, no. 4 (December 1989): 596–601. http://dx.doi.org/10.1017/s0890037x00032875.
Full textAbstract:
Imazethapyr at 0.05 to 0.14 kg ai/ha applied preplant incorporated, preemergence, and postemergence was evaluated alone and with complementary herbicides in the field for weed control in soybean. Imazethapyr controlled 90% or more smooth pigweed regardless of application method or herbicide rate. Imazethapyr at 0.05 kg/ha controlled jimsonweed 30% better postemergence compared to soil applications. Imazethapyr at 0.10 kg/ha controlled 90% or more velvetleaf regardless of application method. The addition of alachlor to soil-applied imazethapyr enhanced giant foxtail, jimsonweed, and velvetleaf control. Adding acifluorfen or bentazon to postemergence imazethapyr antagonized weed control. Adding sethoxydim to postemergence imazethapyr was not beneficial.
15
Krausz, Ronald F., George Kapusta, and Joseph L. Matthews. "Sulfentrazone for Weed Control in Soybean (Glycine max)." Weed Technology 12, no. 4 (December 1998): 684–89. http://dx.doi.org/10.1017/s0890037x00044559.
Full textAbstract:
Field studies were conducted over 4 yr to evaluate weed control and soybean injury with sulfentrazone applied preplant incorporated or preemergence alone and in combination with imazaquin, metribuzin, or cloransulam. Sulfentrazone at 280 g ai/ha controlled yellow nutsedge, common waterhemp, ivyleaf morningglory, and velvetleaf 92 to 100% 56 days after planting (DAP). At 420 g/ha, sulfentrazone controlled giant foxtail 80 to 94% 21 DAP. Sulfentrazone controlled common ragweed 17 to 93% and common cocklebur 57 to 91%. Giant foxtail, common cocklebur, and common ragweed control with sulfentrazone at lower rates was improved with the addition of metribuzin or cloransulam. Sulfentrazone caused no visual soybean injury and did not reduce yield compared with standard herbicides.
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Lueschen, William E., and Thomas R. Hoverstad. "Imazethapyr for Weed Control in No-Till Soybean (Glycine max)." Weed Technology 5, no. 4 (December 1991): 845–51. http://dx.doi.org/10.1017/s0890037x00033960.
Full textAbstract:
Lack of consistent weed control has been a major limiting factor in the adoption of no-till soybean production. Field studies were conducted at Waseca, MN from 1987 through 1990 to evaluate the efficacy of imazethapyr applied either alone or in combination with other herbicides for weed control in no-till soybean. Fall applications of imazethapyr did not provide acceptable weed control. Imazethapyr applied 2 to 4 wk before planting provided a weed-free seedbed whereas burndown treatments applied 1 to 3 d before planting failed to do so. Early preplant imazethapyr applied during the second week of April did not control weeds as well as imazethapyr applied during the last week of April. Imazethapyr applied alone PRE failed to control weeds adequately. A split application of early preplant plus PRE imazethapyr resulted in excellent weed control, especially when metribuzin was added with each application. Imazethapyr is a promising herbicide for weed control in no-till soybean production.
17
Place, George T., Samuel Chris Reberg-Horton, Jim E. Dunphy, and Adam N. Smith. "Seeding Rate Effects on Weed Control and Yield For Organic Soybean Production." Weed Technology 23, no. 4 (December 2009): 497–502. http://dx.doi.org/10.1614/wt-08-134.1.
Full textAbstract:
The organic grain sector is one of the fastest growing sectors of the organic market, but farmers in the mid-Atlantic cannot meet the organic grain demand, including the demand for organic soybean. Weed management is cited by farmers as the largest challenge to organic soybean production. Recent soybean population studies show that lower seeding rates for genetically modified organism soybean farmers provide maximum economic return due to high seed technology fees and inexpensive herbicides. Such economic analysis may not be appropriate for organic soybean producers due to the absence of seed technology fees, stronger weed pressures, and price premiums for organic soybean. Soybean seeding rates in North Carolina have traditionally been suggested at approximately 247,000 live seeds/ha, depending on planting conditions. Higher seeding rates may result in a more competitive soybean population and better economic returns for organic soybean producers. Experiments were conducted in 2006 and 2007 to investigate seeding rates of 185,000, 309,000, 432,000, and 556,000 live seeds/ha. All rates were planted on 76-cm row spacing in organic and conventional weed management systems. Increased soybean seeding rates reduced weed ratings at three of the five sites. Increased soybean seeding rates also resulted in higher yield at three of the four sites. Maximum economic returns for organic treatments were achieved with the highest seeding rate in all sites. Results suggest that seeding rates as high as 556,000 live seeds/ha may provide organic soybean producers with better weed control, higher yield, and increased profits.
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Green-Tracewicz, Emily, Eric R. Page, and Clarence J. Swanton. "Light Quality and the Critical Period for Weed Control in Soybean." Weed Science 60, no. 1 (March 2012): 86–91. http://dx.doi.org/10.1614/ws-d-11-00072.1.
Full textAbstract:
The critical period for weed control (CPWC) is an integral component of integrated weed management strategies. Several studies have defined the CPWC in soybean under varying agronomic conditions, yet none have described the mechanisms involved in crop yield losses caused by weed competition. We hypothesized that under nonresource-limiting conditions, morphological changes resulting from the expression of shade avoidance could be used to define a period of developmental sensitivity to low red-to-far-red ratio (R : FR) that would overlap with the defined CPWC in soybean. Two experiments (a sequential harvest and a weed addition/removal series) were conducted in 2008 and 2009 under controlled environmental conditions to address this hypothesis. Two light-quality treatments were used: (1) high R : FR ratio (i.e., weed-free), and (2) low R : FR ratio (i.e., weedy). The low R : FR ratio treatment induced shade avoidance responses in soybean, which included increases in height, internode length, and the shoot : root ratio, as well as a reduction in biomass accumulation and leaf number. Using the morphological changes in biomass and leaf number observed in the weed addition/removal series, a period of developmental sensitivity to low R : FR was defined between the first trifoliate (V1) and third trifoliate (V3) stages of soybean development. This period was found to be very similar to the CPWC previously defined by field studies of soybean–weed competition.
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Webber, Charles L., Harold D. Kerr, and Maurice R. Gebhardt. "Interrelations of Tillage and Weed Control for Soybean (Glycine max) Production." Weed Science 35, no. 6 (November 1987): 830–36. http://dx.doi.org/10.1017/s004317450007942x.
Full textAbstract:
A 3-yr (1982, 1983, and 1984) study was conducted to determine the relationship between tillage and six weed control treatments for soybean [Glycine max(L.) Merr. ‘Williams 79′] production on silt loam (Udollic and Mollic Ochraqualfs). Conventional tillage consisted of spring moldboard plowing and secondary tillage with a combination tool just before planting. No-tillage consisted of a foliar application of glyphosate [N-(phosphonomethyl)glycine] at the time of planting. Weed control treatments included combinations of no weed control with and without soybean plants, preemergence herbicide application only, postemergence herbicide application only, and combined preemergence and postemergence applications with and without additional handweeding. In 1982, a year of above-normal seasonal rainfall, conventional tillage had significantly greater soybean grain yields than no-tillage for all weed control treatments except the preemergence-only treatment. Yields within tillage systems and between weed control treatments in 1982 were not significantly different because adequate rainfall reduced the effect of weed competition for soil moisture. Soybean seed yields in 1983 and 1984 in no-tillage were equal to or significantly greater than those of conventional tillage. No-tillage treatments had greater soil moisture conservation and soil moisture availability resulting in less plant water stress during podfilling in periods of drought in 1983 and 1984. In all 3 yr, conventional tillage had significantly greater early weed growth than no-tillage in the treatments with and without soybean plants where no preemergence or postemergence herbicides were used. Comparing treatments with and without soybean plants indicated an average increase of 36 and 38% weed control for no-tillage and conventional tillage, respectively.
20
Roncatto, Eduardo, Arthur Arrobas Martins Barroso, Juliana Calegarim, Felipe Ridolfo Lucio, and Paulo Fernando Adami. "Control period and economic threshold level of glyphosate tolerant weeds in 2.4-D resistant soybean." Australian Journal of Crop Science, no. 15(02):2021 (February 3, 2021): 297–304. http://dx.doi.org/10.21475/ajcs.21.15.02.p3085.
Full textAbstract:
Weed densities, species, costs of control, crop value and interference periods should be considered for weed management. With this regard, three experiments were carried out to evaluate weed control periods and weed density in a new soybean cultivar. In ths first trial, control efficacy was measured by visual phytotoxicity of four weed species I. hederifolia, E. heterophylla, Conyza spp. and R. brasiliensis using four different herbicides with two doses each: glyphosate (720 and 1,440 g ea ha-1), 2.4-D (670 and 1,340 g ea ha-1), glufosinate (400 and 600 g ea ha-1) and glyphosate + 2.4-D (410 + 390 and 820 + 780 g ea ha-1). Herbicides were sprayed in an entirely randomized 4x8+1 factorial scheme with six repetitions. In the second experiment, 2,4-D-resistant soybean growth was measured under increasing densities of the same weeds (21 plants m² vs 21, 42, 84, 168 and 336 plants m²). This experiment was conducted under entirely randomized design with 25 treatments with four repetitions. Critical level of damage and economic threshold level of each weed species in soybean were measured using non-linear regressions. In a third experiment, weed with soybean were submitted to increasing periods of control and coexistence (7, 14, 21, 28, 35, 49 and 70 days after soybean emergence, plus two control treatments). Glufosinate and glyphosate+2.4-D (820 + 780 g ea ha-1) showed greater weed control than glyphosate alone (720 g ea ha-1). The yield loss of 0.85, 2.12, 5.71 and 34.24% were found for each weed of E. heterophylla, I. hederifolia, R. brasiliensis and Conyza spp., coexisting with soybean. There was a soybean grain yield loss of 50% in the weedy treatment. Soybean weed management should occur between 18thand 48th days after its emergence. Economic threshold level on soybean yield suggested is below one plant of Conyza spp. and R. brasiliensis per m-². The use of glufosinate and glyphosate+2,4-D provides a greater flexibility of herbicide use for farmers
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Buhler, Douglas D., Robert P. King, Scott M. Swinton, Jeffery L. Gunsolus, and Frank Forcella. "Field evaluation of a bioeconomic model for weed management in soybean (Glycine max)." Weed Science 45, no. 1 (February 1997): 158–65. http://dx.doi.org/10.1017/s0043174500092626.
Full textAbstract:
A bioeconomic model was tested as a decision aid for weed control in soybean at Rosemount, MN, from 1991 to 1994. The model makes recommendations for preplant incorporated and preemergence control tactics based on the weed seed content of the soil and postemergence decisions based on weed seedling densities. Weed control, soybean yield, herbicide use, and economic return with model-generated treatments were compared to standard herbicide and mechanical control systems. Effects of these treatments on weed populations and corn yield the following year were also determined. In most cases, the model-generated treatments controlled weeds as well as a standard herbicide treatment. Averaged over the 3 yr, the quantity of herbicide active ingredient applied was decreased by 47% with the seedbank model and 93% with the seedling model compared with a standard soil-applied herbicide treatment. However, the frequency of herbicide application was not reduced. Soybean yields reflected differences in weed control and crop injury. Net economic return to weed control was increased 50% of the time using model-recommended treatments compared with a standard herbicide treatment. Weed control treatments the previous year affected weed density in the following corn crop but had little effect on weed control or corn yield. The bioeconomic model was responsive to differing weed populations, maintained weed control and soybean yield and often increased economic returns under the weed species and densities in this research.
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Ateh, Comfort M., and Jerry D. Doll. "Spring-Planted Winter Rye (Secale cereale) as a Living Mulch to Control Weeds in Soybean (Glycine max)." Weed Technology 10, no. 2 (June 1996): 347–53. http://dx.doi.org/10.1017/s0890037x00040070.
Full textAbstract:
The effects of rye planting time, rye seeding rate, and rye/weed management systems on weed control and soybean yield were determined in field experiments near Arlington, WI from 1992 to 1994. Insufficient precipitation in 1992 resulted in limited soil moisture, less ground cover, less weed control, and lower soybean yields than in 1993 and 1994. The higher rye seeding rate provided more ground cover and better weed control than the lower rate in all years; however, it reduced soybean vigor. The optimum rye seeding rate was 112 kg/ha. The rye-only system reduced weed shoot biomass by 90, 82, and 60%, in 1992, 1993, and 1994, respectively, relative to the no-rye weedy check treatment. Killing rye 45 d after planting soybean gave optimum weed control. In 1993, rye alone suppressed the weeds without decreasing crop yield, but in 1994 crop yield was decreased due to inadequate weed control by rye. The results indicate that the rye living mulch technique can adequately control weeds without causing soybean yield reduction if weed pressure is low, ground cover and soil moisture are adequate and rye interference is minimal.
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Heatherly, Larry G., and C. Dennis Elmore. "Grass Weed Control for Soybean (Glycine max) on Clay Soil." Weed Technology 5, no. 1 (March 1991): 103–7. http://dx.doi.org/10.1017/s0890037x00033340.
Full textAbstract:
Field studies were conducted for four consecutive years to determine if repeated applications of trifluralin (preplant incorporated), metolachlor (preemergence), and fluazifop (postemergence) herbicides alone or combined could be utilized in soybean to effectively control grass weed populations and maintain optimum yield in an irrigated environment where metribuzin plus dinoseb (preemergence) and 2,4-DB plus linuron (postemergence) were used as a standard weed control system. After repeated applications each year, all treatments maintained similar yields that were no different from yields obtained from the standard system. Grass weed infestation did not increase significantly in the treatment that received only the standard weed control herbicides over the duration of the study.
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Swanton, Clarence J., Tony J. Vyn, Kevin Chandler, and Anil Shrestha. "Weed Management Strategies for No-Till Soybean (Glycine max) Grown on Clay Soils." Weed Technology 12, no. 4 (December 1998): 660–69. http://dx.doi.org/10.1017/s0890037x00044523.
Full textAbstract:
Weed management strategies are needed for no-till soybean grown on clay soils. The effect of several weed management strategies on weed biomass, soybean yield, and gross return were evaluated in 1993, 1994, and 1995 on clay soils at two locations in southern Ontario. Soybean seeds were planted in narrow (19 cm) and wide (76 cm) rows with or without a rye cover crop. Herbicide treatments included glyphosate alone, glyphosate followed by imazethapyr + metribuzin applied PRE, and glyphosate followed by acifluorfen + bentazon applied POST. Two additional treatments with interrow cultivation were included in the wide-row soybean plots with glyphosate and glyphosate + PRE treatments. A nontreated check plot without rye was also included. Presence of a cover crop did not affect weed biomass or soybean yield. The glyphosate + broadcast PRE treatment provided the most consistent weed control both in narrow- and wide-row soybean. The weed control in this treatment ranged from 92 to 100%. The other treatments provided variable weed control across years and locations. The narrow- row plots with glyphosate + broadcast PRE treatment provided the most consistent soybean yields that were generally higher than the other treatments and ranged from 2,560 to 3,420 kg/ha. Soybean yields varied across locations and years in other treatments. Similar weed control and soybean yields were obtained with banded PRE herbicide + interrow cultivation and PRE treatments; however, herbicide use was 60% lower in banded PRE herbicide + interrow cultivation treatment. Narrow-row soybean averaged 27% higher gross returns than wide-row soybean for all broadcast herbicide treatments. Narrow-row soybean with PRE herbicide provided the highest gross returns. No-till soybean in narrow rows with preplant glyphosate and broadcast PRE treatment was the most risk-efficient weed management system on clay soils.
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Dieleman, Anita, Allan S. Hamill, Glenn C. Fox, and Clarence J. Swanton. "Decision Rules for Postemergence Control of Pigweed (Amaranthusspp.) in Soybean (Glycine max)." Weed Science 44, no. 1 (March 1996): 126–32. http://dx.doi.org/10.1017/s0043174500093656.
Full textAbstract:
Weed control decision rules were derived for the application of postemergence herbicides to control pigweed species in soybean. Field experiments were conducted at two locations in 1992 and 1993 to evaluate soybean-pigweed interference. A damage function was determined that related yield loss to time of pigweed emergence, density, and soybean weed-free yield. A control function described pigweed species response to variable doses of imazethapyr and thifensulfuron. The integration of these two functions formed the basis of an economic model used to derive two weed control decision rules, the biologist's “threshold weed density” and the economist's “optimal dose.” Time of weed emergence had a more significant role than weed density in the economic model. Later-emerging pigweed caused less yield loss and therefore, decision rules lead to overuse of herbicides if emergence time is not considered. The selected herbicide dose influenced the outcome of the control function. Depending on the desired level of weed control, a herbicide could be chosen to either eradicate the escaped weed species (label or biologically-effective doses) or reduce the growth of the weed species and thereby offset interference (optimal dose). The development of a biologically-effective dose by weed species matrix was recommended. Decision rules should not be utilized as an exclusive weed management strategy but rather as a component of an integrated weed management program.
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Daramola, Olumide Samuel, Olusegun Raphael Adeyemi, Joseph Aremu Adigun, and Christopher Olu Adejuyigbe. "Row spacing and weed management methods influences growth and yield of soybean (Glycine max (L.) Merr.)." Agricultura Tropica et Subtropica 52, no. 2 (June 1, 2019): 59–71. http://dx.doi.org/10.2478/ats-2019-0007.
Full textAbstract:
Abstract Weed infestation is among the primary reasons for low yields of soybean in Nigeria and other parts of Sub Saharan Africa (SSA). Field trials were therefore carried out in 2016 and 2017 cropping seasons to evaluate the effect of row spacing and weed management methods on growth and yield of soybean. The use of 50 cm row spacing resulted in significant (P < 0.05) reduction in weed cover score, weed density and weed dry matter with subsequent increase in soybean growth and grain yield compared to 75 and 100 cm row spacings in both years. In addition, early weed control with probaben at 2.0 kg a.i (active ingredient) ha1 followed by (fb) supplementary hoe weeding (shw) at 6 weeks after sowing (WAS) suppressed weeds and increased soybean growth, which carried through to final dry matter and yield. Pre-emergence application of Probaben fb shw at 6 WAS gave the best weed control and resulted in significantly (P < 0.05) higher soybean grain yield compared to two and three hoe weedings or sole application of probaben under 50 and 75 cm inter-row spacing. However, three hoe weedings gave the best weed control and grain yield under 100 cm inter-row spacing. These results suggest that narrow row spacing of 50 cm and weed control by pre-emergence application of probaben fb shw will improve the productivity of soybean. Wide row spacing, however, required longer weed-free period and consequently multiple hoe weeding for optimum soybean yield.
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Simic, Milena, Nebojsa Momirovic, Zeljko Dolijanovic, and Zeljko Radosevic. "Weed control and grain yield in double-cropped soybean." Pesticidi i fitomedicina 23, no. 2 (2008): 107–14. http://dx.doi.org/10.2298/pif0802107s.
Full textAbstract:
The effects of different herbicide combinations: control (1), alachlor+linuron (2), and alachlor+linuron+imazethapyr (3) were investigated in double-cropped soybean grown in two row spacing variants, 38 cm and 76 cm, under conventional tillage (CT) or no-tillage (NT). In trials conducted on a sandy loam soil at Zemun Polje, high weediness had a negative effect of on the yield of double-cropped soybean, especially at the higher row spacing tested and with no-tillage. Regression and correlation data revealed a dependence of weediness in double-cropped soybean on tillage system and herbicide combination, and dependence of soybean yield on tillage system.
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Elmore, C. Dennis, Larry G. Heatherly, and Richard A. Wesley. "Weed Control in No-till Doublecrop Soybean (Glycine max) Following Winter Wheat (Triticum aestivum) on a Clay Soil." Weed Technology 9, no. 2 (June 1995): 306–15. http://dx.doi.org/10.1017/s0890037x00023393.
Full textAbstract:
Weed control was evaluated in no-till planted soybean in both burned and standing wheat stubble for 3 yr. High, intermediate, low, and no weed management following no-till planting of soybean were compared with a tilled treatment with high weed management. Herbicides for the high weed management were metribuzin plus metolachlor PRE followed by POST applications, as needed, of bentazon, acifluorfen, and fluazifop or quizalofop. Intermediate management included all of the above except metolachlor, plus the as-needed use of chlorimuron or lactofen POST. Low management had no PRE herbicide applications but included the above POST herbicides. Glyphosate was used as a preplant foliar applied desiccant in the stubble-planted soybean of all weed management levels. Yield of soybean was not affected by standing, burned, or tilled wheat stubble. Soil organic matter in the 0 to 2.5 cm of soil was not significantly affected at the end of the 3 yr. Yield of wheat was reduced by standing wheat stubble in the first year of the study. Total POST weed control was sufficient for maximum soybean yields in the second and third years of the study. The weed spectrum changed during the experiment for the no-weed-control treatment in soybean and in wheat. The major weeds present in soybean after 3 yr of no-till were southern crabgrass, nodding spurge, redvine, prickly sida, barnyardgrass, and johnsongrass; in wheat they were Italian ryegrass, little barley, mayweed chamomile, and hairy buttercup.
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Bhowmik, Prasanta C. "Cinmethylin for Weed Control in Soybeans,Glycine max." Weed Science 36, no. 5 (September 1988): 678–82. http://dx.doi.org/10.1017/s0043174500075615.
Full textAbstract:
A 3-yr study was conducted to evaluate efficacy and soybean tolerance of cinmethylin. Cinmethylin was applied preemergence alone at 0.6, 0.8, and 1.0 kg ai/ha or in combination with metribuzin at 0.3 kg/ha. These treatments did not injure soybeans in field trials in 1984, 1985, and 1986. The combination of cinmethylin at 0.7 kg/ha and metribuzin at 0.3 kg/ha controlled more than 90% of large crabgrass, fall panicum, and yellow foxtail. Redroot pigweed and common lambsquarters control was also excellent. Residual control of all grass species was excellent for 8 weeks after preemergence application, followed by reduced control in two of the three grasses. The combination of cinmethylin and metribuzin at 0.7 and 0.3 kg/ha, respectively, significantly increased soybean yields compared to those of untreated plots. These yields were comparable with those obtained from the combination of alachlor and metribuzin at 2.0 and 0.3 kg/ha, respectively. Cinmethylin treatments had no adverse effects on soybean yield components including pods/plant, seed/pod, and seed weight. Cinmethylin shows potential as a preemergence herbicide for full-season weed control in soybean production.
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Steckel, Lawrence E., Michael S. Defelice, and Barry D. Sims. "Integrating Reduced Rates of Postemergence Herbicides and Cultivation for Broadleaf Weed Control in Soybeans (Glycine max)." Weed Science 38, no. 6 (November 1990): 541–45. http://dx.doi.org/10.1017/s0043174500051456.
Full textAbstract:
The interaction of reduced rates of bentazon, chlorimuron, imazaquin, and imazethapyr with cultivation for broadleaf weed control in soybeans was investigated in field experiments conducted at three sites in Missouri in 1987 and 1988. Single reduced-rate herbicide applications provided soybean yields equal to full rates although visual weed control was slightly lower. Sequential applications of all four herbicides at reduced rates provided weed control and soybean yields equal to full-rate applications. The number of velvetleaf plants m−2and seeds plant−1were not influenced by herbicide, herbicide rate, or application timing. Cultivation improved weed control and soybean yield and decreased late-season weed populations and seed production.
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Van Acker, Rene C., Clarence J. Swanton, and Stephan F. Weise. "The Critical Period of Weed Control in Soybean [Glycine max(L.) Merr.]." Weed Science 41, no. 2 (June 1993): 194–200. http://dx.doi.org/10.1017/s0043174500076050.
Full textAbstract:
Field studies were conducted at three locations over 2 yr in southern Ontario to determine the critical period of weed control in soybean. This period generally consisted of two discrete periods, a critical weed-free period and a critical time of weed removal. The critical weed-free period was relatively short in duration and consistent across locations and years. A period of weed control lasting up to the fourth node growth stage (V4), approximately 30 days after emergence (DAE), was adequate to prevent a yield loss of more than 2.5%. The critical time of weed removal was variable across locations and years and ranged, for example, from the second node growth stage (V2) to the beginning pod growth stage (R3), approximately 9 to 38 DAE, at a 2.5% yield loss level. A phenologically based period of most rapid yield loss due to weed interference occurred from beginning bloom stage (R1) to beginning seed stage (R5). The short and consistent critical weed-free period indicates the duration of residual herbicide control necessary in soybean and supports use of nonresidual, postemergence herbicides and mechanical weed control.
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Place, George T., S. Chris Reberg-Horton, and Michael G. Burton. "Effects of Preplant and Postplant Rotary Hoe Use on Weed Control, Soybean Pod Position, and Soybean Yield." Weed Science 57, no. 3 (June 2009): 290–95. http://dx.doi.org/10.1614/ws-08-132.1.
Full textAbstract:
Demand for organic food products has consistently increased for more than 20 yr. The largest obstacle to organic soybean production in the southeastern United States is weed management. Current organic soybean production relies on mechanical weed control, including multiple postplant rotary hoe uses. Although postplant rotary hoe use is effective at the weed germination stage, its efficacy is severely compromised by delays due to weather. Preplant rotary hoeing is also a practice that has been utilized for weed control but the effectiveness of this practice to reduce the need for multiple postplant rotary hoeing for organic soybean production in the southeastern United States has not been investigated. Preplant rotary hoe treatments included a weekly rotary hoeing 4 wk before planting, 2 wk before planting, and none. Postplant rotary hoe treatments consisted of zero, one, two, three, and four postplant rotary hoe uses. Weed control was increased with preplant rotary hoeing at Plymouth in 2006 and 2007 but this effect disappeared with the first postplant rotary hoeing. Multiple postplant rotary hoe uses decreased soybean plant populations, decreased soybean canopy height, lowered soybean pod position, and decreased soybean yield. Plant mapping revealed that the percentage of total nodes and pods below 30 cm was increased by increased frequency of postplant rotary hoe use.
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Buhler, Douglas D., and Virginia L. Werling. "Weed Control from Imazaquin and Metolachlor in No-till Soybeans (Glycine max)." Weed Science 37, no. 3 (May 1989): 392–99. http://dx.doi.org/10.1017/s0043174500072118.
Full textAbstract:
In 1985, when weed densities were low (169 plants/m2in untreated control), imazaquin applied at 0.07 kg ai/ha early preplant controlled over 90% of all weeds before no-till planting of soybeans. In 1986 and 1987 when weed densities were higher (589 plants/m2in untreated control), addition of 1.1 kg ai/ha or more of metolachlor to imazaquin (0.07 kg/ha) before soybean planting controlled 95% or more of the grass weeds and 83% or more of the broadleaf weeds. Imazaquin plus metolachlor applied less than 1 day after soybean planting controlled less than 70% of the emerged weeds in 1986 and 1987; common lambsquarters was most tolerant. Early preplant treatments controlled more weeds throughout the growing season than treatments applied after planting. Splitting herbicide treatments among application times generally did not increase weed control compared to single applications. Early preplant applications resulted in higher soybean densities and taller soybeans 30 days after planting in 1986 and 1987 than treatments applied after planting. Soybean yields increased as weed control increased. Weed control and soybean yields were greater with early preplant treatments than paraquat plus alachlor plus metribuzin applied preemergence in 1986 and 1987. No carryover of imazaquin residue was detected through corn bioassay in the field.
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Vizantinopoulos, Spyros, and Nikos Katranis. "Integrated Weed Control Management in Soybeans (Glycine max) in Greece." Weed Technology 8, no. 3 (September 1994): 541–46. http://dx.doi.org/10.1017/s0890037x00039658.
Full textAbstract:
Field experiments were conducted in 1988, 1989, and 1990 in Greece to investigate the combination of cultural and chemical methods for weed control in soybean. The selectivity of herbicides or the combination of herbicides used was dependent on application rate. Imazaquin applied PRE was selective on soybean even at 0.18 kg/ha, whereas imazethapyr was safer on soybean than imazaquin at 0.22 kg/ha. Metribuzin at 0.37 kg/ha tank-mixed with alachlor, metolachlor, imazaquin, and SAN 582H were not phytotoxic at their recommended rates. All herbicides satisfactorily controlled the weeds in the experiments. The early-season period threshold level for a mixed population ofAmaranthusspp. occurred 3.0 to 3.5 wk after weed emergence. Density ofAmaranthusspp. of about 270 to 470 plants/m2caused soybean yield reduction equal to 11 to 35%, respectively. The treatments did not influence the oil content of the soybean seed but in one experiment the protein content was influenced slightly by some of the treatments. The results emphasize the importance of using chemical, cultural, and competition threshold levels of cultural practices for an integrated approach for weed control in soybean.
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Arce, Guillermo D., Palle Pedersen, and Robert G. Hartzler. "Soybean Seeding Rate Effects on Weed Management." Weed Technology 23, no. 1 (March 2009): 17–22. http://dx.doi.org/10.1614/wt-08-060.1.
Full textAbstract:
Studies were conducted in 2005 and 2006 at three Iowa locations to determine the effect of soybean seeding rate and glyphosate application timing on weed management and grain yields in glyphosate-resistant soybean. End-of-season weed populations were affected by soybean seeding rate at only one location, with higher weed densities present in the lowest seeding rate when glyphosate was applied at the V2 soybean growth stage. Although weed populations were not consistently affected by soybean population, weed biomass present at soybean harvest was inversely related to soybean population. At the location with the highest weed populations, no single glyphosate application provided yields equivalent to the weed-free control. At the other locations, glyphosate application timing did not affect soybean yield. Lower soybean yields occurred with 240,000 seed/ha compared with 420,000 seed/ha at all locations and with 300,000 seed/ha at two locations.
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Smith, Andrea, Nader Soltani, Allan J. Kaastra, David C. Hooker, Darren E. Robinson, and Peter H. Sikkema. "Annual weed management in isoxaflutole-resistant soybean using a two-pass weed control strategy." Weed Technology 33, no. 03 (April 29, 2019): 411–25. http://dx.doi.org/10.1017/wet.2019.21.
Full textAbstract:
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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Jhala, Amit J., Mayank S. Malik, and John B. Willis. "Weed control and crop tolerance of micro-encapsulated acetochlor applied sequentially in glyphosate-resistant soybean." Canadian Journal of Plant Science 95, no. 5 (September 2015): 973–81. http://dx.doi.org/10.4141/cjps-2014-422.
Full textAbstract:
Jhala, A. J., Malik, M. S. and Willis, J. B. 2015. Weed control and crop tolerance of micro-encapsulated acetochlor applied sequentially in glyphosate-resistant soybean. Can. J. Plant Sci. 95: 973–981. Acetochlor, an acetamide herbicide, has been used for many years for weed control in several crops, including soybean. Micro-encapsulated acetochlor has been recently registered for preplant (PP), pre-emergence (PRE), and post-emergence (POST) application in soybean in the United States. Information is not available regarding the sequential application of acetochlor for weed control and soybean tolerance. The objectives of this research were to determine the effect of application timing of micro-encapsulated acetochlor applied in tank-mixture with glyphosate in single or sequential applications for weed control in glyphosate-resistant soybean, and to determine its impact on soybean injury and yields. Field experiments were conducted at Clay Center, Nebraska, in 2012 and 2013, and at Waverly, Nebraska, in 2013. Acetochlor tank-mixed with glyphosate applied alone PP, PRE, or tank-mixed with flumioxazin, fomesafen, or sulfentrazone plus chlorimuron provided 99% control of common waterhemp, green foxtail, and velvetleaf at 15 d after planting (DAP); however, control declined to ≤40% at 100 DAP. Acetochlor tank-mixed with glyphosate applied PRE followed by early POST (V2 to V3 stage of soybean) or late POST (V4 to V5 stage) resulted in ≥90% control of common waterhemp and green foxtail, reduced weed density to ≤2 plants m−2 and biomass to ≤12 g m−2, and resulted in soybean yields >3775 kg ha−1. The sequential applications of glyphosate plus acetochlor applied PP followed by early POST or late POST resulted in equivalent weed control to the best herbicide combinations included in this study and soybean yield equivalent to the weed free control. Injury to soybean was <10% in each of the treatments evaluated. Micro-encapsulated acetochlor can be a good option for soybean growers for controlling grasses and small-seeded broadleaf weeds if applied in a PRE followed by POST herbicide program in tank-mixture with herbicides of other modes of action.
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Soltani, Nader, Lynette R. Brown, and Peter H. Sikkema. "Weed Control in Corn and Soybean with Group 15 (VLCFA Inhibitor) Herbicides Applied Preemergence." International Journal of Agronomy 2019 (April 7, 2019): 1–7. http://dx.doi.org/10.1155/2019/8159671.
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Limited information exists on the efficacy of pethoxamid for annual grass and broadleaf control in corn and soybean in Ontario. A total of 10 field experiments (5 with corn and 5 with soybean) were conducted during 2015 to 2017 in Ontario, Canada, to compare the weed control efficacy of dimethenamid-P at 544 g·ai·ha−1, pethoxamid at 840 g·ai·ha−1, pyroxasulfone at 100 g·ai·ha−1, and S-metolachlor at 1050 g·ai·ha−1 applied preemergence (PRE). Reduced weed interference with pyroxasulfone and dimethenamid-P resulted in corn yield that was similar to the weed-free control; however, weed interference with pethoxamid and S-metolachlor reduced corn yield 28 and 33%, respectively. Reduced weed interference with pyroxasulfone resulted in soybean yield that was similar to the weed-free control; however, weed interference with pethoxamid, dimethenamid-P, and S-metolachlor reduced soybean yield 27, 27, and 30%, respectively. At 4 and 8 weeks after application (WAA), all VLCFA inhibitor herbicides (Group 15) provided excellent redroot pigweed control (90 to 99%) in corn. There were no differences in common ragweed control, density, and dry weight among the VLCFA inhibitor herbicide evaluated; pyroxasulfone provided highest numeric common ragweed control and lowest numeric density and dry weight. At 4 and 8 WAA, pyroxasulfone provided the best common lambsquarters and wild mustard control and lowest numeric density and dry weight in corn and soybean. At 8 WAA, the VLCFA inhibitor herbicides controlled green foxtail 91 to 96% in corn; dimethenamid-P provided better control of green foxtail than pethoxamid in soybean. There were no differences in barnyard grass control among the VLCFA inhibitor herbicides evaluated.
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Song, Jong-Seok, Ji-Hoon Chung, Kyu Jong Lee, Jihyung Kwon, Jin-Won Kim, Ji-Hoon Im, and Do-Soon Kim. "Herbicide-Based Weed Management for Soybean Production in the Far Eastern Region of Russia." Agronomy 10, no. 11 (November 20, 2020): 1823. http://dx.doi.org/10.3390/agronomy10111823.
Full textAbstract:
This study was conducted to establish a weed management system based on the sequential application of pre-emergence (PRE) and post-emergence (POST) herbicides for soybean production in Primorsky krai. Field experiments were conducted for two years in a field located in Bogatyrka, Primorsky krai, Russia (N43°49′, E131°36′). No herbicide application resulted in significant soybean yield loss, 0.03–0.3 t ha−1, which is more than 91.6% yield loss compared with that of the weed-free plot. The PRE application of acetochlor showed good weed control efficacy (greater than 90% weed control) with acceptable soybean safety (less than 10% soybean damage), while the other PRE herbicides performed poorly in terms of weed control. The POST application of bentazon + acifluorfen, bentazon, and imazamox at 30 days after soybean sowing (DAS) showed good weed control efficacy with good soybean safety. Neither the PRE nor POST application alone showed a sufficient soybean yield protection, resulting in much lower soybean yield than the weed-free plot. The sequential application of acetochlor (PRE), followed by either bentazon + acifluorfen (POST) at 30 DAS in 2012 or bentazon + imazamox (POST) at 60 DAS in 2013 showed the best performance in soybean yields, 1.7 t and 1.9 t ha−1, respectively, provided with 724.5 US$ and 1155.6 US$ ha−1 of economic returns. For alternative PRE herbicides of acetochlor, which is now banned, our tests of the sequential application of S-metolachlor with other POST herbicides and the sole application of other PRE herbicides revealed that S-metolachlor and clomazone could also be considered. Our results thus demonstrate that the sequential applications of PRE and POST herbicides should be incorporated into the weed management system for soybean production in Primorsky krai, Russia.
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Watts, Jeffrey R., Edward C. Murdock, Gregory S. Stapleton, and Joe E. Toler. "Sicklepod (Senna obtusifolia) Control in Soybean (Glycine max) with Single and Sequential Herbicide Applications." Weed Technology 11, no. 1 (March 1997): 157–63. http://dx.doi.org/10.1017/s0890037x00041518.
Full textAbstract:
Field studies were conducted in 1991 to 1993 to determine the effects of PRE and POST herbicides alone and in factorial combinations on sicklepod control, weed biomass, and soybean seed yields. Herbicides evaluated were metribuzin PRE, metribuzin + chlorimuron PRE, imazaquin PRE and POST, chlorimuron POST, and AC 263,222 POST POST herbicides alone provided better sicklepod control than PRE herbicides alone. However, sequential (SEQ) treatments [PRE followed by (fb) POST] provided better sicklepod control than single herbicide treatments. Metribuzin and metribuzin + chlorimuron alone or used in a SEQ program provided similar PRE control of sicklepod, and both controlled sicklepod better than imazaquin in 1991 and 1992. Chlorimuron alone or in a SEQ program provided better POST control than AC 263,222 or imazaquin alone when soil moisture levels at planting favored weed seed germination. When soil moisture levels at planting were unfavorable for weed seed germination, the residual activity of imazaquin provided the best season-long control. SEQ herbicide applications allowed soybean to attain higher seed yields than single (PRE or POST) herbicide treatments all 3 yr. However, only metribuzin fb chlorimuron in 1991 and 1992 and imazaquin fb imazaquin and imazaquin fb chlorimuron in 1993 allowed soybean to achieve seed yields similar to weed-free soybean. Soybean seed yields were greater with POST than with PRE herbicides 2 of 3 yr, but no single herbicide treatment provided soybean seed yields similar to weed-free soybean.
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Parmar, Pramendra Singh, Namrata Jain, Devendra, and Ravindra Solanki. "Efficacy of different herbicides for weed control in soybean." Indian Journal of Weed Science 48, no. 4 (2016): 453. http://dx.doi.org/10.5958/0974-8164.2016.00117.9.
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Hart, Stephen E., Loyd M. Wax, and Aaron G. Hager. "Comparison of Total Postemergence Weed Control Programs in Soybean." Journal of Production Agriculture 10, no. 1 (January 1997): 136–41. http://dx.doi.org/10.2134/jpa1997.0136.
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Vidrine, P. Roy, James L. Griffin, David L. Jordan, and Daniel B. Reynolds. "Broadleaf Weed Control in Soybean (Glycine max) with Sulfentrazone." Weed Technology 10, no. 4 (December 1996): 762–65. http://dx.doi.org/10.1017/s0890037x00040781.
Full textAbstract:
Experiments were conducted at three locations in Louisiana from 1992 to 1994 to evaluate broadleaf weed control with sulfentrazone. Sulfentrazone at 0.42 kg ai/ha applied PPI or PRE provided at least 93% control of entireleaf morningglory in all years at all locations, which was greater than control with metribuzin PRE. Prickly sida control with sulfentrazone ranged from 83 to 94%, which was equal to or greater than control with metribuzin. Hemp sesbania and sicklepod control with sulfentrazone was unacceptable (≤75%) regardless of application method and generally was lower than control with metribuzin. Greater than 90% control of smellmelon and hophornbeam copperleaf was observed with all treatments. Minor but transient soybean injury was noted at one location in one year. Soybean yields following sulfentrazone PRE at St. Joseph were greater than yields with metribuzin as a result of the general increase in broadleaf weed control.
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Reddy, Krishna N. "Weed Control and Economic Comparisons in Soybean Planting Systems." Journal of Sustainable Agriculture 21, no. 2 (November 12, 2002): 21–35. http://dx.doi.org/10.1300/j064v21n02_04.
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Wilkerson, G. G., S. A. Modena, and H. D. Coble. "HERB: Decision Model for Postemergence Weed Control in Soybean." Agronomy Journal 83, no. 2 (January 1991): 413–17. http://dx.doi.org/10.2134/agronj1991.00021962008300020030x.
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Kluchinski, Daniel, and Jeremy W. Singer. "Evaluation of Weed Control Strategies in Organic Soybean Production." Crop Management 4, no. 1 (2005): 1–6. http://dx.doi.org/10.1094/cm-2005-0614-01-rs.
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Poston, Daniel H., Vijay K. Nandula, R. Matt Griffin, David R. Shaw, and M. Cade Smith. "Weed Control Alternatives in Very Early-Maturing Mississippi Soybean." Crop Management 6, no. 1 (2007): 1–15. http://dx.doi.org/10.1094/cm-2007-0323-02-rs.
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Silva, Diecson Ruy Orsolin da, Leandro Vargas, Dirceu Agostinetto, and Franciele Mariani. "Glyphosate-resistant hairy fleabane competition in RR® soybean." Bragantia 73, no. 4 (October 28, 2014): 451–57. http://dx.doi.org/10.1590/1678-4499.0200.
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Weed competition in the soybean causes changes in morphological and physiological characteristics that reduce the competitive ability of the crop. The objective of this study was to determine the control periods and coexistence of glyphosate-resistant hairy fleabane and its interference in morphological and photosynthetic variables and RR soybean yield. A field experiment was conducted during the 2011/2012 growing season, the treatments consisted of weed interference and weed free periods of the glyphosate-resistant hairy fleabane with soybean (BRS Estância RR). The periods were 0, 7, 14, 21, 28, 35, 42 and 154 days after the soybean emergence. The results sugested no differences between the control periods for the variables evaluated. The increase interference period of the weed reduced growth, development and the photosynthetic variables in the soybean. There are positive correlations between morphological and photosynthetic variables of soybean during the weed interference. The period before the glyphosate-resistant hairy fleabane interference in the soybean crop is 24 days for plants established before the crop sowing.
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Nelson, Kelly A., Reid J. Smeda, and Randall L. Smoot. "Spring-Interseeded Winter Rye Seeding Rates Influence Weed Control and Organic Soybean Yield." International Journal of Agronomy 2011 (2011): 1–7. http://dx.doi.org/10.1155/2011/571973.
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Field research in 2002 and 2003 evaluated spring-interseeded winter rye (Secale cerealeL.) at 67, 134, or 200 kg ha−1at two soybean (Glycine max(L.) Merr.) row spacings (19- and 76-cm) on weed control, yield, and gross margins. Based on regression analysis, wide-row (76-cm) soybean grain yield and gross margins were greatest when winter rye was interseeded at 114 and 106 kg ha−1, respectively. Yields and gross margins for wide-row soybean were 8 to 55% greater than narrow-row (19-cm) soybean seeded at 494,000 or 742,000 seeds ha−1which was probably due to flexibility for implementing cultivation. As interseeded rye rates increased from 67 to 200 kg ha−1, yields and gross margins for narrow-rows decreased. Soybean row spacing had minimal impacts on specific weed species and total weed biomass or density. The use of wide-row soybean and spring-interseeded rye at 67 kg ha−1was more cost-effective compared to narrow rows.
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Nord, Eric A., Matthew R. Ryan, William S. Curran, David A. Mortensen, and Steven B. Mirsky. "Effects of Management Type and Timing on Weed Suppression in Soybean No-Till Planted into Rolled-Crimped Cereal Rye." Weed Science 60, no. 4 (December 2012): 624–33. http://dx.doi.org/10.1614/ws-d-12-00024.1.
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Knowledge of weed emergence periodicity can inform the timing and choice of weed management tactics. We tested the effects of weed management system (conventional [CNV] and herbicide-free [HF]), timing of rye sowing (two dates), timing of soybean planting (5 planting dates, 3 in each system), and supplemental control (with and without) on weed suppression and weed community composition in soybean no-till planted into a cereal rye cover crop. Cereal rye was terminated with a roller-crimper and herbicide (CNV) or with a roller-crimper alone (HF), and supplemental weed control was achieved with a postemergence glyphosate application (CNV) or with interrow high-residue cultivation (HF). Supplemental control with glyphosate in CNV was more effective than high-residue cultivation in HF. When soybean was planted on the same date, CNV resulted in less weed biomass and a more even community composition, whereas HF resulted in greater weed biomass, dominated by common ragweed. When we controlled for cereal rye biomass and compared the effects of cereal rye sowing and termination timing within each system, earlier management reduced weed biomass in HF, but tended to increase weed biomass in CNV. Our results suggest the ability to control emerged weeds prior to soybean planting is an important factor that influences the optimal cereal rye cover crop management timing for weed suppression.