Broadcast or Banded Chloramben by Tillage Variables in Soybeans

Weed Science ◽  
1972 ◽  
Vol 20 (5) ◽  
pp. 502-506 ◽  
Author(s):  
R. S. Moomaw ◽  
L. R. Robison

The herbicide 3-amino-2,5-dichlorobenzoic acid (chloramben) was applied preemergence to soybeans [Glycine max(L.) Merr.] in 1969, 1970, and 1971. Herbicide band widths were 18, 36, and 53 cm, and there was a broadcast treatment. Cultivation and rotary hoeing were also imposed on the herbicide band widths as variables. A 36-cm band of chloramben was the minimum band width used which consistently maintained soybean yield when supplemented with mechanical tillage. Broadcast treated soybeans without mechanical tillage yielded as well as handweeded soybeans in 2 of 3 years. Each 4 kg/ha of weed growth reduced soybean yield 1 kg/ha. Average weed yield reduction due to cultivation was 100, 76, and 54% in 1969, 1970, and 1971, respectively, when average weed yields were 360, 1650, and 4720 kg/ha in successive years. Rotary hoeing reduced weed growth 48% and increased soybean yield 20% in 1970 but did not significantly affect weed or soybean yields in 1969 and 1971.

Weed Science ◽  
1972 ◽  
Vol 20 (1) ◽  
pp. 16-19 ◽  
Author(s):  
L. M. Wax

Delayed planting or “stale seedbed” for weed control in close-drilled (20-cm rows) soybeans [Glycine max(L.) Merr. ‘Amsoy’] was evaluated for 3 years. The system combined final seedbed preparation 3 to 6 weeks before planting with herbicide application at planting time. The best control of six weed species and highest soybean yields were obtained bya,a,a-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine (trifluralin) application at the time of seedbed preparation followed by 3-(3,4-dichlorophenyl)-1-methylurea (linuron) application at planting and by linuron application at planting without the early trifluralin application. Applications of 1,1′-dimethyl-4,4′-bipyridinium ion (paraquat) at planting, either with or without trifluralin treatments, resulted in less weed control and lower soybean yields than comparable treatments with linuron. However, even the best treatments failed to provide the weed control necessary to prevent substantial soybean yield reduction in heavy infestations of weeds that emerge in large numbers after planting, and that resist the phytotoxic action of the herbicides.


Weed Science ◽  
1992 ◽  
Vol 40 (1) ◽  
pp. 68-73 ◽  
Author(s):  
Gary M. Fellows ◽  
Fred W. Roeth

Shattercane interference in irrigated soybean was evaluated during 1987, 1988, and 1989 at Clay Center, NE, using ‘Rox’ forage sorghum to simulate shattercane. Soybean yield reduction did not occur if shattercane was removed by 2 wk after emergence in 1987 and 6 wk after emergence in 1988 and 1989. Shattercane interference with soybean began when shattercane height exceeded soybean height. Soybean yield was reduced up to 25% before the height differential reached 30 cm, the minimum difference required for selectively applying glyphosate with a wiper applicator. Soybean nodes per stem, pods per stem, and beans per pod decreased as duration of interference increased. A direct relationship between soybean yield loss and shattercane density fit a rectangular hyperbolic function. Yield loss per shattercane plant was highest at low shattercane densities. Soybean plant height, biomass, nodes per stem, pods per stem, pods per node, and beans per pod decreased as shattercane density increased. An interference model for estimation of soybean yield and economic loss based on shattercane density was developed.


Weed Science ◽  
1994 ◽  
Vol 42 (4) ◽  
pp. 523-527 ◽  
Author(s):  
Tracy E. Klingaman ◽  
Lawrence R. Oliver

A 2-yr field study was conducted at Fayetteville, AR, to determine the effect of Palmer amaranth interference on soybean growth and yield. Palmer amaranth density had little effect on soybean height, but soybean canopy width ranged from 77 cm in the weed-free check to 35 cm in plots with 10 plants m–1of row 12 wk after emergence. Soybean yield reduction was highly correlated to Palmer amaranth biomass at 8 wk after emergence and maturity, soybean biomass at 8 wk after emergence, and Palmer amaranth density. Soybean yield reduction was 17, 27, 32, 48, 64, and 68%, respectively, for Palmer amaranth densities of 033, 0.66, 1, 2, 333, and 10 plants m–1of row. Soybean yield reduction and Palmer amaranth biomass were linear to approximately 2 Palmer amaranth m–1of row, suggesting intraspecific interference between adjacent Palmer amaranth is initiated at Palmer amaranth densities between 2 and 3.33 plants m–1of row.


Weed Science ◽  
1984 ◽  
Vol 32 (3) ◽  
pp. 364-370 ◽  
Author(s):  
Ronald C. Cordes ◽  
Thomas T. Bauman

Detrimental effects on growth and yield of soybeans [Glycine max(L.) Merr. ‘Amsoy 77′] from density and duration of competition by ivyleaf morningglory [Ipomea hederacea(L.) Jacq. ♯3IPOHE] was evaluated in 1981 and 1982 near West Lafayette, IN. Ivyleaf morningglory was planted at densities of 1 plant per 90, 60, 30, and 15 cm of row in 1981 and 1 plant per 60, 30, 15, and 7.5 cm of row in 1982. Each density of ivyleaf morningglory competed for 22 to 46 days after emergence and the full season in 1981, and for 29 to 60 days after emergence and the full season in 1982. The best indicators of competition effects were leaf area index, plant dry weight, and yield of soybeans. Ivyleaf morningglory was more competitive during the reproductive stage of soybean growth. Photosynthetic irradiance and soil moisture measurements indicated that ivyleaf morningglory does not effectively compete for light or soil moisture. All densities of ivyleaf morningglory could compete with soybeans for 46 and 60 days after emergence in 1981 and 1982, respectively, without reducing soybean yield. Full-season competition from densities of 1 ivyleaf morningglory plant per 15 cm of row significantly reduced soybean yield by 36% in 1981 and 13% in 1982. The magnitude of soybean growth and yield reduction caused by a given density of ivyleaf morningglory was greater when warm, early season temperatures favored rapid weed development.


1999 ◽  
Vol 13 (2) ◽  
pp. 264-270 ◽  
Author(s):  
Kassim Al-Khatib ◽  
Dallas Peterson

Field research was conducted to evaluate the response of soybean to various herbicides applied at rates to simulate drift damage. Dicamba, glyphosate, glufosinate, and the sulfonylurea herbicides CGA-152005, primisulfuron, nicosulfuron, rimsulfuron plus thifensulfuron, and CGA-152005 plus primisulfuron were applied to soybean at the two to three trifoliolate leaf stage in 1997 and 1998 atand ⅓ of the recommended use rates. The order of yield reduction after herbicide treatment was CGA-152005 > dicamba > CGA-152005 plus primisulfuron > rimsulfuron plus thifensulfuron > primisulfuron. Soybean yields were not reduced by glyphosate, glufosinate, and nicosulfuron. Applications of all herbicides at rates higher thanof the use rate caused injury symptoms within 30 d after treatment. However, soybean plants had partially or fully recovered by the end of the growing season. Therefore, early-season injury symptoms from herbicide drift are not reliable indicators for soybean yield reduction.


1993 ◽  
Vol 7 (1) ◽  
pp. 220-225 ◽  
Author(s):  
Gordon D. Vail ◽  
Lawrence R. Oliver

A 2-yr field experiment was conducted at Fayetteville and Stuttgart, AR, to predict soybean yield loss as a function of barnyardgrass density and total dry weight. Predicted soybean yield reductions were 0 to 78% for original densities of 1 to 500 barnyardgrass plants per m of row. Soybean yield reductions were linear from 0 to 150 barnyardgrass plants per m of row with an average yield reduction of 0.25% for each plant per m of row. Soybean yield was reduced 10, 25, and 50% from original barnyardgrass densities of 42, 110, and 250 plants m of row. Predictions of soybean yield reduction from barnyardgrass dry weight and original density were similar. traspecific interference of barnyardgrass occurred for all variables tested, with individual barnyardgrass plants becoming less competitive as density increased.


Weed Science ◽  
1976 ◽  
Vol 24 (5) ◽  
pp. 482-488 ◽  
Author(s):  
L. R. Oliver ◽  
R. E. Frans ◽  
R. E. Talbert

The intraspecific (competition between same species) and interspecific (competition between different species) competitiveness of tall morningglory [Ipomoea purpurea(L.) Roth] in soybeans [Glycine max(L.) Merr.] was evaluated for 3 yr at Fayetteville, Arkansas. Tall morningglory was planted at densities of one plant per 61, 30, and 15 cm of row, and competition duration ranged from 2 weeks to full-season. Soybeans were more competitive than tall morningglory for the first 6 to 8 weeks after emergence. The competitiveness of tall morningglory was dependent upon a rapid increase in photosynthetic area which occurred 4 to 6 weeks after emergence. Reductions in leaf area index (LAI) or plant dry weight and crop growth rate (CGR) of soybeans were closely correlated to percent soybean yield reduction. Tall morningglory could remain in soybeans for 12, 10, and 6 weeks without significantly reducing soybean yield at one plant per 61, 30, and 15 cm of row, respectively. Tall morningglory was three to four times more competitive during the soybean reproductive stage than during the vegetative stage.


2006 ◽  
Vol 20 (4) ◽  
pp. 1035-1039 ◽  
Author(s):  
Derek M. Scroggs ◽  
Donnie K. Miller ◽  
Paul R. Vidrine ◽  
Robert G. Downer

Field trials were conducted to evaluate weed control and soybean tolerance with co-application of pyraflufen-ethyl and glyphosate. Pyraflufen-ethyl applied at 11, 23, or 45 g ai/ha in combination with glyphosate did not affect control of barnyardgrass, browntop millet, redroot pigweed, sicklepod, or smellmelon compared to glyphosate alone or co-applied with chlorimuron. Initial benefit (7 DAT) to pitted morningglory control with pyraflufen-ethyl plus glyphosate compared to glyphosate alone or co-applied with chlorimuron was not observed 28 DAT. Hemp sesbania control was increased by pyraflufen-ethyl at 45 g/ha plus glyphosate and glyphosate plus chlorimuron relative to glyphosate applied alone. Pyraflufen-ethyl plus glyphosate resulted in significant visual soybean injury, and a reduction in soybean yield was observed with pyraflufen-ethyl at 45 g/ha relative to glyphosate applied alone or in combination with chlorimuron. Results from a weed-free study confirmed crop injury and yield reduction potential with pyraflufen-ethyl plus glyphosate. Overall results suggest no benefit with respect to weed control or crop tolerance to pyraflufen-ethyl inclusion in a glyphosate-resistant soybean weed control program over that observed with currently registered co-application of glyphosate and chlorimuron.


1994 ◽  
Vol 8 (4) ◽  
pp. 679-683 ◽  
Author(s):  
Teresa S. Willard ◽  
James L. Griffin ◽  
Daniel B. Reynolds ◽  
Arnold M. Saxton

Field-studies were conducted over two years to determine the area of influence and duration of interference of wild poinsettia in soybean. Soybean canopy width averaged across years was reduced approximately 10% beginning at 6 wk of interference for both the 0- to 10-and 10-to 20-cm distances from the weed. Soybean dry weights decreased from 14 to 38% within 20 cm of the weed for 12 through 18 wk of interference. In 1990, soybean yield within 10 cm of wild poinsettia was similar to distances of 10 to 20 and 20 to 40 cm, but was less than that for distances greater than 40 cm from the weed. Weed interference resulted in a 9.5% yield reduction in the 0- to 10-cm distance when compared with the 80-to 100-cm distance. In contrast, yield of soybean in 1991 growing within 10 cm of the weed was less than at greater distances, corresponding to an 18% yield reduction when compared with 80 to 100 cm. Differences in wild poinsettia dry weights when growing alone and when growing within the soybean row occurred after 6 and 8 wk of interference in 1990 and 1991, respectively. In 1991 when rainfall during the growing season was twice that of the previous year, canopy width and dry weight of wild poinsettia growing within the soybean row were reduced an average of 57 and 82%, respectively, compared with weeds growing alone.


Weed Science ◽  
1987 ◽  
Vol 35 (5) ◽  
pp. 663-668 ◽  
Author(s):  
Thomas C. Harris ◽  
Ronald L. Ritter

Effects of a natural mixed stand of giant green foxtail [Setaria viridisvar.major(Gaudin) Pospichel # SETVM] and fall panicum [Panicum dichotomiflorumMichx. # PANDI] on soybean [Glycine max(L.) Merr. ‘Union’ and ‘Essex′] biomass and seed yield were investigated during 1981, 1982, and 1983. Plots maintained weed free for 2 weeks after soybean emergence produced yields equal to those maintained weed free for the season despite any grass reinfestation. Grasses growing naturally with soybeans for 8 weeks after soybean emergence did not reduce crop yields. Weeds not removed after 8 weeks reduced soybean yields by decreasing the number of pods per plant. Under drought conditions, yield reduction due to grass competition did not occur until 12 to 16 weeks after soybean emergence. Hand-established densities of 1 grass plant/7.5 cm of crop row reduced soybean yield by 0 to 11%. Natural grass infestations reduced soybean yield by 21 to 41%.


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