Weed Control from Imazaquin and Metolachlor in No-till Soybeans (Glycine max)

Weed Science ◽  
1989 ◽  
Vol 37 (3) ◽  
pp. 392-399 ◽  
Author(s):  
Douglas D. Buhler ◽  
Virginia L. Werling

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.

Weed Science ◽  
1988 ◽  
Vol 36 (5) ◽  
pp. 629-635 ◽  
Author(s):  
Virginia L. Werling ◽  
Douglas D. Buhler

Clomazone at 0.7 kg ai/ha or more, applied early preplant, completely controlled weeds before planting of no-till soybeans. Under low weed density (57 plants/m2in untreated control) in 1985, grass weed control was nearly complete and not affected by clomazone application time. Late-season broadleaf weed control was less with preemergence application of clomazone at 1.1 or 1.4 kg/ha than with an early preplant or early preplant-preemergence split application of the same clomazone rate. Addition of metribuzin at 0.2 kg ai/ha overcame this control deficiency. Under greater weed densities (330 plants/m2in untreated control) during 1986 and 1987, early preplant-preemergence split applications gave the greatest control of both grass and broadleaf weeds throughout the growing season. Preemergence application of clomazone failed to completely control common lambsquarters emerged at the time of application. Early preplant applications failed to maintain redroot pigweed control throughout the season. Differences in soybean yield were attributed to differences in weed control. No significant carryover of clomazone residue was detected through greenhouse or field bioassays.


1989 ◽  
Vol 3 (4) ◽  
pp. 621-626 ◽  
Author(s):  
David L. Regehr ◽  
Keith A. Janssen

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.


Weed Science ◽  
1998 ◽  
Vol 46 (1) ◽  
pp. 105-110 ◽  
Author(s):  
William G. Johnson ◽  
Jeffrey S. Dilbeck ◽  
Michael S. DeFelice ◽  
J. Andrew Kendig

Field studies were conducted at three locations in 1993 and 1994 to evaluate weed control and crop response to metolachlor plus combinations of 0.5 × and 1 × label rates of imazaquin applied preplant and imazethapyr applied early postemergence or postemergence in no-till narrow-row soybean production. Giant foxtail, common ragweed, common cocklebur, and large crabgrass population reductions were greater with sequential preplant metolachlor plus imazaquin followed by early postemergence or postemergence imazethapyr than with preplant metolachlor plus imazaquin or early postemergence/postemergence imazethapyr alone. Ivyleaf morningglory was not effectively controlled by any herbicide program. Pennsylvania smartweed populations were reduced with all herbicide treatments. Soybean yields with treatments utilizing 0.5 × rates were usually equal to 1 × rates if imazethapyr was applied early postemergence or postemergence. Net income with reduced herbicide rates was equal to full-label rates and provided no greater risk to net income.


Weed Science ◽  
1979 ◽  
Vol 27 (5) ◽  
pp. 520-526 ◽  
Author(s):  
George Kapusta

Twenty herbicide treatments were evaluated on conventional-till (plow, disc, and harrow), minimum-till (disc only), and no-till planted soybeans [Glycine max(L.) Merr.] from 1976 through 1978 at the Belleville Research Center in St. Clair County, Illinois. The soil type was a Weir silt loam (Typic Ochraqualf) characterized by poor internal drainage and 1.2% organic matter. Weed population by species, weed control, and soybean population, injury, and yield were obtained. Fall panicum (Panicum dichotomiflorumMichx.) and giant foxtail (Setaria faberiHerrm.) were the dominant species in all tillage systems, exceeding 1 million plants/ha in the conventional and no-till plots. These species and ivyleaf morningglory [Ipomoea hederacea(L.) Jacq.] were the most difficult to control each year. Weed control was the poorest in the no-till plots because of the large size of the weeds at the time of herbicide application, insufficient rainfall following, and because the plots were not cultivated. The soybean population was equal in all tillage systems except in 1976 when the no-till population exceeded that in the other tillage systems. Treatments that included oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide) caused 42 and 35% soybean injury in the 1976 minimum and no-till plots, respectively. Postemergence-applied naptalam (N-1-naphthylphthalamic acid) plus dinoseb (2-sec-butyl-4,6-dinitrophenol) caused leaf burn each year that ranged from 5 to 35% but all plants recovered within several weeks of application. The seedbed tillage method and herbicide treatments did not significantly affect soybean yields in 1976 when all the herbicides were effective. No-till yields in 1977 and 1978 were substantially lower than yields in conventional and minimum-till plots because of poor weed control. Soybean yields were 2506, 2466, and 1714 kg/ha in the conventional-till, minimum-till, and no-till plots, respectively, when averaged over the 3 yr and 20 herbicide treatments.


1993 ◽  
Vol 7 (2) ◽  
pp. 317-321 ◽  
Author(s):  
C. Dale Monks ◽  
John W. Wilcut ◽  
John S. Richburg

Chlorimuron applied alone and in combination with acifluorfen or thifensulfuron was evaluated for POST control of common lambsquarters, common ragweed, common cocklebur, and a mixture of pitted, ivyleaf, entireleaf, and tall morningglory in soybean. Common cocklebur control was similar with thifensulfuron at 3 and 4 g ae ha−1and with chlorimuron at 7 and 9 g ae ha−1, Common ragweed and morningglory control was greater with chlorimuron while common lambsquarters control was greater with thifensulfuron. Control of all species was good with combinations of chlorimuron at 7 g ha−1plus thifensulfuron at 2 g ha−1or acifluorfen at 140 g ae ha−1and similar to or greater than the control with chlorimuron at 9 g ha−1. Soybean yields with all POST herbicide treatments were equivalent to that of the weed-free check.


Weed Science ◽  
1984 ◽  
Vol 32 (1) ◽  
pp. 17-19 ◽  
Author(s):  
Edward L. Robinson ◽  
George W. Langdale ◽  
John A. Stuedemann

Postemergence applications or a combination of preemergence and postemergence treatments in double cropped soybeans [Glycine max (L.) Merr. ‘Ransom’] resulted in higher soybean yields than preemergence applications. Preemergence-treated plots were 98% weed free early in the growing season; however, weeds emerged later and reduced yields. Weeds had to be controlled in soybeans for 90% of the growing season to avoid yield loss. Soybean yields were higher under no-till than conventionally tilled management in two of three years and tended to be higher during the third year. Distribution and timing of rainfall were more important in determining soybean yield than the total amount received during the growing season.


Weed Science ◽  
1991 ◽  
Vol 39 (2) ◽  
pp. 232-237 ◽  
Author(s):  
J. Boyd Carey ◽  
Michael S. Defelice

Field studies were conducted to evaluate the influence of herbicide application timing on weed control in no-till soybean production. Row spacing generally had no effect on weed control. Herbicide treatments containing chlorimuron plus metribuzin applied as many as 45 days prior to planting in 1988 and 1989 controlled broadleaf weeds throughout the growing season. Imazaquin applied 45 and 30 days prior to planting provided poor control of common cocklebur in 1989. Giant foxtail control was inconsistent with all herbicide treatments. Soybean yields subsequent to early preplant herbicide applications were greater than or equal to those in which applications were made at planting when late-season weed control was adequate. Herbicides applied preemergence did not control high densities of common lambsquarters in 1989.


1998 ◽  
Vol 12 (1) ◽  
pp. 137-144 ◽  
Author(s):  
Kelly A. Nelson ◽  
Karen A. Renner

Field experiments were conducted at East Lansing and Clarksville, MI, to evaluate the efficacy of imazamox, imazethapyr, and CGA-277476 plus quizalofop applied postemergence in wide- (76-cm) and narrow- (19-cm) row soybean. Soybean injury from all herbicides was minimal 14 days after treatment (DAT), except for CGA-277476 at 79 g ai/ha plus 69 g ai/ha quizalofop, which caused 30% soybean injury at the Clarksville location. Adding 4 g ai/ha CGA-248757 to 65 g ai/ha CGA-277476 plus quizalofop reduced common ragweed control, but increased redroot pigweed control in wide rows compared to 79 g ai/ha CGA-277476 plus quizalofop. Imazamox at 35 and 45 g ai/ha provided greater common ragweed and common lambsquarters control than imazethapyr at 70 g ai/ha 28 DAT. All herbicide treatments controlled velvetleaf. Common ragweed and common lambsquarters control by all herbicide treatments was enhanced in narrow- compared to wide-row soybean 56 DAT as was redroot pigweed control by CGA-277476 treatments. Total weed biomass and soybean yield in wide-row soybean treated with imazamox at 45 g/ha was not different from the hand-weeded control. In narrow-row soybean, soybean yield was equal to the hand-weeded control for 35 and 45 g/ha imazamox and 70 g/ha imazethapyr. Postemergence herbicide treatments resulted in less weed biomass and greater soybean yield in narrow- compared to wide-row soybean.


Weed Science ◽  
1971 ◽  
Vol 19 (4) ◽  
pp. 372-377 ◽  
Author(s):  
B. J. Johnson

Vernolate (S-propyl dipropylthiocarbamate) injected into a sandy loam soil controlled a higher percentage of early weeds in soybeans (Glycine max(L.) Merr.) in 2 years out of 3 when compared with incorporated vernolate at the same rate by conventional methods. Late season weed control was enhanced by split applications of herbicides applied postemergence in sequence with vernolate. Chloroxuron (3-[p-(p-chlorophenoxy)phenyl]-1,1-dimethylurea) applied early postemergence plus 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (linuron) or 2,4-bis-(isopropylamino)-6-(methylthio)-s-triazine (prometryne) applied in split applications as late and layby treatments gave the best weed control. Prometryne caused chlorotic veination in the upper leaves of the plants each year. In 1970, when prometryne was applied in sequence with incorporated vernolate, soybean plants were injured 30% compared with only 8% injury when the same herbicide was applied in sequence with injected vernolate at the same rate. The average seed yields were higher from injected vernolate at 1.12 kg/ha than from incorporated vernolate at 2.24 kg/ha. There was no difference in yield when vernolate was incorporated or injected at the same rate. Seed yields from the 3-year average were lower from plots treated with prometryne than from plots treated with linuron or 2-sec-butyl-4,6-dinitrophenol (dinoseb). Generally, the soybean seed quality was lower and seed size smaller when herbicide treatments failed to control weeds throughout the growing season.


Weed Science ◽  
1985 ◽  
Vol 33 (5) ◽  
pp. 679-685 ◽  
Author(s):  
Russell S. Moomaw ◽  
Alex R. Martin

Weed control in no-till soybeans [Glycine max(L.) Merr. ‘Wells’] planted into shredded corn (Zea maysL.) residue was evaluated at Concord, NE, over a 3-yr period. Herbicide factors evaluated were time of herbicide application for no-till soybeans, efficacy of glyphosate [N-(phosphonomethyl)glycine] relative to paraquat (1,1’-dimethyl-4,4’-bipyridinium ion) for control of emerged weeds, and the efficacy of alachlor [2-chloro-2’,6’-diethyl-N-(methoxymethyl)acetanilide], metolachlor [2-chloro-N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide], oryzalin (3,5-dinitro-N4,N4-dipropylsulfanilamide), and pendimethalin [N-(1-ethylpropyl)-3,4-dimethyl-2,6-dinitrobenzenamine] for residual weed control. Combination residual and contact herbicide treatments were applied either as a preplant surface application or preemergence after no-till-planted soybeans. Removal of existing weed growth was not consistently better with the preplant surface application compared to later removal after soybean planting. Paraquat and glyphosate gave nearly equal control of emerged weeds. Addition of 2,4-D [(2,4-dichlorophenoxy)acetic acid] with paraquat in the tank mix did not improve weed control. Use of narrow, ripple coulters on the no-till planter resulted in minimal disturbance of the preplant surface herbicide so that additional preemergence herbicide at planting was seldom beneficial.


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