Effects of Johnsongrass (Sorghum halepense), Hemp Sesbania (Sesbania exaltata), and Delayed Harvest on Soybeans

1993 ◽  
Vol 7 (2) ◽  
pp. 355-360 ◽  
Author(s):  
Chester G. McWhorter ◽  
James M. Anderson

The effect of delayed harvest was investigated with two soybean cultivars that were grown weed free or in competition with johnsongrass or hemp sesbania over a 3-yr period. Johnsongrass reduced the yield of early-maturing ‘Hill’ soybean 32, 35, and 36% when harvested at an average of 1, 2, or 3 wk after maturity, when compared to weed-free yields of 2490, 2430, and 2270 kg ha−1, respectively. Late-maturing ‘Lee 68’ yields were reduced 27, 29, and 39% on three harvest dates compared to weed-free yields of 2570, 2310, and 2200 kg ha−1, respectively. Seed grades of both cultivars improved with delayed harvest, but this was offset when johnsongrass was present. Hemp sesbania reduced yields of Hill 23% on the first harvest date and 26% on the second and third dates. Yields of Lee 68 were reduced 16, 22, and 28% by hemp sesbania on three successive harvest dates. The value of soybean yields adjusted for excessive foreign material, moisture, and damaged kernels was decreased by delayed harvest when hemp sesbania was present in Lee 68 and when johnsongrass was present in both cultivars.

Weed Science ◽  
1979 ◽  
Vol 27 (1) ◽  
pp. 58-64 ◽  
Author(s):  
C. G. McWhorter ◽  
J. M. Anderson

The competitive effects of hemp sesbania [Sesbania exaltata(Raf.) Cory] on soybeans [Glycine max(L.) Merr. ‘Forrest’] were studied on Sharkey clay for 2 yr. In full-season competition, hemp sesbania populations of 1,600, 3,200, 3,900, and 5,500 plants/ha did not reduce adjusted soybean yields, but populations of 8,100 to 129,200 plants/ha reduced yields 10 to 80%. Competition by hemp sesbania at 68,000 plants/ha for 1 to 4 weeks after soybean emergence reduced soybean yields 8% or less, whereas competition by the same population for 6, 8, and 10 weeks after soybean emergence reduced adjusted yields 18, 27, and 43%, respectively. Hemp sesbania populations of 3,200 plants/ha or more reduced the grade of harvested soybeans and populations of 5,500 plants/ha increased the level of foreign material found in seed samples taken at harvest. Hemp sesbania populations above 10,700 plants/ha increased the levels of damaged kernels and moisture in harvested soybean seed. Early-season control was required for highest soybean yields and total returns. The most critical period for control was 4 to 10 weeks after emergence of soybeans.


Weed Science ◽  
1979 ◽  
Vol 27 (1) ◽  
pp. 42-47 ◽  
Author(s):  
C. G. McWhorter ◽  
W. L. Barrentine

Mefluidide {N-[2,4-dimethyl-5-[[(trifluoromethyl)sulfonyl]-amino] phenyl] acetamide} was applied postemergence in soybean [Glycine max (L.) Merr.] fields and its effectiveness in controlling johnsongrass [Sorghum halepense (L.) Pers.], hemp sesbania [Sesbania exaltata (Raf.) Cory], and common cocklebur (Xanthium pensylvanicum Wallr.) was evaluated. In plots treated preplanting with trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), mefluidide gave 95% johnsongrass control when it was applied postemergence (over-the-top without surfactant) once at 0.90 kg/ha or twice at 0.44 kg/ha. Directed sprays of mefluidide at 0.22 to 0.67 kg/ha without surfactant were more effective on johnsongrass than similar treatments applied over-the-top. When 0.5% (v/v) nonoxynol [α-(p-nonyl-phenyl)-ω-hydroxypoly (oxyethylene)] surfactant was added, mefluidide at 0.44 or 0.67 kg/ha applied as directed or over-the-top sprays provided 76 to 90% johnsongrass control. Mefluidide at 1.12 kg/ha plus nonoxynol surfactant, applied as a directed spray, was required to provide 81% control of hemp sesbania. Directed sprays containing mixtures of mefluidide at 0.28 kg/ha plus dinoseb (2-sec-butyl-4,6-dinitrophenol) at 2.2 kg/ha, or mefluidide at 0.28 kg/ha plus a 2:1 mixture of naptalam (N-1-naphthylphthalamic acid)/dinoseb at 4.7 L/ha, effectively controlled 40- to 60-cm-tall hemp sesbania. A single, directed spray of mefluidide at 0.56 kg/ha plus nonoxynol provided 92% common cocklebur control, and mixtures of mefluidide at 0.28 kg/ha plus dinoseb at 2.2 kg/ha or naptalam/dinoseb (a 2:1 mixture) at 4.7 L/ha increased control above that provided by either of the herbicides alone.


Weed Science ◽  
1977 ◽  
Vol 25 (2) ◽  
pp. 135-141 ◽  
Author(s):  
C.G. McWhorter

Field experiments were conducted to study the feasibility of applying glyphosate [N-(phosphonomethyl)glycine] postemergence for the control of johnsongrass [Sorghum halepense(L.) Pers.], redroot pigweed (Amaranthus retroflexusL.), and hemp sesbania [Sesbania exaltata(Raf.) Cory] in soybeans [Glycine max(L.) Merr.]. Herbicide sprays were directed across the row to weeds growing taller than soybeans in June, July, and August. Herbicide not sprayed on weeds was trapped and reused. Glyphosate at 1.12 and 1.68 kg/ha effectively controlled johnsongrass with little soybean injury and with greatly increased soybean yields. The use of 0.1% surfactant frequently increased the toxicity of glyphosate at 1.12 and 1.68 kg/ha to soybeans, but this adverse effect was overcome by the use of 0.1% anti-drift polymer in sprays. Control of redroot pigweed with glyphosate at 1.12 kg/ha was improved by the use of 0.1% surfactant, but surfactant did not increase control with glyphosate at 1.68 kg/ha. Glyphosate at 1.68 kg/ha, with 0.1% surfactant, was required to provide more than 80% control of hemp sesbania. Glyphosate applied at 1.12 kg/ha in the recirculating sprayer provided equal johnsongrass control, increased soybean yields and caused less soybean injury than when glyphosate at 0.56 kg/ha was applied over-the-top in water or in foam.


1986 ◽  
Vol 66 (1) ◽  
pp. 125-130 ◽  
Author(s):  
G. H. FRIESEN ◽  
D. A. WALL

McCall, Maple Presto, Maple Amber and OT80-3 soybean (Glycine max (L.) Merr.) cultivars were evaluated under field conditions for their response to metribuzin. Maple Amber was found to be less tolerant than the other cultivars. In controlled environment chamber studies, injury to this cultivar was more severe on a sandy loam soil than on a clay loam soil. Fall applications of metribuzin, alone or tank-mixed with trifluralin, were tolerant to Maple Amber soybeans and such applications may offer a practical alternative to spring treatments for broad spectrum weed control in the less tolerant soybean cultivars grown in Manitoba.Key words: Metribuzin, trifluralin, preplant incorporation, fall treatments, soybean cultivars


2000 ◽  
Vol 92 (3) ◽  
pp. 532-537 ◽  
Author(s):  
Dennis B. Egli ◽  
William P. Bruening

Weed Science ◽  
1979 ◽  
Vol 27 (5) ◽  
pp. 479-485 ◽  
Author(s):  
J. E. Dale ◽  
J. M. Chandler

The feasibility of herbicide and crop rotation for the control of johnsongrass [Sorghum halepense(L.) Pers.] in corn (Zea maysL.) was studied in field experiments. Light infestations of johnsongrass were initially present, but it became the predominant weed after 4 yr of continuous corn treated with atrazine [2-chloro-4-(ethylamino)-6-(isopropylamine)-s-triazine], cyanazine {2-[[4-chloro-6-(ethylamino)-s-triazin-2-yl]amino]-2-methylpropionitrile}, and linuron [3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea], alone and in combinations at rates of 2.24, 2.24, and 0.84 kg/ha, respectively. The infestation of johnsongrass was effectively controlled by growing corn in rotation with cotton (Gossypium hirsutumL.) in a cropping sequence of corn-cotton-cotton-corn, in which trifluralin (α,α,α-trifluoro-2,6-dinitro-N,N-dipropyl-p-toluidine), fluometuron [1,1-dimethyl-3-(α,α,α-trifluoro-m-tolyl)urea] and MSMA (monosodium methanearsonate) at 0.56, 2.24, and 2.24 kg/ha respectively, were used for weed control in cotton. In the corn-cotton-cotton-corn cropping sequence, the herbicide treatments also prevented increases in the populations of other indigeneous weeds including prickly sida (Sida spinosaL.), prostrate spurge (Euphorbia supinaRaf.), spotted spurge (Euphorbia maculataL.), common purslane (Portulaca oleraceaL.), tall morningglory [Ipomoea purpurea(L.) Roth], common cocklebur (Xanthium pensylvanicumWallr.), spurred anoda[Anoda cristata(L.) Schlecht.], hemp sesbania [Sesbania exaltata(Raf.) Cory], redroot pigweed (Amaranthus retroflexusL.), goosegrass [Eleusine indica(L.) Gaertn.], junglerice [Echinochloa colonum(L.) Link], large crabgrass [Digitaria sanguinalis(L.) Scop.], and purple nutsedge (Cyperus rotundusL.).


Weed Science ◽  
1997 ◽  
Vol 45 (1) ◽  
pp. 91-97 ◽  
Author(s):  
C. Andy King ◽  
Larry C. Purcell

Soybean yield loss from weed interference depends upon weed density and competitiveness of crop and weed species in response to environment. Soil water availability and nitrogen fertility were evaluated for their effect on competitiveness of individual species in field experiments. Early-season temperatures in 1995, which were cool compared to 1994, slowed hemp sesbania growth without affecting soybean growth. This resulted in negligible competition with soybean by hemp sesbania at densities of 3 or 6 plants m−2. In 1994, hemp sesbania grew above the soybean canopy, decreasing soybean light interception 29 to 68%, and reducing soybean yield 30 to 48%. Fertilizer nitrogen increased soybean competitiveness, as indicated by biomass production, only in irrigated plots with hemp sesbania at 3 m−2, but did not affect soybean yield. Apparently, competition for light is a primary cause of soybean yield loss from hemp sesbania infestations. In growth chamber studies, simulating temperatures from the field, hemp sesbania growth was stimulated more by warm temperatures than was soybean. Hemp sesbania and soybean dry weights increased 4.4- and 2.7-fold, respectively, at 30/20 C day/night temperatures compared to 25/15 C.


2013 ◽  
Vol 93 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Allen G. Xue ◽  
John Rowsell ◽  
Keh Ming Ho ◽  
Yuanhong Chen ◽  
Dawn T. Chi ◽  
...  

The effect of harvest date on the incidence of seed-borne Fusarium spp. and deoxynivalenol (DON) concentration in barley (Hordeum vulgare L.) was studied using three cultivars at three locations in Ontario in both 2004 and 2005. The profile of seed-borne Fusarium spp. was dominated by F. equiseti (Corda) Sacc., F. sporotrichioides Sherb., and F. poae (Peck) Wollenw., isolated from 4.4%, 3.3%, and 1.6% of the kernels, representing 39.3%, 29.4%, and 14.2% of the Fusarium pathogen population, respectively. Fusarium graminearum Schwabe and F. avenaceum (Fr.) Sacc. were each recovered from <1% of the kernels and represented 8.3% and 6.6% of the pathogen population, respectively. Other species, including F. acuminatum Ellis & Everh., F. culmorum (W.G. Sm.) Sacc., and F. semitectum Berk. & Rav., collectively occurred only on 0.2% of all kernels and represented <2% of the population. The incidence level of all Fusarium spp. increased from 6.9 to 13.9% when harvest was delayed. Of the commonly recovered species, only F. avenaceum and F. sporotrichioides levels increased with the delayed harvest, while other species did not follow a clear pattern. DON concentration in the harvested grain ranged from 0.20 to 0.28 mg kg‑1 with the five harvest dates, and was not statistically different. Significant differences in the incidence of all Fusarium spp. and in DON concentration were observed among cultivars, locations, and between the 2 yr of the study. The highest DON concentration observed in this study was 0.5 mg kg‑1, which is below the Canadian tolerance level of 1.0 mg kg‑1.


Weed Science ◽  
1968 ◽  
Vol 16 (2) ◽  
pp. 252-255 ◽  
Author(s):  
Roy J. Smith

Barnyardgrass [Echinochloa crusgalli (L.) Beauv.], duck-salad [Heteranthera limosa (Sw.) Willd.], hemp sesbania [Sesbania exaltata (Raf.) Cory], and northern jointvetch [Aeschynomene virginica (L.) B.S.P.] significantly reduced rice [Oryza sativa L.] yields. Damage to rice increased as populations of barnyardgrass, hemp sesbania, and northern jointvetch increased. Barnyardgrass and duck-salad lowered yields during early season, but hemp sesbania and northern jointvetch decreased yields in late season.


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