scholarly journals Effect of reduced herbicide rates on weed control, environmental impact and profitability of corn

2009 ◽  
Vol 89 (5) ◽  
pp. 969-975
Author(s):  
Nader Soltani ◽  
Richard J Vyn ◽  
Laura L Van Eerd ◽  
Christy Shropshire ◽  
Peter H Sikkema

A study was conducted over a 3-yr period (2003, 2004, and 2005) to evaluate the effect of reduced herbicide rates - 20, 40, 60, 80, and 100% of the manufacturer’s recommended rate (MRR) - on weed biomass reduction, environmental impact (EI), yield, and profitability of corn (Zea mays L.) in Ontario. The herbicide rate required to provide 95% biomass reduction of velvetleaf (Abutilon theophrasti Medic.), redroot pigweed (Amaranthus retroflexus L.), common ragweed (Ambrosia artemisiifolia L.), common lambsquarters (Chenopodium album L.), and annual grasses was 92, 30, 41, 28, and 83% of the MRR for isoxaflutole plus atrazine, >200, 119, 23, 23, and 117% of the MRR for dimethenamid plus dicamba/atrazine, 141, 72, 46, 45, and >200% of the MRR for glufosinate plus atrazine, and 81, 29, 18, 24, and 88% of the MRR for nicosulfuron/rimsulfuron plus dicamba/diflufenzopyr, respectively. The herbicide rate required to provide 95% of weed-free corn yield was 61, 22, 130, and 11% of the MRR for isoxaflutole plus atrazine, dimethenamid plus dicamba/atrazine, glufosinate plus atrazine, and nicosulfuron/rimsulfuron plus dicamba/diflufenzopyr, respectively. Nicosulfuron/rimsulfuron plus dicamba/diflufenzopyr had the lowest EI. The results of profitability analysis suggested that the MRR rates do not tend to maximize profit margins. In most cases, there were no significant differences in profit margins for treatments with 40, 60, 80, and 100% of the MRR. Key words: Atrazine, dicamba, diflufenzopyr, dimethenamid, glufosinate, nicosulfuron, rimsulfuron, Zea mays L.

2010 ◽  
Vol 90 (1) ◽  
pp. 125-132 ◽  
Author(s):  
N. Soltani ◽  
L L Van Eerd ◽  
R J Vyn ◽  
C. Shropshire ◽  
P H Sikkema

Eight field trials were conducted over a 3-yr period at Exeter (one site in 2005 and 2006) and Ridgetown (three sites in 2005, two sites in 2006 and one site in 2007), Ontario, to evaluate different postemergence glyphosate tank mixes for weed management in glyphosate-tolerant corn. Treatments included a weedy check, a single application of glyphosate, a sequential application of glyphosate and tank mixes of glyphosate plus either atrazine, dicamba/atrazine, mesotrione, s-metolachlor plus atrazine, s-metolachlor/atrazine, dicamba/diflufenzopyr, and dimethenamid plus atrazine. A single application of glyphosate, the sequential application of glyphosate and tank mixes of glyphosate plus either atrazine, dicamba/atrazine, mesotrione, s-metolachlor plus atrazine, s-metolachlor/atrazine, dicamba/diflufenzopyr, and dimethenamid plus atrazine provided 92-100% control of redroot pigweed, 87-100% control of common ragweed, 74-100% control of common lambsquarters, and 43-100% control of green foxtail. All herbicide treatments had a higher yield than the weedy check. There were no differences in corn yield among the herbicide treatments evaluated. The glyphosate alone or in tank mix combination with mesotrione or dicamba/diflufenzopyr programs had the lowest environmental impact. Glyphosate plus atrazine and dicamba/diflufenzopyr were the most profitable weed management programs in glyphosate-tolerant corn.Key words: Atrazine, dicamba, diflufenzopyr, dimethenamid, glyphosate, mesotrione, pendimethalin, rimsulfuron, s-metolachlor, Zea mays L.


Weed Science ◽  
1999 ◽  
Vol 47 (4) ◽  
pp. 375-382 ◽  
Author(s):  
Christy L. Sprague ◽  
Donald Penner ◽  
James J. Kells

Field studies were conducted in 1996 and 1997 to determine the effects of RP-201772 and RP-201772 tank mixtures applied to emergedZea mays.RP-201772 at 105 g ha−1and tank-mixed metolachlor/benoxacor or atrazine were applied preemergence and to spike, 2-leaf, and 4-leafZ. mays.Herbicide treatments over the four application timings provided greater than 90%Chenopodium album, Ambrosia artemisiifolia, Amaranthus retroflexus, andAbutilon theophrasticontrol. However,Setaria fabericontrol varied among years and application timings. SevereZ. maysinjury, 70% and 40%, was observed when RP-201772 tank-mixed with metolachlor/benoxacor was applied to 2-leaf and 4-leafZ. mays, respectively. Greenhouse studies confirmedZ. mayssensitivity from delayed applications of RP-201772 tank-mixed with metolachlor/benoxacor. Similarly, increasedZ. maysinjury was observed from postemergence applications of RP-201772 tank-mixed with acetochlor/MON-13900. Herbicide absorption, translocation, metabolism, and retention studies were conducted to determine the physiological basis for the observedZ. maysinjury from delayed applications of the RP-201772 tank mixture with metolachlor/benoxacor. Metolachlor/benoxacor increased radiolabeled RP-201772 absorption when applied to spike, 2-leaf, and 4-leafZ. mays.RP-201772 translocation and metabolism did not explain enhancedZ. maysinjury. However, RP-201772 retention increased fivefold when metolachlor/benoxacor was present in the spray solution and applied to 2-leaf and 4-leafZ. mays.Increased RP-201772 absorption and retention appeared to be the basis forZ. maysinjury when tank-mixed with metolachlor/benoxacor and applied to emergedZ. mays.


2007 ◽  
Vol 87 (3) ◽  
pp. 671-678 ◽  
Author(s):  
N. Soltani ◽  
L. L. Van Eerd ◽  
R. J. Vyn ◽  
C. Shropshire ◽  
P. H. Sikkema

Field experiments were conducted from 2003 to 2005 in Ontario to determine if reduced rates of imazethapyr (< 75 g a.i. ha-1) tank-mixed with dimethenamid applied preemergence (PRE) can be used as a feasible weed management strategy for broad-spectrum weed control in white and kidney beans (Phaseolus vulgaris L.). There was no injury in white or kidney bean with the imazethapyr plus dimethenamid tank-mix treatments evaluated. The rate of imazethapyr required to provide adequate control of green foxtail [Setaria viridis (L.) P. Beauv.], lamb’s-quarters (Chenopodium album L.), common ragweed (Ambrosia artemisiifolia L.), wild mustard (Sinapis arvensis L.), and redroot pigweed (Amaranthus retroflexus L.) tended to be reduced when tankmixed with dimethenamid at 1000 g ha-1. There was no adverse effect on the yield of white and kidney beans at the highest rate (75 g a.i. ha-1) of imazethapyr evaluated. Although both herbicides are considered reduced risk, the environmental impact of imazethapyr (75 g a.i. ha-1) was seven times less than that of dimethenamid (1000 g a.i. ha-1). The addition of reduced rates of imazethapyr to dimethenamid did not significantly increase environmental impact (EI) vs. dimethenamid alone. Profit margins were greater when dimethenamid was tank-mixed with imazethapyr than for applications of imazethapyr alone. Across all treatments, profit margins were maximized at an imazethapyr rate of 60 g a.i. ha-1 for white bean and an imazethapyr rate of between 60 and 75 g a.i. ha-1 for kidney bean. However, the profit-maximizing rates of imazethapyr tended to be higher for treatments without dimethenamid than for treatments where dimethenamid was tank-mixed with imazethapyr. Key words: Dimethenamid, environmental impact quotient (EIQ), imazethapyr, Montcalm, OAC Thunder, Phaseolus vulgaris L., profit margin


Weed Science ◽  
1979 ◽  
Vol 27 (6) ◽  
pp. 608-611 ◽  
Author(s):  
A. G. Ogg ◽  
S. Drake

Alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide] at 3.4 kg/ha, EPTC (S-ethyl dipropylthiocarbamate) + R-25788 (N,N-diallyl-2,2-dichloroacetamide) at 4.5 + 0.4 and 9.0 + 0.8 kg/ha, vernolate (S-propyl dipropylthiocarbamate) + R-25788 at 4.5 + 0.4 and 9.0 + 0.8 kg/ha, metolachlor [2-chloro N-(2-ethyl-6-methylphenyl)-N-(2-methoxy-1-methylethyl)acetamide] at 1.7 and 3.4 kg/ha, and metolachlor + procyazine {2-[[4-chloro-6-(cyclopropylamino)1,3,5-triazine-2-yl] amino]-2-methylpropanenitrile} at 1.3 + 1.3 kg/ha were preplant incorporated. These herbicides controlled 95% or more of the barnyardgrass [Echinochloa crus-galli (L.) Beauv.], common lambsquarters (Chenopodium album L.), redroot pigweed (Amaranthus retroflexus L.), Powell amaranth (A. powellii S. Wats.), and yellow foxtail [Setaria lutescens (Weigel) Hubb.] without injuring sweetcorn (Zea mays L. ‘Golden Jubilee’) or reducing corn yields or quality. Similar results were obtained with preplant incorporated applications of butylate (S-ethyldiisobutylthiocarbamate) + R-25788 at 4.5 + 0.2 kg/ha followed by a postemergence application of the amine salt of 2,4-D [(2,4-dichlorophenoxy)acetic acid] at 0.6 kg/ha. Metribuzin [4-amino-6-tert-butyl-3-(methylthio)-as-triazin-5(4H)-one] at 0.3 and 0.6 kg/ha and metribuzin + alachlor at 0.6 + 2.2 kg/ha applied preplant and incorporated reduced corn stands, primary ear production, and corn yields significantly. None of the herbicides significantly affected total sugars, reducing sugars, soluble solids, moisture content, or succulence of the corn.


Weed Science ◽  
1994 ◽  
Vol 42 (4) ◽  
pp. 568-573 ◽  
Author(s):  
Stevan Z. Knezevic ◽  
Stephan F. Weise ◽  
Clarence J. Swanton

Redroot pigweed is a major weed in corn throughout Ontario. Field experiments were conducted at two locations in 1991 and 1992 to determine the influence of selected densities and emergence times of redroot pigweed on corn growth and grain yield. Redroot pigweed densities of 0.5, 1, 2, 4 and 8 plants per m of row were established within 12.5 cm on either side of the corn row. In both years, redroot pigweed seeds were planted concurrently and with corn at the 3- to 5-leaf stage of corn growth. A density of 0.5 redroot pigweed per m of row from the first (earlier) emergence date of pigweed (in most cases, up to the 4-leaf stage of corn) or four redroot pigweed per m of row from the second (later) emergence date of pigweed (in most cases, between the 4- and 7-leaf stage of corn) reduced corn yield by 5%. Redroot pigweed emerging after the 7-leaf stage of corn growth did not reduce yield. Redroot pigweed seed production was dependent upon its density and time of emergence. The time of redroot pigweed emergence, relative to corn, may be more important than its density in assessing the need for postemergence control.


1994 ◽  
Vol 74 (2) ◽  
pp. 375-381 ◽  
Author(s):  
M. E. Reidy ◽  
C. J. Swanton

Laboratory and field experiments were established to determine the optimum dose and timing of postemergence applications of DPX-79406 for quackgrass control. Four node quackgrass rhizome fragments from each biotype were grown under controlled conditions. At the three-to-four-leaf stage, quackgrass plants were sprayed with DPX-79406 and evaluated for control. A significant response of quackgrass biotypes to DPX-79406 was evident only at lower doses. In the field, quackgrass was effectively controlled by all doses of DPX-79406. Significant growth-stage effects were observed for quackgrass shoot and rhizome dry weights in the year of application and in the year following application. There was a significant interaction between year and growth stage. In 1990, quackgrass biomass was greater when DPX-79406 was applied at the two-to-three-leaf stage of quackgrass than at the four-to-five-leaf stage. In 1991, however, the opposite occurred. Within a growth stage, the 6.25 g ha−1 dose was as effective for controlling quackgrass as 18.5 g ha−1, in both years of the study. In 1991, significant decreases in corn yield were observed for DPX-79406 doses of > 12.5 g ha−1 applied at the four-to-five-leaf stage of quackgrass. For all the variables studied, DPX-79406 doses of 6.25–12.5 g ha−1 resulted in consistent control of quackgrass. Key words: DPX-79406, nicosulfuron, rimsulfuron, quackgrass, Elytrigia repens, corn, Zea mays


2013 ◽  
Vol 31 (3) ◽  
pp. 247-254 ◽  
Author(s):  
Yusuf Kaya ◽  
Ozkan Aksakal ◽  
Serap Sunar ◽  
Filiz Aygun Erturk ◽  
Sedat Bozari ◽  
...  

1978 ◽  
Vol 58 (2) ◽  
pp. 221-228 ◽  
Author(s):  
J. R. OKALEBO ◽  
A. F. MacKENZIE

Effects of mono-, diammonium, and superphosphate with added urea or ammonium nitrate on corn (Zea mays L.) growth were studied in the field in 1971 and 1972. At the rate of 100 kg P2O5/ha, none of the carriers affected emergence of seedlings in five Quebec soils. Leaf P content at silking time was of little benefit in predicting P status of the plants, or in differentiating among the carriers. Phosphorous applications gave significant corn yield increases, with carriers performing alike when averaged over all sites. However, some yield differences among carriers occurred on some soil types and seasons. These carrier differences were not consistent and remain to be clarified. The ammonium phosphates compared with the check generally hastened maturity but reduced potassium levels in leaf tissue of corn.


2018 ◽  
Vol 9 (1) ◽  
pp. 25-32
Author(s):  
Sergio Iglesias ◽  
Julio Alegre ◽  
Carlos Salas ◽  
José Egüez
Keyword(s):  
Zea Mays ◽  

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