Practical Changes to Single-Boom Sprayers for Zone Herbicide Application

2006 ◽  
Vol 20 (2) ◽  
pp. 502-510
Author(s):  
William W. Donald ◽  
Kelly Nelson
Keyword(s):  
Yield Loss ◽  
Herbicide Application ◽  
Common Waterhemp ◽  
Field Corn ◽  
Giant Foxtail ◽  
Weed Cover ◽  
Generic Alternative ◽  
Reduced Rate

Reduced-rate zone herbicide application (ZHA) consists of banding reduced herbicide rates between crop rows (≤ full broadcast registered rate, 1×) and banding much reduced herbicide rates over crop rows (≪ 1×). The objective of this research was to compare the mechanically complicated dual-boom ZHA sprayer with a much simpler, single-boom ZHA sprayer for controlling giant foxtail and common waterhemp in field corn in 2003 and 2004 in Missouri. The dual-boom ZHA sprayer employed two different herbicide solutions, which were propelled through two booms on separate sprayer systems to apply different herbicide rates over in-row and between-row areas while maintaining similar carrier volumes and coverage through two booms. In contrast, the single-boom ZHA sprayer is a mechanically simpler system in which both herbicide rates and carrier volumes were varied across one boom over in-row (IR) and between-row (BR) areas. In single-boom ZHA, two different nozzle tips were alternated on one boom over in-row and between-row areas, the number of nozzles per boom was doubled, and the distance between nozzles was halved compared with a conventional sprayer boom. In a 2-yr study, these different ZHA sprayers were used to apply preemergence atrazine + S-metolachlor between and over crop rows at various reduced rates (1× = 2,240 + 1,750 g ai/ha, respectively). Among all single- and dual-boom ZHA sprayer treatments and the weed-free checks, corn yields and in-row total weed cover were statistically indistinguishable for both years and for between-row total weed cover in 1 of 2 yr. In both years, a single-boom ZHA system prevented yield loss from competing weeds as effectively as the dual-boom ZHA system. The new single-boom ZHA system is a mechanically simple, inexpensive, generic alternative for reducing herbicide rates and lowering input costs.

Preemergence Banded Herbicides Followed by Only One Between-Row Mowing Controls Weeds in Corn

2006 ◽  
Vol 20 (1) ◽  
pp. 143-149 ◽  
Author(s):  
William W. Donald
Keyword(s):  
Weed Control ◽  
Yield Loss ◽  
Soil Surface ◽  
Corn Yield ◽  
Common Waterhemp ◽  
Giant Foxtail ◽  
Weed Cover ◽  
Minimum Number ◽  
Annual Weeds

Research was conducted to determine the minimum number of between-row mowings necessary to control annual weeds, chiefly giant foxtail and common waterhemp, without corn yield loss. Over 2 yr in Missouri, the between-row mowing systems that were evaluated consisted of a 38-cm band of PRE atrazine plus metolachlor at 2.2 plus 2.2 kg ai/ha applied over corn grown in 76-cm rows shortly after planting followed by one, two, or three between-row mowings close to the soil surface. Based on rated total weed control, between-row total weed cover, and corn yield, the weed-free check was statistically indistinguishable from a treatment in which banded PRE herbicide was followed by only one between-row mowing, late, when weeds were relatively large. When mowed once at 52 to 64 days after planting (DAP), giant foxtail and common waterhemp were greater than 85 cm tall. The yield was not increased by mowing earlier or more than once.

Estimated corn yields using either weed cover or rated control after pre-emergence herbicides

Weed Science ◽  
2006 ◽  
Vol 54 (02) ◽  
pp. 373-379 ◽  
Author(s):  
William W. Donald
Keyword(s):  
Crop Yields ◽  
Nonlinear Function ◽  
Published Data ◽  
Corn Yield ◽  
Visual Evaluation ◽  
Common Waterhemp ◽  
Weed Growth ◽  
Herbicide Treatment ◽  
Giant Foxtail ◽  
Weed Cover

Because soil-residual PRE herbicides reduce and delay annual weed emergence and decrease later weed growth, susceptible weeds surviving or recovering from herbicide treatment reduce crop yields less than do untreated weeds. Recently, corn yields were shown to be reduced differently by untreated weeds emerging in and between crop rows. However, equations have not been reported before that relate corn yield to in-row and between-row weed cover of mixed weed populations recovering from PRE soil-residual herbicides. Published data from PRE herbicide screening research for 3 site-yr in Missouri were reanalyzed to characterize this relation. In-row and between-row weed cover of mixed weed populations, chiefly giant foxtail and common waterhemp, were measured from photographs at midsummer. In 2 of 3 site-yr and with the 3 site-yr average, corn yields were a nonlinear function of both in-row and between-row weed cover recovering from various PRE soil-residual herbicide treatments. In 1 of 3 site-yr, corn yields were a nonlinear function of only between-row total weed cover. Subdividing weed cover into in-row and between-row subpopulations in equations accounted for more data variability in yield estimates than including either subpopulation alone. For all 3 site-yr after PRE herbicide treatment, corn yields were a nonlinear function of only between-row visually rated total weed control. Visual evaluation was less sensitive than photographic weed cover for measuring the contribution of in-row weeds to corn yield loss and characterizing the functional form of the equations.

Weed Management with Reduced Rates of Glyphosate in No-Till, Narrow-Row, Glyphosate-Resistant Soybean (Glycine max)

1999 ◽  
Vol 13 (3) ◽  
pp. 478-483 ◽  
Author(s):  
Jimmy D. Wait ◽  
William G. Johnson ◽  
Raymond E. Massey
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Field Studies ◽  
Net Income ◽  
Single Application ◽  
Economic Returns ◽  
Common Waterhemp ◽  
No Till ◽  
Giant Foxtail ◽  
Reduced Rate

Field studies were conducted at two locations in 1997 and 1998 to evaluate crop injury, weed control, yield, and net economic returns of single and sequential postemergence applications of labeled and reduced rates of glyphosate to no-till, glyphosate-resistant soybean planted in narrow rows. Sequential applications provided at least 91% control of giant foxtail, while single applications provided at least 86% control with labeled rates and 68–93% control with reduced rates. Common waterhemp control was slightly higher with sequential vs. single treatments and with labeled rates vs. reduced rates. Velvetleaf control was greater than 96% with all treatments. Common cocklebur control was 90% or higher with all treatments except a single application of glyphosate at 210 g/ha. Lower control of giant foxtail and common waterhemp with single-application, reduced-rate treatments in two of the four trials resulted in lower yields. Overall, sequential applications, regardless of rate, provided greater weed control, yield, and net income and lower coefficients of variation (C.V.s) of net income than reduced-rate single applications. Single-application treatments showed a trend of decreased weed control, yield, and net income and higher C.V.s of net income with reduced rates of glyphosate.

In-Row and Between-Row Interference by Corn Modifies Annual Weed Control by Preemergence Residual Herbicide

2004 ◽  
Vol 18 (3) ◽  
pp. 497-504 ◽  
Author(s):  
William W. Donald ◽  
William G. Johnson ◽  
Kelly A. Nelson
Keyword(s):  
Corn Yield ◽  
Least Squares Regression ◽  
Row Crops ◽  
Common Waterhemp ◽  
Field Corn ◽  
Giant Foxtail ◽  
Data Variability ◽  
Residual Herbicide ◽  
The Impact ◽  
Dose Dependent

The presence of row crops, such as field corn, improves herbicidal control of weeds, but the impact of crop row position on herbicide dose–response relationships for weeds is unknown. At midseason at three site-years in Missouri, total weed cover (WC) was reduced by increasing soil residual herbicide rate in a dose-dependent response and was as much as 20% lower in-row (IR) than between-row (BR). Preemergence atrazine +S-metolachlor + clopyralid + flumetsulam at different rates (0×, 0.25×, 0.5×, 0.75×, and 1×, where 1× rate was 2,240 + 1,750 + 210 + 67 g ai/ha, respectively) were applied at planting in field corn to control giant foxtail, the chief weed present, and annual broadleaf weeds, largely common waterhemp. Lower herbicide rates were required to reduce IR WC to the same extent as BR WC, but these rates varied between site-years. At all three site-years, a least squares regression equation adequately described data variability relating corn yield to IR or BR WC (or both) (i.e., Y = a + bBR2, where Y is corn yield in kg/ha, BR is BR WC [%], and a and b are coefficients).

Potassium Phosphite Mixed with Other Fungicides Reduces Yield Loss to Downy Mildew on Collard

2010 ◽  
Vol 11 (1) ◽  
pp. 10
Author(s):  
Anthony P. Keinath
Keyword(s):  
Downy Mildew ◽  
Yield Loss ◽  
Control Strategies ◽  
Southeastern United States ◽  
Production Costs ◽  
Water Control ◽  
Economic Return ◽  
Potassium Phosphite ◽  
Full Rate ◽  
Reduced Rate

Downy mildew of collard occurs frequently in the southeastern United States, and fungicides have become an essential part of economical control strategies for the disease. Fungicides were evaluated in 2007 and 2008 either alone or combined with a reduced rate (2 pt/acre) of potassium phosphite. Two formulations of potassium phosphite also were tested alone at the full rate (4 pt/acre). Presidio, Presidio plus Pro-Phyt (2007) or K-Phite (2008), K-Phite, Amistar plus ProPhyt, and Aliette reduced downy mildew severity at the final rating and also reduced AUDPC over the two years. Presidio plus potassium phosphite and Amistar plus ProPhyt increased the weight of healthy leaves and stems over the water control and also increased economic return calculated after fungicide and other production costs were subtracted from the crop value. The yields with Ranman, Sonata, and Presidio applied in combination with potassium phosphite were 16% greater than with the fungicides applied alone. Potassium phosphite may be useful in a tank-mix with other fungicides applied to collard to prevent yield loss to downy mildew. Accepted for publication 7 July 2010. Published 23 August 2010.

Using Estimates of Weed Pressure to Establish Crop Yield Loss Equations

1994 ◽  
Vol 8 (1) ◽  
pp. 114-118 ◽  
Author(s):  
R. Gordon Harvey ◽  
Clark R. Wagner
Keyword(s):  
Linear Regression ◽  
Crop Yield ◽  
Yield Loss ◽  
Sweet Corn ◽  
Crop Yields ◽  
Yield Reduction ◽  
Weed Species ◽  
Field Corn ◽  
Efficacy Trials ◽  
Total Crop

Herbicide efficacy trials in field corn, sweet corn, and soybean were conducted at three locations in Wisconsin over a 6-yr period. Percent weed pressure (WP) was determined by visually estimating the contribution of all weed species present to the total crop and weed volume in each plot. Crop yields in each plot were measured. Percent crop yield reduction (YLDRED) was calculated by comparing mean yields of individual treatments with those of the highest yielding treatment in each trial. Linear regression analyses of YLDRED and WP data from 1640 field corn and 138 sweet corn treatments were significant. Nonlinear regression analysis of YLDRED and WP data from all 1374 soybean treatments was significant; however, a linear regression of those 1154 soybean treatments with WP ratings of 30 or less produced a more easily interpreted regression equation.

Annual Weed Control by Glyphosate in Glyphosate-Resistant Soybean (Glycine max)

1999 ◽  
Vol 13 (2) ◽  
pp. 394-398 ◽  
Author(s):  
Comfort M. Ateh ◽  
Robert G. Harvey
Keyword(s):  
Glycine Max ◽  
Weed Control ◽  
Herbicide Application ◽  
Soybean Yield ◽  
Common Lambsquarters ◽  
Giant Foxtail

Control of natural infestations of common lambsquarters and giant foxtail in 1993, 1994, and 1995 and of velvetleaf in 1994 and 1995 by postemergence application of glyphosate to glyphosate-resistant soybean planted in narrow (20 cm) and wide (76 cm) rows was evaluated. Planting glyphosate-resistant soybean in narrow rows and applying reduced rates of glyphosate when common lambsquarters, giant foxtail, and velvetleaf were at their actively growing stage 3 to 18 cm, 5 to 28 cm, and 3 to 20 cm tall, respectively, resulted in > 90% control. The effect of time of herbicide application was greater than the rate of herbicide application, especially within the wide-row soybean plantings. Applying imazethapyr in combination with glyphosate did not improve weed control or soybean yield compared with glyphosate alone.

scholarly journals Management Options and Factors Affecting Control of a Common Waterhemp (Amaranthus rudis) Biotype Resistant to Protoporphyrinogen Oxidase-Inhibiting Herbicides

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
Dana B. Harder ◽  
Kelly A. Nelson ◽  
Reid J. Smeda
Keyword(s):  
Herbicide Resistance ◽  
Herbicide Application ◽  
Management Options ◽  
Protoporphyrinogen Oxidase ◽  
Factors Affecting ◽  
Common Waterhemp ◽  
Control Options ◽  
Amaranthus Rudis ◽  
Repeated Use ◽  
Herbicide Activity

Repeated use of protox-inhibiting herbicides has resulted in a common waterhemp (Amaranthus rudisSauer) biotype that survived lactofen applied up to 10 times the labeled rate. Field and greenhouse research evaluated control options for this biotype of common waterhemp. In the field, PRE applications of flumioxazin at 72 g ai ha−1, sulfentrazone at 240 g ai ha−1, and isoxaflutole at 70 g ai ha−1controlled common waterhemp >90% up to 6 weeks after treatment. POST applications of fomesafen at 330 g ai ha−1, lactofen at 220 g ai ha−1, and acifluorfen at 420 g ai ha−1resulted in <60% visual control of common waterhemp, but differences were detected among herbicides. In the greenhouse, glyphosate was the only herbicide that controlled protox resistant waterhemp. The majority of herbicide activity from POST flumioxazin, fomesafen, acifluorfen, and lactofen was from foliar placement, but control was less than 40% regardless of placement. Control of common waterhemp seeded at weekly intervals after herbicide treatment with flumioxazin, fomesafen, sulfentrazone, atrazine, and isoxaflutole exceeded 85% at 0 weeks after herbicide application (WAHA), while control with isoxaflutole was greater than 60% 6 WAHA. PRE and POST options for protox-resistant common waterhemp are available to manage herbicide resistance.

Effects of Giant Foxtail (Setaria faberi) and Yellow Foxtail (Setaria pumila) Competition on Establishment and Productivity of Switchgrass

Weed Science ◽  
2016 ◽  
Vol 64 (1) ◽  
pp. 129-136 ◽  
Author(s):  
Ariel A. D. Larson ◽  
Mark J. Renz ◽  
David E. Stoltenberg
Keyword(s):  
Competitive Ability ◽  
Yield Loss ◽  
Annual Grass ◽  
Weed Species ◽  
Setaria Faberi ◽  
Giant Foxtail ◽  
Plant Densities ◽  
Second Year ◽  
Cellulosic Bioenergy ◽  
The Relationship

Switchgrass is a potential feedstock for cellulosic bioenergy production. Weed competition from annual grass during the establishment year can reduce switchgrass establishment and resulting productivity, but the relationship between early season grass densities and outcomes of competition are not well understood. We measured how a range of giant and yellow foxtail densities in the establishment year influenced switchgrass establishment and resulting productivity in the first production year (second year of the growing season). In two of the three site–yr more than four foxtail plants m−2reduced switchgrass plant densities below documented thresholds of establishment success. A lesser effect of foxtails in the third site–year suggested that higher switchgrass emergence rates reduced foxtail competitive ability during establishment. Effects on yield were consistent over the three site–yr. The yield (10.96 Mg ha−1± 0.77) decreased rapidly as foxtail density increased. One foxtail plant m−2reduced switchgrass yield in the first production year by 25%, and yield loss was 90% or greater at densities > 50 foxtail plants m−2. Although switchgrass can establish in the presence of foxtail competition, these weed species should be controlled to maximize yields in the first production year.

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