Evaluating the Potential for Site-Specific Herbicide Application in Soybean

2004 ◽  
Vol 18 (4) ◽  
pp. 1101-1110 ◽  
Author(s):  
Gail G. Wilkerson ◽  
Andrew J. Price ◽  
Andrew C. Bennett ◽  
David W. Krueger ◽  
Gary T. Roberson ◽  
...  
Keyword(s):  
Weed Management ◽  
Yield Loss ◽  
Grid Cell ◽  
Optimal Treatment ◽  
Grid Cells ◽  
Herbicide Application ◽  
Site Specific ◽  
Net Return ◽  
Net Returns ◽  
On Farm

Field experiments were conducted on two North Carolina research stations in 1999, 2000, and 2001; on-farm in Lenoir, Wayne, and Wilson counties, NC, in 2002; and on-farm in Port Royal, VA, in 2000, 2001, and 2002 to evaluate possible gains from site-specific herbicide applications at these locations. Fields were scouted for weed populations using custom software on a handheld computer linked to a Global Positioning System. Scouts generated field-specific sampling grids and recorded weed density information for each grid cell. The decision aid HADSS™ (Herbicide Application Decision Support System) was used to estimate expected net return and yield loss remaining after treatment in each sample grid of every field under differing assumptions of weed size and soil moisture conditions, assuming the field was planted with either conventional or glyphosate-resistant (GR) soybean. The optimal whole-field treatment (that treatment with the highest expected net return summed across all grid cells within a field) resulted in average theoretical net returns of $79/ha (U.S. dollars) and $139/ha for conventional and GR soybean, respectively. When the most economical treatment for each grid cell was used in site-specific weed management, theoretical net returns increased by $13/ha (conventional) and $4.50/ha (GR), and expected yield loss after treatment was reduced by 10.5 and 4%, respectively, compared with the whole-field optimal treatment. When the most effective treatment for each grid cell was used in site-specific weed management, theoretical net returns decreased by $18/ha (conventional) and $4/ha (GR), and expected yield loss after treatment was reduced by 27 and 19%, respectively, compared with the whole-field optimal treatment. Site-specific herbicide applications could have reduced the volume of herbicides sprayed by as much as 70% in some situations but increased herbicide amounts in others. On average, the whole-field treatment was optimal in terms of net return for only 35% (conventional) and 57% (GR) of grid cells.

scholarly journals Spatial distribution, temporal stability, and yield loss estimates for annual grasses and common ragweed (Ambrosia artimisiifolia) in a corn/soybean production field over nine years

Weed Science ◽  
2006 ◽  
Vol 54 (02) ◽  
pp. 380-390 ◽  
Author(s):  
Sharon A. Clay ◽  
Bruce Kreutner ◽  
David E. Clay ◽  
Cheryl Reese ◽  
Jonathan Kleinjan ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Weed Management ◽  
Yield Loss ◽  
Temporal Stability ◽  
Grid Cell ◽  
Specific Information ◽  
Common Ragweed ◽  
Soybean Production ◽  
Time Space ◽  
Annual Grasses

Weeds generally occur in patches in production fields. Are these patches spatially and temporally stable? Do management recommendations change on the basis of these data? The population density and location of annual grass weeds and common ragweed were examined in a 65-ha corn/soybean production field from 1995 to 2004. Yearly treatment recommendations were developed from field means, medians, and kriging grid cell densities, using the hyperbolic yield loss (YL) equation and published incremental YL values (I), maximum YL values (A), and YL limits of 5, 10, or 15%. Mean plant densities ranged from 12 to 131 annual grasses m−2and < 1 to 37 common ragweed m−2. Median weed densities ranged from 0 to 40 annual grasses m−2and were 0 for common ragweed. The grassIvalues used to estimate corn YL were 0.1 and 2% and treatment was recommended in only 1 yr when the highIvalue and either the mean or median density was used. The grassIvalues used for soybean were 0.7 and 10% and estimated YL was over 10% all years, regardless ofIvalue. The common ragweedIvalues were 4.5 and 6% for corn and 5.1 and 15.6% for soybean. On the basis of mean densities, fieldwide treatment would have been recommended in 6 of 9 yr but in no years when the median density was used. Recommendations on the basis of grid cell weed density and kriging ranged from > 80% of the field treated for grass weeds in 3 of 4 yr in soybean to < 20% of the field treated for common ragweed in 2002 and 2004 (corn). Grass patches were more stable in time, space, and density than common ragweed patches. Population densities and spatial distribution generally were variable enough so that site-specific information within this field would improve weed management decisions.

scholarly journals Impact of site-specific weed management on herbicide savings and winter wheat yield  

2013 ◽  
Vol 59 (No. 3) ◽  
pp. 101-107 ◽  
Author(s):  
P. Hamouz ◽  
K. Hamouzová ◽  
J. Holec ◽  
L. Tyšer
Keyword(s):  
Winter Wheat ◽  
Weed Management ◽  
Wheat Yield ◽  
The Other ◽  
Herbicide Application ◽  
Site Specific ◽  
Treatment Thresholds ◽  
Patch Spraying ◽  
Winter Wheat Yield ◽  
Weed Infestation

An aggregated distribution pattern of weed populations provides opportunity to reduce the herbicide application if site-specific weed management is adopted. This work is focused on the practical testing of site-specific weed management in a winter wheat and the optimisation of the control thresholds. Patch spraying was applied to an experimental field in Central Bohemia. Total numbers of 512 application cells were arranged into 16 blocks, which allowed the randomisation of four treatments in four replications. Treatment 1 represented blanket spraying and the other treatments differed by the herbicide application thresholds. The weed infestation was estimated immediately before the post-emergence herbicide application. Treatment maps for every weed group were created based on the weed abundance data and relevant treatment thresholds. The herbicides were applied using a sprayer equipped with boom section control. The herbicide savings were calculated for every treatment and the differences in the grain yield between the treatments were tested using the analysis of variance. The site-specific applications provided herbicide savings ranging from 15.6% to 100% according to the herbicide and application threshold used. The differences in yield between the treatments were not statistically significant (P = 0.81). Thus, the yield was not lowered by site-specific weed management.

Bioeconomic Modeling to Simulate Weed Control Strategies for Continuous Corn (Zea mays)

Weed Science ◽  
1986 ◽  
Vol 34 (6) ◽  
pp. 972-979 ◽  
Author(s):  
Robert P. King ◽  
Donald W. Lybecker ◽  
Edward E. Schweizer ◽  
Robert L. Zimdahl
Keyword(s):  
Zea Mays ◽  
Weed Control ◽  
Weed Management ◽  
Management Strategy ◽  
Performance Indicator ◽  
Management Strategies ◽  
Weed Seed ◽  
Net Return ◽  
Net Returns ◽  
Continuous Corn

Grass and broadleaf weed densities and seed numbers, weed control practices, and grain yields were included in a bioeconomic model that evaluates alternative weed management strategies for continuous corn (Zea maysL.). Weed seed numbers in soil and herbicide carry-over provided intertemporal links. Four weed management strategies – two fixed, one mixed, and one flexible – were evaluated with annualized net returns as the performance indicator. The flexible strategy (weed control based on observed conditions) had the largest annualized net return for high and low initial weed seed numbers. The fixed weed management strategy (weed control predetermined) of an annual application of only a preemergence herbicide ranked second in terms of annualized net returns for high weed seed numbers. The mixed weed management strategy of alternative year applications of preemergence herbicide and “as needed” applications of postemergence herbicide ranked second for low initial weed seed numbers. The fixed weed management strategy of alternate year application of preemergence herbicide only generated the lowest annualized net return, regardless of initial weed seed numbers.

Predicted Corn Yield Loss Due to Weed Competition Prior to Postemergence Herbicide Application on Wisconsin Farms

2013 ◽  
Vol 27 (1) ◽  
pp. 54-62 ◽  
Author(s):  
Nathanael D. Fickett ◽  
Chris M. Boerboom ◽  
David E. Stoltenberg
Keyword(s):  
Weed Management ◽  
Yield Loss ◽  
Economic Loss ◽  
The United States ◽  
Yield Potential ◽  
Weed Competition ◽  
Corn Yield ◽  
Herbicide Application ◽  
Weed Species ◽  
Early Season

Approximately 50% of the genetically modified herbicide-resistant corn hectares in the United States are treated only with POST-applied herbicides for weed management. Although a high degree of efficacy can be obtained with POST-applied herbicides, delayed timing of application may result in substantial corn yield loss. Our goal was to characterize on-farm corn–weed communities prior to POST herbicide application and estimate potential corn-yield loss associated with early-season corn–weed competition. In 2008 and 2009, field surveys were conducted across 95 site-years in southern Wisconsin and recorded weed species, density, and height in addition to crop height, growth stage, and row spacing. WeedSOFT® was used to predict corn yield loss. Common lambsquarters, velvetleaf, dandelion, common ragweed, andAmaranthusspecies were the five most abundant broadleaf weed species across site-years, present in 92, 86, 59, 45, and 44% of all fields, respectively, at mean densities of 19, 3, 3, 4, and 3 plants m−2, respectively. Mean plant heights among these species were 17 cm or less. Grass and sedge species occurred in 96% of fields at a mean density of 25 plants m−2and height of 7 cm. The mean and median of total weed density across site-years were 96 and 52 plants m−2, with heights of 14 and 13 cm, respectively. Mean predicted corn yield loss was 4.5% with a mean economic loss of $62 ha−1. However, predicted yield loss was greater than 5% on one-third of the site-years, with a maximum of 26%. These results indicate that delayed application of POST herbicides has led to corn yield loss due to early-season weed-crop competition on a substantial number of fields across southern Wisconsin, and suggest that management tactics need to be improved to protect corn yield potential fully.

Economics and Effectiveness of Alternative Weed Scouting Methods in Peanut

2007 ◽  
Vol 21 (1) ◽  
pp. 88-96 ◽  
Author(s):  
Bridget L. Robinson ◽  
Jodie M. Moffitt ◽  
Gail G. Wilkerson ◽  
David L. Jordan
Keyword(s):  
Field Method ◽  
Optimal Treatment ◽  
Weed Species ◽  
Field Range ◽  
Net Returns ◽  
Count Method ◽  
Average Loss ◽  
Application Decision ◽  
On Farm

On-farm trials were conducted in 16 North Carolina peanut fields to obtain estimates of scouting times and quality of herbicide recommendations for different weed scouting methods. The fields were monitored for weed species and population density using four scouting methods: windshield (estimate made from the edge of the field), whole-field (estimate based on walk through the field), range (weed densities rated on 1–5 scale at six locations in the field), and counts (weeds estimated by counting at six locations in the field). The herbicide application decision support system (HADSS) was used to determine theoretical net return over herbicide investment and yield loss ($ and %) for each treatment in each field. Three scouts estimated average weed population densities using each scouting method. These values were entered into HADSS to obtain treatment recommendations. Independently collected count data from all three scouts were combined to determine the optimal treatment in each field and the relative ranking of each available treatment. When using the whole-field method, scouts observed a greater number of weed species than when using the other methods. The windshield, whole-field, and range scouting methods tended to overestimate density slightly at low densities and underestimate density substantially at high densities, compared to the count method. The windshield method required the least amount of time to complete (6 min per field), but also resulted in the greatest average loss. Even for this method, recommendations had theoretical net returns within 10% of the return for the optimal treatment 80% of the time. The count method appears to have less economic risk than the windshield, whole-field, and range scouting methods.

An on-farm approach to quantify yield variation and to derive decision rules for site-specific weed management

2008 ◽  
Vol 9 (3) ◽  
pp. 133-146 ◽  
Author(s):  
C. Ritter ◽  
D. Dicke ◽  
M. Weis ◽  
H. Oebel ◽  
H. P. Piepho ◽  
...  
Keyword(s):  
Weed Management ◽  
Decision Rules ◽  
Site Specific ◽  
Yield Variation ◽  
On Farm

Spatial Pattern of Weeds Based on Multispecies Infestation Maps Created by Imagery

Weed Science ◽  
2016 ◽  
Vol 64 (3) ◽  
pp. 474-485 ◽  
Author(s):  
Louis Longchamps ◽  
Bernard Panneton ◽  
Robin Reich ◽  
Marie-Josée Simard ◽  
Gilles D. Leroux
Keyword(s):  
Spatial Distribution ◽  
Image Segmentation ◽  
Spatial Pattern ◽  
Weed Management ◽  
Herbicide Application ◽  
Weed Species ◽  
Site Specific ◽  
Weed Cover ◽  
Weed Infestation ◽  
Level Of Aggregation

Weeds are often spatially aggregated in maize fields, and the level of aggregation varies across and within fields. Several annual weed species are present in maize fields before postemergence herbicide application, and herbicides applied will control several species at a time. The goal of this study was to assess the spatial distribution of multispecies weed infestation in maize fields. Ground-based imagery was used to map weed infestations in rain-fed maize fields. Image segmentation was used to extract weed cover information from geocoded images, and an expert-based threshold of 0.102% weed cover was used to generate maps of weed presence/absence. From 19 site-years, 13 (68%) demonstrated a random spatial distribution, whereas six site-years demonstrated an aggregated spatial pattern of either monocotyledons, dicotyledons, or both groups. The results of this study indicated that monocotyledonous and dicotyledonous weed groups were not spatially segregated, but discriminating these weed groups slightly increased the chances of detecting an aggregated pattern. It was concluded that weeds were not always spatially aggregated in maize fields. These findings emphasize the need for techniques allowing the assessment of weed aggregation prior to conducting site-specific weed management.

scholarly journals Effect of site-specific weed management in winter crops on yield and weed populations

2014 ◽  
Vol 60 (No. 1) ◽  
pp. 27-35 ◽  
Author(s):  
P. Hamouz ◽  
K. Hamouzová ◽  
L. Tyšer ◽  
J. Holec
Keyword(s):  
Weed Management ◽  
Standard Treatment ◽  
Species Abundance ◽  
Herbicide Application ◽  
Weed Species ◽  
Site Specific ◽  
Weed Population Dynamics ◽  
Herbicide Treatments ◽  
Weed Infestation ◽  
Winter Crops

Site-specific weed management (SSWM) methods allow spatially variable treatment of weed populations according to actual weed abundance, thus offering the opportunity for herbicide savings. However, SSWM&rsquo;s effect on weed population dynamics is not sufficiently understood. In this study, SSWM was conducted based on various application thresholds to analyse the effects on crop yield and weed infestation in the succeeding crop. SSWM was used on a 3.07 ha experimental field in winter wheat (2011) and winter oilseed rape (2012). The whole area was split into application cells of 6 &times; 10 m and abundance of all weed species was evaluated manually in each cell. Four different herbicide treatments were tested. Standard whole-field herbicide application (blanket spraying) was treatment 1.<br /> Treatments 2, 3 and 4 comprised SSWM using different thresholds for post-emergent herbicide application. SSWM resulted in savings of post-emergent herbicides ranging from 71.9% to 100%, depending on the application threshold. Differences in winter rape yield among treatments were generally small and statistically insignificant<br /> (P = 0.989). Although some minor changes in weed abundances were observable, the experiment showed that none of the site-specific herbicide treatments caused a significant (&alpha; = 0.05) increase of weed species abundance compared to the standard treatment.

scholarly journals Impact of site-specific weed management in winter crops on weed populations

2014 ◽  
Vol 60 (No. 11) ◽  
pp. 518-524 ◽  
Author(s):  
P. Hamouz ◽  
K. Hamouzová ◽  
J. Holec ◽  
L. Tyšer
Keyword(s):  
Weed Management ◽  
Soil Seed Bank ◽  
Correlation Coefficients ◽  
Herbicide Application ◽  
Winter Oilseed Rape ◽  
Site Specific ◽  
Galium Aparine ◽  
Plant Densities ◽  
Winter Crops

This work is focused on evaluating the effects of site-specific weed management (SSWM) on weed populations over a 4-year period. SSWM was used on a 3.07 ha experimental field during 2011&ndash;2014 in a rotation of winter wheat and winter oilseed rape. The area was split into application cells of 6 &times; 10 m and weed abundance was evaluated manually in each cell. Four different herbicide treatments were tested. Standard whole-field herbicide application (blanket spraying) was treatment 1. Treatments 2, 3 and 4 comprised SSWM using different thresholds for post-emergent herbicide applications. SSWM resulted in herbicide savings of 6.3&ndash;100% for Galium aparine, 0&ndash;84.4% for other dicotyledonous weeds, and 31.3&ndash;90.6% for annual monocotyledonous weeds. SSWM led to significantly increased density of G. aparine and Tripleurospermum inodorum in the final experimental year when compared to the blanket treatment. Negative correlation coefficients between 2011 and 2014 plant densities found in SSWM treatments (&minus;0.237 to &minus;0.401) indicate that Apera spica-venti does not establish a long-term soil seed bank.

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