Velvetleaf (Abutilon theophrasti) Competition and Economic Thresholds in Conventional- and No-Tillage Corn (Zea mays)

Weed Science ◽  
1995 ◽  
Vol 43 (1) ◽  
pp. 81-87 ◽  
Author(s):  
John Cardina ◽  
Emilie Regnier ◽  
Denise Sparrow
Keyword(s):  
Seed Production ◽  
Yield Loss ◽  
Conventional Tillage ◽  
Hyperbolic Function ◽  
Yield Reduction ◽  
Corn Yield ◽  
No Tillage ◽  
Economic Threshold ◽  
Growing Seasons ◽  
Economic Thresholds

Studies were conducted in conventional and no-tillage corn in 1990, 1991, and 1992 at Wooster, OH, to measure corn yield and velvetleaf seed production in response to density of early and late emerging velvetleaf, and to estimate economic thresholds. The percent reduction in corn yield fit a hyperbolic function over velvetleaf densities from 1 to 30 plants m2. The percent yield loss and velvetleaf seed production were higher in a warm, wet year (1990) than in a dry (1991) or cold, wet year (1992). The percent corn yield reduction was generally greater in no-tillage than in conventional tillage and from early rather than late emerging velvetleaf. Maximum velvetleaf seed production ranged from about 18,000 seeds m2for early emerging weeds in no-tillage in 1990 to 100 seeds m2for late emerging weeds in no-tillage in 1992. The single year economic threshold for early emerging velvetleaf ranged from 0.40 to 14.0 velvetleaf m2in conventional tillage and 0.13 to 3.13 in no-tillage. Economic thresholds that were predicted using yield goal information deviated from actual thresholds (using actual yields) for a given year by −43 to 30%. Single year economic thresholds were similar in both tillage treatments, but their value for management decisions is questionable due to variation among growing seasons and weed seed production from subthreshold populations.

Velvetleaf (Abutilon theophrasti) Interference and Seed Production in Corn Silage and Grain

2004 ◽  
Vol 18 (3) ◽  
pp. 779-783 ◽  
Author(s):  
Edward L. Werner ◽  
William S. Curran ◽  
Jayson K. Harper ◽  
Gregory W. Roth ◽  
Daniel P. Knievel
Keyword(s):  
Grain Yield ◽  
Seed Production ◽  
Maximum Yield ◽  
Corn Silage ◽  
Yield Reduction ◽  
Corn Yield ◽  
Yield Model ◽  
Economic Thresholds ◽  
To Come ◽  
Corn Grain

Studies were conducted during a 2-yr period measuring corn silage and grain yield and velvetleaf seed production in response to velvetleaf density. Velvetleaf densities of 0, 2, 5, 10, and 21 plants/m2were established in conventionally tilled corn. The percent corn yield reduction in response to velvetleaf density was similar for both years despite differences in total corn yield. Corn grain and silage yield responded differently to velvetleaf interference. Although both were adversely affected, silage yield reductions were twice that of grain at the low velvetleaf densities. A hyperbolic yield model predicted a maximum yield loss for corn silage and grain of 36 and 37% with incremental losses of 7 and 3%, respectively, as velvetleaf density increased. Velvetleaf seed production ranged from 2,256 to 4,844 seed/m2from the lowest to the highest density. This study demonstrates that corn silage yield is more sensitive than corn grain yield to velvetleaf interference, as well as how crop value plays an important role in determining economic thresholds. Finally, this research confirms the prolific nature of velvetleaf and shows that even at low densities, velvetleaf seed production could affect weed control decisions for many seasons to come.

scholarly journals Modelling the Economics of Controlling Nodding Broomrape (Orobanche cernua) in Sunflower (Helianthus annuus)

Weed Science ◽  
1996 ◽  
Vol 44 (3) ◽  
pp. 591-595 ◽  
Author(s):  
L. García-Torres ◽  
M. Castejón-Muñoz ◽  
M. Jurado-Expósito ◽  
F. López-Granados
Keyword(s):  
Helianthus Annuus ◽  
Crop Yield ◽  
Treatment Cost ◽  
Yield Loss ◽  
Field Studies ◽  
Control Treatment ◽  
Yield Reduction ◽  
Economic Threshold ◽  
Economic Thresholds ◽  
Crop Yield Loss

Field studies were conducted at nine locations in southern Spain during 2 yr to develop models of nodding broomrape competition with sunflower and to establish economic thresholds. At each location, 30 to 35 small plots, each consisting of three sunflower plants, were chosen at random. The infection severity (BIS, no. of emerged broomrapes per sunflower plant) varied from 0 to 35. Plots were harvested at maturity to assess several sunflower and broomrape population variables. The percent sunflower yield reduction averaged over locations due to broomrape was estimated by the equation: % SYR = 1.7 x BIS (r2= 0.92). Crop yield loss per BIS unit increased with the expected yield and was estimated to be about 25, 50, and 75 kg ha−1for yields of 1000, 2000, and 3000 kg ha−1, respectively. A consistent relationship could be established between broomrape-infected sunflower yield, crop and broomrape biomass, and BIS parameters: SSYI= 0.2259 x PoBio/(1 + 0.0687 x BIS) (r2= 0.7820). The BIS economic threshold was about 1.5 and 3.5 for control treatment cost of $ 40 ha−1and potential yields of 2000 and 1000 kg ha−1, respectively.

Case History for Weed Competition/Population Ecology: Barnyardgrass (Echinochloa crus-galli) in Sugarbeets (Beta vulgaris)

1992 ◽  
Vol 6 (1) ◽  
pp. 220-227 ◽  
Author(s):  
Robert F. Norris
Keyword(s):  
Yield Loss ◽  
Management Practice ◽  
Hyperbolic Function ◽  
Weed Competition ◽  
Threshold Density ◽  
Root Yield ◽  
Economic Threshold ◽  
Economic Thresholds ◽  
Sound Management ◽  
The Relationship

Barnyardgrass at 10 or more plants per 1 m of row caused over 80% root yield loss in spring-sown sugarbeets in California. The yield loss decreased to between 5 and 20% when barnyardgrass densities were one plant ever 2 to 3 m of crop row. The relationship between crop yield and barnyardgrass density was described by a rectangular hyperbolic function. The economic threshold density was in the range of one barnyardgrass plant every 5 to 20 m or row. Barnyardgrass plants growing at densities of less than one plant per 1 m in sugarbeets experienced only interspecific competition. Such individual barnyardgrass plants were estimated to produce from 30 000 to over 200 000 seeds, with an average of 100 000 seeds per plant. This seed production equated to a seed rain of about 4000 to nearly 20 000 seeds per m from a density of one weed every 10 m of crop row. These data suggest that using single-year economic thresholds for barnyardgrass is not a sound management practice because even low densities can produce large quantities of seed.

scholarly journals Corn Yield Loss Due to Volunteer Soybean

Weed Science ◽  
2016 ◽  
Vol 64 (3) ◽  
pp. 495-500 ◽  
Author(s):  
Jill Alms ◽  
Sharon A. Clay ◽  
David Vos ◽  
Michael Moechnig
Keyword(s):  
Loss Function ◽  
Growth Stage ◽  
Yield Loss ◽  
Corn Yield ◽  
Yield Losses ◽  
Herbicide Resistant ◽  
Growing Seasons ◽  
Previous Season ◽  
Control Volunteer ◽  
Soybean Plants

The widespread adoption of glyphosate-resistant corn and soybean in cropping rotations often results in volunteer plants from the previous season becoming problem weeds that require alternative herbicides for control. Corn yield losses due to season-long volunteer soybean competition at several densities in two growing seasons were used to define a hyperbolic yield loss function. The maximum corn yield loss observed at high volunteer soybean densities was about 56%, whereas, the incremental yield loss (I) at low densities was 3.2%. Corn yield loss at low volunteer soybean densities was similar to losses reported for low densities of velvetleaf and redroot pigweed, with 10% yield loss estimated to occur at 3 to 4 volunteer soybean plants m−2. Several herbicides, including dicamba with or without diflufenzopyr applied at the V2 growth stage of volunteer soybean, provided > 90% control, demonstrating several economical options to control volunteer glyphosate-resistant soybean in glyphosate-resistant corn. Reevaluation of control recommendations may be needed with commercialization of other genetically modified herbicide-resistant soybean varieties.

Economic and interference threshold densities of quackgrass (Elytrigia repens) in potato (Solanum tuberosum)

Weed Science ◽  
1998 ◽  
Vol 46 (2) ◽  
pp. 176-180 ◽  
Author(s):  
Régis Baziramakenga ◽  
Gilles D. Leroux
Keyword(s):  
Yield Loss ◽  
Dry Weight ◽  
Field Studies ◽  
Potato Yield ◽  
Hyperbolic Function ◽  
Yield Losses ◽  
Economic Threshold ◽  
Elytrigia Repens ◽  
Shoot Number ◽  
Dry Biomass

Field studies were conducted in 1989 and 1990 at St-Augustin, Quebec, Canada, to determine the economic threshold density of quackgrass in potato. Potato yield losses due to quackgrass interference increased with quackgrass population density. Potato yield ranged from 33 to 73% in 1989, and from 19 to 44% in 1990. The relationship between potato yield losses and quackgrass densities was described by a rectangular hyperbolic function. Dry weight of quackgrass proved to be the best predictor of potato yield loss compared to shoot number. The interference thresholds for 10% potato yield loss amounted to 25 shoots m−2or 20 g total dry biomass m−2. The economic threshold varied between 0.04 and 2 shoots m−2or 0.0165 and 1.5 g total dry biomass m−2, depending on the variables considered.

Effect of pH, Nitrogen, and Tillage on Weed Control and Corn (Zea mays) Yield

Weed Science ◽  
1980 ◽  
Vol 28 (6) ◽  
pp. 719-722 ◽  
Author(s):  
J. J. Kells ◽  
R. L. Blevins ◽  
C. E. Rieck ◽  
W. M. Muir
Keyword(s):  
Zea Mays ◽  
Weed Control ◽  
Soil Ph ◽  
Soil Surface ◽  
Field Studies ◽  
Conventional Tillage ◽  
Corn Yield ◽  
No Tillage ◽  
Linear Effect ◽  
Surface Soil Ph

Field studies were conducted to determine the effect of soil surface (upper 5 cm) pH and tillage on weed control and corn (Zea maysL.) yield using simazine [2-chloro-4,6-bis-(ethylamino)-s-triazine] as the herbicide for weed control. Soil pH, weed control, and corn yield were examined under no-tillage and conventional tillage systems with and without added lime and different rates of nitrogen. Increased soil pH significantly increased weed control as compared with added lime vs. no added lime, where the surface soil pH influenced the effectiveness of the applied simazine. Soil pH had a greater effect on weed control under no-tillage than under conventional tillage. Conventional tillage significantly (P<.01) increased weed control, yield, and soil pH over no-tillage. Additions of lime as compared to unlimed treatments resulted in significantly increased weed control (83% vs. 63%), yield (5,930 vs. 5,290 kg/ha) and soil pH (5.91 vs. 5.22). The poorest weed control was observed with no-tillage on unlimed plots. A significant tillage by linear effect of nitrogen interaction for all variables resulted from a greater decrease (P<.01) in weed control and soil pH and a greater increase in yield with increased nitrogen under no-tillage than with conventional tillage.

Downy Brome (Bromus tectorum) Interference and Economic Thresholds in Winter Wheat (Triticum aestivum)

Weed Science ◽  
1990 ◽  
Vol 38 (3) ◽  
pp. 224-228 ◽  
Author(s):  
Phillip W. Stahlman ◽  
Stephen D. Miller
Keyword(s):  
Winter Wheat ◽  
Bromus Tectorum ◽  
Yield Loss ◽  
Wheat Yield ◽  
Dry Weight ◽  
Quadratic Equation ◽  
Downy Brome ◽  
Economic Threshold ◽  
Weed Density ◽  
Economic Thresholds

Densities up to 100 downy brome m2were established in winter wheat in southeastern Wyoming and west-central Kansas to quantify wheat yield loss from downy brome interference and to approximate economic threshold levels. A quadratic equation best described wheat yield loss as a function of weed density when downy brome emerged within 14 days after wheat emergence. Densities of 24, 40, and 65 downy brome m2reduced wheat yield by 10, 15, and 20%, respectively. Wheat yield was not reduced when downy brome emerged 21 or more days later than wheat. Economic thresholds varied with changes in downy brome density, cost of control, wheat price, and potential wheat yield. In a greenhouse experiment, dry weight of 72-day-old wheat plants grown in association with downy brome was not affected by the distance between the weeds and wheat, whereas downy brome plant dry weight increased with increasing distance between the weeds and wheat.

Shattercane (Sorghum bicolor) Interference in Soybean (Glycine max)

Weed Science ◽  
1992 ◽  
Vol 40 (1) ◽  
pp. 68-73 ◽  
Author(s):  
Gary M. Fellows ◽  
Fred W. Roeth
Keyword(s):  
Glycine Max ◽  
Plant Height ◽  
Direct Relationship ◽  
Yield Loss ◽  
Economic Loss ◽  
Hyperbolic Function ◽  
Yield Reduction ◽  
Soybean Plant ◽  
Soybean Yield ◽  
Forage Sorghum

Shattercane interference in irrigated soybean was evaluated during 1987, 1988, and 1989 at Clay Center, NE, using ‘Rox’ forage sorghum to simulate shattercane. Soybean yield reduction did not occur if shattercane was removed by 2 wk after emergence in 1987 and 6 wk after emergence in 1988 and 1989. Shattercane interference with soybean began when shattercane height exceeded soybean height. Soybean yield was reduced up to 25% before the height differential reached 30 cm, the minimum difference required for selectively applying glyphosate with a wiper applicator. Soybean nodes per stem, pods per stem, and beans per pod decreased as duration of interference increased. A direct relationship between soybean yield loss and shattercane density fit a rectangular hyperbolic function. Yield loss per shattercane plant was highest at low shattercane densities. Soybean plant height, biomass, nodes per stem, pods per stem, pods per node, and beans per pod decreased as shattercane density increased. An interference model for estimation of soybean yield and economic loss based on shattercane density was developed.

Velvetleaf (Abutilon theophrasti) Effect on Corn (Zea mays) Growth and Yield in South Dakota

1995 ◽  
Vol 9 (4) ◽  
pp. 665-668 ◽  
Author(s):  
Chad Scholes ◽  
Sharon A. Clay ◽  
Kalyn Brix-Davis
Keyword(s):  
South Dakota ◽  
Yield Loss ◽  
Maximum Yield ◽  
Abutilon Theophrasti ◽  
Growth And Yield ◽  
Yield Reduction ◽  
Corn Yield ◽  
Total Biomass ◽  
Area Index ◽  
Large Yield

Studies were conducted at two sites in South Dakota in 1992 and at one site in 1993 to measure the effect of velvetleaf on corn growth and yield. Velvetleaf was overseeded in corn rows and thinned to densities of 0, 1.3, 4, 12, and 24 plants/m2. Velvetleaf leaf area index and total biomass were positively correlated with velvetleaf density. Biomass per velvetleaf plant and corn biomass were correlated negatively with velvetleaf density. The percent corn yield reduction was similar for locations and years in spite of large yield differences. Maximum yield loss estimated by a hyperbolic yield reduction model was 37.2% with a loss of 4.4% per unit velvetleaf density.

scholarly journals Soil health indicators after 21 yr of no-tillage in south coastal British Columbia

2019 ◽  
Vol 99 (2) ◽  
pp. 222-225
Author(s):  
Ben W. Thomas ◽  
Derek Hunt ◽  
Shabtai Bittman ◽  
Kirsten D. Hannam ◽  
Aimé J. Messiga ◽  
...  
Keyword(s):  
Soil Layer ◽  
Soil Health ◽  
Aggregate Stability ◽  
Health Indicators ◽  
Conventional Tillage ◽  
No Tillage ◽  
Growing Seasons ◽  
No Till ◽  
Wet Aggregate Stability ◽  
Fraser Valley

The lower Fraser Valley is one of the most intensively cropped regions in Canada. Yet, how soil health indicators respond to long-term intensive agricultural management is poorly documented in this region. Thus, we evaluated a suite of soil health indicators in response to 21 growing seasons of continuous silage corn (Zea mays L.) under conventional tillage or no-tillage (0–20 cm soil layer). Wet aggregate stability, available water capacity, active carbon (permanganate oxidizable, POXC), and extractable potassium and extractable magnesium were significantly greater with no-till than conventional tillage, whereas 8 of 13 indicators were similar. Soil health indicators responded more favourably to no-till than conventional tillage.

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