Common sunflower (Helianthus annuus) and shattercane (Sorghum bicolor) interference in corn

Weed Science ◽  
2004 ◽  
Vol 52 (6) ◽  
pp. 976-983 ◽  
Author(s):  
Stephanie R. Deines ◽  
J. Anita Dille ◽  
Eric L. Blinka ◽  
David L. Regehr ◽  
Scott A. Staggenborg
Keyword(s):  
Field Experiments ◽  
Yield Loss ◽  
Additive Model ◽  
Initial Slope ◽  
Corn Yield ◽  
Yield Losses ◽  
Weed Species ◽  
Loss Model ◽  
Rectangular Hyperbola ◽  
Multiple Species

Multiple weed species in the field combine to cause yield losses and can be described using one of several empirical models. Field studies were conducted to compare observed corn yield loss caused by common sunflower and shattercane populations with predicted yield losses modeled using a multiple species rectangular hyperbola model, an additive model, or the yield loss model in the decision support system, WeedSOFT, and to derive competitive indices for common sunflower and shattercane. Common sunflower and shattercane emerged with corn and selected densities established in field experiments at Scandia and Rossville, KS, between 2000 and 2002. The multiple species rectangular hyperbola model fit pooled data from three of five location–years with a predicted maximum corn yield loss of 60%. Initial slope parameter estimate for common sunflower was 49.2 and 4.2% for shattercane. A ratio of these estimates indicated that common sunflower was 11 times more competitive than shattercane. When common sunflower was assigned a competitive index (CI) value of 10, shattercane CI was 0.9. Predicted yield losses modeled for separate common sunflower or shattercane populations were additive when compared with observed yield losses caused by low-density mixed populations of common sunflower (0 to 0.5 plants m−2) and shattercane (0 to 4 plants m−2). However, a ratio of estimates of these models indicated that common sunflower was only four times as competitive as shattercane, with a CI of 2.5 for shattercane. The yield loss model in WeedSOFT underpredicted the same corn losses by 7.5%. Clearly, both the CI for shattercane and the yield loss model in WeedSOFT need to be reevaluated, and the multiple species rectangular hyperbola model is proposed.

Effects of hybrid susceptibility and inoculation timing on Goss’s bacterial wilt and leaf blight severity and corn yield

Plant Disease ◽  
2021 ◽  
Author(s):  
Elizabeth C Bauske ◽  
Andrew J Friskop
Keyword(s):  
Disease Severity ◽  
Bacterial Wilt ◽  
Field Experiments ◽  
Yield Loss ◽  
Leaf Blight ◽  
Corn Yield ◽  
Yield Losses ◽  
Sequential Combination ◽  
High Level ◽  
Growing Region

Goss’s bacterial wilt and leaf blight (Goss’s wilt) of corn is the most important corn disease in North Dakota (ND), and yield loss due to the disease has not been reliably quantified in northern corn growing regions. To help quantify the amount of yield loss caused by Goss’s wilt, a total of six field experiments were conducted from 2015 to 2017. Experiments were designed in a randomized complete block with a split plot arrangement. Hybrids served as main plots and Clavibacter nebraskensis (Cn) inoculation timings as sub-plots. Three hybrids were used and classified as a susceptible, moderately susceptible, and resistant. Inoculation timings included a non-inoculated control, six to ten leaf collars (V6 to V10), reproductive silk stage (R1), or a sequential combination of V6 to V10 and R1. A high level of disease (greater than 50% on susceptible hybrid) occurred in three experiments, a low level of disease (less than 5% on susceptible hybrid) in one experiment, and no disease was reported in two experiments. A combined analysis of the high disease experiments indicated yield losses of 34 to 41% on the susceptible hybrid when Cn inoculation occurred at V6 to V10. Yield losses of 22 to 25% occurred on the moderately susceptible hybrid when C. nebraskensis inoculation occurred at V6 to V10, and statistical differences in yield loss were not found among inoculations timings on the resistant hybrid. Correlation analyses suggest that for every 1% increase in R1 disease severity on the susceptible hybrid, yield was reduced by 117 kg/ha (1.9 bu/A). The current study further demonstrates the importance of hybrid resistance and provides updated yield loss information on Goss’s wilt in a northern corn growing region.

Functional relationships between giant ragweed (Ambrosia trifida) interference and sweet corn yield and ear traits

Weed Science ◽  
2006 ◽  
Vol 54 (5) ◽  
pp. 948-953 ◽  
Author(s):  
Martin M. Williams ◽  
John B. Masiunas
Keyword(s):  
Field Experiments ◽  
Yield Loss ◽  
Sweet Corn ◽  
Initial Slope ◽  
Hyperbolic Model ◽  
Corn Yield ◽  
Fresh Market ◽  
Ambrosia Trifida ◽  
Functional Relationships ◽  
Giant Ragweed

Field experiments were conducted to quantify functional relationships between giant ragweed density and sweet corn yield and ear traits. A rectangular hyperbolic model was fit to yield loss measured in terms of marketable ear mass, appropriate for the processing industry, and boxes of 50 marketable ears, relevant to the fresh market industry. The initial slope of the hyperbolic yield loss function (I), which describes the linear portion of yield loss as weed density (weeds per square meter) approaches zero, was 119 for loss of ear mass and 97 for loss of boxes of ears. Furthermore, 10 of 12 ear traits including green ear mass, husked ear mass, ear length, filled ear length, ear width, number of kernels per row, number of rows, kernel depth, kernel mass, and kernel moisture content were significantly affected by giant ragweed interference.

Influence of Cotton (Gossypium hirsutum) and Soybean (Glycine max) Planting Date on Weed Interference

Weed Science ◽  
1994 ◽  
Vol 42 (1) ◽  
pp. 61-65 ◽  
Author(s):  
Tracy E. Klingaman ◽  
Lawrence R. Oliver
Keyword(s):  
Field Experiments ◽  
Yield Loss ◽  
Planting Date ◽  
Cotton Yield ◽  
Yield Losses ◽  
Seed Cotton ◽  
Weed Species ◽  
Planting Dates ◽  
Seed Cotton Yield ◽  
Weed Interference

Separate field experiments were conducted for cotton and soybean in 1990 and 1991 to determine the influence of planting date on yield loss due to interspecific interference from entireleaf morningglory and sicklepod and to determine the relative competitiveness of each weed species. Percent soybean yield loss due to weed interference increased as planting date was delayed from early May to early June. Averaged over weed species, yield losses from 1.7 weeds m−1row were 10, 18, and 20% for soybeans planted in early May, mid-May, and early June, respectively. Yield loss from 6.7 weeds m−1row were 17, 31, and 35% at the early May, mid-May, and early June planting dates, respectively. Percent seed cotton yield losses averaged over weed species in 1990 were 33 and 28% for the early May and early June planting dates, respectively, at 1.7 weeds m−1and 50% for both planting dates at weed densities of 6.7 plants m−1. The only experimental factor that significantly affected seed cotton yield in 1991 was weed density. Unlike soybeans, planting date had little effect on weed interference in cotton. Entireleaf morningglory was more competitive than sicklepod in both crops. Results suggest that selection of optimum soy bean planting dates may be a viable means of reducing losses due to weed interference.

scholarly journals Wheat Yield Loss in a Two Species Competition with Emex australis and Emex spinosa

2016 ◽  
Vol 34 (1) ◽  
pp. 35-46 ◽  
Author(s):  
M.M. JAVAID ◽  
A. TANVEER ◽  
H.H. ALI ◽  
M.A. SHAHID ◽  
R.M. BALAL ◽  
...  
Keyword(s):  
Yield Components ◽  
Field Experiments ◽  
Yield Loss ◽  
Maximum Yield ◽  
Wheat Yield ◽  
Growth And Yield ◽  
Wheat Crop ◽  
Yield Losses ◽  
Weed Species ◽  
Emex Australis

Emex australis and E. spinosa are significant weed species in wheat and other crops. Information on the extent of competition of the Emex species will be helpful to access yield losses in wheat. Field experiments were conducted to quantify the interference of tested weed densities each as single or mixture of both at 1:1 on their growth and yield, wheat yield components and wheat grain yield losses in two consecutive years. Dry weight of both weed species increased from 3-6 g m-2 with every additional plant of weed, whereas seed number and weight per plant decreased with increasing density of either weed. Both weed species caused considerable decrease in yield components like spike bearing tillers, number of grains per spike, 1000-grain weight of wheat with increasing density population of the weeds. Based on non-linear hyperbolic regression model equation, maximum yield loss at asymptotic weed density was estimated to be 44 and 62% with E. australis, 56 and 70% with E. spinosa and 63 and 72% with mixture of both species at 1:1 during both year of study, respectively. It was concluded that E. spinosa has more competition effects on wheat crop as compared to E. australis.

scholarly journals The impact of cultivar resistance and fungicide treatment on mycotoxin content in grain and yield losses caused by Fusarium head blight in wheat

2010 ◽  
Vol 46 (No. 1) ◽  
pp. 21-26 ◽  
Author(s):  
V. Šíp ◽  
J. Chrpová ◽  
O. Veškrna ◽  
L. Bobková
Keyword(s):  
Grain Yield ◽  
Fusarium Head Blight ◽  
Field Experiments ◽  
Yield Loss ◽  
Joint Effect ◽  
Yield Losses ◽  
Cultivar Resistance ◽  
Head Blight ◽  
Fungicide Treatment ◽  
The Impact

Reactions to artificial infection with Fusarium graminearum isolates and a new fungicide Swing Top were studied in nine winter wheat cultivars evaluated in field experiments at two sites for three years for expression of symptoms, deoxynivalenol (DON) content in grain and grain yield. The results demonstrate a pronounced and relatively stable effect of cultivar resistance on reducing head blight, grain yield losses and contamination of grain by the mycotoxin DON. It is advantageous that the moderate level of resistance to Fusarium head blight (FHB) was detected also in two commonly grown Czech cultivars Sakura and Simila. Average fungicide efficacy for DON was 49.5% and 63.9% for a reduction in yield loss, however, it was found highly variable in different years and sites. The joint effect of cultivar resistance and fungicide treatment was 86.5% for DON and even 95.4% for reducing the yield loss. A very high risk was documented for susceptible cultivars and also the effects of medium responsive cultivars were found to be highly variable in different environments and therefore not guaranteeing sufficient protection against FHB under different conditions.

scholarly journals Modeling the Competitive Effect of Euphorbia dracunculoides and Astragalus sp. in Zero Input Rainfed Chickpea

2018 ◽  
Vol 36 (0) ◽  
Author(s):  
R.M. IKRAM ◽  
A. TANVEER ◽  
R. MAQBOOL ◽  
M.A. NADEEN
Keyword(s):  
Protein Content ◽  
Critical Period ◽  
Field Experiments ◽  
Seed Protein ◽  
Yield Loss ◽  
Seed Protein Content ◽  
Yield Losses ◽  
Competition Period ◽  
Crop Competition ◽  
Weed Removal

ABSTRACT: Brown chickpea (Cicer arietinum L.) is one of the two chickpea types grown in Pakistan and other countries. The critical period for weed removal in a rainfed chickpea system is an important consideration in devising weed management strategies. Field experiments were conducted in the winter season of 2011 and 2012 to determine the extent of yield loss with different periods of weed crop competition. Seven weed crop competition periods (0, 45, 60, 75, 90, 105 and 160 days after sowing - DAS) were used to identify the critical period for weed removal in rainfed chickpea. Experimental plots were naturally infested with Euphorbia dracunculoides and Astragalus sp. in both years. Individual, composite density and dry weights of E. dracunculoides and Astragalussp. increased significantly with an increase in the competition period. However, yield and yield-contributing traits of chickpea significantly decreased with an increase in the competition period. Chickpea seed yield loss was 11-53% in different weed crop competition periods. Euphorbia dracunculoides and Astragalus sp. removed 39.9 and 36.9 kg ha-1 of N, 9.61 and 7.27 kg ha-1 of P and 38.3 and 36.9 kg ha-1 of K, respectively. Season long weed competition (160 days after sowing) resulted in 19.5% seed protein content compared with 24.5% seed protein content in weed-free chickpea. A Logistic equation was fitted to yield data in response to increasing periods of weed crop competition. The critical timing of weed removal at 5 and 10% acceptable yield losses were 26 and 39 DAS, respectively. The observed critical period suggests that in rainfed chickpea, a carefully timed weed removal could prevent grain yield losses.

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.

scholarly journals Effect of nitrogen addition on the comparative productivity of corn and velvetleaf (Abutilon theophrasti)

Weed Science ◽  
2006 ◽  
Vol 54 (02) ◽  
pp. 354-363 ◽  
Author(s):  
Darren C. Barker ◽  
Stevan Z. Knezevic ◽  
Alex R. Martin ◽  
Daniel T. Walters ◽  
John L. Lindquist
Keyword(s):  
Leaf Area ◽  
Field Experiments ◽  
Yield Loss ◽  
Biomass Accumulation ◽  
Nitrogen Addition ◽  
Corn Yield ◽  
N Addition ◽  
Area Index ◽  
Nitrogen Levels ◽  
Weed Growth

Weeds that respond more to nitrogen fertilizer than crops may be more competitive under high nitrogen (N) conditions. Therefore, understanding the effects of nitrogen on crop and weed growth and competition is critical. Field experiments were conducted at two locations in 1999 and 2000 to determine the influence of varying levels of N addition on corn and velvetleaf height, leaf area, biomass accumulation, and yield. Nitrogen addition increased corn and velvetleaf height by a maximum of 15 and 68%, respectively. N addition increased corn and velvetleaf maximum leaf area index (LAI) by up to 51 and 90%. Corn and velvetleaf maximum biomass increased by up to 68 and 89% with N addition. Competition from corn had the greatest effect on velvetleaf growth, reducing its biomass by up to 90% compared with monoculture velvetleaf. Corn response to N addition was less than that of velvetleaf, indicating that velvetleaf may be most competitive at high levels of nitrogen and least competitive when nitrogen levels are low. Corn yield declined with increasing velvetleaf interference at all levels of N addition. However, corn yield loss due to velvetleaf interference was similar across N treatments except in one site–year, where yield loss increased with increasing N addition. Corn yield loss due to velvetleaf interference may increase with increasing N supply when velvetleaf emergence and early season growth are similar to that of corn.

The critical weed-free period in glyphosate-resistant soybean in Ontario is similar to previous estimates using glyphosate-susceptible soybean

2019 ◽  
Vol 99 (4) ◽  
pp. 437-443
Author(s):  
Nader Soltani ◽  
Robert E. Nurse ◽  
Amit J. Jhala ◽  
Peter H. Sikkema
Keyword(s):  
Growth Stage ◽  
Field Experiments ◽  
Yield Loss ◽  
Growth Stages ◽  
Weed Species ◽  
Weed Biomass ◽  
Weed Density ◽  
Weed Interference ◽  
Beginning Of Flowering ◽  
Minimal Reduction

A study consisting of 13 field experiments was conducted during 2014–2016 in southwestern Ontario and southcentral Nebraska (Clay Center) to determine the effect of late-emerging weeds on the yield of glyphosate-resistant soybean. Soybean was maintained weed-free with glyphosate (900 g ae ha−1) up to the VC (cotyledon), V1 (first trifoliate), V2 (second trifoliate), V3 (third trifoliate), V4 (fourth trifoliate), and R1 (beginning of flowering) growth stages, after which weeds were allowed to naturally infest the soybean plots. The total weed density was reduced to 24%, 63%, 67%, 72%, 76%, and 92% in Environment 1 (Exeter, Harrow, and Ridgetown) when soybean was maintained weed-free up to the VC, V1, V2, V3, V4, and R1 soybean growth stages, respectively. The total weed biomass was reduced by 33%, 82%, 95%, 97%, 97%, and 100% in Environment 1 (Exeter, Harrow, and Ridgetown) and 28%, 100%, 100%, 100%, 100%, and 100% in Environment 2 (Clay Center) when soybean was maintained weed-free up to the VC, V1, V2, V3, V4, and R1 stages, respectively. The critical weed-free periods for a 2.5%, 5%, and 10% yield loss in soybean were the V1–V2, VC–V1, and VC–V1 soybean stages in Environment 1 (Exeter, Harrow, and Ridgetown) and V2–V3, V2–V3, and V1–V2 soybean stages in Environment 2 (Clay Center), respectively. For the weed species evaluated, there was a minimal reduction in weed biomass (5% or less) when soybean was maintained weed-free beyond the V3 soybean growth stage. These results shows that soybean must be maintained weed-free up to the V3 growth stage to minimize yield loss due to weed interference.

Interference between hemp sesbania (Sesbania exaltata) and soybean (Glycine max) in response to irrigation and nitrogen

Weed Science ◽  
1997 ◽  
Vol 45 (1) ◽  
pp. 91-97 ◽  
Author(s):  
C. Andy King ◽  
Larry C. Purcell
Keyword(s):  
Field Experiments ◽  
Yield Loss ◽  
Individual Species ◽  
Weed Species ◽  
Soybean Yield ◽  
Sesbania Exaltata ◽  
Competition For Light ◽  
Hemp Sesbania ◽  
Chamber Studies ◽  
Growth Chamber Studies

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.

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