A Model of Competition for Light Between Peanut (Arachis hypogaea) and Broadleaf Weeds

Weed Science ◽  
1995 ◽  
Vol 43 (2) ◽  
pp. 247-257 ◽  
Author(s):  
James C. Barbour ◽  
David C. Bridges
Keyword(s):  
Arachis Hypogaea ◽  
Simulation Models ◽  
Field Studies ◽  
Critical Parameters ◽  
Yield Losses ◽  
Weed Species ◽  
Model Predictions ◽  
Competition For Light ◽  
Different Populations ◽  
Light Capture

A model of competition for light between peanut and three broadleaf weed species has been developed to run with the PNUTGRO model. The model simulates shading of the peanut canopy by reducing the total daily PAR received by the peanuts in a manner that realistically represents timing and quantity of light capture by the weeds. Data were collected in nursery plots of Florida beggarweed, sicklepod, and wild poinsettia in 1989, 1990, and 1991. These data provided the values for the critical parameters: maximum attenuation of PAR by the weed, time when the weed overtops the peanut canopy, time when maximum attenuation is reached, and the distance of influence of the weed. Florida beggarweed overtopped the peanut canopy 52 DAP, and reduced PAR reaching the peanuts 45% by 73 DAP. Sicklepod overtopped the peanut canopy 42 DAP and reached an attenuation of 41% 79 DAP. Wild poinsettia overtopped the peanut canopy 44 DAP, and had an attenuation value of 39% 85 DAP. The distances of influence were 162, 150, and 192 cm for Florida beggarweed, sicklepod, and wild poinsettia, respectively. Observed yield losses in the distance of influence were 26, 27, and 22%, respectively. The model predictions accounted for at least 90% of the yield losses observed in field studies. The model also proved capable of simulating competitive differences between morphologically and phenologically different populations of Florida beggarweed. Simulation models will play an important role in reducing the expenditure of time and resources required to document yield losses due to weeds in peanuts.

Absorption, Translocation, and Phytotoxicity of Chlorimuron and 2,4-Db Mixtures in Peanut (Arachis Hypogaea) and Selected Weed Species

Weed Science ◽  
1993 ◽  
Vol 41 (3) ◽  
pp. 347-352 ◽  
Author(s):  
Glenn R. Wehtje ◽  
John W. Wilcut ◽  
John A. Mcguire
Keyword(s):  
Weed Control ◽  
Arachis Hypogaea ◽  
Field Studies ◽  
The Other ◽  
Weed Species ◽  
Greenhouse Experiments ◽  
Crop Injury ◽  
Treated Leaf ◽  
Better Than

Mixtures of chlorimuron and 2,4-DB were additive with respect to crop injury and were either additive or slightly antagonistic with respect to weed control in greenhouse experiments. Absorption and translocation of14C following application of14C-chlorimuron and14C-2,4-DB were not affected by the presence of the other unlabeled herbicide, except in Florida beggarweed and peanut where 2,4-DB affected distribution of14C-chlorimuron in the treated leaf. In field studies, maximum efficacy was obtained with mixtures of chlorimuron plus 2,4-DB applied 7 or 9 wk after planting. Florida beggarweed control was greatest with chlorimuron or chlorimuron mixtures while the addition of 2,4-DB to chlorimuron improved morningglory and sicklepod control. At 9 and 11 wk after planting, addition of 2,4-DB to chlorimuron controlled Florida beggarweed better than chlorimuron alone. Peanut yields were increased by the addition of 2,4-DB at later applications.

scholarly journals Modelling weed competition and yield losses to study the effect of omission of herbicides in winter wheat.

1990 ◽  
Vol 38 (4) ◽  
pp. 711-718
Author(s):  
L.A.P. Lotz ◽  
M.J. Kropff ◽  
M.W. Groeneveld
Keyword(s):  
Winter Wheat ◽  
Crop Yield ◽  
Sandy Soil ◽  
Morphological Characteristics ◽  
Weed Competition ◽  
Yield Losses ◽  
Emergence Time ◽  
Weed Species ◽  
Competition For Light ◽  
Tuber Crops

Omission of application of various herbicides to winter wheat cv. Arminda, cv. Citadel, cv. Okapi, cv. Granada, cv. Sarino and cv. Tombola on clay and sandy soil in 1982-86 caused a significantly lower crop yield only when the densities of certain weed species were extremely high in spring. A dynamic model simulating the competition for light and water between broadleaved weeds and winter wheat was used to assess the observed small effects of weeds on yield in terms of the relative emergence time, physiological and morphological characteristics of weeds. Like the experiments, the simulations indicated that in the Netherlands weeds emerging in spring hardly affect crop yield. Weeds emerging in autumn, however, reduced crop yield considerably if they grew as tall as winter wheat (20% loss at a density of 100 plants/msuperscript 2). The results are discussed in relation to characteristics of crop rotation systems that include root and tuber crops. (Abstract retrieved from CAB Abstracts by CABI’s permission)

scholarly journals Dicamba emissions under field conditions as affected by surface condition

2020 ◽  
pp. 1-8
Author(s):  
Thomas C. Mueller ◽  
Lawrence E. Steckel
Keyword(s):  
Plant Material ◽  
Surface Condition ◽  
Simulation Models ◽  
Field Studies ◽  
Green Plant ◽  
Field Conditions ◽  
Bare Ground ◽  
Weed Species ◽  
Target Movement ◽  
Green Plants

Abstract The evolution and widespread distribution of glyphosate-resistant broadleaf weed species catalyzed the introduction of dicamba-resistant crops that allow this herbicide to be applied POST to soybean and cotton. Applications of dicamba that are most cited for off-target movement have occurred in June and July in many states when weeds are often in high densities and at least 10 cm or taller at the time of application. For registration purposes, most field studies examining pesticide emissions are conducted using bare ground or very small plants. Research was conducted in Knoxville, TN, in the summer of 2017, 2018, and 2019 to examine the effect of application surface (tilled soil, dead plants, green plants) on dicamba emissions under field conditions. Dicamba emissions after application were affected by the treated surface in all years, with the order from least to most emissions being dead plants < tilled soil < green plant material. In fact, dicamba emissions were >300% when applied to green plants compared to other surfaces. These findings suggest that dicamba applications made to bare ground will likely underestimate what may occur under normal field use conditions when POST applications are made and the crop canopy or weed groundcover is nearly 100% green material. A potential change to enhance the accuracy of current environmental simulation models would be to increase the theoretical findings to allow for the effect of green plant material on dicamba emissions under field conditions.

Antagonism of Paraquat Phytotoxicity in Peanuts (Arachis hypogaea) and Selected Weed Species by Naptalam

Weed Science ◽  
1991 ◽  
Vol 39 (4) ◽  
pp. 634-639 ◽  
Author(s):  
Glenn R. Wehtje ◽  
John W. Wilcut ◽  
Daniel P. Dylewski ◽  
John A. McGuire ◽  
T. Vint Hicks
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Arachis Hypogaea ◽  
Leaf Surface ◽  
Field Studies ◽  
Weed Species ◽  
Absorption Studies ◽  
Scanning Electron

Greenhouse and field studies demonstrated that naptalam reduced paraquat activity by as much as 30% on sicklepod, smallflower morningglory, Florida beggarweed, and peanut Sequential application experiments, i.e. naptalam applied 2 or 24 h prior to an application of paraquat, as well as absorption studies utilizing14C-paraquat, indicated that the antagonism was due largely to reduced paraquat absorption. Scanning electron microscopy revealed that application of naptalam, as well as naptalam applied with paraquat, resulted in amorphous deposits on the leaf surface which may account for the antagonism.

Modeling Soybean Growth and Canopy Apportionment in Weed-Soybean (Glycine max) Competition

Weed Science ◽  
1990 ◽  
Vol 38 (6) ◽  
pp. 522-527 ◽  
Author(s):  
David R. Pike ◽  
Edward W. Stoller ◽  
Loyd M. Wax
Keyword(s):  
Leaf Area ◽  
Field Studies ◽  
Linear Functions ◽  
Growth And Yield ◽  
Yield Losses ◽  
Growth Responses ◽  
Weed Species ◽  
Soybean Yield ◽  
Soybean Plants ◽  
Area Of Influence

Field studies using area-of-influence techniques were conducted in 1987 and 1988 to evaluate soybean growth and yield, and to predict soybean yield losses from photographs of jimsonweed and common cocklebur canopies. Differences in weed competitiveness within the 100-cm area of influence were induced by dates of soybean planting, locations, weed species, and years. Soybean yield losses within the first 20-cm interval from weeds correlated well with yield of all soybean plants within 100 cm of weeds (r2= 0.86). Soybean growth responses as a function of distance from weeds were best described by complex polynomials, but simple linear functions, based on a data point from soybean plants nearest a weed and from the average of plants 60 to 100 cm from a weed, closely approximately actual yield losses (r2= 0.96). Soybean yield losses were highly correlated (r2= 0.84) with leaf area of weeds as viewed from directly above the weed-crop canopy. Weed canopy diameter, measured from overhead photographs 8 weeks after soybean emergence, also correlated well with soybean yield losses (r2= 0.82), but correlation with actual weed leaf area was not significant (r2= 0.31).

Influence of chaff and chaff lines on weed seed survival and seedling emergence in Australian cropping systems

2020 ◽  
pp. 1-22
Author(s):  
Michael J. Walsh ◽  
Annie E. Rayner ◽  
Annie Rutledge ◽  
John C. Broster
Keyword(s):  
Cropping Systems ◽  
Seedling Emergence ◽  
Field Studies ◽  
Wild Oat ◽  
Weed Seed ◽  
Weed Species ◽  
Environment Effect ◽  
Seed Survival ◽  
Cropping Seasons ◽  
Rigid Ryegrass

Abstract Chaff lining and chaff tramlining are harvest weed seed control (HWSC) systems that involve the concentration of weed seed containing chaff material into narrow (20 to 30 cm) rows between or on the harvester wheel tracks during harvest. These lines of chaff are left intact in the fields through subsequent cropping seasons in the assumption that the chaff environment is unfavourable for weed seed survival. The chaff row environment effect on weed seed survival was examined in field studies, while chaff response studies determined the influence of increasing amounts of chaff on weed seedling emergence. The objectives of these studies were to determine 1) the influence of chaff lines on the summer-autumn seed survival of selected weed species; and 2) the influence of chaff type and amount on rigid ryegrass seedling emergence. There was frequently no difference (P>0.05) in survival of seed of four weed species (rigid ryegrass, wild oat, annual sowthistle and turnip weed) when these seed were placed beneath or beside chaff lines. There was one instance where wild oat seed survival was increased (P<0.05) when seed were placed beneath compared to beside a chaff line. The pot studies determined that increasing amounts of chaff consistently resulted in decreasing numbers of rigid ryegrass seedlings emerging through chaff material. The suppression of emergence broadly followed a linear relationship where there was approximately a 2.0% reduction in emergence with every 1.0 t ha-1 increase in chaff material. This relationship was consistent across wheat, barley, canola and lupin chaff types, indicating that the physical presence of the chaff was more important than chaff type. These studies indicated that chaff lines may not affect the over summer-autumn survival of the contained weed seeds but the subsequent emergence of weed seedlings will be restricted by high amounts of chaff (>40 t ha-1).

Yellow Nutsedge (Cyperus esculentus) Control in Peanuts (Arachis hypogaea)

1992 ◽  
Vol 6 (1) ◽  
pp. 108-112 ◽  
Author(s):  
W. James Grichar
Keyword(s):  
Arachis Hypogaea ◽  
Field Studies ◽  
Cyperus Esculentus ◽  
Yellow Nutsedge ◽  
Moisture Conditions ◽  
Competitive Nature

Field studies were conducted from 1986 through 1988 to evaluate various herbicides for yellow nutsedge control and peanut yields. Three applications of pyridate provided control comparable to two applications of bentazon with yellow nutsedge regrowth beginning 3 to 4 wk after application depending on moisture conditions. Crop oil concentrate did not improve the activity of pyridate. Flurtamone provided control comparable with that of metolachlor. Nutsedge control with fomesafen was erratic with peanut injury noted. Peanut yields did not reflect the competitive nature of nutsedge.

Foliar Penetration and Phytotoxicity of Paraquat as Influenced by Peanut Cultivar1

1991 ◽  
Vol 18 (2) ◽  
pp. 67-71 ◽  
Author(s):  
G. Wehtje ◽  
J. W. Wilcut ◽  
J. A. McGuire ◽  
T. V. Hicks
Keyword(s):  
Arachis Hypogaea ◽  
Untreated Control ◽  
Field Studies ◽  
Yield Potential ◽  
Laboratory Studies ◽  
Foliar Absorption ◽  
Arachis Hypogaea L ◽  
Herbicide Treatments ◽  
Peanut Cultivars

Abstract Field studies were conducted over a three year period to examine the sensitivity of four peanut (Arachis hypogaea L.) cultivars (Florunner, Sunrunner, Southern runner, and NC 7) to foliar applications of paraquat (1, 1′-dimethyl-4, 4′-bipyridinium ion). Treatments included an untreated control and four herbicide treatments: paraquat applied alone at 0.14 and 0.28 kg/ha, or tank mixed with alachlor [2-chloro-N-(2, 6-diethylphenyl)-N-(methoxymethyl)acetamide] at 4.40 kg/ha. Weeds were hand-removed so that only herbicidal treatments were variables. Paraquat phytotoxicity did not differ between cultivars. No cultivar evaluated was abnormally sensitive nor tolerant to any paraquat-containing treatment. Laboratory studies utilizing radio labelled paraquat revealed that foliar absorption and translocation of paraquat did not vary between peanut cultivars. Yield differences were attributed to differences in yield potential between cultivars.

Laboratory and field studies on metribuzin persistence in soil and its prediction by simulation models

1997 ◽  
Vol 63 (1-4) ◽  
pp. 47-61 ◽  
Author(s):  
Y. Lechón ◽  
A. I. García‐Valcárcel ◽  
T. Matienzo ◽  
C. Sánchez‐Brunete ◽  
J. L. Tadeo
Keyword(s):  
Simulation Models ◽  
Field Studies

scholarly journals Interactions of Nitrogen Source and Rate and Weed Removal Timing Relative to Nitrogen Content in Corn and Weeds and Corn Grain Yield

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Alexandra M. Knight ◽  
Wesley J. Everman ◽  
David L. Jordan ◽  
Ronnie W. Heiniger ◽  
T. Jot Smyth
Keyword(s):  
Grain Yield ◽  
Weed Management ◽  
Management Strategies ◽  
Field Studies ◽  
Weed Species ◽  
Weed Interference ◽  
Coated Urea ◽  
N Fertility ◽  
Corn Grain ◽  
Corn Grain Yield

Adequate fertility combined with effective weed management is important in maximizing corn (Zea mays L.) grain yield. Corn uptake of nitrogen (N) is dependent upon many factors including weed species and density and the rate and formulation of applied N fertilizer. Understanding interactions among corn, applied N, and weeds is important in developing management strategies. Field studies were conducted in North Carolina to compare corn and weed responses to urea ammonium nitrate (UAN), sulfur-coated urea (SCU), and composted poultry litter (CPL) when a mixture of Palmer amaranth (Amaranthus palmeri S. Wats.) and large crabgrass (Digitaria sanguinalis L.) was removed with herbicides at heights of 8 or 16 cm. These respective removal timings corresponded with 22 and 28 days after corn planting or V2 and V3 stages of growth, respectively. Differences in N content in above-ground biomass of corn were noted early in the season due to weed interference but did not translate into differences in corn grain yield. Interactions of N source and N rate were noted for corn grain yield but these factors did not interact with timing of weed control. These results underscore that timely implementation of control tactics regardless of N fertility management is important to protect corn grain yield.

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