scholarly journals EFFECTS OF DURATION OF HEMP-NETTLE (Galeopsis tetrahit) INTERFERENCE IN OATS (Avena sativa) AND ALFALFA (Medicago sativa)

1990 ◽  
Vol 70 (3) ◽  
pp. 809-816
Author(s):  
ANNE LÉGÈRE ◽  
JEAN-MARC DESCHÊNES
Keyword(s):  
Medicago Sativa ◽  
Avena Sativa ◽  
Field Experiments ◽  
Early Spring ◽  
Residual Effects ◽  
Yield Reduction ◽  
Quebec City ◽  
Negative Effects ◽  
Weed Interference ◽  
Spring Planting

Effects of duration of common hemp-nettle (Galeopsis tetrahit L.) interference on oat (Avena sativa L.) yields, and alfalfa (Medicago sativa L.) yields during the year of establishment were measured in field experiments conducted in the Québec City area. Hemp-nettle growth was reduced in oats compared to that in alfalfa. Effects of duration of hemp-nettle interference on oat yields were significant in one out of two years. A 35% yield reduction was measured in oats after 12 wk of interference following an early spring planting (late April). First-cut alfalfa yields decreased as duration of hemp-nettle interference increased. Residual effects of hemp-nettle interference were also measured on second-cut alfalfa yields even though hemp-nettle had been absent from alfalfa stands throughout the regrowth period. Although early spring planting is generally recommended for alfalfa in the eastern Québec region, this practice appeared unsuitable for sites heavily infested with hemp-nettle, considering the early germination of the weed and its negative effects on crop yield.Key words: Hemp-nettle, Galeopsis tetrahit, weed competition, weed interference

Interference of Annual Weeds in Seedling Alfalfa (Medicago sativa)

Weed Science ◽  
1988 ◽  
Vol 36 (5) ◽  
pp. 583-588 ◽  
Author(s):  
Albert J. Fischer ◽  
Jean H. Dawson ◽  
Arnold P. Appleby
Keyword(s):  
Medicago Sativa ◽  
Bromus Tectorum ◽  
Early Spring ◽  
Amaranthus Retroflexus ◽  
Downy Brome ◽  
Weed Interference ◽  
Alfalfa Hay ◽  
Winter Annual ◽  
Annual Weeds

Barnyardgrass [Echinochloa crus-galli(L.) Beauv. #4ECHCG] and pigweeds (mixture ofAmaranthus retroflexusL. # AMARE andA. powelliiS. Wats. # AMAPO) seeded separately with alfalfa (Medicago sativaL.) in mid-August suppressed alfalfa severely before frost killed them in October and November. Some alfalfa was killed, and yield of alfalfa forage was reduced in each of three harvests the following year. These weeds did not harm alfalfa seeded in mid-September. Downy brome (Bromus tectorumL. # BROTE) and tumble mustard (Sisymbrium altissimumL. # SSYAL) suppressed alfalfa seeded in August and September. They reduced alfalfa stands and reduced yield of alfalfa forage in each of three harvests the following year. Alfalfa seeded August 27 and allowed to compete with a mixture of these species for various periods was injured most by weeds that emerged with the alfalfa and remained uncontrolled until forage harvest in May. These weeds did not reduce alfalfa yields if removed by 36 days after alfalfa emergence. Thereafter, yield decreased as the period of weed interference increased. Interference was most damaging in early spring, when growth of winter annual weeds was rapid and vigorous. Weeds seeded 65 or more days after alfalfa emergence did not reduce alfalfa yields but sometimes produced enough biomass to reduce the quality of the first-cutting alfalfa hay.

Time of Removal of Crownbeard (Verbesina encelioides) on Peanut Yield

2005 ◽  
Vol 19 (2) ◽  
pp. 380-384 ◽  
Author(s):  
Rodney L. Farris ◽  
Cody J. Gray ◽  
Don S. Murray ◽  
Laval M. Verhalen
Keyword(s):  
Natural Population ◽  
Field Experiments ◽  
Yield Reduction ◽  
Weed Density ◽  
Weed Interference ◽  
Weed Growth ◽  
Poor Predictor ◽  
Verbesina Encelioides ◽  
Shell Peanut ◽  
Weed Removal

Field experiments were conducted in southwestern Oklahoma near Colony in 2000 and near Ft. Cobb in 2001 to quantify the effect of time of removal of a natural population of crownbeard on peanut yield. Weed densities and dry weed weights were measured at eight weed-removal times, and in-shell peanut yields were determined at harvest. Crownbeard was removed at 0 (the weed-free check), 4, 6, 8, 10, 12, 14, and 16 wk (full season) after crop emergence (WAE). Weed density was a poor predictor for dry weed weight and peanut yield; however, dry weed weight and time of removal were good predictors for peanut yield. Weed growth was minimal up to 4 WAE and increased linearly after that time. For each week of weed growth, a 0.52 kg/plot increase in dry weed weight was measured. Peanut yield decreased linearly because of crownbeard competition. For each kilogram per plot increase in dry weed weight, a 129 kg/ha or 5.1% peanut yield reduction took place. For each week of weed interference, a 75 kg/ha or 2.8% peanut yield reduction occurred. Crownbeard removal by or before 4 WAE will minimize losses in peanut yield because of interference.

Tolerance of Direct-Seeded Green Onions to Herbicides Applied Before or After Crop Emergence

2007 ◽  
Vol 21 (1) ◽  
pp. 119-123 ◽  
Author(s):  
Jason K. Norsworthy ◽  
John P. Smith ◽  
Charles Meister
Keyword(s):  
Field Experiments ◽  
Negative Effects ◽  
Weed Interference ◽  
Direct Seeded ◽  
Preemergence Herbicides

Field experiments were conducted in 2004 and 2005 to determine the tolerance of direct-seeded green onion to selected herbicides applied before or after green onion emergence. Preemergence herbicides included S-metolachlor, pendimethalin, dimethenamid, quinclorac, pronamide, ethofumesate, and DCPA, a registered standard. Herbicide applied to two- to three-leaf green onion included glyphosate, trifloxysulfuron, flumioxazin, phenmedipham, ethalfluralin, pendimethalin, S-metolachlor, and oxyfluorfen. Plots were cultivated and hand weeded to minimize negative effects of weed interference on the crop. All herbicides applied at seeding, excluding DCPA, caused excessive injury (>25%) to green onion in at least 1 of 2 years. Oxyfluorfen, ethalfluralin, or S-metolachlor applied after crop emergence caused less than 10% injury in both years to green onion. Green onion yields following treatment with oxyfluorfen, ethalfluralin, or S-metolachlor were equivalent to the nontreated control. All other herbicides applied after crop emergence resulted in height, density, or yield reductions relative to a nontreated control in at least 1 of 2 years.

Soybean response to weed interference and defoliation

Weed Science ◽  
1999 ◽  
Vol 47 (1) ◽  
pp. 90-94 ◽  
Author(s):  
Charles F. Grymes ◽  
James L. Griffin ◽  
David J. Boethel ◽  
B. Rogers Leonard ◽  
David L. Jordan ◽  
...  
Keyword(s):  
Seed Development ◽  
Field Experiments ◽  
Dry Weight ◽  
Yield Reduction ◽  
Growth Stages ◽  
Lower Yield ◽  
Full Bloom ◽  
Soybean Yield ◽  
Weed Interference ◽  
Hemp Sesbania

Field experiments were conducted in Louisiana over 2 yr to evaluate the influence of full-season interference from johnsongrass, common cocklebur, or hemp sesbania at densities of 2.5, 0.5, and 2.0 plants m–1of row, respectively, and simulated insect defoliation of soybean on weed and soybean growth. Defoliation at R2 (full bloom) and R5 (beginning seed development) soybean growth stages was accomplished by removal of zero, one, or two leaflets per soybean trifoliate, which approximated 0, 33, and 66% defoliation, respectively. Height and dry weight of all weeds were not affected by soybean defoliation level or defoliation stage. Soybean height 3 wk after defoliation at R5 was not influenced by weed interference, soybean defoliation level, or defoliation stage in either year. Averaged across soybean defoliation levels and stages in 1994, johnsongrass, common cocklebur, and hemp sesbania reduced soybean yields 30, 15, and 14%, respectively. In 1995, johnsongrass reduced soybean yield 35%. As soybean defoliation level increased, a linear decrease in soybean yield was observed. Averaged across weeds and soybean defoliation stages, 33 and 66% defoliation reduced soybean yield 6 and 20% in 1994 and 12 and 33% in 1995, respectively. Defoliation at R5 resulted in 10% lower yield than defoliation at R2 in one of two years. Yield reduction due to combinations of weeds and soybean defoliation was additive.

Chlorsulfuron and Metsulfuron Residues on Double-Cropped Soybeans (Glycine max)

1988 ◽  
Vol 2 (1) ◽  
pp. 49-52 ◽  
Author(s):  
Ronald L. Ritter ◽  
Thomas C. Harris ◽  
Lisa M. Kaufman
Keyword(s):  
Triticum Aestivum ◽  
Glycine Max ◽  
Field Experiments ◽  
Soybean Seed ◽  
Field Studies ◽  
Early Spring ◽  
Residual Effects ◽  
Early Winter ◽  
No Till ◽  
Seed Yields

In field experiments in 1981, 36 g ai/ha of chlorsulfuron {2-chloro-N-[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)amino] carbonyl] benzenesulfonamide} applied to winter wheat (Triticum aestivumL. ‘Arthur’) in early spring reduced seed yield in conventional and no-till plantings of double-cropped soybeans [Glycine max(L.) ‘Essex’]. From 1982 to 1984, three rates of chlorsulfuron (9, 18, and 36 g/ha) were applied at three different times (preemergence, early winter, and early spring) to study their residual effects on double-cropped soybeans. Chlorsulfuron at 36 g/ha applied preemergence or early spring reduced soybean seed yields when averaged over the 3-yr period. Metsulfuron {2-[[[[(4-methoxy-6-methyl-1,3,5-triazine-2-yl)amino] carbonyl] amino] sulfonyl] benzoic acid} was tested at three rates (4.5, 9, and 18 g/ha) applied at three times (same as chlorsulfuron) in field studies in 1983 and 1984. Metsulfuron did not injure subsequently planted no-till soybeans.

Improving the performance of canola in retained wheat stubble

2006 ◽  
Vol 57 (11) ◽  
pp. 1203 ◽  
Author(s):  
S. E. Bruce ◽  
M. H. Ryan ◽  
J. A. Kirkegaard ◽  
J. Pratley
Keyword(s):  
Shoot Growth ◽  
Field Experiments ◽  
Seedling Emergence ◽  
Growth And Yield ◽  
Yield Reduction ◽  
Negative Effects ◽  
Stubble Retention ◽  
Initial Reduction ◽  
Wheat Stubble ◽  
Early Effects

Four field experiments investigated strategies to reduce the negative effects of surface-retained wheat stubble on the emergence, growth, and yield of canola. All experiments compared 3 stubble treatments: (1) no stubble (stubble removed or burnt); (2) stubble-spread (6 t/ha wheat stubble evenly distributed on the surface); and (3) stubble-inter-row (6 t/ha stubble distributed on the inter-rows only). Seedling emergence was reduced in the presence of evenly spread stubble compared with no stubble, and the emerged seedlings had longer hypocotyls, reduced leaf number, and reduced biomass. Reduced shoot growth was not associated with lower shoot N concentration. These early effects on shoot growth persisted at 3 of the 4 sites, resulting in average yield reductions of 26% (range 0–59%) in the stubble-spread treatments compared with no stubble. Restricting stubble to the inter-rows resulted in an initial reduction in seedling growth compared with no stubble, but this difference had diminished by flowering. The yield for the stubble inter-row treatment was similar to no stubble at 2 sites and intermediate between no stubble and stubble-spread at the other 2 sites, with an overall yield reduction of 5.3% compared with no stubble. The results indicate that the negative effects on canola performance of surface-retained wheat stubble can be largely eliminated by adopting sowing techniques that push wheat stubble away from the seeding row and onto the inter-row. This provides a viable option to stubble burning and maintains the benefits of stubble retention.

The Critical Period of Weed Control in Lentil (Lens culinaris) in the Pacific Northwest

Weed Science ◽  
2012 ◽  
Vol 60 (1) ◽  
pp. 81-85 ◽  
Author(s):  
Jamin A. Smitchger ◽  
Ian C. Burke ◽  
Joseph P. Yenish
Keyword(s):  
Weed Control ◽  
Pacific Northwest ◽  
Seed Yield ◽  
Critical Period ◽  
Field Experiments ◽  
Yield Reduction ◽  
Weed Interference ◽  
The Pacific ◽  
Crop Growth Stage ◽  
Crop Maturity

The critical period of weed control (CPWC) for ‘Pardina’ and ‘Brewer’ lentil was determined in field experiments near Pullman, WA, in 2008 and 2009. Trial treatments were kept either weed free for periods of 0, 14, 25, 35, 45, 60, 75, or ∼90 d after emergence (DAE), or weeds were allowed to grow before removal for periods of 0, 14, 25, 35, 45, 60, 75, or ∼90 DAE. Averaged across varieties, lentil with season-long weed interference had 29.5 and 32% seed yield reduction compared to weed-free lentils in 2008 and 2009, respectively. When measured at crop maturity, a 1% loss in lentil seed yield resulted from each 5.68 g m−2of dry weed biomass. Based on a 5% yield loss threshold, the CPWC for lentil was estimated to be from 270 to 999 growing degree days (GDD), 22 to 57 DAE, or crop growth stage (CGS) 7 to the early pod stage during 2008. In 2009, the CPWC was 624 to 650 GDD, with no occurrence of a CPWC when estimated using DAE and CGS. Spiny sowthistle emerged and competed with the lentil crop later in the growing season than mayweed chamomile, indicating that mayweed chamomile may be an earlier and stronger competitor than spiny sowthistle.

Estimación de biomasa aérea de forrajes de invierno bajo riego a través de un dron

2019 ◽  
Vol 12 (4) ◽  
Author(s):  
Francisco Gavi Reyes ◽  
César Botello-Aguillón ◽  
Leonardo Tijerina-Chávez ◽  
Arturo Galvis-Spíndola ◽  
Rodrigo Roblero-Hidalgo
Keyword(s):  
Medicago Sativa ◽  
Avena Sativa ◽  
Medicago Sativa L

E Objetivo: Desarrollar un procedimiento para estimar biomasa con imágenes digitales captadas desde un dron y modelación 3D (ID-Dron-3D) aplicable en alfalfa (Medicago sativa L.) y avena forrajera (Avena sativa L.). Diseño/metodología/aproximación: Con una cámara digital acoplada al dron se obtuvieron imágenes antes de la cosecha de los cultivos, que fueron procesadas con software para luego estimar volumen de biomasa. En cada cultivo se midió altura de la planta y área cosechada, volumen aparente y real de biomasa, y peso de biomasa fresca y seca. Resultados: Con base en el análisis de regresión se obtuvieron modelos lineales a una p<0.05 para predecir: biomasa fresca en avena (R2=0.70) y alfalfa (R2 =0.47); y biomasa seca en avena (R2=0.78) y en alfalfa (R2=0.31) mediante ID-Dron-3D. Limitaciones del estudio/implicaciones: Considerando las R2 de los modelos obtenidos, los resultados en la avena forrajera fueron mejores, respecto a los detectados en alfalfa, lo cual se puede deber a la mayor variabilidad de la cobertura vegetal, ya que, en algunas unidades de muestreo, las plantas de alfalfa no cubrían completamente el suelo. Hallazgos/conclusiones: El rendimiento de biomasa fresca y seca de ambos cultivos se correlacionó significativamente con su respectivo volumen aparente estimado con imágenes digitales tomadas desde un dron y su procesamiento 3D (ID-Dron-3D).

Flat-cutting loosening in the system of fallow cultivation of chernozem soil and weediness of crops

2017 ◽  
Vol 1 (92) ◽  
pp. 78-84
Author(s):  
G. Koval ◽  
M. Kaliyevskiy ◽  
V. Yeshchenko ◽  
I. Martyniuk ◽  
N. Martyniuk
Keyword(s):  
Species Composition ◽  
Crop Rotation ◽  
Field Experiments ◽  
Early Spring ◽  
Weed Species ◽  
Wild Mustard ◽  
Spring Crop ◽  
White Campion ◽  
Investigation Methods ◽  
Top Soil

The article presents the results of field experiments, where on the basis of podsolized heavy loamy chernozem the influence of replacement of mouldboard ploughing with nonmouldboard cultivation over top soil weediness, weediness at the beginning and end of spring crop vegetation and weed species composition before harve sting were studied. Investigation methods of main fall ploughing under spring crops of five-course rotation: soybeans–rape–wheat–flax–barley at the depths of 15-17, 20-22, 25-27 cm were conducted after post-harvest field tillage. Analysis of data on contamination of the top soil with weed seeds have shown that with the replacement of fall main mouldboard ploughing gwith nonmouldboard cultivation the figure before sowing of all crops withdifferent tillage depthat crop rotation average increased by 131-132%. It caused the increase of actual weed infestation of all crops and at the beginning and end of spring crop vegetationafter different depths of fall nonmouldboard cultivation compared with ploughing at crop rotation average it was 120–132 and 123-138%respectively. Species composition of weeds afterthe replacement of main fall mouldboard ploughing with nonmouldboard cultivation remained mainlyunchanged; although in rape plantings the proportion of white campion and early spring weed sincreased, in wheat plantings– wild mustard andscentless mayweed, insoybean plantings– late spring weeds, in flax plantings– white campion, and in barley plantings– scarlet pimpernel.

Bio-efficacy of post emergence herbicides in boro rice nursery as well as main field and their residual effects on non-target microorganisms

2020 ◽  
Vol 57 (3) ◽  
pp. 199-210
Author(s):  
Rajib Kundu ◽  
Mousumi Mondal ◽  
Sourav Garai ◽  
Ramyajit Mondal ◽  
Ratneswar Poddar
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Field Experiments ◽  
Block Design ◽  
Resistance Index ◽  
Residual Effects ◽  
Cost Ratio ◽  
Main Field ◽  
Weed Species ◽  
Similar Treatment

Field experiments were conducted at research farm of Bidhan Chandra Krishi Viswavidyalaya, Kalyani, West Bengal, India (22°97' N latitude and 88°44' E longitude, 9.75 m above mean sea level) under natural weed infestations in boro season rice (nursery bed as well as main field) during 2017-18 and 2018-19 to evaluate the herbicidal effects on weed floras, yield, non-target soil organisms to optimize the herbicide use for sustainable rice-production. Seven weed control treatments including three doses of bispyribac-sodium 10% SC (150,200, and 250 ml ha-1), two doses of fenoxaprop-p-ethyl 9.3% EC (500 and 625 ml ha-1), one weed free and weedy check were laid out in a randomized complete block design, replicated thrice. Among the tested herbicides, bispyribac-sodium with its highest dose (250 ml ha-1) resulted in maximum weed control efficiency, treatment efficiency index and crop resistance index irrespective of weed species and dates of observation in both nursery as well as main field. Similar treatment also revealed maximum grain yield (5.20 t ha-1), which was 38.38% higher than control, closely followed by Fenoxaprop-p-ethyl (625 ml ha-1) had high efficacy against grasses, sedge and broadleaf weed flora. Maximum net return (Rs. 48765 ha-1) and benefit cost ratio (1.72) were obtained from the treatment which received bispyribac-sodium @ 250 ml ha-1. Based on overall performance, the bispyribac-sodium (250 ml ha-1) may be considered as the best herbicide treatment for weed management in transplanted rice as well as nursery bed.

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