Weed Control in Soybean (Glycine max) with Green Manure Crops

Greenhouse and field experiments were initiated to evaluate rapeseed and mustard species as green manure crops for weed suppression. Under greenhouse conditions incorporating 20 g fresh wt leaf and stem tissue of rapeseed, two white mustards, and brown mustard into 450 g Sharpsburg, silty clay loam soil resulted in significant reductions in weed emergence, biomass, and height. Kochia, shepherd's-purse, and green foxtail emergences were reduced by all green manure crops. Redroot pigweed emergence was reduced by all green manure crops except brown mustard, and velvetleaf emergence was reduced by white mustards only. Kochia and shepherd's-purse fresh weights were reduced by all green manure crops, while redroot pigweed and velvetleaf fresh weights were reduced by brown mustard and white mustard var. Salvo. Green foxtail fresh weight was reduced by all green manure crops except rapeseed. With the exception of shepherd's-purse, no relationship between glucosinolate content of the incorporated green manure and suppression of weed growth was found. Under field conditions, early spring-planted green manure crops reduced early season weed biomass in soybean at one of the two locations. Mustard species as green manure crops reduced total weed biomass in soybean by 40% 4 weeks after emergence (WAE) and 49% 6 WAE. Soybean biomass and yield were sometimes reduced by the incorporation of green manure crops in treatments containing weeds; however, hand-weeded plots with green manure treatments yielded similar to hand-weeded plots without green manure.

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Weed suppression withBrassicagreen manure crops in green pea

Weed Science ◽

10.1017/s0043174500093139 ◽

1997 ◽

Vol 45 (3) ◽

pp. 439-445 ◽

Cited By ~ 76

Author(s):

Kassim Al-Khatib ◽

Carl Libbey ◽

Rick Boydston

Keyword(s):

Green Manure ◽

Weed Suppression ◽

White Mustard ◽

Weed Population ◽

Weed Density ◽

Mount Vernon ◽

Green Foxtail ◽

Green Pea ◽

Dry Soil ◽

Green Manure Crops

Weed suppression in green pea was evaluated when green pea was planted after a fall planting of rapeseed, white mustard, rye, or wheat had been incorporated into the soil in spring. Tests were conducted at Mount Vernon, WA, in 1994 and 1995. Weed suppression in peas varied between different green manure crops. One month after planting, the highest weed population was in green pea following wheat, whereas the lowest was in green pea following rapeseed. Rye and white mustard suppressed early weeds relative to wheat by 25 and 30%, respectively. However, at harvest, weed density was similar in green pea planted after all green manure crops. Weed suppression improved when cultivation or metribuzin at 0.14 kg ha−1was used in combination with white mustard, rapeseed, or rye. Pea population was not affected by green manure crops, except for rapeseed, which reduced pea population. In greenhouse experiments, white mustard added to the soil at 20 g per 400 g air dry soil reduced emergence of shepherd's-purse, kochia, and green foxtail by 97, 54, and 49%, respectively. Rapeseed suppressed emergence of shepherd's-purse, kochia, and green foxtail by 76, 25, and 25%, respectively.

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Weed seed bank emergence across the Corn Belt

Weed Science ◽

10.1017/s0043174500092493 ◽

1997 ◽

Vol 45 (1) ◽

pp. 67-76 ◽

Cited By ~ 72

Author(s):

Frank Forcella ◽

Robert G. Wilson ◽

Jack Dekker ◽

Robert J. Kremer ◽

John Cardina ◽

...

Keyword(s):

Soil Temperature ◽

Field Experiments ◽

Soil Depth ◽

Early Spring ◽

Temperature And Precipitation ◽

Secondary Dormancy ◽

Giant Foxtail ◽

Green Foxtail ◽

Viable Seeds ◽

Common Purslane

Field experiments, conducted from 1991 to 1994, generated information on weed seedbank emergence for 22 site-years from Ohio to Colorado and Minnesota to Missouri. Early spring seedbank densities were estimated through direct extraction of viable seeds from soil cores. Emerged seedlings were recorded periodically, as were daily values for air and soil temperature, and precipitation. Percentages of weed seedbanks that emerged as seedlings were calculated from seedbank and seedling data for each species, and relationships between seedbank emergence and microclimatic variables were sought. Fifteen species were found in 3 or more site-years. Average emergence percentages (and coefficients of variation) of these species were as follows: giant foxtail, 31.2 (84%); velvetleaf, 28.2 (66); kochia, 25.7 (79); Pennsylvania smartweed, 25.1 (65); common purslane, 15.4 (135); common ragweed, 15.0 (110); green foxtail, 8.5 (72); wild proso millet, 6.6 (104); hairy nightshade, 5.2 (62); common sunflower, 5.0 (26); yellow foxtail, 3.4 (67); pigweed species, 3.3 (103); common lambsquarters, 2.7 (111); wild buckwheat, 2.5 (63), and prostrate knotweed, 0.6 (79). Variation among site-years, for some species, could be attributed to microclimate variables thought to induce secondary dormancy in spring. For example, total seasonal emergence percentage of giant foxtail was related positively to the 1st date at which average daily soil temperature at 5 to 10 cm soil depth reached 16 C. Thus, if soil warmed before mid April, secondary dormancy was induced and few seedlings emerged, whereas many seedlings emerged if soil remained cool until June.

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Effect of green manure crops, termination method, stubble crops, and fallow on soil water, available N, and exchangeable P

Canadian Journal of Plant Science ◽

10.1139/cjps-2015-0336 ◽

2016 ◽

Vol 96 (5) ◽

pp. 867-886 ◽

Cited By ~ 3

Author(s):

S.P. Mooleki ◽

Y. Gan ◽

R.L. Lemke ◽

R.P. Zentner ◽

C. Hamel

Keyword(s):

Great Plains ◽

Green Manure ◽

Field Experiments ◽

Northern Great Plains ◽

Available N ◽

Sustainable Agricultural Systems ◽

Lathyrus Sativus L ◽

Nitrogen Phosphorus ◽

Green Manure Crops ◽

Exchangeable P

Green manure crops may have a role to play in the development of sustainable agricultural systems in the semiarid northern Great Plains of North America. This study determined the benefits of different green manure crops, seeding dates, and termination methods on soil nitrogen, phosphorus, and moisture, as well as the performance of durum wheat following green manures the following year. Field experiments were conducted at Swift Current, Saskatchewan, from 2006 to 2009. Three green manure crops [forage pea (Pisum sativum L.), chickling vetch (Lathyrus sativus L.), and black lentil (Lens culinaris Medik.)] were seeded in May, June, and July, and terminated at full bloom using glyphosate, rototilling or by frost. Other treatments included summerfallow and stubble of selected crops harvested for grain or silage. Different green manure crops, seeding dates or termination methods had similar effects on soil moisture, available N, and exchangeable P at termination or the following spring. These effects of green manure management on soil residual characteristics were comparable to those observed under summerfallow, but higher than those on grain or silage stubble. Therefore, green manure is a viable alternative to summerfallowing and could be seeded any time during the growing season. If seeded late, green manure could be terminated by frost, thus saving on costs.

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Growth Stage-Influenced Differential Response of Foxtail and Pigweed Species to Broadcast Flaming

Weed Technology ◽

10.1614/wt-d-10-00005.1 ◽

2010 ◽

Vol 24 (3) ◽

pp. 319-325 ◽

Cited By ~ 29

Author(s):

Santiago M. Ulloa ◽

Avishek Datta ◽

Stevan Z. Knezevic

Keyword(s):

Weed Control ◽

Dry Matter ◽

Growth Stage ◽

Field Experiments ◽

Growth Stages ◽

Weed Species ◽

Common Waterhemp ◽

Species Response ◽

Redroot Pigweed ◽

Green Foxtail

Propane flaming could be an effective alternative tool for weed control in organic cropping systems. However, response of major weeds to broadcast flaming must be determined to optimize its proper use. Therefore, field experiments were conducted at the Haskell Agricultural Laboratory, Concord, NE in 2007 and 2008 using six propane doses and four weed species, including green foxtail, yellow foxtail, redroot pigweed, and common waterhemp. Our objective was to describe dose–response curves for weed control with propane. Propane flaming response was evaluated at three different growth stages for each weed species. The propane doses were 0, 12, 31, 50, 68, and 87 kg ha−1. Flaming treatments were applied utilizing a custom-built flamer mounted on a four-wheeler (all-terrain vehicle) moving at a constant speed of 6.4 km h−1. The response of the weed species to propane flaming was evaluated in terms of visual ratings of weed control and dry matter recorded at 14 d after treatment. Weed species response to propane doses were described by log-logistic models relating propane dose to visual ratings or plant dry matter. Overall, response of the weed species to propane flaming varied among species, growth stages, and propane dose. In general, foxtail species were more tolerant than pigweed species. For example, about 85 and 86 kg ha−1were the calculated doses needed for 90% dry matter reduction in five-leaf green foxtail and four-leaf yellow foxtail compared with significantly lower doses of 68 and 46 kg ha−1of propane for five-leaf redroot pigweed and common waterhemp, respectively. About 90% dry matter reduction in pigweed species was achieved with propane dose ranging from 40 to 80 kg ha−1, depending on the growth stage when flaming was conducted. A similar dose of 40 to 60 kg ha−1provided 80% reduction in dry matter for both foxtail species when flaming was done at their vegetative growth stage. However, none of the doses we tested could provide 90% dry matter reduction in foxtail species at flowering stage. It is important to note that foxtail species started regrowing 2 to 3 wk after flaming. Broadcast flaming has potential for control or suppression of weeds in organic farming.

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Integrated Weed Management Using Planting Pattern, Cultivar, and Herbicide in Dry-Seeded Rice in Northwest India

Weed Science ◽

10.1614/ws-d-13-00115.1 ◽

2014 ◽

Vol 62 (2) ◽

pp. 350-359 ◽

Cited By ~ 11

Author(s):

Gulshan Mahajan ◽

Vikas Poonia ◽

Bhagirath S. Chauhan

Keyword(s):

Grain Yield ◽

Weed Control ◽

Weed Management ◽

Field Experiments ◽

Weed Suppression ◽

Integrated Weed Management ◽

Rice Grain ◽

Planting Pattern ◽

Weed Biomass ◽

Northwest India

Field experiments were conducted in Punjab, India, in 2011 and 2012 to study the integrated effect of planting pattern [uniform rows (20-cm spacing) and paired rows (15-, 25-, and 15-cm spacing)], cultivars (PR-115 and IET-21214), and weed control treatments (nontreated control, pendimethalin 750 g ai ha−1, bispyribac-sodium 25 g ai ha−1, and pendimethalin 750 g ha−1 followed by bispyribac-sodium 25 g ha−1) on weed suppression and rice grain yield in dry-seeded rice. In the nontreated control, IET-21214 had higher grain yield than PR-115 in both planting patterns. However, such differences were not observed within the herbicide treatment. IET-21214 in paired rows, even in nontreated control, provided grain yield (4.7 t ha−1) similar to that in uniform rows coupled with the sole application of pendimethalin (4.3 t ha−1) and bispyribac-sodium (5.0 t ha−1). In uniform rows, sequential application of pendimethalin (PRE) and bispyribac-sodium (POST) provided the highest grain yield among all the weed control treatments and this treatment produced grain yield of 5.9 and 6.1 t ha−1 for PR-115 and IET-21214, respectively. Similarly, in paired rows, PR-115 in paired rows treated with sequential application of pendimethalin and bispyribac-sodium had highest grain yield (6.1 t ha−1) among all the weed control treatments. However, IET-21214 with the sole application of bispyribac-sodium produced grain yield similar to the sequential application of pendimethalin and bispyribac-sodium. At 30 days after sowing, PR-115 in paired rows coupled with pendimethalin application accrued weed biomass (10.7 g m−2) similar to the sequential application of pendimethalin and bispyribac-sodium coupled with uniform rows (8.1 g m−2). Similarly, IET-21214 with bispyribac-sodium application provided weed control similar to the sequential application of pendimethalin and bispyribac-sodium. Our study implied that grain yield of some cultivars could be improved by exploring their competitiveness through paired-row planting patterns with less use of herbicides.

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Efficiency of an Optically Controlled Sprayer for Controlling Weeds in Fallow

Weed Technology ◽

10.1017/s0890037x00044493 ◽

1998 ◽

Vol 12 (4) ◽

pp. 638-645 ◽

Cited By ~ 2

Author(s):

Gail A. Wicks ◽

Warwick L. Felton ◽

Robert D. Murison ◽

Gordon E. Hanson ◽

Paul G. Nash

Keyword(s):

Winter Wheat ◽

Growth Pattern ◽

Field Experiments ◽

Growth Patterns ◽

The Other ◽

Field Of View ◽

Controlled System ◽

Weed Density ◽

Redroot Pigweed ◽

Green Foxtail

Field experiments were conducted to compare performance of glyphosate with three different boom arrangements in a winter wheat-fallow rotation near North Platte, NE, in 1994 and 1995. One boom was optically controlled, and the other boom was for broadcast herbicide applications. Spraying with both booms at the same time was called “dual boom.” The sprayers were tested during May, June, and July on two weed density levels established by applying glyphosate at 0.42 kg ae/ha with and without atrazine at 0.84 kg ai/ha in October following wheat harvest. The dual-boom and the broadcast herbicide applications were more efficient in controlling weeds than the optically controlled system. The dual boom reduced weed density 4.5-fold compared with the optically controlled sprayer used alone. Horseweed < 8 cm tall was more difficult to control with the optically controlled sprayer than redroot pigweed and kochia because of its cylindrical-shaped growth patterns. Barnyardgrass and green foxtail seedlings with an erect growth pattern were also difficult for the sensors to detect. Poorer control with the optically controlled sprayer was associated with failure to identify small weeds, chlorotic plants, inconsistency among sensors, and too wide a field of view (FOV), as sensors were spaced farther apart than presently recommended. The number of sensors on a boom needs to be increased to improve the performance of the optically controlled sprayer.

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Weeds are not always evil: crop-weed relationships are context-dependent and cannot fully explain the positive effects of intercropping on yield

10.1101/2020.04.02.021402 ◽

2020 ◽

Cited By ~ 1

Author(s):

Laura Stefan ◽

Nadine Engbersen ◽

Christian Schoeb

Keyword(s):

Species Richness ◽

Crop Yield ◽

Field Experiments ◽

Weed Suppression ◽

Crop Diversity ◽

Crop Species ◽

Weed Biomass ◽

Positive Effects ◽

Weed Communities ◽

Species Mixtures

Implementing sustainable weed control strategies is a major challenge in agriculture. Intercropping offers a potential solution to control weed pressure by reducing the niche space available for weeds; however, available research on the relationship between crop diversity and weed pressure, and its consequences on crop yield is not fully conclusive yet. In this study, we performed an extensive intercropping experiment using eight crop species and 40 different species mixtures to examine how crop diversity affects weed communities and how the subsequent changes in weeds influence crop yield. Field experiments were carried out in Switzerland and in Spain, which differ drastically in terms of climate and soil, and included monocultures, 2- and 4-species mixtures, and a control treatment without crops. Weed communities were assessed in terms of biomass, species richness and evenness, and community composition. Results indicate that intercropping per se does not reduce weed performance or diversity, but crop species composition does. In particular, the presence of cereals in crop mixtures significantly reduced weed biomass and diversity. Despite the lack of crop diversity effect on weeds, crop yield increased with crop species richness, particularly in Switzerland. Moreover, in Switzerland, where soil resources were abundant, increasing crop yield correlated with increased weed suppression and reduced weed diversity. In Spain, where water and nutrients were limited, crop yield was not related to weed biomass or diversity. Synthesis and applications: We demonstrate that in our study, increased crop yield in mixtures was not due to increased weed suppression in diverse crop communities, but must be the result of other ecological processes. We also show that crop-weed relationships vary across environmental conditions, which emphasizes the need for a better understanding of weed communities' assembly mechanisms, as well as locally adapted weed management strategies.

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How Important are Crop Spatial Pattern and Density for Weed Suppression by Spring Wheat?

Weed Science ◽

10.1614/ws-d-11-00172.1 ◽

2012 ◽

Vol 60 (3) ◽

pp. 501-509 ◽

Cited By ~ 26

Author(s):

Jannie Maj Olsen ◽

Hans-Werner Griepentrog ◽

Jon Nielsen ◽

Jacob Weiner

Keyword(s):

Spatial Pattern ◽

Biomass Production ◽

Spring Wheat ◽

Field Experiments ◽

Weed Suppression ◽

Total Biomass ◽

Weed Biomass ◽

Spatial Uniformity ◽

Crop Density ◽

Crop Biomass

Previous research has shown that both the density and spatial pattern of wheat have an influence on crop growth and weed suppression, but it is not clear what degree of uniformity is necessary to achieve major improvements in weed suppression. Field experiments were performed over 3 yr to investigate the effects of crop density and different spatial distributions on weed suppression. The spatial pattern of spring wheat sown in five patterns and three densities in small weed-infested plots were analyzed with the use of digitized photographs of field plots to describe the locations of individual wheat plants asxandycoordinates. We used a simple quantitative measure, Morisita's index, to measure the degree of spatial uniformity. Increased crop density resulted in reduced weed biomass and increased crop biomass every year, but crop pattern had significant effects on weed and crop biomass in the first year only. Weather conditions during the second and third years were very dry, resulting in very low weed biomass production. We hypothesize that water deficiency increased the importance of belowground relative to aboveground competition by reducing biomass production, making competition more size symmetric, and reducing the effect of crop spatial pattern on weed growth. The results indicate that increased crop density in cereals can play an important role in increasing the crop's competitive advantage over weeds, and that spatial uniformity maximizes the effect of density when low resource levels or abiotic stress do not limit total biomass production.

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Processing Tomato and Weed Response to Flufenacet plus Metribuzin

Weed Technology ◽

10.1614/wt00-204 ◽

2004 ◽

Vol 18 (3) ◽

pp. 801-809 ◽

Cited By ~ 2

Author(s):

Peter H. Sikkema ◽

Allan S. Hamill ◽

Mirwais M. Qaderi ◽

Colleen Doucet

Keyword(s):

Weed Control ◽

Field Experiments ◽

Weed Species ◽

Early Season ◽

Commercial Formulation ◽

Common Lambsquarters ◽

Processing Tomato ◽

Redroot Pigweed ◽

Application Rates ◽

Green Foxtail

Field experiments were conducted in 1998, 1999, and 2000 at two locations (Harrow and Ridgetown) in southwestern Ontario to determine the biologically effective rates (I90) of a commercial formulation of flufenacet plus metribuzin for weed control and processing tomato tolerance. At the proposed label use rate, flufenacet plus metribuzin provided excellent (≥90%) early-season (22 to 29 d after planting) control of velvetleaf, good (80 to 89%) control of barnyardgrass and redroot pigweed, and fair (60 to 79%) control of common lambsquarters. Flufenacet plus metribuzin provided fair late-season (59 to 97 d after planting) control of redroot pigweed and common lambsquarters and poor (≤59%) control of barnyardgrass and velvetleaf. At Harrow and Ridgetown, I90values for early-season weed control ranged from 70 to 1,300 g ai/ha and 50 to 1,900 g ai/ha, respectively. Flufenacet plus metribuzin provided poor weed control at Ridgetown. This result was not attributable to higher weed density or particular weed species but may have been caused by lack of rainfall and too low application rates for the medium-textured soil type. It is estimated that flufenacet plus metribuzin at 1,400 g/ha can control green foxtail season-long, whereas barnyardgrass and common lambsquarters would require 1,900 g/ha. Season-long control of velvetleaf and redroot pigweed would require application rates of 3,200 and 7,100 g/ha, respectively. Only slight early-season crop injury was observed, which was not reflected in yields. Optimum yields of tomatoes were obtained at Harrow at rates lower or slightly higher than the registered rates for corn and soybean. Tomato yields were higher at Harrow than at Ridgetown, which may have been due to differences in soil texture. Tomatoes grown in a medium-textured (Ridgetown) soil appeared to be less competitive against weeds than those grown in a coarse-textured soil (Harrow).

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