Sustainability, conservation tillage and weeds in Canada

1996 ◽  
Vol 76 (4) ◽  
pp. 651-659 ◽  
Author(s):  
D. A. Derksen ◽  
R. E. Blackshaw ◽  
S. M. Boyetchko
Keyword(s):  
Biological Control ◽  
Weed Management ◽  
Conservation Tillage ◽  
The United States ◽  
Integrated Weed Management ◽  
Biological Weed Control ◽  
Plant Residues ◽  
Tillage Systems ◽  
Weed Communities ◽  
Inundative Biological Control

The sustainability of conservation tillage is dependent on the extent of changes in weed community composition, the usage of herbicides, and the development of integrated weed management (IWM) strategies, including biological weed control. The objective of this paper is to review research on conservation tillage and weed management in light of these factors. Recent Canadian research has found that changes in weed communities due to the adoption of conservation tillage are not necessarily those expected and were not consistant by species, location, or year. Changes reflected the use of different selection pressures, such as different crop rotations and herbicides, within the studies to a greater extent than weed life cycle groupings. Therefore, research that determines the reasons for change or the lack of change in weed communities is required to provide the scientific basis for the development of IWM strategies. Documented herbicide usage in conservation tillage varies from less than to more than conventional-tillage systems. Potential to reduce herbicide usage in conservation-tillage systems exists. Furthermore, the herbicides used in western Canada are different from those causing ground water contamination in the United States, are less volatile, and are used at lower rates. The presence of surface crop residues in conservation tillage may provide a unique environment for classical and inundative biological control agents. Some insects, fungi, and bacteria have the potential to survive to a greater extent in undisturbed plant residues. Residue management and conservation tillage systems are evolving in Canada. Research must keep pace by providing weed management strategies that enchance the sustainability of these systems. Key words: Biological control, zero tillage, integrated weed management, residues, herbicides, rhizobacteria.

scholarly journals Principles of Biological Weed Control

HortScience ◽  
1995 ◽  
Vol 30 (4) ◽  
pp. 750D-750
Author(s):  
Susan M. Boyetchko
Keyword(s):  
Biological Control ◽  
Weed Management ◽  
Fungal Pathogens ◽  
The United States ◽  
Reproductive Capacity ◽  
Biological Weed Control ◽  
Weed Biocontrol ◽  
Weed Growth ◽  
Inundative Biological Control ◽  
High Concentrations

Weeds continue to have a tremendous impact on crop yield losses in Canada and the United States, despite efforts to control them with chemicals. Biological control offers an additional means for reducing weed populations while reducing the reliance of the agri-food industry on chemical pesticides. Effective biological strategies that are compatible with good soil conservation practices would benefit farmers while maintaining environmental quality and a sustained production for the future. Inundative biological control of weeds with microbial agents involves the mass production and application of high concentrations of a plant pathogen to a target weed. Historically, biocontrol agents used on weeds have been foliar fungal pathogens. More recently, the soil has become a source for microorganisms, such as rhizobacteria, for development as biological control agents. Several naturally occurring rhizobacteria have weed suppressive properties, where growth and development of weeds such as downy brome, wild oats, leafy spurge, and green foxtail are significantly inhibited. Although the focus in weed biocontrol has been on the eradication of weeds, rhizobacteria may be used to improve seedling establishment of the crop by reducing the weed competition. This can be achieved through a reduction in weed growth, vigor, and reproductive capacity and improvement in the ability of the crop to compete with the weed. Current research in weed biocontrol with microorganisms and its application to weed management systems will be discussed.

An Integrated Weed Management Approach to Managing Foxtail Barley (Hordeum jubatum) in Conservation Tillage Systems

1999 ◽  
Vol 13 (2) ◽  
pp. 347-353 ◽  
Author(s):  
Robert E. Blackshaw ◽  
Greg Semach ◽  
Xiangju Li ◽  
John T. O'Donovan ◽  
K. Neil Harker
Keyword(s):  
Crop Yield ◽  
Weed Management ◽  
Conservation Tillage ◽  
Wheat Yield ◽  
Integrated Weed Management ◽  
Management Approach ◽  
Row Spacing ◽  
Seeding Rate ◽  
Tillage Systems ◽  
Perennial Plants

A 4-yr field experiment was conducted to determine the merits of combining cultural and chemical controls to manage foxtail barley in reduced-tillage systems. Factors studied were crop row spacing, seeding rate, and application rate and timing of glyphosate within a spring wheat-flax cropping sequence. Glyphosate applied preseeding at 400 or 800 g/ha killed foxtail barley seedlings but only suppressed established perennial plants. Glyphosate applied postharvest at 800 g/ha killed 60 to 70% of established plants. Combinations of preseeding and postharvest glyphosate gave the greatest reductions in foxtail barley biomass and seed production and resulted in the greatest increases in crop yield. Including flax in the rotation allowed use of grass herbicides such as quizalofop or sethoxydim that effectively controlled foxtail barley seedlings and provided some suppression of perennial plants. An increase in wheat seeding rate from 75 to 115 kg/ha reduced foxtail barley growth and increased wheat yield in 3 of 4 yr. Increasing the flax seeding rate from 40 to 80 kg/ha or reducing wheat and flax row spacing from 30 to 20 cm provided little benefit in managing foxtail barley or increasing crop yield. A multiyear approach combining agronomic practices and timely use of herbicides should allow growers to effectively manage foxtail barley in annual cropping systems using conservation tillage.

Weed response and crop growth in winter wheat–lucerne intercropping: a comparison of conventional and reduced soil-tillage conditions in northern France

2017 ◽  
Vol 68 (11) ◽  
pp. 1070 ◽  
Author(s):  
E. Barilli ◽  
M.-H. Jeuffroy ◽  
J. Gall ◽  
S. de Tourdonnet ◽  
S. Médiène
Keyword(s):  
Winter Wheat ◽  
Weed Control ◽  
Weed Management ◽  
Conservation Tillage ◽  
Group Analysis ◽  
Soil Tillage ◽  
Integrated Weed Management ◽  
Living Mulch ◽  
Wheat Production ◽  
Weed Communities

Changing agricultural practices from conventional to conservation tillage generally leads to increased weed populations and herbicide use. To gain information about the possible use of lucerne (Medicago sativa L.) cover crop as an alternative and sustainable weed-control strategy for winter wheat (Triticum aestivum L.), an experiment was performed at Thiverval-Grignon, France, from 2008 to 2010. We compared conventional and reduced tillage as well as the presence and absence of living mulch (i.e. lucerne) on weeds and wheat production. Percentage soil coverage and aboveground biomass of wheat, lucerne and weeds were measured at the end of grain filling. Weed communities were analysed in terms of composition and diversity. During both seasons, wheat biomass did not significantly decrease in reduced-till trials compared with conventional ones (7.0 and 7.2 t ha–1, respectively, in 2008–09; 6.9 and 7.1 t ha–1 in 2009–10). Regardless of soil management, the percentage soil coverage by wheat significantly decreased when it was intercropped, although wheat biomass was not significantly reduced compared with the sole crop. To minimise cash-crop losses, we studied the competition between wheat, lucerne and weeds, testing various herbicide strategies. Early control of lucerne allowed better balance between weed control and wheat development. In addition, weed communities varied among treatments in terms of abundance and composition, being reduced but more varied in plots associated with lucerne. A functional group analysis showed that grasses benefited from reduced-till conditions, whereas problematic weeds such as annuals with creeping and climbing morphologies were substantially reduced. In addition, annual and perennial broad-leaf species with rosette morphology were also significantly decreased when lucerne was used as living mulch. Wheat production in reduced-till conditions intercropped with lucerne living mulch may be useful for integrated weed management, reducing the need for herbicides.

scholarly journals The Effect of Different Soil Tillage Systems and Crop Residues on the Composition of Weed Communities

Agronomy ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1276
Author(s):  
Vaida Steponavičienė ◽  
Aušra Marcinkevičienė ◽  
Lina Marija Butkevičienė ◽  
Lina Skinulienė ◽  
Vaclovas Bogužas
Keyword(s):  
Soil Ph ◽  
Crop Residues ◽  
Soil Tillage ◽  
Reduced Tillage ◽  
Plant Residues ◽  
No Tillage ◽  
Agricultural Crops ◽  
Weed Species ◽  
Tillage Systems ◽  
Weed Communities

The composition of weed communities in agricultural crops is dependent on soil properties and the applied agronomic practices. The current study determined the effect of different tillage systems and crop residue on the soil weed community composition. The research programme encompassed 2013–2015 in a long-term field experiment located in the Experimental Station of Vytautas Magnus University in Lithuania. The soil type in the experimental field was qualified as Endocalcaric Stagnosol (Aric, Drainic, Ruptic, Amphisiltic). Weeds were categorised into communities according to soil pH, nitrogen and moisture indicators. The results of investigations were grouped using cluster analysis. Agricultural crops were dominated by different weed species depending on the soil pH and moisture. Weed species were relatively more frequent indicating nitrogen-rich and very nitrogen-rich soils. In the reduced tillage and no-tillage systems, an increase in the abundance of weed species indicating moderate acidity and low acidity, moderately wet and wet, nitrogen-rich and very nitrogen-rich soils was observed. The application of plant residues decreased the weed species abundance. In the reduced tillage and no-tillage systems, the quantitative distribution of weed was often uneven. By evaluating the association of weed communities with groups of different tillage systems with or without plant residues, their control can be optimised.

Halauxifen-methyl controls glyphosate-resistant horseweed (Conyza canadensis) but not giant ragweed (Ambrosia trifida) in winter wheat

2020 ◽  
Vol 34 (4) ◽  
pp. 607-612 ◽  
Author(s):  
Jessica Quinn ◽  
Nader Soltani ◽  
Jamshid Ashigh ◽  
David C. Hooker ◽  
Darren E. Robinson ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Weed Management ◽  
Field Experiments ◽  
The United States ◽  
Integrated Weed Management ◽  
Conyza Canadensis ◽  
Limited Information ◽  
Weed Species ◽  
Ambrosia Trifida ◽  
Giant Ragweed

AbstractHorseweed is a competitive summer or winter annual weed that produces up to 230,000 small seeds per plant that are capable of traveling more than 500 km via wind. Giant ragweed is a tall, highly competitive summer annual weed. Glyphosate-resistant (GR) horseweed and GR giant ragweed pose significant challenges for producers in the United States and Ontario, Canada. It is thought that an integrated weed management (IWM) system involving herbicide rotation is required to control GR biotypes. Halauxifen-methyl is a new selective broadleaf POST herbicide registered for use in cereal crops; there is limited information on its efficacy on horseweed and giant ragweed. The purpose of this research was to determine the efficacy of halauxifen-methyl applied POST, alone and in a tank mix, for the control of GR horseweed and GR giant ragweed in wheat across southwestern Ontario. For each weed species, an efficacy study consisting of six field experiments was conducted over a 2-yr period (2018, 2019). At 8 wk after application (WAA), halauxifen-methyl, fluroxypyr/halauxifen-methyl, fluroxypyr/halauxifen-methyl + MCPA EHE, fluroxypyr + MCPA ester, 2,4-D ester, clopyralid, and pyrasulfotole/bromoxynil + ammonium sulfate controlled GR horseweed >95%. Fluroxypyr and MCPA provided only 86% and 37% control of GR horseweed, respectively. At 8 WAA, fluroxypyr, fluroxypyr/halauxifen-methyl, fluroxypyr/halauxifen-methyl + MCPA EHE, fluroxypyr + MCPA ester, fluroxypyr/halauxifen-methyl + MCPA EHE + pyroxsulam, 2,4-D ester, clopyralid, and thifensulfuron/tribenuron + fluroxypyr + MCPA ester controlled GR giant ragweed 87%, 88%, 90%, 94%, 96%, 96%, 98%, and 93%, respectively. Halauxifen-methyl and pyroxsulam provided only 45% and 28% control of GR giant ragweed, respectively. Halauxifen-methyl applied alone POST in the spring controlled GR horseweed but not GR giant ragweed in winter wheat.

Integrated Management of Scotch Broom (Cytisus scoparius) Using Biological Control

2012 ◽  
Vol 5 (1) ◽  
pp. 69-82 ◽  
Author(s):  
Angelica M. Herrera-Reddy ◽  
Raymond I. Carruthers ◽  
Nicholas J. Mills
Keyword(s):  
Biological Control ◽  
Seed Production ◽  
Seed Bank ◽  
Weed Management ◽  
Biological Control Agent ◽  
Integrated Management ◽  
Management Strategies ◽  
Integrated Weed Management ◽  
Scotch Broom ◽  
Mature Seeds

AbstractIntegrated weed management strategies (IWM) are being advocated and employed to control invasive plants species. In this study, we compared three management strategies (biological control alone [BC], BC with fire [BC + F], and BC with mowing [BC + M]) to determine if physical controls reduce seed production by Scotch broom and interfere with the action of the biological control agent—the Scotch broom seed weevil. We measured seed production and seed predation by the weevil at both pod and plant scale, and seed bank density over two field seasons. We found no difference in the number of seeds per pod among management strategies. However, combining management strategies (BC + M and BC + F) resulted in significant reductions in pods per plant, mature seeds per plant, and seed bank density relative to biological control alone. We did not find differences among management strategies in number of weevils per pod or proportion of seeds predated by the weevil at either pod or whole-plant scale. However, combining management strategies (BC + M and BC + F) resulted in a significant reduction in healthy mature seeds per plant relative to biological control alone. Although both integrated strategies outperformed biological control alone in reducing seed production and the seed bank, with no statistical difference between them, we propose that short-rotation prescribed fire could prove to be a more effective strategy for long-term management of Scotch broom due to its potential for slightly greater depletion of the seed bank.

Alternative weed management strategies in conservation tillage systems for white beans (Phaseolus vulgaris L.)

1998 ◽  
Vol 78 (2) ◽  
pp. 363-370 ◽  
Author(s):  
David C. Hooker ◽  
Tony J. Vyn ◽  
Clarence J. Swanton
Keyword(s):  
Phaseolus Vulgaris ◽  
Weed Management ◽  
Conservation Tillage ◽  
Management Strategies ◽  
First Year ◽  
Tillage Systems ◽  
No Till ◽  
White Bean ◽  
Chisel Plow ◽  
Moldboard Plow

White bean producers often perceive that increased herbicide inputs are required with the adoption of conservation tillage. Acceptance of conservation tillage systems for this crop would increase if effective weed management practices were assured. In 1991 and 1992, various weed management strategies were evaluated in white bean (Phaseolus vulgaris L.) grown with three tillage systems at two sites in southern Ontario. Experiments were newly established each year following corn harvested for grain. Primary tillage treatments were fall moldboard plowing, fall chisel plowing, and first-year no-till. Combinations of mechanical weeding, metobromuron [3–(4–bromophenyl)–1–methoxy–1–methylurea] herbicide broadcasted at two rates, and a band application of the herbicide were investigated in each tillage system. Timely rotary hoeing reduced weed numbers in moldboard plow and chisel plow treatments, but was not effective in no-till. Weeds were adequately controlled in all tillage systems with mechanical treatments following a herbicide either broadcasted at a reduced rate or banded over the crop row. Metobromuron broadcasted at the full recommended rate alone controlled weeds in no-till; in contrast, the degree of weed control was poor without mechanical cultivation in both moldboard and chisel plow systems. Integrating mechanical and chemical control methods was more beneficial in tilled systems. Overall weed populations were lower in first-year no-till than moldboard plow or chisel plow tillage systems. White bean producers who adopt conservation tillage under conditions similar to those investigated can be assured of effective weed management alternatives as well as bean yields equivalent to conventional tillage. Key words: Conservation tillage, weed management, rotary hoe, inter-row cultivation, Phaseolus vulgaris

scholarly journals The intersection of integrated pest management and soil quality in the resistant weed era

2021 ◽  
Author(s):  
Audrey V. Gamble ◽  
Andrew J. Price
Keyword(s):  
United States ◽  
Soil Quality ◽  
Weed Control ◽  
Conservation Tillage ◽  
The United States ◽  
Soil Tillage ◽  
Soil Productivity ◽  
Weed Seed ◽  
Tillage Systems ◽  
Herbicide Resistant

Agricultural producers and scientists have long recognized both beneficial and detrimental aspects of soil tillage. With the development and adoption of herbicide-resistant crops, particularly glyphosate-resistant crops, herbicides such as glyphosate replaced the need for tillage either before or after crop planting. Thus, tillage has become less important for weed management and has been a primary enabler for the success of the majority of conservation production systems. Currently, herbicide-resistant and troublesome weeds are continually challenging agricultural decisions throughout the world. Conservation tillage hectarage are at constant risk of being converted to higher-intensity tillage systems due to lack of weed control. The shift to higher-intensity tillage facilitates burial of weed seed through use of inversion tillage and/or use of surface tillage to facilitate preplant incorporated and preemergence herbicides for control of herbicide resistant or troublesome weeds, especially in non-irrigated production. For example, Palmer amaranth (Amaranthus palmeri) has become the dominant weed problem in United States row crop production because of evolved resistance to glyphosate. Inversion tillage was clearly demonstrated to be an effective tool in helping the management of this weed. However, there is no question that most tillage operations promote soil loss, adversely affect (lower) surface water quality, and negatively impact soil productivity. Depending on the severity of the herbicide-resistant or troublesome weed infestation, multiple strategies involving integration of cultural as well as chemical weed control will be needed to overcome the need for tillage. Utilizing high biomass conservation tillage systems, such as those used extensively in South America and introduced to the United States, can help reduce the emergence of weeds by suppressing weed germination and growth. When the winter cover crop is planted early and managed for maximum growth, a dense mat is formed on the soil surface. Because weed emergence and growth are suppressed by the physical barrier and shading provided by the residue, more residue results in increased weed control. Conservation tillage systems that minimize soil disturbance (direct seeding or minimum tillage) can further reduce weed seed germination. In addition, allelopathy plays a role in weed suppression, but quantifying allelopathic effects in applied research is rarely accomplished. Creative research programs have been developed that meet conservation compliance requirements and at the same time judiciously use tillage as an element for management of resistant or troublesome species. Similar programs are needed to help manage other herbicide resistant or troublesome weed species in other regions and cropping systems. Further research is critically needed in instances when few or no other options are available to ensure the economic viability of farming operations while addressing long-term soil quality concerns.

Herbicide Technology for Integrated Weed Management Systems

Weed Science ◽  
1982 ◽  
Vol 30 (S1) ◽  
pp. 35-39 ◽  
Author(s):  
G. D. Hill
Keyword(s):  
Weed Management ◽  
Agricultural Production ◽  
Food Production ◽  
Critical Period ◽  
The United States ◽  
Integrated Weed Management ◽  
Strong Impact ◽  
Integrated Crop Management ◽  
Economic Forces ◽  
Timely Topic

I am honored by your invitation to participate in a symposium on this timely topic. Our twenty-first annual meeting on weed science and technology comes during a critical period of challenging readjustment for agricultural production in the world, especially in the United States. To focus perspective on this subject, I have compiled a list of factors, trends, and economic forces that can exert a strong impact on the future of agriculture, food production, herbicide technology, and integrated crop-management programs during the next 20 yr.

Tillage, fertiliser and glyphosate timing effects on foxtail barley (Hordeum jubatum) management in wheat

2000 ◽  
Vol 80 (3) ◽  
pp. 655-660 ◽  
Author(s):  
R. E. Blackshaw ◽  
G. Semach ◽  
X. Li ◽  
J. T. O'Donovan ◽  
K. N. Harker
Keyword(s):  
Weed Management ◽  
Production Systems ◽  
Conservation Tillage ◽  
Wheat Yield ◽  
Soil Surface ◽  
Integrated Weed Management ◽  
Canadian Prairies ◽  
Application Timing ◽  
Hordeum Jubatum ◽  
Timing Effects

Foxtail barley (Hordeum jubatum L.) is becoming a more severe weed problem as conservation tillage becomes widely adopted on the southern Canadian prairies. A 5-yr field study was conducted to determine the combined effects of tillage, N rate, N placement and application timing of glyphosate to manage foxtail barley in spring wheat. Wide-blade tillage conducted in fall and spring, compared to zero-till, reduced foxtail barley biomass and seed production in all yr and increased wheat yield in 4 of 5 yr. Foxtail barley was highly competitive with wheat for added N. N fertiliser placed mid-row in 10-cm-deep bands reduced foxtail barley growth in 2 of 5 yr and increased wheat yield in 3 of 5 yr compared with soil surface broadcast N. Wheat yield sometimes was similar when N was banded at 60 kg ha−1 or broadcast at 120 kg ha−1, indicating the large advantage of banding N in some situations. Glyphosate at 800 g ha−1 applied preharvest or postharvest gave similar levels of foxtail barley control in 2 of 3 yr. Results indicate that foxtail barley can be adequately managed in wheat production systems utilizing conservation tillage. Key words: Foxtail barley, Hordeum jubatum, glyphosate, integrated weed management, nitrogen placement, zero tillage

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