Non-Chemical Weed Management in Vegetables by Using Cover Crops: A Review

Vegetables are a substantial part of our lives and possess great commercial and nutritional value. Weeds not only decrease vegetable yield but also reduce their quality. Non-chemical weed control is important both for the organic production of vegetables and achieving ecologically sustainable weed management. Estimates have shown that the yield of vegetables may be decreased by 45%–95% in the case of weed–vegetable competition. Non-chemical weed control in vegetables is desired for several reasons. For example, there are greater chances of contamination of vegetables by herbicide residue compared to cereals or pulse crops. Non-chemical weed control in vegetables is also needed due to environmental pollution, the evolution of herbicide resistance in weeds and a strong desire for organic vegetable cultivation. Although there are several ways to control weeds without the use of herbicides, cover crops are an attractive choice because these have a number of additional benefits (such as soil and water conservation) along with the provision of satisfactory and sustainable weed control. Several cover crops are available that may provide excellent weed control in vegetable production systems. Cover crops such as rye, vetch, or Brassicaceae plants can suppress weeds in rotations, including vegetables crops such as tomato, cabbage, or pumpkin. Growers should also consider the negative effects of using cover crops for weed control, such as the negative allelopathic effects of some cover crop residues on the main vegetable crop.

Download Full-text

Progress towards no-till organic weed control in western Canada

Renewable Agriculture and Food Systems ◽

10.1017/s1742170511000500 ◽

2012 ◽

Vol 27 (1) ◽

pp. 60-67 ◽

Cited By ~ 31

Author(s):

Steven J. Shirtliffe ◽

Eric N. Johnson

Keyword(s):

Weed Control ◽

Faba Bean ◽

Cover Crops ◽

Green Manure ◽

Crop Residues ◽

Organic Production ◽

Field Pea ◽

Western Canada ◽

No Till ◽

Green Manure Crops

AbstractOrganic farmers in western Canada rely on tillage to control weeds and incorporate crop residues that could plug mechanical weed-control implements. However, tillage significantly increases the risk of soil erosion. For farmers seeking to reduce or eliminate tillage, potential alternatives include mowing or using a roller crimper for terminating green manure crops (cover crops) or using a minimum tillage (min-till) rotary hoe for mechanically controlling weeds. Although many researchers have studied organic crop production in western Canada, few have studied no-till organic production practices. Two studies were recently conducted in Saskatchewan to determine the efficacy of the following alternatives to tillage: mowing and roller crimping for weed control, and min-till rotary hoeing weed control in field pea (Pisum sativum L.). The first study compared mowing and roller crimping with tillage when terminating faba bean (Vicia faba L.) and field pea green manure crops. Early termination of annual green manure crops with roller crimping or mowing resulted in less weed regrowth compared with tillage. When compared with faba bean, field pea produced greater crop biomass, suppressed weeds better and had less regrowth. Wheat yields following pea were not affected by the method of termination. Thus, this first study indicated that roller crimping and mowing are viable alternatives to tillage to terminate field pea green manure crops. The second study evaluated the tolerance and efficacy of a min-till rotary harrow in no-till field pea production. The min-till rotary hoe was able to operate in no-till cereal residues and multiple passes did not affect the level of residue cover. Field pea exhibited excellent tolerance to the min-till rotary hoe. Good weed control occurred with multiple rotary hoe passes, and pea seed yield was 87% of the yield obtained in the herbicide-treated check. Therefore, this second study demonstrated that min-till rotary hoeing effectively controls many small seeded annual weeds in the presence of crop residue and thus can reduce the need for tillage in organic-cropping systems.

Download Full-text

Burning Nettle, Common Purslane, and Rye Response to a Clove Oil Herbicide

Weed Technology ◽

10.1614/wt-05-137r1.1 ◽

2006 ◽

Vol 20 (3) ◽

pp. 646-650 ◽

Cited By ~ 26

Author(s):

Nathan S. Boyd ◽

Eric B. Brennan

Keyword(s):

Weed Management ◽

Production Systems ◽

Dry Weight ◽

Organic Production ◽

Management Tool ◽

Vegetable Production ◽

Clove Oil ◽

Organic Farms ◽

High Concentrations ◽

Common Purslane

Weed management is often difficult and expensive in organic production systems. Clove oil is an essential oil that functions as a contact herbicide and may provide an additional weed management tool for use on organic farms. Burning nettle, purslane, and rye responses to 5, 10, 20, 40, and 80% v/v clove oil mixture applied in spray volumes of 281 and 468 L/ha were examined. Log-logistic curves were fitted to the nettle and purslane data to determine the herbicide dose required to reduce plant dry weight 50% (GR50) and 90% (GR90). A three-parameter Gaussian curve was fitted to the rye data. The GR50 and GR90 were largely unaffected by spray volume. Nettle dry weight was reduced by 90% with 12 to 61 L clove oil/ha, whereas 21 to 38 L clove oil/ha were required to reduce purslane biomass to the same level. Rye was not effectively controlled by clove oil. Clove oil controls broadleaf weeds at high concentrations, but its cost makes broadcast applications prohibitive, even in high-value vegetable production systems.

Download Full-text

No-till Vegetable Production—Its Time is Now

HortTechnology ◽

10.21273/horttech.9.3.373 ◽

1999 ◽

Vol 9 (3) ◽

pp. 373-379 ◽

Cited By ~ 20

Author(s):

Ronald D. Morse

Keyword(s):

Cover Crops ◽

Weed Management ◽

Production Systems ◽

Control Strategies ◽

Soil Surface ◽

Integrated Weed Management ◽

Vegetable Production ◽

Vegetable Crops ◽

No Till ◽

Minimum Disturbance

Advantages of no-till (NT) production systems are acknowledged throughout the world. During the 1990s, production of NT vegetable crops has increased for both direct seeded and transplanted crops. Increased interest in reduced-tillage systems among research workers and vegetable growers is attributed to: 1) development and commercialization of NT transplanters and seeders, 2) advancements in the technology and practice of producing and managing high-residue cover crop mulches, and 3) improvements and acceptance of integrated weed management techniques. Results from research experiments and grower's fields over the years has shown that success with NT transplanted crops is highly dependent on achieving key production objectives, including: 1) production of dense, uniformly distributed cover crops; 2) skillful management of cover crops before transplanting, leaving a heavy, uniformly distributed killed mulch cover over the soil surface; 3) establishment of transplants into cover crops with minimum disturbance of surface residues and surface soil; and 4) adoption of year-round weed control strategies.

Download Full-text

Potential of Rye (Secale cereale) for Weed Management in Transplant Tomatoes (Lycopersicon esculentum)

Weed Science ◽

10.1017/s0043174500094406 ◽

1996 ◽

Vol 44 (3) ◽

pp. 596-602 ◽

Cited By ~ 19

Author(s):

Reid J. Smeda ◽

Stephen C. Weller

Keyword(s):

Weed Control ◽

Cover Crops ◽

Weed Management ◽

Production Systems ◽

Weed Suppression ◽

Management Technique ◽

Bare Ground ◽

Tomato Production ◽

Tomato Yield ◽

Weed Growth

Weed control in tomato production systems is difficult because few are registered. The use of rye for weed control and its influence on transplant tomato yields was investigated during 1986 and 1987 at two locations in IN to determine if cover crops can provide an alternative weed management technique. ‘Wheeler’ rye was sown in the fall of 1985 and 1986, and mowed or desiccated with glyphosate at various times before planting ‘IND 812'tomatoes. At the time of glyphosate application, rye residues reduced the growth of overwintering weeds by 93% or more compared to bare ground (no cover crop) areas. The time of desiccating rye prior to planting tomatoes affected the extent of weed suppression by rye residues. In 1986, rye treated 4 wk before planting (WBP) tomatoes provided up to 89% suppression of weed growth at 2 wk after planting (WAP) tomatoes, but no measurable weed suppression 5 WAP tomatoes. Rye treated 2 WBP tomatoes provided up to 97% weed suppression up to 5 WAP tomatoes. In 1987, weed suppression varied between locations and differed from 1986. At Lafayette, rye treated 2 and 1 WBP tomatoes provided greater than 81% suppression of weed growth up to 8 WAP tomatoes. Rye mowed and the residues placed into a plot at a known density also reduced weed growth (60%) 8 WAP tomatoes. At Vincennes, however, rye treated 2 and 1 WBP in 1987 did not reduce weed growth later than 4 WAP tomatoes compared to the unweeded, bare ground treatment. The mowed rye residues at Vincennes suppressed weed growth (96%) up to 8 WAP tomatoes. Tomato yield was correlated to weed suppression. In 1986, tomato yield in the rye treated 2 WBP tomatoes was comparable to yield in the bare ground, weeded controls. However, tomato yield in rye plots treated 4 WBP tomatoes was similar to yield in the bare ground, unweeded control. In 1987, tomato yields in all rye plots (mowed, treated 2 and 1 WBP tomatoes) were similar to tomato yields in the bare ground, weeded control at Lafayette. At Vincennes, only the mowed rye treatment yielded comparably to the bare ground, weeded control. In general, rye plots that were weeded yielded similar to or up to 28% more than a bare ground, weeded control. Tomato yields were not reduced by rye residues. Tomato yields in rye residues that provided effective suppression of weed growth (greater than 80%) for a minimum of 4 to 5 WAP tomatoes were comparable to bare ground, weeded controls.

Download Full-text

Synthetic Mulches in Organic Hardneck Garlic (Allium sativum subsp. ophioscorodon) Production

USURJ University of Saskatchewan Undergraduate Research Journal ◽

10.32396/usurj.v6i2.435 ◽

2020 ◽

Vol 6 (2) ◽

Author(s):

Matthew A Carr ◽

Kate A Congreves

Keyword(s):

Weed Control ◽

Allium Sativum ◽

Production Systems ◽

Block Design ◽

Cropping System ◽

Organic Production ◽

Soil Conditions ◽

Vegetable Production ◽

Soil Nutrition ◽

Certified Organic

The demand for certified organic garlic (Allium sativum) in Canada is increasing; however, garlic can be challenging to produce organically, as it does not compete well with weeds, requires relatively fertile soils, and is grown in a biennial cropping system. Synthetic mulches have been adopted in organic production as they can be an economical method to improve vegetable production by reducing weed pressure and modifying soil conditions. We hypothesize that garlic quality and overall yield will be improved when using synthetic mulches. In 2017-18, we conducted a randomized complete block design experiment to compare garlic production of black plastic, white plastic, and Kraft paper mulch treatments to a control with no mulch at a certified organic farm in Krestova, British Columbia. We evaluated garlic characteristics associated with yield and quality, changes in soil nutrition, and weed control of the mulch treatments. We found that plastic mulches had the best weed control, and all synthetic mulches increased minimum and maximum bulb diameter, clove count, and yield compared to the control. Mulching materials did not influence soil nitrate concentrations. The results support the hypothesis that synthetic mulches increase the quality and yield of the garlic compared to the control. Our findings suggest that synthetic mulching may be a key component of improving garlic production systems.

Download Full-text

Stale Seedbed Techniques for Organic Vegetable Production

Weed Technology ◽

10.1614/wt-05-109.1 ◽

2006 ◽

Vol 20 (4) ◽

pp. 1052-1057 ◽

Cited By ~ 38

Author(s):

Nathan S. Boyd ◽

Eric B. Brennan ◽

Steve A. Fennimore

Keyword(s):

Weed Control ◽

Weed Management ◽

Production Systems ◽

Production Costs ◽

Vegetable Production ◽

Clove Oil ◽

Herbicide Application ◽

Management Tools ◽

Organic Vegetable Production ◽

The Difference

Weed control in organic vegetable production systems is challenging and accounts for a large portion of production costs. Six methods to prepare a stale seedbed were compared on certified and transitional organic land in Salinas, CA, in 2004. Weed control operations occurred on raised beds 2 to 3 d before planting baby spinach or a simulated vegetable planting. A flamer and an herbicide application of 10% v/v of a clove oil mixture (45% v/v clove oil) at 280 L/ha (iteration 1) or 15% v/v of a clove oil mixture (45% clove oil) at 467 L/ha (iterations 2 and 3) were used to control weeds without disturbing the soil. Top knives on a sled, a rolling cultivator, and a rotary hoe were used to control weeds while tilling the bed top. A bed shaper–rototiller combination was also used, which tilled the entire bed. Broadleaf weed control was 36% with clove oil, 63% with the rotary hoe, and significantly higher (87 to 100% control) with the remaining treatments in iteration 1. Broadleaf weed control was consistently lower (72 to 86% control) with the flamer than all other treatments (95 to 100% control) in iterations 2 and 3. The difference between sites can probably be attributed to differences in weed size. The flamer and the clove oil herbicide had the lowest number of weeds emerging with the crop following stale seedbed formation. The most expensive technique was clove oil at $1,372/ha. The estimated cost of forming the stale seedbed with the remaining weed management tools ranged from $10 to $43/ha.

Download Full-text

Evaluation of Organic Herbicides

HortScience ◽

10.21273/hortsci.39.4.876b ◽

2004 ◽

Vol 39 (4) ◽

pp. 876B-876 ◽

Cited By ~ 7

Author(s):

James Ferguson*

Keyword(s):

Weed Control ◽

Cover Crops ◽

Production Systems ◽

Organic Production ◽

Clove Oil ◽

Weed Species ◽

Central Florida ◽

Application Rates ◽

Citrus Rootstock ◽

Annual Grasses

Cover crops, cultivation, flaming, soil solarization, and mulching are commonly used for weed control in organic production systems. However, several new herbicides, approved by the Organic Materials Review Institute (OMRI), are recommended as contact, non-selective, post-emergence herbicides for annual grasses and broadleaf weeds. Citric acid (Alldown), clove oil (Matran 2), thyme/clove oil (XPRESS) were compared with glyphosate (Roundup Pro), a systemic broad spectrum herbicide, at three sites in southern and north central Florida during September and October, 2003. Treatments varied at each site but included glyphosate (5% a.i. applied to runoff) organic herbicides at recommended rates (undiluted citrus acid at 61 L·ha-1; 10% clove oil at 76 L·ha-1; 10% clove oil/thyme oil at 76 L·ha-1) and at twice recommended concentrations and application rates. Grasses and broadleaf weed species were different at each site but included Alexander grass, bahia grass, Bermudagrass, carpetweed, crabgrass, hairy indigo, lambs quarters, Florida pusley, goatweed, nutsedge, pigweed, shrubby primrose willow, broadleaf signalgrass, southern sandbur, spurge, torpedograss, and citrus rootstock seedlings. Weed control with the organic herbicides at all three sites at recommended and at higher concentrations and rates was inconsistent, ranging from 10% to 40%, compared with 100% control with glyphosate. Labels for the organic herbicides generally specify application to actively growing weeds less than 10 cm tall, emphasizing their use as early season herbicides. Fall applications to larger weeds, some within the specified maturity and size range and others taller and producing seed, could partially explain poor weed control.

Download Full-text

Weed suppression in a broccoli–winter rye intercropping system

Weed Science ◽

10.1614/ws-03-031r ◽

2004 ◽

Vol 52 (2) ◽

pp. 281-290 ◽

Cited By ~ 30

Author(s):

D. C. Brainard ◽

R. R. Bellinder

Keyword(s):

Cover Crops ◽

Weed Management ◽

Field Experiments ◽

Production Systems ◽

Insect Pests ◽

Light Availability ◽

Weed Suppression ◽

Winter Rye ◽

Vegetable Production ◽

Rapid Emergence

Interseeded cover crops have the potential to maintain and improve soil quality, reduce the incidence of insect pests, and suppress weeds in vegetable production systems. However, the successful use of interseeded cover crops has been limited by their tendency to either inadequately suppress weeds or suppress both weeds and the crop. We hypothesized that in irrigated broccoli production, winter rye could suppress annual weeds through rapid emergence and shading, without adversely affecting the taller transplanted broccoli crop. In field experiments conducted in New York from 1999–2001, broccoli was cultivated at 0, 10, or 10 and 20 d after broccoli transplanting (DAT), with or without rye at the final cultivation. Rye interseeded at 0 DAT suppressed weeds and improved yields relative to unweeded controls but resulted in broccoli yield losses relative to weed-free controls in 2 of 3 years. Rye seeded at either 10 or 20 DAT did not reduce broccoli yields but had little effect on weeds for a given level of cultivation and resulted in Powell amaranth seed production of up to 28,000 seeds m−2. Rye interseeded at 0 DAT reduced light availability to weeds in 2000 but not in 2001 when Powell amaranth avoided shading from rye through rapid emergence and vertical growth. In greenhouse pot experiments, low temperatures for 7 d after seeding delayed the emergence of Powell amaranth by 3 d relative to rye and increased the suppression of Powell amaranth by rye from 61 to 85%. Our results suggest that winter rye may be more successfully integrated into broccoli production (1) when sown at higher densities, (2) in locations or seasons (e.g., spring) with lower initial temperatures, and (3) in combination with other weed management tools.

Download Full-text

Conservation Tillage for Vegetable Production

HortTechnology ◽

10.21273/horttech.4.2.129 ◽

1994 ◽

Vol 4 (2) ◽

pp. 129-135 ◽

Cited By ~ 23

Author(s):

G.D. Hoyt ◽

D.W. Monks ◽

T.J. Monaco

Keyword(s):

Cover Crops ◽

Weed Management ◽

Water Conservation ◽

Conservation Tillage ◽

Nutrient Recycling ◽

Chemical Properties ◽

Cultural Practice ◽

Vegetable Production ◽

Management Tools ◽

Soil Temperatures

Conservation tillage is an effective sustainable production system for vegetables. No-till planters and transplanters and strip-till cultivation equipment are presently available for most vegetables. Lack of weed management tools (herbicides, cultivators, etc.) continues to be the cultural practice that limits adaptability of some vegetables to conservation tillage systems. Nitrogen management can be critical when grass winter cover crops are used as a surface residue. Advantages of using conservation tillage include soil and water conservation, improved soil chemical properties, reduction in irrigation requirements, reduced labor requirements, and greater nutrient recycling. However, disadvantages may include lower soil temperatures, which can affect maturity date; higher chemical input (desiccants and post-emergence herbicides); potential pest carryover in residues; and enhancement of some diseases.

Download Full-text

Spring-planted cover crops for weed control in soybean

Renewable Agriculture and Food Systems ◽

10.1017/s1742170521000107 ◽

2021 ◽

pp. 1-8

Author(s):

Katja Koehler-Cole ◽

Christopher A. Proctor ◽

Roger W. Elmore ◽

David A. Wedin

Keyword(s):

Weed Control ◽

Biomass Production ◽

Cover Crops ◽

Weed Management ◽

Block Design ◽

Weed Suppression ◽

Crop Species ◽

Cold Temperatures ◽

Weed Biomass ◽

Small Grains

Abstract Replacing tillage with cover crops (CC) for weed management in corn (Zea mays L.)-soybean [Glycine max (L.) Merr.] systems with mechanical weed control has many soil health benefits but in the western Corn Belt, CC establishment after harvest is hampered by cold temperatures, limited labor and few compatible CC species. Spring-planted CC may be an alternative, but information is lacking on suitable CC species. Our objective was to evaluate four spring-planted CC with respect to biomass production and weed suppression, concurrent with CC growth and post-termination. Cover crop species tested were oat (Avena sativa L.), barley (Hordeum vulgare L.), brown mustard [Brassica juncea (L.) Czern.] and yellow mustard (Brassica hirta Moench). They were compared to no-CC treatments that were either tilled pre- and post-planting of soybean (no-CC tilled) or not tilled at all (no-CC weedy). CC were planted in late March to early April, terminated 52–59 days later using an undercutter, and soybean was planted within a week. The experiment had a randomized complete block design with four replications and was repeated for 3 years. Mustards and small grains produced similar amounts of biomass (1.54 Mg ha−1) but mustard biomass production was more consistent (0.85–2.72 Mg ha−1) than that of the small grains (0.35–3.81 Mg ha−1). Relative to the no-CC weedy treatment, mustards suppressed concurrent weed biomass in two out of 3 years, by 31–97%, and small grains suppressed concurrent weed biomass in only 1 year, by 98%. Six weeks after soybean planting, small grains suppressed weed biomass in one out of 3 years, by 79% relative to the no-CC weedy treatment, but mustards did not provide significant weed suppression. The no-CC tilled treatment suppressed weeds each year relative to the no-CC weedy treatment, on average 87%. The ineffective weed control by CC reduced soybean biomass by about 50% six weeks after planting. While spring-planted CC have the potential for pre-plant weed control, they do not provide adequate early season weed suppression for soybean.

Download Full-text