Weed Interference Impacts and Yield Recovery after Four Years of Variable Crop Inputs in No-Till Barley and Canola

A 2-yr (2009 to 2010), no-till (direct-seeded) “follow-up” study was conducted at five western Canada sites to determine weed interference impacts and barley and canola yield recovery after 4 yr of variable crop inputs (seed, fertilizer, herbicide). During the initial period of the study (2005 to 2008), applying fertilizer in the absence of herbicides was often worse than applying no optimal inputs; in the former case, weed biomass levels were at the highest levels (2,788 to 4,294 kg ha−1), possibly due to better utilization of nutrients by the weeds than by the crops. After optimal inputs were restored (standard treatment), most barley and canola plots recovered to optimal yield levels after 1 yr. However, 4 yr with all optimal inputs but herbicides led to only 77% yield recovery for both crops. At most sites, when all inputs were restored for 2 yr, all plots yielded similarly to the standard treatment combination. Yield “recovery” occurred despite high weed biomass levels (> 4,000 kg ha−1) prior to the first recovery year and despite high wild oat seedbank levels (> 7,000 seeds m−2) at the end of the second recovery year. In relatively competitive narrow-row crops such as barley and canola, the negative effects of high soil weed seedbanks can be mitigated if growers facilitate healthy crop canopies with appropriate seed and fertilizer rates in combination with judicious herbicide applications to adequately manage recruited weeds.

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

Weed Technology ◽

10.1614/wt-06-042.1 ◽

2007 ◽

Vol 21 (1) ◽

pp. 119-123 ◽

Cited By ~ 6

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.

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A cultural system to reduce weed interference in organic soybean

Renewable Agriculture and Food Systems ◽

10.1017/s1742170514000167 ◽

2014 ◽

Vol 30 (4) ◽

pp. 392-398 ◽

Cited By ~ 3

Author(s):

Randy L. Anderson

Keyword(s):

Cover Crops ◽

Alternative Tactics ◽

Cool Season ◽

Weed Biomass ◽

Cultural System ◽

Common Lambsquarters ◽

Weed Interference ◽

Oilseed Radish ◽

No Till ◽

Cultural Strategies

AbstractOrganic producers are seeking alternative tactics for weed control, so that they can reduce their need for tillage. In this study, we examined cultural strategies for controlling weeds during the transition from a cool-season crop to soybean. The study was arranged as a two-way factorial, with factors being choice of cool-season crop and tillage treatments. The cool-season crops were either spring wheat harvested for grain or an oat–pea mixture harvested for forage. Five tillage treatments, ranging from intensive tillage to no-till, were established following each cool-season crop. Two tillage treatments included the cover crops, oat plus oilseed radish. Soybean was planted the following growing season. Each soybean plot was split into two subplots: weed-free and weed-infested. A cultural system comprising oat/pea as a preceding crop with no-till and cover crops reduced weed biomass in soybean 63% compared to intensive tillage. Reduced weed biomass resulted because of delayed weed emergence and lower weed community density. Consequently, soybean yielded 14% more in this treatment than with the intensive tillage treatment when weeds were present. Weed community composition also differed between the two systems; horseweed and field dandelion were prominent in no-till, whereas common lambsquarters, redroot pigweed and buffalobur were prevalent in the tillage control. Other treatments did not control weeds better than intensive tillage. A cultural system approach may minimize the need for tillage during the interval between cool-season crops and soybean.

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Weed Control with Reduced Rates of Chlorimuron Plus Metribuzin and Imazethapyr in No-Till Narrow-Row Soybean (Glycine max)

Weed Technology ◽

10.1017/s0890037x00042536 ◽

1998 ◽

Vol 12 (1) ◽

pp. 32-36 ◽

Cited By ~ 9

Author(s):

William G. Johnson ◽

Jeffrey S. Dilbeck ◽

Michael S. Defelice ◽

J. Andrew Kendig

Keyword(s):

Glycine Max ◽

Weed Control ◽

Field Studies ◽

Weed Suppression ◽

Crop Response ◽

Soybean Production ◽

No Till ◽

Giant Foxtail ◽

The Difference ◽

Narrow Row

Field studies were conducted at three locations in 1993 and 1994 to evaluate weed control and crop response to combinations of glyphosate, metolachlor, 0.5 X and 1 X label rates of chlorimuron plus metribuzin applied prior to planting (PP), and 0.5 X and 1 X label rates of imazethapyr applied early postemergence (EPOST) or postemergence (POST) in no-till narrow-row soybean production. Giant foxtail densities were reduced with sequential PP followed by (fb) EPOST or POST treatments. Large crabgrass was reduced equivalently with all herbicide combinations involving chlorimuron plus metribuzin PP fb imazethapyr. Common cocklebur control was variable but was usually greater with treatments that included imazethapyr. Ivyleaf morningglory densities were not reduced with any herbicide combinations. Sequential PP fb EPOST or POST treatments tended to provide slightly better weed suppression than PP-only treatments, but the difference was rarely significant. Soybean yields with treatments utilizing 0.5 X rates were usually equal to 1 X rates.

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Effects of Tillage and Mulch on Weed Biomass and Sweet Corn Yield

Weed Technology ◽

10.1017/s0890037x00027305 ◽

1991 ◽

Vol 5 (3) ◽

pp. 545-552 ◽

Cited By ~ 25

Author(s):

Charles L. Mohler

Keyword(s):

Experimental Design ◽

Detrimental Effect ◽

Sweet Corn ◽

Cropping Systems ◽

Effective Control ◽

Corn Yield ◽

Living Mulch ◽

Weed Biomass ◽

Common Lambsquarters ◽

No Till

Sweet corn was grown with a living mulch of white clover, a dead mulch of rye, and without mulch, in both till and no-till conditions. Unplanted controls were also included in the experimental design. Corn yields were highest in clover treatments early in the experiment but lowest in later years. The declining yields in the clover living mulch were related to the strip application of glyphosate which allowed establishment of perennial and biennial weeds, notably dandelion and horseweed. These overwintering weeds apparently prevented effective control of summer annuals, especially redroot pigweed, common lambsquarters and large crabgrass, by atrazine and metolachlor. Presence of a rye mulch decreased weed biomass and had no detrimental effect on corn yield. In general, corn yield was not affected by tillage, although the number of marketable ears was reduced in the no-till treatments during the drought year of 1988. The much greater weed biomass in the unplanted control treatments showed the importance of crop competition for weed control in sweet corn cropping systems.

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The critical weed-free period in glyphosate-resistant soybean in Ontario is similar to previous estimates using glyphosate-susceptible soybean

Canadian Journal of Plant Science ◽

10.1139/cjps-2018-0049 ◽

2019 ◽

Vol 99 (4) ◽

pp. 437-443

Author(s):

Nader Soltani ◽

Robert E. Nurse ◽

Amit J. Jhala ◽

Peter H. Sikkema

Keyword(s):

Growth Stage ◽

Field Experiments ◽

Yield Loss ◽

Growth Stages ◽

Weed Species ◽

Weed Biomass ◽

Weed Density ◽

Weed Interference ◽

Beginning Of Flowering ◽

Minimal Reduction

A study consisting of 13 field experiments was conducted during 2014–2016 in southwestern Ontario and southcentral Nebraska (Clay Center) to determine the effect of late-emerging weeds on the yield of glyphosate-resistant soybean. Soybean was maintained weed-free with glyphosate (900 g ae ha−1) up to the VC (cotyledon), V1 (first trifoliate), V2 (second trifoliate), V3 (third trifoliate), V4 (fourth trifoliate), and R1 (beginning of flowering) growth stages, after which weeds were allowed to naturally infest the soybean plots. The total weed density was reduced to 24%, 63%, 67%, 72%, 76%, and 92% in Environment 1 (Exeter, Harrow, and Ridgetown) when soybean was maintained weed-free up to the VC, V1, V2, V3, V4, and R1 soybean growth stages, respectively. The total weed biomass was reduced by 33%, 82%, 95%, 97%, 97%, and 100% in Environment 1 (Exeter, Harrow, and Ridgetown) and 28%, 100%, 100%, 100%, 100%, and 100% in Environment 2 (Clay Center) when soybean was maintained weed-free up to the VC, V1, V2, V3, V4, and R1 stages, respectively. The critical weed-free periods for a 2.5%, 5%, and 10% yield loss in soybean were the V1–V2, VC–V1, and VC–V1 soybean stages in Environment 1 (Exeter, Harrow, and Ridgetown) and V2–V3, V2–V3, and V1–V2 soybean stages in Environment 2 (Clay Center), respectively. For the weed species evaluated, there was a minimal reduction in weed biomass (5% or less) when soybean was maintained weed-free beyond the V3 soybean growth stage. These results shows that soybean must be maintained weed-free up to the V3 growth stage to minimize yield loss due to weed interference.

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Using satellite navigation for seeding of wide-row and narrow-row crops

Research in Agricultural Engineering ◽

10.17221/6/2011-rae ◽

2011 ◽

Vol 57 (Special Issue) ◽

pp. S7-S13

Author(s):

M. Macák ◽

M. Žitňák ◽

L. Nozdrovický

Keyword(s):

Crop Production ◽

Spring Barley ◽

Satellite Navigation ◽

Navigation Systems ◽

Row Crops ◽

Satellite Navigation System ◽

Row Crop ◽

Narrow Row ◽

Correct Application ◽

Satellite Navigation Systems

The present paper is aimed at the use of satellite navigation of field machinery during seeding, this operation belonging to the most important field practises. Our attention was focused on the determination of the accuracy of the satellite navigation system based on using the correction signal real-time kinematic and its correct application for planting a wide-row crop (sunflower) and seeding a narrow-row crop (spring barley). The aim of the field experiment was also to specify the level of the necessary accuracy of satellite navigation systems during planting and seeding. The length of seeding/planting equipment was confronted with the accuracy of navigation of individual passes, especially when turning on the headlands. In the conclusion, the importance is highlighted of the automated tractor headland control during satellite navigation of combined field machines in the crop production.

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A mowing strategy to convert red clover to annual crops in organic farming

Renewable Agriculture and Food Systems ◽

10.1017/s1742170516000144 ◽

2016 ◽

Vol 32 (3) ◽

pp. 273-275 ◽

Cited By ~ 1

Author(s):

Randy L. Anderson

Keyword(s):

Organic Farming ◽

Cropping Systems ◽

Red Clover ◽

Corn Yield ◽

Weed Interference ◽

The Third ◽

Annual Crops ◽

No Till ◽

Conversion Method ◽

Weed Emergence

AbstractOrganic producers are interested in no-till cropping systems. In this study, we found that perennial clover can be converted to corn without tillage. Conversion tactics involved fall mowing in the third year of red clover, followed by between-row mowing of weeds and volunteer red clover in corn grown during the fourth year. Corn yielded 85% of the weed-free control with mowing conversion. In contrast, weed interference in tillage-based conversion and between-row tillage reduced corn yield 53%. Weed emergence was sixfold greater in the tilled conversion. Weeds were present in the corn row with mowing, but recently developed implements could control these weeds and further support a no-till conversion method.

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Dry Bean Morpho-Physiological Responses to Gradual Weed Biomass Accumulation

Notulae Scientia Biologicae ◽

10.15835/nsb518353 ◽

2013 ◽

Vol 5 (1) ◽

pp. 74-78

Author(s):

Hossein GHAMARI ◽

Goudarz AHMADVAND

Keyword(s):

Biomass Accumulation ◽

Physiological Traits ◽

Weed Competition ◽

Dry Matter Accumulation ◽

Dry Bean ◽

Weed Biomass ◽

Weed Interference ◽

Free Treatment ◽

Crop Cycle ◽

Number Of Branches

Field study was carried out in 2011 in west of Iran to assess responses of dry bean (Phaseolus vulgaris L.) morpho-physiological traits to gradual weed biomass accumulation. The treatments consisted of two different periods of weed interference, which weeds either infested the plots or removed for an increasing duration of time (0, 10, 20, 30, 40, 50 days) after crop emergence. Relative dominance and relative importance of weed species fluctuated over the crop cycle. As the duration of weed interference was increased, a declining trend of crop growth rate (CGR) was observed. When weeds were allowed to compete with crop throughout the crop cycle, maximum value of CGR was decreased from 25.57 g m-2 days in full season weed free treatment to 16.78 g m-2 days in full season weed infested treatment. Effect of treatments on leaf area index (LAI) was significant. Weed removal increased LAI but it could not significantly affect this trait, at the early of growing season. Weed interference caused a significant reduction on number of branches. The minimum number of branches was registered in full season weed infested treatment (2.58 branches per plant), while the maximum one was observed in the full season weed free treatment (4.25 branches per plant). Weed competition severely reduced crop yield. At 10 and 20 days after crop emergence, weed infestation could not significantly affect the yield. A negative relationship between weeds’ dry matter accumulation and LAI as well as number of branches was observed which signify the vulnerability of these morpho-physiological traits to weed competition.

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Efficacy and Economics of Cultivation for Weed Control in Potato (Solanum tuberosum)

Weed Technology ◽

10.1017/s0890037x00042925 ◽

1997 ◽

Vol 11 (2) ◽

pp. 257-264 ◽

Cited By ~ 14

Author(s):

Charlotte V. Eberlein ◽

Paul E. Patterson ◽

Mary J. Guttieri ◽

Jeffrey C. Stark

Keyword(s):

Solanum Tuberosum ◽

Weed Control ◽

Standard Treatment ◽

Control Efficacy ◽

Weed Biomass ◽

Common Lambsquarters ◽

Hairy Nightshade ◽

Green Foxtail ◽

One Year ◽

Control Net

A 3-year study was conducted in irrigated potato to compare weed control efficacy and economics of hilling plus one or two cultivations with the standard treatment of hilling plus a preemergence application of pendimethalin plus metribuzin. Trials were conducted under both weedy and weed-free conditions. Common lambsquarters and redroot pigweed were present in weedy treatments each year; significant populations of hairy nightshade and green foxtail also were present one year. When weed populations were low or moderate (< 45 plants/m2), total weed biomass in the hilling plus one cultivation treatment was reduced 98 to 99% relative to the weedy control, and U.S. No. 1 tuber yields were equal to the standard treatment. However, when weed populations were high (145 plants/m2), hilling plus one cultivation and hilling plus two cultivations provided only 30% and 61% reduction in weed biomass, respectively, and U.S. No. 1 tuber yields were 35% and 13% less, respectively, than the standard treatment. The standard treatment provided 99% reduction in total weed biomass each year, and yields were equal to the weed-free, hill plus no cultivation control. Net return was $37 to $100/ha higher for the hilling plus one cultivation treatment compared to the standard treatment when weed populations were moderate or low, but was $808/ha less than the standard treatment when weed populations were high.

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