Abstract
Development of more comprehensive and cost-effective integrated weed management systems is required to facilitate greater integrated weed management adoption by farmers. A field experiment was conducted at two locations to determine the combined effects of seed date (April or May), seed rate (recommended or 150% of recommended), fertilizer timing (applied in fall or spring), and in-crop herbicide dose (50% or 100% of recommended) on weed growth and crop yield. This factorial set of treatments was applied in four consecutive years within a spring wheat–spring canola–spring wheat–spring canola rotation in a zero-till production system. Both wheat and canola phases of the rotation were grown each year. Weed biomass was often lower with May than with April seeding because more weeds were controlled with preplant glyphosate. However, despite fewer weeds being present with May seeding, wheat yield was only greater in 1 of 7 site-years, and canola yield was never greater with May compared with April seeding. Higher crop seed rates had a consistently positive effect on reducing weed growth and the weed seedbank. Crop yield was sometimes greater, and never lower, with higher seed rates. Fertilizer timing did not have a large effect on crop yield, but applying N in the spring compared with fall was less favorable for weeds as indicated by lower weed biomass and a 20% decrease in the weed seedbank. In-crop herbicides applied at 50% compared with 100% doses often resulted in similar weed biomass and crop yield, especially when higher crop seed rates were used. Indeed, the weed seedbank at the conclusion of the 4-yr experiment was not greater with the 50% compared with 100% herbicide dose at one of two locations. This study demonstrates the combined merits of early seeding (April), higher crop seed rates, and spring-applied fertilizer in conjunction with timely but limited herbicide use to manage weeds and maintain high crop yields in rotations containing wheat and canola.
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Claims 13
Claim · model-written summary
May seeding often lowered weed biomass relative to April seeding.
- Taxon
- wheat–canola
Triticum aestivum.jpg?width=60)
Brassica napus var. napust0 - Treatment
- Maye0
- Interactor
- Weede0weed
- Outcome
- Weed biomasse0
- Direction
- lowere0
- Comparator
- Aprile0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e0“Weed biomass was often lower with May than with April seeding”
t0“wheat–canola”
Claim · model-written summary
May seeding increased wheat yield in only one of seven site years.
- Taxon
- wheatTriticum aestivumt0
- Treatment
- May seedinge0
- Outcome
- wheat yielde0
- Direction
- greatere0
- Value
- 1 of 7 site-yearse0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“However, despite fewer weeds being present with May seeding, wheat yield was only greater in 1 of 7 site-years”
t0“wheat–canola”
Claim · model-written summary
May seeding never increased canola yield relative to April seeding.
- Taxon
- canolaBrassica napus var. napuse0
- Treatment
- Maye0
- Outcome
- canola yielde0
- Direction
- never greatere0
- Comparator
- Aprile0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“canola yield was never greater with May compared with April seeding”
Claim · model-written summary
Higher crop seed rates reduced weed growth.
- Taxon
- wheat–canolaTriticum aestivumBrassica napus var. napust0
- Treatment
- Higher crop seed ratese0
- Interactor
- weede0weed
- Outcome
- weed growthe0
- Direction
- reducinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Higher crop seed rates had a consistently positive effect on reducing weed growth and the weed seedbank”
t0“wheat–canola”
Claim · model-written summary
Higher crop seed rates reduced the weed seedbank.
- Taxon
- wheat–canolaTriticum aestivumBrassica napus var. napust0
- Treatment
- Higher crop seed ratese0
- Interactor
- weede0weed
- Outcome
- weed seedbanke0
- Direction
- reducinge0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Higher crop seed rates had a consistently positive effect on reducing weed growth and the weed seedbank”
t0“wheat–canola”
Claim · model-written summary
Higher seed rates sometimes increased crop yield and never lowered it.
- Taxon
- wheat–canolaTriticum aestivumBrassica napus var. napust0
- Treatment
- higher seed ratese0
- Outcome
- Crop yielde0
- Direction
- greatere0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Crop yield was sometimes greater, and never lower, with higher seed rates”
t0“wheat–canola”
Claim · model-written summary
Fertilizer timing had little effect on crop yield.
- Taxon
- wheat–canolaTriticum aestivumBrassica napus var. napust0
- Treatment
- Fertilizer timinge0
- Outcome
- crop yielde0
- Direction
- did not have a large effecte0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Fertilizer timing did not have a large effect on crop yield”
t0“wheat–canola”
Claim · model-written summary
Spring N application reduced weed biomass relative to fall application.
- Taxon
- wheat–canolaTriticum aestivumBrassica napus var. napust0
- Treatment
- applying N in the springe0
- Interactor
- weedse0weed
- Outcome
- weed biomasse0
- Direction
- lowere0
- Comparator
- falle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“applying N in the spring compared with fall was less favorable for weeds as indicated by lower weed biomass”
t0“wheat–canola”
Claim · model-written summary
Spring N application decreased the weed seedbank by 20% relative to fall application.
- Taxon
- wheat–canolaTriticum aestivumBrassica napus var. napust0
- Treatment
- applying N in the springe0
- Interactor
- weedse0weed
- Outcome
- weed seedbanke0
- Direction
- decreasee0
- Value
- 20%e0
- Comparator
- falle0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“applying N in the spring compared with fall was less favorable for weeds as indicated by lower weed biomass and a 20% decrease in the weed seedbank”
t0“wheat–canola”
Claim · model-written summary
Half and full herbicide doses often gave similar weed biomass.
- Taxon
- wheat–canolaTriticum aestivumBrassica napus var. napust0
- Treatment
- In-crop herbicides applied at 50%e0
- Interactor
- weede0weed
- Outcome
- weed biomasse0
- Direction
- similare0
- Comparator
- 100% dosese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In-crop herbicides applied at 50% compared with 100% doses often resulted in similar weed biomass and crop yield”
t0“wheat–canola”
Claim · model-written summary
Half and full herbicide doses often gave similar crop yield.
- Taxon
- wheat–canolaTriticum aestivumBrassica napus var. napust0
- Treatment
- In-crop herbicides applied at 50%e0
- Outcome
- crop yielde0
- Direction
- similare0
- Comparator
- 100% dosese0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“In-crop herbicides applied at 50% compared with 100% doses often resulted in similar weed biomass and crop yield”
t0“wheat–canola”
Claim · model-written summary
At one of two locations, half dose herbicide did not increase the final weed seedbank relative to full dose.
- Taxon
- wheat–canolaTriticum aestivumBrassica napus var. napust0
- Treatment
- 50%e0
- Interactor
- weede0weed
- Outcome
- weed seedbanke0
- Direction
- not greatere0
- Comparator
- 100% herbicide dosee0
- Setting
- one of two locationse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the weed seedbank at the conclusion of the 4-yr experiment was not greater with the 50% compared with 100% herbicide dose at one of two locations”
t0“wheat–canola”
Claim · model-written summary
The authors recommend early seeding, higher seed rates, spring fertilizer and limited herbicide to manage weeds and maintain crop yield.
- Taxon
- wheat–canolaTriticum aestivumBrassica napus var. napust0
- Outcome
- early seeding (April), higher crop seed rates, and spring-applied fertilizer in conjunction with timely but limited herbicide usee0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the combined merits of early seeding (April), higher crop seed rates, and spring-applied fertilizer in conjunction with timely but limited herbicide use to manage weeds and maintain high crop yields”
t0“wheat–canola”
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See all 498 papers →8 of 10 groups shown: named compounds and organisms first, then groups whose results differ (checked claim by claim), then those with positive and negative results, then the smaller groups.
Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.