Abstract
Sunflower ( Helianthus annuus L.) is a warm‐season, intermediate water‐use crop that can add diversity to dryland crop rotations. Reduced tillage systems may enhance sunflower yield in intensive cropping systems. A 12‐year study was conducted to determine how sunflower cultivars of early and medium maturity respond to tillage system (conventional‐till, CT; minimum‐till, MT; no‐till, NT) and N fertilization (34, 67, and 101 kg N ha −1 ) within a dryland spring wheat ( Triticum aestivum L.)–winter wheat–sunflower rotation. Averaged across N rates, cultivars, and years, sunflower seed yields were greater with MT (1550 kg ha −1 ) than with NT (1460 kg ha −1 ) and CT (1450 kg ha −1 ). Increasing N rate above 34 kg N ha −1 generally increased grain yield, but varied from year to year. The tillage × N interaction showed that the highest seed yields were obtained with NT (1638 kg ha −1 ) and MT (1614 kg ha −1 ) at 101 kg N ha −1 . Total plant‐available water (TPAW) of <350 mm greatly reduced sunflower yield potential, due to water stress, compared with yields for 350 to 500 mm of TPAW. TPAW > 500 mm did not result in increased sunflower yields over those with 350 to 500 mm TPAW. Yield differences between cultivar maturity classes varied from year to year and with tillage and N level. At the lowest N rate, weeds were more problematic in NT than in CT and MT plots. More N fertilizer may be needed with NT to optimize sunflower yields than with CT and MT, because of less residual soil NO 3 –N with NT. Results indicate that producers in the northern Great Plains can use sunflower successfully in annual cropping systems, particularly if MT and NT are used with adequate N fertilization.
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Claims 10
Claim · model-written summary
Minimum tillage yielded 1550 kg ha −1 sunflower seed, exceeding no-till and conventional tillage.
- Taxon
- sunflower
Helianthus annuuse0 - Treatment
- MTe0
- Outcome
- sunflower seed yieldse0
- Direction
- greatere0
- Value
- 1550 kg ha −1e0
- Comparator
- NTe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“sunflower seed yields were greater with MT (1550 kg ha −1 ) than with NT (1460 kg ha −1 ) and CT (1450 kg ha −1 )”
Claim · model-written summary
Increasing nitrogen above 34 kg N ha −1 generally increased yield, varying by year.
- Taxon
- SunflowerHelianthus annuust0
- Treatment
- N rate above 34 kg N ha −1e0
- Outcome
- grain yielde0
- Direction
- increasede0
- Qualifier
- varied from year to yeare0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Increasing N rate above 34 kg N ha −1 generally increased grain yield, but varied from year to year”
t0“Sunflower”
Claim · model-written summary
No-till at 101 kg N ha −1 produced a highest seed yield of 1638 kg ha −1.
- Taxon
- SunflowerHelianthus annuust0
- Treatment
- NTe0
- Outcome
- seed yieldse0
- Direction
- higheste0
- Value
- 1638 kg ha −1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the highest seed yields were obtained with NT (1638 kg ha −1 ) and MT (1614 kg ha −1 ) at 101 kg N ha −1”
t0“Sunflower”
Claim · model-written summary
Minimum tillage at 101 kg N ha −1 produced a highest seed yield of 1614 kg ha −1.
- Taxon
- SunflowerHelianthus annuust0
- Treatment
- MTe0
- Outcome
- seed yieldse0
- Direction
- higheste0
- Value
- 1614 kg ha −1e0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the highest seed yields were obtained with NT (1638 kg ha −1 ) and MT (1614 kg ha −1 ) at 101 kg N ha −1”
t0“Sunflower”
Claim · model-written summary
Water below 350 mm greatly reduced sunflower yield potential compared with 350 to 500 mm.
- Taxon
- sunflowerHelianthus annuuse0
- Outcome
- sunflower yield potentiale0
- Direction
- reducede0
- Comparator
- 350 to 500 mm of TPAWe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Total plant‐available water (TPAW) of <350 mm greatly reduced sunflower yield potential, due to water stress, compared with yields for 350 to 500 mm of TPAW”
Claim · model-written summary
Water above 500 mm did not increase sunflower yield over 350 to 500 mm.
- Taxon
- sunflowerHelianthus annuuse0
- Outcome
- sunflower yieldse0
- Comparator
- 350 to 500 mm TPAWe0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“TPAW > 500 mm did not result in increased sunflower yields over those with 350 to 500 mm TPAW”
Claim · model-written summary
Yield differences between cultivar maturity classes varied by year, tillage and nitrogen.
- Taxon
- SunflowerHelianthus annuust0
- Outcome
- Yield differences between cultivar maturity classese0
- Setting
- year to yeare0
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Yield differences between cultivar maturity classes varied from year to year and with tillage and N level”
t0“Sunflower”
Claim · model-written summary
At low nitrogen, weeds were more problematic under no-till than conventional and minimum tillage.
- Taxon
- SunflowerHelianthus annuust0
- Treatment
- NTe0
- Interactor
- weedse0weed
- Outcome
- weedse0
- Direction
- more problematice0
- Comparator
- CT and MT plotse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“At the lowest N rate, weeds were more problematic in NT than in CT and MT plots”
t0“Sunflower”
Claim · model-written summary
More nitrogen may be needed under no-till to optimize sunflower yield.
- Taxon
- sunflowerHelianthus annuuse0
- Outcome
- More N fertilizer may be needed with NT to optimize sunflower yieldse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“More N fertilizer may be needed with NT to optimize sunflower yields than with CT and MT, because of less residual soil NO 3 –N with NT”
Claim · model-written summary
Annual sunflower cropping is feasible in the northern Great Plains with minimum or no tillage and adequate nitrogen.
- Taxon
- sunflowerHelianthus annuuse0
- Outcome
- use sunflower successfully in annual cropping systemse0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“producers in the northern Great Plains can use sunflower successfully in annual cropping systems, particularly if MT and NT are used with adequate N fertilization”
The same questions in other papers
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- positive
- positive
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See all 11 papers →tillage · yield · Helianthus annuus (common sunflower)Positive and negative results
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- no effect
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See all 70 papers →nitrogen · yield · Helianthus annuus (common sunflower)Positive and negative results
181 papers in the same direction as this paper · 10 in the opposite direction · 4 reporting no difference from an alternative
- positive
- positive
- negative
192 papers more in this group
See all 196 papers →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.