Abstract
Sustainable cropping systems are essential for agronomic, economic, and environmental reasons. Data from a winter wheat (Triticum aestivum L.)/summer fallow rotation experiment, in eastern Oregon, was used to evaluate long-term effects of tillage, N, soil depth, and precipitation on yield. The soil is a Walla Walla silt loam (coarse-silty, mixed, mesic Typic Haploxeroll). The experiment consisted of three tillage treatments (moldboard plow, offset disk, and subsurface sweep) and six N treatments. Four main time periods (1944–1951, 1952–1961, 1962–1987, 1988–1997), were identified, within which experimental treatments were consistently maintained. Depth to bedrock ranged from 1.2 to 3.0 m. Yield was significantly greater (>300 kg ha−1) for the moldboard plow than for the subsurface sweep in all time periods. Yield was generally greater (>100 kg ha−1) for the moldboard plow than for the offset disk, but only significantly in Time Periods 3 and 4. For Periods 1 and 2, the addition of N fertilizer tended to produce higher yields, regardless of quantity or distribution of rainfall. For Period 3, yield did not increase with the addition of more than 45 kg N ha−1, which we attribute to below-normal precipitation. For Period 4, when precipitation was above average, yield increased with the addition of up to 90 kg N ha−1. Results demonstrated that despite beneficial effects on soil properties, conservation tillage has tended to be less productive for this cropping system than moldboard plowing, probably due to lack of downy brome weed control in the conservation tillage systems.
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Claims 6
Claim · model-written summary
Moldboard plowing yielded significantly more winter wheat than subsurface sweeping in all periods, by over 300 kg ha−1.
- Taxon
- winter wheat
Triticum aestivumt0 - Treatment
- moldboard plowe0
- Outcome
- Yielde0
- Direction
- greatere0
- Value
- >300 kg ha−1e0
- Qualifier
- all time periodse0
- Comparator
- subsurface sweepe0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Yield was significantly greater (>300 kg ha−1) for the moldboard plow than for the subsurface sweep in all time periods.”
t0“Winter Wheat”
Claim · model-written summary
Moldboard plowing generally yielded over 100 kg ha−1 more winter wheat than offset disking, significantly so only in periods 3 and 4.
- Taxon
- winter wheatTriticum aestivumt0
- Treatment
- moldboard plowe0
- Outcome
- Yielde0
- Direction
- greatere0
- Value
- >100 kg ha−1e0
- Qualifier
- Time Periods 3 and 4e0
- Comparator
- offset diske0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Yield was generally greater (>100 kg ha−1) for the moldboard plow than for the offset disk, but only significantly in Time Periods 3 and 4.”
t0“Winter Wheat”
Claim · model-written summary
Adding nitrogen fertilizer tended to increase winter wheat yields in periods 1 and 2 regardless of rainfall quantity or distribution.
- Taxon
- winter wheatTriticum aestivumt0
- Treatment
- addition of N fertilizere0
- Outcome
- yieldse0
- Direction
- highere0
- Qualifier
- regardless of quantity or distribution of rainfalle0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For Periods 1 and 2, the addition of N fertilizer tended to produce higher yields, regardless of quantity or distribution of rainfall.”
t0“Winter Wheat”
Claim · model-written summary
In period 3, winter wheat yield did not increase with nitrogen addition above 45 kg N ha−1.
- Taxon
- winter wheatTriticum aestivumt0
- Treatment
- addition of more than 45 kg N ha−1e0
- Outcome
- yielde0
- Direction
- did not increasee0
- Qualifier
- below-normal precipitatione0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For Period 3, yield did not increase with the addition of more than 45 kg N ha−1, which we attribute to below-normal precipitation.”
t0“Winter Wheat”
Claim · model-written summary
In period 4, above-average precipitation accompanied yield increases with nitrogen addition up to 90 kg N ha−1.
- Taxon
- winter wheatTriticum aestivumt0
- Treatment
- addition of up to 90 kg N ha−1e0
- Outcome
- yielde0
- Direction
- increasede0
- Qualifier
- precipitation was above averagee0
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“For Period 4, when precipitation was above average, yield increased with the addition of up to 90 kg N ha−1.”
t0“Winter Wheat”
Claim · model-written summary
The authors concluded conservation tillage was less productive than moldboard plowing in this winter wheat system.
- Taxon
- winter wheatTriticum aestivumt0
- Treatment
- conservation tillagee0
- Interactor
- downy brome
Bromus tectorume0weed - Outcome
- less productivee0
- Direction
- less productivee0
- Comparator
- moldboard plowinge0
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“Results demonstrated that despite beneficial effects on soil properties, conservation tillage has tended to be less productive for this cropping system than moldboard plowing, probably due to lack of downy brome weed control in the conservation tillage systems.”
t0“Winter Wheat”
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See all 3,438 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.